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<DR.  RUDOLPH  DIESEL 

The  Inventor  of  the  Engine  operating  under  "Constant  Pressure",  named  after 

its  Originator,  the  <Diesel  Engine.     <Born  1858,  (Disappeared  September 

30th,  1913  while  crossing  the  ^British  Channel  from 

Antwerp  to  Harwich,  England. 


The  ,:^:. 

-  20th  CENTURY  GUIDE 

FOR 

DIESEL  OPERATORS 

A    PRACTICAL    BOOK    FOR    OPERATORS,    SCHOOLS, 

LIBRARIES  AND  THOSE  INTERESTED 

IN  DIESEL  OPERATION 


PROFUSELY  ILLUSTRATED 


By 
JULIUS  ROSBLOOM 

Co-Atithor  of 
"The  20th  Century  Guide  for  Marine  Engineers" 

(Ramsey  &  Rosbloom) 
"The  20th  Century  Guide  for  Automobile  Operators,"  etc. 

And 

ORVILLE  R.  SAWLEY 
Internal  Combustion  Engineer 


Published  by: 

WESTERN   TECHNICAL  BOOK   COMPANY,   Inc. 
SEATTLE,    WASHINGTON. 


_/ 
library 


Copyright  1922  by  J.  Rosbloom  and  O.  R.  Sawley. 
(All  Rights  Reserved.) 


Press  of  Peters  Publishing  Company, 
Seattle,  Washington. 


FOREWORD 


IN  the  preparation  of  the  "20th  Century  Guide  for  Diesel 
Operators"  all  data  has  been  carefully  selected  to  suit 
the  person  engaged  in   the  profession  dr  for  the  use 
in  the  study  of  Internal  Combustion  Engineering. 

The  primary  object  of  this  valuable  addition  to  tech- 
nical publications  on  the  subject  of  Internal  Combustion 
machinery  and  such  information  as  this  book  contains,  is  to 
instruct  those  interested  in  this  prime  mover  in  practical 
form. 

The  Authors  are  confident  that  this  book  will  prove 
beneficial  to  those  aspiring  to  knowledge,  and  with  this 
end  in  view  they  feel  that  their  work  has  not  been  in  vain. 

JANUARY,  1922. 

THE  AUTHORS. 


480031 


WE   APPRECIATE   THE   SERVICES  AND   FURNISHING 
OF  DATA  BY 

Engineering  Officers  of  the  United  States  Navy,  in  particu- 
lar, the  late  'Commandant  U.  S.  N.  Captain  Barthalow, 
Ensign  G.  F.  De  Grave,  U.  'S.  N.,  Internal  Combustion  En- 
gineers, Operating  Engineers  engaged  in  practical  opera- 
tion of  Diesel  power,  Manufacturers  of  Internal  Combustion 
Machinery,  etc.,  who  so  courteously  assisted  us  in  making 
it  possible  to  produce  the  "20th  'Century  Guide  for  Diesel 
Operators." 

We  also  desire  to  acknowledge  our  gratitude  to  the 
Hon.  Herbert  Hoover,  Secretary  of  Commerce,  in  so  kindly 
encouraging  the  publication  of  the  "Rules  for  Obtaining 
U.  S.  Licenses  for  Engineers  on  Motor-Driven  Ships,"  and 
Mr.  Harry 'C.  Lord,  Federal  Inspector  United  States  Inspec- 
tion Service,  Port  of  Seattle,  Washington  for  his  valuable 
suggestions. 

The  co-operation  of  Mr.  L.  B.  Chapman,  Professor  of 
Naval  Architecture  and  Marine  Engineering,  Lehigh  Uni- 
versity, Bethlehem,  Pa.,  is  highly  appreciated. 

Our  thanks  is  also  extended  to  the  editorial  staffs  of 
the  "Motorship,"  "Marine  Engineering,"  "Pacific  Shipping 
Illustrated,"  "Railway  .&  Marine  Review,"  etc.,  for  their 
courtesy  in  extending  the  authors  of  "The  20th  Century 
Guide  for  Diesel  Operators"  their  liberal  assistance. 

The  services  of  Mr.  O.  J.  Hansen,  M.  E.,  in  compilation 
of  the  subject  matter,  is  highly  appreciated. 

THE  AUTHORS. 


WE  ARE  INDEBTED  TO   FOLLOWING   FIRMS  IN  THE 

PREPARATION     OF     "THE     20th     CENTURY 

GUIDE  FOR  DIESEL   OPERATORS" 

Bethlehem  Steel  Corporation 

General  Electric  Company 

Wes'tinghouse  Electric  Manufacturing  Company 

Griscom-Russell  Company 

Dow  Diesel  &  Pump  Works 

Allis-Chalmers  Company 

De  Laval  Company 

Busch-Sulzer  Diesel  Engine  Company 

Worthington  Pump  &  Engine  Works 

Nordberg  Manufacturing  Company 

Sullivan  Compressor  Co. 

Burmeister  &  Wain  Company 

Pacific  Diesel  Engine  Company 

Atlas  Imperial  Diesel  Engine  Co. 

New  London  Ship  &  Engine  Company 

Vickers,  Ltd. 

Ingersoll-Rand  Company 

The  Power  Manufacturing  Company 

Seattle  Machine  Works 

Ansaldo-Giorgio  Company 

Blohm  &  Voss  Company 

Mclntosh  &  Seymour  Company 

Winton  Diesel  Engine  Company 

Bolinder's  Company 

Fairbanks,  Morse  Company 

Manzel  Bros.  Company 

Edison  Electric  Company 

Cutler-Hammer  Corporation 

Sperry  Gyroscope  Co. 

Mietz  Corporation 

Standard  Oil  Company 

Lombard-McCarthy  Company 

Western  Miachinery  Company 

Fulton  Diesel  Engine  Company 

Paragon e  Gear  Works 

'Carlysle-Johnson  Machinery   Company 

C.  H.  Wheeler  Company 

Hoppe's  Manufacturing  Company 

Burt  Manufacturing  Company 

Gullowsen  Grei  Engine  Company 

The  P'neumercator  Company 


Allan-Clmningham.  Company 

Baltimore  Oil  Engine  Company 

The  Taylor  Instrument  Company 

The  De  La  Vergne  Oil  Engine  Company 

The  De  Laval  Separator  Company 

Schutte  &  Koerting  Company 

Chicago  Pneumatic  Tool   Company 

Ashton  Valve  Company 

Aspinall  Governor  Company 

The  Hadfield-Penfield  Steel  Company 

C.  H.  Wheeler  Company 

Craig  Machinery  Company 

Lombard  Governor  Company 

Kahlenberg  Brothers 

National  Transit  Pump  &  Machine  Company 

The  Maxim  Silencer  Company 

Elliott  Company 

Cumings  Oil  Engine  Company 

Etc.,  Etc. 


PREFACE 

ONE  has  to  marvel  at  the  advance  made  in  the  improvements  on  the 
Diesel  engine  in  the  last  ten  years,  while  it  is  to  be  regretted  that 
the  literature  on   the   subject,   in   comprehensive  form,   has   been 
noticeably  lacking.    The  task  of  the  'authors  has  been  to  link  up  the  won- 
derful mechanical  advance  with  reliable  data  for  the  engineer  in  the  form 
of  a  complete  treatise  and  text  on  Diesel  Operation  brought  u,p  to  date. 

The  importance  of  Diesel  power  cannot  be  overestimated.  Even  the 
'most  skeptically  inclined  engineers  of  a  few  years  back,  as  well  as  others 
interested  in  power  generation  who  were  temipted  to  treat  the  matter 
lightly  have  been  compelled  by  the  course  of  events  to  look  upon  the 
Diesel  engine  as  a  prime  mover  which  is  deserving  of  the  highest  con- 
sideration. The  fact  that  its  results  have  been  of  such  a  tremendous 
nature  in  minimizing  waste,  space  and  cost,  etc.,  without  impairing  effi- 
ciency explains  the  trend  towards  universal  adoption  in  certain  lines  of 
engineering. 

The  Diesel  Engine  is  here  to  stay,  and  the  progressive  engineer 
realizing  that  fact  finds  it  his  duty  to  extend  his  knowledge  into  the 
Diesel  field,  and,  as  a  consequence,  demands  more  reliable  and  timely 
data  on  the  subject.  The  authors  have  tried  to  answer  the  engineer's 
call  by  producing  "The  Twentieth  Century  Guide  for  Diesel  Operators," 
in  fact,,  they  have  gone  farther,  and  tried  to  make  this  work  satisfy  the 
needs  of  all  who  are  seeking  enlightenment  in  this  branch  of  engineer- 
ing, whether  they  be  students  or  experts.  Neither  time  nor  expense  has 
been  spared  in  an  effort  to  make  this!  work  a  success,  and  by  success  is 
meant  "A  world's  standard  book."  The  authors  feel  that  in  some  ways 
they  have  accomplished  much  they  set  out  to  do,  as  there  is  reliable  data 
both  original  and  obtained  which  has  never  been  within  reach  of  the 
engineering  world  before  the  completion  of  this  publication,  beyond  alto- 
gether the  standard  data  expected  in  a  text  of  this  kind.  The  substance 
is  international  in  character  and  the  scope  covers  both  land  and  sea  oper- 
ation. The  writers  have  done  their  utmost  to  assemble  in  compact  form 
all  the  world  knows  of  Diesel  machinery  up  to  the  present  time,  and 
having  done  their  utmost,  they  now  invite  constructive  criticism  with 
the  object  of  making  future  editions  not  only  abreast  of  modern  invention 
but  also  to  the  complete  satisfaction  of  the  engineering  profession. 

THE  AUTHORS. 


TABLE  OF  CONTENTS 


Chapter     1.  Technical  Terms  as  Applied  to  Diesel  Machinery. 

Chapter     2.  Theory. 

Chapter     3.  Miscellaneous  Formulas. 

Chapter     4.  Principles  of  Diesel  Operation. 

Chapter     5.  Liquid  Substances. 

Chapter     6.  Questions  and  Answers  on  Diesel  Operation, 

Chapter     7.  Fuel  Feed  and  Ignition. 

Chapter     8.  Principles    of   'Construction. 

Chapter     9.  Auxiliary  Machinery  and  Accessories. 

Chapter  10.  Detailed  Description  of  Diesel  Engines. 

Chapter  11.  Diesel  Electric  Propulsion. 

Chapter  12.  Low  Compression  Oil  Engines. 

Chapter  13.  Compressors. 

Chapter  14.  Pumps. 

Chapter  15.  Batteries. 

Chapter  16.  U.  S.  Rules  for  Licensing  of  Engineers  on  Motor- 
ships,  Lloyd's  Rules,  Extract  from  Rules  American 
Bureau  of  Shipping. 

See  General  Index  in  Back  of  Book. 


CHAPTER  I. 


TECHNICAL   TERMS,  AS   APPLIED   TO    DIESEL    MACHINERY 

Mechanical  Efficiency: 

The  mechanical  efficiency  of  the  Diesel  Engine  is  the  net  effective 
power  developed  in  the  engine  cylinder  remaining  after  the  power  is  ab- 
sorbed by  the  moving  parts  of  the  engine  and  by  frictional  resistance  de- 
ducted. The  mechanical  efficiency  is  expressed  as  the  ratio  between  the 
effective  power  of  the  engine  as  measured  by  a  brake  on  the  engine  shaft. 
The  mechanical  efficiency  of  a  Diesel  engine  is  influenced  by  numerous 
factors,  'such  as  the  type  and  size  of  the  engine,  the  quality  of  the  ma- 
terial and  workmanship,  the  care  given  to  details  in  erecting,  the  lubri- 
cating system,  including  the  quantity  and  the  quality  of  the  lubricating 
oil  used.  If  too  much  cooling  water  is  used,  frictional  resistance,  due 
to  cylinder  contraction,  may  be  greatly  increased.  As  the  internal  power 
and  friction  of  an  engine  are  nearly  constant  regardless  of  load,  the  me- 
chanical efficiency  decreases  in  the  engine  load. 

The  mechanical  efficiency  of  engines  having  a  two-stroke  cycle  is 
lower  than  that  of  engines  having  a  four-stroke  cycle  as,  in  addition  to 
the  power  required  by  the  injection  air  compressor,  there  is  that  re- 
quired by  the  scavenging  pump. 

The  mechanical  efficiencies  of  four-stroke  engines  at  full  load  vary 
from  75  to  80  per  cent,  80  per  cent  being  usual  for  high  grade,  low-speed 
engines  of  medium  and  large  powers.  The  engine  efficiency,  exclusive 
of  the  air  compressor,  is  85  to  90  per  cent. 

The  mechanical  efficiency  of  engines,  having  a  two-stroke  cycle, 
seldom  exceeds  70  per  cent  and  may  be  as  low  as  65  per  cent  in  high 
speed  engines.  The  distribution  of  power  losses  in  two-stroke  and  four- 
stroke  engines  depends  a  great  deal  on  the  competency  of  the  man  in 
charge. 

Thermal   Efficiency: 

The  thermal  efficiency  of  a  Diesel  Engine  is  the  ratio  between  the 
equivalent  in  heat  units  of  1  horse-power  and  the  number  of  heat  units 
actually  consumed  by  the  engine  in  developing  1  horse-power.  If  based 
on  the  indicated  horse-power,  it  is  indicated  horse-power  efficiency,  if 
based  on  the  brake  horse-power,  it  is  the  effective  thermal  efficiency. 

The  thermal  efficiency  depends  chiefly  on  'the  thermodynaimic  cycle 
of  the  Diesel  Engine,  and  is  affected  by  the  compression  ratio  (ratio  be- 
tween total  cylinder  volume  and  clearance  volume  at  the  end  of  com- 
pression) as  well  as  the  cut-off  ratio  (ratio  between  cylinder  volume  at 
time  fuel  valve  closes  and  volume  at  inner  dead  center  of  piston  or 
clearance  volume). 


14  TECHNICAL  TERMS 

The  indicated  thermal  efficiency  increases  with  a  decrease  in  the 
cutoff  ratio  which  contributes  to  'the  economy  of  the  Diesel  engine  at 
fractional  loads,  the  iuel  consumption  per  horse-power-hour  remaining 
nearly  constant  between  full  and  three-fourths  loads,  and  increasing 
only  slightly  at  one-half  load.  The  ignition  of  the  -fuel  could  be  effected 
at  lower  pressures,  but  high  compression  is  essential  to  high  engine 
economy  in  Diesel  Engines. 

The  mechanical  efficiency  of  the  engine  naturally  influences  its  fuel 
economy  (thermal  efficiency)  also,  but  to  a  minor  degree. 

The  indicated  thermal  efficiency  of  the  Diesel  engine  having  a  four- 
stroke  cycle,  varies  from  45  per  cent  at  full  load  to  47  per  cent  at  half 
load,  and  the  effective  thermal  efficiency  from  37  per  cent 'at  full  load 
to  30  per  cent  at  half  load,  which  represents  the  best  practice.  As  re- 
gards to  engines  having  a  twojstroke  cycle,  the  figures  are  10  to  15  per 
cent  lower. 

Volumetric  Efficiencies: 

The  volumetric  efficiency  is  the  ratio  between  the  weight  of  a  cylin- 
der full  of  air  at  the  completion  of  the  suction  stroke  and  the  weight  of 
a  similar  volume  of  standard  temperature  and  pressure.  It  can  be  de- 
termined by  measuring  the  partial  pressure  of  the  air  during  the  suc- 
tion stroke  and  dividing  it  by  the  atmospheric  pressure. 

The  construction  of  the  engine,  its  piston  speed,  its  valve  gear,  and 
temperature  are  factors  that  influence  the  volumetric  efficiency. 

The  volumetric  efficiency  of  an  engine  having  a  four-stroke-cycle 
differs  from  that  of  an  engine  having  a  two-stroke  cycle.  The  volumetric 
efficiency  influences  the  specific  duty  of  the  Diesel  engine.  During  the 
suction  stroke  of  the  four-cycle  engine,  the  air  becomes  somewhat  rare- 
fied, so  that  the  lower  the  volumetric  efficiency,  the  lower  is  the  weight 
of  oxygen  in  a  cylinder  full  of  air.  The  maximum  quantity  of  fuel  'that 
can  be  turned  by  the  air  (oxygen)  charges  is  also  proportionately  lower 
with  lower  volumetric  efficiency. 

The  volumetric  efficiency  of  engines  having  a  two-stroke  cycle  1-s 
generally  below  unity,  notwithstanding  the  fact  that  the  cylinders  are 
filled  with  slightly  compressed  air,  as  it  is  not  possible  to  scavenge  or 
remove  all  the  gases  of  combustion,  which  vitiate  the  burning  power  of 
the  air  charge.  To  determine  the  volumetric  efficiency  of  engines  hav- 
ing a  two-stroke  cycle,  it  is  not  sufficient  to  know  the  pressure  of  the 
air  that  filled  the  cylinder  (before  compression  begins) ;  this  value  must 
be  multiplied  by  the  percentage  of  pure  air  present  in  the  total  weight 
of  gas  filling  the  cylinder. 

For  slow-speed  four-stroke  engines  a  volumetric  efficiency  of  90  per 
cent  can  be  reached,  which  decreases  to  85  per  cent  for  high-speed  en- 
gines and  for  extreme  speeds  may  be  lower.  These  values  <pre-<suppose 
high-grade  engines  with  mechanically  operated  valves. 

Scavenging   Efficiencies: 

The  scavenging  efficiency  in  a  two-cycle  engine  is  the  ratio  between 


TECHNICAL  TERMS  15 

the  weight  of  the  air  contained  in  the  cylinder  at  the  comimencemen't 
of  the  compression  stroke  and  that  of  the  mixture  of  air  and  burnt  gas. 
The  efficiency  of  tihe  charge  is  denned  as  the  ratio  between  the 
amount  of  pure  air  in  the  cylinder  at  the  commencement  of  the  com- 
pression and  the  total  cylinder  volume,  whilst  the  useful  scavenging  ef- 
fect is  the  ratio  between  the  same  amount  of  pure  air  and  the  output 
of  the  scavenging  pump. 

Ratio  of  Expansion: 

The  thermal  efficiency  at  its  maximum  is  due  to  the  increased  tem- 
perature when  the  engine  is  at  its  highest  production.  The  accomplished 
results  in  creating  the  full  energy  out  of  the  working  mediums,  and  the 
working  substance. 

Laws  of  Thermodynamics: 

In  the  conversion  of  heat  into  mechanical  energy,  one  unit  of  heat 
is  lost  for  every  778  foot-pounds  of  energy  obtained;  and  conversely,  in 
the  production  of  heat  by  mechanical  means,  one  unit  of  heat  is  ob- 
tained from  every  778  pounds  of  energy  expended.  It  is  also  known,  that 
it  is  impossible  for  a  self-acting  engine  to  convey  heat  from  one  body 
to  another  at  a  higher  temperature  without  the  aid  of  external  assist- 
ance. 

Specific  Heat  at  Constant  Pressure: 

The  specific  heat  at  constant  pressure  is  the  amount  of  heat  ab- 
sorbed by  the  unit  mass  of  gas  when  its  temperature  is  raised  by  one 
degree  on  the  thermometric  scale,  the  pressure  being  kept  constant,  but 
the  volume  being  allowed  to  increase. 

Specific  H-eat  at  Constant  Volume: 

The  specific  heat  at  constant  volume  is  the  amount  of  heat  absorbed 
by  the  unit  mass  of  gas  when  its  temperature  is  increased  by  one  degree 
on  the  thermometric  scale,  its  volume  being  kept  constant,  so  that  the 
addition  of  heat  results  in  an  increase  of  pressure. 

Since  the  combustive  element  when  heated  at  constant  pressure  ne- 
cessarily expands  and  does  work,  the  specific  heat  at  constant  pressure 
is  naturally  greater  than  that  at  constant  volume  by  the  amount  of  heat 
used  up  in  doing  that  work;  therefore  the  specific  heat  at  constant  vol- 
ume is  commonly  expressed  as  the  true  specific  heat,  but  both  values 
require  to  be  considered  in  connection  with  the  problems  of  the  internal 
combustion  machinery. 

Isothermal  Expansion: 

In  isothermal  expansion  the  temperature  of  the  combustible  element 
during  the  whole  expansion  remains  unaltered,  and  hence  the  Internal 
energy  in  the  heat  value  remains  unaltered,  and  the  heat  created  is 
equivalent  to  the  power  in  proportion  to  work  externally. 

Adiabatic  Expansion. 

The  adiabatic  expansion  means  that  the  heat  is  maintained  on  an 
equal  base,  or  heat  is  neither  gained  nor  lost  during  the  expansion.  The 


16  TECHNICAL  TERMS 

whole  of  the  heat  being  employed  in  doing  external  work,  and  it  is  evi- 
dent at  once  that  this  can  hardly  be  realized  in  practice  on  Diesel  work. 

Sensible  and  Latent  Heats: 

Sensible  and  latent  heats  must  be  carefully  distinguished  in  study- 
ing the  action  of  heat  on  matter.  The  term  "sensible  heat"  is  easily 
understood,  but  we  miay  say,  that  sensible  and  latent  heat  represents 
latent  and  sensible  work;  that  the  former  is  actual,  kinetic,  heat  energy, 
capable  of  transformation  into  mechanical  energy,  or  vice  versa,  of 
masses,  and  into  mechanical  work;  while  the  latter  form  is  not  heat, 
but  is  the  equivalent  of  'heat  transformed  to  produce  a  visible  effect  in 
the  performance  of  molecular,  or  internal  as  well  as  external  work,  and 
visible  alteration  of  volume  and  other  physical  conditions. 

It  is  seen  that  heat  may  become  "latent"  through  any  transforma- 
tion which  results  in  a  denned  physical  change,  produced  by  expansion 
of  any  substance  in  consequence  of  such  transmutation  into  internal 
and  external  work;  whether  it  be  simple  increase  of  volume  or  such  in- 
crease with  change  of  physical  state. 

Latent  Heat  of  Expansion: 

The  latent  heat  of  expansion  may  be  defined  as  that  heat  which  is 
demanded  to  produce  an  increase  of  volume,  as  distinguished  from  that 
untransformed  heat  which  is  absorbed  by  the  substance  to  produce  ele- 
vation of  temperature.  The  latent  heat  of  expansion  may,  by  its  ab- 
sorption and  transformation,  and  the  resulting  transforming  of  internal 
and  external  work,  cause  no  other  effect  than  change  of  volume,  as  e.  g. 
when  air  is  heated;  or  it  may  at  the  same  time  produce  an  alteration 
of  the  solid  to  the  fluid,  or  of  the  liquid  to  the  vaporous  state.  The  spe- 
cific heat  of  constant  volume,  no  molecular  or  other  work  being  done, 
measures  the  heat  untransformed,  and,  as  sensible  he-at  producing  rise 
in  temperature.  The  specific  heat  of  constant  pressure  measures  the 
sum  of  latent  and  sensible  heats,  when  a  gas  is  heated,  and  no  alteration 
of  physical  state  can  occur.  It  usually  is  assumed  to  include  both  in-* 
ternal  and  external  work,  as  well  as  sensible  heat;  but  where  used  in 
an  unaccustomed  sense  the  conditions  of  the  case  are  always  stated. 

The  Latent  Heats  of  Fusion  and  Vaporization: 

The  latent  heats  of  fusion  and  vaporization  measure  the  quantities 
of  heat  transformed  in  these  changes  of  physical  state.  In  the  first  of 
these  two  cases  'the  work  done  is  mainly  internal;  in  the  second  the  in- 
ternal work  performed  is  much  greater,  but  is  next  so  enormously  in  ex- 
cess of  the  amount  of  external  work  done;  and  the  higher  the  pressure 
under  which  vaporization  takes  place,  the  larger  proportionately  the 
measure  of  external  work  and  of  the  heat  demanded  for  its  perform- 
ance. 
Conduction: 

Conduction  is  the  method  of  transfer  of  heat  flow  from  part  to  part 
in  the  same  body,  or  from  one  to  another  of  bodies  in  contact.  These 
phenomena  are  not  precisely  the  same.  The  flow  of  heat  from  a  hot  to 


TECHNICAL  TERMS  17 

a  cold  body  in  contact  depends  not  only  on  the  conducting  power  of  the 
two  substances,  but  also,  and  often  mainly,  on  the  condition  of  the 
touching  surfaces  and  the  perfection  of  their  contact.  The  rate  of  trans- 
fer within  any  given  material  depends  solely  on  the  variation  of  temper- 
ature along  the  line  of  flow,  and  on  the  character  of  the  substance. 

Calorific  Values  of  Fuels: 

The  calorific  value  of  fuel  is  the  amount  of  heat,  expressed  in  ther- 
mal units,  evolved  by  the  complete  combustion  of  a  unit  weight  of  the 
fuel  in  the  oxygen.  These  values  are  determined  by  the  use  of  an  appar- 
atus known  as  the  "Calorimeter". 

«. 

Values  of  Liquid   Fuels: 

It  is  but  natural  that  the  value  of  fuel  differs  with  the  amount  of 
properties  it  contains.  It  should  be  understood  that  the  fuel  question 
of  the  Diesel  engine  is  easier  solvable  than  any  other  type  of  machinery, 
in  particular  the  steam  engine.  It  is  a  fact,  which  has  been  demon- 
strated under  the  most  expert  observation  of  engineers  in  this  country 
as  well  as  in  Europe,  under  different  climatical  conditions,  that  the  Die- 
sel engine  will  consume  the  cheaper  kind  of  oils  with  astonishing  re- 
sults. 

In  many  cases  compounded  oils,  such  as  lard  oil,  vegetable  oils  of 
almost  any  known  kind,  in  fact  any  oil  with  the  flash-point  of  very  low 
degree,  sometimes  intermixed  with  coal  tar,  obtained  of  coal  of  poor 
quality  give  the  greatest  results.  In  other  words,  the  maximum  results 
are  obtained  with  the  minimum  amount  of  fuel  value,  resulting  in  low  ex- 
penditure. To  get  a  clear  conception  of  the  qualities  of  the  usual  known 
kinds  of  solid  liquids,  it  will  be  beneficial  to  study  a  few  ordinary  liquids. 
The  analysis,  as  expressed  in  the  terms  of  the  chemical  language,  is  as 
follows: 

C Carbon 

H Hydrogen 

N Nitrogen 

O Oxygen 

S Sulphur 

A Ash 

Coal   Tar: 

The  value  of  coal  tar  as  a  fuel  is  usually  very  much  lower  than  its 
value  for  other  purposes,  but  as  a  fuel-medium  for  Diesel  engines  it  is 
very  valuable.  The  yield  of  coal  tar  varies  with  the  kind  of  coal  «,nd 
with  the  methods  employed.  From  about  4}4  per  cent  to  6^  per  cent  of 
the  weight  of  coal.  It  is  Lower  in  hydrogen  and  higher  in  carbon  than 
crude  oil,  and  therefore  of  a  lower  calorific  value.  Tar  made  from  stand- 
ard gas  coal  would  have  an  ultimate  analysis  about  as  follows: 


18  TECHNICAL  TERMS 

Carbon    89.21% 

Hydrogen  4.95% 

Nitrogen 0.11% 

Oxygen   4.23% 

Sulphur  0.56% 

Ash Trace 

It  has  specific  gravity  of  about  1.25,  a  gallon  weighing  10.3  pounds. 
Coal  tar  may  be  burned  if  heated  and  strained,  the  same  as  other  liquid 
fuels. 

Oil  Tar: 

Oil  tar  is  produced  in  ordinary  gas  apparatus,  has  a  specific  gravity 
of  1.15,  is  less  sticky  than  coal  tar,  and  can  be  transported,  handled  and 
burned  like  other  oils.  Its  analysis  is  about  as  follows: 

Carbon    92.7  % 

Hydrogen   6.13% 

Nitrogen     0.11% 

Oxygen    0.69% 

Sulphur     0.37% 

Ash    Trace 

It  is  important  that  the  fuel  oil  burned  in  the  Diesel  engine  should 
be  carefully  examined  and  should  be  free  from  incombustible  solids. 
The  oils  should  be  mobile  at  0  degrees  C.,  as  it  is  heavy  and  rather 
viscous,  or  contains  considerable  proportions  of  asphaltum  or  paraffine, 
it  will  become  sluggish  and  stiff  at  low  temperatures  and  considerable 
heat  will  have  to  be  supplied  to  warm  it  before  it  can  be  run  to  the  en- 
gine. 

If  it  is  necessary  to  use  very  heavy  or  viscous  oils  the  engine  should 
first  be  warmed  by  running  on  a  lighter  fuel  oil,  and  the  heavy  oil  intro- 
duced after  the  engine  is  running  well  and  warmed  up.  This  process 
should  be  reversed  in  shutting  down,  in  order  to  wash  the  heavy  oils  out 
of  the  fuel  valves  and  small  passages  and  pipes. 

If  tine  heavy  oil  is  fed  into  the  cylinders  without  first  being  pre- 
heated and  while  the  engine  is  cool,  it  will  tend  to  form  a  deposit  on 
the  cylinder  head,  and  also  will  give  off  petroleum  vapor,  which  requires 
a  greater  amount  of  oxygen  for  combustion  than  what  is  contained  in 
the  volume  of  air  in  the  cylinders. 

For  proper  combustion  the  oil  should  be  free  from  water,  grit  and 
other  solids.  At  least  80%  of  the  oil  should  distill  over  at  350  degrees 
C.  Also  the  oil  should  not  contain  more  than  4  %  of  material  insoluble 
in  xylene!  as  a  large  proportion  of  insoluble  material  will  tend  to  form 
coke  in  the  cylinders. 

The  presence  of  sulphur  in  small  percentages  (1%)  especially  if  the 
oil  be  free  from  water,  is  not  injurious,  but  in  larger  content  will  cause 
corrosion  of  the  working  iparts.  The  best  results  have  been  obtained 
from  California  oils,  if  the  lighter  oils,  such  as  gasoline  and  naptha, 


TECHNICAL  TERMS  19 

which  are  of  a  greater  commercial  value,  have  been  drawn  off  by  dis- 
tilling, and  the  asphaltum  contents  reduced  to  about  20  or  25%.  Of  this 
subject  we  will  later  dwell  on,  as  the  fuel  question  is  of  vital  importance. 

British  Thermal  Units: 

A  British  Thermal  Unit  is  the  amount  of  heat  required  to  raise  the 
temperature  of  one  pound  of  water  one  degree  Fahrenheit,  at  or  about 
39.1  degrees  Fahrenheit,  and  represents  a  mechanical  energy  of  778  foot 
pounds. 

Hydro-Carbons: 

A  chemical  compound,  or  rather  a  chemical  combination  commonly 
found  in  large  percentage  in  petroleum  and  coal-tar  as  well  as  practi- 
cally all  our  vegetable  oils,  composed  of  hydro-carbons  or  compounds 
closely  related  thereto. 

The  Composition  of  Water: 

,  Water  is  a  neutral  compound,  exhibiting,  when  pure,  neither  acid 
nor  alkaline  reaction;  but  so  freely  does  it  dissolve  substances  with 
which  it  is  brought  in  contact,  that  it  is  rarely  found  in  nature  abso- 
lutely free  from  either  acidity  or  alkalinity.  Its  presence  is  essential 
to  nearly  all  the  chemical  operations  of  nature,  as  well  <as  in  the  arti- 
ficial product  of  solid  liquids. 

The  fluid  may  be  decomposed  in  either  of  several  ways,  as  by  heat 
alone,  a  process  of  "dissociation"  of  its  elements  taken  place  at  between 
2000  degrees  and  4000  degrees  Fahr.  (1100  degrees  to  2200  degrees  C.) 
or  by  voltaic  current,  and  by  the  action  of  various  metals  or  metalloids 
at  high  temperatures,  when  the  substance  employed  has  a  strong  affinity 
for  the  oxygen,  as  have  carbon,  iron,  etc. 

Water  is  found  wherever  hydrogen  is  burned,  in  air  or  oxygen,  either 
alone  or  in  combination  with  other  elements.  It  enters  into  combination 
with  many  other  substances  and  as  water  of  crystalization,  for  example, 
often  influences  the  character  of  the  compound  to  a  very  important  de- 
gree. 

Composition  of  Sea  Water: 

Sea  water  is  a  mineral  water,  strongly  saline,  considerably  chlori- 
nated, and  slightly  alkaline.  The  composition  of  the  water  of  the  ocean 
differs  very  slightly  in  different  localities.  It  contains  about  1/32  of  its 
own  weight  of  salts,  mainly  common  salt,  with  various  other  chlorides 
and  bromides,  and  some  gases.  Deposits  from  sea  water  and  from  any 
other  water  containing  solid  matter  either  in  solution  or  suspended,  will 
always  occur  on  evaporating  the  water;  and  these  deposits  form  the 
incrustation  and  sediment  which  endanger  the  passageways,  or  com- 
monly known  as  water-jacketing,  on  Diesel  engines,  and  may  lead  to  ser- 
ious consequences  when  not  properly  attended  to. 


CHAPTER  II. 


THEORY 

GAS 

A  gas  is  a  substance  whose  molecules  are  repellent  to  each  other, 
or  in  other  words,  has  a  tendency  to  separate. 

When  a  quantity  of  gas  has  definite  pressure  and  volume  at  a  certain 
temperature,  it  is  said  to  be  in  a  certain  state.  Now  if  any  outside  agent 
should  affect  the  gas  in  such  a  manner  as  to  change  the  pressure,  vol- 
ume or  temperature,  it  is  said  to  undergo  a  change  of  state. 

Suppose  a  cylinder  is  fitted  with  an  air-tight  piston,  which  is  forced 
down  quickly,  compressing  the  air,  the  work  done  by  the  piston  in  com- 
pression is  given  off  .to  the  gas  in  the  form  of  heat,  consequently  the 
temperature  will  rise  in  proportion  to  the  pressure  exerted  on  it,  which 
change  of  state  is  known  as  adiabatic  compression. 

Then  adiabatic  expansion  and  compression  is  when  the  tempera- 
ture of  gas  changes  as  the  volume  increases  or  decreases. 

If  in  the  same  cylinder  the  piston  were  pushed  down  very  slowly  al- 
lowing the  heat  to  pas's  through  the  cylinder  wall  as  soon  as  forced,  the 
temperature  on  the  inside  would  be  the  same  as  that  on  the  outside,  and 
would  be  known  as  isothermal  expansion. 

Then  isothermal  expansion  or  compression  is  the  increase  or  de- 
crease of  a  volume  of  gas  by  compression  or  expansion  without  produc- 
ing a  change  in  temperature. 

In  the  accompanying  diagram  (figure  a)  let  the  axis  of  volume  B 
represent  cubic  feet  of  gas  and  axis  of  pressure  A  represent  the  pressure 
per  cubic  foot;  suppose  you  had  10  cubic  feet  of  gas  at  a 
pressure  of  10  pounds  absolute  and  compressed  it  to  8  cubic  feet;  the 
product  of  the  pressure  and  volume  would  be  10  x  10=100;  as  it  is  com- 
pressed isothermially  the  product  of  the  pressure  and  volume  must  re- 
main unchanged,  consequently  100  -=-  8  —  I2y2  pounds.  If  we  compress 
the  gas  to  6  cubic  feet  we  would  have  10  X  10  =  100;  100  -=-  6  =  16% 
pounds. 

If  compressed  to  4  cubic  feet  we  would  have  10  X  10  -r-  4  =  25  pounds, 
and  if  compressed  to  2  cubic  feet  it  would  equal  10  X  10  -f-  2=50  pounds, 
etc.  If  the  2  cubic  feet  of  air  was  expanded  back  to  the  10  cubic  feet 
and  heat  were  added  to  the  air  to  keep  it  at  the  same  temperature,  it 
will  pass  through  the  same  stages  on  the  curved  line  as  it  did  in  com- 
pression. 


THPJORY 


21 


Figure  (a). 
Demonstration  of  Isothermal  Expansion 


In  practical  work  on  Die- 
sel engines,  ammonia  com- 
pressors, etc.,  we  have  to 
deal  with  adiabatic  expansion 
and  our  compression  which 
not  only  contains  the  in- 
crease of  pressure  to  the  de- 
crease of  volume,  but  an  ad- 
ditional pressure  caused  by 
the  increase  of  temperature 
which  makes  it  a  little  more 
difficult  to  figure.  If  no  heat 
were  lost  through  cylinder 
walls,  leaks,  etc.,  constant 
1.405  could  be  uised,  giving  an 
accurate  pressure  at  any 
stage  of  the  compression,  but 
as  engines  differ  considerably 
in  heat  lost  only  an  approx- 
imate constant  can  be  given, 

which  is  1.26.     In  nearly  all  experiments  on  gas  and  oil  engines  it  has 
given  satisfactory  results. 

We  will  suppose  we  have  10  cubic  feet  of  air  in  diagram  (b)  under 
a  10  pound  pressure,  then  we  compress  it  to  8  cubic  feet;  now  we  have 
pounds  pressure  plus  an  additional   pressure  caused  by  the    heat 

of  compression,  consequently  log- 
arithm must  be  used  to  find  the 
value  of  the  constant,  which  is  PV 
1.26  (P=pressure  V=volume)  then 
log  P=l  + 1.26=2. 26  log  of  press- 
ure, then  log  10=1;  1X2.26=2.26, 
log  of  constant;  constant  is  182. 
Then  the  'product  of  volume  of  gas 
and  pressure  must  equal  182.  Now 
if  the  volume  is  compressed  to  8 
cubic  feet  and  if  V  1.26  equals  182; 
PX8  1:26,  then  log  182=2.26007— 
1. 26 X. 90309=1.13789  or  log  of  pres- 
sure, then  P=13.73  pounds.  If  the 
volume  is  compressed  to  6  cubic 
feet  we  have  constant  182 — (6) 
1.26  or  log  182=2.26007—1.26  X 


.77815=1.27961     log     of     pressure; 
then  P=18.6  pounds.  If  compressed 
Figure  (&).  to  4  cubic  feet  it  would  be  log  182 

Demonstration  of  Adiabatic  =2.26007—1.26  (log  4)  or  2.26007— 

Expansion.  1.26   X   .60216=1.50148  log  of  pres- 

sure; then  P=31.74  pounds.     If  compressed  to  2  cubic  feet  the  pressure 


22 


THEORY 


would  be  log  182=2.26007—1.26  x  .30103=1.88078  log  of  pressure-    then 
P=75.96  pounds,  etc. 


8     2 


The  only  way  to  find  the  action  and  pressure  of  gas  in  the  cylinder 
is  to  attach  an  instrument  to  it,  called  the  indicator,  and  take  an  indica- 
tor card,  which  records  the  pressure  on  the  piston  at  all  points  in  the 
cylinder. 


THEORY 


23 


Suppose  in  figure  (c)  'that  ignition  takes  place  when  the  pressure 
reaches  100  pounds  and  rises  to  200  pounds,  as  the  piston  passes  dead 
center  on  its  working  stroke  the  gas  continues  to  burn  until  the  piston 
is  half  way  to  ordinate  2,  at  which  point  combustion  has  been  com- 
pleted and  the  pressure  gradually  decreases  until  it  reaches  the  point  A, 
then  the  exhaust  valve  opens  and  the  piston  on  its  return  stroke  (see 
exhaust  line  on  diagram)  forced  the  burnt  gases  out;  as  the  piston 
moves  downward  on  the  second  revolution  a  new  charge  of  gas  is  drawn 
in  (see  suction  line  on  diagram)  forces  the  burned  gases  out;  as  the 
piston  moves  downward  on  the  second  revolution  a  new  charge  of  gas 
is  drawn  in  (see  suction  line  on  diagram) ;  then  on  the  return  stroke 
the  fresh  charge  is  compressed  (see  compression  line  on  diagram)  to  100 
pounds  at  which  place  it  is  ignited  again. 

A  little  study  of  the  above  diagram  will  give  the  reader  a  good  idea 
of  the  relation  that  exists  between  the  indicator  card  and  the  pressure 
acting  on  the  piston  in  the  cylinder. 

Suppose  AB  represents  the  axis  of  pressure  and  BC  represents  the 
axis  volume  of  cylinder,  then  any  distance  measured  from  AB  in  the 
direction  and  parallel  with  BC  is  the  abscissa  of  that  point  and  all  the 
lines  starting  from  axis  BC  and  parallel  with  axis  AB  are  known  as  the 
ordinates. 

To  make  it  more  clear  consider  distance  P  as  clearance  volume,  to 
the  same  scale  as  that  of  L,  which  represents  cylinder  volume.  The 
axis  BC  may  either  represent  atmospheric  pressure  or  line  of  no  press- 
ure, that  is,  absolute  vacuum,  usually  iBC  will  represent  atmospheric 
pressure. 

In  figure  (d)  the  ab- 
scissa of  the  point  is  xl, 
and  the  ordinate  of  the 
point  is  1"  1,  then  the  or- 
dinate and  abscissa  of  1 
are  1"  1  and  x  1  respect- 
ively, of  2  are  2"  2  and  x 
2,  etc. 

The  line  yv  represents 
the  expansion  of  the  gas, 
or  in  other  words  the 
pressure  per  square  inch 
acting  on  the  area  of  the 
piston  throughout  the  full 
stroke  (the  diameter  L). 

When  ignition  takes  place  the  pressure  acting  on  piston  is  equal  to  tp 
yw  pounds;  as  the  piston  moves  forward  to  line  1"  1  the  pressure  on 
the  area  of  the  piston  has  decreased  to  x  1  pounds,  etc.,  until  piston 
reaches  end  of  stroke  at  v  and  exhaust  escapes  from  cylinder,  conse- 
quently the  amount  of  work  performed  is  equal  to  the  number  of  pounds 
pressure  acting  on  the  area  of  piston  throuigh.  the  full  length  of  stroke. 
In  order  to  find  the  area  of  indicator  card  it  is  necessary  to  divide  it 


Figure  (d). 

Demonstrating  Expansion  of  Gases 
in  Cylinder. 


THEORY 


into  a  number  of  ordinates  as  shown  in  figure  (d)  which  are  9,  then  add 
the  length  of  all  of  them  together  and  divide  by  number  of  lines,  this 
will  give  the  average  heights  of  the  diagram  which  is  called  mean  ordi- 
nates, then  multiply  the  mean  ordinate  by  the  length  of  stroke  (distance 
L),  this  will  give  the  mean  effective  pressure  (abbreviated  to  M.  E.  P.) 
acting  on  the  working  stroke,  but  as  a  small  amount  of  the  power  given 
off  in  the  working  stroke,  will  be  consumed  in  compressing  the  new 
charge  of  gas  in  the  return  stroke,  therefore  it  will  be  necessary  to  sub- 
tract the  area  of  compression  from  the  area  of  expansion,  in  order  to 
find  the  effective  foot  pounds  of  work  performed  in  one  cycle.  The  area 
of  compression  is  found  by  the  same  method  as  in  expansion  asi  follows : 
Ordinate  y'w,  1'  1",  2'  2",  etc.,  divide  by  the  number  of  measurements 
taken  and  multiply  by  x"  6  (length  of  compression),  which  will  give 
the  power  lost  in  compression. 

In  figure  (d)  we  will  suppose  that  ignition  took  place  when  the 
pressure  reached  450  pounds;  (the  piston  would  almost  be  on  dead  cen- 
ter) the  explosion  causing  the  pressure  to  raise  to  a  little  more  than  550 
pounds  before  the  piston  started  downward  on  the  working  stroke,  as 
the  piston  moved  downward  the  decrease  of  pressure  is  recorded  on  the 
indicator  card  until  the  exhaust  valve  is  opened  and  the  pressure  inside 
the  cylinder  equalizes  with  the  atmospheric  pressure  on  the  outside. 
Then  we  take  the  card  and  find  the  length  of  ordinates  as  described  in 
figure  (d),  which  are  13  10-16  inches,  changing  13  10-16  inches  to  16th., 
we  would  have  16  X  13  +  10  or  218  sixteenths,  which  is  the  length  of 
the  12  ordinates;  then  218  -:-  12  =  18%  sixteenth,  or  the  average  height 
of  1  ordinate. 

If  2  10-16  inches  =  600 
(the  scale  of  pounds  is 
found  by  the  number  of 
springs  used) ;  1/16  =  600 
-r-  42  or  14  2/3  pounds, 
then  18%  X  14%  =  266 
4/9  pounds  to  the  square 
inch  acting  on  area  of  pis- 
ton throughout  the  full 
stroke,  which  is  12  inches 
—then  12  x  266  4/9  = 
3197%  inch  pounds  of 
work  performed;  now  we 
measure  the  mean  ordi- 
nates of  the  compression, 
Figure  (e).  which  are  4  inches;  then 
Practical  Demonstration  of  Indicator  Card.  4  _,_  8  __  y  incn length 

of  mean  ordinate;  then  y2  X  16  or  8  sixteenths.  8  X  14%  =  117% 
pounds.  Therefore  the  compression  averages  117%  pounds  to  the  square 
inch  for  8  inches;  then  8  X  117%  —  933%  inch  pounds  of  work  per- 
formed in  compression.  Then  3197% — 9332%  =  2263%  inch  pounds  of 


GOO 


4C6 

3*0 

3*0 
WO 


1*0 


\ 


THEORY 


25 


effective  work  performed  in  one  cycle.  In  order  to  find  the  M.  E.  P.  we 
divide  2263%  by  the  length  of  stroke  in  inches  or  2263%  -~  12  =  188.63 
pounds. 

NOTE — Some  figures  may  be  eliminated  by  subtracting  the  area  of 
compression  from  area  of  expansion  and  dividing  by  length  of  stroke, 
which  will  give  the  measurement  for  the  scale  of  pounds. 


PROPER    MANAGEMENT   AND    NECESSARY    PRECAUTIONS    IN 
USING  THE  INDICATOR 

(1)  Before  using  the  indicator  give  it  a  proper  inspection.    Ascer- 
tain the  condition  of  the  indicator.  Any  defective  valve  or  leaky  mechan- 
ical contrivance  sihould  be  remedied  before  using  the  same. 

(2)  Add  a  small  quantity  of  oil  in  drum  spindle  and  piston.     Use 
only  mineral  oil.    Oil  of  heavy  viscosity  should  never  be  used.    It  causes 
gumming  and  the  result  will  be  a  retarding  of  the  instrument  with  con- 
sequently bad  results. 

(3)  The  advisability  of  properly  rigging  the  instrument  to  the  en- 
gine cannot  be  overestimated.    Previous  to  operating  the  engine  obtain 
the  correct  length  of  cord. 


Practical  Application  of  Indicator, 


26  THEORY 

(4)  While   engine   is   being   operated   with  attached   cylinder   never 
alter  any  parts  on  indicator  parts.   It  may  result  in  improper  termination 
of  Cards.  .     , 

(5)  The  paper  on  the  drum  must  be  properly  placed.    See  that  the 
paper  clips  are  working  perfectly. 

(6)  The  pencil  should  be  fairly  sharp  and  brought  to  bear  against 
the  card  very  lightly. 

(7)  Any  assembling  of  saturation  inside   the  instrument  should  be 
avoided. 

(8)  When  using  Thompson  Indicator  be  sure  that  the  three-way  cock 
has  the  proper  amount  of  opening.   Any  throttling  of  power  may  have  the 
result  of  imperfect  recording. 


MEASUREMENT   OF    INDICATED   HORSE-POWER   WITH    THE 

INDICATOR 

The  indicated  horse-power,  or  the  rate  at  which  an  engine  receives 
mechanical  energy,  is  measured  by  the  mechanical  energy  imparted  to 
the  piston  per  minute  in  foot-pounds,  divided  by  33,000. 

The  work  done  iper  stroke  of  L  feet  by  the  pressure  on  a  piston 
whose  area  is  A  square  inches  is 

p  A  L  foot-pounds, 

p  being  the  mean   effective   pressure  per  square   inch  in   pounds   upon 
the  piston. 

If  N  is  the  number  of  power  strokes  per  minute,  i.  e.,  the  number 
of  strokes  of  'the  piston  when  the  driving  pressure  p  is  acting,  then  the 
indicated  horsepower  = 

I.  H.  P.— P  LAN 


33,000 

This  may  be  applied  to  every  cylinder  when  the  engine  is  working 
uniformly. 

The  quantity  N  in  the  above  formula  miay  be  obtained  by  some 
form  of  tachometer  or  by  >some  form  of  a  counter. 

The  area  of  the  piston  is  best  obtained  by  removing  the  cylinder 
cover  and  measuring  the  diameter  of  the  cylinder  with  a  micrometer 
gauge. 

It  is  necessary  to  measure  the  diameter  of  the  cylinder  and  piston 
rod  at  a  number  of  -positions,  and  take  the  mean  of  each  of  them,  as 
these  often  wear  out  of  truth. 

The  length  of  the  stroke  can  be  obtained  by  marking  the  cross- 
head  guide  at  the  extreme  ends  of  the  stroke. 

The  mean  effective  pressure  is  obtained  from  the  indicator  diagram. 
A  comparison  of  previously  taken  indicator  cards  of  the  engine  will  give 


THEORY  27 

accurate  performance  of  mechanism  and  determine  faulty  operation.  In 
other  pages  of  this  book  a  thorough  explanation  is  given  as  to  the  meas- 
urement requirement  properly  ascertaining  the  function  of  the  engine. 


DEFINITION    OF   "CARNOT"    AND   "OTTO"    CYCLE 

The  definition  of  cycle  may  be  used  to  indicate  a  period  of  time  in 
which  a  series  of  events  repeat  themselves;  a,  recurring  series  of  events 
or  a  series  of  operations  terminating  to  its  original  state. 

In  the  Cannot  cycle  its  operation  performed  by  perfect  gas  under 
perfect  mechanical  efficiency  proves  that  thermodynamic — heat  con- 
verted into  mechanical  work — efficiency  of  this  engine  is  the  'highest 
that  can  be  obtained  by  the  use  of  any  substance  or  combinations  of  sub- 
stances in  any  engine  working  in  any  other  cycle  between  the  identical 
limits  of  existing  temperature. 

The  practical  engine  as  it  improves  approaches  this  efficiency,  but 
can  never  attain  it.  In  other  words,  the  nearer  the  efficiency  of  any 
heat  engine  is  to  that  of  the  Carnot  cycle  efficiency,  the  nearer  it  is  to 
its  highest  attainable  limit  of  perfection. 

As  will  be  seen  in  the  subject  dealing  with  the  isothermal  and  adi- 
abatic  expansion,  the  heat  unust  be  lowered  by  an  adiabatic  expansion  in 
which  the  heat  that  disappears  does  so  in  doing  its  mechanical  work. 
We  begin  to  realize  that  the  compression  temperature  on  a  Diesel  en- 
gine acting  adiabatically,  in  order  that  the  heat  received  as  heat  may  be 
received  at  the  highest  possible  temperature  making  it  possible  to  ac- 
complish the  desired  results. 

In  theory  internal  combustion  engines  work  on  either  of  the  Otto 
or  the  Carnot  cycle.  In  defining  this  theory  in  the  laws  of  thermodynam- 
ics alluding  to  internal  combustion  engines,  we  must  first  understand 
that  all  engines  used  for  generation  of  power  are  heat  engines. 

To  establish  an  ideal  standard  of  comparison  in  different  types  fol- 
lowing exclusive  processes  of  operation  the  term  cycle  is  applied.  When 
giving  this  subject  a  little  thought  we  soon  conclude  that  the  cycle  of 
operation,  as  the  indicator  application  wall  convince  us,  is  distinctly  dif- 
ferent from  that  of  the  Diesel. 

The  Diesel  engine,  which  is  a  "constant  pressure"  engine,  or  to  be 
plain,  in  which  all  the  heat  is  token  to  generate  its  power  while  the 
pressure  remains  "constant"  in  the  cylinder  and  its  rejection  occurs  in 
identical  condition,  follows  an  exclusive  "Diesel"  cycle  peculiar  to  this 
engine. 

In  contrast  to  this  constant  pressure  cycle  we  have  the  "constant 
volume"  cycle,  which  we  pleased  to  call  the  "Otto"  cycle.  In  the  study 
of  Diesel  engineering  we  find  that  this  constant  volume  only  exists  in 
the  gas  or  gasoline  driven  engine,  where  a  constant  volume  establishes 
the  "volumetric  efficiency"  of  the  engine.  This  volumetric  efficiency  is 
the  fundamental  principle  of  operation  determining  the  results  of  power 
production  of  the  engine  itself. 


28  THEORY 

HEAT 

All  bodies  are  supposed  to  be  composed  of  minute  particles — so 
small  that  they  can  scarcely  be  seen  by  a  high  powered  microscope,  they 
are  called  molecules.  These  molecules  have  weight  and  motion;  in  fact, 
the  energy  that  any  body  possesses  is  due  to  the  rapidity  thait  these  mole- 
cules vibrate  to  and  fro.  The  state  of  any  substance  whether  gaseous, 
liquid  or  solid,  is  determined  by  the  attraction  that  these  molecules  have 
for  each  other,  as  follows: 

In  a  gas,  the  molecules  are  said  to  be  repellent  to  each  other,  that 
is,  their  adhesive  qualities  are  entirely  suspended,  which  causes  them 
to  travel  away  from  one  another  in  the  direction  of  least  resistance, 
thereby  producing  a  state  known  as  expansion — there  is  no  limit  to  the 
expansion  of  an  unconfined  gas. 

In  a  liquid  body  the  adhesive  qualities  are  only  a  slight  degree 
greater  than  the  cohesive  qualities,  thereby  creating  a  state  that  per- 
mits the  molecules  to  pass  freely  over  or  under  one  another  in  any  di- 
rection, which  acting  with  the  laws  of  gravity,  causes  them  to  seek  the 
lowest  possible  level.  A  liquid  has  no  definite  shape  of  its  own,  but  as- 
sumes the  .shape  of  the  object  in  which  it  resits. 

In  a  solid  the  adhesive  qualities  are  great  enough  to  overcome  the 
cohesive  qualities  to  the  extent  of  causing  the  mass  to  assume  a  defi- 
nite size  and  shape,  thereby  forcing  the  molecules  to  remain  in  a  fixed 
path  of  motion.  A  force  of  more  or  less  degree  is  required  to  cause  a 
solid  to  change  its  shape. 

The  vibratory  motion  of  these  bodies  determines  how  hot  or  how 
cold  the  body  is,  for  example: 

When  a  liquid  boils,  it  is  the  maximum  stage  of  motion  for  the 
molecules  and  they  separate  from  the  main  body  of  liquid  and  pass  off 
into  the  air  in  the  form  of  vapor  or  gas. 

If  you  take  a  piece  of  iron  and  apply  enough  heat  the  molecules  will 
move  so  rapidly  that  they  travel  outside  of  their  fixed  path  of  motion, 
losing  their  attraction  for  each  other.  Consequently  the  molecules  will 
seek  the  lowest  level,  at  which  state  it  is  said  to  be  melted. 

On  the  other  hand,  if  we  should  extract  enough  heat  from  a  gas 
the  molecules  would  lose  sufficient  motion  and  condense  into  a  liquid. 
If  we  continued  to  extract  heat  it  would  finally  become  a  solid,  such  as 
ice,  and  as  we  abstracted  heat  the  motion  of  the  molecules  would  be- 
come less  until  they  came  to  a  state  of  rest,  which  would  be  460  degrees 
below  zero  (Fahrenheit).  So  far  this  has  been  impossible,  the  lowest 
known  temperature  on  record  being  in  the  neighborhood  of  400  degrees 
below  zero  (Fahrenheit). 

It  can  be  readily  seen  that  the  temperature  of  any  body  is  only  a 
measurement  of  motion  of  the  molecule.  These  measurements  are  taken 
by  an  instrument  called  a  thermometer. 


THEORY  29 

COMBUSTION 

In  the  diagrams  a,  b,  c,  d,  and  e  are  pressures  taken  on  a  card  by 
an  instrument  used  for  finding  the  effects  of  different  mixtures  of  gas 
and  air,  when  ignited  in  a  cylinder  at  atmospheric  pressure,  that  is,  ig- 
nition taken  place  at  the  lower  left  hand  corner  and  the  pressure  raises 
in  proportion  to  the  mixture  of  air  and  gas,  which  may  be  summed  up 
as  follows: 

Diagram  (a)     (b)     (c)     (d)     (e) 

Volume   of   air  to   1  volume   of  gas    13      11       9        7        5 

Time   of   explosion:    Second   .28     .18     .13     .07     .05 

Guage  pressure.    Pounds  per  sq.  in  52      63      69      89      96 

In  the  table  as  shown  here  it  can  be  seen  that  a  mixture  5  of  air 
to  1  of  coal  gas  gives  the  best  results.  If  we  were  to  use  4  of  air  to  1  of 
gas  the  pressure  would  be  less  as  there  would  not  be  sufficient  oxygen 
to  complete  combustion,  consequently  the  elements  of  gas  control  the 
amount  of  air  to  be  used.  Experiments  have  proven  that  one  volume  of 


Experiments  of  Coal — Gas  and  Air. 

air  well  saturated  with  gasoline  mixed  with  6  to  9  volumes  of  free  air 
(depending  upon  the  grade  of  gasoline)  gives  the  greatest  mean  effective 
pressure. 

All  fuel  oils  and  gases  contain  hydrogen  and  carbon,  and  are  known 
as  hydrocarbons,  which  when  mixed  with  oxygen  and  burned  the  hydro- 
gen and  carbon  seperate  and  unite  with  the  oxygen,  forming  water  (H2O) 
and  carbon  dioxide  (CO0).  If  the  carbon  unites  with  only  one  part  oxygen 
it  forms  another  substance  known  as  carbon  monoxide. 

The  products  of  combustion  are  oxygen,  carbon  and  hydrogen,  com- 
bined with  one  part  oxygen  forms  water. 

The  elements  with  their  atomic  weights  usually  found  in  fuel  are 
as  follows: 


Elements: 
Hydrogen 
Oxygen 
Nitrogen 
Carbon 
Sulphur 


H.. 
0_ 

N.. 
C.. 

s. 


Atomic  Weight 

1 

16 

14 

12 

_  32 


30  THEORY 

In  the  above  table  we  find  that  the  atomic  weight  of  carbon  is  12 
and  the  atomic  weight  of  oxygen  is  16,  then  in  carbon  dioxide  (COo) 
we  have  by  weight  12  parts  of  carbon  to  32  part  of  oxygen.  In  other 
words  it  requires  32  -:--  12  or  2%  pounds  of  oxygen  to  one  pound  of  car- 
bon. As  only  23%  of  the  air,  by  weight,  is  oxygen,  we  have  2%  -f-  .23 
or  16.6  pounds  of  air  to  supply  the  2%  pounds  of  oxygen,  which  may  be 
summed  up  as  follows, 

1  C   +   11.6  air  —  12.6  pounds  Mixture 

T2.67  01 

1  C    +  ^  ^  — -  12.6    pounds   Elements 

\8.93  N 

fl  C       1 

Carb.  diox.^  I  -f-  8.93  N  —  12.6  pounds Products  of  Combustion 

\2.67  0  J 

In  the  above  table  1  pound  of  C  requires  11.6  pounds  of  air  for  com- 
bustion. The  2.67  pounds  of  O  in  the  11.6  pounds  of  air  combines  with 
the  1  pound  of  carbon  forming  3.67  pounds  of  COo  and  the  8.93  pounds 
of  N  pass  off  with  the)  COo  without  taking  any  part  in  the  combustion. 

In  hydrogen  the  product  of  combustion  is  H  (O,  by  weight  it  is  com- 
posed of  2  parts  of  H  to  16  parts  of  O,  then  1C  -f-  2  =  8  pounds  of  oxy- 
gen to  unite  with  2  pounds  of  hydrogen.  As  oxygen  by  weight  equals 
23%  of  the  air,  we  have  8  -=-  .23  or  34.8  pounds  of  air  to  burn  2  pounds 
of  hydrogen,  which  is  summed  up  as  follows: 

2  H  -f-  34.8  air  =  36.8  pounds Mixture 


2H-}-^  V—  36.8   pounds   Elements 

^26.8  N  r 

(\     TT         "^ 

L   +  26.8  —  36.8  pounds—Products  of  'Combustion 

8  O    J 

Suppose  there  wasn't  sufficient  oxygen  to  unite  with  the  carbon  to 
form  complete  combustion,  then  we  have  as  stated  before  CO  instead 
of  CO2,  that  is,  by  weight  12  parts  of  carbon  to  16  parts  of  oxygen  or 
16  -f-  12  =  1%  pounds  of  oxygen  to  1  pound  of  carbon,  which  is  summed 
up  as  follows: 

1  C  -f  5.8   air  =  6.8   pounds   Mixture 

fl.33  O  1 
1C+  -<  I  =  6.8   pounds   Elements 


I1'330  1=6, 

[4.47N  J 


{1C      ~1 
I    +  4.47  —  6.8  pounds__Produc:ts  of  Combustion 
1.33  O  J 

It  is  not  customary  to  use  the"  weight  of  gas  in  calculating  the  pounds 
of  air  required  for  combustion  in  gas  engines,  as  gas  is  invariably  meas- 


THEORY  31 

ured  in  cubic  feet,  making  it  necessary  ito  figure  air  by  cubic  feet,  which 
may  be  explained  as  follows: 

The  combustible  products  of  hydrocarbons  are  OO2  and  HoO.  It 
is  evident  that  in  each  molecule  of  COo  it  requires  two  atoms  of  oxygen 
to  complete  the  combustion  of  1  atom  of  carbon  and  for  every  molecule 
of  HoO  it  would  repuire  y2  atom  of  oxygen  to  complete  combustion  for 

1  atom  of  hydrogen,    which    may    be    expressed    in    the    formular    of 

H 

2  C  H —  =  number  of  atoms  of  oxygen  required  to  burn  any  hydrocarbon. 

2 

In  chemical  theory  a  gas  requires  y2  as  many  volumes  of  oxygen 
as  there  are  atoms  of  oxygen  in  the  compound.  Then  the  volume  of 
oxygen  required  for  complete  combustion  for  any  hydrocarbon  may  be 
found  in  the  following  formula: 

H  H 

2C+  •--  =(CH )   4.76 

2  4 


As  only  21%  of  air  by  volume  is  oxygen,  we  would  have  1  —  .21  or 
4.76.  The  volume  necessary  for  complete  combustion  of  1  volume  of 
hydrocarbon,  consequently  we  have:  Volume  =  (C  +  H)  4.76. 

4 
Example: 

How  many  cubic  feet  of  air  would  be  required  to  burn  one  cubic  foot 
of  Hexane  (C0H14)? 

Solution: 

H  14 

V  =  (C  +  -    — )  4.76  or  V  =  (6  +  -    — )  4.76 
4  4 

then  V  =  9.5  X  4.76  or  45.2  cubic  feet  of  air. 

To  find  the  volume  of  air  required  for  a  gas  containing  a  mixture 
of  various  hydrocarbons,  use  the  above  formula  for  each  constituent  of 
the  gas  and  multiply  the  results  by  the  percent  and  add  together. 

Example: 

How  many  cubic  feet  of  air  would  be  required  to  burn  gas  composed 
of  the  following? 

Constituents  of  Gas: 

Propane  C-H   15% 

Methane   C  H*   75% 

Butane    C  H       10% 


32  THEORY 

Solution : 

8 

V  =  (3  +  -    — )  4.76  or  V  =  5  X  4.76  =  23.8  cu.  ft.  of  air 
4 

4 

V  —  (1  +  -    — )  4.76  or  V  =  2  x  4.76  =    9.52  cu.  ft.  of  air 
4 

10 

V  =  (4  +  -    — )  4.76  or  V  —  6.5  x  4.76  —  30.94  cu.  ft.  of  air 
4 


Then 


Propane  =  23.8  X  .15  =  3.57  cu.  ft.  of  air 
Methane  =  9.52  X  .75  =  7.14  cu.  ft.  of  air 
Butane  =  30.94  X  .10  =  3.09  cu.  ft.  of  air 

Total  _  __13.8  cu.  ft.  of  air.    Answer. 


RELATIVE  WEIGHTS  OF  ELEMENTS 

The  usual  weight  definition  of  the  atoms  or  the  atomic  weights  of 
the  elements  are  expressed  in  terms  of  the  weight  of  an  atom  of  hydro- 
gen. Thus  H  =  1,  O  =  16,  N  =  14,  C  =  12,  and  S  —  32. 

Since  equal  volumes  of  gases  contain  the  same  number  of  molecules 
it  follows  that  the  approximate  weights  of  equal  volumes  of  gases  will 
be  the  same  as  the  relative  weights  of  their  molecules. 


TABLE  OF  RELATIVE  ATOMIC  AND  MOLECULAR  WEIGHT 

Hydrogen     Atomic   Weight  Molecular  Weight 

Oxygen H  —    1  H.(—    1X2  =2 

Nitrogen   O  =  16  O.~  =  16  X  2  =32 

Carbon     N  =  14  N~o  =  14  X  2  =28 

Sulphur   C   =  12 

Element  or  Compound  S  =  32 


COMPOSITION   OF  AIR 

For  an   approximate  combustion   calculation   the   composition   of   at- 
mospheric air  may  be  taken  as  follows: 

Oxygen 23  per  cent 21  per  cent 

Nitrogen 77  per  cent ; 79  per  cent 


THEORY  33 

APPROXIMATE    CALORIFIC    VALUES    OF    THE    COMMON 
COMBUSTIBLES 

Heat  Evolved  per 

Combustible  Product  of  Combustible         Lb.  of  Combustible 

B.  T.  U. 

Carbon    (C)    Carbon  Monoxide   (CO)   4,450 

Carbon    (C)    Carbon  Dioxide   (CO2)    14,540 

Hydrogen    (H)    Waiter  (H2O)   62,030 

Sulphur    (S)    Sulphur   (S)    '    4,050 

Carbon  Monoxide   (CO)— Carbon  Dioxide    (OOo) 4,300 

Ethylene  (CoH4) Carbon  Dioxide  (COo)  and  Water  (H2O)  21,500 

Methane    (CH4)    Carbon  Dioxide  (CO.")  and  Water  (H^O)  23,550 


SOME  FACTS  ON   COMBUSTIBLE  SUBSTANCES 

The  principal  components  of  liquid  fuels  are  carbon,  hydrogen,  oxy- 
gen and  nitrogen. 

Oxygen  does  not  burn,  but  it  is  a  supporter  of  combustion. 

The  pressure  of  liquid  at  any  point  is  equal  in  all  directions. 

There  is  an  equal  number  of  molecules  in  equal  volumes  of  all  gases 
at  the  same  temperature  and  pressure. 

Nitrogen  will  neither  burn  nor  support  combustion. 

Water  vapor,  if  present  in  large  quantities,  retards  ignition  and  the 
propagation  of  explosion.  Before  an  explosion  can  occur,  or  combus- 
tion, the  vapor  must  be  raised  to  the  ignition  temperature  of  the  gas  and 
on  account  of  the  high  specific  heat  of  water,  considerable  heat  is  thus 
absorbed. 

The  boiling  point  rises  with  increase  of  pressure  and  falls  with  de- 
crease of  pressure. 

A  cubic  foot  of  dry  air  at  32°  F.  at  sea  level  weighs  0.080728  Ib. 

Absolute  zero  is  — 459.4;  above  this  temperature  everything  scienti- 
fically contains  heat. 

The  density  of  a  body  depends  both  upon  its  mass  and  its  volume. 

Water  is  reduced  only  0.00005  of  its  volume  by  a  pressure  of  one 
atmosphere.  A  gas  is  reduced  to  one-half  its  volume  by  the  same 
pressure. 

Gases  have  no  elastic  limit.  No  amount  of  compression  can  per- 
manently change  their  polume;  they  always  return  to  their  original  vol- 
ume when  the  distorting  pressure  is  removed. 

Velocity  is  the  rate  of  motion. 

Specific  gravity  is  the  given  amount  of  water  at  60  degree  normal 
temperature.  Other  substances  might  be  selected,  but  the  most  suitable 
standard  is  water,  therefore  it  is  used  for  the  purpose  of  determining  the 
density  of  solids  and  liquids, 


34  THEORY 

The  British  Thermal  Unit  (B.T.U.)  is  a  unit  to  measure  the  quan- 
tity of  heat  generated  by  the  burning  of  substances.  It  is  equivalent  to 
the  amount  of  heat  required  to  raise  the  temperature  of  1  Ib.  of  water 
1  degree  of  the  Fahrenheit  scale,  or  1  B.T.U.  is  equivalent  to  778  foot- 
pounds. 

When  heat  is  added  to  a  body,  whether  solid,  liquid  or  gaseous,  the 
vibration  of  the  molecules  composing  the  body  increases. 

The  centigrade  scale  differs  from  the  Fahrenheit  in  making  the 
freezing  point  0°  and  the  boiling  point  100°,  the  space  between  being 
divided  into  100  equal  parts.  This  thermometer  is  the  one  in  general 
use  among  scientific  men. 

Pure  dry  air  is  chiefly  a  mixture  of  oxygen,  nitrogen  and  carbon  di- 
oxide, containing  nearly  four  volumes  or  parts  of  nitrogen  to  one  part 
of  oxygen.  Figures  that  are  still  more  exact,  and  which  are  frequently 
used  iby  the  chemist  when  calculating  the  amount  of  oxygen  in  a  given 
volume  of  air,  are  as  follows: 

Per  cent. 

Carbon  dioxide    (CO.,)    0.23 

Oxygen    (O  )    - 20.93 

Nitrogen    (N^)    79.04 

Oxygen  is  slightly  soluble  in  waiter,  25  volumes  of  water  will  absorb 
one  volume  of  oxygen. 

The  average  pressure  of  the  atmosphere  at  sea  level  is  14.7  Ibs.  per 
square  inch.  This  is  called  the  pressure  of  1  atmosphere. 

The  weight  per  cubic  foot  of  any  gas  at  different  temperatures  and 
pressures  can  be  found  by  the  following  formula: 

Let  W  =  weight  in  pounds; 

V  =  volume  in  cubic  feet; 
B  =  barometric  pressure; 
S   =  specific  gravity; 
T  =  absolute  temperature. 

Hydrogen  has  no  taste  or  color.  The  pure  gas  has  no  odor,  though 
hydrogen  as  ordinarily  prepared  has  a  disagreeable  odor,  due  mainly 
to  impurities  in  the  metals  used.  Hydrogen  is  the  lightest  known  sub- 
stance. Volume  for  volume,  air  is  about  14.4  times  and  oxygen  16  times, 
and  water  11,000  times  heavier  than  hydrogen. 

By  specific  heat  is  meant  the  quantity  of  heat  necessary  to  raise 
the  temperature  of  a  substance  one  degree  compared  with  the  amount 
of  heat  necessary  to  raise  the  temperature  of  an  qual  weight  of  water 
one  degree. 

To  measure  the  specific  heat  of  a  body  the  following  will  suffice  as 
explanation:  The  quantity  of  heat  absorbed  by  the  cool  body  in  heating 
~  mass  X  change  in  temperature  X  specific  heat. 

The  quantity  of  heat  given  out  by  the  hot  body  in  cooling  =  mass 
X  change  in  temperature  X  specific  heat. 


THEORY  35 

Thus : 

M  =  mass; 

t  =  temperature  change; 
s  =.  specific  heat; 
Mts  —  MTs. 

It  will  be  noticed  that  the  heat  absorbed  by  the  cool  body  in  heat- 
ing is  exactly  the  amount  given  out  by  the  hot  body  in  cooling. 

In  internal  combustion  engines  the  pressure  in  the  cylinder  is  due 
to  the  action  of  the  heat  evolved  during  combustion.  The  capacity  for 
heat  of  the  combustible  mixtures  in  the  cylinder  is,  however,  small, 
whilst  the  temperature  of  combustion  is  high.  It  follows,  therefore,  that 
any  loss  of  heat  will  necessarily  seriously  affect  the  temperature  of  the 
products  of  combustion,  with  a  consequent  loss  in  efficiency. 

The  value  of  fuel  depends  upon  the  use  that  can  be  made  of  the 
store  of  latent  energy  which  it  contains. 

BOYLE'S   LAW 

Boyle's  Law  states  that  for  a  given  mass  of  gas,  at  constant  tempera- 
ture, the  pressure  varies  inversely  as  the  volume;  or,  using  the  letters 
P  and  V  to  represent  pressure  and  volume  respectively. 

1 

P  = ,  that  is,  the  product  P  X  V  =  constant. 

V 

FOR  AIR:  If  V  is  the  volume  of  1  Ib.  of  air  in  cu.  feet  and  P  is  the 
pressure  in  Ibs.  per  sq.  foot,  at  the  constant  temiperature  of  freezing 
water,  32°  F., 

Then  we  have:    U.  V.  :=  26220. 


CHARLES'  LAW 

Charles'  Law  states  that  when  a  given  mass  of  gas  expands  under 
constant  pressure,  equal  increments  of  temperature  produce  equal  in- 
crements of  volume,  and  it  also  states  that  all  gases  exipand  alike. 

Thus^if  VQ  is  the  volume  at  zero  temperature  of  a  given  quantity 
of  gas  expanding  at  constant  pressure,  and  if  V  is  its  volume  at  any 
other  temperature  TJ. 

Then  V  =  VQ  (1  +  aT* ),  where  a  is  a  constant. 

Thus  when  TI  is  in  Centigrade  units  a  is  very  nearly  1/273,  and 
when  T1  is  in  Fahrenheit  units  a  is  very  nearly  1/461. 

JOULE'S   LAW 

Joule's  Law  states  that  heat  and  mechanical  work  are  mutually  con- 
vertible, a  unit  of  heat  being  equivalent  to  a  certain  amount  of  mechani- 
cal work,  called  the  Mechanical  equivalent  of  heat. 


36  THEORY 

This  may  be  expressed  in  following:     w  =  J.  H. 

where  w  =  the  amount  mechanical  work  in  work  units, 
and  H  =  the  quantity  of  heat  in  heat  units, 

J  =  the  Mechanical  Equivalent  of  Heat  =  778  in  Fahren- 
heit units. 

The  fact  established  by  Joule  is: 

That  a  gas  expands  without  actually  doing  external  work  and  without 
taking  in  or  giving  out  heat  (i.e.,  without  changing  its  internal  energy), 
its  temperature  remains  constant. 

We  may  express  this  result  in  following: 

Heat  supplied  =  work  done  +  increase  in  internal  energy, 
or:     H  =  W  +  (E  —  E()). 


CHAPTER  III. 


MISCELLANEOUS   FORMULAS 

To  Find  Indicated  Thrust  of  a  Propeller: 

H.  P.  X  33000  X  per  cent  utilized 

Lbs.  Thrust  equals—  -  =  H>B.  thrust 

Fitch  X  revol.  X   100  of  propeller 

The  resistance  of  the  water  varies  as  the  square  of  the  speed.    The 
power  required  to  overcome  this  resistance  equals  the  cube  of  the  speed. 

To  Find  the  Power  of  the  Screw: 

P  equals  Power  required 
P  equals  Pitch  of  Screw 
L  equals  length  of  handle 
W  equals  weight  lifted 

weight  X  pitch 
P  —  -  r=  power  required. 

length  X  2  X  3.1416 

Displacement  of  Ship: 

Tons  X  35  X  12 

A  equals  —       -  =  Sectional  area  of  ship  at  water  level 

Inches  sunk 

Tons  X  35  X  12 

D  equals—  -  =  Displacement  in  inches. 

Area 

A  X  inches  to  sink 

T  e(}liais -  —  Tons  required  to  sink  ship  by 

35   x   12  amount  of  inches. 

Ton  cargo  X  35 

E  equals—  —  =  Co-efficient  of  displacement. 

1  X  b  X  d 

Number    of    feet 

—  =  decimal  part  of  1  nautical  mile. 

6080 


38  MISCELLANEOUS  FORMULAS 

Suppose,  for  example,  we  have  12  feet  to  consider  and  wish  -to  con- 
vert the  12  feet  in  decimal  terms  of  1  mile.  Thus: 

6080  ft. 

— —.00197  nautical  mile. 
12     ft. 

The  way  this  .Oi)197  would  be  used  in  the  kind  of  a  problem  this  is 
referred  to  is  as  follows: 

Suppose  we  have  a  propeller  that  has  a  pitch  of  15  feet,  and  the  loss 
in  slip  is  20  per  cent,  which  is  3  feet  per  revolution,  then  the  actual 
effective  pitch  is  12  feet,  or,  the  propeller  and  vessel  to  which  it  is  at- 
tached, will  advance  12  feet  per  revolution. 

Let  us  say  that  the  (propeller  turns  60  times  a  minute  and  it  is  de- 
sired to  find  how  ifar  the  ship  has  advanced  in  4  hours,  we  will  say: 

If  the  propeller  turns  60  times  per  minute,  then,  in  4  hours  it  will 
turn, 

60X60X4=14,400   revolutions. 

The  constant  we  will  use,  as  before  explained,  is  .00197,  and   so, 
14,400  X.00197=28.36+imiles   (say  28.4  miles). 

To  prove  the  constant  .00197  is  sufficiently  close  for  all  practical 
purposes,  let  us  work  out  the  same  problem  in  the  usual  way,  as  fol- 
lows : 

Effective  pitch  of  propeller— 12  feet. 
R.  P.  M.=  60. 
Hours  run=4. 

Then : 

12X60=720  feet  per  minute. 
720X60=43,200  feet  per  hour. 
43,200X4=172,800  feet  in  4  hours. 

As  there  are  6,080  feet  in  one  nautical  mile,  then  as  many  times  as 
C.080  is  contained  in  172,800  is  the  number  of  miles  (nautical)  that  the 
ship  has  advanced  in  the  4  hours: 

172,800-j-6,080=28.42  miles. 

The  reason  that,  by  the  use  of  the  constant,  we  get  a  slightly  dif- 
ferent answer,  viz:  28.36  +  ,  is  that  the  decimal  value  .00197  can  be 
worked  out  further,  hence  the  small  difference  as  noted. 


MISCELLANEOUS  FORMULAS  39 

THE    CIRCLE: 

The  circumference  of  a  circle  is  equal  to  the  diameter  multiplied 
by  3.1416. 

The  area  of  a  circle  is  equal  to  the  square  of  the  diameter  multi- 
plied by  .7854. 

To  find  the  length  of  an  Arc  of  a  Circle:  Multiply  the  diameter  of 
the  circle  by  the  number  of  degrees  in  the  arc  and  this  product  by 
.0087266. 

To  find  the  area  of  a  Sector  of  a  circle:  Multiply  the  numbsr  of 
degrees  in  the  arc  of  the  sector  by  the  square  of  the  radius  and  by 
.008727;  or,  multiply  the  arc  of  the  sector  by  half  its  radius. 


THE   TRIANGLE: 

Varieties. — Right  angled,  having  one  right  angle;  obtuse  angled,  hav- 
ing one  obtuse  angle;  isosceles,  having  two  equal  angles  and  two  equal 
sides;  equilateral,  having  three  equal  sides  and  equal  angles. 

The  sum  of  the  three  angles  of  any  triangle  equals  180  degrees. 

The  two  acute  angles  of  a  right  angled  triangle  are  complements 
of  each  other. 

Hypothenuse  of  a  right  angled  triangle,  the  side  opposite  the  right 


angle,  equals   V  sum  of  the  squares  of  the  other  two  sides. 

To  find  the  area  of  a  Triangle:  Multiply  the  base  by  half  the 
height. 

The  Area  of  a  Triangle  being  given  to  find  the  Length  of  the  Base: 
Base  equals  twice  the  area  divided  by  perpendicular  height. 

Area  of  a  Triangle  being  given  to  find  the  Height:  Height  equals 
twice  area  divided  by  base. 


QUADRILATERAL   FIGURE: 

To  find  the  Area:  Divide  the  figure  into  two  triangles;  the  sum  of 
the  areas  of  the  triangles  ds  the  area. 

THE    ELLIPSE: 

To  find  the  Area:  Multiply  the  two  diameters  together  and  the 
product  by  .7854. 

THE    SPHERE: 

To  Compute  the  Surface:  Multiply  the  diameter  by  the  circum- 
ference and  the  product  will  give  the  surface. 

To  Compute  the  Total  Volume:  Multiply  the  cube  of  the  diam- 
eter by  .5236. 


40  MISCELLANEOUS  FORMULAS 

THE  CYLINDER: 

To   Compute   the   Surface:      Multiply  the    length    by    the  circumfer- 
ence and  add  the  product  to  the  area  of  the  two  ends. 


EQUIVALENT    OF    MEASURE 
(VELOCITIES    AND    ACCELERATIONS) 

1  kine  —  1  centimeter  per  second  =  0.0328083  foot  per  second. 

1  radian  per  second  =  57.2958  degrees  per  second  =  0.159155  revolutions 

per  second. 

1  gravity  =  980.5966  centimeters  uer  sec.  =  32.1717  feet  per  sec. 
1  foot  pound  =  13557300  ergs  —  18325.5  gram-centimeters. 


EQUIVALENT    OF    MEASURE 
(MILES,    ETC.) 

1  Yard,  U.  S.  1.0000029  yard  British 

1  Yard,  British  0.9999971  yard  U.   S. 

1  Chain,    Gunter's    100    links 

1  Link 7.92    inches 

1  Cable  Length,  U.  S.  =  120  fathoms  =  960  spans  =  720  feet  =  219.457 

meters. 

1  League,  U.  S.  =  3  statute  miles  =  24  furlongs. 
1  International   Geographical    Mile    =  -    1/15°    at   Equator   =   7422    m    = 

4.611808  U  .S.  statute  miles. 
1  International  Nautical  Mile  =  1/60°  at  meridian  =  1852  m  =  0.999326 

U.  S.  nautical  miles. 
1  U.  S.  Nautical  Mile  =  1/60°  of  circumference  of  sphere  whose  surface 

equals  that  of  the  earth  =  6080.27  feet  =  1.15155   statute  miles  = 

1853.27  meters. 

1  British  Nautical  Mile  =  6080.00  feet  =  1.15152  statute  miles  =  1853.19 
meters. 


TO     FIND     THE     HORSE     POWER     REQUIRED    TO     DRIVE     A     SHIP 
THROUGH     THE    WATER     AT    A    GIVEN     SPEED 

Area  of  immersed  midship  section  X  knots  per  hr. 
H.   P.   equals 

600 

Horse  Power  required. 

Note:     The  resistance  varies  as  the  square  of  the  speed, 


MISCELLANEOUS  FORMULAS  41 


Valve    Formula: 


Half  the  travel  of  the  valve-lap  equals  the  greatest  opening. 
Greatest  opening  X  length  of  port  equals  Area  of  opening. 
Lap  plus  lead  plus  exhaust  lap  equals  exhaust  opening 

Twice  the  lap  plus  lead  2  x  stroke  equals  Point  of 
cut-off  from  end  of  stroke. 

Travel 

Convenient    Formulas: 

GXP 

S  equals  -  —  =  length  of  stroke. 

P 

S  X  P 

C  equals  -  —  =  point  of  cut-off. 

P 

S  X  P 

P  equals  -  —  =  absolute  pressure. 

C 

P  X  C 

p  equals  -  —  =  terminal  pressure. 

S 

R  equals  S  -f -  C  =  ratio  of  expansion. 

Pressure  on  Guide: 

Area  of  piston  X  P  X  length  of  crank 

P  equals  —  =  pressure  per  sq. 

Area  of  guide  X  length  of  connecting  rod  in.  on  guide. 

Crank    Pin: 

Area  of  piston  X  pressure 

P  equals —  —  pressure  per  sq.  inches  on  pin. 

Diam.  X  length  crank  pin 

Pressure: 

P  equals  Pressure  above  atmospheric  pressure  when  denoting  burst- 
ing or  safe  working  pressure,  gauge,  or  safety  valve  pressures  of  tank. 

P  equals  Absolute  pressure  when  denoting  engine  pressures, 
strains  on  shafting,  etc. 


42  MISCELLANEOUS  FORMULAS 

1.  Example:  A  propeller  is  9'  in  diameter,  20"  across  the  blades, 
and  the  forward  corner  is  OVa"  in  advance  of  the  after  one.  What 
is  the  pitch? 

p  —  piece  of  pitch; 

G  =  piece  of  circumference; 

p  =  whole  pitch; 

C  =  whole  'Circumference; 

20    inches    piece    of    thread; 

9  5/10  piece  of  pitch. 

400  minus   90.25   equals   309.75 

9  X  12  equals  108"  diameter  of  wheel,  (12"  =  1  foot) 
3.1416  X  108"  equals  339.2928  inches  whole  circumference, 
339.2928  inches  X  9.5  equals  3223.2816  inches. 
3223.2816  inches  divided  by  12   equals  268.6068  ft. 
268.6068  divided  by  17.6  equals  15.26  plus  ft.-^pitch. 

C  X  p 
P  equals  -  or 


as  c  =  to  C  as  p  =  to  P 

20"  X  20  =  400"  400.00 

9.5"  X  9.5  =  90.25  90.25 


309.75  =  17.6"  part  of  circumference.  309.75 

Answer:     15.26  plus  ft.  pitch. 


2.  Example:  The  pitch  of  a  propeller  is  18  ft.  and  makes  70 
r.  p.  m.  what  is  'the  speed  of  the  ship  in  knots  per  hour  allowing 
20  per  cent  off  for  slip? 

C  =  constant  6068  ft. 

P  =  pitch  of  wheel; 

R  =  revolutions  per  minute 

S  =  percentage  of  slip; 

K  —  knots;   (60  minutes  in  1  hour) 

6068  ft.  equals  1  knot. 

P  X  R  X  60  X  S 
K  equals 


MISCELLANEOUS  FORMULAS  43 

Efficiency: 

A  crude  definition  of  efficiency  is: 
What  you  get 


What  you  paid  for  it 

The    Mechanical    Efficiency   of  the    Engine   is: 

B.  H.  P. 


I.  H.  P. 

Apparent  Slip: 

The    definition    of   this   term    means   following: 

A  ship  which  is  driven  at  an  abnormal  speed  of  V  knots  per 
hour  by  a  propeller  having  a  pitch  of  p  feet,  and  making  r  revolutions 
per  minute,  the  apparent  slip  is  the  quantity  computed  by  the  equa- 
tion 

pr  —  101.3V 


pi- 


Real    and   Apparent   Slip: 

The  slip  of  propeller  may  be  defined  in  following: 

pr  —  101.3  Va 

s  = 


pr 

Where  V  a  is  the  speed  of  the  ship  in  knots  per  hour,  p  is  the 
pitch  in  feet  and  r  is  the  number  of  revolutions  per  minute. 

Pitch   Ratio  and  Slip: 

The  importance  of  determining  the  pitch  ratio,  where  a  change  of 
propellers  necessitates  the  accuracy  of  the  type  desired  may  be  ex- 
plained in  following: 

For  large  ships  the  pitch  ratio  usually  range  from  1.0  to  1.5  and 
the  apparent  slip  from  0.10  to  0.20;  both  pitch-ratio  and  slip  increas- 
ing with  the  speed-length-ratio.  The  efficiency  of  the  full-faced  type 
ranges  from  0.45  to  0.75,  increasing  with  the  pitch  ratio,  and  being 
larger  for  narrow  blades  and  for  propellers  with  few  blades  (three  or 
two).  The  variation  in  this  case  for  a  given  type  of  propeller  is  not 
large  and  can  be  known  approximately  in  advance.  For  a  given 
range  of  slip  the  efficiency  changes  but  little,  but  there  is  an  appre- 
ciable falling  off  for  large  slips.  These  conditions  vary  somewhat  for 
the  various  pitch-ratios. 


44  MISCELLANEOUS  FORMULAS 

Number  of   Propellers: 

The  efficiency  establishment  in  difference  of  single  or  twin  pro- 
pulsion, depends  a  great  deal  on  prevailing  conditions.  The  differ- 
ences are  not  large  and  any  of  aforementioned  type  may  be  of  equal 
efficiency.  A  single  engine  is,  of  course,  simpler  and  cheaper  than 
two  engines,  taking  in  consideration  the  initial  expenses.  For  moderate 
powers  and  speeds  a  single  screw  will  be  chosen  unless  there  are 
distinct  advantages  otherwise,  such  as  the  elimination  of  a  heavy  weight 
main  engine  to  be  substituted  with  twin  engines,  which  are  as  easily  op- 
erated as  the  single  engine,  owing  to  the  facility  afforded  in  managing 
Diesel  power. 

Thrust    Computation: 

To  compute  the  thrust  per  square  inch  we  may  first  find  the 
effective  horsepower  by  multiplying  the  indicated  horsepower  by  the 
coefficient  of  propulsion — from  0.5  to  0.65.  The  effective  horse-power 
may  be  multiplied  by  33,000  to  find  the  foot-pounds  per  minute,  and  this 
quantity  divided  by  the  speed  of  the  ship  in  feet  per  minute  (101.3V) 
will  give  the  tow-rope  resistance;  this  last  quantity  must  be  divided 
by  1  -  +  to  find  the  thrust  of  the  propeller;  so  that 

33000  E.  H.  P. 
Thrust  — 


101.3  V  (1  —  t) 

in  which  V  is  the  speed  of  the  ship  in  knots  and  t  is  the  thrust  deduction 
(about  0.1). 

Shaft    Diameters: 

FOUR  CYCLE  DIESEL  ENGINE  AT  120  R.P.M.: 

6  Cylinders,  26"  diameter  X  42"  stroke,  500  Ibs.,  initial  pressure. 


3 

cyl.  cliam.'~'  x  press.  X  stroke  = 
Diameter  Shaft  =  constant  — 

f  (shaft  stress) 


262  x  500  X  42 

.97  V—  —=11.85' 

7500 


MISCELLANEOUS  FORMULAS  45 

FOUR  CYCLE  DIESEL  ENGINE  AT  90  R.P.M.: 
6  Cylinders,  30"  X  48",  500  Ibs.  initial  pressure. 


3  /     302  X  500  48 
Diameter  Shaft  =  .97  \  . — 

7500 


TWO  CYCLE  DIESEL  ENGINE  AT  115  R.P.M.: 
6  Cylinder,  22"  x  32",  500  Ibs.  pressure. 


3  /    222  X  500  X  32 

Diameter  Shaft  =  1.04  \  —  ==  10.48' 

7500 


TWO  CYCLE  DIESEL  ENGINE  AT  90  R.P.M.: 

6  Cylinders,  24"  X  38",  500  Ibs.  initial  pressure. 


242  x  500  X  38 

Diameter  Shaft  =  1.04  \l  -  =  11.75' 

7500 


2  —  4  Cycle  Diesel  Engines  running  in  parallel  at  150  R.  P.  M. 
with  single  Reduction  Gear  <to  one  Main  Shaft  running  at  85  R.  P.  M. 
Ratio  of  gearing  1.75  .to  1,  single  impulses. 

8  Cylinders,  17"  X  27",  500  Ibs.  initial  pressure. 

The  two  engines  form  pratically  one  16  Cylinder  Engine.  The 
twisting  movement  given  under  the  root  sign  under  7  is  to  be  multi- 
plied by  the  gear  ratio  so  that 


3|-    D-'  x  P  X  S  X  1.75 

Diameter  Shaft  =  constant     \    Constant  for  16 

7500  Cylinders. 

Four  Cycle  is  1.1. 


172  X  500  X  27  X  175 

Diameter  Shaft  =\|  -—=10.6" 

7500 


46  MISCELLANEOUS  FORMULAS 

Engines  with  smaller  cylinders  running  at  higher  revolutions 
and  having  consequently  a  greater  gear  ratio  will  'have  line  shafts  in 
diameter  than  the  above-  engine. 

(Note:  Aforementioned  formulas  are  from  "Compilations  by 
Joseph  Heckimg,  Technical  Staff,  American  Bureau  of  Shipping). 

Strength   of  Seams: 

P  equals  pitch; 

D  equals  diameter  of  rivets; 

T   equals  thickness  of  plates  in  inches; 

A  equals  area  of  rivets; 

N   equals   No.  of  rows. 

(a)         P  —  D     >|  ( 

--  \    x   100  equals!    Percen^  of  strength  of  rivets  as 

"        compared  with  the  solid  plate. 

Percentage  of  strength  of  rivets  as 


p 

« 


v  m 

X  i 


X   100 

1       compared  with  the  solid  plate. 


Engine    Formula:    (Slow-speed  heavy  duty   types) 

The  'stroke  equals  the  mean  diameter  of  cylinders. 
D  divided  by  10  equals  diameter  of  piston  rod; 
D  divided  by  14  equals  diameter  of  piston  rod  at  bottom  of  thread. 
D  divided  by  20  equals  diameter  of  connecting  rod  bolts  (2). 

D  X  stroke 
-  zz:   diameter  of  crankshaft  journals. 


D  x  S 

=  diameter  of  tunnel  shaft  journal. 


10 

p   =   pressure   in  cylinder 

L   =    length   of    stroke 

A  =  area  of  cylinder 

N   =   number  of   revolutions   per   minute 

•C  =  num'ber  of  cylinders 

For  single  acting  two-cycle  type,  which  has  one  impulse  for  each 
revolution,  use  the  following  formula: 

PLAN 
I.  H.  P.  =  - 

33000 


MISCELLANEOUS  FORMULAS  47 

For   four-cycle,    which   has    an    impulse    on    alternate    strokes,    use 
the  following  formula: 

PLAN 

I.  H.  P.  = 


2  x  33000 

Note:  Above  formulas  give  horse-power  of  one  cylinder.  To 
ascertain  the  horse-power  on  multi-cylinder  engines,  multiply  by  number 
of  cylinders. 

Formulas  for   Brake    Horse-power: 

CLAN 
For  two-stroke  cycle  engine  B.  H.  P.  = 


750 
CLAN 


For  four-stroke  cycle  engine  B.  H.  P.  = 


1000 

Or  by  following:      (Four-cycle  engine  single  acting) 

P  X  s  X  n 


N  = 


880 

In  the  case  of  the  two-cycle  engine,  single  acting: 

P  X  s  X  n 


N  = 


500 
Where 

N  =  B.  H.  P. 

n  =  revolutions  per  minute 
P  =  piston  area  in  sq.  in. 
s  =  piston  <atroke  in  feet. 

Estimated  Indicated  Horse  Power  Formula: 

Values  for  the  accuracy  of  the  engine  performance  can  be  given 
only  when  indicator  cards  are  taken.  Indicated  Horse  Power  is  equal 
toPXLXAXN-r-  33,000, 

where — 


P  =  mean  effective  pressure  in  pounds  per  square  inch  on 

the  piston; 

L  =  length  of  piston  stroke  in  feet; 
A  =  area  of  piston  in  square  inches; 
N  =  number  of  working  strokes  /per  minute; 
33,000  =  number  of  foot  pounds  of  energy  expended  per 

minute  to  make  one  horse  power. 


48  MISCELLANEOUS  FORMULAS 

Mean  effective  pressure  should  be  measured  on  indicator  cards  by 
an  average  planimeter.  Mean  effective  pressure  between  exhaust  and 
suction  strokes  in  a  four-cycle  engine  means  a  thermo-dynamic  loss 
of  energy  from  the  piston.  It  should  be  deducted  from  the  mean 
effective  pressure  between  compression  and  working  strokes  before 
computing  net  power. 

Ratio  of  Air  Supplied  to  Air  Used    Formula: 
Following  formula  may  be  applied: 

N 
R  (ratio)  = 


N— (3.8X0) 
wherein 

N  =  per  cent  of  nitrogen  in  the  exhaust  gases: 
O  =  per  cent  of  oxygen  in  the*  exhausit  gases 
3.8    =   the    approximate    ratio    of    nitrogen    to    oxygen    in 
fresh   air. 

All   these   quantities   refer  to   volumes  of  gases   with  all   saturated 
properties  eliminated.     The    per    cent    of    nitrogen    is    assumed    equal 
to  the  difference  between  100%  and  the  total  carbon  dioxide  and  exygen. 
oxygen. 

Thermal  efficiency  of   Engine,   Fuel   to   Piston   Formula: 

E  (efficiency)  =  B.  t.  u.  equivalent  of  net  indicated  power  per 
hour  -r-  B.  t.  u.  supplied  in  fuel  per  hour.  (The  B.  t.  u.  equivalent  of 
one-horse-power-hour  is  taken  as  2545,  which  corresponds  to  778  foot- 
pounds as  the  equivalent  of  one  British  thermal  unit.) 

B.  t.  u.  in  Brake  Horse  Power  per  Hour  Formula: 

The  B.  t.  u.  in  brake  horse  power  per  hour  =  brake  horse  power 
X  2545. 

B.  t.  u.  in  Jacket  Cooling  Water  per  Hour  Formula: 

The  B.  t.  u.  in  jacket  cooling  water  per  hour  =  pounds  of  water 
flowing  per  hour  X  temperature  rise  in  degrees  Fahrenheit. 

B.  t.  u.  in  Cylinder  Water  per  Hour  Formula: 

The  B.  t.  u.  in  cylinder  waiter  per  hour  =  pounds  of  water  fed 
per  hour  y^  B.  t.  u.  absorbed  by  one  pound  of  water.  B.  t.  u.  per  pound 
of  water  is  made  up  of  three  parts,  assumed  as  follows: 

One  B.  t.  u.  is  absorbed  for  each  degree  (F.)  rise  up  to  212° 
Fahrenheit.  As  the  water  is  turned  into  heated  condition  from  cold, 
970  B.  t.  u.  are  absorbed.  For  each  degree  of  heat  above  212°  F. 
then  added,  up  to  temperature  of  exhaust  gases,  0.48  B.  t.  u.  is  absorbed. 


MISCELLANEOUS  FORMULAS  49 

This  method  is  not  scientifically  accurate  because  of  pressures 
other  than  atmospheric  imposed  uipon  heat  in  the  exhaust  and  its 
consequential  vapor,  however  the  difference  is  negligible  in  general  cal- 
culation. 

To  Find  the  Pitch  of  Propeller  in  Practical  Way: 

A  simple  way  to  find  the  pitch  of  a  propeller  is  as  follows: 
At  some  place  on  the  blades  of  every  propeller  (there  will  be  a  place 
that  is  at  an  angle  of  45  degrees  to  the  center  line  of  the  shaft. 
Secure  a  45  degree  (draftsman's)  triangle  and  find  the  place  on  one  of 
the  blades  where  it  can  be  applied.  Next  measure  the  diameter  of  the 
propeller  at  the  place  where  you  'have  applied  the  45  degree  triangle, 
and,  finally,  multiply  that  diameter,  measured  in  feet,  by  3.1416  and 
that  gives,  directly,  the  pitch  in  feet.  For  all  practical  purposes, 
this  is  the  average  pitch  of  the  propeller. 

Suppose,  for  example,  that  you  ihave  a  propeller  that  measures 
over  the  tips  of  the  blades,  8  feet;  also,  that  .the  place  where  the 
angle  of  the  blade  is  at  45  degrees  with  'the  center  line  of  the  shaft  is, 
we  will  say,  at  4  feet  diameter,  or  2  feet  from  the  center  of  the  bore 
of  the  propeller,  which  is  the  same  thing.  Then,  following  the  rule 
given  above,  we  have: 

3.1416    X   4  =  12.5664  feet,  pitch,  average  of  that  propeller. 

How  to  Find  the  Decimal  Part  of  a  Mile  that  a  Propeller  Will  Advance 
in  One  Revolution,  or  the  Constant  of  a  Propeller,  that  When  Multi- 
plied by  the  Number  of  Revolutions  in  a  Given  Time,  Will  Give  the 
Distance  the  Propeller  Has  Advanced  (hence  also  the  ship)  in  the 
Same  Time: 

A  nautical  mile  is  said  to  be  6080  feet;  or  it  may,  for  expla- 
natory purposes,  be  stated  thus: 

1  mile  (nautical)  =  6080  feet. 

Any  number  of  feet  less  than  6,080  will  first  be  stated  like  this, 
when  it  is  desired  to  convert  into  decimals  of  a  mile: 

Example: 

Find    the    velocity    of    water    in  feet  per  second,  in  two  discharge 
pipes,    one    ±%"    and    the   other    3";    also    the    difference    in    velocity. 
Diameter   of    water    end   of  jpump   is    4    inches,    stroke    12    inches,    60 
strokes  per  minute  and  piston  rod  1%"  in  diameter. 
Solution: 

4  X  .7854  —  12.5664  sq.  in.,  area  of  cylinder  head; 

\y2  X  .7854  =  1.7671  sq.  in.,  area  of  piston  rod; 

12.5664  —  1.7671  —  2  =  11.6829  sq.  in.  to  good,  per  stroke; 

11.6829    X   12   X  60  =  8411.688  cu.  in.  water  delivered  per  min. 

4%    X   .7854  =  15.9043  sq.  in.,  area  of  4^  in.  pipe; 

8411.688  —  15.9043  X  60  X  12  =  .734  ft.  per  second; 


50  MISCELLANEOUS  FORMULAS 

3  X  .7854  =  7.0686  sq.  in.,  area  of  3"  pipe; 

8411.688  —  7.0686  X  60  X  12  =  1.652  fit.  per  sec.  in  3"  pipe; 

1.652  —  .734  =  .918  ft.  per  second,  difference  in  velocity. 

Revolution  Calculation: 

At  10:00  A.  M.  the  counter  reads  956780,  at  10:50  you  set  the 
clock  back  10  minutes,  what  will  the  counter  read  at  11:00  A.  M. 
if  .the  engines  are  making  332  R.  P.  M.? 

Solution: — From  10:00  A.  M.  to  11:00  A.  M.  is  60  minutes,  to 
which  imust  >be  added  the  10  minutes  the  clock  was  set  back  as  the 
engine  has  actually  to  run  70  minutes  before  11:00  A.  M.  If  the  engine, 
or  engines,  are  making  332  R.  P.  M.  for  70  minutes  it  will  be  332  X  70  = 
23240  R.  P.  M. 

Then:       956780  H-  23240  —  980020  reading  at  11:00  A.  M. 


STANDARD   TESTS    APPLIED    TO    INTERNAL    COMBUSTION 
MACHINERY 

Brake  Horse  Power: 

The  determination  of  brake  horse  power  is  the  same  for  internal 
combustion  engines  as  for  steam  driven  engines. 

Measurement  of   Heat-Units   Consumed   by    Engine: 

The  number  of  heat  units  used  is  found  by  multiplying  the  number 
of  pounds  of  oil  or  the  cubic  feet  of  gas  consumed  by  the  total  heat  of 
combustion  of  the  fuel  as  determined  by  the  calorimeter  test. 

In  establishing  the  total  heat  of  combustion  no  deduction  is  made 
for  the  latent  heat  of  the  water  vapor  in  the  products  of  combustion. 

Measurement  of  Jacket-Water  to  Cylinder  or  Cylinders: 

In  measuring  the  jacket-water  the  method  of  passing  it  through  a 
water  meter,  or  to  have  it  flowing  from  a  measuring  tank  on  its  dis- 
charge, is  reliable. 

Indicated   Horse-Power: 

Accurate  tests  made  to  establish  the  Indicated  Horse-Power  must  be 
in  a  manner  that  no  possible  reaction  can  occur  to  engine,  by  unneces- 
sary bends  in  exhaust  piping.  All  connection  necessary  should  be,  if 
possible,  to  the  cylinder  head.  The  use  of  Steam  Indicators  in  connec- 
tion with  test  should  be  avoided  and  special  types  employed  manufac- 
tured for  Internal  Combustion  Engines. 

Standards  for  Economy  and   Efficiencies: 

Comparison  tests  between  steam  and  Internal  Combustion  Engines 
require  actual  generating  processes  employed  for  either  prime  mover. 
It  is  imperative  to  confine  the  actual  losses  incurred  by  either  engine 
through  its  respective  method  of  heat  energy  produced. 


MISCELLANEOUS  FORMULAS  51 

Thermal    Efficiency: 

In  determining  bhe  thermal  efficiency  ratio  per  Indicated  Horse- 
Power  or  per  brake  horse-power  for  internal  combustion  engines,  the 
following  formula  may  be  used,  expressed  by  fractions: 

2545 


B.  T.  U.  per  H.  P.  per  hour 

Dimensions: 

It  is  recommended  that  following  procedure  be  taken,  in  establish- 
ing accurate  tests  of  engine:  Take  the  dimensions  of  the  cylinder  or 
cylinders  whether  already  known  or  not.  The  proper  time  to  ascertain 
this  is  while  the  cylinder  or  cylinders  are  hot  and  in  working  order. 
In  case  where  wear  is  shown,  determine  the  average.  Also  measure  the 
compression  space  or  clearance  volume,  which  should  be  done,  if  prac- 
ticable, by  filling  the  spaces  with  water  previously  measured,  the  proper 
correction  being  made  for  the  temperature. 

Fuel: 

The  fuel  used  for  the  test  should  be  specified  and  the  correct  high- 
est calorific  value  for  fuel  used  known,  to  determine  the  maximum 
efficiency  of  engine. 


METRIC   CONVERSION    TABLE 
(SOLIDS  AND   LIQUIDS) 

Millimetre  X  .03937  =  Inches. 
Millimetres   X  25.4  =  Inches. 
Centimetres  X  .3937  =  Inches. 
Centimetres  -r-  2.54  —  Inches. 
Metres  X  39.37  =  Inches. 
Metres  X  3.281  =  Feet. 
Metres   X   1.094  =  Yards. 
Kilometres  X  .621  =  Miles. 
Kilometres  -r-  1.6093  =  Miles. 
Kilometres  X  3280.7  —  Feet. 
Square  Millimetres  X  .0155  —  Sq.  Inches. 
Square  Millimetres  -f-  645.1  =  Sq.  Inches. 
Square  Centimetres  X  .155  =  Sq.  Inches. 
Square  Centimetres  -=-  6.451  =  Sq.  Inches. 
Square  Metres  X  10.764  =  Sq.  Feet. 
Square  Kilometres  X  247.1  =  Acres. 
Cubic  Centimetres  -f-  16.383  =  Cu.  Inches. 
Cubic  Centimeters  -r-  3.69  =  Fluid  Drachms. 


52  MISCELLANEOUS  FORMULAS 

Cubic  Centimetres  -4-  29.57  =  Fluid  Ounces. 

Hectare  X  2.471  =  Acres. 

Cubic  Metres  X  35.315  =  Cubic  Feet. 

Cubic  Metres  X  1.308  =  Cubic  Yards. 

Cubic  Metres  X  264.2  Gallons  (231  Cu.  Ins.) 

Litres  X  61.022  =  Cubic  Inches. 

Litres  X  33.84  =  Fluid  Ounces. 

Litres  X  .2642  =  Gallons  (231  Cu.  Ins.) 

Litres  -=-  3.78  ==  Gallons  (231  Cu.  Ins.) 

Litres  -=-  28.316  =  Cubic  Feet. 

Hectolitres  X  3.531  =  Cubic  Feet. 

Hectolitres   X   2.  84  =  Bushels   (2150.42  Cu.  Ins.) 

Hectolitres   X  .131  =  Cubic. Yards. 

Hectolitres  -f-  26.42  =  Gallons  (231  Cu.  Ins.) 

Grammes   X   15.432  =  Grains. 

Grammes  -4-  981  =  Dynes. 

Grammes  (Water)   -*-  29.57  =  Fluid  Ounces. 

Grammes  -=-  28.35  =  Ounces  Avoirdupois. 

Grammes  Per  Cu.  Cent,  -i-  27.7  —  Lbs.  Per  Cu.  Ins. 

Joule  X   .7373  =  Foot  Pounds. 

Kilogrammes  X  2.2046  =  Pounds. 

Kilogrammes  X  35.3  =  Ounces  Avoirdupois. 

Kilogrammes  -i-  1102.3  =  Tons  (2000  Lbs.) 

Kilogrammes  Per  Sq.  Cent.  X  14.223  =  Lbs.  Per  Sq.  Inch. 

Kilogrammes  Metres   X   7.233  =  Foot  Pounds. 

Kilo  Per  Metre  X  .672  —  Lbs.  Per  Foot. 

Kilo  Per  Cu.  Metre  X  .026  —  Lbs.  Per  Cu.  Foot. 

Kilo  Per  Cheval  X  2.235  =  Lbs.  Per  H.  P. 

Kilo-Watts  X  1.34  =  Horse  Power. 

Watts  -i-  746.  =  Horse  (Power. 

Watts  -f-  .7373  =  Foot  Lbs.  Per  Second. 

Calorie  X  3.968  =  B.  T.  U. 

Cheval  Vapeur  X  3.968  =  Horse  Power. 

(Centigrade   X   1.8)   +  32  =  Degrees  Fahrenheit. 

Gravity  Paris  =  980.94  Centimetres  Per  Sec. 


POWER    EQUIVALENTS. 
One  Horse  Power  Is  Equal  to: 

1,980,000 foot  pounds  per  hour 

33,000  foot  pounds  per  minute 

550  .__foot  pounds  per  second 


MISCELLANEOUS  FORMULAS 

273,740  kilogram  metres  per  hour 

4.562.3  kilogram  metres  per  minute 

76.04  kilogram  metres  per  second 

2,552  British  Thermal  Unit  per  hour 

42.53  British  Thermal  Unit  per  minute 

0.709  British  Thermal  Unit  per  second 

0.746  Kilowatt 

746  Watts 

One   Kilowatt  Is   Equal  to: 

2,654,400  foot  pounds  per  hour 

44,239  foot  pounds  per  minute 

737.3  foot  pounds  per  second 

366,970  kilogram  metres  per  hour 

6,116.2  kilogram  metres  per  minute 

101.94  kilogram  metres  per  second 

3.438.4  British  Thermal  Unit  per  hour 

57.30  British  Thermal  Unit  per  minute 

0.955  British  Thermal  Unit  per  minute 

1,000  Watts 

1.34  horse  power 

One  Watt   Is  Equal  to: 

2,654.4  foot  pounds  per  hour 

44.239  foot  pounds  per  minute 

0.737  foot  pounds  per  second 

366.97  kilogram  meters  per  hour 

6.12  kilogram  metres  per  minute 

0.102  kilogram  metres  per  second 

3.4384  British  Thermal  Unit  per  hour 

0.0573  British  Thermal  Unit  per  minute 

0.000955  ____British  Thermal  Unit  per  second 

0.001  Kilowatt 

0.001.340.6  Horse  power 

One  Foot  Pound  Is  Equal  to: 

0.0000003767       Kilowatt  per  hour 

0.0000226  Kilowatt  per  minute 

0.001356  Kilowatt  per  second 

0.000000506  Horse  Power  per  hour 

0.0000303  Horse  Power  per  minute 

0.001818  Horse  Power  per  second 

0.0003767  Watt  per  hour 

0.0226  Watt  per  minute 

1.356  Watt  per  second 

One   Foot  Pound  Is  Equal  to: 

1.3325  Kilogram  metres 

0.001288  .-British  Thermal  Unif. 


53 


CHAPTER  IV. 


PRINCIPLES    OF    DIESEL    OPERATION 


It  must  be  admitted  that  great  progress  has  been  made  of  late 
to  standardize  Diesel  machinery  on  same  basis  as  found  to  day  among 
steam  driven  engines.  In  fact,  a  similar  plan  will  be  adopted  as  time 
advances.  It  is  true,  that  mechanical  contrivances  covered  by  numer- 
ous patents  are  held  in  many  instances  the  most  vital  part  in  operation. 
It  is  also  true,  that  the  same  condition  existed  a  number  of  years 
ago  when  steam  machinery  was  in  its  pioneer  days. 

By  careful  observation  in  pratical  performance  engineers  were 
enabled  to  find  methods  of  better  results  in  steam  engineering.  Even 
the  most  insignificant  defects  were  found  to  be  worthy  of  consider- 
ation. The  result  was  the  standardization  of  reciprocating  steam 
machinery.  So  it  is  to-day  a  fact,  that  in  this  respect  a  standard 
in  construction  was  made  possible  and  very  little  difference  exists 
in  this  type  of  machine. 

The  same  was  accomplished  with  the  Internal  Explosion  Engine, 
or  such  machinery  'receiving  their  power  stroke  by  impulse  of  explo- 
sion such  as  the  gasoline  driven  engine.  As  will  be  observed,  the 
prevailing  principle  is  identical  in  every  respect.  In  either  the 
two-stroke  cycle  or  engines  following  the  principle  of  four-stroke 
cycle  the  relative  identity  in  construction  has  been  accomplished. 
While  manufacturers  in  some  instant  adhering  to  the  overhead-valve, 
T-head  cylinder  or  L-head  type,  etc.,  nevertheless  there  is  a  prevail- 
ing standard  governing  the  system  as  a  whole.  It  will  be  acknowledged, 
that  in  this  type  of  engine  construction  a  great  deal  of  improvement 
will  be  accomplished,  but  the  laws  established  will  remain. 

This,  of  course,  would  be  impossible  in  the  case  of  Diesels. 
Problems  of  reversing  of  Diesel  engines  and  fuel  injection  processes 
might  easily  find  solution.  Valve  arrangements  necessary  to  reverse 
the  power  plant  depends  a  great  deal  on  future  development.  The  usual 
procedure  in  accomplishing  this  is  by  cam  operation.  In  most  cases 
there  are  levers  by  which  cams  are  operated  causing  the  opening  of 
its  respective  ports. 

In  most  engines  of  marine  and  stationary  types,  horizontal 
cam-action  is  extensively  employed.  In  this  case,  where  two  sets  of 
cams  performing  the  purpose  of  the  alteration,  cams  are  generally 
directly  in  conjunction  with  shaft.  Opening  of  valves  is  thereby 
accomplished  in  the  movement  of  the  shaft  in  longitudinal  direction. 
In  some  cases  independent  cam  arrangements  are  favored  by  builders. 


PRINCIPLES  OF  DIESEL  OPERATION 


55 


The  methods  of  fuel  injection  is  a  subject  which  can  be  solved 
and  ultimately  will  have  to  be  considered.  Arguments  in  favor 
of  Solid  Injection  as  opposed  to  Air  Injection  is  merely  a  matter 
of  opinion.  Both  systems  have  proven  satisfactory  and  the  fuel  con- 
sumption may  be  considered  nearly  on  an  equal.  The  principal  reason 
advanced  against  the  use  of  Air  Injection,  may  be  expressed  through  the 
necessity  of  compressor  equipment  in  the  case  of  the  latter  system 

Compressor  installation  is  imperative.  Even  with  the  employ- 
ment of  solid  injection  provision  must  <be  made  to  supply  air  for 
starting  purposes.  There  are  commendable  features  in  the  use  of  solid 
injection,  but  not  important  enough  to  make  this  method  exclusive  in 
adoption. 


Cross-sectional  view  of  Nordberg  Diesel  Engine. 

In  this  type,  similar  to  the  Busch-Sulzer  Engine, 

a  true  representation  of  two-cycle  principle  of 

construction  is  to  be  found. 


56 


PRINCIPLES  OP   DIESEL  OPERATION 


PRINCIPLES  OF  DIESEL  OPERATION  57 

In  the  comparison  between  the  two-cycle  and  four  cycle  type 
the  primary  difference  will  be  found  in  the  arrangement  of  valves  and 
the  requirement  of  the  scavenging  pump  on  the  two-cycle  engine. 

Added  mechanism,  such  as  valves,  etc.,  necessitates  added  ex- 
penses on  the  four-cycle  than  on  two-cycle  construction.  These  again 
are  matters  which  after  carefully  going  in  detail  are  not  seriously 
acting  against  this  type  of  construction. 

The  introduction  of  two-cycle  double  acting  engines  appears 
not  to  meet  with  favor  in  .the  United  States.  There  is  no  question  as 
to  the  advantages  of  this  class  of  machine.  It  may  well  be  stated 
that  the  two-cycle  double  acting  engine  is  a  machine  of  high  merits 
owing  to  its  enormous  developing  of  power.  In  economy  it  has  no  equal. 
It  differs  inasmuch  as  each  stroke  is  a  working  stroke.  The  distribu- 
tion of  power  in  its  general  arrangement  of  cylinders  gives  an  exer- 
tion of  double  action  through  construction  of  seperate  cylinders  re- 
ceiving its  imipulse  through  seperate  inlet  valves  above  and  below. 

The  reason  for  lack  of  interest  in  this  type  of  construction  in 
the  United  States,  may  be  found  in  the  fact  that  a  tendency  exists 
in  the  adoption  of  large  types  of  engines  with  the  simplest  mech- 
anism. This  theory  is  indisiputably  the  best.  An  engine  built  to 
perform  work  should  be  constructed  of  good  material  and  all  neces- 
sary complicated  mechanism  eliminated. 

The  cycle  of  operation  governing  Diesels  is  exceedingly  simple, 
being  based  on  two  natural  laws — '• 

First — Air  compressed  in  a  closed  cylinder  will  develop  heat 
in  proportion  to  the  degree  and  character  of  compression. 

Second — Any  product  of  petroleum  designated  in  trade  as  crude 
or  fuels  oils,  if  properly  atomized,  will  ignite  spontaneously  when  in- 
jected in  a  cylinder  of  compressed  air,  whose  temperature  has  been 
raised  above  the  fire  test  of  the  fuel. 

The  Diesel  engine  differs  from  a  gas  engine  from  the  fact  that 
it  is  a  constant  pressure  engine.  That  is,  the  injection  of  fuel  into 
the  cylinder  is  timed  and  controlled  to  maintain  constant  pressure 
during  its  introduction,  while  in  a  gas  engine  a  constant  volume  of 
mixture  is  taken  into  the  cylinder  and  after  compressing  same  to  a 
safe  limit  (about  70  Ibs.)  the  mixture  is  ignited  by  some  auxiliary 
mechanism  and  the  pressure  instantly  rises  in  the  nature  of  an  explo- 
sion to  a  degree  depending  on  the  volume  of  the  mixture. 

Now  while  the  terminal  pressures  are  about  the  same  in  both 
types  of  engines,  the  efficiency  of  the  Diesel  is  twice  that  of  the 
gas  engine  due  to  compressing  a  non-explosion  fluid  to  a  high  tem- 
perature before  injecting  the  fuel,  then  controlling  this  injection 
so  that  combustion  continues  for  a  pre-determined  time,  varying  with 
the  load,  before  expansion  begins. 

This  process  enables  the  Diesel  to  maintain  a  much  higher  mean 
effective  pressure  with  a  corresponding  greater  horse  power  for 
the  same  cylinder  dimensions, 


58 


PRINCIPLES  OF  DIESEL  OPERATION 


Four-cycle  Type  (Nelseco). 


PRINCIPLES  OP  DIESEL  OPERATION  59 

In,  addition  to  the  high  thermal  efficiency  of  the  Diesel  engine, 
a  great  commercial  advantage  is  obtained  from,  the  fact  that  the 
cycle  or  method  of  ignition  permits  the  use  of  a  cheap,  low-grade 
fuels  of  high  heat  value;  and  it  has  been  demonstrated  that  all 
petroleums  products,  either  crude  or  refined,  obtained  anywhere,  can 
be  burned  with  high  economy  and  certainty  in  the  same  engine,  by 
merely  changing  some  minor  adjustment  of  the  fuel  injection  mech- 
anism. 

The  designation  of  the  cycle  implies  that  the  work  in  the  cylin- 
der is  accomplished  in  two-cycle  engine  in  two  strokes,  or  a  power 
stroke  every  full  revolution  and  in  the  four-cycle  engine  the  work 
is  accomplished  in  four  strokes  of  'the  piston,  or  two  revolutions 
of  the  engine. 

When  defining  the  action  of  power  development  on  a  four-cycle 
engine  following  procedure  occurs:  The  first  downward  stroke  draws 
into  the  cylinder  pure  air  only  at  atmospheric  pressure  and  temperature. 

The  second  stroke  compresses  this  air  to  about  450  to  600  Ibs., 
per  square  inch  and  increases  its  temperature  to  about  from  1000° 
Fahrenheit  up  to  1150°  F.  depending  upon  the  design. 

On  the  third  or  second  downward  stroke,  a  pre-determined 
amount  of  fuel,  which  has  been  delivered  to  the  fuel  valve  by  the 
pumps  on  the  air  admission  stroke  of  the  engine,  is  forced  into 
the  cylinder  by  means  of  air  compressed  to  a  higher  pressure  than 
that  of  the  air  in  the  cylinders.  The  fuel  is  ignited  by  the  heat 
of  the  compressed  cylinder  charge  and  by  expansion  drives  the  piston 
downward. 

The  fourth  or  second  upward  stroke  drives  the  spent  gases 
out  of  the  cylinders. 

It  will  be  noted  that  while  the  sequence  of  the  strokes  forming 
this  cycle  is  similar  to  that  of  the  gas  engine,  the  functions  per- 
formed during  the  cycle  (except  on  the  exhaust  stroke)  are  entirely 
different. 

On  the  first  stroke,  by  taking  into  the  cylinder  pure  air  only, 
we  are  enabled  to  compress  this  charge  sufficiently  to  secure  a  very 
high  temperature,  which  would  be  impossible  with  a  charge  of  gas 
mixture,  because  of  liability  to  pre-ignition. 

This  high  temperature  secured  allows  the  use  of  cheap,  low- 
grade  fuels  of  high  fire  test,  without  risk  of  explosion,  and  increases 
both  the  thermal  and  commercial  efficiency  of  the  engine. 

On  the  third  stroke  the  fuel  can  be  introduced  under  absolute 
control  as  to  timing  and  quantity,  maintaining  a  constant  pressure  in 
the  cylinder  for  a  period  depending  on  the  work  required  from  the 
cylinder  at  that  moment.  The  use  of  compressed  air  for  injection, 
where  this  system  is  used,  thoroughly  atomizes  the  fuel  and  prepares 
it  for  instant  firing  as  introduced. 


60 


PRINCIPLES  OF  DIESEL  OPERATION 


As  stated  above,  this  combustion  is  not  in  any  sense  an  ex- 
plosion, but  takes  place  during  a  well-defined,  pre-determined  portion 
of  the  power  stroke  and  at  constant  pressure,  and  because  of  the 
nature  of  its  introduction  into  the  cylinder  and  the  large  volume  of 
pure  air  into  which  it  is  forced,  the  combustion  is  perfect  within 
the  range  of  cylinder  power  rating,  hence  the  high  thermal  efficiency 
of  the  Diesel  cycle  on  low  grade  fuels. 

The  foregoing  description  of  the  engine  and  its  cycle  is,  of  course, 
general  in  character — intended  to  cover  the  principles  around  which 
the  physical  construction  is  assembled. 

The  method  of  starting  by  compressed  air  is  to  cause  air  pressure 
through  the  medium  of  independent  compressors  on  larger  engines 
or  in  some  instances  direct  connected  compressors  in  smaller  types, 
to  be  exerted  through  the  assistance  of  a  starting  valve  on  the 
pistons. 

The  process  in  starting  engines  differs  somewhat,  depending 
upon  the  general  construction.  The  usual  proceeding  is  to  bring  the 
starting  lever  in  its  starting  position.  In  doing  so,  the  lever  actuat- 
ing the  fuel  valve  is  brought  in  a  non-operating  position.  In  this 
state  the  fuel  valve  remains  closed  in  its  first  operation. 


Uniform    operation    depend*  greatly  on  accurate  func- 
tioning of  valve-arrangement  actuated  ~by  cams. 


PRINCIPLES  OF  DIESEL  OPERATION 


61 


The  starting  valve  in  performing  its  function  when  opened,  to 
admit  air  to  either  cylinder,  the  engine  begins  to  turn.  When  the 
piston  ^passes  its  dead  center  a  charge  of  oil  is  allowed  to  enter  into 
the  cylinder  causing  a  volume  of  gas  to  be  established  in  the  com- 
bustion chamber. 


Illustration  demonstrating  "Interior  Action"  of  Furl 
being  brought  in  contact   with    heat    temperature. 


It  is  advisable  to  allow  the  engine  to  turn  over  several  revolu- 
tions by  air  to  cause  a  uniform  heating  to  be  created.  This  has 
the  effect  of  causing  an  almost  immediate  combustion  to  take  place 
when  the  starting  handle  is  brought  in  the  respective  position,  allowing 
the  fuel  valve  to  operate  by  its  own  mechanism. 

The  starting  reservoir  having  for  its  object  the  storing  of 
air  for  starting  purposes  should  be  filled  to  its  full  capacity  before 
starting  of  engine.  The  fuel  valve,  which  is  pumped  up  by  hand  before 


62 


PRINCIPLES  OF  DIESEL  OPERATION 


commencing  the  operation  of  the  engine,  and  its  pipe  connections  should 
•be    protperly   filled   with  oil. 

At  all  times  make  sure  that  a  full  supply  of  air  is  on  hand  for 
the  operation  of  the  fuel  valve. 

Proper  operation  of  engine  will  be  the  result  when  following  instruc- 
tions are  carefully  considered:  (1)  Examine  fuel  tanks;  (2)  See  that 
the  lubrication  system  is  properly  functioning;  (3)  Test  the  oil  pump; 
(4)  Test  the  water  pump;  (5)  See  that  all  connections  are  tight;  (6) 
See  that  the  compressor  is  in  proper  working  condition;  (7).  Watch  all 
gauges;  (8)  See  that  seacock  is  open  (on  marine  work);  (9)  Examine 
all  piping;  (10)  'Go  carefully  over  all  parts  of  the  mechanism  and 
examine  all  nuts;  (11)  Try  all  levers;  (12)  If  on  marine  work,  make 
sure  that  the  Annunciator  is  in  proper  operation. 

,  The   functions    of   the    cams    may    be   explained 

in  brief  as  mechanical  arrangements,  having  for 
their  object  the  regulation  of  exact  time  re- 
quired in  opening  of  valves,  relative  to  the  posi- 
tion of  the  piston,  causing  a  regular  functioning 
in  general  operation. 

In  the  action  of  the  four-cycle  engine  it  is 
understood  that  'each  valve  is  required  to  open 
in  two  revolutions,  it  follows  then  that  the  cam 
shaft  must  rotate  at  half  the  speed  of  the  crank- 
s-haft. 

The  cam  operating  the  fuel  valve  performs  its 
function  in  corresponding  period  to  the  piston 
stroke,  depending  upon  established  condition.  The 
exhaust  valve  cam  in  its  relation  to  the  working 
stroke,  allows  the  valve  to  stay  open  during  the 
entire  stroke  and  again  allows  the  exhaust  valve 
to  close  after  the  top  dead  center  has  been  reached. 
The  admission  of  air  is  accomplished  by  the 
valve  being  kept  oipen  admitting  the  air  during 
the  downward  stroke  and  again  closes  after  the 
crank  passes  the  bottom  dead  center. 

The    action    of   the    starting   valve  cam    causes 


::.,'j^ 


Starting  Valve  oj 


Carels    type    used      the  valve  to   open  before   the   top  dead   center  has 
on   Nordberg          been    reached    and    closing    the    same    before    the 


Diesels. 


end  "of  the  stroke. 


INJECTION    OF    FUEL. 

It  will  be  noted,  when  studying  the  different  methods  of  fuel-in- 
jection, that  considerable  difference  in  design  are  to  be  found.  While 
the  trend  appears  to  be  towards  the  solid  injection  system,  nevertheless, 
mechanical  injection  is  prevalent.  It  must  be  acknowledged  that  there 
are  soone  advantages  in  the  use  of  solid  injection.  In  particular  the 
elimination  of  air  as  the  primary  factor  in  forcing  the  oil  into  its 


PRINCIPLES  OF  DIESEL  OPERATION  63 

receptacle.  It  is  true,  that  the>  compressor  is  a  part  of  the  engine 
room  equipment,  Imperative  as  an  auxiliary  machine.  A  Diesel  plant 
without  the  provisioncy  of  air  for  starting  purposes  must  be  dismissed. 
Definition  of  Fuel  Valves:  Generally  speaking,  there  are  two 
types  of  valves  employed  in  the  various  Diesel  engines,  namely  the 
closed  nozzle  and  the  open  nozzle  valves.  While  on  vertical  tyipes  of 
Diesels  the  closed  nozzle  is  principally  used,  owing  to  the  structural 
reasons,  the  open  nozzle  is  prevalent  on  horizontal  engines. 


In  the  "Open  Nozzle"  Spray  Valve,   as   adopted  by   the   Snow   Oil  En- 
gines, the  charges  are  consumed   with   accurate   delivery, 
irrespective  of  load-variation. 


Open  Nozzle  Fuel  Valve:  This  particular  type  of  valve,  or  pro- 
perly speaking,  nozzle,  is  designed  to  -act  as  a  receptacle  wherein  a 
needle  valve  controls  the  flow  of  air  to  the  atomizer  tip.  This  needle 
valve  automatically  opens  to  allow  the  uniform  distribution  of  oil  to 
exist,  depending  in  its  operation  toy  iproper  actuation  of  either  a  cam 
device  or  in  some  types  on  rocker  arm  arrangement.  A  small  cavity 
is  interposed  between  the-  valve  and  the  cylinder,  in  some  cases  an 
enlargement  of  the  passage  to  the  cylinder,  allowing  the  fuel  to  be 
deposited. 

Inasmuch,  as  the  fuel  pump  depends  in  its  entirety  on  the  proper 
governing  to  conform  with  the  desired  quantity  necessary  to  keep  the 
engine  in  regularity  supplied,  the  needle  valve  performs  its  function 
of  opening  and  closing  at  regular  intervals.  When  opening  this  valve 
allows  the  air  at  the  proper  time  from  the  compressor  to  enter,  sweep- 
ing the  oil  charge  along  and  carrying  it  into  the  cylinder.  As  the  oil 
enters  the  extreme  end  of  the  nozzle,  it  is  swirled  by  the  force  of  air 
through  a  set  of  perforated  disks,  serving  to  break  up  the  oil  into  par- 
ticles while  entering  the  combustion  chamber. 

Interior  Action  of  Fuel  Coming  in  Contact  With  High  Temper- 
atures: The  existing  high  temperature  in  the  combustion  chamber  of 
a  normal  value  corresponding  to  550  Ibs.  compression  pressure  should 
be  at  least  1000  deigree  Fahrenheit  xwhen  the  engine  is  on  its  com- 
mencement. The  usual  temperature  on  a  well  designed  engine  when 
in  proper  working  order  and  during  operation  may  be  well  above  1400 


6.  PRINCIPLES  OF  DIESEL  OPERATION 

degrees  Fahrenheit.  Modern  engines  are  well  protected  against  leak- 
ages, and  rarely  any  loss  of  efficiency  is  due  to  this  defect  so  fre- 
quent on  older  types.  With  the  proper  timing  of  the  fuel  injection 
valve  very  little  trouble  will  be  experienced,  it  should  be  realized, 
that  the  change  of  oil,  varying  in  specific  gravities,  necessitates  a 
icareful  observation  and  often  requires  the  retiming  of  valves.  Again 
trouble  may  be  experienced  by  "air-pockets"  in  the  fuel  oil,  caus- 
ing the  lack  of  proper  flow,  which  incidentally  causes  serious  neg- 
lect in  proper  functioning  of  oil  distribution  into  the  cylinder.  Water 
in  oil  causes  carbonizing  and  dangerously  effects  the  efficiency  of  cyl- 
inder performances. 

Closed  Nozzle  Fuel  Valve:  This  type  has  been  used  on  earlier  Die- 
sels. The  advantages  in  employing  the  closed  valve  is,  if  it  may  be  con- 
sidered an  advantage,  that  it  deposits  the  oil  in  a  receptacle  entirely 
isolated  from  the  influence  of  the  hot  compressed  air  in  the  cylinder. 
While  in  this  construction  the  oil  in  reality  enters  the  cylinder  ahead 


Cross-sectional  vieiv  of  Busch-Sulzcr  characteristic     Fuel-Injection     Sys- 
tem.    Note  air-distribution. 


of  the  air,  ignites  and  very  often  endangers  the  efficiency  of  cylinder 
performances  by  entering  without  being  thoroughly  atomized.  This  is 
principally  due  on  account  of  the  initial  charge  entering  under  some- 
what lower  pressure,  preventing  a  thorough  breaking  up  of  the  fuel  oil. 
To  overcome  this  detrimental  defective  existency,  the  employment  of 


PRINCIPLES  OF  DIESEL  OPERATION 


65 


higher  air  pressure  becomes  imperative.  The  fuel  valve,  differing  but 
little  from  the  open-nozzle  type,  with  the  exception  that  the  needle 
valve  is  located  below  the  cavity  in  which  the  atomizing  takes  place 
and  as,  in  similarity  to  the  open-nozzle  valve  in  direct  connection  with 
the  air  line.  Owing  to  its  construction,  by  which  the  fuel  oil  pump 
direct  delivers  the  oil  towards  the  oil  chamber,  the  pressure  necessary 
in  the  a.ir  line  is  usually  no  less  than  900  Ibs.,  per  square  inch.  When 
the  compression  pressure  is  in  the  cylinder  somewhat  around  from 
500  to  550  Ibs.,  per  square  inch  the  needle  valve  opens  and  allows  the 
charge  to  enter.  All  other  performances,  such  as  the  breaking  uip  of  the 
oil  are  similar  to  the  open-nozzle  type. 

Timing  of  Valves:  Timing  of  valves  is  not  very  difficult  as  some 
novices  on  Diesel  machinery  are  apt  to  'believe.  We  will  first  take  up 
the  two-stroke  cycle,  which  by  nature  of  construction  is  the  simplest 
engine. 


Valve  Settings   of  Simple   Port  Scavenging  Two-Cycle 
Engine. 


Timing  Two-cycle  Engine:  The  two-cycle  engine  exerts  a  "power- 
stroke"  every  revolution.  Unlike  the  four-cycle  itype,  using  valves  in  its 
entirety,  the  two-cycle  engine  eliminates  the  air  inlet  stroke  and  the 
exhaust  stroke  and  employs  ports  near  the  bottom  of  the  cylinder  lin- 
er, through  which  the  burnt  gases  are  driven  by  a  current  of  air. 


66 


PRINCIPLES  OF  DIESEL  OPERATION 


The  entering  of  the  air  into  the  cylinders  differs  in  the  various 
types  of  two-cycles.  In  some  engines  it  enters  by  valves  in  the  cylinder 
head  and  others  again  by  ports  similar  and  opposite  the  exhaust  ports, 
and  covered  and  uncovered  by  the  piston.  The  fuel  valve  opens  in 
most  cases  at  5  degrees  before  the  top  center  and  closes  at  42  degrees 
over  the  top  center.  Expansion  occurs  until  the  crank  reaches  a  point 
about  40  degrees  from  the  bottom  center.  At  this  period  the  piston 
uncovers  the  exhaust  ports  near  the  bottom  of  the  cylinder,  allowing 
the  products  of  combustion  to  escape.  About  10  degrees  later  the  air 
inlet  valves,  or  scavenging  valves,  open,  through  which  air  is  blown 
into  the  cylinder,  cleaning  out  the  remaining  burnt  gases,  and  in  con- 
sequence leaving  the  cylinder  full  of  pure  air.  At  40  degrees  over  the 
bottom  center  the  exhaust  ports  are  closed  by  the  piston  on  its  up- 
ward stroke,  and  about  20  degrees  later  the  scavenging  valves  close. 
At  this  period  compression  of  air  begins,  receiving  the  fuel  at  5  de- 
grees before  top  center. 

TIMING  DIAGRAMS 


Fig.  A. 


It  will  l)e  noted  that  in  Figure  A, 
pertaining  to  timing  of  four-cycle 
engine,  that  the  fuel  admission  (a 
part  of  the  cycle  performance),  cor- 
responds with  the  actual  require- 
ment of  engine  performances,  vary- 
ing in  load  capacities. 


Fig.  B. 

On  the  two-cycle  diagram,  Figure 
B,  the  timing  must  correspond  with 
features  demanded  in  two-cycle 
operation,  carrying  with  it  scav- 
enging performances,  again  depend- 
ing mainly  on  load  variations. 


Timing  Four-cycle  Engine:  While  it  is  claimed  that  the  four-cycle 
Diesel  engine  operates  on  the  Otto  cycle,  nevertheless  the  cycle  per- 
formances of  the  Diesel  engine  may  well  be  considered  a  peculiar  and 
'most  distinctive  exclusive  cycle  of  its  own.  The  Diesel  engine  is  a 
"constant  pressure"  engine  and  entirely  separate  in  this  respect  from 
any  other  prime-mover.  We  will  -go  over  the  actual  performances  of 
the  four-cycle  engine  and  follow  its  operation:  All  internal  combus- 
tion engines  depending  for  their  maintenance  upon  four  basic  prin- 
ciples of  performances,  namely,  (1)  Admission,  (2)  Compression,  (3) 
Power  or  Working  Stroke,  and  (4)  Exhaust.  It  is  true,  that  there 
are  two  more  when  scavenging  performances  are  to  be  considered. 


PRINCIPLES  OP  DIESEL  OPERATION  67 

And  it  is  correct  to  add  to  ithose  four  basic  principles,  in  particular  on 
two-cycle  performances  (5)  Air  intake  for  scavenging,  and  (6)  scaveng- 
ing performances.  But  we  are  primarily  interested  in  the  four  standard 
principles  of  operation.  Let  us  carefully  consider  each  (performance. 

First:  On  the  first  downward  stroke  of  the  ycle  air  is  drawn  from 
the  outside  source  into  the  cylinder  through  the  air-inlet  valve. 

Second:  On  its  upward  stroke  the  air  being  compressed  to  the  uni- 
versally known  figure  of  about  500  pounds  per  square  inch.  This  com- 
pression pressure  raises  the  temperature  of  the  air  to  about  1000  de- 
grees Fahrenheit. 

Shortly  before  the  end  of  the  stroke,  fuel  oil  is  injected  into 
the  place,  known  as  the  combustion  chamber.  This  place  is  identi- 
cal with  the  clearance  space  of  a  steam  cylinder,  namely,  the  space  be- 
tween the  piston  face  and  the  cylinder  head.  Piston  (on  the  vertical) 
being  on  its  upward  stroke,  and  on  the  horizontal  on  the  outward  stroke. 
This  oil,  now  coming  in  direct  contact  with  the  existing  high  temperature, 
begins  to  burn — causing  the  combustible  substance  which  follows  the 
laws  of  least  resistance,  which,  being  exerted  against  the  piston,  causes 
the  reciprocation  with  the  consequential  results  of  revolution  of  the 
engine. 

Third:  As  previously  explained,  the  number  three  stroke  is  the 
most  important,  the  power  or  working  stroke.  The  fuel  on  the  commence- 
ment of  this  stroke  is  cut  off  at  about  1/10  of  the  stroke,  combustion 
having  taken  place,  with  the  expansion,  which  follows  near  the  end 
of  the  stroke,  the  exhaust  valve  opens. 

Fourth:  This  stroke  merely  causes  the  burned  gases  to  be  ex- 
pelled, after  which  the  cycle  of  operations  is  repeated. 

We  will  now  follow  the  actual  work  taking  place  during  the  power 
generation.  Inasmuch  as  the  four-cycle  engine,  gives  two  revolutions 
of  the  crank,  or  four  strokes  to  a  cycle,  the  power  exertion  of  founcyfcle 
engines  is  a  power  stroke  every  second  revolution.  In  most  engines  the 
air  inlet  valve  opens  20  degrees  before  the  top  center,  and  closes  16 
degrees  after  bottom  center,  giving  a  total  angular  opening  of  216  de- 
grees of  the  crank.  Immediately  after  the  air  inlet  valve  is  closed,  the 
air  is  compressed  until  a  point  about  5  degrees  before  the  top  center 
is  reached.  Admission  of  fuel  now  commences,  continuing  until  the 
crank  is  40  degrees  over  top  center,  giving  the  fuel  valve  an  angular 
opening  of  45  degrees. 

As  the  gases  expand,  forcing  the  piston  down  until  34  degrees  before 
the  bottom  "enter,  the  exhaust  valve  opens  and  the  products  of  com- 
bustion are  released  and  then  expelled  by  the  fourth  stroke,  or  the  up- 
ward stroke,  of  the  piston.  The  exhaust  valve  closing  11  degrees  after 
the  top  center. 

Mechanical  Timing  of  Valves:  To  accurately  ascertain  the  mech- 
anical timing  arrangement  of  valves,  it  is  best  to  time  each  cylinder  in 
rotation.  Begin  to  time  the  exhaust  and  admission  valve  on  front 
cylinder  and,  when  all  marks  have  been  properly  made,  corresponding 


68  PRINCIPLES  OF  DIESEL  OPERATION 

to  the  flywheel,  follow  the  exact  measurement  on  eac'i  corresponding 
cylinder. 

To  establish  the  flywheel  'position,  bringing  it  in  the  proportional 
requirement  corresponding  to  upper  dead  center  of  the  crank  should  be  the 
first  step.  The  valve  cages  can  then  be  removed,  and  the  distance  from 
the  surface  of  the  cylinder  head  to  the  piston,  establishing  the  clear- 
ance, can  be  properly  determined.  When  this  has  'been  established 
mark  flywheel.  If  trammel  is  used,  be  careful  in  finding  the  retangular 
advance  of  the  crank  on  its  upward  stroke,  by  which  the  numerical 
opening  and  closing  of  each  valve  gives  an  accurate  idea.  A  steel 
tape  may  be  used  to  bring  the  opening  of  exhaust  valve  to  a  point  of 
correctness.  Since  the  timing  given  is  in  degrees,  the  value  must  be 
transformed  into  inches  on  the  flywheel  circle. 

The  exhaust  cam  rocker  must  be  firmly  brought  in  contact  both  with 
the  cam  and  with  the  valve  stem.  After  the  mark  on  the  top  dead  cen- 
ter of  crank  ha/5  been  thoroughly  established,  turn  engine  over  at  least 
12  degrees  to  make  positive  that  the  correct  seating  of  valve  has  been 
accomplished.  If  undue  valve  checking  is  experienced,  the  operator 
should  carefully  examine  the  setting.  If  the  irregularity  does  not  ex- 
ceed a  few  inches  on  trammel  mark  on  flywheel,  the  clearance  between  the 
valve  rocker  and  the  cam  .may  be  adjusted  bringing  the  setting  back  to 
the  stated  values.  To  the  man  inexperienced  it  is  best  to  allow  a  little 
clearance,  adjusting  the  cam  on  earlier  or  later  cut  off,  after  being  thor- 
oughly convinced  that  the  exhaust  charges  show  an  excessive  smoke.  At 
all  times  follow  the  exact  routine  in  following  manner:  The  exhaust 
opening  of  number  1  will  be  set;  the  admission  closing  of  a  second 
cylinder  will  be  checked.  It  will  be  noted,  that  in  case  any  irregularity 
exists,  the  fault  may  be  detected  by  a  peculiar  pounding  in  the  cylinder 
after  engine  is  in  motion.  On  marine  engines,  valves  should  be>  pro- 
perly adjusted  and  all  care  taken  that  the  tightness  of  the  same  are 
accomplished. 

It  is  necessary  in  operation  of  Diesels  that  the  injection  air  pres- 
sure 'be  altered  to  conform  to  load  changes.  It  is  clear  that  with  load 
changes  the  time  during  which  the  fuel  is  injected  should  also  vary. 
On  low  loads  the  amount  of  fuel  oil  is  small  and  will  be  entirely  blown  into 
the  cylinder  long  before  the  valve  closes.  The  balance  of  this  period  of 
valve  opening  is  taking  up  with  the  injection4iigh-<pressure  air.  All 
these  calculations  are  imperative  in  successful  operation  and  requires 
careful  observation. 

Cleaning  Valves:  To  maintain  efficiency  and  avoidance  of  break- 
downs, the  inspection  of  valves  must  be  made  a  matter  of  routine  work. 
At  least  every  month  each  valve  and  cage  should  be  given  a  thorough 
overhauling.  Spare  parts  should  be  at  hand  and  a  reserve  set  of  valves 
should  never  be  neglected.  When  the  old  valves  are  taken  off  the  engine 
and  substituted  by  a  reserve  valve,  it  should  be  taken  apart  and  in- 
spected. Keeping  foreign  matter  from  settling,  around  the  seats  and 
springs  by  giving  them  a  bath  in  gasoline  is  imperative. 


PRINCIPLES  OF  DIESEL  OPERATION 


Occasional  grinding  of  valves  becomes  necessary.  In  particular  in 
cases  where  the  fuel  contains  high  percentages  of  asphalt  or  sulphur. 
Corrosion  and  pitting  are  primary  causes  of  leakage.  Chemical  action 
of  the  exhaust  gases  rapidly  deterriorates  the  material  with  increased 
faulty  action  of  the  entire  unit.  Every  part,  no  matter  how  insignifi- 
cant is  in  harmony  with  the  plant,  and  the  neglect  of  even  the  smallest 
parts  of  the  engine,  may  cause  serious  breakdowns. 


Valve  Spindle. 


Sprayer. 


Timing  of  Fuel  Valves:  The  timing  of  fuel  valves  depends  a  great 
deal  on  the  particular  make.  While  different  designs  are  forthcoming 
as  Diesel  machinery  progresses,  nevertheless  the  common  procedure  is 
as  follows:  Turn  engine  over  until  it  passes  the  desired  mark  of  fuel 
valve  opening.  The  air  line  valve  is  "cracked,"  at  about  75  pounds  air 
pressure  on  the  fuel  valve.  The  engine  now  being  turned  over  slowly 
until  the  trammel  cuts  the  mark  on  the  flywheel  signifying  opening. 
At  this  time  the  injection  valve  should  start  to  open,  which  may  be 
evidenced  by  the  sound  of  injection  air  blowing  into  the  cylinder.  The 
decrease  or  increase  of  valve  opening,  may  "be  adjusted  on  the  rocker 
arm  clearance,  depending  upon  the  desired  position  of  the  valve  arrange- 
ment. When  the  engine  is  brought  to  its  proper  position  corresponding 


70  PRINCIPLES  OF  DIESEL  OPERATION 

to  fuel  valve  adjustment,  it  should  be  noticed  by  the  ceasing  of  es- 
caping air.  To  bring  the  adjustment  in  accurate  desired  valve  operation, 
it  will  be  found  necessary  to  turn  the  engine  back  after  the  -point  of 
"cut-off"  has  been  determined.  Bring  the  engine  back  ahead  of  the 
valve  opening  mark  and  shift  the  cam  nose  to  produce  the  required 
opening  with  the  roller  clearance  in  correct  position.  To  ascertain 
the  correct  setting  after  the  checking  has  been  performed,  it  is  re- 
commended to  give  the  engine  several  turns.  It  will  be  noticed  that 
the  difference  in  adjustment  of  either  early  or  late  may  be  caused  by 
shifting  the  nose  back  or  forth  as  the  case  may  be,  which  will  have  an 
effect  on  the  roller  clearance,  tending  to  'bring  the  valve  to  its  desired 
correctness. 

The  equipping  of  Fuel  Valve  Timing  Control,  adopted  by  Standard 
firms,  such  as  the  Busch-Sulzer,  Nordberg-Manufacturing  Company,  etc. 
by  which  the  alteration  of  injections  automatically  takes  place,  elimi- 
nates a  great  deal  of  complications  found  on  the  usual  types. 


TENSILE    STRENGTHS    OF    MATERIALS 
Cast  and   Rolled   Metals. 
Pounds  per  Square  Inch. 

Aluminum,   Cast    15,000 

Aluminum,   Bars   28,000 

Brass,  Cast,  Yellow 27,000 

Brass,  Rod 55,000 

1"  and  below..  __62,000 


Brass,  Rolled,  Naval  . 

Above  1"  to  2^" 60,000 

Bronze,  Cast,  Steam  30.000-36,000 

Bronze,    Cast,    Manganese 65,000 

f  1"  and  below 72,000 

Bronze,  Rolled  Manganese.- 

L  Above  1"   70,000 

Bronze,  Cast,   Phosphor 30,000-40,000 

(y2"  and  below 80,000 

Bronze,    Rolled,    Phosphor J  A'bove  y2"  to  1" 60,000 

[Above  1"   55,000 

TLighit  castings   18,000 

Iron,  Cast,  Grey J  Medium  castings 21,000 

[Heavy  eastings 24,000 

Iron,    Malleable    40,000 

Iron,   Wrought   (Shapes..       48,000 


PRINCIPLES  OF  DIESEL  OPERATION 


71 


Lead,  Cast 1,600-  2,400 

Monel,  Cast 65,000 

fl"  and  below 84,000 

Monel,  Rolled  _  ._J  Above  1"   to  2^" j 80,000 

L Above    2^" 75,OOG 

Nickel,  Cast  ; 85,000 

Nickel,  Rolled  96,000 

("Hard  80,000 

Steel,  Cast J  Medium  70,000 

[soft   60,000 

Steel  Forgings  75,000-90,000 

Steel,  3.5%   Nickel  100,000-105,000 

Tin,    Cast    4,000-5,000 

Zinc,   Cast  _  4,000-  6,000 


STRENGTH  OF  MATERIALS 


(Stresses  in  Thousands  of  Pounds) 


Metals  and  Alloya 


Aluminum,  cast 
Copper,    cast 
Brass,  17%  Zn 

Brass,  cast,  common 18-24 

Bronze,   8%   Sn 

Lead,   cast 

Tin,  cast 3.5-4.6 

Zinc,  cast 
Steel,    cast,    soft 
Steel,   cast,   medium 
Steel,    cast,   hard 

Cast  Iron,  common 15-18 

Nickel   Steel,   plate 85-100 

Wrought  Iron,  plate 
Gold,  cast 
Silver,   cast   _ 


Tension 
Ultimate 

Elastic     ( 
Limit 

Compression 
Ultimate 

Modulus  of 
Elasticity 
Pounds 

15 

6.5 

12 

11,000,000 

25 
32.6 

6.0 

8.2 

40 
42 

10,000,000 

18-24 

6.0 

30 

9,000,000 

28.5 

19.0 

42 

10,000,000 

1.8 



__ 

1,000,000 

3.5-4.6 

1.5-1.8 

6 

4,000,000 

4-6 

4 

18 

13,000,000 

60 

27 

tensile 

29,000,000 

70 

31.5 

tensile 

29,000,000 

80 

36 

tensile 

29,000,000 

15-18 

6 

80 

12,000,000 

85-100 

50 

tensile 

29,000,000 

48 
20 

26 
4 

tensile 

28,000,000 
8,000,000 

40 

72  PRINCIPLES  OF  DIESEL  OPERATION 

EXPANSION    OF    PIPES 

The  linear  expansion  and  contraction  of  pipe,  due  to  differences  of 
temperature  of  the  fluid  carried  and  the  surrounding  air,  must  be  cared 
for  by  isuitable  expansion  joints  or  bends. 

In  order  to  determine  the  amount  of  expansion  or  contraction  in  a 
pipe  line,  following  table  demonstrates  the  increase  in  length  of  a  pipe 
100  feet  long  at  various  temperatures. 

The  expansion  for  any  length  of  pipe  may  be  found  by  taking  the 
diference  in  increased  length  at  the  minimum  and  maximum  tempera- 
tures, dividing  by  100  and  multiplying  by  the  length  of  the  line  under 
consideration. 


Expansion  of  Pipe 

Increase  in  Length — Inches  per  100  Feet. 

Temperatures,                                                 Wrought  Cast          Brass  and 

Degrees   F.  Steel  Iron  Iron  Copper 

0    0000 

20    .__  .15                   .15  .10  .25 

40    ___  .30                   .30  .26  .45 

60  _                                ___  .45                   .45  .40  .65 

80    .60                   .60  .55  .90 

100    ___  .75                   .80  .70  1.15 

120 .90                   .95  .85  1.40 

140    ___  1.10  1.15  1.00  1.65 

160    1.25  1.35  1.15  1.90 

180    1.45  1.50  1.30  2.15 

200    ___  1.60  1.65  1.50  2.40 

220    _                        1.80  1.85  1.65  2.65 

240    2.00  2.05  1.80  2.90 

260    ___  2.15  2.20  1.95  3.15 

280    ___  2.35  2.40  2.15  3.45 

300    2.50  2.60  2.35  3.75 

320    2.70  2.80  2.50  4.05 

340    __..  2.90  3.05  2.70  4.35 

360    3.05  3.25  2.90  4.65 

380    3.25  3.45  3.10  4.95 

400    3.45  3.65  3.30  5.25 

420    3.70  3.90  3.50  5.60 

440    3.95  4.20  3.75  5.95 

460  _                                ___  4.20  4.45  4.00  6.30 

480    4.45  4.70  4.25  6.65 

500    ___  4.70  4.90"  4.45  7.05 

520    '___  4.95  5.15  4.70  7.45 

540    ___  5.20  5.40  4.95  7.85 

560  -                                ___  5.45  5.70  5.20  8.25 

580    ___  5.70  6.00  5.45  8.65 

600  .                                   _  6.00  6.25  5.70  9.05 


PRINCIPLES  OF  DIESEL  OPERATION  73 

Temperatures,  Wrought  Cast  Brass  and 

Degrees   F.                               .  Steel  Iron  Iron  Copper 

620    6.30  6.55  5.95  9.50 

640 6.55  6.85  6.25  9.95 

660    _                                ---  6.90  7.20  6.55  10.40 

680    7.20  7.50  6.85  10.95 

700    —  7.50  7.85  7.15  11.40 

720    7.80  8.20  7.45  11.90 

740    ___  8.20  8.55  7.80  12.40 

760    ___  8.55  8.90  8.15  12.95 

780    ___  8.95  9.30  8.50  13.50 

800    .                                    -  9.30  9.75  8.90  14.10 


CHAPTER  V. 

LIQUID  SUBSTANCES 
SPECIFIC    HEAT 

Bodies  vary  greatly  in  the  capacity  which  they  possess  for  absorb- 
ing heat  under  equal  changes  in  temperature.  The  relation  which  thus 
exists  between  them  is  expressed  by  the  "specific  heat,"  which  may  be 
defined  ais  the  quantity  of  heat  necessary  to  be  imparted  to  a  given  body 
in  order  to  raise  its  temperature  one  degree  relatively  to  the  quantity 
that  is  required  to  raise  through  one  degree  an  equal  weight  of  water 
from  its  point  of  greater  density  at  39.1°.  Thus,  for  instance,  one  pound 
of  air  at  constant  pressure  may  be  raised  through  one  degree  by  the 
expenditure  of  only  0.2375  of  the  heat  necessary  to  raise  one  pound  of 
water  through  one  degree;  or,  what  amounts  to  the  same,  the  amount 
of  heat  expended  to  raise  the  temperature  of  one  pound  of  water  by  one 
degree  (would  heat  1/0.2375  =  4.2105  pounds  of  air  through  the  same 
increment. 

As;  the  specific  heat  of  water  is  greater  than  that  of  any  other 
known  substance,  the  specific  heat  of  all  other  substances  must  of  neces- 
sity be  expressed  in  decimals. 

Water  does  not  absorb  heat  exactly  in  proportion  to  its  increase  in 
temperature;  in  other  words,  the  specific  heat  of  water  varies  with  the 
temperature,  as  is  rendered  evident  in  the  following  table. 


SPECIFIC  GRAVITY 

Water  is  universally  adopted  as  the  standard  'by  which  the  relative 
weight  of  all  liquids  and  solids  are  determined,  this  relation  being  ex- 
pressed iby\  the  term  of  "sipecific  gravity."  The  specific  gravity  of  a 
body,  therefore,  indicates  its  weight  as  compared  with  that  of  an  equal 
body  in  the  form  of  volume  of  pure  water,  determinations  of  specific 
gravity  are  generally  referred  to  the  weight  of  one  cubic  foot  of  water 
at  62  degrees  Fahrenheit.  At  the  more  important  temperatures  the 
weight  is  as  follows : 

Weight  of  one  cubic  foot  of  pure  water: 

At  32  degrees  F.  (freezing  point) 62.418  Ibs. 

"    39.1       "        "    (maximum  temperature) 62.425     " 

"    62         "        "    (standard   temperature)    62.355     " 

"  212        "        "    (boiling    point    under    atmospheric 

pressure  59.760     " 


LIQUID  SUBSTANCES  75 

For  general  purposes  the  weight  of  water  is  taken  in  round  num- 
bers as  62.5  pounds  per  cubic  foot.  In  bulk,  water  is  usually  measured 
by  the  gallon,  the  volume  of  which  is  231  cubic  inches  (the  British 
gallon  contains  277.274  cubic  inches),  or  0.134  cubic  feet.  A  gallon  of 
water  at  62  degrees,  therefore,  weighs  slightly  over  8  and  1/3  pounds, 
and  7.48  gallons  equal  one  cubic  foot. 


PRESSURE    OF    WATER 

From  the  weight  of  water  at  the  standard  'temperature  of  62  de- 
grees, its  pressure  upon  any  exposed  surface  may  be  readily  determined 
for  any  given  depth  or  head.  The  weight  of  one  cubic  foot  at  the  above 
temperature  being  62.355  Ibs.,  it  is  evident  that  for  a  head  of  one  foot 

62.355 

the  pressure  must  be  62.355  Ibs.  per  square  foot,  and  —       —  =  0.433  Ibs. 

144 

per  square  inch;   and,  further,  that  a  pressure  of  one  pound  per  square 

1 

inch  will  be  produced  by  a  head  of  -    —  =  2.309  feet. 

0.433 


OIL    MEASUREMENTS 

For  the  calculation  of  evaporative  results,  fuel  used  for  power,  heat 
value,  etc.,  units  of  weights  are  employed,  i.  e.,  the  pound,  kilo,  etc. 
(1  kilo  =  2.204  'pounds  avoirdupois);  but  for  measurements  of  bunkers, 
cargo  tanks  and  in  general  sales  contracts,  the  oil  is  figured  by  volume. 
Thus,  in  the  United  States,  the  usual  units  are  the  United  States  gallon 
(231  cubic  inches  =  3.785  litres)  and  the  barrel  of  42  gallons. 

The  litre  and  the  Imperial  gallon  (4.54  litres)  are  used  abroad, 
where  the  barrel  is  figured  at  41  Imperial  gallons  (50  United  States 
gallons).  The  Imperial  gallon  equals  about  1.2  United  States  gallons. 
Even  some  of  American  oil  ifirms  favor  the  Imperial  barrel  (50  United 
States  gallons)  as  a  matter  of  convenience,  -but  42  gallons  is  the  ac- 
cepted standard. 

For  .statistical  purposes,  the  ton  (2,240  pounds)  and  the  "metric 
ton"  or  1,000  kilos  (2,204  pounds)  are  frequently  used. 

Volumetric  measurement  of  oil  should  always  be  based  on  a  standard 
temperature,  the  usual  figures  in  this  country  being  62  degrees  Fahren- 
heit. The  United  States  Navy  Department  specifies  60  degrees  Fahren- 
heit and  a  correction  of  0.4  of  1%  is  made  for  each  degree  variation 
from  this  standard. 

MECHANICAL    EQUIVALENT    OF    HEAT 

The  mechanical  unit  of  work  is  the  "foot-pound,"  or  the  work  re- 
quired to  raise  one  pound  through  the  distance  of  one  foot.  The  me- 


76  LIQUID  SUBSTANCES 

chanical  theory  of  heat  regards  heat  as  a  mode  of  motion,  an  investiga- 
tion has  shown  that  there  exists  a  definite  relation  between  these  two 
forms  of  energy,  which  is  known  as  the  "mechanical  equivalent"  of  heat. 
That  is,  if,  as  in  the  experiments  of  Joule,  a  certain  known  amount  of 
mechanical  energy  is  expended  (as  by  falling  of  a  weight)  to  operate 
paddles  in  a  vessel  of  water,  the  increase  in  temperature  of  the  water, 
due  to  agitation  by  the  paddles,  will  always  'be  found  to  be  proportional 
to  the  work  done. 

This  relation  or  proportion  is  universally  expressed  by  the  amount 
of  work  necessary  to  raise  the  temperature  of  one  pound  of  water 
through  one  degree  Fahrenheit.  The  latest  experimental  determinations 
of  Rowland  show  it  to  be  practically  778  foot-pounds. 


%HEAT   OF  COMBUSTION: 

As  determined  by  the  most  recent  and  refined  calorimetric  tests, 
the  heat  of  combustion,  as  measured  by  the  number  of  B.  T.  u.'s  that 
are  given  out  upon  the  combustion  of  one  pound  of  a  given  substance, 
is  for  each  of  the  following: 

Carbon  burned  to   CO-'   14,650   B.   T.   U. 

Carbon   burned   to    CO 4,400  B.  T.  U. 

Hydrogen  burned  to  CO 62,100  B.  T.  U. 

Marsh  Gas  burned  to  CO 23,513  B.  T.  U. 

Olefiant  Gas  burned  to  CO  21.343  B.  T.   U. 

Carbonic  Oxide  burned  to  CO-'  _  __4,393  B.  T.  U. 


BEAUME  HYDROMETER  SCALES 

Various  arbitrary  scales  of  equal  parts  have  been  proposed  for 
hydrometers.  Of  these  scales  those  of  Beaume  are  most  extensively 
used.  Beaumes  scale  for  heavy  liquids  is  constructed  by  locating  the 
water  mark  (near  the  top  of  the  stem)  and  the  mark  to  which  the  in- 
strument sinks  in  •  a  15%  solution  of  salt.  The  apace  between  these 
marks  is  divided  into  ten  equal  parts,  and  division  of  like  sizes  are 
continued  up  the  stem. 

These  divisions  are  numbered  upwards  from  the  salt  solution  mark. 
A  liquid  is  said  to  have  a  specific  gravity  of  17  degree  Beaume  "light", 
when  the  hydrometer  sinks  in  it  to  mark  number  seventeen  on  this 
scale. 


THE    CALORIMETER 

The  apparatus  employed  in  the  measurment  of  the  heat  of  vapo- 
rization is  a  calorimeter,  containing  a  hollow  spiral  and  inner  recept- 
acle. Vapor  is  sent  into  the  spiral,  where  it  is  condensed,  and  the 
liquid  thus  produced  gathers  in  the  receiver,  whence  it  is  subse- 
quently removed  and  weighed.  The  liquid  heated  in  the  vessel,  whence 


LIQUID  SUBSTANCES  77 

the  vapor  passes  through  the  inner  tube  to  the  spiral.  Here  it  con- 
denses, warming  the  surrounding  water  of  the  calorimeter  and  is  col- 
lected in  the  receptacle. 

VISCOSIMETRY 

The  term  viscosity  represents  the  internal  friction  of  an  oil;  it 
is  the  opposite  of  fluidity.  It  is  usually  determined  by  noting  the  time 
in  seconds  required  for  a  definite  quantity  of  oil  to  flow  through  cylin- 
drical or  conical  openings,  approximately  0.50  to  0.75  in.  in  length  and 
0.01  in.  in  diameter.  The  name  or  type  of  instrument  used  and  the  tem- 
perature should  always  be  given  in  expressing  viscosities  numerically. 

The  viscosities  of  two  oils  can  be  roughly  compared  as  follows: 
Two  sample  bottles  containing  the  oils  are  held  side  by  side  and  in- 
verted. The  oil  that  drops  from  its  bottle  first  has  a  lower  v'scosity  than 
the  other  oil.  Another  crude  method  of  comparing  viscosities  is  to  shake 
the  sample  bottles  of  the  oils  and  then  to  note  the  rise  through  the  oils 
of  approximately  equal  size  air  bubble.  The  faster  the  movement  of  the 
bubble,  the  lower  the  viscosity  of  the  oil. 

A  rough  quantitive  comparison  can  be  obtained  by  filling  a  clean 
pipette  with  about  10  cu.  cm.  of  the  oil  and  counting  the  seconds  re- 
quired for  the  oil  to  flow  from  one  mark  on  the  upper  stem  of  the  pipette 
to  another  mark  on  the  lower  stem.  Thereupon  the  pipette  is  cleaned 
with  ether,  dried,  filled  with  the  second  oil  and  the  experiment  repeated. 
If  the  time  of  flow  in  seconds  for  one  oil  is  one-half  that  of  the  other, 
the  first  oil  has  roughly  one-half  the  viscosity,  provided  the  temperatures 
of  both  oils  during  the  test  are  the  same.  In  order  to  'be  sure  that  both 
oils  are  at  the  same  temperatures,  they  should  be  placed  in  beakers  and 
left  to  stand  side  by  side  on  a  table  for  about  one  hour  before  the  test 
is  made. 

For  accurate  results  practical  viscosimeters  must  'be  used.  These 
instruments  combine  ruggedness  of  construction  with  rapidity  of  opera- 
tion and  work  on  the  principle  of  permitting  a  small  quantity  of  the 
liquid  to  flow  through  an  orifice  and  noting  the  time  of  efflux. 

Among  the  instruments  in  commercial  use  are  the  Engler  Viscosi- 
meter,  which  is  specified  for  U.  S.  Navy  fuel  oil  tests  and  is  the  stand- 
ard instrument  in  Germany; the  Sayboldt  Universal  Viscosimeter  which 
is  in  general  use  in  the  United  States;  and  the  Redwood  Viscosimeter, 
the  standard  instrument  in  England.  These  will  now  toe  briefly  des- 
cribed. 

Engler  Viscosimeter:  The  Engler  Viscosimeter  consists  of. a  cylin- 
drical oil  chamber  provided  with  a  concave  bottom  in  the  center  of 
v/hich  is  a  conical  orifice,  20  mm.  (0.78  in.)  in  length  and  2.9  mm.  (0.114 
in.)  in  diameter  at  the  top  of  the  orifice.  This  diameter  tapers  to  2.8  mm. 
(0.110  in.)  at  the  bottom  of  the  orifice.  For  standard  work,  the  orifice 
is  made  of  platinum,  but  ordinarily  brass  is  used.  The  oil  chamber  is 
covered  with  an  asbestos  lagged  lid. 

A  plug  valve  made  of  hard  wood  is  used  as  stopper  for  the  orifice. 


78  LIQUID  SUBSTANCES 

The  oil  chamber  is  made  of  brass  and  on  the  inside  is  provided  with  three 
studs  in  a  horizontal  plane.  These  studs  serve  both  to  indicate  the 
proper  oil  level  and  to  assist  in  leveling  the  instrument. 

Surrounding  the  oil  chamber  is  a  water  bath.  Water  is  used  for 
temperatures  up  to  about  120°  Fahr.  (about  50°  C.)  Above  this  tempera- 
ture a  heavy  mineral  oil  is  used  instead  of  the  water.  The  bath  is  heated 
by  means  of  a  ring  gas  burner. 

Immediately  below  the  oil  tube  outlet  is  a  measuring  flask  graduated 
for  100  and  200  cu.  cm,  (6.1  and  12.2  cu.  in.  ). 

The  method  of  use  is  as  follows:  200  cu.  cm.  of  water  at  68°  Fahr. 
(20°  Gels.)  are  permitted  to  flow  through  the  orifice  and  the  time  in 
seconds  is  counted.  In  the  standard  instrument  this  is  50  to  53  seconds. 
Thereupon  the  oil  chamber  is  rinsed  with  alcohol,  then  ether,  and  finally 
dried.  200  cu.  cm.  of  oil  are  introduced  and  brought  -to  the  proper  tem- 
perature. Before  introducing  the  oil,  it  should,  be  strained  in  order  to 
remove  foreign  particles,  dirt  and  water.  The  oil  is  then  allowed  to 
flow  through  the  orifice,  and  the  time  of  flow  noted.  Suppose  this  is 
360  seconds  at  122°  Fahr.  (50°  C.)  and  that  the  time  of  flow  for  200 
cu.  cm.  of  water  at  68°  F.  (20°  C.)  is  53  seconds,  then: 

Engler  viscosity  at 

360 

122°  Fahr.   (50°  C.)  =  -  -  =  6.8 

53 

If  the  oil  had  been  tested  at  302°  Fahr.  (150°  Gels.)  and  the  time 
noted  as  90  sec.,  the  viscosity  would  be: 

Engler  viscosity  at 

90 

302°  Fahr.   (150°  Gels.)  =  -  -  —  1.7 

53 

In  other  words,  with  this  instrument,  a  'specific  vicosity,  which  of 
course  is  a  purely  arbitrary  number,  is  obtained  by  dividing  the  time  in 
seconds  required  for  200  cu.  con.  of  oil  at  any  temperature  to  flow  through 
the  orifice  'by  the  time  in  seconds  required  for  200  cu.  cm.  of  water  at 
68°  Fahr.  (20°  Gels.)  to  flow  through  the  same  orifice. 

50  cu.  cm.  or  100  cu.  cm.  are  frequently  employed  instead  of  200 
cu.  cm.  However,  the  times  of  flow  must  then  be  multiplied  by  5  and 
2.35  respectively  in  order  to  obtain  results  concordant  with  those  deter- 
mined in  the  ordinary  way. 

Redwood  Viscosi meter:  The  'Redwood  Viscoslmeter  consists  of  a 
cylindrical  oil  chamber  of  1  7/8  in.  internal  diameter  and  3  1/2  in.  depth. 
The  oil  chamber  is  made  of  copper,  silvered  on  the  inside  and  has  a 
slightly  concave  bottom  in  the  center  of  which  is  an  agate  jet  or  orifice 
13  mm.  (0.47  in.)  in  length  and  1.7  mm.  (0.067  in.)  in  diameter. 

Surrounding  the  oil  cylinder  is  the  bath  container  made  of  copper 
and  usually  filled  with  water  for  temperature  up  to  200°  Fahr.  F"or  higher 


LIQUID  SUBSTANCES  79 

temperatures,  a  heavy  mineral  oil  is  used.  The  bath  is  provided  with  a 
copper  heating  tube  set  at  a  45°  angle  and  heated  by  a  suitable  gas  burner. 
Uniform  temperature  is  maintained  in  the  'bath  by  means  of  agitators  or 
stirrers  consisting  of  four  light  metal  vanes  fastened  to  a  thin  copper 
tube  revolving  around  the  oil  chamber.  The  upper  /part  of  this  copper 
tube  has  a  broad  curved  flange  which  prevents  the  bath  liquid  from 
splashing  into  the  oil  chamber.  The  agitators  are  revolved  by  means  of 
a  handle. 

The  temperatures  of  both  the  oil  and  bath  are  determined  by  means 
of  suitable  thermometers  suspended.  The  oil  chamber  stopper  is  a  brass 
sphere  which  fits  nicely  into  a  hemispherical  cavity  in  the  agate  jet. 
The  brass  ball  is  suspended  by  a  wire. 

A  bracket  gage  or  pointed  stud  determines  the  initial  head  of  oil 
in  the  oil  chamber  and  can  be  adjusted  slightly  in  order  to  correct  for 
variations  in  time  of  flow  between  different  instruments  due  to  unavoid- 
able differences  in  the  dimensions  of  the  agate  jets  of  Redwood  Viscosi- 
meters.  A  determination  is  made  by  bringing  the  oil  and  bath  to  the 
proper  temperature,  raising  the  ball  valve  and  noting  the  time  in  seconds 
for  50  cu.  cm.  of  the  oil  to  pass  through  the  jet.  The  viscosity  is  found 
as  follows: 

Redwood  viscosity  at 

T  X  D   X   100 
X°  P.  =  - 

535  X   0.915 

in  which 

T  =  the  time  in  seconds  required  for  50  cu.  cm.  of  oil  at  X°  F.  to 
flow  through  the  orifice. 

D  =  the  specific  gravity  of  the  oil  at  X°  F. 

535  =  the  time  in  seconds  required  for  50  cu.  cm,  of  refined  raipe- 
seed  oil  at  60°  Fahr.  to  flow  through  the  orifice. 

0.915  =  the  specific  gravity  of  rape-seed  oil  at  60°  Fahr.  referred 
to  water  at  60°  Fahr.  as  unity. 

For  water,  the  rate  of  flow  of  50  cu.  cm.  at  60°  F.  is  about  25.5 
seconds.  Before  being  used  in  the  instrument,  the  oil  should  be  strained 
through  a  fine  wire  gauze  or  piece  of  muslin. 

Sayboldt  Viscosimeter:  With  the  exception  of  two  glass  windows 
in  the  bath  container  and  a  glass  tube  in  the  pipette,  the  Sayboldt  Vis- 
cosimeter is  made  entirely  of  metal.  The  oil  chamber  or  cylinder  has 
about  83  cu.  cm.  (5.05  cu.  in.)  capacity  and  the  upper  portion  of  the 
cylinder  is  perforated  by  a  ring  of  small  holes  through  which  excess  oil 
flows  into  a  fixed  gallery. 

The  jet  in  the  bottom  of  the  cylindrical  oil  chamber  consists  of  an 
outside  metal  tube  within  which  is  a  glass  tube.  At  the  bottom  of  this 
tube  is  the  orifice,  9  mm.  (0.354  in.)  in  length  and  1.6  mm.  (0.063  in.) 
in  internal  diameter.  On  the  outside  of  the  metal  tube  is  a  flange  which 


80  LIQUID  SUBSTANCES 

is  secured  by  screws  to  a  flange  on  a  short  tube  soldered  to  the  bottom 
of  the  bath  container. 

Thermomters  are  provided  for  measuring  the  temperatures  of  the  oil 
and  the  'bath.  The  viscosity  is  determined  by  noting  the  time  in  seconds 
required  for  60  cu.  cm.  of  liquid  to  flow  through  the  orifice.  For  water 
at  70°  Fahr.  this  is  30  sec.  in  a  standard  instrument. 

'Sayboldt  viscosity  tests  are  generally  made  at  the  following  tem- 
peratures : 

210°   Fahrenheit  for  valve   oils. 

100°  Fahrenheit  for  machine  oils. 

100°  Fahrenheit  for  motor  oils  used  in  internal  combustion  engines. 

Sayboldt  viscosities  may  be  converted  into  Engler  and  Redwood 
viscosities,  and  also  into  readings  of  other  instruments  by  means  of  the 
factors  given  in  following  table: 


FACTORS  TO   REDUCE  SAYBOLDT  TIMES  TO   READINGS  IN  OTHER 

INSTRUMENTS 

Viscosimeter  70°  F.  100°  F.  212°  F.  338°  F. 

McMichael     0.50  0.55  0.60  0.65 

Sayboldt    "A"    0.50  1.00 

Sayboldt    "C"     —  0.46  0.72 

Engler      0.035  0.030  0.028  0.027 

Tagliabue     0.25  0.28  0.51 

Penn.   R.    R.    Pipett 0.30  0.47  0.51  0.94 

Scott    ', 0.13  0.13 

Redwood    0.83  0.85  0.88  0.90 

Magruder    Plunger    ___  1.25  1.04  2.00 

Ostwald    1.90  1.85  1.68  1.30 

To  proceed  now,  if  the  Sayboldt  viscosity  of  an  oil  at  100°  F. 
is  100  sec.,  the  Redwood  viscosity  is  found  by  multiplying  this  by  0.85, 
thereby  giving  85  as  the  Redwood  viscosity  at  100°  F.  similarly,  the 
Kngler  number  is  found  by  multiplying  the  Sayboldt  viscosity  by  0.03,  giv- 
ing 3.0  as  the  Engler  number  at  100°  F.  These  conversion  factors 
are  not  exact,  as  they  vary  greatly  with  the  actual  viscosities,  and  are 
merely  given  here  to  demonstrate  the  existing  differences  in  actual  re- 
sults. 

CRITICAL  TEMPERATURES 

When  a  liquid  and  its  vapor  confined  in  a  vessel  are  heated, 
a  portion  of  the  liquid  vaporizes,  the  pressure  increases,  the  density  of 
the  vapor  increases,  and  the  density  of  the  liquid  decreases.  When  a 
certain  temperature  is  reached,  the  -density  of  the  liquid  and  of  the  vapor 
become  identical,  and  the  vapor1  and  the  liquid  are  physically  identical. 
This  temperature  is  called  "critical  temperature"  of  the  liquid. 


LIQUID  SUBSTANCES  81 

The  heat  of  vaporization  of  a  liquid  is  less,  the  higher  the  tem- 
perature (and  pressure)  at  which  the  vaporisation  takes  place,  and 
becomes  zero  at  'the  critical  temperature.  For  example: 

The  heat  of  vaporization  of  water  is  606.5  at  0  degree,  539.9  at 
100  degree,  and  464.3  at  200  degree. 

In  the  following  tables  the  critical  temperatures  of  certain  sub- 
stances are  given: 


CRITICAL     TEMPERATURES     OF    VARIOUS     LIQUIDS 

Deg.  C.  Deg.  C. 

Alcohol     (ethyl)    240      Methane     (CH*)    81 

Ammonia    (NH3)     130       Nitrogen     146 

Benzol  280      Nitrous    oxide    (N-'O) 35.4 

Bromine    302      Oxygen    118 

Carbon   monoxide    (CO) 141  Sulphuretted    hydrogen     (IPS)   100 

Carbon    dioxide    (CO-') 31      Sulphur    dioxide     (SQ2) 156 

Chlorine  141      Turpentine    oil 376 

Chloroform    260      Water    365 

HEATING     FUEL    OIL 

Fuel  oil  is  generally  preheated  in  order  to  reduce  the  viscosity  and 
therefore  to  assist  the  atomization  of  the  oil  in  oil  injection  devices. 
There  is  no  practical  gain  in  heating  the  oil  above  the  temperature  cor- 
responding to  a  viscosity  for  which  the  atomizers  produce  efficient  ato- 
mization. This  viscosity  usually  is  8  Engler.  In  the  case  of  the  more 
viscous  oils,  care  should  be  taken  that  the  oil  is  not  heated  above  the 
flashpoint.  Unless  leaks  in  the  oil  lines  are  guarded  against?  excessive 
preheating  to  reduce  the  viscosity  would  be  dangerous  expedient.  A 
temperature  of  300°  F.  is  frequently  sufficient  for  fine  atomization  of  the 
heaviest  oils  and  for  their  complete  and  perfect  combustion  in  the  engine. 

For  proper  atomization,  the  oil  should  be  preheated  to  the  tem- 
perature given  in  following  table: 

PREHEATING  TEMPERATURE  FOR  FUEL  OIL 

Degree  Baume         Specific  Gravity  60°/60°  p.*       Temp.  Degr.  F. 
12.0  0.9859  300 

16.0  0.9589  250 

20.0  0.9333  200 

Note:     *  Indicates  that  the  specific  gravity  of  the  oil  at  60°  Fahrenheit 
is  referred  to  water  at  60°  Fahrenheit  as  unity. 


LIQUID  SUBSTANCES 


DENSITY   AND   VISCOSITY    OF   WATER    AT    DIFFERENT   TEMPERA- 
TURES 

Experiments  by  Stanton  on  the  flow  of,  air  through  pipes  of  5  and 
7.4  centimeters  diameter  show  that  for  exact  similarity  of  distribution  of 
velocity  over  the  cross-section  of  the  pipe  the  center  velocities  should 
be  inversely  proportional  to  the  pipe  diameters,  that  is,  that  the  ratio 
of  average  velocity  to  center  velocity  will  be  the  same  in  two  pipes 
of  different  diameters  if  this  condition  be  satisfied.  A  comparison  by 
E.  Buckingham  of  the  experiments  by  Stanton  and  by  Saph  and  Schroder 
on  flow  through  brass  tubes  indicates  that  to  secure  similar  flow  condi- 
tions with  fluids  of  different  densities  and  viscosities  the  velocities  and 
diameters  should  be  so  selected  as  to  satisfy  the  equation: 


V  a  d 


=  a  constant 


in  which  V  is  the  central  velocity,  a  radius  of  the  pipe,  d  the  density 
of  the  fluid,  and  m  the  coefficient  of  viscosity.  The  density  and  viscosity 
of  water  at  different  temperatures  are  given  in  the  following  table: 


Temp. 

32 

40 

50 

60 

70 

80 

90 
100 
110 
120 


Coefficient 

Wt.  per 

Viscosity 

Cu.  Ft. 

Dynes  per 

Temp. 

Lb. 

Sq.  Cm. 

62.42 

.0179 

130 

62.42 

.0155 

140 

62.41 

.0131 

150 

62.37 

.0112 

160 

62.31 

.0097 

170 

62.23 

.0086 

180 

£2.13 

.0077 

190 

62.02 

.0068 

200 

61.89 

.0062 

210 

61.74 

.0056 

Coefficient 

Wt.  per 

Viscosity 

Cu.  Ft. 

Dynes  per 

Lb. 

Sq.  Cm. 

61.56 

.0051 

61.37 

.0047 

61.18 

.0043 

60.98 

.0040 

60.77 

.0037 

60.55 

.0035 

60.32 

.0032 

60.07 

.0030 

59.82 

.0028 

UNIT  OF  HEAT 

The  quantity  measure  of  heat  is  the  thermal  unit.  The  British 
thermal  unit  (as  distinguished  from  the  French  thermal  unit,  or  calorie) 
is  that  quantity  of  heat  which  is  required  to  raise  the  temperature 
of  one  pound  of  pure  water  through  one  degree  Fahrenheit,  at  or  near 
39.1°  Fahrenheit,  the  temperature  of  maximum  density  of  water.  As 
employed  in  general  practice,  the  term  is  usually  abbreviated  to 
"B.  T.  U." 

The  relation  existing  between  the  temperature  of  water  in  degrees 
Fahrenheit  and  the  number  of  thermal  units  contained  therein,  together 
with  the  increase  in  the  number  of  thermal  units  for  each  increment 
of  temperature  of  5  degrees,  is  indicated  in  following  table. 


LIQUID  SUBSTANCES 


83 


NUMBER    OF    THERMAL    UNITS    CONTAINED    IN    ONE    POUND    OF 

WATER 


Temp. 

No  of 

Temp. 

No  of 

Degrees 

Thermal 

Increase 

Degrees 

Thermal 

Increase 

P. 

Units 

P. 

Units 

as 

35.000 



215 

215.939 

5.065 

40 

40.001 

5.001 

220 

221.007 

5.068 

45 

45.002 

5.001 

225 

226.078 

5.071 

50 

60.003 

5.001 

230 

231.153 

5.075 

55 

55.006 

5.003 

235 

236.232 

5.079 

60 

60.009 

5.003 

240 

241.313 

5.081 

65 

65.014 

5.005 

245 

246.398 

5.085 

70 

70.020 

5.006 

250 

251.487 

5.089 

75 

75.027 

5.007 

255 

256.579 

5.092 

80 

80.036 

5.009 

260 

261.674 

5.095 

85 

85.045 

5.009 

265 

266.774 

5.100 

90 

<'90.055 

5.010 

270 

271.878 

5.104 

95 

95.067 

5.012 

275 

276.985 

5.107 

100   . 

100.080 

5.013 

280 

282.095 

5.110 

105 

105.095 

5.015 

285 

287.210 

5.115 

110 

110.110 

5.015 

290 

292.329 

5.119 

115 

115.129 

5.019 

295 

297.452 

5.123 

120 

120.149 

5.020 

300 

302.580 

5.128 

125 

125.169 

5.020 

305 

307.712 

5.132 

130 

130.192 

5.023 

310 

312.848 

5.136 

135 

135.217 

5.025 

315 

317.988 

5.140 

140 

140.245 

5.028 

320 

323.134 

5.146 

145 

145.175 

5.030 

325 

328.284 

5.150 

150 

0.50.305 

5.030 

330 

333.438 

5.154 

155 

155.339 

5.034 

335 

338.596 

5.158 

160 

160.374 

5.035 

340 

343.750 

5.163 

165 

165.413 

5.039 

345 

348.927 

5.168 

170 

170.453 

5.040 

350 

354.101 

5.174 

175 

175.497 

5.044 

355 

359.280 

5.179 

180 

180.542 

5.045 

360 

364.464 

5.184 

185 

185.591 

5.049 

365 

369.653 

5.189 

190 

190.643 

5.052 

370 

374.846 

5.193 

195 

195.697 

5.054 

375 

380.044 

5.198 

200 

200.753 

5.056 

380 

385.247 

5.203 

205 

205.813 

5.060 

385 

390.456 

5.209 

210 

210.874 

5.061 

390 

395.672 

5.216 

ANALYSIS  OF  SEA  WATER 

Salt  water  is  known  to  be  a  solvent  of  iron  or  steel,  and  when 
brought  to  a  stage  of  high  heating  temperature  in  the  exhaust  of  Inter- 
nal Combustion  Engines,  the  magnesium  chloride,  about  250  grains  of 
which  are  contained  in  every  gallon,  becomes  highly  corrosive, 


84  LIQUID  SUBSTANCES 

TABLE   OF  SOLVING   SUBSTANCES 

Carbonate   of    lime 9.79  grains  per  gal. 

Sulphate    of    lime 114.36  grains  per  gal. 

Sulphate   of  magnesium 134.86  grains  per  gal. 

Chloride    of    magnesium 244.46  grains  per  gal. 

Chloride   of    sodium 1706.00  grains  per  gal. 


Total    solids 2209.47  grains  per  gal. 


OFFICIAL   TEMPERATURES   AND   CRITICAL    PRESSURES 

Critical  Temperature  Critical 

-  Pressures  in 

Substances                                                             °C                °F  Atmospheres 

Alcohol     235                 455  64 

Ammonia   (NH.^)    130                 266  115 

Corbon    dioxide    (COJ    31                   88  73 

Carbon  disulphide   CCS.,) 273                523  *      73 

Ether    I 195                 383  36 

Hydrogen     — 235            —391  20 

Nitrogen    —146            —231  33 

Oxygen     —118             —180  50 

Sulphur  dioxide    (SO.,)    155                311  79 

Water     365                689  200 


HYDROMETER    SCALES 

Barkometer    Degrees  =   the   first   three    figures   of   the    decimal    of   the 
corresponding  sipecific  gravity,  thus: 

1.008  specific  gravity  =  8  degrees  Barkometer. 
1.015         "  "        =     15 

1.223         "  "         =  223 

Twaddell   Degrees  =  the  first  three  figures  of  the  decimal  of  the  corre- 
sponding specific  gravity,  divided  by  five,  thus: 

1.010  specific  gravity  —    2  degrees  Twaddell. 
1.125         "  "       =  25 

Densimetric  Degrees  =  the  first  two  figures  of  the  decimal  of  the  cor- 
responding specific  gravity,  thus: 

1.018  specific  gravity  =  1.8  degrees  Densimetric. 
1.234         "  "         =  23.4 

Brix   Degrees  =  sugar  percentages  =  1.8°   Baume   (about). 


LIQUID  SUBSTANCES 


85 


SPECIFIC    HEAT   OF   WATER 


Specific    Heat    at 
Temperature  Given    Temp. 

Degrees  F.  Freezing  Point 

=  1  degree. 

32    1.0000 

50    .    1.0005 

68    1.0012 

86    1.0020 

104    1.0030 

122    1.0042 

140    1.0056 

158    .    1.0072 

176    1.0089 

194    _—    1.0109 

212    .  1.0130 

230    .  1.0153 


Specific    Heat    at 
Temperature  Given    Temp. 

Degrees  F.  Freezing  Point 

=  1  -degree. 

248    1.0177 

266 1.0204 

284    1.0252 

302    1.0262 

320    1.0294 

338    1.0328 

356 1.0364 

374    .  1.0401 

394    1.0440 

410    .        1.0481 

428    .  1.0524 

446    .  1.0'568 


(a) 


(c) 


"Tyco"  Instruments — (a)  Draft  Gauge,     (&)  High  Pressure  Thermometer. 
(c)  Vacuum  Gauge,     (d)  Low  Pressure  Thermo  Gauge. 


86  LIQUID  SUBSTANCES 

HOW  A  THERMOMETER    IS  GRADUATED 

A  mercurial  tube  is  placed  in  melting  ice,  which  is  'the  temperature 
at  which  water  freezes  or  ice  melts.  Wheii  the  mercury  has  fallen  to 
its  lowest  point  it  is  marked  on  the  tube.  Then  it  is  placed  in  'boiling 
water  under  atmospheric  pressure  at  sea  level.  When  the  mercurial 
column  reaches  a  certain  height  it  remains  there  until  taken  out,  this 
point  is  marked.  Now  we  have  the  freezing  and  boiling  points  and  we 
can  graduate  the  thermometer  either  Centigrade  (English  Thermometer) 
or  Fahrenheit. 

If  we  graduate  it  Fahrenheit,  we  will  let  the  freeging  point  equal  32° 
and  the  boiling  ipoint  212°,  then  we  have  212  —  32  =  180°  between  freez- 
ing and  boiling;  then  the  space  between  212  degrees  and  32  degrees  will 
be  equally  divided  into  180  parts,  each  part  representing  a  degree.  On 
the  Centigrade,  we  will  let  0  -equal  the  freezing  point  and  100°  the  boiling 
point,  then  there  is  100  degrees  between  the  freezing  and  boiling  point 
on  the  Centigrade;  then  1  degree  of  Fahrenheit  is  equal  to  100  -r- 180,  or 
5/9°  Centigrade. 

Fahrenheit  and  Centigrade  Thermometers 

Everyone  is  familiar  with  the  Fahrenheit  Thermometer  and  its  read- 
ings, but  comparatively  few  are  familiar  with  the  significance  of  the 
Centigrade  Scale.  At  the  present  time  many  of  the  heating  instruments 
are  graduated  to  the  Centigrade  readings.  To  convert  the  readings  from 
one  scale  to  the  other,  use  'the  following  rule: 

Subtract  32  from  the  Fahrenheit,  divide  the  remainder  by  9  and 
multiply  by  5. 

Example: 

—  Convert  212°  Fahrenheit  to  Centigrade  equivalent. 
Solution: 

212—32  =  180 
180 -r-    9=    20 

20  X    5  =  100°  C.,  or  the  respective  readings  of  the  temparature 
at  which  water  boils. 

To  convert  Centigrade  to  Fahrenheit  readings,  divide  the  Centigrade 
readings  by  5,  multiply  by  9  and  add  32. 

Example: 

Convert  100°  C.  to  Fahrenheit  equivalent. 
Solution: 

100  -r-    5=    20 
20  X    9  =  180 
180  +  32  =  212°  F. 


LIQUID  SUBSTANCES 


87 


SPECIFIC  GRAVITIES  IN  DEGREES  BEAUME: 
LIQUIDS   LIGHTER  THAN  WATER 


Degree 
Baume 

10  ._ 

11  __ 

12  — 

13  _ 


Specific-, 
Gravity 

1.000 

0.993 

0.986 

0.979 


14 0.972 

15  0.966 

16 0.959 

17 0.952 

18 0.946 

19  , 0.940 

20 0.933 

21  0.927 

22 0.921 

23 0.915 

24  _         _    0.909 


Degree  Specific 

Baume  Gravity 

25 0.903 

26 0.897 

27 0.892 

28 0.886 

29 0.881 

30 0.875 

31 0.870 

32 0.864 

33 0.859 

34 0.854 

35 0.849 

36 0.843 

37 0.838 

38 0.833 

39  _         _  0.828 


Degree 
Baume 

40  _ 

41  _. 

42  _ 

43  _ 


Specific 
Gravity 
.  0.824 
0.819 
.  0.814 
.   0.805 


46 0.796 

48 0.787 

50  , 0.778 

52 0.769 

54 0.761 

56 0.753 

58 0.745 

60 0.737 

65 0.718 

70 0.700 

75  _         _  0.683 


THE  BEAUME  SCALE: 

The  usual  method  of  indicating  the  weight  of  crude  oil  for  fuel  ia 
by  the  Beaume  Scale.  The  numbers  of  this  scale  are  given  by  the 
formula : 

140 

Degree  Beaume  =  -         —130;  where  S.  G.  is  the  specific  gravity,  water 
S.<G.      being  —  1. 

In  the  following  table  the  specific  gravity  and  weight  iper  gallon  for 
the  different  degrees  on  the  Beaume  scale  are  given: 


Degrees 

Pounds  per 

Specific 

Beaume 

UjS.  Gallon 

Gravity 

10 

8.336 

1.000 

11 

8.277 

.993 

12 

8.219 

.986 

13 

8.161 

.979 

14 

8.102 

.972 

15 

8.052 

.966 

16 

7.994 

.959 

17 

7.935 

.952 

18 

7.885 

.946 

19 

7.835 

.940 

20 

7.777 

.933 

21 

7.727 

.927 

22 

7.677 

.921 

23 

7.627 

.915 

24 

7.577 

.909 

25 

7.527 

.903 

Degrees 

Pounds  per 

Specific 

Beaume 

U,S.  Gallon 

Gravity 

26 

7.477 

.897 

27 

7.435 

.892 

28 

7.385 

.886 

29 

7.344 

.881 

30 

7.294 

.875 

31 

7.252 

.870 

32 

7.202 

.864 

33 

7.160 

.859 

34 

7.119 

.854 

35 

7.069 

.848 

36 

7.027 

.843 

37 

6.985 

.838 

38 

6.944 

.833 

39 

6.902 

.828 

40 

6.869 

.824 

88  LIQUID  SUBSTANCES 

SPECIFIC    GRAVITIES    IN    DEGREES    BAUME    AND   TWADDLE. 
LIQUIDS    HEAVIER   THAN    WATER. 


Hydrometer  Reading 
—  Degrees  

Specific 
Gravity 

Hydrometer 

"Pl^vrv-M 

Reading 
ees  

Specific 
Gravity 

uegr 

Twaddle 

Baume 

Twaddle 

Baume 

0 

.0 

1.000 

40 

24.0 

1.200 

1 

.     .7 

1.005 

41 

24.5 

1.205 

2 

1.4 

1.010 

42 

25.0 

1.210 

3 

2.1 

1.015 

43 

25.5 

1.215 

4 

2.7 

1.020 

44 

26.0 

1.220 

5 

3.4 

1.025 

45 

26.4 

1.225 

6 

4.1 

1.030 

46 

26.9 

1.230 

7 

4.7 

1.035 

47 

27.4 

1.235 

8 

5.4 

1.040 

48 

27.9 

1.240 

9 

6.0 

1.045 

49 

28.4 

1.245 

10 

6.7 

1.050 

50 

28.8 

1.250 

11 

7.4 

1.055 

51 

29.3 

1.255 

12 

8.0 

1.060 

52 

29.7 

1.260 

13 

8.7 

1.065 

53 

30.2 

1.265 

14 

9.4 

1.070 

54 

30.6 

1.270 

15 

10.0 

1.075 

55 

31.1 

1.275 

16 

10.6 

1.080 

56 

31.5 

1.280 

17 

11.2 

1.085 

57 

32.0 

1.285 

18 

11.9 

1.090 

58 

32.4 

1.290 

19 

12.4 

1.095 

59 

32.8 

1.295 

20 

13.0 

1.100 

60 

33.3 

1.300 

21 

13.6 

1.105 

61 

33.7 

1.305 

22 

14.2 

1.110 

62 

34.2 

1.310 

23 

14.9 

1.115 

63 

34.6 

1.315 

24 

15.4 

1.120 

64 

35.0 

1.320 

25 

16.0 

1.125 

65 

35.4 

1.325 

26 

16.5 

1.130 

66 

35.8 

1.330 

27 

17.1 

1.135 

67 

36.2 

1.335 

28 

17.7 

1.140 

68 

36.6 

1.340 

29 

18.3 

1.145 

69 

37.0 

1.345 

30 

18.8 

1.150 

70 

37.4 

1.350 

31 

19.3 

1.155 

71 

37.8 

1.355 

32 

19.8 

1.160 

72 

38.2 

.360 

33 

20.3 

1.165 

73 

38.6 

.365 

34 

20.9 

1.170 

74 

39.0 

1.370 

35 

21.4 

1.175 

75 

39.4 

.375 

36 

22.0 

1.180 

76 

39.8 

.380 

37 

22.5 

1.185 

77 

40.1 

1.385 

38 

23.0 

1.190 

78 

40.5 

1.390 

39 

23.5 

1.195 

79 

40.8 

1.395 

LIQUID  SUBSTANCES 

SPECIFIC    GRAVITIES    IN    DEGREES    BAUME   AND   TWADDLE. 
LIQUIDS   HEAVIER   THAN    WATER. 


89 


Hydromete 

Dpcrr 

r  Reading 
ces  

Specific 
Gravity 

Hydrometer  Reading 
—  Degrees  

Specific 
Gravity 

Twaddle 

Baume 

Twaddle 

Baume 

80 

41.2 

1.400 

120 

54.1 

1.600 

81 

41.(> 

1.405 

121 

54.4 

1.605 

82 

42.0 

1.410 

122 

54.7 

1.610 

83 

42.3 

1.415 

123 

55.0 

1.615 

84 

42.7 

1.420 

124 

55.2 

1.620 

85 

43.1 

1.425 

125 

55.5 

1.625 

86 

43.4 

1.430 

126 

558 

1.630 

87 

43.8 

1.435 

127 

56.0 

1.635 

88 

44.1 

1.440 

128 

56.3 

1.640 

89 

44.4 

1.445 

129 

56.6 

1.645 

90 

448 

1.450 

130 

56.9 

1.650 

91 

45.1 

1.455 

131 

57.1 

1.655 

92 

45.4 

1.460 

132 

57.4 

1.660 

93 

45.8 

.   1.465 

133 

57.7 

1.665 

94 

46.1 

1.470 

134 

57.9 

1.670 

95 

46.4 

1.475" 

135 

58.2 

1.675 

96 

46.7 

1.480 

136 

58.4 

1.680 

97- 

47.1 

1.485 

137 

58.7 

1.685 

98 

47.4 

1.490 

138 

58.9 

1.690 

99 

47.8 

1.495 

139 

59.2 

1.695 

100 

48.1 

1.500 

140 

59.5 

1.700 

101 

48.4 

1.505 

141 

59.7 

1.705 

102 

48.7 

1.510 

142 

60.0 

1.710 

103 

49.0 

1.515 

143 

60.2 

1.715 

104 

49.4 

•  1.520 

144 

60.4 

1.720 

105 

49.7 

1.525 

145 

60.6 

1.725 

106 

50.0 

1.530 

146 

60.9 

1.730 

107 

50.3 

1.535 

147 

61.1 

1.735 

108 

50.6 

1.540 

148 

61.4 

1.740 

109 

50.9 

1.545 

149 

61.6 

1.745 

110 

51.2 

1.550 

150 

61.8 

1.750 

111 

51.5 

1.555 

151 

62.1 

1.755 

112 

51.8 

1.560 

152 

62.3 

1.760 

113 

52.1 

1.565 

153 

62.5 

1.765 

114 

52.4 

1.570 

154 

62.8 

1.770 

115 

52.7 

1.575 

155 

63.0 

1.775 

116 

53.0 

1.580 

156 

63.2 

1.780 

117 

53.3 

1.585 

157 

63.5 

1.78& 

118 

53  6 

1.590 

158 

63.7 

1.790 

119 

53.9 

1.595 

159 

64.0 

1.795 

90  LIQUID  SUBSTANCES 

SPECIFIC    GRAVITIES    IN    DEGREES    BAUME   AND    TWADDLE. 
LIQUIDS   HEAVIER   THAN    WATER. 


Hydrometer  Reading 

Specific 

Hydrometer  Reading 

Specific 

—Degrees  

Gravity 

—  Degrees  

Gravity 

Twaddle 

Baume 

Twaddle 

Baume 

160 

64.2 

1.800 

165 

65.2 

1.825 

161 

64.4 

1.805 

166 

65.5 

1.830 

162 

64.6 

1.810 

167 

65.7 

1.835 

163 

64.8 

1.815 

168 

65.9 

1.840 

164 

65.0 

1.820 

169 

66.1 

1.845 

170 

66.3 

1.850 

171 

66.5 

1.855 

TABLE  OF  EQUIVALENT  FOR  FUEL  OIL 

This  chart  shows  the  equivalents  for  fuel  oils  at  various  gravities 
and  is  taken  at  60°  Fahrenheit.  Naturally,  a  temperature  adjustment 
must  be  made  to  determine  true  specific  gravity.  This  adjustment  is 
as  follows: 

For  every  degree  above  60°  F.,  subtract  .0004 
For  every  degree  below  60°  F.,  add          .0004 


Lbs.  per 

Lbs  pei- 

Cu.  Ft. 

Gal. 

Gal. 

Bbls. 

Specific 

Beaume 

Amer. 

English 

Amer. 

Amer. 

English 

Amer. 

Gravity 

Gravity 

Gal. 

Gal. 

per  Ton 

per  Ton 

per  Ton 

per  Ton 

1.0000 

10. 

8.331 

10. 

35.94 

268.875 

224. 

6.40 

.9956 

10.6 

8.302 

9.995 

36.09 

269.81 

224.75 

6.42 

.9930 

11. 

8.273 

9.930 

36.19 

270.76 

225.55 

6.44 

.9895 

11.5 

8.244 

9.895 

36.32 

271.71 

226.33 

6.46 

.9860 

12. 

8.214 

9.860 

36.45 

272.67 

227.13 

6.49 

.9825 

12.5 

8.185 

9.825 

35.57 

273.66 

227.96 

6.51 

.9790 

13. 

8.156 

9.790 

36.71 

274.62 

228.80 

6.54 

.9755 

13.5 

8.127 

9.705 

36.84 

275.62 

229.62 

6.56 

.9720 

14. 

8.098 

9.702 

36.97 

276.67 

230.49 

6.58 

.9685 

14.5 

8.069 

9.685 

37.10 

277.47 

231.16 

6.60 

.9655 

15. 

8.044 

9.650 

37.22 

278.46 

231.98 

6.63 

.9625 

15.5 

8.019 

9.625 

37.34 

279.33 

232.71 

6.65 

.9695 

16. 

7.994 

9.595 

37.46 

280.19 

233.42 

6.66 

.9560 

16.5 

7.964 

9.560 

37.59 

281.26 

234.31 

6.69 

.9530 

17. 

7.929 

9.530 

37.71 

282.22 

235.11 

6.74 

.9495 

17.5 

7.910 

9.495 

37.85 

283.08 

235.90 

6.75 

.9465 

18. 

7.885 

9.465 

37.97 

284.08 

236.66 

6.76 

.9430 

18.5 

7.856 

9.430 

38.11 

285.13 

257.52 

6.76 

.9400 

19. 

7.831 

9.400 

38.23 

286.04 

238.30 

6.81 

.9370 

19.5 

7.806 

9.370 

38.35 

286.95 

239.06 

6.83 

.9340 

20. 

7.781 

9.340 

38.47 

287.88 

239.82 

6.85 

,9310 

20.5 

7.756 

9.310 

38.60 

288.88 

240.60 

6.87 

LIQUID  SUBSTANCES 


TABLE    EQUIVALENT    FOR    FUEL    OIL 


1)1 


Lbs.  per 

Lbs  pei- 

Cu.  Ft. 

Gal. 

Gal. 

Bbls. 

Specific 

Beaume 

Amer. 

English 

Amer. 

Amer. 

English 

Amer. 

Gravity 

Gravity 

Gal. 

Gal. 

per  Ton 

per  Ton 

per  Ton 

per  Ton 

.9280 

21. 

7.730 

9.280 

38.73 

289.74 

241.34 

6.89 

.9250 

21.5 

7.706 

9.250 

38.85 

290.68 

242.16 

6.89 

.9220 

22. 

7.680 

9.220 

38.98 

291.62 

242.95 

6.94 

.9195 

22.5 

7.660 

9.195 

39.09 

292.42 

243.61 

6.96 

.9165 

23. 

7.635 

9.165 

39.21 

293.25 

244.40 

6.98 

.9135 

23.5 

7.615 

9.135 

39.34 

294.15 

245.21 

7.00 

.9105 

24. 

7.585 

9.105 

39.47 

295.31 

246.01 

7.03 

.9045 

25. 

7.536 

.  9.040 

39.73 

297.24 

247.64 

7.07 

.8990 

26. 

7.490 

8.990 

39.97 

299.06 

249.15 

7.08 

.8930 

27. 

7.440 

8.930 

40.24 

301.07 

250.84 

7.12 

.8870 

28. 

7.390 

8.870 

40.51 

303.11 

252.53 

7.21 

.8815 

29. 

7.344 

8.815 

40.77 

305.01 

254.00 

7.26 

.8755 

30. 

7.294 

8.755 

41.04 

307.10 

255.85 

7.31 

.8700 

31. 

7.248 

8.700 

41.31 

309.19 

257.47 

7.36 

.8650 

32. 

7.206 

8.650 

41.54 

310.85 

258.94 

7.40 

.8595 

33. 

7.160 

8.595 

41.81 

312.84 

260.61 

7.44 

.8545 

34. 

7.119 

8.545 

42.05 

314.65 

262.14 

7.46 

.8490 

35. 

7.070 

8.490 

42.32 

316.83 

263.83 

7.54 

.8440 

36. 

7.031 

8.440 

42.58 

318.58 

265.40 

7.58 

.8395 

37. 

6.994 

8.395 

42.81 

320.27 

266.82 

7.62 

.8345 

38. 

6.952 

8.345 

43.06 

322.67 

268.42 

7.70 

.8295 

39. 

6.911 

8.295 

43.32 

324.12 

270.04 

7.71 

.8250 

40. 

6.873 

8.250 

43.56 

325.90 

271.51 

7.78 

RELATIVE  COST  OF  COAL  AND  OIL 

The  primary  object  in  giving  this  table  is  -to  draw  an  approximate 
comparison  in  cost  of  coal  as  used  in  generation  of  steam  in  contrast  to 
oil  used  in  Diesel  Engines  for  fuels.  It  is  understood,  that  the  variation 
of  either  coal,  as  well  as  oil,  in  prices,  average  about  from  12  to  14%. 
The  following  tables  will  give  the  average  prevailing  fuel  cost  of  either 
coal  or  oil. 


Oil 

Oil 

Coal 

Oil 

Oil 

Coal 

cents  per 

dollars  per 

dollars  per 

cents  per 

dollars  per 

dollars  per 

gallon 

barrel 

ton 

gallon 

barrel 

ton 

2.00 

$0.82 

$3.92 

3.25 

$1.33 

$6.37 

2.25 

0.92 

4.41 

3.50 

1.43 

6.86 

2.50 

1.02 

4.90 

4.00 

1.64 

7.84 

2.75 

1.13 

5.39 

4.50 

1.84 

8.82 

3.00 

1.23 

5.88 

5.00 

2.05 

9.80 

92 


LIQUID  SUBSTANCES 


CONVERSION    TABLE    FOR    DEGREES    BAUME    (LIGHTER    THAN 
WATER)   TO  SPECIFIC  GRAVITY  AND  LBS.  PER  GALLON 


Degrees 

Specific 

Pounds  in 

Degrees 

Specific 

Pounds  in 

Baume 

Gravity 

1  Gallon 

Baume 

Gravity 

1  Gallon 

(American) 

(American) 

10 

1.0000 

8.33 

43 

.8092 

6.74 

11 

.9929 

8.27 

44 

.8045 

6.70 

12 

.9859 

8.21 

45 

.8000 

6.66 

13 

.9790 

8.16 

46 

.7954 

6.63 

14 

.9722 

8.10 

47 

.7909 

6.59 

15 

.9655 

8.04 

48 

.7865 

6.55 

16 

.9589 

7.99 

49 

.7831 

6.52 

17 

.9523 

7.93 

50 

.7777 

6.48 

18 

.9459 

7.88 

51 

.7734 

6.44 

19 

.9395 

7.83 

52 

.7692 

6.41 

20 

.9333 

7.78 

53 

.7650 

6.37 

21 

.9271 

7.72 

54 

.7608 

6.34 

22 

.9210 

7.67 

55 

.7567 

6.30 

23 

.9150 

7.62 

56 

.7526 

6.27 

24 

.9090 

7.57 

57 

.7486 

6.24 

25 

.9032 

7.53 

58 

.7446 

6.20 

26 

.8974 

7.48 

59 

.7407 

6.17 

27 

.8917 

7.43 

60 

.7368 

6.14 

28 

.8860 

7.38 

61 

.7329 

6.11 

29 

.8805 

7.34 

62 

.7290 

6.07 

30 

.8750 

7.29 

63 

.7253 

6.04 

31 

.8695 

7.24 

64 

.7216 

6.01 

32 

.8641 

7.20 

65 

.7179 

5.98 

33 

.8588 

7.15 

66 

.7142 

5.95 

34 

.8536 

7.11 

67 

.7106 

5.92 

35 

.8484 

7.07 

68 

.7070 

5.89 

36 

.8433 

7.03 

69 

.7035 

5.86 

37 

.8383 

6.98 

70   s 

.7000 

5.83 

38 

.8333 

6.94 

75 

.6829 

5.69 

39 

.8284 

6.90 

80 

.6666 

5.55 

40 

.8235 

6.86 

85 

.6511 

5.42 

41 

.8187 

6.82 

90 

.6363 

5.30 

42 

.8139 

6.78 

95 

.6222 

5.18 

United  States 
New  York  __. 
Imperial  __. 


TABLE   OF   GALLONS 

Cubic  In. 

in  a 

Gallon 

231 

231.819 

277.274 


Weight  of  a 
Gal.  in  Ibs. 
Avoirdupois 
8.33 
8.00 
10.00 


Gallons  in 
a  Cubic 
Foot 
7.480 
7.901 
6.232 


LIQUID  SUBSTANCES 


93 


CONVENIENT    TABLE    TO    ESTABLISH     POUNDS  PER    SQUARE 
INCHES  TO  HEAD  IN  FEET 

For  Liquids  at  62°  Fahrenheit,  Weighing  62.364  Ib.  Per  Qu-  Ft. 

84 194.0 

85  196.3 

86  198.6 

87  200.9 

88  203.2 

89  205.5 

90  207.8 

91  210.2 

92 212.5 

93  214.8 

94 217.1 

95  219.4 

96 221.7 

97 224.0 

98  226.3 

99  228.6 

100  230.9 

105 242.4 

110 254.0 

115  265.5 

120  277.1 

125 288.6 

130  300.2 

135 311.7 

140  323.3 

145  334.8 

150 346.4 

155 357.9 

160  ._  369.5 

165  381.0 

170  392.6 

175  ___ 404.1 

190  438.8 

195  450.3 

200  461.9  - 

210  485.0 

220  508.1 

230 531.2 

240 554.3 

250 577.4 

260  __. 600.5 

270 623.6 

280 646.6 

290  _     _  669.7 


Pounds 

Head 

Pounds 

Head 

per 

in 

per 

in 

Sq.  In. 

Feet 

Sq.  In. 

Feet 

2 

4.619 

43 

99.31 

3 

6928 

44 

101.6 

4 

__   9.238 

45  ___  _ 

103.9 

5   _  _ 

__  11.55 

46 

106.2 

6 

13.86 

47 

108.5 

7 

16  17 

48 

110.8 

8 

18.48 

49 

113.2 

9  

20.78 

50 

115.5 

10 

_   23.09 

51 

117.8 

11 

25.40 

52   .. 

120.1 

12 

27.71 

53 

122.4 

13 

30.02 

54 

124.7 

14 

32.33 

55 

127.0 

15 

34.64 

56  

129.3 

16  _  __ 

36.95 

57 

131.6 

17  

__  39.26 

58 

133.9 

18   

41.57 

59 

136.3 

19 

43.88 

60 

138.6 

20 

46.19 

61 

140.9 

21 

48.50 

62   

143.2 

22 

50.81 

63  

145.5 

23  

53.12 

64  

147.8 

24   _  _ 

55.43 

65  

150.1 

25  

57.74 

66  ___ 

152.4 

26   _  _ 

._   60.05 

67 

154.7 

27   _  _ 

...  62.36 

68 

157.0 

28  

64.66 

69  _ 

159.3 

29   _  _ 

66.97 

70 

161.7 

30   ___ 

69.28 

71 

163.0 

31 

71.59 

72  

166.3 

32   _  _ 

73.90 

73  __   __ 

168.6 

33   _  _ 

76.21 

74  _ 

170.9 

34 

78  52 

75 

173.2 

35 

80.83 

175.5 

36 

83.14 

77 

177.8 

37 

85.45 

78 

180.1 

38  

.  .  87.76 

79 

182.4 

39 

90.07 

80 

184.8 

40   _  . 

92.38 

81 

187.1 

41 

94.69 

82 

189.4 

42 

97.00 

83 

191.7 

94 


LIQUID  SUBSTANCES 


Pounds 

Head 

Pounds 

Head 

Pounds 

Head 

per 

in 

per 

in 

per 

in 

Sq.  In. 

Feet 

Sq.  In. 

Feet 

Sq.  In. 

Feet 

300 

692.8 

370 

854.5 

440 

1016. 

310 

715.9 

380 

877.6 

450 

1039 

320 

739.0 

390 

900.7 

460 

1062 

330 

762  1 

400 

923.8 

470 

1085 

340 

785.2 

410 

946.9 

480 

1108. 

350 

808.3 

420 

970.0 

490 

1132. 

360 

831.4 

430 

993.1 

500 

1155. 

UNITED 

STATES   GALLONS    IN    ROUND   TANKS 

FOR    ONE    FOOT 

IN    DEPTH 

Diam  of 

No. 

Cub.  Ft. 

Diam  of 

No. 

Cub.  Ft. 

Tanks 

U.  S. 

and  area 

Tanks 

U.  S. 

and  area 

Ft.  In. 

Gals. 

in  sq.  ft. 

Ft.  In. 

Gals. 

in  sq.  ft. 

1       0 

5.87 

.785 

3       5 

68.58 

9.168 

1       1 

6.89 

.922 

3       6 

71.97 

9.621 

1       2 

8.00 

1.069 

3       7 

75.44 

10.085 

1       3 

9.18 

1.227 

3       8 

78.99 

10.559 

1       4 

10.44 

1.396 

3       9 

82.62 

11.045 

1       5 

11.79 

1.576 

3     10 

86.33 

11.541 

1       6 

13.22 

1.7(57 

3     11 

90.13 

12.048 

1       7 

14.73 

1.969 

4       0 

94.00 

12.566 

1       8 

•   16.32 

2.182 

4       1 

97.96 

13.095 

1       9 

17.99 

2.405 

4       2 

102.00 

13.635 

1     10 

19.75 

2.640 

4       3 

106.12 

14.186 

1     11 

21.58 

2.885 

4       4 

110.32 

14.748 

2       0 

23.50 

3.142 

4       5 

114.61 

15.321 

2       1 

25.50 

3.409 

4       6 

118.97 

15.90 

2       2 

27.58 

3.687 

4       7 

123.42 

16.50 

2       3 

29.74 

3.976 

4       8 

127.95 

17.10 

2       4 

31.99 

4.276 

4       9 

132.56 

17.72 

2       5 

34.31 

4.587 

4     10 

137.25 

18.35 

2       6 

36.72 

4.909 

4     11 

142.02 

18.99 

2       7 

39.21 

5.241 

5       0 

146.88 

19.63 

2.      8 

41.78 

5.585 

5       1 

151.82 

20.29 

2       9 

44.38 

5.940 

5       2 

156.83 

20.97 

2     10 

47.16 

6.305 

5       3 

161.93 

21.65 

2     11 

49.98 

6.581 

5       4 

167.12 

22.34 

3       0 

52.88 

7.069 

5       5 

172.38 

23.04 

3       1 

55.86 

7.467 

6       6 

177.72 

23.76 

3       2 

58.92 

7.876 

5       7 

183.15 

24.48 

3       3 

62.06 

8.296 

5       8 

188.66 

25.22 

3       4 

65.28 

8.727 

5       9 

194.25 

25.97 

LIQUID  SUBSTANCES 


95 


Diam  of 

No. 

Cub.  Ft. 

Diam 

of 

No. 

Cub.  Ft. 

Tanks 

U.  S. 

and  area 

Tanks 

U.  S. 

and  area 

Ft,  In. 

Gals. 

in  sq.  ft. 

Ft.  In. 

Gals. 

in  sq.  ft. 

5  10 

199.92 

26.73 

16 

9 

1648.40 

220.35 

5  11 

205.67 

27.49 

17 

0 

1697.90 

226.98 

6   0 

211.51 

28.27 

17 

3 

1748.20 

233.71 

6   3 

229.50 

30.68 

17 

6 

1799.30 

240.35 

6   6 

248.23 

33.18 

17 

9 

1851.10 

247.45 

6   9 

267.69 

35.78 

18 

0 

1903.60 

254.47 

7   0 

287.88 

38.48 

18 

3 

1956.80 

261.59 

7   3 

308.81 

41.28 

18 

6 

2010.80 

268.80 

7   6 

330.48 

44.18 

18 

9 

2065.50 

276.12 

7   9 

352.88 

47.17 

19 

0 

2120.90 

283.53 

8   0 

376.01 

50.27 

19 

3 

2177.10 

291.04 

8   3 

399.88 

53.46 

19 

6 

2234.00 

298.65 

8   6 

424.48 

56.75 

19 

9 

2291.70 

306.35 

8   9 

449.82 

60.13 

20 

0 

2350.10 

314.16 

9   0 

475.89 

63.62 

20 

3 

2409.20 

322.06 

9   3 

502.70 

67.20 

20 

6 

2469.10 

330.06 

9   6 

530.24 

70.88 

20 

9 

2529.60 

338.16 

9   9 

558.51 

74.66 

21 

0 

2591.00 

346.36 

10   0 

587.52 

78.54 

21 

3 

2653.00 

354.66 

10   3 

617.26 

82.52 

21 

6 

2715.80 

363.05 

10   6 

640.74 

86.59 

21 

9 

2779.30 

371.54 

10   9 

678.95 

90.76 

22 

0 

2843.60 

380.13 

11   0 

710.90 

95.03 

22 

3 

2908.60 

388.82 

11   3 

743.58 

99.40 

22 

6. 

2974.30 

397.61 

11   6 

776.99 

103.87 

22 

9 

3040.80 

406.49 

11   9 

811.14 

108.43 

23 

0 

3108.00 

415.48 

12   0 

846.03 

113.10 

23 

3 

3175.90 

424.56 

12   3 

881.65 

117.86 

23 

6 

3244.60 

433.74 

12   6 

918.00 

122.72 

23 

9 

3314.00 

443.01 

12   9 

955.09 

127.68 

24 

0 

3384.10 

452.39 

13   0 

992.91 

132.73 

24 

g 

3455.00 

461.86 

13   3 

1031.50 

137.89 

24 

6 

3526.60 

471.44 

13   6 

1070.80 

143.14 

24 

9 

3598.90 

481.11 

13   9 

1110.80 

148.49 

25 

0 

3672.00 

490.87 

14   0 

1151.50 

153.54 

25 

3 

3745.80 

500.74 

14   3 

1193.00 

159.48 

25 

6 

3820.30 

510.71 

14   6 

1235.30 

165.13 

25 

9 

3895.60 

520.77 

14   9 

1278.20 

170.87 

26 

0 

3971.60 

530.93 

15   0 

1321.90 

176.71 

26 

3 

4048.40 

541.19 

15   3 

1366.40 

182.65 

26 

6 

4125.90 

551.55 

15   6 

1411.50 

188.69 

26 

9 

4204.10 

562.00 

15   9 

1457.40 

194.83 

27 

0 

4283.00 

572.66 

16   0 

1504.10 

201.06 

27 

3 

4362.70 

583.21 

16   3 

1551.40 

207.39 

27 

6 

4443.10 

593.96 

16   6 

1599.50 

213.82 

27 

9 

4524.30 

604.81 

96 


LIQUID  SUBSTANCES 


Diam  of 

No. 

Cub.  Ft. 

Diam  of           No. 

Cub.  Ft. 

Tanks 

U.  S. 

and  area 

Tanks 

U.  S. 

and  area 

Ft.  In. 

Gals. 

in  sq.  ft. 

Ft.  In. 

Gals. 

in  sq.  ft. 

28       0 

4606.20 

615.75 

30       9 

5555.40 

742.64 

28       3 

4688.80 

(326.80 

31       0 

5646.10 

754.77 

28       6 

4772.10 

637.94 

31       3 

5737.50 

766.99 

28       9 

4856.20 

649.18 

31       6 

5829.70 

779.31 

29       0 

4941.00 

660.52 

31       9 

5922.60 

791.73 

29       3 

5026.60 

671.96 

32       0 

6016.20 

804.25 

29       6 

5112.90 

683.49 

32       3 

6110.60 

816.86 

29       9 

5199.90 

695.13 

32       6 

6205.70 

829.58 

30       0 

5287.70 

706.86 

32       9 

6301.50 

842.39 

30       3 

5376.20 

718.69 

31^ 

gallons  equal 

1  barrel. 

30       6 

5465.40 

730.62 

NOTE:  To  find  the  capacity  of  tanks  greater  than  the  largest  given 
in  the  table,  look  in  the  table  for  a  tank  of  one-half  of  the  given  size 
and  multiply  its  capacity  by  4,  or  one  of  one-third  its  size  and  multiply 
its  capacity  by  9,  etc. 


CO-'  AND  FUEL  LOSSES. 
CALCULATED  ON  FOLLOWING  CONDITIONS: 

Oil  as  used  for  fuel— 18633  B.  T.  U.,  84.73%  carbon,  11.74%  hydrogen, 
1.06%  sulphur,  5%  nitrogen,  .87%  oxygen,  .7%  moisture  and  .4%  sedi- 
ment. 

Atmospheric  temperature  55%  F.,  humidity  88,  exhaust  temperature 
500°  F.,  Kern  Oil  16°  B. 


Per  Cent 


15.6 

15 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 


Per   Cent 

Excess 

Air 

0 

5 

10 

18 

28 

40 

54 

70 

93 

120 

152 

198 

273 

396 

635 


B.  T.  U. 

Per  Cent 

Loss 

Preventable 

Fuel  Loss 

0 

.0 

75 

.4 

186 

1. 

317 

1.7 

447 

2.4 

633 

3.4 

856 

4.6 

1118 

6. 

1435 

7.8 

1900 

10.2 

2460 

13.2 

3205 

17.2 

4380 

23.5 

6340 

34. 

10150 

54.5 

LIQUID  SUBSTANCES 


97 


METRIC  CONVERSION  TABLE  (LIQUIDS) 
Weight  of  Water 

Weight  of  one  cubic  foot  of  pure  water: 

At    32°    F.  =62.418  Ibs. 

At    39.1°  F.  (max.  dens.)       =62.425  Ibs. 
At    62°    F.  =62.355  Ibs. 

At  212°    F.  =59.75     Ibs. 


CONVERTING     SPECIFIC     GRAVITY     INTO     DEGREES     BAUME     AND 

VICE   VERSA 

For  liquids  lighter  than  water; 


140 
'Baume — 


=  130 


sp.  gr.  60°/60°  F. 
Sp.  gr.  60°/60°  F.  =  140 


For  liquids  heavier  than  water: 
°Baume  =  145  — 


130  +  °Baume 


145 


Sp.  gr.  60°/60°  F. 
Sp.  gr.  60°/60°F.=  145 


145  —  °Baume 


ORIGIN,  SPECIFIC  GRAVITY,  ETC.,  OF  OILS 


Name  Type 

Cylinder  "A"__     Mineral 

Cylinder  "Cold  Test"_  Mineral 

Castor  Oil Vegetable 

Lard   Oil Animal 

Neatsfoot Animal 

Olive  Oil Vegetable 

Pale  Oil Mineral 

Sperm  Oil Fish 

Valve  Oil    (light) Mineral 

Valve  Oil   (dark) Mineral 

Colza Vegetable 

Stearine__  ..  Animal 


Spec.  Grav. 

Viscosity 

Color 

894 

146-f 

Brown  black 

886 

116-f 

Reddish  green 

963 



White 

915 

913 

916 

865 

50 

875 

White 

887 

149  + 

Light  yellow 

887 

152+ 

Greenish  brown 

914 



White 

„ 

^ 

White  gray 

98  LIQUID  SUBSTANCE'S 

MEASUREMENT  BASED  ON    U.  S.  GALLONS 

1  U.  S.  Gallon  =  231  cubic  inches 

=  0.133  cubic  feet, 

=  8.3356  pounds  at  62°  F. 
1  cubic  ft.  —  7.48  U.  S.  Gallons. 
1  Imperial  Gal.  =  1.2  U.  S.  Gallon. 

Weight  of  a  Cubic  Foot  of  Water,  English  Standard,  62.321  pounds 
Avoirdupois. 


LIQUID    MEASUREMENT 

1  cubic  foot   of  water ___  =  62.3791  Ibs. 

1  cubic    inch   of   water —  .03612  Ibs. 

1  gallon  of  water ___  =  8.338  Ibs. 

1  gallon  of  water =.  231.  cubic  in. 

1  cubic  foot  of  water =.  7.481  gallons. 

1  pound  of  water =  27.7  cubic  in. 

1  cubi<c    meter    =  264  gallons. 

1  Imperial  gallon =  1.2  gallons   (U.  S.) 

1  acre    foot _  =  326,000  gallons. 

1  pound    —  .12  gallons. 

1  pound    pressure    =  2.31  ft.  head. 

1  atmosphere    =  34  ft.  head 

1  inch   of   mercury —  1.134  ft.  head 

1  meter     =  3.281  ft.  head. 

1  cubic  foot  per  second =  449  G.  P.  M. 

1,000,000  gallons  per  day =  695  G.  P.  M. 

1  miner's   inch    (California  and  Arizona) =  11.2  G.  P.  M. 

1  miner's   inch    (Utah,   Idaho,  Montana,  Nevada, 

New   Mexico,  Oregon  and  Washington) =  9  G.  P.  M. 

1  miner's   inch    (Colorado) _  —  11.7  G.   P.  M. 

1  cubic  meter  per  hour =  4.22  G.  P.  M. 

100  liters  per  hour —..411  G.  P.  M. 

1  liter  per  second —  15.852  G.  P.   M. 

1000    per    hour =  2  G.  P.  M. 

TABLE    EQUIVALENT    FOR    FUEL    OIL 
SPECIFIED   DIESEL    ENGINE    FUEL   OIL 

When  procuring  Fuel  Oil  for  Diesel  Engines,  an  oil  for  fuel  purposes 
should  possess  the  following  specifications: 

Gravity 23  to  25  Baume 

Specific  Gravity .917  to  .905 

Flash,  Closed  .200  minimum 

Viscosity   70  degrees  Fahr.  —  650  sec.  max. 

Sulphur    y2   maximum 

When  "light  distillate  oil"  is  desired,  the  Gravity  should  be  at  its 
maximum  30.0  to  35.0  and  150  degree  Fahr.  min.  Flash, 


LIQUID  SUBSTANCES  99 

TABLE    OF    SOLID    LIQUIDS,    SHOWING    TEMPERATURES 

Temp.  Per  Specific  Flash 

(Fahr.)                   Distillate  Cent  Gravity  Point 

Degrees  (Fahr.) 

Commercial   Gasoline 

250-350                     Kerosene,  light  10  .73                    50 

160-250                    Benzine,  naphtha  10  .70                    14 

140-160                    Gasoline,   normal  2  .65                    10 

400  Kerosene,    heavy  10  .89  270 

350  Kerosene,  medium  35  .80  150 

482  Lubricating  Oil  10  .905                315 

«* 

NOTE:  While  there  is  a  great  variation,  depending  on  values  ob- 
tainable among  the  different  petroleum  products,  nevertheless  figures 
given  on  this  table  are  the  average. 


DENSITY  OF  OIL 

The    following   table   gives    the   specific   gravity   and    weight    of   oil 
corresponding  to  readings  on  Baume  Scale: 

Degree         Specific           Pounds               Degree  Specific  Pounds 

Baume        Gravity           Per  Gal.              Baume  Gravity  Per  Gal. 

12                 .986                   8.22                      24  .913  7.61 

14                 .973                   8.11                      26  .901  7.51 

16                 .960                   8.00                      28  .890  7.42 

18                 .948                   7.90                      30  .880  7.33 

20                 .936                   7.80                      32  .869  7.24    . 
22                 .924                   7.70 


HEAT  OF  VAPORIZATION 

In  the  following  table,  the  heat  of  vaporization  is  given  of  various 
liquids  (at  atmospheric  pressure,  except  when  otherwise  specified) : 

Alcohol    (ethyl)    208.92  cal. 

Ammonia    (NH^) 294.21,  (at  7.8°) 

Benzol     .__  93.45 

Bromine 45.60 

Carbon    dioxide    56.25   (at  0°) 

Carbon    disulphide    86.67 

Chloroform     58.49 

Ether  (COIio) 91.11 

Iodine    23.95 

Mercury 62.00 

Sulphur    dioxide    .    91.7     (at  0°) 

Water  __535.9 


100  LIQUID  SUBSTANCE'S 

CORRESPONDING   VALUES  OF  SPECIFIC  GRAVITY,   DEGREES 
BAUME  AND  WEIGHT 


Nearest 

Nearest 

Specific 

Degree  on 

Pounds  per 

Specific 

Degree  on 

Pounds  per 

Gravity 

the  Baume 

Gallon 

Gravity 

the  Baume 

Gallon 

Scale 

Scale 

0.70 

70 

5.84 

0.86 

33 

7.17 

0.71 

67 

5.92 

0.87 

31 

7.25 

0.72 

65 

6.00 

0.88 

29 

7.34 

0.73 

62 

6.09 

0.89 

27 

7.42 

0.74 

59 

6.17 

0.90 

26 

7.50 

0.75 

57 

6.25 

0.91 

24 

7.58 

0.76 

54 

6.34 

0.92 

22 

7.67 

0.77 

52 

6.42 

0.93 

21 

7.75 

0.78 

50 

6.50 

0.94 

19 

7.84 

0.79 

47 

6.59 

0.95 

17 

7.92 

0.80 

45 

6.67 

0.96 

16 

8.00 

0.81 

43 

6.75 

0.97 

14 

8.08 

0.82 

41 

6.84 

0.98 

13 

8.17 

0.83 

39 

6.92 

0.99 

11 

8.25 

0.84 

37 

7.00 

1.00 

10 

8.34 

0.85 

35 

7.09 

CALORIFIC    VAULES    OF    THE    PRINCIPAL    CONSTITUENTS 
(LIQUID  SUBSTANCES) 

Volumetric  Expansion 
Liquids  Centigrade     Fahrenheit 

Acid,    nitric    .110  .061 

Acid,    sulphuric    .063  .035 

Alcohol     .104  .058 

Mercury     .018  .010 

Oil,    turpentine    .  .090  .050 


DIFFERENCE   IN   FUEL  CONSUMPTION   ON   HIGH   ALTITUDES: 

As  the  elevation  above  sea  level  increases,  the  pressure  of  the  at- 
mosphere and  consequently  the  weight  of  the  air  drawn  into  the  cyl- 
inder decreases.  This  in  turn  reduces  the  amount  of  fuel  which  can  be 
consumed  and  thereby  the  power  of  the  engine. 

The  reduction  is  about  three  and  one-half  per  cent  for  each  thousand 
feet  (305  meters)  elevation  above  sea  level  and  occurs  with  all  internal 
combustion  engines.  For  example: 

For  an  engine  to  operate  at  an  elevation  of  6,000  feet,  the  reduc- 
tion would  be  .035  X  6,  or  .21.  Thus  an  engine  rated  at  100  H.  P.  at  sea 
level  would  be  rated  at  79  H.  P.  at  6,000  feet  elevation.  For  altitudes 
under  one  thousand  feet  (305  meters),  no  reduction  in  the  rating  of  the 
engine  is  made. 


LIQUID 


101 


PETROLEUM   SUBSTANCE. 

The  only  natural  liquid  fuel  is  crude  petroleum  oil.  This  is  distinctly 
a  hydro-carbon  liquid,  and  is  found  in  abundance  in  certain  localities  in 
America  and  Europe,  as  well  as  some  sections  of  Asia. 

The  principal  sources  of  supply  are,  however,  in  the  Ohio  Valley 
of  -the  United  States,  on  the  borders  of  the  Caspian  Sea  in  Eastern 
Europe,  and  Western  Asia.  It  is  found  principally  in  porous  sandstones, 
but  also  in  natural  cavities  beneath  the  earth's  surface,  whence  it  is 
either  pumped,  or  flows  to  the  surface  after  the  manner  of  operation  of 
an  artesian  well. 

Crude  petroleum  is  dark  brown  in  color,  with  a  perceptible  greenish 
tinge,  and  has  a  specific  gravity  which  averages  about  0.8.  It  is  composed 
of  a  great  number  of  liquid  hydro-carbons,  varying  widely  in  specific 
gravity  and  chemical  composition,  and  each  seperable  from  the  others 
by  fractional  distillation.  The  ultimate  analysis  of  an  average  sample  in- 
dicates about  the  following  composition: 

Carbon 84  per  cent 

Hydrogen 14     "         " 

Oxygen..  2     " 


100  per  cent 

Allowing  for  the  combination  of  the  inherent  oxygen,  with  its  equiva- 
lent of  hydrogen  to  form  water,  the  practical  composition  becomes: 

Carbon 84        per  cent 

Hydrogen 13.75     " 

Water   _  2.25     " 


100       per  cent 

The  heat  value  of  a  pound  of  petroleum  of  the  above  composition  is, 
therefore: 

Carbon 0.84X14.650=12.306  B.  T.  U. 

Hydrogen  _  __0.1375X  62,100—  8.539  B.  T.  U. 


20.845  B.  T.  U. 

PHYSICAL  PROPERTIES  OF  OIL 

Classification  of  oils  according  to  their  density  is  very  commonly 
used  to  denote  other  characteristics.  When  alluding  to  "heavy"  oils,  we 
term  it  "viscous"  and  sluggish  with  a  high  percentage  of  asphalt  and 
comparatively  low  heat  value,  while  a  light  oil  is  supposed  to  be  very 
"fluid"  at  ordinary  temperatures,  very  volatile  and  rich  in  the  lighter 
hydro-carbons  and  high  in  heat  value.  While  in  general,  these  character- 
istics hold  true  enough  to  explain  the  prevalent  associations  of  ideas, 
there  are  so  many  exceptions  and  variations  that  it  is  essential  to  clearly 
specify  the  various  properties  of  a  particular  oil  in  order  to  identify  it. 


102 


LIQUID  SUBSTANCE'S 


EXPANSION  OF  WATER,  MAXIMUM   DENSITY  =  1 


C°  Volume 

0   __________      __-   1.000126 

4   ________________   1.000000 

10  _          .__  1.000257 
20  ________________  1.001732 

30  __          .  1.004234 


40  _ 


1.007627 


C°  Volume 

50 1.011877 

60     1.016954 

70 ___  1.022384 

80  .  .__  1.029003 

90  __-  1.035829 

100  _  -  1.043116 


COAL  TARS  AND  COMPOSITION: 

Water Should  not  exceed  1  per  cent. 

Sulphur iShould  be  about  .5  to  1  per  cent. 

Ash Should  not  exceed  1  per  cent.  (Ingredients  in  un- 

burnt  quantities  are  harmless). 

Pitch Tar  oils  which  contain  a  high  percentage  of  residue 

beginning  to  vaporize  at  400°  €.,  the  same  results 
can  be  expected  as  with  tar;  in  this  instance  the  re- 
sult will  be  the  settling  of  considerable  foreign  mat- 
ter in  the  engine  with  the  consequential  requirement 
of  cleaning  and  grinding  of  exhaust  valves. 

Specific  Gravity Usually  between  1.0  and  1.1. 

Color While  tar  oils  generally  show  dark  black  color,  nev- 
ertheless with  the  intermix  of  lighter  ingredients 
a  dark  brown  color  is  often  found.  Black  residue 
signifies  a  large  percentage  of  carbon  or  other 
heavy  solving  substances  making  up  the  composition 
of  tar. 

Flashpoint Usually  between  10°  F.  and  130°  F. 

Viscosity On  an  average  2°  Engler. 

HEAT  VALUES  OF  VARIOUS  OILS 

Specific  Per  Ib.  Authority 

Gravity  B.  T.  IT. 

California— Coalinga  Field 0.927  17.177  Bashore 

Bakersfield 0.992  18.257  Wade 

Kern    River 0.950  18.854  Bashore 

Los  Angeles 0.977  18.280  Bashore 

Monte   Christo 0.966  18.878  Bashore 

Whittin 0.936  18.240  Wade 

Texas — Beaumont 0.924  19.060  U.    S.    Navy 

Beaumont 0.903  19.349  Bashore 

Sabine 0.937  18.662  Bashore 

Pennsylvania 0.886  19.210  Booth 

Mexico 0.921  18.840  Bashore 

Mexico__  0.981  17.551  Bashore 


LIQUID  SUBSTANCES  103 

CALORIFIC    VALUES    OF    THE    PRINCIPAL    CONSTITUENTS 
OF   FUELS: 

The  table  below  gives  the  calorific  values  of  the  principal  const it> 
uents  of  fuels  for  Diesels.  The  values  noted  "at  constant  pressure"  are 
alluding  to  such  types  of  machinery  where  constant  pressure  is  the  factor 
to  be  considered.  The  values  in  this  table  are  based  on  those  determined 
by  Berthelot,  Thomson,  and  others. 


Table  of  Calorific  Values  of  the  Principal  Constituents  of  Fuels: 

At  constant  pressure  At  constant  volume 

Combustible                          C.  H.  U.     B.  T.  U.  C.  H.  U.     B.  T.  U. 

Hydrogen     34500         62100  34095         61371 

Carbon  burned  to  COo—       8100         14580  8100         14580 

Carbon  burned  to  C0__           2416           4349  2416           4349 

Carbon    monoxide     (CO)_       2436           4385  2426           4367 

Methane    (CH4)    13344         24019  13276         23897 

Ethylene    (GgH4)     12182         21928  12143         21857 

Sulphur    .              2300           4140  2300           4140 


CHAPTER  VI. 


QUESTIONS  AND   ANSWERS   ON    DIESEL    ENGINE    OPERATION: 

1.  Give   a    Brief    Definition   of  a   Diesel    Engine: 

The  Diesel  engine  is  a  machine  which  generates  its  motive  power 
by  the  process  of  combustion.  Its  Ignition  system  is  compressed  air. 
The  burning  of  solid  liquid  sprayed  in  the  cylinder  creates  a  constant 
pressure,  etc.  etc. 

2.  How    is    the    Diesel    Engine    Classified    in    Regards    to    Construction? 
The  two   stroke  cycle,   commonly  known   ais  the   two-cycle    and    the 

four-<stroke  cycle,  known  as  the  four-cycle. 

3.  Define  the  Meaning  of  Mechanical    Efficiency  of  the   Engine: 

This  applies  to  the  ratio  between  the  brake-horse  power  and 
actual  power  'developed  in  the  cylinder. 

4.  What    is    the    Indicated    Brake    Thermal     Efficiency? 

The  percentages  of  the  heat  units  of  the  fuel  that  -the  engine  is 
capable  of  transferring  into  indicated  or  effective  work;  or  the  ratio 
between  the  equivalent  of  the  horse  power  in  heat  units  and  the  number 
oif  heat  units  which  the  engine  requires  to  develope  one  I.  H.  P.  or  one 
B.  H.  P. 

5.  Define   the   Volumetric   Efficiency    in   a    Four-cycle    Engine: 

The  ratio  between  the  weight  of  the  air  contained  in  the  cylinder 
at  the  commencement  of  compression  stroke  and  that  required  to  fill  the 
same  Volume  with  air  at  atmospheric  pressure. 

6.  What   is  Meant   by  the   Scavenging    Efficiency   in  a   Cycle? 

The  ratio  between  the  weight  o<f  air  in  the  cylinder  at  the  com- 
mencement of  the  compression  stroke  and  that  of  the  mixture  of  air 
and  burned  gases. 

7.  What   is    Necessary  to    Maintain    a    Diesel    Engine? 
Fuel,  Ignition,  Water-Cooling  and  Lubrication. 

8.  Explain   the  Working    Principle  of  a    Four-cycle    Diesel    Engine. 
During  the  first  downward  stroke  the  piston  draws  air  through  the 

suction  valve;  during  the  return  stroke  the  suction  valve  and  every 
other  communication  with  the  atmosphere  is  closed  and  the  air  in  the 
cylinder  is  compressed.  Toward  the  end  of  the  stroke  the  fuel  pump 
injects  into  the  cylinder  the  quantity  of  oil  necessary  for  the  combus- 
tion stroke,  so,  that  when  the  piston  arrives  on  the  dead  center  the 


QUESTIONS  AND  ANSWERS  105 

fuel  burns  rapidly,  raising  the  temperature  and  the  pressure  in  the 
cylinder.  During  the  next  downward  stroke  of  the  piston  the  burned 
gases  are  expanded,  producing  useful  work.  During  the  fourth  stroke 
the  piston  sweeps  out  the  burnt  gases  into  'the  atmosphere  through 
the  open  valve,  after  wlhich  the  cycle  recommences. 

•V    9.     How     Much     Pressure     is     Necessary     in     Supplying     Cylinders    with 
Fuel  Oil? 

The  pressure  necessary  for  fuel  injection  varies  with  the  load 
andi  the  type  of  the  engine,  but  is  seldom  lower  than  540  pounds  to  the 
square  inch,  nor  higher  than  1005  pounds  per  square  inch. 

10.  State   the   Process  of   Injecting    Fuel    in   the   Cylinders. 

The  pumping  /method  is  exclusively  adopted.  This  owing  to  the 
fact,  that  a  force^feed  system  is  necessary  exerting  a  pressure  in  ex- 
cesis  with  the  existing  pressure  in  the  cylinder. 

11.  Explain   the    Function   of   the    Fue^-injection    Valve. 

The  fuel-injection  valve  is  one  of  the  characteristic  parts  of  the 
Diesel  engine.  Its  if  unctions  are  \two-lold:  first,  that  of  a  valve  to  intro- 
duce the  fuel  oil  into  the  cylinder  at  the  correct  moment;  and,  second, 
that  of  a  sprayer  to  divide  the  fuel  into  minute  particles. 

12.  What  are  the  Duties  of  a  Compressor  on  a   Diesel   Engine? 

The  duties  of  ithe  Compressor  on  Diesel  Engines  are  to  supply 
high  pressure  necessary  ifor  the  injection  of  the  fuel  oil  into  the 
working  cylinders  during  the  running  of  the  engine,  and  to  supply  air 
for  storage  purposes  into  cylindrical  steel  reservoirs. 

13.  What    are    Reservoirs    of    Cylindrical    Form    Called    and    What    are 
They    Intended    For? 

They  are  called  the  starting  bottles  and  act  as  a  storage  reserve 
power  connected  to  cylinders  through  a  system  of  yalyes  and  pipes. 

14.  How    Much  Air   is   Usually    Required   to   Start   Engine? 
Depending  on    the    size   and    respective    type    of    engine. 

15.  How  is  a  Compressor  Constructed? 

In  two  or  three  stages,  between  each  af  which  the  air  is  cooled 
by  passing  throuigih  a  reservoir  of  water. 

16.  What  advantages  are  there  by  Using  Multiple  Stage  Compressors? 
The    multiplication    of    the    stages    of    compression    improves    the 

volumetric    efficiency    of   the    compressor    and    diminishes    the    amount 
of  -work  absorbed  besides  allowing  of  better  cooling  of  the  air. 

17.  What  is  a   Scavenging   Pump? 

The  function  of  the  scavenging .  pump  is  to  compress  air  to 
a  low  pressure  to  free  the  working  cylinders  of  two-cycle  engines  of 
the  exhaust  gases,  to  be  charged  afresh  with  jpure  air  for  the  next 
combustion  stroke. 


106  QUESTIONS  AND  ANSWERS 

18.  Can  Scavenging  be   Effected   Without  Valves? 

Yes,  there  is  nothing  to  prevent  the  scavenging  being  effected  with- 
out valves,  as  described  for  explosion  engines,  and  applied  in  some 
Diesel  engines,  more  especially  for  low  powers.  Scavenging  with 
valves  is  more  complete  in  its  effect,  and  the  weight  of  air  which  re- 
mains in  ithe  cylinders  is  greater.  When  the  scavenging  is  carried 
out  by  means  of  single  ports,  the  latter  are  closed  'before  those  of 
the  exhaust,  and  iso  the  pressure  in  the  cylinder  is  no  greater  -than  that 
of  the  atmosphere.  On  the  other  hand,  with  valve  scavenging  the 
valves  are  closed  after  the  piston  has  covered  the  exhaust  ports,  and 
so  the  pressure  of  the  air  in  the  cylinder  before  the  compression 
stroke  commence'S  is  that  given  by  the  scavenging  pump,  between  3 
and  7  pounds  per  square  inch. 

19.  Why  is  the   Diesel    Engine  Classified   as  Constant  Pressure   Engine? 
Mechanical     means    are    adopted     for    obtaining     pulverization     or 

spraying  by  assistance  of  an  injection  device,  the  heavy  fuel-oil  into 
the  cylinder  by  means  of  a  current  of  air  at  a  pressure  considerable 
higher  than  that  present  in  the  cylinder  itself;  thus  the  fuel  is  sub- 
divided into  minute  particles  and  forms  a  kind  of  mist.  If  the  air 
in  ithe  Cylinder  /at  ithe  instant  when  the  injection  takes  place  is  at 
a  sufficiently  high  temperature,  the  mist  of  oil  spontaneously  ignites, 
and  the  combustion  lasts  the  whole  time  during  which  the  oil  con- 
tinues to  enter,  assuming  the  character  of  gradual  combustion  as  oppos- 
ed ito  explosion.  In  this  way  the  combustion  takes  place  in  "Constant 
Pressure"  or  -Diesel  Engines. 

20.  Why    are     Heavy    Oil     Engines    Classified    as     Internal    Combustion 
Engines? 

Heavy  oil  engines  convert  the  heat  energy  of  the  fuel  into  the 
engine  cylinder  itself.  The  heavy  oil,  injected  into  the  cylinder  in  a 
suitable  'condition,  ignites,  burning  with  the  oxygen  of  the  air  therein, 
and  so  evolves  heat. 

21.  Why   are  a  Great    Many   Engines    Equipped    With  Only   One  or  Two 
Air  Starters? 

As  a  rule,  only  one  or  two  cylinders  of  a  multi-cylinder  engine 
are  provided  with  -starting  valves,  thus  reducing  the  cost  of  the  engine 
In  some  engines  automatic  means  are  provided  for  keeping  the  exhausi 
valves  open  during  starting,  compression  being  avoided  until  the  engine 
is  well  up  to  or  past  its  normal  speed  to  s'ave  compressed  air  in  start- 
ing. Some  engines  have  a  blow-off  cock  in  the  head  of  tne  cylinder, 
which  is  kept  open  for  a  time  in  starting;  this  is  also  used  to  blow 
off  inimical  'substances. 

22.  Explain  the  Working  of  "Air-operated  Piston  Valves." 

In  some  construction  "mechanically  operated"  starting  valves 
are  eliminated,  independent  air-operated  piston  valves  being  substi- 
tuted. These  receive  the  starting  air  ithrough  a  rotary  distributor 


QUESTIONS  AND  ANSWERS  107 

operated  by  the  cam-shaft.  The  rotary  distributor  can  be  connected 
or  disconnected  when  the  engine  is  running  or  is  at  rest.  The  fuel 
valve  likewise  is  thrown  in  iby  a  central  control.  This  'Construction 
eliminates  the  cam  and  the  fulcrumed  lever  for  each  starting  valve 
used  with  the  other  tyipes. 

23.  Explain    the    Functioning    of    "Actuating    Valves." 

The  time  of  opening  and  closing  of  the  different  valves  of  Diesel 
engines  musit  be  accurately  controlled;  they  are  therefore  not  self- 
acting  but  are  operated  mechanically. 

24.  Explain   the   System   of  "Rocking    Levers   and   Cam." 

The  usual  method  of  actuating  the  valves  on  Diesel  engines 
is  through  a  system  of  rocker  lever  and  cams;  the  latter  are  mounted 
on  a  horizontal  shaft  near  the  top  of  the  cylinders.  The  cam  shaft 
is  driven  through  a  set  of  helical  gears,  running  in  oil.  by  a  vertical 
shaift  which  in  turn  is  driven  through  another  set  of  helical  gears  from 
the  engine  shaift.  The  vertical  shaft  has  the  same  speed  as  the  main 
shaft;  the  <cam  shaft  runs  at  half  the  speed  of  the  main  shaft  in 
engines  having  a  four-stroke  cycle  and  at  the  same  speed  as  the  main 
shaft  in  engines  having  a  itwo-stroke  cycle.  The  (governor,  usually  of 
the  through-shaft  type,  is  mounted  on  the  vertical  shaft,  as  this  has 
the  'higher  speed.  This  arrangement  permits  the  use  of  a  smaller 
governor  of  the  standard  type. 

25.  How  Are  Pistons  on  Diesel    Engines  Water-cooled? 

The  water  (for  piston  cooling  may  be  circulated  through  teles- 
copic pipes,  with  the  stuffing  box  a  moving  part  of  the  piston,  or  the 
stuffing  box  may  be  attached  to  the  frame  and  the  water  be  supplied  to 
the  piston  through  hollow  walking  arms  through  which  the  water  flows 
through  the  pipes  leading  to  the  piston.  A  pump  may  be  actuated  from 
the  crosshead  and  the  water  be  carried  to  the  piston  through  the 
hollow  piston  rod.  In  another  cooling  system  water  is  sprayed  by  air 
against  the  heated  piston  surface,  not  enough  water  being  used  to  fill 
the  water  <space  of  the  ipiston.  The  excess  water  drains  off  through  a 
pipe  surrounding  the  spray  pipe,  no  stuffing  box  being  used. 

26.  Is  the  Trunk-piston  Preferrable  to  the  Cross-head? 

The  trunk  piston  is  more  easily  provided  with  a  greater  bearing 
surface  than  a  cro&s-head ;  thus  insuring  less  wear.  The  lubrication 
under  pressure  of  a  cylindrical  guiding  surface  is  more  effective  tihan 
with  open  guides.  The  piston  moves  over  perfectly  cooled  walls,  where- 
as the  cross-heads  tend  to  heat  more  readily  and  when  once  hot  is 
not  easily  cooled;  moreover,  water-cooled  cross-heads  complicate  con- 
struction. For  large  engines  this  construction  is  used,  as  it  affords 
greater  accessibility  and  ease  of  adjustment,  the  cross-head  guides  in 
such  engines  'being  water-cooled. 


108  QUESTIONS  AND  ANSWERS 

27.  What   Are   the    Usual    Methods    in    Lubricating   Cylinders   on    Diesel 
Engines? 

The  'cylinders  are  lubricated  by  providing  each  cylinder  with 
a  force-feed  pump  operated  by  a  reducing  motion  from  the  end  of  the 
piston  or  with  a  multiple-plunger  pump  driven  by  an  eccentric  device 
direct  from  the  cam  shaft,  one  plunger  being  provided  for  each  work- 
ing cylinder  and  one  for  each  air-compressor  cylinder.  In  some  en- 
gines two  plungers  per  cylinder  are  provided,  one  for  each  pair  of 
the  four  oil  feeds  grouped  around  the  cylinder.  Two-stroke  Diesel 
engines  usually  have  separate  oil  feed  above  and  below  the  exhaust 
ports  to  prevent  any  excess  of  lubricating  oil  from  being  swept  through 
the  exhaust  ports. 

28.  Explain  the   Retarding    Method   of   Injecting  Air  and    Fuel. 

In  the  cylinder  of  large  engines  the  .fuel  needle  can  be  so  governed 
that  the  entrance  of  ithe  injection  air  and  fuel  into  the  combustion 
space  is  retarded  and  gradual,  preventing  excessive  use  of  injection 
air  cooling  of  the  atmosphere  at  the  point  when  the  ignition  must 
be  maintained.  By  these  means  tar  oil  can  be  ignited  without  the  use 
of  ignition  oil.  To  remove  the  fuel  needle  from  the  valve  it  is  neces- 
sary in  some  constructions  to  remove  the  nut  holding  the  spring  bonnet 
and  cap  into  place,  as  well  as  the  two  nuts  that  fix  the  position  of  the 
rocker  arm  through  which  the  needle  valve  is  actuated. 

Construction  that  facilitates  the  removal  of  the  fuel  needle  is  of 
decided  advantage,  'as  the  valve  needle  has  to  be  removed  when  it 
has  to  -be  ground  and  frequent  grinding  is  necessary.  Fuel  needles 
have  to  be  ground  weekly  or  monthly,  depending  on  the  quality  of  the 
fuel  oil.  The  use  of  oils  with  high  ash  contents  necessitates  more 
frequent  grinding  of  the  needle.  The  needle  is  turned  back  and  forth 
in  its  seat,  a  small  quantity  of  emery  dust  and  oil  should  be  used. 

29.  Explain  the  Construction  of  Valve   Attachment. 

Connections  of  the  copper  seamless  steel  tubing  used  for  carrying 
the  air  and  fuel  under  high  pressure  are  made  with  joining  the  ends  of 
the  pipes  to  a  copper  shank  terminating  in  a  cone  which  fits  into  a 
tapered  seat  machined  out  of  the  body.  A  steel  gland  nut  slipped  over 
the  'copper  ishank  is  pressed  against  the  cone  to  seal  the  seated  con- 
nection. To  seal  the  air  chamber  of  the  fuel  valve  and  prevent  leak- 
age of  air  around  the  valve  needle,  lead  or  babbit  metal  shavings 
mixed  with  flaked  graphite  are  used  as  packing  material,  secured  by 
appropriate  glands,  a  series  of  labyrinth  grooves  on  the  valve  needle 
constitutes  an  added  precaution  against  serious  leaks. 

30.  At   What    Degree   does    Timing    Usually    Occur? 

The  time  at  which  the  different  valves  are  opened  or  closed 
differs  widely  with  different  makes  of  engines.  The  air  valve  opens 
15  degrees  to  20  degrees  before  the  piston  reaches  the  top  dead  cen- 
ter, and  closes  15  to  20  degrees  past  the  bottom  center,  being  open 


QUESTIONS  AND  ANSWERS  109 

a  total  period  of  210  to  220  degrees.  The  fuel  valves  open  2  degrees 
to  8  degrees  before  the  piston  reaches  -the  top  center,  and  closes  18 
to  36  degrees  after  the  piston  has  passed  the  top  center,  being  open 
20  degrees  to  44  degrees.  The  exhaust  valves  open  25  to  45  degrees 
before  the  piston  reaches  the  bottom  center,  and  closes  8  to  14  degrees 
after  the  piston  has  passed  the  top  center. 

It  should  be  taken  in  consideration,  that  the  type  of  fuel  valve 
and  the  properties  of  the  liquid  fuel  burned,  greatly  influences  the 
timing  of  the  (fuel  valves. 


CAUSES    AND    EFFECTS    IN    THE    PRINCIPLE    OF    OPERATION    OF 
DIESEL    ENGINES    AND    REMEDIES. 

1.  What  is  the   Maximum    Piston    Travel  iPer    Minute  and    R.    P.   M. 
Similar    to    the    Steam    Reciprocating    Engine,    the    Diesel    Engine 

is  rated  in  piston  travel  to  1500  feet  per  minute.     Its  revolutions  per 
minute  are  rated  with  rare  exceptions  up  to  400  R.   P.  M. 

2.  How  Should   Valves   Be  Set  on   Diesel    Engines? 

To  set  the  spray,  intake  and  exhaust  valve,  first  know  that  shafts 
are  in  their  proper  position.  Adjust  cam  roller  clearances;  giving 
the  exhaust  about  .30  degree,  intake  about  .025  degree  and  spray  about 
.018  degree. 

Jack  engine  ahead  until  the  pointer  on  the  after  end  of  the 
housing  is  in  line  with  some  graduation  on  the  fly-wheel  that  is 
marked  for  the  opening  of  some  valve.  When  the  engine  is  in  the  po- 
sition where  some  valve  should  open,  the  cam  roller  for  that  valve 
should  be  just  starting  on  the  cam;  and  if  not,  adjust  the  roller  by 
screwing  in  or  out  on  adjusting  screw  in  upper  end  of  rocker  arm. 
Proceed  on  all  other  valves  the  same  as  the  first.  After  setting  of 
all  valves  go  over  roller  clearance  once  more.  After  final  adjustment 
no  roller  should  be  left  on  the  cam  or  close  enough  that  the  expansion 
of  the  valve  stem  will  cause  the  roller  to  ride  the  cam.  This  applies 
specially  to  the  exhaust,  because  that  valve  gets  more  heat  than  any 
of  the  others.  All  relief  valves  are  set  by  connecting  them  to  a  hy- 
draulic testing  machine  and  adjusted  to  open  at  their  required  pres- 
sure. 

(Note:      Above  rule   for   setting   valves   is   identical  with   almost   every 
type  of  Diesel  Engine,  differing  in  minor  details). 

3.  What  May  Cause  the   Engine  to  Slow  Down? 

Water  in  fuel,  piston  seizure,  hot  bearings,  propeller  (on  marine) 
fouled,  low  compression, — 'always,  if  mechanical  defects  are  not  sus- 
pected, test  fuel  oil,  /and  if  the  fuel  is  up  to  standard  requirement  the 
engine  should  'be  stopped  and  again  throughly  examined. 


J10  QUESTIONS  AND  ANSWERS 

4.  What     Precaution     Should    be    Taken    With     Circulating    Water    and 
Spray  Air  System? 

'Strainers  should  be  kept  clean.  All  valves  kept  in  good  repairs. 
All  leaks  should  be  stopped  immediately  after  they  are  located. 

5.  What  Causes  Non-circulating  of  Water  Through   Engine?  How  Detect? 

How  overcome? 

Air  pockets  in  water-space  or  foreign  matter  blocking  up  pass- 
ages. If  there  'are  air-pockets,  they  can  be  ^detected  by  hot  spots  in 
cylinders.  Usually  the  air-pockets  shift  from  space  to  space  and  can 
be  eliminated  by  opening  air-cocks  on  cylinders. 

6.  What    May    Cause    the   Air  Compressor   to    Furnish    Insufficient   Air? 
How    is   it    Indicated?    How   Locate   Trouble?   What  to    Do? 

Leaky  valves,  leaky  rings,  too  much  clearance  on  top  of  pistons. 
If  suction  valves  are  leaking,  the  suction  line  will  heat  and  gauge  pres- 
sure on  proceeding  stage  will  run  high.  If  discharge  valves  are  leaking, 
gauge  pressure  on  proceeding  stage  will  run  low.  Leaky  rings  will 
cause  the  first  stage  to  build  up;  if  it  is  the  second  or  third  stage,  or  if 
the  first  stage,  air  will  blow  into  crank  case. 

If  volume  clearance  is  too  -much,  all  pressure  will  run  high 
except  the  third  stage.  If  valves  are  leaking,  they  must  be  re-ground. 
If  rings  are  leaking,  they  must  be  re-newed.  If  clearance  is  too  great 
piston  must  be  raised. 

7.  What  Causes  Cylinder  and  Cylinder-heads  to  Crack?  How  to  Detect? 

One  of  the  principal  causes  is  over-heating.  In  the  case  one 
cracked,  it  will  be  observed  by  lack  of  firing,  causing  stopping.  To 
detect,  shut  off  ifuel  and  open  try-cock,  when  water  will  be  noticed 
flooding  cylinder. 

8.  If   No.    5    Cylinder    Head    is   Cracked    so    that    the    Circulating    Water 
Runs    into  the   Cylinder;    r.    is    Important   that   the    Engine    Continue 
Running.      What    to    Do. 

Cut  a  strip  of  tin  that  is  wide  enough  to  cover  water  port  in 
the  head  and  narrow  enough  to  pass  between  the  studs  that  secures 
the  flange  to  the  head.  Loosen  off  nuts  on  studs  and  force  the  tin  be- 
tween the  flange  and  the  gasket,  leaving  the  'gasket  between  the  tin 
and  -the  flange  on  the  connection  to  the  header.  Secure  the  nuts  and 
close  off  the  valve  that  connects  water  line  to  the  bottom  of  that  cylind- 
er. Free  inside  of  cylinder  of  water.  Drain  water  out  of  the  head. 
Cut  out  that  cylinder,  so  that  it  cannot  fire  and  run  again. 

9.  The    Exhaust    Rocker   Arm    Breaks   On    No.   7   Cylinder   of   Starboard 
Engine,     (when    twin)     there    are    no    Spare     Rocker    Arms    Aboard. 
What  to   Do,  to   Keep   Engine    Running. 

Remove  broken  parts.  Take  the  intake  rocker  arm  and  put  it  in 
place  of  broken  rocker.  The  intake  valve  will  open  with  the  suction 
created  by  the  piston  on  its  suction  stroke.  If  the  valve  spring  is  too 


QUESTIONS  AND  ANSWERS  111 

strong,  same  may  be  ground  off  of  each  end.     This  cylinder  will  not  get 
enough   air  for  full   power   but   will  do  very   well   for  normal   running. 

10.     How  Would  You  Adjust  the  Compression  on  the  Working  Cylinders? 

First,  take  compression  cards  on  all  working  cylinders;  which 
is  done  in  'following  manner: 

Connect  Indicator  gear  to  the  cylinder.  Start  circulating  pump. 
Build  up  pressure. 

Turn  the  engine  over  (with  motor,  when  equipped  with  same)  and 
build  up  speed  to  about  normal  running  speed.  Then  open  the  cock 
allowing  the  pencil  of  indicator  -to  make  <four  or  five  strokes  on  the 
card.  Then  close  off  cock  and  shut  down  the  engine.  Take  a  card 
in  this  way  on  each  cylinder  of  engine.  When  taking  cards  the  fol- 
lowing should  be  noted:  There  should  be  no  valve  leaks.  Roller  clear- 
ances should  be  adjusted  and  then  the  engines  should  be  run  at  the 
same  speed  for  each  cylinder  when  taking  cards. 

After  cards  are  taken,  the  cards  must  be  carefully  (measured  to 
find  out  how  much  compression  there  is  in  each  cylinder ;  then  the 
compression  can  be  raised  or  lowered  as  the  case  may  require  in  the 
following  manner: 

Jack  the  engine  over,  so  piston  reaches  top  center  of  cylinder 
to  be  worked  first.  Remove  the  nuts  from  the  crank  pin  'bolts,  leaving 
bolts  and  brasses  in  place  .  The  bolts  can  be  locked  in  place.  Put  pin 
through  bottom  cylinder  wall  beneath  the  piston  to  take  the  weight 
of  piston. 

Again  jack  the  engine  slowly  by  hand  until  crank  has  traveled 
far  enough  on  its  own  down  stroke,  to  allow  the  piston  to  come  down  on 
the  pin  through  the  cylinder.  The  pin  will  hold  the  piston  and  allow 
the  crank  brass  to  leave  the  connecting  rod.  When  doing  this,  the 
crank  pin  bolts  must  be  carefully  watched,  so  that  they  will  not  catch 
in  the  holes  in  the  foot  of  the  rod.  After  the  brass  is  far  enough  from, 
the  rod,  the  compressor  liners  can  be  attended  to  also;  minimizing  or 
adding  as  the  case  may  require. 

After  the  right  amount  of  liners  are  between  the  top  of  the 
brass  and  bottom  of  the  rod,  jack  the  engine  back  to  top,  secure  the 
bearing  and  remove  the  pin  which  is  through  the  bottom  of  the  cylindei 

When  working  on  the  cylinder  is  completed,  compression  must 
be  taken  again  and  cards  measured  as  before.  Each  cylinder  should 
have  very  near  the  same  compression,  which  is  usually  about  480 
pounds  per  square  inch,  although  cylinders  will  fire  with  much  less 
compression. 

It  is  advisable,  to  not  allow  over  10  pounds  difference  between 
the  highest  and  lowest  compression  to  exist. 

When  adjusting  compression  after  installing  a  new  piston  or 
new  rings,  on  one  piston  it  should  be  set  about  10  pounds  lower  than 
the  other  cylinders,  because  as  the  rings  wearing  in,  the  compression 


112  QUESTIONS  AND  ANSWERS 

will  increase  until  the  rings  are  worn  smooth,  then  compression  should 
be  readjusted.     It  will  usually  be  found  too  high. 

11.  How  is  the  Governor  Adjusted? 

Usually  on  Diesel  governors,  the  place  where  the  governor  cuts 
oft'  the  fuel,  is  controlled  by  the  tension  on  the  top  spring  in  the 
governor.  The  tension  of  the  spring  is  regulated  by  a  threaded 
bushing  at  the  lower  end  of  the  spring.  The  bushing  is  secured  with  a 
lock  nut.  The  greater  the  tension  on  the  spring  the  greater  speed  the 
engine  will  reach  before  governor  cuts  off  the  fuel.  The  adjusting 
bushing  is  screwed  in  a  certain  distance,  thereby  bringing  a  certain 
tension  to  ibear  on  the  spring. 

'The  engine  is  then  run  to  ascertain  where  the  governor  cuts 
off  the  fuel.  The  tension  may  then  be  properly  regulated  according 
to  the  required  revolution.  The  lower  spring  only  takes  up  all  lost 
motion,  keeping  the  stem  from  oscillating. 

12.  If   Engine   Should    Lose   Compression,   Where   Would   You    Find   the. 
Trouble? 

(1)  Sticky  inlet  valve;  (2)  Fitted  or  corroded  exhaust  valve; 
(3)  Improper  seating  of  either  valve;  (4)  A  loose  or  open  compression 
tap;  (5)  Defected  piston  rings;  (6)  Leaky  gaskets;  (7)  Lack  of  lubri- 
cation around  cylinder  walls,  etc. 

13.  How  Would   You    Detect  a   Leaky   Spray   Valve? 

There  will  .be  a  loud  thump  in  the  cylinder,  caused  by  premature 
firing. 

14.  How  Would  You   Detect  a   Leaky  Fuel  Check? 

Cylinder  will  fire  light  and  some  times  miss,  especially  when 
running  slow  or  when  carrying  high  spray  air.  To  test:  Open  fuel  by- 
pass. If  air  blows  through  the  drain  line,  it  is  a  sure  sign  of  leaky 
check. 

15.  How  Would  You  Detect  Too  Low  Spray  Pressure? 

iSpray  valve  will  heat;  caused  by  fuel  burning  in  the  valve  body. 
(This  is  liable  to  cause  sticking  of  valve)  If  the  spray  pressure  is  high 
enough  to  prevent  oil  burning  before  it  enters  the  cylinder  and  jet 
not  high  enough  to  give  a  proper  mixture,  there  will  be  black  exhaust, 
caused  by  incomplete  combustion. 

16.  How  Would  You  Detect  Excessive   Lubrication? 

White  smoke,  often  is  caused  by  too  much  lubricating  oil  burning 
in  the  cylinder. 

17.  How  Would  You   Detect  Improper  Combustion? 
Black  smoke  denote  improper  combustion. 

18.  How  Would  You  Detect  a  Leaky  Exhaust  Valve? 

A  leaky  exhaust  valve  will  usually  heat  up  and  sometimes  stick. 
The  temperature  of  the  exhaust  gases  will  be  too  high. 


QUESTIONS  AND  ANSWERS  113 

19.  How    Would    You    Detect   One    Cylinder    Missing? 

The  engine  will  slow  down,  and  if  floating  the  motor,  (where  motors 
are  in  use  for  starting  purpose)  the  Ampere-meter  will  register 
an  irregular  load,  and  by  opening  try  cocks. 

20.  How  Would  You  Detect  Too  Low  Compression? 

Cylinders  are  liable  to  miss,  especially  if  running  slow.  Use 
indicator  and  take  compression  card  by  cutting  off  spray  air  and  opening 
on  fuel,  so  there  will  be  no  expansion  and  no  raise  in  pressure  caused 
by  injection  air. 

21.  How  Would1  You   Detect  Leaky  Air  Cooler? 

The  discharge  pipe  from  cooler  to  next  stage  suction  will  heat  up; 
caused  by  air  blowing  the  water  from  around  the  coil.  This  will  fre- 
quently happen,  if  the  next  stage  suction  is  leaking,  but  if  the  valve  is 
leaking,  the  end  of  the  pipe  next  to  compressor  will  be  hottest.  The 
gauges  wlill  also  show  if  the  valve  is  leaking. 

22.  How  Would  You  Discover  if  the  Third  Stage  Coil  Is  Leaking? 

If  the  third  stage  coil  is  leaking,  the  spray  air  line  will  heat  up 
and  very  often  the  entire  engine  \will  heat  or  the  cylinder  next  to  the 
leaky  coil;  or  if  the  engine  has  a  relief  valve  on  the  circulating  water 
it  may  raise. 

23.  How  Would    You    Detect  a    Leaky   Oil   Cooler? 

This  can  be  discovered,  if  the  water  pressure  is  greater  than  the 
oil  pressure,  accomvanied  by  filling  up  sump  tank,  and  if  tested  with 
nytrate  of  silver  it  will  show  wsalt.  If  the  oil  pressure  carried  is  greater 
than  the  water  pressure,  the  pump  will  run  down  too  fast  with  a  conse- 
quential greasy  circulating  water  discharge. 

24.  How  Would  You   Detect  a   Leaky  Air  Starting  Valve? 

This  can  be  discovered  by  extreme  heating  of  pipe  leading  to 
wards  starter. 

25.  How  Would  You  Detect  a  Sticky  Spray  Valve? 

iSticky  spray  valves  will  cause  a  loud  thump  in  the  cylinder  and 
sometimes  raise  the  cylinder  relief  valve. 

26.  How  Would   You   Detect  Cam    Rollers  Being   Heated? 

This  may  toe  caused  by  the  exipansion  of  valve  stem,  causing  the 
roller  to  be  in  contact  with  the  cam  all  the  time.  They  may  also  hold 
the  valve  off  its  seat. 

27.  If   the    Third    Stage    Air   Compressor    Discharge    Valve    was    Acting 
Slow,  Where  Would  You   Find  the  Cause? 

This  may  be  caused  by  broken  spring  or  carbon  on  valve.  Thi.s 
will  cause  the  second  stage  (pressure  to  run  too  high. 


114  QUESTIONS  AND  ANSWERS 

28.  What  Causes  Heating  of  Clutch  Collar? 

This  is  due  to  spider  not  being  pulled  past  center  of  the  shoes.  The 
collar  should  run  free  at  all  times. 

29.  What  Causes  Slipping  of  Clutch? 

This  is  indicated  by  engine  racing,  also  the  clutch  band  on  the 
fly  wheel  will  heat  up. 

30.  If  Repeated  Breakage  of  Crankshaft  Should  Occur,  How  Would  You 
Account  For  It? 

Repeated  breakage  of  crank  shaft  of  Diesel  engine  is  likely 
*due  to  unequal  working  in  cylinders,  causing  shocks  and  undue  impacts. 
A  crank  shaft  usually  breaks  after  the  material  has  become  crystallized, 
and  when  a  break  has  occurred  it  may  toe  "taken  for  granted,  that  more 
or  less  crystallization  has  taken  place  throughout  the  whole  crank  shaft 
material.  The  original  can  be  nearly  recovered  by  heat  treatment,  and 
the  whole  crankshaft  should  be  so  treated  occasionally,  at  least  when 
ever  part  is  repaired  by  welding. 

31.  What  Effect  Has  An  Undue  Amount  of  Water  in  Fuel  Oil  of  Engine? 
Water  lowers  the  heating  value  of  the  oil,  as  its  evaporation  con- 
sumes fuel;  it  also  lowers  the  temperatures  of  the  combustion  space.    A 
purchaser  should  not  pay  for  water  and  the  cost  of  transporting  it  when 
lie  is  buying  oil.     Fuel  oil  should  not  carry  more  than  0.5  per  cent  of 
water.      Mechanically    entrained    water,    which    will    separate    from    the 
oil  and  accumulate  in  the  bottom  of  thei  fuel  tank,  will  cause  failure  of 
ignition,  and  if  it  displaces  the  oil  in  the  fuel  valves  long  enough,  the 
engine  will  stop. 

32.  What  is  the  Burning  Point  of  Oil? 

The  "'Burning  Point"  of  an  oil  is  the  temperature  at  which  it  ignites 
and  continues  to  iburn  in  an  open  cup.  The  burning  point  is  no  criterion 
of  the  usefulness  of  an  oil  for  use  in  Diesel  engine,  save  that  it  is  a 
further  index  of  the  fire  hazard.  The  nearer  the  burning  point  to  the 
flash  point,  if  the  flash  point  is  low,  the  greater  is  the  fire  hazard. 
A  low  flash  point  and  a  high  burning  point  indicate  the  presence  of  high 
volatile  oils  mixed  with  heavy  oils.  The  burning  point  is  10  degree 
to  50  degree  C.  and  rarely  100  degree  C.  higher  than  the  flash  point. 
Extreme  differences  usually  indicate  crude  oils  that  have  not  been 
"topped,"  or  mixtures  of  volatile  and  heavy  residual  oils.  If  the  flash 
point  is  sufficiently  high  to  preclude  fire  hazards,  determination  of 
the  (burning  point  is  superfluous. 

33.  What  Effect  Will  "Ash"  Deposites  of  Fuel  Oil  Have  on  the  Engine? 

Ash  is  the  most  detrimental  remnant  of  the  burning  of  fuel  oils 
for  Diesel  engines,  as  it  causes  excessive  wear  of  cylinders  and  exhaust 
valves.  The  ash  is  usually  composed  of  mineral  particles  of  great 
hardness,  such  as  quartz  and  sillicates,  or  oxides  or  iron  aluminum, 
which,  becoming  mixed  with  the  film  or  lubricating  oils,  adhere  to  the 


QUESTIONS  AND  ANSWERS  115 

piston  and  cylinder  walls,  accumulate,  and  causes  excessive  wear.  An 
ash  content  in  excess  of  0.05  per  cent  will  render  an  otherwise  ex- 
cellent fuel  unsuitable  for  use  in  a  Diesel  engine. 

34.  What  Importance  Has  Parafine  Content  in  Fuel  Oil? 

The  parafme  content  of  an  oil  is  important  merely  in  its  physical 
effect  on  the  oil.  Oil  with  an  appreciable  parafme  content  may  soli- 
dify or  become  highly  viscous  at  low  temperatures  (0  degree  to  15  de- 
gree C.)  Moderate  heating  of  oils  will  obviate  any  difficulty  from 
the  sluggishness  at  low  temperature  due  to  parafine  content. 

35.  What  Effect  Has  "Asphalt"  Content  in  Fuel  Oil  on  Diesel   Engines? 

High  asphalt  content  points  to  high  content  of  constituents  that  will 
produce  a  coke  residue.  If  the  coke  residue  of  an  oil  is  satisfactory,  its 
asiphalt  content  may  be  disregarded  as  being  of  no  importance.  High 
asphaltum  content  makes  an  oil  objectionable  for  use  in  engines  with 
fuel-valves  that  are  closed  by  fuel  needles.  It  tends  to  gum  the  needle 
and  causes  it  to  stick.  By  heating  the  oil  sufficiently  to  make  it  more 
liquid,  this  objection  is  greatly  removed.  Such  oil  is  as  a  rule  highly 
viscous  and  they  have  to  be  heated  to  cause  the  necessary  fluidity. 

36.  If  Engines  Are  Running  and  Bilges  Are  Afire  What  Should  Be  Don'e? 
Stop  engines  immediately,  give  fire  alarm  and  shut  down  blowers  or 

any  other  machinery  that  causes  circulating  of  air. 

Start  fighting  fire  with  apparatus  with  which  boat  is  provided.  If  fire 
has  started  from  electrical  appliances,  all  switches  must  be  pulled.  If  fire 
cannot  be  stopped  any  other  way,  it  may  be  smothered  by  getting  all 
hands  out  of  the  engine  room  and  close  water-tight  doors  and  prevent  all 
fresh  air  from  entering  engine  room. 


MACHINERY  MATERIAL 
1.     Define  the  Meaning  of  Strain: 

Whenever  a  force  is  applied  to  any  member  of  a  machine  or  structure 
the  shape  is  altered.  The  change  in  any  linear  dimension  is  called  the 
strain  and  the  change  per  unit  of  linear  dimension  is  called  the  unit 
strain. 

2      Define  Stress: 

If  a  machine  part  is  acted  on  by  forces,  there  exists  a  tendency 
within  a  body  to  resist  the  external  force  to  tear  apart  or  to  crush  the 
body.  The  unit  stresses  and  unit  strains  correspond  respectively  to  loads 
applied  to  machine. 

3.     Ultimate  Strength: 

In  tension  tests  of  machine  material  there  is  usually  a  corresponding 
figure  dealing  with  defined  load  of  maximum  proportion  before  rupture 


116  QUESTIONS  AND  ANSWERS 

should  occur.     The  unit  stress  corresponding  to  this  load  is  called  the 
ultimate  strength,  or,  more  briefly,  the  ultimate  for  the  material. 

4.  What  Are  the  Principal  Ingredients  in  Steel? 

Carbon  and  iron  are  the  principal  ingredients  in  steel,  but  special 
steels  of  great  strengths  and  toughness  are  made  by  alloying  carbon  and 
iron  with  other  elements.  Commonly  alloy  steels  are:  Nickel  steel, 
Tungsten  steel,  Vanadium  steel  and  Manganese  steel. 

5.  Name  the  Uses  for  Following  Metals  on  Machinery: 

(a)  Lead,  Tin,  Zinc:    These  metals  are  used  in  special  cases  in  which 
strength  is  not  requisite,  and  in  which  resistance  to  chemical  action  is 
necessary.    They  are  used  in  alloys  for  bearings  on  machinery. 

(b)  Brass:    This  is  an  alloy  for  zinc  and  copper.    It  is  used  for  small 
machine  parts,  in  which  resistance  to  corrosion  is  of  importance.     It  is 
also  used  as  a  bearing  metal. 

(c)  Bronze:    This  is  an  alloy  of  copper  and  tin.     It  is  used   where 
resistance  to  corrosion  is  necessary,  and  where  strength  is  also  required. 
It  is  used  as  a  bearing  metal  in  the  highest  grade  of  bearings.    It  is  very 
expensive  as  compared  with  other  metals  of  similar  use. 

6     What    is   the    Approximate   Composition    of    Babbit    Metal? 

The  approrimate  composition  of  babbitt  is  tin,  89  parts  copper,  4 
parts;  antimony,  7  parts. 

7.  What  materials  Are   Machine   Frames   Made  Of? 

For  engines,  where  little  vibration  exists,  cast  iron  is  the  material 
generally  used  on  account  of  its  low  cost. 

8.  What  Material  Is  Used  for  the  Manufacture  of  Cylinders? 

Cylinders  are  almost  exclusively  made  of  cast  iron,  while  in  lighter 
machines  aluminum  is  used  in  particular  for  high  speed  engines.  Usually 
the  thickness  is  determined  not  by  consideration  of  strength,  but  by  com- 
sideration  of  foundry  practice.  It  is  impossible  to  cast  a  very  thin  cyl- 
inder. Cast  iron  makes  a  much  better  bearing  metal  for  the  rubbing  of 
the  piston  than  does  steel. 

9.  What  Material    Is  Used  for  the  Manufacture  of  Shafting? 

•Cold  rolled  steel  is  very  widely  used  on  account  of  the  ease  and 
cheapness  with  which  it  can  be  rolled  true  to  shape  and  size. 

10.  Where  Is  Nickel  Steel  Preferable  to  Common  Steel? 

Nickel  steel  is  widely  used  where  high  strength  is  necessary,  as  on 
valves  on  Internal  Combustion  Engines.  A  Nickel  content  of  3.5  per  cent 
makes  steel  stronger  and  resistant  to  shocks.  Nickel  strengthens  steel 
without  reducing  its  ductillity  to  any  great  ertent,  hence  Nickel  steel 
is  tough. 

11.  What  Effect  Has  the  Adding  of  Vanadium  to  Steel? 

Vanadium  in  the  form  of  ferrovanadium  adds  great  strength  to  steel, 


QUESTIONS  AND  ANSWERS  117 

and  seems  to  be  especially  valuable  in  adding  resisting  power  against  re- 
peated application  of  stress.  Vanadium  seems  to  benefit  cast  iron,  prob- 
ably on  account  of  its  tendency  to  remove  oxygen  from  the  iron. 

12.  What  Effect  Has  the  Adding  of  Tungsten  and   Molybdenum  in  Steel? 
The  presence  of  Tungsten  and  Molybdenum    in    steel  so  affects  the 

critical  temperature,  at  which  steel  changes  from  a  very  hard  material 
to  a  much  softer  material,  that  with  proper  heat  treatment  Tungsten  and 
Molybednum  steels  retain  their  hardness  at  a  red  heat. 

13.  What  Effect  Will  Titanium   Have  on  Steel? 

Titanium  is  used  as  an  ingredient  for  steel,  and  renders  the  steel 
more  uniform  in  quality  throughout. 

14.  What   Effect  Will   Manganese  Have  on  Steel? 

A  Manganese  content  of  greater  than  7  per  cent  makes  steel  very 
strong  and  tough,  but  so  hard  -as  to  be  practically  unworkable.  Man- 
ganese steel  usually  contains  about  12  per  cent  of  Manganese,  and  while 
by  the  exercise  of  great  care  it  may  be  forged  or  rolled,  it  is  usually  cast 
directly  into  the  desired  shape  of  the  finished  product. 

15.  What   Effect   Will   Chromium    Have  on   Steel? 

Chromium  makes  possible  a  steel  of  great  hardness  and  strength. 
Very  often  it  is  used  in  connection  with  nickel  in  making  special  grades 
of  steel. 

16.  What  Effect  Will  Copper  Have  on  Steel? 

The  adding  of  about  1  per  cent  of  copper  has  no  marked  effect  on 
the  strength  or  ductility  of  steel,  but  greatly  diminishes  the  tendency 
to  corrosion. 

17.  What  Effect  Will  Silicon   Have  on  Steel? 

A  Silicon  content  of  about  4  per  cent  increases  the  magnetic  perme- 
ability of  steel  and  also  its  electrical  resistance.  This  combination  maikes 
an  excellent  steel  for  the  magnetic  circuits  of  electrical  machinery.  Sili- 
con always  tends  to  give  steel  an  acid  reaction,  and  hence  a  low  Silicon 
content  is  always  found  in  basic  steel. 

18.  What  Effect  Will  Carbon   Have  on  Ste-el? 

Carbon  up  to  1.25  per  cent  increases  the  strength  of  iron,  and  the 
increase  is  approximately  proportional  to  the  carbon  content. 

19.  What  Is  Semi-Steel? 

The  melting  of  20  to  50  per  cent  of  steel  scrap  with  pig  iron  pro- 
duces semi-steel.  The  product  is  a  cast  iron  of  high  strength  and  low 
carbon  content;  it  is  not  steel.  In  the  manufacture  of  iron  castings  in 
which  strength  is  important,  Semi-Steel  is  used.  ' 


CHAPTER  VII. 


FUEL   FEED  AND   IGNITION 

There  is  no  doubt  that  maximum  fuel  economy  is  attained  in  a  Diesel 
engine  at  a  certain  load  when  air  and  fuel  are  used  in  a  certain  propor- 
tion. But  this  point  may  be  prevented  by  overheating,  pounding,  car- 
bonization, or  undue  strain  on  the  machinery.  Engines  designed  for 
high  compression  are  also  designed  for  considerable  excess  of  air  at 
rated  full  load.  Reducing  this  excess  by  injecting  more  fuel  might  shock 
certain  mechanical  parts  beyond  endurance.  Too  much  air  rt-sults  in  a 
lower  temperature  of  ignition  and,  apparently,  a  slower  rate  of  burning. 
Either  conditions  lowers  efficiency  for  reasons  pointed  out  in  following 
lines,  considering  basic  principles  of  Diesels. 

The  theoretical  thermal  efficiency  of  an  internal  combustion  engine  is 
given  by  .the  expression  (To  —  TI)  =  To. 

To  is  the  absolute  temperature  at  the  beginning  of  the  working  stroke 
and  TI  is  the  absolute  temperature  at  the  end  of  the  same  stroke.  Abso- 
lute zero  is  461  degrees  below  zero  on  the  Fahrenheit  scale.  A  tempera- 
ture of  70°  F.,  for  instance,  means  531°  referred  to  absolute  zero.  From 
the  above  efficiency  formula  it  is  evident  that  a  high  temperature  of 
combustion  at  dead  center  and  expansion  to  low  temperature  are  the 
theoretical  as  well  as  some  of  the  practical  requisites  of  fuel  economy. 
High  temperature  at,  dead  center  is  secured  by  high  compression  in  a 
small  clearance  space  and  by  complete  combustion  of  just  the  right  fuel 
proportion  before  the  piston  has  begun  the  working  stroke.  If  only  part 
of  the  normal  charge  is  compressed  in  a  fixed  clearance,  or  if  the  excess 
of  air  is  too  great,  or  if  combustion  continues  during  the  working  stroke, 
maximum  efficiency  cannot  be  obtained.  No  one  engine  in  practical 
operation  overcomes  all  these  "ifs"  under  light  load  condition. 

One  theoretical  way  of  securing  the  ideal  condition  would  be  (1) 
to  vary  the  quantity  of  mixture  containing  constant  proportions  of  fuel 
and  air,  and  (2)  to  vary  the  clearance  volume  in  accordance  with  the 
quantity  of  fuel  mixture  so  as  to  maintain  the  same  degree  of  com- 
pression at  all  loads.  The  first  requirement  is  practically  reached  by 
the  carburetion  engine,  but  a  fixed  unvariable  clearance  volume  exists  in 
all  types  of  engines  treated  herein.  'Consequently  the  carburetion  charge 
does*  not  receive  maximum  compression  during  light  load.  Since  the 
air  intake  is  not  throttled  down  in  semi-Diesel  and  Diesel  cylinders 
at  light  loads,  compression  remains  more  nearly  constant.  But  the 
proportion  of  fuel  is  cut  down  and  combustion  is  supposed  to  be  slower, 
both  of  which  conditions  reduce  the  maximum  temperature.  In  one 


FUEL  FEED  AND  IGNITION  119 

respect  the  Diesel  cycle  is  a  cross  between  carburetion  and  semi-Diesel 
principles.  Compression  pressure  is  nearly  constant  as  in  the  semi- 
Diesel  cylinder  but  the  total  supply  of  air  can  be  partly  reduced  with 
less  fuel  at  light  load  (as  in  the  carburetion  cylinder)  by  governing  the 
supply  of  injected  air  through  hand  regulation  of  compressor  valves. 

Prolongation  of  Diesel  fuel  injection  avoids  abortive  pressures  but 
prevents  full  utilization  of  heat  from  the  beginning  of  the  working 
stroke.  Injection  of  water  with  fuel  has  a  similar  effect  in  other  engines. 

One  valuable  but  only  partial  compensation,  in  the  case  of  low 
compression  in  any  type  of  engine,  is  the  fact  that  a  greater  degree  of 
expansion  is  secured  at  light  load.  Theoretically,  appreciable  fuel  econ- 
omy would  be  added  toy  increasing  the  ratio  of  expansion  beyond  that 
existing  in  practical  engines.  A  longer  stroke  relative  to  clearance 
would  be  necessary.  The  atmospheric  volume  of  air  would  then  have 
to  be  reduced  for  the  beginning  of  compression  to  avoid  injurious  pressure 
at  the  end  of  this  stroke.  Design  of  expansion  in  practical  machines 
is  a  compromise  between  fuel  economy  on  one  hand  and  commercial 
and  mechanical  limitations  on  the  other  hand.  In  general,  the  higher 
the  compression  in  a  given  type,  the  lower  is  the  ratio  of  expansion 
required  to  attain  equal  efficiency. 

In  the  case  of  the  semi-Diesel  engine  the  supply  of  air  for  each 
working  stroke  at  different  loads  remains  nearly  the  same.  This 
means  a  great  excess  of  air  at  light  load  when  the  fuel  supply  is 
cut  down.  Compression  pressure  remains  about  the  same,  but  explosion 
temperature  is  reduced.  Because  of  the  short  time  available  for  the 
fuel  and  air  to  mix  in  this  type,  it  is  probable  that  a  larger  excess 
of  air  is  required.  Also  an  efficient  device  is  necessary  to  divide 
the  oil  into  fine  particles,  especially  when  a  heavy  grade  is  burned. 
If  the  oil  is  not  properly  divided  and  distributed,  it  is  liable  to  "crack" 
or  decompose  into  parts  from  hydro-carbon  gases  down  to  pure  carbon. 
This  latter  is  the  cause  of  much  grief.  In  most  semi-Diesel  engines, 
oil  is  forced  through  one  or  more  fine  openings  in  the  fuel  nozzle. 
Its  mechanical  motion  in  contact  with  the  hot  ignitor  surface  help  to 
mix  it  with  the  air.  Some  combustion  chambers  have  practically  no  ob- 
struction of  openings  into  the  cylinder.  As  will  'be  seen  in  the  article 
on  the  Fairbanks-Morse  "Y"  engine,  which  uses  no  injection  water, 
represents  the  other  extreme.  Oil  is  injected  against  a  hot  tube  fixed 
inside  a  spherical  chamber.  The  bulb  connects  with  the  cylinder  through 
a  round  opening. 

Oil  is  broken  up  mechanically,  in  the  Diesel  cylinder,  by  the  com- 
pressed air  which  accompanies  it  past  the  nose  of  the  fuel  needle. 
Excess  of  air  is  governed  partly  toy  its  supply  pressure,  which  in  turn 
iL  controlled  by  hand  valves  on  the  compressor.  The  excess  runs  some- 
what the  same  as  with  semi-Diesel  operation.  Combustion  takes  place 
directly  behind  the  piston,  but  does  not  result  in  so  sudden  an  explo- 
sion and  shock,  on  account  of  the  gradual  admittance  of  fuel.  The  high 


120  FUEL  FEED  AND  IGNITION 

heat  of  compression  effects  positive  ignition  upon  comparatively  heavy 
oils. 

Generally  speaking,  the  higher  the  degree  of  compression  just  be- 
fore ignition  the  greater  is  the  efficiency.  This  is  an  example  of  the 
law  applied  to  heat  engines  which  states  that  the  per  cent  of  heat 
converted  into  work  varies  with  the  range  in  temperature  during  ex- 
pansion. High  compression  in  a  small  clearance  volume  results  in  a  high 
temperature  and  pressure  during  combustion  becoming  available  during 
expansion  to  lower  temperatures  and  pressures. 

Semi-Diesel  and  Diesel  engines  are  allowed  higher  compression 
because  fuel  is  not  admitted  until  the  piston  is  ready  for  the  combustion 
impulse.  Diesel  type  engines  are  of  course  built  to  withstand  the  high- 
est pressures  of  all.  Fuel  is  introduced  by  a  further  supply  of  com- 
pressed air  during  the  first  part  of  the  working  stroke,  an  arrangement 
which  allows  more  gradual  combustion  instead  of  instantaneous  ex- 
plosion. The  average  period  of  time  opening  of  the  fuel  valve  may  be 
considered  from  12%  to  15%  of  the  stroke. 

Experiments  in  efficiency  tests  of  Diesels  have  proven,  that  the 
conversion  of  energy  is  well  near  to  35 '/  from  the  fuel  into  outside 
mechanical  work.  From  this  maximum  with  various  engines  and  loads, 
the  'percentage  ranges  down  to  zero,  in  which  latter  case  just  enough 
fuel  is  admitted  to  run  the  engine  without  load. 


FUEL    INJECTION    VALVES 

Of  the  numerous  mechanical  contrivances  and  different  accessor- 
ies necessary,  none  is  more  important  than  the  device  causing  the  fuel 
to  be  brought  in  direct  communication  with  the  existing  heat  in  the  cylin- 
der, caused  -by  compression,  than  the  Fuel  Injection  Valve. 

The  functions  the  fuel  injection  valve  has  to  perform  are  two-fold: 
In  the  first  place,  that  of  a  valve  to  introduce  the  fuel  oil  into  >the  cylin- 
der with  equal  regularity;  and  the  second,  that  of  a  sprayer,  to  divide 
the  fuel  into  minute  particles,  causing  a  "constant  volume." 

The  operation  of  this  valve  may  be  explained  in  following:  The 
valve  arrangement  is  formed  by  a  needle,  ending  in  a  cone,  held  accurate 
on  a  conical  seating  by  the  valve  spring.  A  lever  actuated  by  a  cam, 
raises  the  needle  at  the  required  moment,  establishing  communication 
between  the  fuel  injection  valve  casing  and  the  cylinder. 

The  spraying  is  effected  by  means  of  a  number  of  washers,  pro- 
vided with  small  holes,  and  by  a  cone  grooved  along  its  gentrating  lines, 
threaded  by  a  tube  usually  made  of  bronze.  In  placing  the  washers,  great 
care  should  be  taken  in  properly  "lining  of  holes  on  washers,"  the  same 
never  to  be  placed  hole  to  hole,  but  rather  so  that  the  hole  of  the  next 
following  washer  is  irregular  placed. 


FUEL  FEED  AND  IGNITION 


121 


The  washers  may  be  minimized  when  a  change  of  fuel  takes  place. 
That  applies  to  difference  in  gravities,  with  consequental  results  in 
lower  or  higher  viscosity,  as  the  case  may  be. 

A  small  hole,  running  through  the  center  of  the  steel  diaphragm 
directs  the  air,  assisting  the  action  of  the  valve  in  the  proper  distri- 
bution of  its  fuel. 


Demonstration   of   actuating   valves    through   cams 

Very  often,  the  clogging  of  the  channel  hole  in  the  check  valve 
causes  complication  and  when  taking  the  valve  apart,  the  trouble  may 
be  discovered. 

It  is  necessary  to  clean  interior  parts  of  fuel  injection  valve  from 
foreign  matters,  and  impurities  assembling  in  the  channel  must  be  elim- 
inated. 

The  oil  delivered  under  pressure  from  the  fuel  injection  pump,  is 
directed  into  the  fuel  injection  valve  just  above  the  perforated  washers, 
and  assisting  the  high  pressure  compressed  air  from  the  fuel  injection 
bottles  fills  the  sphere  around  the  sleeve.  At  the  moment  the  valve 
spindle  raises,  the  air  at  50  to  70  atmospheres — 700  to  1,000  pounds  per 
square  inch — rushes  into  the  cylinder,  in  which  the  pressure  is  now  30  to 
35  atmospheres — 430  to  500  pounds  per  square  inch — drawing  with  it  the 
fuel,  which,  in  passing  through  the  holes  of  the  washers,  is  divided  in  a 
fine  mist. 

The  fuel  oil  in  this  state  of  "fog"  enters  the  combustion  chamber, 
containing  the  heat  of  ignition,  to  use  the  expression,  at  the  end  of  the 
compression  strokes  it  spontaneously  ignites.  The  combustion  takes 
place  practically  at  constant  pressure  throughout  this  period  of  the 
stroke,  during  which  the  oil  continues  to  be  forced  into  the  cylinder. 

It  is   vital   that  the  valve   actuating  gear  in   functioning  its  lifting 


122 


FUEL  FEED  AND  IGNITION 


and  opening  of  valve  should  not  be  influenced  by  variation  of  load  of 
engine.  The  pressure  per  ratio  between  the  interior  of  the  fuel  injec- 
tion valve  casing  and  the  cylinder  should  remain  constant.  In  this 


Diagram  of  Valve  Settings  of  Crankshaft  on  Four-cycle  Engine 

way  no  variation  of  velocity  efflux  and  the  quantity  of  air  issued  with 
each  working  stroke  occurs,  immaterial  of  existing  horse  power  of  en- 
gine. 

While  the  supply  and  the  demand,  regulated,  corresponding  to  the 
load  capacity  of  the  engine,  is  taken  care  of  through  the  fuel  injec- 
tion pump  and  its  governor  arrangement,  it  is  seen  that  the  desired 
amount  of  fuel  necessary  to  keep  up  the  momentum  of  impulse  is  in  this 
way  properly  maintained. 

An  oil  injection  nozzle  used  on  the 
Giant  Oil  Engine  is  seen  in  the  illustra- 
tion. This  is  a  distinctly  exclusive  fea- 
ture patented  by  the  Chicago  Pneumatic 
Tool  Company. 

It  is  screwed  directly  into  the  center 
of  the  combustion  chamber  head.  It  con- 
tains a  ball  check  valve  and  is  a  novel 
departure  from  the  usual  spring  type  and 
numerous  similar  injection  nozzles  used, 
working  identical  in  working  operation. 

As  the  inspiration  and  compression 
strokes  are  common  to  all  types  of  en- 
gines and  the  method  of  injection  is  the 


Oil 


Injection    Nozzle    of 
Ball-Check     Type 


the 


FUEL  FEED  AND  IGNITION 


123 


main   feature   under   discussion,   a  detailed    description   of   the   injection 
and  combustion  period  will  be  gone  into. 

During  the  inspiration  stroke,  a  measured  quantity  of  fuel  is  de- 
livered near  the  bottom  of  the  fuel  injector  just  above  the  needle  valve 
on  engines  using  the  method  of  established  types  generally  used. 
The  injection  air,  which  in  all  cases  is  well  above  the  compression 
pressure,  is  forced  against  the  fuel,  atomizes  it  and  forces  it  into 
the  cylinder.  One  point  worthy  of  note  is  the  fact  that  the  action  of 
the  injection  air  thoroughly  atomizes  the  fuel  prior  to  injection,  and 
upon  this  atomization  depends  the  combustion  efficiency  of  the  cycle. 
The  amount  of  fuel,  as  before  stated,  is  regulated  >by  the  fuel  pump  and 
governor.  The  duration  of  the  injection  or  combustion  is  also  regulated 
according  to  the  load  on  the  engine.  For  light  loads  the  injection 
valve  remains  open  a  shorter  period  than  for  heavy  loads.  Aside  from 
the  advantage  of  thorough  atomization  there  is  one  great  objection  to  this 
method  of  injection,  namely  refrigeration  during  injection. 


Valve    Settings    of   Double-Port-Scavenging    Two-cycle   Engine 


As  the  compressor  pressure  is  about  500  pounds  and  the  injec- 
tion pressure  between  700  and  1000  pounds,  there  will  ibe  a  very  rapid 
expansion  of  the  injection  air  from  the  maximum  to  the  compression 
pressure.  This  rapid  expansion  causes  a  great  reduction  in  the  tempera- 
ture of  the  injection  air  and  fuel,  just  as  rapid  compression  causes 


124 


FUEL  FEED  AND  IGNITION 


an  increase  in  the  temperature.  The  effect  of  this  sudden  reduction  of 
temperature  causes  a  time  lag  in  the  combustion — because  cold  fuel  is 
difficult  to  ignite — as  well  as  the  collection  of  small  particles  of  fuel 
on  the  piston,  at  which  point  local  iburning  occurs.  The  result  of  this 
is  an  invariable  sag  of  the  piston  head  due  to  excessive  local  tempera- 
ture. Were  it  possible  to  use  highly  heated  air  for  injection,  this  re- 
frigeration would  to  a  great  extent  be  overcome.  However,  with  the 
Diesel  method  of  injection,  combustion  would  take  place  to  the  injection 
valve  prior  to  the  injection  period.  It  is  well  to  note,  that  in  the 
Diesel  engine  the  fuel  injection  is  in  mechanically  timed  relation  to 
the  piston  position,  'but  as  the  injection  and  compression  pressure  are 
always  constant,  the  rate  of  injection  is  also  constant. 

In  accompanying  illustration  a  Car- 
els  type  of  fuel  inlet  valve  is  shown. 
It  follows  the  principle  of  valves  used 
on  most  engines.  The  amount  of  oil 
desired  to  enter  is  automatically  re- 
gulated (by  the  action  of  the  governor 
on  the  pump,  depending  on  the  require- 
ment. 

In  accomplishing  the  pulverizing  the 
oil  is  forced  through  its  entire  passage 
into  the  spraying  arrangement,  con- 
sisting of  four  metal  rings  with  usual- 
ly about  20  holes  drilled  into  them  of 
the  size  of  1/10  to  1/16  of  an  inch  in 
diameter.  The  holes  in  the  washers, 
or  rings,  are  placed  in  staggering  po- 
sition to  accomplish  proper  spraying 
results.  Beneath  the  washers  is  a 
conical  shaped  piece,  acting  as  a 
guide  to  allow  the  oil  to  pass  into 
small  passage  ways,  in  similarity  to 
nozzles. 

It  enters  then  direct  into  the  cylin- 
der by  the  expanding  orifice,  made  of 
steel,  the  guides  of  the  needle  valve 
usually  cast  of  iron.  With  the  high 
pressure  of  the  injection  air,  in  the 
period  when  the  lifting  of  the  needle 

valve  takes  place,  the  fuel  is  forced  through  the  pulverizer  by  the  air 
in  minute  particles  of  fine  spray  into  the  combustion  chamber  where  it 
is  ignited  coming  in  contact  with  the  compression  temperature. 

Ignition  Failures:  There  are  numerous  causes  of  ignition  failures 
on  Diesels.  If,  when  attempting  to  start  the  engine,  ignition  fails  to 
occur,  it  may  be  attributed  to  one  or  more  of  the  following  causes:  Low 
Compression;  Cylinders  too  cold;  Insufficient  fuel;  Fuel  injection  too 
late;  failure  of  spray-air  supply.  If  the  engine  cannot  be  brought  in 


Carelfi   Type  of  Fuel  Inlet 

Valve    used    on    Norclbrry 

Diesels 


FUEL  FEED  AND  IGNITION 


125 


motion   after   repeated    attempt,    an    investigation    should   be    made   and 
causes  determined  and  the  same  be  remedied. 

The  compression  in  the  cylinders  should  in  first  place  be  given  due 
attention.  If  the  compression  is  not  sufficiently  high,  the  desired  tempera- 
ture necessary  to  ignite  the  oil  is  too  low.  In  many  instances  this  is 
due  to  leaky  cylinder  head  or  valve  cage  gaskets.  If  leaky  relief  valve, 
this  defect  will  be  noticeable  by  the  noise  of  escaping  air. 

Lack  of  sufficient  fuel  or  total  failure  of  supply  to  cylinder  may 
be  caused  by  an  empty  fuel  service  tank  or  through  stoppage  of  fuel 
in  the  fuel  line  between  measuring  pump  and  tank.  Examine  all  valves. 

On  some  types  of  fuel-measuring  pumps  the  air-starting  gear  and 
pump  mechanism  are  not  interlocked  in  such  a  way  that  the  pumps 
are  automatically  put  into  operation  when  the  engine  begins  to  turn 
by  air.  In  this  case  it  may  happen  that  the  pump  levers  are  not  properly 
brought  in  the  operating  position  before  starting. 


i 


Settings  of  Valve-Scavenging   Two-cycle  Engine 


Because  of  the  small  quantity  of  oil  handled  per  stroke  by  the  fuel 
measuring  pump  and  the  high  pressure  pumped  against,  this  pump 
is  very  sensitive  to  air  that  may  'be  present  in  oil.  A  fundamental 
requirement  in  good  pump  design  is  that  no  pockets  may  be  permitted 
in  the  oil  passages  in  pump  or  valve  chamber,  where  air  might  collect 
but  many  pumps  have  'been  and  are  still  toeing  built  that  do  contain  such 
pockets.  Most  pumps  are  provided  with  vent  valves  so  that  the  collected 


126  FUEL  PEED  AND  IGNITION 

air  may  be  blown  out.     Sometimes  the  fuel  may  be  prevented  from  reach- 
ing the  pump  by  an  air  pocket  in  the  pipe  between  the  pump  and  the  tank. 

A  very  common  cause  of  failure  of  fuel  supply  is  leakage  of  air 
past  the  check  valves.  In  all  closed  nozzle-type  spray  valves  the 
mixing  chamber  in  the  valve  body,  where  the  spray  air  and  oil  mix  be- 
fore entering  the  cylinder,  is  always  in  direct  communication  with  the 
spray-air  system  and  consequently  is  filled  with  air  at  injection  pres- 
sure. In  order  for  the  fuel  pump  to  force  the  oil  into  this  chamber 
against  the  air  pressure,  it  is  essential  that  the  oil  pipe  be  full  of  oil 
right  up  to  the  inlet  to  the  valve  chamber,  so  that  when  the  pump 
forces  a  small  amount  of  oil  into  the  pump  end  of  the  pipe,  an  equal 
amount  will  be  forced  out  of  the  other  end  into  the  valve  chamber. 

It  is  obvious  that  if  this  pipe  is  partly  filled  with  air,  the  oil  column, 
when  acted  upon  by  the  charge  of  oil  being  forced  into  the  pipe  by  the 
pump,  will  simply  compress  the  air  and  no  oil  will  be  discharged  into 
the  valve.  If  the  discharge  valve  of  the  fuel  pump  is  perfectly  tight, 
no  air  from  the  spray-valve  chamber  can  force  its  way  into  the  oil 
pipe  after  the  pipe  is  completely  filled  with  oil,  but  the  fine  grit  present 
in  nearly  all  fuel  oil  makes  it  very  difficult  to  keep  this  valve  perfectly 
tight  very  long.  For  this  reason  practically  all  Diesel  engine  builders 
install  a  check  valve  in  the  oil  line  to  each  spray  valve,  as  close  as 
possible  to  the  point  of  entry  of  oil  into  the  spray-valve  body.  This 
valve  closes  against  the  air  pressure  in  the  spray-valve  body  so  that 
the  oil  column  in  the  pipe  is  subjected  to  pressure  only  during  the  time 
the  pump  is  discharging  into  the  line  at  one  end  and  forcing  the  oil 
through  the  check-valve  at  the  other.  With  this  arrangement  a  pump 
will  work  quite  satisfactorily  even  though  the  discharge  valve  is  not 
perfectly  tight,  as  long  as  the  check-valve  remains  tight. 

The  spray-valve  should  be  tested  occasionally.  This  valve  can  be 
tested  while  the  engine  is  stopped,  by  turning  spray  air  from  the  bot- 
tles into  the  air  line  to  the  spray  valve  and  then  opening  the  by-pass  in 
the  fuel-oil  line  near  the  check  valve.  If  the  valve  leaks,  the  air  will 
blow  out  of  the  by-pass.  If  there  is  no  by-pass  in  the  line,  the  oil 
pipe  may  be  disconnected  at  the  pump  and  the  air  will  blow  out  there. 

Before  making  this  test,  the  engine  must  be  jacked  around  until 
the  spray  valve,  to  which  is  attached  the  line  being  tested,  is  in  the 
closed  position,  so  that  the  spray  air  will  not  iblow  into  the  cylinder. 
In  order  to  provide  additional  insurance  against  spray  air  leakage  into 
the  fuel  lines,  some  builders  provide  two  check  valves  in  each  oil  line 
and  two  discharge  valves  in  each  pump. 

Leaky  suction  valves  in  the  fuel  pumps,  or  valves  stuck  open, 
may  be  responsible  for  the  failure  of  the  oil  to  reach  the  cylinders. 
Examination  of  the  valve  and  seats  will  usually  indicate  a  leaky  condi- 
tion. 

When  the  fuel  contains  considerable  water,  the  water  may  settle 
to  the  bottom  of  the  supply  tank,  while  the  engine  is  stopped,  in  suffi- 


FUEL  FEED  AND  IGNITION  127 

cient  quantity  to  fill  the  pump,  so  that  water  instead  of  oil  will  be  in- 
jected into  the  cylinders.  The  obvious  remedy  for  this  is  to  drain  all  the 
water  out  of  the  system  before  attempting  to  start  the  engine. 

If  the  fuel  is  not  injected  into  the  cylinders  until  after  the  com- 
pressed air  has  started  re-expanding  as  the  pistons  move  away  from  the 
heads  and  increase  the  cylinder  volume,  the  temperature  of  the  air 
may  have  fallen  so  low  that  it  will  not  ignite  the  oil,  and  the  effect 
produced  is  the  same  as  in  the  case  of  low  compression.  This  late 
injection  may  be  caused  by  the  adjustable  nose  on  the  spray-valve  oper- 
ating cams  slipping.  The  clearance  between  cams  and  rollers  may  be 
too  great  or  the  valves  may  be  clogged  so  that  the  fuel  does  not  flow 
rapidly  enough.  The  cams  should  be  examined  to  see  if  they  have  slipped 
on  the  shaft;  if  they  have  not,  then  the  cam  toes  may  need  advancing 
by  means  of  the  adjusting  screws.  The  rollers  should  be  examined  to 
'see  if  any  are  badly  worn  or  broken.  Each  valve  should  be  checked  with 
the  dial  plate  or  the  valve-setting  marks  on  the  flywheel. 


Top  view  of  E.  G.  Cylinderhcad   (Nordberg  Engine) 

If  the  spray-valves  are  clogged  so  that  the  fuel  is  retarded  in  its 
passage  through  the  valves,  an  abnormal  rise  in  spray-air  pressure 
will  be  noted  if  the  compressor  suction  is  open  wide  when  the  engine  is 
turning  on  starting  air. 

The  capacity  of  the  spray-air  bottles  is  often  so  small  that  if  the 
spray-air  compressor  does  not  begin  charging  immediately  upon  start- 
ing the  engine,  the  result  will  either  be  complete  ignition  failure  or 
ignition  will  occur  for  a  few  revolutions,  then  fail  as  the  pressure 
in  the  bottles  falls.  When  this  occurs,  no  further  attempts  to  start 
should  be  made  until  the  compressor  trouble  is  located  and  remedied. 

The  most  common  cause  of  loss  of  compressor  capacity  is  broken 
or  leaky  valves.  The  location  of  the  defective  valve  may  be  determined 
by  observing  the  gage  pressures  in  the  different  stages  while  the  engine 
is  turning  over.  An  abnormal  rise  in  pressure  in  the  first  01:  second 
stage  indicates  that  air  is  leaking  back  through  the  discharge  valve  in 


128 


FUEL  FEED  AND  IGNITION 


FUEL  FEED  AND  IGNITION  129 

that  stage.  Rise  of  pressure  in  the  high  stage  may  indicate  a  closed 
stop  valve  in  the  discharge  line  to  the  engine,  clogged  strainers  or 
clogged  spray  valves. 

If  an  excessive  amount  of  lubricating  oil  is  used  in  the  compressor, 
a  jelly-like  emulsion  will  be  formed,  which  will  lodge  in  the  strainers 
and  interfere  with  air  flow.  If  the  compressor  shows  loss  of  capacity, 
with  pressure  below  normal  in  all  stages,  it  may  be  due  to  obstruc- 
tion of  the  suction  of  the  first  stage.  In  the  case  of  compressors 
that  are  regulated  by  throttling,  this  suction  loss  of  capacity  may  be 
found  to  be  due  to  the  suction  valve  being  closed. 

Another  cause  for  rapid  loss  of  jspray-air  pressure  is  sticking 
of  spray  valves.  If  a  spray-valve  stem  jams  in  its  guide  so  that  the  valve 
is  not  forced  back  to  its  seat  by  its  spring,  the  spray  air  will  blow 
into  the  cylinder  during  the  whole  cycle  and  so  much  air  will  be  blown 
away  that  the  pressure  in  the  system  will  fail.  A  condition  of  this  kind 
will  make  itself  known  by  very  severe  explosions  in  the  affected  cylinder, 
due  to  pre-ignition  of  fuel  that  has  been  blown  into  the  cylinder  too 
early  in  the  cycle. 

If  the  jacket-water  circulating  pump  is  started  before  the  engine, 
it  may  happen  that  the  cylinder  walls  and  cylinder  heads  may  be 
chilled  to  the  point  where  ignition  is  interfered  with,  this  condition 
being  most  likely  in  cold  climates,  during  the  winter  months  when  the 
cooling-water  temperature  is  very  low.  This  cooling  affects  the  ignition 
in  two  ways;  it  reduces  the  temperature  of  the  compressed  air  in  the 
engine  cylinders  and  it  also  increases  the  viscosity  of  the  fuel  oil  after 
it  is  deposited  in  the  spray-valve  cavity,  so  that  atomization  of  the 
oil  is  more  difficult  and  its  passage  through  the  valves  is  retarded. 
In  cases,  where  this  trou'ble  is  experienced,  it  is  best  not  to  start  the 
cooling-water  circulating  pump  until  after  the  engine  is  started.  When 
steam  is  available,  it  is  advisable  to  make  a  connection  to  the  water 
system  so  that  the  circulating  water  may  be  heated  and  the  cylinders 
warmed  up  before  starting  the  engine. 


FUNCTION    OF   FUEL    INJECTION    PUMP 

Inasmuch,  as  the  fuel  delivered  to  the  Combustion  Chamber  must 
be  in  excess  of  the  pressure  (from  45  to  75  atmosphere — i.  e.,  640  to 
1,100  pounds  per  square  inch)  in  the  valve  casing,  due  to  the  fuel  in- 
jection air,  the  pump  in  itself  has  to  be  exceedingly  strong  and  above 
all  mechanically  well  proportioned. 

Properly  speaking,  the  pump  regulates  the  running  of  the  engine, 
delivering  the  exact  amount  of  fuel  necessary  on  the  combustion  stroke 
corresponding  to  the  load  capacity  of  the  engine. 

It  will  be  seen,  from  the  detailed  description  of  the  different 
makes  of  engines  explained  in  this  book,  that  the  design  of  the  pump 
differs  but  very  little. 


130 


FUEL  FEED  AND  IGNITION 


The  piston  is  always  of  the  plunger  type,  made  of  steel;  the 
valve  of  bronze  material,  cast  iron  or  steel,  with  conical  seatings, 
one  suction  and  one,  or  two  in  series,  for  delivery,  loaded  with  light 
springs,  and  accessible  for  immediate  examination  or  where  the  require- 
ments of  cleaning  or  grinding  calls  for  it.  The  joints  of  the  copper 
delivery  pipes  are  usually  made  with  conical  connections. 

Almost  every  pump  is  of  a  very  massive  design,  manufactured 
of  cast  iron  body;  the  plunger  and  other  moving  parts  withstanding 
pressure  have  carefully  packed  glands. 

The  pump,  which  acts  under  control  of  the  governor  according  to 
the  load  on  the  engine  requires'  careful  attention.  In  particular,  this 
is  true  when  the  engine  runs  under  low  power,  lightly,  endeavoring  to 
supply  the  dense,  and  viscous  fuels  employed.  A  very  small  bubble  of 
air  in  the  pump  chamber  sometimes  is  the  cause  of  stopping  the  action 
of  the  pump.  The  plunger  in  its  slow  motion  merely  compresses  and  ex- 
pands the  pocket  of  air  without  causing  the  valve  to  raise. 

It  appears  to  be  difficult  to  design  a  pump  overcoming  reaction 
of  the  engine  governor  caused  by  variation  of  the  speed  requirement  of 
the  engine.  These  difficulties  usually  are  overcome  by  the  method  of 
variation  of  plunger  pump  stroke. 

While  in  many  cases  the  regulation  is  not  obtained  by  an  altera- 
tion of  the  plunger  stroke,  but  a  quantity  of  oil  corresponding  to  the 
whole  pump  cylinder  volume  passing  the  suction  valve  each  suction 
stroke. 

This  explains  the  reason  why  the  "fuel  injection  pumps  of  Diesel 
engines  draw  an  excess  quantity  of  oil  than  actually  required,  a  part 
of  this  goes  to  the  fuel  injection  valve,  the  surplus  passing  back  through 
the  suction  valve  during  part  of  the  period  of  the  delivery  stroke. 

An  oil  pump,  as 
used  on  the 
Giant  Engine,  is 
shown  in  the  il- 
lustration, this 
pump  is  operated 
by  means  of  the 
eccentric,  rocker, 
cam,  and  the 
pump  rod. 

The  quantity  of 
oil  injected  into 
the  cylinder  at 
each  stroke  of 
the  piston  is  de- 
termined by  the 
length  of  the 
stroke  of  the 
pump  plunger. 
The  length  of 


OUTLET 


INLET- 


Oil  Injection  Pump  of  the  Giant  Oil  Engine 


FUEL  FEED  AND  IGNITION 


131 


to      O 


to    to 

«£,  « 

5  & 


5 

•e  § 


132  FUEL  FEED  AND  IGNITION 

» 

this  stroke  is,  in  turn,  determined  by  the  position  of  the  plunger  cam, 
which  in  turn,  is  determined  by  the  speed  of  the  engine  governor. 

Before  attempting  to  start  the  engine,  the  pump  should  be  thoroughly 
cleaned.  This  is  best  done  by  unscrewing  the  plugs  at  the  top  and  bot- 
tom of  the  pump  body,  removing  the  steel  ball  valves,  and  washing 
out  thoroughly  with  gasoline  or  kerosene. 

In  most  engines  a  special  reservoir  is  provided,  which  usually 
is  first  filled  by  means  of  a  hand  lever.  Before  starting,  make  sure 
that  all  the  oil  pipes  and  connections  are  clean,  and  then  assure  the 
tightening  of  all  joints  eliminating  all  possibilities  of  assembling  of 
inside-air,  which  as  previously  explained,  may  cause  air  pockets. 

The  importance  of  perfect  tight  joints,  owing  to  high  compression 
pressure  must  be  emphasized.  Leaky  valves  or  connections  are  fre- 
quent occurrences,  in  particular  where  they  are  in  contact  with  high 
pressure. 

Satisfactory  operation  of  pumps  and  all  mechanical  contrivances 
depends  in  most  every  case  on  the  operator  and  the  safest  method 
of  assurance  in  proper  operation  of  the  plant  is  to  be  alert  at  all  times. 
The  cleaning  of  valves  is  a  necessary  matter  which  should  never  be 
neglected,  in  particular  where  fuel  oils  are  used  with  ash  ingredients. 


FUEL     PUMP    AND    CONTROL    END    OF    WORTHINGTON     2-CYCLE 

DIESEL    ENGINE 

Referring  to  illustration,  showing  outline  cut  of  fuel  pump  and 
control  end  of  four-cylinder  engine,  speed  regulation  is  obtained  by  open- 
ing a  by-pass  and  not  by  variation  of  the  length  of  the  fuel  pump  stroke. 

The  amount  of  fuel  supplied  to  the  cylinder  depends  on  the  time  of 
opening  of  the  by-pass  valve.  This  in  turn  depends  on  the  angular  posi- 
tion of  the  eccentric  shaft,  which  is  controlled  by  the  governor. 

The  governor,  which  is  located  on  the  end  of  the  engine  crank  shaft, 
is  connected  to  the  eccentric  shaft  by  suitable  links.  Any  increase  in 
the  engine  speed  from  normal  will  cause  the  governor  to  turn  eccentric 
shaft  through  a  small  angle  which  at  the  same  time  will  lift  end  of  by-pass 
lover.  When  the  fuel  pump  plunger  raises  the  by-pass  lever  and  by-ipass 
plunger,  by-pass  valve  will  be  opened  earlier.  As  a  result. of  this  ear- 
lier opening  of  the  by^pass  valve,  more  fuel  is  by-passed  back  to  the  fuel 
supply  reservoir,  thus  reducing  the  amount  supplied  to  the  cylinder  and 
promptly  bringing  the  speed  back  to  normal,  withont  changing  the  time 
when  injection  starts. 

Eccentrics  keyed  on  the  engine  crankshaft  drive  the  fuel  'pump 
plungers  through  tappets,  as  shown.  The  upper  ends  of  the  eccentric 
straps  are  provided  with  hardened  steel  contact  rollers  and  are  guided 
by  links,  replacing  the  crosshead  and  guide  construction  previously  used. 
The  pump  plunger  tappets  pass  through  a  partition,  which  prevents  fuel 


FUEL  FEED  AND  IGNITION 


133 


oil  leaking  down  into  the  control  housing  and  mixing  with  the  lubrica- 
ting oil.  All  running  parts  are  splash  lubricated  by  oil  from  end  main 
bearing,  overflowing  back  to  the  crank  case  pump  so  as  to  keep  a  high 
level  in  the  control  housing. 

A  hand  adjusting  screw  at  the  end  of  the  by-pass  lever  makes  it 
easy  to  equalize  the  oil  delivery  from  all  plungers  on  multi-cylinder  en- 
gines. Pump  plungers  take  oil  from  a  constantly  full  suction  tank  with  a 
strainer,  through  which  fuel  oil  is  circulated  by  the  fuel  oil  supply  pump. 


COMBUSTION    CHAMBER    AND    SPRAY    VALVE,    WORTHINGTON    2- 
CYCLE    DIESEL    ENGINE 

Referring  to  illustration  of  cylinder  head  and  spray  valve,  the  opera- 
tion of  the  spray  valve  is  extremely  simple.  The  check  valve  back  of  the 
spray  orifice  disc  is  held  on  its  seat  by  a  light  spring  and  lifted  very 
slightly  by  the  oil  flow  pressure  at  each  delivery  stroke  of  the  pump. 
The  oil  is  distributed;  to  ten  small  holes  arranged  in  a  circle  and  one 
at  the  center.  These  produce  ten  slightly  diverging  high  velocity  jets 
that  break  into  spray  near  the  injection  orifice  merging  one  into  the 


Section  of  Cylinder  and  Head  of  Worthington  Diesel  Engine   Two-cycle,. 

Solid  Injection) 


134 


FUEL  FEED  AND  IGNITION 


other  and  with  the  center  jet.  The  amount  of  fuel  injected  is  controlled 
at  the  fuel  pump  by  a  by-pass  valve  which  opens'  at  a  variable  point  of 
the  stroke  to  stop  delivery  of  oil.  The  oil  pump  is  operated  by  an  ec- 
centric on  the  end  of  the  crank  shaft.  Oil  delivery  always  starts  at  the 
same  time,,  i.  e.,  when  the  fuel  pump  tappet  strikes  the  pump  plunger. 
This  occurs  at  a  time  when  the  motion  is  rapid,  so  as  to  secure  a  quick, 
sharp  injection.  Fuel  in  a  finely  divided  state,  is  sprayed  directly  into 
the  injection  chamber  when  the  compression  is  high  enough  for  the 
air  to  ignite  the  fuel.  This  chamber!  is  completely  water  jacketed. 


Exposed  view   of  spraying   arrangement  as   used   on    Worthington   latest 
Two-cycle  Solid  Injection  Engines.    It  should  be  noted  here  that  en- 
gines of  the  Worthington  type  can  be  manufactured  from  one  H.  P.  up. 

The  small  amount  of  air  In  the  injection  chamber  receiving  the 
full  fuel  charge,  permits  only  part  of  it  to  burn,  gasifying  the  rest, 
and  without  any  shock  pressures.  The  form  of  fuel  oil  spray  is  such  as 
to  use  only  part  of  the  injection  chamber  air  during  injection.  The  un- 
burned  fuel  and  unused  air  pass  through  an  ejection  orifice  to  the  com- 
bustion chamber  when  the  pressure  in  thePinjection  chamber  is  greater 
than  in  the  cylinder,  and  complete  burning  takes  place  during  the  first 
part  of  the  downward  stroke  of  the  piston.  The  rate  of  circulation  in  the 
cylinder  is  mainly  controlled  by  the  movement  of  the  piston  itself. 

The  compression  pressure,  and  the  maximum  combustion  pressure  do 
not  normally  exceed  450  and  500  Ibs.  per  square  inch,  respectively  and  the 
latter  may  even  be  no  higher  than  the  former. 

The  non-explosive  combustion,  without  any  possibility  of  -explosive 
shock  pressure,  makes  the  expansion  as  smooth  as  possible  under  any  con- 
dition. The  engine  being  two-cycle,  every  outstroke  is  the  same,  and  this 
combined  with  the  compression  on  every  instroke  adds  greatly  to  the  per- 
fect operation  of  this  engine. 


FUEL  FEED  AND  IGNITION 


CHAPTER  VIII. 

PRINCIPLES  OF  CONSTRUCTION 
TWO-CYCLE  vs.   FOUR-CYCLE   DIESEL   ENGINES. 

The  relative  superority  of  two  or  four-cycle  internal  combustion 
engines  for  marine  purposes  is  one  of  the  most  debated  questions  at 
the  present  moment  from  a  theoretical  as  well  as  from  a  practical  stand- 
point; thus  it  forms  daily  the  subject  of  discussion,  lectures  and  articles 
in  technical  review.  The  chief  purpose  of  this  article  is  to  co-ordinate 
the  arguments  which  have  been  alleged  for  and  against  both  types  in  their 
best  form  of  construction,  and  to  endeavor  to  draw  a  conclusion  after 
careful  consideration  of  all  points  of  the  question. 

The  advantages  which  are  usually  attributed  to  the  two-cycle  engine 
as  compared  with  the  four-cycle  type  may  be  briefly  stated  as  follows: 

(A) — The  two-cycle  engine  developes  a  greater  power  than  the 
four-cycle  with  the  same  number  and  size  of  cylinders  and  the  same  num- 
ber of  revolutions.  This  advantage  of  the  two-cycle  types  is  due  to  the 
fact  that  the  four-cycle  type  gives  an  impulse  for  each  cylinder  every 
two  revolutions,  while  the  two-cycle  type  gives  an  impulse  each  revo- 
lution, theoretically  the  two-cycle  type  should  therefore  develope,  under 
the  same  conditions,  a  power  double  that  of  the  four-cycle  type.  In 
practice,  however,  the  said  theoretical  limit  has  never  been  reached,  tout 
at  present  it  may  toe  said  that  the  power  developed  toy  a  two-cycle  en- 
gine is  175  per  cent,  to  190  per  cent  of  that  of  the  four-cycle  engine, 
and  it  may  be  added  that  while  the  mean  effective  pressure  in  the  four- 
cycle type  is  about  5  kg.  per  cm.  2(  71  ib.  per  sq.  in.)  that  of  the  two- 
cycle  is  practically  of  4.4  kg.  to  4.75  kg.  per  cm.  2(  62  to  67  Ib.  per  sq.  in.). 

The  essential  advantage  of  the  two-cycle  type  brings  as  a  con- 
sequence a  remarkable  reduction  of  space  and  weight,  which  may  be 
approximately  calculated  in  the  following  manner:  As  there  is  no  reason 
that  a  four-cycle  cylinder  with  its  framing  and  driving  gear  (assuming 
the  same  Intensity  of  stress  of  the  materials)  should  weigh  less  than 
a  two-cycle  cylinder  of  the  same  size,  and  as  the  weight  can  be 
practically  considered  to  be  proportional  to  the  volume  swept  by  the 
piston,  therefore,  for  the  same  power  and  number  of  revolutions,  the 
'  cylinder  of  the  two-cycle  engine  (175  per  cent  being  taken  as  the  power 
ratio  of  the  two-cycle  to  the  four-cycle  type)  has  a  weight  which  is 
57  per  cent  of  that  of  the  four-cycle  engine. 

This  average  is  somewhat  reduced  toy  the  fact  that  the  two-cycle 
engine  needs  scavenging  pumps,  and  as,  according  to  circumstances 
and  to  the  different  design  of  the  pumps,  their  weight  can  be  considered 
as  being  8  per  cent  to  12  per  cent  of  the  weight  of  the  cylinders,  it 


PRINCIPLES  OF  CONSTRUCTION 


137 


138  PRINCIPLES  OF  CONSTRUCTION 

results  that  the  weight  of  the  two-cycle  type  will  be  62  per  cent  of 
65  per  cent  as  compared  with  the  weight  of  the  four-cycle.  The  above 
figures  seem  also  practically  confirmed,  though  there  is  always  some 
difficulty  in  comparing  numbers  quoted  by  different  constructors,  for 
they  do  not  always  state  which  parts  of  the  equipment  of  the  plant  are 
included  or  excluded  from  the  figures  published.  But  besides  the  saving 
of  weight  there  is  also  the  saving  of  space. 

It  must  be  noted  that  the  saving  of  space  by  the  two-cycle  types 
has  also  as  a  consequence  a  considerable  saving  in  the  cost  and  weight 
of  the  engine  seat  as  well  as  in  the  dimensions  of  the  engine-room, 
facilitating  the  supervision  and  control  of  the  machines. 

(B) — The  turning-moment  in  the  two-cycle  engine  is  far  more  reg- 
ular (for  the  same  number  of  cylinders)  than  in  the  four-cycle  type; 
the  results  of  even  the  four  cylinder  two-cycle  type  are  far  more  regular 
than  those  of  the  six-cylinder  four-cycle  engine. 

This  advantage  of  the  two-cycle  engine  is  not  merely  theoretical, 
but  in  practice  results  in  a  minor  intensity  of  the  vibrations  of  the 
stern  end  of  the  ship,  'besides  a  reduction  in  size  and  weight  of  the  line 
of  shafting  and  consequently  of  its  fittings,  such  as  supports,  stern 
tube,  etc.  According  to  Lloyds  Register  the  section  of  the  shafting 
of  a  six-cylinder  four-cycle  engine  (for  the  same  power  and  the  same 
number  of  revolutions)  ought  to  be  45  per  cent,  greater  than  that 
of  the  six-cylinder  two-cycle  engine.  Furthermore,  the  reduced  size 
of  the  flywheel  in  the  two-cycle  engine  and  the  reduced  space  permits 
of  placing  the  engine  nearer  the  stern,  not  only  saving  in  the  length 
of  the  line  of  shafting,  but  also  increasing  the  space  available  on 
board  for  the  cargo. 

(C) — The  two-cycle  engine  offers  greater  facility  in  reversing  as 
compared  to  the  four-cycle  type,  which  is  due  to  the  fact  that  in  the 
former  the  exhaust  of  the  burnt  gases  takes  place  thru  ports  in  the 
cylinder  wall,  so  that  in  order  to  reverse  the  running  of  the  start- 
ing valves,  the  alternation  in  the  timing  of  the  scavenging  valves  is 
very  readily  made  by  rotating  the  cam-shaft  relatively  to  the  crankshaft, 
while  the  alteration  in  the  timing  of  the  fuel  and  starting  valves  (these 
valves  having  but  a  small  lift)  can  be  readily  effected  by  employing 
double  cams  sliding  on  the  shaft. 

In  the  four-cycle  type  on  the  contrary,  besides  the  alteration  in 
the  timing  of  the  fuel  and  starting  valves,  it  is  necessary  separately 
to  reverse  the  inlet  and  exhaust  valves;  and  as  the  latter  operation  re- 
quires a  different  rotation  on  the  cam-shaft,  it  is  not  possible  to  em- 
ploy the  simple  device  of  the  two-cycle  type,  but  much  more  complicated 
mechanism  becomes  necessary. 

Referring  further,  to  the  starting  and  reversing  devices,  it  may  be 
added  that  the  necessity  of  being  able  to  start  the  engine  whatever 
be  the  position  in  which  the  cam-shaft  has  stopped,  that  phase  of  the 
starting  air  does  not  permit  of  a  reduction  in  the  number  of  cylinders 


PRINCIPLES  OF  CONSTRUCTION  139 

to  less  than  six  in  the  four-cycle  type,  while  the  two-cycle  came  can  be 
constructed  with  but  four,  and  be  kept  in  its  perfect  manoeuverability. 

(D) — With  the  two-cycle  engine  the  inertial  of  the  reciprocating 
parts  such  as  connecting  rods,  pistons,  etc.,  is  balanced  at  top-dead 
center  by  the  pressure  on  the  piston,  which  cannot  be  realized  in 
the  four-cycle  for  the  exhaust  and  suction  strokes;  as  a  consequence, 
in  the  four-cycle  type  in  order  to  avoid  the  possibility  of  their  break- 
ing and  the  great  damage  this  would  cause. 

(E) — The  two-cycle  engine  does  not  require  any  exhaust  valve  for 
the  burnt  gases,  and  in  the  engine  provided  with  port  scavenging  there 
is  no  need  of  any  valve  subjected  to  the  action  of  the  burning  gases; 
in  the  four-cycle  type  the  exhaust  valves  are  the  source  of  well  known 
troubles  and  even  in  the  case  their  tightness  and  durability  is  increased 
by  using  more  or  less  complicated  cooling  devices,  the  danger  of 
their  falling  into  the  cylinder,  with  all  its  serious  consequences,  can 
never  be  fully  eliminate. 

It  should  be  noted  that  the  exhaust  valves  of  the  four-cycle  engine 
are  the  parts  which  are  the  most  sensitive  to  the  quality  of  fuel  and 
are  especially  liable  to  suffer  by  the  asphaltum  and  sulphur  sometimes 
present  in  heavy  oils  of  certain  origins.  For  a  two-cycle  engine  without 
exhaust  valves  there  may  consequently  be  used  certain  kinds  of  fuel 
which  are  not  suitable  for  a  four-cycle  engine. 

Against  the  advantages  above  referred  to  as  to  the  two-cycle  type, 
the  advocates  of  the  four-cycle  engine  oppose  some  objections  which 
partially  apply  to  all  two-cycle  engines;  and  partially  apply  to  special 
types  or  to  constructive  details  of  them.  These  objections  may  be 
briefly  stated  as  follows: 

(a) — In  favor  of  the  four-cycle  type  it  has  been  said  that  the  ex- 
perience of  the  gas  engine  has  lead  back  again,  (after  a  period  of  pre- 
ference for  the  two-cycle  engine,  so  that  it  is  convenient  to  select  again 
the  four-cycle  type). 

Against  this  objection  we  may  note  that  the  example  of  the  gas 
engine,  as  compared  with  the  four-cycle,  shows  the  disadvantage  of 
a  greater  consumption  and  of  the  inefficient  regulation  at  light  loads; 
the  greater  consumption  being  due  to  the  fact  that  a  certain  amount  of 
gas  is  always  mixed  with  the  scavenging  air  because  the  two  fluids 
cannot  remain  wholly  separated,  and  so  unburnt  gas  escapes  with  the  air 
thru  the  exhaust  ports  without  producing  any  useful  work.  The  bad 
regulation  is  due  to  the  difficulty  of  having  the  right  mixture  in  case 
of  light  loads,  because  in  the  two-cycle  engine  it  is  impossible  to 
regulate  the  power  without  diluting  the  explosive  mixture.  Neither  of 
the  said  inconveniences  exist  in  the  Diesel  engines,  the  scavenging  being 
made  with  pure  air  and  the  regulation  being  obtained  in  exactly  the  same 
manner  in  both  the  two-cycle  and  in  four-cycle  types.  Moreover,  it 
may  be  stated  that  notwithstanding  the  said  inconveniences,  which  can- 
not be  neglected,  the  gas  two-cycle  engines  are  still  constructed,  and 


140  PRINCIPLES  OF  CONSTRUCTION 

in  work  for  many  hundred-thousands  of  horse-power,  from  which  we  may 
draw  the  conclusion  that  the  two-cycle  engines  offer  other  real  advan- 
tages. 

More  suitable  than  the  example  of  the  gas  engine  for  comparison 
is  that  of  the  hot-bulb  engines  where  the  two-cycle  type  is  preeminent, 
for  the  Bolinder,  Skandia,  Fairbanks-Morse,  Petter,  Torbinia  types, 
a.  s.  o.,  have  almost  completely  eliminated  the  competition  of  the  four- 
cycle type,  especially  for  high  power. 

Referring  now  to  some  failures  of  the  two-cycle  Diesel  engine, 
it  may  be  said  they  are  mainly  due  to  constructive  defects;  numerous  in- 
conveniences have  been  experienced  in  the  engine  with  stepped  pistons, 
and  it  would  therefore  be  wrong  to  attribute  these  failures  to  the  type 
of  the  engine  in  itself,  instead  of  to  defects  in  design. 

The  supporters  of  the  four-cycle  type  allege  that  the  two-cycle 
engines  are  far  more  complicated,  not  only  on  account  ofi  the  scaveng- 
ing pumps,  the  piping  and  the  receivers  relating  thereto,  but  also  on 
account  of  the  greater  complexity  of  the  valve  gear. 

Against  this  assertion  it  may  be  objected  that  the  air  pumps 
which  undoubtedly  constitute  an  added  organ,  by  no  means  interfere  with 
the  reliability  of  the  working  of  the  engine,  as  they  are  always  working 
at  very  low  pressures  and  temperatures,  like  the  low-pressure  cylinders 
of  steam  engines;  and  constructively  it  is  certainly  more  rational  to 
employ  a  suitable  air  pump  instead  of  using,  for  half  the  time,  for 
displacing  the  air,  enormous  pistons  which  have  been  designed  and  fitted 
with  rings  for  at  least  a  hundred  times  higher  pressure. 

Referring  now  to  the  valve  gear,  the  complexity  pertains  exclusively 
to  that  two-cycle  type  of  engine  having  scavenging  valves  in  the  cylinder 
heads,  whilst  in  the  recent  type  with  port  scavenging,  besides  the 
fuel  and  the  starting  valve  (like  that  of  the  four-cycle  type),  there 
is  only  the  scavenging  valve  to  control.  This  is  light  and  easily  dis- 
placed, as  it  is  not  subjected  to  the  highest  pressures  and  temperatures 
of  the  cycle,  and  it  does  not  require  to  be  perfectly  tight.  This  valve 
can  easily  be  replaced  by  a  rotary  valve.  In  the  cylinder  of  the  four- 
cycle engine,  instead  of  one  scavenging  valve  there  are  two  at  least  to 
be  controlled,  and  very  often  two  inlet  and  two  exhaust  valves,  which, 
being  placed  in  the  combustion  chamber,  require  to  be  perfectly  tight  and 
need  an  precise  and  reliable  operating  gear  in  order  to  withstand  the  ef- 
fort of  the  powerful  closing  springs. 

In  favor  of  the  four-cycle  type  it  has  been  furthermore  affirmed 
that  its  fuel  consumption  is  far  lower  than  that  of  the  two-cycle  engine. 
Now  even,  if  it  must  be  admitted,  that  this  objection  is  correct  in  re- 
lation to  the  first  two-cycle  engines  which  were  constructed,  and  is 
also  applicable  to  some  present  motors  of  defective  construction,  it  has, 
nevertheless,  lost  much  of  its  importance  when  comparing  the  four-cycle 
engine  with  the  best  known  modern  two-cycle  engines. 

't  is  true,  that  some  excessively   low  figures  have  been  singly  re- 


PRINCIPLES  OF  CONSTRUCTION  141 

ported  for  the  consumption  of  four-cycle  engines,  but  they  can  toe  safely 
overlooked  upon  consideration  of  the  circumstances  of  the  test  or  of  the 
uncommonly  high  consumption  of  the  lubricating  oil,  which,  has  obviously 
partially  burnt  as  fuel,  so  that  the  above  stated  results  can  be  quoted 
as  corresponding  to  the  best  up-to-date  constructions.  Though  they  still 
show  a  slight  advantage  for  the  four-cycle  engine,  this  is  no  greater 
than  3  per  cent,  or  5  per  cent,  and  if  we  consider  the  other  element  re- 
quired for  calculating  the  real  working1,  expenses,  this  difference  is  not 
of  great  importance.  It  must,  indeed,  be  noted  that  the  installation  of 
two-cycle  instead  of  four-cycle  engines  for  a  given  type  of  ship,  results 
in  a  saving  in  weight  and  space,  and  therefore  a  reduction  of  displace- 
ment and  the  possibility  of  increasing  the  run  of  the  stern  (this  leading 
to  a  reduction  in  the  power  for  propelling  the  weight  and  the  space 
taken  by  the  propelling  plant)  have  the  greatest  influence.  Furthermore, 
it  may  be  added  that,  even  if  the  question  of  the  weight  and  space  should 
be  regarded  as  a  secondary  one,  sftill  the  two-cycle  engines  show  the  ad- 
vantage that  the  particulars  being  the  same,  it  can  develope  the  same 
power  as  the  four-cycle  one  at  a  much  lower  speed  revolution,  with  the 
consequence  of  rational  and  systematic  experiments,  in  a  few  years,  from 
250  grams  or  260  grams  per  brake  horse  power,  to  the  present  values,  it 
will  still  improve  until  it  reaches  and  even  surpasses  the  low  consump- 
tion of  the  four-cycle  type.  Theoretically,  there  is  no  reason  why  this 
should  not  happen,  for  the  thermal  efficiency  is  the  same  in  both  types, 
and  the  power  required  by  the  two-cycle  engine  cannot  be  greater  than  the 
power  expended  in  driving  the  main  pistons  of  the  four-cycle  engine  to 
work  half  the  time  as  pumps  themselves. 

Finally,  besides  the  fuel  consumption,  that  of  the  lubricating  oil, 
which  is  much  more  expensive,  ought  to  be  considered.  It  is  obvious 
that  the  two-cycle  engine  should  require  a  less  quantity  of  oil  than  the 
four-cycle,  the  load  on  the  piston  of  the  four-cycle  engine  being  50  per 
cent  greater  (with  the  same  number  of  cylinders  and  the  same  ratio  be- 
tween diameter  and  stroke)  than  that  of  the  two-cycle,  the  pressure 
exerted  on  the  bearings,  and  on  the  guides  being  proportionately  increased 
so  that  the  surafec  to  be  lubricated  is  accordingly  larger.  In  practice, 
however,  as  the  two-cycle  engine  may  be  constructed  with  fewer  cylin- 
ders the  saving  in  the  lubricating  oil  is  still  more  evident.  At  present  the 
figure  of  3  grammes  to  4  grammes  (0.00614  Ib.  to  0.008818  Ib.)  per  brake 
horse-power  as  the  total  amount  of  oil  consumption  is  usually  reached  in 
high  speed  engines  (480  revolutions). 

As  another  advantage  of  the  four-cycle  type,  it  is  affirmed  that  the 
cylinder  wall  never  reaches  such  high  temperature  as  in  the  two-cycle 
type,  so  that  the  latter  are  subjected  to  higher  internal  strains  and 
thus  to  the  danger  of  cracks.  Now,  while  it  is  true  that  the  ratio 
between  the  quantity  of  fuel  burnt  in  the  four-cycle  type  and  the  surface 
of  the  combustion  chamber  is  hardly  superior  to  one-half  the  same  ratio 
in  the  two-cycle  engine,  other  important  circumstances  have  been  over- 
looked which  have  certainly  a  great  influence  on  the  mean  temperatures. 


142  PRINCIPLES  OF  CONSTRUCTION 

The  action  of  the  hot  gases  on  the  cylinder  walls  lasts  certainly 
a  shorter  time  in  the  two-cycle  than  in  the  four-cycle  type.  While  in  the 
latter  the  cylinder  walls  undergo  the  action  of  the  hot  gases  during 
the  whole  expansion  and  exhaust  strokes,  that  is,  practically  for  more 
than  half  the  time,  in  the  two-cycle  engine  the  action  of  the  hot  gases 
lasts  only  for  a  little  more  than  two-thirds  of  the  working  stroke, 

In  the  two-cycle  engines  in  which  the  exhaust  occurs  thru  ports, 
the  latter  open  much  more  rapidly  than  the  exhaust  valves  of  the  four- 
cycle engines,  and  consequently  there  is  a  much  more  rapid  diminution 
in  the  temperature  due  to  expansion. 

While  the  exhaust  temperature  in  the  four-cycle  engines  is  seldom  be- 
low 350  degrees  D.  and  in  the  high  speed  engines  is  easily  reached  450  deg. 
or  500  deg.  C.,  in  two-cycle  engines,  if  well  constructed,  this  tempera- 
ture usually  remains  under  250  deg.  C.,  and  sometimes  it  only  reaches 
200  deg.  or  210  deg.  C. 

Not  one  of  the  hypotheses  above  referred  to  is  in  the  favor  of  the 
two-cycle  engine;  the  hypothesis  of  the  same  initial  compression  tem- 
perature in  both  types  is  unfavorable  for  the  two-cycle  type,  as  all 
experiments  which  have  been  made  with  gas  engines  confirm  that  in  the 
two-cycle  engines  a  much  higher  compression  ratio  can  be  employed  than 
in  the  four-cycle  engine,  without  the  danger  of  pre-ignition,  and  that 
the  mixture  in  the  beginning  of  the  compression  is  therefore  cooler  in 
the  two-cycle  type.  By  measuring  the  diagrams  with  a  plainmeter,  how- 
ever, the  conclusion  was  reached  that  the-  mean  temperature  of  the  two- 
cycle  is  practically  the  same. 

Taking  account  of  all  these  elements  it  is  fair  to  say  the  two- 
cycle  engine,  from  the  standpoint  of  temperature,  is  in  better  condi- 
tion than  the  four-cycle.  The  two-cycle  engine,  in  which  the  inner 
walls  of  the  cylinder,  after  the  very  short  action  of  the  flame,  are  im- 
mediately colled  by  the  scavenging  air  current  (which  is  supplied  in 
such  quantity  as  to  allow,  besides  the  filling  up  of  the  cylinder,  the 
escape  of  the  warmest  portion  which  entered  at  first)  is  thermally 
superior  to  the  four-cycle  engine,  in  which  all  heat  must  be  abstracted 
thru  the  walls  of  the  cylinders  with  the  consequent  fall  of  the  tempera- 
ture in  the  walls  and  resultant  internal  stresses. 

The  opponents  of  the  two-cycle  engine  allege  that  the  engines  of 
this  type  some  portion  of  the  combustion  gases  remains  in  the  cylinders, 
especially  in  the  upper  part  of  them,  so  that  the  cylinder  head  becomes 
excessively  hot.  Against  this  argument  it  must  be  first  remarked  that 
in  the  foor-cycle  engine  at  least  8  per  cent  of  the  burnt  gases  remain 
to  fill  the  compression  chamber  when  the  piston  has  completed  the 
exhaust  stroke,  and  it  is  obvious  that  this  remaining  portion  cannot  but 
contaminate  the  air  which  is  drawn  in  during  the  subsequent  stroke.  As 
regards  to  the  two-cycle  engine  the  assertion  that  some  residue  of  the 
'burnt  gases  still  remain  in  the  cylinder  after  the  scavenging  operation 
is  merely  a  gratuitous  hypothesis,  which  is  contradicted  by  the  facts 
above  referred  to,  according  to  which  the  quantity  of  heat  absorbed  by 


PRINCIPLES  OF  CONSTRUCTION  143 

the  walls  is  less  than  in  the  two-cycle  engine,  and  that  in  the  two-cycle 
type  the  compression  ratio  can  assume  a  greater  value  in  the  four-cycle 
engines. 

Against  the  four-cycle  engine  it  has  been  said  that  the  four-cycle 
type  can  run  with  greater  regularity  than  the  two-cycle  when  work- 
ing at  low  speed  of  revolutions,  owing  to  the  fact  that  in  the  two-cycle 
engine  the  compression  at  low  speed  falls  rapidly  with  the  diminish- 
ing of  the  scavenging  air  pressure.  It  must,  however,  be  noted  that  this 
observation  is  correct  merely  when  it  refers  to  two-cycle  engines  of 
bad  design,  in  which,  owing  to  inefficient  construction,  the  scavenging 
air  pressure  rises,  at  the  normal  speed,  to  excessively  high  value,  while 
in  the  two-cycle  engines,  which  have  been  carefully  designed  even  at  full 
speed  the  pressure  of  the  scavenging  air  remains  within  very  small  limits. 
By  the  speed  reduction  the  pressure  is  also  somewhat  reduced,  but  not  so 
as  to  cause  failure  of  the  ignition  especially  when  the  engine  is  hot. 
Practically,  in  both  the  two  and  four-cycle  types,  the  lowest  limit  of 
speed  is  dependent  upon  the  two-cycle  engines  is  more  than  efficient  for 
perfect  manoeuvering.  Moreover,  it  must  be  remarked  that  the  turning 
moment  of  two-cycle  engines  being  more  regular,  and  it  being  possible 
to  run  with  half  the  number  of  cylinders  and  to  obtain  sufficiently  good 
regularity,  the  two-cycle  engine  shows  in  this  particular  point  an  ad- 
vantage compared  with  the  four-cycle  type. 

Authors  Note:  In  above  article  it  should  be  noted  that  compari- 
son of  the  two-stroke-cycle  vs.  four-stroke-cycle  type  of  Diesel  engines 
depends  a  great  deal  on  the  view  of  manufacturers.  Each  builder 
naturally  stands  for  the  type  of  his  particular  make  of  engine.  Both 
types,  as  will  be  seen,  have  their  advantages  and  also  disadvantages, 
depending  on  the  class  of  work  they  are  performing.  While  the  viewpoint 
expressed  in  this  article  represents  the  stand  Mr.  Giovanni  Chiesa  of  the 
Ansaldo  San  Giorgio  Works  of  Turin,  Italy,  the  stand  taken  by  Mr. 
Franco  Tosi  of  Legnano,  Italy,  again  entirely  claims  the  superiority 
of  the  four-cycle  construction  for  Diesel  Machinery,  as  will  toe  seen 
in  the  article  dealing  with  the  advantage  of  the  four-cycle  over  the 
two-cycle  type. 


POINTS    OF    ADVANTAGE     AND     DISADVANTAGE     OF    TWO-CYCLE 
IN  COMPARISON  TO  THE  FOUR-CYCLE  DIESEL  ENGINE. 

In  this  section  dealing  with  the  advantages  claimed  on  engines  built 
on  four-cycle  principle,  some  conclusion  may  be  gained  when  comparing 
the  arguments  advanced  by  adherents  to  the  two-stroke  cycle  as  set  forth 
in  previous  pages. 

The  controversy  as  brought  before  the  readers  of  this  book,  should 
bring  out  many  points  in  favor  of  either  engine.  For  instance,  it  is 
claimed  by  those  preferring  the  four-stroke  type,  that  if  the  same  life  is 
to  be  obtained  from  the  two-stroke  cycle  engine  in  comparison  to  its  rival, 


144 


PRINCIPLES  OP  CONSTRUCTION 


PRINCIPLES  OP  CONSTRUCTION 


145 


146  PRINCIPLES  OP  CONSTRUCTION 

any  advantage  of  reduced  space  and  weight  which  it  may  possess  disap- 
pears. Advocates  of  the  two-stroke  cycle  engine  give,  as  one  of  the  prin- 
cipal reasons  in  favor  of  this  type  of  engine,  the  greater  power  that  can 
be  developed  in  a  given  size  of  cylinder;  but  this  advantage  is  only  ob- 
tainable at  the  expense  of  the  greatly  increased  temperature  of  the  cylin- 
der, piston  heads,  etc.,  which  arises  from  the  combustion  of  the  larger 
quantity  of  fuel  necessary  for  the  increased  power  per  cylinder. 

The  ratio  of  increase  in  consumption  of  fuel  per  cylinder  of  equal 
size,  is,  in  fact,  greater  than  the  ratio  of  increase  of  the  power  obtained 
from  the  cylinder,  the  consumption  of  fuel  per  horse-power  .hour  being 
somewhat  greater  in  the  two-cycle  engine  than  in  the  four-cycle.  This 
greater  quantity  of  heat  developed  in  each  cylinder  in  a  given  time  and 
the  resulting  higher  temperature  is  confirmed  by  the  color  of  the  surfaces 
of  the  part  exposed  to  it,  and  is  responsible  for  the  trouble  that  have  been 
experienced  in  the  two-stroke  engine. 

It  follows,  therefore,  that  the  two-stroke  cycle  engine,  if  designed 
with  the  same  size  of  cylinder,  will  have  a  shorter  life  and  may  require 
more  frequent  overhauling  than  an  engine  of  the  four-cycle  type.  This 
is  a  fact  of  great  importance  not  only  with  heavy  oil  engines  for  cargo 
boat  propulsion,  which  must  run  uninterruptedly  at  long  periods  at  full 
load,  but  also  for  the  lighter  type  of  engine  used  for  submarines  which, 
although  not  required  to  run  fully  loaded  for  such  long  periods,  are  sub- 
jected to  high  stresses.  Considerable  progress  has  doubtless  been  made 
with  the  two-cycle  engine,  and  many  improvements  introduced  into  the 
design,  material,  cooling  of  the  cylinder  and  piston,  to  overcome  the  dif- 
ficulties experienced.  The  modern  two-cycle  engine  is  thus  undoubtedly 
more  reliable  than  the  older  types,  but  such  engines  have  been  in  service 
for  too  short  a  time  for  a  definite  judgment  on  them  to  be  arrived  at.  On 
the  other  hand,  rapid  progress  has  also  been  made  in  the  design  of  the 
four-stroke  cycle  engine,  whilst  many  years  of  highly  satisfactory  service 
at  full  load  have  already  been  recorded.  Regarded  in  another  way,  if  an 
equal  life  is  required  from  both  types  of  engine — which  is  called  for  in 
both  land  and  marine  service — an  equal  quantity  of  fuel  should  in  both 
types  be  consumed  in  a  cylinder  of  a  given  size,  in  order  to  secure  equal 
temperatures.  If  this  condition  is  adhered  to  the  result  will  be  that  the 
same  power  will  be  developed  by  both  types  with  an  approximately  equal 
weight  and  space. 


PRINCIPLES    OF    DOUBLE-ACTING     PISTON     DIESEL     ENGINES 

While  the  single-acting  piston  Diesel  engine  has  been  universally 
adopted,  principally  on  account  of  its  superiority  in  regards  to  simplicity, 
nevertheless  there  are  factors  of  numerous  advantages  in  favor  of  the 
double-acting  piston  type.  From  the  earlier  experiments  carried  out  in 
Germany  by  von  Oechelhauser  and  Junkers,  up  to  the  present  day,  this 
type  has  been  brought  to  a  highly  commendable  stage  of  perfection. 


PRINCIPLES  OF  CONSTRUCTION 


147 


The  constructive  principles  on  double-acting  Diesel  engines  prove  that 
there  are  features  which  cause  a  high  attaining  of  power  with  consider- 
able less  fuel  expenditure  than  on  engines  of  single-acting  types.  On  this 


wellknown  Junkers  engine.     A   German   product  which  has   many 
advantages  as  a  double-acting-piston  engine  over  her  rival  the  single- 
acting-piston 

account  alone  an  important  point  is  gained,  balancing  any  questionable 
performance  in  contrast  to  the  single-acting  engine.  While  experiments 
with  gas-engines,  working  on  the  opposed-piston  principle,  have  proven 


148 


PRINCIPLES  OF  CONSTRUCTION 


PRINCIPLES  OF  CONSTRUCTION  .  149 

highly  satisfactory,  it  should  be  considered  that  problems  on  Diesel  en- 
gine operation,  or  constant  pressure  application,  require  problems  to  be 
solved  inherent  to  this  class  of  engine. 

In  following  explanation  it  will  be  observed  that  there  are  factors  of 
advantage  in  favor  of  the  opposed  type  of  Diesel  engine. 

(1)  The  subdivision  of  the  aggregate   stroke  by  using  two  pistons 
achieves  a  large  ratio  of  stroke  to  diameter  of  cylinder  simultaneous  with 
a  high  rate  of  revolution,  and  thus  induces  favorable  conditions  in   re- 
gard to  general  economic  and — due  to  the  favorable  combustion  chamber — 
heat  economic  circumstances. 

(2)  The  use  of  two  pistons  and  the  exhibited  solution  of  the  mechan- 
ism, connecting  them,  with  the  crankshaft,  enable  far  reaching  balance  of 
reciprocating  parts;   a  far  reaching  relief  of  the  main  bearings;    taking 
up  the  forces  exerted  by  the  pistons  in  the  mechanism  itself. 

(3)-  The  engine,  constructed  on  the  two-cycle  principle  with  its  eco- 
nomic advantages,  provides  good  scavenging  by  the  aid  of  pistons.  These, 
with  their  large  diameter  and  stroke,  represent  absolutely  ideal  govern- 
ing elements  as  well  as  exhaust  and  the  admittance  of  scavenging  air. 

(4)  The  main  parts  of  the  engine  only  experience  undue  strains  and 
stresses  as  are  created  by  useful  external  forces,  and  are  free  from  uncon- 
trollable and,  therefore,  causing  reliability  of  operation,  heat  and  internal- 
strains  due  to  casting. 

(5)  Higher  thermal  efficiency  with  its  consequential  results  of  a  high 
utilization  of  the  fuel.    Uniform  maintainance  of  heat  temperature  adding 
towards  regularity.     Larger  cylinder  volume  per  power-unit  convertible 
into  useful  work. 

The  method  of  tandem-arrangement  in  opposed-piston  practice,  has 
also  proven  highly  satisfactory.  In  this  particular  system  the  two  outer 
pistons  act  directly,  and  by  medium  of  the  power-transmitting  mechanism 
on  the  center  crank.  The  two  inner  pistons  are  connected  by  transverse- 
piece  and  the  side-rods  on  the  side-cranks.  These  are  set  180°  with  refer- 
ence to  the  middle  crank.  As  the  particular  type  under  discussion  works 
on  the  two-cycle,  the  general  arrangement  produces  double  action,  i.  e., 
every  stroke  is  a  working  stroke.  While  the  pair  of  pistons  in  the  one 
cylinder  are  executing  an  outward  movement,  i.  e.,  a  power  stroke,  the 
pair  of  pistons  in  the  other  cylinder  approach  each  other,  i.  e.,  to  accom- 
plish a  compression  stroke,  and  vice  versa.  When  the  pistons  of  the  one 
cylinder  have  reached  their  inner  dead  center,  the  pistons  of  the  other 
cylinder  have  attained  their  outer  dead-center  position. 

The  scavenging  process  is  accomplished  in  following  manner: 

At  first  the  one  row  of  ports  is  opened  by  the  one  piston  and  the  spent 
gases  take  their  exit,  seeking  an  equalization  of  pressure  with  that  of  the 
atmosphere.  Hereupon  the  other  ring  of  slots  is  laid  bare  by  the  second 
piston  and  a  quantity  of  air  delivered  by  the  scavenging  pumps  at  low 
pressure,  is  admitted  to  the  cylinder.  This  expels  the  products  of  com- 


150  PRINCIPLES  OF  CONSTRUCTION 

bustion,  driving  them  away  in  front  of  itself,  leaving  the  cylinder  as  free 
from  residue  as  possible.  Thus  in  this  scavenging  process  the  function  of 
governing  the  ports  in  the  circumference  of  the  cylinder  devolves  on  the 
pistons.  The  working-process  during  one  revolution  is  identical  to  all 
two-cycle  engines,  i.  e.,  (a)  admission,  (b)  compression,  (c)  power-stroke, 
and  (d)  exhaust. 

Every  cylinder  is  provided  with  a  fuel-injection  valve.  The  forward 
cylinder  receives  in  addition  a  compressed-air  starting  valve.  At  both 
sides  of  the  rear  cylinder  the  double-acting  scavenging-pumps  are  ar- 
ranged. These  are  actuated  by  the  middle-traverse  piece.  In  the  same 
line  to  the  rear  each  of  two-stages  of  the  four-stage  or  three-stage  air- 
compressors  are  fitted.  The  valve-gear  of  the  engine  is  actuated  by  cams. 
The  driving-shaft  runs  through  under  the  engine.  For  each  cylinder  it 
drives  two  short  cam  shafts  carried  by  rocking  frames,  for  ahead  and  re- 
versing, respectively.  By  rotating  the  rocking  supports  about  the  center 
line  of  the  driving-shaft  from  the  controlling-platform  the  ahead  and  re- 
versing cams  may  be  brought  into  contact  with  the  valve-lever  roller,  res- 
pectively. On  each  of  the  cam  shafts  a  starting-cam  is  situated  between 
two  injection  cams.  The  lower  fuel-valve  on  each  cylinder  is  actuated 
directly  by  a  lever.  The  other  valve  is  worked  by  a  circuit  of  rods  lead- 
ing to  the  top  of  the  cylinder.  The  moving  of  the  starting  valve  is  effected 
by  medium  of  an  interposed  lever.  The  three  rollers  for  each  cylinder  are 
placed  axially  relatively  to  one  another.  The  interposed  lever  for  actuat- 
ing the  starting-valve  is  mounted  on  an  eccentric  journal,  so  that  it  can 
be  put  out  of  action  by  the  levers  leading  to.  the  controlling-platform.  For 
reversing  it  is  only  necessary  to  swing  the  rocking-frames  over  and  keep 
the  starting-valves  in  action  till  the  engine  is  rotating  in  the  contrary 
sense. 


EFFECTS  OF  INTERNAL  AND  EXTERNAL  STRESSES 

The  importance  of  designing  Diesel  engines  eliminating  all  possibility 
of  undue  stresses  of  either  internal  or  external  forces  is  imperative.  Not- 
withstanding the  possibility  of  restricting  the  stresses  set  up  in  materials 
of  other  prime  movers  to  external  forces,  when  the  cylinder-walls  and  cor- 
responding parts  are  suitably  proportioned;  it  is  utterly  impossible  to  ob- 
viate stresses  produced  by  internal  forces,  where  there  is  a  permanent 
heat-flux  and  a  consequent  temperature-difference  to  be  dealt  with.  Such 
is  the  case  with  the  cylinder-walls  in  the  internal  combustion  engine. 

The  large  difference  in  the  heat-transfer  per  unit  of  surface  at  the 
single  sections  of  the  shell  must  be  considered.  Under  the  influence  of  the 
temperature-difference  the  hot  cylinder  sections  tend  to  expand  more  than 
the  colder  ones.  Thus,  the  shell  experiences  a  strain  due  to  tensile  or 
compressive-stresses.  This  is  again  balanced  by  expansion  due  to  an 
equalization  of  heating,  an  augmented  flow  of  heat  is  natuarlly  to  be  an- 
ticipated. This  is  to  be  accounted  for  by  the  piston  conducting  the  heat 


PRINCIPLES  OF  CONSTRUCTION 


151 


taken  up  at  its  bottom  to  the  external  and  internal  cylinder  parts,  distrib- 
uting the  heat  from  the  hotter  cylinder-sections  to  the  cooler  ones,  laying 
more  remote  from  the  combustion  space. 

In  a  case  where  the  shell  contains  a  hole,  the  fibre  in  the  vicinity  ot 
the  boundary  of  the  perforation  experience  a  stronger  strain,  causing  a 
consequential  danger  of  cracking  of  material.  The  reducing  of  heat- 
stresses,  inevitable  in  the  internal  combustion  engine,  and,  increasing 
tremendously  with  the  sizea  of  modern  engines  of  large  capacities,  to  tol- 
erable values,  by  appropriate  measures,  is  a  problem  which  requires  con- 
sideration. Combustion  chambers  should  be  provided  with  plain  walls, 
possible  to  withstand  the  severest  heat-impulses. 


Engine  Frame  of  Standard  Engine   (Vertical  Type) 

Correct  designs  of  cooling-arrangements  obviating  as  far  as  possible 
existing  high-temperatures  difference  is  also  a  factor  which  deserves  men- 
tion. Provisions  in  designing  two-cycle  engines,  creating  a  governing 
element  for  scavenging,  which  with  great  simplicity  and  reliability  of  op- 
eration would  perfectly  satisfy  the  important  conditions  to  be  enforced, 
are  of  material  importance.  These  consist  in  opening  and  closing  exhaust 
and  scavenging-areas  as  rapidly  as  possible. 

It  has  been  found  that  the  design  of  the  cylinder,  to  correspond  with 
thermal  considerations,  is,  to  make  them  of  small  diameter  and  long 
stroke,  so  that  the  heat-efflux  during  compression,  especially  in  the  last 
part  of  the  same,  is  curbed  as  far  as  possible,  insuring  positive  ignition 
even  at  low  rates  of  revolution. 

The  increased  volume-pressure  attending  the  combustion  and  expan- 


152 


PRINCIPLES  OP  CONSTRUCTION 


sion  with  increased  output,  and  the  thus  augmented  heat-transfer,  in  spite 
of  the  temperature  remaining  the  same,  calls  for  observation  in  the 
evolvement  of  Diesel  construction.  The  method  of  increasing  the  output 
is  not  so  much  of  importance  as  the  process  of  increasing  the  pressure. 
The  pressures  growing  proportionally  with  increased  work  and  gain  in 
power  must  be  well  endurable  by  the  cylinder  walls  and  other  sections 
of  the  engine,  minimizing  all  stresses. 


Cylinder  construction    to   resist    tension   in   addition    to   bursting   strain, 
is  a  factor  exceedingly  vital 


Pressures  due  to  the  inertia  of  the  reciprocating  parts,  growing  pro- 
portional to  the  square  of  the  number  of  revolutions,  is  in  itself  a  prob- 
lem which  requires  intimate  knowledge.  As  the  working  pressures;  have 
gained  in  the  same  measure,  the  resulting  piston-forces  and  the  tangen-' 
tial-forces  as  well  as  the  surplus  work-areas  determining  the  coefficient 
for  the  fluctuation  of  speed,  resulting  in  increased  external  strains.  As 
the  compression  terminal-pressure  and  the  pressure  of  combustion  grow 
proportional  with  the  increase  of  output,  a  higher  rate  of  revolution  is 
to  be  expected,  as  far  as  this  is  not  restricted  by  the  inertia-forces.  To 
judge  the  conditions  of  importance  in  Diesel-operation,  the  bearing-loads 


PRINCIPLES  OF  CONSTRUCTION 


153 


resulting  from  the  acting  piston-forces  and  the  inertia-loads  resulting 
from  the  inertia-forces;  the  unbalanced  forces  and  tilting-moments  in 
engines  of  either  the  two-cycle  or  four-cycle  type,  requires  practical 


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£  s 

P-     co 


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knowledge  combined  with  theory.  The  measurements  for  the  mechanism 
and  other  vital  sections  should  be  computed  on  the  assumption  of  equal 
stresses  with  respect  to  strength  and  equal  specific  uniform-pressures. 


154 


PRINCIPLES  OF  CONSTRUCTION 


SCAVENGING  ARRANGEMENTS 


The  necessity  of  providing  scavenging  pumps  on  two-cycle  engines 
and  such  problems  arising  in  conjunction  with  this  vital  arrangement, 
in  particular  on  larger  types,  is  a  factor  which  enters  in  this  subject 
under  discussion. 

The  principal  requirement  of  two-cycle  operation  demands  thorough 
scavenging  of  its  cylinders  of  all  burned  substances.  Remainder  of 
these  gases  will  have  a  tendency  to  decrease  the  capacity  of  the  ma- 
chine. Designers  of  BusclnSulzer  large  two-cycle  engines  have  laid  par- 
ticular stress  on  this  matter  of  intrinsic  importance  as  will  be  observed 
in  the  description  of  this  respective  type. 


r 


Cylinder  of  "Standard"  Horizontal   Type  of  Diesel  Engine. 
A  result  of  careful  investigation. 

Scavenging  comprises  two  functions — the  clearing  of  the  cylinder 
of  the  products  of  the  previous  combustion,  or  burnt  gases,  by  means  of 
a  current  of  air,  and  the  supply  of  the  air  charge  necessary  for  the  next 
combustion. 

A  very  distinctive  feature  is  the  Sulzer  Patented  Scavenging  and 
Charging  System. 

Two   general  methods  are   employed — head    scavenging    and    port- 


PRINCIPLES  OF  CONSTRUCTION  155 

scavenging- — and  one  or  the  other  of  these,  in  its  older  form,  is  still  used 
on  all  types  of  two-cycle  Diesel  engines,  excepting  Sulzer's  of  European 
construction  and  the  American  Busch-Sulzer's. 

Head-scavenging — in  which  the  scavenging  air  enters  the  cylinder 
through  valve-controlled  openings  in  the  cylinder  head,  and  the  burnt 
gases  are  blown  out  through  piston-controlled  ports  in  the  cylinder  wall — 
necessitates  the  use  of  one  or  more  comparatively  large  valves  in  the 
cylinder  head,  rendering  the  head  particularly  susceptible  to  fracture 
due  to  heat  stresses.  This  fault  has  proved  so  serious,  and  so  entirely  un- 
avoidable that  there  is  now  a  general  tendency  among  builders  of  two- 
cycle  Diesel  engines  to  discard  head-scavenging  altogether. 

Port-scavenging — in  which  the  scavenging  air  enters  the  cylinder 
through  piston-controlled  ports  in  the  cylinder  wall,  and  the  burnt  gases 
are  blown  out  through  similar  ports — while  it  overcomes  the  cracking 
of  the  cylinder  head,  possesses,  in  its  ordinary  form,  characteristics 
which  affect  the  engine  detrimentally.  It  is  obvious  that  the  scavenging 
ports  must  not  t>e  uncovered  by  the  piston  until  the  pressure  of  the  hot 
gases  in  the  cylinder  has  fallen  below  the  pressure  of  the  scavenging 
air;  serious  scavenging-air  receiver  explosions  have  resulted  from  insuffi- 
cient attention  to  this  precaution.  At  full  load,  the  terminal  pressure 
in  a  Diesel  cylinder  is  about  40  pounds;  the  scavenging-air  pressure 
rarely  exceeds  6  pounds.  It  is  necessary,  therefore,  that  the  exhaust 
ports  be  uncovered  in  advance  of  the  scavenging  ports,  and  the  amount 
of  this  earlier  opening  is  usually  about  8  per  cent  of  the  piston  stroke. 

Uncovering  the  scavenging1  ports  after  the  exhaust  ports,  naturally 
involves  covering  the  exhaust  ports  after  the  scavenging  ports;  the  re- 
sult of  which  is  that,  at  the  time  the  upwards-traveling  piston  covers 
the  exhaust  ports — namely  at  about  20  per  cent  of  the  stroke — the  cylinder 
is  filled  with  air  at  very  little  above  atmospheric  pressure,  which  is  com- 
pressed during  the  remainder  of  the  stroke.  Thus  the  weight  of  air 
compressed,  by  this  system,  does  not  exceed  85  per  cent  of  the  weight 
of  a  cylinder  full  at  atmospheric  pressure. 

Moreover,  the  scavenging  by  this  method  is  imperfect,  and  there  is 
an  opportunity  for  burnt  gases  to  blow  back  into  the  cylinder  before  the 
exhaust  ports  are  closed;  the  cylinder,  therefore,  contains  somewhat 
impure  air.  In  very  small  engines  the  scavenging  may  be  improved  by 
providing  the  top  of  the  piston  with  a  projection  to  guide  the  stream  of 
scavenging  air  upwards;  but  in  Diesel  engines  of  even  very  moderate 
size  a  piston  of  this  form  would  not  last  many  days. 

The  net  result  of  the  foregoing  is  the  inability  to  perfectly  consume, 
in  an  engine  of  this  type,  the  full  quantity  of  fuel  which  could  be  con- 
sumed if  the  cylinder  contained  pure  air  in  an  amount  equal  to  the 
cylinder  full  at  atmospheric  pressure. 

The  Sulzer  scavenging  system  avoids  the  above  described  faults  in  a 
safe  and  simple  manner.  It  utilizes  port-scavenging;  but  employs  two 
tiers,  instead  of  only  one  tier  of  ports.  The  piston  uncovers  the  upper 


156 


PRINCIPLES  OP  CONSTRUCTION 


jJBwi 


tier  of  scavenging  ports  before,  and  the  lower  tier  after,  it  uncovers 
the  exhaust  ports,  but  the  communication  between  the  interior  of  the 
cylinder  and  the  scavenging-air  supply  or  receiver,  through  the  upper 
ports,  is  controlled  by  a  timed  and  mechanically  operated  valve,  which 


PRINCIPLES  OF  CONSTRUCTION 


157 


remains  closed  until  the  exhaust  ports  have  been  uncovered  long  enough 
to  reduce  the  pressure  of  the  gases  in  the  cylinder  to  nearly  atmospheric; 
after  which  tihis  valve  is  opened,  while  the  piston  uncovers  the  lower 
scavenging  ports;  a  rapid  and  thorough  purging  is  then  effected  with 
complete  safety  against  a  blow-back  into  the  scavenging  receiver. 

Upon  its  return  stroke,  the  piston  first  covers  the  lower  scavenging 
ports  and  then  the  exhaust  ports;  the  upper  scavenging  ports  and  their 
valve  remains  open,  enabling  the  scavenging  air  to  fill  the  cylinder  at  full 
scavenging  pressure  before  the  communication  is  shut  off  by  the  piston. 
Obviously  a  blow-back  of  exhaust  gases  into  the  cylinder  cannot  occur; 
furthermore,  the  double  tier  arrangement  and  proper  form  of  the  scav- 
enging ports  insure  a  clearing  out  of  such  thoroughness  that  substan- 
tially no  burnt  gases  remain  in  the  cylinder — analyses  have  shown  that 
this  residue  does  not  exceed  3  per  cent.  The  weight  of  air  compressed  is 
thus  substantially  100  per  cent  of  the  weight  of  a  cylinder  full  at  atmo- 
spheric pressure,  and  it  is  possible  to  perfectly  consume  the  full  quantity 
of  fuel. 

Incidentally,  the  effectively  directed  streams  of  scavenging  air  cool 
the  cylinder  more  evenly  than  is  possible  with  ordinary  port-scavenging. 

In  accompanying  illustration  of  cross-sectional  view  of  the  Carels  type 
of  scavenging  valve  it  will  be  noted  that  in  this  case  it  may  be  com- 
pared to  valves  of  similar  construction  on  four- 
cycle engines  used  for  exhaust  purpose.  The 
method  of  location  of  these  valves  on  Nord- 
berg  engines  in  the  cylinder  head  is  a  feature 
which  has  been  found  satisfactory  on  this  type 
of  construction.  The  advantage  gained  may  be 
summarized  in,  first,  added  strength  to  the 
'head  itself  and,  second,  establishing  more  uni- 
form cooling. 

The  importance  of  establishing  a  satisfac- 
tory scavenging  method  has  caused  manufac- 
turers to  adopt  a  double  system  of  scavenging. 
In  the  case  of  double-acting  two-cycle  engines 
in  some  types  a  scavenging  pump  for  each 
cylinder  was  found  necessary. 

In  most  marine  types  of  engines  the  valves 
are  actuated  by  levers,  the  cams  operated  by 
contact  from  the  cam  shaft.  The  arrangements 
of  providing  a  double  set  of  scavenging  valves, 
one  on  each  side  of  the  fuel  inlet  valve,  is  a 
feature  adopted  by  some  firms. 

The  principle  of  the  port  system,  as  in  the 
Cross-sectional  view  of  case  of  the  Busch-Sulzer,  for  its  larger  types 
Carels  type  of  scavenging   of  engines  owing  to  the  amount  of  air  neces- 
valve,  used  on  Nordberg   sary  in  performing  the  function  of  scavenging 
engine.  appears  to  be  the  future  method. 


158 


PRINCIPLES  OF  CONSTRUCTION 


METHODS    EMPLOYED    IN    REVERSING    MARINE    DIESEL    ENGINES 

Unlike  the  Diesel  engine  for  stationary  purpose,  operating  in  con- 
tinual one  way  direction,  the  problem  of  reversing  marine  engines  has 
been  given  a  great  deal  of  consideration  by  designers.  On  late  types 
many  new  methods  have  been  adopted  to  accomplish  the  reversing  of 
engines,  which  must  accurately  answer  the  immediate  requirement  of 
giving  its  motion  in  either  direction  for  maneuvering. 

Unlike  a  steam  engine,  following  uniform  laws  of  old-established 
principles,  the  setting  of  valves  require  the  most  intimate  knowledge 
of  problems  to  be  confronted  in  general  operation  of  Diesel  machinery. 

Mechanical  contrivances  imperative  to  establish  automatic  operation 
must  be  thoroughly  understood.  Again  the  varying  methods  on  different 
machines  as  will  be  observed  when  carefully  going  over  the  processes 
of  operation  on  the  different  types  of  engines  dealt  with  in  this  book, 
will  be  found  beneficial  in  studying  this  prime  mover. 

In  the  following  illustration  a  valve-setting  diagram  for  ahead  and 
astern  running  of  a  reversible  two-cycle  engine  is  shown. 


Valve  Setting  Diagram  /or  reversing  of  Two-cycle  Engine. 
(Starboard  to  Port) 


As  a  matter  of  fact,  in  the  operation  of  Internal  Combustion  Engines, 
in  particular  the  high  compression  type,  the  following  proceedings  have  to 
be  carried  out,  when  reversing  is  to  be  accomplished,  on  most  marine 
engines : 

(1)     The  valve  levers  have  to  be  lifted  off  the  cams  on  the  camshaft. 


PRINCIPLES  OF  CONSTRUCTION  159 

(2)  The  camshaft  has  to  be  moved  fore  and  aft  to  bring  the  astern 
cams  underneath  the  rollers  of  the  valve  levers,  after  which  the  levers 
must  be  dropped  down  again  fen  to  the  cams. 

(3)  Compressed  air  has  to  be  admitted  to  all  cylinders,  after  this, 
where  perhaps  the  engine  is  composed  of  six  cylinders,  two  have  to  be 
placed  on  fuel  and  four  on  air;   next,  two  on  air  and  four  on  fuel,  and 
finally  all  on  fuel. 

If  the  engine  is  running  when  the  order  is  given  for  it  to  stop,  the 
fuel  supply  must  be  immediately  lowered.  This  is  usually  accomplished 
by  mechanical  arrangement  of  a  hand-wheel  turned  to  the  stop  position, 
as  indicated  on  the  dial.  This  causes  a  partial  rotation  of  a  spindle, 
which  raises  or  lowers  the  rods.  These  are  attached  to  sleeves,  on 
which  the  levers  operating  the  fuel  valves  are  eccentrically  mounted. 
The  other  end  of  the  lever  on  the  fuel  valve  cam  is,  therefore,  raised 
from  the  cam  by  this  operation  and  is  only  brought  down  on  to  the 
cam  at  the  right  moment  by  the  movement  of  the  starting  wheel.  In 
other  words,  when  the  engine  is  in  the  stop  position  the  fuel  valves 
and  starting  air  valves  are  automatically  out  of  operation  until  the 
hand  wheel  is  moved. 

Assuming  the  engine  is  stopped  after  having  been  running  ahead, 
and  the  order  is  received  to  go  astern,  the  reversing  lever  is  moved  from 
the  back  position  to  the  front.  This  puts  compressed  air  on  the  motor 
(some  times  as  in  the  case  of  the  Vickers  types,  Servo  motors),  which 
by  means  of  a  rack  motion,  first  partially  rotates  the  horizontal  shaft 
which  lifts  the  exhaust  and  inlet  valve  levers  off  their  cams  through 
the  link,  then  causes  the  lever  to  move  fore  and  aft,  giving  thei  corre- 
sponding motion  to  the  camshaft,  after  which,  by  the  continued  rotation 
of  the  shaft  and  the  movement  of  the  link,  the  valve  levers  are  once 
more  brought  down  to  the  cams.  Only  'when  this  complete  movement 
has  been  effected  is  it  possible  to  move  the  starting  wheel. 

Immediately  the  cams  are  in  the  astern  position  this  starting  wheel 
is  rotated  by  hand  until  the  indicator  on  the  dial  shows  that  air  is  being 
supplied  to  all  cylinders  through  the  distributing  valves.  The  engine 
then  starts  up  on  air,  after  which,  the  starting  wheel  is  turned  to  the 
next  position  indicated  on  the  dial,  namely,  two  cylinders  on  fuel  and 
four  on  air.  This  is  accomplished  by  the  rotation  of  the  spindle  as  pre- 
viously mentioned,  allowing  the  fuel  valve  levers  to  come  down  on  their 
cams.  Further  rotation  of  the  starting  wheel  cuts  out  the  air  supply 
and  allows  four  of  the  six  cylinders  (taking  this  method  to  be  on  six 
cylinder  engines) ,  and  finally  all  of  them,  to  operate  on  fuel. 

It  should  be  mentioned  that  the  valve  levers  are  lifted  off  their 
cams  by  the  movement  of  the  manoeuvering  shaft,  owing  to  the  fact 
that  these  levers  are  usually  mounted  eccentrically  upon  the  shaf. 

The  reason  that  the  fuel  valve  levers  are  brought  down  on  to  their 
cams  in  pairs  as  described,  is  that  there  are  cams  in  this  particular 


160 


PRINCIPLES  OF  CONSTRUCTION 


case  on  the  shaft  which  lift  the  levers  at  the  time  required  for  putting 
into  action  the  respective  valves,  according  to  the  position  of  the  start- 
ing wheel. 

In  many  engines  hand-pumps  are  used,  operated  by  levers,  in  case 
it  is  desired  to  carry  out  the  reversal  by  hand  instead  of  by  com- 
pressed air. 

In  most  engines  individual  cylinders  can  be  cut  out  by  means  of 
hand-levers  if  the  requirement  necessitates  the  same. 


\W/- 


Valve  Setting  Diagram  for  Reversing  of  Two-cycle  Engine. 
(Port  to  Starboard) 


It  is  the  opinion  of  the  writers  that  the  large  marine  Diesel  engines 
will  more  and  more  resemble  each  other  and  that  certain  standards  in 
design  will  be  adopted  by  all  builders,  as  since  long  has  been  the  case 
with  the  reciprocating  steam  engine. 

The  tendency  shows  already  in  the  general  designs  of  most  modern 
engines.  It  will  be  noticed  that  with  the  increased  demand  for  larger 
types  of  Diesel  engines  the  gradual  uniformity  in  build  and  general 
design  are  identical.  It  is  true,  that  the  tendency  of  manufacturers  ad- 
hering to  either  the  two-cycle  or  the  four-cycle  type  leaves  a  gap  not 
to  be  found  in  steam  engine  construction,  'but  as  both  engines  of  late 
have  been  brought  to  a  high  stage  of  perfection,  manufacturers  in  the 
United  'States  as  well  as  in  Europe  will  find  it  convenient  to  establish 
standards  to  be  adopted  governing  existing  problems  in  Diesel  engine 
construction. 

In  most  engines  of  large  horse  power  capacity,   the  reversing  mo- 


PRINCIPLES  OF  CONSTRUCTION  161 

tions  are  carried  out  by  the  valve-rockers,  and  like  all  eccentric  move- 
ments the  action  is  very  peculiar,  yet  exceedingly  simple.  In  the  Werk- 
spoor  engine,  there  are  four  rockers  per  cylinder,  for  the  inlet,  exhaust, 
air-starting  and  fuel  valves  respectively.  Each  rocker  is  mounted  on  a 
diagonal-eccentric,  the  eccentric  being  secured  to  the  shaft  and  is  free 
to  move  in  the  hub  of  the  rocker.  To  shift  the  rocker-rollers  from  one 
cam  to  another  it  is  merely  necessary  to  rotate  the  rocker-shaft  180 
degrees.  In  the  neutral  position  at  90  degrees  the  rollers  are  clear  of 
the  cams.  The  turning  of  this  rocker-shaft  requires  very  little  effort, 
and  actually  can  be  done  by  hand.  But,  to  facilitate  the  operation,  a 
little  double-acting  air  engine  with  an  oil  cushion  is  provided  and  this 
reciprocates  a  ratchet  that  is  in  connection  to  a  ratchet-wheel  on  the 
rocker-shaft. 

It  will  be  realized,  that  when  the  valve-rocker  moves  from  the  ahead- 
cam  to  the  astern-cam  the  position  of  its  valve-tappet  also  changes,  and 
this  is  arranged  for  by  the  provision  of  a  double  head,  or  tappet,  with  an 
adjusting  screw  on  each.  The  setting  of  the  rocker-rollers  is  so  ar- 
ranged that  when  running  "ahead"  the  roller-face  is  square  on  the  cam, 
but  in  the  "astern"  position  the  face  of  the  roller  is  not  absolutely  square 
on  the  cam,  is  resting  at  a  slight  angle,  which  is  of  no  consequence 
because  the  wear  of  the  astern  position  is  exceedingly  slight,  partly 
owing  to  the  very  limited  periods  during  which  the  engine  runs  astern 
and  partly  because  of  the  large  size  of  the  roller. 


DESCRIPTION    OF    GOVERNOR   AND   GENERAL    ARRANGEMENT   OF 

CONNECTIONS  OF  ASPINALL'S  GOVERNOR   FOR 

DIESEL   ENGINES 

The  Governor  is  fitted  to  a  reciprocating  lever  worked  by  engine 
crosshead,  or  suitable  motion,  having  for  preference  an  angular  move- 
ment of  about  45  degrees,  and  making  about  80  double  strokes  per 
minute.  The  Governor  "A"  is  adjusted  to  act  about  5  per  cent,  above 
the  running  speed  of  the  engines.  When  the  pre-determined  speed  is 
reached,  the  large  weight  of  Governor  is  left  behind  on  the  downward 
stroke  of  the  special  Lever  "L"  the  bottom  pawl  on  Governor  carries 
Engaging  Lever  "B"  into  its  upper  position,  which  lifts  the  Suction 
Valve  on  Oil  Pump  off  its  seat  through  Rod  "J"  and  Levers  "D"  and 
"E."  When  this  action  takes  place  the  bulk  of  the  fuel  oil,  instead  of 
passing  through  the  Delivery  Valve  to  the  Cylinder,  is  returned  to  the 
Suction  Chamber,  and  the  engines  are  then  slowed  down.  The  amount 
to  which  the  Suction  Valve  is  lifted  off  its  seat  by  the  Governor  is  reg- 
ulated by  the  Screw  "R,"  which  is  set  so  that  a  small  quantity  of  Oil 
Fuel  will  pass  through  the  Delivery  Valve  to  the  Cylinder.  When  the 
speed  of  the  engines  has  moderated,  the  large  weight  of  Governor  drops 
into  its  lower  position,  and  top  pawl  depresses  Lever  "B,"  which  allows 
the  Suction  Valve  for  Fuel  Pump  to  come  on  its  seat;  the  full  supply  of 


162 


PRINCIPLES  OF  CONSTRUCTION 


ASPINAUS  WC,ttT,MAfttNg  TYPE  &0V£R.NOR 


r£RNAt  COMBUSTION  Oft 


Fig.  A.     Aspinalls  Marine  Governor  applied  to  Internal  Combustion 

Engines. 


PRINCIPLES  OF  CONSTRUCTION  163 

Oil  Fuel  is  then  discharged  through  the  Delivery  Valve  to  the  Cylinder, 
and  the  engines  regain  their  normal  speed.  The  Lever  "F,"  connected 
with  the  Hand  Gear,  is  fitted  with  a  Fork  End  which  works  outside  the 
Lever  "E"  of  Governor  Gear.  With  this  arrangement  the  Governor 
Gear,  or  Hand  Gear,  work  independently  of  each  other.  (Note:  The 
arrangement  of  connections  may  be  varied  in  numerous  ways,  providing 
the  principle  of  the  action  of  the  Governor  is  duly  considered. 


DETAILED  DESCRIPTION  OF  GOVERNOR 

The  Governor  consists  of  a  hinged  Weight  "W,"  operating  two  Pawls 
"PP,"  carried  on  a  frame,  which  is  bolted  to  a  Lever  "L,"  having  a 
suitable  reciprocating  motion.  When  the  revolutions  of  the  engines  are 
increased  by  about  5  per  cent  above  the  normal  running  speed  the  Weight 
"W"  is  left  behind  on  the  downward  stroke  of  the  Lever  "L,"  and  reverses 
the  position  of  the  Pawls  "PP,"  causing  bottom  one  to  engage  with  Lever 
"B,"  lifting  it  throughout  the  upward  stroke  of  Lever  "L,"  and  thereby 
Shuts  Off  the  fuel  supply  to  the  engines.  On  the  next  downward  stroke 
of  the  Lever  "L"  the  Detend  "Q"  is  lifted  by  coming  into  contact  with 
Lever  "B,"  liberating  the  Weight  "W,"  and  when  the  revolutions  of  the 
engines  have  moderated,  thei  WTeight  "W"  drops  into  its  lower  position 
and  again  reverses  the  position  of  the  Pawls  "PP" — the  top  one  now 
engages  with  the  Lever  "B,"  depressing  it  throughout  the  next  down- 
ward stroke  of  the  Lever  "L,"  and  thereby  Opens  Up  the  Oil  Fuel  supply 
to  the  engines  again. 

The  Emergency  Gear  only  comes  into  operation  in  the  event  of  the 
engines  approaching v  an  excessive  speed,  such  as  would  occur  in  the 
event  of  loss  of  propeller  or  the  breaking  of  a  shaft,  in  which  case 
the  Weight  "U"  is  left  behind  on  the  downward  stroke  of  the  Lever  "L" 
and  locks  the  Weight  "W"  in  the  Shutting-Off  position,  thereby  effect- 
ually Shutting  Off  the  Fuel  supply  to  the  engines.  To  release  the 
Emergency  Gear  from  locking  position  press  the  Weight  "W"  upwards 
from  the  underside,  when  the  Weight  "U"  will  fall  out  of  gear. 


INSTRUCTIONS  FOR  FIXING  GOVERNOR 

Bolt  the  Governor  on  the  side  of  the  Lever^  "L"  at  a  given  distance 
"F"  from  Fulcrum  to  Face  the  Weight  "W."  Place  Lever  "L"  at  Top  of 
its  stroke,  as  shown  in  dotted  lines  on  Fig.  2,  lift  the  Weight  "W"  into 
its  upper  position,  which  brings  the  Bottom  Pawl  out.  Then  file  out 
metal  from  end  of  Slot  in  Lever  "B"  until  the  engaging  end  of  Lever 
"B"  is  %-inch  above  Pawl,  with  end  of  Slot  hard  up  against  Stop  Pin 
"S."  Then  connect  up  gear  between  Lever  "B"  and  control  gear  at  fuel 
pump,  which  should  be  in  the  Shutting-Off  position  with  the  gear  adjusted 
so  that  engaging  end  of  Lever  "B"  rests  on  Bottom  Pawl.  Next  discon- 
nect gear  between  Lever  "B"  and  control  gear  at  fuel  pump  and  place 
Lever  "L"  at  Bottom  of  its  stroke;  lift  Detent  "Q,"  which  will  allow 


164 


PRINCIPLES  OF  CONSTRUCTION 


PRINCIPLES  OF  CONSTRUCTION  165 

Weight  "W"  to  drop  into  its  lower  position  and  bring  out  Top  Pawl. 
Then,  file  out  of  other  end  of  Slot  in  Lever  "B"  until  engaging  end  of 
Lever  "B"  is  %-inch  below  Top  Pawl  with  end  of  Slot  hard  up  against 
Stop  Pin  "S."  Again  connect  up  the  gear  between  Lever  "B,"  and  con- 
trol gear  at  fuel  pump,  with  Top  Pawl  resting  on  engaging  end  of  Lever 
"B"  when  the  control  gear,  if  correctly  adjusted,  should  be  in  the  Open- 
ing-Up  position. 

The  distance  "F"  is  fixed  by  the  makers  of  the  Governor  after  receiv- 
ing particulars  of  the  engines. 


INSTRUCTIONS    FOR    REGULATING    GOVERNOR 

To  make  the  Governor  more  sensitive,  i.  e.,  to  Shut  Off  at  a  less 
number  of  revolutions,  the  Regulating  Screw  "R"  on  Spring  Buffer  Ad- 
justment "V"  must  be  screwed  outwards.  To  make  the  Governor  less 
sensitive,  i.  e.,  to  Shut  Off  at  a  greater  number  of  revolutions,  the  Reg- 
ulating Screw  "R"  on  Spring  Buffer  Adjustment  "V"  must  be  screwed 
inwards. 

To  make  the  Emergency  Weight  "U"  later  in  its  action,  take  out  the 
Plug  "X"  and  insert  a  suitable  washer  inside  the  Box  behind  the  spiral 
spring. 


HINTS    FOR     KEEPING    GOVERNOR     IN    WORKING    ORDER. 

All  parts  of  the  Governor  should  be  kept  thoroughly  clean;  a  piece 
of  rag  and  paraffine  being  used  for  cleaning  purposes.  Cotton  waste 
should  on  no  account  be  used,  as  particles  of  same  are  liable  to  get  into 
working  parts  and  retard  the  free  working  of  the  Governor.  A  little 
mineral  or  sperm  oil  should  be  used  for  lubricating  purposes;  oils  of  a 
clogging  nature  -to  be  avoided. 

If  the  Governor  is  fixed  under  platform  gratings,  a  piece  of  canvas 
or  sheet  iron  should  be  attached  to  underside  of  grating  to  prevent  dirt 
falling  on  the  Governor.  The  Weight  "W"  should  be  tipped  upwards  by 
hand  once  a  day  to  ensure  the  Governor  and  Gear  being  kept  free  and  in 
working  order. 


MARINE     DIESEL    ENGINES    FOR    TWIN-SCREW    SHIPS. 

The  method  of  twin-screw  propulsion  appears  to  be  momentarily  far 
more  favored  than  the  single  screw  process.  Firms,  foremost  in  the  con- 
struction of  Diesel  machinery  claim  advantageis  in  favor  of  the  twin- 
screw  propulsion  as  against  the  single-screw  operation,  so  commonly 
found  on  steam-driven  ships.  Following  reasons  are  given  by  the  Bur- 
meister  &  Wain  Co. 

(1)  The  engines,  shaftings  and  propellers  are  lighter  than  those  of 
the  corresponding  engine  of  a  single-screw  vessel. 


166 


PRINCIPLES  OF  CONSTRUCTION 


PRINCIPLES  OF  CONSTRUCTION 


167 


(2)  The  engines  require  less  space  length-wise,  thus  the  engine  room 
becomes  shorter,  and  in  spite  of  this  there  is  ample  room  for  placing  the 
auxiliary  machinery,  partly  along  sides  of  the  ship  and  partly  between 
the  two  main  engines. 


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(3)  The  dimensions  of  the  different  parts  of  the  Diesel  engines  being 
reduced,  they  are  more  easy  to  handle,  and  as  the  whole  unit  is  adapted 
for  forced  lubrication,  by  which  all  inspection  of  the  working  parts,  while 
the  engine  is  running,  is  rendered  unnecessary,  if  only  the  pressure  of 
the  lubricating  oil  is  kept  constant,  the  attention  of  the  increased  number 
of  details  will  cause  no  difficulties  and  no  additional  labor  will  be  re- 
quired. 


168 


PRINCIPLES  OF  CONSTRUCTION 


Descriptive  View  of  Worthington  Solid  Injection  Two-Cycle  Diesel 
Engine    ( Exposed ) . 


PRINCIPLES  OF  CONSTRUCTION  169 

(4)  The  two  engines  working  independently  of  each  other  assure  a 
greater  reliability,  and  the  efficiency  of  the  two  propellers  on  higher  revo- 
lutions will  be  greater  than  that  of  a  single-screw  running  at  lower  revo- 
lutions. 

The  point  last  mentioned  is  one  of  the  most  essential  advantages  -and 
has  enabled  motor  vessels  to  carry  through  their  voyages  at  such  a  good 
mean  speed  even  in  bad  weather.  This  is  accounted  for  firstly  by  the  fact 
that  the  propelling  power  is  distributed  over  two  propellers  thereby  at- 
taining a  larger  thrust  pressure.  The  propellers  are  placed  well  clear  of 
the  ship's  sides,  thus  assuring  a  good  and  free  flow  to  the  propellers. 

In  bad  weather  these  small  propellers  do  not  readily  get  above  the 
surface  of  the  water.  Should  this  happen  a  better  propulsion  is  never- 
theless maintained  in  comparison  with  a  propeller  worked  by  a  steam  en- 
gine, on  account  of  the  following: 

The  Diesel  engine  is  furnished  with  a  governor,  which  as  soon  as  the 
propellers  rise  above  the  surface  of  the  water  and  the  revolutions  of  the 
engine  thereby  are  increased  by  afoout  10%  above  the  normal,  operates 
and  cuts  off  the  oil  supply  to  the  cylinders  and  keeps  the  engine  at  about 
normal  revolutions.  At  the  moment  the  propellers  again  enter  the  water 
and  the  revolutions  are  somewhat  reduced,  the  governor  acts  immedi- 
ately, adjusting  the  supply  of  fuel  oil  to  the  normal  quantity,  so  that  all 
the  cylinders  give  full  power  at  once.  This  is  not  the  case  with  an  ordi- 
nary marine  steam  engine.  Even  if  here  the  governor  cuts  off  at  once 
for  the  admission  of  steam,  as  soon  as  the  propeller  leaves  the  water,  the 
revolutions  of  the  steam  engine  will  nevertheless  be  increased  owing  to 
the  large  quantities  of  steam  still  remaining  in  the  receivers.  When  the 
propeller  again  enters  the  water,  the  governor  will  at  once  admit  the 
steam  to  the  high  pressure  cylinder,  but  the  engine  will  not  be  able  to 
attain  its  normal  power,  until  the  receivers  again  are  filled,  frequently 
the  steam  engine  will  be  practically  stopped  and  the  propeller  enters 
the  water.  In  heavy  weather  the  propulsion  is  therefore  better  of  Diesel- 
engined  vessels  than  of  steamers. 


DIESEL    HIGH    SPEED    ENGINES 

The  problem  of  high-speed  engines  for  auxiliary  purposes  enters  as 
one  of  vital  importance  in  modern  Diesel  power  plants.  In  many  cases 
the  gasoline  engine  has  been  found  to  perform  this  function  on  genera- 
tors, pumps,  compressors,  etc.,  in  a  most  satisfactory  manner. 

Of  late  high-speed  Diesel  engines  have  been  built  exceeding  400  revo- 
lutions per  minute.  As  a  matter  of  fact,  on  this  type  of  machinery  the 
fuel  consumption  has  been  found  so  low  that  its  competitor  in  high-speed 
engines  will  in  future  be  substituted  by  high-speed  full  Diesel  machinery. 

In  marine  engineering,  where  it  will  be  not  alone  a  matter  of  con- 
venience using  crude  oil  for  fuel  oil  solely,  in  operating  the  entire  unit, 
but  also  the  importance  of  space  allowance  must  be  considered.  In  saving 


170 


PRINCIPLES  OF  CONSTRUCTION 


PRINCIPLES  OF  CONSTRUCTION  171 

of  engine  room  space  the  advantage  is  with  high-speed  Diesel  machinery. 
In  weight  comparison  it  may  safely  be  said  that  Diesel  driven  engines  of 
high  speed  types  are  of  equal  proportion. 

The  general  upkeep  of  either  the  two-cycle  high-speed  or  these  fol- 
lowing the  four-cycle  principle  is  a  factor  which  may  be  worthy  of  men- 
tion. A  machine  of  this  kind  developed  by  the  Busch-Selzer  Company 
of  St.  Louis  of  four-cycle  construction  shows  wonderful  results.  In  this 
case  force-feed  lubrication  has  been  adopted  throughout.  The  vertical 
three-stage  compressor,  mounted  on  the  end  of  the  engine,  is  driven  off 
the  crankshaft  direct  from  the  engine. 


A  Small  Type  of  Nelesco,  Equipped  With  Paragon  Reverse  Gear.     This 
Type  Is  Ideal  for  Yachting,   Fishing   Crafts,  Etc. 

Firms  like  Krupp,  Augsburg-Nurnberg,  Steinbecker,  Vickers,  Werks- 
poor,  Burmeister-Wain,  Nordberg  Manufacturing  Co.,  have  produced  en- 
gines which  are  highly  commendable  for  use  in  auxiliary  operation  on 
marine  as  well  as  stationary  power  plants. 

It  is  but  natural  that  the  consumption  of  lubricating  oil  is  higher  on 
high-speed  than  on  low-speed  machinery.  The  amount  is  such  that  it  not 
seriously  effects  operating  expenses.  It  is  on  a  par  with  the  average  high- 
speed gas  engine  and  slightly  above  steam-driven  machines  of  equal  ca- 
pacities. It  may  be  figured  to  about  .012  to  .02  per  B.  H.  P.  .hour  as 
against  .01  to  0.12  Ib.  fuel  oil  consumption  is  in  this  case  about  from 
3l/2  to  7  per  cent  higher,  depending  upon  the  design. 


ECONOMY    IN     RIVER-FREIGHTER    OPERATION. 

Not  alone  is  the  Diesel  engine  a  dangerous  competitor  to  vessels  op- 
erated by  steam  power,  but  it  outclasses  any  other  prime-mover  in  econ- 
omy and  efficiency.  In  the  following  comparison  of  Diesel  vs.  distillate 
engine  on  the  river  freighter  "iSuison  City"  of  Oakland,  California,  the 
impartial  result  on  a  trial  trip  is  herewith  given: 

In  this  trial  trip  on  the  (Sacramento  River  after  two  65  h.  p.  twin- 
cylinder  12  in.  Atlas  distillate-engines  had  been  removed  and  two  55  h.  p. 


172 


PRINCIPLES  OF  CONSTRUCTION 


PRINCIPLES  OF  CONSTRUCTION 


173 


three-cylinder  8  in.  by  10 y2   in.  Atlas-Imperial  Diesel  engines  had  been 
installed  in  their  place,  following  was  the  result: 

Length  over  all 84  ft.  5  in. 

Breadth   _   23  ft.   5   in. 

Depth  _  _  6  ft.  5  in. 

Tons,  gross 142  tons 

Tons,  net 73  tons 

The  following  data  on  the  performance  of  the  boat  before  and  after 
having  this  change  of  machinery  made  is  exceedingly  interesting  as 
showing  in  black  and  white  why  the  Diesel  engine,  even  in  small  units, 
must  furnish  the  power  in  our  harbor  and  coastwise  fleets. 

Propeller  with  distillate  engines,  48  in.  diameter,  44  in.  in  pitch, 
232  R.  P.  M. 

Propeller  with  Diesel  engines,  44  in.  diameter,  38  in.  in  pitch,  340 
R.  P.  M. 

Speed  of  boat  with  distillate  engines,  8  miles  per  hour. 

Speed  of  boat  with  Diesel  engines,  9.2  miles  per  hour. 

Fuel  cost  with  distillate  engines  per  hour,  $3.22. 

Fuel  cost  with  Diesel  engines  per  hour,  $0.30. 

Actual  fuel  consumption  with  Diesel  engines  is  414  gals,  per  hour 
with  two  engines  and  2%  gals,  per  hour  with  one  engine.  Fuel  used  costs 
6  cents  per  gallon. 

This  is  but  one  of  many  conversions  from  distillate  to  Diesel  en- 
gines which  'the  non-availability  of  distillate  fuel  and  the  added  economy 
of  the  latter  type  engine  has  made  necessary  on  vessels  of  smaller  types, 
as  mentioned  herein. 

(From  Motorship,  December  1921.) 


The   Comparison   in  Space   Between   Sketch-Drawing  of  Vessel  Equipped 
With    Steam-Power.      (Fig.   A.) 


Sketch  Drawing    of   Vessel   Equipped   With   Diesel  Power    (Fig.   B)    Re- 
quires no  Explanation. 


174 


PRINCIPLES  OF  CONSTRUCTION 


COMPARISON    OF    EFFICIENCIES    OF    VARIOUS    TYPES    OF    POWER 

PLANTS 

HEAT  UNITS  IN  FUEL  CONSUMED  PER  BRAKE  HORSEPOWER 

HOUR. 


Simple  Non-Condensing 
Corliss   Engines 


Compound   Condensing 
Corliss  Engines 


Engine   Rating 

Engine   Rating 

Engine   Rating 

Engine   Rating 

200    I.H.P. 

800   I.H.P. 

100  I.H.P. 

400  I.H.P. 

Boiler    Pressure 

Boiler    Pressure 

Load  Per  Cent 

Boiler    Pressure 

Boiler    Pressure 

125   Ibs. 

180   Ibs. 

of    Rated 

100   Ibs. 

150   Ibs. 

Vacuum   2."i   In. 

Vacuum  27   In. 

H.   P. 

Steam  per  I.H.P. 

Steam  Per  I.H.P. 

Steam   per 

Steam  per 

Hour,    28    Ibs. 

Hour,    24   Ibs. 

I.H.P.     Hour, 

I.H.P.     Hour, 

n  ibs. 

13  Ibs. 

100 

52,500 

41,500 

25,500 

21,000 

75 

60,000 

47,500 

29,000 

23,500 

50 

79,000 

59,500 

36,500 

29,000 

25 

138,000 

99,000 

58,000 

45,000 

Triple   Expansion   Steam 


Steam  Turbines 


Engine   Rating 

Rating   5,000 

Engine   Rating 

1,000   I.H.P. 

Rating    500 

K.   W. 

400  I.H.P. 

Boiler    Pressure 

K.   W. 

Boiler    Pressure 

Boiler    Pressure 

200   Ibs. 

Boiler    Pressure 

200  Ibs. 

Load  Per  Cent 

150  Ibs. 

Superheat    100 

150   Ibs. 

Superheat    150 

of   Rated 

Vacuum    27    In. 

degrees    Fahr. 

Vacuum  26   In. 

degrees    Fahr. 

H.P. 

Steam   per 

Vacuum  27.5  In. 

Steam  per 

Vacuum  28   In. 

I.H.P.  Hour, 

Steam   per 

K.W.    Hour, 

Steam  per 

12.5  Ibs. 

I.H.P.    Hour 

21    Ibs. 

K.W.    Hour, 

10.5  Ibs. 

14   Ibs. 

100 

20,000 

17,500 

21,000 

15,000 

75 

22,500 

20,000 

23,500 

17,500 

50 

28,000 

24,500 

27,000 

20,500 

25 

43,000 

36,000 

36,000 

28,000 

DIESEL  ENGINES 

Load  Per  Cent                       Engine  Rating  Engine  Rating  Engine  Rating 

of  Rated  H.P.                           165  B.H.P.  520  B.H.P.  2,200  B.H.P. 

100   9,000  8,400  8,000 

75   9,500  8,900  8,500 

50 10,800  9,800  9,000 

25   15,400  13,000  12,000 

For  steam  plants  add  allowance  for  stand-by,  according  to  character 
of  load. 

To  obtain  equivalent  pounds  of  coal  divide  B.  T.  U.  by     12,500. 

To  obtain  equivalent  pounds  of  fuel  oil  divide  B.  T.  U.  by    18,800. 

To  obtain  equivalent  gallons  of  fuel  oil  divide  B.  T.  U.  by  143,000. 

Data  furnished  by  courtesy  of  Bush-Sulzer  Diesel  Engine  Co.,  St. 
Louis,  Mo. 


PRINCIPLES  OF  CONSTRUCTION 


175 


COMPARISON   IN  AVERAGE  FUEL  COST  OF  100  H.  P. 
Engines  driven   by  Gasoline,  Distillate  and   Engines  classified  as  Diesels. 

Gasoline 

Per   hour    2.50 

Per  day 25.00 

Per   week     ___  150.00 

Per  month    600.00 

Per  year 7200.00 

Note:  In  the  use  of  steam  it  may  safely  be  stated,  that  a  fuel  con- 
sumption of  300%  more  than  on  such  machinery  where  Diesel  power  is 
the  prime  mover,  will  be  required. 


Distillate 

Diesel 

1.70 

.42 

17.00 

4.20 

102.00 

25.20 

408.00 

100.00 

4896.00 

1209.60 

RECIPROCATING 
STEAM 


Comparison   Sketch  Between   Reciprocating    (Steam),    Turbine    (Steam), 

and  Diesel  Power.     Upper,  left,  Turbine;  Upper,  right,  Diesel; 

Lower  cut,  Reciprocating  Steam. 


CHAPTER  IX. 

AUXILIARY  MACHINERY  AND  ACCESSORIES 
OIL  PURIFICATION  ARRANGEMENTS 

A  very  important  point  which  should  be  given  careful  attention  by 
operating  engineers  in  the  operation  of  Diesel  machinery,  is  the  proper 
maintenance  of  its  oiling  and  lubrication  system. 

The  tendency  of  manufacturers,  in  the  design  of  bearings,  has  been 
towards  the  employment  of  lubricating  oils  at  much  higher  temperatures. 
Such  conditions  necessitates  the  use  of  oils  which  are  suitaMe  for  the  in- 
dividual requirements  and  which  must  be  given  such  attention  and  treat- 
ment as  will  minimize  trouble  in  the  practical  operation  of  the  unit.  Ex- 
perience indicates  that  the  lubricating  properties  of  oil  deteriorate  under 
the  influence  of  heat,  and  when  brought  into  intimate  contact  with  water 
and  air,  as  occurs  under  working  conditions.  These  various  actions  bring 
about  a  gradual  breaking  down  of  the  waxy  content  into  a  coagulate  or 
sludge  of  a  brownish  color,  insoluble  at  ordinary  temperatures  in  the  re- 
maining hydro-carbons,  which  are  the  vehicles  of  the  waxy  or  lubricating 
agents  in  solution  in  the  oil.  This  sludge,  with  its  precipitates,  if  not 
removed,  adheres  to  the  piping  of  the  oiling  system  and  often  obstructs 
the  flow  of  oil. 

The  quality  of  the  water  which  accidentally  comes  in  contact  with 
the  oil,  due  to  leakage  or  sweating  of  the  pipes,  affects  very  materially 
the  formation  of  sludge.  Acids  accelerate  this  action,  and  alkalies  aid 
in  emulsifying  the  oil.  The  design  of  modern  Diesels  provide  for  a  stor- 
age of  oil  directly  in  conjunction  with  the  main  engine,  with  pumping, 
circulating  and  cooling  systems  which  are  independent  in  operation.  Such 
arrangements  ordinarily  provide  for  relatively  limited  capacities  of  the 
oiling  system  so  that  it  is  forced  through  a  rapid;  cycle  of  operation.  This, 
in  connection  with  high  bearing  pressures  abnormal  temperatures,  tends 
very  rapidly  to  deteriorate  the  oil,  which  is  not  given  sufficient  time  to 
settle,  clarify  and  purify.  The  operating  practice  today  consists  of  re^ 
moving  all  the  oil  after  a  certain  time  in  service  and  replacing  it  with  a 
new  batch,  the  used  oil  being  passed  through  various  types  of  purifying 
and  filtering  equipment,  and  then  stored  for  future  use. 

Oil  should  be  selected  with  careful  regard  to  requirements  and  con- 
ditions of  "service.  Viscosity  should  be  referred  not  to  the  conventional 
standard  of  100  degrees  Fahrenheit  but  to  the  actual  temperature  at 
which  it  will  be  used,  as  there  is  an  appreciable  variation  in  the  viscosity 
of  all  oils,  depending  on  their  base  and  blending,  with  changes  of  temp- 
erature. The  specific  gravity  of  the  oil,  its  emulsifying  tendency  when 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


177 


mixed  with  water,  or  frothing  when  churned  with  air — these  actions  vary- 
ing with  the  temperature  of  the  oil— and,  also,  to  a  certain  extent,  the 
flash  point,  are  all  factors  which  have  an  important  bearing  on  the  life 
and  service  qualities  of  the  oil.  They  are  items  which  should  be  regarded 
as  of  prime  importance  in  the  selection  of  the  proper  grade  of  oil  in  the 
case.  The  oil  in  service  should  be  tested  at  frequent  intervals  because  its 
viscosity  and  specific  gravity  and  other  physical  'properties  change  very 
materially  with  use  and  age. 


Exposed  View  of  Burt  Oil  Filter 


The  proximity  of  the  oil  tank  to  the  engine  arrangements  thereto  are 
matters  which  require  serious  consideration.  The  oil  tank  and  connec- 
tions should  be  so  designed  as  to  prevent,  as  far  as  possible,  the  trans- 
mission of  any  heat  from  the  engine  to  the  oil. 

The  purification  of  the  oil  is,  in  general,  carried  out  by  one  of  two 
methods — the  continuous  system  and  the  batch  system.  In  the  first 


178  AUXILIARY  MACHINERY  AND  ACCESSORIES 

method  the  relief  valve  on  the  oil  system  of  the  engine  is  made  use  of  to 
by-pass  a  portion  of  the  oil  continuously  into  a  tank  from  which  it  is  fed 
by  gravity  into  the  oil  purifying  equipment  and  then  back  into  the  en- 
gine. This  acts  as  a  loop  in  the  oil  system  and  keeps  the  oil  constantly 
in  good  operating  condition. 

In  the  batch  system  the  engine  reservoir  is  completely  drained  at 
regular  intervals  into  a  tank  and  a  fresh  supply  of  oil  is  replaced.  The 
used  oil  is  then  purified  and  stored  for  future  service. 

In  operating  large  sized  Diesels,  it  is  important  to  cool  the  lubricat- 
ing oil  used  in  bearings,  reduction  gears,  etc.,  in  order  that  a  given  quan- 
tity of  oil  can  be  used  over  and  over  again  and  that  the  oil  supplied  to 
the  bearings  will  be  of  correct  temperature  to  maintain  an  oil  film  of 
proper  viscosity  between  the  bearing  surfaces.  The  Multiwhirl  Cooler, 
manufactured  by  the  Griscom-Russell  Company,  most  efficiently  performs 
this  service.  The  oil  is  pumped  through  the  shell  and  the  cooling  water 
through  the  tubes. 


Burt  Oil  Filter,  Full  View 

The  Multiwhirl  Cooler  is  designed  to  accomplish  the  heat  exchange 
between  any  two  liquids,  one  or  both  of  which  may  be  water;  the  con- 
densing and  subcooling  of  any  vapor  or  any  similar  service.  In  actual 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


179 


practice  it  has  proven  to  be  an  indispensable  equipment  in  such  plants 
where  Diesel  power  is  used.  The  advantages  of  this  oil  cooler  may  be 
summarized  in  following: 


Multiwhirl  Oil  Cooler — Exposed  View 

1.  Helical  baffle — long  smooth  oil  path — minimum   pressure   drop. 

2.  Tube  bundle  removable,  facilitating  inspection  and  cleaning. 

3.  Tubes  expanded  into  tube  plates;  no  sweated  joints. 

4.  Floating  head  construction;   no  expansion  strains  on  tube  joints. 

5.  Outside   packed   head;    this   construction   eliminates   any   possible 
leakage  of  water  into  oil  through  faulty  packing. 

6.  Compactness  of  unit;   this  is  permitted  by  the  high  rate  of  heat 
transfer  secured  in  the  Multiwhirl  Cooler. 

7.  Installation  in   any   position;    the  Multiwhirl  Cooler  may  be  in- 
stalled in  any  position  with  equal  efficiency  if  liquids    (not  vapor)   are 
being  handled. 


Griscom-RustelVs  "G-R*'  Instantaneous  Heater 


180 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


To  insure  proper  operation  of  valves,  such  as  fuel-inlet  valve,  etc.,  it 
is  imperative  that  certain  grades  of  oil,  in  particular  those  of  low  viscos- 
ity, be  heated.  In  accompanying  illustration  of  the  Reilly  Oil  heater  a 
good  view  is  allowed  on  its  interior  construction.  The  oil  is  circulated 
through  the  coils  and  is  heated  by  high  pressure  of  steam  application 
passing  on  the  interior  of  the  shell. 

Internal  joints  or  flanges  are  to  be  avoided  in  oil  heater  construction 
to  prevent  leakage  of  oil  into  steam  space  of  heater.  Such  oil  would  event- 
ually reach  the  engine  and  owing  to  the  fact  that  water  in  oil  has  a  ten- 
dency to  restrict  the  efficiency  in  power  production  it  would  give  addi- 
tional loss  in  generating. 

Water  in  lubricating  oil  should  be  eliminated  as  much  as  possible. 
It  will  create  heat  and  will  be  found  detrimental  in  general  purpose  of 
cooling. 

To  engineers  of  steam  plants,  where  oil  is  used  on  boilers,  the  neces- 
sity for  equipment  in  oil  purification,  pre-heating  of  oil  or  cooling  on  tur- 
bine-driven machinery  is  imperative.  In  following  illustrations  a  few 
apparatus  are  shown  adapted  today  in  plants  where  Diesel  power  is  used. 


OVERHEAD  OIL 
STORAGE 


OVE-RFLOVX/    FROM   ENGINE 


The  Equipment  of  De  Laval's  Oil  Separators  Assures  an  Excellent 
Method  of  Oil  Purification 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


181 


In  figure  (a)  the  illustration  shows  the  Wheeler  type  of  pre-heating 
of  oil.  It  will  be  noticed  that  this  arrangement  consists  of  essentially  an 
enclosed  cylindrical  vessel.  iSmall  tubes  directing  steam  through  it  which 
causes  the  heating  of  oil  to  be  accomplished  by  coming  in  contact  with 
the  surrounding  oil. 


frtn 


.0. 


Figure  (b)  shows  the  type  of  the  Elliott  Company  of  Pittsburgh,  Pa., 
known  as  the  Welderon  Receiver  Separator.  Its  function  is  to  separate 
impurities  which  may  cause  the  clogging  up  of  fuel  valves  and  the  piping 


182 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


system.  The  Welderon  Receivers  are  of  standard  construction.  The  oil 
and  entralnment  are  prevented  from  passing  into  the  outlet  by  baffles 
consisting  of  a  double  row  of  V-shaped  plates.  The  separator  is  fitted 
with  a  manhole  through  which  a  workman  can  enter  the  separator  and 
clean  the  baffles  in  place. 

To  be  efficient  in  the  removal  of  sediment  from  oil  it  is  essential  that 
the  baffle  plates  in  an  oil  separator  be  cleaned  at  frequent  intervals  to 
prevent  their  becoming  gummed.  The  flanges  are  threaded,  then  welded 
to  the  ends  of  the  through-pipe  by  a  special  process  and  form  the  nozzles 
of  the  separators.  The  body  of  the  receiver  is  also  welded  to  the  through- 
pipe,  which  makes  an  absolutely  tight  joint.  All  other  joints  and  seams 
are  riveted,  but  inasmuch  as  the  through-pipe  relieves  the  receiver  of  all 
strains,  due  to  vibration  in  the  pipe  line  or  to  contraction  and  expansion 
due  to  change  in  temperature,  the  riveted  construction  can  safely  be  used. 


Fig. 


(&).    Welderon  Receiver 
Separator 


Reilly  Oil  Heater- 
Exposed  View 


The  illustration  in  figure  (d)  represents  the  "Bundy"  Oil  Separator, 
manufactured  by  the  Griscom-Russell  Company,  Massilon,  Ohio. 

Instead  of  a  single  separating  plate  the  Bundy  Separator  has  a  num- 
ber of  such  plates,  thereby  insuring  that  any  oil  which  passes  by  the  first 
or  second  plate  will  be  caught  by  the  plates  which  follow.  These  plates 
are  of  the  grid  type,  the  grids  being  so  constructed  that  the  columns  of 
adjacent  grids  are  staggered. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


183 


The  surfaces  of  baffle  plates  used  in  oil  separators  are  usually  left 
unfinished  as  the  oil  will  cling  to  this  rough  surface  more  readily  than 
to  a  finished  surface.  If  a  separator  actually  separates,  some  portion  of 
the  constant  stream  of  oil  passing  over  the  separating  surfaces  will  ad- 
here and  bake  on,  thus  gradually  coating  the  surfaces  and  impairing  the 
efficiency  of  the  separator.  This  result  accompanies  real  separation  in 
any  type  of  separator.  Cleaning  is  therefore  necessary  if  the  efficiency 
of  the  separator  is  to  be  maintained.  In  order  to  permit  the  cleaning  of 
the  Bundy  plates,  a  door  in  either  the  side  or  top  of  the  main  casting  per- 
mits their  easy  removal  as  each  of  these  plates  is  a  separate  casting  and 
they  are  not  attached  in  any  way  to  each  other  or  to  the  main  separator 
casting. 


Fig.   (C) 

Stratton  Oil   Separator 
Horizontal   Type    (Exposed) 


Fig.   (D) 
Griscom-RusseWs 
"Bundy"  Oil  Separator 


The  separator  plates  should  be  thoroughly  boiled  for  about  6  to  12 
hours  in  a  strong  solution  of  potash,  or  soda  and  water.  Their  cleanliness 
will  be  detected  by  rust  appearing  on  the  surface  when  dry.  After  clean- 
ing, the  plates  can  be  replaced  in  the  separator  with  their  rough  cast 


184 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


Hoppes  Mfg.  Co.'s  Class  "R"  Oil  Heaters,  Showing  Multi-Trough 
Shape  I  Pan 


Class  ".R"  Oil  Heater — Front  End  Exposed 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


185 


iron  separating  surface  restored  to  their  original  condition.  The  best  way 
to  determine  just  when  the  cleaning  should  be  done  is  by  trial  and  obser- 
vation. On  old  work,  where  the  piping  has  become  foul  and  coated  through, 
long  usage,  it  is  reasonable  to  suppose  that  the  Bundy  separator  will  re- 
quire closer  watching  than  where  new  piping  is  used. 


Fig.    (e).    A   "(7L"  Oil  Separator 

In  the  illustration  (f)  of  the  multiscreen  Filter,  a  re-design  of  the 
well-known  Reilley  Multiscreen  Filter  and  Grease  Extractor  is  shown. 
This  installation  is  adapted  for  ships  on  over-seas  voyages.  In  particular 
where  steam  is  used  in  conjunction  with  Diesel  power. 


Fig-  (/)•     Griscom  Russell's  "G-R"  Multiscreen  Filter 


186 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


HELPFUL    HINTS    ON    LUBRICATION    AND    LUBRICATING    OIL 

If  the  oil  supplied  to  a  bearing  is  relatively  cold,  the  turbulence  is 
not  vigorous,  and  consequently  a  particle  of  oil  that  is  in  contact  with 
the  bearing  and  that  has  absorbed  its  share  of  the  heat,  does  not  move 
away  fast  enough  and  therefore  is  not  rapidly  replaced  by  another 
colder  particle  of  oil.  The  result  is  that  the  greater  part  of  the  cir- 
culating oil  during  its  travel  through  the  bearing  does  not  come  into 
contact  with  the,  metal  surfaces  but  passes  along  without  absorbing 
any  heat  Under  these  conditions,  the  bearing  becomes  heated  to  a 
point  where  the  temperature  difference  between  it  and  the  oil  film  in 
direct  contact  is  great  enough  to  transfer  the  heat  by  conduction  from 
the  bearing  to  the  oil  film.  This  comparatively  small  portion  of  hot 
oil  intermixes  with  the  remaining  larger  quantity  of  cold  oil,  estab- 
lishing at  the  outlet  of  the  bearing  a  low  oil  temperature  which  by 
no  means  indicates  the  temperature  of  the  bearing  itself. 


Oil  Cooling  and  Lubricating  System  for  Internal  Combustion  Engines  by 
Scfiutte  &  Koerting's  Method 

The  temperature  of  the  oil  may  be  surprisingly  low,  whereas  the 
temperature  of  the  bearing  itself  may  have  reached  the  allowable  maxi- 
mum. The  bearing  is  kept  cool,  not  by  establishing  a  low  outlet  oil  tem- 
perature, but  by  bringing  into  contact  with  the  surfaces  of  the  bearing 
as  many  particles  of  oil  per  unit  of  time  as  possible.  The  best  practice 
is  to  circulate  the  oil  energetically  and  to  recool  it  to  a  temperature  below 
the  normal  operating  temperature  of  the  bearing.  According  to  tests 
conducted  by  the  General  Electric  Company,  this  bearing  temperature 
is  about  160°  Fahrenheit. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


187 


In  the  illustration  of  the  Schutte  &  Koerting  Oil  Circuit  an  ideal 
System  of  proper  cooling  is  shown.  It  is  a  mistake  to  refer  the  outlet 
temperature  of  the  oil  to  the  outlet  temperature  of  the  cooling1  water. 
The  particular  oil  temperature  at  which  the  Diesel  engine  operates  most 
efficiently  should  be  maintained  irrespective  of  cooling  water  tempera- 
ture. The  latter  can  be  regulated  at  will  by  controlling  the  amount  of 
water  passing  through  the  cooler. 

In  a  test  on  a  standard  No.  7  cooler,  in  which  60  gallons  of  heavy 
Texaco  Ursa  oil  were  to  be  cooled  per  minute  with  160  gallons  of  cooling 
water  per  minute,  the  results  given  in  the  following  table  were  obtained. 


Water  Outlet 


Oil  Inlet 


Oil  Outlet 
To  Bearings 


Water  Inlet 


TABLE  OF  TEST  OF  No.  7  SHUTTE 
KOERTING  COOLER 


fas' 

I  ,- 


85 
70 
60 
50 
40 


156 
140 
128 
116 
104 


l*fc 

118 

103 

93 

83 

73 


Bid 

°Q-S 
*-•§ 

fl 

Q  •_,  cd 

g'gfo 

38 
37 
35 
33 
31 


Sectional  Elevation  of  Oil  Cooler  of 
the  Schutte  &  Koerting  type,  for 
Re-cooling  Lubricating  Oil  and  Cool- 
ing Oil  from  Diesel  Engine  Pistons 
and  Bearings. 


In  all  instances,  the  difference  between  the  water-inlet  and  oil- 
outlet  temperatures  was  33°  F.  Furthermore,  the  temperature  drop  of 
the  oil  decreased  with  a  decrease  in  the  initial  oil  temperature.  This 
is  primarily  due  to  the  fact  that  as  the  temperature  of  the  oil  dimin- 
ishes, the  oil  becomes  thicker  and  more  viscous,  and  its  movement  along 
the  cooling  surfaces  sluggish.  A  more  or  less  stagnant  layer  or  film 
of  oil  that  forms  also  retards  the  cooling  materially. 

A  large  quantity  of  oil  circulating  at  a  small  temperature  drop 
has  been  found  to  give  better  results  than  a  small  amount  of  oil  at  a 
large  temperature  drop.  The  oil  should  not  be  passed  through  the  bear- 
ings at  too  low  a  temperature,  since  cold  oil,  because  of  its  greater  vis- 


188 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


cosity  does  not  absorb  the  heat  of  a  bearing  as  well  as  oil  at  a  higher 
temperature.  The  Schutte  &  Koerting  Company  recommends  for  sta- 
tionary service  an  oil  temperature  drop  of  30°  P.,  namely,  from  150  to 
120°  F.,  since  from  the  experience  of  most  engine  builders,  this  range 
gives  the  best  operating  results.  Under  these  conditions  a  high  rate 
of  oil  flow  in  the  (bearings  is  provided,  as  well  as  a  thin  oil  film  that  in- 
sures a  vigorous  movement  and  rapid  efficient  absorption  of  heat  in 
the  bearings. 


Table,   Showing   Variation   of  Specific    Heat   of  Texaco 

Temp-e  nature. 


Ursa   Oil    With 


Temperature  of  Oil  Degree 
Fahrenheit. 
100 
120 
140 
160 
180 
200 
220 
240 
260 


Specific  Heat  of  Oil  B.  T.  U. 
per  Ib.  per  Degree  Fahr. 
0.437 
0.450 
0.462 
0.474 
0.486 
0.497 
0.508 
0.518 
0.527 


-Oil  Inlet 


Dram- 
Oil  Ouflet 

Sectional  Elevation  of  Lubricating  Oil  Filter  for  Diesel  Engines 


AUXILIARY  MACHINERY  AND  ACCESSORIES  189 

If  the  temperature  of  the  oil  entering  the  cooler  is  comparatively 
low,  the  cooler  will  necessarily  be  of  larger  dimensions  to  accommodate 
the  larger  quantity  .of  water  necessary  to  absorb  the  same  amount  of 
heat. 

The  oil  best  suited  for  Diesel  engine  lubrication  is  one  that  will 
withstand  contamination  with  impurities  under  the  conditions  of  most 
severe  service,— high  surface  speed,  rapid  circulation  of  oil,  presence 
of  water,  etc.  With  poor  grades  of  oil,  the  lubrication  is  inefficient, 
and  due  to  the  heat  generated,  bearing  temperatures  are  high,  the  oil 
is  oxidized,  and  its  life  limited  a  few  months. 

Excessive  oil  temperatures  are  sometimes  due  to  the  proximity  of  the 
oil  drain  tank  to  the  close  distance  of  engine.  Frequently  the  lubricat- 
ing oil  contains  entrained  particles  of  air  in  the  form  of  bubbles.  When 
the  circulation  is  rapid,  these  bubbles  burst  and  scatter  the  oil  in  fine 
sprays  or  vapor. 


o 
Schutte  &  Koerting's  Duplex  Oil  Strainer 

This  vapor  must  be  removed  from  the  bearing  housing  since  it  is 
likely,  where  in  case  of  engine  being  used  for  electrical  generation 
purposes,  to  creep  into  the  electric  generator,  where  it  can  cause  trouble 
For  this  purpose  the  oil  pipe  is  made  sufficiently  large;  otherwise  an 
additional  pipe  is  used,  venting  the  oil  reservoir  of  the  bearings  at  a 
higher  level  than  the  original  return  pipe  from  the  bearing  housing. 
Foaming  occurs  whenever  large  quantities  of  fresh  oil  are  added  ,to 
the  lubricating  system.  This,  however,  will  disappear  after  a  few 
hours  operation.  Should  it  persist,  air  is  probably  'being  sucked  into  the 
system  through  the  oil  pump.  All  air  leaks  should  be  eliminated  as 
quickly  as  possible. 


190  AUXILIARY  MACHINERY  AND  ACCESSORIES 

Solid  impurities,  such  as  particles  of  dust  and  dirt,  iron  oxide, 
etc.,  contaminate,  and  break  down  some  grades  of  oil  quickly.  Such 
oil  becomes  dark  in  color,  its  viscosity  is  high,  and  it  forms  a  sludge  that 
is  deposited  in  the  system,  usually  in  the  oil  cooler.  If,  furthermore, 
a  slight  trace  of  water  is  present,  the  oil  will  emulsify  considerably. 

In  instances  where  a  new  engine  is  started  up  for  the  first  time, 
there  will  always  be  in  the  lubricating  oil  particles  of  core  sand,  cotton 
waste,  scale,  etc.  Therefore,  after  the  engine  has  been  in  operation  for 
two  or  three  weeks,  the  oil  should  be  removed,  put  into  a  settling  tank, 
where  the  foreign  substances  will  deposite  at  the  bottom,  and  then  the 
good  oil  separated  off  from  the  top.  This  oil  can  be  subsequently  used  as 
make-up  oil. 

If  it  is  found  that  the  percentage  of  impurities  is  large,  the  oil 
should  first  be  heated,  separated  as  before,  and  then  run  through  a  filter 
before  being  introduced  into  the  lubricating  system.  A  more  definite 
and  positive  means  of  removing  solid  impurities  and  foreign  substances 
from  the  oil  is  provided  by  the  Duplex  Oil  strainer  of  which  accompany- 
ing illustration  gives  a  view. 

The  Duplex  Oil  Strainer  removes,  dirt,  sediment,  and  any  foreign 
material  that  has  accidentally  gotten  into  the  oil.  It  is  of  sufficient 
capacity  so  that  one  side  may  be  cut  out  for  cleaning  purposes  with- 
out interrupting  the  flow  of  oil  through  the  other  side,  that  is,  one  side 
of  the  strainer  can  be  cleaned  while  the  apparatus  is  running  under  full 
power.  It  is  operated  with  a  single  lever.  It  has  a  free  area  through 
the  straining  screens  that  permits  of  long  usuage  without  causing  the 
system  to  become  choked  and  clogged.  Sometimes  the  strainer  is  by- 
passed,— the  by-pass  being  provided  with  a  relief  valve  so  adjusted  that 
it  opens  when  a  fixed  differential  pressure  occurs  across  the  strainer. 
In  this  way  the  oil  flow  is  not  interrupted;  but  an  alarm  must  be  pro- 
vided to  indicate  when  the  valve  opens,  otherwise  the  clogged  strainer  will 
go  unnoticed. 

When  water  is  present,  the  result  is  an  emulsification  of  the  oil, 
With  large  quantities  of  water,  the  mixture  assumes  a  dark  yellow  color. 
If  a  sample  of  the  mixture  is  removed,  and  heated  in  a  test  tube,  it 
will  separate  out  into  oil  at  the  top,  milky  water  in  the  center,  and  a 
slimy  sludge  at  the  bottom  of  the  tube.  The  oil  is\  darker  in  color,  and 
somewhat  heavier  than  the  original  oil.  It  also  has  a  strong  character- 
istic odor. 

Water  is  the  cause  of  considerable  trouble,  since  in  appreciable 
quantities,  it  forms  a  sludge  that  clogs  up  the  passages  of  the  closed 
lubricating  system,  and  causes  the  temperature  of  the  circulating  water 
to  rise.  This  condition  is  usually  an  indication  that  insufficient  oil 
is  'brought  to  the  -bearings  for  cooling  purposes.  Frequently  the  engine 
must  be  shut  down  in  order  to  cleanse  the  system  thoroughly. 

When  water  leakage  is  unavoidable,  it  is  good  practice  to  put  a 
water  drain  into  the  bottom  of  the  drain  tank.  This  water  drain  should 
be  opened  once  in  every  24  hours,  so  that  any  water  accumulating  in  the 


AUXILIARY  MACHINERY  AND  ACCESSORIES  191 

system  can  be  withdrawn.  The  drain  cock  should  be  left  open  until  clear 
oil  appears.  It  is  also  advisable  to  open  the  drain  cock  before  starting 
the  engine.  The  suction  of  the  oil  pump  in  the  drain  tank  should  be  at 
least  two  to  four  inches  above  the  bottom  of  the  tank,  so  that  any  water 
which  may  have  separated  out  will  not  be  mixed  with  the  oil,  and  passed 
into  the  lubricating  system.  In  some  engine  rooms  the  usual  procedure  is 
to  remove  each  day  from  the  bottom  of  the  oil  tank  three  to  six  gallons 
of  oil.  This  is  heated  in  a  separating  tank,  and  later  filtered. 

It  is  advantageous  to  have  a  large  quantity  of  oil  in  circulation, 
with  large  oil  tanks  in  which  the  oil  has  time  to  rest  and  to  separate 
from  the  air,  water,  dirt  and  other  impurities  collected  in  the  system. 
There  is  always  more  or  less  air  in  the  circulating  oil.  At  about  180°  F., 
the  air  oxidizes  the  oil,  causing  it  to  assume  a  dark  color.  Carbon  is  de- 
posited and  frequently  chokes  up  the  oil  inlet  to  the  bearings,  and  causes 
the  oil  in  the  governing  gear  to  stick.  In  an  efficient  oiling  system  in 
which  there  is  no  waste  or  leakage  of  the  oil,  and  little  or  no  water,  the 
amount  of  make-up  to  be  added  every  week  is  very  small. 

Where  poor  grades  of  oil  are  used,  the  addition  of  new  oil  throws 
down  a  dark  deposit  throughout  the  entire  system.  This  is  particularly 
true  with  thei  heavier  grades  of  oil.  It  always  pays  to  use  the  proper 
high  grade  oils,  since  these  separate  quickly  from  impurities.  They  re- 
duce friction  to  a  minimum,  prevent  high  bearing  temperatures,  and  in- 
sure correct  lubrication  and  efficient  operation. 


RECOOLING  JACKET  WATER  OF  INTERNAL  COMBUSTION  ENGINES 

On  board  ships  or  in  plants  where  the  supply  of  fresh  water  for  cool- 
ing the  jackets  of  internal  combustion  engines  is  insufficient,  it  is  neces- 
sary to  use  the  same  clean  jacket  water  over  and  over  again,  and  for  this 
reason,  to  recool  water. 

This  can  be  done  to  advantage  in  the  water  cooler,  wherein  the  same 
principles  of  construction  are  employed  as  in  the  oil  cooler,  as  shown  in 
the  illustration  of  the  same,  and  the  same  exceptionally  high  heat  trans- 
fer, low  weight  and  small  space  requirements  are  obtained. 

Since  there  is  no  necessity  of  replenishing  the  jacket  water,  the  same 
water  is  used  over  and  over  again.  Thus,  due  to  the  continual  circula- 
tion, the  possibility  that  any  sediment  in  the  water  will  settle  in  the 
passes  of  the  cooling  packet  is  reduced  to  a  minimum,  and  cleaning  of  the 
jackets  is  unnecessary.  All  clogging  of  the  passes  is  avoided,  as  are 
strains  and  cracked  cylinders  caused  by  uneven  distribution  of  heat. 

By  using  a  recooler,  the  cost  of  fresh  water  is  reduced  or  entirely 
eliminated.  Furthermore,  the  heat  coming  from  the  heater  can  be  used 
to  advantage  in  many  ways,  increasing  materially  the  economy  of  the  en- 
gine plant.  The  cooling  water  in  the  cooler  must  be  capable  of  carrying 
off  from  an  ordinary  commercial  or  even  a  naval  type  of  Diesel  engine  an 
amount  of  heat  (including  that  abstratced  from  the  lubricating  oil),  equal 
to  about  35  per  cent  of  the  total  heat  in  the  fuel  consumed. 


192  AUXILIARY  MACHINERY  AND  ACCESSORIES 

For  example:  An  engine  consuming  per  B.  H.  P.  hr.  (horsepower 
hour  actually  delivered  at  the  coupling  end  of  the  crank  shaft),  0.40  Ib. 
of  fuel  oil  of  18,000  B.  T.  U.  per  Ib.  or  7200  B.  T.  U.  per  B.  H.  P.  hr.,  will 
require  sufficient  cooling  water  to  carry  off  2520  B.  T.  U.  per  B.  H.  P. 
hour. 

If  the  water  has  a  temperature  of  70°  Fahrenheit,  and  the  discharge 
temperature  is  limited  to  100°  Fahr.,  the  quantity  of  cooling  water  re- 
quired will  be  84  Ibs.  or  about  10  gallons  per  hour  per  B.  H.  P.  Under 
these  conditions  the  water  pressure  will  be  less  than  30  Ibs.  per  square 
inch. 

If  the  total  heat  of  the  engine  amounts  to  about  775,000  B.  T.  U.  per 
hour,  about  260,000  B.  T.  U.  per  hour  would  be  transformed  into  mechan- 
ical work.  This  means  a  heat  loss  (total  heat  loss  =  total  heat  available 
-  heat  transformed  into  mechanical  work)  of  775,000  —  260,000,  or  515,- 
000  B.  T.  U.  Of  this  amount,  about  one-half  must  be  absorbed  by  the 
jacket  water.  One  half  equals  257,000  B.  T.  U.  per  hour,  the  amount  of 
heat  to  be  absorbed  by  the  jacket  water,  and  to  be  surrendered  to  the 
water  in  the  cooler. 

If  250  B.  T.  U.  are  to  be  transferred  per  hr.  per  sq.  ft.  of  heating  sur- 
face per  1°  Fahr.  mean  temperature  difference  between  the  hot  and  cold 
water,  and  if  the  hot  water  is  circulated  around  the  tubes  at  a  velocity 
of  18  in.  per  second,  then  the  velocity  of  the  cooling  water  through  the 
tubes  must  be  about  19  in.  per  second.  For  a  heat  transfer  of  275  B.  T.  U. 
this  velocity  must  be  23  in.  per  second. 


RECOOLING    JACKET    WATER    BY    MEANS    OF    AIR 

The  Water  Cooler,  used  for  recooling  the  jacket  water  of  internal 
combustion  engines  by  means  of  air,  consists  of  a  bundle  of  straight  oval 
or  round  tubes.  The  ends  are  cast  into  the  tube  sheets.  The  jacket  water 
to  be  cooled  passes  through  the  tubes,  and  air  is  blown  across  the  tube 
surfaces  by  means  of  a  blower. 

The  small  weight  and  space  occupied  by  the  apparatus  make  it 
indispensable  for  this  purpose.  Oval  or  round  tubes  are  in  staggered 
formation.  Thus  the  air  is  split  into  numerous  fine  streams  and  comes 
into  thorough  contact  with  the  tube  surfaces.  The  frictional  resistance 
through  the  cooler  is  small.  The  use  of  oval  tubes  insures  high  heat 
transmission,  since  the  water  column  flowing  through  the  tube  is  of 
oval  cross  section  and  every  particle  of  water  is  close  enough  to  the  in- 
terior tube  surface  to  be  able  to  surrender  its1  heat  effectively  and  com- 
pletely. There  is  no  dead  central  core  of  water  as  in  round  tubes  of 
the  same  capacity. 

The  design  of  the  recooling  plant  must  be  based  on  the  maximum 
heat  that  is  to  be  absorbed  from  the  engine  by  the  jacket  water,  and 
surrendered  to  the  air  in  the  cooler.  Furthermore,  the  power  required 
by  the  'blower  should  remain  within  reasonable  limits, — at  the  utmost 


AUXILIARY  MACHINERY  AND  ACCESSORIES  193 

not  more  than  5  per  cent  of  the  engine  capacity, — the  air  should  be 
drawn  through  the  cooler  in  the  correct  manner. 

In  a  general  way,  it  may  be  stated  that  there  must  be  a  temperature 
difference  between  the  surrounding  air  and  the  water  leaving  the 
cooler  of  at  least  30°  Fahr.,  if  the  cooling  plant  is  not  to  be  abnormally 
large  and  expensive.  For  example,  if  a  recooling  plant  is  to  be  operated 
with  air  at  80°  Fahr.,  the  water  would  not  be  cooled  below  115°  Fahr. 
or  110°  Fahr.  at  the  lowest. 

Schutte  &  Koerting  Water  Coolers  are  built  in  sizes  adapted  for 
engine  capacities  of  5  H.  P.  up  to  large  units  of  200  H.  P.  For  still  larger 
units  several  coolers  are  used  in  combination. 


INTER   AND   AFTER-COOLERS    FOR   AIR   COMPRESSORS. 

The  air  cooler  is  extensively  used  in  connection  with  air  compressors 
for  cooling  the  compressed  air.  The  apparatus  is  made  to  withstand 
any  pressure  required,  and  is  designed  so  as  always  to  retain  the  ad- 
vantages of  a  very  compact  arrangement.  Round  tubes  are  employed 
and  the  tube  bundles  are  inserted  in  cast  iron  or  sheet  iron  casings. 

Both  oil  and  water  eliminaters  are  provided,  thus  practically  all 
of  the  entrained  moisture  and  oil  is  removed.  This  is  essential,  parti- 
cularly when  the  air  is  subsequently  used  in  air  agitators  around  machin- 
ery where  the  inter  and  after-cooling  methods  are  imperative.  Also  by 
insuring  the  removal  of  all  entrained  moisture,  the  possibility  of  free- 
zing in  winter  is  entirely  eliminated. 

The  air  is  carried  around  the  outside  of  the  tubes,  and  the  cooling 
water  through  the  tubes.  As  it  is  a  simple  matter  to  clean  the  insides 
of  the  tubes,  very  dirty  water  can  be  used.  Notwithstanding  the  small 
dimensions  of  the  apparatus,  the  resistance  to  flow  is  low,  and  large 
quantities  of  air  can  therefore  be  handled  with  small  frictional  losses. 

The  operation  of  a  two-cylinder  double-acting  two-stage  air  com- 
pressor with  an  inter-cooler  and  an  after-cooler  is  as  follows: 

Air  enters  the  cylinder  through  the  open  inlet  valve,  which,  at 
the  end  of  the  suction  stroke,  closes;  as  the  motion  of  the  piston  com- 
presses the  air  filling  the  cylinder,  the  discharge  valve  opens  automa- 
tically, and  allows  the  compressed  air  to  pass  the  inter-cooler,  where  it 
is  cooled,  and  thence  discharged  to  the  second  cylinder  or  to  the  subse- 
quent stage. 

During  its  passage  through  the  inter-cooler,  the  air  surrenders  to 
the  water  practically  all  the  heat  of  compression,  although  ,some  of  this 
heat  has  already  been  absorbed  by  the  water  in  the  compressor  water 
jacket. 

After  the  air  leaves  the  last  stage,  it  is  usually  conducted  to  an 
after-cooler,  where  the  heat  generated  in  the  final  stage  of  compression 
is  removed  in  exactly  the  same  manner  as  in  the  inter-cooler. 

The  cooled  high  pressure  air  then  passes  to  the  receiver,  where  it 
is  stored,  until  drawn  off  for  use  as  required. 


194 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


SPRAY   AIR   COOLER 


A  sectional  elevation  of  the  Schutte  &  Koerting  Spray  Air  Cooler 
is  shown  in  accompanying  illustration.  This  apparatus  is  of  highest 
value  in  successful  operation  of  Diesel  engines.  The  cooling  water  en- 
velopes and  circulates  around  the  tubes.  The  compressed  air  enters  the 
top  header,  flows  through  the  tubes  into  the  bottom  header,  thence 
passes  into  an  oil  and  water  eliminator.  This  is  a  circular  chamber  or 
tangential  groove  in  the  form  of  a  spiral. 


•Spiral  Cumber 


Oil  And  WV 
— Dra>n 


Sectional  Elevation  of  Spray  Air  Cooler  for  Diesel  Engines 


As  the  cooled  air  with  its  entrained  oil  and  moisture  is  passed 
through  the  spiral  chamber,  the  oil  and  water  are  -thrown  to  the  outside 
and  forced  through  suitable  openings  in  the  eliminator.  The  oil  and 
water  collect  in  the  bottom  of  the  cooler  whence  they  are  removed 
through  the  drain  shown. 

If  the  oil  and  water  are  not  removed  from  the  spray  air,  but  are 
carried  with  the  air  into  the  engine,  they  frequently  form  a  gritty  de- 
posit on  valves,  etc.,  which  in  many  instances  eventually  causes  a  serious 
explosion. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 
COMPRESSED    AIR    PREHEATER 


195 


When  heavy  oils  are  burned  in  Diesel  engines,  it  is  frequently  ne- 
cessary to  preheat  the  compressed  air  so  that  the  final  temperature  of 
compression  will  be  high  enough  to  vaporize  and  ignite  the  heavy  oil 
injected  into  the  cylinder. 


Sectional  Elevation  of  Air  Spray  Preheater. 


A  sectional  elevation  of  the  preheater  is  shown  in  the  accompany- 
ing illustration.  Primarily  the  apparatus  consists  of  a  cylindrical  tu- 
bular heater  in  which  the  exhaust  gases  from  the  engine  are  passed 
through  tubes  enveloped  by  the  compressed  air  to  be  heated.  The 
flow  of  heated  air  into  the  Diesel  engine  is  regulated  by  means  of  a 
suitable  valve. 

Preheating  the  air  decreases  its  density  and  therefore  the  work 
that  can  be  developed  by  a  given  volume.  This  is  of  particular  im- 
portance at  full  load.  Under  these  conditions  the  amount  of  preheating 
is  decreased  by  introducing  into  the  compressed  air  a  definite  amount 
of  cool  free  atmospheric  air.  The  quantity  admitted  is  closely  controlled 
by  means  of  a  suitable  valve. 


196 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


SCHUTTE   &    KOERTING'S    LATEST   IMPROVED   PUMP   FOR 
GATING  OIL,  THE  "NEIDIG  OIL  PUMP" 


LUBRf. 


The  importance  of  the  oil-pump  on  Diesel  engines  is  best  demonstrated 
when  following  the  principles  upon  which  this  prime  mover  depends.  The 
construction  of  the  pump  demands  careful  investigation  of  each  part,  cor- 
responding with  the  required  work  to  be  expected  of  this  highly  important 
apparatus.  Many  defects  in  operation  of  the  main  unit  are  directly  trace- 
able to  improper  design  and  lack  of  sufficient  knowledge  on  the  part  of 
builders  \vith  respect  to  the  oil  pump. 


The  "Niedig  Oil  Pump",  Specially  Adapted  on  Diesel  Machinery 


The  pump  used  for  the  purpose  of  supplying  an  average  stream  of 
liquid  in  power  plant  equipments  is  an  entirely  different  machine  from  the 
type  used  for  high  pressure  oil-supply  purpose  of  a  high-compression 
Diesel  engine,  or  for  such  purposes  where  lubricants  are  supplied. 


Neidig  Oil  Pump — Interior  Arrangement 


AUXILIARY  MACHINERY  AND  ACCESSORIES  197 

In  figure  (a)  a  Schutte-Koerting  "Neidig  Oil  Pump"  illustration  is 
given.  As  will  be  noticed  from  the  illustrations,  the  pump  follows  along 
the  lines  of  the  well  known  gear-pump,  often  found  in  plants  where 
heavy  viscous  liquids  require  a  pump  of  highest  grade. 

A  special  feature  of  this  pump  is  the  provision  of  stationary  guide 
ring,  or  distance  ring,  this  is  fixed  concentric  with  the  revolving  gears, 
and,  owing  to  the  design,  enables  the  conversion  ofi  velocity  into  pressure 
head  to  be  very  effectively  accomplished,  thus  increasing  not  only  the 
possible  height  of  lift,  but  also  the  working  efficiency  of  the  pump  from 
the  standpoint  of  the  desired  pressure. 


Neidig  Oil  Pump — Gear  Arrangement 

This  pump  possesses  many  advantages.  Conspicuous  amongst  these 
being  the  small  number  of  working  parts,  compactness,  low  first  cost,  and 
minimum  wear  and  tear. 

In  calculations  relating  to  these  pumps  the  following  formula  will  be 
helpful: 

Let  .S  —  speed  of  periphery  of  wheel  in  feet  per  second. 

Let  H  =  height  in  feet  to  which  liquid  is  to  be  delivered. 

Let  D  =  diameter  of  wheel  in  feet. 

Let  G  ==  gallons  of  liquid  delivered  per  minute. 

Let  R  =  revolutions  per  minute. 

The  horsepower  of  driving  medium  required  will  be  found  by  multi- 
plying the  height  in  feet  by  the  quantity  of  liquid  in  pounds  pe*r  minute, 
and  by  the  efficiency  of  the  pump  and  main  unit,  and  dividing  by  33,000. 
The  efficiency  of  the  pump  may  be  anything  from  0.55  to  0.65,  and  the* 
efficiency  of  the  driving  power,  say,  0.85,  the  combined  efficiencies  being 
thus  equal  to  from  70  to  75  per  cent. 

Its  action  depends  upon  centrifugal  principle.  Until  quite  recently 
a  great  deal  of  objection  was  found  to  be  prevalent  to  the  use  of  centri- 
fugal types  of  pumps  on  Diesel  machinery.  The  principal  reason  of  ob- 
jection was  a  low  efficiency  in  comparison  to  plunger  types.  These  ob- 


198 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


jections  were  never  based  upon  sound  reason,  inasmuch  as  pumps  driven 
by  centrifugal  force  have  many  advantages,  such  as  lessening  of  parts, 
easy  maintenance,  lack  of  complicated  mechanism,  etc. 

In  order  to  emphasize  the  necessity  to  provide  for  strainers  on  appar- 
atus where  the  purpose  is  to  supply  oil  for  the  engine,  the  sectional  view 
of  Schutte-Koerting's  Duplex  Oil  Strainer  is  shown.  The  Duplex  Oil 
Strainer  removes  dirt,  sediment,  and  any  foreign  material  that  has  acci- 
dentally gotten  into  the  oil. 


Sfrainer- 


b±a 

Sectional  View  of  Duplex  Oil  Sir, .in,  r 


It  is  of  sufficient  capacity  so  that  one  side  may  be  cut  out  for  clean- 
ing purposes  without  interrupting  the  flow  of  oil  through  the  other  side, 
that  is,  one  side  of  the  strainer  can  be  cleansed  while  the  apparatus  is 
running  under  full  power. 

It  is  operated  with  a  single  lever.  It  has  a  free  area  through  tht> 
straining  screens  that  permits  of  long  usage  without  causing  system  to 
become  choked  and  clogged. 

Sometimes  the  strainer  is  by-passed,  the  by-pass  being  provided  with 
a  relief  valve  so  adjusted  that  it  opens  when  a  fixed  differential  pressure 
occurs  across  the  strainer.  In  this  way  the  oil  flow  is  not  interrupted; 
but  an  alarm  must  be  provided  to  indicate  when  the  valve  opens,  other- 
wise the  clogged  strainer  will  go  unnoticed. 


AUXILIARY  MACHINERY  AND  ACCESSORIES  199 

FORCE   FEED  OILERS 

The  successful  operation  of  any  internal  combustion  engine  depends 
largely  upon  its  lubrication  and  no  matter  how  perfect  the  design,  the  en- 
gine will  not,  and  cannot,  run  satisfactorily  without  particular  attention 
to  this  feature.  (Satisfactory  lubrication  is  more  than  the  matter  of  oil. 
It  is  the  question  of  the  oil  reaching  the  right  place  at  the  right  time  and 
the  right  quantity.  An  excessive  amount  of  oil  will  cause  the  engine 
cylinders  and  valves  to  carbonize,  resulting;  in  leaky  valves  and  loss  of 
power.  It  will  decrease  the  efficiency  of  the  engine.  The  results  of  in- 
sufficient oil,  such  as  burned-out  bearings,  scored  cylinders,  etc.,  are 


''Direct  Acting"  Manzel  Force-Feed  Oiler — Fig.    (1) 

too  well  known  to  require  discussion  here.  While  in  larger  types  of 
Diesels,  special  oil  force-feed  systems  have  been  provided  for,  neverthe- 
less the  type  made  by  the  Manzel  Co.  are  exceedingly  satisfactory  on 
smaller  capacities  of  Diesel  engines. 

The  arrangement  of  this  type  is  exceedingly  simple.  By  the  use 
of  the  so-called  "sight-feed"  oilers,  trouble  will  be  overcome  by  watch- 
ing the  sight  at  the  top  of  the  lubricator.  Before  starting  the  engine,  give 
the  handle  a  dozen  turns  so  as  to  get  the  oil  to  the  bearing  before  the 
engine  has  started.  If  the  engine  has  been  left  to  stand,  the  bear- 
ing surfaces  are  subject  to  become  heated,  provided  lubricant  has  not 
been  furnished.  This  type  of  oiling  system  enables  the  operator  to 
know — not  guess — how  much  oil  is  being  supplied  to  the  cylinder  bear- 
ing. The  oil  is  always  supplied  in  accordance  to  the  speed  of  the  engine, 
whether  the  engine  stops,  islows  down,  starts,  the  oiler  corresponds  to 
the  engine's  actions.  It  always  supplies  the  exact  amount  of  oil  for 
every  part  of  the  engine,  depending  upon  the  requirements. 

To  regulate  the  Force-Feed  Oiler  move  the  stroke  lever  at  the  left 
in  or  out  to  shorten  the  stroke  or  lengthen  it  as  the  requirements  may 
call  for.  To  regulate  the  feed  of  the  oil  to  the  bearing  surfaces  of  the 
cylinder,  take  a  screw-driver  and  turn  the  feed  regulator  to  the  right  or 
left  for  increase  or  decrease  of  oil  to  be  shown  at  the  sight.  In  case 
the  oil  pipes  from  the  lubricator  to  the  bearing  surface  should  become 
clogged  in  any  way,  disconnect  the  pipe  line  at  both  ends,  and  if  air  is 
available,  insert  the  pipe  line  at  the  end  of  the  hose  and  turn  on  the  air. 


200  AUXILIARY  MACHINERY  AND  ACCESSORIES 

Be  sure  that  the  pipe  is  clean  before  attempting  to  assemble.  Never 
let  the  lubricator  become  dry,  but  keep  an  even  supply  of  oil  in  the  res- 
ervoir. 

Oiling  by  means  of  gravity  oil  cups  or  pressure  lubricators  is  more 
or  less  a  matter  of  guess  work.  This  method  is  wasteful,  because  the 
feed  cannot  be  adjusted  accurately,  and  the  oil  supply  is  seldom  pro- 
portional to  the  speed  of  the  engine.  Changes  in  temperatures  affect  the 


OIL  INLET 

Sectional  View  of  Manzel  Force-Feed  Lubricator — Fig. 


flow  of  the  oil,  with  the  result  that  the  engine  gets  too  much  or  too 
little,  and  to  keep  it  adjusted  correctly  requires  constant  attention.  Even 
then  it  is  not  always  dependable. 


MECHANICAL    OIL    PUMPS 

Where  mechanical  oil  pumps  are  employed,  the  timing  requires 
accurate  attention.  In  this  case  it  will  cause  the  oil  to  be  injected  through 
a  nozzle,  as  the  piston  is  below  the  central  point  of  its  travel.  The 
spraying  of  the  oil  takes,  place  at  this  period,  covering  a  considerable 
area,  even  though  the  clearance  between  the  piston  and  cylinder  walls 
is  small.  The  piston,  as  it  moves  upward,  swabs  this  oil  over  the  cyl- 
inder walls, 


AUXILIARY  MACHINERY  AND  ACCESSORIES  201 

RECORDING    INSTRUMENTS 

To  establish  an  accuracy  of  operation  in  Diesel  engineering,  it  is 
imperative  that  a  plant  should  be  equipped  with  instruments  by  which 
posisiible  defects  are  shown.  With  this  object  in  view,  up-to-date  plants 
depending  upon  the  reliability  of  machinery  and  the  engineer  in  charge, 
are  placed  in  position  to  establish  efficiency. 

It  is  through  the  use  of  instruments  that  operators  are  enabled  to 
ascertain  the  highest  temperature  in  the  cycle,  either  by  cause  of  com- 
bustion or  compression  of  air. 

The  overheating  of  bearings  may  be  avoided  by  having  instruments 
installed  in  proper  places,  warning  the  operator  of  approaching  danger. 

The  storage  of  fuel-oils  demands  cautious  observation,  eliminating 
possible  explosion.  Instruments,  showing  the  existing  temperature 
should  be  installed. 

While  it  is  true,  that  engine-rooms  of  Diesel  plants  are  seldom 
above  normal  heat  temperature,  nevertheless  recording  instruments 
should  be  considered  a  necessary  equipment,  in  particular  where  Re- 
frigeration machinery  is  in  conjunction  with  the  plant. 

The  temperature  of  sea  water  should  be  taken  on  marine  work, 
especially  on  ships  going  on  oversea  voyages.  This  is  absolutely  neces- 
sary and  should  be  recorded  every  24  hours  in  the  engine  room  log. 

Instruments  to  establish  the  specific  gravity  of  fuel  oils  should  be 
on  hand.  It  leaves  no  argument  in  regard  to  receiving  the  proper 
quality  of  fuel  for  the  engine.  There  is  very  little  value  in  water,  and 
oils  containing  low  specific  gravity  should  be  avoided. 

Receivers  of  Compressors  should  be  equipped  with  accurately  tested 
gauges,  Safety  valves,  Relief  valves  and  Bottom-  blows.  The  latter 
valve  is  a  vital  equipment  on  compresised  air-receivers.  They  should 
be  placed  as  low  as  possible,  to  make  it  possible,  to  drain  all  existing 
water  which  accumulates  on  the  bottom  of  the  tank.  Water  in  air  is 
injurious  to  valves  and  piping.  The  acid  in  the  water  will  eventually 
act  as  a  detrimental  factor  on  metal. 

Pressure  gauges  should  be  tested  occasionally  to  establish  their  cor- 
rectness. To  place  reliability  on  mechanical  contrivances,  such  as  safety 
valves,  relief  valves,  etc.,  should  be  discouraged,  as  it  may  lead  to  acci- 
dents of  serious  consequences. 

The  Ashton  Improved  Dead-Weight  Pressure  Gage  Tester,  as  shown 
in  the  illustration,  offers  in  convenient  form  an  improved  method  for 
accurately  testing  pressure  gauges  by  means  of  weights,  and  is  a  recog- 
nized standard  extensively  adopted  for  this  important  service.  It  is 
equal  in  accuracy  to  that  of  a  mercury  column,  and  has  the  advantage  of 
being  more  compact,  portable  and  much  lower  in  cost.  These  testers  are 
also  much  more  preferred  over  the  ordinary  styles  of  similar  designs 
because  of  their  special  distinctive  construction  with  double  area  piston. 
This  exclusive  feature  makes  it  possible  to  make  tests  within  their 
designated  range  of  pressure  with  only  one-fourth  the  usual  number  of 


202  AUXILIARY  MACHINERY  AND  ACCESSORIES 

weights,  which  is  a  matter  of  considerable  convenience,  as  well  as 
economy  of  time.  In  following  instructions  it  will  be  observed  that 
accuracy  can  be  obtained  when  properly  applied. 

For  low  range  pressure  testing  the  tester  should  be  adjusted  so  as  to 
make  use  of  the  combined  large  and  small  area  of  the  piston,  which 
is  done  by  closing  the  left-hand  cock  on  the  vertical  pressure  cylinder 
and  opening  the  right-hand  one.  When  the  maximum  pressure  with  this 
adjustment  is  obtained,  and  it  is  desired  to  test  at  higher  pressures, 


Ashton  Improved  Dead-Weight  Pressure  Gauge  Tester 


the  reverse  adjustment  of  the  cylinder  cocks  is  made  with  the  left 
opened  and  the  right  one  closed.  This  makes  the  machine  operate  on 
the  small  area  of  the  piston  only,  and  the  pressure  then  exerted  will  be 
four  times  greater  than  before,  which  applies  to  the  weight  holder  as  well 
as  to  each  of  the  weights.  These  changes  of  regulation  can  be  made 
while  the  machine  is  in  use  and  without  taking  it  apart.  It  is  necessary, 
however,  to  remove  all  pressure  in  the  tester  by  unscrewing  the  hand- 
wheel  before  making  such  re-adjustments. 

The  tester  should  always  be  placed  in  a  level  position  so  that  the 
weight  piston  will  stand  exactly  vertical.  To  insure  accuracy  of  read- 
ings, the  piston  should  be  revolved  slowly  to  reduce  any  friction  there 
might  be  in  the  cylinder. 

As  the  weights  force  the  piston  to  the  bottom  of  the  cylinder,  the 
hand-wheel  should  be  screwed  in  more,  thus  raising  the  piston  and  pre- 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


203 


venting  it  from  striking  the  bottom.  All  interior  parts  should  be  kept 
clean,  and  best  results  are  obtained  by  using  sperm  oil  or  similar  light 
grade. 

In  preparing  the  tester  for  use,  the  three-way  cock  on  the  gage 
connection  arm  should  be  closed  by  turning  the  lever  handle  to  a  vertical 
position.  The  hand-wheel  screw  should  be  screwed  into  the  oil  reservoir 
as  far  as  it  will  go.  Then  remove  cap  on  top  of  vertical  cylinder  and 
slowly  fill  cylinder  with  oil,  during  which  operation  the  hand-wheel  should 
be  gradually  unscrewed  until  the  instrument  is  completely  filled.  The 
gage  to  be  tested  should  next  be  applied,  and  the  three-way  co'ck  opened 
by  turning  lever  handle  horizontally  to  the  right.  The  weight  pistons 
with  tray  may  then  be  inserted  in  the  cylinder,  making  the  tester  com- 
plete and  ready  for  use  with  the  application  of  the  weights. 


Ashton  Inspector's  Testing  and  Proving  Outfit 


The  piston  with  weight  holder,  as  well  as  each  of  the  weights,  is 
plainly  marked  with  the  pounds  pressure  they  will  exert  on  the  gage, 
with  double  area  adjustment.  When  the  single  area  adjustment  is  being 
used  the  pressure  as  above  stated  is  four  times  greater. 

In  accompanying  illustration  the  Ashton  Inspector's  Testing  and  Prov- 
ing Outfit  is  shown.  This  outfit  is1  particularly  adapted  to  the  require- 
ments of  operators  on  ships  going  on  long  voyages  and  around  plants 
where  large  Diesels  are  in  operation. 

In  the  illustration  of  the  Ashton  Improved  Pressure  Recording  Gage 
it  will  be  seen  that  the  chart  is  graduated  with  pressure  lines  and  in 
fractions  of  an  hour,  and  is  rotated  by  an  eight-day  clock  movement. 
The  chart  is  ordinarily  made  to  rotate  once  in  24  hours. 


204 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


With  the  use  of  this  gage  in  the  engine  room,  there  is  always  a 
tendency  to  carefully  watch  the  entire  operation  of  the  engine.  The 
record  of  the  chart  shows  the  actual  existing  pressure  on  the  air  line 
and  with  the  equipment  of  a  gauge  of  this  kind  any  irregularity  which 
may  cause  serious  breakdowns  is  immediately  recorded. 


Ashton  Improved  Pressure  Recording  Gage 


Tycos  Recording  and  Index  Thermometer 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


205 


In  the  following  illustration  we  have  a  Recording  Instrument,  which 
automatically  writes  in  ink  on  a  revolving  paper  chart  a  continuous 
record  of  the  temperature  to  which  its  bulb  is  subjected.  The  self-con- 
tained recorder  has  the  bulb,  or  sensitive  member,  inside  the  case, 
whereas  with  the  cavillary-form  instrument  the  bulb  may  be  located  at 
a  distance. 


Ash  ton  Pressure  Gauge — Double   Spring  Arrangement 

An  Index  Thermometer  is  an  indicating  instrument  having  a  bulb 
or  sensitive  member  which  may  be  located  at  a  distance  from  the  case, 
so  that  the  latter  can  be  located  at  a  point  easily  accessible  for  reading 
the  temperature. 

It  may  generally  be  stated  that  the  mercury  type  is  best  adapted  to 
applications  which  require  accurate  readings  over  a  wide  temperature 
scale,  and  where  the  length  of  flexible  connecting  tubing  does  not  exceed 
20  or  25  feet. 


Ashton  Pressure  Gauge — Single  Spring  Arrangement 


206 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


Fig.l 


Pneumercator  Gauge 


AUXILIARY  MACHINERY  AND  ACCESSORIES  207 

Instruments  of  this  kind  are  made  in  temperature  ranges  within  the 
limits  of  40°  below  and  1000°  above  zero,  Fahrenheit.  The  vapor  ten- 
sion type  is  particularly  recommended  in  Diesel  operation,  where  the 
temperatures  are  within  the  limits  of  100°  and  600°  Fahrenheit,  and 
particularly  where  long  lengths  of  flexible  connecting  tubing  are  neces- 
sary, leading  to  fuel  bunkers  or  parts  of  the  ship  or  plant  where  a  pre- 
determined temperature  is  imperative. 

In  Figure  1,  a  Pneumercator  Ship's  Draft  and  Tank  Gauge  is  shown. 
The  application  and  advantages  of  Pneumercator  Tank  Gauges  as  ap- 
plied to  oil  cargo,  fuel  oil  settling,  Ballast/  or  water  tanks,  or  bilges,  is 
recognized  in  marine  service.  They  indicate  the  depth,  volume  or  weight 
of  the  tank  contents. 

They  provide  an  accurate  and  simple  means  of  checking  invoices, 
fillings  and  withdrawals,  and  will  record  the  amount  of  fuel  consumed 
per  hour  or  per  day.  They  furnish  a  perpetual  inventory  of  tank  con- 
tents. By  their  use  there  is  no  danger  of  overfilling  or  flooding  decks. 

It  will  be  observed  in  Figure  1  that  the  installation  is  exceedingly 
simple.  It  indicates  for  and  aft  drafts  of  the  vessel,  registers  mean 
draft  and  corresponding  tons  dead  weight  displacement.  It  weighs  bulk 
cargoes  loaded  or  discharged,  with  close  accuracy,  and  is  of  invaluable 
assistance  in  trimming  the  vessel. 

The  operation  of  the  Pneumercator  Gauge  is  dependent  solely  upon 
the  maintenance  of  the  true  static  balance  between  the  head  of  liquid 
to  be  measured  and, the  column  of  mercury  or  other  indicating  medium 
in  the  gauge.  The  pressure  of  the  liquid  is  transmitted  to  the  gauge  by 
air  confined  in  a  small  connecting  tube  between  the  liquid  (at  the  datum 
line  above  which  the  head  is  measured)  and  the  gauge. 

To  establish  the  datum  line  a  hemispheric  vessel,  or  balance  cham- 
ber, is  located  at  a  predetermined  level  below  the  surface  of  the  liquid. 
An  orifice  in  the  lower  portion  of  this  balance  chamber  admits  the  liquid 
to  the  interior.  In  taking  a  reading,  air  is  forced  into  this  balance 
chamber,  thus  expelling  the  liquid  from  the  balance  chamber  and  es- 
tablishing the  datum  level.  Excess  air  merely  passes  out  as  bubbles, 
hence  the  pressure  on  the  confined  air  remains  constant  and  equal  to  the 
head  of  liquid  standing  above  the  datum  line. 

When,  by  manipulating  a  control  valve,  this  air  is  admitted  to  the 
gauge,  the  mercury  column  rises  to  balance  the  pressure  of  the  liquid 
head  and  establishes  a  precise  reading  on  the  gauge  scale. 

The  elements  required  are  therefore:  (1)  A  balance  chamber;  (2) 
A  mercury  or  other  gauge;  (3,)  A  hand-pump  or  source  of  compressed 
air,  and  (5)  A  control  valve  attached  to  the  gauge  and  connected  by 
small  piping  to  the  balance  chamber  and  to  the  source  of  compressed 
air.  (See  Fig..  1). 

The  instrument  may  be  installed  at  any  desired  point,  regardless 
of  the  location  of  the  balance  chamber.  Indirect  leads  and  any  number 
oi  bends  in  the  air  line  in  no  wise  affect  the  working  system.  As  the 
air  is  merely  trapped  in  the  balance  chamber  and  piping,  the  pressure 


208  AUXILIARY  MACHINERY  AND  ACCESSORIES 

which  it  transmits  is  unaffected  by  varying  temperatures  through  which 
the  latter  may  pass,  and  the  instrument  is  of  unvarying  accuracy.  This 
instrument  will  operate  with  equal  accuracy  on  tanks  open  to  atmosphere, 
or  under  pressure.  Their  precision  is  not  affected  by  temperature 
changes. 


THE  IMPORTANCE  OF  PROPER  VALVES 

In  selecting  valves  for  Air-line  connections  or  around  the  main  or 
auxiliary  engines,  is  a  matter  which  should  be  given  careful  study.  Un- 
like the  steam  engine,  where  a  leakage  of  steam  does  not  impair  the 
operation  of  the  plant  to  a  great  extent,  the  opposite  may  occur  in  Diesel 
operation. 

In  packing  glands  around  valves,  the  same  should  be  done  exceed- 
ingly skillfully.  Steam  packing  will  not  do  around  Diesel  machinery, 
neither  will  steam  valves  be  satisfactory  in  a  plant  operated  by  Internal 
Combustion  engines. 


INLET 


Ideal  Valve  for  Use  Around  Internal  Combustion  Machinery 


It  is  but  natural  that  leakages  should  be  avoided.  It  will  be  seen 
in  the  illustration  showing  the  Lunkenheimer  Balanced  Valve,  that 
the  manufacturers  have  made  a  special  type  answering  the  purpose  of 
proper  valve  equipment. 


AUXILIARY  MACHINERY  AND  ACCESSORIES  209 

All  Lunkenheimer  Balanced  Valves  should  be  connected  so  that  the 
inlet  pressure  will  be  above  the  disc.  The  method  of  operation^  assum- 
ing that  the  valve  is  closed  and  under  pressure,  is  as  follows: 

Air  will  pass  through  the  drain  in  the  disc  cylinder,  just  above  the 
main  disc  and  thence  through  the  ports  E  into  the  balancing  cylinder  F. 
The  full  inlet  pressure  will  then  be  on  top  of  the  disc  and  materially 
assist  in  maintaining  a  tight  valve. 

When  it  is  desired  to  open  the  valve,  the  hand-wheel  L  is  turned 
about  one-quarter  of  a  revolution.  The  stem  will  then  be  in  a  position 
shown  in  the  illustration  with  the  opening  to  the  by-pass  disc  I  un- 
covered. Air  will  immediately  pass  through  the  by-pass  disc  and  out 
ports  in  the  main  disc  guide  stem  N,  equalizing  the  pressure  in  the  bal- 
ancing cylinder  and  below  the  main  disc. 

Further  turning  of  the  hand-wheel  will  open  the  main  valve,  and 
because  of  its  balanced  condition,  this  operation  may  be  accomplished 
with  negligible  effort. 


Ashton's  Spring  Lever  Pop  Valve — Exposed 

It  will  be  observed  that  the  by-pass  construction  of  this  valve  not 
only  permits  the  ready  establishment  of  equalized  pressure,  but  affords 
an  unusually  safe  and  accurate  restriction  of  the  volume  of  air  tranj- 
mitted  to  the  main  unit  during  the  "warming  up"  process. 

The  small  drain  hole  in  the  side  of  the  disc  cylinder  also  serves 
to  relieve  accumulation  of  water,  which  would  otherwise  leak  in  the 


210 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


valve-arrangement  on  the  engine  when  the  valve  is  connected  in  a  ver- 
tical position. 

The  disc  cylinder  piston  ring  is  of  sufficiently  loose  fit  to  provide 
adequate  drainage  when  the  valve  is  placed  horizontally. 

The  removal  of  moisture,  always  present  in  air,  is  essential  to 
safety  and  continuity  of  service.  The  varied  requirements  of  piping  in- 
stallations make  it  impracticable  to  provide  an  arbitrarily  located  "drip" 
connection  on  the  Balanced  Valve,  but  each  layout  must  provide  ade- 
quate drainage  of  all  points  at  which  such  accumulation  would  other- 
wise occur. 

In  accompanying  illustration  of  the  Outside  Spring  Safety  Pop 
Valve,  an  excellent  view  is  allowed,  giving  vital  parts  of  this  necessary 
equipment  on  Air-Tanks. 

The  purpose  of  the  safety  valve  is  to  prevent  the  pressure  of  air- 
storage  tanks  from  rising  above  a  certain  definite  point,  dependent  on 
the  construction  of  the  tank  and  the  condition  under  which  it  is  to 
operate.  The  function  must  be  performed  automatically  and  under  op- 
erating conditions  that  may  arise. 

There  are  obviously  two  essential  requirements  that  must  be  com- 
plied  with   in   any   safety   valve   in   order   to   guarantee    its   satisfactory 
performance:     1st,  Mechanical  Reliability,  and   2nd, 
Adequate  Relieving  Capacity. 

Safety  valves  should  be  connected  directly  to  the 
storage  tank,  and  in  case  it  is  found  necessary  that 
it  should  be  connected  to  any  outlet  connection,  un- 
der no  circumstances  should  the  area  of  such  con- 
nection be  less  than  that  of  the  valve  inlet.  A  close 
nipple  should  be  used  in  case  a  threaded  connection 
is  necessary. 

In  no  case  should  a  stop  valve  or  other  fitting 
Ibe  placed  between  a  Pop- Valve  and  the  air-outlet  nor 
pn  the  discharge  outlet  between  safety  valve  and  the 
'atmosphere. 

If  the  laws  governing  the  installation  permit 
adjustment  of  pressure-settings,  the  following  direc- 
tions should  be  observed  in  effecting  adjustment  of 
Lunkenheimer  Pop  Safety  Valve: 

A  change  in  the  relieving  pressure  may  readily 
be  made  by  removing  the  cap  at  the  top  of  the  valve 
and  adjusting  screw — turning  the  latter  down  for 
higher  pressure  and  up  for  a  lower  pressure. 

Ashton's  Relief  Valve 

The  amount  of  pressure  should  carefully  be  determined  and  the 
setting  of  pre-determined  pressure  necessary  to  assure  the  safe  carrying 
capacity  of  storage  tanks  or  reservoirs  should  at  all  times  correspond 
with  the  pressure-gauge. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 
SILENCERS 


211 


In  the  following  illustration  a  Silencer  is  shown.  These  Silencers 
reduce  the  noise  of  the  exhaust  of  an  engine.  In  many  cases  these 
Silencers  are  installed  both  upon  the  inlet  and  exhaust,  as  it  has  fre- 


Illustration  of  "Maxim"   Silencer. 


quently  been  found  that  the  suction  or  inlet  of  oil  engines  and  the 
section  of  air-compressors  is  the  cause  of  nearly  as  much  noise>  as  the 
exhaust.  They  offer  such  a  low  back  pressure  that  the  most  sensitive 
engines  can  be  equipped  to  operate  properly  and  quietly. 


212 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


THE  SPERRY  MAGNETIC  CLUTCH  COUPLING 

The  Sperry  type  of  Magnetic  Coupling  or  Clutch  has  been  used 
successfully  on  submersible  crafts  for  a  number  of  years.  It  may  well 
be  considered  a  clutch  arrangement  of  exceptional  reliability,  in  par- 
ticular on  marine  machinery  where  power-transmission  has  to  be  depended 
upon  assuring  immediate  control  of  the  engine. 

This  type  of  clutch  was  developed  as  a  by-product  of  several  years' 
experimentation  and  development  of  an  Electric  Transmission.  It  has 
'been  built  in  large  range  of  sizes  and  powers  and  has  been  found  par- 
ticularly adapted  to  certain  conditions  where  an  extreme  flexibility  com- 
bined with  self-aligning  characteristics  is  desired,  together  with  speed 
and  quick  response  in  management  of  the  power  unit. 


Floating  Steel 
Teefh 


Dn  vinq  Rotor  -  ^ 
Teeth 


F/LJ  wheel 
/'Driving  Element 


Driven  Element 


Non-Magnetic 

of  Magnetic  Conductor 


Approx.  Relation  of 
Teeth  at  Max  Torque 


Fig.  /.     Section  Through  Electromagnetic  Clutch 


In  this  form  of  Clutch  Coupling  torsional  resistance  is  developed,  due 
to  the  bending  or  distortion  of  the  magnetic  flux  stream  passing  from 
the  teeth  of  one  polar  projection  through  floating  steel  teeth  embedded 
in  non-magnetic  material  and  into  the  teeth  on  the  opposite  polar  pro- 
jection. (See  figure  1.)  The  component  parts  of  the  Coupling  are  so 
arranged  as  to  enable  the  distortion  of  the  flux  stream  to  be  made  in 
the  plane  of  revolution  and  a  perfect  torsional  cushion  is  thus  provided. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


213 


Simple  and  Rugged  Construction:  The  component  parts  of  the 
coupling  are  of  an  extremely  simple  form  as  may  be  noted  from  figure  3, 
all  parts  being  substantial  and  rugged  form.  As  there  is  no  mechanical 
contact  in  the  plane  of  revolution,  the  component  parts  are  not  subjected 
to  shock  of  any  kind  and  there  is  no  liability  of  parts  becoming  loosened, 
worn,  or  broken,  due  to  the  severest  condition. 

The  half  coupling  carrying  the  floating  teeth  is  normally  centered  by 
a  sleeve  or  ball  bearing  projecting  from  the  opposite  half  of  the  coupling. 
This  centering  projection  maintains  a  normal  condition  of  the  air  gap  and 
prevents  exterior  forces  due  to  shaft  misalignment  or  other  conditions 
disturbing  the  proper  relation  of  the  coupling  parts.  The  air  gaps  main- 
tained in  the  coupling  are  relatively  large  and  the  floating  magnetic  teeth 
are  cast  solidly  in  a  non-magnetic  ring  which  is  made  by  a  process  in- 
suring permanent  retention  of  the  teeth  and  safety  against  all  of  the  work- 
ing and  handling  conditions  which  may  be  encountered  in  assembling 
and  other  unforeseen  occasions  aboard  ship. 


Fig.  2.     General  Arrangement  of  Sperry  Gyroscope  Co.'s  Electromagnetic 

Clutch. 


The  energizing  coil  of  these  couplings  consists  of  a  single  circular 
coil  of  relatively  large  size  wire  which  is  wound  in  a  form  and  impreg- 
nated with  Bakelite.  It  is  insulated  to  withstand  the  worst  conditions 
of  temperature,  dampness  and  operation.  The  amount  of  current  required 
for  energizing  is  extremely  small  for  the  power  transmitted,  as  but  a  few 
watts  are  necessary  and  only  a  fraction  of  a  kilowatt  is  required  for  a 
coupling  of  large  capacity.  The  exiting  current  is  led  into  the  coil  through 
a  simple  form  of  brush  holder  bearing  on  collector  rings  which  are 
mounted  on  and  form  part  of  one  of  the  coupling  elements.  The  standard 
couplings  are  designed  to  be  operated  at  a  potential  of  110  volts  D.  C., 
although  exiting  coils  may  be  wound  for  any  voltage  up  to  500.  These 


214 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


couplings  are  adapted  only  for  operation  on  direct  current  circuits  ana 
will  not  operate  on  alternating  current  systems  of  any  voltage. 


4000 


1600 


800] 


Pull-Out 


=p 


Ra+ect  Torque 


Z      4-      6       6      10     IZ      14     16     16     ZO    ZZ    Z4     Z6    Z6    30 

Relative  Speed  Difference  in  Revolutions  per  Second 


Fig.  3.     Speed-Torque  Curve  of  Electromagnetic  Clutch. 


TABiLE  OF  COMMERCIAL  RATINGS  OF  SPERRY  ELECTRO 
MAGNETIC  CLUTCH 

Normal  rat- 

Clutch 

Max.  pull- 

ing  constant 

Max. 

Max.  start- 

Coupling 

out-torque 

torque 

H.  P.  per 

speed 

ing  torque 

Number 

Ib.  ft. 

Ib.  ft. 

100  rev. 

R.P.M. 

Ib.  ft. 

* 

t 

$ 

5 

300 

175 

3.25 

3000 

75 

9 

900 

500 

9.0 

2500 

225 

14 

2500 

1200 

24 

2000 

625 

18 

4500 

2200 

42 

1600 

1250 

24 

10000 

4500 

85 

1200 

2500 

32 

20000 

9000 

170 

900 

5000 

40 

40000 

16000 

305 

750 

10000 

*Larger  sizes  may  be  designed  for  special  requirements. 

JValues  given  are  for  a  speed  difference  of  1000  ft.  per  minute  between 

halves    of   coupling.      Lower    speed    differences    give    somewhat    less 

starting  torque. 

fConstant  torque  ratings  are  based  on  such  prime  movers  carrying  smooth 
loads.  For  pulsating  loads  a  factor  should  be  introduced  varying 
from  iy2  to  3,  depending  on  specific  characteristics  of  the  drive. 


AUXILIARY  MACHINERY  AND  ACCESSORIES  215 

The  clutch  is  energized  by  the  simple  pressing  of  a  button  and  the 
driven  part  is  gradually  speeded  up  and  brought  into  synchronism  with 
driving  part.  After  clutch  is  synchronized  no  slipping  takes  place  unless 
a  load  is  thrown  on  clutch  greatly  exceeding  its  rated  capacity.  This 
characteristic  may  be  utilized  in  many  applications  as  a  guard  against 
overloading  some  particular  part  of  the  system.  No  detrimental  effect 
is  caused  by  starting  continuously  even  under  load. 

As  will  be  seen  in  the  illustration  (figure  3),  by  carefully  studying 
this  card,  that  the  strain  in  consequence  of  use  of  this  type  of  magnetic 
clutch  is  far  less  than  that  of  the  different  mechanical  equipments  ge^ 
erally  in  use  on  engines  depending  upon  reverse-gear.  No  doubt  this  type 
of  clutch  has  many  advantages,  in  particular  when  installed  on  crafts 
where  quick  maneuvering  must  be  accomplished. 


REVERSE    GEARS    FOR    MARINE    ENGINES 

Of  vital  importance  is  the  reverse  gear  on  marine  engines  depending 
upon  this  equipment.  A  gear  must  conform  with  the  requirements  ex- 
pected of  it.  The  maneuvering  of  the  ship,  and,  in  fact,  the  safety  itself, 
depends  on  the  reliability  displayed  in  the  reverse-gear.  It  must  be  built 
strong  and  rigid,  withstanding  all  rough  usages  it  is  confronted  with. 

The  Paragon  Reverse  Gear,  which  is  shown  in  accompanying  illustra- 
tion, was  designed  for  engines  where  the  bed  is  extended  to  accomodate 
it,  in  conjunction  with  the  unit  power  plant.  It  is  also  used  in  connection 
with  any  motor  where  a  firm  foundation  or  angle  iron  support  is  pro- 
vided. 

On  account  of  its  unusual  compactness,  it  takes  up  a  very  small 
amount  of  room.  The  forward  end  of  the  gear  is  bored  out  to  directly 
accommodate  the  crank  shaft  of  the  motor.  The  propeller  shaft  can  be 
fitted  directly  into  the  rear  end  of  the  gear,  which  is  bored  out  to  the 
propeller  shaft  size.  Ingenious  stop  links  lock  the  gears  securely  in  either 
position.  This  type  permits  the  operating  lever  to  be  placed  on  either 
port  or  starboard  side. 

In  following  detailed  explanation  pertaining  to  the  adjusting  of  the 
gear,  by  carefully  using  the  illustration  shown  here  it  will  be  found  in- 
structive. 

How  To  Adjust  the  Gear:  It  is  necessary  that  the  gear  should 
be  properly  adjusted  before  it  is  permitted  to  operate.  The  forward  drive 
of  the  Paragon  gear  is  obtained  by  means  of  the  disc  clutch  which  locks 
to  the  case.  Thus  the  whole  gear  revolves  as  a  solid  coupling.  The  lock- 
ing, or  clamping,  of  these  discs  is  brought  about  by  the  pressure  produced 
by  the  leverage  obtained  through  the  combination  of  the  operating  lever 
and  the  expansion  of  the  fingers.  Unless  this  pressure  on  the  discs  is 
great  enough,  the  clutch  will  slip  and  heat.  Consequently,  the  discs  will 
be  cut  up  and  their  carrying  power  destroyed,  thus  necessitating  the  pur- 
chase of  new  parts. 


216 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


Remember,  that  every  time  the  clutch  slips  the  plates  become  thinner 
and  further  adjustment  is  necessary  to  take  up  the  wear.  It  is,  there- 
fore, necessary  that  this  adjustment  should  be  obtained  before  the  clutch 
is  allowed  to  run  at  all. 


Yoke  Operating  Type  of  Paragon  Reverse  Gears 


If  the  gear  heats  on.  the  forward  drive  it  indicates  the  gear  is 
ping  and  should  be  adjusted  at  once. 

If  the  gear  slips  on  the  forward  drive,  back  the  set  screw  (76)  out 
of  its  notch  in  the  brass  check  collar  (40).  Turn  the  screw  collar  (28) 
to  the  right  until  the  set  screw  (76)  projects  into  the  next  slot  in  this 
brass  check  collar  (40).  Then  tighten  the  set  screw. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


217 


218  AUXILIARY  MACHINERY  AND  ACCESSORIES 

If  the  gear  still  slips,  back  out  the  set  screw  again  and  turn  the 
screw,  collar  (28)  to  the  right  so  that  the  set  screw  projects  into  another 
notch.  If  it  still  slips,  repeat  the  process  until  the  gear  does  not  slip. 

In  case,  however,  the  adjustment  is  too  tight  after  taking  it  up  one 
of  these  notches,  an  arrangement  is  made  for  taking  up  this  adjustment 
a  half  notch.  To  do  this,  back  the  set  screw  completely  out  of  the  hole 
in  which  it  is  placed  and  insert  it  in  the  other  hole  on  opposite  side  of 
the  screw  collar  (28).  Then  turn  the  collar  to  the  right  until  it  projects 
into  the  next  notch  on  the  brass  check  collar  (40). 

In  all  cases  be  sure  the  set  screw  goes  back  into  one  of  the  notches 
on  the  brass  check  collar. 

The  neutral  position  is  obtained  when  the  operating  lever  is  vertical. 
The  reverse  position  is  obtained  by  means  of  the  brake  band  which 
clamps  around  the  case  and  keeps  it  from  revolving.  The  brake  band  is 
operated  by  throwing  the  lever  back  as  far  as  possible. 


A 

£ 


Friction  Assembly  for  Forward  Drive 


If  the  gear  slips  on  the  reverse,  that  is,  if  the  case  (1)  revolves  when 
the  lever  is  in  reverse  position,  make  adjustment  as  follows,  while  the 
motor  is  running  slowly;  remove  the  cotter  pin  from  the  nut  (51)  at  the 
top  of  the  brake  band  and  tighten  this  nut  until  the  case  ceases  to  re- 
volve, keeping  the  lever  thrown  back  as  far  as  possible.  When  this  is 
done  replace  the  cotter  pin. 

Directions  for  Lubrication:  In  some  motors  the  matter  of  reverse 
gear  lubrication  is  taken  care  of  automatically  by  the  same  lubricating 


AUXILIARY  MACHINER/  AND  ACCESSORIES  219 

system  which  lubricates  the  motor.  In  such  cases,  hand  lubrication  is, 
of  course,  unnecessary. 

When  the  reverse  gear  is  placed  in  an  oil  tight  compartment,  and  a 
splash  system  of  lubrication  is  in  use,  be  sure  that  this  compartment  is 
kept  at  least  half  full  of  a  good  grade  of  lubricating  oil. 

If  neither  of  the  above  lubricating  systems  are  used  in  connection 
with  the  motor,  it  will  be  necessary  to  lubricate  the  gear  by  hand  in  ac- 
cordance with  following  instruction: 

Before  running  the  gear  remove  the  brass  plug  (15)  in  the  case  and 
put  in  non-fluid  oil.  This  is  really  a  grease  instead  of  an  oil  and  is  about 
the  same  consistency,  or  thickness,  as  vaseline.  In  gears  of  larger  sizes 
brass  plug  (15)  will  be  found  on  front  cover. 

After  this  has  been  done,  remove  the  brass  screw  which  is  located 
in  the  case  on  the  other  side  of  the  brake  band.  For  lubrication  here 
pour  in  the  equivalent  of  two  or  three  teaspoonfuls  of  cylinder  oil  which 
is  for  lubricating  the  discs.  While  this  is  being  done  the  lever  should  be 
in  reverse  position  so  that  the  plates  will  be  freed  from  each  other.  Keep 
turning  the  engine  over  by  hand,  or  run  the  engine  slowly  while  injecting 
this  oil.  Oil  the  brass  collar  and  the  disc  (40)  at  the  place  stenciled  "oil". 
Keep  all  grease  cups  filled  and  screw  them  down  as  frequenty  as  neces- 
sity requires  it. 


Gear  Assembly  for  Reverse  Motion 


The  tremendous  explosion  impulses  of  a  slow  turning  oil  motor  de- 
mands a  gear  of  unusual  holding  power.  In  following  illustrations  types 
of  gears  are  shown  adaptable  for  Diesel-powered  marine  engines. 


220 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


In  the  clutch  assembly  of  Model  "H"  illustrated  here,  consisting  of 
five  cast-iron  friction  discs  which  are  ground  for  smoothness.  The  In- 
ternal teeth  of  these  discs  mesh  with  the  external  teeth  of  the  propeller 
gear  hub  as  shown  here.  There  are  also  six  bronze  friction  discs  which 
are  held  in  place  to  the  case  by  twelve  studs.  These  studs  are  distributed 
along  the  circumferences  of  these  discs  and  are  supported  at  both  ends. 


Extra  Heavy  Duty  Type  of  Paragon  Reverse  Gear 


These  eleven  friction  discs  and  their  adjacent  surfaces,  comprising  a 
total  of  24  friction  surfaces,  furnish  a  total  friction  area  of  over  2500 
square  inches.  This  is  one  of  the  reasons  why  this  type  of  Paragon  has 
met  with  such  a  pronounced  success  in  connection  with  powerful  oil- 
burning  motors. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


221 


As  may  be  seen  from  the  illustrations,  the  engine  gear  of  this  model 
is  built  specially  large  and  strong.  The  power  is  transmitted  from  the 
engine  gear  to  the  propeller  gear  through  a  single  train  of  twelve  pinion 
gears,  thus  distributing  the  load  over  an  unusually  large  number  of  in- 
termediary pinions  all  in  one  place. 

The  operating  mechanism  is  of  the  double  incline  lever  type  and  per- 
mits of  the  operating  lever  being  placed  on  either  the  port  or  the  star- 
board side. 


Itemized  Parts  of  Paragon  Reverse  Gear 


222 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


In  maneuvering  of  engine  it  is  imperative  that  reversing  should  be 
accomplished  in  the  quickest  time  possible.  Power  transmission  depend- 
ing upon  the  strong  pulling  capacity  and  reliability  in  service,  calls  for 
strong  and  rigid  built  gears. 

The  motor's  power  in  Paragon  gears  is  transmitted  from  the  engine 
gear  direct  to  the  propeller  gear  through  four  pinions,  each  equi-distant 
from  the  center  and  distributing  the  load  evenly.  This  makes  a  direct 
short  line  for  the  power  to  travel. 

In  some  motors  the  matter  of  reverse  gear  lubrication  is  taken  care 
of  automatically  by  the  same  lubricating  system  which  lubricates  the 
motor.  In  such  cases,  hand  lubrication  is,  of  course,  unnecessary. 

When  the  reverse  gear  is  placed  in  an  oil  tight  compartment,  and  a 
splash  system  of  lubrication  is  in  use,  be  sure  that  this  compartment  is 
kept  at  least  half  full  of  good  grade  of  lubricating  oil. 

If  neither  of  the  above  lubricating  systems  are  used  in  connection 
with  your  motor,  it  will  be  necessary  to  lubricate  gear  by  hand  in  accord- 
ance with  following  instruction:  Before  running  your  gear  remove  the 
brass  plug  in  the  case  and  put  in  non-fluid  oil.  This  is  really  a  grease 
instead  of  an  oil  and  is  of  about  the  same  consistency,  or  thickness,  as 
vaseline.  The  brass  plug  will  be  found  on  the  front  cover. 


DEFINITION  OF  PARTS  OF  PARAGON  REVERSE  GEAR 


1.  Case    assembled    with    Friction 

Disc  Pins  No.  9  and  Oil  Plugs 
No.   15. 

2.  Cover     assembled     with     Cover 

Bushing     No.     6     and     Pinion 
Studs  No.  8. 

3.  Propeller  Gear. 

45.  Propeller  Gear  Hub. 

4.  Engine  Gear. 

5.  Pinion     Gear     assembled     with 

Pinion  Bushing  No.   7. 

10.  Friction  Disc. 

11.  Finger  Disc. 
21.  Fingers. 

61.  Toggle  Link. 
16.  Finger  Pin. 
63.  Toggle  Link  Pin. 
94.  Cone  Stops. 
18.  Toggle  Collar. 
19-20.  Brake   Band. 

23.  Pinion  Support. 

24.  Lever. 

187.  Lever  Set  Screw. 

56.  Woodruff  Key  for  Lever. 


26.  Locking  Link. 
28-76.  Screw  Collar. 

76.  Screw  Collar  Cap  Screw. 
29.  Finger  Collar. 

37.  Friction  Disc. 
40.  Check  Collar. 
44.  Check  Collar  Dogs. 

50.  Locking  Link  Bracket  Screw 

51.  Castellated  Nut. 
53.  Hexagon  Nut. 
55.  Grease  Cup. 

60.  Toggle  Sleeve. 

62.  Toggle  iSleeve  Pin. 

70.  Cover  Cap  Screw. 

77.  Engine   Gear   Set    Screw. 
80.  Spring  Cotter. 

87.  Adjusting  Belt. 
111.  Yoke  assembled. 
180.  Yoke  Shaft  Brackets. 
30-32.  Rear  Bearing. 
31.  Thrust  Bearing. 

33.  Thrust  Collar. 

34.  Thrust  Collar  Set  Screw. 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


223 


In  following  illustrations,  showing  detailed  parts  of  the  Johnson- 
Carlyle  type  of  friction  clutch,  a  clear  idea  will  be  obtained  as  to  the  dis- 
tinctive feature  of  this  reverse  gear.  The  illustration,  figure  a.,  shows 
in  perspective  a  nest  of  spur  gearing,  incorporated  within  a  clutch  body 
or  gear  cage,  on  each  end  of  which  are  mounted  clutch  members  of  the 
Johnson  type  of  clutch.  These  gears  run  on  four  hardened  shafts,  each 
end  of  which  are  supported  in  the  ends  of  the  gear  cage.  The  gears  are 
always  in  mesh  with  the  engine  and  propeller  shaft  pinions,  as  shown, 
and  the  former  .extends  to  the  right  and  the  latter  to  the  left,  each  being 
supported!  in  babbitt  bearings  in  the  ends  of  the  gear  cage  and  extending 
through  far  enough  to  be  coupled  onto. 


Fig.  (a).   Double  Clutch  Gear  Cage  Perspective 


The  gearing  and  shafting  are  small  in  diameter,  in  order  to  keep  the 
construction  compact,,  but  are  made  of  alloy  steel,  heat  treated  and  hard- 
ened, thus  giving  these  parts  the  strength  of  a  cast-iron  or  machine  steel 
gear  several  times  as  large. 

The  expanding  friction  rings,  figure  b.,  are  shown  one  on  each  of 
the  gear  cage,  with  a  set  of  toggle  levers  in  each,  diametrically  opposite, 
for  use  in  expanding  same.  In  the  friction  cups  in  which  these  rings  ex- 
pand, surrounding  the  rings  are  placed  in  such  position  to  take  up  all 
leverage  required  of  the  same. 


Fig.   (&).    Double  Clutch,  Gear  Cage 

Spaced  midway  on  the  clutch  body  is  the  shipper  sleeve  with  two 
hardened  curve-shaped  wedges  riveted  in  it.  These  wedges  force  the  lev- 
ers apart,  thus  expanding  the  rings,  bringing  their  outer  surfaces  into 
frictional  contact  with  the  inner  surface  of  the  friction  cups. 


224 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


The  leverage  is  so  compounded  that  it  requires  but  little  pressure 
to  operate  the  clutches.  The  adjustment  is  very  simple,  as  one  screw 
which  moves  two  taper  blocks  ,set  into  the  base  of  the  toggle  levers  ad- 
justs the  contact  of  each  ring  and  cup  to  any  tension.  This  screw  is 
easily  reached  with  a  screw  driver  through  a  hole  in  the  reverse  gear 
cover  and  friction  cup. 


Propeller  End 


Fig.  (c).  Exterior  View 


Engine  End 


In  the  double-clutch  construction  the  hub  on  the  friction  cup  is 
clamped  on  its  outside  diameter  within  the  cases  and  contains  a  combined 
radial  and  double  thrust  ball  bearing,  through  which  the  propeller  shaft 
runs.  The  hub  of  the  other  friction  cup  is  free  to  revolve  in  the  casing, 
within  a  radial  ball  bearing,  while  the  engine  shaft  of  the  gear  extends 
through  it  and  is  keyed  therein. 


AUXILIARY  MACHINERY  AND  ACCESSORIES  225 

Adjustment:  The  forward  drive  clutch  can  'be  adjusted  independent 
of  the  reverse  drive  clutch.  If  either  forward  or  reverse  clutch  shows 
any  tendency  to  slip,  it  should  be  adjusted  -at  once. 

As  there  are  only  two  points  of  adjustment  in;  this  gear,  the  opera- 
tor  will  have  the  minimum  amount  of  trouble  if  the  clutches  are  kept 
adjusted  to  a  tension  where  they  will  not  slip,  provided  the  gear  is  being 
used  for  power  within  its  rating. 

To  adjust  the  engine  and  clutch,  remove  the  thumb  nut  nearest  to  the 
engine,  on  the  top  of  the  reverse  gear  case,  turn  the  engine  and  shaft 
until  the  hole  in  the  friction  cup  comes  into  view,  then  turn  propeller 
end  shaft  until  adjusting  screw  appears  under  hole  in  friction  cup.  With 
a  screwdriver  with  a  fine  point  turn  the  screw  a  fraction  of  a  turn,  or 
more  if  necessary,  to  the  right  to  tighten,  to  the  left  to  loosen.  To  ad- 
just the  propeller  end  clutch,  remove  the  other  thumb  nut,  and  turn  the 
propeller  shaft  until  the  adjusting  screw  appears  through  'hole  in  fric- 
tion cup,  this  latter  being  stationary  on  this  end  of  gear.  Adjust  as 
above. 

Lubrication:  The  lubrication  automatically  takes  care  of  itself 
if  the  gear  case  is  supplied  several  times  during  the  season.  (Fill  about 
one-half  full). 

Do  not  run;  the  gear  without  sufficient  lubricant  in  the  case.  A  grav- 
ity system  of  lubrication  leads  to  all  bearings  in  the  gear. 

To  fill  the  case,  remove  the  two  thumb  nuts  on  the  top  cover  and  oil 
or  grease  can  be  put  in  at  these  points.  Do  not  use  a  'hard,  heavy  grease, 
as  the  design  of  these  gears  is  such  as  to  require  a  medium  heavy  oil  or 
grease.  The  oil  shedders  on  the  inside  of  each  end  of  the  gear  case  pre- 
vent the  lubricant  from  working  out. 


ELECTRICAL     AUXILIARIES 

As  a  result  of  the  us©  of  electric  motors  on  Diesel  engine-driven  ves- 
sels and  their  longer  and  extensive  use  in  the  navy,  the  marked  advan- 
tages of  motor-driven  auxiliaries  are  now  recognized  as  never  before. 

The  adoption  of  electric  drive  for  auxiliary  machinery  is  bound  to  in- 
crease on  vessels  propelled  by  internal  combustion  engines,  in  particular 
larger  types  intended  for  long  voyages.  In  the  many  large  Diesel-pro- 
pelled ships,  where  electric  steering  gears  have  been  in  use  as  well  as 
winches,  it  has  proven  an  exceeding  reliable  and  above  all  economizing 
factor.  There  are  numerous  other  advantages  in  using  electrical  equip- 
ment in  conjunction  with  Diesel  power,  which  we  will  undertake  here 
to  summarize  as  a  few  worthy  of  mention: 

(1).  Comparative  little  expenses  in  maintainance. 

(2).  More  reliable  speed  control  is  obtained. 

(3).  Better  methods  of  control. 

(4).  Electric  power  consumption  can  be  accurately  measured. 

(5).  Electric  power  use  is  cleaner  and  quieter  than  other  powers, 


226 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


Reasons  given  here  could  be  followed  up  with  numerous  others,  but 
they  are  sufficiently  convincing  to  show  to  the  most  skeptic  that  with 
the  introduction  of  electrical  units  a  great  many  advantages  may  be  ob- 
tained. Motors  require  much  less  labor  expense  than  engines.  One  man 
can  usually  look  after  many  motors,  but  cannot  properly  handle  more 
than  one  engine  under  the  same  conditions. 

Modern  marine  electrical  equipment  is  designed  for  the  most  part, 
for  230-volt  service.  Several  years  ago  the  U.  S.  Navy  Department  adopted 
this  voltage  for  practically  all  capital  ships.  The  use  of  this  higher  volt- 
age has  decreased  the  size  of  generating  equipment,  motors,  and  wiring, 
as  compared,  with  that  which  was  required  with  the  low  voltage  systems 
used  in  the  early  days.  The  higher  voltage  has,  at  the  same  time,  been 
found  just  as  satisfactory  from  an  operating  standpoint. 


A  view  of  the  engine  room  switch  board  on  the  motorship,   "Solitaire," 
showing  the  circuit  breakers  and  several  of  the  G-H  Mag- 
netic Contactors,  by  means  of  which  the  en- 
gine room  auxiliaries  arc   controlled. 

Marine  control  equipment  for  motor-driven  auxiliaries  must  be 
adapted  for  the  conditions  found  on  board  ship  in  order  to  insure  satis- 
factory operation.  As  a  rule,  the  characteristics  of  marine  controllers 
differ  from  similar  equipment  used  on  land.  Early  failures  of  electric 
drive  in  marine  service  were  traceable  to  equipment  that  was  manufac- 
tured primarily  for  use  on  land  or  that  was  designed  by  those  who  were 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


227 


unfamiliar  with  the  actual  requirements  of  marine  service.  Illustrations 
shown  here  are  products  of  the  Cutler-Hammer  Company  of  Milwaukee, 
which  firm  has  added  many  late  features  commendable  for  Diesel-pow- 
ered ships  where  electrical  equipment  is  called)  for. 

Marine  control  equipment  should,  generally  speaking,  be  constructed 
along  more  rugged  lines  and  should  have  a  larger  factor  of  safety  than  is 
necessary  for  similar  equipment  used  in  other  industries.  Repairs  are 
not  as  easily  made  in  the  marine  service  as  on  land.  Consequently,  marine 
controllers  must  be  capable  of  withstanding  rough  handling  by  inexper- 
ienced men  with  a  minimum  of  maintainance  expense. 


C-H  Water-tight  Rheostat  (same  as  shown  at  left)  with  upper  and  lower 
covers   open  for  ventilation.       The  front  cover  also   has   been  re- 
moved to  show  the  resistor  units.      This  cover  is  not  removed 
after  installation  except  for  occasional  inspection. 


All  marine  controllers  should  be  made  as  simple  as  possible  to  facili- 
tate maintainance  work  and  the  prompt  location  of  trouble.  All  parts 
must. be  carefully  protected  from  salt  air  and  moisture  conditions,  and 
controllers  used  on  deck  or  where  subject  to  possible  water  pressure  must 
be  made  water-tight.  For  certain  navy  uses  and  fon  use  on  the  merchant 
marine  where  inflammable  liquids  or  gases  may  be  present,  gas-tight  con- 


228  AUXILIARY  MACHINERY  AND  ACCESSORIES 

trollers  are  made  specially  for  this  service.  Controllers  used  with  cer- 
tain auxiliaries  are  so  constructed  that  unauthorized  manipulations  are 
impossible. 

Automatic  controllers  used  on  board  ship  are  provided  with  con- 
tactors which  cannot  close  accidentally  due  to  the  rolling  of  the  ship  or 
open  because  of  violent  shock.  All  contactors  must  usually  operate  sat- 
isfactorily when  inclined  at  an  angle  of  30  degrees  from  the  vertical  in 
any  direction.  All  contactors  used  in  marine  service  are  subject  to  more 
or  less  vibration  and  should  be  protected  from  the  loosening  of  parts  by 
suitable  locking  pins  or  nuts. 


•% 


C-H  Master  Switch  of  the  type   used  for  operating  small  steering  gear 
controllers  like  the  one  shown  above.      Cover  removed. 

Resisters  used  with  marine  controllers  must  be  carefully  protected 
from  corrosion  and  from  damage  by  shock  or  vibration.  Some  resistors 
are  used  where  the  ventilation  is  restricted  and  in  such  cases  correct 
design  is  very  essential.  Resistors  used  on  deck  where  they  may  be  sub- 
jected to  immersion  are  protected  by  water-tight  enclosures  so  arranged 
that  they  may  be  opened  for  ventilation  when  in  actual  operation.  Re- 
sistors used  in  marine  service  are  usually  built  up  in  such  a  way  that 
single  resistance  units  may  be  replaced  readily,  if  damaged. 

Other  requirements,  which  are  peculiar  to  marine  control  equipment 
and  which  are  necessary  to  the  successful  operation  of  motor-driven  aux- 
iliaries, might  be  mentioned.  Those  already  outlined  in  previous  pages 
will  serve  to  indicate  the  necessity  for  studying  the  actual  conditions  on 
board  ship  before  designing  marine  controllers  and  such  apparatus  im- 
perative in  general  operation. 

Illustrations  shown  here  of  the  motorship  ".Solitaire",  a  steel  tanker 
of  6730  tons  displacement,  launched  in  1920  at  Bath,  Maine,  is  an  excel- 
lent example  of  the  new  American  merchant  marine.  The  auxiliaries  are 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


229 


all  motor-driven.  Engine  room  auxiliaries  are  controlled  from  a  cen- 
tralized point.  The  electrician  on  watch  is  responsible  for  starting  the 
various  pumps,  etc.,  when  signalled  by  bell  and  pilot  light  from  the  unit 
to  be  started.  The  signal  is  given  by  pressing  a  push  button  afc  the  aux- 
iliary; it  continues  until  the  electrician  closes  the  line  circuit  breakers. 
The  auxiliary  motor  may  be  stopped  automatically  by  pushing  the  stop 
button  located  nearby. 


I 
§1 


•1 8 


*s? 

^     **     r2 

S"     O 


|      ° 
'?      I 


^-*    r^ 

'o 


-^  ** 


c> 


After  the  line  circuit  breakers  are  closed,  the  motor  is  accelerated 
automatically  through  magnetic  lockout  contactors  which  quickly  bring 
the  auxiliary  up  to  speed.  The  motors  are  thus  protected  from  injury 
due  to  improper  handling  and  manipulation  by  inexperienced  operators. 


230 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


The  deck  auxiliaries  on  the  motorship  "Solitaire"  are  handled  through 
manually-operated  controllers  from  stations  convenient  to  auxiliaries.  The 
capstan  motor  is  controlled  by  means  of  a  drum  controller  located  on  a 
bulkhead  below  deck.  The  drum  controller  is  fitted  with  a  shaft  which 
extends  up  through  the  deck  and  on  the  to>p  of  which  is  an  operating  han- 
dle. This  handle  is  located  adjacent  to  the  capstan  barrel  so  that  the 
operator  has  an  unobstructed  view  of  what  is  goimg  on.  The  deck  winch 
is  controlled  by  a  water-tight  drum  controller  located  where  the  opera 
tor  has  a  clear  view  of  the  winch. 


C-H  Automatic   Steering   Gear  Controller  of  the   type  used  on   merchant 

vessels.       This  controller  is  installed  below   deck  and  is  operated 

from  a  master  switch  similar  to  the  one  illustrated  below. 


In  addition  to  the  electrical  control  equipment  found  on  the  "Soli- 
taire", electric  heaters  are  used  for  heating  the  quarters  of  the  officers 
and  crew.  Electric  heating  eliminates  all  other  provisions  necessary  to 
heat  the  living  quarters  of  the  ship  in  colder  climates.  Three  heats — 
low,,  medium  and  high — are  provided,  thus  insuring  comfortable  quarters 
under  all  weather  conditions. 

Electric  current,  being  easily  transmitted,  is  not  subjected  to  losses 
as  in  the  case  where  Diesel-powered  ships  have  steam  auxiliaries  in  con- 
junction and  through  condensation  and  latent  losses  extravagance  is 
bound  to  occur.  A  saving  in  space  and  weight  is  made;  greater  flexibility 
and  ease  of  control  are  effected.  Where  once  the  operating  engineers  have 
sufficient  training  in  electrical  matters  (which  is  a  requirement  not  to 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


231 


be  overlooked)  repairs,  adjustments  and  maintainance,  can  be  cared  for 
more  easily  than  similar  work  in  connection  with  other  powers. 

It  is  a  well  known  fact  to  all  familiar  with  the  running  of  ships,  that 
sometimes  more  care  is  necessary  and  more  trouble  caused  in  keeping 
the  auxiliary  machinery  than  the  main  engines  of  a  vessel  in  working 
condition.  The  consumption  of  power  for  running  the  auxiliaries  is  also 
very  large  because,  as  a  rule,  these  auxiliaries  are  driven  by  direct-con- 
nected engines  of  a  simple  and  poor  construction!  working  at  tfull  admis- 
sion; besides,  a  considerable  loss  of  power  is  due  to  the  extensive  net  of 
piping. 

Of  late,  endeavors  have  been  made  to  remedy  this  'trouble  by  introduc- 
ing in  first-class  modern  vessels,  winches  and  steering  gear  worked  by 
electricity. 


Motor-driven   Cargo  Winch  equipped  with  a  C-H  Drum  Controller.    The 
drum  and  resistor  are,  mounted  in  the  water-tight  base,  the  front 
cover  of  which  has  been  removed  to  show  the  drum.      The  arc 
shields  have  also  been  swung  back.    The  resistor  is  installed 
in  the  far  end  of  the  base  where  hand  wheels,  shown 
on  the  lower  right  hand  side  of  the  illustration, 
permit  the  opening  of  base  covers  for  ventila- 
tion   while    the   motor   is    operating. 

The  designing  of  all  auxiliary  machinery  of  Diesel  vessels  for  elec- 
trical power  is  very  desirable  and  this  method  is  being  brought  in  prac- 
tice by  many  builders  of  Diesel  machinery. 


232 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


233 


The  power  is  supplied  by  auxiliary  Diesel  engines,  installed  along 
the  side  of  the  engine  room  and  directly  coupled  to  continuous  dynamos 
from  which  the  current  is  conducted  -to  a  switchboard  and  thence  to  all 
the  auxiliaries  of  the  vessel.  The  auxiliary  Diesel  engine  system  is  car- 
ried out  in  quite  a  special  manner  dimensioned  to  suit  the  requirements 
on  board,  so  that  under  all  conditions  full  certainty  is  attained  of  having 
at  any  time  at  disposal  the  necessary  current,  which  affords  the  absolute 
reliability  required.  The  fact  is  that  the  absolute  certainty  of  current 
always  being  at  hand  is  a  condition  necessary  for  the  system  operating 
in  a  perfectly  satisfactory  manner,  seeing  that  the  working  of  an  auxili- 
ary of  such  importance  as  the  steering  gear  depends  thereon.  The  aux- 
iliary engines  are  thus  dimensioned  that  they  are  partly  able  to  generate 
the  current  required  for  working  all  the  loading  and  discharging  winches 
in  port,  and  partly  for  generating  the  smaller  amount  of  current  required 
for  keeping  the  auxiliary  engines  of  the  vessel  running. 

The  main  engines  of  the  vessel  are  self-contained,  the  pumps  being 
worked  independently. 

Electrical  driven  machinery  run  by  dynamos  and  worked  by  auxiliary 
Diesel  engines  affords  a  high  degree  of  economy,  as  the  consumption  of 
fuel  oil  for  running  all  the  auxiliaries  of  the  vessel  at  sea  amounts  only 
to  a  few  per  cent  of  the  consumption  of  fuel  oil  for  running  the  main 
engines,  and  the  electrical  power  required  for  running  the  loading 
and  discharging  winches  in  port  is  performed  with  a  consumption  of  only 
one-tenth  part  of  that  necessary  for  steam-driven  winches. 

The  electric  cables  are  easily  and  suitably  laid  from  one  end  of  the 
vessel  to  the  other  and  do  not  require  the  space  or  attendance  required 
by  the  pipes. 

On  land  electric  transmission  of  power  has,  by  degrees,  superseded 
all  other  systems  of  transmission;  it  is  therefore  quite  natural  that  also 
on  board  ship  electric  transmission  will  displace  all  other  systems  of 
transmission,  the  electric  machinery  must  of  course  be  designed  specially 


Diagramatical  View  of  Worthington  Diesel  Engines,  Suitable  for 
Auxiliary  Purposes 


234 


AUXILIARY  MACHINERY  AND  ACCESSORIES 


for  marine  purpose,  heavy  and  strong,  with  motors,  controllers,  etc.,  of 
the  water-tight  enclosed  type;  the  motors  supplied  for  this  purpose  must 
be  of  the  best  material  suitable  for  this  service. 

Steam-driven  and  distillate-driven  auxiliaries  have  been  found  to  have 
certain  disadvantages  on  board  the  full-powered  Diesel  mortorships.  The 
boilers  used  in  connection  with  the  steam-driven  auxiliaries  have  given 
no  end  of  trouble  and  annoyance,  and  when  small  distillate  engines  are 
used,  the  necessity  of  carrying  two  kinds  of  fuel  (crude  oil  for  the  main 
engines  and  distillate  for  the  auxiliaries)  when  storage  space  is  at  a 
premium,  is  a  decided  drawback. 

In  accompanying  illustration,  the  diagram  shows  a  general  arrange- 
ment of  system  adopted  by  the  Dow  Diesel  Engine  Company  in  the  plants 
constructed  by  this  firm.  These  specially  constructed  Diesel  engines  are 
direct-connected  to  electric  generators,  which  in  turn  supply  the  power 
for  all  loading  and  unloading  purposes,  light,  etc. 

As  will  be  seen  in  this  diagram,  the  Dow  Full  Diesel  Type  Crude  Oil 
Engines  direct-connected  to  electric  generator  is  a  compact,  self-contained 
unit. 


Plan  View  of  Dow  Diesel  Engines,  Direct  Connected  to  Electric  Motors 


DESCRIPTION  OF  DIESEL  ENGINES 


235 


The  accompanying  illustration  shows  a  Allan-Cunningham  Hydrau- 
lic Electric  Steering  Gear.  This  machine  has  been  specially  developed  for 
use  on  marine  service  of  Diesel-powered  ships.  The  machine  is  equipped 
with  hydraulic  telemotor  control,  directly  operated  from  the  Wheel  House. 


In  this  machine  a  constant  speed,  continuously  running  electric  motor 
furnishes  the  power  to  operate  a  spring  quadrant  mounted  on  the  rudder 
stock,  and  this  is  applied  through  a  hydraulic  variable  speed  gear,  whose 
speed  and  direction  are  controlled  by  means  of  the  hydraulic  telemotor 


236 


AUXILIARY   MACHINERY  AND  ACCESSORIES 


system  from  the  wheel  house.  Follow  up  gear  is  provided  so  that  the  rud- 
der movement  follows  closely  the  direction  and  amount  of  movement  of 
the  wheel  by  the  man  steering.  Its  reliability  is  primarily  due  to  the 
accurate  close  mesh  gears  which  quickly  correspond  to  the  movements  of 
the  ship. 

The  Allan-Cunningham  type  of  electric  Anchor-Windlass  is  shown  in 
the  accompanying  illustration.  The  anchor  windlass  is  a  piece  of  equip- 
ment that  is  not  often  put  to  use  on  board  ship,  but  when  it  is  called  upon 
for  service,  needs  to  perform  some  very  severe  duties  for  a  short  time, 
or  withstand  some  very  heavy  labor.  For  this  reason  ruggedness  and 
strength  of  all  the  parts  should  be  its  principal  characteristic,  as  shown 
in  the  illustration,  where  a  marine  type  series  motor  is  geared  through 
spur  gears,  worm  and  worm  gear  to  an  intermediate  shaft  on  which  are 
mounted  the  gypsy  heads  for  use  in  warping  ship.  The  intermediate  shaft 
carries  two  sliding  pinions  for  meshing  with  the  main  gears  on  each 


Allan-Cunningham  Electrically  Operated  Anchor-Windlass — Specially 
Constructed  for  Diesel-powered  Ships 

wildcat.  A  clutch-shifting  device  provides  for  throwing  the  wildcats  in  or 
out  of  gear,  and  band  brakes  can  be  used  to  hold  them  in  any  position 
desired. 

A  machine  of  this  type  is  very  rugged  and  capable  of  exerting  an 
enormous  pull,  cases  being  known  where  a  25  H.  P.  windlass  like  this 
has  pulled  a  2-inch  steel  anchor  chain  in  two  without  damage  to  itself. 
Straight  rheostatic  control  with  overload  protective  devices  is  nearly 
always  used,  and  in  this  case  is  all  installed  in  the  hollow  base  and  cast 
iron  box,  making  the  machine  a  complete  self-contained  unit. 

Allan-Cunningham's  Cargo  Winches,  as  illustrated  in  cut,  are  carefully 


AUXILIARY   MACHINERY  AND  ACCESSORIES 


237 


designed  to  correspond  with  the  extra  heavy  work  required  of  a  machine 
of  this  kind.  The  service  requirements  of  the  cargo  winch  are  very  severe, 
as  they  not  only  have  to  stand  up  to  severe  labor  when  loading  or  un- 
loading ship,  but  must  withstand  all  sorts  of  weather  conditions,  from 
excessive  heat  to  deluges  of  salt  water.  For  moderate  sizes,  the  hollow 
base  type  shown  is  a  great  favorite,  consisting  of  a  series  motor  with 
magnetic  disc  brake  spur  igeared  through  pinion,  intermediate  shaft  to 
main  gear  bolted  to  the  drum,  with  dynamic  lowering  controller  and  re- 
sistors mounted  in  tihe  base.  The  base  is  made  thoroughly  watertight  and 
ventilating  doors  are  provided  for  use  when  the  winch  is  operating. 


Typical  Allan-Cunningham  Cargo  Winch 


238 


2 


CHAPTER  X. 

DESCRIPTION     OF     DIESEL     ENGINES 
BUSCH-SULZER    MARINE    DIESELS 

The  Bulsch-Sulzer  Engine  Company  of  St.  Louis,  Mo.  was  the 
original,  and  from  1898  to  1911  the  only  American  Manufacturer  of  Diesel 
Engines.  Their  23  years  of  Diesel  building  and  their  partnership  af- 
filiation with  the  well  known  iSwiss  firm,  Sulzer  iFreres  of  Winterthur. 
Switzerland,  places  them  first  among  the  best  known  American  Builders 
01  Diesel  Engines. 

In  following  explanation  of  this  well  known  engine  a  clear  con- 
ception will  be  gained  on  maintenance  and  operation  of  Diesels,  in 
particular  the  two-cycle  constructed. 

The  engine  utilizes,  directly  in  its  cylinders,  any  heavy  liquid  fuel 
ranging  from  kerosene  to  coal  tar. 

Pure  air,  with  which  the  engine  cylinder  is  filled,  is  compressed 
by  the  upward-traveling  piston  to  a  pressure  of  450  to  500  pounds. 
Its  temperature  Increases,  due  to  this  compression,  to  approximately 
1,000  degrees  Fahrenheit.  At  or  near  the  upper  dead-center  of  the 
piston  the  fuel  is  sprayed  into  the  cylinder,  gradually  and  in  a  finely 
nebulized  condition.  The  fuel  is  gasified  and  ignited  by  the  heat  of  the 
compressed  air,  without  any  supplementary  means;  it  burns  during  the 
first  part  of  the  piston  down--stroke,  after  which  the  hot  gases  in  the 
cylinder  continue  to  expand  and  perform  work  on  the  piston,  until  they 
are  exhausted  from  the  cylinder. 

The  rate  at  which  the  fuel  is  injected  into  the  cylinder  is  so  ad- 
justed that  its  ignition  and  combustion  takes  place  without  explosive 
violence,  and  with  substantially  no  change  of  pressure;  for  which 
reason  this  type  of  engine  is  sometimes  referred  to  as  "Constant 
pressure"  tyipe,  to  distinguish  it  from  the  "Constant  volume"  type,  such 
as  gas,  gasoline,  and  hot  bulb  engines,  and  engines  improperly  desig- 
nated "Semi-Diesel,"  in  which  combustion  takes  place  substantially  with- 
out increase  in  volume,  and  therefore  with  an  explosive-like  increase  in 
pressure. 

Diesel  engines  are  built  to  operate  on  either  the  four-stroke  cycle 
(briefly,  "four-cycle"),  or  the  two-stroke  cycle  (briefly  "two-cycle") 
system. 

In  a  four-cycle  engine,  four  strokes  of  the  piston,  or  two  revolutions 
of  the  crankshaft,  are  required  to  complete  the  cycle  of  operations. 
These  operations  are  illustrated  in  Figures — I  (a)  to  (d),  each  of  which 
is  accompanied  by  a  description. 


240 


RIPTIOX  OF  DIESEL  ENGINES 


Figure  f. 


(a)  First  stroke  (.ad- 
mission stroke).  Pis- 
ton travels  down;  ad- 
mission valve  open; 
cylinder  is  being  Ailed 
•with  pure  air. 


(fr)  Second  stroke 
{compression  stroke). 
Piston  travels  up;  all 
valves  closed;  air  in 
cylinder  is  being  com- 
pressed. 


(c)  Third  stroke 
(power  stroke).  Pis- 
ton travels  down;  fuel 
valve  open  at  top 
dead-center,  but  closed 
at  fraction  of  stroke; 
gases  expand. 


(</)  Piston  travel 
ing  up;  piston  cov- 
ers exhaust  ports; 
scavenging  v  al  v  e 
closed;  air  in  cyl- 
inder is  being  com- 
pressed. 


I 

Figure  2. 

Figure — 2  shows  a  typical  indicator  diagram  from  a  four-cycle 
Diesel  Engine,  on  which  diagram  the  lines  representing  the  various 
operations  are  lettered  to  agree  with  Figure — 2.  The  constant  pres- 
sure combustion,  which  is  unique  in  the  Diesel  engine,  is  obvious  from 
this  diagram. 

In  a  two-cycle  engine,  two  strokes  of  the  piston,  or  one  revolution 
of  the  crankshaft,  are  required  to  complete  the  cycle  of  operation. 
These  operations  are  illustrated  in  Figures  3  (a)  to  (d),  each  of  which 
is  accompanied  by  a  description.. 

In  the  selection  of  engines  for  the  propulsion  of  ships,  there  are 
practical  points  which  must  be  considered,  namely  Reliability  and  Sim- 
plicity, Economy  in  Operation,  Ease  of  Operation,  Accessibility  and  Eas<4 
of  Repair,  Space  Requirements,  and  Weight. 

The  most  important  elements  which  effect  the  Reliability  of  a 
Diesel  engine  are  the  combustion  space  in  the  working  cylinder,  and  the 
parts  which  surround  this  space.  Very  high  temperatures  occur  in 
this  space,  necessitating  that  the  surrounding  parts  be  so  constructed 
that  excessive  heat  stresses  will  be  avoided.  This  is  a  compratively 
simple  problem  in  the  case  of  such  parts  as  the  cylinder  liner  and  piston 
as  these  are  of  symmetrical  circular  form  which  expand  uniformly;  but 
it  is  much  more  difficult  in  the  case  of  the  cylinder  heads  which  must 
contain  valve  ports  or  openings.  A  head  with  more  than  one  open- 
ing is  not  symmetrical  and  the  increase  of  the  quantity  of  such  open- 
ings increases  the  difficulty  of  casting  the  head  without  shrinkage 
stress.  Increasing  the  number  of  the  openings  also  increases  the 
difficulty  of  cooling,  resulting  in  failure  of  uneven  expansion. 


RIPTIOX  OF  DIESEL  ENGINES 


Piston    treapeKng 


fmtl  in-  exhaust  ports;  burnt  stitt  uncovered;  scaaf- 
jected  and  burnt  dur-  gases  escape  through  emging  valves  open; 
ing  firs*  part  of  exhaust  ports,  redmc-  air  under  Kght  pres- 
stroke;  gases  expand,  ing  their  pressure  to  smre  enters  through 

scavenging  vetoes,  and 
bloms  gases  out  of 
cylinder. 


~  .  -.-'-,  ::-...• 
ifjrh*mst  stroke). 
Pistam  travels  «/>; 
ejchaxst  r«fr*  op- 
m;  burnt  gases  are 
ejcpflled  from  cyl- 


Fiffmrc  4  shoirs  a  typical  indicator  diagram  from  an  ordinary  two-cycie 

Diesel  Engine. 


shows  &  sectional  plan  and  elevation  of  the  Busch-Sulzer 
two-cycle  cylinder  head  and  the  same  views  of  an  equivalent  four-cycle 
cylinder  head  of  modern  design.  It  is  obvious  from  this  diagram  that 
the  two-cycle  cylinder  head  can  safely  withstand  higher  temperatures 
and  the  engine  may  therefore,  without  sacrifice  of  reliability,  operate 
continuous  with  higher  mean  pressure  than  any  engine  having  numerous 
valves  in  its  head. 

The  principal  elements  effecting  Economy   in    the   operation    of   a 
Diesel  engine  are:  the  cost  of  the  fuel,  the  quantity  of  fuel  consumed, 
and  the  cost  of  maintaining  the  engine  in  operation. 

In  the  case  of  stationary  engines  of  small  and  medium  capacities, 
which  can  be  built  on  the  four-cycle  system  without  incurring  ser- 
ious risks  of  breakdown,  it  is  cheaper  to  use  a  good  grade  of  fuel  which 
can  readily  be  obtained  in  the  small  quantities  required  by  such  en- 
gines, than  to  incur  the  greater  labor  expenses  of  removing  the  de- 
posits formed  by  cheaper,  low-grade  fuels,  and  correcting  the  other 
detrimental  effects  of  such  fuels. 

In  the  case  of  large  engines  for  marine  uses,  it  not  only  is  cheaper 
but  may  also  be  absolutely  necessary  to  operate  with  low-grade  fuels, 
the  first  cost  of  which  is  lower  than  that  of  higher  grades  where  both 
are  obtainable,  while  they  can  be  obtained  in  the  required  quantity  in 


242 


DESCRIPTION  OF  DIESEL  ENGINES 


localities  in  which  it  would  be  difficult  or  impossible  'to  get  the  higher 
grade  at  any  price.  For  such  engines  the  ability  to  use  a  low-grade  fuel 
is,  therefore,  of  primary  importance,  and  in  this  respect  the  advantage 
of  the  two-cycle  engine  cannot  be  questioned. 

The  absence  of  exhaust  valves,  which  would  be  gummed  up  by  as- 
phaltum,  and  destroyed  by  'sulphur,  make  it  possible  to  successfully 
operate  the  two-cycle  Diesel  engines  with  poor  grades  of  oil  fuel  obtain- 
able in  almost  any  quarter  of  the  globe  and  at  low  prices. 

Although  Ease  of  Operation  is  important  under  all  circumstances, 
it  applies  with  special  force  to  marine  engines,  in  which  it  is  essential 
that  starting  and  reversing  be  accomplished  with  ease,  rapidity,  and 
absolute  certainty. 

The  starting  of  a  marine  engine  must  be  possible  and  sure  with 
any  and  all  positions  of  'the  cranks.  To  accomplish  .this  at  all  a  four- 


Flgure  5. 


Two-Cycle 

(Busch-Sulzer  Diesel) 
Cylinder  Head 


Four-Cycle 

( Standard  Construction) , 
Cylinder  Head 


cycle  engine  must  have  at  least  six  cylinders;  while  a  four  cylinder 
two-cycle  engine  has  a  starting  facility  equal  to  that  of  an  eight  cylinder 
four-cycle. 

To  reverse  the  two-cycle  requires  the  maneuvering  of  only  the  light 
starting  and  fuel  valve  and  gears;  while  the  four-cycle  requires,  in  ad- 
dition to  this  the  maneuvering  of  the  relatively  massive  and  heavily 
spring-loaded  admission  and  exhaust  valves  and  gears.  All  moving 
parts — pistons,  connecting  rods,  crankshafts,  flywheel,  and  line-shafting — 
which  must  be  brought  to  rest,  restarted,  and  accelerated,  are  much 
lighter  in  the  two-cycle. 

The  more  favorable  conditions  of  crank  angle,  weight  to  be  handled, 
and  resistance  to  be  overcome,  of  the  two-cycle  minimize  the  dangers 
of  false  starts  in  either  direction,  and  of  slowness  in  the  handling  of 
the  ship. 


DESCRIPTION  OF  DIESEL  ENGINES  243 

In  ability  to  carry  overloads,  also,  the  two-cycle  has  the  advantage 
over  the  four-cycle.  Overloads  are  emergency  requirements,  purchased 
at  the  price  of  imperfect  fuel  combustion,  and  the  consequent  deposit 
of  carbon  in  the  combustion  spaces.  Such  deposits  cause  more  trouble 
with  the  exhaust  valves  of  a  four-cycle,  than  with  any  other  part  of 
either  system  of  engine. 

Unfortunately,  every  machine  is  liable  to  mishaps,  and  it  is  im- 
portant that  parts  injured  by  such  mishaps  may  be  quickly  repaired 
or  replaced.  Correct  methods  of  manufacture  insure  interchangeability, 
and  correct  designs  Accesibility ;  the  other  factors  which  effect  replace- 
ments are  simplicity  and  ease  of  demounting  and  reassembling. 

Comparing  a  four-cycle  engine  with  the  two-cycle,  it  will  be  found 
that  the  cylinder  head  of  the  four-cycle  has  fuel,  starting  admission,  and 
exhaust  valves  and  their  cages  mounted  on  it,  and  bulky  admission  and 
exhaust  headers  attached  ,to  it,  in  addition  to  the  small  fuel,  starting  air, 
and  water  piping;  whereas  the  cylinder  head  of  the  Busch-Sulzer  two- 
cycle  type  has  only  the  fuel  and  starting  valves  and  their  combine  cage 
mounted  on  it,  and  the  fuel,  starting  air,  spray  air,  and  water  piping  at- 
tached to  it. 


Figure  6.     Busch-Sulzer  Cylinder.    Showing   Two-Cycle  Scavenging 
Sulzer  System. 

Space  requirements  in  the  engine  room  is  a  more  important  consid- 
eration. For  the  same  power  and  speed,  whatever  practical  number  of 
cylinders  is  selected,  the  two-cycle  engine  for  similar  service  occupies 
less  space  than  the  four-cycle. 

Engines  may  be  built  of  almost  any  weight  per  unit  of  power.  Slow- 
speed  stationery  Diesel  engines  weigh  as  much  as  350  to  400  pounds  per 
B.  H.  P.,  while  high-speed  Diesel  engines  for  propelling  submarine  boats 
weigh  as  little  as  45  to  50  pounds  per  B.  1H.  P.  In  comparing  the  weights 
of  engines,  therefore,  the  first  consideration  must  be  their  respective 
speeds  and  purposes. 


244  DESCRIPTION  OF  DIESEL  ENGINES 

Engines  of  the  same  speed  and  power,  and  for  the  same  service,  vary 
within  wide  limits  in  weights,  according  to  their  design,  but  if  of  sub- 
stantially equal  ruggedness,  the  two-cycle  Diesel  weighs  from  20  to  30 
per  cent  less  than  the  four-cycle.  Any  reduction  in  weight  which  is  ob- 
tained by  a  reduction  of  rigidity  and  safety,  should  be  scrupulously 
avoided. 

(Scavenging  comprises  two  functions:  the  clearing  of  the  previous 
combustion,  or  burnt  gases,  by  means  of  a  current  of  air,  and  the  sup- 
ply of  the  air  charges  necessary  for  the  next  combustion.  The  Sulzer 
scavenging  system  used  on  the  Busch-Sulzer  Diesel  comprises  a  safe  and 
simple  method  of  thorough  scavenging.  It  utilizes  port-scavenging,  but 
employs  two  tiers,  instead  of  only  one  tier  of  ports.  The  piston  uncovers 
the  upper  tier  of  scavenging  of  ports  before,  and  the  lower  tier  after,  it 
uncovers  the  exhaust  ports,  but  the  communication  between  the  interior  of 
the  cylinder  and  the  scavenging-air  supply  or  receiver,  through  the  upper 
ports,  is  controlled  by  a  timed  and  mechanically  operated  valve,  which 
remains  closed  until  the  exhaust  ports  have  been  uncovered  long  enough 
to  reduce  the  pressure  of  the  gases  in  the  cylinder  to  nearly  atmospheric; 
after  which  this  valve  is  opened,  while  the  piston  uncovers  the  lower 
scavenging  ports;  a  rapid  and  thorough  purging  is  then  effected  with  com- 
plete safety  against  a  blowback  into  the  scavenging  receiver. 

Upon  its  return  stroke,  the  piston  first  covers  the  lower  scavenging 
ports,  and  then  the  exhaust  ports;  the  upper  scavenging  ports  and  their 
valve  remain  open,  enabling  the  scavenging  air  to  fill  the  cylinder  at  full 
scavenging  pressure  before  the  communication  is  shut  off  by  the  piston. 
Obviously  a  blow-back  of  exhaust  gases  into  the  cylinder  cannot  occur; 
furthermore,  the  double  tier  arrangement  and  proper  form  of  scavenging 
ports  insure  a  clearing  out  of  such  thoroughness  that  substantially  no 
burnt  gases  remain  in  the  cylinder — analyses  have  shown  that  this 
residue  does  not  exceed  3  per  cent.  The  weight  of  air  compressed  is  thus 
substantially  100  per  cent  of  the  weight  of  a  cylinder  full  at  atmospheric 
pressure,  and  it  is  possible  to  perfectly  consume  the  full  quantity  of  fuel. 

The  effectively  directed  streams  of  scavenging  air  cool  the  cylinder 
more  evenly  than  is  possible  with  ordinary  port-scavenging.  The  com- 
plete cycle  of  the  Sulzer  scavenging  and  charging  system  is  shown  in 
fiigure  7  (a)  to  (h). 

In  general,  the  Busch-Sulzer  two-cycle  marine  Diesel  may  be  des- 
cribed as  follows:  The  engines  are  vertical,  four  or  six  cylinders,  single- 
acting,  crosshead  type,  two-cycle;  giving  one  power  stroke  per  cylinder  per 
revolution  of  the  crankshaft.  The  injection  air  compressor  is  directly 
driven  from  a  crank  on  an  extension  of  the  main  crankshaft.  The  scav- 
enging air  pump  is  directly  driven  in  the  same  manner  as  the  compressor 
except  for  the  larger  twin  units  for  which  turbo-Mowers  are  employed 
to  supply  the  scavenging  air.  The  engines  are  designed  for  heavy  duty 
service  with  all  parts  readily  accessible  for  inspection  and  adjustment. 
Workmanship  is  of  the  highest  class,  jigs  and  fixtures  are  used  in  machin- 
ing processes,  so  that  all  parts  of  the  same  kind  and  size  are  inter- 
changeable. 


DESCRIPTION  OF  DIESEL  ENGINES 


245 


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246  DESCRIPTION  OF  DIESEL  ENGINES 

Iron  casting  are  of  grades  which  experience  has  shown  to  be  especially 
adapted  to  withstand  stresses,  heat,  or  wear  as  demanded  by  the  service 
for  which  each  is  intended.  Abrupt  changes  of  section  and  excessive  ac- 
cumulation of  mass  are  avoided.  The  steel  castings  possess  carefully  de- 
termined properties,  and  are  thoroughly  annealed.  Forgings  are  of  grades 
of  steel  which  comply  with  rigid  specifications. 

Bed  Plate  and  Crank  Case:  The  bed  plat©  is  built  up  of  sections,  of 
strong,  medium-soft  cast  iron.  It  is  provided  with  ample  flanges,  planed 
on  their  undersides,  for  rigid  bolting  to  the  foundation.  It  comprises 
an  oil-collecting  trough  with  bridges  between  each  two  cylinders,  which 
bridges  contain  bored  seats  for  the  main  bearing  shells. 

The  crank  case  is  oil  and  gas  tight,  and  of  the  enclosed  type;  it  is 
built  up  of  sections,  of  the  same  quality  of  cast  iron  as  the  bedplate.  It  is 
rigidly  bolted  to  the  top  of  the  bed  plate  and  provided  with  large  covers, 
readily  removable  for  inspection  and  adjustments,  making  all  parts  in- 
side the  crank  case  easily  accessible.  The  covers  carry  hinged  inspec- 
tion doors,  for  convenience  in  making  inspections,  while  the  engine  is  in 
operation,  without  throwing  oil. 

The  crank  case  carries  the  crosshead  guides,  and  the  cylinder  jackets 
are  bolted  directly  to  its  top. 

Working  Cylinders:  Each  working  cylinder  consists  of  two  main 
pieces — an  outer  jacket  which  carries  all  axial  stresses;  and  a  liner, 
\vhich  constitutes  the  running  barrel. 

The  lower  end  of  the  outer  jacket  is  bolted  directly  to  the  crankcase; 
the  upper  end  is  provided  with  studs  to  hold  the  cylinder  head.  Openings 
at  the  front  and  back  provide  for  the  scavenging  air  and  exhaust  con 
nections. 

The  jacket  is  of  the  same  quality  of  cast  iron  as  the  bed  plate  and 
crank  case,  and  is  furnished  with  hand  holes  for  the  inspection  and  clean- 
ing of  the  cooling  water  spaces. 

The  liner  is  of  special  hard,  close-grained  cast  iron,  particularly 
adapted  to  its  service.  It  is  provided  with  slots  or  ports  in  its  wall,  for 
the  admission  of  the  scavenging  air  and  the  discharge  of  the  exhaust 
gases.  The  upper  end  seats  on  a  shoulder  in  the  jacket,  making  an  ab- 
solutely water-tight  joint. 

The  center  belt,  or  the  portion  of  the  liner  at  the  scavenging  and 
exhaust  ports,  is  turned  to  fit  a  bored  seat  in  the  jacket,  and  is  provided 
with  packings  to  make  water  and  gas-tight  joints  above  and  below  ports. 

The  lower  end  of  the  liner  carries  the  oil-wiper  rings,  and  passes 
through  the  bottom  flange  of  the  cylinder  jacket,  where  a  stuffing  box 
is  provided  to  make  a  water-tight  joint  between  the  outside  of  the  liner 
and  the  lower  end  of  the  cylinder  jacket. 

The  entire  construction  allows  free  expansion  of  both  parts.  The 
space  between  the  liner  and  the  jacket  constitutes  the  water  jacket. 

The  upper  face  of  the  liner  is  provided  with  a  groove,  into  which  the 
tongue  of  the  cylinder  head  registers,  making  an  absolute  ^as-tight  joint. 


DESCRIPTION  OP  DIESEL  ENGINES  247 

Cylinder  Heads:  The  cylinder  heads  are  of  special  medium  hard 
cast  iron.  They  are  of  simple,  symmetrical  design,  the  head  containing 
only  central  opening  of  relatively  small  diameter,  to  receive  the  combined 
fuel  valve  and  starting  valve  cage,  thus  insuring  freedom  from  casting 
and  heat  stresses,  and  greatest  resistance  to  all  working  stresses.  The 
heads  do  not  contain  any  scavenging  or  exhaust  valves.  Ample  and  un- 
obstructed water-jacketing  is  provided.  In  this  design  of  head  the  ring 
of  relatively  cool  metal  surrounding  the  hot  central  portion — common  to 
all  other  designs — has  been  eliminated. 

The  cylinder  head  is  rigidly  bolted  to  the  top  of  the  cylinder  jacket, 
with  a  registered  fit  on  the  cylinder  liner.  The  underside,  or  combustion 
space  side,  of  the  head  is  concave,  forming,  in  conjunction  with  the  con- 
cave top  face  of  the  piston,  a  symmetrical  combustion  space  of  ideal 
shape. 

The  cylinder  heads  are  provided  with  hand  holes  for  the  inspection 
and  cleaning  of  the  cooling  water  spaces. 

Valves  and  Valve  Gear:  Scavenging  air  enters  and  the  exhaust  gases 
are  discharged  through  the  ports  in  the  cylinder  wall,  which  ports  are 
opened  and  closed  to  the  cylinder  by  the  piston  uncovering  the  ports  on 
the  down-stroke  and  covering  them  on  the  up-stroke,  near  the  lower  end 
of  its  stroke. 

On  the  scavenging  side  of  the  cylinder  there  are  two  tiers  of  ports. 
The  upper  tier  is  controlled  by  a  timed  rotary  scavenging  valve,  driven 
from  the  vertical  shaft  of  the  engine;  the  lower  tier  has  a  free  opening 
into  the  scavenging  air  receiver.  This  patented  arrangement  insures 
perfect  scavenging  and  the  complete  charging  of  the  cylinder  with  pure 
air,  while  the  scavenging  valve  is  out  of  range  of  the  hot  gases. 

The  fuel  valve  and  starting  valve  are  carried  in  a  common  water- 
cooled  cage,  located  in  the  central  opening  in  the  cylinder  head,  so  that 
the  valves  work  in  a  vertical  position. 

The  camshaft,  carrying  the  cams  for  operating  the  valves,  extend  in 
front  and  along  the  tops  of  the  cylinders,  in  an  entirely  enclosed  casing, 
and  is  driven  from  the  crankshaft,  at  engine  speed,  through  a  pair  of 
helical  gears  at  the  lower  end  of  the  vertical  shaft  and  a  pair  of 
bevel  gears  at  the  upper  end.  This  drive  is  located  at  the  flywheel  end 
of  the  engine,  and  taken  off  the  main  crankshaft  on  the  flywheel  side  of 
the  first  journal,  where  it  is  least  subjected  to  torsional  irregularities 
which  might  effect  the  operation  of  the  gears  and  the  governing  of  the 
engine. 

The  toothed  gears  work  in  oil,  and  are  enclosed  in  oil-tight  housings. 

Reversing  Gear:  The  engines  are  provided  with  double  sets  of  start- 
ing and  fuel  cams,  and  the  necessary  levers  and  gear  to  permit  the  direc- 
tion of  rotation  of  their  crankshafts  to  be  promptly  reversed.  The  gear 
is  air-operated  and  suitable  interlocking  devices  are  provided  to  safe- 
guard the  engine  against  being  started  or  reversed  with  the  gear  in  im- 
proper position. 


248 


DESCRIPTION  OP  DIESEL  ENGINES 


Safety  Overspeed  Governor:  The  engines  are  fitted  with  suitable 
overspeed  governors,  which  prevent  racing,  by  cutting  off  the  supply  of 
fuel  to  the  cylinders  when  the  speed  exceeeds  a  pre-determined  limit,  for 
which  the  governors  may  be  adjusted.  The  supply  of  fuel  is  automatically 
re-established  as  soon  as  the  speed  of  the  engine  falls  to  normal. 

Fuel  Pump:  The  fuel  pump  is  of  the  multiple  plunger  type  (one 
plunger  for  each  cylinder),  operated  from  the  vertical  shaft.  The  func- 
tion of  this  pump  is  to  deliver  to  each  cylinder  the  quantity  of  fuel  neces- 
sary to  maintain  the  desired  speed  and  develop  the  required  power.  The 
amount  of  fuel  delivered  is  determined  by  the  seating  point  of  the  fuel 
pump  suction  valves,  which  point  is  controlled  automatically  by  the 
governor  of  the  stationary  engine,  and  by  hand  from  the  control  levers 
of  the  marine  engine. 

The  fuel  piping  is  provided  with  visible  overflow  valves  to  free  the 
lines  from  any  accumulated  air,  which  would  interfere  with  prompt 
starting. 


Figure  8.    Busch-Sulzer  Piston  Cooling. 

Pistons:  The  piston  proper  is  short,  merely  long  enough  to  accom- 
modate the  piston  rings,  as  all  guiding)  is  performed  by  the  cross-heads. 
It  is  provided  with  a  water  jacket  immediately  under  its  upper  face.  The 
piston  rod  is  attached  to  the  lower  flange  of  this  piston,  by  means  of 
studs.  The  piston  is  of  special,  hard,  close  grained  cast  iron,  best  suited 
to  resist  the  heat  and  working  conditions  to  which  it  is  subjected.  The 
piston  rings  are  single-piece  rings,  of  a  grade  of  cast  iron  which  will 
retain  its  springing  qualities  until  it  is  worn  out. 


DESCRIPTION  OF  DIESEL  ENGINES  249 

The  piston  is  water-cooled  by  a  patented  arrangement.  The  water  is 
injected  into  the  cooling  chamber  in  the  piston  head,  and  conducted  away 
from  same,  by  a  system  of  telescopic  tubes  arranged  on  a  principle  which 
avoids  swing  joints,  while  preventing  oil  and  water  leakage. 

Immediately  below  the  piston  is  fitted  a  skirt,  the  sole  function  of 
which  is  to  cover  the  scavenging  and  exhaust  ports  in  the  cylinder  wall. 
The  skirt  is  of  hard,  close-grained  cast  iron. 

Piston  Rods:  The  piston  rod  is  of  forged  open-hearth  steel.  The 
upper  end  is  provided  with  an  integral  flange,  for  attachment  to  the 
piston;  the  lower  end  is  forked,  to  connect  to  the  crosshead  pin  . 

Crosshead  Pins:  The  crosshead  pin  is  a  high-carbon,  open-hearth 
steel  forging.  The  central  'part  of  the  pin  forms  the  bearing  for  the  con- 
necting rod.  To  each  side  of  this  bearing  is  bolted  the  forked  end  of  the 
piston  rod.  The  ends  of  the  pins  carry  the  crossheads.  Shims  are  pro- 
vided between  the  crosshead  pin  and  the  end  of  the  piston  rod,  to  permit 
the  adjustment  of  the  compression  in  the  cylinder. 

Crossheads:  The  crossheads  are  of  cast  iron,  with  babbitted  bearing 
faces.  They  are  of  the  double,  central  guide  type.  No  loose  or  adjust- 
able pieces  are  attached  to  them;  adjustment  being  provided  by  shims 
under  the  stationary  guides,  bolted  to  the  crank  case. 

Connecting  Rods:  The  connecting  rods  are  of  forged  open-hearth 
steel,  with  marine  type  crosshead  and  crank  ends.  The  end  bolts  are  of 
special  soft  steel,  designed  to  avoid  localized  stresses  and  to  resist  crys- 
tallization. 

The  crosshead  pin  boxes  and  crank  pin  boxes  are  of  cast  steel,  bab- 
bitt lined,  adjustable  by  means  of  shims.  Dovetailed  grooves  are  machined 
for  anchoring  the  babbitt  in  these  boxes,  and  tinned  before  pouring  the 
babbitt,  thus  making  an  absolute  bond  between  babbitt  and  box. 

Crankshaft:  The  crankshaft  is  in  three  sections,  each  section  made 
from  a  single  open-hearth  heat-treated  steel  forging.  Each  main  section 
carries  two  cranks  for  a  four-cylinder  engine,  or  three  cranks  for  a  six- 
cylinder  engine,  and  is  provided  with  integrally  forged  flanges  at  both 
ends.  The  two  main  sections  are  interchangeable  with  one  another.  The 
third  section  carries  the  cranks  for  driving  the  scavenging  pump  and  air 
compressor,  and  is  provided  with  an  integral  flange  to  bolt  to  the  main 
section.  All  corners  are  carefully  filleted.  The  shaft  is  bored  to  permit 
examination  of  the  material,  and  to  afford  passage  for  the  lubricating  oil. 

The  shaft  is  made  to  specifications  especially  covering  the  class  of 
steel  and  manufacture  required  for  this  service.  Material,  dimensions, 
and  construction  of  the  crankshaft  are  approved  by  Lloyd's  Register  of 
Shipping. 

Main  B'earings:  The  main  bearings  are  cast  iron  cylindrical  shells, 
in  halves,  lined  with  babbitt  anchored  in  machined  and  tinne^  dovetail 
grooves.  The  bottom  half-shells  are  fitted  and  scraped  into  the  board 
seats  in  the  bed  plate;  the  top  half-shells  are  fitted  into  bored  seats  in 
the  bearing  caps.  Between  the  two  halves  shims  are  provided  for  ad- 


250  DESCRIPTION  OF  DIESE,L  ENGINES 

justment.     The  shells  are  securely  held  in  place  by  the  main  bearing 
caps,  which  are  fitted  and  rigidly  bolted  to  the  bed  plates. 

The  seats  for  the  bottom  half-shells  are  absolutely  lined  up  before 
the  shells  are  put  in.  After  the  shells  are  placed  in  the  seats,  they  are 
scraped  to  the  crankshaft,  to  exact  alignment. 

Flywheel  and  Extension  Shaft:  The  flywheel  is  carried  on  an  exten- 
sion shaft,  connected  to  the  crankshaft  by  means  of  a  solid-forged  coup- 
ling flange.  The  flywheel  rim  is  provided  with  teeth  for  barring  over  the 
engine.  The  extension  shaft  is  arranged  to  couple  the  thrust. 

Scavenging  Pump  and  Receivers:  The  scavenging  pump  for  provid- 
ing low-pressure  scavenging  and  charging  air  for  the  working  cylinders, 
is  mounted  vertically  on  the  crankcase,  at  the  opposite  end  from  the  fly- 
wheel, next  to  the  forward  working  cylinder  and  in  line  with  same.  It  is 
directly  driven  from  the  crank  on  the  extension  to  the  main  crankshaft, 
and  is  provided  with  crosshead  and  guides  similar  to  those  of  the  work- 
ing cylinders. 

The  suction  and  discharge  valves  are  of  a  patented,  simple,  auto- 
matic "shutter"  type  mounted  in  cages.  These  valves  are  identical  in 
size  and  design,  and  are  interchangeable.  No  springs  or  plates  subject 
to  flexure  are  used. 

The  intake  side  of  the  pump  is  provided  with  a  valve  chest,  arranged 
so  that  the  scavenging  air  may,  if  desired,  be  brought  from  outside  of 
the  engine  room.  The  discharge  side  is  provided  with  a  valve  chest, 
with  connections  to  the  scavenging-air  receiver,  which,  in  turn,  provides 
the  connection  to  the  working  cylinders. 

The  scavenging^air  receiver  is  of  cast  iron.  It  extends  along  the 
front  of  the  engine  and  is  bolted  to  faces  on  the  working  cylinder  jackets. 
It  provides  a  firm  support  for  the  valve  gears,  cam-shaft  bearings,  and 
casings.  A  pressure  relief  is  'fitted  to  the  receiver. 

The  suction  and  discharge  valve  chests  are  fitted  with  large  covers, 
for  access  to  the  valves.  The  scavenging-air  receiver  is  provided  with 
covers  for  access  to  the  rotary  scavenging  valves. 

Air  Compressor:  The  air  compressor,  for  providing  compressed  air 
for  fuel  injection  and  starting,  is  mounted  vertically  on  the  crankcase, 
at  the  forward  end  of  the  engine,  in  line  with  working  cylinders.  It  is 
directly  driven  from  a  crank  on  the  extension  to  the  main  crankshaft,, 
The  compressor  is  three-stage,  water- jacketed,  and  provided  with  adequate 
intercoolers  and  aftercoolers,  to  keep  the  air  at  a  low  temperature.  The 
piston  is  of  standard  differential  trunk  type,  with  patented  removable 
piston  pin  housing.  The  compressor  valves  are  without  springs  and  are 
easily  removable  for  quick  inspection  and  cleaning.  The  second  and  third 
stage  valves  and  seats  are  of  a  specially  heat-treated  alloy  steel,  found  by 
experiment  the  best  to  resist  wear  and  breakage. 


DESCRIPTION  OF  DIESEL  ENGINES 


251 


Each  stage  of  the  compressor  is  protected 
against  excessive  pressure  by  a  safety  valve  of 
special  design  and  ample  capacity.  A  regulating 
device  is  provided,  to  adjust  the  injection  air  pres- 
sure to  suit  the  operating  conditions. 

The  air  coolers  are  constructed  to  afford 
ready  access  for  inspection  and  cleaning,  and  are 
provided  with  sufficient  oil  and  water  separators 
and  drains. 

Air  Starting  System:  The  engine  is  started 
by  means  of  compressed  air,  furnished  by  the 
injection  air  compressor.  The  engines  are  pro- 
vided with  air  starting  on  all  cylinders,  and  one- 
half  of  the  cylinders  are  started,  followed  by  the 
other  half. 

Air  Tank  and  Piping:  The  injection  and 
starting  air  piping  is  extra  heavy,  annealed  and 
tested  seamless  drawn  steel  tubing,  provided  with 
special  high-pressure  fittings. 

Adequate  injection  air  and  starting  air  storage 
tanks  are  furnished.  Each  tank  is  provided  with 
a  special  shut-off  valve  and  proper  drainage.  The 
starting  air  tanks  are  so  connected  up  that  they 
can  be  charged  from  the  compressor  without  in 
any  way  interfering  with  the  operation  of  the  en- 
gine. 

The  air  tanks  are  of  seamless  drawn  steel; 
manufactured,  tested,  inspected,  and  stamped  in 
accordance  with  L.  C.  C.  Shipping  Container 
Specifications  No.  3-A,  and  comply  with  the  re- 
quirements of  Lloyd's  Register  of  .Shipping.  Each 
tank  is  provided  with  a  fusible  safety  plug,  to  re- 
lieve the  pressure  in  case  of  fire. 

Water  Cooled  System:  The  air  compressor,  cylinder  heads,  cylin- 
ders, pistons,  fuel  and  starting  valve  cages,  exhaust  manifolds,  and  the 
oil-coolers,  are  provided  with  arrangements  for  efficient  water  cooling. 
There  are  no  hidden  water  overflow  and  by-pass  connections. 

All  cooling  water  is  discharged  into  accessible  open  funnels,  and 
individual  outlet  pipes  are  provided  for  each  cylinder,  so  that  the  tem- 
perature of  the  discharges  from  the  various  engine  parts  may  readily 
be  observed. 

Lubrication:  The  general  lubrication  is  a  pressure  system  providing 
all  main  bearings,  crank  pins  and  cross-head  pin  bearings,  cross-heads, 
vertical  shaft  thrust  bearing,  and  lower  helical  gears  with  a  continuous 
supply  of  cool,  clean  oil  under  pressure. 

The  oil,  after  passing  thru  the  bearings,  is  collected  in  the  bed 
plate,  and  flows  thru  a  twin  filter  to  a  displacement  type  pump,  wnioh 


Fig.  10  —  Cross 

Section  Through 

Compressor* 


252 


DESCRIPTION  OP  DIESEL  ENGINES 


forces  it  thru  a  cooler,  from  which  it  is  again  delivered  to  the  bearings, 
at  a  pressure  of  10  to  20  pounds.  A.  safety  valve  is  provided  on  the  oil 
pressure  pipe;  also  bypass  connections,  for  the  regulation  of  the  pres- 
sure. 

All  camshaft  bearings  are  provided  with  oiling  rings.  The  cylinders, 
including  the  cylinders  of  each  stage  of  the  compressor,  are  oiled  by  a 
multi-feed  pressure  type  oil  pump.  Oil  cups  are  provided,  where  neces- 
sary.; 

Barring  Gear:  A  suitable  barring  gear  is  provided  for  turning  the 
engine  over;  although  the  four-cylinder  engines  of  this  type  do  not  re- 
quire barring  into  a  starting  position,  as  they  readily  start  at  any  crank 
position. 

Platform,  Stairs,  Railing:  The  necessary  platforms,  stairs,  and  rail- 
ings to  give  access  to  all  parts  requiring  attendance  for  operation,  are 
provided. 

Fuel  Oil  Service  Tank  and  Filters:  A  suitable  and  adequate  fuel  ser- 
vice tank  is  furnished,  to  contain  a  supply  of  fuel  for  the  engine. 

A  twin  fuel  filter  is  provided,  to  remove  foreign  matter  from  the 
fuel  before  it  reaches  the  engine. 

Accessories:  Pressure  gauges  are  provided  for  the  air  compressor, 
air  storage  tanks,  lubricating  oil,  and  piston  cooling  water. 

Thermometers  are  provided  in  the  lubricating  oil  lines,  at  points 
before  and  after  the  cooler. 


Figure  IG. 
Curve  Showing  Fuel  Consumption — 1,250  B.H.P. — Sulzer  Two-Cycle 

Under  test  conditions,  and  at  equal  loads,  tlie  four-cycle  engine  may  con- 
sume 6  to  8%  less  fuel  than  the  two-cycle.  In  actual  practice  this  advan- 
tage is,  however,  apparently  smaller,  due  to  the  fact  that  the  large  two-cycle 
engine  may  be  more  safely  operated  continuously  at  full  load  and  best  ef- 
ficiency than  may  the  large  four-cycle,  and  also  due  to  the  fact  that  more 
complete  combustion  is  obtained  in  the  two-cycle  at  fractional  loads,  due 
to  the  higher  temperature  in  the  cylinder. 


DESCRIPTION  OF  DIESEL  ENGINES 


253 


THE  DOW  DIESEL  ENGINE 

The  Dow  Full  Diesel  Type  Marine  Oil  Engine  is  of  the  vertical  multi- 
cylinder  design,  built  in  sizes  from  320  B.  H.  F.  to  1000  B.  H.  P.  It 
follows  the  four-cycle  principle.  The  engine  is  direct-reversible  and  em- 
bodies features  of  improved  methods  in  Diesel  operation. 


Figure   (a)     Full  View  of  Dow  Direct-Reversible  Marine  Diesel  Engine. 


As  every  respective  engine  has  a  special  feature  characteristic  in 
Diesel  manufacture,  or  a  design  by  which  it  in  many  cases  tends  to  be 
classified  in  a  type  of  its  own,  still  following  the  laws  as  laid  down  in 
Diesel  prime  movers,  so  has  the  Dow  engine  distinctive  departures  from 
the  usual  types  of  Diesels. 

In  particular,  the  designers  have  laid  stress  on  the  importance  of 
equal  distribution  of  fuel.  As  will  be  noticed  in  Figure  (a),  each  set  of 
three  cylinders  are  supplied  in  common  with  one  fuel  pump  instead  of 
individual  pumps  for  each  cylinder,  which  permits  of  an  accurate  and 
even  distribution  of  oil  for  each  cylinder. 


254 


DESCRIPTION  OF  DIESEL  ENGINES 


The  output  of  the  fuel  pump  is  controlled  by  the  usual  system  of 
governor  control,  the  governor  being  of  the  centrifugal  type.  In  simi- 
larity to  the  general  principle  prevailing  on  Diesels,  the  governor,  which 
operates  directly  on  the  fuel  pump,  regulates  the  supply  of  fuel  oil  to 
the  injection  valves  in  proportion  to  the  load  on  the  engine,  at  all  times 
maintaining  the  pre-determined  speed  in  revolutions  per  minute  of  the 
propeller. 

fi 


The  governor  is  entirely  enclosed  and  mounted  on  the  vertical  driv- 
ing shaft  directly  geared  to  the  engine  crankshaft.  It  is  provided  with 
hand-regulating  attachment  so  that  the  speed  of  the  engine  may  be 
varied  by  hand  while  the  engine  is  in  operation. 

This  novel  arrangement  adds  greatly  to  the  accurate  performance  of 
the  engine,  in  particular  on  long  voyages  where  heavy  seas  are  experi- 


DESCRIPTION  OF  D1ESE.L  ENGINES 


255 


enced  and  racing  of  engine  are  the  results,  very  often  causing  complica- 
tions with  consequential  injury  to  the  engine. 

The  cylinder  heads  are  of  box  section  and  water-jacketed.  Air,  fuel, 
exhaust  and  starting  valves  are  all  contained  in  the  cylinder  head,  their 
operating  levers  being  securely  supported  by  bearings  mounted  on  and 
bolted  to  the  heads. 


Special  care  has  been  given  to  the  construction  of  all  valves  and 
valve  seats,  which  are  of  the  removable  type,  allowing  them  to  be  readily 
withdrawn  from  the  cylinder  head  for  inspection  and  re-grinding  when 
required.  All  the  valves  are  opened  by  the  action  of  steel  levers  rolling 
on  hardened  cams.  The  cams  are  accurately  set  and  keyed  in  place,  in- 
suring positive  action.  The  valve  gear  is  of  the  cam  type  throughout,  the 
cam-shaft  being  driven  by  machine-cut  spiral  gears.  All  levers  for  oper- 


256  DESCRIPTION  OF  DIESEL  ENGINES 

ating  cams  are  provided  with  case-hardened  rollers  and  pins.  Special 
care  is  taken  in  the  design  of  the  exhaust  valve  lever,  so  that  the  exhaust 
valve  and  seat  may  be  removed  without  disturbing  the  valve  gear. 

Reversing  Mechanism:  Briefly  described,  the  reversing  of  the  engine 
consists  in  the  changing  over  from  one  set  of  cams  to  another;  the  work 
being  performed  by  an  air-driven  ram.  The  operator  simply  moves  a 
small  hand  lever  to  accomplish  the  reversal  position.  This  -operation  is 
immediately  followed  by  the  movement  of  the  main  control  lever  to  start- 
ing air  position,  where  it  is  allowed  to  remain  during  one  or  two  im- 
pulses. At  the  completion  of  this  operation  this  same  lever  is  moved  to 
running  'position.  The  whole  above-described  maneuver  is  accomplished 
in  five  seconds  from  full  speed  ahead  to  full  speed  astern  position. 

The  air-driven  cams  referred  to  above  automatically  lifts  the  cam 
rollers  clear  of  all  cams,  then  slides  the  cam  shaft  to  the  desired  posi- 
tion and  returns  the  cam  rollers  to  the  cams.  The  control  lever  is 
securely  interlocked  with  shifting  mechanism,  preventing  any  false  move 
on  the  part  of  the  operator. 

The  thrust  block  is  of  the  standard  marine  horseshoe  type,  is  equip- 
ped for  water  cooling.  It  is  -securely  bolted  and  doweled  to  the  main 
engine  bed-plate,  insuring  perfect  alignment. 

In  illustration  (c)  an  ideal  engine  is  shown  for  tugboat  service  or 
yachts,  or  such  smaller  types  of  vessels  employed  on  coast-wise  trade. 
As  will  be  seen,  this  engine  is  equipped  with  reverse-gear.  This  type  of 
engine  stands  up  to  heavy  duty  such  engines  are  very  often  subjected  to. 

The  Dow  Diesel  Engine  follows  the  "A"  frame  construction.  The 
bed-plate,  which  extends  the  full  width  and  length)  of  the  engine,  is  of 
box  girder  section  throughout,  reinforced  with  transverse  and  longitud- 
inal ribs.  The.  bed-plate  carries  the  main  bearing  journals  and  seating 
for  the  "A"  frame. 

Forced  lubrication  is  provided  for  all  cylinders  and  piston  pins,  while 
all  main  journals  and  outboard  bearings. are  furnished  with  ring  oilers. 
All  crank  pins  are  lubricated  by  gravity  and  centrifugal  oilers.  (Note. — 
For  Compressor,  see  Section  on  Compressors.) 


DESCRIPTION  OF  DIESEL  ENGINES 


257 


THE  FULTON   DIESEL  ENGINE 

The  Fulton  Iron  Works  Company,  in  developing  the  Fulton  Diesel 
Engine,  as  patterned  and  designed  by  Franco  Tosi,  one  of  Europe's  fore- 
most engineers  of  Diesel  Engines,  has  produced  one  of  the  most  effi- 
cient and  dependable  prime  movers  obtainable. 


The  Fulton  Diesel  Oil  Engines  not  only  possess  all  the  advantages 
of  the  typical  European  oil  engine,  but  has  been  developed  by  many  re- 
finements and  improvements  for  American  service  by  the  engineers  of 
the  Fulton  Iron  Works  Company.  With  following  explanation  it  will  be 


258 


DESCRIPTION  OF  DIESEL  ENGINES 


seen  that  the  improvements  embodied  in  this  engine  brings  it  on  an 
equal  standing  with  modern  types,  in  particular  as  an  engine  adapted 
for  stationary  service. 

As  will  be  seen  in  other  pages  of  this  book,  the  Tosi  Diesel  engine 
has  been  brought  to  the  highest  stage  of  perfection  and  is  used  today  on 
exceedingly  large  ships  in  merchant  service. 

Like  the  Junkers  type  and  many  German  patents,  it  has  been  a  pro- 
duct created  by  years  of  experiments  and  brought  up  to  the  highest  stage 
of  perfection.  It  is  an  oil  engine  operating  on  fuels  of  low  gravity  and 
in  consequence  its  maintenance  is  very  inexpensive. 

The  most  distinctive  features  of  this  engine  are  found  in  the  strength 
of  their  heavy  "A"  frame  construction,  the  accessibility  of  all  bearings, 
and  the  fact  that  the  cylinder  liners  can  be  readily  removed  without  dis- 
mantling the  engine. 

The  cam  shaft  is  on  a  level  with  the  cylinder  head,  and  the  arrange- 
ment of  all  parts  is  so  simple  that  adjustments  can  be  made  easily  and 
economically,  even  while  the  engine  is  in  operation. 


Diagram  Showing  Full  Illustration  of  Engine  with  Compressor,  Pumps, 
Lubrication  System,  Etc. 


As  the  Fulton  Oil  Engine  is  of  the  four-cycle,  vertical,  "A"  frame 
type,  it  is  not  subjected  to  the  strains  that  are  usually  found  in  internal 
combustion  engines  of  the  horizonal  types.  This  design  practically  elim- 
inates vibration  which  is  an  additional  factor  for  long  life  in  the  engine. 


DESCRIPTION  OP  DIESEL  ENGINES 


259 


This  engine  is  equipped  with  a  three-stage  compressor.  It  is  directly 
connected  to  the  crankshaft  end  and  provides  the  large  storage  tank  with 
highly  compressed  air  for  both  starting  and  for  the  purpose  of  fuel  in- 
jection. 

The  Fulton  fuel  pump  is  of  the  variable  plunger  stroke  type,  with 
positive  control  from  the  governor.  The  needle  valves  are  under  control 
from  operator's  stand.  The  exceptional  strong  construction  of  the  force- 
feed  pump  is  of  similar  design  as  will  be  seen  in  the  usual  types  of 
Diesel  Engine.  The  necessity  in  providing  proper  lubrication  method  is 
taken  care  of  in  this  engine  by  sight-feed  gravity  oilers,  which  supply  all 
bearings  with  copious  quantities  of  oil. 


Diagram  of  Fulton  Diesel  Engine,  Looking  from  Compressor  In. 

View  of  Engine 


End 


By  means  of  the  Fulton  patent  starting  mechanism  the  air  is  de- 
livered to  the  starting  cylinders  and  at  the  same  time  positively  locks 
all  fuel  oil  from  the  cylinders. 

The  Fulton  design  is,  such  as  allows  of  quick,  easy  and  inexpensive 
replacement  of  all  wearing  parts  by  means  of  bushing,  brasses,  etc. 


260 


DESCRIPTION  OP  DIESEL  ENGINES 


A  very  advantageous  feature  in  adding  to  the  economy  of  the  engine 
is  the  system  of  oil  filtering.  All  the  oil  that  is  introduced  into  the 
engine  is  handled  by  a  three-plunger  pump  at  the  compressor  end  of  the 
crankshaft.  The  center  plunger  pumps  fuel  oil  from  the  storage  tank  to 
a  gravity  tank.  The  outside  plungers  pump  clean  lubricating  oil  to  a 
gravity  tank  and  the  dirty  oil  from  the  pump  to  the  filter.  All  the  lubri- 
cating oil  that  flows  into  the  pump  is  run  into  a  settling  tank,  then 
through  an  oil  filter  where  the  oil  is  filtered  through  bone  black.  This 
permits  the  lubricating  oil  to  be  reclaimed  in  a  large  measure  and  none 
but  clean  oil  to  return  to  the  engine.  By  the  use  of  bone  black  for 
filtering,  the  oil  is  completely  revivified.  By  the  above  means  of  lubri- 
cation great  economy  has  been  obtained.  By  actual  operating  figures 
obtained  from  a  500  B.H.P.  3-cylinder  engine,  driving  a  350-kw.  alter- 
nator, it  is  found  that: 

1  gallon  cylinder  oil  serves 8,283.3  kw.  hr. 

1  gallon  bearing  oil  serves 7,455     kw.hr. 

1  gallon  compressor  oil  serves 74,550     kw.  hr. 


Diagram  of  Fulton  Diesel  Engine.     Good  View 

The  governing  of  the  Fulton,  Diesel  oil  engine  is  accomplished  by  a 
Jahn's  type  governor,  driven  from  the  vertical  shaft.  This  governor  acts 
directly  on  the  fuel  pump  of  the  engine  so  that  any  change  in  the  load 
is  almost  instantly  compensated  by  a  quick  response  from  the  engine. 
There  is  no  lagging  or  "hunting." 

The  old  method  of  driving  the  governor  by  the  vertical  shaft  was  to 
place  the  governor  directly  on  that  shaft.  This  necessitated  using  a 


DESCRIPTION  OF  DIESEL  ENGINES  261 

large  governor,  running  the  same  speed  as  the  shaft.  It  was  found  that 
every  vibration  imparted  to  the  cam  shaft  by  the  action  of  the  cam  was 
transmitted  directly  to  the  vertical  shaft  and  hence  to  the  governor,  caus- 
ing undue  wear.  To  eliminate  this  undue  wear  on  the  Fulton  engine,  the 
governor  was  offset  from  the  vertical  shaft,  and  driven  by  flexible  gears. 
It  was  also  found  that  by  this;  method  a  smaller  governor  could  be  used 
and  run  at  higher  speed,  thus  giving  a  better  regulation  and  smooth 
operation  with  any  of  the  undesirable  vibrations. 

The  cylinders  are  lubricated  in  a  simple  manner.  The  cylinder'  oil 
flows  by  gravity  to  a  Richardson  Phoenix  sight  feed  oiler  and  from  there 
individual  brass  piping  conducts  the  oil  to  four  points  in  each  cylinder 
wall.  These  points  are  located  a  little  below  the  center  of  the  piston 
when  it  is  at  the  top  of  its  stroke.  Thus  oil  is  not  carried  to  the  firing 
chamber  by  the  piston  rings  nor  carried  to  the  pump  by  the  wiper  ring. 

The  piston  pin  lubrication  is  one  of  the  special  positive  feed  systems 
on  the  Fulton  engine.  The  oil  line  leading  to  the  sight  feed  oilers  for 
the  main  bearings  is  tapped  just  below  the  shut-off  valve.  From  that 
point  a  smaller  pipe  with  a  single  sight  feed  adjusting  valve  runs  down 
to  a  point  inside  the  "A"  frame  just  below  the  bottom  edge  of  the  cyl- 
inder liner.  At  this  point,  fastened  to  the  "A"  frame  by  bracket,  is  the 
lower  half  of  the  piston  pin  oiler.  This  oiler  is  a  special  apparatus, 
having  a  small  cylinder  containing  a  plunger  that  has  a  hole  bored 
through  its  center.  The  plunger  is  held  by  a  spring  from  beneath.  The 
operation  of  this  mechanism  is  such  that  any  oil  introduced  into  the 
lower  end  of  the  cylinder  is  forced  through  the  hole  in  the  center  of  the 
plunger  by  any  downward  action  of  that  plunger.  This  downward  action 
is  accomplished  by  the  upper  half  of  the  piston  pin  oiler  (consisting  of 
a  check  valve),  which  is  rigidly  attached  to  the  inside  of  the  engine's 
piston  skirt  at  its  bottom  edge,  striking  the  oiler's  cylinder  plunger  at 
the  end  of  each  downward  stroke  of  the  piston.  By  an  adjusting  screw 
on  the  oiler,  the  stroke  of  the  oiler's  plunger  can  be  regulated  from 
about  one-fourth  of  an  inch  to  any  small  fraction  of  an  inch,  depending 
upon  the  amount  of  oil  desired  to  reach  the  piston  pin.  The  upper  half 
of  this  oiler  (the  part  attached  to  the  engine's  piston)  is  screwed  to  the- 
end  of  a  pipe  that  runs  up  the  inside  of  the  piston  and  direct  to  the 
piston  pin.  Thus  the  oil  flows  by  gravity  to  the  lower  half  of  the  piston 
pin  oiler  and  from  there  is  forced  direct  to  the  piston  pin  by  a  positive 
feed,  controlled  by  regulating  the  stroke  of  the  oiler's  plunger  and  by 
the  amount  of  oil  the  operator  allows  to  flow  to  the  oiler. 

The  reliability,  continuity  of  operation,  maintenance,  etc.,  of  the 
Fulton  Diesel  Oil  Engines,  are  on  a  parity  with  those  of  a  high  grade 
steam  plants  of  corresponding  capacity.  In  fact,  the  results  achieved 
show  that  the  maintenance  is  even  very  much  less  than  that  of  a  steam 
plant  of  corresponding  capacity,  with  the  added  advantage  of  low  labor 
and  fuel  costs.  The  investment  charges  are  approximately  the  same 
on  this  market  as  for  a  fully  and  modernly  equipped  steam  plant, 
which,  of  course,  takes  into  consideration  the  entire  property,  including 
building. 


262  DESCRIPTION  OF  DIESEL  ENGINES 


THE   NORDBERG-CARELS   DIESEL    ENGINE 

The  Nordberg-Carels  Diesel  Engine  is  an  improved  development  of 
the  well  known  Carels  engine  of  Belgium,  the  Nordberg  Manufacturing 
Company  of  Milwaukee,  Wisconsin,  having  secured  rights  to  build  this 
engine  from  Carels  Brothers,  of  Ghent,  Belgium.  The  engines  are  of  the 
two-cycle  type. 

The  engines  range  in  size  from  750  to  3000  B.H.P.,  and  in  units  of 
from  three  to  six  cylinders.  The  larger  engines  have  cylinders  of  500 
B.H.P.  each,  being  the  largest  size  built  in  America.  "The  engines  are  of 
the  vertical,  heavy  duty  type,  with  crossheads  and  open  frame.  All 
engines  operate  at  relatively  slow  speeds,  a  feature  which  promotes  long 
life  of  the  engine  and  a  minimum  of  time  lost  in  shut-downs  for  repairs 
or  overhauling.  This  is  of  special  importance  in  marine  installations, 
reducing  expensive,  delays  in  port  and  serious  breakdowns  at  sea. 

All  the  above  engines  have  cam  actuated  scavenging  valves  in  .the 
cylinder  heads.  A  smaller  engine  has  been  developed  by  the  Nordberg 
Manufacturing  Company,  of  the  port  scavenging  type;  that  is,  air  is  in- 
troduced into  the  cylinder  'by  the  movement  of  the  piston,  uncovering  a 
series  of  ports  in  communication  with  the  scavenging  pump. 

Inasmuch  as  the  Carels  engine  follows  the  two-cycle  construction, 
the  method  of  scavenging  follows  similar  systems  adopted  on  modern 
engines  of  this  respective  construction.  The  older  system  of  providing 
scavenging  valves  in  the  cylinder  head  appears  to  be  abolished  in  most 
two-cycle  Diesels,  ports  being  provided  at  the  bottom  of  the  cylinder, 
uncovered  >by  the  piston  in  arrangement  with  auxiliary  valve-controlled 
air  ports  usually  joist  above  the  main  ports. 

Following  is  a  tabulation  of  the  several  sizes  and  types  built  by  the 
Nordberg  Manufacturing  Company: 


Type 
3  V.E. 

B.  H.  P. 

Sea  Level 
Rating 
330 

Type 
Scavenging 

Port 

Speed 
Stationary 
Units 
225 

4  V.E. 

440 

Port 

225 

5  VE 

550 

Port 

225 

6  V.E. 

660 

Port 

225 

3  E.G. 

750 

Valves 

180 

4  E.G. 

1000 

Valves 

180 

5  E.G. 

1250 

Valves 

180 

3  F.H. 

1500 

Valves 

120 

4  F.H. 

2000 

Valves 

120 

5  F.H. 

2500 

Valves 

120 

6  F.H. 

.    3000 

Valves 

120 

DESCRIPTION  OF  DIESEL  ENGINES 


263 


In  the  case  of  marine  engines  direct  connected  to  the  propeller  shaft, 
•the  above  engine  speeds  are  reduced  to  suit  lower  propeller  speeds,  the 
stroke  being  lengthened  to  compensate.  In  electric  marine  drives  the 
above  standard  ispeeds  are  maintained. 

Two-cycle  engines  are  particularly  well  adapted  for  continuous  oper- 
ation with  low  grade  fuels.  This  is,  because  there  are  no  exhaust  valve 
seats  subjected  to  intense  heat  or  to  become  pitted  or  corroded  with 
heavy  oil  residue,  necessitating  frequent  shutdowns  for  cleaning  and  re- 
fitting of  valves. 

The  following  is  the  fuel  consumption  based  on  oil  of  18500  B.T.U. 
per  lb.,  using  any  quantity  of  fuel  free  from  water: 


Load 
Lbs.  Oil  per  B.H.P.  per  hr.. 


Full 
0.45 


H 

0.47 


72 

0.51 


One  B.H.P.  is  secured  from  about  8,000  B.T.U.,  which  corresponds  to 
over  750  B.H.P.  hours  per  barrel.  Lubricating  oil  consumption  ranges 
from  .001  lb.  per  B.H.P.  hr.  for  large  units  to  .0015  Ibs.  for  smaller  units. 

Following  is  a  tabulation  of  cooling  water  required. 


Inlet 
Temp. 
50 

95° 
7.2 

100° 
6.5 
7.2 
8.1 
9.2 
10.8 
13.0 
16.2 
21.6 
32.4 

Discharge 
105°   110° 
5.9     5.4 
6.5     5.9 
7.2     6.5 
8.1     7.2 
9.2     8.1 
10.8     9.2 
13.0    10.8 
16.2    13.0 
21.6    16.2 
32.4    21.6 

Temperature 
115°    120° 
5.0     4.6 
5.4     5. 
5.9     5.4 
6.5     5.9 
7.2     6.5 
8.1     7.2 
9.2     8.1 
10.8     9.2 
13.0    10.9 
16.2    13.0 

125° 
4.3 
4.6 
5. 
5.4 
5.9 
6.5 
7.2 
8.1 
9.2 
10.8 

130 
4.1 
4.3 
4.6 
5. 
5.4 
5.9 
6.5 
7.2 
8.1 
9.2 

55 

8.1 

60 

__   9.2 

65  _ 

10.8 

70 

13.0 

75 

16.2 

80 

21.6 

85 

32.4 

90 

Nordberg  Diesel  engines  include  direct  connected  generator  units  for 
central  municipal  and  industrial  power  stations,  also  direct  connection 
to  Nordberg  two-stage  air  compressors,  centrifugal  pumps,  belt  drive  to 
ammonia  compressors,  gear  drive  to  plunger  pumps,  etc. 

Details  of  Construction:  The  illustrations  show  the  general  design 
of  the  Nordberg  engine.  It  will  be  noted  that  open  frame  construction 
has  been  adopted  on  this  type  of  Diesel.  This  renders  the  running  gear 
easily  accessible  for  inspection.  However,  the  openings  between  frames 
are  closed  by  means  of  light  weight,  oil  tight,  removable  guards. 

Bedplates  are  of  the  closed  pit  tyipe  for  collection  of  lubricating  oil. 
Cylinder  barrels  consist  of  removable  liners,  at  the  middle  of  which  are 


264 


DESCRIPTION  OF  DIESEL  ENGINES 


located  the  exhaust  ports.  Cylinders,  heads,  pistons,  exhaust  pipes,  cross- 
head  pins  and  cross-head  guides  are  water  cooled.  The  absence  of  ex- 
haust valves  in  two  cycle  engines  simplifies  the  construction  of  the  cyl- 
inder head  and  renders  the  cooling  of  it  more  uniform,  thus  eliminating 
danger  of  cracking.  This  is  often  the  case  when  the  construction  of 
Diesels  is  such  that  sudden  heat  temperatures  or  lack  of  cooling  seriously 
effects  the  plant,  causing  damage. 


Cross-Sectional  Vieic  Through  Nordberg  Engine.  Note  Coolers,  Air  Suc- 
tion Regulating  Valve,  Water  Circulating  System,  Crosshead  Guides, 
Scavenging  Values,  etc. 

Locating  the  scavenging  valves  in  the  cylinder  head  considerably 
strengthens  the  head  and  placing  scavenging  valves  as  found  on  the 
Nordiberg-Carels  engine  makes  very  effective  and  uniform  cooling. 

The  use  of  crosshead  allows  a  larger  clearance  between  cylinder  ana 
piston,  eliminating  all  danger  of  the  piston  seizing  in  the  cylinder.  In 
particular  should  this  be  beneficial  when  the  engine  is  working  under 
heavy  load  or  prepared  to  be  shut  down.  The  importance  of  this  detail 
can  hardly  be  over-estimated,  as  serious  accidents  have  occurred  in  the 
so-called  "trunk-piston"  design. 


DESCRIPTION  OF  DIESEL  ENGINES  265 

A  special  feature  of  the  Nordberg  engine  is  the  crankshaft,  which  is 
of  the  "built  up"  type.  The  crank  pin  and  crank  webs  are  made  from 
one  solid  forging  and  the  shaft  sections  pressed  in  and  keyed. 

This  construction  is  highly  commendable  and  adds  to  the  perma- 
nency of  this  engine. 

Fuel  atomizing,  scavenging,  and  air  starting  valves  are  shown  in 
cross-sectional  illustration.  The  fuel  valve  is  of  the  closed  type,  the 
needle  of  which  is  closed  by  means  of  an  outside  spring  and  opened  by 
a  cam.  This  needle  is  easily  removable  for  inspection  without  taking 
the  balance  of  the  valve  apart.  The  fuel  valve  is  adapted  to  handle  fuels 
varying  from  a  very  light  oil  down  to  high  asphaltum  such  as  Mexican 
fuel  oil,  and  those  of  similarity  on  ithe  Pacific  Coast  of  12°  Baume. 

Each  cylinder  is  provided  with  its  own  fuel  pump,  which  is  of  the 
plunger  type,  eccentric  driven  from  the  cam  shaft.  Any  pump  can  be 
cut  out  independently  of  the  others  and  inspected  while  the  engine  is  in 
operation.  Means  for  priming  are  provided. 

Close  and  accurate  regulation  is  obtained  by  the  use  of  a  (Sensitive, 
rigidly  constructed  type  of  governor,  driven  'by  the  cam  shaft  by  means  of 
an  elastic  drive,  making  the  rotation  of  the  governor  uniform  and  ithus 
increasing  its  accuracy.  The  regulation  of  the  engine  speed  is  accom- 
plished by  varying  the  quantity  of  the  fuel  oil  introduced  to  the  fuel 
valve.  The  governor  acts  upon  the  fuel  pump  by  passing  the  fuel  in 
greater  or  less  quantities,  according  to  the  power  demand. 

Air  for  starting  and  fuel  atomizing  is  supplied  by  a  three  stage 
single  acting  compressor,  direct  connected  to  the  engine  and  provided 
with  inter-coolers.  Compressor  valves  are  of  circular  plate  type,  no 
valve  gear  being  required. 

The  engines  are  provided  with  an  automatic  oiling  system  complete 
with  filter,  pumps,  etc.  Cylinders  are  lubricated  'by  independent  mechan- 
ically operated  oil  pumps.  In,  addition  to  having  feeds  from  the  oiling 
system,  the  main  bearings  are  of  the  ring  oiling  type.  A  cooling  coil  is 
provided  in  the  overhead  tank  to  insure  proper  cooling  of  lubricating  oil. 

A  fuel  oil  filter  and  fuel  heating  arrangement  is  included.     Fuel  oil 
passes  from  the  filter  to  the  fuel  pumps  through  a  heated  header. 


266 


DESCRIPTION  OF  DIESEL  ENGINES 


MclNTOSH   &  SEYMOUR   DIESELS 

In  the  illustration  of  the  Mclntosh  &  Seymour  390  indicated  horse- 
power engine,  a  type  of  light  but  strong  construction  is  .shown.  In  par- 
ticular the  accessibility  to  vital  parts  during  operation  will  be  noticed. 
Both  frame  and  base  are  well  ribbed  to  insure  the  proper  stiffness  and 
strength.  On  this  size,  the  cylinders  and  frame  are  cast  in  one  piece,  the 
cylinders  being  arranged  in  sets  of  three.  (Chapter  VIII,  page  166). 


1Z440 


Diagram  of  Kingsoury  Thrustbearing  Extensively  Used  on  Medium  Sized 
Mclntosh  &  Seymour  Diesel  Engines  With  Great  Results 

The  control  consists  of  only  two  levers,  one  to  control  the  fuel  and 
starting  air,  and  the  other  the  maneuvering.  The  first  half  of  the  move- 
ment of  the  fuel  lever  on  the  quadrant  controls  the  stroke  of  the  fuel 
pumps,  which  regulates  the  amount  of  fuel  delivered  to  the  cylinders  and 


DESCRIPTION  OF  DIESEL  ENGINES  267 

consequently  the  speed  of  the  engine;  the  second  half  of  the  movement 
is  used  in  starting.  This  opens  the  relay  valve  and  admits  the  starting 
air  to  the  cylinders.  The  reversing  is  accomplished  by  turning  'the  re- 
versing wheel.  This  can  be  done  in  a  short  time,  as  from  three  to  five 
seconds. 

The  attached  compressor  is  driven  from  the  forward  end  of  the  crank- 
shaft. This  ooinipress'or  is  'three  stage  and  the  air  is  thoroughly  cooled 
between  the  stages  and  after  the  high  stage,  by  inter-and  after-coolers. 

A  Kingsbury  thrust  bearing  is  attached  directly  to  the  base  of  the 
engine.  This  thrust  bearing  is  of  the  late  type  and  is  noted  for  its  relia- 
bility and  efficiency. 

In  the  illustration  of  the  1200  I.H.P.,  such  as  installed  on  the  Motor 
Ship  "Kennecott",  it  represents  the  cross-head  type  of  Marine  Engine. 

The  bases  have  the  same  arrangement  of  bearing  girder  that  the 
smaller  engines  have,  which  gives  the  base  great  stiffness,  so  imperative 
in  marine  engineering.  The  engine  is  arranged  with  individual  frames, 
each  frame  being  of  the  same  general  arrangement  as  the  corresponding 
section  of  the  box  frame  on  the  smaller  engines. 

These  individual  frames  are  held  tight  together  on  the  front  by  the 
guide  plate,  which  is  attached  at  the  top  and  bottom  with  fitted  bolts  and 
on  the  back  by  a  tie  plate  also  tolted  by  fitted  bolts;  this  tie  plate  being 
arranged  to  carry  the  cooling  water  pipes  for  the  pistons.  All  of  these 
crosshead  type  engines  are  arranged  for  water-cooled  pistons,  as  when 
cross-heads  are  used,  the  piston  >cooling  'piping  can  be  so  arranged  that 
there  will1  be  no  chance  for  any  cooling  water  to  get  into  the  lubricating 
oil.  A  diaphragm  is  fitted  below  the  cylinder  with  a  packing  ring 
around  the  piston  rod  so  that  no  water  can  get  into  the  working  parts, 
and  this  also  prevents  any  excess  lubricating  oil  from  getting  on  the 
cylinders,  so  that  pressure  lubrication  can  be  used  on  the  working  parts 
if  it  is  so  desired. 

Wtith  the  cross-head  type  engine,  the  maneuvering  is  accomplished  by 
means  of  air  cylinders  or  an  electric  motor  in  designated/  construction. 
The  ifuel  being  shut  off,  the  maneuvering  gear  first  removes  the  cam 
rollers  from  the  cams,  then  moves  the  cam  shaft  endways  in  similarity 
to  the  smaller  types,  placing  the  other  set  of  cams  under  the  roller;  then 
it  puts  the  rollers  back  on  the  cams;  the  gear  being  so  arranged  that 
when  this  is  accomplished  the  fuel  lever  can  be  operated  and  the  engine 
started. 

It  will  be  interesting  here  to  give  some  minor  details  on  the  accom- 
plishment of  the  Mclntosh  &  Seymour  engines  on  the  "Kennecott."  The 
ship  was  built  by  the  Todd  Drydock  &  Construction  Company,  in  1921, 
for  the  Alaska  Steamship  Company.  It  has  a  length  of  345  feet,  a  beam 
of  49  feet  6  inches,  and  a  loaded  draft  of  22  feet.  This  vessel  is  equipped 
with  two  Mclntosh  &  Seymour  Heavy  Duty  cross-head  type  Diesel  marine 
engines  of  1,200  indicated  horsepower  each,  with  a  nominal  full  load 
speed  of  140  R.P.M. 


268 


DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES  269 

All  the  'auxiliaries  on  this  vessel  are  electrically  driven,  in  simi- 
larity to  the  M.  S.  Solitaire,  illustrated  in  other  pages,  there  being  no 
boiler  on  the  vessel.  Electricity  is  furnished  by  two  Mclntosh  t&  Sey- 
mour 100  B.H.P.  Diesel  electric  generating  sets,  one  of  these  being  in 
operation  at  sea,  which  drives  all  the  auxiliaries  as  well  as  taking  care 
of  such  heating  as  there  may  be.  Two  of  these  engines  are  used  in  port 
for  operating  the  winches.  This  vessel  has  a  deadweight  tonnage  of 
6y560,  and  it  averages  a  little  over  Wy2  knots  at  sea,  fully  loaded,  and 
has  a  fuel  consumption  of  about  lQ*/2  tons  per  day  of  regular  16  gravity 
boiler  fuel  oil. 

It  has  been  found  with  the  electric  winches  on  the  "Kennecott,"  that 
she  can  handle  cargo  50  per  cent  faster  than  with  steam  equipment  and 
with  a  fuel  consumption  when  in  port  of  four  barrels  per  day. 

Commercially,  the  "Kennecott"  is  of  interest  from  the  fact  that  it 
can  make  money  at  rates  where  a  steam  vessel  has  to  be  operated  at  a 
loss. 

The  illustration  of  the  Mclntosh  &  Seymour  Diesel  engine  gives  an 
excellent  view  of  the  modern  type  of  this  respective  make.  While  in 
smaller  sizes  the  trunk  piston  is  preferred,  nevertheless  in  larger  classi- 
fication the  cross-head  type  seems  to  find  greater  favor.  The  general 
construction  of  Mclntosh  &  Seymour's  engines  are  exceedingly  rigid. 
The  base  is  made  very  stiff  by  arranging  the  bolting  between  the  frame 
and  the  base  so  as  to  give  a  very  short,  effective  length  of  the  bearing 
girder,  giving  great  strength  and  stiffness  with  a  minimum  depth  of  base. 

The  frame  is  of  the  box  type,  with  large  openings  for  each  crank, 
and  the  ribs  which  form  the  sides  of  these  openings  extend  clear  across 
the  frame  with  an  arch  over  the  bearing  cap,  which  gives  a  frame  of 
great  stiffness  and  rigidity  with  a  minimum  weight. 

On  the  small  sizes,  the  cylinder  jackets  are  cast  in  one  piece  with 
this  box  frame,  and  on  the  larger  sizes  the  cylinders  are  cast  separately 
and  bolted  to  the  frame. 

The.  air  compressor  is  of  the  three  stage  type  and  is  driven  from  an 
overhung  crank  on  the  forward  end  of  the  crankshaft.  The  trunk  piston 
types  of  engine  have  forced  feed  lubrication  for  the  cylinders,  piston 
pins  and  the  compressor,  and  have  gravity  pressure  lubrication  for  the 
main  bearings  and  crank  pins  so  as  to  avoid  any  excess  lubricating  oil 
getting  in  the  cylinders. 

The  smaller  sizes  of  trunk  piston  type  of  engines  are  maneuvered  by 
hand.  The  fuel  being  >shut  off,  the  first  turn  of  maneuvering  hand  wheel 
removes  the  camrollers  from  the  cams,  the  next  two  turns  of  the  wheel 
moves  the  cam  shaft  endways,  placing  another  set  of  cams  under  the 
rollers,  and  the  fourth  turn  puts  the  cam  rollers  back  on  the  cams;  the 
gear  being  so  arranged  that  until  this  operation  is  complete,  the  fuel 
lever  cannot  be  moved. 

To  demonstrate  the  ease  of  maneuvering  the  Mclntosh  &  Seymour 
engines  of  the  trunk  type,  we  will  refer  back  to  this  subject.  The  con- 
trol consists  of  only  two  levers,  one  to  control  the  fuel  and  starting  air, 


270 


DESCRIPTION  OF  DIESEL  ENGINES 


and  the  other  the  maneuvering.  The  first  half  of  the  movement  of  the 
full  lever  on  the  quadrant  controls  the  stroke  of  the  fuel  pumps,  which 
regulates  the  amount  of  fuel  delivered  to  the  cylinder  and  consequently 
the  speed  of  the  engine;  the  second  half  of  the  movement  is  used  in 
starting.  This  opens  the  relay  valve  and  admits  the  starting  air  to  the 
cylinders.  The  reversing  is  accomplished  by  turning  the  reversing  wheel. 
Three  turns  of  the  wheel  is  all  that  is  necessary  to  completely  reverse 
the  engine.  This  can  be  done  in  ias  short  a  time  as  from  three  to  five 
seconds.  A  Kingsbury  thrust  bearing  is  attached  directly  to  the  base  of 
the  engine.  This  thrust  bearing  is  of  the  latest  type  and  is  noted  for  its 
reliability  and  efficiency. 

COMPARISON   TABLE   OF  THERMAL   EFFICIENCY,   OVER   ALL 

Of  Diesel  Station  and  Three  Types  of  Steam  Stations,  all  Operated  Under 

the  Same   Management. 

(Mclntosh  &  Seymour  Diesel) 

Plant  A          Plant  B             Plant  C  Plant  D 

Rating  of  plant 1050  kw.        1300  kw.              1050  1055 

Type  of  plant Diesel         Steam  Tur.       Steam  Eng.  Gas  Engine 

Number  of  units 333  4 

Fuel  used--                           Oil         Oil  and  Coal     Gas  and  Coal  Gas 


Average  station 

factor,  per  cent: 

96.6  11,734 

71.8   11,822 

49.0   __. 

46.3 .__   13,556 

34.0  

32.0   

23.6   _  .    18,203 


B.  T.  U.  per  KW.  Hour 


27,000 


43.200 


26.100 


REPORT  OF  TEST  ON   MclNTOSH  &  SEYMOUR  DIESEL  ENGINE 

(500  B.H.P.)    IN  A   MODERN   POWER   PLANT  OPERATING 

MANUFACTURING   ESTABLISHMENT. 


Percentage  of  rated  load ___  25.6  51.0 

Revolutions   per   minute _  168  167 

Brake  horse  power 128.2  255 

Time  of  test  (in  hours) %  Vz 

Fuel  consump.  per  B.H.P.-Hr.    (Ibs.) 584  .432 

Injection  pressure    (Ibs.) 750  775 

Exhaust   gas    appearance Clear  Clear 

Inlet  temp,  of  cooling  water   (°P.) 69  69 

Outlet  temp,  of  cooling  water  (°F.) 150  150 

Temperature  in  testing  room   (°F.) 73  73 


75.8  99.6  114.8 

166  163  168 

379  498  574 

%  1  1 

.396  .393  .388 

800  800  900 

Clear  Clear  Clear 

69  69  69 

158  158  158 

72  78  79 


DESCRIPTION  OF  DIESEL  ENGINES 


271 


272 


DESCRIPTION  OF  DIESEL  ENGINES 


DETAILED   DESCRIPTION   OF   NELSECO   MARINE  AND  STATIONARY 

DIESEL   ENGINES. 

As  will  be  observed  in  accompanying  illustrations  of  the  600  B.H.P. 
Nelseco  engine,  the  six  working  cylinders  of  the  engine  are  in  line  with 
the  single  three  stage  air  compressor  at  the  forward  end.  Forward  of 
the  air  compressor  is  the  fuel  pump  and  governor.  The  bedplate  and 
housing  are  of  exceptionally  rigid  design  and  construction,  the  housing 
being  carried  right  up  to  the  tops  of  the  cylinders  and  the  cylinder-liners 
forced  into  the  housing  with  a  space  between  which  forms  the  water- 
jacket.  Detachable  cylinder-heads  are  bolted  directly  to  the  top  of  the 
housing.  All  of  the  valves  in  the  cylinder  head  are  arranged  horizontally, 
and  are  operated  from  the  camshaft,  which  is  carried  in  brackets  on  the 
side  of  the  housing  by  means  of  vertical  rocker  arms. 


Section  Through  Working  Cylinder  of  Nelseco  600  B.H.P.  Engine. 


DESCRIPTION  OF  DIESEL  ENGINES 


273 


With  this  design  there  is  a  space  of  about  six  inches  between  the 
injection  valve  nozzle  and  the  piston  top,  which  aids  good  combustion  and 
prevents  burning  and  cracking  of  the  pistons. 

It  has  been  suggested  that  undue  wear  of  the  lower  side  of  the 
valve-stems  may  be  caused  by  the  weight  of  the  valve  being  constantly 
borne  at  one  point,  but  in  actual  practice  this  has  not  transpired,  nor  is 
any  detrimental  effect  anticipated  by  the  designers. 

The  camshaft  and,  much  of  the  valve  gear,  are  enclosed  in  a  casing 
and  driven  by  a  train  of  spur-gears  from  the  crankshaft,  located  in  the 
middle  of  the  engine  between  working  cylinder  numbers  three  and  four. 

We  will  mention  that  the  bearings  at  both  ends  of  the  connecting 
rod,  as  well  as  every  other  important  bearing  on  the  engine,  are  adjust- 
able, which  is  an  important  feature  in  the  case  of  a  marine-engine,  where 
shims  occasionally  have  to  be  taken  out.  Large  openings  are  provided 
in  the  sides  of  the  housing  to  permit  a  free  access  to  the  crankcase. 


Section  Through  A.  C.  Cylinder  o/  600  B.H.P.  Nelseco  Diesel  Engine. 


274 


DESCRIPTION  OF  DIESEL  ENGINES 


"b    o 

o    w 


8 

I 


DESCRIPTION  OF  DIESEL  ENGINES 


275 


As  already  stated,  the  air  compressor  is  of  the  three  stage  type.  In 
this  case  the  piston  is  driven  from  the  crankshaft  by  means  of  a  con> 
necting  rod  and  cross  head.  Advantage  is  taken  of.  this  opportunity  to 
separate  the  compressor  cylinders  entirely  from  the  crankcase,  provid- 
ing an  accessible  machine  as  well  as  avoidance  of  all  trouble  due  'to 
lubricating  oil  in  the  cylinders,  which  was  a  fault  found  too  frequently 
in  early  Marine  Diesel  engines,  and  occasionally  met  with  even  today. 

For  fuel  injection,  fuel  pumps  provide  a  separate  plunger  for  each 
working  cylinder,  and  is  driven  directly  from  the  crankshaft  by  means 
of  a  vertical  shaft  and  suitable  gearing.  On  this  vertical  shaft  is  mounted 
the  governor,  which  is  of  the  constant-speed  type  for  engines  designed 
to  drive  generators,  and  of  the  limit-speed  type  for  direct-connected 
marine  engines.  All  controls  and  also  the-  reversing  gear  for  the  directly 


Nelseco  600  B.H.P.,  200  R.P.M.  Diesel  Engine,  looking  astern. 
Note  the  valve  actuating  arrangement. 


276 


DESCRIPTION  OF  DIESEL  ENGINES 


reversible  marine  engines  are  located  at  the  forward  end  of  the  engine 
and  on  the  upper  platform,  that  is,  at  the  fuel  pump  and  air  compressor 
end,  and  here,  of  course,  the  operator's  station  is  located.  In  the  case  of 
generator  engines,  only  three  cylinders  are  fitted  with  air  starting  valves, 
but  for  direct  reversible  engines  it  is  necessary  to  fit  all  of  the  working 
cylinders  with  air  starting  valves.  Starting  air  for  this  purpose  is  taken 
from  storage  tanks,  and  a  maximum  of  350  pounds  pressure  is  used. 

Independently  driven  circulating  water  and  lubricating  oil  pumps 
are  provided,  as  the  Nelseco  designers  consider  this  the  most  satisfactory 
method,  but  provision  is  made  for  fitting  direct  connected  pumps  at  the 
forward  end  of  the  engine  in  such  special  cases  as  it  may  seem  advisable 
or  necessary.  Provision  is  made  for  ample  water  jackets  on  all  parts  of 
the  engine  which  require  cooling,  and  the  arrangements  of  connection 
areas  are  such  that  there  is  a  free  flow  of  circulating  water  from  the 
inlet  to  the  overboard  discharge  from  the  exhaust  headed  jacket. 


Section  Through  Cam  Shaft  Gear  Compartment  o/  Nelseco  600  B.  H.  P. 
200  R.P.M.  Diesel  Engine. 


DESCRIPTION  OF  DIESEL  ENGINES 


277 


For  the  lubricating  of  the  engine,  the  system  used  can  best  be  de- 
scribed by  calling  it  a  gravity  forced-feed.  With  this  system  the  lubri- 
cating oil  flows  from  the  gravity  tank,  which  is  at  a  sufficient  height 
above  the  engine  crankshaft  to  give  the  proper  pressure  to  the  main 
bearings,  then  through  holes  in  the  crankshaft  to  the  crankpins,  and  up 
the  inside  of  the  connecting  rods  to  the  wrist  pins.  The  crankcase  is 
enclosed  and  all  surplus  oil  drains  to  a  suitable  formed  trough  in  the 
bottom  of  the  bedplate  from  whence  it  is  pumped  back  through  suitable 
strainers  to  the  gravity  tank.  All  of  the  important  bearings  are  thus 
under  forced  lubrication  and  a  free  flow  of  oil  is  circulating  through 
them  at  all  times. 


Oil  Pump  Arrangement  of  Ntlseco  600  B.  H.  P.  200  R.  P.  M. 
Diesel  Engine. 


278  DESCRIPTION  OF  DIESEL  ENGINES 

The  camshaft  parts  are  oiled  by  splash  from  oil  carried  in  the  bottom 
of  the  trough  of  the  camshaft  casing.  All  cylinders  and  exhaust  valves 
stems  are  taken  care  of  by  mechanical  oilers,  and  the  minor  valve  gear 
bearings  are  fitted  with  oil  cups  for  hand  oiling. 

For  large  freighters,  passenger  vessels  and  tankers  up  to  about  12,000 
tons  D.W.C.,  and  4,000  H.P.,  this  engine  is  made  non-reversible  and  used 
in  conjunction  with  electric  transmission.  In  these  cases  several  engines 
make  up  the  total  power  required,  although  any  one  <unit  would  be  suffi- 
cient to  bring  the  vessel  home  at  reduced  speed  in  case  of  accident  to 
the  others.  At  the  same  time  it  must  be  pointed  out  that  a  totally  dis- 
abled modern  direct  driven  Diesel  ocean  motorship  is  practically  un- 
heard of  today. 

For  Diesel  electric  drive  of  a  cargo  ship  requiring  2,000  shaft  H.P. 
(about  2,600  l.H.P.)  four  of  these  600-700  B.H.P.  units,  each  connected 
to  a  400  K.W.  electric  generator,  may  be  installed  in  the  engine  room 
and  these  are  capable  to  provide  the  current  for  a  single  electric  pro- 
pelling motor.  Control  of  the  latter  can  be  placed  on  the  navigation 
bridge,  or  at  lany  other  part  of  the  ship  independent  from  the  engine  room, 
thus  eliminating  delays  or  misunderstandings  when  maneuvering. 

For  detailed  description  on  this  arrangement  the  readers  are  advised 
to  study  the  chapter  dealing  with  "Electric  Propulsion,"  pertaining*  to 
the  trawler  "Mariner,"  which  is  propelled  by  twin-240  B.H.P.  Nelseco 
Diesel  engines. 

This  engine  has  been  built  under  Lloyd's  survey,  and  is  designed  to 
meet  Lloyd's  and  American  Bureau  of  Shipping  requirements  in  every 
way.  In  the  following  table  iti  is  intended  to  show  actual  performance 
of  this  type  of  Nelseco  engine  in  runs  at  constant  speed  and  various 
powers,  illustrating  its  fuel  consumption: 


FUEL  CONSUMPTION— CONSTANT  SPEED 
(In  pounds  per  B.  H.  P.  hour) 

25   per   cent   over-load „ .42 

Full   load   .42 

Three-fourths   load    , .45 

One-half   load    .51 

One^fourth   load   .67 

This  table  shows  the  flat  fuel  consumption  curve,  which  is  charac- 
teristic of  the  Diesel  engine.  To  give  an  idea  of  the  overload  capacity 
of  this  engine,  it  can  be  stated  that  it  carried  for  a  short  time  a  load  of 
875  B.H.P.  with  only  a  very  slight  amount  of  smoke  showing  in  the  ex- 
haust. This  shows  the  conservativeness  of  the  600  B.H.P.  rating.  In 
fact,  the  engine  is  fully  capable  of  developing  10  per  cent  overload 
almost  continuously.  Another  run  was  made  with  the  revolutions  vary- 


DESCRIPTION  OF  DIESEL  ENGINES 


279 


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A 

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5  II 

&«' 


280  DESCRIPTION  OF  DIESEL  ENGINES 

ing  as  they  did  when  direct  connected  to  a  propeller  aboard  ship,  and  it 
was  found  that  with  the  speed  reduced  to  about  two-thirds  when  the 
toad  would  foe  approximately  only  one-quarter  that  of  full  power,  the 
consumption  of  fuel  was  only  about  .52  Ibs.  per  horsepower.  The  marine 
fuel  consumption  curves  are  thus  much  flatter  than  the  fuel  consumption 
curve  when  operating  on  a  generator.  The  mechanical  efficiency  of  the 
engine  proved  to  be  very  excellent  indeed,  and  at  full  power  it  was  just 
under  80  per  cent.  Governor  trials  were  also  held  and  it  was  found  that 
from  full  load  to  no  load  there  was  only  about  a  Zy2  per  cent  variation 
in  revolutions.  When  the  load  was  thrown  on  or  off  suddenly  there  was 
practically  no  momentary  jump  in  revolutions  except  when  full  load  was 
thrown  on  or  off,  and  then  the  first  surge  amounted  to  only  a  few  revo- 
lutions more  than  the  speed  at  which  the  engine  finally  settled.  In  fact, 
the  governor  performance  appeared  to  be  given  the  service  in  every  way. 


281 


End  View  of  Burmeister  &  Wain  Diesel.     Note  Gear,  Valve  Arrangement, 
Engine  Control  Lever,  Etc. 


282 


DESCRIPTION  OF  DIESEL  ENGINES 


BURMEISTER   &  WAIN'S   DIESEL   ENGINES 
(Marine  Type) 

Burmeister  &  Wain's  Diesel  engines  are  a  convincing  factor  of  mod- 
ern development  in  Diesel  construction.  Engines  of  this  type  may  be 
found  in  all  respective  classes  of  ships  of  Europe's  Merchant  Marine  as 
well  as  of  America's.  The  engines  follow  the  four-cycle  construction. 

To  gain  some  idea  on  advanced  methods  of  Burmeister  &  Wain's 
engines,  a  brief  description  is>  herewith  given  of  late  -adopted  styles  of 
engines  for  cargo-carriers  of  5,000  to  6,000  tons  displacement. 

In  this  type  of  vessel  the  average  daily  fuel  consumption  is  about  25 
tons  of  oil.  The  average  speed  is  calculated  on  11  knots  per  hour.  The 
engine  and  propeller  speed,  80  R.P.M.  Engine  room  crew  of  15  men. 

The  dimensions  are  I.H.P.  1,750;  shaft  H,P.  cylinder  diameter  24.803 
in.;  stroke  51.181  in.;  revolutions  100;  length  from  aft  coupling  to  front 
of  compressor  10,500  mm.;  height  from  center  of  crankshaft  to  top  of 
valves  6,600  mm. 

The  most  interesting  features  of  this  new  type  of  engine  are  the 
cylinder  head  and  cylinder  liner.  The  heads  are  nearly  square  and  are 
supported  by  distance  pieces  which  stand  on  the  "A"  frames.  The  heads 


Diagram   of  Burmeister  &  Wain  Marine  Diesel  Engine,   Showing  Front 
View  of  Force-feed  Fuel  Pressure  Pump. 


DESCRIPTION  OP  DIESEL  ENGINES 


283 


are  bolted  together,  three  and  three.  Long  bolts  pass  from  the  main 
frame,  thru  the  "A"  frames  and  distance  pieces,  and  between  the  heads, 
each  nut  pressing  down  on  two  heads.  The  long  bolts  also  have  nuts  at 
the  .top  of  the  "A"  frames.  The  liners  are  bolted  directly  to  the  head, 
without  any  packing,  iron  to  Iron.  Outside  the  liner,  bolted  to  the  head 
with  a  gasket  is  the  water  jacket,  which  packs  off  against  the  liner  near 
the  lower  end  with  a  rubber1  ring.  This  allows  the  liner  perfect  freedom 
to  expand.  The  inner  shell  of  the  cylinder  head  is  well  braced  by  four 
stays.  The  cooling  water  enters  at  the  lower  end  of  the  jacket  and  most 


Diagram  of  Burmeister  &  Wain  Diesel  Engine. 

looking  astern. 


Cross-Sectional  View 


284  DESCRIPTION  OF  DIESEL  ENGINES 

of  it  is  made  to  pass  into  the  cylinder  head  at  the  opposite  side  by  a 
baffle-ring  inside  the  jacket.  The  water  space  in  the  head  is  very  large, 
insuring  effective  cooling  around  all  valves. 

In  order  that  the  removal  of  the  piston  downward  instead  of  by  re- 
moving the  head,  may  not  be  too  complicated,  it  has  been  made  oil-cooled 
instead  of  water-cooled,  as  in  previous  builds. 

To  remove  the  piston,  it  is  brought  almost  to  top  center,  the  cross- 
head  shoe  is  blocked  up,  the  cross-head  bearings  taken  apart,  and  the 
connecting  rod  lowered  by  turning  the  crank  almost  to  bottom  center 
while  lowering  the  upper  end  of  the  connecting  rod  with  a  chiain  hoist, 
so  that  it  rests  on  the  outboard  side  of  the  main  frame.  The  outlet  and 
inlet  valves  are  removed,  eye-bolts  screwed  into  the  piston  head,  and 
the  piston  is  lowered  through  the  top  plate  so  that  the  cross-head  pin 
rests  on  beams  placed  across  the  main  frame.  It  can  then  be  inspected 
or  even  removed.  The  top  plate  differs  from  the  ordinary  construction 
in  thiat  it  has  a  hole  large  enough  to  permit  passage  of  the  piston,  this 
hole  being  closed  by  two  semi-circular  plates,  which  contain  a  scrape- 
ring  for  the  piston  rod. 

The  frame  for  the  gear-train  stands  in  the  center  but  is  separate 
from  the  "A"  frames.  The  three  fore  and  the  three  aft  cylinder  heads  are 
bolted  together  with  horizontal  bolts.  This  construction  allows  the  en- 
gine to  weave  slightly,  too  great  rigidity  having  been  found  detrimental. 

The  main  frame  and  "A"  frame  are  largely  of  "I"  section.  The  air 
compressor  is  of  the  latest  Burmeister  /t  Wain  three  stage  design,  di- 
rectly connected  to  the  crankshaft  at  its  forward  end,  having  its  own 
base  frame  bolted  to  the  main  frame,  though  its  "A"  frame  and  cylinders 
stand  free.  Other  parts  of  the  motor  are  in  general  Burmeister  &  Wain 
standard,  with  such  small  refinements  as  experience  has  made  desirable. 

One  new  feature  of  this  engine  which  deserves  mention  takes  the 
form  of  a  metric  scale  and  hand-control  wheel  regulating  the  clearance 
or  varying  the  lift  of  the  fuel  valves,  enabling  the  engine  to  run  at  very 
slow  speed. 

At  the  after  end  of  the  engine  room  are  the  lubricating  oil  pumps, 
supplying  lubricating  oil  to  the  engine,  while  a  fuel  pump  is  stationed 
near  the  bulk-head  for  the  purpose  of  pumping  the  oil  from  the  tanks  to 
the  daily  service  -tanks. 

It  is  interesting  to  note  that  the  Burmeister  &  Wain  engineers  strict- 
ly adhere  to  the  four-cycle  principle,  and  following  reasons  are  advanced, 
which  impartially  we  are  'giving  here. 

In  the  Diesel  engine,  combustion  and  process  of  work  take  place  in 
the  same  unit,  and  thereby  differs  from  the  steam  engine,  where  the 
combustion  .takes  place  in  the  furnace.  The  heat  is  transferred  to  the 
water  in  the  boiler,  whilst  the  work  is  developed  in  the  engine.  It  is 
therefore  a  well  known  fact,  that  if  the  boiler  is  forced,  furnace  and 
tubes  will  be  affected  by  the  fire  and  the  economy  of  the  plant  be  anni- 
hilated, seeing  that  a  considerable  loss  of  heat  is  caused  by  the 


DESCRIPTION  OF  DIESEL  ENGINES 


285 


products  of  combustion  leaving  the  funnel   without  having  been  cooled 
down. 

The  same  is  the  case  with  the  Diesel  engines.  If  too  great  a  quan- 
tity of  fuel  per  hour  is  combustioned  in  these,  the  surfaces  are  too  in- 
tensely heated,  and  will  become  scorched  and  destroyed,  as  the  heat  can- 
not  penetrate  the  walls  to  the  surrounding  cooling  water.  Also  a  con- 
siderable economical  loss  is  caused,  through  the  -temperature  of  the 
exhaust  gases  being  too  high. 


Diagram,  Showing  Cross-Sectional  View  of  Burmeister  &  Wain  Marine 

Diesel  Engine. 

However,  in  comparing  steam-plants  with  Diesel  plants  a  thorough 
difference  will  be  found,  because  in  a  boiler  the  useful  heat  passes  to  the 
water  through  the  heating  surface,  whereas  in  a  Diesel  engine,  the  lost 


286  DESCRIPTION  OP  DIESEL  ENGINES 

heat  passes  through  the  surface  of  the  cylinder  to  the  cooling  water. 
A  standard  for  the  strain  of  the  boiler  is  how  many  kilograms  of  coal 
are  burned  per  hour  in  proportion  to  the  (principal  dimensions;  likewise 
the  standard  strain  of  the  Diesel  engine  is  how  many  kilograms  of  oil  are 
burned  per  hour  in  proportion  to  its  'principal  dimensions.  It  is  imma- 
terial, whether  this  takes  place  in  a  four-stroke  cycle  or  in  a  two-stroke 
cycle  system.  On  the  other  hand  the  economy  with  which  , the  combus- 
tion takes  place  is  of  the  mo,st  eminent  significance,  because  the  heat, 
which  is  not  transformed  into  useful  work,  i.  e.,  the  heat  lost,  will  partly 
be  passed  through  the  cylinder  walls  to  the  cooling  waiter,  partly  dis- 
appears in  the  heat  of  the  exhaust.  It  is  the  lost  heat  that  strains  the 
most  important  parts  of  the  engine. 

Burmeister  &  Wains  engineers  contend  that  the  four-stroke  cycle 
engine  is  the  most  economical  as  its  consumption  is  15  to  20  per  cent 
less  than  that  of  the  two-stroke  cycle;  consequently  the  four-stroke  cycle 
is  the  type  that  causes  the  least  strain  on  the  material;  the  four  cycle 
system  is  therefore  absolutely  in  their  opinion  to  be  adaptable. 

Upon  entering  more  fully  into  the  details  of  the  two  motor  types, 
the  four  cycle  shows,  compared  to  the  two-cycle,  in  every  respect  advan- 
tages which  in  concentrated  form  are  the  following: 

(1)  The  time  the  inner  surfaces  of  the  cylinder  and  cover  are  ex- 
posed to  the  high  temperature  o£  combustion,  is  in  the  four-cycle  motor 
only  half  the  corresponding  time  of  that  in  the  two-cycle,  the  cooling  of 
the  inner  surfaces  during  the  suction  stroke  is  more  effective  in  the  four- 
cycle motor,  consequently   the  four-cycle   works  as  a  whole   far   cooler 
than  the  two-cycle  at  the  same  development  of  power. 

(2)  In  the  four-cycle  the  piston  speed  allowable  is  higher,  and  as 
the  mean  temperature  is  lower,  the  work  can  be  performed  with  a  higher 
mean  pressure.     Therefore  a  four-cycle  of  the  same  weight  and  outer 
dimensions  develops  the  same  horsepower,  or  more. 

(3)  The   four-cycle   engine   having   no    scavenging   air   pump    with 
appurtenant  air  receivers  nor  any  larger  scavenging  air  channels,  the 
construction  of  the  engine  becomes  more  simple  and  easy.     Dimensions 
are  reduced,  and  the  engine  works  more  noiselessly. 

(4)  The  four-cycle  engine  can  work  more  regularly  at  low  revolu- 
tions, and  is  able  to  go  perfectly  "dead  slow"  as  well  as  any  marine 
steam  engine.    This  is  not  the  case  with  the  two-cycle,  because  the  pres- 
sure of  compression  is  smaller  owing  to  the  pressure  of  the  scavenging 
air  being  reduced,  when  the  engine  is  running  slow. 

(5)  The  whole   valve  gear  of  the  four-cycle   works  with  half   the 
number  of  revolutions  of  that  of  the  'two-cycle,  this  gives  a  softer  and 
more  silent  running  and  less  wear  and  tear  on  the  different  parts. 

(6)  For  the  reason  above  mentioned  not  only  the  additional  quan- 
tity of  oil  used  in  a  two-cycle  engine  to  develop  one  H.P.  is  lost,  but  the 
heat  thus  produced  strains  the  engine  excessively,  shortens  its  life  and 
increases  ithe  overhauling  costs,  so  that  the  additional  consumption  of 
fuel  oil  is  in  more  than  one  sense  lost.     This  is  the  case  particularly  in 


DESCRIPTION  OF  DIESEL  ENGINES  287 

large  engines  of  high,  horsepower,  by  reason  of  the  large  cylinder  dimen- 
sions requiring  proportionately  heavier  castings  and  consequently,  it 
is  very  important  not  to  conduct  greater  quantities  of  heat  than  neces- 
sary through  the  cylinder  walls  in  order  not  to  strain  the  material. 

The  deitails  of  the  marine  Diesel  engine  are  designed  with  the  par- 
ticular requirements  of  each  single  part  in  veiw,  and  as  these  are  different 
from  those  of  a  marine  steam  engine,  the  structure  and  appearance  of  a 
marine  Diesel  engine  are  quite  diverging  from  that  of  an  ordinary  ma- 
rine engine. 

The  Burmeister  &  Wain  Diesel  engines  follow  closely  the  de- 
sign of  their  steam  marine  engines.  This  particularly  applies  to  crank- 
shafts, main  bearings,  connecting  rods,  crossheads  and  guide  shoes. 

The  air  compressor,  by  which  the  air  for  the  fuel  injection  is  com- 
pressed up  to  a  pressure  of  60  atmospheres,  forms  a  most  important  part 
of  a  Diesel  engine.  For  this  purpose  the  type  used  is  of  their  own  de- 
sign, combined  with  the  engine. 

The  engine  is  direct  reversible  and  may  be  built  in  capacities  ranging 
from  200  to  8,000  H.P. 

In  large  types  of  ships  the  installation  is  of  the  twin-screw  system. 
The  two  engines  work  independently.  A  Diesel  ship  of  large  capacity  is 
usually  equipped  with  double  bottom  tanks,  to  have  sufficient  fuel  oil  to 
carry  it  along  for  31,000  miles,  while  the  steamer's  bunker  of  ordinary 
size  can  only  carry  enough  bunker  coal  or  oil  to  carry  it  along  for  an 
average  of  4,800  miles. 

Engines  formerly  used,  built  by  the  Burmeister  &  Wain  Company, 
were  of  the  two-cycle  system,  after  experimenting  with  the  four-cycle 
type,  the  company  succeeded  in  developing  a  four-cycle  engine,  which, 
on  the  same  revolution,  accomplished  the  same  effective  horsepower, 
had  the  same  length,  the  same  breadth,  but  smaller  height  and  weighed 
\y2  tons  less  than  the  two-cycle  of  a  corresponding  horsepower.  The 
total  weight  of  the  engine  in  question,  was  9  tons;  that  of  the  two- 
cycle  10y2  tons.  Moreover,  the  'consumption  of  fuel  oil  in  the  four- 
cycle engine  was  17  per  cemt  less.  Seven  of  'these  engines  have  been 
supplied  to  the  Danish  Navy. 

These  engines  develop  450  E.H.P.  at  500  revolutions  per  minute, 
and  owing  to  their  lighter  weight  and  elegant  construction  they  are 
especially  suitable  for  fast  running  motor  boats  and  yachts. 

The  engine  can  be  made  to  other  dimensions  if  required. 

Of  similar  special  engines  we  mention  a  600  E.H.P.  direct  re- 
versible marine  engine  of  280  revolutions  per  minute  built  for  the 
Societe  Anonyme  John  Cockerill,  Seraing,  Belgium,  for  river  service 
on  the  Upper  Kongo.  This  engine  is  a  type  somewhat  heavier  than 
that  aforementioned,  but  considering  the  small  draft  of  these  vessels 
and  the  consequential  small  diameter  of  the  propellers  they  are  naturally 
rather  fast  running. 


288 


DESCRIPTION  OF  DIESEL  ENGINES 


A  new  designed  type  of  engine  with  an  extra  long  stroke  and  having 
a  corresponding  low  number  of  revolutions  especially  suitable  for  single- 
screw  cargo  ships,  are  now  building.  These  engines  are  intended  for 
slow  going  cargo  ships  and  can,  owing  to  the  low  number  of  revolutions, 
be  fitted  with  large  propellers,  thereby  giving  the  vessel  a  particularly 
good  speed  in  bad  weather,  as  well  as  a  great  maneuvering  capacity; 
likewise  a  good  control  of  the  vessel  is  obtained,  which  is  important  when 
sailing  in  marrow  waters  or  maneuvering  in  or  out  of  port. 

Owing  to  their  low  number  of  revolutions  these  engines  are  of  course, 
a  little  more  expensive  to  build  per  H.P.  They  present  on  the  other  hand, 
such  advantages  that  will  quickly  pay  to  u&e  this  somewhat  more  costly 
engine  for  the  purpose  mentioned. 

The  company  has  adopted  a  standard  size  varying  from  300  to  550  H.P. 
They  are  particularly  well  suited  for  replacing  smaller  steam  plants  of 
old  vessels. 

This  smaller  type  are  direct  reversible.  The  reversing  gear  is  based 
on  special  patents  and  is  of  a  different  design  from  that  adapted  for  the 
cross-head  main  engines,  previously  described,  being  specially  suitable 
for  the  smaller  trunk  engines. 

The  smaller,  reversible  type  of  engines  are  always  of  the  6  cylinder 
construction;  this  number  of  cylinders  gives  the  engine  perfect  balance 
so  necessary  in  marine  work  in  particular.  These  engines  are  particu- 
larly suitable  fosf  installation  in  the  stern  of  the  vessel,  thus  obtaining 
the  advantage  of  a  clear  and  unobstructed  hold. 

The  engines  can  be  used  for  single-screw  as  well  as  for  twin-screw 
vessels. 

With  this  new  design  of  marine  Diesel  engines  there  can  under  all 
circumstances  be  attained  an  excellent  propulsion,  but  it  is  also  neces- 
sary to  build  a  special  type,  as  the  marine  Diesel  engines  designed  for 
twin-screw  vessels  will  not  yield  good  results  in  a  single  screw  vessel, 
which  is  quite  analogous  with  experience  gained  with  steamers. 


STANDARD    MARINE    DIESEL    ENGINES   FOR   SINGLE-SCREW   SHIPS 
(Burmeister  &  Wain  Types) 

Number  of 

Type  Cylinders 

for  Engine 


6  x  125 

6 

6  x  150 

6 

6  x  200 

6 

6  x  250 

6 

6  x  275 

6 

6  x  300 

6 

6  x  400  . 

6 

Corresponding 

Revolutions 

I.  H.  P. 

I.  H.  P. 

Per  Min. 

Normal 

for  Steamers 

84 

750 

680 

84 

950 

850 

82 

1150 

1030 

77 

1350 

1210 

75 

1600 

1400 

72 

1900 

1650 

70 

2300 

2000 

Long  Stroke  Cross  Head  Engines  for  Ocean  Going   Single-Screw  Cargo 
Ships  Adapted  to  a  Speed  of  9  to  12  Knots. 


DESCRIPTION  OF  DIESEL  ENGINES  289 


THE  WINTON   MARINE  DIESEL  ENGINE 

The  principal  features  of  the  Winton  Diesels  are:  The  use  of  an 
enclosed  crankcase,  trunk  pistons  instead  of  the  usual  cross-head  arrange- 
ment, and  crankshaft  bolted  up  to  its  bearings,  which  are  mounted  in  the 
upper  half  of  the  crankcase. 

The  engines,  which  are  of  the  four-cycle  construction,  are  'produced 
in  the  following  three  sizes: 

Six  cylinder,  11x14  inches,  known  as  Model  W35; 
Six  cylinder,  13x18  inches,  known  ia-s  Model  W24A; 
Eight  cylinder,  13x18  inches,  known  as  Model  W40. 

Air  Compressor:  The  fuel  is  forced  into  the  cylinder,  against  the 
compression,  by  a  pressure  averaging  about  850  to  900  pounds  per  square 
inch.  The  compressor  furnishing  the  air  is  located  on  the  forward  end 
of  the  engine.  It  is  of  the  three  istage  construction.  The  compressor 
piston  is  of  the  trunk  type  and  is  operated  by  a  connecting  rod,  which 
is  a  duplicate  of  the  connecting  rod  in  the  power  cylinders  and  a  single- 
throw,  counter-weighted  crankshaft  which  is  bolted  to  the  main  shaft, 
the  throw  being  somewhat  less  than  that  of  the  power  shaft.  Following 
each  stage  of  compression  the  air  is  water-cooled,  so  that  on  delivery  it  is 
at  normal  temperature. 

The  capacity  of  the  air  compressor  is  considerably  in  excess  of  that 
required  for  the  injection  of  the  fuel  and  provides  for  the  initial  charging 
and  maintenance  of  pressure  in  the  storage  tanks,  or  air  bottles,  which 
are  used  for  starting  the  engine. 

There  are  two  .sets  of  these  air  bottles,  one  carrying  the  air  at  about 
600  pounds  pressure  per  square  inch,  which  is  admitted  to  the  cylinders 
in  turn,  to  force  the  pistons  down,  starting  the  engine  rotating.  The 
second  set  of  air  bottles  carries  air  at  1,000  to  1,200  pounds  per  square 
inch.  This  is  used  to  inject  the  fuel  into  the  cylinders.  As  soon  as  fuel 
is  injected,  combustion  takes  place,  performing  the  cycle  of  operation. 

Injection  Operation:  The  valve  timing  conforms  to  costumary  prac- 
tice. The  governor  is  of  the  fly-<ball  type,  and  acts  upon  the  fuel  cut-off 
valve  which  meters  out  the  exact  amount  of  fuel  to  the  fuel  pump  that 
is  required  by  the  load  the  engine  is  carrying. 

Ait  the  time  the  injection  valve  is  opened,  the  amount  of  fuel  that 
has  been  delivered  by  the  fuel  pump  is  blasted  into  the  cylinder  by  the 
high  pressure  air. 

Valve  Arrangements:  The  cam  shaft  is  supported  in  a  long,  box- 
shaped  casting,  open  at  the  top,  which  in  turn  is  supported  on  brackets 
from  cylinders.  This  trough  is  partly  filled  with  oil,  insuring  ample  lubri- 
cation to  the  cams.  Driving  gears  and  cam  shaft  bearings  are  fed  directly 
with  oil  under  pressure  from  pump. 


290 


DESCRIPTION  OF  DIESEL  ENGINES 


|s 

1.4 


Si 


e  ^ 


DESCRIPTION  OF  DIESEL  ENGINES 


291 


The  cam  shaft  is  driven  by  bevel  gears  from  a  vertical  shaft  near 
the  center  of  the  engine,  which  in  turn  is  driven  from  a  lay  shaft  and  a 
train  of  spur  gears  at  front  end. 

The  oam  shaft  is  provided  with  two  complete  sets  of  cams,  for  for- 
ward and  reverse  motion.  Shifting  the  .shaft  endways  by  means  of  a 
hand  wheel  and  suitable  mechanism,  brings  either  /set  of  cams  into  oper- 
ation. The  shifit  from  full  speed  ahead  to  full  speed  stern  is  frequently 
accomplished  in  5  to  6  seconds.  Considering  the  weights  of  parts  which 
must  be  brought  to  resit  and  started  in  motion  in  the  opposite  direction, 
this  is  an  exceptional  performance. 

Each  pair  of  inlett  and  exhaust  valves  is  operated  from  tthe  cam  shaft 
by  a  single  rocker  arm,  the  valves  being  connected 'by  T-head  slide  on 
which  the  end  of  the  rocker  rests.  'Slide  is  carried  in  contact  with  the 
rocker  at  all  times  by  a  coil  spring  in  center  of  its  hollow  stem.  Each 
end  of  the  slide  carries  an  adjusting  screw  and  lock-nut,  'by  which  the 
clearance  between  the  ends  of  the  valve  stem  and  slide  can  be  adjusted. 
This  clearance  is  0.015  inches  for  both  main  inlet  and  exhaust  valves. 
This  pair  of  valves  are  used  instead  of  single  large  valves,  because  small 
valves  are  much  less  apt  to  warp. 

The  fuel  injection  valve  is  located  in  the  center  of  head  and  is  also 
operated  by  a  rocker  from  the  cam  shaft.  The  adjusting  screw  for  this 
valve  is  set  to  leave  0.010  in.  clearance  when  the  Valve  is  closed.  All 
these  clearances  are  for  a  cold  engine,  and  will  be  somewhat  more  as  the 
engine  warms  up. 


OVERALL   DIMENSIONS  AND  WEIGHTS  OF  WINTON    DIESELS 


Model 

Weight          Length         Width           Height            base 

Ibs.              ft.     in.          ft. 

in.          ft.     in.          ft.     in. 

52 

11,000            90             3 

8             5       2V6  '       1       2  VA 

53 

16,000           10       44         3 

/  o                           /  4 

8             5       2  1/6         1       21/4 

54 

22,000           13       4l/2         3 

\j                          u              *i  /Q                  j-              u  74 

8         5     2y8       i     214 

58 

30,000           13       9%         5 

1             66             2.4 

W35 

44,000           18       2             5 

1             66             24 

W24A 

66,000           24       1             5 

103/         7       03/         2       9  1/ 

W40 

90  000           28     10             5 

"/4                          /4                          74 

1034       7     034       2     914 

Model 

Bore         Stroke          Power 

No.   Cylinders 

Inches      Inches 

52 

7V2             11              50  H.P. 

3  Cylinders  —  Reverse  Gear 

53 

7%             11              75  H.P. 

4  Cylinders  —  Reverse  Gear 

54 

7V2             11             115  H.P. 

6  Cylinders  —  Reverse  Gear 

58 

11                 14             150  H.P. 

4  Cylinders  —  Reverse  Gear 

Wg5 

11                 14             225  H.P. 

6  Cylinders  —  Reverse  Gear 

W24A 

12i&             18             300  H.P. 

6  Cylinders  —  Reverse  Gear 

W40 

1211             18             450  H.P. 

8  Cylinders  —  Reverse  Gear 

292  DESCRIPTION  OF  DIESEL  ENGINES 


NOBEL  DIESEL  MARINE  ENGINES 

In  following  de-tail  information  of  the  Nobel  Diesel  of  the  latest  de- 
sign, outstanding  feats  and  features  may  be  summed  up  as  follows: 

Rating,  Speed  and  Weight:  With  a  raited  capacity  of  1,600  brake 
horsepower  yor  2,000  indicated  horsepower  at  a  speed  of  106  revolutions 
per  minute,  the  engine  weighs,  including  a  13-ton  flywheel,  scavenging 
pumps,  air  compressors,  etc.,  but  170  tons,  or  236  Ibs,  per  B.H.P. 

Overall  Dimensions:  The  total  length  of  the  engine  is  7.8  meters  or 
25  ft.  7  in. ;  its  height  above  the  center  of  the  shaft  to  the  top  of  the  fuel 
valve  is  5.9  m.,  or  19  ft.  4  in. 

Fuel  Consumption:  At  full  load  the  fuel  consumption  of  the  engine 
is  0.395  Ib.  of  oil  per  (B.H.P.  hour  with  a,  heatiing  value  of  9,960  calories 
per  kg.,  or  17,900  B.T.U.  per  Ib.  Comparing  well  in  this  figure  with  the 
highest  record  'established  by  four-cycle  engines.  At  lighter  loads  the 
fuel  consumption  of  this  engine  is  considerably  less  than  that  of  any 
four-cycle  engine  of  equal  proportion. 

Mean  Indicated  Pressure:  At  the  rated  load,  the  M.I.P.  is  6.48  at 
92  Ibs. 

Mechanical  Efficiency:  At  full  load  the  mechanical  efficiency  is  81 
per  cent.  At  10  per  cent  overload  the  mechanical  efficiency  is  82.3  per 
cent. 

Overload  Capacity:  The  heaviest  overload  so  far  carried  is  22  per 
cent,  the  engine  developing  1,958  B.H.P.  at  108  R.P.M.  continuously  during 
a  period  of  three-fourths  of  an  hour,  without  any  serious  complication. 

General  Information:  The  engine  follows  the  two-cycle  principle. 
The  arrangement  of  its  scavenging  ports  in  the  cylinder  walls  and  its 
scavenging  pumps,  are  valv«  controlled,  with  the  exception  of  the  scav- 
enging air.  Inasmuch  as  the  scavenging  ports  possess  a  greater  height 
than  the  exhaust  ports,  a  greater  efficiency  in  supercharging  is  accom- 
plished. 

The  engine  is  of  the  open  "A"  frame  type,  bolted  to  the  bedplate 
as  well  as  to  the  cylinders.  Commendable  features  are  the  one-sided 
cross-head  -slippers,  the  links  and  rocker  arms  which  serve  to  actuate  the 
scavenging  pumps,  the  air  compressors  and  circulating  pumps,  built  to 
follow  the  general  prevailing  marine  practice. 

The  engine  has  four  working  cylinders,  each  resting  upon  the  two 
cast  iron  columns  composing  one  "A"  frame.  Rocker  arms,  connected  to 
the  cross-heads,  drivei  in  the  following  order,  the  combined  low  and  high 
pressure  stages  of  the  injection  air  compressor,  the  two  scavenging  pumps 
and  the  intermediate  stage  of  the  air  compressor.  All  this  machinery 
is  supported  by  brackets  fastened  to  the  bedplate  directly  opposite  to 
the  frames.  This  arrangement  has  the  advantage  by  which  it  utilizes 
the  available  space  in  the  best  manner,  particulalry  in  the  longitudinal 
direction  of  the  ship,  which  is  of  the  greatest  value,  assisting  in  estab- 


DESCRIPTION  OF  DIESEL  ENGINES  293 

lishing  accessibility  and  a  more  satisfactory  arrangement  in  pump  opera- 
tion. 

The  scavenging  air  is  pumped  into  the  hollow  frames  of  the  engine 
which  serve  as  air  ireceiver.  The  frames  are  connected  to  each  other  by 
means  of  distance  pieces  of  sufficiently  laBge  cross  section. 

The  operating  platform  is  arranged  near  the  top  of  the  engine,  where 
all;  the  vital  parts  for  operating  and  maneuvering  are  within  easy  reach 
of  the  operator.  If  it  should  be  preferred  to  have  the  operators  stand  on 
the  main  floor,  no  doubt  this  could  be  accomplished,  but  would  require 
some  additional  and  more  or  less  complicated  gearing. 

Cylinders  and  Port  Arrangement:  The  inner  liner  of  'the  cylinder  is 
made  of  close-grained  cast  iron  and  with  a  mild  shrink-fit  inserted  into 
the  outer  jacket.  The  parts  of  the  cylinder  surrounding  the  exhaust  ports 
are  provided  with  drilled  vertical  holes  in  order  to  secure  a  most  effective 
water  cooling.  The  exhaust  pipe,  connecting  all  four  cylinders,  is  also 
water  cooled.  An  extension  to  the  cylinder  oni  the  opposite  side  carries 
the  piston  valve  which  prevents  the  exhaust  gases  entering  here  and 
which,  controls  the  scavenging  air.  This  valve  isi  actuated  by  a  push-rod 
from  a  cam  on  the  layshaft  above.  The  scavenging  air  enters  from  below, 
leaving  the  hollow  frame  casting  which  has  previously  been  mentioned, 
serves  as  air  receiver. 

In  the  center  of  the  cylinder  head  is  the  fuel  valve  of  standard  de- 
sign, on  one  side  the  air^starting  valve  is  arranged;  on  the  other  side  is 
the  compression  relief  valve,  Which  is  combined  with  the  safety-valve, 
and  which  relieves  the  compression  in  order  to  facilitate  starting.  The 
air  which  during  starting  is  compressed  in  the  working  cylinders,  is  not 
permitted  to  go  to  waste,  but  escapes  into  the  air  receiver  and  inter- 
mingles with  the  scavenging  air. 

It  may  'be  mentioned  here  that  this  arrangement  in  adding  to  the 
scavenging  air,  is  very  valuable,  especially  since  it  takes  place  in  the 
beginning  of  the  operation,  before  the  scavenging  pumps  have  been  able 
to  fill  the  receiver  with  air  of  the  required  pressure.  It  eliminates  any 
trouble  which  may  occur  in  starting  the  engine. 

The  pressure  of  the  scavenging  air  is  kept  exceedingly  low;  at  full 
load  and  full  speed  it  only  amounts  to  1.6  Ibs.  per  square  inch.  All  these 
factors  contribute  to  reduce  the  work  expended  for  the  scavenging  pumps 
to  a  minimum.  At  full  load  and  normal  speed  it  amounts  to  about  3.5 
per  cent  of  the  total  indicated  horsepower  of  the  engine.  The  advantage 
of  low  pressure,  in  dispensing  with  artificial  cooling,  is  easily  under- 
stood. By  accurate  test  it  was  found  that  the  rise  of  temperature  at  full 
load  only  amounted  to  10-12°  C.  or  18-21°  Fahr. 

The  compression  in  the  cylinder  is  at  slow  speed  38.5  Ibs.,  and  the 
pressure  in  the  scavenging  air  receiver  but  0.21  Ib.  The  injection  air 
pressure  at  this  speed  is  430  1'bs.,  in  fact,  only  slightly  higher  than  the 
compression  in  the  cylinder.  It  is  here  mentioned  that  even  at  normal 
speed  the  compression  is  430  Ibs.,  the  scavenging  pressure  1.6  Ibs.,  and 
the  injection  air  pressure  860  Ibs. 


294  DESCRIPTION  OF  DIESEL  ENGINES 

Operating  and  Reversing  Features:  In  maneuvering  we  may  sum- 
mlarize  the  operating  performance  in  following:  In  bringing  the  eccentric 
shafts  in  neutral  position,  the  fuel  valves  are  put  out  of  motion  and  the 
puel  pumps  are  cut  out,  thereby  the  engine  is  brought  to  a  standstill 
after  a  few  revolutions. 

By  turning  the  reversing  lever,  by  means  of  a  gear  segment  and  a 
rack,  the  camshifting  rod  is  moved,  which  in  its  turn  brings  the  cams 
for  the  reverse  rotation  into  their  power  position.  'Simultaneously,  by 
a  system  of  levers  and  rods,  the  'scavenging  air  controlling  valves  are 
brought  into  their  correct  position  for  the  reverse,  whereupon  the  start- 
ing can  be  effected  in  the  usual  way. 

The  various  levers  are  mechanically  interlocked,  so  that  it  is  im- 
possible to  move  the  reversing  lever  and  shifting  rod,  unless  both  eccen- 
tric turning  levers  are  in  their  neutral  position  and  on  the  other  hand 
none  of  these  levers  can  be  moved,  unless  the  reversing  levers  and  with 
it  the  other  parts,  cams  and  valves  are  in  their  proper  position  either 
for  forward  or  astern  running. 

In  starting  the  engine  a  careful  investigation  should  be  made  that 
all  piping  is  properly  filled  with  fuel  and  the  required  amount  of  air  is 
in  the  compressed  air  tank. 

The  rollers  of  the  starting  valve  and  of  the  relief  valve  are  brought 
into  contact  with  their  corresponding  cams  and  at  least  one  of  the 
starting  valves  will  immediately  open  and  will  admit  air  to  its  cylinder. 
The  air  pressure  sets  the  engine  into  motion,  and  after  one  or  two  revo- 
lutions, as  soon  as  the  engine  has  received  sufficient  momentum,  the 
engineer  throws  the  turning  levers  into  the  normal  running  position, 
which  sets  the  starting  and  the  relief  valve  idle  and  puts  the  fuel  valve 
into  service. 

Main  Dimensions 
Working  Cylinders:  •    , 

Diameter  26.574  in. 

Stroke : 36.200  in. 

Scavenging  Air  Pumps,  Double  Acting: 

Diameter 36^4  in- 

Stroke  .. 26^  in. 

Diameter  of  Plunger  Guide : 7%  in. 

Air  Compressor: 

Diameter  for  the  three  stages, 22^  in.,    9y8  in.,    415e  in. 

Stroke  for  all  three  stages 22^  in. 

Water  Pumps,  Single  Acting: 

2  Pumps  for  cooling  cylinders,  etc. 

Diameter  x  Stroke 5  in.  x  14  in. 

2  Pumps  for  general  service,  bilge,  etc. 

Diameter  x  Stroke 5  in.  x  14  in. 

Circulating  Pump  for  pistons 

Diameter  x  Stroke 5  in.  x  6%  in. 


DESCRIPTION  OP  DIESEL  ENGINES  295 

Crank  Pin: 

Diameter  x  Length 15%  in.  x  19  in. 

Main  Bearings: 

Diameter  x  Length  of  Journal 15%  in.  x  27^4  in- 


THE  VICKERS  DIESEL  ENGINE 

There  is  no  doubt  that  in  the  past  many  failures  in  Marine  Diesel 
Engines  have  been  due  to  the  lack  of  sea-going  marine  knowledge  among 
those  responsible  for  the  design  and  manufacture  of  the  machinery.  Dif- 
ficulties which  had  been  overcome  in  the  best  reciprocating  steam  engine 
were  often  unwittingly  resurrected  in  the  early  Diesel  design,  and  new 
mechanical  troubles  were  invited.  In  surmounting  these  the  engine-room 
staffs  were  compelled  to  spend  much  of  the  time  they  would  otherwise 
have  devoted  to  mastering  the  purely  Diesel  features  of  the  engines. 

Heavy  oil  engine  work  is  not  a  new  line  with  Vickers.  They,  prac- 
tically alone  of  British  makers,  have  evolved  an  engine  of  their  own, 
which  since  1909  has  been  accepted  as  the  British  Standard  for  their  sub- 
marine service,  for  which  it  was  designed.  In  the  few  cases  in  which 
foreign  designs  have  been  tried  against  it  in  similar  circumstances,  Vick- 
ers engines  have  proven  their  equal. 

The  engine  referred  to  is  of  the  high  duty  express  type,  of  which 
over  380,000  B.H.P.  are  made  or  in  hand,  and  the  experience  gained  with 
this  class  of  engine  renders  it  a  comparatively  easy  task  to  develop  the 
slow  running  type  of  marine  engine  required  for  mercantile  work.  In 
addition,  they  have  made  two  pairs  of  750  B.H.P.  engines  running  at  150 
R.P.M.  which  have  given  satisfactory  service. 

A  brief  summary  ofi  the  Vickers  engine  now  specially  designed  for 
mercantile  use  is  given  in  the  following  pages: 

The  engine  is  of  the  four-stroke  cycle,  this  type  having  been  adopted 
by  the  Vickers  Company.  The  first  point  of  departure  from  all  other 
Diesels  is  in  the  adoption  of  a  fuel  injection  system  in  which  the  air 
compressor  is  entirely  done  away  with.  For  some  years  now  this  system 
has  been  adopted  by  Vickers  on  all  their  engines  to  the  entire  exclusion 
of  the  air  injection  system,  notwithstanding  that  Vickers  are  manufac- 
turers of  air  compressors  and  are  therefore  fully  alive  to  the  improve- 
ments in  modern  machinery.  Nevertheless  their  opinion,  which  will 
probably  be  shared  by  most  experienced  seagoing  Diesel  engineers,  is 
that  in  the  compressed  air  system  lies  the  main  source  of  trouble  and 
danger  in  the  modern  marine  Diesel  engine.  For  this  reason,  although 
saving  of  weight  and  space  is  not  so  important  in  merchant  ships  as  in 
submarines,  for  instance,  they  recommend  solid  injection  for  mercantile 
work.  Another  reason  is  that  the  system  is  very  foolproof  and  lends  it- 
self to  successful  operation  by  a  comparatively  unskilled  personnel  and 
in  case  of  necessity  can  be  kept  running  when  an  air  injection  engine, 


296  DESCRIPTION  OF  DIESEL  ENGINES 

owing  to  variations  of  adjustment,  would  be  dangerous  to  start.  There 
is  nothing  mysterious  in  the  system,  in  fact,  its  simplicity  is  a  revelation 
to  many.  A  proof  of  its  efficiency  is  found  in  the  fact  that  the  Vickers 
air  spraying  Diesels  supplied  prior  to  the  development  of  the  Vickers 
injection  -system  were  subsequently  converted  at  the  owners  request. 
Contrary  to  uninformed  comment  from  some  quarters,  this  system  gives 
full  consumption  results  better  than  many  spraying  systems,  consump- 
tions per  hour  down  to  0.378  Ibs.  per  B.H.'P.  having  been  obtained  in  the 
official  tests  of  Vickers  engines.  This  would  correspond  to  about  0.28  Ib. 
per  indicated  horsepower  in  an  ordinary  air  injection  engine. 

The  disposition  and  number  of  the  auxiliary  pumps  on  the  main 
engine  depends  on  the  arrangement  of  the  engine  room.  The  standard 
design  permits  of  iswaybeamis  being  fitted  to  the  two  end  cross-heads 
from  w.hich  the  required  pumps  may  be  driven. 


DESCRIPTION  OF  DIESEL  ENGINES 


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298  DESCRIPTION  OP  DIESEL  ENGINES 

Details  of  "Vickers"  Solid   Injection   Engines 

One  of  the  problems  in  connection  with  the  development  of  the 
marine  oil  engine  in  motorships  which  ia  attracting  the  greatest  atten- 
tion among  engineers  concerned  with  this  branch  of  engineering  is  the 
efficacy  of  the  solid  injection  system,  as  compared  with  the  ordinary  blast 
or  pressure  injection  principle  which  has  hitherto  been  mainly  adopted 
for  motors  for  mercantile  service.  For  this  reason,  if  for  no  other,  the 
latest  types  of  Vickers  engine  deserves  (mention. 

As  perhaps  the  fuel  system  is  of  the  greatest  interest  from  the  en- 
gineering standpoint,  we  will  first  deal  with  the  arrangement  ado.pted. 
which  is  novel  in  many  respects.  The  principle  lies  in  forcing  fuel  oil  at 
about  4,000  Ibs.  per  square  inch  direct  into  the  cylinder  through  a  special 
type  of  valve  in  the  cylinder  cover — a  system  which  has  been  used  by 
Vickers  for  many  years  past  on  all  their  'submarine,  monitor  and  tanker 
engines,  and  has  proved  its  reliability  under  arduous  conditions. 

The  fuel  is  supplied  under  this  pressure  by  means  of  a  small  battery 
of  four  pumps  of  the  ordinary  plunger  type.  The  plungeirs  are  driven 
from  four  eccentrics  operated  from  the  horizontal  shaft,  which  itself  is 
driven  by  spur  gearing  from  the  crankshaft.  The  fuel  from  these  pumps 
is  taken  through  a  small  box  to  the  main  pipe  line  and  thence  a  pipe  is 
tapped  off  to  each  cylinder  in  connection  with  a  small  shut-off  cock  in 
each  case.  It  would  be  difficult  to  devise  any  simpler  arrangement,  and 
the  choice  of  four  pumips  is  merely  a  matter  of  convenience,  having  no 
direct  relationship  to  the  number  of  cylinders.  There  is  a  hand  pump 
close  to  the  main  fuel  pumps  for  ipriming  the  pipes,  with  a  delivery  to 
the  .fuel  box.  The  control  of  pressure  of  oil  fuel  is  effected  through  a 
small  lever  acting  on  the  suction  valve  of  the  pumps  in  the  usual  manner 
through  a  spindle.  This  pressure,  wMch  can  easily  be  .maintained  at 
practically  4,000  Ibs.  per  square  inch,  can  also  be  varied  within  smaller 
limits  by  another  small  'hand  wheel.  Its  effect  is  the  same  as  that  of 
the  lever. 

We  will  now  deal  with  the  valve  gear  and  method  of  control,  which, 
owing  to  the  singular  method  employed  should  be  carefully  studied. 

The  camshaft  ibeing  driven  by  gearing  by  means  of  a  sloping  shaft, 
which  is  itself  driven  from  the  crankshaft  through  bevel  gearing,  sup- 
plied by  forced  lubrication  from  the  main  bearing  oil  lubricating  system 
at  a  pressure  of  about  20  Ibs.  per  square  inch.  On  this  camshaft  are  itwo 
side-fcy-side  cams  for  the  operating  of  each  valve — exhaust,  fuel,  inlet, 
and  starting.  These  cams  are  enclosed.  No  mechanically  operated  start- 
ing valve  is  needed  in  the  cylinder  cover,  where  there  is  only  a  non- 
return valve — a  simplification  with  some  advantages.  The  exhaust  valve, 
inlet  valve,  and  fuel  valve  are  operated  by  levers;  the  levers  being 
mounted  on  the  maneuvering  shaft  and  actuated  from  the  cams  on  the 
camshaft. 

The  method  of  reversing  can  now  easily  be  followed,  since  it  is  clear 
that  (the  following  operations  have  to  be  carried  out: 


DESCRIPTION  OF  DIESEL  ENGINES  299 

1.  The  valve  levers  have  to  be  lifted  off  the  cams  on  the  camshaft. 

2.  The  camshaft  has  to  be  moved  fore  and  aft  to  bring  the  astern 
cams  underneath  the  rollers  of  the  valve  levers,  after  which  the  levers 
must  be  dropped  down  again  on  the  cams. 

3.  Compressed  air  has  to  be  admitted  to  all  six  cylinders,  then  two 
have  to  be  placed  on  fuel  and  four  on  air;  next,  two  on  air  and  four  on 
fuel,  and  finally  all  on  fuel. 

If  the  engine  is  running  when  the  order  is  given  to  stop,  'the  hand 
wheel  is  turned  to  stop  position  as  indicated  on  the  dial.  This  causes 
a  partial  rotation  of  the  spindle,  which  raises  or  lowers  the  rods.  These 
are  attached  to  sleeves,  on  which  the  levers  operating  the  fuel  valves 
are  eccentrically  mounted.  The  other  end  of  the  lever  on  the  fuel  valve 
cam  is,  therefore,  raised  from  the  cam  by  this  operation  and  is  only 
brought  down  on  to  the  cam  at  the  right  moment  by  the  movement  of 
the  starting  wheel.  In  other  words,  when  the  engine  is  in  the  stop  .posi- 
tion the  fuel  valves  and  starting  air  valves  are  automatically  out  of 
operation  until  the  hand  wheel  is  moved. 

Assuming  the  engine  is  stopped  after  having  been  running  ahead, 
and  the  order  is  received  to  go  astern,  the  reversing  lever  is  moved  from 
the  back  position  to  the  front.  This  putsi  compressed  air  on  the  Servo 
motor,  which  by  means  of  a  rack  motion,  first  partially  rotates  the  hori- 
zontal shaft — which  lifts  the  exhaust  and  inlet  valve  levers  off  their  cams 
through  the  link,  then  causes  the  lever  to  move  fore  and  aft,  giving  the 
corresponding  motion  to  the  camshaft,  after  which,  by  the  continued 
rotation  of  the  shaft  and  the  movement  of  the  link,  the  valve  levers  are 
once  more  brought  down  on  to  the  cams.  Only  when  this  complete 
movement  has  been  effected  is  it  possible  to  move  the  starting  wheel. 

Immediately  the  cams  are  in  the  astern  iposition  this  starting  wheel 
is  rotated  by  hand  until  ithe  indicator  on  the  dial  shows  that  air  being 
supplied  to  all  six  cylinders  through  the  distributing  valves  behind  this 
wheel.  There  are  three  of  these  valves  with  three  main  pipes,  each 
leading  to  two  of  'the  starting  valves.  The  engine  then  starts  uip  on 
air,  after  which,  with  an  almost  imperceptible  pause,  the  starting  wheel 
is  turned  to  the  next  position  indicated  on  the  dial,  namely  two  cylinders 
on  fuel  and  four  on  air.  This  is  accomplished  by  the  rotation  of  the 
spindle  as  previously  mentioned,  allowing  two  of  the  fuel  valve  levers  to 
come  down  on  their  cams.  Further  rotation  of  the  starting  wheel  <cuts 
off  the  air  supply  and  allows  four  of  the  six  cylinders,  and  finally  all  of 
them  to  operate  on  fuel. 

It  should  be  mentioned  that  the  valve  levers  are  lifted  off  their  cams 
by  <tlhe  movement  of  the  maneuvering  shaft,  owing  to  the  fact  that  these 
levers  are  mounted  eccentrically  upon  the  shaft.  The  reason  that  the 
fuel  valve  levers  are  brought  down  on  to  their  'cams  in  pairs  as  described 
is  that  there  are  cams  on  the  shaft  which  lift  ithe  levers  at  the  time  re- 
quired for  putting  into  action  the  respective  valves,  according  to  the 
position  of  the  starting  wheels. 


300  DESCRIPTION  OF  DIESEL  ENGINES 

It  may  be  noticed  that  there  is  a  hand  pump,  operated  by  a  lever,  in 
case  it  is  desired  to  carry  out  the  reversal  by  hand  instead  of  by  com- 
pressed air,  in  which  case  the  small  lever  is  pulled  over  to  the  forward 
or  hand  position. 

We  are  not  debating  in  this  article  the  advisability  of  either  four- 
stroke  cycle  or  two-stroke  cycle  as  found  preferable  by  the  Bush-Sulzer 
Engineers,  Nordberg's,  etc.,  but  it  is  but  fair  to  add  here  that  the  Vickers 
Ltd.,  claims  a  matterof-fact  figure  on  economy  in  fuel  consumption  in 
their  adopted  four-stroke  cycle  engines,  which  by  official  test  of  British 
officials  is  reduced  to  0.378  Ib.  per  B.H.P.,  corresponding  to  0.278  Ib.  per 
I.H.P.,  in  an  ordinary  air  injection  engine.  TMs  they  claim  is  principally 
accounted  for  through  their  method  of  injection  system. 


SIZES,  WEIGHTS  AND  DIMENSIONS  OF  "WESTERN"  DIESEL 

ENGINES 

"Western"  Diesel  Engines  now  are  manufactured  in  standard  size  of 
25  B.H.P.  per  working  cylinder,  in  multiples  up  to  six  cylinders.  With 
following  data  obtainable,  sizes,  weights  and  dimensions  are  as  follows: 

No.                                                                        Shipping  Shipping 

Cylinders         Brake  H.P.           R.  P.  M.              Weight  Weight 

Domestic  Export 

1  25                        325                 10,000  1-bs.  12,000  Ibs. 

2  50                        325                14,000  Ibs.  15,750  Ibs. 

3  75                        325                 17,500  Ibs.  19,250  Ibs. 

4  100  325  20,000  Ibs.          24,000  Ibs. 
6                      150                        325  28,000  Ibs.          32,500  Ibs. 

'Shipping   weights-  given  are   for   standard   commercial   engines. 

In  the  "Western"  Diesel  engine  the  atomized  fuel  is  injected  into 
the  highly  compressed  air  in  the  cylinder,  igniting  on  its  own  compres- 
sion similar  to  all  Diesel  process. 

In  the  open  type  nozzle  fuel  injection  the  fuel  first  enters  in  a  pass- 
age-way which  opens  into  the  main  combustion  chamber  of  the  engine, 
and,  immediately  the  oil  has  been  deposited  in  this  passage-way,  a  blast 
of  highly  compressed  air  from  an  outside  source  drives  it  through  small 
openings  with  such  force  that  it  enters  the  main  combustion  chamber 
in  such  a  highly  atomized  state  that  complete  combustion  takes  place  as 
soon  as  it  mixes  wifch  the  compressed  air  contained  therein. 


DESCRIPTION  OF  DIESEL  ENGINEiS  301 

DESCRIPTION    OF   THE    600   B.H.P.    MARINE    WERKSPOOR    ENGINES 

INSTALLED    IN    THE    TWIN-SCREW    MOTOR    TANKER 

"CHARLIE  WATSON"    (STANDARD  OIL) 

Total  Brake  Horsepower  1200. 

The  engines  are  of  the  four-cycle,  single-acting  marine  crosshead 
type,  and  each  develops  800  indicated  horsepower,  or  600  brake  horse- 
power at  165  revolutions  per  minute.  The  cylinder  blocks,  connected  by 
an  intermediate  piece  over  the  maneuvering  station,  carry  each,  a  set 
of  three  cylinders.  The  cylinder  block  at  the  same  time  forms  a  water 
jacket  around  the  cylinders,  and  is  <sup>ported  by  cast-iron  frames  on  the 
crosshead  guide  block  and  by  the  opposite  guide  block  columns  which 
are  bolted  to  same.  The  cylinder  block  and  the  .guide  block  are  again 
supported  by  lower  columns,  which  rest  on  and  are  bolted  to  the  bed- 
plate. Heavy  steel  tie  rods  run  from  the  top  of  the  cylinder  block  through 
the  bottom  of  the  bedplate,  with  nuts  on  each  end. 

With  this  design,  each  set  of  three  cylinders  has  one  -combined  cross- 
head  guide  block,  which  is  supported  by  lower  column's.  After  lifting 
four  tie-rods  on  one  side  of  the  engine,  these  small  columns  are  taken 
out  and  the  crankshaft  can  then  be  removed. 

The  built-up  crankshaft  is  10%  inches  in  diameter.  The  main  bear- 
ings are  of  the  square  box  type,  the  square  boxes  carrying  the  bottom 
brasses,  which  are  made  iso  that  they  can  be  rotated  and  come  clear. 

The  piston  rods  pass  through  stuffing  boxes  of  the  drip  pans  which 
collect  carbon  and  used  oil  from  the  cylinders  and  prevent  same  leaking 
into  the  lower  oil-tight  part  of  the  engine,  which  is  provided  with  forced 
lubrication.  The  lubricating  oil  enters  through  the  binder  of  each  main 
bearing  and  is  forced  through  the  crankshaft  to  the  crankpin  and  through 
the  hollow  connecting  rod  to  the  crosshead.  A  drip  pan  bolted  under 
and  to  the  bedplate  collects  the  return  oil,  which  is  again  pumped  by  an 
electrically  driven  pumip  through  strainers  back  to  the  main  bearings. 

The  cylinder  and  cylinderhead  are  cast  in  one  piece.  It  provides  an 
efficient  water-cooling  around  the  cylinder  top,  and  furthermore  increases 
the  cooling  water  circulation  between  the  valve  housings. 

In  casting  the  cylinder  and  head  in  one  piece,  allowance  has  been 
made  for  easy  examination  or  removal  of  the  piston  from  below. 

This  is  done  by  placing  the  crank  on  the  bottom  center  and  dropping 
the  cylinder  extension  or  skirt  onto  the  drip  pan,  which  then  exposes  the 
full  length  and  top  of  the  piston  and  allows  for  easy  removal  of  the 
rings.  By  the  loosening  of  four  bolts  on  the  end  of  piston  rod,  the  piston 
can  be  lifted  down. 

The  piston  is  air  cooled  and  provided  with  eight  rings. 

The  intake  and  exhaust  valves  are  of  cast  iron,  with  steel  steins. 

The  fuel  needle  can  be  easily  removed  and  ground  in  place  while  the 
engine  is  running. 


302 


DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES  303 

This  also  applies  to  the  safety  valve,  which  at  the  same  time  is  used 
as  relief  valve,  its  spring  being  relieved  while  the  engine  is  reversed. 

All  valve  springs  are  outside  the  valve  cage,  in  order  to  keep  them 
cool  and  free  for  inspection. 

The  engine  is  fitted  with  the  new  Werkspoor  reversing  gear.  The 
rockers  are  mounted  on  skew  eccentrics,  keyed  to  the  reversing  shaft, 
which,  when  turned  over  180  degrees,  lift  and  transfer  the  rocker  rollers 
from  the  ahead  to  the  astern  cams,  and  vice  versa. 

The  camshaft  is  actuated  'by  four  connecting  rods  from  the  half- 
time  shaft  below,  which  is  driven  by  a  spur  gear  from  the  main  crank- 
shaft. The  gear  wheel  on  the  lower-half-time  shaft  contains  the  governor, 
which  acts  on  the  fuel  pump  when  the  engine  speeds  up  over  165  revo- 
lutions per  minute. 

The  lower  half-time  shaft  carries  two  eccentrics,  each  operating  a 
set  of  three  plungers  of  the  fuel  pump,  which  is  bolted  on  the  bedplate 
at  the  maneuvering  stand.  The  fuel  pump  has  to  take  care  of  an  equal 
fuel  distribution  to  all  fuel  needles,  and  therefore  has  a  separate  plunger 
for  each  cylinder. 

Each  plunger  delivers  fuel  only  when  its  suction  valve  is  closed.  The 
suction  valves  are  lifted  by  two  rockers  which  are  actuated  by  the 
crossheads  of  the  pump  and  which  pivot  "around  an  accentric.  The  pivot- 
ing points  of  these  rockers  are  lowered  or  raised  by  turning  the  eccentric 
through  either  the  hand  levers  on  the  maneuvering  stand  or  through  the 
action  of  the  governor.  When  lowered,  the  suction  valves  close  earlier 
and  the  pump  delivers  more  fuel;  when  raised,  the  suction  valves  close 
later  and  the  pump  delivers  less  fuel.  Three  adjusting  screws  in  each  of 
said  rockers,  one  under  each  suction  valve,  allow  an  accurate  adjustment 
of  the  amount  of  fuel  to  each  cylinder.  A  pyrometer  in  each  exhaust 
enables  the  engineer  to  check  the  amount  of  fuel  fed  to  each  cylinder  in 
comparison  with  the  others. 

The  fuel  from  the  fuel  pump  passes  through  a  manifold  which  is 
placed  on  top  of  the  frame  between  the  two  cylinder  blocks.  This  mani- 
fold contains  a  second  delivery  valve  for  each  fuel  plunger,  and  is  called 
the  cut-out  block,  as  it  carries  two  cut-out  valves  for  the  injection  air, 
one  to  each  set  of  three  cylinders.  These  two  valves  are  operated  by 
the  (hand  levers  from  the  maneuvering  station. 

There  are  also  six  spindle  valves  for  the  purpose  of  cutting  out,  'by 
hand,  the  injection  air  to  each  cylinder  separately  if  ever  found  neces- 
sary. 

The  air  compressor  is  provided  with  crossheads  and  is  driven  by  a 
crankshaft  which  is  ibolted  to  the  forward  end  of  the  main  crankshaft. 

The  compressor  piston  rods  run  through  stuffing  tboxes  of  a  dia- 
phragm drip-pan.  The  cylinder  liners  and  the  three  corresponding  coolers 
are  set  in  one  oast-iron  block,  which  forms  at  the  same  time  a  water 
jacket.  This  arrangement  allows  the  pistons  and  coolers  to  be  easily 
removed  from  the  top. 


304  DESCRIPTION  OP  DIESEL  ENGINES 

Besides  delivering  air  to  the  injection  air-bottle,  the  air  compressor 
charges  the  starting  air  bottles  from  the  intermediate  pressure  cooler. 
The  air  inlet  to  the  low  pressure  cylinder  can  be  regulated  by  hand.  All 
valves  are  of  the  plain  disc  type. 

The  engine  is  reversed  from  the  maneuvering  station  by  an  air  ram, 
cushioned  by  an  oil  cylinder  and  connected  to  a  vertical  shaft  fitted 
with  a  gear  rack  w.hich  rotates  the  camshaft  180  degrees  to  the  ahead 
or  astern  position. 

At  the  maneuvering  station  are  two  hand  levers,  each  of  which  con- 
trols at  the  same  time  the  starting  air  and  fuel  supply  to  the  engine. 

On  the  right  of  the  maneuvering  station  are  the  forced  feed  lubri- 
cators for  the  (main-  cylinders  and  those  of  the  air  compressor,  while 
directly  on  the  left  are  pressure  gauges  for  lubricating  oil,  low  pressure 
air,  intermediate  pressure  air,  starting  air,  and  injection  air.  On  the 
bedplate  at  the  maneuvering  station  are  mounted  the  high  pressure  fuel 
pump  and  a  fuel  hand  pump,  all  placed  at  ia  central  point  from  which 
the  engineer  can  watch  the  action  of  the  engines. 

While  the  Werkspoor  engine  has  'been  patterned  after  their  original 
design,  nevertheless  for  use  in  the  United  States  considerable  depar- 
tures from  European  mechanical  arrangements  are  considered  advisable 
by  American  manufacturers.  .As  is  universal  with  four-cycle  marine 
engines,  the  valves  are  actuated  by  cams  on  the  horizontal  camshaft. 

Inasmuch  as  the  Werkspoor  engines  are  adhering  to  cross-head  con- 
struction, thence  the  piston  rod  is  short,  the  cylinders  are  supported  by 
vertical  steel  cylindrical  columns.  The  inclined  cast-iron  columns  being 
mainly  for  the  purpose  of  taking  the  thrust  due  to  the  connecting  rod. 

Following  the  usual  procedure  of  four-cycle  engines,  the  arrange- 
ments of  the  valves  are  in  similarity  to  the  Burmeister  &  Wain,  Mclntosh 
&  Seymour,  etc.,  there  being  four  in  the  cover  of  each  cylinder.  The 
fuel  inlet  valve,  being  located  in  the  center  is  notable  for  its  difference 
from  valves  of  this  kind  of  other  types  of  machinery  in  Diesel  construc- 
tion. Where  springs  are  used  to  hold  the  same  in  its  seat,  a  lever  attach- 
ment serves  to  hold  the  same  securely  in  its  place,  the  valve  in  this  case 
being  held  down  by  a  spring  on  one  side  exerting  its  pressure  at  one 
end  and  acting  against  the  force  of  the  cam,  the  lever  assisting  in  its 
functioning.  A  valve  of  this  kind  may  easily  be  replaced  and  at  all 
times  can  be  quickly  examined. 

The  reversing  method  of  the  Werkspoor  is  exceedingly  simple.  Sim- 
ilar to  the  four-cycle  large  types  of  engines  its  procedure  is  carried  out. 
The  maneuvering  levers  are  raised  clear  of  the  cams,  the  consequential 
shifting  of  the  cam  sihafts  back  and  forward  accomplishing  the  reversing, 
which  is  followed  after  this  with  bringing  the  levers  back  in  desired 
position. 


DESCRIPTION  OF  DIESEL  ENGINES 


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DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES 
NATIONAL  TRANSIT  DIESEL  ENGINES 


307 


The  National  Transit  engines  have  novel  departures  from  the  types 
of  older  construction.  Features,  such  as  advanced  pump  equipments, 
modern  valve  arrangement  of  exclusive  National  Transit  design,  latest 
compressor  construction,  etc.,  are  well  deserving  of  highest  comment. 

As  will  be  observed  by  the  accompanying  illustrations  of  the  National 
Transit  types  of  twin  engines,  as  well  as  double  engines,  the  machines 
are  suitable  as  factors  where  the  requirements  call  for  stationary  power 
producers.  The  company  has  made  a  study  of  Diesel  engine  design  cor- 
responding with  modern  features  of  exclusive  American  principle.  Satis- 


Plan  View  showing  detail  arrangement  of  J5Vz   X  24  Twin  Oil  Engine. 


308 


DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES  309 

factory  results  dealing  with  economy  establishments  have  been  noted, 
principally  by  adhering  to  established  uniform  construction  of  original 
designs  with  added  late  Improvements. 

The  illustration  of  the  National  Transit  Twin  Oil  Engine,  of  size 
15^x24  inches,  shows  the  constructive  advantages  of  this  particular 
classification.  Both  cylinders  and  the  bedplate  are  one  casting,  a  signifi- 
cant feature  eliminating  undue  stresses  and  assuring  rigid  construction. 
Each  cylinder  is  provided  with  a  liner. 

Three  main  frame  bearings  and  an  outboard  bearing  are  shown  sup- 
porting the  flywheel  and  the  crankshaft.  Sufficient  space  is  left  between 
the  flywheel  and  main  frame  to  allow  the  installation  of  a  belt  pulley. 
The  lay  shaft  is  driven  from  the  crankshaft  by  means  of  out  spiral  gears. 
It  serves  to  drive  the  valve  gear,  governor,  sprayer,  air  starter  and  lubri- 
cating and  fuel  oil  pumps.  In  this  respect  it  should  be  noted,  that  the 
general  arrangement  allows  accessibility  to  all  parts  for  inspection  or 
adjustment  when  the  requirement  calls  for  the  same. 

As  will  be  observed  from  the  illustration  that  the  main  fuel  pumps 
and  governor  are  mounted  together  in  a  single  assembly  on  the  right 
hand  side  of  the  main  frame.  Each  fuel  pump  is  driven  by  an  eccentric 
on  the  lay  shaft,  and  each  side  of  the  engine  has  a  separate  fuel  pump. 
The  pump  plungers  are  of  the  differential  type,  the  upper  or  large  part 
beins  hollow  and  having  a  cut-off  valve  seated  at  its  upper  end.  Each 
cut-off  valve  is  under  direct  control  of  a  Jahn's  .governor.  Each  plunger 
has  a  full  positive  stroke  with  each  revolution  of  the  lay  shaft.  Govern- 
ing  is  effected  by  allowing  the  cut-off  valve  to  seat  at  a  pre-determined 
point  in  the  upper-stroke  of  the  plunger,  thus  delivering  to  the  sprayer 
a  quantity  of  oil  correctly  proportioned  to  the  load  which  the  engine  is 
carrying.  The  governor,  as  previously  stated,  is  driven  by  spiral  gears 
from  the  lay  shaft. 

Spraying  is  effected  by  the  open  nozzle  type,  and  located  in  (the  ex- 
treme out  end.  of  the  combustion  chambers.  Fuel  oil  from  each  fuel 
pump  is  deposited  in  the  open  channel  of  each  sprayer  body.  As  soon 
as  the  valve  controlling  the  compressed  injection  air  opens,  this  oil  is 
injected  into  the  combustion  chamber  thoroughly  atomized,  and  is  ignited 
by  the  process  of  heat  temperature. 

The  problem  of  suitable  material  for  cylinder  heads  has  been  con- 
sidered on  this  engine.  All  cylinder  heads  are  made  from  specially 
selected  cast  iron  with  large  cored  water  passages.  The  large  water 
jacket  arrangement  in  no  way  endangers  the  thermal  efficiency  of  the 
engine,  but  rather  acts  in  harmony  with  temperature  normalizing  neces- 
sary in  reliable  operation  of  internal  combustion  machinery. 

The  intake  and  exhaust  valves  operate  in  cages,  either  of  which  is 
easily  withdrawn  by  removing  two  nuts.  The  valves  are  operated  by 
cams  through  rocker  arms.  The  cams  are  mounted  on  a  shaft,  in  front 
of  and  below  the  cylinder  head.  This  -shaft  is  driven  from  the  lay  shaft 
by  bevel  gears. 


310 


DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES  311 

A  single  two-stage  compressor  for  spraying  the  liquid  fuel  into  the 
power  cylinders  is  bolted  to  the  engine.  This  compressor  is  driven  by  a 
connecting  rod  from  the  main  crankshaft  of  the  engine.  The  piston  is 
of  the  differential  type.  The  cylinders  and  also  the  valves  are  amply 
water-jacketed.  An  inter-receiver,  which  is  virtually  an  inter-cooler,  is 
provided  between  the  high  and  low  stage  air  compressor  cylinders.  The 
high  stage  air  is  discharged  at  about  1000  Ibs.  pressure  into  a  seamless 
steel  discharge  pipe  which  acts  as  a  receiver  and  which  conveys  it  to 
the  sprayer. 


THE   NORTH    BRITISH    DIESEL   ENGINE 

This  type  of  engine  is  of  the  four-cycle  construction.  Its  eight  cyl- 
inders cast  en  bloc  are  of  26 1/3  inches  diameter,  with  47  inches  piston 
stroke. 

The  shaft  horsepower  of  the  engine  is  rated  at  2,000  B.H.P.,  or  250 
B.H.P.  per  cylinder,  and  the  piston  speed  at  96  R.P.M.  is  817  feet  per 
minute. 

The  engine  develops  normally  at  96  R.P.M.,  2,380  indicated  horse- 
power, or  292  I.H.P.  per  cylinder,  equivalent  to  steam  driven  machinery 
where  twin  engine  motor  power  is  installed,  to  4,500  I.H.P. 

In  connection  with  this  it  should  be  noted  that  the  engine  is  rated 
at  the  very  moderate  mean-effective  pressure  (on  B.H.P.  basis)  of  ap» 
proximately  80  Ibs.  per  square  inch. 

In  considering  the  foregoing  figures  it  should  also  be  remembered 
that  the  fuel  injection  air  compressors  are  not  driven  from  the  main 
engines,  but  are  in  twin  sets  in  duplicate  driven  by  auxiliary  Diesel 
engines  of  the  same  type  as  the  main  engines,  but  with  trunk  pistons 
and  run  at  250  R.P.M.,  whereas  the  main  engines  are  of  the  single  acting 
crossjhead  type. 

All  pistons  on  main  engines  are  internally  water  cooled,  a  telescopic 
pipe  and  jet  system  being  employed. 

Its  reversing  is  accomplished  by  a  system  of  camshaft  and  eccentric, 
assisted  by  levers  causing  the  camshaft  to  fall  and  raise  in  its  respective 
operating  position. 


THE  STEINBECKER   DIESEL   ENGINE 

(Note. — This  engine  is  a  late  development  of  exclusive  German  de- 
sign. Its  remarkable  adaptability  to  utilize  Tar-Oil  for  fuel  purposes,  with 
its  consequential  special  design  to  accomplish  the  burning  of  the  same, 
is  herewith  set  forth.) 

The  engine  of  the  future  probably  must  be  able  to  operate  continu- 
ously on  coal  tar-oils  as  well  as  asphaltic  oils.  While  the  problems  to 


312  DESCRIPTION  OF  DIESEL  ENGINES 

be  solved  in  the  design,  manufacture  and  operation  of  such  engines  are 
now  greater  than  those  connected  with  engines  utilizing  lighter  fuel  oils, 
experience  will  solve  them;  the  world's  supply  of  the  more  volatile  oil 
fuels  is  not  inexhaustible  and  sooner  or  later  the  heavier  fuels  must  be 
quite  commonly  used. 

One  of  the  German  firms  devoting  much  attention  to  the  develop- 
ment of  engines  burning  very  heavy  oils,  such  as  tar-oils,  is  Priedrich 
Krupp,  Germaniawerft,  Kiel-Garden,  Germany,  who  in  addition  to  building 
their  own  cross-head  and  trunk-piston  types  of  Diesel  engines,  have  a 
license  for  the  manufacture  of  the  Steinbecker  engine.  The  first  100 
H.P.  two-cylinder  engine  has  been  developed  under  the  personal  super- 
vision of  the  inventor,  Mr.  Steinbecker. 

The  Steinbecker  engine  has  no  compressor  and  might  be  called  a 
combination  of  the  surface-ignition  and  full-Diesel  principle. 

Principle  of  Operation:  The  principle  of  operation  is  as  follows: 
Towards  the  end  of  the  compression  stroke  the  fuel  pump  forces  a  small 
quantity  of  oil  through  the  horizontal-channel  into  the  vertical-channel, 
the  top  end  of  which  is  fitted  with  a  bulb  with,  a  number  of  spray  holes, 
the  bottom  end  being  open  to  the  cylinder.  As  the  air  rushes  from  the 
cylinder  into  the  bulb  it  atomizes  the  oil  in  the  same  manner  as  water  is 
atomized  in  a  flower-spray  as  used  by  florists,  and  the  mixture  of  air 
and  oil  is  carried  into  the  bulb.  When  the  piston  reaches  the  top  of  the 
stroke  this  mixture  of  oil  and  air  is  ignited  by  the  heat  produced  by  com- 
pression, resulting  in  great  increase  in  pressure  and  a  back-rush  of  the 
burnt  ,gases  which  carry  into  the  cylinder  the  oil  fuel  which  the  pump 
has  meanwhile  pumped  into  the  vertical  channel.  In  the  cylinder  the 
mixture  burns  and  expands  in  the  same  manner  as  in  other  Diesel  engines. 

Special  Features:  It  will  thus  be  seen  that  this  Steinbecker  engine 
is  a  Diesel  engine  without  a  compressor,  which  atomizes  the  fuel-oil  by 
blowing  it  with  great  velocity  into  the  combustion  chamber  by  means 
of  gases  which  are  formed  by  exploding  a  small  amount  of  fuel-oil  in  a 
hot  retort. 

This  engine  is  claimed  to  >be  less  complicated  and  therefore  cheaper 
to  build  than  the  usual  full^iesel  type;  the  fuel-needle-valve,  injection 
air-bottle,  air  compressor,  and  high-pressure  air  piping  are  eliminated. 
For  starting  the  engine  from  cold  a  small  auxiliary  sprayer  is  provided, 
which  may  be  put  out  of  action  when  the  engine  is  running. 


DESCRIPTION  OF  DIESEL  ENGINES  313 

THE   WORTHINGTON   SOLID   INJECTION    DIESEL    ENGINE 
An  Advanced  Method,  Burning  Fuel  Oil  in  Small  and  Medium  Sizes. 

The  Worthington  Solid  Injection  Engine  has  a  new  form  of  combus- 
tion chamber,  inherently  controlling  the  combustion  time  and  rate,  inde- 
pendent of  time  of  pump  injection.  This  new  Worthington  solid  injection 
Diesel  engine  has  no  operative  limitations  of  size,  is  capable  of  burning 
all  fuel  oils  of  the  air  injection  engines,  and  -lias  all  of  the  elements  of 
simplicity  and  reliability  so  necessary  in  practical  operation. 

Worthington  Divided  Combustion  Chamber,  Injection  Chamber,  Ejec- 
tion Orifice  and  Cylinder:  The  special  fuel  burning1  and  combustion  con- 
trol feature,  is  a  divided  combustion  chamber,  wholly  water  jacketed  as 
in  Standard  Diesel  engines,  but  differing  from  them  in  having  two  parts 
connected  by  a  fuel  ejection  orifice.  One  part  of  the  combustion  cham- 
ber, that  between  the  cylinder  head  and  the  top  of  the  piston,  holds  about 
three  quarters  of  the  air.  The  other  part,  which  is  the  injection  chamber, 
holds  about  one-quarter  of  the  air  at  the  end  of  compression.  Combus- 
tion takes  place  in  two  stages,  and  starts  with  injection,  the  first  oil 
entering  being  ignited  by  the  hot  air. 

Injection  Chamber — Combustion  Limited:  Fuel  is  injected  by  the 
pump  as  a  spray  directly  into  the  injection  chamber,  where  the  full 
charge  of  oil  could  not  meet  more  than  one-quarter  of  the  air,  even  if  all 
the  air  in  the  injection  chamber  came  into  contact  with  all  the  oil.  Partly 
by  design  of  the  spray  nozzle  to  give  a  suitable  form  to  the  spray,  and 
partly  by  the  shape  of  the  injection  chamber,  the  oil  is  prevented  from 
coming  into  contact  with  more  than  a  part  of  the  injection  chamber  air, 
so  that  even  less  than  one-quarter  of  the  total  is  active  in  burning  oil 
during  injection.  As  a  consequence  the  pressure  cannot  rise  very  much 
during  injection,  no  matter  how  fast  the  Injection  nor  how  much  too 
early  the  pump  may  be  timed,  within,  reasonable  limits.  If  only  half  of 
the  injection  chamber  air  is  active,  then  not  more  than  one-eighth  of  the 
oil  could  burn  during1  injection;  if  onenquarter  of  the  air  came  in  contact 
with  the  oil,  not  more  than  onensixteenth  of  the  oil  charge  could  burn 
and  the  pressure  could  rise  only  one-isixteenth  as  much  as  if  the  oil  were 
suddenly  sprayed  into  the  whole  air  charge  of  an  air  injection  Diesel 
engine  combustion  chamber. 

Main  Cylinder  Combustion  Automatically  Graduated  by  Pressures  on 
Ejection  Orifices:  After  injection  of  the  oil  into  the  injection  chamber 
with  limited  air  contact,  and  partial  or  pre-combustion,  the  unburned  oil 
has  been  gasified  by  the  partial  combustion,  and  this  oil  gas  is  suspended 
out  of  contact  with  the  cold  walls  in  the  bottom  of  the  injection  chamber, 
and  close  to  the  ejection  orifice.  It  is  ready  for  ejection  into  the  main 
air  charge  in  the  cylinder.  The  gasified  unburned  oil,  which  includes  the 
bulk  of  the  charge  delivered  by*  the  pump  will  be  forcibly  ejected  into 
the  cylinder  through  the  ejection  orifice  at  the  right  time  by  the  outward 
movement  of  the  piston,  which  causes  the  pressure  to  fall  in  the  cylinder, 
aided  by  the  slight  rise  of  pressure  in  the  injection  chamber,  due  to  the 


314 


DESCRIPTION  OF  DIESEL  ENGINES 


limited  pre-combustkm.  As  it  emerges  from  the  injection  chamber,  the 
hot  gasified  oil,  accompanied  by  some  unused  air  from  the  injection  cham- 
ber and  followed  by  the  rest  of  it,  burns  in  the  main  air  charge  in  the 
cylinder  as  fast  as  it  flows.  By  the  high  flow  velocity  of  the  gases  pass- 
ing through  the  orifice,  a  violent  mixing  action  is  set  up  by  the  jet  enter- 
ing the  cylinder,  that  contributes  to  good  combustion. 


Transverse  Sectional  Assembly,  Outside  Air  Passages,  Worthington  Diesel 
Engine,  Two-Cycle,  Solid  Injection. 


Two-Cycle  Cross-head  Construction:  The  air  charging  of  the  cylinder 
is  done  by  the  two-cycle  method  as  the  best  arrangement  for  the  ranges 
of  sizes  adopted.  In  this  respect  the  standard  practice  in  surface  ignition 
engines  has  been  followed,  but  in  the  details  of  carrying  out  this  plan 
the  trunk  piston  with  crankcase  scavenging  chamber  has  not  been  ac- 


DESCRIPTION  OF  DIESEL  ENGINES  315 

cepted.  Instead,  the  cross-head  construction  of  the  large  Diesel  motor- 
ship  engine  has  been  adopted,  with  the  crank  end  of  the  cylinder  used  as 
a  scavenging  pump.  This  arrangement  keeps  all]  scavenging  air  out  of 
the  crankcase,  permitting  the  use  of  circulating  forced  feed  lubrication 
of  all  bearings  without  loss  of  oil,  and  by  the  stuffing  box  separating 
cylinder  from  crankcase,  also  preventing  contamination  of  main  lubricat- 
ing oil  by  foul  cylinder  oil. 

Difficulty  in  Design  of  Solid  Injection  Diesel  Engine:  Nothing  would 
seem  to  be  easier  than  to  attach  the  solid  injection  pump  and  spray  nozzle 
of  the  surface  ignition  engine  to  a  Diesel  engine,  to  make  a  solid  injec- 
tion Diesel  engine.  This  has  been  tried  'by  many  and!  each  learned  the 
same  lesson.  The  combination  is  hopelessly  bad,  worse  by  far  than  either 
of  the  originals.  The  combustion  is  bad  with  heavy  smoke  and  much 
internal  carbon,  and  fuel  consumption  is  high.  Explosive  shocks  and 
thumps,  or  loss  of  power,  or  both,  are  also  present  if,  the  combination 
works  at  all,  with  (possible  loss  of  control  by  the  governor,  and  in  most 
cases  imperativeness  of  the  injection  pumps.  Shocks  and  detonations 
are  due  to  difficulty  of  controlling  the  timing  of  injection  and  rate  of 
combustion,  which  if  too  early  or  too  fast,  always  produces  this  effect, 
and  doubly  so  if  both  too  early  and  too  fast.  Delaying  injection  will 
eliminate  detonations  and  explosive  shocks,  but  then  combustion  will 
surely  be  too  slow  and  last  too  long,  resulting  in  excessive  high  fuel 
consumption.  Smoke  and  internal  carbon  are  due  to  improper  sprays,  or 
rather  too  improper  relation  of  the  form  and  shape  of  spray  to  the  form 
of  combustion  chamber,  aggravated  'by  the  use  of  heavier  fuel  oil  than 
before.  Pump  and  governor  control  difficulties  are  due  primarily  to  in- 
crease of  delivery  pressure,  but  they  are  increased  by  the  substitution 
of  Diesel  grades  of  fuel  oil  for  the  lighter,  more  fluid  grades  for  which 
the  mechanism  of  the  surface  ignition  engine  was  designed. 

Development  of  Solid  Injection  Principle  of  Worthington  System: 
Having  discovered  that  the  fuel  system  of  pump,  governor  control  and 
spray  valve  of  the  solid  injection  surface  ignition  engine,  applied  to  a 
Diesel  engine  will  not  work,  the  most  obvious  step  is  to  change  the  former 
to  fit  the  latter.  This  will  attain  at  least  one  ideal,  the  elimination  of 
surface  ignition  hot  metal  and!  adherence  to  the  completely  water  jack- 
eted combustion  chamber  of  the  Diesel  engine,  with  high  enough  com- 
pression to  ignite  fuel  by  the  hot  air  alone. 

Another  ideal  of  greater  importance,  but  also  of  greater  difficulty  in 
attainment,  is  the  prevention  of  explosive  shocks  and  detonations,  .by 
arranging  for  the  non-explosive  combustion  of  the  Diesel  engine  in  such 
a  way  as  to  make  explosive  combustion  impossible,  and  not  merely  a 
matter  of  -  pump  injection  timing,  which  if  deranged  defeats  the  aim. 
Complete  commercial  success  in  the  solution  of  this  problem  was  never 
attained  until  the  numerous  experiences  through  the, effort  of  the  Worth- 
ington Company  have  added  towards  the  solution. 

Early  Solid  Injection  Diesel  Engines — Their  Limitations:  These  two 
early  solid  injection  Diesel  engines  are  different  from  each  other,  and 


316  DESCRIPTION  OF  DIESEL  ENGINES 

each  has  such  a  limited  scope  and  characteristics  as  to  justify  the  con- 
clusions that  the  Worthington  solution  of  the  problem,  the  latest  de- 
velopment in  the  solid  injection  oil  engines,  is  a  real  contribution  to  the 
small  engine  field  that  has  so  long  needed  the  solution  of  this  problem. 

One  of  these  early  solid  injection  Diesel  engines  is  the  result  of  re- 
design of  sipray  nozzle,  fuel  oil  pump,  and  controls,  for  direct  solid  injec- 
tion into  the  ordinary  Diesel  engine  combustion  chamber  without  any 
change  in  the  latter  as  to  shape  or  compression  carried.  Fairly  good 
combustion  of  fuel  oils  has  been  secured  in  engines  of  considerable  size, 
but  not  in  small  ones  commercially,  and  not  without  extreme  sensitive- 
ness as  to  adjustment,  which  must  be  almost  of  micrometer  exactness 
to  avoid  explosive  detonation  shocks  or  smoky  combustion,  or  both.  In 
itself  this  system  is  so  far  no  more  than  a  demonstration  that  a  Diesel 
engine  can  <be  operated  with  solid  injection  spraying,  instead  of  air 
spraying,  and  with  about  the  same  efficiency.  It  also  proves,  however, 
that  there  is  a  need  in  such  cases  for  some  special  reliable  means  of  in- 
suring proper  accuracy  of  adjustment  of  fuel  feed  and  combustion  rate, 
or  preferaibly,  of  securing  automatically  the  proper  control  without  accu- 
rate adjustment. 

Small  Solid  Injection  Diesel  Engines  Without  Pump  Injection,  Fuel 
Feed  Cups:  The  second  of  the  early  solid  injection  Diesel  engines  pre- 
ceding the  final  solution,  is  an  invention  which  again  uses  the  standard 
Diesel  combustion  chamber,  but  with  a  new  method  of  fuel  feed,  without 
a  timed  injection  pump.  This  method  of  fuel  injection  successfully  pre- 
vents the  development  of  explosive  shocks  toy  automatic  means  operated 
by  cylinder  pressures  that  make  it  impossible  for  the  fuel  to  enter  too 
soon  or  too  fast.  In  these  engines  .fuel  feed  is  a  two  stage  operation. 
During  the  first  stage  fuel  flows  by  gravity  from  a  constant  level  chamber 
similar  to  that  forming  part  of  any  carburetor,  past  a  metering  needle 
valve  into  a  cup  projecting  into  the  combustion  chamber,  and  communi- 
cation with  it  by  very  small  holes  in  the  side  of  the  cup  near  the  bottom. 
The  cup  receives  its  oil  charge  before  compression  starts  and  the  fuel  is 
prevented  from  flowing  into  the  cylinder  by  the  smallness  of  the  holes 
at  first,  and  later  during  compression,  the  oil  is  held  in  the  cup  by  the 
compressing  air  that  flows  through  the  hole  from  the  cylinder  into  the 
cup.  No  oil  can  flow  out  of  the  cup  until  the  cup  pressure  is  higher  than 
the  cylinder  .pressure,  or  what  is  the  same  thing,  until  the  cylinder  pres- 
sure falls  below  the  cup  pressure,  which  will  surely  happen  during  the 
first  part  of  the  expansion  stroke.  At.  this  time  the  oil  will  escape  into 
the  cylinder,  accompanied  and  followed  by  air  from  the  €up  which  sprays 
the  oil  into  the  main  air  that  'has  ibeen  compressed  to  be  hot  enough  to 
ignite  the  fuel.  This  fuel  feed  cup  type  of  engine,  which  is  a  commer- 
cial success,  again  demonstrate  the  practicability  of  operating  a  solid 
injection  Diesel  engine,  and  the  importance  in  so  doing  of  preventing  too 
early  or  too  fast  an  injection  of  oil  by  simple  means  that  does  not  require 
sensitive  adjustment. 

This  means  of  fuel  feed  control  is  effective  in  very  small  engines,  of 
sizes  beginning  with  one  horsepower,  competing  directly  with  carburetor 


DESCRIPTION  OF  DIESEL  ENGINES  317 

gasolene-kerosene  engines,  at  but  little  increase  in  cost  and  at  least  equal 
simplicity  and  reliability,  but  it  has  not  been  successful  in  the  intermed- 
iate sizes  up  to  the  smaller  air  injection  Diesel  engines,  the  range  of 
sizes  mainly  occupied  by  the  surface  ignition  engines.  While  it  may  .suc- 
cessfully burn  fuel  oil,  it  is  ordinarily  operated  on  kerosene  to  avoid 
difficulties  of  flow  with  various  oils.  It  contributes  something  toward  the 
solution  of  this  problem,  but  is,  not  itself  a  -solution  any  more  than  the 
former  step  noted.  Its  size  limitation  is  due  to  the  necessity  for  small 
holes  in  the  cup  to  prevent  premature  escape  of  fuel  into  the  cylinder, 
and  the  difficulty  in  larger  sizes  of  dividing  the  oil  'between  many  holes, 
each  of  which  is  small  enough.  Its  greatest  lesson  is  the  proof  that 
automatic  proper  control  of  time  and  rate  of  combustion  is  possible,  if 
special  means  be  devised  for  the  purpose,  even  though  the  means  used  is 
not  of  universal  application,  and  that  the  combustion  rate  control  means 
may  be  wholly  or  partly  independent  of  pump  or  spray  valve  timing. 


FUEL   PUMP  AND   CONTROL    END  OF  WORTHINGTON 
TWO-CYCLE  ENGINE 

Speed  regulation  is  obtained  by  opening  a  by-pass  and  not  by  varia- 
tion of  the  length  of  the  fuel  pump  stroke. 

The  amount  of  fuel  supplied  to  the  cylinder  depends  on  the  time  of 
opening  of,  the  by-pass  valve.  This  in  turn  depends  on  the  angular  posi- 
tion of  the  eccentric  shaft,  which  is  controlled  by  the  governor. 

The  governor,  which  is.  located  on  the  end  of  the  engine  crankshaft, 
is  connected  to  the  eccentric  shaft  by  suitable  links.  Any  increase  In 
the  engine  speed  from  normal  will  cause  the  governor  to  turn  eccentric 
shaft  thru  a  small  angle  which  at  the  same  time  will  lift  end  of  by-pass 
lever.  When  the  fuel  pump  plunger  raises  the)  'by-pass  lever  and  by-pass 
plunger,  by-pass  valve  will  be  opened  earlier.  As  a  result  of  this  earlier 
opening  of  the  by-pass  valve,  more  fuel  is  by-passed  back  to  the  fuel 
supply  reservoir,  thus  reducing  the  amount  supplied  to  the  cylinder  and 
promptly  bringing  the  speed  back  to  normal,  without  changing  the  time 
when  injection  starts. 

Eccentrics  keyed  on  the  engine  crankshaft  drive  the  fuel  pump  plun- 
gers through  the  tappets.  The  upper  ends  of  the  eccentric  straps  are 
provided  with  hardened  steel  contact  rollers  and  are  guided  by  links, 
replacing  the  crosshead  and  guide  construction  previously  used  on  older 
types.  The  pump  plunger  tappets  pass  through  a  partition  which  pre- 
vents fuel  oil  leaking  down  into  the  control  housing  and  mixing  with  the 
lubricating  oil.  All  running  parts  are  splash  lubricated  by  oil  from  end 
main  bearing,  overflowing  back  to  the  crankcase  sump  so  as  to  keep  a 
high  level  in  the  control  housing. 

A  hand  adjusting  screw  at  the  end  of  the  by-pass  lever  makes  it 
easy  to  equalize  the  oil  delivery  from  all  plungers  on  multi-cylinder 
engines. 


318 


DESCRIPTION  OP  DIESEL  ENGINES 
WORTHINGTON  SNOW  OIL  ENGINE 


The  Snow  Oil  Engine  described  in  following  pages,  is  of  'the  repre- 
sentative type  of  late  advanced  development  in  internal  combustion  ma- 
chinery. In  it  is  embodied  the  best  and  latest  American  engineering 
practice,  together  with  such  features  of  European  design  as  have  become 
standard  for  this  class  of  machinery. 

Unlike  the  Marine  Engine,  where  the  vertical  construction  is  uni- 
versally adopted  and  as  a  matter  of  fact  is  advantageous  in  many  re- 
spects, the  stationary  engine  appears  to  be  adhering  to  the  horizontal 
construction. 


^   >-> 

«  *> 

.§  £ 

1! 

*s 


For  stationary  purpose,  by  the  manufacturers  of  oil  engines  follow- 
ing the  horizontal  design,  the  following  advantages  are  claimed  in  the 
horizontal  construction  in  contrast  to  the  vertical  method: 


DESCRIPTION  OF  DIESEL  ENGINES 


319 


(1)  There  is  a  better  distribution  of  stresses  on  the  crank  shaft  and 
main  bearings.  (2)  Better  lubrication  of  piston.  (3)  Easier  cleaning 
and  repair  work,  especially  to  pistons,  which]  can  be  taken  out  without 
removing  the  cylinder-head  or  valve  gear.  (4)  Inspection  is  easier  and 
attendance  more  convenient.  (5)  Less  height  is  required  in  the  engine 
room. 

A  claim  has  been  often  advanced,  that  in  horizontal  engines  there  is 
a  greater  wear  on  the  cylinder  walls,  on  account  of  their  carrying  the 
weight  of  the  piston.  However,  as  vertical  engines  are  almost  entirely 


OJ 

I 


of  the  trunk  piston  type,  the  height  required  making  the  use  of  a  cross- 
head  impracticable.  The  cylinder  walls  are  required  to  take  the  thrust 
due  to  the  angularity  of  the  connecting  rod,  the  magnitude  of  the  thrust 
increasing  with  a  decrease  in  the  connecting  rod  length. 

An  analysis  of  the  varying  forces  throughout  the  cycle  shows  that 
this  thrust  pressure  is  several  times  greater  than  the  pressure,  due  to 


320  DESCRIPTION  OF  DIESEL  ENGINES 

the  weight  of  a  piston  carried  horizontally.  With  usual  design,  increas- 
ing the  connecting  rod  one  crank  length  will  decrease  the  thrust  by  an 
amount  about  equal  to  the  weight  of  one  piston.  From  the  foregoing  it 
is  apparent  that  it  is  of  slight  importance,  whether  the  piston  is  carried 
vertically  or  horizontally. 

The  greatest  advantage  of  the  horizontal  engine  lies  in  its  greater 
accessibility.  This  applies  particularly  to  engines  like  the  Snow  Oil 
engine,  which  are  built  with  cross-head.  In  the  case  of  a  vertical  trunk 
piston  engine  it  is  necessary  to  practically  dismantle  the  engine  in 
order  to  get  at  the  piston  or  wrist  pin  bearing.  This  means  that  the 
valve  gear  and  cylinder  head  must  be  removed,  the  connecting  rod  dis- 
connected at  the  crank  pin  box  and  the  piston  and  connecting  rod  then 
lifted  out  through  the  upper  end  of  *he  cylinder.  Compare  this  with  the 
procedure  in  the  case  of  a  horizontal  engine.  The  sheet  steel  crank 
splasher  is  removed,  the  connecting  rod  disconnected  at  the  wrist  pin 
end,  and  the  piston  then  removed  through  'the  open  end  of  the  cylinder. 
The  actual  required  time  for  removal  of  the  piston  and  cross-head  of 
engine  as  illustrated  in  Figure  2  is  twenty  minutes.  The  piston  and 
crossroad  can  be  replaced  and  the  engine  made  ready  for  operation  in 
thirty  minutes  more,  making  the  total  shut  down  fifty  minutes.  The 
same  procedure  on  a  vertical  engine  requires  an  average  ot  about  ten 
hours. 

The  lubrication  of  the  power  cylinders  in  much  more  easily  and 
effectively  accomplished  on  a  horizontal  engine.  In  a  vertical  engine  it  is 
necessary  to  inject  oil  into  the  piston  at  several  points  in  the  circum- 
ference of  the  cylinder  bore,  while  a  horizontal  cylinder  can  be  thoroughly 
lubricated  by  a  single  feed  on  the  upper  side,  the  oil  being  distributed  by 
gravity.  Further,  in  all  internal  combustion  engines  some  of  the  lubri- 
cating oil  is  carbonized.  In  the  vertical  engine  this  carbon  works  past 
the  piston  rings  and  falls  into  the  crank  pit,  where  it  mixes  with  the 
bearing  oil.  In  an  engine  of  horizontal  construction,  much  of  this  carbon 
is  pushed  into  the  counter  bore  of  the  cylinder,  from  where  it  is  removed 
by  a  drain  valve.  Such  of  the  carbon  as  does  pass  by  the  cross-head  of 
the  piston  is  caught  in  the  frame  and  prevented  from  mixing  with  the 
bearing  oil. 

We  will  give  now  some  of  the  features  adding  to  economy.  The 
high  efficiency  of  the  Diesel  type  of  engine,  unequalled  by  any  other 
method  of  power  production  for  either  marine  or  stationary  purpose,  is 
primarily  due  to  the  high  compression.  It  also  varies  with  the  degree 
of  thoroughness  with  which  the  fuel  and  air  is  mixed,  so  thait  the  economy 
actually  obtained  is  to  a  considerable  extent  dependent  upon  the  design 
of  the  parts  by  which  the  mixing  is  effected. 

Another  feature  of  considerable  importance  and  peculiar  to  the  Diesel 
type,  is  the  slight  variation  in  fuel  economy  through  a  considerable  range 
of  load.  This  feature  is  of  particular  advantage  in  installations  consist- 
ing of  one  unit,  and  which  are  required  to  operate  at  low  load  factors 
for  a  considerable  portion  of  the  time. 


DESCRIPTION  OF  DIESEL  ENGINES 


321 


It  will  be  interesting  here  to  show  established  facts  of  fuel  consump- 
tion for  the  Snow  Oil  Engine: 

0.48  Ibs.  per  B.H.P.  hour  at  full  load. 

0.50  Ibs.  per  B.H.P.  hour  at  three-fourths  load. 

0.57  Ibs.  per  B.H.P.  hour  at  one-half  load. 

The  guarantees  are  based  on  oil  having  a  heat  value  of  18.500 
B.T.U.'s  per  pound.  In  operation  the  fuel  consumption  is  considerably 
below  the  guarantees,  as  shown  in  Figure  3,  which  gives  the  result  of  a 
test  through  wide  range  of  load  under  ordinary  working  conditions.  This 


LBS.   PER  BRAKE  HORSE  POWER  HOUR 


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1 1 

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II 


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F 
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\ 

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i 

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L 

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iu* 

20% 

4 

/ 

30% 

/ 

/ 

40% 

/ 

/ 

50% 

/ 

, 

00% 

70% 

80% 

90% 

100* 

i 

110% 

curve  shows  ithe  fuel  economy  which  can  be  attained  in  actual  service 
and  also  the  very  slight  increase  in  fuel  consumption  for  a  considerable 
decrease  in  load  factor  from  full  load. 

The  construction  of  the  compressor,  as  used  on  the  Snow  Oil  engine, 
is  shown  in  the  longitudinal  sectional  view  of  Figure  4.  This  compressor 
is  a  three-stage  type.  The  cut  shows  the  valves,  suction  and  discharge 


322 


DESCRIPTION  OF  DIESEL  ENGINES 


for  the  three  stages,  both  assembled  and  with  the  guard  and  valve  strips 
removed. 

As  will  be  observed  from  the  sectional  view  of  the  compressor,  that 
it  is  thoroughly  water-jacketed  and  provided  with  inter-coolers  formed 
in  the  jackets  for  low  and  intermediate  stages.  The  after-cooler  for  the 
high  stage  air  is  a  pipe-coil  placed  in  the  water  chamber  adjacent  to  the 
high  pressure  cylinder.  In  addition  the  discharge  valve  for  all  stages  are 
provided  with  a  water  jacket  of  special  design,  which  keeps  the  valve 


parts  at  a  low  temperature,  (preventing  carbonization  of  the  lubricating 
oil,  and  assisting  the  action  of  the  inter-coolers.  The  efficiency  of  these 
cooling  arrangements  is  so  great,  that  the  air  in  the  discharge  pipe  from 
the  high-stage  cylinder  is  cooled  sufficiently  to  allow  the  hand  to  be 
placed  on  the  pipe  without  discomfort  when  the  engine  is  in  full  opera- 
tion. 


DESCRIPTION  OP  DIESEL  ENGINES 


323 


Of  the  different  types  of  spray  valves  used  on  Diesel  machinery,  the 
Snow  Oil  engine  employs  one  of  a  most  .simple  nature.  This  spray  valve 
is  of  the  open  nozzle  tyipe,  the  fuel  being  deposited  in  a  pocket,  which  is 
in  communication  with  the  clearance  space  in  the  cylinder.  When  the 
air  valve  is  opened,  the  oil  is  driven  by  the  spraying  air  through  the 
atomizer  from  which  it  issues  into  the  cylinder  in  a  finely  divided  spray. 


The  open  nozzle  construction  has  the  advantage  that  pure,  clean  air 
only  and  not  a  mixture  of  oil  and  air,  passes  the  spray  valve,  with  the 
result  that  it  is  much  easier  to  maintain  a  perfect  valve  seat  and  ac- 
cordingly to  hold  the  spray  air  pressure  without  annoying  leakage 
through  valve. 


324 


DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OP  DIESEL  ENGINES  325 

The  spray  air  valve  and  the  fuel  oil  check  valve,  which  prevents  the 
oil  charge  from  flowing  back  to  the  pumps,  are  contained  in  a  single 
casing  located  in  the  exact  center  of  the  cylinder  head,  thus  insuring  an 
even  dispersion  of  the  spray  throughout  the  clearance  space  in  the 
cylinder. 

The  spray  valve  and  casing  can  be  taken  out  intact  by  removing  two 
nuts,  or  if  desired,  the  spray  valve  only  can  ibe  removed  for  inspection 
without  disturbing  the  valve  casing. 

As  previously  explained,  the  open  fuel  injection  nozzle  is  the  most 
important  advance  toward  continuity  of  service  and  adaptability  for 
various  oils  that  has  been  made  in  the  Diesel  type  of,  engines. 

It  consists  essentially  of  an  oil  receptacle  with  separate  inlets  for 
the  oil  and,  air  at  one  end,  and  connected  to  the  combustion  chamber  at 
the  other  end  by  a  stationary  atomizing  device.  The  oil  is  pumped  into 
the  receptacle  through  check  valves  during  the  suction  stroke  of  the 
engine,  and  the  injection  air  is  admitted  through  a  separate  mechanically 
operated  timing  valve.  Like  most  modern  engines,  the  Allis-Chalmer 
arrangement  of  injection  is  of  the  open  fuel  injection  nozzle  type. 


Diagram  of  Oil  Pipe  Connection 

There  is  no  valve  after  the  oil  and  air  are  mixed,  thus  avoiding  cut 
valve  seats.  There  are  no  perforated  or  notched  discs  with  restricted 
areas  and  sharp  changes  in  direction  to  clog  with  dirt,  asphalt  or  car- 
bonized oil.  It  does  not  depend  upon  the  water  jackets  to  prevent  car- 
bonizing. 

This  atomizing  is  effected  by  a  simple  device  that  does  not  require  a 
close  relation  between  the  size  of  openings  and  the  amount  of  oil;  so 
that  the  maximum  power  of  the  engine  is  limited  simply  by  the  amount 
of  oxygen  available  for  combustion  and  not  by  the  capacity  of  the  nozzle. 
This  gives  a  remarkable  flexibility  with  swinging  loads. 

The  freedom  from  clogging  permits  the  use  of  the  lowest  grades  of 
fuel  without  the  interruptions  of  service  for  cleaning  or  grinding  the 
valve  so  frequent  with  the  closed  nozzle. 

The  open  nozzle  and  the  mostly  adopted  scavenging  feature  of  the 
horizontal  type  of  stationary  engines,  permits  the  successful  use  of  any 
fuel  oil  that  can  be  pumped,  including  oils  that  require  pre-heating  to 
make  them  flow  readily  through  the  ipiping. 


326 


DESCRIPTION  OP  DIESEL  ENGINES 


Oils  such  as  Texas,  Mexican  and  California  natural  crudes,  some  of 
which  cannot  be  used  satisfactorily  on  steam  boilers,  -are  easily  handled 
in  the  Allis-€halmers  Oil  Engine,  due  to  the  above  stated  features.  The 
choice  between  the  fuel  oils  available  is  therefore  determined  solely  by 
the  relative  cost,  heat  value,  and  convenience  in  handling. 

As  will  be  seen  by  the  illustration,  the  construction  is  of  horizontal 
design,  which  permits  a  .simple  valve  gear  arrangement.  The  motion 
is  transmitted  from  a  single  eccentric  to  the  inlet  and  exhaust  valves  by 
rolling  contact  levers,  which  has  proven  toy  gas  engine  practice  to  be 
the  quietest  and  most  durable  valve  gear  known.  The  use  of  vertical 
valves,  which  are  always  central  with  the  control  seats,  insures  tight 
valves  and  avoids  the  frequent  grinding  necessary  with  horizontal  valves, 


0 


Valve  Gear  Diagram,  Allis-Chalmers  Oil  flnoine 


due  to  side  wear  on  the  stems  and  the  consequent  change  in  valve  posi- 
tion in  relation  to  the  seat. 

The  exhaust  valve  is  pliaced  in  the  bottom  of  the  cylinder  head,  be- 
tween the  injection  nozzle  and  the  cylinder,  so  that  any  dirt  in  the  fuel 
oil  will  drop  out  through  the  exhaust  without  reaching  the  lubricated 
cylinder  walls.  This  location  is  also  favorable  for  scavenging  any  dirt 
out  of  the  cylinder  during  the  exhaust  stroke. 

The  injection  air  is  furnished  by  a  multi-stage  compressor,  mounted 
on  the  side  of  the  main  frame  and  driven  directly  from  a  crank  on  the 
end  of  the  main  shaft.  The  compressor  is  equipped  with  coils  for  inter- 
cooling  the  air  in  conjunction  with  the  usual  water-stage  cooling. 


DESCRIPTION  OF  DIESEL  ENGINES  327 

The  engine  is  eliminated  from  all  high  pressure  bottles  in  use  on 
most  Diesel  engines,  receiving  its  starting  air  direct  from  the  compressor. 
This  separate  system  of  air  starting  permits  the  use  of  pressure  from 
225  to  250  pounds.  The  engine  is  started  by  opening  a  throttle  valve 
which  admits  the  starting  air1  from  storage  tank,  to  mechanically  oper- 
ated distributing  valves,  which  are  entirely  separate  from  the  main  valve 
gear.  It  is  not  necessary  to  make  any  change  in  the  compression  or 
operation  of  the  valve  gear  in  starting. 

By  referring  back  to  the  Snow  Oil  Engine,  we  find  a  similarity  exist- 
ing to  that  employed  on  the  Allis-Chalmers  type.  The  arrangements  for 
starting  the  engine  are  as  follows: 

An  air  storage  tank  of  ample  capacity  is  provided  and  is  supplied 
with  air  at  from  150  to  200  pounds  from  the  spraying  compressor  on  the 
engine.  Each  cylinder  is  fitted  with  an  air-starting  valve  located  in  the 
cylinder  head  directly  below  the  spray  valve,  and  driven  by  a  cam  on 
same  shaft  with  the  inlet  and  exhaust  valve  cams.  A  single  lever  and 
quadrant  serves  to  control  the  air-starting  valve,  compression  relief,  and 
spray  valves.  With  the  lever  in  central  and  neutral  position,  both  the 
air-starting  valve  is  engaged  and  an  auxiliary  cam  is  shifted  into  con- 
tact with  the  exhaust  valve  lever,  by  means  of  Which  the  exhaust  valve 
is  held  open  for  a  longer  period  of  time  and  the  cylinder  compression 
lowered,  reducing  the  resistance  of  the  engine  to  rotation.  Five  or  six 
revolutions  of  the  engine  on  air  is  sufficient  to  increase  the  air  pressure 
in  the  pipe  between  the  air  compressor  and  the  spray  valve  to  that  re- 
quired for  spraying  the  oil.  The  governor  fuel  pump  lever  is  then 
shifted  to  place  the  pump  in  operation  and  the  main  operating  lever 
moved  from  the  inner  to  the  outer  position.  The  movement  disengages 
the  air-starting  valve  and  the  compression  relief  cam,  and  puts  the  spray- 
valve  in  operation,  when  the  engine  immediately  begins  to  operate  on 
the  fuel  and  is  ready  to  take  the  load.  The  air  storage  tank  can  then 
be  recharged  by  the  compressor  on  the  engine. 

As  will  be  observed  on  either  Allis-Chalmers  as  well  as  the  Snow  Oil 
Engine,  high  pressure  bottles  for  the  air  storage  is  unnecessary.  For 
the  initial  start  and  for  emergency  purposes  afterward,  a  small  inde- 
pendent compressor  is  used  on  the  Snow  Oil  Engine,  driven  by  a  kero- 
sene or  gasoline  engine,  may  be  furnished.  This  is  only  for  use  in  making 
the  first  start  and  afterward  in  the  event  of  the  air.  pressure  in  the  stor- 
age tank  being  lost  through  carelessness  or  otherwise. 

Cooling  Water:  The  amount  of  cooling  water  required  varies  in- 
versely with  the  difference  in  temperature  of  the  water  as  it  enters  and 
leaves  the  cooling  jackets.  It  also  varies  with  the  load  on  the  engine. 
Assuming  a  40  degree  Fahrenheit  rise  from  suction  to  discharge  temper- 
atures, from  6  to  7  gallons  per  horsepower  hour  are  required.  When 
fairly  pure  water  is 'available  the  discharge  temperature  may  be  main- 
tained at  140  degrees  Fahrenheit.  If,  however,  the  water  has  a  tendency 
to  deposit  scale  in  the  jackets,  the  discharge  temperature  should  not  be 
over  120  degrees  Fahrenheit,  For  this  reason,  and  particularly  for  hot 


328  DESCRIPTION  OF  DIESEL  ENGINES 

climates,  where  the  temperature  of  the  inlet  water  is  high,  it  is  desir- 
able to  provide  for  a  cooling  water  supply  of  from  10  to  12  gallons  per 
horsepower  hour. 

For  engines  without  water-cooled  pistons,  a  pressure  of  from  8  to  10 
pounds  per  square  inch  is  sufficient.  For  supplying  water-cooled  pistons 
the  pressure  should  be  from  12  to  15  Ibs.  per  square  inch. 

Where  the  water  supply  is  limited,  cooling  iponds  or  towers  may  be 
used  and  the  same  water  circulated  continuously  through  the  system,  so 
that  only  a  small  amount  of  fresh  water  will  be  required  to  make  up  the 
loss  due  to  evaporation. 


DESCRIPTION  OP  DIESEL  ENGINES 


329 


330 


DESCRIPTION  OF  DIESEL  ENGINES 


THE  STANDARD  FUEL  OIL  ENGINE 


For  mechanical  simplicity  probably  the  two-cycle  crankcase  com- 
pression engine  leads  all  other  types  of  internal  combustion  engines. 
Due,  however,  to  the  relatively  small  amount  of  scavenging  air  which 
can  be  handled  by  this  system,  it  being  possible  to  displace  not  over 
60  per  cent  of  the  main  cylinder  volume,  and  to  the  restrictions  imposed  on 
accessibility  by  the  necessity  of  'a  tight  crankcase  of  minimum  volume, 
this  type  is  barred,  except  for  the  smaller  sizes. 

Next  in  line  for  mechanical  simplicity  stands,  we  believe,  the  stepped 
piston  two-cycle  type  employing  port  scavenging.  Moreover,  with  this 
type,  the  restrictions  on  scavenging  air  do  not  exist.  In  the  Standard 
engine  pure  air  of  more  than  one  and  one-half  times  the  volume  of  the 
main  cylinder  is  forced  into  it  each  working  stroke.  Also,  again  rather 
than  loss  of  accessibility  is  effected,  as  has  already  been  pointed  out. 


Exhaust  Side  of  Two-Cylinder  Vertical  Standard  Engine 

The  adoption  of  the  two-cycle  port  scavenging  principle  of  operation 
not  only  eliminates  the  complication  of  inlet  and  exhaust  valves  and 
gear  and  the  time  required  for  inspection  and  grinding,  but  also  permits 
the  cylinder  head  to  be  much  smaller  and  more  simple  casting. 


DESCRIPTION  OF  DIESEL,  ENGINES  331 

The  fuel  pump  of  the  Standard  engine  is  of  the  variable  stroke  type 
and  requires  'for  its  control  no  wedges,  lever,  etc.,  as  it  is  driven  direct 
by  a  Rites  type  of  inertia  governor,  the  same  as  is  commonly  employed 
for  operating  the  valve  of  a  simple  steam  engine. 

Also  the  injection  air  compressor  is  a  very  simple  mechanical  struc- 
ture, although  meeting  all  the  requirements  of  a  good  compressor  design. 
Due  to  the  suction  and  discharge  valves  'being  combined  in  one  unit  and 
in  the  case  of  the  high  stage  cylinder,  this  unit  being  located  in  the  end 
of  the  cylinder  bore,  there  results  a  cylinder  casting  with  but  one  valve 
pocket.  Placing  of  the  inter  and  after  cooler  coils  in  the  water  jacket 
space  of  the  cylinder  eliminates  several  high  pressure  joints  and  also 
results  in  a  compressor  with  no  hot  pipes  with  which  the  operator  can 
come  in  contact,  and  from  which  the  high  pressure  air  is  discharged  at 
but  a  few  degrees  above  the  temperature  of  the  incoming  cooling  water. 

It  will  be  readily  admitted  that  other  things  being  equal,  a  simple 
mechanism  will  naturally  be  more  reliable  in  operation  than  one  of 
greater  complications.  Other  features  of  the  Standard  Engine  which  de- 
serve mention  here  are: 

(a)  The  very  ample  size  of  all  bearings  and  other  working  parts. 
For  instance,  with  a  working  cylinder  of  only  10^  inches  diameter,   a 
main  bearing  of  6^4  inches  diameter  is  employed. 

(b)  The  conservative  manner  in  which  the  engine  is  rated.    At  full 
rated  load  less  than  80  pounds  M.E.P.  is  required,  as  against  average 
Diesel  practice  of  about  100  pounds.    This  makes  for  low  maximum  tem- 
peratures and  when  employed  with  the  large  excess  of  cool  scavenging 
air  blown  into  the  cylinder,  each  stroke  results  in  low  mean  tempera- 
tures during  the  complete  cycle.    With  normal  inlet  air  temperatures,  the 
exhaust  at  full  load  is  less  than  400  degrees  Fahrenheit. 

The  desirability  of  low  mean  effectives  in  order  to  secure  low  mean 
temperatures  is,  we  believe,  sufficient  reason  for  barring  devices  for 
obtaining  what  is  known  as  super  compression,  even  if  the  extra  com- 
plications of  such  devices  were  not  considered. 

(c)  The  employment  of  the  stepped  piston  which  serves  not  only 
to  furnish  a  liberal  supply  of  air  for  cleaning  and  filling  the  main  cylin- 
der, but  which  also  acts  as  a  cross-head,  thus  insuring  longer  life  to  the 
main  cylinder,  since  it  receives  no  connection  rod  thrust.    Also  the  main 
piston  being   relieved  of  the  pin   and   heavy  bosses   for  carrying  same 
becomes  an  absolutely  symmetrical  member  much  better  fitted  to  resist 
the  pressures  and  temperatures  to  which  it  is  subjected. 

The  use  of  the  stepped  piston  also  tends  materially  to  improve  crank 
case  conditions  and  to  lower  crankcase  temperatures  as  any  blow  past 
the  main  piston  will  be  caught  in  the  scavenging  cylinder.  The  use  of  a 
two-piece  main  piston  also  serves  to  the  same  end  by  preventing  radia- 
tion from  the  hot  piston  head  to  the  interior  of  the  crankcase.  Under  all 
conditions  of  operation  the  crankoase  will  be  found  clean,  cool  and  free 
from  oil  vapor. 


332 


DESCRIPTION  OF  DIESEL  ENGINES 


Detail  Description — Vertical  Type 


Box  Frame:  As  previously  explained,  the  Standard  engine  is  of  the 
vertical  single  acting  two-cycle  valveless  type  of  Diesel  power.  A  single 
box  frame  forms  a  common  support  for  both  the  main  working  cylinders 
and  the  injection  air  compressor  cylinder.  On  account  of  the  through 
bolts  used  between  cylinder  flanges  and  base  plate,  this  frame  is  not 
subjected  to  heavy  tension  strains  and  very  liberal  openings  may  there- 
fore be  provided  for  inspection  and  adjustment  of  bearings. 


Transverse  Section  Through  Main  and  Scavenging  Cylinder 


In  addition  to  the  large  cover  plates  at  front  and  rear,  smaller  in- 
spection plates  are  also  provided  through  which  the  operator  can  con- 
veniently ascertain  the  temperature  of  the  various  bearings. 


DESCRIPTION  OF  DIESEL  ENGINES 


333 


334 


DESCRIPTION  OF  DIESEL  ENGINES 


Air  Compressor:  The  high  pressure  air  required  for  injecting  the  fuel 
into  the  combustion  space  is  furnished  by  a  two  stage  compressor  which 
is  mounted  on  one  end  of  the  box  frame  and  is  driven  directly  from  the 
crankshaft.  A  stepped  piston  is  used  to  obtain  the  necessary  displace- 
ments for  the  different  stages.  The  connecting  rod  and  its  bearings  are 
of  very  liberal  proportions.  They  conform  in  design  to  the  similar  parts 
for  the  main  working  cylinder. 

Both  the  low  stage  suction  and  discharge  valve  are  located  in  a  single 
pocket  at  the  side  of  the  cylinder.  This  pocket  is  so  positioned  as  to 
make  it  impossible  for  a  valve  to  get  into  the  cylinder  due  to  either  a 
broken  valve  spring  or  stem,  and  yet  the  clearance  volume  is  less  than 
two  per  cent  of  the  cylinder  displacement. 


Section  Through  Air  Compressor  Cylinder 


DESCRIPTION  OP  DIESEL  ENGINES  335 

The  valve  cage  for  the  high  stage  valves  is  located  in  the  upper  end 
of  the  cylinder  bore  anc^  with  its  cover  forms  the  cylinder  head.  This 
cage  is  also  arranged  so  that  there  is  no  possibility  of  a  valve  getting 
into  the  cylinder  and  wrecking  the  machine. 

After  being  compressed  in  the  first  cylinder  and  before  going  to  the 
second,  also  after  the  second  compression  the  air  is  thoroughly  cooled. 
The  inter  and  after  coolers  consist  of  coils  of  copper  tubing  and  are  en- 
closed in  the  water  jacket  space  of  the  compressor  cylinder  through 
which  all  the  cooling  water  passes  before  going  to  the  main  cylinders. 
With  this  arrangement  there  are  no  hot  pipes  for  the  accumulation  of 
carbon  deposits  and  the  high  pressure  air  as  it  leaves  the  compressor  is 
at  practically  the  temperature  of  the  inlet  cooling  water.  Also  after 
each  compression  provision  is  made  for  separating  any  entrained  oil 
vapor  or  moisture  from  the  air. 

Scavenging  Air  Compressor:  The  air  pressure  for  scavenging  the 
mam  wonting  cylinder  is  generated  in  -the  annular  space  above  the  cross- 
iiead  and  scavenging  piston  and  around  the  main  piston  barrel.  Because 
or  its  small  clearance,  the  volumetric  efficiency  of  this  pump  is  well  over 
bu  per  cent,  and  as  the  area  of  this  annular  space  is  considerably  greater 
tnan  the  area  of  the  main  cylinder,  an  ample  quantity  of  pure  air  for 
cleaning  and  filling  the  working  cylinder  is  insured. 

The  valves  for  both  suctions  and  discharge  are  of  the  plate  type  and 
operate  under  very  slight  differences  of  pressure.  AS  the  areas  through 
the  valves  and  through  all  ports  and  passages  are  very  liberal,  the  scav- 
enging air  is  handled  with  the  minimum  amount  of  work,  and  as  a  result 
the  overall  mechanical  efficiency  of  the  engine  is  high,  comparing  very 
tavorabiy  with  the  best  four-cycle  engine  practice. 

Scavenging  Manifold:  The  scavenging  manifold  which  extends  across 
the  front  of  the  engine  contains  the  pockets  in  which  are  located  the 
suction  and  discharge  valvesi  of  the  scavenging  pumps,  also  the  passage 
through  which  the  air  is  distributed  to  the  working  cylinders.  This  pas- 
sage is  of  ample  area  so  as  to  cause  the  minimum  of  air  friction.  A  large 
plate  directly  over  each  valve  pocket  permits  of  easy  access  to  the  valves, 
'io  the  bottom  of  scavenging  manifold  is  fixed  the  suction  pipe  through 
which  the  air  is  drawn  to  the  scavenging  pump.  The  sound  of  the  air 
suction  can  be  quite  effectively  muffled  by  means  of  a  screen  at  the  end 
of  tne  pipe  or  if  desired  the  pipe  can  be  continued  to  the  outside  of  the 
building. 

Exhaust  Manifold:  The  exhaust  manifold  is  thoroughly  water  jack- 
eted  for  its  entire  length,  thus  preventing  heating  up  the  engine  room 
in  warm  weather.  The  passage  for  exhaust  gases  is  of  very  liberal  area 
so  as  to  cause  no  harmful  back  pressure  on  the  engine. 

Fuel  Pump:  The  fuel  measuring  pump  is  of  the  variable  stroke  type, 
a  separate  plunger  is  provided  for  each  cylinder.  The  plunger  stroke  is 
controlled  automatically  by  the  governor.  This  governor  is  ordinarily 
set  to  give  a  total  speed  variation  of  4  per  cent  between  full  and  no 


336  DESCRIPTION  OF  DIESEL  ENGINES 

load,  but  is  capable  of  considerable  closer  regulation  if  conditions  neces- 
sitates the  adjusting  of  the  same. 

Fuel  Injection  Valve:  The  fuel  valve  is  of  closed  nozzle  design.  The 
proportions  of  the  various  parts  have  been  determined  by  careful  experi- 
ment so  as  to  have  the  fuel  not  only  thoroughly  broken  up  into  small 
particles,  but  also  to  have  it  well  mixed  with  the  injection  air.  That 
this  result  has  been  attained  is  evidenced  by  the  low  fuel  consumption 
and  clear  exhaust  at  the  various  loads  and  with  fuel  and  crude  oils  of 
widely  varying  characteristics.  The  needle  valve  is  made  from  Tungsten 
steel  carefully  hardened  and  ground.  It  is  thus  well  suited  to  resist  both 
the  chemical  action  of  impurities  in  the  oils,  and  mechanical  wear  of 
the  packing. 

Camshaft  and  Gears:  The  camshaft  is  mounted  in  brackets  support- 
ed from  the  cylinder  jackets.  It  is  so  located  that  the  fuel  valve  can  be 
operated  directly  through  a  single  bell  crank,  but  it  is  so  positioned  that 
it  does  not  have  to  be  disturbed  in  any  way  when  removing  a  cylinder 
head  or  piston.  It  is  driven  from  a  vertical  shaft  by  a  set  of  mechanical 
miter  gears  which  are  cut  from  steel  forgings.  The  vertical  shaft  gets 
its  motion  from  the  main  shaft  through  a  set  of  spiral  gears. 

Air  Starting:  For  starting,  compressed  air  is  admitted  to  each  work- 
ing cylinder  through  an  automatic  check  valve  in  the  cylinder  head.  The 
air  is  properly  timed  by  individual  starting  valves  located  just  below  the 
camshaft  and  each  in  front  of  the  cylinder  which  it  supplies.  These 
valves  are  put  in  operation  toy  the  starting  air  pressure  and  automatically 
go  out  of  operation  as  soon  as  the  starting  air  is  shut  off  at  the  main 
control  valve.  The  engine  can  be  started  on  an  air  pressure  as  low  as 
one  hundred  and  fifty  pounds. 

Lubrication:  The  lubrication  of  the  Standard  engine  is  accomplished 
by  a  force  feed  oil  pump.  The  feeds  to  the  various  parts  are  from  cen- 
trally located  sight  feeds,  where  the  operator  may  ait  all  times  be  en- 
abled to  observe  proper  functioning  of  the  system. 


EFFICIENCY    PERFORMANCES   OF   STANDARD   DIESELS 

The  first  two  charts  in  figure  (a)  show  average  Diesel  engine  prac- 
tices for  both  the  two  and  four-stroke-cycle  types,  and  the  third  shows 
the  distribution  of  work;  in  the  Standard  engine  when  operated  on  250 
R.P.M.  and  rated  50  B.H.P.  per  cylinder.  The  low  percentage  of  work 
for  operating  the  scavenging  pumps  is,  as  already  mentioned,  largely  due 
to  the  employment  of  an  exceptionally  low  scavenging  air  pressure. 
While  the  reduction  in  work  required  for  driving  the  injection  air  com- 
pressor is  attributed  to  a  design  of  atomizer  in  which  not  only  is  the 
pressure  required  very  moderate,  owing  to  a  minimum  number  of  re- 
stricted passages,  but  also  the  volume  of  injection  air  required  is  con- 
siderably reduced. 


DESCRIPTION  OF  DIESEL  ENGINES 


337 


The  slightly  lower  mechanical  losses  are  explained  by  the  ideal  con- 
ditions, both  as  to  temperature  and  lubrication,  under  which  all  bearings 
and  rubbing  surfaces  operate. 

In  Figure  (b)  are  reproductions  of  indicator  diagrams)  taken  at  va- 
rious loads  with  the  engine  operating  at  250  R.P.M.  The  curves  in  Figure 
(i)  show  the  results  of  fuel  consumption  tests  on  the  100  H.P.  two-cyl- 
inder- machine  when  operated  at  different  loads  and  speeds.  As  would 
be  expected,  owing  to  the  longer  time  allowed  for  combustion  and  the 


Mechanical  /osses 
14  % 


Air  compressor 
10  % 


Mechanical  /osses 
12  % 


Air  compressor 


Scavenging  our 
pump    10  % 


Mechanical  /osses 
10.4  % 


Air  compressor 
64% 


A  B 

Figure  (a)  Comparison  of  Mechanical  Efficiencies.  A — Usual  Four-Cycle 
Diesel;  B — Two-stroke-cycle  Diesel;  C — Standard  Two-stroke-cycle 
Diesel 


slightly  ihigher  mechanical  efficiency,  somewhat  better  results  are  shown 
at  the  lower  speeds.  However,  that  the  difference  is  as  slight  as  shown, 
speaks  very  well  indeed  for  the  perfection  of  the  design  as  to  these  two 
features. 

When  comparing  these  fuel  consumption  figures  with  others  pub- 
lished, it  should  be  borne  in  mind  that  they  are  for  a  cylinder  of  but 
10 3/4 -inches  bore.  For  a  cylinder  of  twice  this  diameter,  which  comes 
nearer  the  sizes  on  which  figures  are  usually  found,  the  results  should 
be  nearly  10  per  cent  lower. 

In  disapproval  of  the  statement  sometimes  made  that  owing  to  the 
more  frequent  power  impulses,  the  two-stroke-cycle  engine  operates  with 
exceedingly  high  temperatures,  the  following  figures  as  to  exhaust  tem- 
perature of  the  Standard  engine  are  cited.  With  the  engine  in  each 
case  developing  100  H.P.,  the  exhaust  temperatures  were  as  follows: 
At  225  R.P.M. ,  345  degrees  Fahrenheit;  at  250  R.P.M.,  325  degrees  Fahr- 


338 


DESCRIPTION  OF  DIESEL  ENGINES 


enheit;  at  275  R.P.M.,  315  degrees  Fahrenheit;  at  300  R.P.M.,  305  degrees 
Fahrenheit.  While  the  temperatures  are  exceedingly  low  at  all  speeds, 
it  is  found  that  for  the  same  delivered  horsepower  the  lowest  tempera- 
ture result  from  the  more  frequent  and  light  power  impulses  rather 
than  the  reverse.  This,  the  builders  of  the  Standard  engine  state,  is  in 
accordance  with  theory  and  should  be  the  case  for  a  properly  designed 
machine.  For  not  only  does  the  theoretical  efficiency  of  the  Diesel  cycle 
improve  as  the  size  of  fuel  charge  is  reduced,  but  there  is  also  a  larger 


Figure  (&)     Indicator  Diagrams  at  Various  Loads 


volume  of  cool  air  passing  through  the  cylinder  per  unit  of  time.  For 
the  reasons  cited  they  emphasize  very  strongly  the  desirability  of  em- 
ploying lighter  fuel  charges  and  have  adopted  ratingj  requiring  mean 
effective  pressures  of  about  75  Ibs.,  as  against  the  usual  Diesel  practice 
of  80  to  100  .pounds. 

This,  it  is  contended,  is  the  logical  manner  for  utilizing  the  admitted 
advantages  of  the  two-cycle  principle  and  of  obtaining  a  machine  which 


DESCRIPTION  OF  DIESEL  ENGINES 


339 


with  high  thermal  efficiency  shall  also  combine  the  even  more  important 
requisite  of  unfailing  reliability. 

In  the  following  description  of  the  horizontal  type  of  the  product 
of  the  Hadfield-Penfield  Steel  Co.,  of  Bucyrus,  Ohio,  a  clear  detailed  in- 
formation will  be  given  of  the  Standard  Horizontal  Diesel  Engine. 

This  particular  type  of  engine  follows  the  two-cycle  principle,  and  is 
found  satisfactory  on  horizontal  construction.  In  summing  up  the  advan- 
tages gained  in  two-cycle  construction,  following  is  claimed:  For  a  given 
size  cylinder  the  horsepower  output  would  be  nearly  double  and  at  the 
same  time  this  result  would  be  obtained  with  fewer  working  parts. 

The  .frame  ds  of  center  crank  type  with  heavy  box  section  walls.  This 
casting  also  includes  the  scavenging  air  cylinder  in"  which  a  differential 
or  stepped  piston  operates,  furnishing  the  air  for  cleaning  and  filling  the 
main  cylinder.  Since  the  main  or  working  cylinder  extends  into  this 
larger  cylinder  for  about  one-half  its  length,  the  machine  is  practically 
all  contained  within  this  one  casting,  making  a  very  massive  and  rigid 
construction. 

The  cylinder  head  is  comparatively  small  and  very  simple  casting 
of  symmetrical  design.  There  is  but  one  opening,  which  extends  through 
both  walls;  this  is  for  the  fuel  spray  valve  and  is  located  at  the  exact 
center.  In  addition  to  its  symmetrical  shape  the  casting  is  properly 


IOO       IIO      120     130 


50  75 

Horsepower 

Fig.  (c)     Curves  Showing  Fuel  Consumption  at  Different  Loads 
and  Speeds 

water  jacketed  so  that  the  danger  of  cracks  developing  is  reduced  to 
the  minimum. 

The  combustion  space  which  is  formed  by  the  inner  wall  is  practi- 
cally a  half  Siphere,  which  is  an  ideal  form,  as  it  insures  the  most  rapid 
mingling  of  the  fuel  spray  with  the  air  for  burning,  and  hence  early  and 
complete  combustion. 

Close  fitted  piston  and  rings  are  features  highly  commendable.  To 
make  permissible  these  close  fits,  the  pistons  are  water-cooled  in  all 


340  DESCRIPTION  OF  DIESEiL  ENGINES 

except  the  very  small  sizes  of  cylinders.  An  overheated  piston  may  de- 
velop cracks,  may  expand  sufficiently  to  bind  and  score  the  cylinder,  or 
may  even  stick  fast,  wrenching  off  connecting  bolts  or  rod  bolts  and 
wrecking  the  whole  machine.  Water  cooling  eliminates  the  possibility 
of  such  troubles  and  at  the  same  time  makes  the  proper  lubrication  of 
piston  much,  easier,  and  reduces  the  amount  of  oil  required.  As  the  pis- 
ton pin  is  located  in  the  larger  air  pumping  piston,  the  main  piston  is 
relieved  of  all  connecting  rod  thrust,  and  therefore  the  wear  in  the  main 
cylinder  is  slight. 

Identical  two-stage  compressor  arrangement  are  on  the  horizontal  as 
on  the  vertical  types  of  Standard  Diesels.  The  high  pressure  air  re- 
quired for  injecting  the  fuel  into  the  combustion  space  is  furnished  by 
a  two-stage  pump  mounted  on  the  side  of  the  frame  casting,  and  driven 
by  a  small  crank  on  the  end  of  the  main  shaft.  The  air  from  the  first 
stage  of  this  pump  is  delivered  into  tanks  at  about  150  pounds  pressure, 
and  is  available  for  starting  the  engine.  From  these  tanks  the  air  is 
admitted  to  the  second  stage  of  the  air  pump  and  thence  direct  to  the 
fuel  valve  without  intermediate  receiver.  As  the  first  stage  of  the  pump 
takes  its  air  from  the  scavenging  air  cylinder  at  about  five  pounds  pres- 
sure rather  than  from  the  atmosphere,  we  have  in  reality  a  three-stage 
compression.  This  air  pump  is  well  proportioned  for  these  tyipes  of 
engines  and  will  furnish  air,  even  if  not  properly  kept  up.  The  front 
end  of  the  first  stage  piston  has  an  extension  in  the  form  of  a  piston 
valve.  This  extension  acts  both  as  a  crosshead  for  the  air  pump  and 
also  controls  the  suction  and  discharge  of  air  from  the  large  scavenging 
cylinder. 

The  fuel  nozzle  is  of  the  open  type;  that  is,  the  fuel  is  pumped  into 
a  small  receptacle  which  is  at  all  times  in  open  communication  with  the 
combustion  chamber.  This  fuel  receptacle  is  placed  just  ahead  of  the 
mechanically  operated  timing  valve  which  controls  the  admission  of  in- 
jection air.  When  the  timing  valve  opens  the  fuel  is  picked  up  by  the 
injection  air  and  blown  past  the  stationary  atomizer  into  the  combustion 
chamber.  The  open  nozzle  construction  has  the  following  advantages: 

(1)  The  fuel  pump  has  only  to  work  against  low  pressures  as  it  is 
timed  to  operate  when  the  main  piston  is  at  the  opposite  end  of  the  cyl- 
inder; the  pump  thus  becomes  in  reality  only  a  measuring  device.     The 
plunger  can  be  packed  very  loosely  and  better  regulation  can  be  secured 
on  account  of  the  light  load  on  the  governor. 

(2)  As  only  pure  air  passes  the  timing  valve,  the  seat  will  remain 
tight  much  longer  than  where  air  and  fuel  both  are  injected  through  the 
valve. 

(3)  Better  atomizing  is  secured,  as  the  heated  air  which  is  driven 
back  in  contact  with  the  oil  tends  to  vaporize  it,  and  we  do  not  there- 
fore have  to  depend  entirely  upon  mechanical  action  in  breaking  up  the 
fuel.     The  valve  cage,  atomizer,  etc.,  are  made  from  nickel  steel,  as  this 
material  best  resists  the  chemical  action  of  the  impurities  frequently 
found  in  the  crude  oils. 


DESCRIPTION  OF  DIESEL  ENGINES  341 

These  engines  are  guaranteed  continuously  without  undue  heating 
their  full  rated  horsepower.  The  ratings  given  hold  for  an  elevation  of 
not  to  exceed  1,000  feet  above  sea  level.  For  higher  altittides  the  capac- 
ities will  somewhat  decrease. 

The  Standard  engine  is  offered  subject  to  the  guarantee  that  its 
fuel  consumption  shall  not  exceed  following  quantities  of  crude  or  cheap 
fuel  oils. 

At  full  load .50  Ibs.  per  B.H.P.  hour. 

At  three-fourths  load .52  Ibs.  per  B.H.P.  hour. 

At  one-half  load .58  Ibs.  per  B.H.P.  hour. 

This  consumption  is  based  on  a  sea  level  rating  and  a  fuel  of  at  least 
18.000  B.T.U.  (low  heating  value)  per  pound. 


342 


DESCRIPTION  OF  DIESEL  ENGINES 


LOMBARD    ENGINES 

The  cross-section  views  of  the  Lombard  engines  disclose  the  type 
of  engine  built  with  the  object  in  view  to  act  as  a  power  producer  where 
reliability  is  of  highest  importance.  These  engine's  are  of  the  vertical, 
.multi-cylinder,  heavy  duty  type,  with  pistons,  rings,  connecting  rods, 
bearings  and  crankshaft  all  easily  accessible  through  the  front  housing 
doors  of  the  enclosed  crank  case. 


Cross-Sectional  View  of  Lombard  Engine. 


DESCRIPTION  OP  DIESEL  ENGINES 


343 


Illustration  demonstrating  the  accessibility  of  Lombard's  Vertical 
Multi-cylinder  Diesel  Engines. 

This  unusual  accessibility  results  from  the  design  of  the  cylinders 
with  removable  skirt  section  bolted  to  the  bottom  of  each.  With  the 
crank  on  'bottom  center  and  skirt  detached  from  cylinder  casting,  any 
piston  with  its  connecting  rod,  can  be  swung  forward  through  the  crank 
case  door  opening,  without  removing  cylinder  head,  disconnecting  crank 
pin  box,  dismounting  valve  gear  or  otherwise  disturbing  adjustments 
which  it  is  desirable  to  preserve. 

Other  advantages  of  this  construction  are  that  it  (1)  avoids  the 
objectionable  joint  in  the  combustion  chamber  exposed  to  high  tempera- 


344  DESCRIPTION  OF  DIESEL  ENGINES 

tures  and  pressures,  the  joint  between  cylinder  and  skirt  sections  being 
subjected  only  to  exhaust  temperatures  and  pressures;  (2)  eliminates 
the  mass  of  metal  necessary  for  a  cylinder-and-head  joint,  thereby  se- 
curing a  much  freer  movement  of  the  cylinder  wall  to  take  care  of  ex- 
pansion and  contraction  and  providing  ample  and  unrestricted  space 
for  circulation  of  cooling  water;  (3)  permits  the  accessible,  overhead 
location  of  cam  shaft  with  cams  running  in  oil  and  with  valves  operated 
by  simple  rocker  arms;  and  (4)  results  in  an  engine  of  pleasing,  sym- 
metrical appearance,  with  simplified  controls  for  starting  and  handling 
a  powerful,  efficient  unit,  which  saves  weight,  head  room,  installation 
and  operating  expense,  upkeep,  fuel  and  lubricating  oil. 

The  engine,  which  is  of  multi-cylinder  construction,  are  equipped 
with  integral  air  compressor  of  balanced  duplex  design  for  supplying  the 
starting  and  injection  air. 

The  frame  sections  which  substantially  enclose  the  crank  case  merely 
support  weight.  The  four  heavy  steel  tie  rods,  which  extend  from  each 
cylinder  to  the  main  bearing  pads  within  the  bed  plate,  carry  the  work- 
ing load  and  relieve  the  frame  of  all  tensile  stresses.  Removal  of  frame 
housing  doors  and  tie  rods  along  the  front  or  air  intake  side,  permits 
rolling  the  main  crank  shaft  out  in  the  space  directly  alongside  of  the 
engine,  without  dismounting  cylinders  or  disturbing  valve  gear. 

All  cylinders  and  bearing  surfaces  are  positively  and  copiously 
lubricated  from  a  pressure  system  which  includes  filters  and  coolers  for 
the  repeated  and  economical  use  of  lubricating  oil. 

Lombard  engines  are  built  in  sizes  ranging  from  60  to  500  B.  H.  P. 
Engines  are  built  for  either  marine  or  stationary  purpose. 


ATLAS-IMPERIAL  SOLID   INJECTION   DIESEL   ENGINES   FOUR- 
CYCLE MARINE  TYPE 

The  rapid  increase  of  small  sized  Diesel  engines  between  50  B.  H.  P. 
and  200  B.  H.  P.  is  primary  due  to  the  record  accomplishments  of  this  re- 
spective class  of  power  producers.  (Specially  adapted  for  coastwise  ser- 
vice aboard  ship  as  auxiliary  driving  mediums  and  on  crafts  mainly  de- 
pending upon  sails. 

Their  recognized  ability  as  a  dependable  and  economic  machine, 
and  above  all  the  surprising  simplicity  in  design  and  construction,  not 
to  mention  the  limited  space  a  machine  of  this  horsepower  capacity  oc- 
cupies, makes  this  generator  of  Diesel  power  a  favored  type. 

Firms,  such  as  the  Worthington  Corporation,  Western  Machine  Co., 
Dow  Pump  &  Diesel  Engine  Co.,  Enterprise  Diesel  Engine  Co.,  Lombard 
Governor  Co.,  Atlas-Imperial  Engine  Co.,  and  in  fact  the  .many  manufactur- 
ers throughout  the  United  States  as  well  as  Europe  have  made  it  possi- 
ble to  convince  the  shipowner  that  Diesel  power  is  as  profitable  for 
small  sized  vessels  as  for  ships  of  large  carrying  capacities. 


DESCRIPTION  OF  DIESEL  ENGINES 


345 


346  DESCRIPTION  OF  DIESEL  ENGINES 

It  will  be  acknowledged  that  only  a  few  years  ago  numerous  ob- 
jectionable features  were  reacting  to  the  detriment  of  adopting  Diesel 
machinery  in  smaller  crafts.  The  principal  reaison  bringing  the  Diesel 
engine  as  an  unfavorable  machine  for  use  on  coastwise  marine  service  or 
aboard  ship  as  an  auxiliary  operating  engine  was  the  lack  of  skilled 
operators  sufficiently  acquainted  with  the  principles  and  mechanism  of 
Diesel  power.  That  this  very  fact  contributed  greatly  in  retarding  the 
adoption  of  this  prime  mover  is  true  to  a  certain  extent.  /Some  of  the 
earlier  types  of  Diesel  engines  were  rather  crude  and  possessed  of  en- 
tirely too  many  contrivances,  such  as  valves,  piping,  etc.,  which  were 
often  the  cause  of  'breakdowns  with  its  consequential  expensive  loss  of 
time  to  the  owner.  In  many  cases  a  special  kind  of  fuel  for  the  engine 
was  necessary,  which  in  itself  proved  disadvantageous.  From  a  mechani- 
cal standpoint  they  were  often  inefficient  and  must  be  acknowledged 
that  the  existing  difference  of  the  modern  types  of  Diesel  engines  in 
comparison  to  those  of  only  a  few  years  ago  show  the  enormous  strides 
Which  have  taken  place  to  bring  the  Diesel  engine  to  its  high  stage  of 
present  day  perfection. 

As  will  be  observed  in  the  specially  selected  types  of  Diesel  mach- 
inery in  this  work,  that  the  simplicity  in  mechanical  arrangements 
have  -been  brought  to  a  stage  that  the  person  with  limited  mechanical 
knowledge  around  Diesel  power  can  be  entrusted  iwith  the  operation  of  a 
machine,  providing  however,  that  his  knowledge  comprises  the  necessary 
ability  upon  which  the  fundamental  laws  of  Internal  Combustion  mach- 
inery exists. 

Often,  troubles  which  arise  around  Diesel  machinery  have  been 
unjustly  blamed  upon  the  machine  and  its  manufacturer,  designer,  etc., 
when  as  a  matter  of  fact  the  engine  has  stood  an  unmerciful  test  before 
being  installed.  After  some  investigation  it  usually  results  in  the  es- 
tablishment of  the  fact  that  the  operator  was  in  an  entire  wrong  place 
and  in  justice  to  the  many  experienced  operators  ought  to  retire  from 
his  chosen  profession  or  occupation. 

Much  could  be  said  on  .this  subject  dealing  with  the  incompetency 
of  the  man  in  charge,  but,  it  will  be  admitted,  that  with  the  introduction 
of  literature  on  the  subject  of  Diesel  operation  and  the  greater  oppor- 
tunity afforded  to  day  to  receive  a  better  training  in  this  branch  of  en- 
gineering, will  contribute  towards  the  creation  of  better  class  of  men. 

When  carefully  giving  the  Atlas-Imperial  Diesel  engine  some  study 
we  find  that  there  are  points  which  deserve  of  highest  comment.  The 
writers  of  "The  20th  Century  Guide  for  Diesel  Operators"  show  an  en- 
tirely impartial  conduct,  and  it  is  to  be  hoped  that  the  reader  will  not 
labor  under  an  illusion  that  any  special  favors  are  granted  the  numerous 
firms  which  are  giving  space  in  this  work.  As  previously  stated,  every 
firm  illustrated  in  this  book  are  selected  by  their  merits  and  are  known 
the  world  over  as  reliable  manufacturers. 

The  Atlas-Imperial  Diesel  engine  is  of  the  four-cylinder,  four-cycle 
vertical  type,  having  enclosed  crankcase,  valves  in  the  head,  fitted  with 
heavy  duty  reversing  gear,  and  force  feed  lubricating-system, 


DESCRIPTION  OF  DIESEL  ENGINES 


347 


348  DESCRIPTION  OP  DIESEL  ENGINES 

To  the  operator  experienced  with  gasoline-driven  engines,  the 
"valve-in-head"  arrangement  will  sound  familiar.  It  will  be  of  interest 
here  to  give  a  little  explanation  of  the  advantages  claimed  by  builders 
of  valve-in-head  motors  in  contrast  to  L-head  or  T-head  types  of  con- 
struction. 

Unfortunately  it  is  impossible  for  a  Diesel  engine  to  utilize  all  the 
heat  created,  or  'rather  generated  for  power.  If  some  means  were  not 
adopted  to  cool  the  motor  the  heat  would  become  so  great  that  it  would 
be  destructive  to  the  motor. 

So  in  making  the  cylinder  castings,  water  passages  are  cast  around 
the  cylinders  in  such  a  manner  as  to  allow  the  excess  heat  to  escape 
through  the  cylinder  walls,  into  the  water,  which  in  turn  is  cooled  by 
the  circulation  method  of  the  engine.  It  is  quite  evident,  therefore, 
that  the  less  water  jacketing  space  there  is  in  a  motor,  the  greater 
the  thermal  (heat)  efficiency  there  will  be  because  of  smaller  area  of  the 
cylinder  walls  and  combustion  chamber  will  be  exposed  to  the  cooling 
influence  of  the  water. 

This  brings  us  to  the  biggest  reason  for  the  Valve^in-Head  design, 
because  the  arrangement  of  the  valves  permits  of  a  smaller,  more 
compact  combustion  chamber  than  is  possible  in  either  the  L-Head  or  the 
T-Head  type  of  engine.  To  make  this  statement  still  clearer,  it  .should  be 
understood  that  in  all  cases,  both  inlet  and  exhaust  valves  form  a  part 
of  the  combustion  chamber,  where  the  heat  is  the  greatest,  and  in  conse- 
quence it  is  necessary  to  provide  ample  water  jacketing  space  to  the 
heads  and  sides  of  the  cylinders.  In  this  engine  this  is  accomplished 
by  means  of  passover  pipes  causing  the  circulation  of  water. 

Now,  if  we  regard  our  fuel^oil  asi  so  many  heat  units,  it  is  quite 
apparent  that  the  loss  of  these  heat  units  thait  are  wasted  through  the 
water  jacketed  surfaces,  the  more  of  them  will  be  left  in  the  form  of 
actual,  usable  power  directed  against  the  piston. 

Then,  because  of  the  larger  valves  this  type  of  construction  per- 
mits and  can  be  located  in  a  straight  line  above  the  pistons,  the  dead 
exhaust  gases  are  quickly  and  easily  expelled  through  them  at  the  con- 
clusion of  the  working  .stroke,  instead  of  being  forced  around  corners  and 
downward  through  a  much  larger  chamber,  as  in  the  L-Head  and  T-iHead 
types.  And  the  combustion  during  each  working  stroke  is  much  more 
perfect  in  this  type  of  design  because  the  incoming  charges  are  purer. 

The  exhaust  and  inlet  valves  are  mechanically  operated.  The  valve 
head  is  made  of  cast  iron  with  steel  stem.  The  inlet  and  exhaust  valve 
springs  are  interchangeable.  The  valves  are  operated  by  steel  valve 
lifters  provided  with  large  anti-friction  rollers,  these  rollers  are  made 
of  special  alloy  steel,  hardened  and  ground.  The  cams  are  fastened 
to  the  camsJraft  with  keys.  The  cam  shaft  gear  is  16"  diameter  and 
2V2"  face. 

The  engine  is  fitted  with  a  flyball  governor  which  is  of  the  throttling 
type.  The  governor  is  driven  by  spur  gears  direct  from  the  cam  gear- 
ing without  belts  or  frictions  and  is  fitted  with  a  speeding  attachment 


DESCRIPTION  OP  DIESEL  ENGINES  349 

whereby  the  speed  of  the  engine  may  be  changed  as  desired  at  any  time 
while  the  engine  is  in  motion.  The  governor  acts  directly  on  the  spray 
valve  lifters  and  controls  the  amount  of  fuel  delivered  to  the  spray 
valves  in  direct  proportion  to  the  power  developed.  These  governors  are 
very  sensitive  and  quick  of  action. 

The  engine  is  provided  with  a  force  feed  lubricating  system  which 
delivers  oil  at  about  5  Ibs.  pressure  to  all  the  main  working  parts.  The 
oil  is  delivered  from  the  pressure  pump  to  the  main  crankshaft  bear- 
ings, from  which  it  passes  through  the  hollow  crankshaft  to  the  crank- 
pin  bearing,  and  from  there  it  passes  up  the  hollow  connecting  rods  to 
the  piston  pin  bearing.  The  oil  is  then  returned  by  means  of  a  sump 
pump  to  a  strainer  from  which  it  again  passes  through  the  pressure  putnp. 
In  addition  to  this  system  the  engine  is  provided  with  a  multiple  force 
feed  lubricator  connected  with  copper  tubes  to  the  cylinders,  etc. 

The  mechanical  injection  fuel  pumps,  which  are  made  of  steel,  are 
fitted  to  the  engine.  These  ipumps  deliver  the  fuel  under  pressure  to 
the  spray  valves  in  the  center  of  each  cylinder  head. 


350 


DESCRIPTION  OF  DIESEL  ENGINES 


THE   CUMMINS   OIL    ENGINE 
(Di-esel  Type) 

Note:  The  Cummins  Oil  Engine  is  operated  under  the  four-stroke- 
cycle  system.  While  the  engine  resembles  in  its  method  of  power  gen- 
eration the  Diesel  principle,  nevertheless,  when  carefully  studying  this 
machine,  it  will  be  found  that  it  has  exclusive  features,  which  makes  this 
engine  a  distinctive  type  of  its  own. 

Principle  of  Operation:  (1)  The  principle  of  operation  is  briefly 
as  follows: 

On  the  first  stroke  as  the  piston  descends  a  charge  of  pure  air  is 
drawn  through  intake  valve  directly  from  the  outside;  at  the  same  time 
the  same  mechanism  pushes  open  small  fuel  valve  in  fuel  injector  body 
and  permits  a  charge  of  oil  to  ipass  into  cup.  This  amount  of  charge 


Sectional  View   Through  Cylinder  Head  of  Cummins  Four-Cycle,  Valve- 
in-Head,  8  to  32  H.P.  Diesel  Engines. 

which  determines  the  speed,  is  controlled  by  the  hand  throttle  operating 
on  needle  valve. 

(2)  At  the  end  of  this  first  stroke  the  intake  valve  closes  and  the 
piston  comes  up,  compressing  the  charge  of  pure  air  to  the  pressure  ol 
approximately  450  pounds  per  square  inch. 

(3)  This  pressure  causes  the  air  to   instantly  become  heated  to  a 
temperature  of  approximately  1000  degrees  F.,  or  in  other  words,  prac- 
tically red  hot. 

(4)  As  the  temperature  and  pressure  in  fuel  cup  is  the  same  as  that 
in  the  cylinder,  the  fuel  becomes  highly  heated  and  the  small  amount 
of  gas  which  is  in  the  fuel  charge  ignites,  raising  the  pressure  in  the 
cup  to  a  point  considerable  higher  than  that  outside  in  the  cylinder. 


DESCRIPTION  OF  DIESEL  ENGINES  351 

(5)  This  difference  in  pressure  causes  the  heavy  oil  left  in  cup  to  be 
blown  out  into  the  cylinder  in   a  fine  gaseous   spray  which  ignites   in- 
stantly and!  causes  the  expansion  or  working  stroke  of  piston. 

(6)  On  the  fourth  and  last  cycle,  the  exhaust  valve  opens  and  the 
burned  gases  are  expelled  -through  exhaust  valve  into  the  atmosphere. 

A  study  of  the  sectional  view  of  the  illustration  of  the  Cummins 
Oil  engine  should  clarify  this  mode  of  generation. 

(7)  The  fuel  enters  the  fuel  valve  body  at  a  point  marked  "Fuel 
Connection,"   passes   down   around   needle   valve,   which   has   three   flat 
sides,   permitting  free   flow   of  fuel.     In   the   lower   end  of   this   needle 
valve  a  long  hardened  and  ground  taper  seat  fits  into  the  seat  in  fuel 
valve  body.    At  the  top  of  fuel  valve  a  brass  cage  carries  fuel  valve  lever 
and   throttle   lever.     The   throttle   lever   works   a   double   thread    screw 
which  permits  spring  to  lift  needle  valve  off  seat  according  to  opening 
of  throttle  lever. 

(8)  At  the  beginning  of  the   suction   stroke   the   air-inlet  valve  is 
opened  by  the   push  rod,  which   causes   the  small  lever  pinned  to   the 
rocker  arm  to  in  turn  open  the  fuel-admission  valve;     this  permits  the 
proper  amount  of  fuel,  which  is  determined  by  fuel-control  valve,  to  be 
drawn  into  fuel  cup,  where  it  lies  until  the  heat  of  compression  on  com- 
pression stroke  ignites  it. 

A  study  of  the  cut  will  show  that  the  fuel  cup  is  only  exposed  to  the 
heat  of  combustion  chamber  for  a  very  small  margin  around  spray  holes. 
This  is  a  vital  feature  exclusive  of  this  type  of  engine. 

Starting:  An  eccentrically  operated  compression  release  is  fitted  to 
valve  rocker  shaft.  By  throwing  uip  small  lever,  eccentric  inside  rocker 
arm  is  lowered,  holding  exhaust  valve  open.  This  permits  engine  to  be 
revolved  by  starting  crank  on  end  of  crank  shaft  with  no  resistance  ex- 
cept small  amount  of  friction  in  engine.  After  spinning  engine  ovet 
rapidly  several  times,  the  lever  is  dropped,  which  causes  exhaust  valve  to 
seat  properly,  and  the  heavy  flywheel  carries  engine  over  its  first  com- 
pression. This  fires  the  fuel  charge  which  was  admitted  through  the 
valve  and  the  engine  starts  firing. 


352 


DESCRIPTION  OF  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES  353 

SPERRY'S  MARINE  TYPE  HEAVY  DUTY  COMPOUND  DIESEL 

ENGINE 

The  principle  on  which  this  engine  operates  differs.1  vastly  from  any 
motor  now  on  the  market.  It  is  very  ingenious  in  design,  and  experi- 
ences with  the  first  engines  in  coastwise  service  has  demonstrated  its 
suitability  and  economy  equal  to  the  best  of  Diesels  of  same  horsepower 
capacity. 

The  illustration  shows  a  small  marine  type  with  high-pressure  cyl- 
inders 7  inches  by  11  inches,  running  at  400  R.P.M.  The  fuel  ipumps  are 
also  shown  here  and  the  connection  to  the  governor.  The  camshaft  is 


Sperry  Compound  Engine,  Cross-Sectional  View.    Letters  Indicating  Con- 
structive Features  of  Transfer-Valve,  Port  Arrangement,  Pistons,  etc. 


on  a  shelf  at  the  top  of  the  engine  to  one  side  and  is  driven  by  skew- 
gears.  The  electric  generator  forming  the  full  load  of  this  engine  is 
shown  in  the  background  and  one  of  the  transfer  valves  with  its  bonnet 
cover  stands  on  the  floor  in  front  of  the  engine.  The  comparatively 
small  size  of  the  engine  should  meet  with  the  approval  aboard  such 
vessels  where  small  space  allowance  is  of  essential  importance.  The 
construction  is  shown  very  complete  in  this  illustration,  especially  the 
accessibility  and  similarity  to  ordinary  types  of  engines  in  regards  to 
construction. 


354  DESCRIPTION  OF  DIESEL  ENGINES 

Construction  and  Mechanical  Efficiency:  It  remains  to  be  seen,  if 
the  highly  commendable  efforts  of  Mr.  Elmer  A.  Sperry,  M.  E.,  has  by 
the  creation  of  this  latest  addition  of  improved  Diesel  type  solved  the 
question  of  eliminating  excessive  weighty  Diesels  and  substituting  in  its 
place  the  much  lighter  "compound"  type.  If  this  has  been  accomplished 
an  added  interest  will  be  paid  to  the  future  development  of  this  new  type 
in  larger  construction. 

Its  factors  of  established  high  mechanical  efficiency  in  compounding 
Diesels  we  will  undertake  to  briefly  explain. 

We.  are  brought  face  to  face  with  steam  engine  practice  as  prevail- 
ing in  compound  engines.  Compound  engines  are  a  type  where  the  high- 
pressure  is  taking  up  before  entering  the  low  pressure  cylinder. 
Inasmuch  as  the  Diesel  engine  is  a  "constant  pressure"  engine,  where 
the  larger  volume  of  power  gases  in  the  combustion  chamber  of  'the  com- 
pound at  once  solves  a  number  of  important  problems,  makes  the  light 
engine  easy  of  accomplishment,  and  overcomes  a  number  of  difficulties 
at  the  same  time.  In  this  engine  we  have  two  high  pressure  or  combus- 
tion pistons  at  the  ends  and  a  low  pressure  in  the  center.  A  balancing 
cylinder  sustains  a  permanent  connection  with  the  low  pressure  cylinder. 
The  solid  fuel  injection  valve  and  nozzle  are  placed  approximately  over 
the  center  of  gravity  of  the  large  masses  of  air  in  the  so-called  clear- 
ance dome. 

It  is  understood  that  the  two  high-pressure  cylinders  are  operating 
four-cycle,  one  360  degree  back  of  the  other,  discharging  alternately  into 
the  low  pressure,  which  therefore  works  two-cycle  and  delivers  power 
on  each  down  stroke. 


H.P  Cylinder 
'  Expansion 


'Prt-Compressor 


Comparison  in  Compound  Indicator  Card  in  contrast  to  Diesel 
standard  type. 


The  dome,  unlike  the  usual  type  of  Diesels  is  rather  large  and  forms 
an  upward  extension  of  the  'Combustion  cylinder,  extending  also  to  the 
right  in  a  large  sweep  surrounding  a  so-called  "transfer"  valve  which 
seals  the  transfer  port.  A  sleeve-like  induction  valve,  seated  on  top  of 
the  transfer  valve,  is  controlled  by  a  cam-operated  fork.  The  transfer 
valve  and  sleeve  are  lifted  by. a,  fork,  located  in  a  thimble  near  the  top 
of  the  stem.  The  first-stage  annular  compression  pump  surrounding  the 
trunk  piston  below  the  low-pressure  piston  proper,  delivers  its  air  to  a 
small  receiver,  which  in  turn  discharges  to  the  cored  port  surrounding 
the  induction  sleeve. 


DESCRIPTION  OP  DIESEL  ENGINES  355 

The  cooling  is  effected  by  following  method:  In  forcing  the  high- 
pressure  piston  down  air  must  pass  some  port  in  entering.  The  air-cool- 
ing port  is  in  line  with  the  transfer  port  and  the  induction  valve  itself 
rides  on  the  back  of  the  transfer  valve  in  the  form  of  a  hollow  sleeve 
seated  directly  on  the  top  of  the  transfer  valve.  The  back  of  the  transfer 
valve  is  provided  with  greatly  enlarged  radiating  and  cooling  surfaces 
presented  to  this  cooling  air  and  powerful  convection  currents  are  con- 
stantly acting  when  sealed.  Moreover,  this  air  when  entering  is  at 
high  velocity  and  gushes  down  through  and  bathes  the  deeply  serrated 
surfaces  of  the  hack  of  the  transfer  valve,  licking  up  the  heat  very  com- 
pletely in  its  inward  rush. 


THE   STILL   ENGINE 

(Author's  Note. — This  article  is  a  contribution  through  courtesy  of 
the  distinguished  Professor  of  Naval  Architecture  and  Marine  Engineer- 
ing at  the  Lehigh  University,  Bethlehem,  Pa.,  Mr.  L.  B.  'Chapman.) 

As  will  be  observed  byi  the  detailed  description  of  the  Still  engine 
that  it  is  a  combination  Diesel  and  steam  engine,  devised  to  increase 
the  thermal  efficiency  over  that  of  the  Diesel  engine.  The  heat  ordi- 
narily rejected  in  the  jacket  water  and  to  the  exhaust  is  used  to  produce 
steam  and  about  8  per  cent  of  this  heat  is  converted  into  useful  work, 
increasing  the  brake  horsepower  of  the  engine  about  30  /per  cent. 

Whatever  the  future  of  this  engine  may  be,  it  must  be  considered 
from  the  standpoint  of  technical  observation  a  factor  of  highest  con- 
sideration. When  giving  this  engine  some  study,  it  will  be  found  that 
there  are  advantages,  in  particular  in  lessening  fuel  expenditure,  which 
are  deserving  of  comment. 

From  the  diagram  of  the  Still  engine  shown  in  Fig.  1  it  will  be  seen 
that  in  its  present  form  the  engine  is  double-acting  with  the  Diesel  cycle 
working  on  top  of  the  piston.  The  water  jacket  is  connected  in  a  circuit 
with  the  boiler  and  an  exhaust  generator  as  shown  in  the  diagram.  The 
cooling  water  enters  and  leaves  the  jacket  at  a  constant  temperature 
corresponding  to  the  pressure  of  the  steam  in  the  boiler.  The  heat 
absorbed  by  the  jacket  water  surrounding  the  combustion  cylinder  is 
used  to  convert  the  water  into  steam  at  constant  temperature.  In  other 
words,  the  heat  of  combustion  that  radiates  through  the  walls  is  trans- 
ferred into  latent  heat  of  steam.  The  steain  thus  generated  passes  to 
the  boiler.  The  function,  of  the  boiler  is  to  produce  steam  for  warming 
up  and  starting  the  engine  and  to  augment  the  supply  generated  in  the 
jackets,  if  the  jacket  supply  is  not  sufficient  for  the  steam  end  of  the 
cylinder. 

The  boiler  feed  water  is  circulated  through  the  jacket  as  shown  in 
Fig.  1.  The  feed  water  is  taken  from  the  feed  tank  by  the  feed  pump 
as  in  all  steam  plants  and  is  delivered  at  about  100  degrees  to  a  feed 
heater  or  exhaust  generator  where  it  absorbs  the  heat  in  the  exhaust 


356 


DESCRIPTION  OF  DIESEL  ENGINES 


gases.  The  temperature  of  the  feed  water  is  thus  raised  from  100  degrees 
Fahr.  to  between  350  and  450  degrees  Fahr.,  and  the  exhaust  gases  are 
reduced  from  900  to  150  degrees  Fahr.  The  feed  water  then  enters  the 
jacket,  where  it  is  converted  into  steam  by  the  heat  of  combustion. 

The  steam  from  the  boiler  enters  the  lower  part  of  the  cylinder  and 
acts  on  the  piston  in  practically  the  same  manner  as  in  a  steam  engine 
and  is  then  exhausted  to  the  condenser.  Cylinder  condensation,  which  Is 
a  large  loss  with  the  ordinary  steam  engine,  is  practically  eliminated 
in  the  Still  engine  because  of  the  heat  received  from  the  combustion  of 
the  gases  in  the  Diesel  end. 


Stop  Valve 


Fig.  I 


Final  Combustion  Exhaust 
Temp.  I50"F. 


During  compression  of  the  air  on  the  Diesel  side  of  the  piston  the 
air  charge  absorbs  heat  from  the  cylinder  walls  because  of  the  high 
temperature  in  the  jacket.  With  the  straight  Diesel  engine  the  transfer 
is  in  the  opposite  direction,  due  to  the  cold  circulating  water.  One 
result  of  this  is  that  the  required  compression  pressure  is  less  in  the 
Still  engine  than  in  ordinary  Diesel  engines. 

Advantages  of  Combined  Cycles:  The  advantages  due  'to  the  inter- 
,action  of  the  combustion  and  steam  cycles  are  summarized  by  Mr.  F.  E. 
D.  Acland  in  a  paper  before  the  Royal  Society  of  Arts  as  follows: 

(1)  The  mean  temperature  of  the  cylinder  walls  is  higher  than  in 
ordinary  engines;   the   cooler  parts  being  maintained   at  a   higher,  the 
hotter  parts  at  a  lower  temperature. 

(2)  The  piston  is  cooler,  owing  to  the  expansion  of  the  steam  be- 
hind it. 


DESCRIPTION  OP  DIESEL  ENGINES 


357 


(3)  The  heat  efficiency  of  the  combustion  cycle  is  augmented  owing 
to  the  walls  being  at  a  higher  and  constant  temperature,  and  is  in  pro- 
portion to  the  rise  in  temperature  of  the  jacket  water. 

(4)  Frictional  losses  are  reduced  by  the  higher  temperature,  and 
by  the  steam  overcoming  the  inertia  of  the  reciprocating  masses  at  the 
lower  dead  center. 


Fig.  2 — Still  Engine  on  Test  in  Shop 


(5)  The  mechanical  efficiency  of  the  whole  engine  is  higher  than 
that  obtainable  in  a  normal  engine  of  similar  type. 

(6)  The  steam,  expanding  as  it  does  in  a  cylinder  hotter  than  it- 
self, gives  an  indicator  diagram  larger  than  that  theoretically  obtainable 
under  ideal  conditions  in  an  ordinary  steam  engine. 


358  DESCRIPTION  OF  DIESEL  ENGINES 

(7)  Twenty-nine  per  cent  of  additional  brake  horsepower  is  added 
to   the   shaft  of   the   engine   without   increase   in   the   fuel   consumption. 
(Steam  not  condensed.) 

(8)  Forty  per  cent  is  added  when  condenser  is  used.      (Air  pump 
separately  driven.) 

(9)  The  indicated  horsepower  due  to  steam  appears  as  brake  horse- 
power added  to  the  shaft,  all  the  mechanical  losses  having  already  been 
accounted  for  in  measuring  the  combustion  brake  horsepower. 

Besides  the  merits  listed  above  the  two-cycle  'Still  engine  has  the 
following  advantages: 

(1)  Fuel    consumption    10    to    20    per   cent   lower   than    the   Diesel 
engine.  , 

(2)  Absence   of   cold    circulating    water   causing   large    temperature 
difference  and  trouble  with  cylinder  and  head  castings. 

(4)  Lower  compression  pressure. 

(5)  Absence  of  air-starting,   circulating  and   piston-cooling   system. 

(6)  Absence  of  exhaust  valves  and  gear. 

(7)  Increased  horsepower  for  a  given  bore  and  stroke. 

(8)  Possibility  of  overload  by  forcing  steam  boiler. 

(9)  Maneuvering  at  low  revolution  per  minute  is  possible. 

(10)  High   temperature   range   2000   to   150   degrees  F.    (Carnot   ef- 
ficiency). 

Trials  with  a  single  cylinder  two-cycle  Still  engine  were  carried  out 
during  1921  by  Scott's  Shipbuilding  &  Engineering  Company,  Greenock, 
Scotland.  Owing  to  the  fact  that  the  experimental  engine  had  only  one 
cylinder,  it  was  necessary  to  provide  a  small  auxiliary  high  pressure 
steam  cylinder,  the  lower  end  of  the  main  Still  cylinder  serving  as  a 
low  pressure  steam  cylinder.  In  an  actual  installation  where  several 
cylinders  are  used  the  lower  part  of  one  can  be  used  >as  a  high  pressure 
cylinder,  and  the  lower  part  of  another  as  a  low  pressure  cylinder,  thus 
obviating  the  use  of  an  auxiliary  cylinder.  All  the  auxiliaries,  except  the 
scavenging  air  pump,  were  driven  off  the  main  engine  in  these  trials. 

A  photograph  of  this  engine  is  shown  in  Fig.  2,  and  a  digrammatic 
view  showing  all  the  auxiliaries  in  Fig.  3. 

The  result  of  the  trials  of  this  engine  are  given  in  the  following 
table: 


DESCRIPTION  OF  DIESEL  ENGINES  359 

'   TRIALS  OF  22-INCH   BY  36-INCH  STILL  OIL  ENGINE'. 

Main  Still  cylinder — Stroke,  36  inches.  Bore,  22  inches.  Piston  rod, 
6^4  inches. 

Auxiliary  higlnpressure  cylinder — Stroke,  14  inches.   Bore,  22  inches. 

Over-         Full         Half 
load          load         load 

1.  Average  combustion  M.E.P.,  Ibs.  per  sq.  in.__  88.9           81.2  54.2 

2.  Average  steam  M.E.P.  referred  to  H.P.__ 4.43           3.80  1.26 

3.  Average  steam  M.E.P.  referred  to  L.P 7.36           6.23  3.60 

4.  Total  M.  E.  P 100.69         91.25  59.06 

5.  R.    P.    M 128.1  124.3  103 

6.  Steam  boiler  pressure,  Ibs.  per  sq.  in.  gauge__112  100  108 

7.  H.P.  receiver  pressure,  Ibs.  per  sq.  in.  gauge 75              57  23.5 

8.  L.P.  receiver  pressure,  Ibs.  per  sq.  in.  gauge__  11               5.5  0.4 

9.  Vacuum,   inches    Hg 28              27.5  26.6 

10.  Water  evaporated  per  hour,  Ibs 950  807  388 

11.  Scavenging  pressure,   inches  water 49              46  40 

12.  H.P.    for    scavenging 15.4           14.1  12.0 

13.  Combustion   I.H.P.   394  349  5  192.5 

14.  Total   I.H.P.    446  392  210 

15.  Engine  B.H.P.   384  343  174.5 

16.  Net  B.H.P.    (line  15— line  12) 368.6  329  162.5 

17.  Oil  per  hour,  Ibs 146.6  123.4  64.0 

18.  Oil  per  net  B.H.P.  per  hour .398           .375  .394 

19.  Efficiency  on  net  B.H.P.,  per  cent 35.5           37.7  35.8  . 

It  will  be  observed  that  the  fuel  consumption  at  full  load  is  0.376 
pounds  per  brake  horsepower,  which  is  about  10  per  cent  lower  than  the 
best  four-cycle  Diesel  practice  and  nearly  20  per  cent  better  than  the 
general  run  of  two-cycle  Diesel  engines. 

Claims  are  put  forward  that  the  Still  engine  weighs  less  and  occupies 
less  space  than  the  Diesel  engine.  The  gain  in  economy  of  between  10 
and  15  per  cent  for  this  single  cylinder  engine  is  highly  encouraging 
and  no  doubt  this  can  be  improved  upon  when  several  cylinders  are 
used.  At  first  thought  the  engine  appears  complicated,  but  it  must  be 
borne  in  mind  that  the  air-starting,  circulating  and  piston-cooling  sys- 
tems are  eliminated  and  the  small  boiler  employed  with  the  Still  engine 
would  generally  be  required  on  a  Diesel  ship. 


DESCRIPTION  OF  DIESEL  ENGINES 


Cross-Section  of  Still  Engine 

DEFINITION    OF   PARTS: 

1.  Combustion  Cylinder. 

2.  Reinforcing  Steel  Hoop. 

3.  Scavenging  'Blower. 

4.  Combustion  Exhaust  Pipe  Jacketed  by  Boiler  Water. 

5.  Exhaust  Generator. 

6.  Feed  Water  Heater. 

7.  Final  Combustion  Exhaust  to  Atmosphere. 

8.  Boiler. 

9.  Main  Steam  Pipe. 

10.  Steam  Inlet  and  Exhaust  Valves, 

11,  Steam  Cylinder, 


DESCRIPTION  OF  DIESEL  ENGINES  361 

12.  Steam  Exhaust  to  Condenser. 

13.  Condenser. 

14.  Suction  Pipe  to  Air  Pump. 

15.  Air  Pump. 

16.  Feed  Pump. 

17.  Delivery  Pipe  to  Feed  Heater. 

18.  Circulating  Water,  Boiler  to  Exhaust  Generator. 

19.  Circulating  Water,  Exhaust  Generator  to  Cylinder  Jacket. 

20.  Circulating  Water  and  Steam;  Jacket  to  Boiler. 

21.  Auxiliary  Oil  Burner. 

22.  Condenser  Circulating  Pump. 

23.  Oil  Fuel  Injection  Pump. 

24.  Oil  Fuel  Delivery  to  Injection  Valve. 

25.  Injection  Valve. 


THE    WASHINGTON-ESTEP    MARINE    DIESEL    ENGINE. 
Four-cycle  Construction.     Airless  Injection.     (Solid   Injection). 

The  Washington-Estep  Diesel  Engine  is  a  modern  type  of  Diesel,  fol- 
lowing the  design  of  medium  sized  power-producers  particularly  adapted 
for  smaller  crafts  or  for  use  as  auxiliary  machinery  aboard  ship.  While 
this  engine  being  built  for  marine  purpose,  the  numerous  novel  features 
which  this  design  embodies  makes  it  an  elegant  factor  for  stationary 
work.  We  will  define  the  special  features  of  this  latest  type  of  Diesel 
engine. 

The  engine  illustrated  in  figure  (a)  is  of  three-cylinder,  four-cycle 
construction.  Its  horsepower  rating  ranges  from  65  to  140  B.  H.  P.,  ac- 
cording to  the  specified  size  desired.  The  engine  has  a  normal  load  of 
100  B.  H.  P.  at  280  R.  P.  M.,  when  running  with  a  continued  M.  E.  P.  of 
85  Ibs.  per  square  inch.  From  tests  at  hand  it  performs  power  at  125 
B.  H.  P.  with  ease  and  up  to  140  B.  H.  P.  as  a  maximum. 

There  are  two  fuel-injection  valves  of  special  design  in  each  cylinder 
head,  and  an  individual  fuel  pump  supplies  each  pair  of  injectors  with 
fuel  for  every  cylinder.  A  governor  controls  the  fuel  at  all  speeds. 

The  designers  have  found  it  advisable  to  depart  from  the  usual  de- 
sign of  cylinders,  having  the  same  equipped  with  removable  liners  or 
bushings.  Ample  water  jacket  space  is  provided  causing  the  thermal 
efficiency  of  the  engine  to  be  brought  to  a  high  standard.  It  will  be  re- 
alized, in  comparing  this  engine  with  similar  types  of  equal  horsepower 
capacities,  that  the  revolution  performances  is  rather  high,  being  from 
210  to  350  revolutions  per  minute. 

For  marine  service,  where  the  average  speed  is  generally  up  to  120 
R.  P.  M.,  rarely  exceeding  200  R.  P.  M.,  an  engine  of  this  nature  must  be 
capable  to  withstand  the  high  thermal  increase.  All  provisioncy  to  guard 
against  this  excess  heat  temperature  have  been  made  by  the  designer  of 
tbjis  engine  to  insure  ample  lubrication.  A  double  system,  i.e.,  forced- 


362 


DESCRIPTION  OF  DIESEL  ENGINES 


teed  circulating  system  through  manifold  and  crankshaft  to  all  bearings 
and  crosshead  pins  ,have  been  found  imperative.  A  sump  pump  takes  the 
return  oil  from  the  crank  pits  through  strainer  to  auxiliary  filtering  and 
cooling  tank,  automatic  governed  pressure  pump  has  'been  provided  from 
this  tank  to  bearings.  A  10-feed  mechanical  oiler  of  the  Manzel  type 
furnishes  fresh  oil  for  cylinder  lubrication. 

The  engine  is  fitted  with  bronze  centrifugal  circulating  pumps  and 
stand-toy  bronze  plunger  pump  running  half  speed  from  cam  shaft,  which 
can  be  used  for  bilge  and  deck  service.  A  water  cooled  air  pump  to  sup- 
ply starting  air  at  150  Ib'S.  pressure  is  also  provided.  The  fuel  oil  service 
pump  is  mounted  on  forward  end  of  the  frame. 


W ashing ton-E step  Engine,  Port   Side   View 


As  eos-tumary  on  small  and  medium  sized  engines,  the  piston  is  of 
the  trunk  type,  convex  head,  strongly  ribbed  to  support  large  hardened 
steel  piston  pin.  The  piston  is  equipped  with  six  piston  rings  of  special 
type  for  this  service. 

A  commendable  feature  is  the  large  cam  shaft  which  is  mounted  in 
adjustable  removable  bearings,  fitted  with  hardened  steel  accurately 
machined  cams,  all  enclosed  running  in  oil,  driven  with  simple  bpur  gears 


DESCRIPTION  OF  DIESEL  ENGINES 


363 


of  large  diameter  and  ample  face.  The  idler  gear  is  bronze  and  running 
in  oil.  Compression  release  for  hand  turning  is  also  provided. 

The  reverse  gear  is  of  a  patented  design  by  the  builders  of  this 
engine.  It  is  of  heavy  duty  type,  positive,  simple,  accessible  and  can  be 
backed  for  hours  without  heating.  The  clutch  is  the  latest  multiple  disc 
type  enclosed,  all  gears  are  heavy  simple  spur  type  cut  from  high  car- 
bon forgings.  The  entire  assembly  can  be  quickly  removed  from  engine 
by  letting  go  the  shaft  coupling  at  each  end. 

The  starting  can  be  accomplished  from  cold,  a  simple  water-cooled 
air  compressor  being  mounted  at  the  after  end  of  the  engine  for  the  pur- 
pose of  charging  starting-air  tanks  at  150'  Ibs.  pressure.  The  compression 
of  the  engine  is  limited  to  350  Ibs.,  being  of  similar  figure  to  most  'solid 
injection  types  of  engines  of  this  capacity. 


Washington-Estep  Engine,  Starboard  Side  View 


It  will  be  mentioned  here  that  instead  of  the  high  pump  pressure 
usually  adopted  with,  airless  injection,  or  direct  or  sometimes  called  solid 
injection,  the  designer  has  found  it  feasible  to  use  a  comparatively  low 
pressure  of  1,500  Ibs. 

The  thrust  bearing  is  of  the  removable  type  and  is  totally  enclosed, 
water-cooled,  and  provided  with  a  mechanical  oiling  system.  All  bear- 
ings are  removable. 

The  high-economy  establishment  of  this  engine,  brings  it  within 
reach  of  very  limited  operating  expenditure.  The  engine  will  consume 


364 


DESCRIPTION  OP  DIESEL  ENGINES 


Washington-Estep  Engine,  Showing  Engine-frame  and  Cylinder    Construction 


Estep  Design  of  Cylinders  and  Liners 


DESCRIPTION  OF  DIESEL  ENGINES  365 

5l/2  gallons  of  average  calorific  value  of  fuels  at  a  co<st  of  63  cents  per 
gallon,  in  addition  to  1/10  gallon  of  lubricating  oil  at  40  cents  per  gallon. 
The  total  expenditure  of  operating  the  engine  is  37  cents  per  hour,  which 
compares  with  considerable  over  $2.00  per  hour  for  engines  operated  by 
distillate  or  other  high  volatile  fuels. 


WASHINGTON-ESTEP    MARINE    DIESEL    ENGINES 
Four-Cycle,  Full  Diesel  Direct  Injection,  350  Ibs.  Compression. 

8-}4"Xl2"  at  350  R.P.M.  =  23.9  B.H.P.  per  Cylinder. 

107%  Stroke  ratio  700  feet  Piston  Speed. 

Approximate  weight  200  Ibs.  per  H.P. 

2  Cylinder    45  B.  H.  P.,  Weight     9,000  Ibs. 

3  Cylinder    70  B.  H.  P.,  Weight  13,400  Ibs. 

4  Cylinder    90  <B.  H.  P.,  Weight  18,000  Ibs. 
6  Cylinder  135  B.  H.  P.,  Weight  27,000  Ibs. 

5-inch  Crankshaft. 

10.)4"X16"  at  280  R.  P.  M.  —  38.5  B.  H.  P.  per  Cylinder. 

145%  Stroke  ratio,  746  feet  Piston  Speed. 

Approximate  Weight  230  Ibs.  per  H.P. 

3  Cylinder  110  B.  H.  P.,  Weight  25,200  Ibs. 

4  Cylinder  150  B.  H.  P.,  Weight  34,500  Ibs. 
*6  Cylinder  230  B.  H.  P.,  Weight  53,000  Ibs. 

6% -inch  Crankshaft. 


(*Dlrect  Reversible  Type.) 

16V2"X24"  at  210  R.  P.  M.  =  102  B.  H.  P.  per  Cylinder. 

149%  Stroke  ratio,  840  Piston  Speed. 

Approximate  Weight  230  l>bs.  per  B.H.P. 

*3  Cylinler  300  B.  H.  P.,  Weight    69,000  Ibs. 

*4  Cylinder  400  B.  H.  P.,  Weight    92,000  Ibs. 

*6  Cylinder  600  B.  H.  P.,  Weight  138,000  Ibs. 

Crankshaft, 


(* Direct  Reversible  Type.) 


366  DESCRIPTION  OF  DIESEL  ENGINES 

DIESEL    ENGINES    FOR    SUBMERSIBLE    CRAFTS. 

That  the  Diesel  engine  has  been  found  to  answer  the  requirements 
necessary  as  a  prime  mover  suitable  for  naval  duties  on  submersible 
crafts  has  been  fully  proven.  For  many  years  the  gasoline  driven  engine 
was  the  best  at  our  disposal,  but  as  gasoline  is  a  bad  thing  to  handle 
in  the -confined  space  of  a  submarine,  the  Diesel  engine  rapidly  sub- 
stituted the  gasoline  engine  as  soon  as  the  advantages  were  known  to 
governments  throughout  the  world.  The  development  of  these  engines 
was  quite  advanced  in  Germany  before  any  such  marine  engines  were 
built  in  this  country.  In  order  that  we  might  advance  as  rapidly  as 
possible,  all  known  engines  of  this  type  were  examined  by  our  engineers, 
and  the  conclusion  reached  that  the  engine  built  in  Nuremburg  was 
the  best  then  developed.  Steps  were  immediately  taken  to  acquire  the 
rights  for  this  country,  and  we  were  thus  able  to  get  for  our  submarines 
the  best  engine  then  developed.  Many  of  these  engines  were  built  and 
are  now  in  operation  in.  our  submarines.  In  the  building  and  operation 
of  these  engines  many  things  were  found  unsuitable  for  service  in  the 
United  States,  the  principal  reason  was  their  complication  of  mechanism. 
In  consequence  a  new  engine  was  designed — illustrated  in  Fig.  1.  -Other 
models  also  were  soon  brought  before  the  Bureau  of  Navigation,  and  it 
must  be  acknowledged  that  the  United  States  Government  has  much 
stimulated  and  encouraged  the  development  of  Diesel  machinery.  En- 
gines built  for  submarine  service  must  be  rigid  in  construction,  excellent 
in  workmanship,  reliable  in  action,  capable  to  stand  every  known  abuse, 
and  above  all,  accessible  for  inspection.  The  change  from  gasoline  to 
heavy  oil  has  brought  out  one  very  interesting  characteristic,  that  is, 
that  with  a  given  quantity  of  heavy  oil,  twice  the  number  of  horsepower- 
hours  may  be  obtained  as  from  a  like  quantity  of  gasoline.  Thus,  with 
a  boat  having  a  given  full  tank  capacity,  double  the!  radius  of  action  is 
obtained  when  the  change  from  gasoline  to  oil  is  made.  Another  point  is 
that  heavy  oil  costs  about  one-fifth  as  much  per  gallon  as  gasoMne; 
thus  for  a  given  number  of  horsepower-hours  the  fuel  of  the  Diesel 
engine  costs  about  one-tenth  that  for  the  gasoline  engine. 

Figure  2  gives  a  good  idea  of  the  mass  of  equipment  of  a  submarine, 
every  part  of  the  space  being  utilized.  The  picture  is  taken  from  amid- 
ship  looking  forward.  In  the  center  of  the  picture  is  shown  the  hand 
steering  wheel.  In  general  the  steering  is  done  by  electric  motor,  shown 
at  the  top  of  the  picture.  On  the  left  is  the  air  manifold,  with  valves 
for  control  of  the  high-pressure  air.  These  valves  connect  the  air  to  all 
the  different  tanks.  By  opening  the  valves  to  the  main  ballast  tanks 
the  water  may  be  blown  out  in  a  short  period  of  time.  On  the  right 
is  shown  the  water  manifold  which  connects  the  different  tanks  to  the 
adjusting  pumps,  also  the  levers  of  the  large  Kingston  valves.  Figure  3 
gives  a  view  looking  aft  from  amidships  and  showing  the  main  motors 
and  engines. 


DESCRIPTION  OP  DIESEL  ENGINES 


367 


368  DESCRIPTION  OP  DIESEL  ENGINES 

It  becomes  necessary  here  to  mention  the  Automatic  Blow  Valve. 
This  valve  connects  the  high-pressure  air  line  with  the  main  ballast 
tanks,  and  the  control  of  the  valve  is  by  diaphragm  in  connection  with 
the  outside  sea  water.  Thus,  if  the  pressure  reaches  too  high  a  figure, 
the  high-pressure  air  is  automatically  turned  into  the  main  ballast  tanks. 
These  tanks  tare  entirely  filled  with  water,  whenever  any  is  there,  and 
therefore,  at  such  times  the  main  Kingston  valves  are  left  open.  The 
turning  of  the  high-pressure  air  into  these  tanks  is  all  the  operation 
required  to  empty  the  tanks.  In  the  test  the  automatic  blow  valve  is 
set  to  some  depth,  say  50  ft.,  and  the  boat  allowed  slowly  to  sink. 
When  this  depth  is  reached  the  pressure  outside  operates  the  valve 
and  some  75  tons  of  water  are  quickly  blown  out  of  the  tanks.  The 
boat  immediately  starts  to  rise,  and  in  less  than  one  minute  will  reach 
the  surface,  nearly  jumping  out  of  the  water  from  the  rapid  rise.  The 
automatic  blow  valve  may  be  set  for  any  depth  that  may  be  desired. 


DESCRIPTION  OF  DIESEL  ENGINES 


SCO 


370 


DESCRIPTION  OP  DIESEL  ENGINES 


DESCRIPTION  OF  DIESEL  ENGINES 


371 


fe! 


m 


CHAPTER  XL 

DIESEL   ELECTRIC    PROPULSION. 

*DETAILED     INFORMATION     AND     OPERATING     INSTRUCTION     OF 

WESTINGHOUSE    ELECTRIC    MFGR.    CO.'S 

DIESEL-ELECTRIC  SYSTEM. 

Diesel  Electric  System  for  Ship  Propulsion:  Although  the  Diesel 
electric  system,  of  ship  propulsion  is  relatively  new,  the  constituent  parts 
making  up  the  system  are  well  established.  A  Diesel  electric  system 
preferably  consists  of  two  or  more  Diesel  engine  driven  generators 
furnishing  power  to  a  motor  driven  propeller.  The  ship  may  be  of  the 
single,  twin  or  multiple  'screw  type.  By  using  two  or  more  generating 
units  for  a  propeller,  definite  advantages  in  the  way  of  weight,  flexibility, 
control,  reliability,  etc.,  as  discussed  below,  are  readily  obtained.  The 
simplicity  of  the  Diesel  electric  system  is  obvious  when  it  is  realized 
that  the  (principal  component  parts  comprise  only  four  pieces  of  ap- 
paratus, such  as  Diesel  engines,  generators,  motors  and  control,  two  of 
which  are  quite  similar. 

Selection  of  Power:  In  selecting  the  power  for  a  Diesel  electric 
system,  we  have  a  choice  between  alternating  current  and  direct  cur- 
rent. For  the  reason  that  direct  current  obviates  operating  difficulties 
ensuing  from  alternating  current  parallel  operation;  eliminates  changes 
in  engine  speed;  adds  enormously  to  the  simplicity,  refinement  and 
economy  of  control;  and  provides  greater  power  in  case  of  casualty  to 
a  generating  unit,  the  direct  current  system  is  obviously  the  proper  sys- 
tem to  use.  In  cases  where  a  single  generator  supplies  power  to  a 
single  motor,  alternating  current  could  be  used  without  encountering 
difficulties  ensuing  from  parallel  operation,  but  such  a  system  would  be 
far  Inferior  to  the  direct  current  system  in  flexibility,  reserve  power 
and  control.  Furthermore,  a  multiplicity  of  generating  units,  as  are 
used  inj  the  case  of  D.  C.  systems,  adds  considerably  to  the  ultimate  re- 
liability. Therefore,  in  the  large  majority  of  cases,  Diesel  electric  sys- 
tems will  utilize  direct  current. 

In  the  case  of  direct  current  systems,  there  are  two  general  ar- 
rangements of  machine  connections  that  suggest  themselves.  One  ar- 
rangement is  to  operate  the  generators  in  parallel,  and  control  the  motor 
speed  and  maneuvering  by  armature  rheostatic  means.  This  system, 

*Specially   Prepared   by   W.   E.   Thau,   Marine   Engineer. 
Copyright  by  Westinghouse  Electric  &  Mfgr.  Co. 


374  DIESEL  ELECTRIC  PROPULSION 

however,  is  rather  cumbersome,  wasteful  during  maneuvers  and  speed' 
changes,  and  necessitates  a  complicated  controller.  The  other  employs 
what  is  known  as  the  voltage  control?  or  Ward  Leonard  control  system. 
With  this  system,  -pure  shunt  machines  are  used  and  both  motors  and 
generators  are  separately  excited,  preferably  from  the  same  source. 
The  motor  fields  are  excited  at  constant  potential,  and  always  in  the 
same  direction.  The  excitation  of  the  generator  fields  is  varied  to  suit 
the  motor  speed  and  direction  of  rotation  desired.  By  varying  the  volt- 
age applied  to  the  armature  terminals  of  a  shunt  motor,  having  a  con- 
stant field  excitation,  the  motor  speed  can  be  varied  in  direct  proportion, 
both  as  regards  speed  value  and  speed  direction;  and  since  the  voltage 
generated  by  a  constant  speed,  separately  excited,  shunt  wound  gener- 
ator is  directly  proportional  to  its  field  excitation  (neglecting  saturation), 
the  motor  speed  is,  in  turn,  .proportional  to  the  generator  excitation. 
With  such  an  arrangement,  therefore,  it  is  only  required  to  vary  the  gen- 
erator fields  from  full  excitation  in  one  direction  to  full  excitation  in 
the  opposite  direction,  to  cause  the  motor  to  maneuver  from  full  speed 
ahead  to  full  speed  astern.  To  further  simplify  this  method  of  control, 
all  machines  are  connected  in  series.  With  the  series  connection,  it  is 
unnecessary  to  maintain  like  speeds  on  all  the  engines.  Provided  the 
generators  are  excited  equal  amounts  and  have  identical  performance, 
the  only  effect  of  difference  in  engine  speeds  is  a  proportional  difference 
in  the  loads  carried  by  the  generators,  and  their  driving  engines.  From 
an  operating  standpoint,  therefore,  the  series  system  is  ideal,  and  per- 
mits/by far  the  simplest  system.  Parallel  operation  of  generators  with 
the  Ward-Leonard  system  would  be  very  difficult,  in  fact,  almost  im- 
practical. 

Since  it  is  only  necessary  to  handle  the  generator  field  excitation 
currents  for  maneuvering  the  ship  from  full  speed  ahead  to  full  speed 
astern,  or  holding  any  particular  desired  speed,  the  economy  of  the 
Ward-Leonard  system  is  obviously  superior  to  that  of  the  armature 
rheostatic  system  during  any  other  than  lull  speed  operation,  for  the 
reason  that  the  generator  field  excitation  power  does  not  exceed  \l/2% 
of  the  total  output  of  the  generator.  Dealing  with  these  small  currents, 
the  control  is  extremely  simple  and  inexpensive.  This  simplicity  has  a 
further  direct  effect  on  the  maintenance  of  the  equipment. 


BRIEF   DESCRIPTION   OF   UNITS: 

Engines:  The  engine  used  with  Diesel  electric  propulsion  may  be 
any  reliable  make  of  Diesel  engine,  which  operates  at  a  reasonably  high 
rotative  speed.  The  term  "rotative  speed"  is  used  instead  of  "speed" 
to  distinguish  from  high  piston  speeds.  Many  people  associate  the  en- 
gines used  with  Diesel  electric  propulsion  with  those  used  for  sub- 
marine propulsion.  Diesel  engines  which  are  properly  designed  for  use 
with  Diesel  electric  propulsion  need  not  exceed  established  safe  piston 
speeds  for  continuous  operating  engines.  By  using  many  cylinders  of 


DIESEL  ELECTRIC  PROPULSION  375 

short  stroke  and  small  bore,  the  heat  stresses  common  to  large  cylinder, 
slow  speed  engines  are  minimized,  and  the  result  should  be  an  engine 
requiring  less  maintenance,  and  an  engine  of  simpler  construction. 

By  resorting  to  higher  rotative  speed  engines,  it  is  well  known  that 
the  weight  per  brake  horsepower  can  be  brought  down  very  rapidly. 
This  characteristic  is  an  important  one  in  connection  with  Diesel  elec- 
tric drive,  as  the  amount  of  weight  thus  saved  in  the  engine  is  consid- 
erably more  than  that  added  by  the  electrical  machinery,  and  hence  re- 
sults in  a  total  machinery  installation  which  is  lighter  than  that  of  any 
other  type.  It  is  confidently  anticipated  that  the  weight  of  a  Diesel 
electric  propulsive  installation  using  properly  designed  engines,  should 
be  approximately  ^  that  of  a  twin  screw  direct  connected  Diesel  pro- 
pulsive system,  and  in  the  neighborhood  of  75%  of  the  weight  of  an 
economical,  geared-turbine  'propulsive  equipment. 

Generators:  The  generators  used  with  the  preferable  form  of  Diesel 
electric  propulsion  are  simple,  direct  current,  shunt  machines,  the  con- 
struction and  performance  of  which  are  easily  comprehended  by  any 
person  having  a  mechanical  turn  of  mind.  These  machines  consist  es- 
sentially of  two  parts,  the  field  or  stationary  element,  and  the  armature 
or  rotating  element. 

The  field  is  made  up  of  a  cylindrical  steel  ring,  split  at  the  horizontal 
center  line  for  convenience,  and  having  an  elliptical  section.  Electrically, 
this  frame  serves  to  carry  the  field  flux,  and  mechanically  to  support  the 
field  poles.  The  frame  is  machined  on  the  inside  diameter  in  order  to 
form  a  true  seat  for  the  field  ipoles  which  are  bolted  to  it  and  symmetri- 
cally spaced.  The  main  field  poles  are  composed  of  a  number  of  die- 
punched  laminations  of  sheet  iron,  which  are  riveted  together  to  form  a 
solid  pole.  The  commutating  field  poles  are  built  of  solid  steel  and  lo- 
cated between  the  main  poles. 

The  main  field  coils  which  produce  the  field  flux  consist  of  a,  large 
number  of  turns  of  insulated  copper  wire  having  a  relatively  small  sec- 
tion. The  coil  is  wound  on  a  form,  slipped  on  the  field  poles  before  they 
are  bolted  to  the  frame,  and  rigidly  supported  from  these  field  poles  by 
insulated  supports.  These  coils  are  known  as  shunt  coils,  and  are  con- 
nected in  series. 

The  winding  for  the  commutating  field  pole  consists  of  a  relatively 
small  number  of  turns  of  bare  copper  strap  secured  by  insulated  sup- 
ports. This  winding  is  connected  in  series  with  the  armature,  and  car- 
ries the  line  current.  The  purpose  of  the  commutating  pole  winding  is  to 
provide  a  magnetic  field  to  neutralize  the  effect  of  the  current  reversal 
in  the  armature  coils  undergoing  commutation,  .and  thus  to  effect  spark' 
less  commutation.  Since  the  commutating  field  winding  is  in  series  with 
the  armature,  and  carries  the  same  current,  the  correct  amount  of  com- 
mutating pole  flux  is  automatically  provided  under  all  conditions  of  load 
within  the  capacity  of  the  machine. 

The  armature  consists  essentially  of  a  cylindrical  core  built  up  of 
steel  laminations  which  are  dovetailed  and  secured  to  a  cast  spider,  the 


376  DIESEL  ELECTRIC  PROPULSION 

spider  in  turn  being  pressed  and  keyed  on  to  the  shaft.  The  steel  lam- 
inations are  provided  with  teeth  punched  in  their  periphery,  and  into 
which  the  armature  coils  are  placed. 

The  commutator  to  which  the  armature  coils  are  connected  is  made 
up  of  a  series  of  hard  drawn  copper  bars  securely  Insulated  from  one 
another  by  means  of  mica  insulation.  These  commutator  bars  are  built 
up  on  a  separate  spider  and  securely  fastened  thereto  by  means  of  "V" 
rings  fitting  into  insulated  machined  recesses  in  the  bars,  or  by  some 
other  suitable  means.  The  commutator  spider  is  then  pressed  on  an  ex- 
tension of  the  armature  spider,  or  directly  on  the  shaft  and  keyed 
thereto. 

The  armature  coils  are  form  wound  and  completely  insulated  and 
treated  so  as  to  be  moisture  resistant,  before  they  are  placed  in  the  slots, 
and  connected  to  their  respective  commutator  bars.  The  armature  coils 
for  any  given  machine  are  identical. 

The  armature  is  usually  carried  on  a  forged  steel  shaft  having  an 
integral  flange  at  one  end  which  is  bolted  directly  to  the  flywheel  of  the 
engine,  the  other  end  being  carried  by  a  pedestal  type  bearing. 

The  brush  rigging  which  properly  constitutes  a  part  of  the  stationary 
member,  serves  to  collect  the  current  from  the  commutator,  and  is  sup- 
ported from  the  field  frame.  There  are  the  same  number  of  brush  arms 
as  main  field  poles.  Brush  arms  are  symmetrically  placed  and  so  located 
that  the  brushes  rest  on  commutator  bars  which  connect  to  armature 
coils,  which  lie  in  the  commutating  zone,  which  in  a  commutating  pole 
machine  is  midway  between  the  main  field  poles. 

The  brush  arms  carry  a  series  of  brush  holders,  each  of  which  is 
provided  with  a  carbon  brush  connected  to  the  brush  holder  by  means  of 
a  copper  shunt  (sometimes  called  a  pig-tail).  To  insure  an  equal  dis- 
tribution of  current  in  the  brushes,  an  adjustable  spring  is  provided  on 
each  brush  holder  which  maintains  the  pressure  of  the  carbon  brush  on 
the  commutator  at  a  given  predetermined  correct  value. 

Motors:  The  corresponding  description  of  the  motor  is  identically 
the  same  as  that  of  the  generator,  and  therefore,  will  not  be  given.  In 
order  to  minimize  the  total  weight,  it  is  preferable  to  provide  the  motor 
without  a  bedplate,  and  simply  to  provide  feet  on  the  field  frames  and 
bearing  pedestals  suitable  for  mounting  on  a  built-up  structural  steel 
bedplate  in  the  ship.  The  structure  supporting  the  motor  should  be 
rigid  so  as  to  avoid  distortion^ 

The  bearings  of  the  generators  are  usually  supplied  with  lubrication 
from  the  engine  lubricating  system.  In  the  case  of  the  motors,  it  is  usual 
to  provide  oil  ring  lubrication.  In  some  cases,  however,  forced  or  flood 
lubrication  is  provided,  the  oil  being  supplied  by  a  gear  pump  actuated 
from  the  motor  shaft. 

Exciter  Arrangements:  The  exciters  for  the  generator  and  motor 
fields  may  either  be  driven  by  the  main  engines,  or  by  separate  engines. 
In  either  case,  they  may  furnish  power  to  the  auxiliaries  in  addition  to 
that  for  excitation. 


DIESEL  ELECTRIC  PROPULSION  377 

If  driven  by  the  main  engines,  the  exciters  should  be  direct  con- 
nected to  the  main  generator  either  by  means  of  a  coupling,  or  by 
mounting  on  an  extension  of  the  generator  shaft.  In  the  latter  arrange- 
ment, the  exciter  armature  may  be  overhung  if  the  mechanical  factors 
permit.  Driving  the  exciters  from  the  main  generator  shafts  by  means 
of  chains,  belts  or  gears,  effects  a  slight  saving  in  weight  and  overall 
length  of  the  set,  however,  it  is  not  nearly  as  satisfactory  mechanically 
as  direct  drive. 

Whether  it  is  best  to  use  direct  driven,  or  separately  driven  exciters, 
depends  upon  such  factors  as  sea  load,  desired  flexibility,  capacity  of 
main  generators  as  related  to  port  demands,  available  space,  etc.,  and 
each  case  must  be  considered  on  its  merits.  When  the  arrangement  is 
convenient,  it  is  usually  preferable,  however,  to  drive  the  exciters  by  the 
main  engines,  as  it  results  in  a  self-contained  propulsive  plant. 

Control:  The  control  consists  of  a  suitable  switchboard  containing 
the  necessary  switches  for  the  several  machines  involved,  the  instru- 
ments, protective  relays,  circuit  breaker,  etc.;  a  special  reversing  field 
rheostat  for  the  generator  field  circuits;  and  a  manually  operated,  re- 
mote control  mechaniam,  preferably  mounted  on  a  pedestal  for  operat- 
ing the  field  rheostat. 

There  are  two  general  methods  of  operating  the  field  rheostat.  One 
method  employs  a  handle  which  operates  in  the  fore  and!  aft  direction, 
and  is  thus  similar  to  present  steam  engine  control.  This  handle  operates 
the  rheostat  through  a  system  of  rods  and  bevel  gears.  The  other  sys- 
tem employs  a  worm  and  wheel  instead  of  the  handle,  and  is  preferable 
to  the  handle  for  the  reason  that  it  provides  an  inherent  time  element 
in  that  it  requires  a  certain  definite  time  to  actuate  it  from  full  ahead  to 
stop,  and  full  astern  positions.  This  time  element  is  essential,  as  too 
rapid  change  in  the  field  strength,  would  cause  serious  overloads  on  the 
machinery.  It  has  been  found  from  actual  service  that  the  minimum 
time  which  would  be  consumed  in  bringing  the  propellers  from  full 
speed  ahead  to  the  stopped  condition  is  approximately  5  seconds,  and 
by  designing  the  worm  and  wheel  so  that  it  would  require  5  seconds 
to  make  the  number  of  turns  necessary  for  full  speed  to  stop  position, 
this  required  time  element  is  automatically  provided.  With  the  lever 
operation,  it  is  possible  to  move  the  control  instantly  to  the  off  position, 
and  thereby  cause  a  large  rush  of  current. 

The  switches  for  the  machines  are  so  arranged  that  any  particular 
generator  or  motor  unit  may  be  taken  out  of  service  by  simply  throwing 
its  switch  from  one  position  to  another.  This  operation  is  usually  ef- 
fected without  interrupting  the  service  to  the  propeller  motor. 

A  more  detailed  description  of  the  control  is  given  below  in  the  case 
of  a  specific  example, 


378  DIESEL  ELECTRIC  PROPULSION 

ADVANTAGES: 

The  advantages  of  Diesel  electric  propulsion  as  compared  with  any 
form  of  steam  drive  are  very  pronounced. 

Fuel  Economy:  The  most  important  advantage  is  that  resulting 
from  the  difference  of  fuel  economy.  A  properly  designed  Diesel  electric 
propulsive  equipment  requires  about  0.55  Ibs.  of  oil  per  shaft  horsepower 
hour  for  all  purposes,  whereas  the  average  high  grade  steam  installation 
requires  about  twice  this  amount,  or  more.  The  saving  in  fuel  is  of  two- 
fold importance  First,  the  actual  difference  in  fuel  cost,  and  second,  the 
additional  cargo  that  can  be  carried  due  to  the  decreased  weight  of  fuel, 
or  the  greater  cruising  radius  for  a  given  amount  of  fuel  oil. 

Weight:  A  proper  Diesel  electric  propulsive  equipment  being  lighter 
than  the  geared  turbine  equipment  of  high  grade  performance,  enables 
additional  cargo  to  be  carried  in  the  amount  of  the  weight  difference. 
The  importance  of  this  feature  is  apparent  as  it  affects  the  ultimate 
earning  ability  of  the  ship. 

As  compared  with  a  direct  connected  twin  screw  Diesel  drive,  the 
Diesel  electric  is  about  on  a  parity  in  regard  to  fuel  consumption,  but 
considerably  lighter  in  weight. 

The  direct  drive  Diesel  has  demonstrated  its  superior  economy  in 
the  earning  power  of  the  ship  as  compared  with  the  steam  drive.  The 
result  was  accomplished  in,  spite  of  the  excess  machinery  weight  of  the 
former  as  compared  with  the  latter.  Similarly,  as  the  Diesel  electric  is 
considerably  lighter  than  the  direct  drive  Diesel,  the  Diesel  electric  will 
show  superior  earning  power  as  compared  with  the  direct  drive  Diesel, 
particularly  on  long  runs. 

Reliability  and  Reserve  Power:  By  providing  a  number  of  small 
generating  units,  the  reliability  of  the  Diesel  electric  drive  is  superior 
to  that  of  the  direct  connected  Diesel  drive,  both  from  the  standpoint  of 
individual  engines,  and  the  drive  collectively,  in  the  case  of  casualty. 
This  superiority  of  the  Diesel  electric  also  obtains  when  compared  with 
the  steam  drive. 

Reserve  power  in  case  of  casualty  to  any  of  the  generating  units  is 
important.  Having  a  number  of  generating  units,  the  reliability  in  case 
of  casualty  is  infinitely  greater  than  in  the  case  of  a  single  screw  steam- 
ship. Although  with  a  cross  compound  geared  turbine,  the  failure  of  one 
element  would  still  enable  operation  at  about  50%  power  from  the  re- 
maining element,  it  would  be  at  a  sacrifice  of  considerable  speed  and 
economy.  A  similar  analysis  applies  in  the  case  of  the  twin  screw  direct 
connected  Diesel.  To  provide  a  motor  of  small  diameter  it  is  customary 
to  use  what  is  known  as  a  double  unit  motor  which,  incidentally,  results 
in  greater  reserve  power  flexibility.  The  double  unit  motor  essentially 
consists  of  two  electrically  independent  motors  mounted  on  the  same 
shaft.  With  such  an  arrangement,  the  reliability  and  reserve  power  of 
the  Diesel  electric  in  case  of  casualty,  is  infinitely  superior  to  that  of 
the  single  turbine  and  single  direct  drive  Diesel  single-screw  ship. 


DIKSE'L  ELECTRIC  PROPULSION  379 

With  the  Ward-Leonard  system,  using  the  series  arrangement  of 
machines,  more  reserve  power  is  available  in  case  of  casualty  to  a  prime 
mover  than  is  the  ease  with  any  other  system  of  ship  propulsion.  Tak- 
ing, for  example,  a  3-generator,  single-screw  arrangement,  the  failure  of 
one  generating  unit  would  enable  88%  speed  to  be  obtained  with  the  re- 
maining two  sets,  and  in  the  case  of  the  failure  of  two  generating  sets, 
the  single  remaining  set  would  furnish  sufficient  power  to  propel  the 
ship  at  70%  speed.  This  analysis  is  'based  on  the  driving  power  varying 
as  the  cube  of  the  speed.  This  system  is  in  fact  the  only  system  that 
permits  full  power  to  'be  derived  from  remaining  units  without  overload- 
ing them,  or  increasing  the  original  size  and  weight. 

To  obtain  the  full  capacity  of  the  remaining  units  under  conditions 
stated  in  the  foregoing  paragraph,  it  is  merely  necessary  to  set  each 
generator  for  its  full  rated  voltage,  and  then  to  decrease  the  motor  field 
current  until  full  load  armature  current  flows  through  the  system.  In 
the  example  cited,  full  load  current  with  two  generators  in  operation 
would  supply  two-thirds  of  the  total  power,  and  with  one  generator  in 
operation,  would  supply  one-third  full  power.  It  is  necessary  to  weaken 
the  motor  field  to  obtain  the  required  speed  for  the  remaining  power,  as 
otherwise  the  motor  would  operate  at  a  speed  directly  proportional  to 
the  total  remaining  generator  voltage.  If  the  motor  is  of  the  single 
armature  type,  its  field  flux  would  be  reduced  to  76%  to  obtain  88% 
speed  with  two  generators  in  operation;  and  47^%  with  one  generator 
in  operation.  If  the  motor  is  of,  the  double  unit  type  with  its  armatures 
normally  operated  in  series,  70%  speed  can  'be  obtained  with  one  gen- 
erator, and  one  motor  unit,  and  in  this  case  this  motor  field  flux  is  re- 
duced to  about  95%  of  full  value. 

In  the  case  of  a  twin  or  multiple  screw  ship  having  Diesel  electric 
propulsion,  a  casualty  to  a  prime  mover  does  not  prevent  supplying  bal- 
anced power  to  all  screws.  The  switching  is  so  arranged  that  the  gen- 
erators may  be  connected  to  any  of  the  motors.  This  is  of  further  ad- 
vantage in  that  the  remaining  prime  movers  are  operated  under  normal 
power  conditions  and  consequently  normal  efficiency. 

Recalling  the  reliability  which  was  discussed  above,  it  is  incon- 
ceivable to  imagine  a  reasonable  condition  of  casualty  in  the  case  of 
Diesel  electric  propulsion  that  would  prevent  the  ship  from  reaching 
port  at  a  reasonable  speed. 

Simplicity:  The  characteristics  of  the  engine  for  Diesel  electric 
drive  are  constant  speed  and  reasonably  close  regulation  from  no  load 
to  full  load.  iSince  the  engines  operate  at  constant  speed  and  always  in 
one  direction,  it  is  unnecessary  to  point  out  the  elimination  of  the  re- 
versing gear,  as  well  as  the  air  for  reversing.  The  result  of  the  elimina- 
tion of  these  two  features  means  a  simpler  and  probably  a  more  reliable 
engine.  It  at  least  reduces  the  air  problems  to  their  simplest  terms. 
Air  is  used  only  for  the  initial  start  in  port.  In  fact,  the  plant  can  be 
arranged  so  that  only  one  engine  need  be  started  by  air  and  subsequent 
engines  started  electrically  by  utilizing  their  generators  as  motors. 


380  DIESEL  ELECTRIC  PROPULSION 

Furthermore,  as  an  extreme  arrangement,  starting  air  may  be  eliminated 
entirely  by  providing  a  .small  gasoline  or  kerosene  engine  generator  set 
to  do  the  starting  of  the  main  engines  electrically. 

Stand-by  Conditions:  Since  the  Diesel  engine  consumes  fuel  only 
when  running,  a  further  economy  is  effected  by  the  elimination  of  stand- 
by losses.  Also,  it  is  unnecessary  to  warm  up  various  pieces  of  machin- 
ery, such  as  boilers,  turbines,  etc.,  for  a  long  period  prior  to  "getting 
under  way."  The  Diesel  electric  system  can  be  made  ready  for  sailing 
on  short  notice. 

Conclusion:  From  the  foregoing  discussion,  it  will  be  obvious  that 
the  Diesel  electric  system  of  ship  propulsion  using  series  connected 
D.  C.  machines  operating  on  the  Ward-Leonard  principle,  is  considerably 
more  than  a  mere  electric  coupling  or  gear.  It  is  a  system  containing 
very  pronounced  features  which  are  of  direct  advantage  to  the  improved 
performance  of  the  ship.  The  fact  that  the  electrical  machines  constitute 
a  reliable  'and  flexible  substitution  for  gears  and  magnetic  couplings  is 
merely  incidental. 

LIMITS  OF  CAPACITY: 

Based  on  present-day  available  Diesel  engines,  which  are  suitable 
for  Diesel  electric  drive,  the  capacity  limit  of  a  single  Diesel  electric 
drive,  is  approximately  7500  H.  P.  This  figure  could  be  increased  by 
using  an  unreasonably  large  number  of  engines.  Some  ultra-enthusiastic 
advocates  of  Diesel  electric  propulsion  have  entertained  the  idea  of  using 
as  many  as  18  engines.  However,  the  more  conservative  advocates  would 
limit  the  number  of  engines  for  a  single  installation  to  eight,  and  this 
only  as  an  extreme  measure.  The  preferable  number  of  engines  for  a 
single-screw  drive  is  three  or  four. 

Engines  of  1000  H.  P.  per  cylinder  are  now  being  seriously  consid- 
ered, and  in  fact,  developments  of  such  engines  are  already  under  way. 
Using  six  or  eight  cylinder  engines,  having  this  capacity  of  cylinder,  it 
is  easily  conceivable  that  single  installations  of  50,000  H.  P.  are  on  the 
horizon. 

With  possible  future  developments  in  Diesel  engines,  the  limit  may 
be  within  the  greatest  demand  for  a  single  drive.  As  Kipling  said, 
"Came  the  power  with  the  need." 


PERFORMANCE: 

Stopping  and  R-eversing:  Because  of  the  inherent  functioning  of  a 
Ward-Leonard  system  of  Diesel  electric  propulsion  it  is  necessary  to  give 
some  thought  to  the  inherent  characteristics  of  propeller  performance, 
particularly  quick  istopping  when  under  full  headway.  Turning  warrants 
consideration  only  in  the  case  of  multiple  screw  ships,  and  only  then  in 
particular  types  of  drive,  such  as  turbine-electric  using  alternating  cur- 
rent machinery. 


DIESEL  ELECTRIC  PROPULSION  381 

During  quick  stopping,  however,  it  is  necessary  to  overcome  the 
propeller  torque  in  order  to  bring  the  ipropeller  to  rest.  This  propeller 
torque  is  developed  by  reason  of  the  motion  of  the  ship  through  the 
water,  which  causes  the  propeller  to  be  driven  as  a  water  motor.  Al- 
though strict  analysis  of  this  performance  is  not  pertinent  to  the  pres- 
ent discussion,  it  is  well  to  recognize  the  results.  In  the  case  of  a  pure 
Ward-Leonard  system  of  Diesel  electric  propulsion,  the  principal  means 
of  absorbing  the  energy  returned  through  the  screw  is  the  friction  of  the 
engines.  If  more  energy  is  returned  than  can  be  dissipated  by  the  fric- 
tion losses  in  the  engines,  and  the  losses  of  transmission,  external  means 
such  as  dynamic  braking  resistors  must  be  provided.  If  all  the  energy 
returned  by  the  screw  is  not  dissipated  by  the  f Fictional  losses  of  the 
engines,  or  otherwise,  it  will  be  expended  in  increasing  the  speed  of  the 
engines.  Whether  or  not  the  increased  speed  would  be  detrimental  to 
the  engines  can  only  be  conjectured.  However,  it  is  confidently  be- 
lieved that  in  the  large  majority  of  cases,  and  particularly  those  of  the 
ordinary  cargo  ship,  that  this  energy  will  not  be  in  excess  of  that  which 
can  be  obsorbed  by  the  frictional  losses  of  the  engine.  Specific  tests  of 
this  performance  were  made  in  the  case  of  some  Diesel  electric  yachts 
when  stopping  from  full  speed,  and  it  was  found  that  there  were  no 
increases  in  the  engine  speeds  due  to  this  cause. 

A  conservative  analysis  shows  that  the  maximum  horsepower  re- 
turned to  the  engines  when  bringing  the  propellers  to  rest  from  full 
speed,  is  approximately  33%,  and  that  this  peak  value  will  last  for  a 
very  brief  instant  only.  The  average  horsepower  returned  is  approxi- 
mately 18%.  The  values  take  into  account  the  torque  produced  by  the 
propeller  and  the  inertia  forces  of  the  motor  armatures  and  the  pro- 
peller, based  on  a  stop  of  five  seconds.  Since  the  average  four-cycle 
engine  with  attached  auxiliaries)  is  approximately  75%  efficient,  and  the 
average  two-cycle  engine  with  attached  auxiliaries  is  approximately  72% 
efficient,  based  on  brake  horsepower,  it  is  apparent  that  the  frictional 
losses  in  either  case  amount  to  at  least  33%  of  the  engine  output.  There 
is  a  slight  margin  in  these  figures,  as  no  allowance  was  made  for  the 
propeller  shaft  bearing  friction.  Due  to  this  returned  energy  when  mak- 
ing quick  stops,  or  reversals,  it  is  necessary  to  design  the  engine  gov- 
ernors to  throttle  to  practically  zero  oil  flow,  in  order  that  the  friction 
losses  of  the  engine  may  provide  a  load  for  absorbing  the  returned 
energy. 

In  cases  where  the  compressors,  etc.,  are  separately  driven,  and  in 
cases  where  the  returned  energy  otherwise  is  in  excess  of  what  the 
engines  can  absorb,  it  is  necessary  to  connect  resistance  in  the  circuit 
during  quick  stops,  for  absorbing  the  excess.  This  is  very  easily  ar- 
ranged, and  its  insertion  is  done  automatically  by  an  auxiliary  circuit 
actuated  by  virtue  of  relative  position  or  motion  of  the  control  device. 

Turning:  When  turning  ait  full  power,  there  is  an  increase  in  the 
load  on  the  propellers.  This  increase  is  particularly  pronounced  in  the 
case  of  multiple  screw  ships,  as  the  power  builds  up  enormously,  especial- 
ly on  the  inboard  side  of  the  turn  if  means  are  not  taken  to  guard 


382  DIESEL  ELECTRIC  PROPULSION 

against  it.  This  characteristic  causes  some  concern  in  the  case  of  al- 
ternating current  drives,  and  necessitates  special  control  devices.  Eveii 
though  the  input  to  the  prime  mover  toe  limited  to  normal  running  value, 
there  is  a  drop  in  its  speed  and  an  increase  in  torque  of  approximately 
25%  to  30%.  Since  a  normal  Diesel  engine  has  very  little  overload 
capacity,  any  building  up  of  torque  will  cause  a  reduction  in  its  speed, 
and  therefore,  its  output  is  automatically  limited.  The  inherent  char^ 
acteristics  of  the  D.  C.  motors  and  generators  >are  such  that  they  will 
carry  the  increase  in  torque  without  the  least  danger  of  becoming  un- 
stable, and  hence  no  special  precautions  need  be  taken.  There  is  always 
a  stable  couple  between  the  generators  and  the  motors. 

Bridge  Control:  Since  the  engines  operate  at  practically  constant 
speed,  and  in  the  same  direction  at  all  times,  and  are  under  the  control 
o-f  a  constant  speed  governor,  they  require  no  attention  during  maneuver- 
ing. This  combined,  with  the  absence  of  such  factors  as  steam  pressure, 
boiler  fires,  priming,  etc.,  make  control  of  the  propeller  machinery  from 
a  remote  location  entirely  feasible.  In  other  words,  the  ship  is  controlled 
just  as  easily  from  the  bridge  as  from  the  engine  room.  The  importance 
of  such  performance  is  obvious  in  the  case  of  ships  requiring  very  ac- 
curate maneuvering  in  restricted  places,  as  it  eliminates  both  delay  in  re- 
sponse to  signals,  and  risk  as  a  consequence  of  mistaken  signals,  The 
Diesel  electric  system  is,  in  fact,  the  only  system  of  ship  propulsion 
that  affords  bridge  control  without  resorting  to  complications  which  are 
questionable  at  best. 

Torque  at  Low  Sp-eed:  In  regard  to  low  speed  torque,  the  Diesel 
electric  system  here  described  is  very  similar  to  the  turbine,  in  that  it 
is  capable  of  developing  large  overload  torque  at  reduced  speed:  Theo- 
retically, the  torque  at  the  motor  shaft  may  be  increased  in  inverse  ratio 
to  the  speed  without  overloading  the  engines.  However,  safe  commuta- 
tion of  the  electrical  machines  of  ordinary  design  places  a  practical 
limit  on  the  torque  that  can  be  developed  under  these  conditions.  For 
the  purpose  of  ship  drive,  however,  the  ordinary  direct  current  machine 
will  develop  sufficient  torque  to  meet  any  emergency. 

Special  Provisions:  A  few  special  precautions  are)  necessary.  Over- 
load protection  is  necessary  to  prevent  serious  injury  to  the  electrical 
machinery.  This  protection  is  provided  in  the  form  of  a  circuit  breaker 
whose  function  it  is  to  open  the  circuit  on  excessive  overloads.  Owing 
to  the  desirability  of  maintaining  continual  control  of  the  screw  under 
all  conditions,  the  adjustment  of  the  circuit  breaker  is  such  that  it  will 
not  open  under  any  normal  operating  conditions  of  the  ship.  The  idea 
in  providing  the  circuit  breaker  is  merely  to  provide  protection  to  the 
machinery  in  the  case  of  an  equivalent  of  a  short-circuit. 

Assuming  that  the  circuit  breaker  has  tripped  while  the  ship  is 
under  way,  and  it  is  desirable  to  immediately  regain  control  of  the 
screw,  it  is  necessary  to  first  establish  proper  voltage  conditions  on  both 
sides  of  the  circuit  breaker  before  the  circuit  breaker  can  be  closed. 


DIESEL  ELECTRIC  PROPULSION  383 

The  motor  will  generate  a  counter  voltage  due  to  the  fact  that  it  is  toe- 
ing rotated  by  the  action  of  the  propeller.  To  close  the  circuit  breaker 
without  jarring  the  machinery  or  producing  a  large  rush  of  current,  It 
is  necessary  that  the  generator  voltage  be  somewhere  near  that  of  the 
motor  voltage.  To  effect  the  closing  of  the  circuit  breaker  ait  the  proper 
instant,  voltage  balance  relays  are  provided,  the  function  of  which  is  to 
prevent  the  automatic  circuit  breaker  from  closing  until  the  voltages  on 
both  sides  of  its  contacts  are  approximately  the  same.  This  device  is 
automatic  and  is  described  below  in  the  case  of  a  specific  example. 

In  the  case  of  a  number  of  generators  connected  in  series,  the  fail- 
ure of  power  on  one  of  the  engines  would  result  in  that  generator 
stopping,  reversing  and  speeding  up  in  the  opposite  direction  as  a  motor, 
being  supplied  with  power  from  the  remaining  generating  sets.  The 
speed  which  this  generator  would  obtain  depends  upon  the  itotal  amount 
of  voltage  it  would  absorb  from  the  system,  and  if  the  number  of  gen- 
erators on  the  system  is  sufficient,  the  speed  might  be  excessive,  and 
would  likely  result  in  casualty  to  the  engine.  To  prevent  this,  some 
device  which  will  automatically  trip  the  field  of  the  inactive  generator, 
or  perform  an  equivalent  service,  must  be  provided.  There  are  several 
ways  of  accomplishing  this  result. 

In  the  case  of  double-ended  ferry  boats  using  the  Ward-Leonard 
system  of  control,  it  is  very  likely  that  the  energy  returned  during  quick 
stopping  or  reversal  from  full  speed  would  be  more  than  could  'be  taken 
care  of  by  the  lossesi  in  the  engines,  due  to  the  fact  that  there  are  two 
screws  returning  energy  instead  of  one.  To  prevent  the  return  of  en- 
ergy from  both  screws,  it  is  necessary  to  either  provide  a  dynamic 
braking  resistance  to  absorb  the  excess  over  what  the  engines  can  take 
care  of,  or  to  make  one  motor  inactive  during  ithis  period.  To  make  one 
motor  ineffective,  a  system  has  'been  devised  which  utilizes  a  current 
relay.  During  the  stopping  period,  this  relay  regulates  the  current  in 
one  of  the  motor  circuits  ito  a  very  small  value,  and  thus  prevents  that 
particular  motor  from  returning  energy. 


APPLICATIONS: 

Because  of  the  advantages  in  fuel  economy,  weight,  control,  re- 
liability, flexibility,  etc.,  of  the  Diesel  electric  system  of  propulsion,  it  is 
largely  applicable  to  cargo  ships,  coastwise  vessels,  liners,  certain  Naval 
craft,  fishing  boats,  yachts,  ferry  boats,  barges,  lake  'boats,  river  boats, 
cable  ships,  fire  boats;  in  fact,  any  ship  where  economy,  refinement  of 
control,  good  maneuvering  characteristics,  etc.,  are  of  any  importance. 

The  following  table  indicates  those  advantages  offered  by  Diesel 
electric  drive  which  are  of  particular  importance  in  the  various  types 
of  ships: 


384 


DIESEL  ELECTRIC  PROPULSION 

PRINCIPAL  APPLICATION   ADVANTAGES 
Main  Machinery  Only 


II 

t 


tUD 
.S  W 

3  § 
JH  o3 

OK 


Cargo  ships  _.  .XX  XX 

Coastwise  vessels  X  XX 

Liners  X  XX 

Certain  Naval  craft. _  X  X  X  X  X  X 

Fishing  boats  __X  X  X 

Yachts X  XXX 

Ferry   boats X  X  X  X  X 

Barges X  X  X  X  X  X 

Lake  boats XX  XXX 

River  boats  X  X  X  X  X  X 

Light  ships  XX  Xf 

Cable  ships  X  X  X  X  X 

Fire  boats  X  X  X  X  X 

Self-propelled  dredges  X  X  X  X  X 

*  This  refers  principally  to  stand-by  losses, 
t  Consumption  while  on  duty. 


X 


X 


A  2500  S.  H.   P.   DIESEL   ELECTRIC   DRIVE. 

G'eneral  Description  and  Arrangement:  To  convey  a  clear  idea  of 
Diesel  electric  drive,  it  is  thought  best  to  describe  a  specific  case.  The 
example  selected  is  a  2500  S.  H.  P.,  single  screw  drive,  having  four  500 
KW.,  Diesel  driven,  250  volt,  generators  supplying  power  to  a  2500  H.  P., 
double  unit,  90  R.  P.  M.  motor.  Two  75  KW  Diesel  engine  auxiliary 
generating  sets  are  provided  for  supplying  the  excitation  and  auxiliary 
load  while  at  sea.  The  following  is  the  list  of  apparatus  constituting 
the  drive: 


DIESEL  ELECTRIC   PROPULSION 


385 


1—2500  H.  P.,  90  R.  P.  M.,  double  unit,  direct  current,  500  volt,  shunt 
motor.  The  two  armatures  are  mounted  on  a  forged,  flanged  shaft  car- 
ried by  two  pedestal  bearings.  The  motor  frames  and  the  bearing 
housings  and  bearings  are  split  along  the  horizontal  center  line  to  pro- 
vide easy  access.  Fig.  1  shows  a  view  of  a  motor  of  /this  type  on  test. 
Figure  2  shows  the  field  of  a  similar  motor.  Fig.  3  shows  a  view  of  a 
small  D.  C.  propeller  motor  with  thrust  bearing  and  bedplate  arranged 
for  mounting  on  a  wooden  foundation. 


Fig.   I — Typical  Double   Unit  Direct  Current  Shunt  Propeller  Motor 


I 


Fig.  2 — Field  of  Typical  Direct  Current  Shunt  Motor  or  Generator 

4—500  KW.,  250  volt,  direct  current,  shunt  generators,  direct  coupled 
to  four  Diesel  engines.  The  generator  armature  is  mounted  on  a  forged, 
flanged  shaft  supported  at  the  commutator  end  by  a  pedestal  bearing 


386  DIESEL  ELECTRIC  PROPULSION 

and  coupled  to  the  engine  flywheel  at  the  rear  end.  As  in  the  case  of 
the  motors,  the  frame  and  bearings  are  split.  Fig.  4  shows  a  view  of  a 
Diesel  engine  generator  set,  the  arrangement  of  which  corresponds  to 
that  described. 

2 — 75  K.W.,  250  volt,  compound  wound,  direct  current,  Diesel  engine 
driven,  auxiliary  generators.  The  mechanical  arrangement  is  the  same 
as  that  of  the  main  generators.  One  of  these  sets  serves  as  a  spare. 

1 — Complement  of  motor  driven,  engine  room,  auxiliaries,  such  as 
oil  pumps,  circulating  pumps,  auxiliary  air  compressor,  sanitary,  fresh 
water,  fire  and  bilge  pumps,  etc. 


Fig.  3.    Double  Unit  Propeller  Motor  with  Bedplate  and  Self -Contained 

Thrust  Bearing 

1 — Switchboard  and  control  for  the  above  machinery. 

As  the  description  of  Diesel  engines  is  well  covered  on  other  pages 
of  this  book,  and  as  the  electrical  machines  are  briefly  described  pre- 
viously in  this  chapter,  no  further  description  is  given  here.  For  a 
comprehensive  treatise  of  the  design,  construction  and  characteristics  of 
electrical  apparatus,  the  reader  is  referred  to  any  of  the  many  reliable 
electrical  text  books  found  in  libraries  and  book  establishments.  The 
control,  its  arrangement  and  operation  are,  however,  briefly  described 
below. 

Fig.  5  shows  the  plan  view  of  the  machinery  and  its  arrangement 
in  the  engine  room.  The  four  main  Diesel  generating  sets  are  located 
forward;  and  the  motor,  auxiliary  Diesel  generating  sets,  vice  bench, 
switchboard  and  control  station  are  located  aft.  The  oil  supply  tanks 
and  other  accessories  are  located  on  the  upper  grating  (not  shown). 
The  location  of  the  control  station  is  such  that  the  operator  has  full 
view  of  the  propelling  machinery,  and  hence  the  operator  can  observe 
the  performance  at  all  times.  The  engines  are  arranged  right  and  left 
hand,  so  that  their  controls  and  gauge  boards  may  be  conveniently 
handled  and  observed.  The  entire  arrangement  provides  accessibility 
and  convenience  for  operation  and  inspection,  and  at  the  same  time  is 
not  wasteful  of  space. 


DIESEL  ELECTRIC  PROPULSION 


387 


36* 


DIESEL  ELECTRIC  PROPULSION 


DIESEL  ELECTRIC  PROPULSION 


389 


I 


*  s 
Jl 


i!| 

i  fife 


HtalUHJl 


M 


II 

i 


^  g'  <  N  K  «  «  H.  H  <  4  ^  *  « 


390  DIESEL  ELECTRIC  PROPULSION 

SWITCHBOARD   AND  CONTROL: 

Diagram:  The  control  diagram  is  shown  in  Fig.  6.  The  small  dia- 
gram in  the  lower  left  hand  corner  shows  the  scheme  of  connections, 
and  the  main  diagram  shows  the  full  details  of  connections,  including 
all  necessary  switches,  circuit  breaker,  relays,  etc.  A  glance  at  the  dia- 
gram will  show  that  all  main  machines  are  connected  in  series,  and 
furthermore,  that  the  motor  and  generator  armatures  are  interspersed 
so  that  the  current  passes  through  the  circuit  in  the  following  order: 
Generator  No.  1,  Generator  No.  2,  Motor  No.  2,  Generator  No.  3,  Gen- 
erator No.  4,  Motor  No.  1,  and  back  to  Generator  No.  1,  thus  constituting 
a  series  circuit. 

Since  the  total  voltage  of  a  chain  of  series  connected  generators  is 
the  sum  of  the  voltages  of  the  individual  machines,  the  total  effective 
voltage  in  this  case  is  4  X  250  or  1000  volts.  However,  by  interspersing 
the  motor  armatures  in  the  manner  stated,  the  ground  voltage,  or  the 
maximum  voltage  between  any  two  points  in  ithe  system  is  only  500 
volts.  Such  an  arrangement  is  advantageous  in  that  the  circuit  is  really 
a  1000-volt  system  from  a  current  standpoint,  but  only  a  500-volt  system 
from  a  voltage  or  insulation  standpoint.  In  other  words,  it  necessitates 
only  one-half  the  copper  that  would  be  required  in  a  500-volt  system 
of  this  same  capacity,  and  at  the  same  time  does  not  exceed  the  500-volt 
insulation  strain. 

Switches,  Relays,  etc.:  The  principal  switches,  relays,  etc.,  are 
designated  by  letters,  and  all  switches  performing  the  same  function  bear 
the  same  letter.  For  instance,  all  generator  cutout  switches  are  desig- 
nated by  the  letter  "A." 

"A"— Two  pole,  manually  operated,  transfer,  knife  cutout  switch 
for  generators.  When  closed  in  the  upper  position,  these  switches  con- 
nect their  respective  generators  in  the  propulsion  circuit;  and  when 
thrown  to  their  full  lower  position,  their  blades  connect  to  a  solid  bar, 
thus  cutting  the  generator  out  of  the  propulsion  circuit  and  establishing 
the  series  propulsion  circuit  through  the  bar  between  the  lower  contact 
jaws.  The  upper  and  lower  portions  of  the  blades  are  at  an  angle,  so 
that  the  switch  makes  contact  on  the  first  set  of  lower  jaws  before 
breaking  contact  on  the  upper  jaws,  and  vice  versa.  In  the  lower  throw, 
the  right  hand  lower  blade  engages  two  jaws  in  sequence.  The  first 
jaw  inserts  a  resistance  which  prevents  a  rush  of  current,  due  to  the 
residual  field  of  the  generator.  Further  closing  breaks  the  connection 
to  the  generator  armature  on  the  upper  jaws,  and  engages  the  bar  on 
the  lower  jaws.  This  switch  is  electrically  locked  against  being  thrown 
to  the  lower  position  until  (the  generator  field  has  been  opened. 

N"B" — Two  pole,  double  throw,  motor  cutout,  manually  operated 
knife  switch.  This  switch  has  no  special  features  as  it  is  not  operated 
when  the  circuit  is  alive.  The  upper  position  connects  the  motor  in  the 
propulsion  circuit,  and  the  lower  position  cuts  out  the  motor  and  es- 
tablishes the  propulsion  circuit  through  the  bar  between  the  lower  jaws. 


DIESEL  ELECTRIC  PROPULSION  391 

"C" — Three  pole,  single  throw,  main  generator  auxiliary  bus  switches. 
These  switches  are  provided  in  order  to  utilize  the  main  generators  when 
in  port  for  supplying  auxiliary  power.  It  will  be  noted  that  this  switch 
is  three  pole  to  permit  parallel  operation  (equalizer  connection),  and 
that  a  series  field  is  connected  in  the  circuit  to  give  the  generator  the 
desired  compound  characteristics. 

Switches  "A"  and  "C"  are  interlocked  so  that  only  one  or  the  other 
can  be  closed  in  the  upper  position  at  the  same  time.  This  prevents  using 
the  generator  for  two  purposes. 

"D" — Generator  field  switches. 

"E" — Motor  field  switches. 

"F" — Engine  failure  trip,  field  circuit  breaker.  These  are  provided 
to  automatically  make  the  generator  ineffective  and  to  prevent  its  motor- 
izing in  the  event  of  failure  of  its  engine.  This  breaker  is  connected  in 
the  separate  excitation  circuit  only  as  such  protection  is  unnecessary 
when  the  generators  are  operating  on  the  auxiliary  bus.  The  means  for 
opening  this  field  circuit  breaker  is  actuated  by  a  mechanical  attachment 
on  'the  engine,  or  by  a  voltage  differential  relay;  the  latter,  however,  is 
rather  complicated. 

"G" — Voltage  balance  relay  for  insuring  that  the  motor  counter  volt- 
age and  the  generator  voltage  are  approximately  at  the  same  value  be- 
fore the  automatic  main  circuit  breaker  can  be  closed.  This  lock-out 
feature  is  necessary  in  case  the  main  circuit  breaker  trips  while  the 
ship  is  under  way,  as  explained  above. 

The  device  consists  essentially  of  a  spring-closed  relay  contact  in  the 
auxiliary  circuit  of  the  closing  coil  of  the  main  automatic  circuit  breaker, 
and  a  polarized  magnet,  one  pole  of  which  is  excited  by  the  generator 
voltage  and  the  other  pole  of  which  is  excited  by  the  motor  voltage. 
When  the  two  voltages  are  equal,  the  flux  produced  in  the  magnet  core 
by  the  two  windings  is  neutralized  and  there  is  no  pull  on  the  relay  arm, 
and  the  auxiliary  circuit  to  the  main  circuit  breaker  coil  remains  intact. 
If  the  generator  voltage  is  appreciably  different  than  the  motor  voltage, 
a  pull  is  exerted  on  the  relay  arm  by  the  polarized  magnet,  and  the  relay 
contact  is  opened,  thereby  preventing  the  main  circuit  breaker  from 
closing. 

"H" — Automatic  reclosing  circuit  breaker  located  in  the  propulsion 
circuit.  As  stated  above,  the  function  of  this  device  is  to  protect  the 
machinery  against  practically  short-circuit  conditions.  The  breaker  is 
provided  with  an  inverse  time  element  overload  relay.  In  the  event  of 
very  severe  or  sustained  dangerous  overloads,  this  relay,  whose  magnet 
is  excited  by  the  main  current,  will  open  the  circuit  of  the  circuit  breaker 
closing  coil  through  the  auxiliary  relay,  and  disrupt  the  main  circuit.  To 
again  close  the  circuit  breaker,  it  is  necessary  to  adjust  the  generator 
voltage  by  means  of  the  main  control  handle,  to  the  value  of  the  motor 
counter  voltage.  To  re-establish  the  proper  generator  voltage,  it  is  merely 
necessary  to  move  the  control  handle  slowly  to  the  "increase"  or  "de- 


392  DIESEL  ELECTRIC   PROPULSION 

crease"  position,  as  the  case  may  be,  and  when  the  proper  position  is 
reached,  the  breaker  will  close  automatically. 

"I"— Auxiliary  relay  through  which  'the  operating  coil  of  the  main 
circuit  breaker  is  excited.  This  auxiliary  relay  is  provided  for  the  reason 
that  the  polarized  relay  contacts  are  of  insufficient  capacity  to  handle 
the  current  of  the  main  circuit  breaker  closing  coil. 

"J" — Field  discharge  switch  for  the  reversing  rheostat. 

"K" — Reversing  field  rheostat  for  main  generator  field  excitation 
when  generators  are  connected  to  ithe  propulsion  circuit. 

(Note. — When  the  main  generators  are  used  for  auxiliary  power,  they 
are  self-excited  and  operate  as  normal  compound  wound  generators.) 

The  simple  diagrammatic  scheme  of  the  type  of  field  rheostat  used 
for  the  control  of  the  propulsive  machinery  is  shown  in  the  lower  left 
hand  corner  of  the  main  diagram  in  Fig.  6.  The  rheostat  is  constantly 
energized  from  the  excitation  circuit.  The  leads  to  the  field  slide  sym- 
metrically over  buttons  on  the  rheostat  face  plate  which  are  connected 
to  the  resistance  at  regular  intervals.  The  arrangement  is  such  that 
the  lead  contacts  of  the  field  circuit  effectually  cross  each  other  at  the 
middle  point  of  the  rheostat  in  going  from  full  excitation  in  one  direc- 
tion to  full  excitation  in  the  other,  and  hence  not  even  a  field  circuit  is 
opened  in  going  from  ahead  to  astern. 

"L" — Overload  inverse  time  limit  relay.    This  is  described  under  "H." 

"M" — Switch  for  making  overload  relay  inoperative.  The  purpose  of 
this  is  to  provide  a  means  for  making  the  circuit  'breaker  non-automatic 
in  the  event  that  maneuvers  in  dangerous  or  restricted  waters  make  it 
imperative  to  maintain  a  positive  couple  'between  the  motors  and  gener- 
ators. To  make  the  relay  inoperative,  it  is  merely  necessary  for  the 
operator  to  press  a  button,  or  close  a  small  switch  which  bridges  the 
overload  relay  contacts. 

"N" — Three  pole,  single  throw,  knife  switches  for  connecting  the 
auxiliary  generators  to  the  main  bus.  Three  pole  switches  are  provided 
to  permit  parallel  operation. 

"O" — Overload  time  limit  circuit  'breakers  for  all  generators  when 
connected  to  the  auxiliary  bus. 

"P" — Two  pole,  transfer  switch  for  excitation  circuits.  This  switch 
is  very  similar  to  "A,"  except  that  both  throws  are  like  the  lower  throw 
of  "A"  and  have  the  preventative  resistance. 

The  purpose  of  the  switch  is  to  provide  a  ready  means  for  quickly 
transferring  the  excitation  circuits  from  one  auxiliary  generator  to  the 
other,  and  also  to  provide  an  excitation  connection  to  the  auxiliary  gen- 
erators which  is  unprotected  by  circuit  disrupting  devices. 

Figure  7  shows  a  front  view  of  a  switchboard  and  control  panel  for 
a  small  Diesel  electric  drive,  consisting  of  two  generator  units  and  one 
double  unit  motor  operating  on  the  principle  herein  described.  It  will 
be  noted  that  the  generator  field  control  handle  is  mounted  directly  on 
this  switchboard  and  is  shown  in  the  center  near  the  top.  The  switches 


DIESEL  ELECTRIC  PROPULSION 


393 


for  cutting  in  and  out  the  various  generators -and  motor  units  are  shown 
on  the  center  panel.  In  this  particular  case,  however,  the  switches  are 
not  of  the  transfer  type,  and  switching  must  be  done  on  dead  circuit. 


7_ Switchboard  and  Control  for  a  Single  Screw,  Diesel  Electric  Drive 


Fig.  8 — Front  View  of  Switchboard  for  a  Double  Ended  Ferry  Boat, 
Diesel  Electric  Drive 


394 


DIESEL  ELECTRIC  PROPULSION 


Figure  8  shows  the  front  view  of  a  switchboard  for  a  double-ended 
ferry  boat  Diesel  electric  drive.  The  control  pedestal  for  operating  the 
field  rheostat  is  located  in  the  pilot  house. 

Figure  9 — This  view  shows  the  rear  of  the  board,  the  front  view  of 
which  is  shown  in  Figure  8. 

Figure  10 — This  view  shows  a  double  face  plate  rheostat  of  the  type 
•ustHl  in  the  main  generator  circuit  for  controlling  the  propeller  motor 
aptwls.  The  rheostat  is  actuated  manually  from  any  remote  point. 


Fi<j.  9 — Rear  View  of  the  Switchboard  Shown  in  Fig  8 


Fig.  10 — Double  Face  Plate,  Main  Control  Rheostat 

Figure  11 — This  photograph  shows  a  view  of  the  generator  field  con* 
trol  pedestal  for  a  drive  having  two  motors  independently  controlled.  All 
maneuvers  of  the  ship  are  effected  by  motion  of  the  small  levers  shown 
at  the  top  of  the  pedestal. 

Figure  12  shows  a  view  of  a  control  pedestal  for  a  single  screw  ship 
such  as  is  described. 


DIESEL  ELECTRIC  PROPULSION 


395 


Fig.   II — Control  Pedestal  for 
Twin  Screw  Diesel  Electric  Drive 


Fig.  12 — Control  Pedestal  for  a 
Single  Screw  Diesel  Electric  Drive 


Operation 

Preparing  to  Get  Under  Way:  Upon  receipt  of  notice  to  prepare  for 
getting  under  way  at  full  power,  the  first  operation  is  to  see  that  all 
switches  are  in  the  proper  position.  Close  switches  "A"  and  "B"  in 
upper  position;  close  switch  "D"  to  the  right;  close  field  circuit  breakers 
"F";  close  excitation  switch  "P"  to  the  exciter  which  is  in  operation;  see 
that  generator  field  control  handle  is  in  the  "off"  position,  and  start  the 
engines. 

G-etting  Under  Way  Ahead:  Upon  signal  to  get  under  way,  close  the 
field  switches  "E"  and  "J".  (The  closing  of  "J"  establishes  power  to  the 
circuit  breaker  closing  coil.)  Move  control  handle  ahead  in  answer  to 
the  signal  and  adjust  the  speed  to  the  required  value. 

Getting  Under  Way  Astern:  Proceed  as  under  way  "ahead,"  as  de- 
scribed above,  except  move  the  control  handle  to  the  astern  direction. 

Stopping:  If  it  is  merely  desired  to  stop  the  ship  without  regard  to 
time,  move  the  control  handle  slowly  to  the  "off"  position. 

If  it  is  required  to  stop  the  ship  quickly  as  in  the  case  of  an  emer- 
gency, move  the  control  handle  toward  the  "off"  position  at  such  a  rate 
as  will  maintain  the  current  at  100  per  cent  to  150  per  cent  of  full  load 


396  DIESEL  ELECTRIC  PROPULSION 

value.  In  this  operation,  the  current  will  reverse  as  soon  as  the  gener- 
ator voltage  is  reduced  below  the  motor  counter  voltage,  and  will  stay 
reversed  until  astern  operation  ceases. 

Special  Set  Ups:  If  the  machinery  is  idle  when  changing  set  ups, 
the  switches  may  be  thrown  without  any  special  precautions.  If,  how- 
ever, the  ship  is  under  way  at  the  time  of  changing  set  ups,  reduce  the 
voltage  by  means  of  the  individual  field  rheostat  to  approximately  zero, 
and' trip  the  field  circuit  breaker  of  the  generator  which  is  to  be  taken 
out  of  service.  Then  throw  switch  "A"  to  its  extreme  lower  position 
after  the  electric  lock  described  above  has  released  the  switch  lever. 
Then  shut  down  the  engine. 

To  put  a  generator  back  into  service  while  the  ship  is  under  way, 
reverse  the  above  operations. 

Since  the  probability  of  having  to  take  a  motor  unit  out  of  service 
while  the  ship  is  under  way,  is  extremely  remote,  no  provision  is  made 
for  disconnecting  it  without  interrupting  the  circuit.  To  take  a  moitor 
unit  out  of  circuit,  move  the  main  generator  field  control  slowly  to  the 
"off"  position;  open  the  generator  field  rheostat  switch  "J"  and  the 
proper  motor  field  switch  "E";  then  throw  the  proper  switch  "B"  to  the 
lower  position.  To  re-establish  the  power,  close  the  switch  "J"  and 
operate  the  control  handle  in  the  normal  manner.  When  operating 
with  one  motor,  it  is  unnecessary  to  use  more  than  two  of  the  generators. 

Other  set  ups  must  be  performed  in  a  similar  manner. 

Securing  Electrical  Machinery  While  in  Port:  When  the  ship  has 
docked,  close  all  generator  switches  "A"  in  the  full  lower  position,  open 
motor  switches  "B,"  open  generator  field  switches  "D"  and  generator 
field  breakers  "F,"  open  generator  field  rheostat  switch  "J"  and  open 
motor  field  switches  "E." 

If  the  machines  are  to  be  idle  for  more  than  24  to  48  hours,  and  it  is 
expected  that  they  will  be  subject  to  appreciable  changes  in  temperature, 
or  to  cool  noticeable  'below  the  ambient  air  ,their  fields  should  be  ex- 
cited at  a  low  value  to  prevent  sweating  (condensation  of  miosture  on 
the  windings).  A  separate  circuit  (not  shown  in  the  diagram,)  is  usually 
provided  for  this  purpose.  Although  the  insulation  is  made  as  moisture 
resistant  as  practice  permits,  the  windings  should  not  be  allowed  to 
sweat  or  become  wet. 

Port  Operation: 

(A)  To  use  the  main  generators  in  port,  for  cargo  winches  and 
auxiliary  power  purposes,  the  following  operations  are  necessary: 

1.  Start  the  engines  which  are  to  be  used. 

2.  Close  field  switch  "D"  to  the  left  for  self-excitation. 

3.  Close  circuit  breaker  "O." 

4.  Build  up  voltage  to  normal  by  cutting  out  resistance  of  field  rheo- 
stat.    (If  the  voltage  builds  up  in  the  wrong  direction,  open  switch  "D," 
and  close  it  to  the  right,  close  switch  "J"  and  build  voltage  up  in  proper 


DIESEL  ELECTRIC  PROPULSION  397 

direction  to  about  half  value,  by  moving  the  main  control  handle.)     Open 
"J"  and  close  "D"  to  the  left,  and  repeat  as  above. 

5.  Close  switch  "C,"  thus  connecting  the  generator  on  auxiliary  bus. 
Adjust  voltage. 

(B)  To  parallel  a  second  main  generator: 
1,  2,  3,  4.  Same  as  above. 

5.  Be  sure  that  the  machine  voltage  is  the  same  as  the  bus  voltage, 
and  then  close  switch  "C." 

6.  Adjust  voltage  so  that  the  machines  divide  the  load  as  indicated 
on  the  ammeters. 

(C)  Subsequent   machines   are  paralleled   in   the   same   manner  as 
described  under  "B." 

(D)  If  one  of  the  auxiliary  sets  is  in  operation  when  the  first  main 
generator  is   connected  ito   the   auxiliary   bus,   it  must  be   paralleled   as 
in  "B." 

(E)  The  auxiliary  sets  are  paralleled  with  each  other  and  with  the 
main  generators  on  the  auxiliary  bus  as  described  in  "B." 


CONTROL    EQUIPMENT    FOR   CARGO   SHIP   WITH    FOUR   500-KW 

250-VOLT   GENERATORS   AND    ONE   2,500-H.P.    DOUBLE 

ARMATURE   PROPELLING   MOTOR 

(General  Electric  System) 

The  equipment  to  control  the  operation  of  the  electrical  propelling 
machinery  consists  of  the  apparatus  necessary  to  start,  stop,  reverse  and 
vary  the  speed  of  the  propelling  motor  and  to  cut  out  of  circuit,  any  ol 
the  generators  or  either  of  the  two  motor  armatures.  Exciter  panels  are 
provided  to  enable  the  operator  to  adjust  the  voltage  of  the  exciters  and 
connect  them  so  as  to  furnish  excitation  for  the  motor  and  generator  or 
to  furnish  auxiliary  power. 

The  following  pieces  of  apparatus  make  up  the  control  equipment 

One  Controller 

One  Generator  Field  Rheostat 

One  Main  Control  Panel 

Two  Exciter  Panels 

One  Propeller  Speed  Magneto. 

Controller:  The  controller  consists  of  a  cast  iron  frame  with  a 
sheet  metal  cover  in  which  are  mounted  the  main  control  drum  and  the 
motor  field  drum.  The  construction  of  the  frame  and  cover  is  ?uch  as  to 
make  the  controller  practically  water-tight;  the  cover  clamping  against 
felt  in  a  groove  in  the  frame.  The  control  wiring  is  taken  out  of  the 
controller  at  the  bottom  through  the  base.  There  are  two  operating  levers, 
one  for  rotating  the  main  control  drum  and  the  other  for  operating  the 


398 


DIESEL  ELECTRIC  PROPULSION 


DJ8-HOB  Equipment  of  Control  Group — Back  End  View.     Demonstrating 

Neutral  Position. 


Control  Group,  Back  View.    (General  Electric  Diesel-Electric  System) 
Showing  Interlocking  Levers  for  Hand  Control. 


DIESEL  ELECTRIC  PROPULSION  399 

motor  field  drum.  The  motor  field  lever  has  two  positions,  off  and  on, 
and  is  interlocked  with  the  main  lever  so  that  the  main  lever  cannot  be 
operated  unless  the  field  lever  is  in  the  on  position,  and  also  so  that  the 
field  lever  cannot  foe  turned  off  unless  the  main  lever  Is  in  the  off  posi- 
cuit,  sufficient  resistance  to  limit  the  generator  voltage. 

The  main  lever  when  turned  from  the  off  position,  closes  the  field 
circuit  of  the  generators  and  as  the  lever  is  turned  on  the  resistance  in 
series  with  the  generator  fields  is  cut  out  of  circuit.  To  reverse  the 
motor,  the  main  lever  is  turned  off  thru  the  off  position  to  the  astern 
points.  In  passing  through  the  off  position  the  generator  fields  are  re- 
versed and  the  generator  voltage  is  increased  as  the  resistance  is  cut 
out  of  circuit. 

Generator  Fi'eld  Rheostat:  The  generator  field  rheostat  is  composer* 
of  ribbon  wound  on  resistor  units  mounted  in  boxes  with  taps  brought 
out  which  are  connected  to  the  fingers  of  the  controller.  The  boxes  in 
which  the  units  are  mounted  are  made  up  of  perforated  sheet  metal  with 
an  insulated  base  on  which  the  terminals  are  mounted. 

Control  Parcel:  On  the  control  panel  are  mounted  instruments  neces- 
sary to  indicate  the  generated  voltage  and  current  and  the  propeller 
speed.  Also  the  switches  required  to  connect  the  generators  and  motor 
armatures  in  series  and  to  cut  out  of  circuit,  any  of  the  generators  or 
either  motor  armature.  In  addition  to  the  apparatus  just  listed,  field 
contactors  for  the  motor  fields  are  supplied  with  their  discharge  resist- 
ances, an  overload  relay  and  generator  field  contactor  with  resistance 
so  arranged  that  in  case  of  over-load  the  relay  will  trip  and  cut  into  cir- 
cuit, sufficient  resistance  to  limit  the  greater  voltage. 

Connected  to  the  panel,  there  is  mounted  a  line  contactor  so  ar- 
ranged that  during  reversal  the  line  current  is  limited  to  a  pre  deter- 
mined value  by  the  opening  of  this  contactor  which  inserts  resistance 
into  the  line. 

Exciter  Panels:  On  the  exciter  panels  are  mounted  instruments  for 
indicating  the  exciter  voltage  and  current;  the  field  rheostats  for  adjust- 
ing the  voltage  as  well  as  the  overload  circuit  breakers  with  necessary 
switches  for  connecting  exciters  either  to  the  bus  which  provides  cur- 
rent for  exciting  the  generator  and  motor  fields  or  the  bus  which  supplies 
power  for  the  auxiliaries. 

Propeller  Speed  Magn'eto:  The  propeller  speed  is  indicated  by  the 
speed  indicator  on  the  control  panel  which  is  connected  to  a  small  mag- 
neto driven  by  gears  from  the  propeller  shaft.  The  instrument  is  cali- 
brated so  as  to  read  directly  in  R.P.M.,  since  the  voltage  delivered  by 
the  magneto  varies  directly  as  the  speed. 

Operation  of  Control  Equipment:  With  the  apparatus  correctly  wired 
up  and  the  engines  running  the  voltage  on  the  exciters  is  first  adjusted 
and  the  switch  closed  so  as  to  provide  excitation  for  the  generators  and 
motor.  The  main  switches  on  the  control  panel  should  then  be  closed 
so  as  to  connect  generators  which  are  to  be  run  in  series  with  the  motor. 

When   the  signal   is   received   for  either  ahead  or  astern   the  field 


DIESEL  ELECTRIC  PROPULSION 


DIESEL  ELECTRIC  PROPULSION  401 

lever  on  the  controller  must  first  be  placed  in  the  on  position.  This 
operation  energizes  the  motor  field  contactors  which  close  and  energize 
the  moitor  fields.  With  the  field  lever  "on"  the  main  lever  can  be  moved 
either  ahead  or  astern  and  the  voltage  of  the  generators  adjusted  so  as 
to  give  the  desired  motor  speed.  For  high  speeds,  the  rated  motor  cur- 
rent should  not  be  exceeded.  The  operator  should  move  the  main  lever 
to  that  point  which  gives  full  load  current. 

In  case  of  overload,  the  generator  voltage  is  reduced  through  the 
action  of  the  overload  relay  which  causes  the  generator  field  contactor 
on  the  control  panel  to  open  and  insert  a  limiting  resistance  in  the  gen- 
erator field  circuit.  When  the  overload  is  removed  the  relay  is  returned 
to  its  operating  position  and  the  contactor  closes,  cutting  out  the  re- 
sistance. 

In  reversing,  when  the  main  lever  is  returned  to  the  first  point  the 
line  contactor  is  opened  and  a  limiting  resistance  inserted  into  the  line. 
This  resistance  is  in  circuit  when  the  main  handle  is  in  the  first  position 
ahead,  off  position,  and  first  position  astern. 


DIESEL  ENGINE— ELECTRIC   DRIVE 
The  "Mariner" — The  First  Electrically  Operated  Trawler. 

.  The  adoption  of  electric  propulsion  for  the  beam  trawler  "Mariner" 
was  the  logical  result  of  the  efficient  and  economical  operation  secured 
with  this  system  in  numerous  crafts  of  various  kinds,  both  in  America 
and  Europe  during  the  past  twelve  years. 

In  designing  the  equipment  for  the  "Mariner"  the  inherent  flexibility 
of  the  electrical  method  of  power  application  made  it  possible  to  obtain 
high  economy  in  fuel  consumption,  especially  under  cruising  conditions, 
sustained  uniform  rate  of  rotation  for  the  engines,  positive  control  of 
the  propeller  speed  at  all  times,  a  high  factor  of  safety  by  means  of 
three  separate  control  stations,  practically  instantaneous  reversal  of  the 
propeller,  and  the  use  of  electric  motors  for  driving  auxiliaries  such  as 
pumps,  compressors,  hoists  and  ventilating  blowers. 

Hull:  The  craft  is  of  wooden  construction,  and  is  rated  at  500  tons, 
with  dimensions  as  follows:  Length  over  all,  150  ft.;  beam,  24  ft.  3  in.; 
mean  draft,  11  ft.  9  in.  Her  cruising  radius  at  10  knots  is  6,000  miles, 
and  at  three-quarter  speed  9,000  miles. 

Propelling  Equipment:  The  propelling  equipment  comprises  two 
eight  cylinder,  four-cycle,  350  R.P.M.  Diesel  engines,  each  direct-connected 
to  a  165-kw.,  125-volt,  direct-current  generator.  The  two  self-excited  gen- 
erators are  normally  connected  in  series  and  supply  current  to  a  400 
H.P.,  250-volt,  200  R.P.M.  motor,  which  is  direct-coupled  to  the  propeller 
shaft, 

Two  control  stations  are  located  in  the  engine  room — one  provided 
with  remote  control,  and  one  arranged  for  emergency  manual  operation; 
a  remote-control  outfit  is  also  located  in  the  pilot  house. 


402 


DIESEL  ELECTRIC   PROPULSION 


DIESEL  ELECTRIC  PROPULSION  403 

Both  the  generators  and  the  motor  are  designed  specifically  for  sea 
duty,  and  are  provided  with  non-corrodlble  fittings  and  heat-resisting 
insulation  throughout.  The  bearings  are  a  combination  of  waste-packed 
and  oil-ring  type,  with  special  provision  against  the  leakage  of  oil  along 
the  shafts,  when  the  machines  are  out  of  their  normal  positions,  due  to 
the  rolling  and  pitching  of  the  ship.  Finally,  armatures  and  fields  are 
water-proofed,  and  the  machines  are  so  designed  as  to  prevent  flashing 
in  the  presence  of  moisture,  due  to  either  atmospherical  conditions  or 
flooding  of  the  engine  room  in  rough  seas. 

In  order  to  insure  ample  mechanical  strength  for  the  electrical  ma- 
chinery, steel  castings  were  used  for  all  rotating  parts  which  would  be 
subjected  to  unusual  strains,  or  to  shocks  incident  to  operation  during 
stormy  weather. 

The  400  H.P.  propeller  motor  is  located  forward  of  the  generating 
sets  and  has  a  normal  full-load  speed  range  of  from  160  to  200  R.P.M. 
It  is  a  compound  wound  machine  and,  when  taking  current  from  both 
generators,  it  operates  at  250  volts;  but,  for  slow  cruising,  one  engine 
can  be  shut  down  and  the  motor  then  receives  current  at  125  volts. 
Under  these  conditions  it  has  a  speed  range  of  from  70  to  160  R.F.M. 

Propeller:  The  propeller  is  94  in.  in  diameter  by  68  in.  pitch  and,  at 
full-load  rotation  of  200  R.P.M.,  gives  a  speed  of  between  7  and  10^  knots, 
depending  upon  weather  conditions.  When  hauling  the  net  the  full 
horsepower  of  the  motor  is  developed  at  a  propeller  speed  of  160  R.P.M. 

Control  Equipment:  Engine  room  control  of  all  electrical  circuits  is 
secured  by  means  of  a  main  panel  board,  on  which  are  mounted  the 
engine-room  meters,  generator  field  switches  and  resistors,  switches  and 
fuses  for  the  propelling  and  auxiliary  motors,  and  an  overload  relay 
for  the  main  hoist  motor.  The  meters  are  mounted  at  the  top  of  the 
panel  and  are  special  instruments  designed  for  shipboard  work,  being 
equipped  with  moisture-proof,  non-corrodible  parts.  The  dials  are  black 
with  white  markings,  with  radium  paint  on  the  needles  and  dial  mark- 
ings. A  duplicate  set  of  these  instruments  is  installed  in  the  pilot  house. 

The  starting  resistor  resistance  consists  of  five  boxes  of  grids,  which 
are  mounted  on  the  starboard  side  of  the  engine  room.  Just  forwards  of 
these  grids,  the  control  contactors  are  located.  This  group  consists  of 
the  necessary  curren-carrying  contactors  for  starting,  stopping  and  re- 
versing the  motor,  an  overload  relay  and  motor-shunt  field  discharge  re- 
sistance, and  is  normally  operated  by  means  of  one  of  two  master  con- 
trollers— one  located  in  the  engine  room  and  the  other  in  the  pilot  house. 

During  operation  from  either  of  these  master  controllers,  the  con- 
tactors are  closed  magnetically;  but,  if  for  any  reason  they  cannot  be 
operated  magnetically,  handles  attached  to  camshafts  are  provided  which 
may  be  operated  manually  to  close  the  contactors  in  the  desired  sequence. 
The  overload  relay,  in  case  of  overload,  opens  the  circuit  through  the 
reversing  contactor  coils,  causing  them  to  open  the  line  circuit.  The 
handles  for  manual  operation  are  so  interlocked  that  the  reversing  handle 
must  be  operated  before  the  accelerating  handle;  therefore,  the  acceler- 


404 


DIESEL  ELECTRIC  PROPULSION 


DIESEL  ELECTRIC   PROPULSION  405 

ating  handle  must  be  turned  off  before  the  reversing  handle  can  be 
moved.  This  arrangement  insures  absolute  safety  for  the  control  system 
of  the  ship,  even  in  the  very  improbable  event  of  failure  of,  or  injury 
to,  the  two  remote  control  equipments. 

One  of  the  important  advantages  of  electric  propulsion  is  that  of 
remote  control,  which  permits  the  actual  maneuvering  of  the  ship,  to  be 
accomplished  directly  in  the  pilot  house,  if  desired,  without  the  necessity 
for  signals  to  the  engine  room.  At  sea,  this  remote  control  system  is 
normally  only  a  convenience,  as  compared  with  the  ordinary  combina- 
tion pilot  house  and  engine  room  control;  but,  in  entering  and  leaving 
slips,  in  congested  harbors,  in  narrow  and  swift  current  waterways,  and 
for  quick  reversal  or  change  of  speed  in  emergencies,  its  great  practical 
value  is  obvio-us. 

This  type  of  master  controller  installed  on  the  "Mariner"  consists  of 
a  cast-iron  frame,  with  a  sheet-metal  cover,  in  which  are  mounted  a  main 
control  cylinder  and  a  reversing  cylinder.  The  construction  of  the  frame 
and  cover  is  such  as  to  make  the  controller  practically  waiter-tight  the 
cover  lamping  against  felt  in  a  groove  in  the  frame.  The  control  wiring 
is  taken  out  of  the  controller  at  the  bottom  through  the  base. 

There  are  two  handles  on  the  controller — one  main  and  one  revers- 
ing. The  main  handle  rotates  the  main  cylinder,  which  gives  17  operat- 
ing positions — one  off  position  and  one  overload  relay  reset  position. 
The  reversing  handle  rotates  the  reversing  cylinder  and  has  three  posi- 
tions; ahead,  off  and  astern. 

These  two  handles  are  so  interlocked  that  the  main  handle  cannot 
be  moved  beyond  the  overload  relay  <reset  position  unless  the  reversing 
handle  is  in  either  the  ahead  or  astern  position,  and  so  that  the  revers- 
ing handle  cannot  be  moved  unless  the  main  handle  is  in  either  the  off 
or  reset  position. 

The  rapidity  with  which  the  motor-driven  propeller  can  be  reversed 
was  demonstrated  during  the  first  trial  trip  when,  with  the  propeller 
rotating  at  from  193  to  196  revolutions  per  minute,  it  was  reversed  from 
full  speed  ahead  to  full  speed  astern  in  13  seconds;  the  actual  reversal 
of  current  in  the  motor  being  accomplished  in  two  seconds. 

Pilot-house  control  was  used  throughout  the  test  run,  operating  either 
one  or  both  generators  with  equal  facility. 

Ship's  Thrust  Bearing:  Instead  of  the  usual  rigid  multi-collar  type 
of  thrustibearing,  a  self-oiling  spring  thrust  bearing  of  the  single  collar, 
self-aligning  type  is  used,  located  aft  the  driving  motor  and  sustaining 
a  thrust  of  7,500  Ibs.,  with  the  propeller  revolving  at  200  R.P.M. 

Electric  Auxiliaries:  In  addition  to  operating  the  propelling  equip- 
ment, electrical  energy  is  used  for  lighting  and  all  auxiliary  power  pur- 
poses and,  when  the  main  engines  are  shut  down,  current  is  supplied 
by  means  of  an  independent  15-kw.,  125-volt,  oil  engine  driven  generator, 
installed  in  the  forward  end  of  the  main  engine  room  on  the  port  side. 

The  emergency  air  compressor  outfit  is  driven  by  a  direct-geared 
motor  and  is  provided  as  an  insurance  against  the  improbable  loss  of 


406 


DIESEL  ELECTRIC  PROPULSION 


DIESEL  ELECTRIC  PROPULSION  407 

starting  air  for  the  engines.  Under  these  conditions  it  will  be  utilized 
to  fill  the  air-starting  bottles,  as  the  auxiliary  generating  set  can  be 
started  by  hand. 

The  bilge  and  water-supply  pumps  are  small  centrifugal  units,  each 
driven  by  a  direct-coupled  motor,  and  near  the  main  generators  and  pro- 
peller motor  a  small  motor-driven  ventilating  set  is  utilized  to  prevent 
excessively  high  temperature  in  the  engine  room. 

The  fishing  operations  are  carried  on  toy  means  of  a  65  H,P.,  motor 
driven,  main  double-drum  hoist,  ins-tailed  on  the  main  deck  forward  of 
the  engine  room,  which  handles  the  haulage  cables  and  ropes  of  the 
net  as  they  pass  through  the  hoist  brackets  fore  and  aft  on  either  side. 
The  unloading  of  the  fish  at  the  dock  is  accomplished  by  means  of  a 
5  H.P.  motor-driven  whip  located  near  the  forward  mast. 

The  boat  has  proven  a  success  and  marks  a  new  epoch  in  motor- 
driven  ships.  She  was  built  by  Arthur  D.  Story,  of  Essex,  Mass.  The 
engines  were  built  and  installed  by  the  New  London  iShip  &  Engine  Co., 
of  Groton,  Connecticut.  All  other  equipment  was  supplied  by  the  Gen- 
eral Electric  Company  of  Schenectady,  N.  Y. 


CONTROL  EQUIPMENT  FOR  THE  ELECTRICALLY  PROPELLED 

M.  S.  "FORDONIAN" 
(General   Electric  System) 

The  main  control  equipment,  provided  to  control  the  operation  of 
two  Diesel  engine-driven  generators  and  the  propulsion  motors  consists 
of  a  control  panel  on  which  are  installed  the  various  switches,  field  rheo- 
stats, and  instruments;  a  master  controller  for  operating  the  contactors 
of  the  control  group  in  the  proper  sequence;  a  control  group  for  start- 
ing and  reversing  the  motors;  a  starting  resistor  in  connection  with  the 
control  group  used  when  starting  the  motors;  and  a  resistor  in  the  fields 
of  the  motors  used  to  obtain  speeds  of  the  motors  of  about  60  to  90 
R.P.M.  when  operating  with  only  one  generator. 

The  switches  and  wiring  are  so  arranged  that  either  one  or  both 
generators  can  be  used  to  supply  line  current  to  the  propulsion  motors. 
Constant  normal  voltage  is  held  on  the  generator,  which  is  chosen  to 
supply  excitation  current  to  the  fields  of  the  generators  and  motors, 
and  current  to  the  blower  motor,  auxiliary  panel  and  control  circuit,  while 
the  voltage  of  the  other  generator  can  be  varied  to  obtain  different  speeds 
of  the  propulsion  motor.  By  this  flexibility  of  operation,  emergency  con- 
ditions can  readily  be  taken  care  of. 

This  control  equipment  is  installed  in  the  engine  room  and  consists 
of  the  following: 

One  Control  Panel  One  Starting  Resistor 

One  Master  Controller  One  Motor  Field  Resistor 

One  Control  Group 


408 


DIESEL  ELECTRIC  PROPULSION 


Master  Controller:  The  master  controller  consists  of  a  cast  iron 
frame  in  which  are  mounted  a  main  control  cylinder  and  a  reversing 
cylinder.  A  .sheet  metal  cover  is  clamped  securely  against  felt  in  a 
groove  in  the  side  of  the  frame  so  as  to  make  the  controller  splash-proof. 
The  control  wiring  is  taken  out  through  the  base  of  the  controller. 

There  are  (2)  handles  on  the  controller,  one  main  and  one  reversing 
handle.  The  main  handle  rotates  the  main  cylinder  through  an  arc  of 
330  degrees,  thereby  covering  an  "off"  position,  an  overload  relay  "reset" 
position  and  (5)  contactor  positions  and  (12)  motor  field  resistor  posi- 


M aster-Controller,    Type   C-S    1 43  A,   Specially   Designed  /or   Marine    Use. 
Controller  Used  in  Pilot  House  and  Engine  Room. 

tions.  The  reversing  handle  rotates  the  reversing  cylinder  and  has  three 
(3)  positions:  "ahead,"  "off"  and  "astern." 

These  (2)  handles  are  so  interlocked  that  the  main  control  handle 
cannot  be  moved  beyond  the  overload  relay  reset  position  unless  the 
reversing  handle  is  in  either  the  "ahead"  oir  the  "astern"  position,  and 
so  also  that  the  reversing  lever  cannot  be  moved  unless  the  main  handle 
is  in  either  the  "off"  or  "reset"  position. 

In  ordinary  operation,  the  main  handle  will  be  thrown  only  to  the 
"reset"  position  and  not  to  the  "off"  position  except  when  the  motor  Is 


DIESEL  ELECTRIC   PROPULSION  40i) 

.o  be  stopped  for  some  time  or  the  switch  positions  are  to  be  changed. 
To  throw  from  the  "reset"  to  the  "off"  position,  a  latch  in  the  handle 
must  be  released.  This  latch  is  provided  to  prevent  going  into  the  "off" 
position,  and  thus  opening  the  motor  shunt  lield  every  time  the  motor 
is  stopped  or  reversed,  since  the  motor  shunt  field  contactors  are  always 
Closed  except  when  the  controller  handle  is  in  the  "off"  position. 

Control  Group:  The  control  group  is  designed  for  mounting  from 
above,  and  contains  four  (4)  main  contactors  for  completing  the  motor 
line,  two  being  used  for  ahead  and  two  for  astern  operations;  four  (4) 
contactors  to  reduce  and  cut  the  starting  resistance  out  of  the  circuit; 
one  (1)  overload  relay  to  trip  out  the  main  contactors  when  the  load 
is  excessive;  two  (2)  motor  field  contactors  and  the  motor  shunt  field 
discharge  resistance. 

The  main  line  and  starting  resistor  contactors  are  designed  to  carry 
the  full  load  current  of  1400  amperes  and  during  normal  operation  are 
closed  magnetically  by  means  of  solenoids  energized  from  circuits  through 
operation  of  the  master  controller.  If  for  any  reason  the  contactors  can- 
not be  operated  magnetically,  handles  are  attached  to  cam  shafts  by 
means  of  which  the  contactors  can  be  closed  manually  in  the  proper 
sequence. 

The  overload  relay  is  composed  of  one  series  coil  with  armature  and 
one  shunt  coil  with  a  plunger  carrying  two  disk  interlocks.  When  the 
relay  is  in  the  tripped  position  the  lower  disk  closes  a  circuit  through 
the  shunt  coil  of  the  relay  which  circuit  is  completed  through  the  master 
controller  in  the  reset  position.  The  completion  of  this  circuit  picks 
up  the  plunger  of  the  relay  so  that  it  is  latched  up,  thereby  closing  the 
other  disk  interlock  which  is  in  the  solenoid  circuit  of  the  four  line 
contactors.  This  solenoid  circuit  is  completed  in  the  controller  in  all 
positions  of  the  main  cylinder  except  the  "off"  and  "reset"  positions. 

In  case  of  overload  the  excessive  current  through  the  series  coil  picks 
up  the  armature  and  thereby  releases  the  plunger  carrying  the  interlocks, 
thus  causing  the  solenoid  circuit  to  be  opened  and  opening  the  two  line 
contactors  which  are  in  use. 

When  the  contactors  are  operated  manually  they  are  held  closed  by> 
cams.  Interruption  of  the  solenoid  circuit  by  tripping  of  the  overload  re- 
lay therefore  does  not  cause  the  contactors  to  open,  and  for  this  reason 
extrerrve  care  must  be  used  when  the  contactors  are  closed  by  hand  so 
that  the  load  on  the  motors  will  not  exceed  the  normal  current  value. 

The  two  (2)  field  contactors,  close  the  two  motor  shunt  field  circuits 
magnetically  on  the  "reset"  point  of  the  master  controller  and  close  the 
field  circuits  mechanically  when  operated  manually. 

The  discharge  resistance  is  connected  permanently  across  the  shunt 
fields  of  the  propelling  motors  to  limit  the  inductive  kick  when  the  field 
contactors  open. 

The  two  (2)  handles  for  manual  operation  of  the  control  group  are 
so  interlocked  that  the  reversing  handle  must  be  operated  before  the 


410  DIESEL  ELECTRIC  PROPULSION 

accelerating  handle  and  so  that  the  accelerating  handle  must  be  turned 
off  before  the  reversing  handle  can  be  moved. 

Control  Panel:  On  this  control  panel  are  mounted  the  engine  room 
instruments;  the  generator  cut-out  switches,  field  switches,  and  rheostats; 
the  combined  line  and  field  switches  for  the  main  propelling  motors;  the 
switches  for  the  blower  motor,  auxiliaries  and  the  excitation  supply  to 
the  controller.  There  are  also  mounted  the  necessary  shunts  and  gener- 
ator field  discharge  resistors. 

The  instruments  are  mounted  at  -the  top  of  the  panel  and  are  de- 
signed for  marine  use,  being  equipped  with  non-corrosive  parts.  The  dials 
are  white  with  black  markings.  Each  generator  line  is  equipped  with  a 
voltmeter  having  a  0  to  300  scale,  and  also  with  a  0  to  2500  scale  am- 
meter mounted.  A  millivoltmeter  with  a  150-0-150  R.P.M.  scale  for  pro- 
peller speed  indication  either  ahead  or  astern  and  an  ammeter  with  a  0 
to  100  scale  for  measuring  the  field  current  of  the  motors  are  mounted 
directly  beneath  the  generator  ammeters. 

The  two  generator  field  rheostats,  made  up  of  form  R,  size  U  wire 
and  ribbon  wound  resistance  units  are  supported  by  the  panel  frame 
above  the  instruments.  They  are  operated  by  the  rheostat  handles 
through  means  of  chains  and  sprockets.  The  total  resistance  of  each 
rheostat  is  approximately  50  ohms,  which  when  inserted  reduces  the 
generator  field  current  to  about  4  amperes. 

The  generator  field  rheostat  handles  and  field  switches  are  mounted 
below  the  instruments  so  that  the  operator  in  adjusting  the  generator 
fields  can  readily  watch  the  meters. 

There  are  two  single  pole,  double  throw  1600  ampere  switches  to 
connect  either  or  both  generators  across  the  propelling  motors.  Between 
these  two  switches  is  located  a  double  pole,  singel  throw  switch  and 
fuses  for  the  blower  motor. 

At  the  lower  portion  of  the  panel  and  near  the  center  line  are  mount- 
ed two  (2)  double  pole,  double  throw  switches  with  fuses,  in  each  throw. 
The  switch  to  the  right,  facing  the  panel,  is  used  to  transfer  the  field 
excitation  of  the  generators  and  motors  and  the  blower  motor  and  con- 
trol current  from  one  generator  to  the  other.  The  switch  to  the  left 
transfers  the  current  supply  to  the  auxiliary  panel  from  one  generator  to 
the  other.  These  double  pole,  double  throw  switches  should  not  be 
opened  until  the  generator  field  switches  have  been  opened,  and  in  the 
case  of  the  switch  supplying  the  auxiliary  panel  all  switching  on  this 
auxiliary  panel  'should  be  properly  made  before  transferring  the  circuit. 

On  either  side  of  the  above  switches  are  mounted  two  double  pole, 
double  throw  switches  for  cutting  out  either  of  the  motor  armatures 
and  fields  in  case  of  an  emergency.  One  side  of  the  switch  is  in  the 
motor  line  while  the  other  is  in  the  motor  field  so  that  it  is  impossible  to 
close  the  motor  line  switch  without  also  closing  the  motor  field  switch. 
These  switches  should  not  be  opened  unless  the  main  handle  of  the  con- 
troller and  the  reverse  handle  of  the  control  group  are  both  in  the  "off" 
position,  accomplished  by  moving  the  master  controller  handle  to  the 


DIESEL  ELECTRIC  PROPULSION  411 

•'oft'"  position.  Suitable  barriers  are  placed  between  the  motor  switches 
and  the  excitation  and  auxiliary  switches.  Straps  are  placed  on  the  back 
of  the  panel  near  the  generator  and  motor  cut-out  switches  and  motor  field 
switches  and  in  their  respective  circuits  to  be  disconnected  as  explained 
later  for  emergency  operation. 

No  work  must  be  done  on  the  generators  or  motors  except  when  the 
machines  are  thoroughly  isolated  by  disconnecting  all  leads  at  the  termi- 
nals of  the  machine  in  question.  The  leads  should  be  properly  taped  and 
tied  to  prevent  them  from  swinging  about. 

Starting  Resistor:  The  resistor  used  in  starting  the  motors  is  made 
up  in  four  (4)  sections  connected,  and  is  composed  of  five  (5)  boxes  of 
IG  grids. 

The  first  section  of  the  resistance  has  a  resistance  of  .36  ohms  and 
is  made  up  of  36  No.  61  IG  grids  in  series. 

The  second  section  is  cut  in  on  the  2nd  point  of  the  master  con- 
troller, in  parallel  with  the  first,  and  has  a  resistance  of  .18  ohms.  It  is 
composed  of  18  No.  61  IG  grids  connected  in  series.  The  total  resulting 
resistance  of  the  resistor  on  the  second  point  is  .12  ohms. 

The  third  section  of  resistance  is  made  up  of  24  No.  61  IG  grids,  two 
in  parallel,  and  has  a  resistance  of  .06  ohm-s.  This  section  is  cut  in  on 
the  3rd  resistance  point  of  the  controller  and  is  in  parallel  with  the  first 
two  sections,  giving  a  resulting  resistance  of  the  resistor  of  .04  ohms. 

The  fourth  section  is  composed  of  12  No.  62  IG  grids  connected  three 
in  parallel,  and  has  a  resistance  of  .02  ohms  and  is  cut  in  on  the  4th  point 
in  parallel  with  the  other  three  sections,  the  resulting  resistance  -being 
.0133  ohms. 

On  the  next  or  5th  point  of  the  controller,  all  the  resistance  is  short- 
circuited. 

Each  of  the  5  boxes  contains  18  grids,  and  is  made  up  in  a  frame.  The 
box  is  designed  for  mounting  with  the  grids  carefully  spaced  in  a  vertical 
position,  thereby  giving  the  best  ventilation. 

When  operating  with  only  one  generator  supplying  current  to  the 
motors,  it  is  possible,  though  not  advisable,  to  operate  continuously  on 
any  step  of  the  rheostat,  but  when  both  generators  are  being  used  in 
series  with  the  motors,  the  length  of  time  which  the  controller  handle 
can  be  safely  held  on  any  of  the  first  four  points  is  as  follows: 

Point  No.  1 — 20  seconds  should  not  be  exceeded. 
Point  No.  2 — 45  seconds  should  not  be  exceeded. 
Point  No.  3 — 60  seconds  should  not  be  exceeded. 
Point  No.  4 — 2  minutes  should  not  be  exceeded. 

The  above  limitations  are  derived  from  data  available  before  instal- 
lation. Actual  operating  conditions  might  permit  an  extension  of  the 
limits  given  above,  but  if  these  limits  are  exceeded,  the  grids  of  the 
starting  resistor  should  be  carefully  watched  for  overheating. 


412 


DIESEL  ELECTRIC  PROPULSION 


Tivo  Marine  Direct-Current  Generators   (for  M/8.  "Fordonian")   Rated 

MPC-8  Pole  350  KW  200  R.P.M.  Volts  Compound-Wound 

on  the  Testing  Stand. 


Marine  Direct  Current  Double  Armature  Motor   (For  M/8  "Fordonian") 

Rated  850  H.P.,  120  R.P.M. ,  500  Volts,  Consisting  of  Two  MPC-10  Pole 

425  H.P.,  120  R.P.M.,  250  Volt  Shunt  Wound  Motors  mounted  on 

one  shaft.      Port  Looking  Forward. 


DIESEL  ELECTRIC  PROPULSION  413 

Resistor  for  the  Felds  of  the  Motors:  The  resistor  for  the  two  motor 
fields  in  parallel  is  composed  of  8  units  mounted  in  a  box  frame, 
with  13  taps  brought  out,  that  is,  there  are  12  sections  of  resistance.  This 
resistance  is  required  when  the  motor  is  running  on  250  volts  to  increase 
the  speed  to  approximately  90  R.P.M. 

The  resistance  of  the  8  units  in  the  order  in  which  they  are  cut  into 
the  circuit,  is  as  follows:  0.52  ohms;  0.52  ohms;  0.52  ohms;  0.85  ohms; 
0.85  ohms;  1.7  ohms;  1.7  ohms;  1.7  ohms;  making  a  total  resistance  of 
8.36  ohms.  The  resistor  is  designed  to  vary  the  field  current  for  the  two 
fields  in  parallel  from  35  amperes  at  full  field,  to  17  amperes  at  the  90 
R.P.M.  speed  on  250  volts. 

The  terminals  of  this  resistor  are  connected  by  a  cable  to  the  master 
controller  terminals.  The  resistance  is  cut  into  the  field  circuits  as  the 
main  handle  of  the  controller  is  advanced  beyond  the  fifth  point. 

Operation  of  the  Control  Equipment:  In  preparing  to  get  under  way 
with  the  apparatus  wired  up,  either  or  both  Diesel  engines  are  brought 
up  to  speed,  depending  on  whether  the  propelling  motor  is  to  be  run  on 
250  or  500  volts.  If  both  generators  or  500  volts  are  to  be  used,  the  ex- 
citation switch  and  both  generator  field  switches  should  -be  closed  and 
the  voltage  adjusted  with  the  generator  field  rheostats  to  give  250  volts  on 
each  generator.  With  the  excitation  switch  thrown  down,  generator 
No.  1  supplies  current  for  the  fields  of  the  generators  and  motors  <and 
the  blower  and  control  circuit,  but  when  in  the  "up"  position,  generator 
No.  2  is  the  source  of  supply.  Both  generator  line  switches  and  bo'th 
motor  line  and  field  switches  should  next  be  thrown  to  the  "up"  posi- 
tion. This  places  the  generators  and  motors  in  series.  When  the  gen- 
erators are  thus  connected  to  operate  in  series,  the  series  field  switches 
located  on  the  generators  should  be  opened  if  it  is  desired  to  obtain  the 
full  propeller  speed  of  120  R.P.M. 

Start  the  blower  motor  for  ventilating  the  propulsion  motors  and 
keep  it  running  as  Ing  as  there  is  any  current  on  the  propelling  motors. 
Even  though  the  motors  might  temporarily  be  at  rest  a  condition  exists 
when  the  controller  handle  is  on  the  "reset"  position,  where  full  field  is 
j-till  maintained  on  the  motors  and  it  is  very  essential  that  ventilation  be1 
continued  under  this  condition  as  well  as  wtven  the  motors  are  running. 

The  motors  are  now  ready  for  starting  by  means  of  the  master  con- 
troller. The  reversing  lever  is  set  ahead  or  astern  as  desired  and  the 
main  handle  moved  from  the  "off"  to  the  "reset"  position.  The  operator 
should  notice  the  reading  on  the  motor  field  ammeter  to  *see  that  he  has 
full  field  of  about  35  amperes,  which  is  the  total  current  of  both  motor 
fields. 

With  this  condition  fulfilled,  the  main  handle  of  the  controller  is  then 
moved  successively  to  points  1,  2,  3,  4  and  5,  hesitating  on  each  point  for 
only  a  very  short  time,  as  explained  under  the  heading,  Starting  Resistor. 
On  point  1,  if  the  ahead  direction  has  been  chosen,  contactors  1  and  3 
in  the  control  group  are  closed.  If  the  astern  direction  were  chosen, 
contactors  2  and  4  would  close.  In  either  case  the  motors  are  connected 


414 


DIESEL  ELECTRIC  PROPULSION 


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DIESEL  ELECTRIC   PROPULSION  415 

across  the  two  generators  in  series  with  the  first  step  of  resistance. 
Points  2,  3  and  4  of  the  controller  close  contactors  8,  7  and  6  in  the  order 
named,  cutting  in  sections  2,  3  and  4  of  the  starting  resistance  in  parallel 
with  the  first  section.  The  5th  step  of  the  master  controller  closes  con- 
tactor 5,  shorting  out  the  whole  'Starting  resistor.  This  places  the  pro- 
pelling motors  across  the  two  generators  in  series  and  under  these  con- 
ditions and  with  the  ship  moving  at  full  'speed,  the  motors  will  run  at 
normal  speed  of  120  R.P.M.,  and  will  draw  approximately  full  load  cur- 
rent from  the  generators,  depending  upon  the  draft  and  other  condi- 
tions. As  explained  later,  the  exact  motor  speed  or  current  when  running 
on  both  generators,  is  adjusted  by  changing  the  voltage  of  one  of  the 
generators. 

The  full  load  current  of  the  motors  and  generators  is  approximately 
1400  amperes,  and  this  value  should  never  be  exceeded  during  continuous 
running  conditions.  Turning  the  controller  handle  beyond  the  5th  point 
weakens  the  fields  of  the  motors  and  with  both  generators  running  at 
250  volts  the  motors  will  probably  draw  considerably  over  full  load  cur- 
rent. For  this  reason,  the  operator  should  always  watch  the  generator 
ammeters  to  see  that  the  full  load  current  is  never  exceeded.  It  will 
rarely  be  necessary  to  cut  in  any  of  the  motor  field  resistance  when  both 
generators  are  supplying  current,  except  wihen  the  ship  is  light  loaded 
and  more  than  normal  speed  is  desired,  in  which  case  the  controller 
handle  is  advanced  over  the  motor  field  resistor  points  to  obtain  normal 
current  and  increased  speed. 

When  operating  under  normal  speed  conditions,  i.  e.,  each  generator 
supplying  current  at  250  volts,  the  load  on  each  generator  should  be 
equalized  as  nearly  as  possible  by  taking  excitation  current  off  one  gen- 
erator and  current  for  the  auxiliary  panel  off  the  other  generator. 

To  Operate  With  One  Generator:  If  only  one  generator  is  to  be 
used,  the  other  generator  is  cut  out  of  the  circuit  by  throwing  its'  corre- 
sponding single  pole,  double  throw  switch  diown  to  the  "cut-out"  position. 
The  doublt  pole,  double  throw  excitation  switch  is  then  thrown  down, 
if  generator  No.  1  has  been  selected,  or  up,  if  generator  No.  2  has  been 
chosen  for  excitation  purposes.  The  field  switch  of  the  generator  selected 
is  then  closed  and  the  field  rheostat  adjusted  to  give  250  volts.  The 
switches  of  the  motors  being  closed  in  the  "up"  position,  the  master 
controller  is  set  for  ahead  or  astern  and  the  main  controller  handle  moved 
successively  through  the  reset  and  first  5  points,  thus  placing  the  motors 
directly  in  series  with  the  generator.  The  motors  under  these  condi- 
tions run  with  full  field  at  approximately  60  R.P.M.  To  further  increase 
the  speed  of  the  motors  the  controller  handle  is  moved  over  the  remain- 
ing points,  thus  weakening  the  fields  of  the  motors  until  full  load  cur- 
rent of  approximately  1400  amiperes  is  drawn  by  the  motors,  whose  speed 
will  then  be  about  90  R.P.M. 

To  Reverse  the  Motors:  To  reverse  the  motors  the  main  handle  of  the 
controller  must  be  thrown  to  the  reset  position.  The  reverse  lever  may 
then  be  thrown,  after  which  the  main  handle  may  be  advanced.  This  will 
bring  the  motors  up  to  speed  in  the  reverse  direction. 


416 


DIESEL  ELECTRIC   PROPULSION 


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DIESEL  ELECTRIC   PROPULSION  417 

To  Operate  With  Both  Generators  at  Speeds  Between  90  and  120 
R.P.M.:  In  order  jto  obtain  speeds  between  90  and  120  R.P.M.  the  same 
procedure  is  followed  as  when  operating  with  both  generators  and  motors 
at  a  motor  speed  of  120  R.P.M. ,  the  only  exception  being  that  it  is  neces- 
sary to  weaken  the  field  of  the  generator  not  supplying  current  for  ex- 
citation and  auxiliary  purposes  by  cuttiug-in  the  field  rheostat  for  speeds 
from  120  'R.P.M.  down  to  105  R.P.M.  To  obtain  a  speed  range  of  90  to 
105  R.P.M.  it  is  necessary  to  close  the  series  field  switch  on  this  gener- 
ator in  addition  to  cutting  in  the  field  rheostat  as  mentioned  above. 


Emergency  Operation 

To  Operate  With  Both  Generators  With  One  Motor  Armature  Cut  Out: 
In  case  one  of  the  motors  has  been  disabled  it  can  be  cut  out  of  the  circuit 
by  throwing  its  corresponding  switch  to  the  "down"  position.  In  this  case 
only  one  generator  is  used  to  supply  line  current  to  the  motor  armature 
while  the  other  generator  is  used  to  supply  excitation  and  control  current 
to  the  motor  and  generator  fields  and  the  master  controller  and  current 
to  the  auxiliary  panel. 

If  generator  No.  1  has  been  chosen  for  excitation  purposes,  the  excita- 
tion switch  and  also  No.  1  generator  cutout  switch  must  be  thrown  to  the 
"down"  position.  At  the  -same  time  No.  2  generator  series  field  switch 
must  be  closed  and  its  cutout  switch  thrown  to  the  "up"  position  in 
order  to  supply  line  current  to  the  motor  still  operative  and  whose 
switch  should  be  closed  in  the  "up"  position. 

If  generator  No.  2  is  used  for  excitation  purposes,  its  cutout  'switch 
should  be  thrown  to  the  "down"  position,  and  the  excitation  switch  and 
No.  1  generator  cut-out  switch,  to  the  "up"  position  and  the  series  field 
switch  of  generator  No.  1  closed.  Both  generator  field  switches  should 
be  closed. 

The  field  rheostat  of  the  generator  supplying  current  to  the  arma- 
ture of  the  motor  should  be  cut  in  to  obtain  about  175  volts  before  start- 
ing and  then  cut  out  gradually  so  as  to  obtain  the  maximum  possible 
speed  of  the  ship  without  exceeding  the  maximum  allowable  current 
through  the  motor. 

250  volts  should  be  maintained  on  the  generator  supplying  excita- 
tion current,  as  this  is  the  normal  voltage  for  operating  the  control 
group  and  for  giving  full  motor  field  current. 

To  Operate  With  One  Generator  Only  and  With  One  Motor  Armature 
Cut  Out:  In  this  case,  the  procedure  will  be  the  same  as  that  given 
above,  with  the  exception  that  excitation  current  must  be  supplied  from 
an  external  source,  which  in  this  installation  is  the  auxiliary  generator. 
The  proper  connections  should  be  made  on  the  auxiliary  panel  to  connect 
with  the  line  to  the  auxiliary  switch  on  the  control  panel.  Disconnect 
the  strap  on  the  back  of  the  panel  and  in  the  line  of  the  generator  not 
being  used,  Both  the  auxiliary  and  excitation  switches  can  then  he 


418 


DIESEL  ELECTRIC  PROPULSION 


UIIOSEL  ELECTRIC  PROPULSION  419 

thrown  either  up  or  down,  depending  on  which  generator  is  to  be  used. 
If  generator  No.  1  is  to  be  used  the  auxiliary  and  excitation  switches 
should  be  thrown  up  or-  on  the  side  marked  generator  No.  2.  This  con- 
nects the  supply  from  the  auxiliary  panel  to  the  excitation  circuits  and 
also  places  the  voltmeter  of  generator  No.  2  across  this  supply.  The 
cutout  switch  of  generator  No.  1  should  be  closed  in  the  "up"  position 
and  that  of  generator  No.  2  in  the  "down"  position.  Tims  the  voltage  of 
the  supply  current  to  the  motor  armature  will  be  registered  on  generator 
No.  1  voltmeter,  while  the  voltage  of  the  auxiliary  generator  for  excita- 
tion purposes  will  be  indicated  on  the  voltmeter  of  generator  No.  2.  The 
field  switch  of  generator  No.  1  should  be  closed,  while  that  of  generator 
No.  2  should  be  left  open. 

If  generator  No.  2  be  used  ,in  place  of  generator  No.  1  the  operation 
should  be  reversed,  making  certain  that  the  strap  in  tire  line  of  generator 
No.  1  has  been  opened  and  that  of  generator  No.  2  closed. 

The  auxiliary  and  excitation  switches  should  both  be  thrown  down 
or  on  the  side  marked  generator  No.  1.  The  cut-out  switch  of  generator 
No.  2  should  be  closed  in  the  "up"  position  and  thait  of  generator  No.  1 
in  the  "down"  position.  The  field  switch  of  generator  No.  2  should  be 
closed  while  that  of  No.  1  should  be  open.  The  voltage  of  the  motor 
armature  current  will  be  registered  on  the  voltmeter  of  generator  No.  2, 
while  the  voltage  of  the  auxiliary  generator  will  be  indicated  on  the  volt- 
meter for  generator  No.  1. 

Since  the  auxiliary  generator  is  rated  at  15  kw.,  and  since  the  power 
required  for  excitation  of  one  generator  and  one  motor  field  is  about  7.5 
kw.,  and  that  required  for  the  blower  motor  about  5.5  kw.,  there  is  only 
2  kw.  remaining  for  the  auxiliary  pumps  and  lights.  It  will,  therefore, 
be  necessary  to  devise  some  method  whereby  the  necessary  auxiliaries 
may  be  kept  in  operation.  If  it  is  decided  to  shut  down  the  blower 
motor  intermittently  to  relieve  the  auxiliary  generator,  the  temperature 
of  the  motor  should  be  carefully  watched  for  overheating. 


Operating  Cautions 

In  the  course  of  operation  the  following  cautions  should  be  observed: 

1.  Never  open  the  generator  or  motor  line  switches  until  the  con- 
troller handle  has  been  placed  in  the  "off"  position  and  the  main  line 
and  motor  field  contactors  thus  opened. 

2.  Before  opening  the  generator  shunt  field  switches,  cut  in  the  re- 
sistance of  the  corresponding  field  rheostat. 

3.  Before  changing  the  .position  of  the  control  and  excitation  switch 
always  open  the  shunt  field  switches  as  explained  in  paragraph  2. 

4.  If  one  motor  alone  is  used,  only  one  generator  should  be  used  to 
supply  line  current  to  'this  motor. 

5.  Do  not  run  on  the  first  four  points  of  the  controller  to  obtain 
speed  changes  for  any  length  of  time  greater  than  that  specified  under 


420  DIESEL  ELECTRIC   PROPULSION 

the  heading,  "Starting  Resistor,"  as  this  will  overheat  the  grids  with  a 
tendency  to  burn  them  out. 

6.  When  operating  under  normal  conditions  with  both  generators 
running  in  series  with  both  motors,  the  oil  engine  driving  the  generator 
not  supplying  excitation  current  should  not  be  shut  down  until  the  con- 
troller is  moved  to  the  "off"  position,  and  its  respective  generator  switch 
thrown  down  to  the  "cu't-out"  position,  otherwise  the  unit  shut  down  will 
tend  to  run  as  a  motor  in  the  opposite  direction  from  current  supplied  hv 
the  other  generator. 

If  -the  oil  engine  which  drives  the  generator  supplying  excitation  cur- 
rent is  shut  down,  the  line  current  will  fall  off  due  to  lack  of  excitation, 
and  the  motors  will  stop. 

It  is  therefore  evident  from  the  above  conditions  that  the  controllor 
handle  should  always  be  moved  to  the  "off"  position  before  taking  a 
generating  unit  off  the  line. 

Maintenance  of  the  Control  Equipment 

The  frequency  and  thoroughness  of  inspection  necessary  to  keeo  the 
control  equipment  in  the  best  of  operation  depends  largely  on  the  oper- 
ating conditions.  While  casual  inspections  necessarily  follow  from  one's 
interest  in  the  machinery  it  is  very  essential  for  consistent  operation 
that  a  thorough  inspection  be  made  before  each  trip. 

The  inspection  of  the  various  parts  can  best  be  made  by  operating 
the  machinery  and  then  noting  any  faults. 

Operating  Test 

At  each  inspection,  the  control  group  should  be  operated  by  means 
of  the  master  controller.  To  do  this  the  single  pole  double  throw  line 
switches  of  the  generator  should  be  open  and  the  generator  field  switches 
closed  and  rheostats  adjusted  to  give  250  volts  on  each  generator  so  that 
the  master  controller  may  be  operated  first  with  one  generator  and  then 
the  other  supplying  the  control  current. 

The  controller  handle  should  be  turned  from  point  to  point  and  on 
the  reset  position  it  should  be  noticed  that  the  overload  relay  resets  and 
that  on  the  next  position  or  first  (point,  that  the  ahead  or  astern  con- 
tactors as  selected,  close  properly.  On  points  2,  3,  4  and  5  the  resist- 
ance contactors  should  close  in  the  proper  sequence  and  they  should 
operate  at  about  the  same  speed. 

Inspection 

At  each  inspection  all  parts  of  apparatus  should  be  examined, 
cleaned,  adjusted,  or  repaired  if  necessary,  and  the  following  points 
should  be  observed  as  follows: 


DIESEL  ELECTRIC  PROPULSION  421 

Master  Controller:  (a)  Inspect  for  weak  fingers,  imperfect  contact, 
and  loose  connections. 

(b)  When  dirty,  clean  the  contacts  and  apply  a  small  quantity  of 
lubricating  oil  to  the  contacts  with  a  piece  of  cheese  cloth. 

Engine  Room  Panel:      (a)  Inspect  for  loose  connections. 

(b)  Examine  the  knife  edges  of  the  switches  and  see  that  good 
contact  is  maintained. 

Control  Group:  The  cable  connections  to  the  contactors  and  over- 
load relay  should  be  examined  to  insure  that  they  are  tight. 

The  contactors  and  relay  of  the  control  group  should  be  inspected  and 
properly  maintained  by  observing  the  following: 

(a)  Examine  the  contact  tips  and  tighten  the  screws  holding  them 
if  loose. 

(b)  Renew  contact  tips  when  worn  half  way  through. 

(c)  When  renewing  a  contact  tip,  if  the  surface  against  which  it  rests 
has  become  rough  or  pitted,  due  to  poor  contact  from  a  loose  screw  or 
similar  cause,  it  should  be  made  smooth. 

(d)  The  contact  tips   close  with  a  butting  and  rolling  movement 
which  tends  to  remove  any  roughness  caused  by  arcing.     If  for  any  rea- 
son the  tips  become  extremely  rough,  they  should  be  filed  smooth. 

(e)  The  screws  holding  the  contactors  in  place  should  be  examined 
to  see  that  they  are  tight. 

(f)  The  pigtail  shunts  should  be  examined  for  wear  and  breakage. 

(g)  Examine  the  arc  chute  sides.     When  they  are  one-half  burned 
through,  they  should  be  replaced  by  new  ones. 

(h)  Inspect  for  loose  or  missing  nuts  and  screws,  broken  or  not  split 
cotter  pins,  and  broken  wipe  springs. 

Overload  Relay:      (a)  Keep  the  contact  points  clean. 

(b)  Trip  the  relay  occasionally  and  see  that  the  armature  moves 
freely. 


RECOMMENDED   PROCEDURE   FOR   DRYING  OUT  AND  TESTING 

THE   INSULATION    RESISTANCE  OF  THE  GENERATOR 

AND   MOTOR   WINDINGS 

Insulation  Resistance 

Although  the  generators  and  motors  are  provided  with  waterproof 
insulation,  this  insulation  should  be  kept  dry,  and  after  standing  for  a 
long  time,  either  during  the  period  of  installation  or  during  interruption 
of  service  after  installation,  the  insulation  and  also  other  parts  are 
Tkely  to  become  covered  with  moisture  to  a  certain  extent,  and  possibly 
the  terminals  or  other  exposed  parts  may  become  dirty,  which  will  tend 
to  reduce  the  insulation  resistance  and  make  it  unsafe  to  operate  at  the 


422  DIhJSEL  ELECTRIC  PROPULSION 

full  potential.     In  order  to  determine  the  condition  of  the  insulation,  its 
resistance  should  be  taken. 

The  insulation  resistance  can  be  readily  measured  by  the  use  of  a 
megger,  which  give;*  resistance  in  megohms.  When  this  is  not  available 
the  insulation  resistance  may  be  measured  by  means  of  a  high  resist- 
ance direct  current  voltmeter.  The  deflection  of  'the  meter  is  directly 
proportional  to  the  current  flowing  through  it  and  inversely  proportional 
to  the  resistance  of  the  circuit  with  constant  potential  across  it. 

In  this  installation  the  auxiliary  generator  can  be  used  to  supply 
a  250-volt  circuit  to  measure  the  Insulation  resistance  of  the  main  gen- 
erators and  the  motors. 

To  tesit  for  insulation  resistance,  attach  the  voltmeter  directly  across 
the  terminals  of  the  supply  line  and  note  the  reading.  Never  use  a  volt- 
meter whose  scale  registers  lower  than  the  voltage  supplied.  The  re- 
sistance to  be  measured  is  next  connected  in  series  with  the  voltmeter 
and  a  second  reading  taken  and  noted. 

The  resistance  "X"  is  then  given  by  the  formula: 

Rm  Dm  VRm 

-  whence  Rm  -=-  X  =  — 
Rm^X  V  Dm 

Where     Rm  =  the  Resistance  of  the  voltmeter  used 

Dm  =  the  deflection  of  the  voltmeter  with  the  resistance  in 

series 

V  —  the  voltage  supply  when  taking  the  reading  Dm 
X  =  the  insulation  resistance  sought. 

In  making  this  test  first  determine  whether  either  side  of  the  circuit 
is  grounded  or  has  a  low  insulation  resistance  by  connecting  the  volt- 
meter between  each  side  of  the  supply  circuit  and  ground.  Next  connect 
the  line  of  lower  insulation  resistance  to  the  frame  of  the  motor  or  gen- 
erator to  be  tested  through  a  fuse  of  5  or  10  amperes  capacity  or  a  re- 
sistor of  from  100  to  500  ohms  such  as  an  incandescent  lamp.  Failure  to 
observe  this  precaution  may  result  in  personal  injury.  One  terminal  of 
the  voltmeter  should  now  be  connected  to  the  other  line,  and  the  re- 
maining terminal  of  the  voltmeter  connected  first  to  the  frame  of  the 
machine  to  be  tested  to  determine  the  voltage  of  the  line  V  and  then 
transferred  to  the  winding  whose  insulation  is  to  be  tested.  The  resist- 
ance of  the  insulation  will  then  be  in  series  with  the  resistance  of  the 
voltmeter  and  the  reading  obtained  when  so  connected  will  be  small 
when  the  resistance  of  the  insulation  is  high. 

As  a  conservative  value  the  insulation  resistance  in  megohms  should 


DIESEL  ELECTRIC  PROPULSION  423 

To  Dry  Out  the  Windings 

When  the  insulation  resistance  is  found  ito  be  below  the  amount 
previously  specified,  the  windings  should  be  dried  out  after  determining 
that  all  exposed  terminals  and  connections  are  thoroughly  cleaned,  as 
leakage  may  be  due  to  dirty  connections  as  well  as  to  moist  insulation. 

The  following  procedure  is  recommended  to  dry  out  the  windings 
electrically: 

1.  Tie  the  boat  securely  to  the  dock. 

2.  Prepare  to  operate  with  one  generator  and  both  motors  and  with 
excitation  supplied  from  the  auxiliary  exciter.     The  operations  covering 
the  above  conditions  are  shown  'by  the  last  four  columns  of  operation 
chart   No.    2    with  the  exception   that  both   motor   cut-out   switches  are 
closed  in  the  up  position. 

3.  Select  the  generator  to  be  dried  out  first  and  turn  its  shunt  field 
rheostat  all  the  way  in  before  closing  the  shunt  field  switch. 

4.  If  generator  No.  1  is  to  be  used,  refer  to  either  the  fifth  or  sixth 
columns  of  chart  No.  2,  making1  the  proper  motor  switch  connections  as 
stated  in  paragraph  (2).     If  generator  No.  2  is  to  be  used  refer  to  either 
the  seventh  or  eighth  column  and  throw  both  motor  switches  "up"  as 
stated  above. 

5.  Note    the    generator    voltage    which    should    not   exceed    approxi- 
mately 25  per  cent  normal.     It  may  be  necessary  to  reduce  the  excitation 
voltage  of  the  auxiliary  exciter  sufficient  to  obtain  this  condition,  but  the 
voltage  should  not  be  dropped  below  a  point  sufficient  to  operate  or  keep 
the  contactors  closed. 

6.  Move  the  reverse  'handle  of  the  controller  ahead  or  astern,  de- 
pending on  the  position  of  the  boat  in  the  dock. 

7.  Follow  the  sequence  of  operation  as  shown  in  chart  No.  2  and 
note  carefully  the  line  and  field  amperes  recorded  on  each  of  the  five 
starting  resistor  points  so  as  not  to  exceed  full  load  current.     Note  also 
the  ipropeller  speed  so  as  not  to  exceed  a  value  which  might  break  away 
the  moorings. 

8.  Adjust  the  generator  field  and  exciter  field  if  necessary,  so  as  to 
obtain  the  maximum  line'  current  consistent  with  the  above  conditions. 

9.  The  temperature  of  the  windings  sihould  not  attain  85  degrees  C. 
(185  degrees  F.)   in  less  than  two  hours,  and  should  never  exceed  this 
temperature  during  the  drying  out  process. 

10.  Continue  this  drying  out  process  until  the  insulation  resistance 
is  equal  to  or  greater  than  the  amount  previously  given. 

11.  After  one  generator  is  dried  out,  repeat  the  operation  with  the 
other  generator,  following  the  same  method  as  given  above. 

12.  While  various   method's   of   drying   out  might  be   possible  with 
this  apparatus,  no  method  should  be  used  in  which  the  armature  is  not 
allowed  to  revolve,  since  local  heating  at  the  brushes  might  cause  warp- 
ing of  the  commutator. 


424 


DIESEL  ELECTRIC   PROPULSION 


DIESEL  ELECTRIC  PROPULSION 


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DIESEL  ELECTRIC  PROPULSION  427 

CAUSES  AND  REMEDY  OF  FAULTS  IN  DYNAMOS 

Fail-lire  to  Built  Up:  A  number  of  causes  may  prevent  the  field  mag- 
nets from  attaining  their  full  strength,  which  is  commonly  the  reason 
of  failure  to  built  up.  A  primary  cause  is  absence  of  residual  magnetism 
which  is  shown  by  a  ipiece  of  iron  not  'being  attracted  when  brought  near 
the  pole-pieces  when  the  dynamo  is  noit  running.  This  may  be  remedied 
by  exciting  the  field  coils  from  an  outside  source  o-,  if  the  demagnetiza- 
tion is  due  to  the  influence  of,  an  adjacent  machine  one  of  the  machines 
should  be  turned  half  way  around  or  the  magnetism  of  the  poles  re- 
versed. 

If  the  field  coil's  are  connected  so  as  to  oppose  each  other,  there  will 
be  no  resultant  magnetism  and,  therefore,  the  dynamo  cannot  generate 
its  full  E.M.F.  Nearly  all  machines  have  successive  poles  of  opposite 
polarity,  hence  a  fault  of  this  nature  can  be  detected  'by  testing  the 
polarity  by  means  of  a  corn-pass  needle.  If  the  same  end  of  the  needle  is 
attracted  by  successive  poles  it  shows  that  they  oppose  each  other.  In 
such  a  case  the  connections  of  the  field  coils  requiring  a  reversal  of 
polarity  should  be  changed. 

An  open  circuit  in  the  machine  will,  of  course,  prevent  the  flow  of 
current  and,  therefore,  the  field  magnetism  will  remain  weak.  This 
fault  may  be  located  by  a  careful  inspection  of  the  machine  or  by  test- 
ing the  parts  separately  by  the  fall  of  the  potential  method.  A  short 
circuit  in  the  machine  will  also  prevent  it  from  attaining  Its  full  E.M.F. 
Such  a  fault  may  toe  located  in  the  same  way  as  an  open  circuit. 

If  the  connections  are  such  that  the  current  generated  by  the  arma- 
ture and  flowing  through  the  field  coils  opposes  the  residual  magnetism, 
the  latter  will  be  destroyed  and  no  E.M.F.  generated.  A  reversal  of 
residual  magnetism  will  not  remedy  the  fault,  as  the  direction  of  the 
current  generated  by  the  armature  will  also  be  changed  and  destroy  the 
magnetism  as  before.  This  trouble  may  be  overcome  by  changing  the 
direction  of  the  armature,  or  by  reversing  either  the  armature  or  field 
connections.  An  incorrect  position  of  the  brushes  may  prevent  a  dynamo 
from  attaining  its  full  E.M.F.  In  the  case  of  a  shunt  dynamo,  building 
up  may  be  prevented  by  a  short  circuit  in  the  external  circuit  or  by  hav- 
ing too  great  a  load  in  starting.  In  the  case  of  a  series  dynamo,  building 
up  may  be  prevented  by  the  resistance  of  the  external  circuit  being  too 
great. 

Sparking:  This  is  a  common  trouible  and,  owing  to  the  large  number 
of  causes  to  which  it  may  be  due,  it  is  one  of  the  most  difficult  to  locate. 

An  incorrect  position  of  the  brushes  will  cause  sparking,  but  this 
is  readily  overcome  by  shifting  them  to  their  proper  position.  It  may  also 
be  due  to  the  brushes  not  being  an  equal  distance  apart  along  the  cir- 
cumference of  the  commutator  segments  between  the  forward  edges  of 
successive  sets  of  the  brushes,  which  number  should  be  the  same  in 
every  case. 


428  DIESEL  ELECTRIC  PROPULSION 

A  cause  of  sparking  which  is  evident  upon  inspection  is  a  rough  or 
uneven  commutator,  or  poor  'brush  contact.  A  small  amount  of  roughness 
in  the  commutator  may  toe  eliminated  by  use  of  a  fine  file  or  sandpaper. 
Emery  cloth  •should  never  'be  used  for  'this  purpose,  as  the  emery  par- 
ticles remain  in  the  metal  and  cut  both  commutator  and  brushes.  If  the 
commutator  is  very  rough,  uneven,  or  eccentric,  it  should  be  carefully 
turned  down  in  a  lathe  and  -smoothed  off.  Small  particles  of  copper 
which  may  have  become  lodged  in  (the  mica  insulation  during  the  process 
should  be  picked  out.  Poor  brush  contact  may  also  be  due  to  an  uneven 
brush  or  the  presence  of  dirt.  A  carbon  -brush  can  be  beveled  to  fit  the 
commutator  by  placing  it  in  its  position  and  inserting  a  strip  of  sand 
paper  between  it  and  the  commutator  and  drawing  it  back  and  forth, 
face  against  the  brush.  The  brush,  then  receives  the  same  curvature  as 
the  commutator. 

Sparking  will  result  from  an  excessive  flow  of  current,  whether  this 
excess  is  either  continuous  or  intermittent.  Overloading  of  a  machine 
or  a  line  short-circuit  may  cause  continuous  sparking.  This  cause  will 
be  evident  by  the  excessive  heating  of  the  whole  armature.  A  short  cir- 
cuit, or  a  grounded  circuit  in  the  armature  will  cause  an  excessive  cur- 
rent and,  consequently,  sparking.  These  faults  may  be  located  by  the  fall 
of  potential  method.  In  order  to  have  a  complete  short-circuit  within 
the  machine,  two  grounds  are  necessary. 

If  the  field  magnetism  is  weak  the  armature  will  cause  more  than  its 
normal  amount  of  distortion  of  field,  and  sparking  will  result.  A  condi- 
tion of  this  nature  may  be  brought  about  by  a  short-circuit,  open  circuit, 
or  grounds  in  the  field  coils,  as  well  as  by  an  incorrect  connecting  up  of 
the  coils. 

ADVANTAGE   AND    DISADVANTAGES  OF   SHUNT    MOTORS 

The  great  advantage  of  shunt  motors  is  that  their  speed  is  prac- 
tically constant. 

The  disadvantages  are  as  follows: 

1.  The  torque  increases  only  in  proportion  to  the  armature  current 
since  the  field  strength  is  constant. 

2.  There   is   a   high   potential   between   the  terminals  of   the    field 
winding. 

3.  Opening  the  field  circuit  suddenly   causes  a  large   spark  and   a 
high  potential  due  to  self  induction. 

4.  The  many  turns  of  fine  wire  of  the  field  coils  involve  extra  ex- 
pense since  fine  wire  costs  more  per  pound  than  coarse,  the  labor  of 
winding  is  considerable,  and  a  large  amount  of  insulation  is  necessary. 

5.  Where   shunt  motors  are  run  intermittently  it  is  customary  to 
keep  the  field  coils  constantly  charged,  the  motor  being  started  and  stop- 
ped by  closing  and  opening  the  armature  circuit  through  the  resistance. 
Keeping  the  fields  charged  when  the  motor  is  not  in  use  is,  of  course,  a 
loss  of  energy. 


DIESEL  ELECTRIC   PROPULSION  429 

Uses  of  Shunt  Motors:  A  constant  speed  is  of  the  greatest  import- 
ance in  some  classes  of  work,  and  this  advantage  makes  the  use  of 
shunt  motors  very  extended. 

Shunt  motors  are  used  in  machine  shops,  factories,  and  to  run  print- 
ing presses,  pumps,  elevators,  etc.,  or  in  general  where  good  speed  regu- 
lation is  required. 

CAPACITY  OF   MOTOR   FOR  PULLING 

As  a  guide  for  determining  the  maximoim  depth  of  well  at  which  a 
motor  of  a  given  rating  can  safely  be  installed  for  pulling  work,  the  fol- 
lowing formula  is  of  much  service.  It  is  based  on  the  maximum  torque 
of  the  motor,  but  has  been  found  sufficiently  conservative  so  that  the 
motor  heating  will  normally  not  be  excessive  under  the  usual  operating 
conditions. 

R  X  E  X   L  X  K 

Maximum  depth  of  well  —  - 

w  X  d 
in  which 

R  =  radio  of  motor  speed  to  corresponding  bull-wheel  speed 

E  =  mechanical  efficiency  of  rig  (usually  varying  from  0.5  to  0.7) 

L  =  number  of  load  lines  used  in  the  tackle  for  pulling  the  tubes. 

w  =  weight  of  tubing  in  Ib.  per  foot. 

d  =  diameter  of  bull-wheel  shaft  in  inches. 

K  =  a  constant,  depending  upon  the  motor  used. 

The  constant  K  is  determined  as  follows: 

1260  X  H.P.  X  T 

K  = 


in  which,  R.  P.  M. 

H.P.  =  horsepower  rating  of  motor  on  high  speed. 

T.  =  max.  torque  of  motor  in  per  cent  of  full  load  torque. 
R.P.M.  =  full  load  high  speed  of  motor. 

The  extreme  condition  whiah  may  be  encountered  is  pulling  rods 
and  tubing  together  with  the  tubing  full  of  oil.  This  may  be  taken  into 
account  by  determining  the  total  weight  per  foot  of  this  load  and  using 
this  figure  for  "w"  in  the  formula. 

ELECTRICAL    DATA: 

Volt:  The  practical  unit  of  electrical  pressure  analogous  to  head 
or  pressure  in  hydraulics. 

Ampere:  The  practical  unit  of  electrical  strength  or  rate  of  flow  of 
current.  Analogous  to  rate  of  flow  of  water  through  a  pipe  in  gallons 
per  second. 


430  DIESEL  ELECTRIC  PROPULSION 

Ohm:  The  unit  of  resistance.  Analogous  to  the  loss  of  head  due  to 
the  flow  of  water  in  a  pipe. 

Coulomb:     Unit  of  quantity  =  one  ampere  per  second. 

Volt  =  Ampere  times  Ohms. 
Ampere  =  volts  divided  by  Ohms. 
Ohm  =  Volts  divided  by  Amperes. 

WORK   AND   POWER: 

Work,  or  energy,  is  expended  in  a  circuit  or  conductor  when  a  cur- 
rent of  electricity  flows  through  it.  The  unit  of  electrical  work  or  en- 
ergy is  called  the  Joule,  after  an  eminent  English  scientist.  If  E  is  th« 
electromotive  force,  or  difference  of  potential,  in  volts  that  causes  Q 
coulombs  of  electricity  to  flow  through  a  circuit,  the  work  expended  in 
joules  is  J  =  E  X  Q. 

If  an  electromotive  force,  or  difference  of  potential,  of  E  volts  causes 
a  current  of  I  amperes  to  flow  for  t  seconds  through  a  resistance  of  R 
ohms,  then 

J  =  EU 
J  =  E*t 


R 
J  =  !2Rt 

The  joule  may  be  defined  as  the  work  done  when  I  ampere  flows 
for  I  second  through  a  resistance  of  I  ohm. 

The  watt-hour  is  an  extensively  used  unit  of  work.  Watt-hours 
equal  the  product  of  'the  average  number  of  watts  and  the  number  of 
hours  during  which  they  are  expended.  One  kilowatt-hour  —  1,000  watt- 
hours,  or  'the  product  of  the  average  number  of  kilowatts  and  the  num- 
ber of  hours. 

Power  (P)  which  is  the  rate  at  which  work  is  done,  is  equal  to  the 
work  divided  by  the  time,  and  may  be  calculated  by  one  of  the  following 
formulas: 

E2  J 

P  =  IE  =  12R  —  - 

R  t 

If  I  is  in  amperes,  R  in  ohms,  E  in  volts,  J  in  joules,  and  t  in  sec- 
onds, P  is  in  watts. 

The  watt,  or  unit  of  electric  power,  is  equal  to  1  joule  per  second. 
It  is  the  rate  at  which  work  is  expended  when  1  ampere  flows  through 
a  resistance  of  1  ohm.  The  watt  is  too  small  a  unit  for  convenient  use 
in  many  cases,  so  that  the  kilowatt  (KW.)  or  1,000  watts  is  frequently 
used.  1  H.P.  equals  746  watts;  therefore 

P  (in  watts)                               P  (in  kilowatts) 
H.P.  =  — — or,  H.P.  =  


746  .746 


DIESEL  ELECTRIC  PROPULSION 


431 


COEFFICIENTS    OF    LINEAR    EXPANSION. 


Material 


For  1°  Fahr.  For  1°  Cent. 


Aluminum .0000128  .0000230 

Brass .0000055  .0000099 

Brick,  Fire .0000049  .0000088 

Bronze .0000100  .0000180 

Copper .0000093  .0000167 

Glass _, .0000049  .0000088 

Gold .0000080  .0000144 

Iron,  Cast,  Gray .0000059  .0000106 

Iron,  Wrought .0000063  .0000113 

Lead .0000162  .0000292 

Mercury .0000333  .0000600 

Monel .0000076  .0000137 

Nickel .0000071  .0000127 

Platinum .0000049  .0000088 

Porcelain .0000020  .0000036 

Silver .0000107  .0000193 

Slate ___  .0000058  .0000104 

Steel,  Cast .0000064  .0000115 

Steel,  Rolled .0000056  .0000101 

Tin .0000124  .0000223 

Zinc .0000162  .0000292 

MELTING  POINTS. 

Material                                                                      Fahr.  Cent. 

Degrees  Degrees 

Aluminum 1217  658 

Brass 1643  895 

Bronze 1823  995 

Copper 1981  1083 

Gold 1945  1063 

Iron,  Cast,  Gray 2200-2300  1204-1260 

Iron,  Cast,  White 2000-2100  1093-1149 

Iron,  Wrought 2732  1500 

Lead 621  327 

Mercury — 37.9  — 38.8 

Monel 2408  1360 

Nickel 2646  1452 

Platinum 3191  1755 

Silver 1762  961 

.Steel,  Mild 2687  1475 

Steel,  Hard 2588  1420 

Tin 450  232 

Zinc _ 786  419 


432 


DIESEL  ELECTRIC  PROPULSION 


DIMENSIONS,    RESISTANCES   AND   SAFE    C 
OF  COPPER  WIRES: 

Diameter  in 

B.&.S. 

Mils.,  or 

Area  in 

Ohms 

Gauge 

Thousandths 

Circular 

per 

No. 

of  an  inch 

Mils. 

1,000  ft. 



1000 

1,000,000 

.01038 



894 

800,000 

.01297 



775 

600,000 

.0173 



707 

500,000 

.02076 



632 

400,000 

.02596 



548 

300,000 

.0346 

0000 

460 

211,600 

.04906 

000 

410 

167,805 

.06186 

00 

365 

133,079 

.07801 

0 

325 

105,592 

.0983 

1 

289 

83,694 

.1240 

2 

258 

66,373 

.1564 

3 

229 

52,633 

.1972 

4 

204 

41,742 

.2487 

5 

182 

33,102 

.3136 

6 

162 

26,250 

.3955 

8 

128 

16,509 

.6288 

10 

102 

10,381 

1 

12 

81 

6,530 

1.590 

14 



4,107 

2.591 

16 

51 

2,583 

4.019 

18 

40 

1,624 

6.391 

—Safe 

Amperes  — 

Rubber- 

Weather- 

covered   proof 

650 

1000 

550 

840 

450 

680 

400 

600 

325 

500 

275 

400 

225 

325 

175 

275 

150 

225 

125 

200 

100 

150 

90 

125 

80 

100 

70 

90 

55 

80 

50 

70 

35 

50 

25 

30 

20 

25 

15 

20 

6 

10 

3 

5 

H.P.,  K.W.,  AND   K.V.A. 

The  output  or  work  done  by  an  engine  is  mechanical  power  and  is 
measured  in  horsepower  (H.P.). 

The  output  of  an  alternating  current  generator  is  electric  current 
and  it  is  measured  in  kilovolt  amperes  (K.V.A.) . 

The  useful  output  of  a  power  plant  is  electric  power  and  it  is  meas- 
ured in  kilowatts  (K.W.). 

The  K.W.  output  of  standard  plants  is  reduced  somewhat  at  ex- 
tremely high  altitudes  because  the  capacity  of  the  engine  is  reduced  on 
account  of  the  rarefied  air. 

The  K.V.A.  output  of  an  alternator  or  power  plant  can  be  figured 
as  follows: 

Single  Phase: 

Volts  X  Amperes 

— =  K.V.A.   (Kilovolt-amperes) 

1000 


DIESEL  ELECTRIC  PROPULSION 

Two   Phas'e: 

(Volts  X  Amperes)    +   (Volts  X  Amperes) 

Phase  1                               Phase  2 
—  K.V.A. 


1000 


Three  Phase: 


(Volts  X  Amperes)  +  (Volts  X  Amperes)  +  (Volts  X  Amperes) 
Phase  1  Phase  2  Phase  3 

— ^-  -  —  K.V.A. 

1732 

In  an  alternating  current  circuit,  watts  or  kilowatts  (K.W.)  can  be 
measured  only  by  a  wattmeter.  They  cannot  be  found  by  multiplying 
volts  by  amperes  as  in  a  direct  current  circuit. 

Under  some  conditions,  K.  V.  A.  as  found  from  volts  and  amperes 
by  the  above  rules,  and  kilowatts  as  measured  by  a  wattmeter  on  the 
same  circuit,  may  be  the  same.  Usually,  however,  the  watts  will  be  less 
than  the  K.V.A.  If  we  find  the  watts  are  80  per  cent  of  the  K.V.A.  we 
say  the  "Power  Factor"  is  80  per  cent,  because  only  80  per  cent  of  the 
current  indicated  by  the  ampere  meters  is  transmitting  power.  The  part 
of  the  current  that  does  not  transmit  power  is  called  "Wattless  Cur- 
rent," and  but  little  ipower  is  consumed  in  producing  it,  so  when  the 
power  factor  is  low  there  may  be  a  large  output  in  volts  and  amperes 
indicated  by  the  switchboard  instruments  with  a  comparatively  small 
horsepower  load  on  the  engine. 

The  reason  for  this  is  that  the  voltage  of  an  alternating  current  is 
continually  changing.  It  runs  up  to  a  high  value  and  then  down  to  zero 
and  up  to  a  high  value  again  in  the  opposite  direction.  This  happens 
60  times  a  second  if  it  is  a  sixty-cycle  current.  On  account  of  a  mag- 
netic action  called  inductance,  there  is  usually  some  current  flowing  in 
the  circuit  at  the  instant  when  the  voltage  is  zero,  and  that  part  of  the 
current  does  not  transmit  any  power  because  for  that  moment  volts 
times  amperes  are  zero  and  there  are  no  watts. 

The  power  factor  may  be  high  at  one  time  and  low  at  another.  It 
depends  on  the  load  and  the  amount  consumed. 

E  W  E  E2          W 

Amperes  =  1      Ohms  =  R     l  =  —  R  =  — 

RE  1  W  12 

W  E2 

Volts  =  E     Watts  =  W     E  =  IR  = W  =  El  = =  Rls 

I  R 


434  DIESEL  ELECTRIC  PROPULSION 

To  Determine  the  Size  of  Copper  Wire  for  Any  Given  Service: 

Let  C.  M.  =  Cir.  Mils. 

Let  D.        =  Distance. 

Let  C.        =  Current. 

Let  L.         =  Loss  in  Volts. 

21.5  is  a  "Const-ant"  or  figure  always  used. 

C.  X  D.  X   21.5 

Then  -  -  —  Cir.  Mils. 

L. 

Example:  It  is  required  that  100  amperes  be  carried  350  feet  on  a 
110-vo'lt  circuit,  with  a  loss  of  2  per  cent  in  voltage.  What  is  the  cir. 
mils,  required? 

First,  ascertain  the  loss  in  volts,  or  2  per  cent  of  110  =  2.2  volts. 
100   X   350  X   21.5 


—  337,500  cir.  mils,  or  two  No.  000  wires. 


2.2 


Where  a  wiring  table  is  not  at  hand  and  it  is  desired  to  ascertain 
the  weight  of  any  bare  copper  conductor,  it  can  be  roughly  determined  in 
accordance  with  the  following: 

One  thousand  feet  of  wire,  having  an  area  of  1000  circular  mils, 
weighs  approximately  3  pounds,  and  the  weight  of  any  bare  conductor 
can,  therefore,  be  determined  by  multiplying  its  area  in  circular  mils 
by  .003. 


DIESEL  ELECTRIC   PROPULSION  435 

QUESTIONS  A   DIESEL    ENGINE   OPERATOR   SHOULD    BE   ABLE 

TO  ANSWER. 

GENERAL  SUBJECTS. 

(1)  Define  the  principle  of  operation  of  a  Diesel  engine. 

(2)  Define  the  TwonStroke  Cycle  operation. 

(3)  Define  the  Four-Stroke  Cycle  operation. 

(4)  Explain  the  Four  Events  in  a  cycle. 

(5)  Why  is  a  Diesel  engine  classified  as  a  "constant  pressure"  en- 
gine? 

(6)  Explain  the  meaning  of  "adiabatic  expansion." 

(7)  Explain  the  meaning  of  "isothermal  expansion." 

(8)  What  is  meant  by  "thermal  efficiency"? 

(9)  What  is  meant  by  "volumetric  efficiency"? 

(10)  What  is  meant  by  "mean  effective"  of  the  engine? 

(11)  What  is  meant  by  "mean-indicated"  pressure? 

(12)  What  is  meant  by  "mechanical  efficiency"  of  the  engine? 

(13)  What  is  meant  by  "thermo-dynamic  law"? 

(14)  What  is  cavitation  and  how  is  it  caused? 

(15)  What  is  a  hydrokineter  and  for  what  purpose  is  it  used? 

(16)  What  is  a  dynamometer  and  for  what  purpose  is  it  used? 

(17)  How  is  the  horsepower  of  a  Diesel  engine  ascertained? 

(18)  What  is  Brake  Horsepower? 

(19)  What  is  Indicated  Horsepower? 

(20)  What  superiority  has  a  Diesel  engine  over  a  steam  engine  for 
marine  propulsion? 

(21)  For  what  is  a  clinometer  used  on  shipboard? 

(22)  What  is  a  planimeteor? 

(23)  What  is  a  fair  fuel  consumption  per  horsepower  of  a  Diesel 
engine  of  600  H.P.? 

(24)  How  much  heat  temperature  F.  does  500  Ibs.  per  square  inch 
create? 

(25)  What  is  the  principle  on  which  an  ordinary  pyrometer  works? 

(26)  What  should  a  perfect  vacuum  be? 

(27)  Define  atmospheric   pressure   and   how   much   is   it  calculated 
per  cubic  foot? 

(28)  What  is  a  pneumercator,  and  what  is  its  purpose? 

(29)  What  is  the  mechanical  equivalent  of  a  heat  unit? 

Note:      The   answers    to   following   questions    may   be   obtained    by 
studying  the  subject  matter  in  the  different  chapters  of  this  book. 


436  DIESEL  ELECTRIC  PROPULSION 

(30)  What  is  meant  by  British  Thermal  Unit  and  how  do  you  de- 
termine this  measurement? 

(31)  What  is  meant  by  calorific  value  of  fuel? 

(32)  Define  the  meaning  of  specific  gravity. 

(33)  Define  the  meaning  of  viscosity. 

(34)  What  is  meant  by  coefficient? 

(35)  What  is  CO.,? 

(36)  What  is  the'ideal  percentage  of  CO.,  for  efficient  combustion? 

(37)  What  are  the  principle  constituents  of  fuel  oil? 

(38)  What  sihould  be  the  ideal  flashpoint  for  ordinary  fuel  oil? 

(39)  What  is  the  meaning  of  Beaume  or  Twaddle  degree  measure- 
ment? 

(40.)     What  is  the  usual  cause  of  spontaneous  combustion  in  bunk- 
ers? 

(41)  What    elements    should    be    considered    in    certifying    to    the 
amount  of  fuel  oil  received,  if  the  contract  is  by  barrel,  and  payments 
are  to  'be  made  >by  the  ton? 

(42)  How  many  gallons  are  there  to  a  barrel  and  how  many  barrels 
to  a  ton? 

(43)  What  precautions  should  be  taken  before  sending  a  man  into 
a  tank  which  has  contained  fuel  oil? 

(44)  How  are  pressure  gauges  tested  for  accuracy? 

(45)  What  is  meant  by  scavenging  efficiency  in  a  cycle? 

(46)  What  are  the  four  maintenance  principles  upon  which  a  Diesel 
engine  operates? 

(47)  How  is  the  fuel  injected  into  the  cylinder? 

(48)  Why  is  water-cooling  necessary? 

(49)  How  much  pressure  is  necessary  to  supply  the  cylinders  with 
fuel  oil? 

(50)  What  are  the  functions  of  injection  devices? 

(51)  Name  the  necessary  valves  on  Diesel  engines. 

(52)  What  are  the  functions  the  compressor  performs? 

(53)  What  are  reservoirs  of  cylindrical  forms  called  and  what  are 
they  intended  for? 

(54)  How  is  a  compressor  constructed? 

(55)  What  is  meant  'by  stages  on  compressors,  what  advantages  are 
secured  ? 

(56)  What  is  the  object  of  a  scavenging  pump? 

(57)  What  advantages,   if  any,   are   claimed   for  engines   operating 
by  the  opposed  piston  principle? 

(58)  What  necessitates  high  pressure  in  Diesel  cylinders? 

(59)  Can  scavenging  be  effected  without  valves? 

(60)  Explain  the  process  of  combustion  in  "heavy  oil"  engines. 


DIESEL  ELECTRIC  PROPULSION  437 

(61)  Explain   the   difference   between   the   "trunk"   type  and   cross- 
head  piston. 

(62)  What  advantages  are  claimed  for  "step"  piston? 

(63)  Explain  the  working  of  "air-operated"  piston  valves. 

(64)  What  is  the  method  of  actuating  the  valves? 

(65)  Explain  how  engines  are  timed. 

(67)  What  are  the  usual  methods  of  lubrication  on  Diesel  engines? 

(68)  How  are  pistons  on  Diesel  engines  waiter  cooled? 

(69)  How  are  injection  air  and  fuel  retarded? 

(70)  What  is  the  usual  method  of  removing  the  needle   valve  on 
fuel  valve? 

(71)  Explain   the  construction  of  the   usual  types  of  valve  attach- 
ments. 

(72)  What  materials  should  be  used  for  suction  pipes  in  bilges? 

(73)  How  many  cubic  inches  are  there  in  a  gallon  of  oil? 

(74)  What  is  the  average  percentage  of  losses  on  a  Diesel  direct 
propelled  ship,  single,  and  how  much  on  a  twin  propelled  ship? 

(75)  What   is    the    average    percentage    of    electrical   loss    between 
generator  and  motor  in  an  electrically  driven  Diesel  ship? 

(76)  Why  should  not  alternating  current  be  used  for  the  propulsion 
motors  in  an  electrically  driven  Diesel  ship? 

(77)  Explain  the  system  of  electrical  propulsion  on  Diesel  powered 
ships. 

(78)  Define  the  usual  features  to  be  found  on  fuel  oil  pumps. 

(79)  What  is  the  theoretical  lift  of  a  pump? 

(80)  What   is   a   Spray   Preheater,   for  what   purpose  are   they   in- 
stalled? 

(81)  Define  a  Spray  Air  Cooler. 

(82)  Define  the  different  methods  of  oil  filtering  systems. 

(83)  Define   an  apparatus   for   re-cooling  lubricating   oil   on   Diesel 
plants. 

(84)  What  material  is  mostly  used  to  line  stern  bearings? 

(85)  What  are  the  four  qualifications  a  good  lubricant  should  pos- 


(86)  What   are   the   necessary    constituents    tar-oil    should    possess 
when  used  for  fuel  purpose  on  Diesel  engines? 

(87)  What  are  oils  classified  as  hydro-carbons? 

(88)  What  effect  will  asphalt  percentage  to  a  large  extent  have  on 
engine? 

(89)  What  effect  will  sulphur  percentage  in  fuel  have  on  engine? 

(90)  What  effect  will  an  excessive  amount  of  water  in  fuel  have  on 
engine? 


438  DIESEL  ELECTRIC  PROPULSION 

(91)  What  importance  has  "paraffine  content"  in  fuel? 

(92)  What  effect  will  an  undue  amount  of  "ash"  have  in  fuel? 

(93)  What  is  the  "critical"  point  of  an  oil? 

(94)  What  is  the  "deadweight"  tonnage  of  a  ship? 

(95)  What  is  the  slip  of  a  propeller? 

(96)  What  is  the  pitch  of  a  propeller? 

(97)  Explain  the  object  of  the  thrust  bearing. 

(98)  Explain  the  principle  of  "semi-Diesel"  engines. 

(99)  What  are  closed  and  Wihat  are  open  nozzle  fuel  injection  de- 
vices ? 

(100)  Explain  the  principle  of  the  "Sperry  Compound  Engine". 


CHAPTER  XII. 

LOW   COMPRESSION    ENGINES. 

HEAVY  DUTY  OIL  ENGINES,  MARINE  AND  STATIONARY 
LOW  COMPRESSION 

The  low  compression  engine,  generally  termed  the  semi-Diesel  en- 
gine, has  the  distinction  that  it  operates  under  pressures  up  ito  about 
250  Ibs.  per  square  inch.  In  construction  it  is  far  simpler  and  requires 
less  knowledge  than  the  high  compression  or  usually  known  as  the  "full 
Diesel"  engine.  It  follows  in  principle  of  construction  the  two-stroke 
cycle  system.  While  there  are  manufacturers  w:ho  are  adhering  to  the 
four-stroke  cycle,  low  compression  engine,  it  must  be  agreed  that  the 
two-cycle  in  this  respect  is  universally  considered  the  ideal  construction. 

Low  Compression  Engine  Pioneer  of  All  Internal  Combustion  En- 
gines: The  statement  made  that  the  lo^w  compression  engines  are  all 
modifications  of  the  Hornsby-Akroyd  engine  must  be  disputed.  The  mod- 
ern gas  engine  as  well  as  the  Diesel  types  are  in  reality  an  outcome  of 
experiments  made  in  the  early  sixties  with  the  surface  ignition  system. 
Patents  have  been  granted  in  the  United  States  as  well  as  foreign  coun- 
tries to  inventors  creating  devices  for  power  production  through  the 
methods  of  surface  ignition.  It  was  only  after  the  electrical  age  began 
to  be  felt,  that  the  modern  gasoline  driven  engine  was  brought  to  the 
front.  Thanks  to  the  great  German  inventor,  Dr.  Rudolph  Diesel,  the 
Diesel  received  its  marked  attention. 

Theory  of  Combustion:  Oils  of  heavy  viscosity  will  not  ignite  in 
the  presence  of  air  not  sufficiently  high  in  temperature.  On  the  other 
hand,  if  the  oil  strikes  a  hot  surface  it  will  break  up  into  hydro-carbons 
of  minute  particles,  and,  when  assisted  by  an  existing  high  temperature 
in  the  cylinder,  it  will  materially  be  brought  into  useful  form.  The  in- 
itial step  in  starting  the  engine  is  in  modern  types  performed  with  the 
assistance  of  electrical  starters  receiving  current  of  electricity  from  a 
battery,  or,  in  some  cases  the  hot  bulb,  hot  pin,  etc.,  is  used.  While  the 
fuel,  coming  in  contact  on  its  entering  the  combustion  chamber,  with  the 
hot  tube  or  hot  plate,  or  as  previously  stated,  electrical  device,  the 
"kracking"  of  the  fuel  is  accomplished  before  the  piston  reaches  its 
dead  center. 

It  was  customary  in  years  gone  by  to  use  a  lighter  grade  of  oils  for 
the  use  of  semi-Diesel  engines,  but  of  late  the  engines  having  been 
brought  to  a  higher  stage  of  perfection,  and,  as  a  matter  of  fact,  any 
kind  of  fuel  oil  may  be  used  in  most  standard  types.  Some  manufactur- 


440  LOW  COMPRESSION  ENGINES 

ers  of  semi-Diesel  engines  are  entirely  ignoring  the  use  of  higher  gravi- 
ties of  oils  and  are  recommending  the  lower  grades. 

Semi-Diesel  Engine  A  Factor  of  Importance  on  Land  As  Well  As 
Marine:  When  considering  the  fact  that  the  semi-Diesel  engine  has 
been  recognized  by  the  agricultural  population,  industrial  and  marine 
service  as  a  factor  of  necessity  in  the  welfare  of  the  nation,  the  enormity 
of  numbers  in  use  will  substantiate  this  statement.  Not  alone  from  the 
standpoint  of  economy,  but  also  from  the  indisputable  fact  that  the  en- 
gine is  the  simplest  mechanism  among  power  generators,  the  adoption 
of  this  type  has  been  exceedingly  rapid.  In  earlier  years  much  trouble 
was  experienced  with  semi-Diesel  engines,  >such  as  cracking  of  cylinders, 
pre-ignition,  etc.,  which  has  been  universally  solved  by  the  experiments 
made  to  create  the  highest  type  possible.  In  particular,  pre-ignition, 
which,  in  some  instances,  was  overcome  by  the  use  of  water  injection. 
With  modern  designs  all  serious  troubles  are  entirely  eliminated 
and  the  vertical  as  well  as  the  horizontal  semi-Diesel  engine  are  highly 
satisfactory. 

VITAL   POINTS   IN   OIL   ENGINE   DESIGNS 

In  the  designing  of  oil  engines,  of  either  the  vertical  or  the  hori- 
zontal types,  many  factors  have  to  be  considered.  Where  the  engine 
follows  the  principle  of  high  compression,  a  provisioncy  must  be  made 
assuring  the  compact  design  of  the  pump  delivering  the  oil  against  exist- 
ing pressure  in  the  cylinder,  a  moderate  system  of  accomplishing  the  in- 
jection in  the  combustion  chamber,  ample  water-cooling,  and  such  means 
of  lubrication  as  tend  to  minimize  high  temperatures,  thereby  avoiding 
carbonization  of  the  lubricating  oil  and  escaping  the  attendant  complica- 
tions. 

As  will  be  seen,  when  studying  the  different  types  of  engines  illus- 
trated in  this  book,  different  methods  are  employed  in  most  every  respec- 
tive make.  To  exemplify  this,  we  will  give  a  procedure  to  be  found  on 
the  Chicago  Pneumatic  Tool  Company's  Giant  Oil  Engine. 

This  engine  differs  from  all  others  in  one  or  more  of  three  broad 
features  of  design:  The  horizontal  type  of  the  engines,  the  use  of  a 
crosshead,  and  the  use  of  a  hot  liner  in  the  combustion  chamber  as  a 
means  of  igniting  the  fuel,  instead  of  a  hot  ball,  hot  bulb  or  electric 
ignition. 

Horizontal  vs.  Vertical  Construction:  As  previously  explained,  the 
mechanism  of  a  vertical  engine  is  rather  a  disadvantage  in  so  far  as 
accessibility  is  concerned;  for  all  parts  in  the  crank  case  must  be  reached 
through  small  openings.  We  do  not  mean  to  imply  that  there  are  not 
features  in  the  vertical  engine  of  very  desirable  nature,  but  rather  to 
draw  the  attention  of  certain  matters  dealing  with  the  practical  features 
in  general  use.  If  it  becomes  necessary  to  remove  the  piston,  the  con- 
necting rod  must  toe  diconnected  from  the  crank  pin,  the  cylinder  head 
removed,  and  the  piston  drawn  out  of  the  cylinder  by  means  of  a  chain 


LOW  COMPRESSION  ENGINES 


441 


442  LOW  COMPRESSION  ENGINES 

block  or  some  form  of  hoist.  To  remove  the  crankshaft,  one  or  both 
flywheels  must  foe  taken  off,  the  flanges  which  support  the  main  bearings 
removed,  and  the  shaft  taken  out  of  the  frame  endwise;  all  of  which 
requires  considerable  extra  floor  space,  especially  in  the  case  of  engines 
direct  connected  to  electric  generators. 

In  horizontal  engines  matters  already  explained  as  causing  extra 
time  are  minimized  and  other,  rather  undesirable  features  for  stationary 
purposes  overcome.  The  horizontal  engine  is  more  desirable  for  station- 
ary power  production,  while  the  vertical  engine  is  far  preferable  for 
marine  work. 

Crossh'ead  vs.  No  Crosshead:  In  any  two-stroke  cycle  engine  not 
flitted  with  a  crosshead,  the  crankoase  must  be  as  nearly  air-tight  as 
possible.  The  air  for  scavenging  the  cylinder  must  be  compressed  in  the 
crankcase,  and  if  it  is  not  tight,  will  leak  out  and  impair  the  scavenging, 
preventing  efficient  operation  of  the  engine.  This  is  so  important  that 
some  builders  put  stuffing  'boxes  on  the  outer  ends  of  the  main  bearings. 
All  the  crank  case  covers  are  necessarily  small  and  are  'bolted  down  on 
gaskets.  This  makes  the  parts  within  the  case  very  inaccessible. 

The  design  of  Giant  Engines  enables  the  air  for  scavenging  to  be 
compressed  in  the  crank  end  of  the  cylinder,  and  an  air-tight  crankcase 
is  therefore  unnecessary. 

When  a  crosshead  Is  not  used,  the  plsiton  must  act  as  a  crosshead 
and  the  cylinder  as  a  guide.  The  piston  must  be  made  longer  than  other- 
wise necessary,  in  order  to  have  room  for  the  piston  pin  and  to  prevent 
as  much  of  the  inevitable  excessive  wear  on  both  piston  and  cylinder  as 
possible.  This  wear  is  caused  by  the  piston  being  forced  hard  against 
the  top  and  bottom  of  the  cylinder  by  the  angular  thrust  of  the  connect- 
ing rod. 

This  uneven  cylinder  wear  can  never  be  entirely  prevented  without 
the  use  of  a  crosshead.  As  the  wear  increases,  it  permits  the  oil  of  heavy 
base  to  work  back  and  under  the  piston  rings,  hardening  there,  and  caus- 
ing additional  wear.  The  advantages  do  not  stop  here.  The  extra  fric- 
tion caused  by  lengthening  the  cylinder  and  piston  is  greater  than  the 
friction  of  a  crosshead.  Engines  which  do  not  have  crossheads  soon 
become  very  hard  to  .start  on  account  of  the  loss  of  compression  due  to 
worn  piston  and  cylinder. 

Crosshead  construction  adds  great  stability  to  a  machine.  It  has 
been  definitely  established  that  the  addition  of  this  one  feature  doubles 
the  working  life  of  an  engine. 

Hot  Liner  vs.  Hot  Ball  or  Electric  Ignition:  Electric  ignition  has  not 
been  successfully  applied  to  the  firing  of  low  grade  fuels.  Engines  utilis- 
ing this  system  are  suitable  only  for  burning  kerosene  and  the  more 
volatile  fuels. 

Ignition  is  secured  in  Giant  Engines  by  injecting  the  fuel  into  a  hot 
liner.  This  hot  liner  is  not  subjected  to  bursting  pressures  nor  is  it  sub- 
ject to  breakage  from  contraction  and  expansion,  as  are  hot  balls  some- 
times used  for  ignition  purposes  in  this  type  of  engine.  Hot  balls  collect 


LOW  COMPRESSION  ENGINES 

WATER   INLET  'PURE   A'*  ™ANSFER 


443 


Position  of  Piston  at  Time  of  Combustion. 

carbons.     Especially  is  this  true  in  engines  in  which  water  injection  is 
not  used. 

In  any  engine  using  hot  ball  ignition  the  oil,  upon  its  injection  into 
the  cylinder,  comes  in  contact  with  very  little  heated  iron  as  compared 
with  the  hot  liner  method  used  in  Giant  Engines.  As  a  result  it  takes 


WATER    INLET 


Position  of  Piston  at  Time  of  Scavenging  and  Exhaust. 


444 


LOW  COMPRESSION  ENGINES 


LOW  COMPRESSION  ENGINES  445 

Much  longer  to  gasify  the  oil  which  consequently  must  be  injected  into 
the  cylinder  much  earlier  in  the  stroke  than  when  using  the  hot  liner. 
The  earlier  the  oil  is  Injected  into  the  cylinder  of  an  oil  engine,  the  more 
danger  there  is  of  pre-ignition  and  excessive  initial  pressure. 

Further,  any  engine  which  relies  for  ignition  on  a  bright  red  heat  and 
which  is  subject  to  bursting  pressure,  is  dangerous.  In  this  connection 
the  following  table  taken  from  the  "Engineering"  is  interesting  since  it 
shows  the  decrease  in  tensile  strength  of  oast  iron  and  mild  steel  at 
various  temperatures  and  was  based  on  observations  of  hot  bulb  semi- 
Diesel  Engine: 

Tensile  Tensile 


Load  Color  Temp.  -p.      «™£.°£    S'S-to!,"d 

per  Sy.  In.  per  Sq.  In. 

Light  Load  _____  Just  showing  color 

in  the  dark  _________         750  12.0  24.0 

Normal  Load  ___  Between  dull  and 

cherry  red  ___________       1100  7.5  12.0 

Over  Load  ______  Bright  cherry  _________  1400  3.5  2.5 

The  oil  upon  being  forced  into  the  combustion  chamber  in  this 
engine,  passes  through,  and  strikes  the  head  of  the  cylindrically  shaped 
liner  with  which  the  combustion  chamber  is  fitted.  The  shape  of  this 
liner  is  such  that  the  oil  is  instantly  distributed  over  its  surface,  gasified, 
and  ignited.  The  resulting  rapidity  of  ignition  permits  the  injection  of 
fuel  into  the  cylinder  late  in  the  stroke,  thereby  avoiding  the  abnormal 
pressures  incident  to  fpre-ignition. 

Giant  engines  are  running  on  any  petroleum  distillate  from  28  degrees 
Baume  scale  up  to  and  including  kerosene  that  does  not  contain  any 
more  than  1  per  cent  sulphur  or  25  per  cent  asphalt.  It  is  not  recom- 
mended that  any  of  the  lighter  distillates  burned  in  gasoline  engines  be 
used.  There  are  a  nunrber  of  oils  considerably  below  28  per  cent  Baume 
scale  on  which  Giant  engines  will  operate  satisfactorily,  but  as  this  de- 
pends upon  the  character  of  the  particular  oil,  a  general  guarantee  can- 
not te  given,  as  to  the  performance  of  satisfactory  results,  although  rec- 
ommendations to  that  effect  are  often  given  by  operators.  There  are 
also  many  crude  oils  which  can  te  used  in  these  engines,  but  it  is  danger- 
ous practice  as  they  are  likely  to  contain  sand,  grit  or  sulphur.  The 
sa'est  and  most  satisfactory  oils  are  those  furnished  by  the  oil  refineries. 
The  average  cost  in  operating  a  50  H.P.  engine  should  be  from  20  to  25 
cents  per  hour. 

Water  Injection  With  Fuel:  Increased  economy  is  secured  by  the 
use  of  water  with  the  oil.  The  water  enters  the  cylinders  through  a 
check  valve  at  a  point  just  above  the  pure  air  transfer  port,  and  is  drawn 
into  the  cylinder  with  the  pure  air.  The  water  retards  the  combustion 
of  the  oil  and  thus  keeps  the  initial  pressure  down  to  slightly  more  than 
compression  pressure.  It  also  keeps  the  cylinder  free  from  carbon,  keeps 
the  piston  rings  from  sticking,  and  aids  lubrication,  by  helping  to  keep  the 
piston  and  cylinder  walls  cool. 


446 


LOW  COMPRESSION  ENGINES 


\ 


.2 


LOW  COMPRESSION  ENGINES 


447 


Air  Starter:  On  the  Duplex  Types  of  Giant  Engines  automatic  air 
starters  are  provided.  The  compressor  equipment  for  the  system  con- 
sists of  a  small  vertical  air-cooled  single  acting  air  compressor,  driven  by 
a  gasoline  engine  of  adequate  horsepower.  An  air  receiver  of  ample 
capacity,  is  provided,  together  with  a  pressure  gauge,  pop  safety  valve, 
and  drain  cock. 

The  automatic  air  starter  consists  of  simple  plunger  valves  bolted 
to  the  su'b-'base  and  operated  by  cams  on  the  crankshaft.  These  valves 
allow  a  portion  of  the  high  pressure  air  to  act  on  small  piston  valves, 


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Muffler  Pit  for  Single  Engine. 

one  of  which  is  attached  to  each  cylinder  head.  These  in  turn  admit 
high  pressure  air  to  the  engine  cylinders.  The  entire  arrangement  is 
remarkably  simple. 

Exhaust  Piping:  Some  suggestion  is  given  here  in  regards  to  prop- 
erly fitting  of  exhaust  piping  from  the  engine.  In  illustrations  (f)  and 
(g)  a  typical  plan  of  installation  of  muffler  pit  is  seen.  When  follow- 
ing the  general  instruction  it  will  be  noticed  that  particular  attention  is 
given  to  eliminate  all  undesirable  noises  caused  by  engine  exhaust. 

Bolt  the  exhaust  flange  to  the  under  side  of  the  cylinder  and  run  the 
exhaust  pipe  from  it  to  any  point  desired,  taking  care  to  see  that  the 
pipe  does  not  come  in  contact  with  anything  inflammable.  If  it  is  very 


448 


LOW  COMPRESSION  ENGINES 


long  or  crooked,  it  should  be  increased  in  size.  It  should  be  put  together 
in  such  a  way  that  it  can  easily  be  taken  apart  for  cleaning. 

It  is  recommended  that  where  practicable,  the  water  jacket  outlet 
pipe  be  connected  to  the  exhaust.  The  introduction  of  the  cooling  water 
reduces  the  temperature,  and  deadens  the  noise  of  the  exhaust.  If  this 
connection  is  made  to  an  exhaust  line  in  which  a  muffler  is  used,  the 
drain  at  the  bottom  of  the  muffler  must  be  left  open. 

When  an  exhaust  pot  is  used,  it  should  be  placed  as  close  to  the 
engine  as  possible,  and  must  be  connected  by  the  size  of  pipe  called  for 
by  the  openings  in  the  exhaust  'pot  and  engine.  WThen  the  line  connecting 
the  exhaust  pot  and  exhaust  outlet  is  long  or  if  very  many  bends  are 
made,  it  is  recommended  to  use  a  size  larger  than  that  called  for  by 
the  exhaust  ipot  opening. 


Muffler  Pit  for  Double  Engine. 

For  installations  where  it  is  necessary  that  noise  and  smoke  be 
eliminated,  it  is  recommended  that  a  muffler  pit  of  the  type  shown  in 
Figs,  (f)  and  (g)  be  used.  Figure  (f)  shows  the  design  of  muffler  pits 
capab'e  of  taking  care  of  single  engines  up  to  80  H.P.,  while  the  design 
given  in  Fig.  (g)  will  take  care  of  Duplex  engines  ranging  from  100  H.P. 
to  160  H.P.  When  a  muffler  pit  of  the  type  illustrated  is  used,  it  is 
absolutely  necessary  that  an  overflow  of  the  size  recommended  be  used, 
and  also  that  a  sufficient  quantity  of  running  water  be  used  to  carry 
off  any  residue  or  waste  matter  that  may  come  from  the  exhaust.  With 
the  use  of  one  of  these  muffler  pits,  only  a  barely  perceptible  puff  of 
light  smoke  will  issue  from  the  discharge  pipe. 


LOW  COMPRESSION  ENGINES 


449 


INGERSOLL-RAND  OIL  ENGINES 

Oil  engines  have  been  classified  in  a  number  of  ways;  yet  those  built 
prior  to  the  present  time  can  be  divided  into  two  general  classes:  the  so- 
called  Semi-Diesel,  consuming  0.7  pounds  of  fuel  per  brake  horsepower, 
which  employs  a  hot  bulb,  hot  cap  or  other  hot  surface  to  vaporize  and  as- 
sist in  igniting  the  fuel;  and  the  full  Diesel  type,  consuming  slightly  over 
half  the  fuel,  which  employs  a  full  water-cooled  head,  but  high  cylinder 
compression,  still  more  highly  compressed  air  to  atomize  and  inject  the 
fuel  and  mechanically  operated  spray  valves  to  accurately  control  the 
fuel  injection. 


450  LOW  COMPRESSION  ENGINES 

In  the  accompanying  illustration  we  see  the  Ingersoll-Rand  Oil  En- 
gine, which  as  a  matter  of  fact  falls  in  neither  classification.  It  has  just 
as  high  an  over-all  economy  and  is  as  fully  water-cooled  as  the  Diesel 
type,  yet  it  demands  no  higher  compression  and  no  more  complicated 
fuel  injection  system  than  the  Semi-Diesel  type.  By  an  ingenious  method 
of  direct  fuel  injection,  so  perfect  is  the  fuel  atomization  that  200  1'bs. 
per  square  inch  is  quite  sufficient  to  automatically  ignite  the  fuel.  It  is 
not  a  surface-ignition  engine.  The  Ingerso'lKRand  oil  engine  is  a  dis- 
tinct type;  it  is  a  low  compression  engine,  direct  injection,  automatic 
ignition  engine. 

The  engine  uses  the  four-stroke  cycle  with  low  compression  (about 
200  Ibs.  per  square  inch),  direct  injection  of  fuel  and  has  no  other  means 
of  ignition  than  the  temperature  of  compression. 

The  advantages  of  solid  injection  are  obvious,  when  we  consider 
the  two  or  three  stage  compressor  necessary  with  the  Diesel  engine  to 
inject  the  fuel  into  the  cylinder  under  a  pressure  of  nece&sary  require- 
ment including  mechanical  equipment  necessary  on  high  compression 
engines,  whereas  in  this  low  compression  engine,  two  fifths  of  that  of 
the  Diesel  engine  the  same  results  are  accomplished,  eliminating  all 
complicated  mechanical  contrivances. 

In  glancing  over  the  efficiency  card  some  idea  as  to  the  resultant 
economy  of  this  engine  will  be  demonstrated.  It  will  be  observed  here, 
that  after  a  .pressure  of  200  pounds  to  the  square  inch  has  been  reached, 
combustion  occurs  at  constant  volume,  creating  a  pressure  of  about  400 
pounds,  from  which  the  expansion  is  almost  a  perfect  adiabatic.  Com- 
pare this  with  the  high  compression  cycle,  also  shown  in  this  chart,  where 
the  compression  is  carried  to  more  than  500  pounds  and  the  fuel  is  then 
admitted  gradually  so  as  to  produce  combustion  at  constant  pressure 
until  the  piston  has  traveled  a  portion  of  the  stroke,  when  it  also  changes 
to  adiabatic  expansion.  There  are  three  points  of  advantage  in  the  low- 
compression  cycle  which  should  be  noted: 

1.  The  mean  effective   pressure   which  is   proportional   to  the  net 
work  developed  in  the  cylinder  for  the  same  brake  horsepower  of  engine, 
need  to  be  only  85  >per  cent  of  that  of  the  high  compression  cycle.    This 
is  due  to  the  higher  mechanical  efficiency.   There  are  no  air  compressors 
to  be  driven  with  the  Ingersoll-iRand  Oil  Engine,  and  the  friction  losses 
are  in  consequence  lower. 

2.  The  mean  pressure  of  compression,  which  is  proportional  to  the 
work   done  in   the   engine    cylinder   during   the  compression    stroke,   is 
approximately  half  that  of  the  high-compression  cycle.      While  it  is  true 
that  most  of  this  work  is  not  lost,  but  being  returned  to  the  piston  during 
its  expansion  stroke,  nevertheless  the  performing  of  the  extra  work  of 
compression  by  the  piston  and  the  return  to  the  piston  of  an  equal  amount 
of  excess  work  during  the  expansion  stroke,  represents  more  wear  on 
piston,  cylinder  and  bearings. 

For  the  Same  brake  horsepower  the  low  compression  cycle  subjects 
the  engine  to  approximately  30  per  cent  less  wear.  With  parts  of  equal 


LOW  COMPRESSION  ENGINES 


451 


452  LOW  COMPRESSION  ENGINES 

dimensions   they    will   wear  considerably   longer — they   will   require   less 
attention. 

3.  The  maximum  pressure  and  temperatures  in  the  cylinder  are 
considerably  lower,  so  that  all  the  parts  that  are  designed  for  strength, 
stiffness  or  temperature  stresses  may  be  constructed  much  more  con- 
servatively. 

As  the  cycle  process  has  features  different  from  the  average  low 
compression  as  well  as  the  usual  type  of  high  compression  engine,  it 
will  be  interesting  to  follow  the  accurate  performance: 


Description  of  the  Cycle 

Suction  Stroke:  The  intake  valve  is  opened  mechanically  and  the 
piston  moves  'downward  on  the  suction  stroke,  drawing  in  a  full  charge 
of  pure  air. 

Compression  Stroke:  The  intake  valve  is  closed  by  the  valve  spring 
and  the  piston  returns,  compressing  the  air  from  the  cylinder  into  the 
combustion  chamber  to  a  pressure  of  approximately  200  pounds  per  square 
inch.  Injection  of  the  fuel  starts  near  the  end  of  the  stroke  and  is  com- 
pleted before  the  piston  has  reached  the  end  of  its  travel.  The  system 
of  fuel  injection  is  such  that  ignition  is  automatic  arid  perfect  combustion 
occurs. 

Working  Stroke:  Combustion  at  constant  volume  occurs  almost 
exactly  at  dead  center  and  the  pressure  rises  from  200  to  approximately 
400  pounds  and  the  piston  moves  downwards  on  the  working  stroke. 

Exhaust  Stroke:  Near  the  end  of  the  working  stroke,  the  exhaust 
valve  is  opened  mechanically,  the  pressure  drops,  and  the  piston  returns 
expelling  the  burned  charge. 

The  statement  is  often  made  that  since  the  fuel  cost  of  an  oil  engine 
is  so  low,  a  gain  in  economy  is  a  small  factor,  that  dependability  is  of 
prime  importance.  We  fail  to  realize,  that  dependability  is  intimately 
related  to  high  economy.  Every  heat  unit  in  the  fuel  that  is  not  trans- 
formed into  useful  work  must  be  carried  away  through  the  walls  of  the 
combustion  chamber  or  through  the  cylinder  walls  to  the  water  jacket  or 
must  be  carried  ipast  the  exhaust  valve  and  exhaust  valve  seat  during 
exhaust,  or  must  disappear  as  friction  in  bearings  or  cylinder  at  expense 
and  upkeep  and  durability  of  the  engine.  In  an  inefficient  engine,  not 
only  is  a  large  percentage  of  the  fuel  wasted,  but  in  getting  rid  of  the 
waste  heat,  serious  deterioration  of  the  engine  results.  The  waste  oil 
must  be  paid  for  in  the  fuel  bill,  paid  for  in  additional  lubrication  oil 
to  preserve  the  oil  film  on  the  overheated  piston  and  cylinder  walls,  paid 
for  in  additional  cooling  water  to  dissipate  the  waste  heat,  and  paid  for 
in  engine  upkeep.  High  fuel  economy  means  low  fuel  cost,  low  lubrica- 
tion cost,  low  cost  of  cooling  water,  low  cost  of  repairs  and  long  life  of 
engine. 


LOW  COMPRESSION  ENGINES 


453 


Valves  on  this  engine  are  of  the  mechanically  operated  poppet  type 
and  located  in  the  heads  and  surrounded  by  water  jacketing.  The  valve 
motion  is  of  the  roller  path  type,  operated  by  eccentrics'  mounted  on  the 
side  shafts.  This  makes  for  quietness  and  smooth  operation.  The  tim- 
ing of  the  valves  and  the  injection  of  the  fuel  is  obtained  from  the  side 
shaft  through  |he  medium  of  one  pair  of  spur  gears,  driven  by  the  crank- 
shaft. 


The  roller  path  motion  mentioned,  consists  of  a  floating  lever,  one 
end  of  which  rests  on  the  valve  stem  and  the  o«ther  is  attached  to  the 
eccentric  rod,  which  receives  its  motion  from  the  eccentric  on  the  side 
shaft.  The  end  of  the  floating  lever  therefore  moves  up  and  down  in 
relative  motion.  The  upper  surface  of  the  floating  lever  is  curved  and 


454 


LOW  COMPRESSION  ENGINES 


rests  against  a  stationary  block  of  slightly  smaller  radius  of  curvature. 
The  point  of  contact  between  the  two  pieces  changes  as  the  valve  opens 
and  shuts;  'having  the  effect  of  uniformly  accelerating  the  motion  of  the 
valve.  It  will  be  noted  that  at  the  moment  of  opening  of  the  valve,  con- 
siderable leverage  is  obtained  on  account  of  the  point  of  contact  being 
so  close  to  the  valve  stem.  This  means  that  a  minimum  of  stress  is 
exerted  on  the  push  rods  and  side  shaft  when  opening  the  valves  against 
the  terminal  pressure.  When  the  valve  is  opened  slightly  this  pressure 
is  destroyed,  and  the  point  of  contact  then  recedes,  so  as  to  increase  the 
speed  of  opening  of  the  Valve. 


LOW  COMPRESSION  ENGINES 


455 


The  fuel  injection  pumps,  one  for  each  cylinder,  which  spray  the 
fuel  into  the  combustion  chamber,  are  mounted  on  the  housing  adjacent 
to  the  cylinders.  They  are  operated  by  cams  from  the  side  shaft.  A 
centrifugal  two-ball  governor  driven  off  the  side  shaft  takes  control  of  the 
fuel  supply  when  the  engine  exceeds  a  pre-determined  speed.  It  is  an 
over-speed  governor.  An  oil  filter  is  provided  from  which  the  oil  flows 
by  gravity  to  the  oil  pumps.  A  pump,  driven  from  the  engine,  elevates 
the  oil  to  the  filter  from  the  main  supply. 


456 


LOW  COMPRESSION  ENGINES 


In  starting,  electric  igniters  are  employed  for  the  first  few  revolu- 
tions of  the  engine,  while  compressed  air  under  150  to  200  pounds  pres- 
sure is  admitted  to  each  cylinder  in  succession  by  the  aid  of  the  starting 
valves,  to  turn  the  engine  over.  As  the  engine  is  turned  over,  fuel  is 
injected  and  after  a  few  revolutions  the  air  is  shut  off  and  the  engine 
continues  to  ignite  entirely  by  compression.  The  engine  may  be  stopped 
for  about  10  minutes,  and  started  again  without  the  use  of  igniters. 


Part  View  of  Primm  Friction  Clutch  Coupling. 

In  the  accompanying  illustrations  the  Primm  Heavy  Duty  Oil  Engine 
is  shown.  As  will  be  observed  this  engine  is  of  very  simple  design.  It  is 
of  Semi-Diesel  classification  and  is  similar  to  the  ordinary  type  in  general 
method  of  running  operation.  The  fuel  consumption  is  no  more  than 


LOW  COMPRESSION  ENGINES  457 

six-tenths  of  a  pound  of  fuel  oil  of  a  gravity  of  24  Baume  or  better,  con- 
taining at  least  nineteen  thousand  B.T.U.'s  per  pound,  and  containing  not 
more  than  one-half  of  one  per  cent  of  moisture,  the  fluidity  of  which  allow 
it  to  flow  through  the  pipes  leading  to  fuel  pumps.  This  horsepower  test 
and  fuel  consumption  on  three-fourths  to  full  load  is  based  on  tests 
made  at  an  altitude  of  approximately  1,000  feet  above  sea  level. 

It  will  be  noted  in  the  illustration  of  the  engine,  that  the  peculiarity 
of  the  ignition  device  is  very  distinct.  Also  the  method  of  taking  the  air 
in  the  scavenging  chamber,  the  cross-head  taking  all  the  angular  thrust 
of  the  connecting  rod;  the  enclosed  crankcase  and  the  splash  lubricat- 
ing system. 

The  use  of  the  proper  amount  of  water  in  the  cylinder  of  an  oil 
engine  serves  to  maintain  a  proper  interior  temperature,  upon  which  de- 
pends perfect  combustion;  this  has  been  taken  care  of  in  this  modern 
type  of  oil  engine,  by  which  the  water  injection  into  'the  scavenging 
charge  by  automatically  measuring  the  amount  of  water  needed  with  the 
same  governor  which  controls  the  fuel  injection,  is  adhered  to. 

In  the  illustrations  pertaining  to  the  Primm  Clutch  and  Reversing 
gear,  the  ingenious  method  of  providing  the  carrying  of  heavy  loads  by 
automatic  governed  mechanical  gear  arrangement,  any  load  even  under 
the  most  difficult  conditions  are  amply  taken  care  of  and  through  this 
method  no  irregularities  on  the  engine  Itself  are  experienced. 


DE    LA   VERGNE   OIL    ENGINES 
Medium  Compression.     Pump  Injection  System.     Horizontal   Construction 

Of  the  numerous  types  of  oil  engines  manufactured  by  the  De  La 
Vergne  Machine  Co.,  the  two  best  known  engines,  Type  "DH"  and  Type 
"SI"  will  be  explained  here. 

Historical: 

The  Hornsby-Akroyd  Oil  Engine,  better  known  as  the  De  La  Vergne 
Type  "HA"  Engine,  was  introduced  by  the  De  La  Vergne  Co.  in.  1893 
for  use  in  small  power  plants  requiring  up  to  125  horsepower.  The  many 
admirable  features  of  this  type  of  prime  mover  soon  won  for  it  a  posi- 
tion of  great  popularity.  This  engine  employs  a  low  compression  ot 
about  50  pounds  per  square  inch,  and  will  operate  on  kerosene  and  light 
distillate  oils.  It  has  a  comparatively  high  fuel  consumption  but  great 
dependability.  Many  of  these  original  engines  are  still  operating  after 
twenty-five  years  of  service  and  examples  may  be  found  in  various  gov- 
ernment lighthouses  and  fortifications. 

To  meet  the  demand  for  an  engine  of  larger  size  which  would  suc- 
cessfully burn  the  heavy  grades  of  American  and  Mexican  crude  oils, 
the  Type  "FH"  Oil  Engine  was  designed  and  offered  in  1910,  in  sizes 
from  100  to  600  horsepower  -per  unit.  This  type  has  a  medium  com- 
pression of  280  pounds  per  square  inch  and  a  compressed  air  fuel  injec- 


458 


LOW  COMPRESSION  ENGINES 


tion  system.  Its  economy  is  greater  than  that  of  the  Type  "HA" 
and  it  operates  on  a  wide  range  of  oils,  from  heavy  crude  to  kerosene. 
These  engines  quickly  became  popular  for  installations  where  the  load 


demanded  the  larger  unit  and  the  improved  fuel  consumption.  One  pipe 
line  company  operates  nearly  150  De  La  Vergne  Type  "FTH"  Oil  Engines. 
In  response  to  tne  demand  for  a  small  engine  that,  like  the  Type 
"FH",  would  be  able  to  operate  with  high  economy  on  the  heavier  and 
cheaper  oils,  the  De  La  Vergne  Machine  Company  developed  and  offered 


LOW  COMPRESSION  ENGINES  469 

the  Type  "DH"  Oil  Engine,  in  sizes  from  40  to  130  horsepower  per  unit. 
These  engines  embodied  the  simple  mechanism  of  the  Type  "HA"  and 
some  of  the  important  features  of  the  Type  "FH"  Engine.  These  Type 
"DH"  Engines  during  the  next  few  years  showed  such  remarkable  re- 
sult's in  the  way  of  dependability  and  low  operating  costs,  that  a  de- 
mand naturally  followed  for  an  engine  of  this  simplified  design  adapted 
to  larger  horsepowers.  In  response  to  this  demand  the  De  La  Vergne 
Diesel  Oil  Engine  (Type  "SI")  was  brought  out. 

Cycle  of  Operation: 

The  Type  "SI"  Engine  being  a  single  acting  four-stroke  cycle  en- 
gine, four  strokes  of  the  piston  and  two  revolutions  of  the  crankshaft 
are  required  to  complete  the  cycle.  The  sequence  of  events  follows: 

Suction   Stroke: 

'The  intake  valve  is  opened  mechanically  and  piston  is  moved  for- 
ward on  suction  stroke,  drawing  in  a  charge  of  pure  air. 

Compression  Stroke: 

Intake  valve  is  closed.  Returning  piston  compresses  the  air  in  com- 
bustion chamber  to  a  pressure  of  approximately  330  Ibs.  per  sq.  inch. 
This  compression  pressure  is  ample  to  cause  ignition  because  on  account 
of  the  excellent  atomization  of  fuel  the  entire  combustion  space  is  filled 
with  a  uniformly  distributed  oil  mist. 

Working  Stroke: 

Fuel  is  injected  slightly  in  advance  of  inner  dead  center.  Combus- 
tion occurs  and  pressure  rises  from  compression  pressure  to  a  pressure 
of  about  500  Ibs.  per  sq.  inch.  Piston  starts  out  on  working  stroke. 

Exhaust  Stroke: 

The  exhaust  valve  is  mechanically  opened,  pressure  drops  and  piston 
returns  expelling  the  exhaust  gases. 

As  previously  stated,  the  Type  "SI"  engine  is  a  single-acting,  hori- 
zontal, four-stroke  cycle  engine,  operating  with  a  medium  compression 
of  about  330  pounds  per  square  inch  and  a  maximum  pressure  of  about 
500  pounds. 

The  engine  is  started  automatically  by  admission  of  air  from  air 
storage  tanks.  To  start,  crankshaft  is  placed  in  starting  position.  Ex- 
hause  valve  roller  under  relief  cam  is  shifted  to  reduce  compression 
when  starting.  Starting  air  is  then  turned  on.  A  cam  on  camshaft  suc- 
cessively opens  and  closes  starting  valve,  admitting  air  under  pressure  of 
about  150  Ibs.  at  proper  intervals.  When  engine  picks  up  speed  starting 
air  is  shut  off. 

To  stop  engine,  simply  pull  out  handle  on  fuel  pump  and  lock  it  in 
position  thus  shutting  off  oil  supply  to  cylinder  and  engine  stops  immed- 
iately. 


460 


LOW  COMPRESSION  ENGINES 


Fig.  2.     Governor  and  Fuel  Pump  Arrangement 


Figure  2  shows  fuel  pump  and  regulation.  This  is  possibly  the  most 
important  part  of  the  "SI"  engine.  The  pump  is  mounted  on  governor 
bracket  and  operated  by  a  hardened  cam  on  layshaft.  Hardened  steel 
pins  and  large  working  surfaces  are  used  on  all  fuel  pump  parts.  Pump 
plunger  and  plunger  barrel  are  accurately  fitted  together  and  provided 
with  labyrinth  packing  grooves,  eliminating  the  necessity  for  the  usual 
plunger  packing.  Suction  and  discharge  valves  with  hardened  and  re- 
movable seats  assure  absolute  tightness.  Fuel  is  preferably  stored  in  an 
underground  tank  outside  the  building  from  which  point  it  is  raised  to 
a  small  filter  standpipe  by  a  plunger  pump  mounted  on  the  engine. 


LOW  COMPRESSION  ENGINES 


461 


When  heavy  viscous  oils  are  used,  standpipe  is  provided  with  a  hot 
water  jacket.  Action  of  pump  maintains  constant  flow  of  oil  to  stand- 
pipe,  any  excess  fuel  overflowing  and  returning  to  storage  tank.  Prom 
standpipe  oil  is  withdrawn  by  engine  fuel  pump  and  delivered  to  spray 
valves. 

The    governor   is   of  the   centrifugal    type    operated    hy    spiral  gears 

from  layshaft.     The  governor  acts  on   an  overflow  valve  on   the  pump 


462 


LOW  COMPRESSION  ENGINES 


through  a  simple  linkage  so  arranged  that  the  quantity  of  fuel  permitted 
to  pass  to  the  spray  valve  is  readily  controlled,  thus  regulating  engine 
standpipe. 

Cooling  Water: 

The  Type  "®I"  Engine  requires  approximately  seven  gallons  of  cool- 
ing water  per  horsepower  hour  at  full  load.  This  water  may  be  dis- 
charged at  a  temperature  of  140°  Fahrenheit.  In  locations  where  the 
water  is  costly  or  difficult  to  obtain 'a  device  of  simple  and  inexpensive 
type  will  allow  circulating  water  to  be  used  again  and  again  with  the 
addition  of  only  five  per  cent  make-up  water.  Where  water  has  objec- 
tionable scale  forming  properties  a  closed  circulating  system  can  be 
used  which  filled  ait  the  start  with  soft  water,  uses  the  same  water 
repeatedly  with  practically  no  loss  whatever. 


Fig.  4.     Cylinder  Head  and   Valve   Gear 


As  will  be  observed  in  figure  4,  the  cylinder  head  is  provided  with 
an  air  starting  arrangement.  The  camshaft  side  of  the  head  is  provided 
with  openings  for  air  starting  valve  and  air  and  exhaust  valve  casings. 
The  latter  are  made  interchangeable  and  are  mechanically  operated 
from  the  camshaft. 


LOW  COMPRESSION  ENGINES 


463 


There  are  two  spray  valves  located  on  the  opposite  sides  of  the 
head  connecting  to  combustion  chamber  which  is  cast  on  the  inside  of 
the  cylinder  face  of  the  head.  This  arrangement  insures  complete  com- 
bustion of  fuel.  The  head  is  water  cooled  and  provided  with  large 
hand  holes  for  inspection  and  cleaning  of  water  space. 


//v  Las, 

i?  i*  it  ii 


Piston: 

The  piston  is  of  the  trunk  type  and  is  made  of  a  special  heat  re- 
sisting close  grained  gray  iron.  The  casting  is  carefully  annealed  be- 
fore machining  and  is  afterward  ground  to  exact  diameter.  The  liberal 
length  of  piston  enables  the  engine  to  reduce  the  pressure  due  to  angu- 
lar thrust  of  connecting  rod  to  about  10  Ibs.  per  sq.  inch  and  pressure 
due  to  piston  weight  is  le&s  than  one  pound  per  sq.  inch. 


464 


LOW  COMPRESSION  ENGINES 


In  this  case  the  long  trunk  piston  assures  a  large  contact  area  be- 
tween piston  and  cylinder  liner,  thus  heat  absorbed  by  the  section  of 
the  piston  head  exposed  to  combustion  chamber  is  rapidly  conducted 
through  piston  and  cylinder  liner  to  cooling  water.  The  piston  therefore 
works  under  most  favorable  lubricating  conditions,  and  water  cooling  of 
piston  head  with  attendant  complications  is  avoided.  The  highly  pol- 
ished head  end  of  the  piston  is  of  cone  shaped  design,  which  is  better 
able  to  follow  expansion  or  contraction  resulting  from  the  working  and 
exhaust  strokes,  thus  relieving  this  important  part  of  the  engine  of  all 
internal  stresses. 


LOW  COMPRESSION  ENGINES 


465 


Rated  Capacities: 

The   Type  "SI"   Engine   is   manufactured   in  the   following   standard 

sizes: 

300  H.P.  Twin  'Cylinder 
360  H.P.  Twin  Cylinder 
540  H.P.  Three  Cylinder 


100  H.P.  Single  Cylinder 
150  H.P.  Single  Cylinder 
180  H.P,  Single  Cylinder 
200  H.P.  Integral  Twin  Cylinder 


720    H.P.   Four   Cylinder 


Fig.  7.     Gross-Section  Through  Vaporizer 


/*'/</.  8. 


The  reliability  of  an  engine  is  merely  a  question 'of  its  weight  and 
speed.  As  the  weight  is  reduced,  the  reliability  is  correspondingly  low- 
ered. The  Type  "DH"  engines  weigh  over  400  Ibs.  per  horsepower,  and 
are  of  massive  construction  compared  to  two-cycle  units.  Besides  this, 


466 


LOW  COMPRESSION  ENGINES 


the  speeds  of  the  "DH"  engines  are  comparatively  slow,  which  is  con- 
ducive to  longer  life. 

Operating  at  slower  speeds  and  with  all  its  working  parts  open  to 
air,  the  "DH"  engine  is  much  cooler  than  many  other  high  speed  two- 
cycle  units  with  its  closed  crankcase.  The  "DH"  engine,  introducing  as 
it  does  a  large  volume  of  oxygen  for  combustion,  injecting  the  fuel  only 
at  the  end  of  compression  stroke,  employing  a  separate  stroke  for  ex- 
pelling the  burnt  charge,  making  use  of  exhaust  induction  to  complete 
the  scavenging  and  employing  a  separate  stroke  for  drawing  in  the 


Fig.  9.    Fuel  Economy  Curve  of  "DH''  Type  of  De  La  Vergne 


fresh  charge  of  air,  can  ibe  appreciated  as  a  machine  of  high  develop- 
ment among  power  producers  of  modern  types. 

The  "DH"  engines  are  equipped  for  automatic  air  starting.  A  suit- 
able air  receiver  is  provided.  To  start,  the  vaporizer  is  heated  and  the 
fuel  pump  is  operated  to  inject  the  charge  of  oil  into  the  vaporizer. 

The  air  valve  connecting  to  the  tank  is  opened.  This  engages  the 
automatic  starting  valve  which  is  then  successfully  opened  and  closed 
by  a  cam  on  the  layshaft.  Compressed  air  from  the  starting  tank  is 
admitted  to  the  cylinder  and  forces  the  piston  outward.  When  the  en- 
gine gathers  speed  the  air  is  shut  off  and  the  engine  then  operates 
under  its  own  power. 

To  completely  burn  heavy  and  tar  constituent  fuels  and  employ  mod- 
erate compression  the  fuel  must  be  thoroughly  atomized  and  intimately 
mixed  with  the  air  in  which  it  is  to  'burn.  The  hot  vaporizer  walls  facili- 


LOW  COMPRESSION  ENGINES 


467 


tate  ignition  and  subsequent  combustion,    in  this  way  moderate  pressures 
are  employed,  and  the  high  efficiency  of  the  Otto  cycle  attained. 

The  vaporizer,  with  its  large  heated  area,  makes  nigh  pressure  in 
the  combustion  chamber  unnecessary.     The   compression  pressure   need 


HINOW  H3d  savnoa 


not  exceed  about  300  Ibs.  per  square  inch.  Use  of  the  uncooled  vapor- 
izer enables  the  De  La  Vergne  engine  to  obtain  as  good  results  as  those 
obtained  with  a  pressure  of  only  half  as  great  as  that  used  on  high  com- 
pression engines. 


468  LOW  COMPRESSION  ENGINES 

THE   WYGODSKY   SYSTEM    OF   OIL   ENGINES 

The  Wygodsky  Self-Starting  Crude  Oil  Engine  is  manufactured  by 
the  Baltimore  Oil  Engine  Company,  Baltimore,  Md.,  in  several  types,  two 
of  which  are  described  hereinafter.  One  is  a  horizontal,  four-cycle, 
heavy-duty,  type  for  medium  powers,  and  the  other  is  a  two-cycle  type  for 
large  powers. 


Wygodsky  Self-Starting  Oil  Engine.     Horizontal  Type  of  Engine  Showing 
Arrangement  of  Parts. 

The  horizontal  four-cycle  engine  is  illustrated  in  figures  B  and  D. 

The  principal  feature  of  the  engine  is  the  airless  atomizer,  J.5,  which 
in  conjunction  with  the  ignition  element,  J.I,  the  special  fuel  oil  torch, 
OT,  the  air-foot-pump,  AP,  and  the  special  flywheel  locking  device,  K, 
makes  the  engine  selfnstarting,  without  storing  of  compressed  air,  and 
without  the  use  of  electrical  devices.  These  elements  are  described 
below. 

The  airless  atomizer  produces  the  atomization  of  the  fuel  by 
hydraulic  pressure  which  is  developed  by  means  of  fuel  pump  L  (figure 
G.A.12)  which  is  under  direct  action  and  control  of  the  governor,  M.  The 


LOW  COMPRESSION  ENGINES 


469 


I 


470 


LOW  COMPRESSION  ENGINES 


principal  part  of  the  'atomizer  is  the  spray  cone,  J.10,  the  conical  surface 
of  which  is  covered  with  'spiral  grooves  of  diminishing  sections,  and  is 
placed  against  a  similar  conical  surface  in  nozzle,  J.15.  The  throat  of 
this  nozzle  is  closed  >by  a  needle  valve,  J.16,  which  is  movable  in  con- 
junction with  plunger,  J.14.  This  plunger  has  a  very  snug  fit  in  sleeve, 
J.18,  and  is  loaded  by  means  of  spring,  J.7.  The  pressure  of  the  oil 
within  the  atomizer  due  to  the  action  of  the  fuel  pump,  L,  will  move  the 
plunger,  J.14,  against  the  'spring  and  will  carry  along  the  needle  valve, 
J.16,  thus  opening  the  nozzle.  Oil  will  then  circulate  through  the  spiral 
grooves  of  the  spray  cone,  J.10,  with  accelerating  motion  due  to  the  de- 
creasing sections  of  the  spiral  grooves,  and  will,  set  up  in  the  throat  of 
the  nozzle  a  small  column  of  oil  in  high  rotary  motion.  This  column 
when  released  from  the  nozzle,  breaks  up  into  a  very  fine  mist  due  to 
centrifugal  action.  As  soon  as  the  fuel  pump  plunger  stops  advancing, 


Governor  and  Oil  Pump  of  the  Wygodsky  Self-Starting  Oil  Engine. 

the  pressure  in  the  sprayer  drops  instantly  and  the  spring,  J.7,  shuts  the 
nozzle  rapidly  and  prevents  dribbling.  This  arrangement  permits  the 
breaking  up  of  the  smallest  quantities  of  oil  into  very  fine  mist  without 
any  dribbling.  To  give  any  idea  of  the  effectiveness  of  the  spray,  it  may 
be  mentioned  that  the  column  of  oil  in  the  throat  of  the  nozzle  produces 
about  1,100,000  R.P.M.,  and  the  initial  velocity  of  the  particles  of  oil 
which  issue  from  the  nozzle  is  about  270  feet  per  second.  Any  fuel,  even 
with  a  high  flash  point,  easily  ignites  when  cold  if  atomized  by  means  of 
this  sprayer. 

The  engine  works  with  a  moderate  compression  pressure  of  300  Ibs. 
per  square  inch,  and  to  obtain  the  starting  ignition  while  the  engine  is 
cold,  a  temporary  ignition  device,  J.I,  figure  G.A.10,  is  used.  This  ignition 
device  is  a  hollow  ring  and  is  totally  enclosed  within  the  water  cooled 


LOW  COMPRESSION  ENGINES 


471 


472 


LOW  COMPRESSION  ENGINES 


combustion  chamber.  No  hot  surfaces  are  exposed  to  the  outside  of  the 
engine,  but  the  heated  surfaces  are  entirely  inside  tlie  combustion  cham- 
ber, so  it  is  evident  that  this  is  not  a  hot  bulb  engine.  This  device  has 
two  apertures  which  connect  the  inside  of  this  hollow  ring  with  two 
channels  in  the  waiter  jacketed  cover  projecting  through  the  cylinder 
head.  One  channel  is  for  the  introduction  of  the  oil  torch,  G.A.13,  and 
the  other  channel  serves  for  the  escape  of  the  products  of  combustion. 


General  Arrangement  of  Air  Pump  of  Wygodsky  Self-Starting  Oil  Engine. 

This  torch,  G.A.  13,  connected  to  the  foot-air-pump  G.A.  15,  which 
furnishes  air  to  it,  is  of  an  interesting  construction.  The  torch  can 
burn  the  same  fuel  as  the  engine  and  the  reservoir  can  be  refilled 
while  the  torch  is  burning,  as  there  is  no  pressure  on  the  oil  whatever. 
The  torch  does  not  require  any  fpre-heating  for  it  starts  to!  .burn  as  soon 
as  the  foot  pump  develops  25  Ibs.  pressure  in  a  reservoir  of  about  3% 
gallons  capacity. 

The  next  element  of  self-starting  is  the  locking  device,  K,  Figure  B. 
This  locking  device  consists  of  a  toggle  mechanism,  K6,  7,  8  and  9.  It  is 


Sectional  View  of  Sprayer  of  the  Wygodsky  Self-Starting  Oil  Engine. 


LOW  COMPRESSION  ENGINES  473 

pivoted  in  two  points,  K17  and  K18.  It  is  loaded  toy  means  of  spring  K19. 
The  position  of  ti£s  mechanism  as  shown  in  figure  OB,  is  that  when  the 
engine  is  ready  for  starting.  The  dog,  K9,  is  then  inserted  in  the  slot 
of  the  flywheel.  This  keeps  the  flywheel  in  starting  position,  in  which 
position  the  crankshaft  is  about  60  degrees  above  its  inner  dead  center 
on  the  firing  stroke.  Sectional  view,  Fig.  D,  shows  piston  and  crank- 
shaft in  starting  position. 

The  process  of  self-starting  is  as  follows: 

The  foot-pump,  AF,  is  given  several  strokes  and  the  .torch,  OT,  is 
ignited  by  a  lighted  match,  the  pumping  being  continued  for  about  two 
minutes,  in  the  course  of  which  time  the  ignition  tube  -becomes  hot 
enough  to  ignite  the  spray.  After  the  ignition  device  has  been  made  hot 
enough,  some  of  the  air  from  the  foot-pump  is  admitted  into  the  combus- 
tion chamber  with  the  double  purpose  of  making  sure  that  the  combus- 
tion chamber  is  filled  with  pure  air  and  also  to  have  the  air  pressure 
raised  to  atoout  40  Ibs.  The  spring  of  the  above  mentioned  locking  de- 
vice is  made  strong  enough  to  hold  the  flywheel  in  the  starting  position 
so  that  the  flywheel  will  not  toe  released  until  there  is  enough  pressure 
behind  the  piston  to  start  the  engine  running.  This  pressure  is  produced 
by  manually  operating  the  fuel  pump.  This  action  produces  a  spray 
through  the  atomizer  into  the  comtoustion  chamber.  This  spray  being 
produced  in  the  proximity  of  the  ignition  tube  and  in  an  atmosphere  of 
40  Ibs.  pressure,  an  explosion  follows  which  is  strong  enough  to  turn  the 
dog  of  the  locking  device.  This  locking  device  then  collapses  as  shown 
by  the  dotted  lines  in  figure  B,  and  the  engine  begins  to  work  normally. 
The  torch  then  goes  out  by  itself,  and  the  lubrication  starts  automatically 
so  that  no  valves  have  to  be  operated.  The  starting  cycle  gives  a 
M.E.P.  atoove  100  pounds  per  square  inch,  so  that  the  engine  starts  with 
a  load  of  approximately  50  per  cent  of  its  rated  capacity.  The  engine 
is  also  provided  with  special  means  for  self-cleaning.  By  means  of  a 
special  device  the  engine  ejects  automatically  any  solid  or  liquid  deposit 
that  may  find  its  way  into  the  combustion  chamber.  The  same  feature 
is  utilized  for  stopping  the  engine  approximately  in  its  starting  position. 
The  M.E.P.  ototainable  in  this  engine  is  116  pounds  per  square  inch. 

After  the  starting  of  the  engine  has  been  explained,  the  operation  of 
same  is  easily  understood  toy  anyone  familiar  with  a  four-cycle  oil  engine. 
The  governor  which  is  explained  below  acts  directly  on  the  plunger  of  the 
fuel  pump  and  injects  the  oil  slightly  'before  the  end  of  the  compression 
stroke. 

The  governor  of  an  oil  engine  is  one  of  the  most  important  elements. 
Many  a  good  oil  engine  proved  to  be  a  failure  on  account  of  poor  govern- 
ing. The  method  of  governing  in  this  Wygodsky  oil  engine  is  the  variable 
stroke  method;  with  timing  of  the  beginning  of  injection,  constant;  and 
the  end  of  injection,  variatole,  i.  e.,  sooner  or  later,  according  to  the  load 
on  the  engine.  The  governor  of  this  engine  comprises  a  governor  proper, 
as  well  as  the  governing  mechanism,  all  enclosed  in  one  casing.  The 
governor  is  also  free  of  reaction  from  the  governed  mechanism  and 


474 


LOW  COMPRESSION  ENGINES 


therefore  it  permits  running  the  governor  at  comparatively  slow  speeds, 
viz.,  the  -speed  of  the  crankshaft.  The  governor  and  pump  are  repre- 
sented in  figure  G.A.12,  in  which  L.38  is  the  plunger,  iL.48  is  the  suction 
valve,  and  L.15  the  delivery  valves.  The  governing  mechanism  consists 
of  the  cam  lever  M.23,  which  is  pivoted  eccentrically  in  the  governor 
casing.  This  lever  is  provided  with  a  cam  face  which  acts  directly  on 
roller,  L.12,  of  the  fuel  pump.  This  cam  face  is  an  arc  of  a  circle  de- 
scribed from  its  pivot  center.  The  position  of  this  cam  lever  is  deter- 
mined by  means  of  a  finger,  M.9,  which  finger  is  attached  to  a  swinging 
lever,  M.ll,  which  is  pivoted  at  M.12.  This  finger  acts  between  a  special 
inner  face  of  the  governor  case  and  a  curved  face  of  the  cam  lever;  the 
inner  face  of  the  case  is  an  arc  of  a  circle  described  from  M.12  as  a  centre 
and  the  curve  of  the  cam  lever  is  figured  out  so,  that  the  tangents  of 


Four-Cycle  Single  Cylinder  Heavy  uuiy  Wygodsky  Self-Starting 
Crude  Oil  Engine. 

these  two  curves  and  finger,  M.9,  form  an  angle  which  is  less  than  the 
angle  of  friction  corresponding  to  the,  materials  used.  The  idea  is  that 
when  the  governor  runs  in  a  counter-clockwise  direction  the  reaction 
from  roller  L.12  on  the  cam  lever,  M.23,  tends  to  jam  the  finger,  M.9, 
without  pushing  same  in  either  direction.  It  should  be  mentioned  that 
the  link  M.ll,  by  means  of  link,  M.8,  is  connected  to  one  of  the  governor 
weights,  M.2.  There  is  also  another  governor  weight,  M.3,  which  is 
situated  in  a  diametrically  opposite  direction  of  M.2,  and  is  connected  to 
same  by  means  of  a  connecting  link,  M.13,  in  such  a  manner  as  to  give 
both  weights  a  similar  motion.  These  two  weights  furnish  a  centrifugal 
force  of  the  governor  when  same  is  rotating.  The  centrifugal  force  is 
furnished  by  spring  M.20,  which  is  arranged  to  permit  an  adjustment  of 
its  length,  as  well  as  an  adjustment  of  its  tension.  As  mentioned  before, 


LOW  COMPRESSION  ENGINES 


475 


finger  M.9  being  situated  in  an  angle  which  is  less  than  the  friction 
angle  will  not  transmit  any  reaction  to  the  weights  of  the  governor.  The 
cam  face  of  the  governor  lever,  'being  an  arc  of  a  circle,  will  have  the 
same  point  of  intersection  with  the.  outer  periphery  of  the  governor  cas- 
ing irrespective  of  the  position  of  the  cam  lever.  This  naturally  will  give 
a  constant  point  for  the  beginning  of  the  injection  of  the  fuel. 

The  whole  engine  is  built  on  the  interchangeable  principle,  and  for 
easy  operation,  so  that  no  expert  labor  is  required.  This  feature  makes 
it  a  suitable  engine  for  any  part  of  the  country,  as  well  'as  for  export 
purposes. 


Two-Cycle  Wygodsky  Self-Starting  Crude  Oil  Engine.      The  economy  per- 
formances compare  well  with  the  best. 


Two  Cycle  Type 

The  principle  of  the  Wygodsky  Self-starting  Crude  Oil  Engine  is  also 
utilized  in  a  two  cycle  type  engine. 

This  two  cycle  Diamond  Type  engine  has  been  designed  for  engines 
of  higher  horsepower,  and  also  for  an  engine  which  is  much  simpler  in 
the  design  and  manufacture  than  any  other  engine  known. 

The  transfer  of  gases  is  accomplished  through  ports,  which  arc  con- 
trolled by  the  working  pistons.  It  is  a  modified  opposed  piston  engine, 
which,  while  preserving  all  the  advantages  of  such  a  system,  at  the  tvarne 
time  eliminates  its  disadvantages,  such  as  multiplicity  of  crankpins, 
connecting  rods,  large  dimensions,  etc. 


476 


LOW  COMPRESSION  ENGINES 


LOW  COMPRESSION  ENGINES  477 

This  engine  works  with  the  previously  described  patented  hydraulic 
sprayer,  without  compressed  air,  and  has  a  low  operating  pressure.  It 
is  easily  started  from  the  cold  in  about  three  minutes,  and  uses  very 
little  compressed  air,  when  starting  with  compressed  air, '  and  still  less 
when  starting  with  the  self-starting  mechanism,  which  has  been  de- 
scribed in  connection  with  the  stationary  engine.  The  camshafts  are 
eliminated,  besides  valves,  levers,  brackets,  rollers,  etc.  The  who]?  en- 
gine is  just  a  mass  of  reciprocating  pistons  and  revolving  crankpins. 

It  'has  been  recognized  of  late  that  an  oil  engine,  to  give  a  large 
output  of  power,  must  necessarily  'be  of  the  two-cycle  type.  Although 
the  opposed  piston  principle  has  been  used  many  years  ago  in  gas  and 
gasoline  engines,  its  adaptation  for  oil  engines  has  been  perfected  only 
recently.  This  system  primarily  permits  perfect  scavenging,  eliminates 
air  and  exhaust  valves,  as  well  as  mechanism  for  oiperating  same,  and 
also  eliminates  the  cylinder  head,  which  is  a  very  weak  part  in  any  oil 
engine. 

The  two  pistons,  which  operate  in  a  common  combustion  chamber, 
permit  the  development  of  double  the  power  with  the  same  mechanism 
for  the  introduction  of  fuel.  This  has  very  many  attractive  features,  al 
though  the  way  it  has  been  carried  out  up  to  this  time,/  has  many  great 
mechanical  drawbacks.  For  instance,  to  operate  the  two  pistons  it  is 
necessary  to  have  three  crankpins  and  three  connecting  rods,  besides  all 
the  appurtenances  that  go  with  same.  Moreover,  it  is  practicable  to  put 
only  two  bearings  between  said  crankpins,  and  therefore  the  crankshaft 
has  to  be  made  of  very  heavy  sections,  and  naturally  the  crankshaft  is 
expensive.  Furthermore,  the  width  and  length  of  such  an  engine  is  very 
great,  and  therefore  very  costly  to  produce.  It  will  be  seen  in  the  en- 
gine described  below  that  only  one  crankpin  is  required  for  two  pistons 
instead  of  three;  furthermore,  a  group  of  four  pistons  requiring  two 
crankpins  are  located  in  one  plane  and  are  operated  by  two  crankpins 
located  in  two  separate  crankshafts.  The  regular  opposed  piston  system 
requires  6  crank  pins  for  four  pistons.  From  the  above  the  compactness 
and  small  dimensions  of  the  Wygodsky  engine  is  easily  seen.  This 
method  readily  permits  the  concentration  of  larg'e  powers  in  a  small 
space. 

Figure  3  shows  a  sectional  view  of  the  engine.  As  intimated  before, 
this  engine  is  provided  with  two  crankshafts;  one  upper  crankshaft,  1, 
and  lower  crankshaft,  1A.  They  are  connected  toy  means  of  a  special  link 
motion  so  that  they  operate  in  synchronism  and  in  opposite  sense.  Each 
cranfcpin  is  operated  toy  two  connecting  rods:  one  left-hand  connecting 
rod,  2,  which  is  forked,  and  the  other  right-hand,  2A,  operates  within 
the  fork  of  the  former.  The  pistons,  3,  are  operated  by  said  connecting 
rods,  so  that  each  upper  and  lower  piston  work  symmetrically.  The  cyl- 
inder structure  is  made  in  a  V  shape  and  this  permits  accommodating 
two  such  structures,  one  on  each  side  of  the  crankshafts  plarie.  These 
two  cylinder  structures  give  the  section  of  the  engine  a  "diamond  shape." 

In  figure  3,  four  (4),  indicates  the  spray  box  to  which  is  attached  the 


478 


LOW  COMPRESSION  ENGINES 


starting  ignition  ring,  5,  and  the  atomizer  is  introduced  through  aperture 
6;  both  essentially  the  same  as  in  the  stationary  four-cycle  engine. 

The  cylinder  proper,  7,  is  a  water  jacketed  "elbow,"  the  lower  leg 
of  which  is  slightly  shorter  than  the  upper  leg.  The  reason  for  this 
will  be  explained  later.  This  cylinder  is  designed  to  withstand  the  full 
pressure  of  the  working  cycle.  To  the  upper,  as  well  as  the  lower  flanges 
of  said  cylinders,  7,  are  attached  guide  cylinders,  8,  which  receive  the 
pistons  after  the  ports  have  been  uncovered.  These  guide  cylinders  are 
provided  wiith  port  belts,  9,  which  extend  all  around  the  piston,  and  the 
contour  of  which  is  made  to  conform  to  that  of  the  bottom  of  the  piston. 
This  belt,  9,  is  in  communication  with  passages,  10,  and  10A;  the  former 
serving  as  air  manifolds,  and  the  latter  being  exhaust  manifolds.  Thus 
we  have  two  air  manifolds,  and  two  exhaust  manifolds.  These  manifolds 
are  provided  with  special  flanges  and  when  such  cylinders  are  assembled 


Fuel  Pump  Bracket  of  Two-Cycle  Wyyodxky  Keif-Starting  Crude  Oil  Engine. 


in  the  engine  they  register  with  each  other  and  form  continuous  pass- 
ages for  either  air  or  exhaust.  They  are  kept  air  tight  by  means  of  a 
special  packing  device.  Thus  no  special  air  or  exhaust  manifolds  are 
required. 

It  will  be  noticed  that  the  bottoms  of  the  pistons  are  provided  with 
flats  which  are  mutually  parallel  in  each  cylinder  structure  and  thus  ipro- 
vide  a  combustion  space  which  is  much  different  than  the  wafer  shape 
which  we  see  in  the  regular  opposed  piston  engines  or  even  in  the  regular 
Diesel  engines. 

Figure  5  is  a  plan  view,  and  figure  6  is  a  front  elevation  of  the  engine. 
On  the  left  hand  side  of  isaid  figures,  11,  and  11A  indicate  the  two  double 


LOW  COMPRESSION  ENGINES 


479 


acting  scavenging  pumps,  which  by  means  of  tubular  member,  12,  are 
connected  to  the  two  air  manifolds,  10,  into  which  these  two  pumps  dis- 
charge the  air.  The  four  pistons  of  said  pumps  are  operated  by  means 
of  four  crankpins,  two  of  which  are  located  in  each  of  the  two  crank- 
shafts respectively.  The  same  crankpins  are  utilized  for  the  link  mechan- 
ism which  connects  both  crankshafts  so  as  to  make  them,  operate  in 
opposite  directions;  thus  the  crankpins  serve  a  double  purpose,  i.  e.,  oper- 


General  Arrangement  of  Baltimore  Oil  Engine.      Vertical  Type. 


ating  the  four  pistons  of  the  scavenging  pumps  as  well  as  the  connect- 
ing mechanism  between  the  two'  crankshafts.  Owing  to  automatic  air 
valve  of  a  special  construction  these  same  scavenging  pumps  also  serve 
for  starting  and  reversing  the  engine  by  means  of  compressed  air.  The 
different  parts  of  the  pumip  are  connected  by  means  of  pipes  to  the  air 
distributing  mechanism,  14,  which  is  actuated  by  means  of  hand  lever, 


480  LOW  COMPRESSION  ENGINES 

15.  This  hand  lever  when  pushed  forward  starts  the  engine  in  a  forward 
direction;  when  pushed  'backward  it  starts  the  engine  in  a  backward  or 
reverse  direction.  When  left  alone  the  lever  automatically  returns  to 
its  neutral  position  and  automatically  cuts  off  the  air  supply  from  the 
tank. 

The  movement  of  said  lever,  15,  has  the  effect  of  automatically  con- 
verting the  scavenging  pumps  into  working  cylinders  directing  the  air 
into  the  necessary  chambers  to  effect  the  movement  of  the  pistons  in  the 
desired  direction  and  finally  exhausting  expanded  air  into  any  of  the 
working  cylinders,  scavenging  same  through  the  usual  ports.  After  that 
the  air  escapes  through  the  regular  exhaust  pipe.  This  system  of  utilizing 
the  compressed  air  has  the  advantage  of  securing  pure  air  for  the  com- 
bustion and  also  does  away  with  the  necessity  of  providing  extra  mufflers 
to  take  care  of  the  air  exhaust.  Needless  to  say  that  the  complicated 
controls  which  are  met  with  in  the  starting  mechanism  of  the  Diesel 
engine  are  completely  done  away  with.  It  also  must  be  mentioned  that 
this  engine  besides  ease  of  starting  and  reversing,  uses  very  little  air 
to)  effect  these  actions.  It  is  necessary  just  to  give  about  one-third  of  a 
revolution  to  start  the  engine  spinning  in  any  desired  direction;  this  is 
due  to  the  above  described  patented  ignition  device. 

As  mentioned  before,  the  engine  has  no  camshafts.  The  whole  oper- 
ating mechanism  is  assembled  on  one  bracket,  shown  in  the  upper  left 
hand  corner  of  figure  6,  in  which  16  shows  four  fuel  pumps;  four  similar 
pumps  are  on  the  other  side.  Each  pump  is  connected  to  its  respective 
combustion  chamber.  All  fuel  pumps  are  operated  by  a  small  crankshaft, 
17,  which  is  similar  to  the  main  upper  crankshaft  and  is  attached  to 
same  by  means  of  a  special  clutch,  18,  which  permits  a  certain  angular 
movement  between  the  two  crankshafts.  The  action  of  each  pump  may 
be  tested  by  means  of  lever  19.  Lever  20  is  for  regulating  the  speed  of 
the  engine,  and  when  raised  raises  the  .speed  and  when  lowered  reduces 
the  speed  of  the  engine.  Governor,  21,  regulates  the  maximum  speed  of 
the  engine. 

For  self-starting,  the  engine  is  provided  with  a  locking  device  as 
described  in  connection  with  the  stationary  engine.  Parts  of  this 
locking  device,  22,  are  indicated  on  figures  1  and  6. 

From  the  description  above,  it  can  be  easily  seen  that  the  system 
permits  a  large  concentration  of  power  pistons  in  a  small  space,  so  it 
is  not  surprising  that  this  engine  is  very  light  in  weight  (35  Ibs.  per 
B.H.P.),  although  the  pistons  speed  is  only  about  750  feet  'per  minute. 

For  operating  the  engine,  two  methods  of  starting  will  be  described: 
one,  the  air  starting,  the  other,  "Self  Starting." 

It  is  recommended  in  regular  practice,  for  starting  as  well  as  re- 
versing, to  use  the  air  device,  while  the  "self  starting"  is  -utilized  in 
emergency  cases  when  for  some  reason  or  other  there  is  no  air  available. 

Before  starting,  the  ignition  tubes,  6,  are  heated  by  means  of  special 
torches  inserted  in  the  lower  funnel  of  spray  box,  4.  This  heating  is 
continued  for  about  two  minutes.  After  this,  air-starting  le