EPA/AA/CTAB-89-02
                         Technical  Report
             Conversion of MethanoI-Fueled 16-Valve,
            4-CyUnder Engine to Operation On Gaseous
                 2H2/CO Fuel - Interim Report II
                               by
                      Gregory K.  Piotrowski
                          James Martin
                           March 1989
                             NOTICE

     Technical  Reports  do not  necessarily  represent  final  EPA
decisions or  positions.   They  are intended to present technical
analysis  of   issues  using data  which are  currently available.
The purpose  in  the release of such reports is to facilitate the
exchange  of  technical  information and  to  inform the  public of
technical developments which may form the basis for a final EPA
decision, position or regulatory action.

              U.  S.  Environmental  Protection Agency
                   Office of Air  and Radiation
                    Office of Mobile Sources
              Emission Control  Technology Division
           Control Technology and Applications Branch
                       2565 Plymouth Road
                   Ann Arbor,  Michigan  48105

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        UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

                     ANN ARBOR. MICHIGAN  48105
                                                        OFFICE OF
                                                      AIR AND RADIATION
 APR 24 1989

MEMORANDUM
SUBJECT:


FROM:


TO:
           Exemption From  Peer and  Administrative  Review
                                    f^
           Karl H. Hellman,  Chief
           Control Technology and Applications  Branch

           Charles L. Gray,  Jr., Director
           Emission Control  Technology  Division
     The attached report entitled,  "Conversion  of  Methanol-
Fueled  16-Valve,  4-Cylinder  Engine  to  Operation  On  Gaseous
2H2/CO   Fuel   -   Interim   Report   II,"    (EPA/AA/CTAB/89-02)
describes  progress  to  date  on  a  project  to  convert  a  Nissan
CA18DE  engine  previously  modified  for  operation  on M100  neat
methanol   to  operation    on   dissociated   methanol   (2H2/CO)
gaseous  fuel.   This engine  has  been  operated,  on  both M100  and
simulated  dissociated  methanol  (hydrogen  and  carbon  monoxide)
gaseous fuels.   This  report describes the.  modifications  made to
the  engine  and   summarizes  the   results   of  testing  to  date.
Further  work  on  this  project will  be  described  in  a  future
technical report.

     Since this  report  is  concerned,  only with  the  presentation
of data and  its  analysis  and does not involve matters  of  policy
or   regulations,   your   concurrence  is   requested  to   waive
administrative review  according  to  the  policy  outlined  in  your
directive of April 22, 1982.
   Concurrence
                                               Date
               _^ _         _
               cfiTrles L. Gray, j/.,'.Dir., ECTD
Nonconcurrence :
                                                Date
               Charles L. Gray, Jr., Dir., ECTD

cc:  E. Burger, ECTD

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                        Table of Contents

                                                          Page
                                                         Number
 I .   Summary	    1
 II.  Introduction   	    2
 III. Description of Test Engine	    3
 IV.  Modifications For 2H2/CO Fuel Operation  	    4
     A.    Engine Modifications   	    4
     B.    Fuel System Modifications   	    9
V.   Exhaust Analysis  	   10
VI.  Results from Testing	   11
VII. Project Highlights To Date	   17
VI11.Future Effort	   18
 IX.  Acknowledgments	   19
X.   References	   19
APPENDIX A - Test Engine Specifications -	A-1
             M100 Fuel Operation
APPENDIX B - Air/Fuel Ratio Calculation With   	  B-1
             2H2/CO Fuel

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 I.    Summary

      The  work described in this  report  concerns the  conversion
 of   a  16-valve,  4-cyUnder   light-duty  automotive   engine   to
 operation on  a  mixture of  hydrogen  (H2)  and  carbon monoxide
 (CO)  gaseous fuel.   This  engine  will  be evaluated to determine
 the  difference  in  emission  levels  and  lean  limit  operation
 between two different  fuels:   M100 neat methanol and simulated
 dissociated  methanol  gaseous  fuel   (2H2/CO).   The  engine will
 eventually  be  used  as a  test  bed  for  a  practical,  onboard
 methanol  dissociation fuel system.

      Modifications  made  to  the   test  engine   to  enhance   the
 characteristics  of  2H2/CO  fuel are  discussed  in  this  report.
 A  description of  the  CA18DE  test  engine  modified for  use  on
 M100  neat methanol by Nissan Motor Co., LTD,  is  also included.

      The  engine  ran   very  smoothly  at  idle  and  under  load
 conditions  with  the   simulated   dissociated  methanol    2H2/CO
 fuel.   Visible engine  vibration from gaseous fuel operation  was
 noticeably  reduced  from  levels  experienced with  the   engine
 operating on  liquid methanol fuel.

      The  test engine  was  able to  operate  very  lean with  the
 2H2  + CO fuel.   The  air/fuel  (A/F)   ratio  was  computed  to  be
 14.8:1  at no  load,  625  rpm  and 26.5:1  at no  load,  1500 rpm.
 When  10.3 BMP was being produced  (27.1  ft-lb torque,  2000  rpm),
 the  A/F ratio dropped  to  11.9:1.   All  of  these A/F values  are
 lean  when  operation   on   2H2   +  CO   is  concerned,   since   the
 stoichiometric A/F  ratio  is  the  same as  it is  for  methanol,
 6.4:1.   The  leanest  A/F  ratio 26.5:1,  is  much closer  to  the
 stoichiometr ic A/F  ratio  for  H2  (34:1) than  it  is to  that  of
 CO (2.5:1)  so the operation  seems to  be  enhanced by  the  H2   in
 the gaseous fuel.

     A  direct comparison  of  emissions test  results from  the
 engine  when  it  was  alternately  fueled  with M100 and  2H2/CO
 fuels  is  not  possible  at  this time.  The testing with M100 fuel
 utilized  a  catalytic  converter  in  the exhaust  stream  while
 2H2/CO  fuel  results  are  engine-out  emissions.   The  2H2/CO
 fuel   emissions  test   results   may  vary  substantially  between
 tests  because the  limited amount  of  2H2/CO fuel  in  the  "T"
 cylinder storage  bottles did not permit  starting and  warming  to
 steady-state conditions prior to testing.

     Additional emissions  testing  at  various  engine  speed/load
operating conditions will  be conducted  to  better  characterize
 the emissions profile of this  engine when operated on both M100
and   dissociated  methanol.     A/F   ratio   under   these   test
conditions will also be determined.

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                               -2-


 11.   Introduction

      Section  211  of  the Clean  Air Act  [1]  requires  the U.S.
 Environmental  Protection Agency  (EPA)  to play a key  role  in  the
 introduction  of  new motor vehicle fuels.  EPA studies  [2] have
 suggested   that  methanol  stands  out   from  other   alternative
 transportation  fuels  from  an  environmental  perspective.    The
 use  of alcohol  fuels can also  play a  significant  role  in  the
 reduction  of   the  foreign trade  deficit and  aid  the  security
 interests  of  the  United  States  by  reducing U.S.  dependence on
 imported petroleum.[3]

      Methanol  may  be catalyt ical ly  decomposed  to  H2  and  CO
 gases according  to the reaction:

      CH3OH( , ,	 2H2(g) + C0
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                               -3-
      In order to assist this program  at  Ricardo,  a project was
 begun  to  convert   a  methanoI-fueled  engine  to  operation   on
 2Hz/CO gaseous  fuel.   The  goal  of  this  project was  to modify
 a  16-valve,  4-cyUnder  light-duty automotive  engine  for use
 with  2H2/CO  gaseous  fuel  and  to  evaluate  this  engine  using
 two fuels:

      1.     2H2/CO bottled  gas   (in  the  same  molar proportions
            as dissociated methanol,  2H2/CO); and

      2.     M100  neat methanol (liquid  fuel).

      The  criteria  for  evaluation was  the engine's  ability  to
 run  without   driveability  problems   at  the  lean  limit   of
 operation and emission  levels  over several  steady-state  speed
 and  load conditions.   Once the conversion and  initial   testing
 were completed,  the engine was  to be  used  as  a  test engine for
 the  onboard  dissociator  under  development  at   Ricardo.   This
 report contains  a  summary of   the  work  to  date  performed   to
 facilitate  conversion  to the gaseous  fuel, as  well  as  results
 from initial  testing of the engine  on both  liquid and gaseous
 fuels.

 III.  Description  of  Test Engine

      The  test engine used  for this  project was  a Nissan CA18DE
 engine.   This  engine   is  an   in-line,  4-cyUnder,  1.8-liter
 capacity  powerplant.  The  valve arrangement  is a  4-valve per
 cylinder  configuration,  consisting  of   two   intake  and  two
 exhaust  valves per  cylinder.    The  valves  are  operated  by two
 overhead  camshafts,  one each for  the   intake  and  exhaust  side.
 The   stock   gasoline-fueled  version   of  this   engine  has  a
 compression ratio of 10.0  and  a standard  compression pressure
 of  14.0 kg/cm2 at 350 rpm.

      A CA18DE engine was modified by  Nissan  Motor Company, LTD
 to  better utilize the  qualities of  M100 neat methanol,  rather
 than  unleaded gasoline.   Metal   from the  bottom  of  the head was
 shaved  in  order  to  increase  the   compression  ratio to   11.0.
Standard  compression  pressure   was  raised  to  16.5  kg/cm2   at
350  rpm by this modification.  A detailed description of engine
 specifications  from this  engine  after  the modifications  made
 for methanol compatabiIity  is given  in Appendix A.

      Two  external control devices  were also added  by  Nissan  as
modifications  to  the   stock  engine.   The  first,  an  air/fuel
mixture control  device, varied  air/fuel   ratio  by controlling
 fuel   injection  quantity.   Excess   air   ratio  (lambda)  may   be
varied  from 0.5  to  2.0  through  the use  of this  control.   The
second device  varied ignition  timing between  0  before top dead
center (BTDC)  and 54 BTDC.

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                               -4-
     Following   the   conversion   from   gasoline   to   M100  fuel
operation,  Nissan  Motor Company,  LTD  lent this  engine  to  the
U.S. EPA for use with methanol fuel research efforts.

IV.  Modifications For 2H2/CO Fuel Operation

     Several  modifications  to  the  engine  were  necessary  in
order  to  operate  on  2H2/CO  fuel;   these  modifications  are
discussed below.   Included also  is a discussion  of the bottled
gas fueling system.

     A.    Engine Modifications

     Dissociated methanol  product gas   is  a mixture  of H2  and
CO  gases in  the  molar ratio  2H2/CO.   We  did  not  possess  a
methanol  dissociation   system   capable  of   generating   the
necessary quantities  of gaseous  2H2/CO fuel  at  the  time  work
on this  project  was  begun.   The  engine  was therefore  tested  on
a bottled gas  mixture  of  2H2/CO;  several  bottles of 66 volume
percent  H2  and  34 volume  percent CO  were  obtained  from  Linde
Gases,    Inc.  to  simulate  the  products  of   the dissociation
reaction.

     The Nissan  CA18DE  engine utilizes  a  4-valve per  cylinder
vaI vet rain  configuration;   both   the  stock  gasoline   and  M100
methanol modified  versions utilize two  intake  and  two  exhaust
valves  per  cylinder.    This  arrangement was  modified   to  allow
for admission of  air  to the  cylinder  through one intake  valve
only;  the second intake valve supplied  the gaseous  fuel.   The
exhaust-side valve scheme was not modified  (Figure 1).
                            FIGURE 1
                         VALVE SCHEME

                   2H2/CO FUEL CONVERSION

                     NISSAN CA18DE ENGINE

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                               -5-
      The  advantages  of  structuring the  intake  process this  way
 are threefold.   First,  air  flow   into  the engine  may  be  less
 restricted   if  the   fuel,  already  in   the   gaseous   state,   is
 introduced  into only  one  of  the  intake  runners.   Second,  there
 may  be   less   chance of   flashback  and   a   resulting manifold
 ignition  if fuel  exclusively,   and not  a  combustible fuel/air
 mixture,  is  introduced  at an  intake valve.   Finally, fuel  may
 enter  the  combustion chamber  at  the  designer's  discretion,
 rather  than at the  same  time  the air needed  for combustion  is
 admitted.

      It was necessary  to alter the  fuel  and air intake system  in
 order  to allow for   the admission of gaseous  fuel  only  through
 one of  the   intake   valves.   An   intake   air  control  assembly
 encloses  the  swirl  control  valves  and   is  situated  between  the
 intake manifold and  the combustion chambers on the liquid-fueled
 engine.   This  assembly controls   the  air  flow   so  that  it  is
 through one  intake runner  and/or through both  intake  runners  as
 necessary.   This  is  to control  in-cyUnder charge motion on  the
 liquid-fueled  engine.  The  control  valve  slide and actuator  were
 disassembled and the  swirl control  valves  removed.   The  runners
 through  the   valve   assembly  that  contained  wells  for   fuel
 injectors were welded shut approximately  1/2-inch upstream  from
 the well holes.  These seals  prevent the  admission of  air to  the
 ports through  which  the gaseous fuel passes.

     The hole  in the assembly left by the  power  valve slide was
 sealed to  prevent leakage  of fuel and  air between  runners.  A
 metal  impregnation  technique was  used  to  seal the  holes.  The
 sealed holes were  then coated with a layer of epoxy.

     Fuel  injectors   are  not  used  to  feed   the  gaseous state
 fuel.  The  rail  and  the  individual  injectors were  removed and
 3/8-inch inside diameter stainless  steel  pipe  fittings were  used
 in  their  place.  The  stainless steel  fittings were threaded and
 the insides of  the aluminum injector wells  were  then  threaded  to
 accept the fittings.

     Stock dual-overhead camshafts were used  by Nissan to equip
 the CA180E engine  modified for  use on M100 methanol.   A  drawing
 of  the stock   intake-side  camshaft  is presented  in Figure  2.   It
 was necessary  to  redesign the  intake  side   lobes  in order  to
 accommodate the  air/fuel induction strategy depicted  in Figure 1
 for the gaseous  fuel.  Figure 2 also presents the air/fuel  lobe
 scheme for the  intake camshaft when operated on gaseous fuel.

     Nissan  reported  that  the  valve  timing  events  for  the
M100-modified  engine  were   similar   to   those   of   the   stock
gasoline-fueled    version.    Valve    timing    was    measured
 independently,  however, as  these  measurements were necessary as
a  point   of  reference  for  the   redesign  of  the  intake  side
camshaft.   These measurements are  given  in  Table  1.  Table  2  is
a summary of the intake valve  events in a stock (gasoline-fueled)
engine as well  as the measured events from the modified engine.

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                               -6-
                             FIGURE 2
                   CA180E ENGINE INTAKE CAMSHAFT
                    FUEL/AIR CAM LOBES INDICATED
                           FUEL LOBES
                             Table  1
         Stock Intake Valve Event Timing  Measured  By  EPA
Crankshaft Position
 7-1/2 degrees ATDC
    15 degrees ATDC
    24 degrees ATDC
    35 degrees ATDC
    59 degrees ATDC
   129 degrees ATDC
    17 degrees ABDC
    42 degrees ABDC
53-1/2 degrees ABDC
    65 degrees ABDC
91-1/2 degrees ABDC
        Valve Lift
.005 i nches
.020 inches
.050 inches
.100 inches
.200 i nches
.332 inches (maximum lift)
.200 inches
.100 inches
.050 i nches
.020 inches
.005 i nches

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                               -7-
      It  should be noted that a  valve  lift  of  .005  inch  was used
 to  denote  valve-open  and  valve-closed  events.   The  criteria
 Nissan  used  to define  opening  and closing  was not  available.
 There  is a substantial difference, evident  in  Table 2,  between
 the  valve timing  information provided by Nissan and  the  timing
 measured  by  EPA.    The definition  of  what   constitutes  valve
 opening  may  explain  some  of   this  difference.   Also,  Nissan
 milled the engine  head to  increase the compression ratio  on  the
 M100-modified  engine;  this modification  may  also  account  for
 much of  the  timing difference.

     The  production  of  the   intake   camshaft   to  accommodate
 2H2/CO  fueling  was   outsourced  to  General  Kinetics  Co.  Inc.,
 Detroit,  Ml.   A summary of the  camshaft  specifications  for  the
 redesigned  shaft  is given  in  Table 3.  Timing and design  for
 the  air  as  well  as  the   fuel  cams  was  altered.    Air   valve
 opening  commences  at  15   crankshaft   degrees  before  top dead
 center (BTDC),  and closes at 30 crankshaft  degrees after  bottom
 dead  center  (ABDC).   Opening of  the  fuel  valve commences  at 15
 degrees ABDC:   it  closes at approximately 65  BTDC,  for an open
 time  of  100 crankshaft  degrees.  The  height  of the fuel  valve
 lift  is  .0787  inch.   Valve head diameter for  both  air and  fuel
 valves are similar to  stock intake valve, 1.340  inch.

     The  intake  cam  lobes  on   the  stock  camshaft opened  the
 valves  through  a  hydraulic lifter  mechanism.    To  accommodate
 the acceleration change caused  by shortening  the  cam event to
 100 from 248 while maximizing  valve  lift,  it  was necessary to
 increase  the  diameter  of  the  base  circle  of  the  fuel cam.
 Lengthening  the base  circle  diameter  of  the  fuel  cam,   while
 maintaining  the  same lift,  mitigates wear caused by the contact
 of the sharply accelerating cam  on the lifter,  hence  increasing
 Ii fter durabiIi ty.

     The  stock  hydraulic   lifter  system,  however,  was  clearly
 unacceptable for the  increased base  circle  diameter  of the fuel
 lobes.   Had  the  stock  lifter  been   used,  contact  with  the
 lengthened cam base circle would have  kept  the  fuel  valves open
 continuously.   It  was  necessary,  then, to replace the hydraulic
 lifters with  mechanical lifters  that  could be  tailored to  the
 new base  circle  height.  A  lash of  .003  inch was also added to
 the new  mechanical  lifters to  improve wear.   The design  and
 construction  of  the  mechanical  lifters   was   done  by   Batten
 Engineering of Romulus, Ml.

     A 4-cyUnder  light-duty  automotive engine with   a   stock
 valve  configuration   similar   to   the  test   engine  has  been
modified  for  H2  fuel  operation  and   is   described  in   the
 I iterature.[12]   Though our  gaseous  fuel  was  of  a  different
 composition than the  pure  H2  fuel  in  reference  12,  this paper
was useful  because  it  described  a modified  fuel   system that
could potentially  be  adapted  for our application.    The  valve
 timing information was of   particular  interest   to us;  the fuel
valve timing specifications were used  as a  general  guide during
 the design of the gaseous fuel  intake system for our engine.

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                               -8-

                             Table 2

        Stock/Ml00-Modified  Intake Camshaft Specifications
    Specif icat ion

Cam height

Valve Lift

Valves open*
(crankshaft degrees)

Valves close*
        Standard
     CA18DE Engine
1.59391.5951  inches

     .335 inches

      15 BTDC


      53 ABOC
Measured By EPA
On M100-Modified
    Eng i ne	
   .332 inches

    7.5 ATDC


   91.5 ABDC
      Indicates not measured by EPA.
      Lift   =   0.005   inches  measured  by   EPA;   criteria  not
      available for standard engine.
                             Table 3

                 Intake Camshaft Specifications -
                    2H?/CO Fuel Modification
   Speci f icat ion
Valve lift

Valve head diameter

Valve opens*
(crankshaft degrees)

Valve closed*
(crankshaft degrees)

Total value event
   Air  Valve

   .3220  inches

   1.340  inches

   15  BTDC


   30  ABDC


   225
 FueI  VaIve

 .0787 inches

 1.340 inches

 15 ABDC


 65 BTDC


 100
     Valve Iift = 0.005 inch.

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                               -9-
      B.     Fuel  System  Modifications

      The  2H2/CO fuel  is  a  gaseous blend with  a composition  of
 66  and 34  volume  percent  H2  and  CO  respectively.   This  fuel
 is  stored  in  compressed  gas cylinders  ("T"  size)  at  1600-1800
 psi.   A fuel  supply  cylinder  is anchored  to a concrete  safety
 stop  outside of the  test  cell, approximately 10  feet from  the
 cell  wall  during  testing.   The bottle,  fitted with a  regulator
 and   pressure   gauge,   is  opened  by  a  hand   valve   prior   to
 testing.   The fuel  line  from  the bottle  is  1/4-inch  stainless
 steel  tubing,  22 feet in  length from bottle to cell wall.

      The  stainless steel  fuel  line  enters  the  cell  through  a
 hole   drilled  through    the   concrete   block  wall.    A  Gould
 electrically  controlled solenoid valve  is  located in  the  line
 immediately  after  the  wall.   An  electrical   signal   from   an
 accutator  in  the control  room  controls  the  opening  of  the valve
 to  accept  flow  from either  of two  lines.   The  first line  is
 connected  to  the fuel  supply  while  the second  extends from  an
 N2  gas  source  outside  the  cell.   This  N2  gas  is  used   to
 purge  the fuel  lines  in the  cell prior  to  and immediately after
 testing.   A  shut-off  valve  in the  purge  line,   when closed,
 keeps  N2  gas  out  of  the  cell   fuel   lines  following  the  purge
 operat ion.

     The  fuel  line from the cell wall  to a  fuel flow  regulator
 measures  approximately  54-1/2  feet.   This  regulator   is  a Twin
 Bay   Model   TB-100.    Gas   flow  through  this  regulator   is
 controlled  by a  flexible diaphragm.   The  diaphragm  is opened
 proportionally  to  the  pressure exerted  by  a  stream of  air
 provided by  a  tank of  compressed  air;  the pressure  exerted  by
 this  airstream  is  controlled  by  a  valve  located  in  the cell
 control room.
            fuel  flows  from  the  Twin   Bay   regulator  to  a
switching  valve.    This  valve  has  two  positions:    the  first
supplies fuel  to  the engine, while  the second diverts  the gas
stream  to  the  scrubber during purging of  the  test  cell  fuel
lines.   During testing,  the fuel  flows   from  the  valve  to  a
rotameter  calibrated  to  measure  0-10 SCFM.   The  fuel  passes
through  this gauge  and  then  through a  tee; a pressure gauge  in
the control room is operated by flow through this tee.

     The final  stage  of  the  fuel  system supplies  the gaseous
fuel  to  the  combustion chamber ports.   From the  tee mentioned
above, the  fuel  passes to a a cylindrical  plenum,  this plenum
serving as a header to four  flexible  fuel  lines.   Inserted  in
each  of  the  four fuel  lines approximately 17  inches from each
cylinder is  a  2-stage  H2  flame  arrestor.  The  fuel  lines  are
connected  to threaded  fittings which are  screwed  into the fuel
injection  ports  in  the  valve  control  assembly.   The  2H2/CO
fuel  is  supplied  to the  combustion  chambers by  the opening of
the fuel  valves.

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                               -10-
V.    Exhaust Analysis

      Engine  exhaust  passes  from  the exhaust  pipe  to  a 2-1/2
 inch  diameter   flexible  metal  tube.   This   tube   passes   the
exhaust  overhead  to  a  6-inch rigid   tube  hung  from  ceiling
supports.  The  rigid tube delivers  the  exhaust  to a  Philco Ford
350  cfm  constant  volume  sampler   (CVS).   Total   length  of   the
flexible and rigid tube sections is 40 feet.

      A  gaseous  sample   line   and  electronic  ties  have  been
extended  through the  cell  ceiling  and connect  the mechanical
CVS with  an  electronic display panel in the  cell  control room.
A  fitting in  the  sample line  at  the control  room enables  bag
sampling   at   this   point.    Analysis   of   bag   samples    is
accomplished  at a  bank  of analyzers  located  in  another test
cell.  Emissions measured as  hydrocarbons  (HC) are measured  on
Beckman  model  400  flame  ionization detector  (FID).   NOx level
determination    is   conducted   on   a   Beckman   model    951
chemiluminescent NO/NOx analyzer.    CO   is  measured by  infrared
technique using  a Horiba model A1A23  infrared analyzer.

      Exhaust  formaldehyde  was  measured  using a  dinitrophenyI
hydrazine  (DNPH)  technique.[13]    Exhaust  carbonyls  including
formaldehyde are reacted with  DNPH solution  forming hydrazine
derivatives;   these  derivatives  are  separated  from  the  DNPH
solution  by  means  of  high  performance  liquid  chromatography
(HPLC), and  quantization is  accomplished  by  spectrophotometric
analysis of the  LC effluent stream.

     A  second  sample  line  extends  from the  CVS  to  a  heated
manifold.    This  manifold   contains  ports   for   three  DNPH
sampling   cartridges.    Flow   to    individual   cartridges    is
controlled by  three  solenoid  valves located downstream from  the
DNPH  cartridges.  The  hot sample  gas flows through  a cartridge
and then to a heat  exchanger where the gas  is cooled  to 21C.

     Flow for  the formaldehyde  sampling system is measured with
a Porter  Mass  Flow Controller  calibrated   to 5 standard liters
per minute.  Gaseous  sample from the heat  exchanger flows past
a solenoid valve and is pumped  through  a dual  filtration system
to remove any  water  present in the sample.   The pump is a Gast
model  746A  with a  maximum  rated   pressure of 100  psig.   The
exhaust sample  is  then passed  through  the  mass flowmeter where
sample  flowrate  is  determined;  an  electronic  gauge   in  the
control   room  is  wired  to  the  flowmeter and  displays  both
flowrate  and  total  accumulated   volumetric   flow  through  a
selected DNPH cartridge.

-------
                               -11-
VI.   Results  From  Testing

      Several  attempts were made  to  characterize  the  emissions
profile  of the  test  engine when  it  was operated on M100  fuel.
These test   results   are   compared   below   to  emission   levels
measured  when  the engine  is  fueled with  2H2/CO  to quantify
any change  in emission levels due  to  the different  fuels.

      Nissan  requested that the  engine  not  be  operated at wide
open   throttle   conditions  due  to  poor   intake  mixing.   We
therefore  measured  emissions  over  speed  and   load  conditions
that  do  not  excessively  burden  the  engine:    idle  (no  load),
1600  rpm/30.8 ft-lb and 2400 rpm/40.5  ft-lb.

      Air/fuel  ratio  (A/F)  and   injection  timing may  be varied
through  the  use of a  rheostaticaIly equipped control panel that
Nissan provided with  the  engine.   A/F  ratio was  measured with
an NTK Micro  Oxivision MO-1000 A/F ratio meter.  This  meter was
used  as  a guide  to  control  engine A/F ratio;   A/F  ratio was
controlled  to  near  stoichiometric conditions  for  testing with
Iiquid fuel.

      Following   the   conversion  of   the   intake   system  for
operation  with  gaseous  fuel   the  engine   was  again  emission
tested over  several   modes  with  2H2/CO  bottled  gas  fuel.   The
results  from  this   preliminary  testing  on  both   liquid  and
gaseous fuels are presented in tabular form  below.

      Though  test  results from operation on both fuels by mode
are  presented  in  the  same table  for  comparison,  significant
differences   in  test   conditions   occurred.   These  differences
unfortunately make only  general  comparison  of test results from
these fuels possible.

     We  initially  set  up  the engine in  the  liquid  fuel  mode
with  a catalytic  converter  in  the  exhaust stream.   Emission
results  from  M100  testing were  of  course  affected  by  the
placement  of  this converter  in  the  exhaust stream.    Emissions
from  testing  on  the  gaseous  fuel  were  not   influenced  by  a
catalytic  converter;   these  are  engine-out  emissions.   Future
efforts will  include  additional   testing  which  will   enable  a
better comparison  of  engine-out emissions with  both  fuels.  It
is also possible  to  run the test engine for only  a  short  time
on the bottled  gas  fuel.   Safety factors prohibit filling a gas
T-cylinder  with the  2H2/CO mixture   to more  than 1800  psig.
This  is  enough  fuel   to  allow  for a  brief  warmup  and  5  minute
emission test at 2000 rpm/27  ft x  Ibs of torque,  for  example.
Consequently,  warmed  steady-state conditions  were not reached
prior to  emissions testing on  the bottled  gas  fuel.   Adequate
fuel   storage  for emissions  testing is therefore another problem
to be addressed in our future efforts.

-------
                               -12-
     Table  4 presents  the  results  from emission  testing with
both  fuels  at no load  idle  conditions.   It  was not possible  to
warm  the  engine to  steady-state  conditions  prior  to  testing
with  the gaseous  2H2/CO  fuel,  however.  Gaseous  fuel  testing
consisted  of a  cold start,  adjusting  engine  speed  by  varying
the  A/F  mix until  the  desired speed  was  attained   and  then
sampling  exhaust  emissions  over a  5-minute  period.    Exhaust
emissions sampling with M100 fuel was  conducted over a 5-minute
period  with  the  test  engine warmed  to  steady-state conditions
(coolant and  oil temperature monitored).

     The engine  idled  at  750  rpm with  M100  fuel  under  control
of  the  electronic  control unit; the engine was  idled at  various
speeds  with gaseous 2H2/CO  fuel.   The  engine appeared  to run
much  smoother on the gaseous  fuel;  it  did  not appear to  labor
perceptibly at 575 rpm.

     A/F  ratio  with M100 fuel   operation was measured  with   an
NTK  MO-1000  meter.   The warm  engine  was  controlled  to  near
stoichiometric conditions using the A/F control  box.   The A/F
ratio  meter  proved  unsuitable  for the gaseous  fuel  mixture,
however.   A  maximum  value  for  lambda   (A/F  actual   over  A/F
stoichiometr ic)  of  2.29  can be  displayed  by  the  meter.  This
equates  to  an  A/F  ratio  of   14.7   (6.4   is  approximately  a
stoichiometric  condition for  M100).[14]   The sensor  to  the
meter was calibrated as if methane I  fuel  was  being  used,  as the
carbon/hydrogen  and  oxygen/carbon  ratios are  similar  for M100
and  the 2H2/CO  mixture.   The  meter   indicated  a   lambda value
of  2.29 at  625  rpm;  adjustments to the fuel and  air  to raise
the  engine   speed  cause  the  meter  to  tilt,  indicating   an
out-of-bounds  (excessively  lean for  the meter) condition had
been reached.

     Air  and  fuel  were   measured directly  into  the  engine   in
order to calculate A/F  ratio for the gaseous fuei  at idle.  Air
was measured  with  a hot  wire  anemometer through  a  calibrated
orifice, while  gaseous  fuel was measured with  a  rotameter.  An
example of the calculation of A/F from this  data  is included   in
Appendix B.

     A/F  ratio  with  the  gaseous   fuel  was  very  lean  when
compared to liquid fuel  operation.  A/F  ratio with  gaseous fuel
was  calculated  at   14.8   for   625   rpm  and  no  load  idle
conditions.    The  mixture  became    leaner   as  engine   speed
increased.   Between 1200  and 1500 an  A/F ratio of  approximately
26.0  was  measured.   An  A/F   ratio   of  26  equates   to  an
equivalence  ratio  of  approximately   0.25;  Hama,   et   al.  [12]
obtained A/F  ratios  as low  as  0.20 when operating on pure  H2
fuel.   A graph of A/F  ratio versus  engine speed at  no-load idle
conditions for 2H2/CO fuel is given  in  Figure 3.

-------
-13-
Table 4
Emission Testing, Nissan CA18DE Engine
M-100, 2H2/CO Fuels, Cold Idle Mode
Fuel
M100*
2H2/CO
2H2/CO
2H2/CO
2H2/CO
2H2/CO
2H2/CO
2H2/CO
2H2/CO
2H2/CO
2H2/CO
Eng i ne
Speed
(rpm)
750
575
625
625
900
1000
1000
1200
1250
1500
1500
Air/
Fuel
(ratio)
6.88
N/A
N/A
14.8
N/A
20.2
24.3
26.0
26.5
26.0
26.0
HC CO
(q/hr) (q/hr)
0.38
0.01 61.96
98 . 24
47 . 03
0.02 66.36
0.28 166.01
247 . 38
346.15
261 . 64
0.14 439.32
309 . 06
C02
(q/hr)
1826
928
1541
1475
1696
2062
1945
2326
2545
3016
3127
NOx HCHO
(q/hr) (mq/hr)
0 . 05 11.9
21.5
21.1
28.3
18.2
0.55 27.6
0.06 35.1
0.12 15.1
0.11 18.4
0.12 22.9
0.11 18.8
     Engine   warmed   to   steady-state  conditions;
     converter in place in the exhaust stream.
N/A  Not avai(able.
     None detected.
catalyt ic

-------
                              -14-
                              FIGURE 3
                       A/F VERSUS ENGINE SPEED
                       NO LOAD IDLE CONDITIONS
             30
             25
             20
             15
             10
               A/F RATIO
                 700      900      1100     1300      1500

                         ENGINE SPEED (RPM)


                 2H2/CO FUEL   + M100 METHANOL FUEL
     Emissions  measured  as  hydrocarbons  (HC)  with  a  propane
calibrated FID were  0.38 grams per hour  with the engine  fueled
with M100.   Engine-out  HC emissions were  essentially  negligible
with   gaseous   2H2/CO;    two    tests    indicated   more   than
insignificant amounts  of HC,  however.  The  gaseous  fuel  results
are  engine-out   emissions,  however,  while  the  M100  data  was
influenced  by the  presence  of  a catalytic  converter   in  the
exhaust  system.   Additional  testing  will have  to  be  conducted
to confirm or deny these  levels.

     CO  emissions are   also  presented  in  units  of  grams  per
hour.   The  catalyst-equipped  M100-fueled  engine  produced  no
measureable  amounts   of  CO;  this  was the  result  of a  single
test,  however.   Additional testing  under engine-out  conditions
will have  to be  conducted in  order  to provide sufficient  data
for  comparison.    CO  emissions   from  gaseous   fuel   operation
increased  as  engine  speed  increased.   It  is  interesting  to
note,  however,  that   in  the case  of  the  gaseous  fuel,   this  CO
might  be better  described as "unburned fuel"  rather than viewed
as a product of partial  combustion.

-------
                               -15-
      It  was more  difficult to  identify  a relationship  between
 engine  speed and  emissions  levels of NOx  and HCHO at  no  load
 idle   conditions   with  gaseous   fuel.    NOx   emissions   are
 identified  with  higher temperature engine  operation;  as  engine
 oil   and  coolant   temperature  were  not   stabilized  prior   to
 emissions   testing,  combustion  chamber  temperatures  may have
 varied  during  each emissions test.  One  test  at 1000  rpm engine
 speed gave  a value of 0.55  grams  per hour for NOx, much  higher
 than  previous   or  successive  tests.   HCHO  emissions   do   not
 appear  to  correlate   well  with  engine  speed  and hence fuel
 consumption.   One  control  test of  a DNPH  cartridge, however,
 indicated  contamination or  a  chromatograph  inconsistency that
 would  have  allowed  an error  of   10  milligrams  per hour to  be
 added to  HCHO  actually measured.   Several more  tests  will have
 to be conducted  to  determine the magnitude of  this  error.

     Table  5  presents the  results  of  several  emission tests
 conducted with the  engine operating under  load.   The  tests with
 M100  fuel  were  conducted with  the engine  operating  at   warmed,
 steady-state  conditions and with  a  catalyst  in  the   exhaust
 stream.   The gaseous  fuel  tests  measured engine-out  emissions.
 The  engine  was  not  run at speeds  higher  than  2000   rpm   on
 gaseous fuel.

     The  first tests  with  M100 fuel were conducted at an  engine
 speed of  1600  rpm  and a brake torque  of 30-31  ft x  Ibs (9.4
 -9.6 brake  horsepower).   Emissions results were  inconclusive  as
 they varied  considerably.   Brake  specific HC  varied  from 0.002
 to  11.81   grams   per   brake  horsepower  hour  (g/BHP-hr);  brake
 specific  NOx varied from 8.89  to  0.86  g/BHP-hr.   These tests
 will  be repeated  after the  engine  is  reconfigured   to  run   on
 liquid  fuel again;  catalyst  light-off   and   the   problem with
 air/fuel mixing  with   liquid  fuel  that  Nissan made us aware  of
 may have  contributed  to this variability.  Testing at 2400  rpm
 was  also   inconclusive,  due  greatly  to  the   limited  number   of
 tests  conducted.   C02  emissions  varied  from   472  to  634
 g/BHP-hr over these two tests, a very substantial difference.

     Testing with  gaseous  fuel  was  conducted  at  2  different
engine  speeds:   1500  and 2000  rpm.   At  1500  rpm  the throttle
was opened  to 4.5  in.  HG manifold vacuum.  Fuel  was adjusted  to
bring A/F  ratio  to   16.07  and  11.9  at  1500  and  2000   rpm
 respectively.  A  load  of 24.1  ft  x Ibs was placed on  the  engine
at 1500 rpm;  26.6  ft  x Ibs was  placed  on  the  engine  at 2000
 rpm.   Manifold  vacuum at 2000 rpm was 7.0 in. HG.

     The engine  ran very smoothly  under  load with the  gaseous
 fuel.   The lower  manifold vacuum  figures,  however,  suggest that
 the  throttle was  substantially  open,  indicating  that   further
 increases  in power  may be difficult  to  obtain  at  these engine
speeds with the engine as presently configured.

-------
                                         -16-
                                        Table 5

                        Emission Testing, Nissan CA18DE Engine
                           M100, 2HZ/CO Fuels, Load Testing
       Engine          Air/  Brake  	Brake Specific Emissions
Fuel
M100*
M100*
2H2/CO
M100*
M100*
2H2/CO
Speed
( rpm) i
1600
1600
1500
2400
2400
2000
Torque
(ft Ib)
30.8
30.4
24.1
40.5
40.8
26.6
Fuel
( ratio)
6.60
7.00
16.07
6.34
6.38
11.9
HP BSHC BSCO
(BHP) (g/BHPhr) (q/BHPhr)
9.
9.
7.
18.
18.
10.
62
39
01
97
90
32
.002
11.81
0.20

0.07
0.13
0.46

1.91
0.35
1.45
2.27
BSCO 2
(g/BHPhr)
781.
762.
717.
472.
634.
426.
BSNOx
(g/BHPhr)
8
0
2
0
0
8
.89
.86
.84
.20
.01
.57
BSHCHO
(mg/BHPhr)
1.5
1.2
4.7


2.0
*    Engine warmed  to  steady-state conditions;  catalytic  converter  in  place  in  the
     exhaust stream.

     None detected.

-------
                              -17-
     The  emissions   results   from   gaseous  fuel  testing   are
 inconclusive  due to  the  limited  number of  tests performed at
 the  time  of  this  report.   NOx,  however,  was measured  at  8.57
 g/BHP-hr  at  2000 rpm engine speed,  a higher  level  than had  been
 recorded  during liquid  fuel  testing  at greater  speed and  load
 conditions.    Again,    liquid   fuel    emission    results    were
 influenced  by the presence  of a  catalytic converter.   CO, at
 2.27 g/BHP-hr,  2000  rpm conditions might be considered somewhat
 low when  compared with  the warmed,  catalytic converter equipped
 liquid  fuel   emission  results.   More  carefully   controlled
 emission   tests  will   be  performed   in  order   to  properly
 characterize   the   emissions  profile   from   the  engine   when
 operated  on both the  liquid and gaseous  fuels.

 VII. Project Highlights  To Date

     1.    The  engine  ran  very smoothly at idle  and  under  load
 conditions  with   the   simulated   dissociated  methanol   2H2/CO
 fuel.   Visible  engine vibration during gaseous  fuel operation
 was  noticeably  reduced  from the  level  experienced  with   the
 engine operating on  liquid methanol  fuel.

     2.    The  engine was able  to operate  over  a  very  wide
 range  of  A/F   ratio  setpoints with  the  2H;/CO  gaseous  fuel.
 A/F ratio was  calculated between  14.8 and 26.5  at  no-load  idle
 conditions between 625  and 1500  rpm.   At conditions  of 2000 rpm
 engine speed, 10.32 BMP, A/F ratio dropped to 11.9.

     3.    A direct  comparison of  emissions  test  results  from
 the engine  when it  is  alternately  fueled with  M100 and  2H2/CO
 is not  available at  this  time.    The  testing  with  M100  fuel
 utilized  a  catalytic  converter  in  the  exhaust  stream  while
2H2/CO  fuel  results  are  engine-out  emissions.    The   2H2/CO
 fuel   emissions  test  results may  vary  substantially  between
 tests  because  the  limited amount   of   2H2/CO  fuel   in  the   "T"
cylinder  storage bottles did  not  permit starting and warming to
steady-state conditions prior to testing.

-------
                               -18-


 VI11.Future  Effort

      This  engine  conversion  project  was  begun  to  develop  an
 engine   that  could  be  used  as  a  suitable   test   bed   for   a
 practical,   onboard   methanol   dissociation  system.    Further
 development   of   this   engine  concept  will  be   structured   to
 accommodate  this goal.   Immediate  plans  concern  development  of
 two measures  of  engine performance:

      1.    Emissions/fuel economy; and

      2.    Engine performance  at  lean operating conditions.

      Further  emissions  testing  at  various engine  speed/load
 operating  conditions  will  be  conducted  to   characterize  the
 emissions profile of this engine  when operated  on both M100 and
 dissociated  methanol.   A/F  ratio at these  various  test  points
 will  also be  determined.

      Previous  testing  with M100  liquid methanol  was conducted
 with  a  catalytic   converter   in  the  exhaust   stream.   This
 catalytic  converter   will  be  removed  in  order  to   provide
 engine-out emissions data for  comparison.

      The   effect  of   changes   in  spark  timing   on    engine
 performance  and  emissions in  the testing reported on  here was
 not measured.   Spark  timing will be adjusted  in  future  testing
 in order to  obtain  mean for best torque  (MBT)  conditions for  a
 range of engine  speeds.

     One way  to determine  the  proximity  to  the  lean   misfire
 limit at various  engine-operating  conditions  is  to obtain   a
 quantifiable  measure  of  increasing engine roughness   as  the
 air/fuel mixture  is  leaned out.  A measure  of proximity   to lean
 misfire  limit  may be  obtained directly,  through measurement  of
 changes  in cylinder  pressure during  the combustion effort.    An
 indirect   method   might   involve   the   measurement  of  the
 variability  in  successive   crank rotation  times  as  leanness
 increases.    The  test  engine   is not  equipped   with  a knock
 sensor;   it   should   therefore   be   possible    to   obtain    a
 quantifiable  measure  of engine performance  as  the lean   misfire
 limit is approached  when  the engine  is  fueled with the   gaseous
 2H2/CO blend.

     Kistler  Instrument  Corporation has  modified a  spark plug
 from this engine to accept a pressure transducer  adaptor.  This
 adapter, when  fitted  with a  Kistler  Model   601B1  pressure
 transducer  will  allow  measurement of cylinder  pressure   in  the
 otherwise  unmodified   engine.    Future  work    will    include
measuring  cylinder  pressure  changes  and  relating  them   to
 changes  in  A/F ratio as the lean  limit  is approached.

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                               -19-
 IX.   Acknow Iedgment s

      The  CA18DE   test   engine   described   in   this   report   was
 modified  for  use  with  M100 neat methanol  and loaned to EPA by
 the   Nissan  Motor  Corporation  as   part  of   an   ongoing   joint
 cooperative   effort  to   investigate   the   potential  of   neat
 methanol  as  an  alternative  motor   vehicle  fuel.   The authors
 also  appreciate  the  efforts  of  Jennifer  Criss and Marilyn  Alff
 of  the Control  Technology and  Applications  Branch,  ECTD,  for
 typing, formating,  and  editing this  report.

 X.    References

      1.    The  Clean  Air  Act  As   Amended  Through  July   1981,
 Section 211(c)(1).

      2.    Speech  by Charles L.  Gray,  Jr.,  EPA, OAR,  QMS,  to
 1983  Midyear  Refining Meeting of  the API, May  11,  1983.

      3.    Policy  Statement  by   Vice  President  of  the U.S.A.,
 George Bush,  March 6, 1987.

      4.    "Basic   Theoretical    Investigations   of   Decomposed
 Methanol,"  Bechtold,   Richard   L.,   Mueller   Associates,   Inc.,
 Department of Energy CONF-8306135, October,  1983.

      5.    "Resistively  Heated  Methanol  Dissociator  for  Engine
 Cold   Start   Assist   -   Interim   Report,"   Piotrowski,    G.,
 EPA/AA/CTAB/88-02, March 1988.

      6.    Proceedings  of  The Third  International  Symposium On
 Alcohol Fuels Technology,   Inagaki,   T. , T.  Hirota,  and Z.  Veno,
 Asilomar,  CA,  May 29-31, 1979.

      7.    "Dissociated  Methanol Engine  Testing  Results  Using
 Hz/CO  Mixtures,"  Proceedings of the  Eighteenth  Intersociety
 Energy Conversion  Engineering Conference,  Anthonissen, E.   and
 J. S. Wallace, Orlando, FL, August 21-26,  1983.

     8.    "Research  and Development of  Alcohol  Fuel  Usage  in
 Spark-Ignited Engines,"  Pefley,  R. K.  and L.  H.  Browning,  U.S.
 DOE DE-FG03-84CE50036, April,  1986.

     9.    "Dissociated  Methanol Test  Results," Presented  at
 the  Automotive  Technology  Development  Contractor  Coordination
 Meeting,   Finegold,   J.  G., and  J.   T.  McKinnon,  Dearborn,  Ml,
April, 1982.

     10.    "Design   and  Testing  Of  A  Dissociated  Methanol
Vehicle,"   Karpuk,   M.  E.   et   a I.,   Solar   Energy  Research
 Institute, Golden,  CO, October,  1988.

     11.    U.S.  EPA Contract No.  68-03-3540.

-------
                              -20-
     12.   "Hydrogen-Powered  Vehicle  With Metal  Hydride Storage
and  D.I.S.  Engine  System,"  SAE  Paper  880036,  Hama,  J.,  Y.
Uchiyama and Y. Kawaguchi, March 1988.

     13.   "Formaldehyde   Measurement   In  Vehicle   Exhaust  At
MVEL," Memorandum, Gil key, R. L., OAR,  QMS,  EOD,  Ann Arbor, Ml,
1981.

     14.   "Alternate    Fuels    Research    Guidebook,    Fuel
Characterization, Engine  and Vehicle  Testing,"  DOE/CE/50046-1,
December 1985.

     15.   "Internal  Combustion  Engines  and  Air   Pollution,"
Obert, E. F., Harper and Row, New York, NY, 1973.

     16.   Introduct ion t^> ChemicaI  Engineering  Thermodynamics,
3rd  Edition,  Smith,  J. M.  and  H.  C.  VanNess,  McGraw-Hill, New
York, NY, 1975.

-------
                           APPENDIX A
        TEST ENGINE SPECIFICATIONS - M100 FUEL OPERATION
Manufacturer
Basic engine designator
Displacement
Cylinder arrangement
VaI vet rain
Combustion chamber
Bore x stroke
Compression ratio
Compression pressure
Fuel control system

EGR
Valve clearance
Idle speed
Engine oiI

Fuel
Air/fuel  control

Spark advance control
Nissan Motor Co.,  LTD.
CA18DE
1809 cc
4-cyIi nder,  i n-1i ne
DuaI-ove rhead camshaf t
Pent roof design
83 mm x 83.6 mm
11.0
16.5 kg/square cm  (350  rpm, 80C)
Electronically controlled  fuel
  inject ion
EGR not used
0 mm (automatically adjusting)
750 rpm
Special formulation supplied by
Nissan for methanol engine
operat ion
M100 neat methanol
Excess air ratio may be varied
from 0.5 to 2.0 by means of an
external  control
Ignition timing can be varied from
0 BTDC to 54 BTDC by means of an
external  control

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                        APPENDIX B

       AIR/FUEL RATIO CALCULATION WITH 2H2/CO Fuel


 Air/fuel  ratio is  defined  [15]  as:

       Mass flowrate  of  air   , dimension I ess             (1)
       Mass flowrate  of  fuel


 Molecular weight of  air, 28.89,  approximately.

 Calculate molecular  weight  of fuel,  2H2/CO:

       2/3 (molecular weight  of  H2, 2)      =    1.333
       1/3 (molecular weight  of  CO, 28)     =    9.333

       Molecular weight  of fuel,  approximately 10.666


 At  standard  conditions, for  gases,

 PV  =  nRT                                                 (2)

 Where:

 P,  pressure, atmosphere
 V,  volume, cubic feet
 n,  Ib. moles
 R,  constant, .7302 atm  ftVlbmol  R  [16]
 T,  temperature, R


 At  standard conditions,

 T = 492 R

 P = 1  atm

 Mass  flowrate may be defined as:

 PVT (molecular weight) = nT(molecular weight)            (3)
 RT

Where:

VT,  Volume/time,  ftVminute

 nT,  Ib moles/minute

Given,

Air flowrate, 6.0 standard  cubic feet/minute (SCFM)

-------
                  APPENDIX B (CONT'D)

      AIR/FUEL RATIO CALCULATION WITH 2H2/CO Fuel


Fuel flowrate, 1.1 SCFM

Calculate A/F ratio:

Mass flowrate of air, from (3)

(latm)(6.0 SCFM)(28.89 Ib./lbmol) =  .4825  Ib./minute, air
       (.7302) (492R)


Mass flowrate of fuel,

(latm)(1.1 SCFM)(10.666 Ib./lbmol) = .0327  Ib./minute, fuel
       (.7302)(492R)

From (1),

A/F = .4825 Ib/minute = 14.8,  answer
      .0327 Ib/minute

-------