EPA/AA/TDG/93-04
                         Technical Report
              Conversion of Methanol-Fueled 16-Valve,
            4-Cylinder Engine To Operation On Gaseous
                    2H2/CO  Fuel - Final Report
                                by
                        Ronald M.  Schaefer
                         Fakhri  J.  Hamady
                         James C. Martin
                            March  1993
                              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 o£ 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
           Regulatory Programs and Technology Division
                   Technology  Development  Group
                        2565 Plymouth  Road
                       Ann Arbor, MI   48105

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       UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

                    ANN ARBOR. MICHIGAN 48105
                           MAY  -|
                                                        OFFICE OF
                                                     AIR AND RADIATION
MEMORANDUM


SUBJECT:  Exemption From Peer and Administrative Review


FROM:     Karl H. Hellman, Chief
          Technology Development Group


TO:       Charles L. Gray, Jr., Director?"
          Regulatory Programs and Technology Division


     The attached report  entitled  "Conversion of Methanol-Fueled
16-Valve, 4-Cylinder Engine To Operation On Gaseous 2H2/CO Fuel  -
Final  Report,"   (EPA/AA/TDG/93-04)   describes  the  last  phase of
testing 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  was
operated  on both  M100  and  simulated  dissociated  methanol  (67
percent  hydrogen and  33  percent carbon  monoxide)   fuels.    This
report describes recent modifications made to the engine and fuel
delivery system and summarizes the results from recent testing on
both fuels.

     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:    ?"~1 V^- 1L3
Charles L. Gray,/JfrC, Director, RPT
               / /

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                        Table of Contents
                                                            Pag*
                                                           Number


I.   Summary	1

II.  Introduction	2

III. Description of Test Engine and Fuel System Modifications. 3

IV.  Exhaust Measurement Procedure 	 .   . 5

V.   Discussion of Test Results	6

VI.  Future Efforts	14

VII. Acknowledgments	14

VIII. References	14

APPENDIX A - Test Engine Specifications	A-l

APPENDIX B - M100 Test Results	B-l

APPENDIX C - 2H2/CO Test Results	C-l

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 I.

     A  16-valve,  4-cylinder light-duty automotive engine  has  been
 converted  to operation on a mixture  of  hydrogen (Hj) and  carbon
 monoxide (CO) gaseous fuel in a 2:1 molar ratio of Hj and CO.  This
 engine  has been  used  to  investigate the  difference in  emission
 levels  and power output between two  different  fuels:  M100  neat
 methanol and simulated dissociated methanol gaseous fuel  (2H2/CO).

     Previously, several engine/fuel system modifications were made
 in  an attempt  to increase power output when the gaseous  fuel was
 used [1].   Several  intake port/fuel system configurations as  well
 as   fuel   injection  nozzle  designs  were   evaluated.    These
 modifications  were evaluated  to determine  the effects  of  fuel
 pressure,  injection location, and fuel delivery methods on  engine
 performance.   When  using  2H2/CO fuel,  the largest torque  achieved
 at   2,000  rpm,  WOT operating  conditions  was  80  ft-lb.    This
 represents about 80 percent of  the maximum torque levels  obtained
 with M100  fuel  at the same WOT, 2,000 rpm operating conditions.

     This  torque level was considered satisfactory for gaseous  fuel
 operation.   It was then necessary to monitor engine performance
 (output torque,  combustion  efficiency, and emissions) at several
 different  operating conditions.   This report  summarizes  engine
 performance when operating on both M100 and 2H2/CO fuels  at several
 different  operating conditions.   The main  goals of this final
 testing were  to demonstrate that there  were  certain operating
 conditions where the engine produced more/similar torque, less CO
 emissions,  and had a better combustion efficiency when operating on
 2H2/CO fuel.

     When  the  2H2/CO fuel  was used, two different intake camshafts
.were used.  The stock camshaft had the same cam profile  for  both
 the air and fuel valves  and  was also used  with M100 operation.
 This camshaft was  used when  the  torque value  of 80  ft-lb  was
 achieved with  the gaseous fuel.  The modified camshaft had  a  very
 short and  fast valve lift  for the fuel valve and the  same air valve
 event as the stock camshaft.  The maximum torque achieved with  this
 camshaft during this testing was 43 ft-lb.   Tests were conducted at
 both 2,000 and 1,500 rpm.

     When  the  stock intake camshaft was utilized with 2H2/CO fuel,
 torque  values were very similar to levels obtained with M100 fuel,
 even higher at low  loads  (only  varying by 20 percent  at WOT) .  At
 high loads with the modified  camshaft,  torque values  began  to
 decrease from  M100 levels more rapidly,  perhaps  due to  the  very
 short  fuel valve event.   However,  there  were  several operating
 conditions when using 2H2/CO fuel that resulted in higher  torque
 values  than were achieved with  M100 fuel.

     The next  goal was to operate the engine on 2H2/CO  fuel and
 achieve similar  CO emission levels as  when  fueled with M100.  With
 the stock camshaft  during  medium-load   operation,  the  engine

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                               -2-
produced somewhat  similar levels of CO when  operating on either
fuel.  (2H2/CO fuel operation produced  about  30  percent higher CO
emissions.)  However, when  the modified camshaft was used during
medium-load operation, both fuels produced almost equal amounts of
CO emissions.

     The  last  goal   of  this  program  was  to   match  combustion
efficiencies when  using  either fuel.   During low to medium-load
operation, combustion efficiency values for  each  fuel were very
similar at 2,000 rpm.   At higher loads, however,  efficiency values
with the gaseous fuel begin to taper off from M100 levels.

     This test program did meet the goals originally set for this
engine conversion  program.   First,  the engine  was successfully
converted  to operation  on  simulated dissociated  methanol  fuel.
Also,  after  much engine  and  fuel system  optimization  work,  the
engine did perform  comparably to M100 operation when the 2Hj/CO fuel
was  used.   Similar torque  values,  CO  emissions,  and  combustion
efficiencies were  noted  during low to  medium-load operation for
both fuels.

II.  Introduction

     With  recent  advances  in  internal  combustion engines  and
emission control development, new technologies are being directed
toward improving combustion efficiency, multi-fuel capability, and
reduced emissions.   Recent developments in engine technology have
enhanced stable burn and  reduced emission  levels.   The use  of
various alternative fuels is also being addressed to satisfy clean
air legislation for the 1990's.

     One alternative fuel candidate is the concept of using exhaust
waste heat to provide the energy necessary  for the dissociation of
methanol (CH3OH)  to hydrogen and  carbon monoxide.  Methanol may be
catalytically  decomposed to  H2  and CO gases  according to  the
reaction:
     CH3OH(0	2H2(W + COfc,


     The decomposition of methanol to this gaseous fuel mixture has
been postulated as a more efficient method of using methanol as a
light-duty motor vehicle fuel.   The major attraction of methanol
decomposition  is  that  the  resulting gases have  a  higher heating
value per pound than the original liquid methanol. A discussion of
the application of dissociated methanol  as a light-duty automotive
fuel was presented in previous reports.[2,3]

     In  order  to  evaluate  this concept,  EPA modified  a  Nissan
CA18DE  multi-valve  engine  to  better  utilize  the  combustion
characteristics of dissociated methanol fuel.   This  engine was a
stock model modified  by Nissan Motor  Corporation for  use with

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                               -3-
liquid methanol.  The engine was loaned to EPA by Nissan for use in
alternative fuels research.  This report summarizes the most recent
EPA efforts  in the investigation of  dissociated methanol  as an
automotive fuel for this engine.

     The simulated dissociated methanol product gas  used in this
work was a mixture of  H2 and CO gases  in the  molar ratio 2H2/CO.
EPA did  not possess  a methanol dissociation  system capable of
generating the necessary quantities  of gaseous fuel at  the time
work on this project was started; the engine was therefore tested
on a bottled gas mixture of 2H2/CO.

III. Description of Test Engine and  Fuel  system Modifications

     Several modifications were made to this engine  by  EPA since
its delivery  from  Nissan; these modifications were detailed in
previous EPA technical  reports.[1,2,4]  This section will describe
the test engine  and previous modifications made  for  operation on
2H2/CO  fuel.  This was the state of the test engine at the beginning
of the work described in this report.

     The engine used for this project  was a Nissan  CA18DE engine
with  an  in-line,  4-cylinder,  1.8-liter capacity.    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 dual overhead camshafts.

     The test  engine was  initially  modified by Nissan  to better
utilize the qualities of M100 neat methanol over unleaded gasoline.
These  modifications  were  discussed   in  detail  in  an  earlier
report.[5] A summary of the test engine specifications when fueled
with M100 neat methanol is included  in this  report in Appendix A.

     EPA  then  modified  this  engine  for  use  with  simulated
dissociated  methanol  fuel  (67  volume percent  Hj  and 33  volume
percent CO) .   The first was the  installation, at Nissan's request,
of a thicker  head gasket.  This thicker  gasket raised the clearance
between the valve face  and the piston crown;  this modification was
made to improve the durability of the engine.  This thicker gasket
lowered the compression ratio from 11.0 to 10.5.

     With M10O fuel, the  engine utilized a 4-valve  per cylinder
valvetrain configuration  (two  intake  and two exhaust valves per
cylinder).  When operating on the gaseous fuel,  this arrangement
was modified to allow for admission of air to the cylinder through
one intake valve only;  the  second intake valve supplied the  2H2/CO
fuel.  The exhaust side valve scheme was  not altered (Figure 1) .
This configuration  was used  for all  testing  described  in this
report with the 2HJ/CO  fuel.

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                                -4-
                             Figure 1

               Simulated Direct Injection Operation
                 Valve Scheme For 2H,/CO Fuel Use
     This valve scheme allowed  for  the admission of gaseous fuel
through only  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 MIOO-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-cylinder charge motion on the liquid-fueled
engine.

     When the  engine  was converted  by EPA to operation  on  2H2/CO
fuel, the control valve  slide and  actuator were disassembled and
the swirl control valves removed.   The runners  through the valve
assembly that contained holes for fuel injectors were welded shut
approximately^ 1/2-inch  upstream from  the  holes.   These  seals
prevented 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.

     With 2H2/CO fuel operation,  two different intake camshafts were
utilized.  The first was the stock M100 camshaft with similar air
and fuel valve events.  The valve lift here was 0.335 inches with
a  total valve  event of  225°.   The  modified  camshaft utilized
different valve events for both  air and fuel.   The air valve scheme
remained the  same  as the stock  camshaft.  The  lobes  on the fuel

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                               -5-


valves were altered to a  total  lift of 0.200 inches  and a total
valve event of 100°.  The development of this modified camshaft was
discussed in a previous report.[5]

     Fuel injectors were not used to deliver the 2H2/CO 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 holes  were  then  threaded to adapt to  the
fittings.

     A fuel supply cylinder outside  the test cell was used with 22
feet of 1/4-inch stainless steel tubing leading from the pressure
regulator on the  cylinder to  the  solenoid valve  inside  the test
cell.  The fuel leading from the  solenoid valve to a flame arrester
was  3/8-inch  in  diameter  and measured  approximately 27  feet in
length.  There were only  slight bends and no turns  in  this fuel
line so that few pressure  drops  in  the fuel delivery system would
occur.

     Before the  flame  arrestor  in  the fuel  line was a  pressure
gauge that would measure fuel pressure  to the intake manifold.  Ten
feet downstream of the pressure gauge was  another solenoid valve
followed by  a 2-stage hydrogen flame arrestor.   The mass flow
controller used previously to control  2H2/CO fuel  was eliminated
from the fuel delivery system.   This caused the engine to operate
at rich conditions when gaseous  fuel was used.

     The cylindrical plenum used previously to distribute fuel flow
to each cylinder was replaced  with  a 1/4-inch diameter fuel rail.
The fuel rail would distribute the  incoming fuel  to  each of four
flexible fuel lines 3 inches in length  leading to the fuel injector
ports.   The total  length from the intake valves  to the  flame
arrestor was approximately 11  inches.

     The  four fuel  lines are  connected  to the same  threaded
fittings which are screwed into the fuel  injection posts in the
valve  control assembly.   The inside  diameter of  these  fittings
(previously 1/4-inch)  were replaced with different nozzle designs
to increase fuel  pressure and enhance the fuel distribution.   A
nozzle opening of 3  millimeters was used  in this testing.   The
gaseous fuel is supplied to the combustion chambers by the opening
of the fuel valves when the blockages in the intake  air control
assembly were present.  With  these blockages,  fuel flow to the
engine occurred through one intake valve and air through the other.

IV.  Exhaust Measurement Procedure

     Dilute emission samples were taken during this latest phase of
testing.  Dilute  emission samples were engine-out levels and taken
downstream of the exhaust manifold. These samples were  taken as
engine  exhaust  passes  from  the exhaust  pipe  to  a 2-1/2  inch
diameter  flexible metal  tube.    This  tube  passes  the  exhaust

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                               -6-


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  approximately  40 feet.

     A  gaseous sample  line has  been  extended through  the cell
ceiling and  connects 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.  Hydrocarbons (HC)  emissions were measured with
a Beckman  Model 400 flame  ionization detector (FID).   NOx level
determination was conducted on a Beckman model  951 chemiluminescent
NOx analyzer.  Carbon oxides (CO, CO2)  were  measured by infrared
technique using a Horiba Model A1A23 infrared  analyzer.

V.   Discussion of Teat Results

     The goal of  this  last phase of testing  was  to  operate the
engine  on  M100 neat methanol and simulated  dissociated methanol
(2H2/CO)  fuels over  a  wide  range  of  operating conditions  to
determine  if there were operating conditions  on 2H2/CO fuel that
were comparable to M100 power output,  CO emissions, and combustion
efficiency levels.  First,  testing was conducted at both 2,000 and
1,500 rpm when  the engine  load was varied from idle to wide-open-
throttle (WOT)  with  A/F ratio also being varied.   The engine was
then converted to operation on 2H2/CO fuel while utilizing the stock
intake camshaft.  Because  each cylinder of fuel would operate the
engine for about 10-15 minutes,  only selected operating conditions
were  used  here.   Similarly, only a  limited  test sequence  was
followed when the  stock intake  camshaft was  replaced with  the
modified version for 2H2/CO fuel use.  The spark timing for testing
.on M100 fuel was kept at 20°BTDC; similarly,  with 2H2/CO fuel, the
spark timing was kept  at 5°BTDC.   Fuel pressure with M100 was 45
psig, and 75 psig with 2H2/CO.  Only selected operating points were
selected where the engine ran very smooth when 2H2/CO fuel was used.

     Figure  2 below  presents  brake specific  torque results while
using either fuel at 2,000  rpm.  The horizontal axis represents the
percentage   of  throttle opening  (100  percent throttle  opening
represents   WOT).    Also,   this  data  was  obtained  under  rich
conditions- of Lambda equal to 0.7.  From this plot, brake specific
torque during low load operation  (25 percent throttle opening) is
higher with  the 2Hj/CO  fuel than with M100.   During  medium load
operation  (40-65 percent throttle opening),  only a slight torque
deviation from M100  levels results when operating on the gaseous
fuel with the stock  intake camshaft.  Using the modified camshaft
results in a larger drop in brake specific torque at higher engine
loads.  At WOT, there is  about a 20  percent  difference in power
output between  the two fuels using the stock camshaft.  Operation
with the modified camshaft resulted in leaner operating conditions
because of the  reduced fuel valve lift and duration.

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                              -7-
                             Figure 2
                 Brake Specific Torque Values
         Lambda = 0.7, 2000 rpm Operating Conditions
           Torque (ft-lbs)
        120


        100


         80


         60


         4O


         20
         Camshaft/Fuel

        — Stock/M100

        -°- Stock/H2CO

        •»• Mod./H2CO
                  25      50     75

                   Throttle Opening (%)
100
     These trends in brake specific torque were also noted during
similar testing at 1,500 rpm.  Again, these results were obtained
at rich  conditions  of a Lambda equal  to 0.7.   Also,  at lighter
loads below  30 percent throttle  opening, brake  specific torque
levels with the  gaseous fuel and the  stock  intake camshaft were
larger than corresponding M100  levels.   At these conditions,  the
modified camshaft testing  also yielded similar  torque levels  as
M100 fuel.  During medium  load testing,  torque values associated
with 2H2/CO fuel use  begin  to fall below M100 levels.   With  the
stock camshaft,  torque  values are only slightly lower than M100
levels,  but  using  the  modified  camshaft  has  an  even  more
detrimental affect on torque.  Above 75 percent throttle opening,
torque value* associated with 2H2/CO fuel fall well below M100 fuel
levels.   At  WOT,  the  stock camshaft  testing yielded  a torque
approximately  53 percent below M100  levels.  This  reduction  in
torque may be attributable  to not adjusting the spark timing  for
changes in air/fuel richness at higher load conditions.

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                                  -8-
                               Figure 3
                    Brake Specific Torque Values
          Lambda = 0.7*, 1500 rpm Operating Conditions
          100
           80
           60
           40
           20
             Torque (ft-lbs)
         Camshaft/Fual

        -~Stock/M100

        •°-Stock/H2CO

        -*- Mod./H2CO
             0      25     50      75

                      Throttle Opening (%)

       * Operated slightly leaner with modified camshaft
100
     The second goal of this test program was to determine if there
were operating conditions  with 2Hj/CO fuel that  produced less CO
emissions  than with M100.  As was the case with torque output, CO
emission levels were indeed comparable between 2HJ/CO fuel operation
and M100 at some operating  conditions.  Figure 4 below presents CO
emission levels in grams/BHP-hr over a wide range of load operation
for each fu«l^at  2,000 rpm.

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                                -9-
                              Figure 4
            Brake Specific Carbon Monoxide Emissions
           Lambda = 0.7, 2000 rpm Operating Conditions
          500
          400
          300
          200
          100
             BSCO (g/Bhp-hr)
         Camshaft/Fuel

       — Stock/Ml 00

       •*• Stock/H2CO

       •*• Mod./H2CO
                   25     50      75

                     Throttle Opening (%)
100
     At  light  loads  (25  percent throttle  opening),  both fuels
produced a large amount of CO emissions.  However, when using the
gaseous  fuel, CO  emissions  at light loads were  about 29 percent
ftigher than M100 levels.  During medium load operation, CO levels
with 2H,/CO fuel dropped below the light-load M100  levels. However,
with the stock intake camshaft, the difference in  CO levels between
M100 and 2H,/CO  fuels  at each operating point remained similar to
the  difference  during  light-load  operation  (about  30 percent).
However, when the modified  intake  camshaft was  used,  CO levels
between  the two  fuels were  approximately equal at  a throttle
opening of 66 percent.

     Figure £ presents CO emission levels from testing at  a 1,500
rpm  engine  speed.   During this testing, operating on 2Hj/CO  fuel
resulted in higher CO emission levels for every operating condition
investigated.  CO levels with M100 fuel at 1,500 rpm were also  much
lower  than  when operating at  2,000 rpm.  With  the stock intake
camshaft and 2H2/CO fuel,  CO emission levels remain  approximately
twice as large as corresponding M100 levels over  the  entire engine
load range  investigated.   Below 75 percent throttle opening,  the
use  of the modified camshaft resulted in higher  CO emissions  than
the  stock camshaft.

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                                 -10-
                                Figure 5
             Brake Specific Carbon Monoxide Emissions
           Lambda = 0.7*, 1500 rpm Operating Conditions
           600

           500

           400

           300

           200

           100
              BSCO (g/Bhp-hr)
         Camshaft/Fuel

        ~-Stock/M100

        -°- Stock/H2CO

        -*• Mod./H2CO
              0       25      50     75

                      Throttle Opening (%)

         Operated slightly leaner with modified camshaft
100
     Obtaining lower CO levels with 2H2/CO fuel than with M100 seems
to be very difficult.  Although torque levels were greater at some
operating points  with 2H2/CO  fuel, it was not possible  to obtain
lower CO  emissions with this fuel when compared to  M100 levels.
This could be partly  attributable  to unburned fuel  and incomplete
combustion, both contributing to CO  formation when  2H2/CO fuel is
used, especially  at rich conditions.  With N100, only incomplete
combustion contributes to this phenomenon.   Also,  during testing
with the gaseous fuel, it was not possible to  fully warm the engine
prior to  emissions testing because of the limited  amount of fuel
present  irv the gas bottle.   The engine oil temperature during
emissions  tasting with  M100  fuel  was about  180-200°F;  the
corresponding temperature with 2H2/CO fuel was  90-120°F.  Therefore,
the  combustion chamber was  much  colder,  resulting in  greater
amounts   of   unburned   fuel  and   incomplete   combustion,   both
contributing to higher CO emissions.

     The  last goal in this test program was to operate the engine
on 2H2/CO  fuel at a greater combustion efficiency than when operated
on M100.    Figure 6  below presents  combustion  efficiency values
over the  same engine load range  at 2,000 rpm  and Lambda  = 0.7
conditions.

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                                -11-
                               Figure 6
                  Brake Thermal Efficiency Values
           Lambda = 0.7, 2000 rpm Operating Conditions
             Efficiency (%)
          30


          25


          20


          15


          10
         Camshaft/Fuel

        •~Stock/M100

        -°- Stock/H2CO

        •*• Mod./H2CO
                   25      50      75

                     Throttle Opening (%)
100
      Combustion  efficiency  was calculated  based  on the  brake
horsepower output, fuel consumption, and heat of combustion of the
fuel used by the  following  formula:[6]
       =  [BHP x
Where:
     H   = Brake thermal efficiency
     BHP = Brake horsepower
     K,,  = Value of 1 hp expressed in (force x length/time)
           units
      J  =•• Joule's law constant
     Mf  * Macs of  fuel  supplied  per  unit time
     Qe  » Heat of  combustion of  a unit mass of fuel.

     Low load operation below 30 percent throttle opening using the
2Hj/CO  fuel with the stock intake camshaft resulted in higher brake
thermal efficiency values than when operating on M100.  At greater
loads with the stock intake camshaft,  brake efficiency values begin
to diverge below corresponding M100 levels, resulting  in about a 10
percent thermal efficiency difference at WOT operating conditions.
Again, this plot is only for rich operating conditions of Lambda -
0.7.

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                                 -12-
     Testing  with  the  modified  intake camshaft  also  provided
operating points where the engine was more efficient operating on
gaseous  fuel  than with M100.   At about half throttle,  the brake
thermal  efficiency  when operating  on  2H2/CO  fuel was  slightly
greater  than  the M100  efficiency curve.  However, as  the engine
load was increased,  efficiency values  with the modified intake
camshaft  dropped   substantially.     However,   there  again  were
operating conditions at Lambda = 0.7, 2,000 rpm  where  the engine
was more efficient  operating  on 2H2/CO fuel.

     Figure 7 presents similar traces of brake  thermal  efficiency
for each fuel, however, when operating at 1,500 rpm.  Again, below
a throttle opening  of about 40 percent  (low load),  brake thermal
efficiencies were greater when operating on 2H2/CO fuel rather than
M100.  This was the case for both the stock and  modified camshaft.
During  middle to  full  load  operation,  brake  efficiency  values
dropped  off  considerably  from corresponding M100  levels.   This
efficiency drop may again be attributed to not adjusting the spark
timing when the engine was operated at leaner conditions here.  At
WOT, a thermal efficiency difference of 15 percent results between
operation on the two fuels.   However,  at lower  loads, the goal of
higher  brake  thermal  efficiencies on  dissociated methanol  fuel
operation was realized.
                               Figure 7
                   Brake Thermal Efficiency Values
           Lambda = 0.7*, 1500 rpm Operating Conditions
             Efficiency (%)
                                                   Camstaft/Futf

                                                  ~Stock/M100

                                                  -°- Stock/H2CO

                                                  * Mod./H2CO
                    25      50      75

                      Throttle Opening (%)

        * Operated slightly leaner with modified camshaft
100

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                               -13-


     Again, all the previous figures' results were obtained at rich
operating conditions (Lambda = 0.7).  This was the case because the
fuel controller used previously  during  2H2/CO fuel  operation was
eliminated from the fuel delivery system.   An air/fuel ratio was
used to monitor  richness  with  both fuels.    The  stock  intake
camshaft always allowed the engine to operate at a Lambda value of
0.7 at  a  fuel delivery pressure of  75  psig.   However,  when the
modified intake camshaft was  used,  engine  operation  became much
leaner,  varying anywhere between a Lambda  value  of 0.8 to 1.1,
depending  on  throttle  position.    The air/fuel  richness  when
operating on M100 was controlled by an external controller provided
to us by Nissan.   The air/fuel value would  be changed by turning
the dial  and monitoring the Lambda  value  on the air/fuel  ratio
meter.

     Appendix  B  of  this report  contains all  the power  output,
efficiency, and emissions data from testing on M100  fuel at both
2,000 and  1,500 rpm conditions.   The test  sequence  started with
selecting the WOT condition, and emission bag samples  and  torque
values were  taken at  three  different fuel  richness  points:  rich
(Lambda = 0.7), stoichiometric (Lambda = 1.0), and lean (Lambda =
1.4). Four throttle openings were evaluated; 100 percent (WOT), 75
percent,  50 percent,  and  25  percent  throttle openings.    All
emissions values are presented in brake specific  form  (grams per
brake horsepower-hour)  and  are engine-out  levels;  there was no
catalyst present  in  the exhaust system.

     When  operating on M100,  the  engine  produced  much  higher
emissions levels  of  hydrocarbons and CO at rich conditions (Lambda
=0.7).   At  rich conditions, these  levels were  approximately ten
times higher than when  operating at stoichiometric.   The largest
brake specific horsepower was  obtained at WOT and  rich conditions
and was  measured  at  39.2 at 2,000 rpm.  The greatest brake thermal
efficiency on M100  fuel was 36.3 percent at WOT, lean operation
(Lambda = 1.3), and  2,000 rpm.  Similarly,  the highest efficiency
at 1,500 rpm was  also noted  at this same operating point.

     Appendix C presents similar data when operating on  2H2/CO fuel
with the stock and modified  intake camshafts.  Again,  the limited
amount of fuel in the gas cylinders allowed for data collection at
only a  few test  points (indicated by percent throttle opening).
The overall goals of operating  on 2H2/CO fuel  at higher efficiencies
and torque were realized at low load operation.  This, however, was
not the  case at higher loads.    Operating  on 2H2/CO  fuel  while
producing  lower  levels of CO  emissions were more  difficult to
attain.   Because of the CO content in the fuel itself, operating on
dissociated methanol always produced more CO  emissions than M100 at
the same operating points.  However, through the recent engine and
fuel system modifications described previously, CO levels produced
during  2H2/CO  fuel  operation  here were  much  lower  than  those
produced anytime  previously.[1]

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                               -14-
     In the  prior interim report,[l] the  combustion process was
monitored using  an in-cylinder pressure transducer.  Previously,
engine  operation on dissociated  methanol  fuel was smoother and
offered less fluctuation in maximum  cylinder  pressure values  (a
more stable combustion process).  It was again attempted to monitor
this data, however, error and resonance  in  the pressure transducer
did not allow for accurate data presentation.

VI. Future Efforts

     A 100 percent efficient methanol dissociator  is currently not
available.  The initial goal of this  engine conversion project was
to  convert  an  MIOO-fueled  engine   to operation   on  simulated
dissociated methanol fuel. The engine is currently able to operate
on 2H2/CO fuel at higher power output and greater thermal efficiency
than when fueled with  M100  at certain operating conditions.  EPA
does not  plan any additional engine  testing until  an acceptable
methanol dissociator becomes available.

VII. Acknowledgments

     The CA18DE  engine described  in  this report was modified for
use with M100 neat methanol and loaned to EPA by the Nissan Motor
Corporation as support  for an effort to investigate the potential
of neat methanol as an  alternative motor vehicle fuel. The authors
appreciate the efforts  of Jennifer Criss and Mae Gillespie of the
Technology Development  Group for word processing support.

VIII. References

     1.   "Conversion   Of  Methanol-Fueled  16-valve,  4-Cylinder
Engine  To Operation On Gaseous 2H2/CO Fuel-Interim Report IV,"
Schaefer,  R. M., et al., EPA/AA/TDG/92-06,  September 1992.

     2.   "Conversion   Of  Methanol-Fueled  16-Valve,  4-Cylinder
Engine  To Operation On Gaseous 2H2/CO Fuel-Interim Report II,"
Piotrowski, G. K. and J. Martin, EPA/AA/CTAB/89-02,  March 1989.

     3.   "Resistively Heated Methanol Dissociator For Engine Cold
Start Ass 1st-Interim Report," Piotrowski, G. K., EPA/AA/CTAB/88-02,
March 1988.-  -,
     4.   "Conversion  of  Methanol-Fueled  16-Valve,  4-Cylinder
Engine To  Operation On Gaseous  2H2/CO  Fuel-Interim  Report III,"
Schaefer, R. M. et al., EPA/AA/CTAB/91-01, April 1991.

     5.   "Conversion  of  Methanol-Fueled  16-Valve,  4-Cylinder
Engine  to  Operation  On  Gaseous  2H2/CO  Fuel-Interim  Report,"
Piotrowski, G. K., EPA/AA/CTAB/88-06, June 1988.

     6.   The Internal ^-Combust ion Engine  in  Theory and Practice.
Volume 1. Taylor, C. P., The M.I.T. Press, 1985.

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                               A-l
                           APPENDIX A
         TEST ENGINE SPECIFICATIONS, M100 FUEL  OPERATION
              CONDITION AS  LOAN BY  NISSAN TO  EPA
Manufacturer
Basic engine designator
Displacement
Cylinder arrangement
Valvetrain
Combustion chamber
Bore X Stroke
Compression ratio
Compression pressure
Fuel control system

EGR
Valve clearance
Idle speed
Engine oil

Fuel
Air/fuel control

Spark advance control
              Nissan Motor Co., LTD
                             CA18DE
                            1809 cc
                4-cylinder, in-line
             Dual-overhead camshaft
                    Pentroof design
                    83 mm x 83.6 mm
                               10.5
  16.5 kg/square cm (350 rpm, 80°C)
          Electronically controlled
                     fuel injection
                       EGR not used
     0 mm (automatically adjusting)
                            750 rpm
    Special formulation supplied by
                Nissan for methanol
                   engine operation
                 Ml00 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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        B-l




   APPENDIX B






MIPOTESTRESULTS
2,000 RPN Conditions
Lambda
Torque
(ft-lb)
g/BHP-hr
BSHC
BSCO
BSNOX
BSCO
Effic.
(%)
BHP
Wide-Open Throttle:
0.7
1.0
1.3
103
94
78
10.37
0.45
0.64
229.7
37.5
3.9
3.9
9.1
4.6
399
448
466
28.2
35.2
36.3
39.2
35.8
29.7
75 Percent Throttle opening:
0.7
1.1
1.4
62
58
40
15.64
1.42
1.62
244.6
22.0
3.5
0.9
6.6
1.2
404
557
589
23.2
31.9
27.9
23.6
22.1
15.2
50 Percent Throttle Opening:
0.7
1.1
1.4
44
36
22
2.66
0.41
3.63
203.3
6.3
6.9
0.2
3.6
1.0
404
599
776
22.0
26.7
21.0
16.8
13.7
8.4
25 Percent Throttle Opening:
0.7
1.0
1.4
6
6
0
8.64
1.32
NA
346.2
22.6
NA
0.8
1.2
NA
1595
1762
NA
6.2
8.4
0.0
2.3
2.3
0.0
NA = Not available

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        B-2
APPENDIX B (cont'd)
 Ml00 TEST RESULTS
1,500 RPM conditions
Lambda
Torque
(ftlb)
g/BHP-hr
BSHC
BSCO
BSNOX
Wide-Open Throttle:
0.7
0.1
1.4
93
85
69
25.35
2.88
1.18
133.8
16.9
2.7
5.5
10.1
3.2
BSCOj
Effic.
(%)

428
457
461
24.7
30.7
35.0
BHP

26.6
24.3
19.7
75 Percent Throttle Opening:
0.7
1.0
1.4
62
58
40
26.44
1.43
1.40
140.3
16.6
2.4
1.9
7.2
1.9
428
510
561
22.1
28.3
27.3
17.7
16.6
; 11.4
50 Percent Throttle Opening: :
0.7
1.0
1.4
45
37
25
3.87
1.08
1.87
147.9
7.2
1.8
0.3
4.2
0.9
393
576
536
21.8
24.4
23.0
12.9
10.6
7.1
25 Percent Throttle Opening:
0.7
1.0
1.4
10
11
2
5.01
0.94
16.60
168.1
14.1
15.0
0.4
1.2
1.9
851
1024
4177
9.8
14.3
3.9
2.9.
3 . i ;•
0.-6
i

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       C-l
    APPENDIX C
2H,/CO TEST RESULTS
Stock Intake Comshaf t Testing
%WOT
Torque
(ftlb)
g/BHP-hr
BSHC
BSCO
BSNOX
BSC02
Effio
(%)
BHP
2,000 rpm
25
50
53
56
12
36
42
42
0.22
0.07
0.02
0.04
445.0
288.0
284.9
283.3
0.2
0.8
0.2
0.4
524
415
394
443
11.0
16.6
19.6
17.0
4.6
13.7
16.0
16.0
1,500 rpm
33
.. .-• 59,
100
28
48
44
0.01
0.04
0.03
308.2
269.5
285.1
0.1
0.7
0.2
336
394
358
16.8
16.4
8.9
8.0
13.7
12.6
Modified Intake Camshaft Testing
Lambda
%WOT
Torque
(ftlb)
g/BHP-hr
BSHC
BSCO
BSNOX
BSCO2
Effic
(%)
BHP
„ 2,000 rpm ....... : ...
l.l
0.9
46
66
1,500 rp»
1.1
0.8
32?
74
29
36
0.03
0.02
317.9
241.3
17.1
13.1
676
624
21.4
15.3
10.9
13.7

18
43
0.06
0.05
485.2
253.1
4.6
21.7
688
618
16.6
12.8
5.1
12.3

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