EPA/AA/TDG/93-04
                         Technical  Report
              Conversion of  Methanol-Fueled  16-Valve,
            4-Cylinder Engine To Operation On Gaseous
                    2Hj/CO Fuel - Final Report
                                by
                        Ronald M.  Schaefer
                         Fakhri J.  Hamady
                         janes 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  itt the  release of  such  reports is  to facilitate  the
exchange oC 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

-------
                        Table of Contents
                                                            Pag*
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
VI 1 1. References ........................ 14
APPENDIX A - Test Engine Specifications ............ A-l
APPENDIX B - M100 Test Results ................ B-l
APPENDIX C - 2H2/CO Test Results  ............... C-l

-------
I.

     A 16-valve, 4-cylinder light-duty automotive engine has been
converted to  operation on a mixture  of  hydrogen (H1)  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 2Hj/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 tte stock intake camshaft was utilized  with 2Hj/CO fuel,
torque value* 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 N100 levels more rapidly,  perhaps due  to the very
short fuel  valve event.   However, there were several operating
conditions when using 2Hj/CO fuel  that resulted  in higher torque
values than were achieved with M100 fuel.

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

-------
                               -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 2H2/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'a.

     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  Hj and  CO gases according  to  the
reaction:
                        COW


     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
CA180E  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

-------
                                -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 Hj  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 IHQO 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 allov 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.

-------
                                -4-
                             Figure 1

               simulated Direct Injection Operation
                 VaIve Scheme For 2&/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 tfi*  admission   of  air to the ports through  which the
gaseous fiurl passes.  The hole  in the assembly  left by the power
valve slid* vac sealed to prevent leakage of fuel and air between
runners.

     With 2Ha/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

-------
                                -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 l/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 f ue^ 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.
     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

-------
                               -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 Test  Results

     The  goal of   this last phase of testing  was to  operate the
 engine on M100 neat methano1 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 21^/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 20BTDC;  similarly,  with 2^/00 fuel, the
'spark timing was  kept  at 5BTDC.   Fuel pressure with  M100 was 45
 psig, and 75 psig  with 2Hj/CO.  Only selected  operating  points were
 selected where the engine ran very smooth when 2Hj/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
 represent* . WOT).     Also,   this  data  was  obtained  under rich
 condition** of: Lambda equal to 0.7.  From this plot, brake specific
 torque during low load operation  (25 percent throttle  opening) is
 higher wits  the 2Hj/CO  fuel than with M100.   During  medium load
 operation (40-65  percent throttle opening),  only a slight  torque
 deviation froa  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.

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


         100


         80


         60


         4O


         20
         Ctmstaft/Furt

        Stock/Ml 00

       + 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
MlOO fuel.   During medium load testing, torque  values associated
with 2H7/CO  fuel us*  begin to fall below MlOO levels.   With the
stock camshaft,  torque values are only  slightly lower  than  MlOO
levels,  but, using  the  modified  camshaft  has  an  even  more
detrimenta-1. affect on torque.  Above  75  percent  throttle opening,
torque value* associated with 2Hj/CO fuel fall well below MlOO fuel
levels.   Afe HOT,  the  stock  camshaft testing  yielded  a  torque
approximately  53 percent, below  MlOO  levels.   This  reduction in
torque may be  attributable to not adjusting the spark timing for
changes in air/fuel richness at higher load conditions.

-------
                                 -8-
                               Figure 3
                    Brake Specific Torque Values
          Lambda = 0.7*, 1500 rpm Operating Conditions
          100


           80


           60


           40


           20
             Torque (ft-lbs)
         dmitaft/Futf

       ~-Stock/Ml 00

        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 2H7/CO  fuel that produced  less CO
emissions than with M100.  As was the case with torque output, CO
emission levels were indeed comparable between 2^/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 fusfrat  2,000 rpm.

-------
                                 -9-
                               Figure 4
            Brake Specific Carbon Monoxide Emissions
           Lambda = 0.7, 2000 rpm Operating Conditions
          500
          400
          300
          200
          100
            0
             BSCO (g/Bhp-hr)
         Camstaft/Fud

       ~ 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  th  two  fuels  were approximately  equal  at  a throttle
opening  of 66 percent.

     Figurx * presents CO emission  levels from  testing at  a 1,500
rpm  engine speed.   During this testing,  operating on 2H,/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  2H,/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.

-------
                                 -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 2H,/CO fuel than with M100 seems
to be very difficult.  Although torque levels were greater at some
operating points  with 2Hj/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  2Hj/CO fuel is
used, especially  at rich conditions.   With M100, 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  iit th gas bottle.   The engine oil temperature during
emissions  testing with  M100  fuel   was about  180-200F;  the
corresponding temperature with 2H2/CO fuel was  90-120?.  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 2Hj/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.

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


           25


           20


           15


           10
         Camsftaft/Ful

       ^Stock/Ml 00

       -- 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:
     n   m Brake thermal  efficiency
     BHP * Brake horsepower
     K,  - Value of l hp expressed in (force x length/time)
           units
      J  ~ Joule's  law constant
     M,  * MM* of  fuel supplied per unit time
     Q,  * Heat of  combustion of a unit mass of fuel.

     Low load operation below 30 percent throttle opening using the
2H2/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.

-------
                                 -12-
     Testing with  the  modified  intake  camshaft also  provided
operating points where the engine was more efficient operating on
gaseous  fue>l than with M100.   At about half  throttle,  the brake
thermal  efficiency  when  operating  on  2^/CQ  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 2HJ/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 2Hj/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 (%>
                                                   Camataft/Fu*

                                                   Stock/M100

                                                   Stock/H2CO

                                                  *Mod./H2CO
                   25      50      75

                     Throttle Opening (%)

         Operated slightly leaner with modified camshaft
100

-------
                                -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 l.l,
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  fewt 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  2HJ/CO  fuel  while
producing  lover  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]

-------
                               -14-
     In the  prior interim report,[1] the  combustion process was
monitored using an  in-cylinder pressure transducer.  Previously,
engine operation  on dissociated  methanol  fuel was smoother and
offered learn 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 2Hj/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 Assist-Interim Report," Piotrowski, G. K., EPA/AA/CTAB/88-02,
March 1988_  ~
           Cr4ei
     4.   "O&nversion   of  Methanol-Fueled  16-Valve,  4-Cylinder
Engine To Operation On  Gaseous  2H2/CO  Fuel-Interim Report III,"
Schaefer,  R. K. 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-Combustion Engine in  Theory and Practice.
Volume l.  Taylor,  C. F., The M.I.T. Press, 1985.

-------
                                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, 80C)
          Electronically controlled
                     fuel injection
                       EGR not used
     0 mm (automatically adjusting)
                            750 rpm
    Special formulation supplied by
                Nissan for methanol
                   engine operation
                 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 0BTDC to 54BTDC by means
             of an external control

-------
        B-l




    APPENDIX B






Ml00 TEST RESULTS
2,000 RPM conditions
Lambda
Torque
(ft-lb)
g/BHP-hr
B8HC
B8CO
BSNOX
BSCO
Effio.
(%)
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
75 Pereent 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
39.2
35.8
29.7

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

-------
        B-2
APPENDIX B  (cont'd)
 M100 TEST RESULTS
1,500 RPM Conditions
Lambda
Torque
(ftlb)
g/BHP-hr
BSHC
BSCO
BSNOX
BSCO,
Effic.
(%)
BHP
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
428
457
461
24.7
30.7
35.0
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
3.1
0.6

-------
       C-l
    APPENDIX C
2H./CO TEST RESULTS
Stock Intake comshaft Testing
%WOT
Torque
(ftlb)
g/BHP-hr
BSHC
B8CO
B8NOX
BSCOj
Effio
(%)
BHP
2,000 rpa
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 rpa
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)
2,000 rpa
1.1
0.9
46
66
29
36
g/BHP-hr
BSHC

0.03
0.02
BSCO

317.9
241.3
BSNOX
BSCO,

17.1
13.1
676
624
Effio
(%)
BHP

21.4
15.3
10.9
13.7
1,500 rp
1.1
0.8
32
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

-------