-&-<) 2-00 2.
                                                 EPA/AA/CTAB/92-02
                           Technical  Report
            Evaluation of Resistively Heated Fuel Injection
           Technology to  Reduce Cold Start Emissions And Assist
            Starting/Driveaway of a Methanol-Fueled Vehicle
                                by
                       Gregory K. Piotrowski
                        Ronald M. Schaefer
                           March 1992
                              NOTICE

       Technical Reports do not necessarily represent final  EPA
 n2S £r- P°sltlon.s-  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, MI 48105

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               •
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

             ANN ARBOR. MICHIGAN  48105
                                                                     OFFICE OF
                                                                  ' AIR AND RADIATION
               JAN  8 1993
            MEMORANDUM
            SUBJECT:   Exemption  From Peer and Administrative Review
            FROM:
    Karl H.  Hellman, Chief
    Control  Technology and Applications  Branch
    1     "       '  '        -
            TO:
                •    ,           .   • ,' : -r,
    Charles L.  Gray, Jr., Director
    Emission Control Technology Division
                                                      .
                                                                             ,

                                                                              *
r*'
                 The attached report entitled "Evaluation of Resistiyely Heated
            Fuel Injection Technology to Reduce Cold Start Emissions'and Assist
            Starting/Driveaway of a  Methanoi-Fueledyehicle," EPA/AA/CTAB/92-	
            02,  provides  results from a program to evaluate  a  set of heated
            fuel injectors  on an MIOO-fueled vehicle in an  attempt to lower
            cold start emissions of  unburned, fuel  and/CO and to improve cold
          -:  startability and driveability.

          r       Since this, report is only  concerned with"the presentation of
            data and its  analysis and doesnotinvolve  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. '•'-'••	   .  	  ,	-

                                                      -f',"'"    1  
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                         Table  of  Contents
                                                            Page
                                                           Number
I.    Summary  ......................     1
II.   Introduction   ....................   2
III.  Description of Heated Injector Technology  ......   3
IV.   Description of Test Vehicle  .............   6
V.    Test Facilities and Analytical Methods   .......   6
VI.   Test Procedures ...................   7
VII.  Discussion of Test Results   ......... ....   7
      A.  Testing At 75 °F Ambient Conditions   .  ......   7
      B.  Testing At 55 °F Ambient Conditions ........  10
      C.  Testing At Lower Than 55 °F Ambient Conditions . .  15
VIII. Future Efforts  ...................  17
IX.   Acknowledgments .  . . .  ...............  17
X.    References  .....................  18

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  ;I.    Summary
               •                      ,                  ,.   ,   ,
       EPA evaluated a set, of resistiyely heated fuel injectors pn an
  M100 methanol-fuel,ed yehicl^  in  an_attempt  to  reduce cold  start
 remissions and  to ipprove engine  startability and driveability  at
 flower  ambient  ,, temperatures .    This technology  was  evaluated  at
 f several

                                                                          #"'

       The first test phase was performed at an ambient temperature
,     75°F oyer; fcfee, Federal £est Procedure .(FTP) CVS 75 cycle.  Three
JHvehicle configurations were  tested at this ^ambient temperature.
  The fir-st ^configuration, referred to asbaseline, used the new fuel
-injectors  without  resistive^  heatingapplied.      The  second
Iconf iguration .. utilized .the heated, fuel, .injectors with a  10-second
!''Prehe*t period before Bag l  cold start followed by 2  minutes of
  ?'°s1;~start .keatv.  The maximum, temperature  of the  heated area was
-:held  Constant  by  a_ temperature  controller  at   150°F.    This
  temperature may  not  represent the temperature of  the  fuel being
^sprayed from the injector, however.  The final  test configuration
,,utilized the, samet,10-second, preheat and  2-minute  post-start heat
-« periods with injector temperature controlled at 200°F.
". ',  .•••>•;.;!•;' -• " "', ^ ";  '  . ,*".y  ?' '*• JV* "^Jf^f*1**"; * '-if",   ~  T1'  "'i?
.s.    ; TJie 150°F injector temperature setting resulted in a  9 percent
'.reduction in levels ,of Bag 1  unburned fuel (CH3OH), an 11 percent
 i increase in IBag  1 CO levels,  and a 7 percent increase in  Bag l NOx
  levels, when.., compared  to  Bag  1 emission levels  noted when the new
  fuel injectors were utilized without...resistlye .tynat applied.  When
 .Qompared to baseline results€  Bag 1 levels of CO were unchanged and
  Bag 1 levels"of unburned fuel were .reduced 8_percent when a higher
,  injector temperature  setting  of  266°?  was used. However, at this
 h,ifher temperature setting, Bag  1 levels  of unburned fuel and NOx
  slightly increased from  levels measured during  the 150°F injector
  temperature setting testing.
   r  "'        '^I'fV '- ' ,  '  -'••. ,"n«;i -iff,! ,' !""v;»- ',51 -i? -|,,HJ  • •'"•'• ir'SJ"--1.; i i;,!]*1-', (; •"''11W7Pfff'"«,"'i'rjr'7-Jf"fF1.1'' iff iW'ilj. ' |>n ' '!" r,T (I*1; iff ] *'•«$ 'j *<-* " f " ;ii|sl' .i« '' .'I!1 ,[•''• "SV.TWMI
':' ;L   •  :'•'    ' -Vv:;'-!1   '''^^...'^-.•'^^•^••^               v.-^-v^:^-'^ >':/f:**;ill
       The yehicle  was  ..Jthen tested, .over,.,the,^FTE, at ,^5.«F. ambient..
 temperature conditions in  a cold room „ test ..cell..   Several preheat
 periods  and injector Jbemperature!  settings  were evaluated here.  The
 post-start heat period was kept constant at 2 minutes  for  this
 testing.  Exhaust methanol levels were not directly measured during
 this testing.  A  lb~second.preheat period at a maximum temperature
 setting  of  156°F_ resulted in the  greatest reduction of Bag 1 total
 hydrocarbons,  a "31 percent .reduction..from baseline  levels.   This
 same configuration also resulted in a slight reduction of Bag l CO
 levels.   This was  thf only configuration tested that resulted in
 lower than  baseline levels of  Bag l CO at 55°F ambient conditions.
  •'      ''"' ;;'  ;'; •• '•'••fr^-r^
       An  improvement in engine startability at 55°F was also noted.
 This engine had to  be  cranked for 15 seconds before it would start
 wjLth the  stpck  fuel   injectors   originally provided  by  Toyota.
 During each test conducted during this phase of testing  with  the
 heated fuel injectors, the engine started after less than 2 seconds
 of  cranking.


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                               -2-
      Previously,  the engine was  only  able to start after  a  so°F
 overnight soak when it was cranked for 1-1/2  minutes in 15-second
 increments.   The  use of the heated  fuel injectors reduced  this
 cranking period to 13 seconds when a 10-second preheat period prior
 to engine  cranking,  a 2-minute  heating period  after  cranking
 started,   and   an  injector  temperature  setting  of  150°F  were
 utilized. A higher temperature setting with the same heat periods
 did not  further lower the cranking time to start.  Engine roughness
 was noticeably reduced after a 50 °F soak when the  fuel injectors
 were  heated;  no attempt was made to quantify this  improvement  in
 dnveability,  however.

      The test vehicle was then soaked to 45°F.  The  engine started
 after approximately  1-1/2  minutes of cranking when  preheating and
 an injector temperature setting of 250°F were utilized.   Preheating
 was limited to  a 20-second period prior to cranking and continued
 during  the entire cranking  period.   However, when a  longer 30-
 second  heating period prior  to  cranking  and a  higher maximum
 temperature  setting of  350°F  were utilized, the  engine did not
 start after approximately  2-1/2 minutes of cranking.

 II.   Introduction

      Light-duty M100  neat methanol engines are difficult  to start
 and run  in  cold  weather  because of  the high boiling point  of
 methanol, methanol's high heat of vaporization (5.5  percent  of the
 heat  of combustion compared to less than  1 percent  for  gasoline),
 and the increased fuel flow needed for  methanol  (about double  that
 of gasoline).  Gasoline-fueled  engines  start with less  difficulty
 under the same  conditions  partly  because of the easily ignitable
 light ends of  this fuel such as  butanes,  which are vaporized  at
 relatively  low  temperatures.   Methanol  engines,   like  gasoline
 engines,  also emit much higher levels of unburned fuel  and carbon
 monoxide   (CO)  at   cold  start  as  cold  soak  temperature   is
 decreased.[1]

      Various attempts have been made to solve the integrated cold
 start/high emissions problems. Intake air and  fuel preheaters,
 heated carburetor/manifold spacers and intake  air  warmup stoves
 have  been used on production  and concept vehicles with varying
 degrees   of   success.  Recently,  resistively   heated   catalyst
 technology has been evaluated to reduce CO emissions  from gasoline-
 fueled vehicles at lower temperatures; this  technology does  not
 address  the  cold  start/drive issue  with methanol,  however.[2]
 Exhaust  heat storage  technology  is  being evaluated  by EPA to
 address  simultaneously  the  problems   of cold  start/drive  and
 elevated emission levels at cold start.[3]  Direct fuel injection
 into the cylinder has proven effective  as  a cold start assist to a
methanol-fueled vehicle at  low  ambient  temperature conditions.
 [4,5]

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      Resistively heating the fuel injectors in a multipoint  fuel
 infection system would have the advantage of adding heat energy to
 the  fuel immediately before induction to the cylinder.  A  minimum
 amount of time is therefore available for undesirable heat transfer
 from the hot fuel to the  surroundings prior to induction. While not
 affecting the mechanical process of the injection,  this additional
 heat may provide an assist to fuel atomization and fuel/air  mixing
 promoting cold  start.

      Unique Products Inc., located in Hazel Park, Michigan,  designs
 and   manufactures specialized  heated  products   for  engineering
 applications.  Among their products  are fluid sampling tubes  in
 which moving gases or liquids may be  kept at constant, elevated
 temperatures. EPA approached Unique  Products in March,  1991,  and
 requested that  Unique provide a set of heated fuel  injectors  for
 evaluation on a methanol-fueled vehicle. These injectors were to be
 fitted with Unique's  nichrome heating technology  and  insulated
 prior to their  installation  in the engine head.  Unique  agreed  to
 provide  a set of  heated  injectors  for evaluation by  EPA.

      EPA selected an M100 methanol-fueled Toyota Carina as the test
 vehicle  for this evaluation.  This vehicle was loaned to  EPA  by
 Toyota to assist EPA's alternative fuel emission control technology
 evaluations.[6]   Nippondenso,  the supplier to Toyota of the fuel
 injectors used  on the test vehicle,  provided EPA with a detailed
 drawing  of the injectors showing internal dimensions. This  drawing
 was  used by  Unique to  modify a  set  of injectors,  provided  by
 Toyota,  with Unique's resistive heating process.

      This  set  of  modified  fuel  injectors,  together  with  a
 controller  to regulate the power supplied to individual  injectors
 was  provided  by  Unique Products  to  EPA  for  evaluation.  The
 injectors were  installed  in  the test  vehicle,  and the car was
 emission tested several times  using different  injector heating
 schemes.  The results from this  testing are given below in this
 paper.

 HI-   Description of Heated Injector Technology

      The Unique Products heating process,  though proprietary,  is
 described in a sales brochure available from the manufacturer.[7]
 Nichrome wire heating elements are wrapped around the object to be
 resistively heated, and the elements are then covered with either
 a fibrous ceramic or silicone insulation. A flexible sheath  is then
wrapped  around  the insulation;  the  sheaths can  be made  from a
variety of materials,  depending upon the application.  A picture of
this process is provided in Figure 1 below.

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                                 -4-
                               Figure 1

                 Resistivelv Heated In-iector
                                 TEMPERATURE INSULATION
                             FOR EFFICIENCY AND USER PROTECTION
            MED.A TO BE
           TEMP MAINTAINED
                              -FLEXIBLE SLEEVING
                               AVAILABLE IN VARIOUS DUTIES
      The MlOO-fueled Toyota Carina test vehicle is equipped with a
methanol tolerant multipoint fuel  injection  system.^Jhe  fuel
       °ar   desined
                                                        .
             m  desitned ,for  use  with methanol fuels,  and  are
          to Toyota  by Nippondenso. Four  of these  injectors were
?echio?ogy.°    ***  Products to be fitted with  resistive Haling
TT«-  Th«  1?elL  inie
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                       -5-
                    Figure 2
       Resistivelv Heated Fuel Irnector
                    Figure 3
Resistivelv  Heated  Fuel Irnectors Controller1
           "iisKlHiigsiS-iB'nsS^lsii^^                -v-i ••''•'•' '  '" •'• :'"-


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                               -6-
 IV.   Description Of Test Vehicle

      The test vehicle is a 1986 Toyota Carina, powered by a 1587 cc
 displacement, 4-cylinder,  single overhead  camshaft engine   The
 engine has been modified for operation on methanol in  a lean burn
 mode,^ incorporating the lean mixture  sensor, swirl  control  valve
 and  timed sequential fuel injection of the Toyota Lean Combustion
 System  (T-LCS).  Modifications to  the fuel  system included  Se
 substitution of  parts resistant to methanol corrosion.  The exhaust
 catalyst is close coupled to the exhaust manifold, and  it consists
 of a typical three-way catalyst  formulation.   Details  of  this
 vehicle and its unique fuel system have been provided  in earlier
 professional and EPA technical reports.[1,6,8]

 v-    Test Facilities And Analytical  Methods

      EPA emissions testing at 75°F was  conducted on a Clayton Model
 ECE-50   double-roll   chassis  dynamometer  using  a  direct  drive
 variable inertia flywheel unit and a road load power control  unit.
 A  Philco  Ford constant volume  sampler with  a  blower having  a
 nominal capacity of 600 cfm was  used. Exhaust  HC emissions  were
 measured with a Beckman Model 400 flame ionization detector (FID)
 CO was measured using a Bendix Model 8501-5CA infrared CO analyzer.
 NOx   emissions  were  determined  with   a  Beckman  Model   951A
 chemiluminescent NOx analyzer.

      EPA emissions testing at a lower than 75°F ambient temperature
 is conducted on  a Labeco Electric single-roll chassis dynamometer
 using a direct-drive variable inertia flywheel unit and  a road load
 power control unit.    This  site utilized  a  Philco Ford constant
 volume  sampler that  has a nominal capacity of 350 cfm.   This  site
 used  emission analyzers similar to those in the 75°F test cell.

      Exhaust formaldehyde and methanol emission samples  could  onlv
 be measured  at  the   75°F  test site.   Exhaust  formaldehyde was
 measured  using a dinitrophenol-hydrazine  (DNPH)  technique.[9,10]
 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.

     The  procedure developed for  methanol  sampling and presently
 in-use employs water-filled  impingers  through which are pumped a
 sample  of  the dilute  exhaust or  evaporative  emissions.    The
methanol in the sample gas dissolves  in water.  After the sampling
period is complete, the solution in the impingers  is analyzed using
gas chromatographic  (GC) analysis.[11]

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                              -7-
     The  results for  M100 fuel  are computed  using  the methods
outlined in the "Final Rule For Methanol-Fueled Motor  Vehicles and
Motor Vehicle Engines," which was published in the Federal Register
on Tuesday, April 11,  1989.  Because  our cold room test cell  is not
equipped to measure methanol  and formaldehyde  emissions, methanol
results  from  the  lower  ambient  temperature  test  phases were
calculated from the measured  total hydrocarbon value.

VI.   Test Procedures

     This program had as its  goal the evaluation of a resistively
heated fuel  injection system to reduce  cold start emissions and
assist the cold startability and driveability of a methanol-fueled
vehicle.  The cold start emissions of interest were unburned fuel
and carbon monoxide.   Although formaldehyde emissions are also a
primary concern at  cold start,  these emissions were not measured
during testing at lower than  75°F ambient temperatures.  The cold
start  emissions  described  here were measured during the  Bag  1
portion of the FTP.  Bag 1  fuel economy levels  are also presented
in the discussion.

     The evaluation consisted of  three  distinct phases which are
discussed separately  in the  following section.   The  first phase
consisted of  emissions testing over the FTP  at  an  ambient soak
temperature of 75°F.  Baseline  (no resistive heating applied) and
heated injector testing were  both conducted at  this temperature.

     The second phase of this  evaluation  consisted  of emissions
testing  at a  reduced  temperature  of  55°F.   Startability  and
driveability during this phase are briefly discussed here.

     The  final  phase  consisted   of testing   when  the  ambient
temperature was reduced  below 55°F.   The ambient temperature was
lowered  in  5°F  increments  down  to  45°F.     Although  improved
startability was the primary concern here,  emissions  results are
also presented.  The test vehicle  had not previously started at an
ambient temperature below 55°F because it lacked a specialized cold
start system.

VII.  Discussion of Test Results

     A.  Testing At 75°F Ambient Conditions

     All test  results  here were generated over the  Federal Test
Procedure (FTP) cycle.  Bag 1  emissions are given in grams (g) over
the test segment  (Bag  1)  except  for  formaldehyde,  which  are
presented in milligrams (mg)  over Bag 1.  Composite FTP emissions
are given in grams per mile  (g/mi) except for formaldehyde,  which
are presented in milligrams per mile (mg/mi).

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                                 -8-
      During each test  phase,  several different injector  heating
schemes were evaluated.   First,  the "preheat"  periods (the  time
during which the   injectors  were  resistively  heated prior  to
starting  the engine in Bag l)  were varied.   The preheat periods
evaluated here were  0,  10,  and 20 seconds.   Another variable  for
this   evaluation was  the  maximum  temperature  setting  on  each
controller.   Most of the tests were run with this  setting at either
150«F or  200°F.   This  temperature does not  necessarily represent
the  temperature of  the fuel sprayed from the  injector, however;
this   was  the  temperature  of  the  thermocouple simulating   the
injector  outer wall temperature.  Each of  the four controllers  was
set at the same temperature setting.  The post-start heating period
was kept  constant  for each test at 2 minutes.   After two minutes
the  controller  was  turned  off,  and no  heat  was applied  to  the
injectors  for the  remainder of the FTP.

      Figure  4 below presents the Bag 1  exhaust  emission levels
measured during  testing at an ambient temperature of 75°F.  Three
configurations   were  tested  during  this  phase.     The  first
configuration was  baseline, with  no resistive  heating applied to
the fuel injectors.   The second  configuration used the resistively
heated fuel  injectors and a 10-second preheat  period at a maximum
temperature  setting  of  150°F.  The post-start heat period here was
2 minutes  for each heated injector test.  The  third configuration
also   utilized   a   10-second  preheat  period,   but  the  maximum
temperature  setting  was raised to  200°F.
                              Figure 4
                    Bag 1 Emissions, 75 Degrees F
                    Resistively Heated Fuel Injectors
       Injector Heating/Emissions

                    Methanol
                     Baseline
                  10PH-150F*
                   10PH-200F
                        CO
                     Baseline
                   10PH-150F
                   10PH-200F
                       NOxj
                    Baseline
                   10PH-150F
                   10PH-200F
                          0
      * 10 second preheat period
      Maximum temperature of 150 Degrees Fahrenheit.
2  4  6  8 10 12 14 16 18
   Bag 1 Emissions (grams)

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                               -9-
     The  use of injector heating appeared to have a very  limited
affect  on tailpipe  emissions  of  unburned  fuel.   Although  a 9
percent reduction  in methanol  emissions occurred with a resistive
heating   target  temperature  of  150°F,   a  further  increase  in
temperature resulted in slightly higher emissions of unburned fuel.
Bag  1  CO emissions  increased approximately 11  percent  when the
injectors were heated to 150°F.   This  testing was inconclusive,
however,  as  emissions decreased to baseline  (no injector heating)
levels when  the  injector temperature was raised to 200°F.

     NOx  emissions appeared to change little  through  the use of
injector  heating.   A slight upward trend  in Bag l NOx emissions
with increasing injector temperature was noted.  NOx emission rate
is  the only category  in  Figure  4  that  appeared to present a
consistent  trend  in  emissions with  increasing amounts  of  heat
energy applied to  the fuel  injectors.

     Table 1 summarizes Bag 1 emissions measured during testing at
an ambient temperature of 75°F.  All emission levels are presented
in grams except for formaldehyde, which is presented in milligrams.
Bag 1 fuel economy results are  also summarized here.

                             Table 1

           Resistively Heated Fuel Injector Evaluation
     Bag 1  Emissions/Fuel  Economy.  75°F  Ambient Temperature
                NMHC  OMHCE  THC  CH3OH   CO    NOx  HCHO
 Configuration    g     g     g     g     g      g    mg
MPG
1 Baseline
10 PH*, 150 °F
10 PH, 200°F
0.18
0.20
0.17
2.91
1.91
1.91
1.48
1.38
1.37
3.80
3.45
3.51
14.2
15.8
14.2
1.4
1.5
1.7
346
343
343
23.7
22.5
22.1
*  10-second preheat period

     Calculated organic material  hydrocarbon equivalents (OMHCE)
were reduced 34 percent,  from 2.91 grams to 1.91 grams, reflecting
the lower  emissions of unburned  fuel.  Total hydrocarbons (THC)
were reduced approximately 7 percent for both  injector temperature
settings.   Formaldehyde   (HCHO) emissions  were the same  for  all
injector configurations tested.   A 5 percent reduction  in Bag 1
fuel economy  (MPG)  was also  noted,  from 23.7 miles per gallon to
22.5 miles per gallon  for the lower injector temperature setting
tested.  The Bag 1 fuel economy decreased to 22.1 miles per gallon
an additional  2  percent  decrease from baseline, when the higher
temperature setting was utilized.

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                               -10-
     Table 2 is a summary of the FTP composite emission rates
 testing  at 75°F  ambient  temperature  conditions.   All  e

 ^iS>ar*'PreS?nte^^  grams per mile  excePt  for formaldehyde,
 which is given in milligrams per mile.  A summary of fuel
 over the FTP cycle for this testing is also given.
                              Table 2

            Resistively Heated Fuel Injector Evaluation
       Composite FTP Test Results. 75°F Ambient Temperature
                 NMHC  OMHCE  THC  CH3OH   CO    NOx     HCHO
  Configuration  g/mi   g/mi  g/mi  g/mi  g/mi  g/mi  mg/mi  MPG
  Baseline
0.01
0.15
                              0.11
      0.26
                         1.7
                                                 0.3
                               48
                                          23.8
  10 PH*,  150°F
0.01
0.15
0.10
0.25
                         2.0
                                                 0.3
                               48
                              23.1
                                                 0.3
 *  10-second  preheat  period.
                                     46
                                    22.9
     Generally, weighted FTP emissions were affected very little by
the use of injector wall heating.  For example,  Bag 1 emissions of
methanol  decreased 9 percent  when the injectors  were heated at
150°F; weighted  FTP emissions decreased slightly also.  However
when the  injector heating temperature was raised to 200°F, Bag i
methanol emissions rose slightly; weighted FTP emissions decreased
to 0.24 grams/mile.

     Calculated   OMHCE,  NMHC,   formaldehyde,  and  NOx  weighted
emissions over the FTP were not changed  when injector resistive
heating was used.  The 11 percent  increase in Bag l CO emissions,
resulting from heating the injectors to 150°F, was evident in the
weighted FTP emissions of 2.0 grams/mile.  The unexplained decrease
to baseline level CO when the injectors were heated to 200°F also
carried through  to the  return to  baseline level  of the weighted
average CO emissions.

        B.  Testing At 55°F Ambient Conditions

     Once the 75°F testing was completed, the  vehicle was tested in
a cold  room test cell  capable  of reducing  and  maintaining  the
ambient temperature during  an  FTP.   This  next  test phase  was
carried out at an ambient  temperature of  55«F.   This temperature
was selected  because the  test  vehicle was  not equipped  with a
special cold start system,  and difficulty  in starting this vehicle
below 55°F had been experienced previously.[1]

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                                -11-
     Figure 5 below presents Bag  1 calculated OMHCE emissions  for
various heating schemes evaluated during testing at 55°F.   Again,
10 PH denotes heat supplied to  the injectors for 10 seconds prior
to key  on.   Injector  heating was halted  2  minutes after starting
the engine  for each test.  The injectors were not heated during  the
remainder of the FTP.   Methanol emission levels are estimated here
according  to an  earlier procedure  because the test  cell did  not
have the  capability to measure methanol  emissions.   Formaldehyde
emissions  were  not  measured  in the  cold room,  and formaldehyde
emission levels are not presented here.
                                Figure 5
                   Bag 1 OMHCE Emissions, 55 Degrees F
                      Resistively Heated Fuel Injectors


         Injector Heating
                Baseline]


              OPH-150F*
              10PH-150F
              20PH-150F


               OPH-200F
              10PH-200F
                3.74
,', ,/'-. '.'•12.56

    ••/.• '  '12.73
           3.06
        2.7
                     0123
                              Exhaust OMHCE (grams)

         * 0 second preheat period
         Maximum temperature of 150 Degrees Fahrenheit.
     The  use of the new injectors without preheat, but with post-
start heating for 2 minutes at  150°F decreased OMHCE emissions by
approximately 25 percent.  Increasing the prestart heating period
appeared  to have only a minor effect, if any, on calculated OMHCE
emissions.  The use of  a 10-second heating period prior to engine
start  further  reduced  calculated OMHCE  emissions by  6  percent.
OMHCE  emissions  increased, however,  when the  preheat period  was
doubled in  length, from 10 seconds to 20 seconds.

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                                  -12-
      Increasing  the maximum injector  heating temperature to  200°F
 appeared to  change the Bag  l  OMHCE emission  rate little, if  any

 w??h 5?e ™£% *ea-8Ur«.ed  t* 15°°F-   Avera..••.-.• vv////////.v//777l20
     ..- • .'/// /////////////.'/121.1
                         122.9
                       ]21.6
                           5    10    15     20    25

                           Exhaust Carbon Monoxide (grams)
         * 0 second preheat period
         Maximum temperature of 150 Degrees Fahrenheit.
                                30
     CO  emissions  were measured at a  slightly  higher rate  than
baseline  when the  injectors  were heated  for 2  minutes at  150°F
following cold start.   Emissions  fell  to baseline levels when a
prestart  heating period was used,  yet  increased when the prestart
heating period was doubled. The variability in emission levels with
injector  heating convention,  and the closeness to baseline  for the
emission  levels  from  all conventions  evaluated  suggest that  the
effect of injector heating on CO emissions was minimal.

     Raising the  injector heating temperature  to  200°F  did  not
lower Bag l CO  emissions during the testing at  55°F conditions.
The  CO  emission  levels from  the  test  vehicle with either  200°F
heating convention exceeded the  level from baseline testing.

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                              -13-
   '  Table 3 below presents Bag 1 results for testing at an ambient
temperature of 55°F.

                             Table 3

           Resistively Heated Fuel Injector Evaluation
           Baa 1  Test Results.  55°F Ambient Temperature
NMHC OMHCE THC CH3OH CO NOx
Configuration g g g g g g MPG
Baseline
0 PH*, 150 °F
10 PH, 150°F
20 PH, 150°F
0 PH, 200°F
10 PH, 200°F
0.25
0.16
0.15
0.14
0.18
0.16
3.74
2.80
2.56
2.73
3.06
2.70
2.89
2.16
1.98
2.11
2.36
2.08
7.86
5.89
5.36
5.73
6.42
5.66
20.2
22.2
20.0
21.1
22.9
21.6
2.2
2.6
2.2
3.6
2.2
2.7
22.2
20.6
20.7
18.8
20.9
20.0
 * 0-second preheat period.
     Methanol  emissions were  estimated  from testing  conducted
according  to  gasoline-fueled  vehicle  procedures;  emissions  of
unburned fuel, therefore, follow a trend consistent with measured
hydrocarbons.  Bag 1 NOx levels increased significantly when a 20-
second prestart heating  period was  used with injector heating at
150°F; no unusual driving conditions or external occurrences were
noted during this testing,  however.   Bag 1 fuel economy  in all
cases was lower when injector  heating was used,  regardless which
injector  heating  convention  was used.   This  decrease in  fuel
economy, as well as the decrease in  fuel-related emissions, may be
related to changes in the physical characteristics of the fuel or
injector dimensions  caused by  the  injector heating.    More  work
would have to be done to determine the effect of injector heating
on these variables, as well as the effect on in-cylinder combustion
caused by injector heating.

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                               -14-
      Table 4 below presents all the  FTP  composite  emission rates
 for testing at a 55°F ambient temperature.

                              Table 4

            Resistively Heated Fuel Injector Evaluation
       Composite FTP Test Results. 55°F Ambient
NMHC OMHCE
Configuration g/mi g/mi
Baseline
0 PH*, 150°F
10 PH, 150°F
20 PH, 150°F
0 PH, 200°F
10 PH, 200°F
0.02
0.01
**
**
**
**
0.25
0.20
0.18
0.19
0.21
0.19
THC
g/mi
=^==
0.20
0.15
0.14
0.15
0.16
0.14
CH3OH CO NOx
g/mi g/mi g/mi MPG
0.53
0.42
0.38
0.40
0.44
0.39
2.2
2.3
2.2
2.4
2.6
2.3
0.4
0.5
0.5
0.7
0.4
0.5
23.4
22.1
22 2
21.2
22.6
22.1
*  0-second preheat period.
** Less than 0.005 g/mi detected.
     Generally, the trends in Bag 1 emissions with injector heating
carried over to  composite FTP  emissions.   For example, lower FTP
emissions of methanol and OMHCE were calculated as a result of the
lower Bag 1 emissions in these categories when any injector heating
convention was used.  The higher Bag 1 NOx levels also translated
into higher FTP NOx emissions.  The significant increase in Bag 1
NOx that  occurred when the prestart heating period  at 150°F was
doubled to  20 seconds was reflected in higher FTP NOx emissions.
The lower Bag 1 fuel economies  with  injector  heating also resulted
in FTP  fuel economies all  lower  than the baseline  (no injector
heating) level.

     Cold  startability at 55°F was improved  by the use  of the
resistively heated fuel  injectors.   The test  vehicle was not
equipped  with  a  dedicated  cold  start  system.    In  a  previous
evaluation,[1]  the vehicle would not start after an overnight soak
at lower than 55°F conditions.   At that time, the vehicle started
at 55°F only after an extended crank period.

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                               -15-
    During the present testing at 55°F, the vehicle started after
only a 1-2 second cranking period.   The vehicle ran very smoothly,
though not quantified here;  the cold temperature roughness noted
during  previous evaluations  was not  present.    The  technicians
conducting the driving tests noted a significant improvement in the
cold start driveability (run following start) of the vehicle at
55°F; no  attempt to quantify this  improvement was made, however.
This improvement in driveability was noted by the drivers even when
an  injector  preheating  period  was not  used  (injector  heating
limited to periods  following key-on/vehicle start).

     C.  Testing At Below 55°F Ambient Conditions

     Once the 55°F  emissions testing was completed, the test cell
temperature was  lowered to 50°F.   This vehicle  was  not  able to
start  following an overnight soak  at this  ambient  temperature
previously.[1]   During  this earlier  testing,   the  engine-start
attempt consisted of seven 5-second cranking periods, each followed
by a 10-second pause before cranking resumed.

     In an attempt  to improve cold startability, the resistively
heated  fuel  injectors were  tested over two  different operating
conditions.  The first consisted of a 20-second preheat period at
a 150°F injector temperature setting followed by a 2-minute heating
period after vehicle start.   The second configuration consisted of
similar 20-second preheat/2-minute post-start heating periods at an
injector  temperature  setting   of   350°F.     During  this  cold
startability evaluation,  a 5-second waiting period between cranking
would be utilized if the engine  failed  to start after 8 seconds of
cranking.  This cycle would be repeated until the  engine started or
five total cranking attempts were made.  During cranking and between
crank periods, the  injectors were to be resistively heated; it is
possible, therefore,  that the  prestart injector heating period
could be significantly extended beyond 20 seconds.

     With the 20-second preheat period and the 150°F injector
temperature setting,  the engine failed to start  on the first 8-
second  crank  period,  however,  it  started immediately upon  the
second attempt. Driveability problems during cold engine operation
were not  detected  during this  testing.   With the higher 350°F
setting and a  similar  preheat period,  the  engine would not start
during the first 8-second crank period.  The engine did start on
the second try,  however, but stalled  shortly thereafter.   This
stalling occurred two more times until the engine was able to start
and run on the fifth crank attempt.

     Emission  samples  were  collected during  testing  at  50°F for
these operating conditions.   Table  5 below presents these results.

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                                -16-
                              Table 5

            Resistively Heated Fuel Injector Evaluation
             Test Results.  5Q"F Cold Soak Temperature
   Configuration    NMHC  OMHCE  THC  CH,OH    CO
NOx   MPG
'Bag 1 (grams) :
20 PH*, 150 °F
20 PH, 350°F

0.28
0.31
4.50
4.83
3.47
3.73
9.43
10.13
24.4
22.3
FTP (g/mi) :
20 PH, 150°F
20 PH, 350°F
0.01
0.02
0.30
0.32
—
0.22
0.24
=^==
0.62
0.66
=====
2.4
2.1
=====;
3.8
3.7

0.7
0.5
18.3
19.9

20.8
23.8
 *  20-second preheat period.

     Both  Bag 1  and FTP composite  emission  levels of hydrocarbons
 and  CO  measured here  are greater  than levels  obtained during
 testing  at 55»F.  Higher Bag 1 and FTP hydrocarbon emission levels
 were also noted when the injector temperature setting was  increased
 to 350-F.  The higher emissions with the 350»F injector temperature
 setting  may be the result of a longer total  cranking time to start
 the engine.  The higher injector temperature setting also resulted
 in slightly lower Bag l CO levels, from  24.4  grams  to 22.3 grams.
 Fuel economy also  increased  with  the 350°F  setting.   The 150°F
 setting  resulted in a Bag 1  fuel economy value of  18.3 miles per
 gallon whereas the  higher temperature  setting resulted in a Bag l
 fuel economy value of 19.9 miles per gallon.  This Bag l  effect on
 fuel economy was also seen on  the overall  FTP fuel economy.  The
 higher temperature setting resulted in  a fuel economy of 23.8 miles
 per gallon,  over a  14 percent increase.

     After this testing was complete, the vehicle was soaked at an
 ambient  temperature  of  45«F.     The  same  starting  guidelines
 described  previously were also  utilized  here;  8-second  crank
 periods  followed by 5-second pause periods.

     The first attempt utilized a 20-second preheat period followed
 by 2 minutes of post-start heat. The injector temperature was set
 at 250°F for this testing.  On the  fifth  crank attempt, the engine
 started but  quickly stalled.   The engine was successfully started
 after 1-1/2 minutes of total crank time.  Cold start driveability
was very rough during the 2 minutes of post-start heat;  emissions
measurements  were   not  made  due  to   the  poor   driveabilitv
encountered.

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                              -17-


     The  next  cold start  attempt utilized  a  30-second  preheat
period  followed by  2  minutes of  post-start  heat.   The  injector
temperature  was  set  at 350 °F  for  this testing.    The  engine
attempted  to start during  the  fourth crank attempt, however,  it
stalled quickly thereafter.   After 2-1/2  minutes of  cranking, the
engine did not  start.

VIII. Future Efforts

     One possible future application  for this  resistive  heating
technology is to  heat the fuel line of a methanol-fueled  vehicle
during cold  start.  On a port fuel-injected vehicle,  the fuel line
could be heated from the engine compartment fire wall to the fuel
rail(s) .
     ^     heating scheme would have several advantages over merely
heating the injectors.  First, a much- larger heating surface area
is available; the amount of heat transfer to the cold fuel per unit
time could be significantly increased.  The insulation surrounding
the heating elements and the direction  of  fuel flow to the engine
would minimize unwanted heat transfer from the warmed fuel to the
environment.  Second,  the number of controllers might be reduced to
some number less than the four required  in the application here, a
considerable cost savings.  Fuel temperature might be more easily
controlled  because of  the ease in  locating a  fuel temperature
sensor in the fuel line versus  in an  injector  cavity.   Heating
element  durability might  be improved,  because a  lower heating
element temperature setting might be  possible due to the increase
in heat  transfer surface area.  Finally,  if  the heating element
fails, it may be less costly to replace  a covered fuel line than a
heated fuel injector(s) .

     One  serious  drawback  to  this application  would be  the
increased cost associated with the  additional heating element wire
and  insulation necessary  to cover  the increased  heat  transfer
surface area.   There is also the concern, real or  psychological, of
safety when a fuel system component is resistively heated.

     EPA  currently  has  not yet committed  to  future efforts with
this technology.

IX.   Acknowledgements

   The authors appreciate the efforts of James Garvey, Robert Moss,
Rodney Branham,  and  Ray Ouillette  of  the  Test and  Evaluation
Branch, ECTD,  who conducted the driving cycle tests discussed here.
The  authors also  appreciate the  efforts of  Mae Gillespie  and
Jennifer Criss for word processing and editing support.

     The  authors wish  to thank the Toyota Motor Corporation  for
supplying the MIOO-fueled Carina vehicle used in this testing.  The
assistance by the Nippondenso Corporation with the modification of
the fuel injectors was also greatly appreciated.

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                               -18-
 X.    References

      1.     "Evaluation  of  Toyota  LCS-M  Carina:     Phase  n »
 Piotrowski,  G.K.,  EPA/AA/CTAB/87-09,  December 1987.

      2.    "A  Resistively  Heated Catalytic  Converter  With  Air
 Injection  For  Oxidation  of Carbon Monoxide  and Hydrocarbons  at
 Reduced Ambient Temperatures," Piotrowski, G.K., EPA/AA/CTAB/89-06,
 September  1989.                                           .       '

      3.    "Evaluation of  a  Schatz  Heat  Battery Equipped  on  a
 Flexible-Fueled Vehicle,"  Piotrowski,  G.K.,   and R.M.  Schaefer,
 EPA/AA/CTAB/91-05,  September 1991.

      4.  "Development of a Direct  Injected Neat Methanol Engine For
 Passenger Car Applications," Rogers, G.,  et al., SAE  Paper 901521,
 1990.

      5.  "Unassisted Cold Starts to -29°C and Steady-State Tests of
 a  Direct-Injection, Stratified-Charge (DISC)  Engine Operated  on
 Neat  Alcohols," Siewert,  R.M.,  and E.G.  Groff, SAE Paper  872066,
 November 1987.

      6.  "Fuel  Economy and  Emissions of a Toyota  T-LCS-M Methanol
 Prototype Vehicle," Murrell, J.D., and G.K. Piotrowski,  SAE Paper
 871090, 1987.                                                 F

      7.   Sales  Literature, Unique  Products,  Inc.,  Hazel Park,
Michigan, 1991.

      8.    "Phase  I Testing  of  Toyota   Lean  Combustion  System
 (Methanol)," Murrell, J.D.,  and G.K. Piotrowski,  EPA/AA/CTAB/87-02,
January 1987.                                                    '

      9.   "Formaldehyde Measurement In Vehicle Exhaust At MVEL,"
Memorandum, Gilkey, R.L., OAR/OMS/EOD, Ann Arbor, MI, 1981.

    10.    "Formaldehyde   Sampling From  Automobile  Exhaust:    A
Hardware Approach," Pidgeon, W., EPA/AA/TEB/88-01, July  1988.

    11.  "Sample Preparation Techniques For Evaluating Methanol and
Formaldehyde Emissions From Methanol-Fueled Vehicles and Engines,"
Pidgeon,  W., and M. Reed, EPA/AA/TEB/88-02, September 1988.

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