-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).

This 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 M100-fueled Carina vehicle used in this testing. The
assistance by the Nippondenso Corporation with the modification of
the fuel injectors was also greatly appreciated.



-1ll-

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

i
Sse line I 3.74
}

OPH-150F* j2.8
10PH-150F|.___ Je. 56
20PH-150F| J2.73

OPH-200F ]3.06
10PH-200F| 27
to) 1 2 3 4

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.



Previously, the engine was only able to start after a 50°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
driveability, 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]



-18- -

x. References

1. “Evaluation of Toyota LCS-M Carina: Phase II,"
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.

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.



-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).

Cc. 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.



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.

viI. 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).



Figure 1

Resistively Heated Injector Process

HIGH TEMPERATURE INSULATION
FOR EFFICIENCY AND USER PROTECTION

Lh cems SLEEVING

AVAILABLE IN VARIOUS DUTIES

The M100-fueled Toyota Carina test vehicle is equipped with a
methanol tolerant multipoint fuel injection system. The fuel
injectors are designed for use with methanol fuels, and are
supplied to Toyota by Nippondenso. Four of these injectors were
supplied to Unique Products to be fitted with resistive heating
technology.

The fuel injectors were modified with a variation of the
Unique Products resistive heating technology. Fine nichrome wires
wrapped with silicone insulation surrounded the tips of the
injectors, providing resistive heating. A thin, rapid response J-
type thermocouple provided feedback temperature information to the
power controller for each injector. The heater/thermocouple
wrapping was coated with an aluminum epoxy, providing thermal
insulation. Four omron Model ES5C2 temperature controllers
controlled output voltage to the resistive heating elements. Figure
2 is a closeup of one of the heated injectors, showing the
electrical leads to the thermocouple and the heating elements.
Figure 3 is a picture of the box containing the controllers used
to regulate injector temperature.



-3-

Resistively heating the fuel injectors in a multipoint fuel
injection 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.

III. 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.



-16-

Table 5

Resistively Heated Fuel Injector Evaluation

Test Results, 50°F Cold Soak Temperature

Configuration NMHC OMHCE THC CH.OH co NOx MPG

‘Bag 1 (grams):

| 20 PH*, 150°F 0.28 | 4.50

E PH, 350°F 0.31 | 4.83 | 3.73 | 10.13 | 22.3 | 3.7] 19.9
FTP (g/mi): :

20 PH, 150°F 0.01 | 0.30 | 0.22 0.62 2.4 0.7 | 20.8

20 PH, 350°F

* 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 1 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 1
fuel economy value of 19.9 miles per gallon. This Bag 1 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 driveability
encountered.



-~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 the
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 only
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]



#¥20-R-92-00 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
decisions or positions. They are intended to present technical
analysis of issues using data which are currently available. The
purpose in the release of such reports is to facilitate the
exchange of technical information and to inform the public of
technical developments which may form the basis for a final EPA
decision, position or regulatory action.

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



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 1 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 issions/Fue onomy, 75° ient Temperature

NMHC OMHCE THC CH30H co NOx HCHO
Configuration g g g g g g ng MPG

Baseline
10 PH*, 150°F 0.20 | 1.91 | 1.38 | 3.45 | 15.8 1.5 343 | 22.5
10 PH, 200°F

* 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.



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 1) 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 3.8
10PH-150F*/77/77,13.45

10PH-200F) 3.51
co

Baseline 14.2
1OPH-150F[// Lpzl LLLT ILL TF) 15.8)
10PH-200F| ]14.2

NOx

Baseline 1.4
10PH-150F(77] 1.5
[1.7

10PH-200F|
0 2 4 6 8 10 12 14 16 18
Bag 1 Emissions (grams)

* 10 second preheat period
Maximum temperature of 150 Degrees Fahrenheit,



Figure 2

Resistively Heated Fuel Injecto:

Figure 3

Resistively Heated Fuel Injectors Controller





gS et ded 8 de a i
: . . vely heated fuel injectors on an
7 "M100 methanol-fue vehicle in an.attempt to reduce cold start
% Semissions and to improve engine startability and driveability at
: \s\lower ambient _temperatures. This technology was evaluated at

i ti

AE a BOR a Oe ae

"several different
: phase was performed at an ambient temperature

: of 75°F over the Federal Test Procedure (FTP) CVS 75 cycle. Three
‘;Vehicle configurations were tested at this ambient. temperature.
The first configuration, referred to as baseline, used the new fuel

:injectors without.

si heating applied. The second
the heated fuel injectors with a 10-second
Bag 1 cold start followed by 2 minutes of
1 temperature of the heated area was

held constant by a ten re controller at 150°F. This
u . » temperature may not represent the temperature of the fuel being
Sprayed from the injector, however. The final test configuration
. , utilized the, same 10-second, preheat and 2-minute post-start heat
ny al periods with inj

7 ae, 4 TI 2 dina 9 percent
an “sxeduction in levels of Bag 1 unburned fuel _(CH30H), an 11 percent
: ‘increase in Bag 1.CO levels, and a 7 percent increase in Bag 1 NOx
poe . levels when, compared to Bag 1 emission levels noted when the new
. »fuel injectors were utilized without resistive heat applied. When
compared 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 200°F was used. However, at this
‘higher temperature setting, Bag 1 levels of unburned fuel and NOx
Slightly increased from levels measured during the 150°F injector
temperature setting testin
: 5 woe Z

” The vehicle was then tested over the Fi t 55°F ambient __
temperature conditions in a cold room test cell. Several preheat
periods and injector temperature 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 10-second preheat period at a maximum temperature
setting of 150°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 1 CO
levels. This was the only configuration tested that resulted in
lower than baseline els of Bag 1 co at 55°F ambient conditions

ie wd ac Bah ey poe hae ke Meer
An improvement in engine startability at 55°F was also noted.
This engine had to be cranked for 15 seconds before it would start.
with the stock 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.



-12-

Increasing the maximum injector heating temperature to 200°F
appeared to change the Bag 1 OMHCE emission rate little, if any,
from the rate measured at 150°F. Average OMHCE Bag 1 emissions
with the 200°F injector temperature setting and the no preheat 2-
minute post-start heating conventions were 3.06 grams, higher than
emissions from any of the three 150°F injector temperature setting
and injector heating conventions evaluated. A 10-second preheating
period had the effect of reducing Bag 1 OMHCE emissions to 2.70
grams; this level was not below the OMHCE emission level using the
same injector heating convention at 150°F.

Bag 1 CO emissions at 55°F were affected very little by
injector heating. CO emission levels from this testing are
presented in Figure 6.

Figure 6
Bag 1 CO Emissions, 55 Degrees F
Resistively Heated Fuel Injectors

Injector Heating

8ase|ine i nas 20.2

OPH-150F*[2 TTT TTT ITLL TTF 22.2
VOPH-150F | AAT PLT L 20
20PH-150F, PP ITTELTTLTI LT LEE AANA
OPH-200F, __}22.9
10PH-200F| ]21.6
O 5 10 15 20 25 30

Exhaust Carbon Monoxide (grams)

* 0 second preheat period
Maximum temperature of 150 Degrees Fahrenheit.

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 1 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.



~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 Temperature

NMHC OMHCE THC CH30H CO NOx

Configuration g/mi__g/mi_g/mi_ g/mi_ g/mi g/mi MPG
Baseline 0.02 | 0.25 | 0.20 | 0.53 2.2 0.4 | 23.4
0 PH*, 150°F 0.01 | 0.20 | 0.15 | 0.42 2.3 0.5 | 22.1
10 PH, 150°F baked 0.18 | 0.14 | 0.38 2.2 0.5 | 22.2
20 PH, 150°F ae 0.19 | 0.15 | 0.40 2.4 0.7 | 21.2
O PH, 200°F ae 0.21 | 0.16 | 0.44 2.6 0.4 | 22.6
10 PH, 200°F ae 0.19 | 0.14 | 0.39 2.3 0.5 | 22.1

* OQ-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 systen. 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.



I.

II.

IIr.

Iv.

VI.

VII.

VIII.

Ix.

xX.

Table of Contents

Summary... . 1... ee ewe ee ee
Introduction ............e0.6.
Description of Heated Injector Technology
Description of Test Vehicle. ......
Test Facilities and Analytical Methods .
Test Procedures ...........4..
Discussion of Test Results .......
A. Testing At 75°F Ambient Conditions .

B. Testing At 55°F Ambient Conditions. .

c. Testing At Lower Than 55°F Ambient Conditions

Future Efforts ..........2.2..
Acknowledgments .............

References ... 2... ee ee ee eee

Page
Number

1

2

10
15
17
17

18



gh, :
2 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY ‘
i ANN ARBOR, MICHIGAN 48105
a pment

eo 4 ead
| FROM: Karl H. Hellman, Chief

; startability and drives bility. _

* xeview according to the policy outlined in your directive of April_

_. OFFICEOF
AIR AND RADIATION

JAN 8 1993”
MEMORANDUM

SUBJECT: ‘Exemption From Peer and Adm

Control Technology and Applications Branch —

TO: ‘Charles L. Gray, Jr., Director
Emission Control Technology Division

at

The attached report entitled "Evaluation of Resistively Heated
Fuel Injection Technology to Reduce Cold S Emissions and Assist_
Starting/Driveaway of a Methanol-Fueled Ve le," EPA/AA/CTAB/92-
02, provides results from a program to ev: ate a set of heated_
fuel injectors on an Mi00-fueled vehicle in an attempt to lower

cold start emissions of unburned. fuel and_co and to improve cold

ae ee eee Cee ee ee
Since this, report is only concerned with the presentation of

data and its analysis and does not involve matters.of policy or
regulations, your concurrence is requested to waive administrative

bs

22, 1982. ,

Gray, /S7~ Director ECTD



-10-

Table 2 is a summary of the FTP composite emission rates during
testing at 75°F ambient temperature conditions. All emission
levels are presented in grams per mile except for formaldehyde,
which is given in milligrams per mile. A summary of fuel economy
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 CH30H co NOx HCHO
Configuration g/mi g/mi g/mi g/mi__g/mi_g/mi__mg/mi MPG

Baseline
10 PH*, 150°F
10 PH, 200°F

* 10-second preheat period.

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 1
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 1 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. s 55°F Ambient Cond ons

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]



-13-

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

Table 3

Resistively Heated Fuel Injector Evaluation
Test Results °F Ambien: ‘emperature

NMHC OMHCE THC CH30H CO Nox

Configuration g g g g g g MPG
Baseline 0.25 | 3.74

O PH*, 150°F 0.16 | 2.80 | 2.16 | 5.89 | 22.2 2.6

10 PH, 150°F 0.15 | 2.56 | 1.98 | 5.36 | 20.0 2.2

20 PH, 150°F 0.14 | 2.73 | 2.11 | 5.73 | 21.1 3.6

O PH, 200°F 0.18 | 3.06 | 2.36 | 6.42 | 22.9 2.2

10 PH, 200°F 0.16 | 2.70 | 2.08 | 5.66 | 21.6 2.7

* O-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.