EPA/AA/CTAB/87-09
Technical Report
Evaluation of Toyota LCS-M Carina: Phase II
by
Gregory K. Piotrowski
December 1987
NOTICE
Technical Reports do not necessarily represent final EPA
decisions or positions. They are intended to present technical
analysis of issues using data which are currently available.
The purpose in the release of such reports is to facilitate the
exchange of technical information and to inform the public of
technical developments which may form the basis for a final EPA
decision, position or regulatory action.
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Mobile Sources
Emission Control Technology Division
Control Technology and Applications Branch
2565 Plymouth Road
Ann Arbor, Michigan 48105
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Table of Contents
Page
Number
I. Summary 1
II. Introduction 3
III. Vehicle Description 4
IV. Emission Analysis - Methods 5
V. Program Design/Discussion of Test Results 5
A. Improved M100 Best Driveability Calibration . . 5
B. Two-Catalyst System 6
C. Testing At Increased Inertia Weight 11
D. Use of Higher Aspect Ratio Tires. ....... 13
E. Cold Start/Emissions Testing 13
F. Baseline Testing 18
G. Air/Fuel Ratio Analysis 25
VI. Conclusions 26
VII. Acknowledgments 35
VIII.References 36
APPENDIX A - Description of Toyota LCS-M Test Vehicle . . A-l
APPENDIX B - Calculation of HC, Methanol and HCHO .... B-l
APPENDIX C - NTK Micro Oxivision Air/Fuel Ratio Meter . . C-l
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I. Summary
Initial testing of the Toyota Lean Combustion (Methanol)
Carina loaned to the U.S. EPA by the Toyota Motor Corporation
involved ]the determination and comparison of fuel economy and
pollutant emission profiles of the vehicle when operated on
M100 and M85 methanol fuels. The results from this "Phase I"
testing were summarized in SAE Paper 871090, "Fuel Economy and
Emissions of a Toyota T-LCS-M Methanol Prototype Vehicle."
Testing subsequent to Phase I involved a number of short
programs designed to further define the capabilities of this
methanol lean burn system with regard to pollutant emissions
and fuel economy. This testing was conducted using M100 neat
methanol exclusively, and i.= referred to as "Phase II"
testing. A summary of the results from these separate tests is
presented below.
1. An improved version of the M100 best driveability
calibration was tested and the results compared with those from
testing with the PROM originally supplied with the vehicle.
Toyota describes the improved best driveability calibration as
8 percent leaner at idle than the original best driveability
calibration. NOx and CO emission levels over the FTP and HFET
cycles rose when the improved calibration was used. Aldehydes
and hydrocarbons remained at similar emisJLsori levels regardless
of calibration, however. (NOx, CO, arid formaldehyde were
emitted at rates of 1.25 and .93 grams per mile and 12.1
milligrams per mile respectively over the FTP with the improved
calibration.) Composite gasoline eguivalent fuel economy was
39.4 MPG for both calibrations.
2. The Carina was tested with an underfloor converter
in -addition to its original close-coupled manifold converter.
Substantial increases in emission level efficiencies over
manifold catalyst-only testing were obtained for HC, CO, and
aldehydes over the FTP cycle. The two-catalyst system emitted
only 5 milligrams per mile of formaldehyde over the FTP, but
NOx emissions increased to 1.45 grams per mile over the same
cycle. Gasoline equivalent composite fuel economy was 38.8 MPG
with the two-catalyst system.
3. The Carina was tested over FTP/HFET cycles at an
inertia weight of 2625 Ibs, up from 2250 Ibs inertia weight
tested at previously. The additional weight was added to
simulate operation of heavier vehicles equipped with engines of
similar horsepower rating. CO levels over the FTP increased to
1.26 grams per mile, up from the .93 grams per mile measured at
2250 Ibs test weight. Little change in other emission levels
over the FTP or HFET cycle resulted from the additional test
weight. City and highway fuel economy were reduced by .3 and
.7 MPG respectively due to the increased weight.
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4. The original equipment 165SR13 tires on the front
drive wheels were replaced with higher aspect ratio 175/80R13
tires. The use of higher aspect ratio tires than those present
on the vehicle as original equipment simulates the use of a
larger chassis vehicle and increases the demand placed on the
engine at': constant speed.
Efficiencies decreased by 16 to 50 percent in each
emissions category through the use of the higher tires. City
fuel economy was also penalized approximately 5 percent for a
city MPG of 16.2 through the use of the higher tires.
5. The vehicle was soaked and tested in the cold room
to determine: a) the lowest temperature at which the vehicle
would start and run on M100 fuel, and b) the emissions and fuel
economy profiles of this vehicle at lower than 75°F conditions.
The lowest temperature at which the Carina would start and
run reliably was 55°F. Emissions of carbon-containing
pollutants generally increased as soak temperature decreased;
emissions measured as HC increased from .09 to .19 grams per
mile as temperature was decreased from 60° to 55°F, for
example. Average NOx emissions, however, decreased over this
same temperature range, from 1.25 to 1.18 grams per mile. Fuel
economy gradually decreased with decreasing temperature.
Average city-MPG decreased to 16.34 MPG at 55°F from 16.79 MPG
at 75°F.
6. The close-coupled manifold catalyst was removed and
a non-catalyzed substrate substituted in its place to
approximate engine-out, or baseline emissions. Three
electronically controlled air/fuel ratio calibrations were
utilized in this testing: a) a calibration optimized for
driveability, b) a calibration similar to the first, yet 8
percent leaner at idle according to Toyota, and c) a
calibration for operation at the maximum lean limit.
HC baseline levels from the Carina ranged from 7.2 to 7.7
grams per mile over the FTP; CO was emitted at a rate of 5.4 to
5.9 grams per mile over the same cycle. Average formaldehyde
levels over the FTP varied from 312 milligrams per mile with
the improved best driveability calibration to 573.1 milligrams
per mile with the original best driveability calibration. The
lowest HC, CO and formaldehyde levels over the FTP were emitted
when the improved best driveability PROM was utilized. Higher
levels of NOx, over those from the original best driveability
and maximum lean limit calibrations, however were emitted when
the improved best driveability calibration was used. Gasoline
equivalent composite MPG was highest, 40.2 MPG, with the
maximum lean limit calibration.
7. An air/fuel ratio measuring system, described in
Appendix C was used to characterize the lean operating
conditions of the Carina over several steady-state cycles.
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Three separate air/fuel ratio calibrations were utilized, and
pollutant emissions were also measured. Actual dynamometer
horsepower of 8.0 and vehicle inertia test weight of 2250 Ibs
were used for this testing. The dummy catalyst substrate was
used in place of the platinum/rhodium manifold close-coupled
catalyst lin order to provide an estimate of uncatalyzed
engine-out emissions.
The air/fuel ratio measuring technique employed did not
indicate that the improved best driveability PROM was 8 percent
leaner at idle than the original best driveability PROM.
Values of lambda (actual air/fuel ratio divided by
stoichiometric air/fuel ratio) from both best driveability
calibratins were similar over idle cycle testing. The best
driveability calibrations ran at lambda values of 1.0 at idle,
while the maximum lean limit PROM ran leaner, at approximately
a lambda value of 1.14.
The two best driveability calibrations operated at lambda
values of approximately 1.3 over the 10, 20, 30, 40 and 50 MPH
steady-state cycles, which equates to an M100 air/fuel ratio of
approximately 8.4 to 1. The maximum lean limit calibration
operated at very near a lambda of 1.4 for these same cycles,
which equates to an M100 air/fuel ratio of approximately 9.0 to
1. HC, NOx, and formaldehyde levels at idle were similar among
the three PROMs; approximately 0.6 and 0.04 grams per minute
and 50 to 80 milligrams per minute, respectively. CO emissions
with the maximum lean limit PROM, 0.41 grams per minute, were
less than 30 percent of the emission levels from the best
driveability PROMs, however.
NOx levels at 10 MPH were 1.22 grams per mile with the
lean limit PROM, approximately 30 percent below levels from the
other PROMs. HC and CO levels were similar over all three
calibrations. Aldehyde emissions approached an average 600
milligrams per mile with the improved best driveability
calibration; the other two calibrations emitted at roughly
twice this level. This difference in aldehyde levels, due
solely to the air/fuel ratio calibration dissimilarities, is
difficult to explain, particularly the difference between the
two best driveability calibrations. Further analysis of the
steady-state data is currently underway.
Average aldehyde values did not exceed 650 milligrams per
mile for any calibration over the 20, 30, 40, and 50 MPH
cycles, considerably lower levels than the emission rates
reported at 10 MPH conditions. CO emissions did not exceed an
average 2.5 grams per mile with any calibration over these
cycles, and average CO emission rates generally decreased with
increasing speed for each calibration. Emissions measured as
HC also generally decreased as speed increased with each
calibration over these cycles.
II. Introduction
The Toyota Lean Combustion System (T-LCS) was described in
a paper appearing in the Japanese Society of Automotive
Engineering Review for July 1984.[1] This lean burn system
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made use of three particular technologies[2] to achieve
improvements in fuel economy as well as comply with emission
requirements under the Japanese 10-mode cycle:
A. ..A lean mixture sensor[3] was used in place of an
oxygen sensor to control air/fuel ratio in the lean mixture
range;
B. A swirl control valve[4] upstream of the intake
valve was adopted to improve combustion by limiting torque
fluctuation at increased air/fuel ratios; and
C. Sequential fuel injection with optimized injection
timing was used to complement the operation of the swirl
control valve.
The Toyota Lean Combustion System Methanol (T-LCS-M) is
similar to the T-LCS, but has been modified to maximize fuel
economy and driving performance while minimizing pollutant
emissions through the use of methanol fuel. SAE Paper
860247[5] described the development of the T-LCS-M system.
EPA became interested in this system because of its use of
fuel methanol and Toyota provided EPA a T-LCS-M system in a
Carina chassis. The Toyota Carina is a right-hand-drive
vehicle sold in Japan. The vehicle provided to EPA was capable
of operation on both M85 and M100 fuels by changing the onboard
electronic control unit (PROM, for programmable read-only
memory) to a system compatible with the fuel.
Initial testing of this vehicle at the EPA Motor Vehicle
Emissions Laboratory involved the use of both M85 and M100
methanol fuels. This "Phase I" testing involved the
determination and comparison of fuel economy and pollutant
emission profiles of the vehicle when operated on each of these
fuels. A summary of this testing was published in SAE Paper
871090.[6]
Testing subsequent to Phase I involved a number of
separate issues concerned with various aspects of the T-LCS-M
system. This testing was conducted using MlOO neat methanol
exclusively, and is referred to as "Phase II" testing. Some of
these issues have been reported on in earlier
memoranda.[7,8,9,10] A summary of these separate issues has
been compiled, however, and is reported here.
III. Vehicle Description
The test vehicle is a 1986 Toyota Carina, a vehicle sold
in Japan but currently not exported to the United States. The
power plant is 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. Modifications to the fuel system included the
substitution of parts resistant to methanol corrosion.
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The car can be operated on M100 (neat methanol) as well as
M85 methanol/gasoline blend. Fuel changeover is accomplished
by draining and flushing the fuel system and changing the PROM
to a unit compatible with the desired fuel. The testing
reported |On here was conducted using M100 neat methanol
exclusively, however. Details and specifications for the
vehicle are given in Appendix A.
IV. Emission Analysis - Methods
Exhaust hydrocarbon emissions were measured by flame
ionization detection (FID) using a Beckman Model 400 calibrated
with propane; no attempt was made to adjust for FID response to
methanol. No corrections were made for the difference in
hydrocarbon composition due to the use of methanol rather than
unleaded gasoline. An alternate method which has been proposed
[11] requires the reporting of methanol and organic material
hydrocarbon equivalents (OMHCE). An explanation of the
methanol data presented in this paper is given in Appendix B.
NOx emissions were measured by the chemiluminescent
technique utilizing a Beckman Model 951A NOx analyzer. CO was
measured using a Bendix Model 8501-5CA infrared CO analyzer.
Exhaust formaldehyde was measured using a dinitrophenyl-
hydrazine (DNPH) technique.[12] Exhaust carbonyls including
formaldehyde are bubbled through DNPH solution or drawn through
DNPH-coated cartridges forming hydrazone derivatives. These
derivatives are separated from the remaining unreacted DNPH by
high ' performance liquid chromatography (HPLC). A
spectrophotometer in the chromatograph effluent stream drives
an integrator which determines formaldehyde derivative
concentration.
V. - Progam Design/Discussion of Test Results
A. Improved M100 Best Driveability Calibration
Toyota supplied EPA with two M100 electronic calibrations
for the LCS-M Carina different that the calibration reported on
in SAE Paper 871090.[6] The M100 electronic control unit
mentioned in SAE Paper 871090 was calibrated for best
driveability conditions, and is referred to as the "original"
M100 best driveability PROM. The "improved" M100 best
driveability calibration reported on here operated at an 8
percent leaner setting at idle than the "original" best
driveability calibration; no other changes were made, however.
The other recently provided M100 calibration, set to operate at
maximum lean limit conditions, is referred to later in this
report.
The Carina was tested several times over the Federal test
procedure (FTP) and highway fuel economy test (HFET) cycles
utilizing the original best driveability calibration. The PROM
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was then replaced with the improved calibration and the car was
tested over the same cycles. The close-coupled manifold
converter that the vehicle was originally equipped with was
kept in the exhaust stream during this testing. Emissions and
fuel economy test results from the improved calibration are
presented^ in Tables 1, 2, and 3; results from the original
calibration testing are also presented for comparison.
Average CO and NOx emissions increased 21 percent and 29
percent respectively over the FTP cycle when the improved
calibration was used. No out-of-the-ordinary driving problems
were noted during this testing, however. Aldehydes and
emissions measured as hydrocarbons remained at similar levels
over both calibrations. Emissions of aldehydes and NOx
increased to 11.4 mg/mi and 0.97 g/mi over the HFET cycle, up
from 8.5 mg/mi and 0.73 g/mi respectively with the original
best driveability PROM. While emissions measured as HC and CO
also increased with the leaner improved PROM, the reference
levels obtained with the original best driveability PROM were
very low.
Composite fuel economy was not appreciably aided by the
leaner calibration. While a small gain in fuel economy under
city driving conditions was noticed with the improved PROM, the
original calibration had a slightly higher MPG under highway
conditions. The result was a similar composite MPG and hence a
similar gasoline equivalent MPG of 39.4 for both calibrations.
B. Two-Catalyst System
The LCS-M Carina arrived at the EPA Motor Vehicle
Emissions Laboratory equipped with a close-coupled manifold
catalytic converter. The exhaust system was modified to
accept an underfloor converter in addition to the manifold
catalyst. The underfloor converter was the "black box"
converter from Engelhard Industries that was tested as part of
the EPA low mileage methanol catalyst test program. This
combination of manifold and underfloor converters tested
simultaneously is referred to here as the "two-catalyst" system.
The "black box" converter is so named because its maker,
Engelhard Industries, has not yet disclosed the catalytic
formulation to protect patent rights. Engelhard
representatives have stated, however, that this formulation may
be particularly effective in an oxidation catalyst mode.
Testing this configuration on a lean burn vehicle, therefore,
would seem to be particularly appropriate.
The black box was installed in the exhaust stream
approximately 1 foot downstream from the close-coupled
manifold converter. The improved M100 best driveability PROM
was used in this testing. The car was tested three times over
FTP/HFET cycles. FTP results are presented in Table 4,
together with recent results from vehicle testing with only a
manifold catalyst. Efficiencies over manifold-catalyst-only
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Table 1
Improved Ml00 Best Driveability PROM
Test
Number
1
2
3
4
Average
Test
Averages
Average
Efficiency
Percent
HC
q/mi
.06
.08
.08
.08
.08
HC
q/mi
.07
Em is
CO
q/mi
.64
1.14
1.01
.91
.93
Original
CO
g/mi
FTP
C02
q/mi g
240.4
238.7
242.4
240.2
Cycle
NOx
•/mi
1.03
1.19
1.33
1.46
Aide
mg/mi
11.5
13.1
13.3
10.4
HC*
g/mi
.007
.010
.010
.009
CH30H* OMHCE*
g/mi g/mi
.17 .09
.22 .11
.22 .11
.20 .10
240.4 1.25 12.1 .009 .20 .10
Ml 00 Best Driveability PROM
FTP
C02
g/mi g
.77 242.8
sions Efficiency
Over The Orig
HC CO
(14
.3) (20.
FTP
NOx
7) (28.
Cycle
NOx Aide HC*
/mi mg/mi g/mi
.97 12.4 .009
of Improved Calibr
inal Calibration
Cycle
Aide
9) (
2.4)
HC*
<-,
CH30H* OMHCE*
g/mi q/mi
.20 .10
at ion
CH30H* OMHCE*
<-> <->
* Calculated values per proposed rulemaking.
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-8-
Table 2
Improved MlQO Best Driveability PROM
HFET Cycle
Test
Number
1
2
3
4
Average
HC
g/mi
.005
.005
.006
.005
.005
CO
q/mi
.04
.04
.08
.04
.05
C02
g/mi
167.4
168.6
169.5
171.7
169.3
NOx
g/mi
.89
.87
1.06
1.06
.97
Aide
mg/mi
10.2
11.6
11.7
12.2
11.4
HC*
g/mi
.001
.001
.001
.001
.001
CH30H*
g/mi
.01
.01
.02
.01
.01
OMHCE*
g/mi
.01
.01
.01
.01
.01
Original M100 Best Driveability PROM
HFET Cycle
Test HC
Averages g/mi
Average
.004
CO
g/mi
.02
HC* CH30H* OMHCE*
I/mi g/mi g/mi
167.8
.73
8.5
.001
.01
.01
Emissions Efficiency of Improved Calibration
Over the Original Calibration
HFET Cycle
CO
NOx
Aide HC* CH30H* OMHCE*
Efficiency HC
Percent (25.0) (150.) (32.9) (34.1) ( —) ( —) ( —)
* Calculated values per proposed rulemaking.
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Table 3
Summary of Fuel Economy Test Results
Original/Improved M100 Calibrations
Testing City Highway Composite Gasoline Equiv,
Configuration MPG MPG MPG Composite MPG
Improved M100 PROM 17.0 24.3 19.6 39.4
Manifold Catalyst
Original M100 PROM 16.8 24.5 19.6 39.4
Manifold Catalyst
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Table 4
Two-Catalyst System Testing
FTP Cycle
Improved Ml 00 Best
Test
Number
1
2
3
Average
HC
q/mi
.06
.06
.06
.06
CO
g/mi
.61
.64
.82
.69
C02
q/mi
246.8
243.1
243.2
244.4
Driveability Calibration
NOx
q/mi
1.47
1.46
1.43
1.45
Aide
mq/mi
5.1
5.6
4.9
5.2
HC*
g/mi
.008
.007
.008
.008
CH30H*
q/mi
.18
.16
.18
.17
OMHCE*
g/mi
.09
.08
.09
.09
Recent FTP Results, Manifold Catalyst Only
Test HC
Averages q/mi
Average
.08
CO
q/mi
.93
Aide HC* CH3OH* OMHCE*
mq/mi g/mi g/mi g/mi
240.4 1.25
12.1
.009
.20
.10
Efficiency of Two-Catalyst System
Over Manifold Catalyst Only
Efficiency HC CO NOx Aide
Percent 25.0 25.8 (16.0) 57.4 11.1
HC* CH30H* OMHCE*
15.0
10.0
Calculated values per proposed rulemaking.
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test ing have been calculated and are also included. HFET
results are presented in similar format in Table 5. Fuel
economy results for this testing are presented in Table 6.
Substantial increases in emission level efficiencies over
manifold Catalyst-only testing were obtained for HC, CO, and
aldehydes*over the FTP cycle. Particularly notable was the 57
percent decrease in aldehyde levels, from 12 to roughly 5
milligrams per mile. Though not presented here, an analysis of
bag data revealed that all of the aldehydes measured here were
collected in Bag 1—no aldehydes were detected>in Bags 2 or 3.
NOx levels, however, rose to an average 1.45 grams per mile, a
16 percent increase over the manifold-catalyst-only comparison
level.
HFET results are presented in Table 5, together with
results from manifold-catalyst-only testing for comparison.
The overall trend is for emission levels to follow in
direction, though of course not in magnitude, those from FTP
testing.
Substantial increases in HC, CO and aldehyde conversion
efficiency were attained through use of the'black box converter
over the HFET cycle. HC and CO levels from manifold-catalyst-
only testing were very low, however, so the decrease in mass of
emissions was not great. Aldehyde levels decreased from 11.4
to 0.0 milligrams per mile; this was a significant decrease.
NOx levels however increased 14 percent over those from testing
with the manifold-catalyst-only.
Fuel economy decreased over both city and highway cycle
through the use of the two catalyst system compared to th
close-coupled manifold catalyst system; the decrease i
efficiency was not extreme, however. The decrease in city anc
highway M100 MPG was 0.3 and 0.4 respectively for a gasoline
equivalent composite MPG of 38.8 with the dual-catalyst system.
C. Testing At Increased Inertia Weight
The LCS-M Carina had been previously evaluated at a test
weight of 2250 Ibs and at an' actual dynamometer horsepower of
8.0. Toyota claimed that the engine horsepower of the
1.6-liter LCS-M engine is approximately 80 hp. The 1984 Test
Car List was examined to determine average inertia weight and
dynamometer horsepower ratings of vehicle systems with similar
engine horsepower ratings. Considered cars also had to be
comparably equipped in terms of transmissions and emission
control equipment. The selected cars included Ford's Escort,
GM 2000 Sunbird, Toyota's Camry, the Mazda 626, VW Jetta, and
the Mitsubishi Cordia. A test weight of 2625 Ibs at 8.0 actual
dynamometer horsepower was selected as representative.
A 60/40 weight loading between front and rear wheels for
this front-wheel-drive car was assumed, and the wall between
the engine and front seat compartment was loaded with 233 Ibs
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Average
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Table 5
Two-Catalyst System Testing
HFET Cycle
Improved
Test
Number
1
2
3
Average
Test
Average
HC
q/mi
.003
.004
.003
CO
g/mi
0.00
0.01
0.00
M100
C02
g/mi
177.
170.
169.
Best Driveability Calibration
0
1
9
NOx
g/mi
1.23
1.04
1.05
Aide
mg/mi
0.0
0.0
0.0
.003 0.00 172.3 1.11 0.0
Recent HFET Results, Manifold
HC
g/mi
CO
g/mi
C02
g/mi
NOx
g/mi
HC* . CH30H*
g/mi g/mi
.000
.001
.000
.000
Catalyst
.008
.013
.008
.008
Only
Aide HC* CH30H*
mg/mi g/mi g/mi
OMHCE*
g/mi
.004
.006
.004
.004
OMHCE*
g/mi
.005
.05
169.3
.97
11.4
.001
.01
.01
Efficiency of Two-Catalyst System
Over Manifold Catalyst Only
Efficiency HC
Percent 40.0
CO
NOx
Aide
HC* CH30H*
100.0 (14.4) 100.0 100.0 20.0
OMHCE*
60.0
Calculated values per proposed rulemaking.
Table 6
Summary of Fuel Economy Test Results
Manifold Catalyst/Two-Catalyst System
Testing
Configuration
City Highway Composite Gasoline Equiv,
MPG MPG MPG Composite MPG
Manifold Catalyst Only 17.0 24.3
Dual Catalyst System 16.7 23.9
19.6
19.3
39.4
38.8
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of sandbags. This was the most practical way of loading the
vehicle. The improved M100 best driveability calibration was
used, and the car tested twice over FTP/HFET cycles. Emission
test results are given in Tables 7 and 8, and fuel economy
results are summarized in Table 9.
r
Little change in emission levels resulted from the
additional loading of the vehicle and testing over the FTP
cycle. NOx, aldehyde and HC levels were relatively unaffected
by this testing. CO levels over the FTP, however, increased to
1.26 grams per mile, above the 0.93 grams per mile level at
2250 Ibs test weight. The only notable difference in HFET test
results was the decrease to 0.70 grams per mile NOx at 2625
Ibs. The difference between the two individual NOx test
results, 0.40 grams per mile, is high when compared to the
average level of 0.70 grams per mile.
A degradation in fuel economy occurred with testing at the
increased inertia weight. City and highway MPG were reduced by
0.3 and 0.7 MPG respectively due to the increased weight.
Gasoline composite MPG was 38.6 at 2625 Ibs. test weight.
D. Use of Higher Aspect Ratio Tires
The use of higher aspect ratio tires than those present on
the vehicle as original equipment simulates the use of a larger
chassis vehicle and increases the demand placed on the engine
at constant speed. A degradation in emissions performance and
fuel economy may be expected from this increased demand on
engine output.
The original equipment tires (165SR13) on the front-drive
wheels were replaced with the highest aspect ratio 13-inch tire
that we could fit on the wheels (185/80R13). Larger tires
would have interfered with the suspension struts which extended
out over the front wheels. The vehicle was then tested over
the FTP cycle. This testing was accomplished at 2250 Ibs
inertia weight, 8.0 actual dynamometer horsepower, and utilized
the M100 improved best driveability calibration and
close-coupled manifold converter. Test results are presented
in Tables 10 and 11.
Emission levels increased in each category over those
obtained with the lower aspect ratio tires. Emission
efficiencies decreased by 16 to 50 percent in each emission
category. Fuel economy over city driving conditions was also
penalized, the penalty amounting to 0.8 MPG or roughly 5
percent from the reference figure presented in Table 11.
E. Cold Start/Emissions Testing
The Carina was soaked overnight in the cold room at
successively lower temperatures, each soak followed by a cold
start and test over the FTP cycle. The purpose of this testing
was twofold: 1) to determine the lowest temperature at which
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Table 7
Testing At 2625 Lbs. Inertia Weight
FTP Cycle
Improved MlOO Best Driveability Calibration
Test
Number
l
2
Average
HC
g/mi
.06
.07
.07
CO
g/mi
1.30
1.22
1.26
C02
g/mi
244.9
244.0
244.5
NOx
g/mi
1.19
1.27
1.23
Aide
mg/mi
12.4
11.8
12.1
HC*
g/mi
.008
.009
.009
CH30H*
g/mi
.18
.21
.20
OMHCE*
g/mi
.09
. 11
. 10
Testing at 2250 Lbs. Inertia Weight
FTP Cycle
Improved MlOO Best Driveability Calibration
.Test HC
Averages g/mi
CO
'mi
Aide HC* CH30H* OMHCE*
mg/mi g/mi g/mi g/mi
Average
.08
.93
240.4
1.25 12.1 .009
.20
.10
Emissions Efficiency At 2625 Lbs. Test Weight
Compared With 2550 Lbs. Test Weight
Efficiency HC CO
Percent 12.5 (35.5) 1.6
NOx Aide HC* CH3OH* OMHCE*
Calculated values per proposed rulemaking.
-------
-15-
Table 8
Testing at 2625 Lbs. Inertia Weight
HFET Cycle
Improved Ml 00 Best Driveability
Test
Number
1
2
Average
HC CO
g/mi g/mi
.006 .05
.005 .07
.005 .06
Testing
C02
g/mi
175.7
172.3
174.0
At 2250
NOx Aide
g/mi mg/mi
.50 14.9
.90 12.6
.70 13.8
Lbs. Inertia
Calibration
HC* CH30H*
g/mi g/mi
.001 .01
.001 .01
.001 .01
Weight
OMHCE*
g/mi
.01
.01
.01
HFET Cycle
Improved M100 Best Driveabilityi
Test
Averages
Average
Eff icency
Percent
HC CO
g/mi g/mi
C02
g/mi
NOx Aide
g/mi mg/mi
.005 .05 169.3 .97 11.4
Emissions Efficiency At 2625 Lbs.
Compared With 2250 Lbs. Test
HC CO
(20.0)
NOx
20.6
Aide HC*
(21.0) —
Calibration
HC* CH3OH*
g/mi g/mi
.001 .01
Test Weight
Weight
CH30H* OMHCE*
— —
OMHCE*
g/mi
.01
Calculated values per proposed rulemaking.
-------
-16-
Table 9
Summary of Fuel Economy Test Results
2625 Lbs Test Weight/2250 Lbs Test Weight
Testing City Highway Composite Gasoline Equiv,
Configuration MPG MPG MPG Composite MPG
2250 pounds test weight 17.0 24.3 19.6; 39.4
2625 pounds test weight 16.7 23.6 19.2 38.6
-------
Test
Number
1
2
Average
Test
Average
-17-
Table 10
Testing With Higher Aspect Ratio Tires
FTP Cycle, M100 Improved Best Driveability
HC
g/mi
.12
.11
.12
CO
q/mi
1.21
1.09
1.15
C02
q/mi
253.6
248 . 8
251.2
Recent Test
NOx
q/mi
1.54
' 1.35
1.45
Results
PROM
Aide HC* CH30H*
mq/mi q/mi q/mi
15.1 .014
14.8 .012
15.0 .013
, OEM Tires
FTP Cycle, MlOO Improved Best Driveability
HC
q/mi
CO
q/mi
C02
q/mi
NOx
q/mi
.31
.29
.30
PROM
Aide HC* CH30H*
mq/mi q/mi
q/mi
OMHCE*
q/mi
.15
.14
.15
OMHCE*
q/mi
.08
.93
240.4 1.25
12.1 .009
.20
.10
Emissions Efficiency, Higher Aspect
Ratio Tires Over OEM Tires
Efficiency HC CO NOx Aide HC* CH3OH* OMHCE*
Percent (50.0) (23.7) (16.0) (24.0) (44.4) (50.0) (50.0)
Calculated values per proposed rulemaking.
Table 11
Summary of Fuel Economy Test Results
Higher Aspect Ratio Tires Versus OEM Tires
Testing Configuration
OEM tires
Higher aspect ratio tires
City MPG
17.0
16.2
-------
-18-
the vehicle would start and run on M100 fuel; and 2) to
determine the emissions and fuel economy profiles of this
vehicle at lower than 75°F conditions. This testing was
conducted using the original M100 best driveability
calibration. The Carina was not equipped with any special cold
start assist devices for this testing.
The vehicle was started and tested twice at 75°F. As
expected, the vehicle experienced no significant driveability
problems. No problems were experienced at 60°F conditions
either. The car would not start at 50°F, however. Five-second
cranking periods were followed by 10-second pause periods for
this start attempt; this crank/pause cycle was repeated seven
times before failure to start was declared. The car was then
started and tested twice at 55°F conditions. An extended
15-second crank was necessary in order to start the engine at
55°F conditions. Emission results are presented in Table 12,
while fuel economy results are given in Table 13.
Emissions of carbon-containing pollutants generally
increased as soak temperatures decreased; emissions measured as
HC increased from 0.09 to 0.19 grams per mile as temperature
was decreased from 60° to 55°F, for example. Average NOx
emissions, however, decreased over this same temperature range,
from 1.25 to 1.18 grams per mile. Fuel economy gradually
decreased with decreasing temperature. Average city MPG
decreased to 16.34 MPG at 55°F from 16.79 MPG at 75°F.
F. Baseline Testing
In addition to the two PROMs calibrated for best
driveability which were mentioned earlier in this paper, a
third M100 PROM was supplied to EPA by Toyota. This PROM was
calibrated for maximum lean operation, and is referred to here
as the M100 maximum lean limit PROM. A dummy manifold catalyst
substrate was also supplied to EPA, and this substrate replaced
the original manifold catalyst for an effort to measure
engine-out, or baseline emissions from the vehicle. Baseline
as defined in this testing on the Carina includes the dummy
substrate in the vehicle exhaust, rather than a "straight pipe"
replacing the converter arrangement.
The Carina was tested several times over the FTP/HFET test
cycles, utilizing each of the M100 PROM's. The dummy catalyst
was used in place of the platinum/rhodium manifold catalyst
during this testing. Emissions data is provided in Tables 14,
15, and 16 while a fuel economy summary is presented in Table
17.
Tests of an MIOO-fueled Volkswagen Rabbit equipped with a
1.6-liter engine indicated baseline HC emission levels of 0.96
grams per mile over the FTP. [133 This Volkswagen vehicle
utilized a straight pipe rather than a dummy catalyst substrate
for baseline testing, however. HC levels from the Carina
presented here varied from 7.2 to 7.7 grams per mile. CO from
this Volkswagen engine was measured at 6.54 grams per mile over
-------
-19-
Table 12
Cold Room Testing
Oriqinal M100 Best Driveability
Test
Number
1
2
Average
Test
Number
l
2
Average
Test
Number
1
2
Average
HC
g/mi
.08
.07
.08
HC
g/mi
.08
.09
.09
HC
g/mi
.22
.15
.19
CO
g/mi
.79
.92
.86
CO
g/mi
.93
.96
.95
CO
g/mi
1.25
1.11
1.18
75
C02
g/mi
232.2
255.1
243.7
60
C02
g/mi
243.5
246.3
244.9
55
CO2
g/mi
250.2
248.0
249.1
°F Soak
NOx
g/mi
1.01
1.20
1.11
°F Soak
NOx
g/mi
1.22
1.28
1.25
°F Soak
NOx
g/mi
1.18
1.17
1.18
Calibration — FTP Cycle
Aide
mg/mi
12.3
9.6
11.0
Aide
mg/mi
9.2
N/A
9.2
Aide
mg/mi
19.7
11.3
15.5
HC*.
g/mi
.010
.009
.010
HC*
g/mi
.009
.011
.010
HC*
g/mi
.020
.020
.020
CH30H*
g/mi
.22
.20
.21
CH3OH*
g/mi
.22
.25
.24
CH30H*
g/mi
.61
.41
.51
OMHCE*
g/mi
. 11
. 10
. 11
OMHCE*
g/mi
.11
.12
.12
OMHCE*
g/mi
.30
.20
.25
* Calculated per proposed rulemaking.
N/A signifies test results not available.
-------
-20-
Table 13
Summary of Fuel Economy Test Results
Testing
Conf iquration
75°F Soak
60°F Soak
55°F Soak
Cold Room Testing
City MPG
16.79
16.65
16.34
Gasoline
Ecru iva lent MPG
33.76
33.47
32.86
-------
-21-
Table 14
Baseline Testing—FTP Cycle
Original M100 Best Dciveability Calibration
Test
Number
1
2
3
Average
9.05
7
7
09
01
7.72
CO
5.11
6.46
6.12
208.2
204.7
203.0
5.90 205.3
NOx Aide HC* CH30H* OMHCE*
'mi mq/mi q/mi q/mi q/mi
1.38 608.8 1.065
1.63 561.9 .834
1.52 548.7 .825
1.51 573.1 .908
24.60 12.00
19.26 9.43
19.05 9.33
20.97 10.25
Improved M100 Best Driveability Calibration
Test
Number
1
2
3
Average
HC
q/mi
8.21
6.87
6.54
7.21
CO
q/mi
5.53
4.74
5.83
5.37
C02
q/mi
203.2
206.2
209.7
206.4
NOx
q/mi
1.51
1.52
1.84
1.62
Aide
mq/mi
473.7
232.7
230.8
312.4
HC*
q/mi
.966
.808
.770
.848
CH3OH*
q/mi
22.31
18.66
17.78
19.58
OMHCE*
q/mi
10.85
9.00
8.58
9.48
M100 Maximum Lean Limit Calibration
Test
Number
1
2
3
4
Average
HC
q/mi
8.52
7.54
6. 17
7.04
7.32
CO
q/mi
5.70
5.42
5.28
5.36
5.44
C02
q/mi
198.3
197.8
204.8
198.4
199.8
NOx
q/mi
1. 14
1.01
1.02
0.87
1.01
Aide
mq/mi
500.0
454.1
621,1
597.0
543.1
HC*
q/mi
1.002
.887
.726
.828
.861
CH30H*
q/mi
23.15
20.49
16.77
19.12
19.88
OMHCE*
q/mi
11.26
9.97
8.28
9.38
9.72
Calculated values per proposed rulemaking.
-------
-22-
Table 15
Baseline Testing—HFET Cycle
Original M1QO Best Driveability Calibration
Test
Number
1
2
Average
HC
q/mi
CO
1.91
2.06
C02
151.1
149.2
1.21
0.76
155.6
196.7
1.99 150.2 0.99 176.2
HC* CH30H* OMHCE*
q/mi q/mi
587 13.55 6.53
330 7.62 3.72
459 10.59 5.13
Improved M100 Best Driveability Calibration
Test
Number
1
2
3
4
Average
2.98
CO
q/mi
2.10
1.95
1.97
C02
q/mi
152.6
148.9
151.8
NOx
q/mi
1.39
1.05
1.10
Aide
mg/mi
188.0
98.6
94.9
HC*
q/mi
.509
.510
.452
2.01 151.1 1.18 127.2 .490
M100 Maximum Lean Limit Calibration
CO
q/mi
2.09
2. 11
2.05
1.82
2.02
C02
q/mi
149.0
148.0
143.9
150.4
147.8
NOx
q/mi
.52
.51
.50
.57
.53
Aide
mq/mi
286.6
258.5
278.4
229 . 1
263.2
HC*
q/mi
.332
.323
.390
.358
.351
CH30H*
q/mi
11.76
11.78
10.45
11.33
CH30H*
q/mi
7.67
7.47
9.00
8.28
8.11
OMHCE*
q/mi
5.69
5.66
5.02
5.46
OMHCE*
q/mi
3.79
3.68
4.42
4 .04
3.98
-------
-23-
Table 16
Emissions Efficiency of Two-Catalyst
System Over Baseline Emissions
FTP Cycle—Improved Ml00 Best Driveability PROM
Emissions
Efficiency HC CO NOx Aide HC* , CH30H* OMHCE'
Percent 99.2 87.2 10.5 98.3 99.1 99.1 99.1
Emissions Efficiency =... Two-Catalyst
System Over Baseline Emissions
HFET 'Cycle—Improved Ml00 Best Driveabilitv PROM
Emissions
Efficiency HC CO NOx Aide HC* CH30H* OMHCE*
Percent 99.9 100. 5.9 100. 100. 99.9 99.9
-------
-24-
Table 17
Summary of Fuel Economy Test Results
Baseline Testing
Testing City Highway Composite Gasoline Equiv
Configuration MPG MPG MPG Composite MPG
Original best 16.6 24.3 19.4 39.0
driveability calibration
Improved best 16.8 24.0 19.4 39.0
driveability calibration
Maximum lean 17.2 25.0 20.0 40.2
limit calibration
-------
-25-
the FTP; a comparable 5.4 to 5.9 grams per mile was measured
with the Carina. While NOx baseline emission levels were
comparable between these vehicles when the best driveability
Carina PROMS are considered, the Carina maximum lean limit PROM
emitted ,^>nly an average 1.01 grams per mile NOx over the FTP.
This levfel was substantially below the 1.5 to 1.6 grams per
mile NOx measured with the Carina best driveability PROMs.
Formaldehyde emission levels from the Carina were also above
those reported from this Volkswagen vehicle testing. The
Carina original best driveability and maximum lean limit
calibrations emitted formaldehyde emissions of 573 to 543
milligrams per mile over the FTP, respectively. These levels
were more than twice as high as the average 252 milligrams per
mile over the same cycle with the Volkswagen vehicle.
The efficiency of the catalyst system tested on this
vehicle may be better appreciated by a comparison of emissions
from the catalyst-equipped car versus the baseline levels
presented here. Table 16 presents the emissions efficiency of
the two-catalyst configuration referred to earlier in this
report versus baseline levels over each pollutant measured.
All carbon-containing pollutant levels were greatly
reduced by the two-catalyst system; efficiencies over both
cycles exceeded 90 percent, with the exception of CO over the
FTP cycle. NOx efficiencies were very low in comparison to
those of the carbon-containing pollutants, however. The NOx
improvement with the two-catalyst system was a mere 6 percent
over the HFET cycle.
The fuel economy figures presented in Table 17 are similar
to those presented in Tables 3 and 6, manifold catalyst and
two-catalyst equipped testing respectively. A slight trend
toward better fuel economy from the maximum lean limit PROM,
however, is evident from the higher city and highway MPG
figures obtained with this calibration, over the best
driveability PROMs.
G. Air/Fuel Ratio Analysis
A measure of the how lean the vehicle may be operated may
be taken by operating the vehicle at various steady-state modes
and measuring air/fuel ratio requirements over these modes.
The Micro Oxivision air/fuel ratio meter, Model MO-1000, is
described by its manufacturer NGK Spark Plug Co., Ltd., as
being able to perform this analysis quickly over a wide range
of fuels, to include methanol. The testing described below
made use of this meter to characterize air/fuel ratio
requirements over several steady-state conditions with the
Carina. Details of the operation of this meter and the exhaust
gas sensor used are given in Appendix C.
All three M100 calibrations referred to earlier in this
paper were used in this evaluation. The dummy catalyst
substrate was used in place of the platinum/rhodium manifold
close-coupled catalyst in order to provide an estimate of
-------
-26-
uncatalyzed engine-out emissions. The exhaust gas sensor was
mounted in the exhaust pipe approximately 1 foot downstream of
the manifold-mounted dummy catalyst. The vehicle was tested
over idle, 10, 20, 30, 40 and 50 mile per hour steady-state
conditions with the original and improved best driveability
calibrations, as well as the maximum lean limit calibration.
Lambda, i-which is defined as actual air/fuel ratio over
stoichiometric air/fuel ratio, was measured to give an
indication of engine leanness at these various steady-state
conditions. Pollutant emissions were also measured during this
testing. A summary of emissions data and air/fuel data in the
form of lambda is given in Tables 18 through 23.
Toyota has claimed that the improved MlOO best
driveability calibration was 8 percent leaner at idle than the
original best driveability calibration. The data in Table 18
indicate a slightly richer mixture at idle for the improved
PROM, however. The mixture was approximately 10 percent leaner
than best driveability PROM levels at idle when the maximum
lean limit calibration was used. HC, NOx, and formaldehyde
levels at idle were similar among the three PROMs; CO emissions
with the maximum lean limit PROM were less than 30 percent of
the emission levels from the best driveability PROMs.
An average lambda of 1.38 was measured with the maximum
lean limit PROM at 10 MPH steady-state conditions, slightly
leaner than the 1.31 measured with the improved best
driveability calibration. NOx levels at 10 MPH were 1.22 grams
per mile with the lean limit PROM, approximately 30 percent
below levels from the other PROMs. HC and CO levels were
similar over all three calibrations. Aldehyde emissions
approached an average 600 milligrams per mile with the improved
best driveability calibration; the other two calibrations
emitted at roughly twice this level. This difference in
aldehyde levels, due solely to the air/fuel ratio calibration
dissimilarities, is difficult to explain, particularly the
difference between the two best driveability calibrations.
Average lambda values over 20, 30, 40, and 50 MPH testing
cycles exhibit a trend of roughly equivalent values between the
two best driveability calibrations and a leaner value for the
lean limit calibration at each testing cycle. The lean limit
PROM lambda values approached 1.4 while the best driveability
PROMs gave measured lambda values near 1.3 for this testing.
Average aldehyde values did not exceed 650 milligrams per mile
for any calibration over these cycles, considerably lower at
levels than the emission rates reported at 10 MPH conditions.
CO emissions did not exceed an average 2.5 grams per mile with
any calibration over these cycles, and average CO emission
rates generally decreased with increasing speed for each
calibration. Emissions measured as HC also generally decreased
with increasing speed with each calibration over these cycles.
VI. Conclusions
Conclusions from each aspect of Phase II testing are drawn
below.
-------
-27-
Test
Number
1
2
3
Average
Table 18
Idle Cycle Testing
Original M100
HC
g/min
1.00
.31
.46
.59
CO
g/min
1.46
2.25
1.25
1.65
NOX
g/min
.07
.02
.03
.04
Best Driveability PROM
Aide
mg/min
143.1
40.3
49.4
77.6
HC*
g/min
.117
.036
.054
.069
CH30H*
g/min
2.70
.84
1.26
1.60
OMHCE*
g/min
1.35
.42
.62
.80
Lambda
1.10
.94
1.Q6
1.03
Improved Ml00 Best Driveability PROM
Test
Number
1
2
Average
CO NOX Aide HC* CH30H* OMHCE*
T/min g/min mg/min g/min g/min g/min Lambda
,35
.70
,53
Test
Number
l
2
3
4
5
Average
HC
g/min
.40
.46
.37
.55
1.04
.56
CO
g/min
.68
.48
.30
.34
.25
.41
2.49
1.78
2.14
M100
CO
'/min c
.68
.48
.30
.34
.25
.41
.03
.05
.04
32.4
72.6
52.5
Maximum Lean
NOx
?/min
.03
.04
.05
.05
.09
.05
Aide
mg/min
44.7
51.6
60.9
52.3
59.7
53.8
.041
.082
.062
Limit
HC*
g/min
.047
.054
.044
.065
.122
.066
.95
1.90
1.43
PROM
CH30H*
g/min
1.08
1.24
1.02
1.49
2.82
1.53
.47
.94
.71
OMHCE*
g/min
.54
.61
.51
.74
1.37
.75
.96
1.04
1.00
Lambda
1.08
1.08
1.12
1.16
1.26
1.14
Calculated per proposed rulemaking.
-------
-28-
Table 19
10 MPH Steady State Conditions
Original M100
Test
Number
1
2
Average
HC CO
q/mi g/mi
23.07 3.94
19.08 4.92
21.08
4.43
NOx
g/mi
1.90
2.11
2.01
Best Driveability PROM
Aide
mg/mi
1370.
1149.
1259.
0
0
5
HC*
g/mi
2.714
2.245
2.480
CH3OH*
g/mi
62.67
51.85
57.26
OMHCE*
g/mi
30.49
25.23
27.86
Lambda
1.38
1.30
1
.34
Improved Ml00 Best Driveability PROM
Test
Number
1
2
Average
HC
g/mi
17.15
17.32
17.24
CO
g/mi
3.
3.
3.
63
61
62
NOX
g/mi
1
1
1
.69
.90
.80
Aide
mg/mi
624.9
540.8
582.9
HC*
g/mi
2.017
2.038
2.028
CH30H*
g/mi
46
47
46
.58
.05
.82
OMHCE*
g/mi
22.
22.
22.
48
66
57
Lambda
1.32
1.30
1.31
Ml00 Maximum Lean Limit PROM
Test
Number
1
2
3
4
5
Average
HC
g/mi
21.09
15.53
13.85
16.17
16.75
16.68
CO
g/mi
4.79
5.04
4 .66
3.83
3.76
4.42
NOx
g/mi
l
l
1
l
l
. 11
.08
.96
.50
.45 •!
.22
Aide
mg/mi
1077
1049
1364
1174
1155
1164
.5 2
.5 1
.9 1
.6 1
.0 1
.3 1
HC*
g/mi
.481
.827
.629
.903
.970
.962
CH3OH*
g/mi
57.29
42.19
37.62
43.94
45.50
45.31
OMHCE*
g/mi
27
20
18
21
22
22
.79
.58
.55
.47
.21
. 12
Lambda
1.36
1.32
1.30
1.56
1.38
1.38
Calculated per proposed rulemaking.
-------
-29-
Test
Number
1
2
3
Average
Table 20
20 MPH Steady-StateConditions
Oriqinal M100
HC
q/mi
13.41
11.20
10.17
11.
59
CO
q/mi
2.09
2.15
2.76
2.33
NOx
q/mi
1.90
1.08
2.09
1.69
Best
Driveabilitv PROM
Aide
mq/mi
229.4
515.7
820.8
522.
0
1
1
1
1
HC*
q/mi
.578
.318
.197
.364
CH30H*
q/mi
36.44
30.44
27.64
31.51
OMHCE*
q/mi
17.46
14.74
13.55
15.25
Lambda
1
1
1
1
.36
.30
.30
.32
Improved Ml00 Best Driveability PROM
Test
Number
1
2
Average
Test
Number
1
2
3
4
5
Average
HC
q/mi
12.62
11.73
12.18
HC
q/mi
10.92
8.71
12.85
11.49
9.69
10.73
CO
q/mi
2.28
2.10
2.19
M100
CO
q/mi
3.03
2.83
2.61
2.05
2.04
2.51
NOX
q/mi
1.87
2.41
2.14
Aide
mq/mi
213.2
228.3
220.8
Maximum Lean
NOx
q/mi
1.18
1.09
1.08
.99
1.63
1.19
Aide
mq/mi
836.5
712.3
455.5
626.7
495.5
625.3
HC*
q/mi
1.485
1.380
1.433
Limit
HC*
q/mi
1.285
1.025
1. 512
1.351
1.140
1.263
CH30H*
q/mi
34.29
31.86
33.08
PROM
CH30H*
q/mi
29.67
23.66
34.92
31.21
26.33
29.16
q/mi Lambda
16.43 1.34
15.28 1.32
15.85 1.33
OMHCE*
q/mi
14.52
11.60
16.85
15. 16
12.77
14.18
Lambda
1.36
1.32
1.38
1.78
1.42
1.45
Calculated per proposed rulemaking.
-------
-30-
Table 21
30 MPH Steady-State Conditions
Original MlOO Best Driveabi1ity PROM
Test
Number
HC
g/mi
1 8.82
2 6.35
3 4.57
Average 6.58
1.95
NOx Aide
g/mi rag/mi
2.31 371.7 1.038
N/A 451.2 .747
1.53 583.6 .538
1.92 468.8 .774
CH30H* OMHCE*
g/tni g/mi Lambda
23.97 11.59
17.26 8.43
12.42 6.18
17.88 8.73
1.30
1.28
Improved MlOO Best Driveability PROM
Test
Number
1
2
Average
Test
Number
l
2
3
4
Average
HC
g/mi
7.22
8.16
7.69
HC
g/mi
2.90
4.22
4.07
3.08
3.57
CO
g/mi
1.90
1.64
1.77
MlOO
CO
g/mi
2.08
2.22
2.11
1.87
2.07
NOX
g/mi
1.98
2.43
2.21
Aide
mg/mi
130.3
127.0
128.7
Maximum Lean
NOx
g/mi
1.23
1.18
1. 13
1.40
1.24
Aide
mg/mi
482.3
411.7
250.4
206.0
337.6
HC*
g/mi
.849
,961
.905
Limit
HC*
g/mi
.342
.497
.478
.362
.420
CH3OH*
g/mi
19.62
22.18
20.90
PROM
CH30H*
g/mi
7.89
11.47
11.05
8.37
9.70
OMHCE*
g/mi
9.40
10.62
10.01
OMHCE*
g/mi
3.98
5.65
5.38
4.08
4.77
Lambda
1.30
1.32
1.31
Lambda
1 .28
1.30
1.58
1.38
1.39
* Calculated per proposed rulemaking.
N/A signifies not available.
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-31-
Table 22
40 MPH Steady-State Conditions
Original M1QO Best Driveability PROM
Test HC CO NOx
Number q/mi q/mi q/mi
1.65
1.78
1.80
1.37
1.72 1.59
Aide HC* CH30H* OMHCE*
mq/mi q/mi q/mi q/mi Lambda
314.9 .269 6.21
377.0 .319 7.37
346.0 .294 6.79
3.10 1.24
3.69 1.32
3.40 1.28
Improved MlOO Best Driveability PROM
Test
Number
1
2
Average
HC
f/mi
.64
1.51
1.58
CO
q/mi
1.66
1.75
1.71
NOx
q/mi
2.08
2.07
2.08
Aide
mq/mi
84.2
95.8
90.0
HC*
q/mi
.429
.413
.421
CH30H*
q/mi
9.90
9.55
9.73
OMHCE*
q/mi
4.76
4.59
4.68
Lambda
1.28
1.28
1.28
MlOO Maximum Lean Limit PROM
Test
Number
1
2
3
4
Average 2.61 1.75 1.40 212.2
HC
q/mi
1.61
1.53
1.80
5.48
CO
q/mi
1.58
1.62
1.71
2.07
NOx
q/mi
1.38
1.58
1.26
1.37
Aide
mq/mi
323.3
153.3
262.3
110.0
HC*
q/mi
. 189
. 179
.212
.645
CH30H*
q/mi
4.37
4.14
4.89
14.89
OMHCE*
q/mi
2.23
2.04
2.45
7.14
306
7.07 3.47
Lambda
1.28
1.29
1.58
1.40
1.39
Calculated per proposed rulemaking.
-------
Test
Number
1 5.24
2 1.24
3 3.46
Average 3.31
-32-
Table 23
50 MPH Steady State Conditions
Original M100
CO
q/mi
1.68
1.48
1.96
1.71
NOx
q/mi
1.53
1.44
NA
1.49
Best Driveability PROM
Aide
mq/mi
372.7
245.8
388.4
335.6
HC*
q/mi
.616
.145
.407
.389
CH30H*
q/mi
14.23
3.36
9.40
9.00
OMHCE*
q/mi
6.95
1.71
4.66
4.44
Lambda
Improved M100 Best Driveability PROM
Test
Number
l
2
Average
g
2
4
3
HC
/mi
.14
.57
.36
CO
q/mi
1
1
1
.60
.61
.61
NOX
q/mi
i
i
1
.75
.86
.81
Aide
mq/mi
62.8
63.6
63.2
HC*
q/mi
.252
.537
.395
CH30H* OMHCE*
q/mi
5.82
12.41
9.12
q/mi
2.80
5.94
4.37
Lambda
1.30
1.30
1.30
Ml00 Maximum Lean Limit PROM
Test
Number
1
2
3
4
Average
HC
q/mi
.95
1. 17
1.16
1.58
1.22
CO
q/mi
1.35
1.48
1.47
L.75
1.51
NOX
q/mi
1.62
1. 14
1 . 17
1.11
1.26
'Aide
mq/mi
253.
243.
293.
211.
250.
1
6
6
1
4
HC*
q/mi
.112
.137
.137
. 186
.143
CH30H*
q/mi
2.58
3.16
3. 16
4.30
3.30
OMHCE*
q/mi
1.35
1.62
1.64
2.15
1.69
Lambda
1.30
1.30
1.32
1.44
1.34
* Calculated per proposed rulemaking.
NA signifies test results not available.
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-33-
1. An improved version of the M100 best driveability
calibration was tested and the results compared with those from
testing with the PROM originally supplied with the vehicle.
Toyota describes the improved best driveability calibration as
8 percenj? leaner at idle than the original best driveability
calibration. NOx and CO emission levels over the FTP and HFET
cycles rose when the improved calibration was used. Aldehydes
and hydrocarbons remained at similar emission levels regardless
of calibration, however. Composite gasoline equivalent fuel
economy was 39.4 MPG for both calibrations.
2. The Carina was tested with an underfloor converter
in addition to its original close-coupled manifold converter.
Substantial increases in emission level efficiencies over
manifold catalyst-only testing were obtained for HC, CO, and
aldehydes over the FTP cycle. The two-catalyst system emitted
only 5 milligrams per mile of formaldehyde over the FTP, but
NOx emissions increased to 1.45 grams per mile over the same
cycle. Gasoline equivalent composite fuel economy was 38.8 MPG
with the two-catalyst system.
3. The Carina was tested over FTP/HFET cycles at an
inertia weight of 2625 Ibs, up from the 2250 Ibs inertia weight
tested at previously. CO levels over the FTP increased to 1.26
grains per mile, up from the 0.93 grams per mile emitted at 2250
Ibs test weight. Little change in other emission levels over
the FTP or HFET cycle resulted from the additional test
weight. City and highway fuel economy were reduced by 0.3 and
0.7 MPG respectively due to the increased weight.
4. The original equipment 165SR13 tires on the front
drive wheels were replaced with higher aspect ratio 175/80R13
tires. Efficiencies decreased by 16 to 50 percent in each
emissions category through the use of the higher tires. City
fuel economy was also penalized approximately 5 percent or 0.8
MPG by the use of the higher tires.
5. The vehicle was soaked and tested at colder than
75°F conditions to determine: a) the lowest temperature at
which the vehicle would start and run on M100 fuel, and b) the
emissions and fuel economy profiles of this vehicle at lower
than 75°F conditions.
The lowest temperature at which the Carina would start and
run reliably was 55°F. Emissions of carbon-containing
pollutants generally increased as soak temperature decreased
over the FTP cycle; average NOx emissions decreased over the
same range, however. Fuel economy gradually decreased with
decreasing soak temperature.
-------
-34-
6. The close-coupled manifold catalyst was removed and
a non-catalyzed substrate substituted in its place to
approximate engine-out, or baseline emissions. Three
electronically controlled air/fuel ratio calibrations were
utilized! in this testing: a) a calibration optimized for
driveability, b) a calibration similar to the first, yet 8
percent leaner at idle according to Toyota, and c) a
calibration for operation at the maximum lean limit.
HC baseline levels from the Carina ranged from 7.2 to 7.7
grams per mile over the FTP; CO was emitted at a rate of 5.4 to
5.9 grams per mile over the same cycle. Average formaldehyde
levels over the FTP varied from 312 milligrams per mile with
the improved best driveability calibration to 573.1 milligrams
per mile with the original best driveability calibration. The
lowest HC, CO and formaldehyde levels over the FTP were emitted
when the improved best driveability PROM was utilized. Higher
levels of NOx, over those from the original best driveability
and maximum lean limit calibrations, however were emitted when
the improved best driveability calibration was used. Gasoline
equivalent composite MPG was highest, 40.2 MPG, with the
maximum lean limit calibration.
7. An air/fuel ratio measuring system, described in
Appendix C was used to characterize the lean operating
conditions of the Carina over several steady-state cycles.
Three separate air/fuel ratio calibrations were utilized, and
pollutant emissions were also measured. Actual dynamometer
horsepower of 8.0 and vehicle inertia test weight of 2250 Ibs
were used for this testing.
The air/fuel ratio measuring technique employed did not
indicate that the improved best driveability PROM was 8 percent
leaner at idle than the original best driveability PROM.
Values of lambda (actual air/fuel ratio divided by
stoichiometric air/fuel ratio) from each calibration were
similar over idle cycle testing. The original and improved
best driveability calibrations ran at lambda values of 1.0 at
idle, while the maximum lean limit PROM ran leaner, at
approximately 1.14.
The two best driveability calibrations operated at lambda
values of approximately 1.3 over the 10, 20, 30, 40 and 50 MPH
steady-state cycles, which equates to an M100 air/fuel ratio of
approximately 8.4 to 1. The maximum lean limit calibration
operated at very near a lambda of 1.4 for these same cycles,
which equates to an M100 air/fuel ratio of approximately 9.0 to
l.
HC, NOx, and formaldehyde levels at idle were similar
among the three PROMs: approximately 0.6 and 0.4 grams per
minute and 50 to 80 milligrams per minute, respectively. CO
emissions with the maximum lean limit PROM, 0.41 grams per
minute, were less than 30 percent of the emission levels from
the best driveability PROMs, however.
-------
-35-
NOx levels at 10 MPH were 1.22 grains per mile with the
lean limit PROM, approximately 30 percent below levels from the
other PROMs. HC and CO levels were similar over all three
calibrations. Aldehyde emissions approached an average 600
milligrams per mile with the improved best driveability
calibration; the other two calibrations emitted at roughly
twice this level. This difference in aldehyde levels, due
solely to the air/fuel ratio calibration dissimilarities, is
difficult to explain, particularly the difference between the
two best driveability calibrations.
Average aldehyde values did not exceed 650 milligrams per
mile for any calibration over the 20, 30, 40, and 50 MPH
cycles, considerably lower levels than the emission rates
reported at 10 MPH conditions. CO emissions did not exceed an
average 2.5 grams per mile with any calibration over these
cycles, and average CO emission rates generally decreased as
speed increased with each calibration. Emissions measured as
HC also generally decreased as speed increased with each
calibration over these cycles.
Future work in this area should include an effort at
mapping excess air ratio (lambda) over at least two additional
parameters: intake manifold pressure and engine speed.
Air/fuel ratio analysis presented in the literature typically
involves mapping over these parameters. A direct comparison of
data gathered by the method described in Appendix C with other
published data is difficult in the absence of this format.
VII. Acknowledgment s
The author wishes to thank the Toyota Motor Company for
providing the T-LCS-M Carina vehicle that was used in this
evaluation.
The author also gratefully acknowledges the efforts of
James Garvey, Ernestine Bulifant, Steven Halfyard, and Robert
Moss, technicians, all of the Test and Evaluation Branch,
Emission Control Technology Division. The efforts of Marilyn
Alff and Jennifer Criss of the Control Technology and
Applications Branch, ECTD, who typed this manuscript, are also
appreciated.
-------
-36-
VIII.References
1. "Development of Toyota Lean Combustion System,"
Kobayashi, N. , et al., Japan Society of Automotive Engineering
Review, pp. 106-111, July 1984.
2. "NOx Reduction Is Compatible With Fuel Economy
Through Toyota's Lean Combustion System," Kimbara, Y., K.
Shinoda, H. Koide and N. Kobayashi, SAE Paper 851210, October
1985.
3. "Lean Mixture Sensor," Kamo, T. , Y. Chujo, T.
Akatsuka, J. Nakano and M. Suzuki, SAE Paper 850380, February
1985.
4. "Effects of Helical Port With Swirl Control Valve On
the Combustion and Performance of S.I. Engine," Matsushita, s.,
T. Inoue, K. Nakanishi, T. Okumura and K. Isogai, SAE Paper
850046, February 1985.
5. "Development of Methanol Lean Burn System," Katoh,
K., Y, Imamura and T. Inoue, SAE Paper 860247, February 1986.
6. "Fuel Economy and Emissions of a Toyota T-LCS-M
Methanol Prototype Vehicle," Piotrowski, G. and J. D. Murrell,
SAE Paper 871090, May 1987.
7.- Cold Room Testing of LCS-M Vehicle, Memorandum,
Piotrowski, G. K. OAR, OMS, ECTD, Ann Arbor, MI, 1987.
8. Phase II Testing of LCS-M Vehicle, Memorandum,
Piotrowski, G. K., OAR, OMS, ECTD, Ann Arbor, MI, 1987.
9. Manifold and Underfloor Converter Testing On Toyota
LCS-M Carina, Memorandum, Piotrowski, G. K. , OAR, OMS, ECTD,
Ann Arbor, MI, 1987.
10. Summary of Fuel Economy Data, Recent Toyota LCS-M
Carina Testing, Memorandum, Piotrowski, G. K. , OAR, OMS, ECTD,
ann Arbor, MI, 1987.
11. "Proposed Emission Standards and Test Procedures for
Methanol-Fueled Vehicles, Draft Regulation," U.S. EPA, Federal
Register, Vol. 51, No. 168, August 29, 1986.
12. Formaldehyde Measurement In Vehicle Exhaust At MVEL,
Memorandum, Gilkey, R. L., OAR, OMS, EOD, Ann Arbor, MI, 1981.
13. "Catalysts For Methanol Vehicles," Piotrowski, G. K.
and Murrell, J. D., SAE Paper 872052, November, 1987.
-------
A-l
APPENDIX A
DESCRIPTION OF TOYOTA LCS-M TEST VEHICLE
vehicle
Transmission
Shift speed code
Fuel
Number of cylinders
Displacement
Camshaft
Compression ratio
Combustion chamber
Fuel Metering
Bore and Stroke
Ignition
Ignition timing
Fuel injectors
Fuel pump
2015 Ibs
Manual, 5 speed
15-25-40-45 mph
M85 or M100
Four, in-line
97 cubic inches
Single, overheau. camshaft
11.5, flat head pistons
Wedge shape
Electronic port fuel injection
3.19 inches x, 3.03 inches
Spark ignition; spark plugs
are ND W27ESR-U, gapped at .8
mm, torqued to 13 ft-lb.
With check connecter shorted,
ignition timing should be set
to 10°BTDC at idle. With
check connecter unshorted,
ignition timing advance should
be set to 15°BTDC at idle.
Idle speed is approximately
550-700 rpm.
Main and cold start fuel
injectors capable of high fuel
flow rates. The fuel injector
bodies have been nickel-
plated, and the adjusting
pipes are stainless steel.
In-tank electric fuel pump
with brushless motor to
prevent corrosion. The body
is nickel plated and its fuel
delivery flow rate capacity
has been increased.
-------
A-2
APPENDIX A (cont'd)
DESCRIPTION OF TOYOTA LCS-M TEST VEHICLE
Fuel tank Stainless steel construction;
capacity 14.5 gals.
Fuel lines and filter The tube running from the fuel
tank to the fuel filter has
been nickel plated. The fuel
filter, located in the engine
compartment, has also been
nickel plated. The fuel
delivery rail has been plated
with nickel-phosphorus.
Catalytic converter l-liter volume, Pt:Rh loaded,
close coupled to the exhaust
manifold.
-------
B-l
APPENDIX B
CALCULATION OF HC. METHANOL AND HCHO
As proposed, the regulations in reference 7 require the
measurement of methanol (CHjOH) and formaldehyde (HCHO).
Methanol emissions are especially important since the dilution
factor equation includes CHjOH emissions. At the time the
test results reported here were made, the EPA lab did not
measure CHsOH. Therefore, the results in this paper were
computed with an assumed FID response factor of 0.75 and an
assumed HC ppm to methanol ppm factor of xx/.85, where xx is
the fraction of methanol in a methanol gasoline blend.
-------
C-l
APPENDIX C
NTK MICRO OXIVISION AIR/FUEL RATIO METER
The MICRO OXIVISION MO-1000 is an air/fuel ratio meter
designed specifically for use with the NTK Universal Exhaust
Gas Oxygen Sensor.
The detecting section of the sensor is made of two Zr02
substrate elements: 1) an Oj pumping cell, and 2) an O2
detecting cell, both heated by ceramic heaters. Zr02 has two
interesting properties with respect to its use as a sensor.
First, a galvanic potential is caused by different 02 partial
pressures on either side of a ZrO2 element. Second, an
oxygen ion may be moved by applying voltage to the Zr02
element.
The detecting cell contains two chambers. The first, or
reference cavity contains a high concentration of oxygen. The
othe side of the detector is exposed to exhaust gas, and is
referred to as the detecting gas cavity. The separation of
these two cells by a Zr02 element generates a galvanic
potential voltage in the same fashion as a conventional oxygen
sensor. The galvanic potential is approximately lOOmV at very
lean conditions and may rise to 900 mV under rich conditions.
The pumping cell can control the partial 02 pressure in
the gas detecting cavity by pumping 02; therefore, it may
also control galvanic potential. This potential may be held at
450 mV in any exhaust condition by controlling current to the
pumping cell, and therefore the pumping current corresponds to
the air/fuel ratio of the exhaust gas.
Further information concerning the operation of the sensor
is available from the U.S. distributor of this product, NGK
Spark Plugs (U.S.A.), Inc.
-------
C-2
. APPENDIX C (cont'd)
NTK MICRO OXIVISION AIR/FUEL RATIO METER
Specifications
Sensor Specification (MB-1QO) :
Measurement Range:
Lambda
Air/Fuel Ratio
02 Partial Pressure
Accuracy and Repeatability:
Lambda
Measurement Range
other
Air Fuel Ratio:
Measurement Range
13
-------
C-3
Specifications (cont'd)
Meter Specifications (MO-100Q):
Sensor Operation System:
Icp Current
Vs Voltage
Limit of pumping current
Heater supplied voltage
Data Processing System:
Sample Period
Measurement for Pumping
Current of Sensor
25+3 micro A
450 mV
- 12.5 -
12.5 mA
10.5 + 0.5V DC
10 msec
12 Bit A/D
Readout Equipment Details:
4 digit LED
Lambda
Air Fuel Ratio
02%
Function
Analog Output Voltage:
Connector:
Display:
Function:
Indication Range
0.500-2.290 X
4.00-33.30 A/F
0.00-22.00%0Z
Running Average:
0.5 sec.; 2.0 sec
and HOLD
Resolution
0.001*
0.01 A/F
0.01%02
10.0 sec.;
BNC connector (0.5V)
Same as readout
Real time, the running average between
2.0 and 10.0 sec.
The readout gain of A/F can be selected
corresponding to 0 - 5V
Range of Usage:
Sensor Gain
Hydrogen/Carbon Ratio of Fuel
Oxygen/Carbon Ratio of Fuel
Power Source:
AC 90 - 126V
(dp. AC 180 - 260V
DC12 - 16V
000-999
0.00-9.99
0.00-9.99
2A
1A)
5A
DC Power Cord
White Wire
Black Wire
Connector:
Power line connector
Sensor harness
connector
Positive
Negative (-) or ground
TEA spec.
NANA BOSHI
NJC 20A alpha - 7
Environmental Operating Conditions:
Temperature 5 - 45°C
Humidity 15 - 80% R.H. (non-condensing)
Physical Size:
250mm W x 100mm H x 300mm D
Weight 4.6 Kg
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