EPA/AA/CTAB/90-02
Technical Report
Recent Results From Prototype Vehicle
Technology Evaluation Using M100 Neat Methanol Fuel
by
Gregory K. Piotrowski
March 1990
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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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
ANN ARBOR MICHIGAN 48105
MAR 21 1990 OFFICE OF
AIR AND RADIATION
MEMORANDUM
SUBJECT: Exemption From Peer and Administrative Review
FROM: Karl H. Hellman, Chief
Control Technology and Applications Branch
TO: Charles L. Gray, Jr., Director
Emission Control Technology Division
The attached report entitled "Recent Results From
Prototype Vehicle Technology Evaluation Using M100 Neat
Methanol Fuel," (EPA/AA/CTAB/90-02) describes the evaluation of
two prototype MIOO-fueled vehicles. Emissions and fuel economy
test results from both vehicles are presented and compared here.
Since this report is concerned only with the presentation
of data and its analysis and does not involve matters of policy
or regulations, your concurrence is requested to waive
administrative review according to the policy outlined in your
directive of April 22, 1982.
Concurrence : -^ •* '--•- ' - ''-• ..- _ Date : 3 — I "7"^ I)
Charles L. Gray, Jr/, Dir., ECTD
Nonconcur rence : _ Date:
Charles L. Gray, Jr., Dir., ECTD
cc: E. Burger, ECTD
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Table of Contents
Page
Number
I. Summary 1
II. Introduction 2
III. Test Vehicle Descriptions 3
A. Toyota Corolla Vehicle 3
B. Nissan Sentra Vehicle 3
IV. Test Facilities and Analytical Methods 4
V. Evaluation Process 4
VI. Discussion of Test Results 5
A. Vehicle Emissions 5
B. Fuel Economy and Performance Testing 10
VII. Highlights From Testing 18
VIII. Future Efforts 19
IX. Acknowledgments 20
X. References 21
Appendix A: Description of Toyota Corolla Prototype
Vehicle A-l
Appendix B: Description of Nissan Sentra
Prototype Vehicle B-l
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I. Summary
The Toyota Motor Corporation and the Nissan Motor
Corporation recently supplied the U.S. Environmental Protection
Agency (EPA) with advanced prototype vehicles which utilize
M100 (neat methanol) fuel. These vehicles both make use of
nominal lean burn calibrations controlled by an exhaust gas
air/fuel sensor feedback control system and 4 valve per
cylinder technology in 4-cylinder powerplants. Though these
vehicles share these similar technological aspects, important
differences between both engine/vehicle packages yet exist.
These two prototype vehicles have been evaluated by EPA
for emissions and fuel economy. Nissan also supplied EPA with
a gasoline-fueled vehicle for fuel economy and performance
testing and comparison. The results from this preliminary
round of testing are given here.
Both prototype vehicles achieved low emission levels over
the Federal test procedure (FTP), at low mileage, of
hydrocarbon, methanol, formaldehyde and organic material
hydrocarbon equivalent emissions. Particularly noteworthy were
the lower emissions of formaldehyde (9.0 milligrams per mile)
and organic material hydrocarbon equivalents (0.12 grams per
mile) over the FTP by the M100 lean burn Toyota Corolla. The
M100 lean burn Nissan Sentra vehicle had very low emissions of
carbon monoxide (0.45 grams per mile) over the FTP.
The gasoline equivalent fuel economy of the M100 Sentra
was compared to that from a gasoline-fueled Nissan Pulsar
equipped with a similar base engine. The M100 Sentra was
evaluated at the same test weight, actual dynamometer
horsepower and nominally equivalent N/V (rpm/MPH in top gear)
ratio as the gasoline-fueled vehicle. The fuel economy of the
M100 vehicle was also performance adjusted to eliminate the
effects of this difference between the two fuels.
The methanol-fueled vehicle had a combined city/highway
gasoline equivalent fuel economy approximately 47 percent
greater than the gasoline-fueled comparison vehicle under these
conditions.
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II. Introduction
The U.S. Environmental Protection Agency (EPA) has been
interested in methanol as an alternative motor vehicle fuel
because of its environmental benefits over the continued use of
gasoline. Methanol may be particularly attractive as an
automotive fuel in areas of high ozone level occurrences
because of its lower ozone-producing potential.[1] Methanol
may also offer air quality benefits over gasoline with respect
to a wide variety of organic air toxics.[2]
The Toyota Motor Corporation has provided substantial
technical assistance to U.S. EPA efforts involving the use of
methanol as a motor vehicle fuel. One part of this assistance
was the consignment for technical evaluation to EPA of a Toyota
Lean Combustion System-Methanol (T-LCS-M) Carina vehicle.
Technical detail for this vehicle may be found in the
literature.[3,4] This vehicle was initially evaluated for
emissions and fuel economy and has been used in several
emissions control technology evaluation efforts.[5,6,7,8,9]
A second-generation methanol-prototype vehicle has been
produced by Toyota.[10] This prototype utilized both lean
combustion, lean feedback air/fuel ratio control, and exhaust
gas recirculation. The 4 valve per cylinder configuration
results in a relatively compact combustion chamber for this
engine. A significant goal of this research effort was to
determine the feasibility of achieving 0.4 grams per mile NOx
levels over the 1975 Federal test procedure (FTP) with this
methanol-fueled lean burn engine.
EPA requested that Toyota provide a second generation
methanol lean burn vehicle for evaluation and research
assistance. Toyota provided EPA with a second-generation
methanol lean burn system in a Corolla vehicle. This vehicle
may operate on either M100 neat methanol or M85 blended
methanol/gasoline fuel depending upon which of two provided
calibrations is used.
The Nissan Motor Corporation has also provided substantial
technical assistance to EPA with respect to alternative fuels
research. Nissan technology has been used in several recent
EPA efforts involving methanol-fueled vehicle
technology.[11,12,13] Nissan also designed and produced a
recent prototype methanol vehicle incorporating lean burn
operation and 4-valve-per-cylinder technology. Upon request,
Nissan provided EPA with a prototype methanol vehicle for
evaluation and research. Nissan also lent a gasoline-fueled
Pulsar vehicle to EPA to assist with an effort to compare
gasoline equivalent fuel economy from a methanol-fueled vehicle
to that from a comparable gasoline vehicle.
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Preliminary emissions and fuel economy evaluations have
been made of each of these vehicles on M100 fuel. Limited
performance testing on each vehicle has also been conducted.
The purpose of this report is to present and compare test data
from each of these evaluations.
Ill. Test Vehicle Descriptions
A. Toyota Corolla Vehicle
The Toyota Corolla vehicle evaluated here was equipped
with the second-generation Toyota methanol lean burn system as
described in SAE Paper 892060.[10] The Corolla vehicle
delivered to EPA was capable of operation on both M100 neat and
M85 blended methanol fuels by changing calibrations. The data
in this paper, however, is concerned only with operation on
M100 neat methanol.
The base engine chosen by Toyota for the second-generation
methanol lean burn system was the 1.6-liter 4A-FE,
incorporating 4-valve/cylinder and compact combustion chamber
technology.[14] The swirl control valve system, lean mixture
sensor and sequential fuel injection, all essential components
of the first lean burn system, were retained.[4] In addition,
exhaust gas recirculation (EGR) was added in an attempt to
further lower NOx emissions. A palladium underfloor catalyst
was also incorporated in addition to the platinum:rhodium
manifold close-coupled converter, in an attempt to lower
formaldehyde emissions.
Detailed specifications are provided in Appendix A.
B. Nissan Sentra Vehicle
The Nissan test vehicle evaluated here is similar to the
Toyota vehicle in that it utilizes a 4-valve/cylinder,
4-cylinder in-line base engine with a lean burn operating
scheme. Electronic port fuel injection and swirl control
valves are also incorporated, as in the Toyota vehicle.
While the general engine schemes are similar for the two
test vehicles, many important differences also exist. For
example, the Nissan engine is slightly larger in displacement
at 1.8 liters and has a higher compression ratio (12.0:1)
compared to 11.0:1 for the Toyota engine. The Sentra vehicle
was tested at a lower test weight of 2,250 Ibs as suggested by
Nissan. A single underfloor Pt:Rh catalyst was used by Nissan
instead of the two-catalyst system used by Toyota on the
Corolla vehicle.
A detailed list of specifications for this vehicle is
given in Appendix B.
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IV. Test Facilities And Analytical Methods
Emissions testing at EPA was conducted on a Clayton Model
ECE-50 double-roll chassis dynamometer using a direct-drive
variable inertia flywheel unit and road load power control
unit. The Philco Ford constant volume sampler used had a
nominal capacity of 350 CFM. 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 by a Beckman Model
951A chemiluminescent NOx analyzer.
Exhaust formaldehyde was measured using a dinitrophenyl-
hydrazine (DNPH) technique.[15,16] 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 a
sample of the dilute exhaust or evaporative emissions are
pumped. 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 (GO
analysis.C17]
Most of the emission results in this report 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 these specialized procedures and calculation
methods are not in widespread use, we have also included a
hydrocarbon result, which is what would be obtained if the
exhaust was treated as if the fuel were gasoline. This is done
as a convenience for the readers and users of the report who
may be more familiar with hydrocarbon results obtained this way.
V. Evaluation Process
The initial evaluation process reported on here consisted
of emissions and fuel economy testing, followed by limited
performance testing.
Both prototype vehicles were evaluated for emissions and
fuel economy several times over the FTP and highway fuel
economy test (HFET) cycles. Limited performance testing
consisting of 5-60 miles per hour (MPH) acceleration tests on a
chassis dynamometer were also conducted at several vehicle test
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weights and actual dynamometer horsepower settings. Wide open
throttle (WOT) and 5,000 rpm shift points were used during this
testing. The purpose of this testing was to assist in relating
performance to fuel economy. The gasoline-fueled Pulsar
provided by Nissan mentioned earlier was used here as a control
vehicle.
VI. Discussion of Test Results
A. Vehicle Emissions
Upon arrival at the EPA Motor Vehicle Emission Laboratory
(MVEL) both vehicles were tested approximately eight times over
the FTP with M100 fuel. Average emission levels from this
testing with both cars are presented in Table 1.
It is important to note that although both prototype
vehicles referred to have significant basic technologies in
common, e.g., lean operation, use of 4-valve/cylinder
technology, etc., many fundamental differences between the two
remain. These fundamental differences will significantly
impact the emissions and fuel economy profiles of these two
vehicles. No attempt is made in this report to quantify the
effect of these differences on emissions and fuel economy.
Instead, the data is presented in comparative fashion to
provide an indication of what low mileage emissions and fuel
economy levels might be expected from state-of-the-art
MIOO-fueled vehicles equipped with premixed charge spark
ignition engines.
The emissions levels from both vehicles may generally be
described as being lower than the levels specified by exhaust
emissions standards for light-duty methanol-fueled vehicles for
the model year 1990.[18] Hydrocarbon (HC) emissions from both
vehicles were approximately the same, at 0.02 grams per mile.
Organic material hydrocarbon equivalents (OMHCE) were slightly
higher, for example 0.20 grams per mile, from the Sentra
vehicle. Both prototype vehicle OMHCE levels were
substantially under the current 0.41 grams per mile standard,
however.
Methanol emissions from the Corolla vehicle were very low
over the FTP. The emissions of 0.22 grams per mile approach
the levels of a stoichiometric air/fuel ratio MIOO-fueled
vehicle equipped with a very effective resistively heated fast
light-off catalyst.[19] CH,OH emissions from the Sentra
vehicle were higher, at an average 0.40 grams per mile.
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Table 1
MIOO-Fueled Nissan/Toyota
Prototype Lean Burn Vehicles
Exhaust Emissions Over the FTP Cycle
HC* HC** NMHC OMHCE CH3OH CO NOx HCHO
Vehicle (q/mi) (q/mi) (q/mi) (q/mi) (q/mi) (q/mi) (q/mi) (mq/mi)
Toyota Corolla 0.09 0.02 0.01 0.12 0.22 1.61 0.49 9.0
with 4A-FE
lean burn
engine
Nissan Sentra 0.15 0.02 0.02 0.20 0.40 0.45 0.56 28.9
with CA18DE ***
lean burn
engine
* Measured as hydrocarbons with a propane-calibrated FID.
** Calculated per "Final Rule for Methanol-Fueled Motor. Vehicles and
Motor Vehicle Engines."
*** Less than 0.01 grams/mile CH4 measured.
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CO emission levels from the Corolla were substantially
higher than those of the Sentra vehicle. The 0.45 grams per
mile CO measured over the FTP with the M100 Sentra were low
even when compared with CO levels from the stoichiometrically
calibrated methanol vehicle referred to previously [19] and a
gasoline-fueled vehicle, [20] both of which were equipped with
resistively heated catalytic converters.
NOx emissions from both vehicles were similar,
approximately one-half gram per mile over the FTP. These
levels are significantly below the 0.75 grams per mile obtained
with the first-generation Toyota lean combustion system
(methanol) when tested at low mileage on MlOO fuel at MVEL.[6]
It is interesting to note that these lower NOx levels were
attained without a perceptible degradation in driving
performance from the high level of performance of the
first-generation Toyota lean combustion system (methanol) noted
at MVEL, based on a subjective evaluation of vehicle
driveability.
Formaldehyde (HCHO) emissions from the Corolla vehicle
were similar to those from the first-generation Toyota- lean
combustion system (methanol) at low mileage.[5,6] The Sentra
had higher HCHO emissions levels of almost 29 milligrams per
mile over the FTP.
The major portion of pollutant emissions from a
catalyst-equipped methanol-fueled vehicle are generated during
cold start and prior to light off of the catalytic
converter.[21] These emissions are difficult to control
because engine-out emissions are high and catalytic converters
have low conversion efficiency during their warm-up phase of
operation. Any effort to significantly reduce emission levels
of unburned fuel, HCHO, and CO over the FTP will probably
involve a lowering of these catalyst prelight-off emissions.
One quick way to roughly gauge the effect of these
emissions over the FTP is to compare Bag 1 emission levels to
those from Bag 3. The difference in emission levels might be
attributed to this vehicle and catalyst warm-up phenomena.
Table 2 is a comparison of Bag 1 versus Bag 3 emission levels
from the Corolla and Sentra vehicles. The data from each
emission category is presented in grains per bag except for HCHO
which is given in milligrams per bag. Significant highlights
from this data are then presented in graphical form.
Figure 1 presents OMHCE and methanol emissions over Bags l
and 3, the cold start transient and hot start portions of the
FTP. The graphic display of the data makes apparent the large
difference in emissions of these pollutants attributable to
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Table 2
MIOO-Fueled Toyota Corolla
Bag 1 versus Bag 3 Emissions, FTP Cycle
Test Segment
Bag 1
Bag 3
Difference
Percent
Test Segment
Bag 1
Bag 3
Difference
Percent
HC*
(q)
1.30
0.11
1.19
92
Bag
HC*
(g)
2.87
0.03
2.84
99
HC**
(g)
0.21
0.05
0.16
76
NMHC
(g)
0.17
0.03
0.14
82
MIOO-Fueled
1 versus Bag 3
HC**
(g)
0.26
0.02
0.24
92
NMHC
(g)
0.23
0.01
0.22
96
OMHCE
(g)
1.72
0.13
1.59
92
CH3OH
«rf
3.37
0.18
3.19
95
Nissan Sentra
Emissions, FTP
OMHCE
(g)
3.79
0.04
3.75
99
CH3OH
(g)
6.61
0.04
6.57
99
CO
(g)
15.34
4.25
11.09
72
Cycle
CO
(g)
7.61
0.12
7.49
98
NOx
(g)
2.32
2.34
(0.02)
—
NOx
(g)
2.05
1.88
0.17
8
HCHO
(mg)
105.8
14.8
91.0
86
HCHO
(mg)
434.8
24.0
410.8
94
* Measured as hydrocarbons with a propane-calibrated FID.
** Calculated per "Final Rule for Methanol-Fueled Motor Vehicles and
Motor Vehicle Engines."
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Figure 1
Bag 1/Bag 3, CVS 75 (FTP)
OMHCE and Methanol Emissions
Car/Emission/Bag
OMHCE -
Corolla/Bag 1
Corolla/Bag 3 I 0.13
Sentra/Bag 1
Sentra/Bag 3 f-0.04
1.72
3.79
Methanol -
Corolla/Bag 1
Corolla/Bag 3 I 0.18
3.37
Sentra/Bag 1
Sentra/Bag 3 |-0.04
2 3 4 5 I
Grams (Bag 1/Bag 3)
6.61
7 8
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cold start. OMHCE levels from the Corolla during Bag 1 are
roughly 13 times the level determined over Bag 3. This
difference increases to almost a factor of 19 when methanol
emissions from this vehicle are considered. The difference
between Bags 1 and 3 levels of these emissions from the Sentra
vehicle are even more pronounced. The influence of cold start
on emissions of unburned fuel is clearly evident here.
This influence, as expected, extended to emissions of NMHC
and formaldehyde (HCHO). Emissions of NMHC were at roughly the
same level from both test vehicles; Figure 2 shows that Bag l
NMHC emissions from the Sentra prototype were 23 times higher
than Bag 1 emissions. HCHO emissions from both vehicles were
affected by cold start to an even greater extent if the percent
difference in emissions between the two phases is considered.
Emission levels of CO and NOx over Bags 1 and 3 are given
in Figure 3. The effect of cold start on emissions of CO from
the Sentra vehicle are especially pronounced. NOx emissions do
not differ much between Bags 1 and 3.
Table 3 presents emission averages from both vehicles over
the HFET cycle. Emissions from both vehicles are similar with
the exception that a slightly greater amount of CO was emitted
from the Corolla vehicle. These emission averages in grams per
mile were uniformly low; they are presented here in Table 3,
but not commented upon further.
For most emissions, further efforts at cleanup over the
FTP cycle would appear to require emphasis on emissions related
to cold start. This is true for emissions of methanol, HC,
HCHO, OMHCE, and CO from both vehicles evaluated here.
B. Fuel Economy and Performance Testing
Fuel economy data from the two MIOO-fueled test vehicles
is given in Table 4. The data is presented in two formats.
First, miles per gallon (MPG) in terms of methanol fuel is
presented, and then a gasoline equivalent fuel economy has been
calculated. These computations have been explained in a
previous paper;[6] the gasoline equivalent adjustment based on
fuel energy content is 2.0105 times the calculated M100
methanol fuel economy.
Table 4 also contains fuel economy data from
gasoline-fueled vehicles for comparison. The EPA 1990 Test Car
List was reviewed for Toyota and Nissan vehicles configured in
a similar manner to the MIOO-fueled prototypes. A Toyota
Corolla wagon was chosen as a vehicle reasonably comparable to
the MIOO-fueled Corolla. The gasoline-fueled vehicle also used
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Figure 2
Bag 1/Bag 3, CVS 75 (FTP)
NMHC and HCHO Emissions
Car/Emission/Bag
NMHC -
Corolla/Bag 1
Corolla/Bag 3
0.03
0.17
Sentra/Bag 1
Sentra/Bag 3 I 0.01
0.23
HCHO -
Corolla/Bag 1
Corolla/Bag 3 • 0.015
0.106
Sentra/Bag 1
Sentra/Bag 3
0.024
0.435
0.1 0.2 0.3 0.4
Grams (Bag 1/Bag 3)
0.5
Figure 3
Bag 1/Bag 3, CVS 75 (FTP)
CO and NOx Emissions
Car/Emission/Bag
CO
Corolla/Bag 1
Corolla/Bag 3
Sentra/Bag 1
Sentra/Bag 3 I- 0.12
NOx p
Corolla/Bag 1 •
Corolla/Bag 3 •
Sentra/Bag 1 jff
Sentra/Bag 3 H^
7.61
I 2.32
| 2.34
| 2.05
1.88
15.34
4 6 8 10 12 14 16 18
Grams (Bag 1/Bag 3)
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Table 3
MIOO-Fueled Nissan/Toyota
Prototype Lean Burn Vehicles
Exhaust Emissions Over the HFET Cycle
HC* HC** NMHC OMHCE CH*OH CO NOx HCHO
Vehicle (q/mi) (q/mi) (g/mi) (g/mi) (g/mi) (g/mi) (g/mi) (mg/mi)
Toyota Corolla 0.005 0.002 0.001 0.007 0.010 0.13 0.45 2.4
with 4A-FE
lean burn
engine
Nissan Sentra 0.004 0.001 —*** 0.007 0.012 0.01 0.48 2.2
with CA18DE
lean burn
engine
* Measured as hydrocarbons with a propane-calibrated FID.
** Calculated per "Final Rule for Methanol-Fueled Motor Vehicles and
Motor Vehicle Engines."
*** Calculated negative but assumed zero.
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Table 4
Fuel Economy Comparison of Toyota and Nissan
MIOO-Fueled Prototypes With "Equivalent"
Toyota and Nissan Gasoline-Fueled Vehicles
From the EPA 1990 Test Car List
A. Vehicle Specifications
Vehicle
M100 Corolla
Corolla Wagon
(gasoline)
M100 Sentra
Gasoline Pulsar
NX
Engine
97 CI, FI,
11.0 CR, EGR
97 CI, FI
110 CI, FI,
12.0 CR
110 CI, FI,
EGR, 9.5 CR
Trans- Dyno Test
Drive N/V mission HP Weight
8.9 2750
8.6 2750
7.3 2250
6.4 2875
FWD
FWD
FWD
FWD
46
46
44
53
.4
.4
.4
.6
M5
M5
M5
M5
B. Fuel Economy
Methanol Fuel Economy Gasoline Equivalent MPG Percent
Vehicle
M100 Corolla
Corolla Wagon
(gasoline)
M100 Sentra
Gasoline Pulsar
City
16.9
—
18.2
___
23.1
—
25.9
__
Combined
19.
—
21.
__
2
0
Cit
33.
31.
36.
24.
Y
9
0
6
9
Hv
46
42
52
37
y Combined
.4
.4
.1
.6
38
35
42
29
.6
.3
.2
.4
Diff .
+ 9%
Base
+44%
Base
NX
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the same final drive ratio (3.72) as the methanol-fueled
vehicle. A 1990 Nissan Pulsar NX was selected for comparison
to the MlOO-fueled Sentra. The Pulsar was equipped with the
same CA18DE base engine as the methanol-fueled Sentra and also
used a 5-speed manual transmission. The Pulsar referred to in
Table 4, however, was tested at a higher weight of 2,875 Ibs,
and utilized a higher axle ratio (4.47).
The MlOO Corolla had a combined city/highway gasoline
equivalent MPG approximately 9 percent higher than that of the
gasoline-fueled vehicle presented for comparison. The MlOO
Sentra had a combined city/highway fuel economy of 21.0 MPG of
methanol fuel; this figure was approximately 9 percent higher
than that from the Corolla. The gasoline equivalent fuel
economy of the Sentra (42.2 MPG) was significantly higher than
the gasoline-fueled Pulsar from the Test Car List. Overall,
the calculated gasoline equivalent fuel economies of the MlOO
vehicle appeared to equal or exceed the fuel economies of
roughly comparable gasoline-fueled vehicles. The differences
between these vehicles should be kept in mind, however, when
attempting a comparison between the fuels.
A further attempt to compare fuel economy from the
MlOO-fueled Sentra with a gasoline vehicle was made when Nissan
provided EPA with a 1988 gasoline-fueled Pulsar. This car was
used as a comparison vehicle, and an attempt was made to
eliminate differences in N/V ratio, test weight and road load
horsepower between the MlOO-fueled car and the gasoline
vehicle. The Pulsar utilized the base CA18DE powerplant.
Performance was also accounted for in this fuel economy
analysis.
Table 5 contains test data from the MlOO Sentra and
selected vehicles from EPA Test Car List. Case 1 compares the
MlOO Sentra with a 1990 Pulsar equipped with the same base
engine. This case is the same as the data presented in Table
4; an efficiency of +44 percent from the gasoline vehicle's
fuel economy is indicated. The Sentra was also compared to a
Pulsar from the 1987 Test Car List; this gasoline-fueled Pulsar
was tested at a higher actual horsepower, 7.1 hp. The percent
improvement in gasoline-equivalent fuel economy with the
methanol-fueled vehicle remained very close to that from
comparison to the 1990 Pulsar, approximately 45 percent.
Case 3 compared the Sentra tested at 7:1 actual
dynamometer horsepower and 2,875 Ibs ETW to the gasoline 1987
Pulsar. The results are similar to the first two cases: a 47
percent increase in gasoline equivalent fuel economy of the
MlOO Sentra over the Pulsar is indicated. The N/V ratio
(crankshaft speed in rpm over vehicle speed expressed in miles
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Table 5
Comparison of Nissan MIOO-Fueled Sentra
With Gasoline-Fueled Nissan Pulsar Vehicles
From EPA Test Car Lists
Case
1
1
2
2
3
3
4
4
Vehicle
M100
1990
M100
1987
M100
1987
M100
1987
Sentra
Pulsar
Sentra
Pulsar
Sentra
Pulsar
Sentra
Pulsar
Engine
CID ETW
110
110
110
110
110
110
110
110
2250
2875
2250
2875
2875
2875
2875
2875
Dyno
HP
7.3
6.4
7.3
7.1
7.1
7.1
7.1
7.1
Gasoline
N/V
44
53
44
53
44
53
53
53
.4
.6
.4
.6
.4
.6
.6*
.6
Equivalent
City
36.6
24.9
36
25
36
25
35
25
.6
.0
.8
.0
.3*
.0
Hv
52
37
52
36
53
36
49
36
MPG Percent
y Comb.
.1
.6
. 1
. 7
.8
.7
.4*
.7
42
29
42
29
42
29
40
29
.2
.4
.2
.2
.9
.2
.5*
.2
Diff .
+44%
+45%
+47%
+39%
Adjusted mathematically to infer results if tested at 53.6 N/V.
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per hour) of the MlOO Sentra was measured at EPA at 44.4; this
is lower than the N/V ratio of 53.6 for the 1987 Pulsar given
in the 1990 Test Car List. The MPG value of the Sentra was
mathematically adjusted to account for this difference.[22]
N/V sensitivities of 0.21 for city and 0.43 for highway MPG
were used. The result. Case 4, lowers the increase in MlOO
Sentra fuel economy to 39 percent above the Pulsar, still a
significant increase.
Table 6 compares fuel economy data from the MlOO Sentra
with a 1988 Pulsar equipped with a CA18DE engine provided by
Nissan as a comparison vehicle. Case 1 compares both vehicles
tested at 2,875 Ibs and 7.1 actual dynamometer horsepower. The
value of N/V for the Pulsar was 53.3, compared to the measured
N/V of 44.4 of the M100 Sentra. The lower combined MPG of 28.3
for the 1988 Pulsar caused the percent difference between the
M100 Sentra and gasoline Pulsar fuel economies to rise 52
percent above the level of the Pulsar.
EPA had the M100 Sentra modified to accept the same final
drive of the Pulsar (a final drive gear ratio of 4.167:1); this
caused the MlOO Sentra N/V to rise to 54.0. The only N/V
difference now between the two vehicles would be that
introduced by the tire outside diameters, and this would be
minimal.[22]
Case 2 in Table 6 compares the MlOO Sentra modified in
this manner to the gasoline-fueled Pulsar. The percent
increase in gasoline equivalent fuel economy enjoyed by the
methanol-fueled vehicle over the gasoline Pulsar decreased to
33 percent.
Finally, acceleration performance testing was conducted on
both vehicles to assist in the adjustment of fuel economy for
performance factors.[23] Both vehicles were tested using 5,000
rpm gear shift points and wide-open throttle (WOT)
acceleration. The measure of performance was determined to be
the time to accelerate at WOT from 5 to 60 MPH. Both cars were
equipped with manual transmissions for the shift sequence.
The Sentra fueled with MlOO was roughly 19 percent faster
than the Pulsar fueled with gasoline. The average 5-60 MPH
acceleration time for the MlOO Sentra was approximately 8.3
seconds; the Pulsar fueled with gasoline averaged 10.2 seconds
for 5-60 MPH acceleration. A sensitivity value of 0.454 [24]
was used to account for this difference in performance measured
by the difference in acceleration times, and the fuel economy
of the MlOO Sentra was adjusted accordingly. The comparison
between this adjusted MPG for the MlOO Sentra and the
gasoline-fueled Pulsar is given as Case 3 in Table 6. The MlOO
Sentra performance-adjusted combined MPG is 41.6; this figure
is 47 percent higher than the gasoline-fueled Pulsar.
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Table 6
Comparison of Nissan MIOO-Fueled Sentra
With Gasoline-Fueled 1988 Nissan Pulsar
Engine
Case
1
1
2
2
3
3
Vehicle
M100
1988
M100
1988
M100
1988
Sentra
Pulsar
Sentra
Pulsar
Sentra
Pulsar
CID
110
110
110
110
110
110
ETW
2875
2875
2875
2875
2875
2875
Dyno
HP
7.
7.
7.
7.
7.
7.
1
1
1
1
1
1
Gasoline Equivalent MPG Percent
N/V City
44
53
54
53
54
53
.4 36.8
.3 23.9
.4 32.6
.3 23.9
.0
.3
Hwy Comb .
53.8 42
36.7 28
46.7 37
36.7 28
41
28
.9
.3
. 7
.3
.6*
.3
Diff .
+ 52%
— —
+33%
— —
+47% '
Adjusted to account for the difference in performance with a
sensitivity value of 0.454.
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Several comparisons of gasoline equivalent fuel economy
between the MlOO Sentra and comparable gasoline vehicles have
been made here. It is difficult to do an exact comparison,
because of fundamental differences in the properties of the
fuels and the vehicles involved. The comparisons made here
reflect a "best effort" attempt at resolving some of these
differences.
The MlOO Corolla as received from Toyota (46.4 N/V, 2750
Ibs ETW, actual dynamometer horsepower 8.9 HP and final drive
ratio 3.72) was tested for acceleration performance over 5-60
MPH under the same conditions as the Nissan vehicle testing
previously described. The average acceleration time noted for
this vehicle was 10.3 seconds. We also evaluated the 5-60 MPH
acceleration performance of this vehicle at the same
dynamometer horsepower (7.1) and test weight (2,875 Ibs) as the
Nissan vehicles; no changes to the drivetrain/transaxle were
made however. Under these conditions, the 5-60 MPH
acceleration time for the MlOO Corolla increased to 10.8
seconds. We did not test a comparable Toyota gasoline vehicle
under these conditions; no attempt is made here to adjust the
gasoline equivalent fuel economy of the MlOO Corolla for
performance with respect to a specific gasoline fueled Toyota
vehicle.
VII. Highlights from Testing
1. Calculated OMHCE emissions from both test vehicles
at low mileage were well below the levels of the standard of
0.41 grams per vehicle mile established in the 1990 emissions
standards for a light-duty methanol vehicle. The MlOO Corolla
vehicle had OMHCE emissions of only 0.12 grams per mile over
the FTP.
2. Emissions of methanol, formaldehyde and HC over the
FTP from the Corolla vehicle were also low. HCHO emissions
from the Corolla were only 9.0 milligrams per mile; this level
was as low as that from the first-generation methanol lean burn
system at low mileage.[6]
3. NOx levels at low mileage from both vehicles were
below the levels of the recently proposed NOx light-duty
vehicle standard of 0.70 grams per mile over the FTP.
4. Bag 1 FTP emissions of HC, CH,OH, OMHCE and HCHO
attributable to cold start were much higher than those from Bag
3 for both vehicles. The greatest differences between cold and
hot start related emissions with respect to the level of cold
start emissions occurred with the MlOO Sentra vehicle.
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5. The combined city/highway gasoline equivalent fuel
economy of the M100 Corolla exceeded the fuel economy of a
comparable gasoline-fueled Corolla vehicle by approximately 9
percent.
6. Fuel economy test data from the M100 Sentra vehicle
were compared to selected gasoline-fueled Nissan vehicles from
recent EPA Test Car Lists. Fuel economy data from the M100
Sentra was also compared to test data from a gasoline-fueled
Pulsar vehicle equipped with a similar CA18DE base engine.
The MIOO-fueled Sentra was evaluated at the test weight
and actual dynamometer horsepower of a 1987 gasoline Pulsar
vehicle from the EPA Test Car List. An adjustment was made to
compensate for the lower measured N/V (44.4) of the M100 Sentra
compared to the higher N/V (53.6) of the Pulsar. The combined
city/highway gasoline equivalent MPG of the methanol fueled car
exceeded that of the gasoline vehicle by 39 percent.
The gasoline equivalent fuel economy of the M100 Sentra
was also compared to that of a 1988 CA18DE engine equipped
Pulsar vehicle. The M100 Sentra was evaluated at the same test
weight, actual dynamometer horsepower and nominally equivalent
N/V ratio as the gasoline Pulsar. The M100 Sentra fuel economy
was also adjusted to account for the difference in driving
performance between the two fuels.
The methanol-fueled vehicle had a combined city/highway
gasoline equivalent fuel economy approximately 47 percent
higher than the gasoline fueled comparison vehicle under these
conditions.
VIII. Future Efforts
The M100 Sentra prototype vehicle is receiving new pistons
per instructions from Nissan Motor Corporation. Nissan has
agreed to furnish a dummy catalyst for this vehicle to
facilitate baseline testing. Toyota has supplied EPA with
dummy catalysts for the two-catalyst system on the Corolla
prototype. Baseline emissions testing, using M85 and M100
fuels, has been conducted on this vehicle. This data will be
presented in a future technical report.
Advanced catalyst testing will also be conducted on both
vehicles in the future. This testing will involve the use of
both resistively heated and conventional substrate catalysts.
Preliminary evaporative emissions testing has also been
conducted on the M100 Corolla. Additional testing on this
vehicle and the M100 Sentra will be performed, and the results
included in a later technical report.
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IX. Acknowledgments
The M100 prototype vehicles evaluated in this report were
provided by the Toyota and Nissan Motor Corporations,
respectively. The Pulsar vehicle mentioned in this report also
was provided by the Nissan Motor Corporation. The author
gratefully acknowledges the support of these corporations,
without which these efforts would not be possible.
The author appreciates the efforts of the Test and
Evaluation Branch (TEB), ECTD, and particularly James Garvey
and Robert Moss, who conducted many of the driving cycle tests
and prepared the methanol and formaldehyde samples for
analysis. The author also recognizes Joseph Whitehead formerly
of the Control Technology and Applications Branch (CTAB) and
currently with the Ford Motor Company, who conducted the
performance tests on both vehicles. The efforts of Jennifer
Criss and Diane Descavish of CTAB, ECTD, for word processing
and editing support are also appreciated.
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X. References
1. "Analysis of the Economic and Environmental Effects
of Methanol as an Automotive Fuel," Special Report from the
Office of Mobile Sources, U.S. Environmental Protection Agency,
September 1989.
2. "Air Toxics Emissions and Health Risks from Motor
Vehicles," Adler, J. M. and P. M. Carey, Air and Waste
Management Association Paper No. 89-34A.6, June 1989.
3. "Development of Toyota Lean Combustion System,"
Kobayashi, N. et al., Japan Society of Automotive Engineering
Review, July 1984.
4. "Development of Methanol Lean Burn System," Katoh,
K. et al., SAE Paper 860247, February 1986.
5. "Phase I Testing of Toyota Lean Combustion System
(Methanol)," Piotrowski, G. K. and J. D. Murrell,
EPA/AA/CTAB/87-02, January 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, May 1987.
7. "Durability Testing of a Toyota LCS-M Carina,"
Piotrowski, G. K., EPA/AA/CTAB/89-03, June 1989.
8. "Methanol Vehicle Catalyst Evaluation: Phase III,"
Piotrowski, G. K., EPA/AA/CTAB/88-10, November 1988.
9. "Evaluation of Toyota LCS-M Carina: Phase II,"
Piotrowski, G. K., EPA/AA/CTAB/87-09, December 1987.
10. "Development of the Second Generation Methanol Lean
Burn System," Yasuda, A. et al. , SAE Paper 892060, September
1989.
11. "Evaluation of a Methanol-Fueled (M85) Turbocharged
Nissan Sentra," Blair, D.M., EPA/AA/CTAB/88-03, May 1988.
12. "Resistively Heated Methanol Dissociator for Engine
Cold Start Assist," Piotrowski, G. K., EPA/AA/CTAB/88-01,
February 1989.
13. "Conversion of Methanol-Fueled 16-Valve, 4-Cylinder
Engine to Operation on Gaseous 2H2/CO Fuel," Piotrowski, G.
K. and J. Martin, EPA/AA/CTAB/89-02, March 1989.
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-22-
14. "Innovative Toyota Standard Engine Equipped With
4-Valve," Kimbara, Y. et al., SAE Paper 870352, 1987.
15. Formaldehyde Measurement In Vehicle Exhaust AT MVEL,
Memorandum, Gilkey, R. L., OAR, QMS, EOD, Ann Arbor, MI, 1981.
16. "Formaldehyde Sampling From Automobile Exhaust: A
Hardware Approach," Pidgeon W., EPA/AA/TEB/88-01, July 1988.
17. "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.
18. "Emission Standards for 1990 and Later Model Year
Light-Duty Vehicles," Section 86.090-8, 40 CFR Part 86, Federal
Register, April 11, 1989.
19. "Evaluation of Resistively Heated Metal Monolith
Catalytic Converters On An M100 Neat Methanol-Fueled Vehicle,"
Piotrowski, G. K., EPA/AA/CTAB/89-09, December 1989.
20. "Evaluation of a Resistively Heated Metal Monolith
Catalytic Converter On a Gasoline-Fueled Vehicle," Piotrowski,
G. K., EPA/AA/CTAB/88-12, December 1988.
21. "Improved Control of Formaldehyde by Warmup of
Catalyst Prior to Vehicle Start," Memorandum, Piotrowski, G.
K., OAR/OMS/ECTD/CTAB, Ann Arbor, MI, 1985.
22. "Preliminary Test Results From the Nissan Sentra
Methanol-Fueled Test Vehicle," Memorandum, Hellman, Karl H.,
OAR/OMS/ECTD/CTAB, Ann Arbor, MI, July 6, 1989.
23. "M100 Nissan Sentra Versus Gasoline Pulsar
Performance," Note to Charles L. Gray, Jr., from Karl H.
Hellman, OAR/OMS/ECTD/CTAB, Ann Arbor, MI, August 4, 1989.
24. "Trends in Alternate Measures of Vehicle Fuel
Economy," SAE Paper 861426, Hellman, K. H., et al., September
1986.
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A-l
APPENDIX A
DESCRIPTION OF SECOND-GENERATION
TOYOTA LCS-M PROTOTYPE VEHICLE
Engine:
General
Compression ratio
Fuel metering
Ignition
Combustion Chamber
Bore x Stroke (mm)
Idle Speed
Spark Timing Control
Fuel
Exhaust Gas Recirculation
Vehicle:
Base vehicle
Test weight
Test HP
Transmission
Gear ratio
L4, 4A-FE engine, 1.6-liter,
dual overhead cam design
11.0:1
D-Jetronic seguential port fuel
injection
W27ESR-U Nippondenso spark plugs
Compact pent roof design
81 x 77
700 rpm, 10° BTDC ignition
timing at idle
Electronic spark advance
M100 or M85 (Toyota provided
different calibrations for each
fuel)
EGR used
1988 Corolla sedan
2,750 Ibs
8.9 hp
5-speed manual transmission,
shifting schedule 15-25-40-45
MPH
1st 3.545
2nd 1.904
3rd 1.233
4th 0.885
5th 0.725
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A-2
APPENDIX A (CONT'D)
DESCRIPTION OF SECOND-GENERATION
TOYOTA LCS-M PROTOTYPE VEHICLE
Differential Ratio
Tire Size
Catalytic Converter System
Other Modifications Made:
Engine Oil
Fuel Tank, Inlet, Delivery
Pipes
Intake Valves
Exhaust Valves
Fuel Injectors
Fuel Lines
Fuel Hose
Fuel Pump
3.722
155SR13
0.71-liter Pt:Rh (manifold
close coupled) 0.51-liter Pd
(underfloor)
Multiweight oil specially
formulated for use with methanol
Nickel/phosphorus plated
Martensitic steel with
stelliting
Austenitic steel with stelliting
Modified to accommodate greater
flowrate of methanol
Nickel plated
NBR modified
In-tank fuel pump body nickel
plated
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B-l
APPENDIX B
DESCRIPTION OF M100-FUELED
NISSAN SENTRA PROTOTYPE VEHICLE
Engine:
General CA18DE base engine, 4-cylinder,
in-line
Displacement 1.8 liters
Valvetrain 4 valves/cylinder, dual
overhead camshafts
Bore x Stroke (mm) 83 x 83.6
Compression Ratio 12.0:1
Ignition Direct ignition system
Air/Fuel Management Ultra lean burn scheme under
closed loop control
Idle Speed 650 rpm, 15° BTDC ignition
timing at idle
Fuel Metering Electronically controlled port
fuel injection
Fuel Type M100 fuel exclusively
Vehicle and Special Modifications:
Base Vehicle B12 Nissan Sentra USA model
Test Weight 2,250 Ibs suggested test weight
Test Horsepower 7.3 actual dynamometer
horsepower
Transmission 5-speed manual transmission,
shifting schedule 15-25-40-45
MPH
Engine Oil Multiweight oil specially
formulated for low friction and
use with methanol
Catalyst System 1.7-liter volume Pt:Rh catalyst
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