EPA-AA-TEB-89-03
Low-Altitude and Low-Temperature Exhaust Emissions
Tests of Four Vehicles
on
Oxygenated Gasoline Blends and Gasoline Fuels
by
Edward Anthony Earth
May 1989
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.
Test and Evaluation Branch
Emission Control Technology Division
Office of Mobile Sources
U.S. Environmental Protection Agency
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Background
The Coordinating Research Council (CRC) addresses
technical issues of mutual interest to both the automotive and
petroleum industries. The group initiated CRC Project No.
CM-129-87, Wintertime Exhaust Emissions, to study the effect of
altitude and the use of oxygenated gasoline blends on vehicle
exhaust emissions at 75°F and at low temperature . Sixteen
vehicles representing three different control technologies were
tested: six vehicles with closed-loop, three-way catalyst
control systems and adaptive learning devices representing the
most advanced emission control systems; six closed-loop,
three-way catalyst vehicles; and four open-loop carbureted
vehicles representing older control technology. The test
temperatures were 75°F, 50°F, and 35°F.
To support this effort, EPA provided the four open-loop
carbureted vehicles and conducted the low-altitude tests on
these vehicles at the EPA Motor Vehicle Emission Laboratory
(MVEL) in Ann Arbor, MI. CRC selected the twelve closed-loop
vehicles to be close to or meet the emission standards rather
than to represent typical in-use vehicle emissions. The
low-altitude tests on the twelve closed-loop vehicles were
conducted at the National Institute for Petroleum and Energy
Research (NIPER) in Bartlesville, Oklahoma. The high-altitude
testing of all sixteen vehicles was conducted at the
Environmental Testing Corporation (ETC) laboratory in Denver,
Colorado.
Only the EPA tests of the four open-loop carbureted
vehicles are given here. This report is essentially a data
report of these tests without detailed analysis of the
effects. The ETC and NIPER tests are covered in CRC reports
for project CM-129-87.
Discussion
Each of the four vehicles had single FTP tests at 35°F and
50°F for each of the three CRC fuels (six tests total per
vehicle). At 75°F there were single FTP tests using each of
the four EPA fuels. The tests were conducted in the EPA
Environmental Test Facility using the large (48 inch) single
roll electric chassis dynamometer. The EPA lab altitude is
894.6 Ft. A summary of the exceptions to the standard FTP is
given below:
FTP tests only, no evaporative emissions tests or
heat builds.
EPA did not have the capability to store fuel at
fuel temperatures lower than 60°F. Also, vehicle
preps and soaks were limited to a lower temperature
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of 50°F. Therefore, EPA-" decided to chill the CRC
fuels to only 50°F in the fuel dispensing cart.
Thus, when transferring fuel to the refrigerated
fuel dispensing cart, some light ends may have been
lost and the fuel may not have been totally
representative of a similar fuel which was handled
at 30-35°F.
CRC conditioning cycle was used after changing fuel
type (CRC conditioning cycle is given at end of
report).
CRC conditioning cycle served as vehicle prep.
Vehicles were tested with prep fuel. Therefore,
there was no fuel drain and refill to 40 percent
level with chilled fuel immediately prior to the FTP
tests.
Vehicle prep - at 75°F for 75°F tests
at 50°F for 35°F and 50°F tests
Vehicle soaks - at 75°F for 75°F tests
at 50°F for 35°F and 50°F tests
Note: For 35°F tests, vehicle was force
cooled from 50°F soak temperature to
35°F temperature prior to testing. Test
was started after engine oil stabilized
at 35°F.
Only single tests were conducted for each vehicle/fuel
type/temperature combination. To minimize test variability,•
all tests, including those at 75°F, were conducted in the EPA
Environmental Test Cell.
Fuel/Temperature FTP Test Matrix for Each Vehicle
Temperature
Fuels 35°F 50°F 75°F
CRC Fuels
Gasoline, 12.8 psi RVP X X
Howell batch 129-1
Gasohol, 13.5 psi RVP
10% ethanol by Vol. X X
Howell batch 129-3
MTBE gasoline, 13.5 psi RVP
10.8% MTBE by Vol. X X
Howell batch 129-4
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Fuel/Temperature FTP Test Matrix-'for Each Vehicle cont'd
Temperature
Fuels 35°F 50°F 75°F
EPA Emission Factors Fuels
Gasoline, 11.9 psi RVP X
Gasohol, 10.0 psi RVP X
9. 6% ethanol by Vol
MTBE gasoline, 9.3 psi RVP,
14.3% MTBE by Vol. X
Certification 9.1 psi RVP gasoline X
NOTE: CRC/Howell would have provided EPA the fuels for 75°F
testing. However, due to limited EPA on-site storage for fuels
in barrels, EPA elected to use its own fuels from bulk storage
for these 75°F reference blends. At the time testing was
orginally scheduled, EPA gasohol was about 11.5 psi RVP and 10%
ethanol and the EPA MTBE was about 12.2 psi RVP and 11% MTBE.
These lower RVP reference fuels were to be used for the 75°F
testing since they were representative of RVP's at 75°F and the
use of 13.5-12.8 RVP winter fuels at 75°F occurs rarely during
the winter months. Furthermore, in the few cases this does
occur, ambient CO levels are usually low.
However, the start of testing was delayed six months to
support several higher priority programs. In the interim EPA
changed the specifications for the gasohol and MTBE fuels to
the specifications in the table to obtain a better test matrix
for emission factors testing. Therefore, the EPA fuels do not
match the CRC high altitude test fuels at 75°F as well as
originally intended. CRC was informed of the changes in these
fuels during the test program.
The Reid Vapor Pressures (RVP) and blends for the three CRC
fuels were preliminary values provided by CRC and Howell
Hydrocarbons Inc. The RVP values for the EPA fuels represent
the average of 8 to 14 replicate analyses of the fuel batch at
the time that the fuel was used for this program.
The vehicles are described at the end of this report. The
dynamometer inertia weights and horsepower settings used were
the same used at ETC.
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Results
The composite FTP test results are tabulated at the end of
this report. Because the tests were processed using the same
software program used to process tests at standard
temperatures, there are several cautions that apply to these
data.
1. Below 66°F, the software program did not calculate
the NOx humidity correction factor, but used 1.0 as
the correction factor.
2. The calculations for HC and mpg were done using the
properties of Indolene (the standard reference
gasoline). They were not corrected for
carbon-hydrogen ratio, FID response, oxygen content
or the density of each fuel.
3. The dry bulb temperatures given in the tabulation
were the average temperature observed during the FTP.
To facilitate the testing process, the vehicles were first
tested at 75°F using the EPA fuels. Then, to minimize fuel
requirements, all eight tests on each CRC fuel were conducted
before using the next CRC fuel.
Originally, 40 tests were scheduled with no repeats. After
reviewing the data from the EPA test fuels, it was felt four of
the tests should be rerun. Only the reruns are reported here.
The Citation test at 50°F on 12.8 RVP gasoline and the Pinto
test at 35°F on 13.5 RVP gasohol were not rerun due to a lack
of the CRC fuels.
Conclusions:
For this data report, there was no attempt to analyze the
results or compare them to the corresponding tests at high
altitude. Furthermore, vehicles within a given technology
group vary in their response to fuel oxygen content. Thus, a
sample of four open-loop oxidation catalyst vehicles may not
give data with much statistical significance (or representative
of the fleet as a whole). In other words, due to the size of
this test program relative to the large emissions data base
currently available at FTP temperatures, the data will probably
be used by EPA only as a rough indicator of the relative
effects of oxygenate at low temperature and/or high altitude
compared to the effects at FTP temperature and low altitude.
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Test Sequence
Drain vehicle fuel tank and fuel lines including any fuel tank
return lines.
Add three gallons of new test fuel.
Start vehicle and idle for five minutes.
Drain vehicle fuel tank and fuel lines including any fuel tank
return lines.
40 percent fill with new test fuel at 50°F or lower.
Put vehicle on dyno. Vehicle may be driven to dyno but not
more than two minutes.
Vehicle may not be used to set dyno horsepower.
NOTE: For 35°F and 50°F tests, the prep must be done at 50°F.
CRC Prep/Vehicle Fuel Conditioning
LA-4
Key-off five minute soak,
Start and one minute idle
Key-off, one minute soak
Start and one minute idle
Key-off, one minute soak
LA-4
12 to 18 hour soak
FTP
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MANU-
FACTURER
MODEL
EPA
LICENSES
V.I.N.
MODEL
YEAR
ENGINE
INERTIA
WEIGHT
H.P.@ 50
TRANS-
MISSION
TIRES
Ply.
VOLARE
EPA Test Vehicles
Chev. Olds.
CITATION CUTLASS
Ford
PINTO
EPA-1170 EPA-1172 EPA-1176 EPA-1177
HL29C9B217336 1X687AQ139507 3R47A9M5232BO 9T11Y186165
1979 1980
225 CID/6 CYL. 2.8L/V-6
3500
11.3
AUTO
P195/75 R14
3000
7.3
AUTO
P185/80 R13
1979
3.8L/V-6
3500
12.2
AUTO
P195/75 R14
1979
2.3L/I-4
2750
9.7
AUTO
P175/80 D13
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CRC/EPA LOW ALTITUDE TESTING
DATE
TEST
TEMP
FUEL
1980 Chevrolet Citation EPA 1172
1/1 1/89
1/18/89
1/1 9/89
1/20/89
2/10/89
2/15/89
2/17/89
2/24/89
3/1/89
3/3/89
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
73.3
74.9
74.3
72.6
51.0
35.7
36.0
51.7
35.2
51.5
9.0 INDO/EPA
GASOHOL/EPA
11.5 UNLD/EPA
14.3% MTBE/EPA
13.5 RVP MTBE
13.5 RVP MTBE
12.8 RVP
12.8 RVP
13.5 RVP GASO
13.5 RVP GASO
1979 Ford Pinto EPA 1177
3/8/89
1/27/89
3/9/89
2/1/89
2/14/89
2/15/89
2/17/89
2/21/89
3/2/89
3/3/89
2198
1454
2199
1456
1457
1458
1459
1460
1461
2197
76.3
74.9
74.8
74.8
51.0
34.1
35.4
51.8
36.1
50.4
9.0 INDO/EPA
GASOHOL/EPA
11.5 UNLD/EPA
14.3% MTBE/EPA
13.5 RVP MTBE
13.5 RVP MTBE
12.8 RVP
12.8 RVP
13.5 RVP GASO
13.5 RVP GASO
HCftp
0.51
0.50
0.58
0.49
1.66
2.19
2.07
CO ftp
3.68
2.66
3.88
2.51
17.77
22.65
24.45
NOx ftp
0.96
0.92
0.86
0.94
1.04
1.03
1.04
CO2 ftp
453.8
441.2
435.1
441.8
460.6
463.0
475.7
This test requires further analysis.
1.94
1.44
1.78
1.54
1.45
1.50
2.10
2.12
1.91
2.00
20.02
14.85
18.52
14.29
16.81
14.15
24.38
24.85
24.29
30.80
1.07
1.06
1.62
1.47
1.75
1.51
2.32
3.32
3.06
2.53
473.5
462.5
386.5
389.9
378.1
384.1
397.0
405.4
409.6
378.5
This test requires further analysis.
2.05
27.24
2.88
413.0
NOTE: Temperatures below 66 degrees use NOx factor of 1.0 to calculate NOx.
MPG*
19.22
19.85
20.02
19.82
17.94
17.54
17.02
17.36
18.07
21.08
21.25
21.68
21.58
20.06
19.67
19.52
20.49
19.18
NOTE: These calculations have been carried out using the properties of Indolene. They have
not been corrected for carbon-hydrogen ratio, etc. associated with the oxygenated fuels
or the densities of each fuel.
TEST RESULTS
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CRC/EPA LOW ALTITUDE TESTING
DATE
TEST
TEMP
FUEL
1979 Oldsmobile Cutlass EPA 11 76
3/8/89
3/9/89
3/10/89
2/2/89
2/9/89
2/14/89
2/16/89
2/17/89
3/2/89
3/3/89
2193
2194
2195
1446
1447
1448
1449
1450
1451
2192
75.5
74.5
75.0
75.9
37.0
49.6
49.8
35.3
35.7
52.4
9.0 INDO/EPA
11.5 UNLD/EPA
GASOHOL/EPA
14.3% MTBE/EPA
13.5 RVP MTBE
13.5 RVP MTBE
12.8 RVP
12.8 RVP
13.5 RVP GASO
13.5 RVP GASO
1979 Plymouth Volare EPA 1170
1/13/89
1/18/89
1/19/89
1/25/89
2/9/89
2/14/89
2/17/89
2/27/89
3/2/89
3/3/89
1422
1423
1424
1425
1426
1427
1428
1430
1431
2196
73.0
75.5
74.1
72.2
35.6
50.9
36.6
50.8
36.4
50.9
9.0 INDO/EPA
GASOHOL/EPA
11.5 UNLD/EPA
14.3% MTBE/EPA
13.5 RVP MTBE
13.5 RVP MTBE
12.8 RVP
12.8 RVP
13.5 RVP GASO
13.5 RVP GASO
HCftp
0.53
0.47
0.47
0.50
1.04
1.01
1.01
1.66
1.58
0.99
0.68
0.82
.-
CO ftp
4.86
4.28
2.47
4.96
14.10
12.55
10.97
19.42
19.80
12.42
9.67
8.83
NOx ftp
1.47
1.50
1.26
1.34
1.67
1.52
1.25
1.79
1.67
1.46
1.32
1.04
CO2ttp
439.0
430.3
442.1
449.3
449.4
439.9
414.9
447.2
444.3
436.1
457.7
444.5
This test reguires further analysis.
0.51
1.40
0.98
1.50
1.39
1.20
1.50
5.71
20.42
17.58
22.19
22.43
19.81
12.17
1.35
1.63
1.67
1.81
1.43
1.85
1.81
442.7
474.2
491.3
493.1
474.1
493.6
487.0
NOTE: Temperatures below 66 degrees use NOx factor of 1 .0 to calculate NOx.
I
MPG*
19.77
20.24
19.82
19.34
18.69
19.16
20.36
18.37
18.47
19.34
18.65
19.26
19.55
17.37
17.00
16.65
17.26
16.77
17.36
NOTE: These calculations have been carried out using the properties of Indolene. They have
not been corrected for carbon-hvdroqen ratio, etc. associated with the oxygenated fuels
or the densities of each fuel.
TEST RESULTS
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