EPA-AA-TSS-PA-85-3
Evaporative Emissions
from the Fourteen Car
DOE Gasoline/Methanol Blend Fleet
(Report from Work Assignment 7, Contract 68-03-3192
with Southwest Research Institute)
Harry E. Dietzmann, Southwest Research Institute
Craig A. Harvey, EPA
July 1985
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 with may form the basis for a final EPA
decision, position or regulatory action.
Technical Support Staff
Emission Control Technology Division
Office of Mobile Sources
Office of Air and Radiation
U.S. Environmental Protection Agency
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I. INTRODUCTION
The.purpose of this work was to investigate the effect on
evaporative- emissions of mileage accumulation witn a
gasoline/methanol/cosolvent splash blend versus mileage
accumulation with the base gasoline. This test program was
carried out under Work Assignment 7 of EPA Contract 68-03-3192
with Southwest Research Institute (SwRI) in conjunction with a
one year demonstration program at SwRI sponsored by the
Department of Energy . The same vehicles (fourteen 1984 Ford
Escorts) were included in the previously completed Work
Assignment 4, which involved evaporative emission testing with
the gasoline-alcohol splash blend, the control gasoline, and a
gasoline-alcohol blend matched for FEVI* to the control
gasoline. Those tests were run after about 10,000 miles had
been accumulated on each vehicle, and the final tests reported
here were run after approximately 4,000 more miles were put on
each vehicle. A copy of the Final Data Report for Assignment 4
is included as Appendix A for reference.
Work Assignment 7 involved evaporative emission testing of
all fourteen vehicles with their original charcoal canisters,
and retesting after the canisters had been switched between the
control and blend vehicles (i.e., blend vehicles tested with
the control canisters and control vehicles tested with the
blend canisters). This was done to separate canister
differences from vehicle differences. Canisters from two
control and two blend vehicles were also weighed before and
after each segment of the SHED test to help in understanding
the load-purge cycle. The control fuel at the time of
evaporative emission testing was a winter grade (11.5 psi RVP)
unleaded fuel, but two vehicles from each group were also
tested with the summer grade control fuel (9.1 psi RVP) with
and without switched canisters. This testing provided a
comparison back to the original evaporative emissions data from
Work Assignment 4.
II. SUMMARY
Evaporative emission tests were conducted on a 14-vehicle
fleet undergoing driveability testing for DOE at SwRI. Seven
vehicles (200 series) accumulated mileage on an unleaded
control fuel, and seven vehicles (100 series) accumulated
mileage on a gasoline-alcohol blend containing four percent
methanol, two percent ethanol, and two percent t-butyl alcohol
(TBA). The results of experiments conducted with these
vehicles are summarized below:
* FEVI: Front End Volatility Index = RVP +0.13 (% evap @ 158°F)
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A. SHED evaporative emissions from the blend vehicles
at standard FTP temperatures were 32 g/test compared
to 9 g/test for the control vehicles when tested
-with the winter grade control fuel (11.5 psi RVP,
EM-620-F) . Due to the use of this higher volatility
fuel, these results can not be compared directly to
SHED tests using 9.0 psi RVP Indolene.
B. SHED evaporative emission tests conducted on four
vehicles (two of the 100 series and two of the 200
series) with the summer grade unleaded control fuel
(EM-601-F) produced evaporative emissions of 3-5
g/test. Blend and control vehicles produced
essentially equivalent SHED emissions with the
summer grade unleaded fuel (EM-601-F).
C. When canisters were randomly switched between blend
and control vehicles (i.e. blend vehicles with
control canisters and control vehicles with blend
canisters), the SHED evaporative emissions were
essentially equivalent at 30-31 g/test with
EM-620-F. Several vehicles in each group had
unusually high hot soak losses which tended to
overshadow any changes due to canister switching.
D. The diurnal contribution to the total SHED emissions
ranged from 52 to 72 percent for both vehicle groups
with EM-601-F. With the winter grade control fuel
EM-620-F, the diurnal contribution ranged from 8 to
36 percent.
E. Canister weight gain appeared to be more
vehicle-related than a function of previous fueling
history. Canisters which gained the most weight
during the hot soak also had the most breakthrough.
No differences in blend or control canisters could
be observed from canister weight gain or SHED
evaporative emissions during the canister weighing
test series.
F. In general, 36 to 42 grams of hydrocarbons/alcohols
were purged from the canister during FTP operation,
which was 4.3 - 5.5% of the purged weight of the
canister. Canister weights at the end of the hot
soak were within 11 grams (i.e., two percent) of the
weight at the start of the diurnal.
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II. DESCRIPTION OF VEHICLES AND FUELS
A. Vehicles
The fourteen vehicles tested in this Work Assignment were
obtained immediately upon completion of a DOE fleet
demonstration program which was under contract to SwRI and
administered by the Fuels and Lubricants Technology Division.
The fleet consisted exclusively of 1984 Ford Escorts, seven
accumulating mileage on the control fuel (unleaded Amoco) and
seven accumulating mileage on the blend fuel. Table 1 provides
a list of the vehicles tested during this Work Assignment and
the nominal odometer readings at the time the vehicles were
delivered for testing.
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TABLE 1. DOE TEST VEHICLES
Vehicle
No.
101
102
103
104
105
106
107
201
202
203
204
205
206
207
Mileage
Accumulation
Fuel
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Control
Control
Control
Control
Control
Control
Control
Nominal
Odometer
Reading
15,100
24,200
21,000
20,600
18,100
17,000
15,000
17,700
24,400
21,000
28,700
29,900
18,200
16,200
License
No.
261 EGK
264 EGK
260 EGK
266 EGK
265 EGK
273 EGK
259 EGK
263 EGK
267 EGK
272 EGK
271 EGK
268 EGK
262 EGK
258 EGK
Miles3
Winter
3,100
4,840
4,200
4,120
3,620
3,400
3,000
3,540
4,880
4,200
5,740
5,980
3,640
3,240
Summer
12,000
19,360
16,800
16,480
14,480
13,600
12,000
14,160
19,520
16,800
22,960
23,920
14,560
12,960
Of the mileage accumulation on the winter grade version of
the blend and control fuels, it is estimated that the
majority of the mileage accumulation was obtained during
the winter of 1983-84 (December 1983-February 1984). Only
two or three tankfuls were used at the end of the mileage
accumulation in December 1984.
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B. Fuels
Mileage accumulation was accomplished using two fuels, a
control f-ual and a blend fuel. The control fuel was an
unleaded Amoco fuel. The blend was prepared by adding methanol
(4% volume) , ethanol (2% volume) and TBA (2% volume) . The
nature of the DOE demonstration program did not provide strict
control over the RVP (or FEVI) of the test fuels, and the fuels
varied with the seasons. That is, summer grade unleaded Amoco
was used during the majority of the mileage accumulation, but
winter grade was used during December 1983, January 1984,
February 1984, and December 1984. Table 1 also summarizes the
mileage estimated to be accumulated on winter and summer grades
of gasoline. The pertinent fuel inspection data are summarized
in Table 2.
Based on obvious differences between the original control
fuel (EM-601-F) and the control fuel in use at the end of the
DOE mileage accumulation, several vehicles were tested with the
limited amount of EM-601-F remaining to provide some comparison
back to the original data from Work Assignment 4. The front
end volatility index (FEVI) of the summer grade fuel (EM-601-F)
was 12.7, compared to 15.7 for the winter grade (EM-620-F) .
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TABLE 2. FUEL INSPECTION DATA
Fuel Code
Specification ASTM
API Gravity 60 F D-287
Distillation, F D-86
IBP
10% ,
50%
90%
EP
Recovery, %
Residue, %
Loss, %
% Evaporated 158 F
RVP, psig D-323
FEVIC
EM-601-F3
59.5
87
119
207
341
409
98.0
1.0
1.0
28.0
9.1d
12.7
EM-620-F0
60.0
81
109
198
331
383
98.0
1.0
1.0
32.0
11.5
15.7
c
d
EM-601-F was a summer grade unleaded Amoco gasoline used in
the original emission testing conducted under Work
Assignment 4 of Contract 68-03-3192.
EM-620-F was a winter grade unleaded Amoco gasoline that
was being used when the final testing of the DOE vehicles
was initiated.
Front end volatility index, FEVI = RVP +0.13 (% Evap 158°F)
A different test program which used this fuel measured the
RVP to be 9.8 psi.
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III. Test Procedure
Employees used the cars in everyday driving, but used only
the mileage • accumulation fuels. Following the completion of
mileage accumulation, the fuel tanks of the seven vehicles
operating on the blend fuel were run to near empty, and a
tank'ful of the control fuel (EM-620-F) was then run through
each blend vehicle over approximately a week's time using the
same normal driving procedure as was used throughout the
program for mileage accumulation. This was done to minimize
any short term effects of the blend fuel so the testing would
show mainly any long term effects of high volatility blend use.
After all mileage accumulation and the tank of base
gasoline in the blend vehicles was used, there was a variable
length of time ranging from about one to five days before the
evaporative emission tests were run. All evaporative emissions
tests were conducted according to the Federal SHED test
procedure, except for the use of test fuels other than
Indolene. This means that following a fuel tank drain and fill
a single LA-4 preconditioning cycle was run on the dynamometer
and then within 12-36 hours the tank was drained and filled to
40% of capacity and the diurnal heat build test was run. This
was followed by cold and hot start LA-4 cycles on the
dynamometer and then the hot soak part of the SHED test was run.
IV. RESULTS
A. Original Vehicles with Original Canisters
First, all fourteen vehicles were tested with their
original canisters using EM-620-F,. These results are presented
in Table 3, and illustrate that the blend vehicles had an
average SHED emission rate of about 32 g/test compared to 9
g/test for the control vehicles. Although the test plan had an
adequate number of vehicles, no replicate tests were conducted
to investigate individual vehicle variability. Since no
repeats were run during this set of experiments, and there is a
wide vehicle-to-vehicle and test-to-test variability as shown
by this and data from the later set of experiments, the
conclusions are not as firm as they otherwise might be.
The average diurnal evaporative emissions of the blend
vehicles contributed about one-third (10 grams) to the overall
SHED emissions compared to the two-thirds (22 grams) from the
hot soak segment of the SHED test. The average diurnal
contribution to the evaporative emissions of the control
vehicles was 0.8 gram, whereas the hot soak produced an average
of 8 grams. The difference in diurnal emissions between the
blend and control vehicles was statistically significant at a
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99.5% confidence level, but the difference in hot soak losses
was not Significant at a confidence level of 95%, due to the
wide vehicle-to-vehicle scatter. The difference in total SHED
emissions*"Was significant at a 99% level.*
Initial results from these tests indicated that several
vehicles (both control and blend) had noticeably higher hot
soak losses than several apparently similar vehicles. Some
researchers feel that the hot soak losses are more related to
carburetor losses rather than canister hydrocarbon losses.
Blend vehicles which had higher-than-normal hot soak losses
were 102, 104, 105 and 107. Control vehicles which had
higher-than-normal hot soak losses were 202, 203 and 205. The
significance of these high hot soak losses is discussed in the
next section with the discussion of the effect of canister
switching.
B. Canisters Switched Between Control and Blend Vehicles
Canisters were switched randomly between control and blend
vehicles to investigate the effect on evaporative emissions.
Test results are summarized in Table 3. For the blend vehicles
equipped with the control canisters, the composite average SHED
evaporative emission rate was about 31 g/test with the 11.5 psi
RVP fuel. The diurnal segment averaged about 4 grams compared
to 27 grams produced during the hot soak. Blend vehicles 102,
103, 104 and 107 produced noticeably higher hot soak emissions
than the remaining vehicles.
When the control vehicles were tested with the blend
canisters with the same 11.5 psi RVP fuel, the SHED evaporative
emissions went from 9 g/test in the stock configuration to 30
g/test. Control vehicles 202, 203, and 205 produced higher hot
soak emissions than the remaining vehicles in that group. The
diurnal emissions were about 11 g/test while the hot soak
emissions were almost 20 g/test. To check for canister
differences as separate from vehicle differences, we can
combine these data from the switched canisters with the above
data from the original canister/vehicle tests. The fourteen
tests with the 100 series canisters can be compared to the
fourteen tests with the 200 series canisters. This comparison
shows the diurnal emissions from the blend canisters (100
series average 10.4 grams) to be greater than the gasoline
The statistical test used was the T test for independent
groups of data.
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canisters (200 series, average 2.3 grams) at a 99.5% confidence
level. Due to the wide scatter in hot soak data, there is no
significant difference in hot soak or total emissions at a 95%
confidence level. However, if the higher hot soak tests are
omitted from the data, the blend canisters average 6.5 grams
per hot soak compared to 3.3 grams for the gasoline canisters,
and the difference is significant at a 99% level. In this case
the total SHED emissions average 15.6 grams for the blend
canisters versus 5.6 grams for the gasoline canisters, and the
difference is significant at a 99.5% level.
It is interesting to note that in tests with the canisters
from the blend vehicles the hot soak emissions were about twice
the diurnal emissions. For those tests with control canisters,
the hot soak was 7-11 times greater than the diurnal emission
rate. Table 4 summarizes the diurnal contribution to the
overall SHED emissions. In general, the diurnal segment of the
SHED accounted for 50-75 percent of the composite SHED emission
rate when the blend and control vehicles were tested with
EM-601-F. When these same vehicles were tested with the winter
grade gasoline, the diurnal segment accounted for an average of
8 to 12 percent of the SHED emissions for the control canisters
and 31 to 36 percent of the SHED emissions for the blend
canisters.
Based on the data presented in Table 3, it appears that
the higher hot soak losses attributed to vehicles 102, 104, 105
and 107 were also observed on three of these vehicles when the
canisters were switched and these vehicles were tested with the
control canisters (vehicles 102, 104 and 107). A similar trend
was observed for the control vehicles where 202, 203 and 205
produced noticeably higher hot soak emissions with both the
blend and control canisters. Since the hot soak emissions
accounted for the majority of the SHED emissions when using
EM-620-F and since it appears that the vehicle may influence
hot soak emissions more than the canister, it is very difficult
to determine the effect of canister switching.
Although these data indicate some increase in evaporative
emissions from the blend canisters (100 series) relative to the
gasoline canisters (200 series), when tested with the 11.5 psi
RVP gasoline, this can not simply be attributed to the presence
of alcohol in the mileage accumulation fuel. The other major
difference between the mileage accumulation fuels was their
volatility, since the blend fuel was a splash blend with no
attempt at volatility matching. Therefore it is uncertain from
these data alone whether mileage accumulation on an alcohol
blend fuel with a matched volatility to a base gasoline would
show any difference in evaporative emissions.
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TABLE 3
SUMMARY OF SHED EVAPORATIVE EMISSIONS RESULTS
(11.5 psi RVP TEST FUEL)
SHED Evaporative Emissions, g
Vehicle3
101
102
103
104
105
106
107
201
202
203
204
205
206
207
101
102
103
104
105
106
107
201
202
203
204
205
206
207
Fuel
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
Canisterb
101
102
103
104
105
106
107
Avg.
S.D.
201
202
203
204
205
206
207
Avg .
S.D.
202
201
207
204
206
205
203
Avg.
S.D.
102
101
107
104
106
105
103
Avg.
S.D.
Diurnal
6.28
4.92
14.50
10.22
16.13
3.77
13.20
9.86
4.94
0.50
0.32
0.44
0.33
2.07
0.37
1.31
0.76
0.67
1.69
3.85
- 6.80
2.04
2.17
10.26
0.34
3.88
3.48
10.20
17.23
4.78
11.37
15.26
6.85
10.38
10.87
4.36
Hot soak
7.13
37.44C
7.22
57.82C
12.25C
5.38
24.68C
21.70
19.74
2.67
10.98°
12.35C
2.63
20.02C
2.20
7.90
0739
6.61
1.25
58.44C
52.56C
47.84C
3.77
2.40
23.97C
27.18
25.47
9.37
43.20C
39.90^
5.03
27.53C
3.40
8.27
19.53
17.03
Total
13.41
42.36
21.72
68.04
28.38
9.15
37.88
31.56
20.11
3.17
11.30
12.79
2.96
22.03
2.57
9.21
9.15
7.08
2.94
62.29
59.36
49.90
5.94
12.66
24.31
31.06
25.62
19.57
60.43
44.68
16.40
42.79
10.25
18.65
30.40
18.78
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101
102
201
202
101
102
201
202
Table 3 (continued)
SUMMARY OF SHED EVAPORATIVE EMISSIONS RESULTS
(9.1 psi RVP TEST FUEL)
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-601-F
202
201
Avg.
S.D.
102
101
Avg.
S.D.
101
102
Avg.
S.D.
201
202
Avg.
S.D,
1.68
2.24
1.96
0.40
0.43
4.45
2.44
2.84
1.09
4.32
2.71
2.28
2.77
6.57
4.67
2.68
1.43
5.79
3,
3,
61
08
6.30
2.29
47TO
2.84
0.06
a) 100 Series Vehicles accumulated mileage on alcohol blend
fuel containing 4% methanol, 2% ethanol and 2% tertiary
butyl alcohol added to the baseline commercial unleaded
Amoco gasoline. 200 Series Vehicles accumulated mileage on
commercial unleaded Amoco gasoline.
b) The "canister" column indicates that tests on the 11.5 RVP
fuel were first run with the vehicle's original canisters
and then canisters were switched between the two sets of
vehicles. Then testing was done with the 9.1 RVP fuel,
first with the canisters switched and then with them back on
their original vehicles.
c) Higher hot soak test results which may be related more to
carburetor factors than canister factors.
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C. Comparison of Vehicles to Original Tests
Several SHED tests were conducted with vehicles operating
on EM-60r-"F- to provide a comparison back to the original
baseline. Only two vehicles of each group were included in
this study. These vehicles were tested with their original
canisters and with the canisters switched. These results are
presented in Table 5, and are summarized and compared to the
original tests conducted in Work Assignment 4. The difference
between blend and control SHED evaporative emissions was not as
apparent as it was during the original tests. Switching
canisters did not have any effect on SHED emissions. It should
be noted that only two vehicles, rather than the original
seven, were used in these tests. The intent of these tests was
to establish that the vehicles had not shifted significantly
since the original tests in Work Assignment 4. The blend
vehicles were down slightly and control vehicles were up
somewhat, but in neither case was a major shift observed.
D. Canister Weighing
Two blend vehicles (101 and 102) and two control vehicles
(201 and 202) were selected for additional experiments that
included canister weighing during different segments of the
SHED test. The purpose of these tests was to investigate the
relationship between the hydrocarbons adsorbed on the charcoal
and the hydrocarbons measured in the SHED. The hydrocarbons
adsorbed onto the carbon were determined by canister weighing.
These plus the hydrocarbons measured in the SHED test (i.e. the
evaporative emissions) would be the total vapor generated.
These results are presented in Table 6 for vehicles 101, 102,
201 and 202 with their original canisters. In reviewing these
data, it is important to recall that two of these vehicles (202
and 102) were identified as possibly having higher soak losses
due to carburetor losses rather than canister breakthrough
losses. The possibility is also apparent with these two
vehicles during these tests. For example, vehicle 101 produced
2 g/hot soak while vehicle 102 had about 20 g/hot soak. A
similar trend was observed with vehicle 201, which produced 7
g/hot soak as compared to 18 g/hot soak for vehicle 202. Two
of the three hot soak tests for vehicle 201 were 1 g/hot soak
but the third test had higher (about 17 grams) hot soak losses.
Canister weight gain appeared to be more related to the
specific vehicles than to the fuel used for mileage
accumulation. For example, vehicles 101 and 201 had
essentially equivalent canister weight gain (36 to 38 grams),
although one was a blend vehicle and one was a control
vehicle. Vehicles 102 and 202 were identified as vehicles with
high hot soak losses. This was also observed in these
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experiments where canister weight gain for these two vehicles
was 45 to 50 grams, with the majority of the weight gain being
observed in the hot soak segment of the test.
Table 7 summarizes the actual canister weights that were
observed during these experiments. The canister weights before
diurnal testing were 800 + 15 grams for canisters from both
blend and control vehicles. The diurnal canister weight gain
was 16+6 grams with control and blend vehicles being
essentially equivalent. After the vehicles had completed the
FTP cycle, canisters were re-weighed and FTP losses during the
canister purge were determined. These data are also presented
in Table 7 and illustrate that the canisters generally lost 33
to 42 grams during the FTP purge. No difference between
canisters from blend and control was observed for losses during
the FTP purge. The after-hot soak canister weights were
generally within 11 grams of the before-diurnal canister weight.
V. QUALITY ASSURANCE
The areas requiring quality assurance on this work
assignment are SHED calibration and retention check, HC FID
calibration, and balance for canister weighing. SHED
calibrations, SHED retention checks and HC FID calibrations
were performed using procedures and equipment specified in the
Federal Register. Records of these calibrations are available
to confirm that the SHED and FID-related calibrations were
valid during the period when emission testing was conducted.
The balance used for weighing canisters was calibrated
prior to each individual test using a 2 Ib and a 1 Ib weight.
These data were included on the^ canister-weighing data sheet.
The balance accuracy for reference weights was 0.04 percent or
better for both the 1 Ib and 2 Ib weights, for all tests
requiring canister weighing (Table 8).
No problems were encountered with operation or calibration
for the SHED, FID, or balance, and all data should be
considered valid from a strictly analytical standpoint.
However, it must be recognized that vehicle repeatability in
the SHED test, particularly with vehicles operating on a
relatively high volatility fuel, is not as good as a typical
new certification vehicle. Since no replicate tests were
conducted and several vehicles (blend and control) were
identified as having higher than normal hot soak emissions, it
will be difficult to draw any conclusions as to the effect of
canister switching.
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VI. RECOMMENDATIONS
Investigation of evaporative emissions from vehicle fleets
provides valuable information for typical evaporative
emissions. However, when using these fleets to look for small
changes due to fuel, canister, and other items, it is quite
conceivable that the variability of the vehicles and test
procedures will overshadow any differences due to canister
switching. If it is desirable to pursue additional research
along these lines, SwRI has several suggestions that might be
of interest.
1. Vehicle fleets are expensive to operate and it is
not always possible to "piggy-back" emissions
testing on a fleet test that is using the alcohol
blend of interest. Previous work assignments have
used synthetic blends to simulate gasoline and blend
vapors in loading mini-canisters. Although these
studies have provided useful information on loading
and purging characteristics, it is difficult to
relate these data to equivalent vehicle evaporative
emissions. The desirable approach would be to have
a bench scale system that would load and purge
full-scale canisters using actual gasoline and
blend vapors. The system could be used on a
24-hour basis to simulate mileage accumulation on
many canisters simultaneously. It would also allow
flexibility for testing canister capacity, as well
as evaporative emission testing of the canisters on
slave vehicles.
Another advantage of -this type of system is that
various fuel blend formulations could be evaluated
using various combinations of alcohols, co-solvents
and gasoline. This system would allow investigation
of azeotrope formation with alcohol-gasoline blends.
2. Using the aforementioned evaporative emission
generator, it would be possible to conduct
experiments that would provide a better
understanding of azeotrope formation with various
alcohol blend combinations. Vapor composition could
be monitored for methanol, co-solvent, and detailed
hydrocarbons to establish the relationship between
vapor composition in a typical gas tank and those
vapors adsorbed during normal and hot vehicle purges.
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TABLE 4. DIURNAL CONTRIBUTION TO OVERALL SHED EMISSIONS FROM
BLEND AND CONTROL VEHICLES WITH VARIOUS CANISTER COMBINATIONS
Vehicle
Group
Blend
Control
Blend
Control
Blend
Control
Blend
Control
Blend
Control
Fuel
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-601-F
EM-620-F
EM-620-F
EM-620-F
EM-620-F
Canister
Blend3
Control3
Blend
Control
Control0
Blendb
Blend
Control
Control
s Blend
TTtT\* /"*«.w^**-^j'«l4-
jn.i-*LJ jjui*t.»«j*v»»«-*r
% Diurnal
67
52
72
65
42
68
31
8
12
36
ca_m-7i Q7
aWor< Assignment. •*, c.m i_v..».*.,-— ^_ ,_
bOnly four vehicles/canisters: 101, 102, 201, 202
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-17-
TABLE 5. COMPARISON OF SHED EVAPORATIVE EMISSIONS FROM BLEND
AND CONTROL VEHICLES WITH FUEL EM-601-F (9.1 psi RVP)
b
SHED Evaporative Emissions
Vehicle
Blend3
Control3
Blend
Control
Blend
Control
Canister
Blend
Control
Blend
Control
Control
Blend
Diurnal
3.70
1.31
3.10
2.07
1.96
2.44
Hot Soak
1.85
1.19
1.20
1.10
2.71
1.17
Total
5.55
2.50
4.30
3.17
4.67
3.61
aWork Assignment 4, EPA Contract 68-03-3192.
^Numbers given are average of tests on two vehicles
(101 and 102 with the blend or 201 and 202 with
the control fuel used for mileage accumulation.)
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-18-
TABLE 6. SHED EVAPORATIVE EMISSION RATES AND CANISTER WEIGHT GAIN,
SUMVIARY FOR VEHICLES, 101, 102, 201 AND 202 WITH EM-620-F
Vehicle
101
SHED Evaporative Emissions,g Canister Weight Gain,g
102
201
202
Run
1
2
3
Avg
S.D.
1
2
3
Avg
S.D.
1
2
3
Avg
S.D.
1
2
3
Avg
S.D.
Diurnal
8.63
11.84
7.51
9.33
2.25
10.76
12.72
13.18
12.22
1.29
7.38
7.99
6.54
7.30
0.73
10.41
6.38
15.67
10.82
4.66
Hot Soak
2.14
1.27
1.45
1T62
0.46
32.90
11.92
17.10
20.64
10.93
1.26
1.05
17.41
6.57
9.39
6.39
16.94
30.06
17.80
11.86
Total
10.77
13.11
8.96
10.95
2.08
43.66
24.60
30.30
32.85
9.78
8.64
9.04
23.95
13.88
8.73
16.80
>23.32
45.73
28.62
15.17
Diurnal
21.2
20.9
22.9
21.7
1.1
18.4
18.2
17.5
IsTo
0.5
17.3
17.5
21.3
18.7
2.3
15.0
18.8
10.0
14.6
4.4
Hot Soak
16.7
14.2
13.0
14.6
1.9
34.0
29.9
31.3
31.7
2.1
22.9
15.7
18.2
18.9
3.7
28.9
31.6
32.3
3079
1.8
Total
37.9
35.1
35.9
36.3
1.4
52.4
48.1
48.8
49.8
2.3
40.2
33.2
39.5
37.6
3.9
43.9
50.4
42.3
45.5
4.3
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TABLE 7. SUMMARY OF CANISTER WEIGHTS DURING SHED TESTING ON VEHICLES
101, 102, 201 AND 202 WITH EM-620-F
Canister Weight,
Before
Diurnal
814.6
816.4
807.2
812.7
4.9
812.8
814.9
815.4
814.4
1.4
787.4
788.2
781.2
785.6
3.8
793.0
790.0
802.9
795.3
6.8
After
Diurnal
835.8
837.3
830.1
834.4
3.8
831.2
833.1
832.9
832.4
1.0
804.7
805.7
802.5
804.3
1.6
808.0
808.8
812.9
809.9
2.6
Diurnal
Gain
21.2
20.9
22.9
21.7
1.1
18.4
18.2
17.5
18.0
0.5
17.3
17.5
21.3
18.7
2.3
15.0
18.8
10.0
14.6
4.4
Before
Hot Soak
793.7
793.6
789,9
792.4
2.2
795.2
794.4
792.4
794.0
1.4
767.9
767.9
766.8
767.5
0.6
770.0
775.4
774.8
773.4
3.0
g
After
Hot Soak
809.0
807.8
802.9
806.6
3.2
829.2
824.3
823.7
825.7
3.0
790.8
783.6
785.0
786.5
3.8
798.9
807.0
807.1
804.3
4.7
Hot Soak
Gain
16.7
14.2
13.0
14.6
1.9
34.0
29.9
31.3
31.7
2.1
22.9
15.7
18.2
18.9
3.7
28.9
31.6
32.3
30.9
1.8
FTP
a
Losses
42.1
43.7
40.2
42.0
1.8
36.0
38.7
40.5
38.4
2.3
36.8
37.8
35.7
36.8
1.1
38.0
33.4
38.1
36.5
2.7
b
Canister
+5.6
+8.6
+4.3
+6.1
2.2
-16.4
-9.4
-8.3
-11.3
4.4
-3.4
+4.6
-3.8
-0.9
4.7
-5.9
-17.0
-4.2
-9.0
7.0
Vehicle Run
101 1
2
3
Avg
S.D.
102 1
2
3
Avg
S.D.
201 1
2
3_
Avg
S.D.
202 1
2
3
Avg
S.D.
aFTP losses = (weight of canister after diurnal)- (weight of canister before SHED hot soak)
bCanister = (weight of canister before diurnal)-(weight of canister after SHED hot soak)
10
i
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-20-
TAPLE 8. SUWIARY OF REFERENCE WEIGHT CHECKS ON BALANCE
USED FOR CANISTER WEIGHING
2 Ib Weight(907.4g)
1 Ib Weight(453.6g)
Vehicle
101
102
201
202
Run
1
2
3
Avg
1
2
3
Avg
1
2
3
Avg
1
2
3
Avg
Actual
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
907.4
Observed
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
907.6
% change
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
Actual
453.6
453.6
453.6
453.6
453.6
453.6
453.6
453T6
453.6
453.6
453.6
453.6
453.6
453.6
453.6
453.6
Observed
453.8
453.8
453.8
453.8
453.8
453.8
453.8
453^8
453.8
453.8
453.8
453.6
453.8
453.8
453.8
453.8
% charge
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
% change defined as
(Observed-Actual) x 100%
Actual
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