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OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

12) IV-B-8 

Docket Number: 

A-87-11 

Printed 11/13/2008 7:20:51 AM Sheet 12 of 232 
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SUBJECT: Measurement of HC Release With Gas Cap Renoval 

TO: 

THHU: 

Peter Hutchins, Mechanical Engineer 

Standards Development and Support Branch 

Charles L. Cray, Jr., Director 

Emission Control Technology Division 

John P. Anderson, Senior Project Manger 

Standards Development and Support Branch 

Chester J. France, Chief 

Standards Development and support Branch 

At our request, E&D hap completed two gas cap removal 

tests using the SPft modified refueling control syster. The 

average taass of hydrocarbon released as a result of car cap 

renoval at what would normally be the beginning of the hot soak 

test ^as 0.05 craos. 

Tr.o 'refuslinq svEten' and its configuration or used in 

these tests war. ac follows: 

EPA modified GM gas tank «ith "blue" rollover/vent 

valve. 

Approximately 3 ft. of 1/2" dia. hose fro^ 

roliover/vsnt valve to tee. 

Pron one branch of the tee into the canister using 

raininuro length of tubinc 

Proa the other branch of the tee to an approximately 

11 foot length of 5/16* dia. metal vapor lin* (the 

line used was that which had been employed in EPA 

presentations). 

2 1/2 liter canister modified to center top load, 

bottom vent anc? filled with Mitsubishi carbon. 

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Testing was performed as follows: 

0 Purge canister for 1 1/2 hours at a flow rate of 1 J 

_- cfm. 

• f-Place 6.0 gallons of 9.0 RVP chilled fuel in tank.f-

^ Fuel from light duty fuel dispenser used incertification testing. * 

0 Place "refueling system" in SHED (purge fan on). 

Hook up necessary eguipment to heat tank and to j 

monitor tank temperature and pressure. 

0 Heat fuel. Heat from 60°F to 84°F 'in one hour to 

represent diurnal heat build, followed immediately 

by heating from 84° to 104°F in 35 minutes to 

represent bags 1, 2 and 3 and 10 minute hot soak of 

the tailpipe test. Total time of tank heating 95 

minutes. Tank pressure and temperature were 

recorded every 5 minutes. 

° Discontinue heating at 104°, turn off purge fan, 

turn on mixing fan, seal SHED. Cap vapor line at 

end which would go to the engine (simulates closure 

of purge control valve when engine is turned off). 

° At 4 minutes after termination of heating measure HC 

level in SHED. 

0 At 5 minutes after termination of heating remove gas 

cap. Replace gas cap after venting vapors. 

0 At 6 minutes after termination of heating measure HC 

level in SHED. 

Tank pressures recorded during the tests are summarized as 

follows: 

° First test: 0.01 inch water for first 60 minutes. 

0.02 inch water for remaining 35 

minutes. 

0.02 inch water before and after gas 

cap removal. 

0.0C inch water when gas cap was off. 

° Second test: Fluctuations between 0.00 and 0.01 

ine: water for first 65 minutes. 

0.C:. inch water from 70 minute reading 

through 85 minute reading. 

O.Cli inch water for remaining 10 

minutes. 

0.01 inch water before and after gas 

cap removal. 

0.00 inch water when gas cap was off. 

Hydrocarbons released into the SHED as a result of gas cap 

removal were: 

° First test: 0.042 gram 

0 Second test: 0.056 " 
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As a result of this testing, it can be concluded that the 

fuel tank pressure of the "EPA refueling system" after an 

exhaust emission test would be on the order of 0.01 to 0.02 

inch water and that an associated gas cap removal would 

contribute^ about 0.05 grams HC to a hot soak evaporative^, 

emissions |ests. 

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