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AN ONBOARD CANISTER AGING SCHEME FOR SHED TESTING FOR HEV VEHICLES

IP.com Disclosure Number: IPCOM000238398D
Publication Date: 2014-Aug-22
Document File: 1 page(s) / 249K

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The IP.com Prior Art Database

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AN ONBOARD CANISTER AGING SCHEME FOR SHED TESTING FOR HEV VEHICLES

Vehicles sold in North America are required to adsorb refueling, diurnal and running loss vapors into a carbon canister. Strict Evap emission standards must be met for vehicles to be certified. Once the canister is loaded with vapors, engine running manifold vacuum is used to clean out the canister in a process known as "purging".Vehicles must also pass SHED emission testing before they are certified by the EPA. SHED testing is typically a 2 or 3 day diurnal test and total vehicle hydrocarbon (HC) emissions must not exceed certain limits. Green canisters must be aged before SHED development testing commences. For calibration sign off, the canister must be aged. The aging helps establish the "heel" of the canister. The heel is the region in the canister where HC become permanently bonded to the activated carbon. The canister is typically aged by removing it from the vehicle and loading it on a test stand until 2 grams HC breakthrough is reached as measured by a HC sensor. The canister is weighed on a scale to determine the amount of HC loading. At that point, the canister is purged from HC. The loading/purging is repeated 23 times. It takes up to two days to perform this aging that simulated 4000 miles of drive. Aging cycle is referred to as "4K" aging. The 4K aging cycle is intrusive as it requires the canister to be removed from the vehicle and loaded on a test stand. Anytime the canister is re...