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A CARBON CANISTER WITH INTERNAL HYDROCARBON SENSORS TO MEASURE LOADING

IP.com Disclosure Number: IPCOM000240421D
Publication Date: 2015-Jan-29
Document File: 1 page(s) / 277K

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The IP.com Prior Art Database

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A CARBON CANISTER WITH INTERNAL HYDROCARBON SENSORS TO MEASURE LOADING

Vehicles sold in North America are required to capture vapors from running loss, diurnal temperature and refueling inside a carbon canister. Engine vacuum is typically used to purge the canister. As the canister is being purged, HEGO sensors determine how loaded the canister is.Another method of determining canister loading is to embed temperature sensors inside the canister. During refueling and diurnal/running loss vapor generation, the carbon inside the canister gains heat. However, the heat gain eventually subsides.During purging, the carbon cools down. The cool down also subsides over time.If a vehicle is refueled and parked for many hours, the canister temperature will equalize to ambient, yet the canister is loaded with hydrocarbon (HC). Hence the temperature gain from refueling is a transient that goes away after few hours. It becomes difficult to determine canister loading without "purging" at that point.Hence, existing methods of determining canister loading are "active". They require PCM alive, engine running and purge flow to infer canister loading either via imbedded thermocouples inside the canister or via HEGO feedback after purge is on and combustion event occurred.With HEVs, the above methods are problematic as engine run time is limited. Force activating the engine/purge flow to on to infer canister loading leads to a fuel economy penalty.

Method

Our improved method inf...