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AN EVAP CARBON CANISTER WORKING CAPACITY DIAGNOSTIC

IP.com Disclosure Number: IPCOM000243426D
Publication Date: 2015-Sep-21
Document File: 1 page(s) / 234K

Publishing Venue

The IP.com Prior Art Database

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AN EVAP CARBON CANISTER WORKING CAPACITY DIAGNOSTIC

Vehicles sold in North America must adsorb refueling, running loss and diurnal vapors in a carbon canister. Carbon has a property of easily absorbing hydrocarbon (HC).During engine running conditions, the canister is purged of HC by allowing fresh air to enter the canister and dislodge HC. The Canister Purge Valve (CPV) opens and engine vacuum is used to pull in fresh air across the canister to combust the HC in the cylinders.Canisters age over time and can become contaminated, limiting the ability to adsorb HC. Water ingestion or liquid fuel carryover can degrade the carbon bed.The telltale that the canister is still adsorbing HC is the exothermic chemical reaction phase it goes through (gains heat) during refueling. The telltale that the canister is desorbing HC is the endothermic reaction that occurs during purging. Canister temperature can reach freezing point at times, especially at the purge port of the canister. Currently there is no diagnostic or monitoring the canister ability to adsorb and desorb HC. The canister is assumed to function properly over 100,000 miles. Future OBD diagnostics may include functional integrity checks of carbon canisters, i.e., canister is able to adsorb and desorb HC. Currently there is no diagnostic for the canister working capacity.

Method

This method performs diagnostics on the evap canister using an externally mounted strain gage bonded on the canister housing or molde...