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VEHICLE AMBIENT AIR QUALITY HYDROCARBON LEVEL MONITORING

IP.com Disclosure Number: IPCOM000249796D
Publication Date: 2017-Apr-05
Document File: 1 page(s) / 203K

Publishing Venue

The IP.com Prior Art Database

Abstract

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VEHICLE AMBIENT AIR QUALITY HYDROCARBON LEVEL MONITORING

Vehicles sold in North America are required to adsorb diurnal, running loss and refueling vapors inside a

carbon canister. Hydrocarbon (HC) vapors contribute to smog and it is undesirable to emit HC into the

atmosphere, as smog may contribute to health issues. The carbon canister is typically cleaned or purged

using engine vacuum during combustion. Some Evap systems use thermocouple(s) embedded in the

canister’s carbon bed to monitor canister loading state and desorption of hydrocarbons. Canisters

typically gain heat when they adsorb HC and cool down when they desorb HC.After some purging time,

the canister’s fresh air port side is typically clean. The canister is cleaned out in a direction from the

fresh air port first toward the load port. With hybrids, the fuel tank is typically sealed by a Fuel Tank

Isolation Valve (FTIV). Thus once the Evap canister is purged clean of HC in a hybrid, running loss vapors

do not load the canister. The canister stays clean for duration of drive cycle until a new refueling event.

Method

Since the canister remains clean in a hybrid, there is a unique opportunity to utilize the thermocouple(s)

inside the canister for the purpose of validating the ambient air for polluting HC. If during “purging”, the

thermocouple (TC1) at the fresh air port suddenly registers a heat gain, then this may indicate the

incoming air is polluted with HC and canister fresh air port is being loaded with HC….th...