The evaporative
emission control system prevents hydrocarbon (HC) vapors from the fuel
tank from escaping into the atmosphere where they could form photochemical
smog. Gasoline vapors are collected in the charcoal canister. The Canister
Close Valve (CCV) closes off the air inlet into the canister for leak
detection of the evaporative emission system. The CCV also prevents fuel
vapors from escaping from the canister. When the engine purges the HC
vapors from the canister, the clean air comes into the canister through
the canister air-filter and the CCV.
