Evaporative Emissions System: Description and Operation

Fuel Vapor Canister:

SYSTEM DESCRIPTION

The Evaporative Emission Control System (EECS) used on this vehicle is the charcoal canister storage method. This method transfers fuel vapor from the fuel tank to an activated carbon storage canister. This retains the fuel vapors when the vehicle is not operating. When the engine is running, the fuel vapor is purged from the carbon element by intake air flow, and is consumed in the normal combustion process.


VAPOR CANISTER

Purging of the vapor canister is controlled by a purge valve. The throttle valve position controls the canister purge rate. Manifold vacuum causes the purge valve to open, which allows for fuel vapor to flow through the purge line once the engine is running above the base idle speed.