Evaporative Emissions System: Description and Operation

Evaporative Emissions Control System Schematic:

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 consumed in the normal combustion process.

Fuel Vapor Canister:

VAPOR CANISTER AND PURGE OPERATION

The venting of vapors to the canister is controlled by a diaphragm operated control valve. When the engine is running, manifold vacuum is supplied at the top of the purge valve allowing the control valve diaphragm to open. The lower port on the purge valve is connected to ported vacuum.