Evaporative Emissions System: Description and Operation

Fuel Vapor Canister:

Evaporative Emission 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.


PURGE VALVE

When the engine is running, manifold vacuum is supplied to the top of the purge valve. Vacuum to the control valve allows the valve to open. The rate of purge is dependent upon throttle position.