Evaporative Emissions System: Description and Operation

Crankcase And Evaporative Emission Control System (PCV & EVAP):

SYSTEM OPERATION

The evaporative emission control system uses a charcoal cannister to store the vapors generated by the fuel in the fuel tank. The fuel vapor is stored in the cannister until it is drawn into the combustion chamber and burned when the engine is running.

To control crankcase emissions when the engine is running at idle the purge control valve is opened slightly and a small amount of blow-by gas is drawn into the combustion chamber and burned. At high engine speed or heavy-load condition the purge control valve is further opened and a larger amount of blow-by gas is drawn into the combustion chamber.