Positive Crankcase Ventilation: Description and Operation

PURPOSE
The PCV valve is used to to reduce HC emissions by directing crankcase blow-by back into the intake manifold for combustion.

PCV Operation:

OPERATION
The PCV valve contains a spring loaded valve that allows the amount of blow-by reintroduced into the intake manifold to be controlled. The valve passage size is dependent upon intake manifold vacuum and crankcase pressure.