Positive Crankcase Ventilation: Description and Operation

Positive Crankcase Ventilation (PCV) System:

SYSTEM OPERATION

The purpose of the PCV system is to reduce hydrocarbon (HC) and carbon monoxide (CO) emissions created by engine blow-by. This system is a closed crankcase ventilation system that consists of a PCV valve, a hose extending from the PCV valve to the intake plenum, a crankcase inlet air filter, and a hose connected from the crankcase inlet air filter to the valve cover.

Crankcase vapors and piston blow-by are removed from the engine by manifold vacuum. These gases are drawn through the [1][2]PCV hose and into the intake plenum, they mix with the calibrated air/fuel mixture, and get burned and expelled with the exhaust gases. No fresh air enters the crankcase with this system.