Positive Crankcase Ventilation: Description and Operation

Positive Crankcase Ventilation System:

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 throttle body, a crankcase inlet air filter, and a hose connected to the air cleaner assembly.

The PCV system operates on manifold vacuum: Fresh air is drawn in through the air cleaner and crankcase inlet filter, into the engine, and the vapors that come out through the PCV valve are blow-by gases. These gases are drawn through the PCV hose and into the throttle body, they mix with the calibrated air/fuel mixture, and get burned and expelled in the combustion process.