Positive Crankcase Ventilation: Description and Operation

Positive Crankcase Ventilation 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 regulating orifice, a hose extending from the air cleaner to the valve cover, and a valve cover baffle plate.

The PCV system operates on manifold vacuum: Fresh air is drawn in through the air cleaner and into the valve cover, and the vapors that come out through the [1][2]PCV regulating orifice are blow-by gases. These gases are drawn through the regulating orifice and into the intake manifold, they mix with the calibrated air/fuel mixture, and get burned and expelled with the exhaust gases. The regulating orifice is used to control the amount of blow-by gases to be consumed by the engine.