Crankcase Ventilation System Description: Notes

Fig 1: View Of Crankcase & Components

Courtesy of GENERAL MOTORS CORP.

The compressed combustion gas which escapes past the piston rings into the crankcase is known as blow-by gas. Blow-by gas contains large amounts of CO and HC. The positive crankcase ventilation (PCV) system prevents the blow-by gas from being emitted into the atmosphere. The PCV system routes the crankcase blow-by gas back into the intake system where the blow-by gas becomes part of the combustion process. The PCV system consists of the following components:

• The PCV valve
• The crankcase vent (breather) or air inlet tube
• The air inlet filter or separator, if used
• Any hoses or couplers