CRANKCASE VENTILATION SYSTEM POSITIVE CRANKCASE VENTILATION (PCV)
CRANKCASE VENTILATION SYSTEM A way for gases to escape in a controlled manner fromcrankcase of an internal combustion engine. Internal combustion inevitably involves a small but continualamount of blow-by. Occurs when some of the gases from the combustion leak pastthe piston rings to end up inside the crankcase.
POSITIVE CRANKCASE VENTILATION ( PCV) During World War II, different type of crankcase ventilation be inventedto allow tank engines operate. Normal draft tube ventilator allow water to enter the crankcase anddestroy the engine. PCV reduces blow-by emissions from the engine. 20% of HC emissions produced by a vehicle. The higher the mileage on engine and the greater the wear on the pistonand cylinders, the greater the blow-by into the crankcase.
MAJOR COMPONENT The major component in PCV are PCV valve, a simple spring-loaded valve with a sliding pintle inside. The pintle is tapered like a bullet so it will increase or decreaseairflow depending on its position. The movement of the pintle changes the orifice opening. The PCV valve is located in a valve cover or the intake valley,and fits into a rubber grommet.
HOW PCV WORKS A hose connects the top of PCV valve to a vacuum port onthrottle body, carburetor or intake manifold. This allows the vapors to be siphoned directly into engine w/ogumming up throttle body or carburetor. PCV has the same effect on the air/fuel mixture as a vacuumleak.