Crankcase Ventilation System: Description
Crankcase ventilation systems are designed to prevent contaminating hydrocarbons from escaping to the atmosphere. This is accomplished, in most cars, by routing vapors from the crankcase through a vacuum-controlled ventilating valve (PCV Valve) into the intake manifold. The vent system for the 1.6L does not use a PCV system. The system used in the 1.6L engine evacuates crankcase vapors that are drawn into the intake manifold in metered amounts according to the manifold depression and the fixed orifice as they became available (see Fig 1 ). If the availability is low, air may be drawn in along with the vapors. If the availability is high, some vapors will be delivered to the intake manifold and any amount over that will go into the air cleaner. The fixed orifice is the critical point of the system and determines the amount of blow-by that is routed back to the combustion chamber.