Engine Emission Control

ENGINE EMISSION CONTROL

Positive Crankcase Ventilation (PCV) System
The PCV system consists of a valve and several hoses. The PCV system recycles crankcase gases through the engine where they mix with the incoming air/fuel charge.

The PCV valve regulates the amount of ventilation air and crankcase gas supplied to the intake manifold and also prevents backfiring into the crankcase. The PCV system helps to reduce hydrocarbon emissions from the engine.

Exhaust Gas Recirculation (EGR) System
The EGR system consists of a valve, vacuum regulator, tube and a differential pressure feedback EGR sensor.

The EGR system recycles measured quantities of exhaust gas back through the engine where they mix with the incoming air/fuel charge.

The powertrain control module controls the vacuum regulator valve with grounding pulses. This regulates the quantity and duration of the vacuum signal supplied to the EGR valve therefore the valve lift and opening time are controlled.

The differential pressure feedback EGR sensor provides the powertrain control module with data relating to the exact quantity of exhaust gas being recirculated by measuring the differential pressure across a calibrated orifice in the supply hose. Therefore, closed loop control is achieved.