Emission Control Systems: Description and Operation

Engine Emission Control

Exhaust Gas Recirculation (EGR)

EGR and Crankcase Ventilation Component Location





The EGR (exhaust gas recirculation) system is controlled by a PWM signal from the ECM (engine control module). The system comprises an EGR (exhaust gas recirculation) valve and a gas transfer pipe.





The EGR (exhaust gas recirculation) valve is a 4 pole 60 point stepper motor with an integral cooler unit which is mounted on the side of the induction elbow. The EGR (exhaust gas recirculation) valve receive four 12 Volt signals from the ECM (engine control module). The EGR (exhaust gas recirculation) valve is cooled by the return coolant flow from the electric throttle.

The EGR (exhaust gas recirculation) valve is connected to the LH exhaust manifold via the gas transfer pipe.

Crankcase Ventilation

The V8 engine is ventilated through a part load and a full load breather.

The part load breather is a flexible composite hose connected between the PCV (positive crankcase ventilation) valve mounted above the oil separator in the bank A camshaft cover and the induction elbow. The PCV (positive crankcase ventilation) valve prevents reverse flow into the crankcase.





The full load breather is a flexible hose connected between the oil separator in the bank B camshaft cover and the air intake duct.

The ends of the breather hoses incorporate quick release connectors.





The oil separators consist of wire gauze packed into an open ended enclosure below the breather outlet.