Exhaust Gas Recirculation: Description and Operation

This system recirculates a small amount of exhaust gas into the intake manifold to reduce the combustion temperature, and reduce the NOx emissions.
This system consists of the EGR control valve, EGR solenoid valve, engine control module (ECM) and input devices





Operation
Cold Engine (coolant temperature less than 131°F [55°C]):
EGR operation is stopped to improve driveability when the engine is cold.

Warm Engine (coolant temperature more than 131°F [55°C]):
The engine control module controls the solenoid valves to supply EGR gases as described below.