Operation

OPERATION

The Exhaust Gas Recirculation (EGR) throttle valve adjusts the flow of fresh air into the engine during EGR operation. A signal from the Engine Control Module (ECM) controls the operation of the EGR throttle valve. The position at which the ECM will set the valve depends on the blended quantity of exhaust gas that needs to be recirculated into the engine in order for the exhaust gas to remain with the target emission level, which the ECM calculates based on input received from the oxygen sensors. When not actuated, the EGR throttle valve is in the open position.