Circuit/System Description

An intake airflow valve actuator is used to achieve high exhaust gas recirculation rates. It increases the pressure difference between exhaust and intake so that the appropriate exhaust quantity can be mixed with the intake air. The ECM transmits the desired angle as a PWM signal to the airflow valve actuator. The airflow valve actuator operates a DC motor to control the valve based on the PWM signal from the ECM. The airflow valve position is monitored by an internal position sensor.

In the event that the engine control module (ECM) detects the engine speed increases beyond desired control limits. Upon detection, the engine will be shutdown by closing the intake air flow valve and disabling the fuel injectors.