Turbocharger Vane Control Actuator
The turbocharger uses a vacuum operated vane position actuator with an integral vane position sensor, to control the turbocharger vane angle. The actuator utilizes a remotely mounted solenoid valve to regulate the vacuum. The solenoid is controlled by the engine control module (ECM), which provides ignition voltage and a pulse width modulation (PWM) low side drive control circuit. The turbocharger vane angles are varied to control the amount of boost pressure, dependent upon the load requirements of the engine. The turbocharger vanes are mounted to a drive ring that can be rotated by the actuator to change the vane angle. The ECM uses the turbocharger vane position sensor to monitor the turbocharger vane angle.
The Engine Control Module (ECM) performs the turbocharger learn procedure automatically when the enabling criteria have been met. After each ignition cycle, and before the enable criteria have been met, the ECM will use the previously learned value. If the ECM does not have a previously learned value, it will default to a stored calibrated value.
The turbocharger vanes (2) are normally open when the engine is not under a load. The ECM commands the boost pressure actuator to close the turbocharger vanes (1) to increase engine power by increasing boost pressure.
The ECM may close the vanes (1) to create back pressure to drive exhaust gas through the exhaust gas recirculation (EGR) valve as required. At extreme cold temperatures, the ECM may close the vanes (1) at low load conditions in order to accelerate engine coolant heating. The ECM may also close the vanes (1) under exhaust braking conditions.