Turbocharger System Description
|
|
Turbocharger System Description
|
The turbocharger increases engine power by pumping compressed air into the combustion chambers, allowing a greater quantity of fuel to combust at the optimal air/fuel ratio.
|
Turbocharger Pressure Sensor
|
The turbocharger pressure sensor is mounted on the intake manifold and measures boost pressure and air temperature.
|
Turbocharger Vane Position Control Solenoid or Boost Pressure Actuator
|
The turbocharger for this system uses a turbocharger vane position control solenoid valve or a boost pressure actuator and is controlled by the engine control module (ECM). The turbocharger vane position control solenoid valve uses an ignition voltage circuit and a control circuit. The turbocharger vanes are controlled to vary the amount of boost pressure. The boost pressure can be controlled independent of engine speed. There are 11 controllable vanes in this turbocharger. The vanes mount to a drive ring that can be rotated to change the vane angle. The ECM will vary the boost dependent upon the load requirements of the engine.
The turbocharger vanes are normally open when the engine is not under a load. The ECM will close the turbocharger vanes to increase engine power and to create a high pressure, using boost pressure actuator.
The ECM will often close the turbocharger vanes 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 turbocharger vanes at low load conditions in order to accelerate engine coolant heating. The ECM may also close the turbocharger vanes under exhaust braking conditions.
The charge air cooler is located in front of the radiator. The turbocharger supplies hot compressed air from the turbine by sucking exhaust gas to the engine to increase power. The airflow through the radiator cools the hot compressed air from the turbocharger.
|
Engine Control Module (ECM)
|
The engine control module (ECM) controls all turbocharger control functions. The ECM monitors information from various sensor inputs that include the following:
|
•
|
The accelerator pedal position (APP) sensor
|
|
•
|
The engine coolant temperature (ECT) sensor
|
|
•
|
The mass air flow (MAF) sensor
|
|
•
|
The intake air temperature (IAT) sensor
|
|
•
|
The vehicle speed sensor (VSS)
|
|
•
|
The transmission gear position or range information sensors
|
|
•
|
The manifold absolute pressure (MAP) sensor
|
