Charging Pressure Control

Charging Pressure Control

Overview of functions
On the M57TU TOP, the charging pressure is controlled with three actuators:
- Turbine control flap
- Compressor bypass plate
- Wastegate valve

The turbine control flap controls the distribution of the exhaust flow between the large and small turbines. The adjustment is pneumatic by means of an pressure converter and a vacuum unit.
The compressor bypass plate opens the bypass around the small compressor at high loads and engine speeds. This enables the high air masses created by the large compressor to flow to the charge air cooler without hindrance. The adjustment is pneumatic by means of an electropneumatic changeover valve and a vacuum unit. The wastegate valve limits the maximum charging pressure by diverting excess exhaust past the large turbine into the exhaust system. The adjustment is pneumatic by means of an pressure converter and a vacuum unit.

Diagnosis instructions
The three actuators can be activated via diagnosis. The engine must be running to create the necessary partial vacuum.