Component description for boost pressure actuator - GF09.40-P-4020P

ENGINES 642.8 in MODEL 463.3 as of model year 2011/YoM 10

ENGINES 642.9 in MODEL 203.0, 204.2, 221.0/1, 203.2, 204.0 up to model year 2008/YoM 07

ENGINES 642.9 up to 31.5.06 in MODEL 219.3, 211.6/0/2 up to 31.5.06

ENGINES 642.9 in MODEL 251.0, 164.8, 251.1, 164.1 except CODE (494) USA version up to model year 2008/YoM 07

ENGINES 642.9 in MODEL 209.3/4

ENGINES 642.9 in MODEL 463.3, 461.3

ENGINES 642.8 in MODEL 461.3

Fig 1: Identifying Charge Pressure Positioner

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Location

The boost pressure actuator is located on the turbocharger.

Task

The boost pressure positioner is actuated by the CDI control unit (N3/9) and changes the position of guide vanes in the turbocharger and thus the boost pressure. Boost pressure control of the turbocharger improves the torque characteristics in full-load operation and gas cycle under partial-load conditions. The specified value for the boost pressure depends on the following influencing factors:

RPM
Quantity injected
Coolant temperature
Intake air temperature
Atmospheric pressure

Design

The boost pressure positioner consists of an actuator motor and an electronic unit.

Function

An adjusting shaft is turned via a worm drive which is connected with the guide vanes in the turbocharger.