Boost pressure positioner, component description - GF09.40-P-4020P

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ENGINE 642.9 in MODEL 203.0 /2, 204.0 /2, 209.3 /4, 221.0 /1

ENGINE 642.9 up to 31.5.06 in MODEL 211.0 /2 /6, 219.3 up to 31.5.06

ENGINE 642.9 in MODEL 164.1 /8, 251.0 /1 except CODE (494) USA version

ENGINE 642.9 in MODEL 461.3, 463.3

Fig 1: Identifying Boost Pressure Positioner

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Location

The boost pressure positioner is located at the turbocharger.

Task

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

Engine speed
Quantity injected
Coolant temperature
Intake temperature
Atmospheric pressure

Design

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

Function

An adjustment shaft is turned by a worm drive, which is connected to the guide vanes in the turbocharger.