Pressure Sensor Upstream Of Exhaust Gas Turbocharger, Basic Function - GF09.40-S-2001A

Engine 200, 274 

Example illustration of engine 200 

Overview 

This document contains information on:

• Location 
• Function 

Location 

The pressure sensor upstream of the right exhaust gas turbocharger is located on the top right on the combustion engine upstream of the exhaust gas turbocharger.

Function 

The pressure sensor upstream of the right exhaust gas turbocharger records the intake air pressure upstream of the exhaust gas turbocharger for the following tasks:

• Monitoring of air filter soiling
• Monitoring of boost pressure control
• Plausibility test of other pressure sensors

The air pressure deforms a diaphragm that acts upon a potentiometer. As a result, the potentiometer changes the resistance value and influences the signal voltage, which provides the combustion engine control unit with information about the intake air pressure upstream of the exhaust gas turbocharger.

If the pressure difference to the atmospheric pressure (pressure sensor in the combustion engine control unit) is too great when the engine load is high, the air filter is clogged. In this case, power output is limited by the boost pressure control, and also by the throttle valve if necessary.

The signal voltage of the pressure sensor downstream of the air filter is used to monitor the boost pressure. On the basis of the signal voltage, the ratio of pressure upstream/downstream of the exhaust gas turbocharger is calculated for the boost pressure control.

The signal voltage of the pressure sensor upstream of the right exhaust gas turbocharger is required for the plausibility test of further pressure sensors.