Basic Function Of Pressure Sensor Upstream Of Exhaust Gas Turbocharger - GF09.40-P-2001A
Engine 139.9
Sample illustration, pressure sensor upstream of exhaust gas turbocharger
Overview
This document contains information on:
- General
- Function
General
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
Function
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. Based on the signal voltage, the pressure ratio upstream and/or 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.