P09.41-3086-79
Example illustration |
1 | Charge air pressure and temperature sensor |
Overview
This document contains information on:
General
Function
General
Via the charge air pressure-and-temperature sensor, the combustion engine control unit determines the absolute pressure and the charge air temperature in the intake manifold.
The charge air pressure-and-temperature sensor is located in the intake manifold behind the throttle valve actuator.
Function
Pressure sensor for determining the boost pressure (absolute pressure)
The intake air in the intake manifold is routed via a bore to a silicon diaphragm with four pressure-dependent resistors and deforms this.
The resistors at the silicon diaphragm are located so that the transverse stress of the resistive bridge changes during the deformation of the diaphragm.
The electronic analysis system amplifies this transverse stress and compensates in this way for possible temperature fluctuations or compensates for any manufacturing tolerances of the resistors. It then forwards the measurement voltage filtered in this way to the combustion engine control unit that based on this derives the absolute pressure in the intake manifold.
Temperature sensor for charge air temperature measurement
The electrical resistance of the NTC precision resistor varies according to charge air temperature. Electrical resistance decreases as temperature increases.
The resistance variation results in a voltage change that is used by the combustion engine control unit to calculate the charge air temperature.
NTC (Negative Temperature Coefficient): The electrical resistance falls as the temperature increases (NTC thermistor).