Component description for a hot film MAF sensor - GF07.07-P-6000SM

ENGINE 113.986

ENGINE 113.987

ENGINE 113.988

ENGINE 113.989

Task

The hot film MAF sensor detects the suctioned in air mass and the integral temperature sensor for the intake air temperature.

Fig 1: Locating Hot Film Mass Air Flow Sensor - Engine 113.986/987/988/989

Design

Fig 2: Identifying Hot Film Maf Sensor Components - Engine 113.986/987/988/989

Schematic representation

Fig 3: Hot Film Mass Air Flow Sensor Schematic Representation - Engine 113.986/987/988/989

Function

The electronics in the hot film mass air flow sensor controls the temperature of the heating resistor (R _H ) by means of a variable voltage so that its temperature is 160°C above the intake air temperature detected by the temperature resistor (R _L ). The temperature of the thermistor is measured over the sensor resistance (R _S ).

If a temperature change occurs as a result of increased or reduced air flow, the electronic control corrects the voltage at the heating resistor until the temperature difference (160°C) is reached again. This control voltage is used by the ME control unit (N3/10) as a measure for the metered air mass.

The intake air temperature is detected by the integral NTC resistor and transmitted to the ME control unit as a voltage signal.