Air Flow Meter/Sensor: Description and Operation

GF07.07-P-6000BK Component Description For The Hot Film MAF Sensor







Location
The hot film MAF sensor is located at the rear at the variable intake manifold.

Task
Detects the air mass led to the engine and the intake air temperature.







The air which is supplied to the engine flows through the air mass meter in the air intake duct and thus influences the temperature at the hot film sensor.

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 heating resistor [R(H)] is detected by the sensor resistor [R(S)]. If a temperature change occurs as a result of an increased or reduced air flow, the electronics adapts the voltage at the heating resistor [R(H)] until the temperature difference is again achieved.

This control voltage is used by the engine control unit as a measure for the metered air mass. The intake air temperature is detected by an additional NTC resistor.