B2/5 | Hot film mass air flow sensor |
B28/11 | Intake manifold pressure sensor |
N07.07-2007-05
Location
The hot film MAF sensor is located at the front right on the air filter housing.
Task
The CDI control unit (N3/21) detects the air mass drawn in via the hot film MAF sensor.
Schematic representation, structure |
4 | Electronics housing |
5 | Hot film sensor |
RH | Heating resistor |
RL | Temperature resistance |
RS | Sensor resistance |
B2/5 | Hot film mass air flow sensor |
N07.07-2000-06
Function
The electronics in the hot film mass air flow sensor regulates via a changeable voltage the temperature of the heating resistor in such a way, that its temperature lies 160°C above the intake air temperature which was detected by the intake manifold pressure sensor. The temperature of the heating resistor is detected via the sensor resistor. For temperature changes for reasons of increased or reduced rate of air flow the electronics readjusts the voltage at the heating resistor, until the temperature difference is reached again. The control voltage is used by the CDI control unit to measure the air mass flow. The air mass is transmitted via a frequency signal (low frequency for low air mass) to the CDI control unit.