Air Temperature Sensor ( Ambient / Intake ): Description and Operation

INTAKE AIR TEMPERATURE SENSOR:



The intake air temperature sensor (arrow) is installed in the mass air flow sensor housing and is therefore situated in the intake air flow of the engine. It is supplied with voltage from the DME control unit via terminal 43 and its ground is connected to the HFM 5. The intake air temperature sensor functions according to the NTC principle.

The signal from the intake air temperature sensor is used by the DME control device to calculate the replacement load signal if the mass air flow sensor fails. It corrects the load which is calculated by the control unit and dependent on the throttle potentiometer. With higher air temperatures, the replacement load signal is downwardly corrected.

The falling air density is also compensated. In addition, the risk of knocking during combustion increases as the intake air temperature rises. Therefore, the ignition angle is corrected towards "late" with high engine temperatures (>90°C) and high intake air temperatures (>30°C).