The task of the camshaft sensor is to work with the crankshaft sensor to define the exact position of the crankshaft drive. Through the combination of both sensor signals, the engine control unit knows when the first cylinder is in the top dead point.
This information is needed for three purposes:
- For the start of injection during sequential injection.
- For the actuation signal of the solenoid valve for the pump-nozzle injection system.
- For cylinder-selective knocking control.
The camshaft sensor works according to the Hall principle. It scans a ring gear on the camshaft. The rotation of the ring gear changes the Hall voltage of the Hall IC in the sensor head. This change in voltage is transmitted to the control unit and evaluated there in order to establish the required data.