What is the working principle of a camshaft position sensor?

[JeremiahDella]

The working principle of a camshaft position sensor is to detect the valve timing of an engine by monitoring the rotational angle of the camshaft. The sensor's probe contains a detection coil that can sense nearby metal objects. When no metal is present, the LC circuit (including the probe) remains in a resonant state. When a metal object approaches the probe, the detection coil induces eddy currents on the metal surface, causing the LC parallel circuit to detune and the output voltage to decrease. The camshaft position sensor, also known as the crankshaft position sensor, serves as a crucial reference for determining the engine's ignition timing. Based on structure and waveform, these sensors can be categorized into magnetic induction type (producing sinusoidal wave output) and Hall-effect type (producing square wave output).