Description And Operation
The timing sensors are two Hall effect sensors. A current-carrying semiconductor layer immersed in a normal magnetic field generates a potential difference known as a Hall voltage at its terminals.
The timing sensors are used by the Engine Management Node, together with the rpm and TDC signal, to recognise the position of the cylinders and determine the injection and ignition point. They are positioned on the camshaft housing, in the appropriate positions, and they face the pulleys next to the intake and exhaust side camshafts.
The operating features and conditions are:
A current-carrying semiconductor layer immersed in a normal magnetic field (force lines at right angles to current direction) generates a potential difference known as a Hall voltage at the T terminals.
If current intensity remains constant, the generated voltage only depends on magnetic field intensity. Periodic changes in magnetic field intensity are sufficient to generate a modulated electrical signal with frequency proportional to the speed of magnetic field change.
The distance between the sensor and the toothed wheel on the intake camshaft is altered to produce this change and the reference mark for the timing adjustment operation is used in the process.
The rotation of the pulley changes the distance and produces a high voltage signal corresponding to the reference mark.