Increment wheel
The incremental wheel is a ferromagnetic gear installed in motor vehicles .
Increment wheels are, for example, the flywheel or the pole wheel for the ABS sensors. On the basis of periodic gaps in the ring gear or in the wheel, an induction transmitter can generate a speed signal based on the changes in the magnetic field . A uniform tooth structure corresponds to a sinusoidal stress curve. Furthermore, a specific gear wheel position can be transmitted to a control unit by using gaps of different sizes at specific intervals, which results in a change in the voltage curve.
In vehicles with an on-board diagnosis system, there is a gear on the crankshaft that can be used to detect malfunctions in the combustion engine . By dividing this incremental wheel into three sectors of 120 degrees for the 6-cylinder engine and two sectors of 180 degrees for the 4-cylinder engine, combustion misfires can be detected because the acceleration through the combustion is missing. The control unit uses the camshaft sensor to identify the cylinder where the misfiring occurs. If the misfire rate is so high that it could endanger the catalytic converter , the control unit activates the flashing engine control lamp and the fuel supply to the relevant cylinder is switched off.
In addition, the increment wheel is required to set the TDC point. The control unit needs this signal as a reference mark for ignition and injection.
See also
literature
- Karl-Heinz Dietsche, Thomas Jäger, Robert Bosch GmbH: Automotive pocket book. 25th edition, Friedr. Vieweg & Sohn Verlag, Wiesbaden, 2003, ISBN 3-528-23876-3