Detecting a marker in an engine position sensing system

摘要

An engine position sensing system is of the type in which a toothed wheel having circumferentially spaced marks is mounted on the engine crankshaft with a sensor located adjacent the toothed wheel to detect passing marks. The engine rotational position is indicated by a marker on the toothed wheel defined by a missing tooth. The marker is detected by taking the previous, current and subsequent intervals A, B and C respectively between marks and performing an operation thereon in which the current interval B and the previous and subsequent intervals A and C are processed and compared with a constant K according to the formula B2/(AxC)>K. Upon detection of the marker an appropriate signal can be generated and sent to an engine management system. K is preferably between 2.6 and 3.5 and typically 3.