Engine control unit having cylinder determination function

摘要

A crank signal generated by a crank angle sensor has a front pulse missing portion and a back pulse missing portion in a pulse train of every predetermined angle interval. The level of a cam signal generated by a cam angle sensor becomes different in the pulse missing portion of the crank signal. A level different from that in the pulse missing portion continues for a period of predetermined angles before the pulse missing portion. A microcomputer determines each of the front and back pulse missing portions in the crank signal on the basis of the level of the cam signal in the pulse missing portion of the crank signal in two cycles of the rotation of a crankshaft of the engine and the duration of a different level before the pulse missing portion.