Abnormality diagnosis device of a crank angle detection system

摘要

A crank angle sensor (14) has a first sensor (15) and a second sensor (16) along an outer circumferential part of a signal rotor (12) are arranged, and determines a direction of rotation of a crankshaft (11) based on a relationship between the outputs of the two sensors (15, 16). The firing point (14) transmits a crankshaft with a pulse width which is different according to the direction of rotation, to a machine control circuit (18) from. The machines control circuit (18) measures a period of time which is necessary, so that the crank angle sensor (14) a predetermined number of the crank angle signals, than a predetermined crank angle time. The machines control circuit (18) is determined by a presence / absence of an abnormality in the crank angle sensor (14) based on whether the instantaneous predetermined crank angle time of the preceding predetermined crank angle time (or a predetermined crank angle period of time, the of the preceding predetermined crank angle period of time) is preceded by a predetermined amount or more fluctuated has.