Patent ID: 7360407
Filing Date: 2008-04-22
Classification: F02P,G01D,G01M

Abstract:
1. A crank angle detecting apparatus comprising: a rotor which rotates in conjunction with a crank shaft of an internal combustion engine, the rotor having an outer periphery and a circumferential direction; a plurality of detection sections provided on the outer periphery of the rotor at equiangular intervals in the circumferential direction of the rotor, each said detection section having a front end and a rear end in the circumferential direction of the rotor, one of the plurality of detection sections being used in detection of a reference crank angle and being longer than other said detection sections in the circumferential direction of the rotor; a pickup disposed in the vicinity of the outer periphery of the rotor for generating a pulse signal every time the pickup detects the front end of each said detection section and for generating another pulse signal every time the pickup detects the rear end of each said detection section; a time detection circuit for sequentially detecting, in response to the pulse signals from the pickup, a detection section time, which is a time interval from detection of the front end of one said detection section to detection of the rear end of the same detection section, and a detection section distance time, which is another time interval from detection of the rear end of one said detection section to detection of the front end of a next said detection section; and a reference angle determination circuit for generating a reference angle detection signal which indicates detection of said one of the detection sections, when at least two ratio conditions decided based on the detection section time and the detection section distance time which are detected by the time detection circuit are satisfied.