Patent ID: 7305871

Claim:
A cylinder discriminating device comprising: a cylinder discriminating section, wherein: a crank rotor includes a plurality of tooth portions arranged at regular intervals, and first and second non-tooth portions asymmetrically positioned on a periphery of the crank rotor, the first non-tooth portion positioned to correspond to a top dead center of a specific cylinder of an engine; a crank signal is outputted when the cylinder discriminating section detects each of the plurality of the tooth portions; a cam signal is outputted when the cylinder discriminating section detects a predetermined tooth portion on a periphery of a cam rotor; and the cylinder discriminating section discriminates the specific cylinder by detecting the first non-tooth portion based on number of the crank signals detected during a time period from a time when one of the first and second non-tooth portions is detected to a time when the other of the first and second non-tooth portions is detected, and by detecting whether or not the cylinder discriminating section detects the cam signal during the same time period.