Patent ID: 6805096
Filing Date: 2004-10-19
Classification: F02D

Abstract:
A cylinder judgment apparatus of an engine comprising:a plurality of cam sensors each of which outputs cylinder judgment signals at every uneven crank angle interval; and a control unit that is input with cylinder judgment signals from said plurality of cam sensors, and judges a cylinder corresponding to each stroke in combustion cycle based on said cylinder judgment signals, wherein said control unit:counts up the number of cylinder judgment signals output from one cam sensor during a time period between a previous output and a present output of cylinder judgment signals from the other cam sensor, to judge a specific cylinder based on the number of outputs, so that cylinders other than the specific cylinder are judged based on the judgment result and the cylinder judgment signals; and at the same time, each time the cylinder is judged by the above method, calculates a period of from the previous cylinder judgment to the present cylinder judgment, to judge erroneous detection of cylinder judgment signal due to noise based on a ratio between a previous calculation value and a present calculation value of said period, and when said erroneous detection is judged, cancels the cylinder judgment result based on said cylinder judgment signals.