Patent ID: 7197916

Claim:
A misfire detector detecting an abnormality of a fuel combustion in a cylinder of an internal combustion engine, the misfire detector comprising: a crank angle detecting means continuously and linearly detecting a signal indicative of an angular speed of a crankshaft to produce an output which varies linearly with respect to variation of crankshaft angular speed; a first means for defining a first crank angle range corresponding to at least one part of a power stroke in the cylinder; a second means for defining a second crank angle range corresponding to one part of the power stroke in the cylinder, the second crank angle range being in retard of the first crank angle range; and a misfire determining means for determining whether an abnormal combustion has occurred in the cylinder based on a parameter of the cylinder, the parameter being a difference between a maximum value of an angular speed within the first crank angle range of the cylinder and a minimum value of the angular speed within the second crank angle range of the cylinder.