Irregular combustion determining device for an internal combustion engine

摘要

An irregular combustion determining device comprising a variation detecting unit, a first determining unit, and a second determining unit. The variation detecting unit detects a variation in an engine speed on the basis of two successive engine speed detected at predetermined crank angles. The first determining unit determines that an irregular combustion has occurred when the variation in the engine speed detected by the variation detecting unit is larger than a predetermined first variation in the engine speed. When the first determining unit determines that an irregular combustion has occurred, at the next detection of the variation in the engine speed by the variation detecting unit, the second determining unit determines that an irregular combustion has occurred when the variation in the engine speed detected by the variation detecting unit is larger than the predetermined second variation in the engine speed which is smaller than the predetermined first variation in the engine speed.