Misfire detection system for internal combustion engine

摘要

A misfire detection system for an engine, includes a crank angle sensor, a misfire detection unit, an acquisition unit and a correction unit. The misfire detection unit detects a misfire condition in the engine based on a misfire index. The misfire index is derived using a rotation speed of the crankshaft as a reference, corresponded to a predetermined order of engine speed, and has a correlation with an amount of variation in an angular velocity of the crankshaft such that a value of the misfire index varies in accordance with the amount of variation in the angular velocity. The acquisition unit obtains a parameter relating to a compression end pressure in a cylinder of the engine. The correction unit corrects the misfire index, or a predetermined misfire detection parameter used together with the misfire index during misfire detection, based on the parameter.