Combustion state-detecting system for internal combustion engines

摘要

A combustion state-detecting system for an internal combustion engine calculates a first average speed by averaging the rotational speed of the engine over a time period corresponding to duration of one stroke of a cylinder, and a second average speed by averaging the rotational speed of the engine over a time period corresponding to duration of one cycle of all strokes of the cylinder. The system calculates a difference between the first average speed and the second average speed, and determines based on the difference whether or not the combustion state of the engine is abnormal.