Misfire pattern recognition in high-performance SI 12-cylinder engine

摘要

This paper presents an original procedure for misfire detection in a high-performance, 12-cylinder engine, based on the analysis of the time periods between subsequent combustions. A detailed analysis of the misfire effects on the engine crank-shaft instantaneous speed is presented, then a misfire detection procedure is designed, based on the misfire pattern recognition. The capability of this methodology was then validated under the worst case condition of a random misfire in several tests performed with the vehicle running on a circular racetrack, at low and high load, in different gear, under acceleration and during a normal urban cycle. The results obtained are very interesting because the misfire pattern recognition works well even during cutoff and gear shifts, avoiding false alarm due to the strong influence that these phenomena have on crank-shaft dynamics. In conclusion, same considerations have been done about the procedure capability of detecting more than one misfire within the same cycle.