Misfire Pattern Recognition in High Performance SI 12-Cylinder Engine 980521
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 race-track, 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 cut-off or 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.