Patent ID: 6411886
Filing Date: 2002-06-25
Classification: F02P,G01L,Y02T

Abstract:
A method of detecting and controlling detonation of an internal combustion engine (2), comprising the steps of:a) acquiring (10) a vibration signal (D) proportional to the intensity of vibration on the crankcase; b) wide-band filtering (11) said vibration signal (D) to generate a first intermediate signal; c) rectifying (12) said first intermediate signal to generate a second intermediate signal; d) integrating (13) said second intermediate signal to generate a first numeric value; e) calculating (14) a logarithm of said first numeric value to obtain a second numeric value (xi); f) calculating (15) a mean value (&mgr;i) as a function of said second numeric value (xi); characterized by comprising the steps of:g) calculating (16) a difference between said second numeric value (xi) and said mean value (&mgr;i) to obtain a third numeric value (&dgr;i); h) comparing (17) said third numeric value (&dgr;i) with a predetermined threshold value (&dgr;o); m) determining (18) the presence of detonation in the event said third numeric value (&dgr;i) has a first predetermined relationship with said predetermined threshold value (&dgr;o); n) forming a detonation index indicating the behaviour of the engine in terms of detonation; and o) calculating, from said detonation index, a correction value to be added to the spark lead.