Method of control system for controlling combustion engines

Abstract

A method and system for optimal control of a combustion engine, where the control could be initiated without the risk of provoking or worsening a knocking condition which could cause engine damages, the control system including an integrating circuit 61-62, which integrates a signal from each combustion event, the signal being dependent on the degree of ionization. The integrated value thus obtained is an indicative measure of the combustion quality and when peak power is needed engine control could strive to optimize the integrated value. The integrated value increases dramatically during knocking conditions which is the reason why a cascade connected reducing circuit 63-64-65 must reduce the integrated value obtained from circuits 61-62. The reduction, which reduction is dependent on the intensity of the knocking condition, is obtained in a final circuit 66. A control could thus be implemented where the knock intensity reduced integrated value could be used as maximizing criteria when controlling a control parameter of the engine, preferably fuel amount, without risking that a harmful knocking condition is provoked or made worse.