JPS57113344A - Ignition limit detector for internal combustion engine - Google Patents

Abstract

PURPOSE:To detect partial combustion state immediate before misfire at a constant level regardless of running conditions by determining the ratio between integrated values of pressures in a cylinder up to the top dead center (TDC) from a certain angle position and up to a certain angle position from the top dead center. CONSTITUTION:A pressure detector 1 detects pressures in the cylinder of an internal combustion engine. A crank angle detector 2 emits signals for each crank angle of the internal combustion engine together with a signal for the first angle positionI(-thetaA) of the internal combustion engine during the compression stroke and the second angle position II (+thetaA) at a symmetrical position between the angle positionIand the TDC. An arithmetic unit 3 connects the pressure detector 1 and the crank angle detector 2 and determines a value S1' as the integration of the pressures P in the cylinder by the signal for the crank angle from the angle positionI(-thetaA) to TDC and a value S2' as that from TDC to the angle position II (+thetaA) for each combustion from signals of the pressure detector, and a judges whether the ratio S2'/S1' between the values is above or below the predetermined value alpha. This always enables the detection of the ignition limit of the internal combustion engine.