Knock suppression control apparatus for internal combustion engine

Abstract

A knock suppression control apparatus for an internal combustion engine which can avoid erroneous knock detection and hence the erroneous knock suppression control, to thereby ensure knock suppression control with high reliability. The knock suppression control apparatus includes an ion current detecting means (,) for detecting an ion current (i) flowing by way of a spark plug (,) upon combustion of an air-fuel mixture charged in the cylinder, a filter means (,A) for extracting a knock signal (Kj) from an output signal (Ei) of the ion current detecting means (,), a knock decision means (,) for deciding occurrence of a knock event in the engine on the basis of the knock signal (Kj), a control quantity correcting means (,) for correcting a control quantity for the internal combustion engine so as to suppress the knock event on the basis of result (H) of decision made by the knock decision means (,), an integrating means (,A) for arithmetically determining an integral value (Km; Em) which corresponds to an output level of the ion current (Ei), a comparison level setting means (,A) for setting a predetermined comparison reference level (MR) for the integral value (Km; Em), and a correcting quantity arithmetic means (,A) for outputting a correcting signal (M,; M,) for correcting parameters relevant to the knock decision means (,) or alternatively relevant to the control quantity correcting means (,) on the basis of result of the comparison between the integral value (Km; Em) and the comparison reference level (MR).