Method for determining combustion state of internal combustion engine

Abstract

The invention relates of a method for determining a combustion state of an internal combustion engine, for detecting an ion current generated within a combustion chamber of the internal combustion engine, including the steps of measuring a characteristic value of the ion current detected during a period that the ion current is generated and a generation period in which the ion current is generated, and determining a combustion state on the basis of a relation between the characteristic value and the generation period with respect to an elapsed time from an ignition, and the method comprises determining that the combustion state is normal, by setting a determination reference to be larger with respect to the characteristic value and shorter with respect to the generation period, in the case that the elapsed time from the ignition is short, and determining that the combustion is normal, by setting the determination reference to be smaller with respect to the characteristic value and longer with respect to the generation period in correspondence that the elapsed time from the ignition becomes longer.

Dependencies are inferred from the claim text.