Patent ID: 6275041
Filing Date: 2001-08-14
Classification: F02P

Abstract:
A combustion state detecting apparatus for an internal combustion engine, comprising:a spark plug for generating a spark discharge upon application of a high voltage generated by an ignition coil in response to an ignition signal to thereby fire an air-fuel mixture within a cylinder of the internal combustion engine;ion current detecting means for detecting as ion current detection signals an ion current corresponding to an amount of ions produced within said cylinder immediately after combustion of said air-fuel mixture;signal detecting means designed for comparing said ion current detection signal outputted from said ion current detecting means with a first reference voltage to thereby output a first decision signal while comparing the ion current detection signal with a second reference voltage to thereby output a second decision signal while invalidating output of said second decision signal during a predetermine time period from a time point at which said comparison of the ion current detection signal with said second reference voltage is started; andestimating means for estimating a cause for nongeneration of a combustion signal on the basis of output statuses of said first decision signal and said second decision signal.