Patent ID: 6739181
Filing Date: 2004-05-25
Classification: F02D,F02P,G01L

Abstract:
A combustion detecting apparatus of an engine comprising:ion current detecting means for detecting an ion current flowing in electrodes of a spark plug of an engine and outputting an ion current detecting signal having a voltage in accordance with the ion current; A/D conversion means for subjecting the ion current detecting signal to A/D conversion at every predetermined time period; reference voltage producing means for producing a reference voltage large or small of which is compared with the ion current detecting signal; voltage change storing means for comparing the ion current detecting signal and the reference voltage and storing that the ion current detecting signal traverses the reference voltage; A/D conversion value storing means for storing an A/D conversion value by the A/D conversion means; erasing means for determining whether the ion current detecting signal is stored to traverse the reference voltage in the voltage change storing means, erasing a stored value of the A/D conversion value storing means prior to an A/D conversion timing at current time and erasing a memory of the voltage change storing means when the reference voltage is stored to be traversed at every timing of subjecting the ion current detecting signal to A/D conversion by the A/D conversion means (hereinafter, referred to as A/D conversion timing); and combustion condition determining means for determining a combustion condition of the engine based on a stored value of the A/D conversion value storing means which has not been erased by the erasing means continuously over A/D conversion timings of more than a predetermined number of times.