| 摘要 |
PROBLEM TO BE SOLVED: To correctly detect the quantity change of combustion ion, generated at the combustion chamber of an internal combustion engine, in a combustion state detecting device. SOLUTION: A combustion state detecting device consists of a pair of opposed electrodes 11, 12 provided at the combustion chamber of an internal combustion engine, an AC voltage applying means 2 for applying AC voltage between the opposed electrodes 11, 12, a current detecting means 3 for detecting a current flowing in the opposed electrodes 11, 12 so as to output a current signal corresponding to the current, a voltage trigger generating circuit 25 for generating trigger in a fixed phase to the AC voltage, and a sample and hold circuit 41 for holding the current signal when trigger is generated. The increase/decrease of combustion ion existing between the opposed electrodes 11, 12 is detected without being influenced by charging and discharging currents due to capacity between the opposed electrodes 11, 12. |
