| 摘要 |
PROBLEM TO BE SOLVED: To improve prediction accuracy of an occurrence of an engine stall in a combustion state diagnostic device which diagnoses a combustion state of an internal combustion engine.SOLUTION: A combustion state diagnostic device acquires a first threshold and a second threshold which are set with respect to peak values of heat generation rate waveforms in cycles and an actual heat generation rate in each cycle. The combustion state diagnostic device determines that an occurrence of an engine stall is expected when an identical cylinder in a steady state has: the peak value of the actual heat generation rate waveform in a previous (a n-1th) cycle exceeding the first threshold and the peak value of the actual heat generation rate waveform in a current (a nth) cycle falling below the second threshold; or the peak value of the actual heat generation rate waveform in the previous cycle falling below the second threshold and the peak value of the actual heat generation rate waveform in the current cycle exceeding the first threshold. |
