| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel device for detecting occurrence of abnormality of a heat shielding film formed on the top face of a piston.SOLUTION: When all of the following conditions 1-3 are established, it is determined that a heat shielding film is peeled off. Condition 1: difference in waveform of in-cylinder pressure does not occur in comparison in a combustion cycle. Condition 2: difference in intensity of combustion exciting force in a combustion chamber diameter primary resonance frequency band occurs. Condition 3: intensity of combustion exciting force in a frequency band excluding the combustion chamber diameter primary resonance frequency band does not change.SELECTED DRAWING: Figure 10 |
