| 摘要 |
An internal combustion engine system includes: an in-cylinder pressure sensor 30; a crank angle sensor 42; and a seal portion 34 that seals a space between an outer face of a housing 301 and a wall surface of a cylinder head 32. A slope k that is a ratio of the amount of decrease in a heat release amount Q relative to the amount of increase in a crank angle is calculated in a period during an expansion stroke from a combustion end point ¸ max until an opening timing of an exhaust valve 22. The existence or nonexistence of an abnormality in the sealing function of the seal portion 34 is determined based on whether or not a ratio X of the amount of decrease in the slope k to the amount of increase in an engine speed is greater than a threshold value ±. |
