| 摘要 |
PROBLEM TO BE SOLVED: To accurately diagnose the function of a crankcase ventilation device. SOLUTION: The function diagnosing method for the crankcase ventilation device of an internal combustion engine is proposed with a cycle operation valve 5 disposed in a ventilation pipe 3. The cycle operation valve 5 is controlled as a function of pressure in the crankcase 2, and a pressure sensor 13 measures the pressure. At higher pressure, the cycle operation valve is opened for discharging vapor through an intake pipe 14. Here, the cycle operation valve 5 is controlled as a function of operation request, exhaust gas request, and/or load state. It can be detected based on the pressure change, for example, whether or not an oil level is sufficient, leakage exists in the closed ventilation device, or the internal combustion engine 1 has larger abrasion.
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