| 摘要 |
PROBLEM TO BE SOLVED: To provide a purge flow diagnostic system for improving diagnostic accuracy, while minimizing the deterioration in fuel economy. SOLUTION: This purge flow diagnostic system diagnoses abnormality of an evaporated fuel processing system for introducing evaporated fuel to a combustion chamber, by opening and closing a purge control valve from a purge passage for connecting a fuel tank to an intake passage, by adsorbing the evaporated fuel by a canister, and has a drain cut valve for opening one end of the purge passage in the atmosphere, a pressure sensor for detecting pressure of the purge passage, a first diagnostic means performed while normally operating an internal combustion engine, a second diagnostic means performed when determined as abnormal by the first diagnostic means, fixing the purge control valve to predetermined opening and comparing pressures before and after opening and closing the drain cut valve, and an internal combustion engine stopping prohibiting means S401 prohibiting stopping of the internal combustion engine when performing the second diagnostic means. COPYRIGHT: (C)2007,JPO&INPIT
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