| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform accurate leak diagnosis for an evaporating purge system while securing the frequency thereof. Ž<P>SOLUTION: The evaporating purge system has a fuel tank 1, a purge passage 10 for purging fuel evaporating gas from the fuel tank 1 to an intake passage 5 of an internal combustion engine, and an on-off valve 5 mounted in the purge passage 10. The leak diagnosis device for the evaporating purge system closes the on-off valve 5 to block the evaporating purge system including the fuel tank 1, and performs leak diagnosis to determine whether there is leakage from a purge valve 5 or not in accordance with a pressure change in the evaporating purge system in this state. It comprises a diagnosis duration time varying means 13 for controlling a diagnosis duration time from blocking the evaporating purge system to determining whether there is leakage from the purge valve 5 or not, to be varied depending on current operation. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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