| 摘要 |
PROBLEM TO BE SOLVED: To provide a leakage diagnostic system capable of diagnosing the existence of a leakage hole in a purge device in a shorter time than a conventional time. SOLUTION: In this purge device 10 for purging fuel gas generated by evaporating fuel in a fuel tank 20 to an intake passage of an internal combustion engine, the leakage diagnostic system 100 diagnoses the existence of the leakage hole in the purge device 10 on the basis of pressure in the purge device 10 after a predetermined time by reducing the pressure in the purge device 10 for diagnosing whether or not the leakage hole of a predetermined diameter or more is generated, and includes a negative pressure pump 130 constituted so that capacity can be varied, a secondary driving control means for driving the negative pressure pump by predetermined capacity where the pressure in the purge device 10 becomes reference pressure when the leakage hole of the predetermined diameter is generated in the purge device 10, and a primary driving control means for driving the negative pressure pump 130 by capacity higher than the capacity in its secondary driving control means before its secondary driving control means. COPYRIGHT: (C)2007,JPO&INPIT
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