| 摘要 |
Fuel vapor in a fuel tank (1) is purged into an intake passage (8) of an engine (10) through a purge vent (2, 4, 6). The controller (21) determines whether a leak is present in a purge vent from the fuel tank (1) to a purge control valve (11). The determination process comprises a pull-down process in which a pressure in the purge vent is reduced using a negative pressure in the intake passage (8) and a leak-down process of sealing the purge vent at the reduced pressure and monitoring the pressure variation. The controller (21) calculates an error equivalence amount (DVPII), a pressure component corresponding to sloshing in the fuel tank (1) during the leak-down process, and determines the presence of a leak in a highly accurate manner based a corrected pressure (DVP5A) in which the monitored pressure variation is corrected using the error equivalence amount (DVPII) (S22).
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