| 摘要 |
PROBLEM TO BE SOLVED: To keep high accuracy in calibrating a canister model even when meeting calibration timing in the exposed state of a base air-fuel ratio error immediately after starting. SOLUTION: A controller 11 estimates a fuel quantity desorbed from a canister 24 in purge processing using the canister model, computes the quantity of purge part correction to reduce air-fuel ratio deviation from a stoichiometric air-fuel ratio by performing purge processing at a target purge ratio based on the desorbed fuel quantity, and corrects the quantity of fuel supply to an engine with the quantity of purge part correction. The controller 11 further sets a second limiter narrower in width to the central value of the air-fuel ratio feedback correction quantity than a first limiter, performs purge cut-off when meeting calibration timing in the case of determining the presence of a base air-fuel ratio error by comparing the computed air-fuel ratio feedback correction quantity with the second limiter, and performs first calibration processing to the canister model based on data before and after the purge cut-off. COPYRIGHT: (C)2004,JPO
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