| 摘要 |
PROBLEM TO BE SOLVED: To accelerate purge from a canister while avoiding worsening of operability and miniaturize the canister. SOLUTION: During idling operation, purge is started in the state of setting the lower limit value of a feedback correction factorαas the first tower limit valueαL1 (S2-S6). In a stage of the average value EVALPHA of the correction factor f reaching a specified range corresponding to the lower limit valueαL1 , whether the decrease of the correction factorαis due to purge is judged (S8-S10). Since the change of the average value EVALPHA that can be generated in the case of purge gas being rich to the maximum is fixed by a purge rate, abnormality is judged in the case of the change being larger than that, and the lower limit value is not lowered (S11). In the case of being normal, the lower limit value is switched to the lower second lower limit valueαL2 , and the ON duty ratio of a purge control valve is further increased (S12-S15). Purge therefore makes progress at an early stage.
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