| 摘要 |
PROBLEM TO BE SOLVED: To enable correct learning by eliminating the influence of an evaporative fuel purge. SOLUTION: In case that a purge valve is switched ON/OFF so as to check the movement of an air-fuel ratio feedback correction valueα, and if an influence exerted on an air-fuel ratio due to an evaporative fuel purge is judged to exist, learning is not allowed. In case that the influence exerted on the air- fuel ratio due to the evaporative fuel purge is judged not to exist, the learning is allowed. The learning of the air-fuel ratio is executed after the influence exerted on the air-fuel ratio due to the evaporative fuel purge is confirmed not to exist, and the updated air-fuel ratio is stored as a temporary air-fuel ratio learning valueαmL. Further, in case that, after the previous purge influence is confirmed whether or not it exists, the purge influence is reconfirmed whether or not it exists after lapse of a predetermined time T, and the influence exerted on the air-fuel ratio due to the evaporative fuel purge results not to exist by this confirmation, the stored temporary air-fuel ratio learning valueαmL is stored as a formal air-fuel ratio learning valueαm. Hereby, the learning of a correct air-fuel ratio without having the influence of the purge can be carried out.
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