| 摘要 |
PROBLEM TO BE SOLVED: To provide an air-fuel ratio fluctuation suppressing device for an internal combustion engine, for suppressing the fluctuation of an air-fuel ratio due to thick fuel from a breather passage at other than the time of oiling without causing the complication of the passage, and the increase of the engine weight. SOLUTION: When the opening of a differential pressure regulating valve in a breather passage is judged ('YES' in S120), and influence is exserted on air-fuel control ('YES' in S130), the opening of a purge control valve is adjusted (S160) to limit the purge of fuel to an engine suction passage, thereby preventing direct purging oil into an engine suction passage intact even thick fuel flows into a canistor side from the breather passage, to eliminate providing a second pressure sensitive valve as before. Air-fuel ratio fluctuation can be suppressed by adjusting an air-fuel ratio feedback correction factor FAF instead of purge restriction.
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