| 摘要 |
PROBLEM TO BE SOLVED: To maintain an exhaust emission control performance in a satisfactory condition by suppressing changes of an air fuel ratio when purge cut and purge restart and done and ensure a purge treatment amount by controlling a purge rate of evaporated fuel properly while suppressing worsening of the exhaust emission control performance and drivability due to changes of the air fuel ratio. SOLUTION: When purge is done for the first time after engine operation is started, a purge rate when preceding purge is completed is used as a target purge rate if purge-inhibiting time is shorter than a predetermined value and is set in such a way that an initial value of the target purge rate is reduced and is gradually increased if the purge inhibit time exceeds the predetermined value. When purge at the second time and after is restated (or purge cut conditions are satisfied), drive duty of a purge control vale by the influence amount due to purge cut is increased and compensated by air fuel ratio feedback compensation coefficient if the drive duty of the purge control valve is changed not less than a predetermined value (10%).
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