| 摘要 |
PROBLEM TO BE SOLVED: To improve drivability by restraining a fluctuation in engine output in a cruise operation state by increasingly correcting a suction air quantity by a prescribed quantity when engine output by correction of an ignition timing delay is judged comparatively large. SOLUTION: A judgment is made on whether or not it is lean operation time (S10), and when it is YES, a judgment is made on whether or not SOx sticks by a prescribed quantity or more to an NOx absorber (S12). When it is YES, a judgment is made on whether or not a vehicle is put in a cruise operation state (S16), and when it is YES, a judgment is made on whether or not a crank angle speed variationΔME is not less than a prescribed value SM (S16). When it is NO, that is, when judged that a fluctuation in engine output is comparatively small, the ignition timing is corrected so as to delay by a prescribed quantity (S18). While, when it is YES, that is, when judged that a fluctuation in engine output by correction of an ignition timing delay is comparatively large, a preset third map is searched from an engine speed and intake pipe inside absolute pressure to calculate an increasing correction quantity of a suction air quantity to open a bypass air control valve by a corresponding quantity (S20).
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