| 摘要 |
PURPOSE:To avoid the over-richness of air-fuel ratio at rapid acceleration or deceleration due to vaporization of a flow of fuel deposited on a wall surface of a suction pipe or the like by computing a quantity of the fuel vaporized from the wall surface according to a change in quantity of the fuel flow deposited on the wall surface, and controlling a bypass air quantity according to the result of computation. CONSTITUTION:An engine operational condition is detected by means a. A fuel flow deposited on a wall surface of a suction pipe or the like is predicted by means b according to the engine operational condition detected by the means a. A quantity of vaporization of the fuel flow deposited on the wall surface and a control value for changing a suction air quantity according to the fuel quantity vaporized from the wall surface are computed by means c according to a change in the fuel flow predicted by the means b. Then, a suction air quantity flowing in a bypass passage bypassing a throttle valve is controlled by means d according to the control value computed by the means c. Accordingly, when the operational condition is so changed as to accelerate the vaporization of the fuel flow deposited on the wall surface (e.g., at rapid acceleration), the bypass air quantity is increased to avoid the over-richness of air-fuel ratio.
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