| 摘要 |
PURPOSE:To keep off a sudden air-fuel ratio variation at the latter half period of acceleration, by making a bleed air quantity decrease by force in time of changing a sensor signal after getting the bleed air increased at acceleration, in case of a carburetor which feedback-controls an air-fuel ratio by an exhaust sensor. CONSTITUTION:In time of normal conditions, a controller 2 actuates a bleed air control valve 22 of a carburetor 24 with a signal out of an exhaust sensor 4 and performs feedback control over an air-fuel ratio. When acceleration is detected by an actuation sensor 6 of a throttle valve 16, an opening position of the control valve 22 is immediately made to be shifted to a state that a bleed air quantity increases. On the other hand, at a fuel feed system, an accelerating increment corresponding to the throttle valve takes place. After continuation of the acceleration, air-fuel ratio control by means of an oxygen sensor 4 takes place till the oxygen sensor 4 outputs a lean signal, and when the lean signal enters for the first time, the control valve 22 is selected, decreasing the bleed air by force, thus a sudden air-fuel ratio variation to lean mixture is prevented from occurring. |
