| 摘要 |
PURPOSE:To stabilize an improve an air-fuel ratio controlling property upon opening and closing of a valve by a method wherein a needle valve is held in a bouncing condition when the tapered needle valve provided so as to be capable of adjusting the amount of an air bleed is fully opened. CONSTITUTION:There are provided an oxygen density senser 3 in an exhaust gas path 2, a vacuum sensor in a suction air path 4 and a cooling water temperature detecting sensor or the like in a jacket 6 respectively while the taper needle valve 11 is controlled by a control circuit 9 through a step motor 11 based on the signals of respective sensors. When the valve 11 is bounced continuously under the fully closed condition of the taper needle valve 11, a constant flow amount may be secured in accordance with the bound. In this case, the minimum air blled amount, capable of preventing the inflow of fuel into air bleed paths 13, 14 under fully closed condition substantially, may be secured. |
