| 摘要 |
PURPOSE:To provide the optimum air-fuel ratio control constantly by obtaining information on fuel flow amount from fuel flow at the time of low pressure before fuel is supplied to a fuel injection pump for controlling a throttle valve to obtain the optimum air-fuel ratio as well as controlling the air-fuel ratio in a closed loop. CONSTITUTION:When an accelerator pedal is stepped in, the fuel amount in a fuel injection pump 6 is increased via a control rack 9, and the differential pressure before and after a variable throttle valve 3 in a fuel passage 12 is increased. The change of this differential pressure is detected by a diaphragm 7, and the opening degree of a throttle valve 13 is increased via a damper 8. At this stage, the amount of suction air is measured by an air flow meter 11 provided near a Venturi part 33 in a suction air passage 10. The variable throttle valve 3 is adjusted to be opened in accordance with the measured result, and the differential pressure before and after the variable throttle valve 3 is weakened to converge to a fixed value. This construction permits to obtain the optimum air-fuel ratio during the said driving by stopping the throttle valve 13 at a certain opening. |
