| 摘要 |
PURPOSE:To obtain a more proper air-fuel ratio, by separating a control system for an air control valve and a control system for a fuel control valve from each other, and controlling the air control valve to correct the pressure difference between the venturi pressure and a required setting pressure. CONSTITUTION:An air control valve 2 is designed to be moved vertically by turning a screw shaft 12 by a driving means such as a servomotor, while a fuel control valve is so designed that the amount of fuel supplied from a float chamber 5 to a fuel outlet port 10 is controlled by a solenoid valve 13. The air control valve controls a servomotor 11 to correct the deviation between a required setting pressure and the venturi vacuum that is increased with increasing of the opening of a throttle valve 3. As for fuel control, fuel supply rate is controlled by pre-calculating the basic duty-ratio of the solenoid valve 13 and correcting the duty-ratio according to the operational mode of an engine and the conditions of the atmosphere. |
