| 摘要 |
PURPOSE:To expand power air-fuel ratio region in high speed rotation zone by providing a control means for opening a valve unit interposed in an auxiliary fuel path provided bypassing a nozzle portion opening to an intake path when the opening of a throttle valve is larger than a set value. CONSTITUTION:A variable Venturi type carbureter has a suction piston moved to or away from a Venturi fixing portion 3 provided upstream of a throttle valve in an intake path 1. A jet needle 28 provided integrally with the suction piston is loosely fitted in nozzle portions 11A, 11B provided in a fuel path 15. Also, said carbureter has an auxiliary fuel path 33 bypassing the nozzle portion 11A and branching from the fuel path 15, and a valve unit 41 is interposed in said path 33. The valve unit 41 is controlled to open when the opening of the throttle valve is larger than a set valve or when it is less than the set value and intake negative pressure is less than a set value. Thus, power air-fuel ratio region in high speed rotation zone is expanded. |
