| 摘要 |
PURPOSE:To improve engine accelerating performance of a carburetor, by communicating a space formed above the surface of fuel in an acceleration well with a port formed in the wall of a bore of an intake passage near an air valve, and locating the air valve such that it is positioned on the downstream side of the air valve when it is fully opened but positioned on the upstream side of the air valve when its opening is larger than a prescribed angle. CONSTITUTION:A space 7 formed above the surface of fuel in an acceleration well 4 is communicated with a port 16 formed in the bore 10 for an intake passage of an air valve 1, and the port 16 is located such that it is positioned on the downstream side of the air valve 1 when it is fully opened but positioned on the upstream side of the air valve 1 when its opening is greater than a prescribed angle. With such an arrangement, when the air valve is fully opened for acceleration of an engine, fuel in the acceleration well 4 is ejected temporarily from the port 16 to compensate delay of fuel supply from a main nozzle 3 and to thereby prevent air-fuel mixture from becoming too lean. On the other hand, when the valve is fully opened for accelerating the engine at a low speed, the port 16 is located on the downstream side of the air valve 1, the amount of fuel ejected from an acceleration nozzle 12 is kept small. However, since the port 16 is located on the upstream side of the air valve 1 during high- speed operation of the engine, atmospheric pressure is actuated to the surface of fuel in the well 4, so that an amount of fuel corresponding to the capacity of the acceleration well 4 is discharged therefrom. Therefore, it is enabled to improve the accelerating performance of the engine. |
