| 摘要 |
PURPOSE:To obtain an optimum air-fuel ratio and as well to miniaturize a carburettor, by sliding a piston having a metering needle and provided in one side of the carburettor, under venturi-vacuum. CONSTITUTION:Negative pressure from a negative pressure take-out part 22b which is formed in an invariable venturi 3 downstream of a choke valve 5 is introduced through a passage 22 into a space above a piston 8 which is lidable in a chamber 7 formed in one side part of a carburettor body 1. The piston 8 is pushed downward under the balance between upper and lower springs 9, 10, and a needle 14 adapted to be inserted into a metering jet is secured to the lower section of the piston 8 by means of a retaining spring 17. When the throttle valve 6 is opened to increase the amount of intake-air, the negative pressure of the venturi 3 is increased, resulting in the upward movement of the piston 8, and therefore, the needle 14 is moved upward by a height (1), thereby optimum fuel is fed from the venturi 3 through a nozzle 19a in a passage 19. |
