| 摘要 |
PURPOSE:To prevent abrupt torque rise at the time of acceleration and to thereby obtain a comfortable feeling of acceleration, by connecting a pipe communicated with the atmosphere to a vacuum chamber of a suction piston, and providing, in said pipe communicated with the atmosphere, a vacuum-operated value that is opened when the suction vacuum is dropped rapidly. CONSTITUTION:A variable venturi carburetor of this invention comprises a suction piston 3 that is moved to the left when the negative pressure produced at a venturi portion 8 by the air flow through an intake passage is transmitted into a vacuum chamber 18 via a port 18, and fuel is ejected into the intake passage 2 from a nozzle 23 at a rate corresponding to the opening area between a needle 4 and a metering jet 21 formed integrally with the suction piston 3. Here, the vacuum chamber 15 is formed to be capable of communicating with the atmosphere via a vacuum-operated valve 25 and a pipe 24 communicated with the atmosphere, and the vacuum-operated valve 25 is designed to open against the force of a spring 31 when the suction vacuum in the intake passage 2 on the downstream side of a throttle valve 6 is dropped rapidly. By thus introducing the atmosphere into the vacuum chamber 15, it is enabled to carry out abrupt leftward movement of the piston 3. |
