| 摘要 |
PURPOSE:To obtain air-fuel ratio at starting to a rich state, by communicating an air passage to the upstream side of a bypass passage of a throttle valve and communicating the air passage to a fuel feed nozzle. CONSTITUTION:A bypass passage 9, communicating the upstream side to the downstream side of a valve 3, is fromed in a carburetor passage 2, simultaneously an open-close valve 10 and starting fuel nozzle 11 are provided in the passage 9. Futher one end of an air passage 15 is opened between an opening 14, at the upstream side, and the open-close valve 10 in the bypass passage 9, and the other end of this passage 15 is opened to the side of a mixing tube 4. At starting, the open-close valve 10 is opened, and intake negative pressure in the downstream of the throttle valve 3 acts upon the starting fuel nozzle 11 in accordance with opening of the throttle valve 3. The intake negative pressure is more or less decreased by the air passage 15, then flow speed of air in the bypass passage 9 is decreased, though the amount of fuel for starting is decreased, a relatively rich mixture can be obtained from a nozzle 5. |
