| 摘要 |
PURPOSE:To enable a stable low-speed fuel supply and throttle valve operation to be carried out by providing a pressure receiving chamber of intake negative pressure between main-and sub-throttle valves both of which move integrally up and down, and after a low-speed fuel controlled by the opening of a throttle valve is mixed with air and introduced into a pressure receiving chamber, supplying it into an intake pipe. CONSTITUTION:A subthrottle valve 6 is provided to a main throttle valve 5 which is moved up and down by a wire 11 via a pressure receiving chamber 7, and the main- and sub-throttle valves 5, 6 are integrally moved up and down. On the upper side of the subthrottle valve 6, the regulating part 8A of a low-speed fuel port 9A is provided, and at the time of low-opening of the throttle valve, low-speed fuel together with the atmospheric bleed air in a chamber 3 is supplied into the pressure receiving chamber 7. The mixture inside the pressure receiving chamber 7 is taken in from a hole 6c. Since the low-speed fuel once enters the pressure receiving chamber being a stable mixing chamber, the supply of low-speed fuel is stabilized, and the subthrottle valve 6 is sucked back by the negative pressure in the pressure receiving chamber and further the up-and-down movement thereof can be made smooth by the lubricating action due to fuel.
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