| 摘要 |
PURPOSE:To correct to make the air/fuel ratio rich by communicating the negative pressure lead-in path opening to a suction path at the upper straem than a throttle valve with an air bleed path while releasing a portion of bleed air to the suction path under heavy load high speed running. CONSTITUTION:Under heavy load high speed running where a throttle valve 7 will be high opening, secondary throttle valve 10 will open to inject fuel through secondary fuel nozzle 28 into small Venturi 9 in secondary suction path 3. Here negative pressure in large Venturi 4 in main suction path 2 is relatively high to flow a portion of air from an air bleed path 19 through negative pressure lead-in path 40 into large Venturi tube 4 thus to reduce the amount of air to be injected through an air jet 20 into an air bleed tube 12 and to increase the fuel injection by that amount to make rich. When providing an atmosphere responsive valve at the down stream from the coupling position of negative pressure lead-in path 40 and air bleed path 19, air-fuel ratio is prevented from going excessively rich. |
