| 摘要 |
PURPOSE:To maintain good driving performance of an engine, by preventing mixture from becoming too lean in medium and high-speed operational ranges of the engine and keeping the air-fuel ratio at a required value by providing a main bleed air intake port in a venturi. CONSTITUTION:An intake passage 11 having an intake port 10 opened at the portion of a large venturi 3 where the diameter is smallest is connected to a main air bleed jet 8, and the intake passage 11 is connected to a proper position of a suction passage 1 located on the upstream side of the venturi 3 via a port 12 consisting of a small-diameter jet. With such an arrangement, air bubbles are formed in an emulsion pipe 9 at the time of low-speed operation of an engine since the velocity of air flow at the venturi is low, so that atomization of fuel supplied from a main nozzle 7 is promoted. As the engine speed is increased from low to medium and further to high, the air bleeding effect is reduced and the mixture becomes gradually rich. Further, fuel is drawn out from the passage 11 by the function of high vacuum acted at the intake port 10. In the above arrangement, the air bleeding effect is made controllable by changing the diameters of the intake passage 11 and the port 12. |
