| 摘要 |
PURPOSE:To uniformize the flow of an air-fuel mixture in time of low speed, low load running of an engine, by making a distance from a suction valve axis to the top upstream end of a diaphragm as nearly 1.2 time as larger than the diameter of a cylindrical outlet throat of a vortex part. CONSTITUTION:In time of low speed, low load running of an engine, there is produced a swirly current inside a vortex part B by dint of an air-fuel mixture guided at a spot between a diaphragm 12 and side wall surfaces 17 and 15. A part of the air-fuel mixture being fed into an inlet passage part A is uniformized in its flow direction at a spot between the side wall surface 17 of the inlet passage part A and the diaphragm 12 so that there is produced a powerful swirly current inside the vortex part B. To uniformize the flow direction, it is ample enough to lengthen the diaphragm 12 alone but if it is too long, resistance of the flow in a suction port 6 grows large when a rotary valve 25 opens a branch passage 24. Accordingly, in order to obtain such a powerful swirly current as securing a highly charging efficiency, it is desireable that a distance L be made as nearly 1.2 D. |
