| 摘要 |
PURPOSE:To ensure a satisfactory swirl effect over various operating ranges, by providing a control valve at the bifurcate point between primary and secondary intake-air ports, and by opening and closing this control valve in accordance with the operating condition of an engine to preferentially feed intake-air from the primary intake-port. CONSTITUTION:Upon idling operation the negative-pressure in an intake-air pipe is highest, and therefore, an actuator 11 closes a control valve 10, and a valve element 18 in the control valve 10 is inclined to slightly open a primary intake- air port 4 alone. Therefore, mixture from a carburettor 9 is deflected in the direction tangential to an engine cylinder by the valve element 4 and is, therefore, led to the outlet side of the primary intake-air port 4, so that the mixture is introduced into the cylinder at an increased flow rate in accordance with the opening degree of the valve element. Meanwhile, upon partial load operating the control valve 10 is rotated in its opening direction gradually in accordance with the decreasing negative pressure of intake-air. Therefore, the inclination of the valve element 18 is gradually decreased to increase the opening degree of the primary intake-air port 5 while the secondary intake-air port 5 is started to be opened, thereby it is possible to create swirl in accordance with loads. |
