| 摘要 |
PURPOSE:To suppress the lowering of torque by communicating two suction passages with each other through a comparatively large through hole provided in the vicinity of a combustion chamber, and causing one suction passage to function as a suction resonance box buring the low-speed driving of an engine. CONSTITUTION:During the low-speed revolution of an engine, a pressure governing valve 31 is switched so that the negative pressure within a negative pressure tank 31 is introduced into a negative pressure chamber 27 of a diaphragm device 25 by an output signal of a logical operation circuit 35 which receives an output signal from a speed sensor 36, and a suction control valve 22 is opened by the left-hand movement of a diaphragm 26. Accordingly, suction air, the quantity of which has been measured by a carbureter throttle valve, passes only through a second suction passage 9 and is sucked up into a combustion chamber 5. Upon this occasion, since a through hole 38 is provided between first and second suction passages 8 and 9, suction air which has directly advanced toward the combustion chamber 5 during the closure of a suction air valve 7, changes its direction and flows into the first suction air passage 8. Simultaneously with the opening of the suction air valve 7, suction air blows into the combustion chamber 5 to thereby prevent the lowering of the torque. |
