| 摘要 |
PURPOSE:To check the occurrence of knocking at the whole driving range, by installing an on-off valve in a suction port provided with a suction valve at the side where a lag in closing time is made larger, while making the on-off valve so as to be actuated from close to open according to an increase in supercharging pressure. CONSTITUTION:A low-speed range, for example, below about 1,600r.p.m. in an engine speed, an on-off valve 22 comes to 'full-close', cutting off a first suction port 3A. Therefore, suction air passes through a second suction port 3B alone and flows in a tangential direction toward an inner wall of a combustion chamber 19 so that a swirl is largely formed inside the combustion chamber 19, making combustion ever so better. When the engine speed increases and internal pressure in a suction pipe reaches, for example, more than 200mm.Hg, the on-off valve 22 gets opening as well as when the supercharging pressure reaches, for example, 300mm.Hg, it comes to full-open, making the first suction port 3A go into operation. |
