| 摘要 |
PURPOSE:To give a difference to the inflow quantity of an air-fuel mixture out of each suction valve port as well as to produce a swirl of the mixture inside a combustion chamber, by making both these suction valve ports different in a bore each. CONSTITUTION:When an engine's suction stroke starts, first of all, a second suction valve opens whereby an air-fuel mixture flows much into a combustion chamber 6 from a large diametral second suction valve port 92 alone. Therefore, the inflow mixture is given a swirl in a direction toward an exhaust port 10 through the peripheral part of a spark plug 12 from the second suction valve port 92 in the light of being subject to the influence of a fact that a second branch port 132 points to a tangential direction of the peripheral wall of the combustion chamber 6. Next, a first suction valve 18, opens and therefore the air-fuel mixture flows into the combustion chamber 6 from a small diametral first suction valve port 9 as well, whereby it is joined with the mixture that has previously produced the swirl. |
