| 摘要 |
PURPOSE:To reduce the resistance of suction and exhaust flow to be produced by an unbrella section by inclining the umbrella section against the axis. CONSTITUTION:The umbrella section 18b of a suction valve 18 is inclined by predetermined angle alpha against the axis 18a while inclined by predetermined angle beta for the exhaust valve 20. Consequently, upon opening of the valves 18, 20, the umbrella section 18b and the suction port 19, the umbrella section and the position of exhaust port 21 of exhaust valve 20 are shifted by the distance (S) to flow in suction air directly from the suction port 19 to the combustion chamber. While exhaust gas can flow out directly from the combustion chamber to the exhaust port 21 to reduce the flow resistance resulting in improvement of suction/exhaust efficiency. |
