| 摘要 |
PURPOSE:To improve the combustion in high-load range by forming the depth of a pair of diffusion parts which use a valve recess in common into uniform value and specifying the ratio between the depth and the sectional area of an injection port. CONSTITUTION:Positioned below a suction valve and an exhaust valve at the piston top-edge part 4, the diffusion parts 7A and 8A consisting of a pair of circular concaved parts having the diameter larger than that of the both valves are formed largely at the center. A groove-shaped trench part 10A which is contiguous to the both diffusion parts and whose one edge extends to the undersurface of an injection port 21 communicating to an eddy-current chamber 20 is formed on the axis of symmetry to the diffusion parts 7A and 8A. The depth of the diffusion part is formed uniform, and the ratio S/L between the depth L and the sectional area S of the injection port is made 50 or less. Therefore, the flow of flame to the diffusion part can be secured sufficiently even in high-load range, and combustion can be improved. |
