| 摘要 |
PURPOSE:To improve distribution of fuel as well as to reduce flow resistance by forming a cross sectional shape of each of branch parts so that the radius of the inner circumferential part is larger than the radius of the outer circumferential part when a branch middle part of a port is cut in perpendicular to the flow direction. CONSTITUTION:At least an intake port 5 which opens in a combustion chamber 4 of an engine is formed by a common part 51, a branch middle part 54 and each of branch parts 52 and 53. Also, a tip end part of a fuel injection valve 3 is inserted into an escape groove 9 communicated with the intake port 5. In this case, when the intake port 5 is cut in perpendicular to the flow direction of intake air at least at the branch middle part 54, a cross sectional shape of each of the branch parts 52 and 53 is formed so that the radius Ra of the inner circumferential part is in the shape of a semicircle larger than the radius Rb of the outer circumferential part. And each of the branch parts 52 and 53 is formed so that the common part 51 in the shape of a circle is gradually separated in the half-cut state. By this, flow resistance f the intake air is reduced and distribution of fuel is improved. |
