| 摘要 |
PROBLEM TO BE SOLVED: To effectively cool a heating part by extending an intake port wall in the direction crossing a cylinder head to form a partitioning wall, and guiding cooling water in the direction orthogonal to the crank axial line. SOLUTION: A second intake port 62 is formed shorter than a first intake port 61, its intermediate part is linearly extended in the direction orthogonal to a crank axial line so as to cross under the first intake port 61, and the downstream opening end is continued and connected orthogonally to a second intake valve port. The first and second intake ports 61, 62 are provided on the upper wall of cylinder head CH in two vertical stages to shorten the crank axial line directional lateral width of the whole intake port 6. The intake port wall W of the intake port 6 consisting of two stages of the first and second intake ports 61, 62 forms a vertical guide wall orthogonal to the crank axial line on the upper wall of the cylinder head CH to guide the flow of the cooling water carried in a cooling water passage 10.
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