| 摘要 |
PROBLEM TO BE SOLVED: To provide a four-cycle engine in which an intake port shape with small intake resistance is formed by using simple mold structure without increase in the number of parts, and to provide a small-sized four-cycle engine surely preventing accumulation of liquified fuel to suppress combustion failure of combustion gas or generation of unburned gas. SOLUTION: The four-cycle engine has an intake port base part 4a formed integrally with a cylinder head 4, and an intake port forming member 7 cooperative with the intake port base part 4a so as to form an intake port 5. The intake port 5 has a shape, in which an area of a cross-section orthogonal to the center line 5a of the intake port 5 is roughly the same from an intake-side opening to a communicating part with a combustion chamber 13, and the center line 5a of the intake port 5 and an intake valve stem 6a form an angleθon an intake valve 6 side which is larger than a right angle. COPYRIGHT: (C)2007,JPO&INPIT
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