| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark ignition type internal combustion engine capable of securing engine output while a geometric compression ratio is a high compression ratio.SOLUTION: In the spark ignition type internal combustion engine, the geometric compression ratio of an engine body is set to be 14 or higher, an overlap period of an intake valve 8 and an exhaust valve 9 to be opened across a top dead center is set to be 35°CA or higher in a low speed high load region, a clearance between an upper surface 3a of a piston 3 at the top dead center and a lower surface 8a of the intake valve 8 in a valve closed state and a clearance between the upper surface 3a of the piston 3 at the top dead center and a lower surface 9a of the exhaust valve 9 in the valve closed state are set to be 5 mm or larger respectively, and a stroke S of the piston 3 is set, with a bore diameter of a cylinder C as B, to a length to be S≤0.977×B+18.2 mm. |
