| 摘要 |
PURPOSE:To improve volumetric efficiency by providing projections, inserted in an intake port and an exhaust port respectively when a piston is in the top dead center, on the top surface of the piston. CONSTITUTION:Projection parts 36, 37, provided on the top surface of a piston 20, are inserted respectively in an intake port 13 and an exhaust port 14 at the end of a process of compression for a cylinder 3 of supercharge. This insertion reduces inner capacity of the intake port 13 and the exhaust port 14. Therefore, capacity of a gap when the piston 20 is at its top dead center is reduced by capacity as much as that of both projection parts 36, 37 inserted in the intake port 13 and the exhaust port 14, and the volumetric capacity is improved. |
