| 摘要 |
<p>A piston (1) includes a cavity (5) defined by a curved recessed portion (5a) formed on a crown surface in a manner such that a surface of the curved recessed portion extends along a tumble flow produced during an intake stroke, and a weakening portion (6) that is disposed in the cavity. The weakening portion, for example, is disposed on the crown surface of the piston (1) so as to occupy the portion of the crown surface that includes substantially a center portion of the piston (1). The weakening portion (6) reduces the strength of tumble flow produced by the gas flowing into a combustion chamber when the intake valves are opened.</p> |
