| 摘要 |
PURPOSE:To equalize all cylinder bores finally set due to thermal expansion of high loading by reducing gradually the cylinder bore measured in cold engine status from its portion near the bottom dead point of a piston to another portion near the top dead point. CONSTITUTION:The bore of a cylinder 2 of a cylinder block 1 is formed so as to be reduced gradually and upwardly from B1 at the portion 2b near the top dead point 2b to Bu at the portion 2a near the bottom dead point 2a. Notwithstanding the difference of expansion due to thermal difference between an upper portion of the cylinder and its lower portion, the difference being generated during high loading, any portions of the cylinder bore can be made equal during high loading when the cylinder bores of an upper portion and a lower portion at a room temperature are determined in consideration of the thermal difference and the thermal expansion coefficient of the material of the cylinder. Consequently, engine noise due to piston slap can be decreased. |
