| 摘要 |
PURPOSE:To enhance the water cooling effect of a cylinder block, by forming water jackets substantially along the entire length of cylinder bores, and making the thickness of inner walls of the water jackets substantially equal to that of outer walls of the water jackets. CONSTITUTION:In a cylinder portion 1 constituting the upper half of a cylinder block B, water jackets 6 are formed in teh manner of surrounding cylinder bores 3 excluding the wall portions located between adjacent cylinder bores 3. The water jackets 6 are formed along to cover substantially the entire length of the cylinder bores 3, and the thickness (di) of inner walls 11 of the water jackets 6 is made substantially equal to the thickness (do) of outer walls 12 of the water jackets 6. By employing such an arrangement, the cylinder portion 1 can be cooled substantially uniformly by water passed through the water jackets 6, so that the temperature distribution of the cylinder portion 1 can be made substan- tially uniform. |
