| 摘要 |
PROBLEM TO BE SOLVED: To provide an engine structure which can minimize an influence to the shape of a cylinder bore caused by thermal deformation (chevron deformation) due to the difference between the thermal expansion amount of a cylinder block and that of a cylinder head generated mainly at the time of actual operation of an engine. SOLUTION: The engine structure is provided with the cylinder block 2 and the cylinder head 3 which is fixed to the head-attachment surface 2a by a head bolt 5. The cylinder block 2 has the cylinder bore 6, a water jacket 7 and an exterior wall part 9. The water jacket 7 is formed so that it surrounds the cylinder bore 6, and the water jacket 7 is formed between a cylinder part 8 and the exterior wall part 9, which contains a bottom part 9a and a side wall part 9b. The bottom part 9a is a part extended from the outer peripheral surface 8c of the cylinder part 8 to the outside, and the side wall part 9b is provided by being extended from the bottom part 9a to the head-attachment surface 2a side. The side wall part 9b has a rigidity-degradation part 20 used for degrading its flexural rigidity. COPYRIGHT: (C)2009,JPO&INPIT
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