汽车专业的毕业设计.docVIP

专业外文翻译材料 系 别 南京机电学院 专 业 汽车检测与维修技术 班 级 汽修 1003 学生姓名 岳祥龙 学 号 1101513240 指导教师 张锦龙 2013年4月 目 录 第一部分 专业外文翻译材料原文…………………………………………………1 第二部分 专业外文翻译材料译文…………………………………………12 参考文献…………………………………………………………………………21 专业外文翻译材料原文 Engines Cylinder Block The cylinder block is the largest past of the engine.Its upper section carries the cylinders and pistons.Normally,the lower section forms the crankcase,and supports the crankshaft.It can be cast in one piece from grey iron.Or it can be alloyed with other metals like nickel or chromium. The iron casting process begins by making up the shapes of what will become water jackets and cylinders as sand cores which are fitted into moulds.The stops there parts becoming solid iron during casting.Molten iron is poured into sand moulds that are formed by patterns in the shape of the block. After casting,core sand is removed through holes in the sides and ends,leaving spaces for the cooling and lubricant passages.There holes are sealed with plugs.The casting is then machined.Cylinders are bored and finished,surfaces smoothed,holes drilled and threads cut.All cylinder blocks are made with ribs,web and fillets to provide rigidity but also keep weight to a minimum. Cylinder Block Construction As more manufacturers try to make vehicles lighter and more fuel efficient,more and more engine blocks are being cast from aluminium.A block made of aluminium alloy is lighter than if it were made of cast iron.So if two engines are generating the same power,the alloy version would have a better weight-to-power ratio than the cast alloy version.Aluminium alloy blocks are made by various casting processes,including pressure casting.Another method is gravity casting,where the molten metal is poured into molds. Cast iron liners are usually used in the cylinders of aluminium blocks,and sometimes in cast-iron blocks.Some sleeves are cast into the block.Grooves on the outsi