【正文】 ach piston is connected to the crankshaft by means of a link known as a connecting rod. Other types of reciprocating engines substitutes an eccentric, an inclined plate ,or a cam mechanism for the crankshaft .The piston engine has no crankshaft or connecting rods. Engine Components The typical automotive engine is made up of several essential ponents. These ponents are designed to provide efficient and reliable engine operation .The basic ponents in a fourcycle automotive engine include the following: （ 1） Cylinder block. （ 2） Crankshaft. （ 3） Pitons. （ 4） Piston rings. （ 5） Connecting rods. （ 6） Piston pin. （ 7） Cylinder head. （ 8） Valve train(includes valves and valve operating mechanism). 天津職業(yè)技術師范大學 2021屆本科生畢業(yè)設計 Engine construction Cylinder Block The cylinder block is cast in one piece. Usually, this is the largest and the most plicated single piece of metal in the automobile. The cylinder block is a plicated casting made of gray iron (cast iron ) or aluminum. It contains the cylinders and the water jackets that surround them. To make the cylinder block, a sand form called a mold is made. Then molten metal is poured into the mold. When the metal has cooled the sand mold is broken up and removed. This leaves the tough cylinderblock casting. The casting. The casting is then cleaned and machined to make the finished block. Cylinder blocks for diesel engines are very similar to those for sparkignition engines. The basic difference is that the dieselengine cylinder block is heavier and stronger. This is because of the higher pressures developed in the dieselengine cylinders. Several engines have aluminum cylinder blocks. Aluminum is relatively light metal, weighing much less than cast iron. also ,aluminum conducts heat more rapidly than cast soft to use as cylinder wall material. It wears too rapidly. Therefore, aluminum cylinder blocks must have castiron cylinder liners or be cast from an aluminum alloy that has silicon particles in it. Some manufactures make an aluminum cylinder block that does not have cylinder liners, or sleeves. Instead ,the aluminum is loaded with silicon particles. Silicon is a very hard material. After the cylinder block is cast, the cylinders are honed. Then they are treated with a chemical that etches eats away, the surface aluminum. This leaves only the silicon particles exposed. the pist. The cylinder block is cast in one piece. Usually, this is the largest and the most plicated single piece of metal in the automobile. The cylinder block is a plicated casting made of gray iron (cast iron ) or aluminum. It contains the cylinders and the water jackets that surround them. To make the cylinder block, a sand form called a mold is made. Then molten metal is poured into the mold. When the metal has cooled the sand mold is broken up and removed. This leaves the tough cylinderblock casting. The casting. The casting is then cleaned and machined to make the finished block. Cylinder blocks for diesel engines are very similar to those for sparkignition engines. The basic difference is that the dieselengine cylinder block is heavier and 天津職業(yè)技術師范大學 2021屆本科生畢業(yè)設計 stronger. This is because of the higher pressures developed in the dieselengine cylinders. Several engines have aluminum cylinder blocks. Aluminum is relatively light metal, weighing much less than cast iron. also ,aluminum conducts heat more rapidly than cast soft to use as cylinder wall material. It wears too rapidly. Therefore, aluminum cylinder blocks must have castiron cylinder liners or be cast from an aluminum alloy that has silicon particles in it. Some manufactures make an aluminum cylinder block that does not have cylinder