(1) Today’s average car contains more than 15,000 separate, individual parts that must work together.These parts can be grouped into four major categories: body, engine, chassis and electrical equipment 。
当今的车辆一般都由15000多个分散、独立且相互配合的零部件组成。这些零部件主要分为四类：车身、发动机、底盘和电气设备。
(2) The body is designed to keep passengers safe and comfortable. The body styling provides an
attractive, colorful, modern appearance for the vehicle.
车身的设计要保证乘客安全舒适。车身的款式使得汽车看起来漂亮迷人、彩斑斓、时
尚前卫。
1) Engines used in automobiles are internal combustion heat engines. They convert the chemical energy of the gasoline into heat within a power chamber that is called a combustion
chamber.Heat energy released in the combustion chamber raises the temperature of the combustion gases within the chamber. The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power.
2) Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn. The power stroke "uses up" the gas, so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture: this control of gas movement is the duty of the valves; (Page 10)
1) The engine block is the basic frame of the engine. All other engine parts either fit inside it or fasten to it. It holds the cylinders, water jackets, and oil galleries. The engine block also
holds the
crankshaft, which fastens to the bottom of the block. (Page 13)
缸体是发动机的基体。发动机其它的部件都安装或固定在缸体上，包括气缸、水套和油
道，以及固定在缸体底部的曲轴等。
2) Cylinder sleeves are used in engine blocks to provide a hard wearing material for pistons and piston rings. The block can be made of one kind of iron that is light and easy to cast while the sleeves uses another that is better able to stand up wear and tear. There are two main types
of sleeves: dry and wet. (Page 10)
缸体中的气缸套为活塞和活塞环提供了一种坚硬耐磨的材料。缸体可以采用某种重量轻且易铸造的铁来制造，而缸套使用的却是另一种更加耐磨损的材料制
58汽车成。主要有两种类型的气缸套：干缸套和湿缸套。
3) The cylinder head fastens to the top of the block,just as a roof fits over a house. The underside forms the combustion chamber with the top of the piston. In-line engines of light vehicles have just one cylinder head for all cylinders; larger in-line engines
can have two or more. (Page 14)
气缸盖安装在缸体的顶部，就像安在房子上的屋顶一样。缸盖的下方和活塞顶部形成燃烧室。轻型车上使用的直列发动机，所有气缸仅有一个气缸盖，较大的直列发动机有两个或更多缸盖。
4) The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and runs down into the pan.Thus, there is constant circulation of oil between thepan and the working pats of the engine. (Page 15)
润滑系的机油泵从油底壳抽出机油，并把机油输送给发动机的所有工作部件。机油从油底壳流进流出。因而在油底壳和发动机的工作部件之间就有机油定向循环流动。
1) Most pistons are made from cast aluminum. Thepiston, through the connecting rod, tran
sfers to the crankshaft the force created by the burning fuel mixture. This force turns the crankshaft. (Page 17)
大多数活塞由铝铸造而成。通过连杆的作用，活塞把可燃混合气燃烧产生的力传递给曲轴，带动曲轴旋转。
2) In diesel engines, the combustion chamber may be formed totally or in part in the piston crown, depending on method of injection. (Page 18)
柴油机发动机根据喷油方法不同，活塞头部可以形成全部燃烧室，也可以是燃烧室的一部分．
3) In modern engines, each piston has three rings. (Piston in older engines sometimes had four rings, or even five.)The inside surface of the ring fits in the groove on the piston. The ring's outside surface presses against the cylinder walls.
在新型发动机上，每个活塞有三个活塞环。（在老式发动机上，每个活塞有四个甚至五个活塞环）环的内侧装在活塞的环槽里，环的外表面紧压在气缸壁上。
The cam is an egg-shaped piece of metal on a shaft that rotates in coordination with the crankshaft. The metal shaft, called the camshaft, typically has individual cams for each valve in the engine. As the camshaft rotates, the lobe, or high spot of the cam, pushes against parts connected to the stem of the valve. This action forces the valve to move downward. This action could open an inlet valve for an intake stroke, or open an exhaust valve for an exhaust stroke.
凸轮是一个蛋形的金属块，它安装在同曲轴协调运转的一根轴上，该轴称为凸轮轴，其上有同发动机每一个气门对应的凸轮。当凸轮轴旋转时，凸轮的最高点，也就是凸圆，推动连接气门杆的部件，使得气门向下运动，在进气冲程打开进气门，在排气冲程打开排气门。
In this arrangement, the cam lobes push against round metal cylinders called cam follower. As the lobe of the cam comes up under the cam follower, it pushes the cam follower upward (away from the camshaft). The cam follower rides against a push rod, which pushes against a rocker arm. The rocker arm pivots on a shaft through its center. As one side of the rocker arm moves up, the other side moves down, just like a seesaw. The downward-moving side of the rocker arm pushes on the
valve stem to open the valve. （p27）
在这种方案中，凸轮凸圆推动圆形的金属筒，也就是挺柱。凸轮凸圆运动到挺柱下方时，推动挺柱远离凸轮轴向上运动。挺柱带着推杆，推杆推动摇臂，摇臂绕摇臂轴的中心转动。摇臂的一端升起，另一端就落下，这类似于跷跷板。摇臂向下运动的一端推动气门杆打开气门。
When the engine runs in compression stroke and power stroke, the valves must close tightly on their seats to produce a gas-tight seal and thus prevent the gases escaping from the combustion chamber. If the valves do not close fully the engine will not develop full power. Also the valve heads will be liable to be burnt by the passing hot gases, and there is the likelihood of the piston crown touching an open valve, which can seriously damage the
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