汽车构造英文版.docx

1、汽车构造英文版CHAPTER 1 AUTOMOTIVE BASICS1.1 Principal ComponentsTodays average car contains more than 15,000 separate, individual parts that must work together. These parts can grouped into four major categories: engine, body, chassis and electrical equipment. 1.2 EngineThe engine acts as the power unit.

2、The internal combustion engine is most common: this obtains its power by burning a liquid fuel inside the engine cylinder. There are two types of engine :gasoline(also called a spark-ignition engine) and diesel(also called a compression-ignition engine).Both engines are called heat engines; the burn

3、ing fuel generates heat which causes the gas inside the cylinder to increase its pressure and supply power to rotate a shaft connected to the transmission.1.3 BodyAn automobile body is a sheet metal shell with windows, doors, a hood, and a trunk deck built into it. It provides a protective covering

4、for the engine, passengers, and cargo. The body is designed to keep passengers safe and comfortable. The body styling provides an attractive, colorful, modern appearance for the vehicle.1.4 ChassisThe chassis is an assembly of those systems that are the major operating part of a vehicle. The chassis

5、 includes the transmission, suspension, steering, and brake systems.Transmission systems conveys the drive to the wheels. The main components are clutch, gearbox, driveshaft, final drive, and differential.Suspension absorbs the road shocks.Steering controls the direction of the movement.Brake slows

6、down the vehicle.1.5 Electrical EquipmentThe electrical system supplies electricity for the ignition, horn, lights, heater, and starter. The electricity level is maintained by a charging circuit. This circuit consists of the battery, alternator (or generator). The battery stores electricity. The alt

7、ernator changes the engines mechanical energy into electrical energy and recharges the battery.New WordsPrincipal component 主要部件 category 种类，类型body 车身 chassis 底盘layout 布置 power unit 动力装置internal combustion engine 内燃机 cylinder 汽缸gasoline 汽油 spark 火ignition 点燃，点火 diesel 柴油机compression 压缩 shaft 轴transm

8、ission 传动系 sheet metal 金属板shell 外壳 hood （发动机）罩trunk deck 行李舱盖 cargo 货物styling 样式 assembly 总成，装配suspension 悬挂，悬置 shock 冲击steering 转向，操纵 brake 刹车，制动器clutch 离合器 gearbox 变速器 driveshaft 传动轴 final drive 主减速器，后桥 differential 差速器 slow down （使）慢下来，减速horn 喇叭 starter 起动机 charge 充电 alternator 交流发电机Review Questi

9、ons 1. List the main parts of an automobile?2. What are the common types of a vehicle according to body styling?3. Which systems does a chassis include and what are the main functions of the chassis?4. Why are suspension systems used on vehicles?CHAPTER2 INTERNAL COMBUSTION ENGINE2.1 principle of op

10、eration 2.1.1 Engine and power Engine is used to produce power. The chemical energy in fuel is converted to heat by the burning of the fuel at a controlled rate. This process is called combustion. If engine combustion occurs with the power chamber. ,the engine is called internal combustion engine. I

11、f combustion takes place outside the cylinder, the engine is called an external combustion engine. Engine used in automobiles are internal combustion heat engines. Heat energy released in the combustion chamber raises the temperature of the combustion gases with the chamber. The increase in gas temp

12、erature 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.2.1.2 Engine Terms Linking the piston by a connecting rod to a cran

13、kshaft 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 ;an inlet valve allows the new mixtur

14、e to enter at the right time and an exhaust valve lets out the burnt gas after the gas has done its job. Engine terms are : TDC(Top Dead Center):the position of the crank and piston when the piston is farther away from the crankshaft. BDC(Bottom Dead Center):the position of the crank and piston when

15、 the piston is nearest to the crankshaft. Stroke : the distance between BDC and TDC; stroke is controlled by the crankshaft. Bore : the internal diameter of the cylinder. Swept volume : the volume between TDC and BDC. Engine capacity : this is the swept volume of all the cylinder e.g. a four-stroke

16、having a capacity of two liters(2000cm) has a cylinder swept volume of 50cm. Clearance volume: the volume of the space above the piston when it is at TDC. Compression ratio = (swept vol + clearance vol)(clearance vol) Two-stroke : a power stroke every revolution of the crank. Four-stroke : a power s

17、troke every other revolution of the crank.2.1.3 The Four-stroke Spark-ignition Engine Cycle The spark-ignition engine is an internal-combustion engine with externally supplied in ignition, which converts the energy contained in the fuel to kinetic energy. The cycle of operations is spread over four

18、piston strokes. To complete the full cycle it takes two revolutions of the crankshaft.The operating strokes are : This stroke introduces a mixture of atomized gasoline and air into the cylinder. The stroke starts when the piston moves downward from a position near the top of the cylinder. As the pis

19、ton moves downward, a vacuum, or low-pressure area, is created. During the intake stroke, one of the ports is opened by moving the inlet valve. The exhaust valve remains tightly closed.Compression strokeAs the piston moves upward to compress the fuel mixture trapped in the cylinder, the valves are c

20、losed tightly. This compression action heats the air/fuel mixture slightly and confines it within a small area called the combustion chamber.Power strokeJust before the piston reaches the top of its compression stroke, an electrical spark is introduced from a spark plug screwed into the cylinder hea

21、d.The spark ignites the compressed, heated mixture of fuel and air in the combustion chamber to cause rapid burning. The burning fuel produces intense heat that causes rapid expansion of the gases compressed within the cylinder. This pressure forces the piston downward. The downward stroke turns the

22、 crankshaft with great force.Exhaust strokeJust before the bottom of the power stroke, the exhaust valve opens. This allows the piston, as it moves upward, to push the hot, burned gases out through the open exhaust valve.Then, just before the piston reaches its highest point, the exhaust valve close

23、s and the inlet valve opens. As the piston reaches the highest point in the cylinder, known as TDC, it starts back down again. Thus, one cycle ends and another begins immediately.2.1.4 Engine Overall Mechanics The engine has hundreds of other parts . The major parts of engine are engine block , engi

24、ne heads, pistons, connecting rods, crankshaft and valves. The other parts are joined to make systems. These systems are the fuel system, intake system, ignition system, cooling system, lubrication system and exhaust system. Each of these systems has a definite function. These systems will discussed

25、 in detail later. NEW WORDPiston 活塞 Connecting rod 连杆Crankshaft 曲轴 Power stoke 活塞行程Expel 排出 Valve 气阀inlet(intake) valve 进气阀 exhaust valve 排气阀term 术语 TDC 上止点BDC 下止点 Bore 缸径swept volume 有效容积 engine capacity 发动机排量clearance volume 余隙容积,燃烧室容积 compression ratio 压缩比revolution 旋转,转数 every other 每隔一个cycle 循环

26、 spread over 分布,遍及intake stroke 进气行程 compression stroke 压缩行程knock 敲缸,敲打 exhaust stroke 排气行程engine block 发动机缸体 lubrication 润滑2.2 Engine Block and Cylinder Head2.2.1 Engine BlockThe engine block is the basic frame of the engine. All other engine parts either fit inside it or fasten to it. It holds the

27、 cylinders, water jackets, and oil galleries. The engine block also holds the crankshaft, which fastens to the bottom of the block. The camshaft also fits inside the block, except on overhead-cam engines (OHC). In most cars, this block is made of gray iron, or an alloy (mixture) of gray iron and oth

28、er metals, such as nickel or chromium. Engine blocks are castings.Some engine blocks, especially those in smaller cars, are made of cast aluminum. This metal is much lighter than iron. However, iron wears better than aluminum. Therefore, the cylinders in most aluminum engines are lined with iron or

29、steel sleeves. These sleeves are called cylinder sleeves. Some engine blocks are made entirely of aluminum.2.2.2 Cylinder HeadThe 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. The most common cy

30、linder head types are the hemi, wedge, and semi-hemi. All three of these terms refer to the shape of the engines combustion chamber. The cylinder head carries the valves, valve springs and the rockers on the rocker shaft, this part of the valve gear being worked by the push-rods. Sometimes the camsh

31、aft is fitted directly into the cylinder head and operates on the valves without rockers. This is called an overhead camshaft arrangement. Like the cylinder block, the head is made from either cast iron or aluminum alloy.2.2.3 GasketThe cylinder head is attached to the block with high-tensile steel

32、studs. The joint between the block and the head must be gas-tight so that none of the burning mixture can escape. This is achieved by using cylinder head gasket. This is a sandwich gasket, i.e. a sheet of asbestos between two sheets of copper, both these materials being able to withstand the high temperature and pressures within the engine.2.2.4 Oil Pan