汽车实用英语(已整理)

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1、It is well-known that the automobile is composed of four sections such as engine, chassis, body and electrical system.众所周知，汽车都由发动机、底盘、车身以及电气系统四部分组成。The engine which is called the heart of a vehicle is used to supply power for an automobile. It includes the fuel, lubricating, cooling, ignition and st

2、arting systems. Generally, an automobile is operated by internal combustion engine. The internal combustion engine burns fuel within the cylinders and converts the expanding force of the combustion or explosion into rotary force used to propel the vehicle.发动机是汽车的心脏，向汽车提供动力。它包含有燃料系统、润滑系统、冷却系统、点火系统和起动

3、系统。汽车一般采用内燃发动机。内燃发动机在汽缸里燃烧燃料将内燃所产生的膨胀力转变成旋转力，用以推动车辆前进。The chassis is a framework used to assemble auto components on it. The chassis itself is divided into four systems like transmission system, suspension system, steering system and brake system.底盘是一个用以总装汽车部件的框架。底盘本身可以分成四个系统，即传动系统、悬架系统、转向系统和制动系统。Th

4、e transmission system applies to the components needed to transfer the drive from the engine to the road wheels. The main components are clutch, gearbox, drive shaft, final drive and differential.传动系统运用所需部件将发动机产生的动力传递到车轮。它的主要部件有离合器、变速器、传动轴、后桥和差速器。The primary purpose of the suspension system is to in

5、crease strength and durability of components and to meet customers requirements for riding comfort and driving safety. In automobile suspension, the major component is springs. The springs used on todays vehicles are engineered in a wide variety of types, sizes, rates and capacities. Spring types in

6、clude leaf springs, coil springs and torsion bars. Springs are paired off on vehicles in various combinations, and are attached to vehicle by different mounting techniques.悬架系统的主要目的是提高零部件的强度和寿命，并满足顾客对车辆乘坐舒适性和驾驶安全性的需求。汽车悬架上的主要部件是弹簧。在当今车辆上使用的弹簧被设计制造成许多不同的型号、大小、标准及负载。弹簧类型包括钢板弹簧、螺旋弹簧和扭力弹簧。弹簧以各种组合形式在车辆上配

7、套使用，并用不同的装配技术将弹簧装在车辆上。The function of the steering system is to provide the driver with a means for controlling the direction of the vehicle as it moves. The steering system consists of steering wheel, steering shaft, worm, gear sector, pitman arm, drag link, steering knuckle arm, king pin, steering

8、 arms, tie rod, front axle and steering knuckle. They enable the car to change the direction by means of turning and moving forth and back. 转向系统的用途是在驾驶员的操纵下控制汽车行驶的方向。转向系统包括转向盘、转向轴、蜗杆、扇形齿轮、转向摇臂、直拉杆、转向节臂、主销、转向臂、转向横拉杆、前轴和转向节。这些零部件前后移动或转动，可以使汽车改变运动方向。The automobile brake system is a friction device to c

9、hange power into heat. When the brakes are applied, they convert the power of momentum of the moving vehicle kinetic energy) into heat by means of friction, thus retarding the motion of the vehicle. Structurally, an automotive brake system contains these major parts like brake drum, brake shoe, brak

10、e lining, etc. Functionally, an automotive brake system can be divided into wheel brake mechanism and parking brake mechanism. 汽车制动系统是一种将动力转变为热量的摩擦装置。当使用制动器时，制动器通过摩擦将行驶车辆的动量力转变成热量，从而使车辆运动停滞。从结构上讲，汽车制动系含有几个主要部件，如制动鼓、制动蹄片、制动器摩擦衬片等。从功能上讲，汽车制动系可分为行车制动机构和停车制动机构。The automobile body serves the obvious purp

11、ose of providing shelter, comfort and protection for the occupants. The body is generally classified into four sections: the front, the rear, the top and the underbody. These sections can further fall into a lot of assemblies and parts, such as the hood, the fenders, the roof panels, the door, the i

12、nstrument panel, the bumpers and the luggage compartment. 车身的基本功能就是向乘员提供保护，使其乘坐舒适并保证安全。车身一般分为四个部分:车前部、车后部、车顶部和车下部。这些部分可以进一步分为许多的分总成和部件，如发动机盖板、挡泥板、车身顶板、车门、仪表板、汽车保险杠和行李箱。The electric system supplies lighting and driving power for the automobile. It cranks me engine for starting. It supplies the high-v

13、oltage surges that ignite the compressed air-fuel mixture in the combustion chambers. The electric system includes the battery, generator, starting system, ignition system, lighting system, horn system, radio and other devices. 电气系统向汽车提供照明与驱动电力。它能起动发动机、提供高压电脉冲点燃燃烧室中空气和燃油的高压混合气等。电气系统包括电池、发电机、起动系统、点火系

14、统、照明系统、喇叭、收音机以及其他装置。The auto description above seems to conclude that though automobiles are quite different in design, they are basically similar in structure. 综上所述，尽管汽车的设计变化很大，然而汽车的构造基本上是一样的。Text Four-stage-engine OperationThere are various types of engines such as electric motors, steam engines a

15、nd internal combustion engines. But, the internal combustion engine seems to be the one most commonly used in the automotive field. According to the fuel energy used, internal combustion engines are further divided into gasoline engines, kerosene engines, diesel engines, etc.四行程发动机工作过程 发动机有各种各样的类型，如

16、电动机、蒸汽机和内燃机。但是，在汽车领域里内燃机似乎是用得最为普遍的发动机。根据所用燃料，内燃机还可分为汽油机、煤油机、柴油机等。The internal combustion engine, as its name indicates, burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle. The actions taking place in the engine cylinder can

17、 be classified into four stages, or strokes. Stroke refers to piston movement; a stroke occurs when the piston moves from one limiting position to the other. The upper limit of piston movement is called TDC (top dead center) .The lower limit of piston movement is called BDC (bottom dead center). A s

18、troke is piston movement from TDC to BDC or from BDC to TDC. In other words, the piston completes a stroke each time it changes its direction of motion. 顾名思义，内燃发动机是在汽缸里燃烧燃料，将内燃的膨胀力转变成推动汽车前进的旋转力。发动机汽缸内的工作过程可以分为四个过程或行程。(冲程)行程是指活塞的运动，即活塞从某一限定位置到另一限定位置的运动。活塞运动的上限称为TDC(上止点)，下限称为BDC(下止点)。一个行程就是活塞从上止点到下止点，

19、或从下止点到上止点的运动。换句话说，活塞每完成一个行程，就改变一次其运动的方向。Where the entire cycle of events in the cylinder requires four strokes (or two crankshaft revolutions), the engine is called a four-stroke-cycle engine. The four-stroke-cycle engine is also called the Otto cycle engine, in honor of the German engineer, Dr. Nik

20、olaus Otto , who first applied the principle in 1876. The four piston strokes are intake, compression, power and exhaust.Intake stroke. On the intake stroke, the intake valve has opened, the piston is movingdownward, and a mixture of air and vaporized gasoline is entering the cylinder through the va

21、lve port. The mixture of air and vaporized gasoline is delivered to the cylinder by the fuel system and carburetor.Compression stroke. After the piston reaches BDC, or the lower limit of its travel, it begins to move upward. As this happens, the intake valve closes. The exhaust valve is also closed,

22、 so that the cylinder is sealed. As the piston moves upward (pushed now by the revolving crankshaft and connecting rod), the air-fuel mixture is compressed. By the time the piston reaches TDC, the mixture has been compressed to as little as one-tenth of its original volume, or even less. When the ai

23、r-fuel mixture is compressed, not only does the pressure in the cylinder to up, but the temperature of the mixture also increases.Power stroke. As the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug. The ignition system delivers a high-voltage surge of e

24、lectricity to the spark plug to produce the spark. The spark ignites the air-fuel mixture. It now begins to bum very rapidly, and the cylinder pressure increases to as much as 35MPa or even more. This terrific push against the piston forces it downward, and a power impulse is transmitted through the

25、 connecting rod to the crankpin on the crankshaft. The crankshaft is rotated as the piston is pushed down by the pressure above it.Exhaust stroke. As the piston reaches BDC again, the exhaust valve opens. Now, as the piston moves up on the exhaust stroke, it forces the burned gases out of the cylind

26、er through the exhaust-valve port. Then, when the piston reaches TDC, the exhaust valve closes and the intake valve opens. Now, a fresh charge of air-fuel mixture will be drawn in to the cylinder as the piston moves down again toward BDC.This four stroke cycle of piston within the cylinder is repeat

27、ed time and again to put the vehicle forward. 发动机汽缸中的全部工作过程分为四个冲程的(即曲轴旋转两周的)，叫做四冲程循环发动机，或四循环发动机。为纪念德国工程师尼科拉斯、奥托搏士于1876年首次运用四行程循环原理，四行程循环发动机也叫奥托循环发动机。发动机的四个活塞行程是进气、压缩、做功和排气。 进气冲程:在进气行程中，进气门打开，活塞向下移动，可燃混合气通过进气门进入汽缸。适当浓度的可燃混合气是由燃料系统和化油器提供的。 压缩冲程:在活塞到达下止点时或者是活塞下限时，活塞开始向上运动。同时，进气门关闭，排气门也关闭，所以这时的汽缸是封闭的。当活

28、塞向上运动时(这时是由转动的曲轴和连杆推动活塞)，可燃混合气被压缩。当活塞到达上止点时，可燃混合气被压缩到有原体积的十分之下甚至更少。当油气混合燃料被压缩时，不仅汽缸里的压力上升，可燃混合气的温度也随之增加了。 做功冲程:当活塞到达压缩行程的上止点时，火花塞产生电火花。电火花是由点火系统向火花塞提供高压电脉冲而产生的。电火花点燃可燃混合气。可燃混合气开始发生剧烈燃烧，汽缸内压力达到3-5兆帕，甚至更高。作用于活塞上强大的推动力推动活塞向下运动，并将这一推力通过连杆传到曲轴上的连杆轴颈上。因此，当活塞受压向下运动时，推动曲轴转动。 排气冲程:当活塞再一次到达下止点时，排气门打开。同时，活塞向上移

29、动，将废气经排气门排出汽缸。随后，活塞达到上止点，排气门关闭，进气门打开。当活塞又一次向下移动到达下止点时，新的可燃混合气被吸入汽缸。 汽缸活塞的四个冲程不断重复，推动着汽车前进。The Power Mechanism of the EngineIn a reciprocating engine, the power mechanism is called the crankshaft and connecting rod assembly. In this assembly, all of the major units such as the engine crankcase and cy

30、linder block, the piston and connecting rod (see Figure 3.1), the crankshaft and flywheel work together to convert thermal energy into mechanical energy used to drive the vehicle.The engine crankcase and block are usually cast into one piece and therefore can be seemed as the largest and most intric

31、ate piece of metal in automobile. They are usually made of high-grade cast alloy iron to improve wear characteristics of the cylinder. This major unit must be strong and rigid enough to withstand any bending or distortion.The piston converts the potential engines of the fuel into the kinetic energy

32、that turns the crankshaft. The piston is a cylindrical shaped hollow part that moves up and down inside the engines cylinder. The piston is composed of piston head, piston rings, piston lands, piston skirt and piston pin hole. The piston head or crown is the top surface against which the explosive f

33、orce is exerted. It may be flat, concave, and convex or any one of a great variety of shapes to promote turbulence or help control combustion. In some application, a narrow groove is cut into the piston above the top ring to serve as a heat dam to reduce the amount of heat reaching the top ring. The

34、 piston rings carried in the ring groove are of two basic types: compression rings and off-control ring. The upper ring or rings are to prevent compression leakage; the lower ring or rings control the amount of oil being deposited on the cylinder wall. The lower groove or grooves often have holes or

35、 slots in the bottom of the grooves to permits oil drainage from behind the rings. The piston lands are parts of piston between the ring grooves. The lands provide a seating surface for the sides of piston rings.The main section of a piston is known as the skirts. It forms a bearing area in contact

36、with the cylinder wall. The piston pinhole in the piston also serves as a bearing for the piston pin, which is used to connect the connecting rod. In addition, because pistons operate under exceedingly difficult mechanical and thermal conditions, piston must be strong enough to stand the force of th

37、e expansion, yet light enough to avoid excessive inertia forces when their direction of travel is reversed twice each revolution. Piston must be able to withstand the heat from the burning air-fuel mixture, plus the heat generated by friction.The connecting rod is attached to the crankshaft at one e

38、nd (big end) and to the piston at the other end (small end). In operation, the connecting rod is subjected to both gas pressure and inertia loads, and therefore, it must be adequately strong and rigid and light in weight as well. So they are generally fabricated from high quality steel. The connecti

39、ng rod is in form of a bar with ring shaped heads at its end. They are composed of connecting rod small end, connecting rod shank, connecting rod big end, connecting rod cap, and connecting rod bearing half shells. Shank of the connecting rod is provided with an I-cross section to give the rod maxim

40、um rigidity with the minimum of weight. The big end of the rod is split so that it can be connected to the crankshaft. To avoid misplacing the rod caps during assembly, the connecting rods and their mating caps are marked on one side with serial numbers, starting with the first rod from the radiator

41、, to identify their location in the engine.Some connecting rods have an oil spurt hole in the yoke or at the cap-mating surface to provide cylinder wall lubrication. The small end of the connecting rod is attached to the piston by a piston pin. In some cases the small end of the rod is clamped to th

42、e pin or has a bushing in it to allow the pin and rod oscillation. In other designs the pin is bolted to the rod. Connecting rods are usually drilled to provide lubrication to the piston pin and also to spray oil into the bottom of the piston for piston cooling on some designs.The crankshaft serves

43、to change the reciprocating motion of the piston into rotary motion and handles the entire power output. The periodic gas and inertia forces taken by the crankshaft may cause it to suffer wear and bending and tensional strains. The crankshaft therefore must be adequately strong and wear-resistant. S

44、o the crankshaft is either forged from a high quality steel or cast in a high-strong iron. The crankshaft is actually made up of various parts such as main bearing journals, rod journal, crank arm bearing, counter-balanced weight and flywheel end. The crankshaft revolves in bearings located in the e

45、ngine crankcase, but the number of bearings used usually depends on the number of cylinders in the engine and the design of the engine. Mechanically, a crankshaft without special balanced weight would have severe vibration when revolving. In order to reduce or eliminate such vibration, it must be pr

46、ovided with counter balanced weights that extend radially from the crankshaft centerline in the opposite direction of the crank arms. In that way, the forces acting on the crankshaft are balanced and vibration is reduced. The rod journals are bored hollow in order to reduce the crankshaft inertia. D

47、rilled diagonally through the crank arms are oil holes to supply oil to the rod journals.The flywheel is a relatively heavy metal wheel, which is firmly attached to the crankshaft. Its function is to help the engine to run smoothly by absorbing some of the energy during the power stroke and releasin

48、g it during the other strokes.In the front face of the flywheel, there is a shallow indentation used to determine the position of the piston in the first cylinder. When this indentation is aligned with a special hole provided in the bell housing, the piston is at top dead center (TDC) or indicates t

49、he start of fuel injection into the first cylinder. The flywheels of some engines also carry marks indicating the serial numbers of the cylinders where the compression occurs. The flywheel marks and indentation are used for setting the valve and ignition systems relative to prescribed positions of t

50、he crankshaft.In conclusion, the connecting rod and crankshaft mechanism of the engine is composed of various units, and each of these units has its own functions in producing power for vehicles.发动机的能量转换装置 曲柄连杆机构就是往复式发动机的能量转换装置。曲柄连杆机构主要的组件，如曲轴箱和缸体、连杆和活塞、曲轴和飞轮，协同工作把热能转化为机械能，从而推动汽车行驶。 通常发动机的曲轴箱和缸体浇铸为了

51、体。曲轴箱缸体是汽车中最大、最复杂的金属件，一般由优质合金铸铁制成，以增强其耐磨性。(曲轴箱缸体)这个主要组件必须有足够的强度和刚度，承受所有弯曲和扭曲变形。 活塞把燃料的内能(化学能)转化为动能使曲轴旋转。活塞是圆柱形的中空的机件，在汽缸内上下运动。活塞由顶部、活塞环、环槽岸部、裙部和活塞销组成。活塞顶部或冠都是活塞的上表面，(燃烧所产生的)爆炸作用力就作用于此。活塞顶部可以做成平的、凹的、凸的或是能够促进涡流帮助燃烧的任何形状。某些发动机中，最上道活塞环的上方开出一窄槽作为绝热槽，以减少热量的传递。位于活塞环槽内的活塞环分为气环和油环。上面的(气环)防止漏气，下面的(油环)可以控制积聚在汽

52、缸壁的机油量。活塞环槽内通常钻有油孔或油槽，以从活塞环后面泄油。活塞环槽之间的部位称为槽岸，槽岸为活塞环侧面提供了艾承面。 活塞最主要的部位是裙部，裙部形成活塞与缸壁的接触支承面。活塞销座支撑活塞销，而活塞销连接活塞和连杆。此外，由于活塞在非常苛刻的机械条件和很高的温度下工作，其强度必须足以承受膨胀作用力。一个工作循环活塞上下运动两次，因此活塞自重应尽可能轻以减小惯性作用。活塞应当能够承受燃烧混合气和摩擦热量。 连杆一端 (大头)与曲轴相连，另一端 (小头)和活塞配合。连杆工作时受到气体压力和惯性作用，因此必须有足够的强度和刚度，质量尽可能轻。连杆一般由优质钢制成，其杆身两端为环形。连杆由小头

53、、杆身、大头、连杆盖和轴瓦组成。连杆杆身断面为工字型，这样可以同时获得最大刚度和最小质量。连杆大头一般为剖分式，以便和曲轴相连。为防止装配时装错连杆盖，在连杆和与其相配合的连杆盖的某一侧标有序号，从靠水箱侧为第一缸，以确认各缸的位置。 一些连杆在大头轴头处或在连杆盖配合面上钻有喷油孔润滑汽缸壁。连杆小头通过活塞销与活塞相连。一些发动机的连杆小头与活塞销夹在一起，即连杆小头有衬套，使活塞销和连杆一起运动。而在另一些设计中用螺栓连接活塞销和连杆。通常连杆上钻出油道润滑活塞销，有些设计中连杆上的油道也向活塞底部喷油实现冷却。 曲轴用于把活塞的往复运动转化为旋转运动并控制全部动力输出。曲轴所受到的周期

54、性的气体压力和惯性力导致曲轴磨损、产生弯曲和扭转变形。因此曲轴应当有足够的强度和耐磨。曲轴由优质钢锻造或通过高强度铸铁铸造而成。事实上曲轴由主轴颈、连杆轴颈、曲柄臂轴承、平衡块和飞轮端这些主要部件所组成。曲轴在位于曲轴箱内的主轴承上旋转，所使用的主轴承数量取决于发动机汽缸数和发动机的设计。如果没有专门的平衡块，曲轴在旋转时会产生剧烈的振动。为了减少甚至消除振动，在曲轴中心线的延长线上与曲柄臂相反方向配有平衡块。这样，作用于曲轴的作用力得到了平衡，减少了振动。连杆轴颈内部锐空目的是减少曲轴惯性。穿过曲柄臂斜向钻出的油孔提供连杆轴颈的润滑。 飞轮是一个相当重的金属轮盘，飞轮与曲轴紧相连。它的作用是

55、在做功行程吸收能量，在其他工作行程释放能量，从而有助于发动机平稳工作。 在飞轮前断面有一浅的缺口，用来确定一缸活塞位置。当缺口与飞轮壳体上的小孔对齐时，一缸活塞位于上止点或表明一缸开始喷油。有些发动机的飞轮标有在压缩行程的汽缸序号。飞轮上的记号和缺口用来调整与曲轴特定位置相关的配气机构和点火系统。 总之，发动机曲柄连杆机构由各个不同的组件构成，在产生汽车动力时每个组件具有特定的功能。Valves and Valve TrainThe valve gear of an internal combustion engine provides timely admission of the fres

56、h charge into the cylinders and exhaust of spent gases from them. For this purpose the valves at definite moments open and close the intake and exhaust ports in the cylinder head, through which the cylinders communicate with the intake and exhaust manifold.The valve gear is composed of timing gears,

57、 a camshaft, tappets, valves, spring with fasteners and valve guides.The timing gears in most engines are housed in a special case fitted at the front end of the engine. These are necessary to transmit rotation from the crankshaft to the camshaft, fuel injection pump shaft, and to oil pump and other

58、 mechanisms.The gears are made of steel and use helical teeth to reduce noise.Camshafts function is to open the engine valves positively and timely, in a definite sequence, and to control their closing against the return action of the valve springs. The shaft is made integral with its cams and beari

59、ng journals. Each cam controls a single valve, either intake or exhaust. In some automobile engines, the camshaft is made integral with fuel pump eccentric wheel and oil pump drive gear. The camshaft bearings are lubricated with oil supplied under pressure from the main gallery in the cylinder block

60、.The tappets serve to transmit the force from the camshaft to the push rods. The tappets are small cylindrical bores receiving the push rods. They are made of cast iron or steel and located in the guides, which may be made integral with the cylinder block or removable as in the engine. When the engi

61、nes operate, the tappets continuously rotate about their axes for uniform wear. The rotation is ensured by a convex surface of their bottoms and a slanted surface of the cams.The push rods transmits the force from the tappets to the rocker and are made as steel stems with hardened tips or duralumin

62、tubes with spherical steel tips press-fitted at. both ends. The push rod tips bear against the tappet hollow at one end against the spherical surface of rocker adjusting screw at other.The rockers transmit the force from the push rod to the valve. The rockers are made from steel and are installed on

63、 a hollow fulcrum. A bronze bush is press fitted into the rocker hole to reduce friction. The hollow fulcrum is supported by standards on the cylinder head. Endplay of the rocker is prevented by a coil spring.The rocker arm is a bell crank made of steel. At the middle of the rocker arm, there is a b

64、oss with a bore into which is pressed the bushing. A hardened curved pad is provided on the end of the rocker where it contacts the valve stem tip, while a threaded hole is machined in its other end to receive the adjusting screw used to set the valve clearance, the clearance between the rocker cont

65、act pad and the valve stem tip, so that the valve will be tightly pressed against its seat when hot. The rocker arm freely oscillates about the rocker-arm shaft supported by a series of pedestals or brackets, which are bolted to the top deck of the cylinder head.An engine valve is a device designed to open a passage when moving in one direction and to close it when moving in the opposite direction. Each cylinder of a four-stroke-cycle diesel or gasoune engine is commonly equipped with an intake valve and an exhaust valve. The pur