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汽车实用英语(已整理)


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 calle

d the "heart" of a vehicle is used to supply power for an automobile. It includes the fuel, lubricating, cooling, ignition and starting 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。

The 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 increase 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 today's vehicles are engineered in a wide variety of types, sizes, rates and capacities. Spring types include 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 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 change 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, brake 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 purpose 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 instrument 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-voltage 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。

Four-stage-engine Operation There are various types of engines such as electric motors, steam engines and 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。

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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 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 stroke 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,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. Nikolaus 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 moving downward, and a mixture of air and vaporized gasoline is entering the cylinder through the valve 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, 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 air-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 electricity 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 3~5MPa or even more. This terrific push against the piston forces it downward, and a power impulse is transmitted through the 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 cylinder 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 repeated 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 Engine In 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 cylinder 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 intricate 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 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 force 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 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 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 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 the 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 end (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 connecting 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 maximum 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, 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 the 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 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. So 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 engine 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 provided 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. Drilled 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 releasing 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 the 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 the 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、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 Train The valve gear of an internal combustion engine provides timely admission of the fresh 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, 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 mechanisms.The gears are made of steel and use helical teeth to reduce noise. Camshaft's 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 bearing 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. 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 engines 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 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 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 boss 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 contact 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 purpose of the intake valve is to allow the air fuel mixture or air to enter the cylinder. After the combustion process has been completed, the burned gases are permitted to escape from the cylinder though the exhaust valve. To obtain sufficient valve area, some automobiles have two intake valves and two exhaust valves. A valve consists of a head and stem. The valve head has a narrow chamfer of 45°or 30°referred to as valve face. The valve face fits tightly against the seat, which is achieved by grinding. For better engine breathing, the inlet valve has a larger diameter than the exhaust one. As the valves are not equally heated in the running engine, they are made from different materials. The inlet valves are made from chromium steel, the exhaust valves are of silchrome heat-resistant steel. The cylinder stem of the valve has a recess at the upper end for fastening the valve spring. The valve stems slide in the cast-iron or cerametallic valve guides.

The valve spring provides the force necessary to close the valve and hold it tightly against its seat. Some engines use two springs on each valve, which reduce the size of the springs, improves their reliability, and makes their operating conditions less arduous. Valve guide supports the valve stem and guides its movement so that the valve face remains perfectly concentric with the valve seat and fits it without any skewing. Replaceable valve guides are fabricated from cast iron or a cermets material and pressed in the cylinder head. To decrease oil penetration along the valve stem to the combustion chambers, the seating collars are fitted with rubber rings or the seats are provided with rubber caps. More uniform heating and wear of the valve are ensured with the valves rotating during the operation of the engine. In general, there are two ways of rotating: one is free rotate the other is positive rotate. As the valve is opened, spring is compressed and its increasing load causes the flexible washer to flatten out and force balls down their ramps against the resistance offered by their return springs .As the balls roll down, they turn through some angle the flexible washer, seating collar and valve spring together with the valve; when the valve is closed, the valve spring load decrease, the flexible washer deflects to acquire its initial conical shape and abutting against a shoulder in housing, releases the balls which are then forced by their coil springs to return to their starting position.
配气机构 内燃机的配气机构保证新鲜混合气可以适时进入汽缸,同时燃烧后的废气及时排出。为实现 这一目的,气门在一定的时刻打开和关闭汽缸盖上的进排气道,汽缸通过进排气歧管与进排气管相 沟通。 配气机构由正时齿轮、凸轮轴、挺柱、气门、带有锁紧装置的弹簧和气门导管组成。 大多数发动机的正时齿轮装在专门的壳体内,正时齿轮壳体位于发动机前端。必须使用正时 齿轮将曲轴的旋转传递到凸轮轴,驱动喷油泵轴、机油泵和其他的装置。正时齿轮由钢制成,采用 螺旋状齿以减少噪声。 凸轮轴的功用是按特定的顺序准确适时地打开气门并通过气门弹簧的回位作用控制气门的关 闭。凸轮轴与凸轮、轴颈制为一体。每个凸轮控制一个气门:进气门或排气门。有些汽车发动机的凸 轮轴也与驱动燃油泵的偏心轮和机油泵的驱动齿轮做成一体。缸体内主油道的机油在压力作用下到 达凸轮轴轴颈提供润滑。 挺柱用来把凸轮轴的作用力传递给推杆。挺柱为圆柱形小筒,里面插入推杆。挺柱材料为铸铁 或钢,定位于导管内,挺柱导管可以是与缸体一体的或者是可拆卸的。发动机工作时,为使磨损均 匀,挺柱总是绕其轴线旋转。挺柱的旋转是由挺柱凸起的下表面和凸轮倾斜面所保证的。 推杆将挺柱传来的推力传给摇臂。推杆由顶部淬火的钢柱或由两端压入配合的带球形钢头的硬 铝管制成。推杆的两端一头支撑在挺柱的空腔内,另一头与摇臂调整螺钉端的球形表面配合。 摇臂把推杆的作用力传递到气门。摇臂由钢制成,安装于空心的枢轴。摇臂空内装有青铜衬套 以减少摩擦。中空的摇臂轴通过支架固定于汽缸盖。摇臂上的螺旋弹簧防止产生轴向窜动。摇臂是 钢制的双臂杠杆。摇臂中部有一带孔的凸台,孔内压装有衬套。摇臂的一端是经过淬火的圆弧状长 臂,与气门杆尾端接触,而车有螺纹孔的另一端安装有调整螺钉,用来调整摇臂与气门杆尾端之间 的气门间隙,从而保证气门在受热后紧紧压在气门座上。摇臂可以绕摇臂轴自由摆动,摇臂轴通过 一系列支座支撑,支座用螺栓固定于汽缸盖上表面。 发动机气门向某一万向运动时开启-通道,而它向相反方向移动时则关闭此通道。四行程汽油机 或柴油机的每缸一般都装有进气门和排气门。%气门的作用是使空气燃油混合气进入汽缸。燃烧过 程完成后废气通过排气门排出汽缸。为了获得足够的充气面积,有些发动机采用两个进气门和两个 排气门。 气门由头部和杆身组成。气门头部相对于气门平面之间存在45。或30。的锥角。通过研磨使气 门平面与气门座紧密贴合。 为使发动机更好地换气,进气门(头部)直径大于排气门。在发动机工作时由于进、排气门受热 不均等,因此它们采用不同的材料制成。进气门采用铬钢,排气门采用耐热硅铬钢。 圆柱气门杆身的上部有一凹槽用来固定气门弹簧。气门杆身在铸铁或金属陶瓷气门导管内运 动。 气门弹簧提供气门关闭时所需要的作用力,保证气门与气门座紧密贴合。 有些发动机的每个气门装有两根弹簧,可以减小所使用的弹簧大小,增加可靠性,使工作更平 稳。 气门导管支撑气门杆身,对其运动起导向作用,以保证气门X闭时能准确地与气门座贴合而不 产生偏移。可拆卸式气门导管采用铸铁或金属陶瓷材料制成,压入汽缸盖上的(气门导管。 为防止机油从气门杆渗进燃烧室,在气门导管上装有橡胶环或橡胶皮碗。发动机工作时通过气 门的旋转可以使气门获得更均匀的受热和磨损。通常有两种实现气门旋转的方式:自由旋转和强制 旋转。

当气门开启时,弹簧被压缩,弹力增加,将弹性垫圈压平,迫使钢球克服回位弹簧的阻力沿斜 坡滚动。当钢球滚下时,带动弹性垫圈、气门弹簧与气门一起转过一个角度;当气门关闭时,气门弹 簧弹力减小,弹性垫圈变形为原来的圆锥状,支撑于壳体的支撑板,钢球在回位弹簧作用下回到原 来位置。

Engine Fuel System The fuel system is critical to operation. The system consists of the fuel tank, lines, pump, filter, carburetor, and injectors . Fuel Flow The fuel in the fuel tank is ready to be used when the engine needs it. The fuel pump draw fuel from the tank and sends it to the carburetor. The carburetor is to keep the fuel at the right air-fuel ratio. For a electric fuel-injected engine, the fuel is pressurized and sent to the fuel feed pipe, through a fuel filter, and into the fuel injectors. For a diesel fuel goes to the fuel injector pump, rather than to the carburetor, then to the fuel nozzles. Fuel Tank The fuel tank is used to store the fuel of engine needed. It is usually located in rear of the vehicle. The fuel tank is designed to fit around frame and to be protected from impacts. These are several baffles insides the fuel tank to restrict fuel movement during rapid starts and stops, cornering, and so on. The fuel cap on the fuel tank is used to keep the fuel from splashing out, release the vacuum created by the fuel removing, and prevent vapors from escaping directly into the atmosphere. The fuel levels are measured by a fuel-metering unit. One style of the unit has a hinged float inside the tank. As the float position changes with different levels of fuel, the needle position on the dashboard gauge changes. Fuel Pump Gasoline engine pump is either mechanical or electrical.

The mechanical fuel pump is used on many vehicles with carburetors and driven by the camshaft. There is a cam or an eccentric lobe on the camshaft. As the camshaft turns, the lobe lifts a lever up and down, causing a pumping action. Fuel is drawn from the tank by a vacuum and sent to the carburetor. Electrical fuel pump can be used instead of mechanical types. The types of the electrical fuel pumps employed include the bellow and the impeller or roller vane. In the bellows-type electrical fuel pump, a metal bellows is used instead of a diaphragm. It operates from the movement of the armature in the magnetic coil. The bellows is stretched and squeezed to cause the vacuum and pressure. The roller vane electrical fuel pumps are used on newer vehicles. As the electric motor turns an impeller, fuel is drawn in at the inlet port of the pump. It is pressurized and sent out the discharge port for delivery to the engine. The impeller at the inlet end serves as a vapor separator. A pressure relief valve keeps fuel pump pressure at a constant level. Fuel systems that have electrical fuel pumps and fuel injectors may use a fuel pressure regulator to keep the fuel pressure constant. Fuel Filters Fuel filers are used to stop any contamination from getting into the fuel system of both gasoline and diesel engines. The gasoline engines may have one or two filters in the fuel system. The first filter is usually placed inside the fuel tank to prevent large pieces of contaminant from damaging the fuel pump. The second one is an in-line type or an in-carburetor type used to filter out small dirt particles. Many diesel engines used in automotive applications have only one filter, which is called the primary filter. On some engines, a secondary filter is adopted and combined with primary one to build into a single filter. Carburetor Carburetors used on gasoline engine are designed to mix the air and fuel at the correct ratio. The most correct air-fuel ratio is 14.8 parts of air to 1 part of fuel. On the intake stoke, the piston moves down and the intake valve is opened, a vacuum is produced and causes air to be drawn or pulled into the engine. The air passes through the carburetor and venturi as it goes into the engine. A venturi is a streamlined restriction that partly closes the carburetor bore. The air entering the venturi is forced to speed up. The greater the velocity of air passed though the venturi, the greater the vacuum produced, and the more fuel is drawn in. The flow of air and fuel through the carburetor is controlled with a throttle plate. The throttle plate is placed below the venturi and connected to the acceleration pedal. As the driver's foot on the pedal is depressed, the throttle plate opens, and there is very little restriction of air and fuel. The load and speed is increased.
发动机燃料供给系统 燃料供给系统对于发动机的工作是至关重要的。燃料供给系统由燃油箱、燃油管、燃油 泵、燃油滤清器、化油器和喷油器组成。 燃油的流动 燃油箱可以提供发动机需要的燃油。燃油泵将燃油从油箱吸出并送至化油器。化油器保持合适 的空燃比的混合气。在电控燃油喷射式发动机中,燃油被加压送至输油管,经过燃油滤清器最终到 达喷油器。对于柴油机而言,燃油进入喷油泵而不是化油器,最后到达喷油器。 燃油箱 燃油箱用于储存发动机所需的燃油。燃油箱通常位于车辆后方。燃油箱安装在车架旁,保护油 箱不致受到冲击。燃油箱内有隔板,以减轻车辆起动、急刹车、转弯等情况下燃油的振荡。燃油箱 盖用来保持燃油不致溅出,释放因使用燃油造成的真空,防止燃油蒸汽泄入大气。 燃油平面的高低由燃油面指示装置来测量。 有一种类型的燃油面指示装置采用-浮子铰接到油箱 内。燃油面的高低会改变浮子的位置,仪表板上燃油表的指针的位置也随之发生了改变。 燃油泵 汽油机燃油泵为机械驱动式或电动式。 机械驱动燃油泵用于许多化油器式车辆,它由凸轮轴驱动。凸轮轴上有一凸轮或偏心轮。当凸 轮旋转时,(凸轮或偏心轮的)凸尖顶起拉杆上下运动,使燃油泵工作。燃油在真空作用下从油箱中 被吸入压送到化油器。 电动燃油泵可以代替机械式燃油泵。常用的电动燃油泵包括波纹管式和叶轮式。 在波纹管式电动燃油泵中,金属波纹管取代了膜片。金属波纹管在磁场线圈的电枢作用下工 作。波纹管被伸长、挤压,从而产生真空和压力。 叶轮式电动燃油泵用于新型车辆。电机带动叶轮转动,燃油被吸到燃油泵的进油道。燃油得 到加压,从油室到达发动机。进油端的叶轮起到油气分离器的作用。(燃油泵中的)卸压阀使燃油泵

压力保持一定。 采用电动燃油泵的燃料供给系统要使用燃油压力调节器来保证油压恒定。 燃油滤清器 燃油滤清器用来阻止汽油机或柴油机的燃油系统受到污染。 汽油机的燃油系统可以有一个或两个滤清器。第一个滤清器通常在燃油箱内,防止较大污物进 入损坏燃油泵。第二个滤清器串接在油路中或在化油器中,以去除较小污物微粒。 大多数车用柴油机只有一个燃油滤清器,称为初级滤清器。有些发动机将次级滤清器和初级滤 清器组合在一起。 化油器 汽油机中使用的化油器用来将空气和燃油以适当的比率混合,最佳空燃比为14.8:1。 在进气行程,活塞下行,进气门开启,产生真空使空气被吸进发动机。空气进入发动机要流经 化油器和文氏管(化油器喉管人 文氏管 (化油器喉管)部分关闭了化油器孔径,有效限制了气流。空气流经文氏管(化油器喉管) 时流速增加。流经文氏管(化油器喉管)的气流速度越快,产生的真空度就越大,吸进的燃油就越多。 通过化油器的空气和燃油的量是由节气门控制的。节气门位于喉管下方,与加速踏板(油门)相 连。当司机踩下油门时,节气门打开,空气和燃油的流动几乎不受限制,负荷和车速增加。

Engine Cooling System The purpose of the cooling system is to keep the engine at its most efficient operating temperature at all speeds under all driving conditions. As fuel is burned in the engine, about one-third of the heat energy in the fuel is converted into power. Another third goes out through the exhaust pipe unused, and the remaining third must be handled by the cooling system. This means that the engine can work effectively only when the heat energy is equally handled so as to keep the engine temperature in balance: So, the temperature is quite essential for an engine to produce power. No engine can work well without suitable operating temperatures. If the engine runs too hot, it may suffer from pre-ignition, while the air-fuel charge is ignited prematurely from excessive combustion chamber temperature. Viscosity of the oil circulating in an over heating engine is reduced. Hot oil also forms varnish and carbon deposits may be drawn into the combustion chamber where it increases HC emission. This also causes poor performance and premature wear, and may even result in engine damage. What's more, the behavior of the metals at excessively high temperature also differs from that at normal temperatures. If the engine runs too cold, the fuel will not vaporize properly. If liquid fuel reaches the cylinders, it will reduce lubrication by washing the oil from the cylinder walls and diluting the engine oil. This causes a loss of performance, an increase in HC emissions, and premature engine wear. For these reasons, a cooling system of some kind is necessary in any internal combustion engine. There are generally two different types of cooling system: water-cooling system and air-cooling system. Water-cooling system is common. The cooling medium, or coolant, in them is either water or some low-freezing liquid, called antifreeze. A water-cooling system consists of the engine water jacket, thermostat, water pump, radiator, radiator cap, fan, fan drive belt and necessary hoses. A water-cooling system means that water is used as a cooling agent to circulate through the engine to absorb the hot and carry it to the radiator for disposal. The engine is cooled mainly through heat transfer and heat dissipation. The heat generated by the mixture burned in engine must be transferred from the iron or aluminum cylinder to the water in the water jacket. The outside of the water jacket dissipates some of the heat to the air surrounding it, but most of the heat is carried by the cooling water to the radiator for dissipation. When the coolant temperature in the system reaches 90 ° C, the thermostat valve open fully, its slanted edge shutting off the shorter circuit so that the coolant circulates through the longer one: water-pump-cooling jacket -thermostat -radiator top -tank -radiator core -bottom tank -pump.

Water pumps have many designs, but most are the centrifugal type. They consist of a rotating fan, or impeller, and seldom are of the positive displacement type that uses gear or plungers. Many water pumps have a spring-loaded seal to avoid leakage of water around the pump shaft. Some V-type engines have a pump on each cylinder block. The radiator is a device designed to dissipate the heat which the coolant has absorb from the engine; it is constructed to hold a large amount of water in tubes or other passages which provide a large area in contact with the atmosphere. The radiator usually mainly consists of the radiator core, radiator bottom tank, and radiator top tank. Radiator cores are of two basic types, the fin and tube type (fins are placed around the tube to increase the area for radiating the heat) and of the ribbon cellular or honey comb type. The popular

fin and tube type of radiator core has the advantage of fewer soldered joints and is therefore a stronger construction. It consists of a series of parallel tubes extending from the upper to the lower tank. The honeycomb type core consists of a large number of narrow water passages made by soldering pairs of thin metal ribbons together along their edges. These tubes are separated by fins of metal ribbon, which help dissipate the heat. The radiator cap serves not only to prevent the coolant from splashing out the filler opening, but also to prevent evaporation of the coolant. The fan is designed to draw cooling air through the radiator core. The fan is usually mounted on an extension of the water pump shaft and is driven by a V-belt from a pulley mounted on the front end of the crankshaft. Usually the same belt drives the alternator, and belt tension is adjusted by swinging the alternator on its mounting. An air-cooling system contains a centrifugal fan, thermostat, fan drive belt, radiator fin, baffle plates, air control ring', etc. An air-cooling system means that air is used as a cooling agent to circulate through the engine to carry the heat away from the moving parts. When the engine is running, force air is directed over and through the fins to dissipate the heat. In order to regulate the engine temperature by controlling the volume of cooling air, a thermostat is installed inside the metal housing which encloses the engine. The thermostat unit is connected to an air control ring. As the engine becomes hotter, the control ring opens wider to admit more air, and closes when the engine is cold. With the ring closed, air circulation is restricted, and a cold engine warms up more rapidly. Rapid warm-up is one of the characteristics of air-cooled engine, since they do not have heat water in cylinder jackets and radiator. The engine cooling system actually is a temperature-regulation system. For a late-model engine, the cooling system must maintain a temperature that is high enough for efficient combustion but not so high that the engine will be damaged. The two jobs of the cooling system are to carry excess heat away from the engine and maintain uniform temperature through the engine. These requirements are very critical for an engine with electronic controls that must maintain precise air-fuel ratios for economy and emission control.
发动机冷却系统 冷却系统的功用是保证发动机在任何行车条件、任何车速保持最有效的工作温度。燃料在发动 机中燃烧,约三分之一的热能转化为动力,还有三分之一的热能从排气管排出,剩下的三分之一热 能由冷却系统来处理。这就意味着只有当热能被均衡地控制,保持发动机温度平衡,发动机才能有 效地工作。 因此,温度对于发动机产生动力来说是至关重要的。如果没有合适的工作温度,发动机就不能 正常工作。如果发动机过热,过高的燃烧室温度会过早点燃混合气,机油黏度会下降,热机油也会 形成机油氧化膜,燃烧室会形成积碳,增加HC排放。过热还会造成发动机性能下降、早期磨损, 甚至导致发动机损坏。再者,金属材料在过高温度和正常温度下的性能是截然不同的。如果发动机 温度过低,燃油汽化不好。若液态燃油进入汽缸,燃油将冲刷缸壁的机油、稀释机油而降低润滑效 果。这也将导致发动机性能下降、HC排放增加、发动机早期磨损。基于这些原因,内燃机必须有 某种形式的冷却系统。 通常有两种形式的冷却系统:水冷系统和风冷系统(汽车发动机)普遍采用水冷系统。其中的冷却 介质或冷却液为水或某些低凝点液体,被称为防冻液。水冷系统由发动机水套、节温器、水泵、散 热器(水箱)、散热器盖、风扇、风扇驱动皮带和必要的软管组成。 水冷系统是指以水作为冷却剂在发动机内循环吸收热量,然后到水箱散热。发动机的冷却主要 通过热量的交换和消耗。混合气燃烧产生的热量必须从铸铁或铝制汽缸传递到水套中的水。水套外 侧将部分热量发散到周围的空气中,但大部分热量通过冷却液到达水箱进行散热。当冷却液温度达 到g0C时,节温器完全打开,节温器倾斜边缘关闭小循环,冷却液大循环流动:水泵+冷却水套+节温 器+散热器进水室+散热器心部+散热器出水室+水泵。 水泵的设计各异,但多数采用离心式。水泵由旋转的叶轮组成,少数容积式水泵采用齿轮或柱 塞。许多水泵带有弹性密封件,防止水泵轴周围漏水。一些V型发动机两侧缸体都有水泵。 散热器用于散发由冷却液所吸收的发动机的热量,因此散热器的构造保证水管内可以容纳大量 的水,并且保证尽量大的散热面积。 散热器通常由心部、上储水室和下储水室组成。散热器心部有两种基本类型:管片式(散热片位 于水管周围以增加散热面积)和管带式或蜂窝型。常见的管片式散热器心部优点是焊接点少,因此 强度高。管片式心部由一系列从上储水室延伸至下储水室的平行水管组成。蜂窝型心部由大量的窄 的水道组成,每对细金属带的两端焊接起来就形成了水道;这些水管通过金属散热片隔开以利于散 热。 散热器盖不仅防止冷却液从加水口溅出,也防止冷却液蒸发。 风扇把冷空气吸进散热器心部。风扇通常安装在水泵轴的延伸处,曲轴前端的一皮带轮通过v

形皮带驱动风扇。这根皮带一般也驱动交流发电机工作,皮带的张紧度通过在支座上摆动发电机的 位置来进行调整。 风冷系统包括离心式风扇、节温器、风扇驱动皮带、散热片、导流板、空气控制罩等。风冷系 统使用空气作为冷却剂,空气在发动机内循环流动,带走运动部件的热量。当发动机工作时,空气 流经散热片进行散热。为了通过控制冷却空气的体积来调节发动机的温度,围绕在发动机周围的金 属壳体内装有节温器。 节温器与空气控制罩相连。发动机温度升高时,空气控制罩开度增加,以进入更多空气;发动机 冷却后,空气控制罩关闭,空气的循环便停止,这样冷机能够迅速走热。由于风冷发动机没有水套 和散热器,因此迅速热机是其特点之一。 发动机冷却系统实质是温度调节系统。新型发动机的冷却系统使发动机保持在足以获得高效燃 烧的高温下工作,但又不致损坏发动机。冷却系统的两项工作就是带走过度热量和维持发动机一定 的工作温度。这些要求对于保证精确空燃比、追求好的燃油经济性和良好排放的电控发动机而言是 非常关键的。

Engine Lubrication System An automobile could not move itself without the aid of friction. However, excessive friction in the engine would mean rapid destruction. Of course, we cannot eliminate friction, but we can reduce it to a considerable degree by the use of lubrication oil so that the automobile can move smoothly with proper friction. The engine lubrication is mainly conducted by the lubrication oil, which has several functions in the lubricating system : first of all, the oil forms a protective coating on the metal surface and prevents a metal to metal contact, thus reducing friction and minimizing wear. Secondly, as the oil is fed to the various moving parts of the engine, it absorbs and carries the heat away from the engine parts. Thirdly as the oil circulates through the moving parts of the engine, it tends to wash off dirt away from the engine parts. Finally, the oil absorbs shocks between bearings and other engine parts, and forms a good seal between piston ring and cylinder walls. Engine lubricating systems are divided into two types: splash, pressure feed. In the splash lubricating system, there are dippers on the lower parts of the connecting rod bearing caps; these dippers enter oil trays in the oil pan with each crankshaft revolution. The dippers splash oil to the upper parts of the engine. The oil is thrown up as the oil sprays, which provides adequate lubrication to valve mechanisms, cylinder walls, piston rings and bearings.

The splash system of lubrication is a simple method and only works successfully if the oil in the sump is maintained at the correct level, neither too high nor too low, and the engine is kept horizontal. Pressure or forced lubrication is used in practically all engines apart from simple lubrication and splash lubrication, and is characterized by the oil being fed under pressure from a pump to the majority of engine parts, especially to main bearings and connecting rod bearings. In modern engine designs, these two methods are often combined. Pressure is developed by the oil pump, which delivers oil to the filter for cleaning before it is sent to the camshaft and valve train components at the top of the engine. Other components are lubricated by splashing oil and by a network of passages, or galleries. The lubricating system, no matter what type, has the job if supplying adequate amounts of oil to all moving engine parts so that the oil can do the various jobs. In some heavy-duty engines, where the oil has a harder and hotter job to do, oil cooler is included in the lubricating system. The oil cooler has a radiator much like the cooling system radiator, through which the oil passes; this cools the oil. All engines have some sort of level indicator, which usually consists of a dipstick, or oil lever stick, that enters the crankcase from the side of the block. To check the oil lever in the open pan, the dipstick can be pulled out and the height of the oil on the stick noted. Oil can then be added if the oil lever is too low for adequate engine protection. In general, the lubrication system of an automotive engine apart from the lubricating passages also contains a reservoir (called the oil pan, sump, or crankcase) to hold the oil supply, a pump to develop pressure, and the valves for controlling flow and pressure etc. The oil pumps are of the positive displacement type in several designs. Vanes, plungers, rotors and gears are all used to build up the necessary pressure. The pumps of gear and rotor types are always positively driven, usually from the camshaft either by means of gears or cams. The oil pump in tractor engine is driven from a gear on the nose of the crankshaft; while in automobile engines, it is driven from a gear made integral with the camshaft. To remove mechanical impurities from the oil circulating through the engine lubrication system, the oil filter is used. The oil filter can filter dirt and solids out of the oil in lubrication system. As these particles of foreign matter are prevented from entering the engine by oil filter, the rate of wear of engine parts is reduced. Engines of more recent designs use a full-flow centrifugal oil filter. That is, all oil passes through the filter before it reaches the bearings. This is a reaction-type centrifugal filter with which all oil delivered by the oil pump is cleaned in the filter rotor. This filter has an oil outlet pipe fitted inside the hollow spindle of the filter rotor and connected to the oil line that distributes the oil to the various parts of the lubrication system. In centrifugal oil filters the rotor consists of a body and a bowl. The surface area of the rotor top is greater than that of the bottom, because the diameter of the upper journal of the spindle is greater than that of the lower journal. The total oil pressure force acting on the top from below is greater than the force acting on the bottom. Therefore, when the engine is running; the rotor is lifted and its bearing end face is thus relived. The higher the pressure in the rotor, the greater the

distance the rotor is lifted through. The thrust washer keeps the maximum lift of the rotor within 0.3 to 1.5 mm. However, in the event the filter gets clogged or obstructed, a bypass valve is provided so that oil will continue to reach the bearings. The oil pressure relief valve is mainly to act both as a pressure regulator and as a safety device in lubrication system. As a pressure regulator, the valve prevents the oil pump from building up excessive pressure. When the oil passages of the rise too high, the relief valve will drain the excess filtered oil into the engine crankcase. As a safety device, the valve is set by the adjusting screw to secure the oil circulation through engine parts under proper pressure.
发动机润滑系统 如果不借助于摩擦,汽车就不能自动行驶,然而过度的摩擦就意味着迅速损毁。当然,我们不 可能消除摩擦,但可以使用润滑油来大幅度减少摩擦,从而使汽车能够利用适当的摩擦平稳行驶。 发动机的润滑主要是通过润滑油的流动实现的,在润滑系统中润滑油的作用是:首先,在金属 表面形成保护油膜以防止金属与金属直接接触,从而减少摩擦、降低磨损;其次,当润滑油到达发动 机各运动零部件时,吸收并带走零部件的热量;第三,润滑油经过发动机运动部件循环流动,会冲刷 机件表面的污物;最后,发动机内轴承和其他机件间的润滑油还吸收运动产生的冲击, 而缸壁和活塞 环之间的润滑油则加强了密封。 发动机润滑系统分为两种形式:飞溅和压力润滑。在飞溅润滑系统中,连杆盖下部有一油勺, 曲轴每转-圈;油勺插入浅盘式油底壳一次。油勺运动将机油甩向发动机上方的部件,这样给配气机 构、汽缸壁、活塞环和轴承提供足够的润滑。 飞溅润滑是一种简单的润滑万式,只有当油底壳的机油平面保持一定高度,不能过高或过低, 且发动机保持水平时才能保证润滑。 除了简单润滑和飞溅润滑外,发动机大都采用压力润滑,压力润滑的特点是机油在机油泵的 压力作用下被送到发动机主要部件,特别是主轴承和连杆轴承。 现代发动机通常结合飞溅和压力润滑两种方式。 机油泵产生压力, 把机油送到滤清器实现清洁, 然后被送到发动机上部的凸轮轴和气门组件。其他零部件通过飞溅和油路网实现润滑。 无论何种类型的润滑系统,都要向所有运动零部件提供足够的机油,而机油具有各种作用。在 大负荷发动机中,机油工作 (条件)更苛刻,温度更高,因此润滑系统中包括机油散热器。机油散热 器的结构与冷却系的散热器相似,流经机油散热器后机油得到了冷却。所有发动机都有某种类型的 指示机油液面的装置,通常为从缸体侧面伸进曲轴箱的机油标尺。检查机油液面高度时,取出机油 标尺,(从机油标尺上)可以看到油液面高度。若液面过低,必须添加机油,以保证发动机的润滑。· 总之,汽车发动机润滑系除油道外,还包括储存机油的油底壳、产生压力的机油泵和控制油路 和油压的阀类等。 容积式机油泵一般有几种不同的类型,采用叶轮、柱塞、转子或齿轮来建立所需要的压 力。齿轮泵和转子泵要通过齿轮或凸轮,由凸轮轴强制驱动。 拖拉机的发动机机油泵由曲轴前端的齿轮驱动,而在汽车上,机油泵由与凸轮轴一体的齿轮带 动。 采用机油滤清器来过滤掉机油中的机械杂质。机油滤清器可以去除机油中的污物及固体颗粒。 这样机油滤清器就阻止了有害杂质进入发动机,发动机零部件的磨损率就下降了。新型发动机大多 采用全流式离心滤清器。也就是说,在进入发动机轴承前机油先要经过滤清器。在反力式离心滤清 器中,机油泵压送的所有机油在转子中被滤清。滤清器的出油口在空心转子轴内并与油路相通,从 而把机油分配到不同的零部件。 离心式滤清器的转子由转子体和转子碗形容器组成。因为转子轴的轴颈上面要比下面大,所以 转子盖的上表面比下表面大,作用于上万的机油压力大于下方。"因此发动机工作时,转子被提升, 转子轴承端面的压力减小。转子内压力越高,转子被提升所经过的距离越长。 止推垫圈保证转子移动的距离在0.3~1.5mm。当滤清器堵塞时,旁通阀会起作用,使机油仍然 到达轴承。 卸压阀就是既作为机油压力调节器又作为润滑系统的安全装置。作为机油压力调节器,它防止 机油泵产生过大的压力。当油路中机油压力过大时,卸压阀打开,多余的经过滤清的机油流回曲轴 箱。作为安全装置,可以通过调整螺钉来设定卸压阀,从而保证润滑系统在一定压力下正常工作。

Engine Ignition System All gasoline engines require some form of ignition system. The purpose of this system is to supply to the spark plugs, within the engine combustion chambers, high-voltage surges. Furthermore, the ignition system must provide these surges or sparks to the correct cylinder of the engine at the proper time in its operating cycle for most efficient combustion. The result of these sparks, of

course, is ignition of the air-fuel mixture within each of the combustion chambers. Modern ignition systems operate from a battery. Conventional systems consist of the battery, ignition coil, distributor, condenser, ignition switch, spark plugs, resistor and necessary low and high tension wiring . The battery is the heat of the total electrical system. In regard to the primary circuit, its function is to supply voltage and current flow to the primary windings of the ignition coil, in order to produce an electromagnet. The primary side of the ignition coil connects in series between the resistor and the breaker points. The function of this coil when current passes through it is to create a very strong

electromagnetic field. In other words, the coil becomes an electromagnet with N and S poles .The magnetic field from this coil, in turn, induces a voltage in the secondary windings that is necessary to cause an arc at the spark plug gap. The secondary ignition circuit not only transforms the 6 or 12 volts of the battery to a voltage high enough to cause an arc at the spark plug but also delivers this high-voltage surge to the spark plugs. The automotive battery supplies either 6 or 12 volts to the primary coil windings. But the voltage necessary to jump across the spark plug air gap and ignite the air-fuel mixture can range from 5 000 to 25 000 volts or more, depending upon the engine's operating condition at any given time. The ignition distributor has several functions. It opens and closes the primary ignition circuit. It distributes the high tension current to the respective cylinders of the engine. It also has a mechanism that controls the point at which the breaker points open, thereby advancing or retarding the spark in accordance with engine requirements. The distributor cap and rotor receive the high-voltage surge from the secondary coil windings through a high-tension wire. This surge enters the distributor cap through its center terminal, known as the coil tower to spark plug electrodes formed into the rim of the cap. The rotor itself mounts on the upper distributor shaft and rotates with it. As a result, the rotor electrode moves from one cap spark plug electrode to another, following the specific firing order of the engine. The purpose of the ignition condenser is to reduce arcing at the breaker points, and prolong their life. Most automotive condensers are formed from two thin foil strips, separated by several layers of insulation. The insulating material is known as a dielectric and is usually paper or any similar nonconductive material. The spark plug provides the gap in the combustion chamber across which the high-tension electrical spark jumps to ignite the combustion charge. The purpose of the ignition switch is to connect and disconnect the ignition system from the battery, so the engine can be started and stopped as desired. With the ignition switch ON, and ignition distributor contacts closed; current will flow from the battery, through the primary winding of the ignition coil, to the distributor contact (breaker) points, to the ground connection and back to the battery. The current flowing through the primary winding of the ignition coil produces a magnetic field in the coil, When the distributor contact points open (break), the magnetic field collapse and the movement of the magnetic field induces current in the secondary winding. Since there are many more turns of wire in the secondary winding than there are in the primary winding, the voltage is increased up to 20 000V. The distributor then directs this high voltage to the proper spark plug, where it jumps to the gap. The heat of the spark ignites the air-fuel mixture in the combustion chamber. The burning fuel expands and forces the piston down. Downward motion of the piston, in turn, rotates the crankshaft. The ignition coil is a pulse transformer designed to step up primary voltage (received from

battery and generator) of 12V to approximately 20 000V. It is composed of a primary winding, secondary winding and core of soft iron. The primary winding is made up of approximately 200 turns of relatively heavy wire. The secondary winding may have as many as 22 000 turns of fine wire. The usual construction is to have the secondary winding wound around the soft iron core, and the primary winding surrounds the secondary. The purpose of the core is to concentrate the magnetic field. This coil assembly usually is placed in a steel case with a cap of molded insulating materials that carries the terminals. Some ignition coils have their windings immersed in oil or paraffin-like material. This is done to improve insulation and reduce the effects of moisture. In addition, oil-filled coils can better withstand corona (faint glow) and heat. Oil has the advantage of automatically healing itself if any breakdown in insulation occurs.
发动机点火系统 所有汽油机都需要某种形式的点火系统。点火系统的功用是向燃烧室内的火花塞提供高压电。 此外,为获得最有效的燃烧,点火系统必须在发动机工作循环的适当时刻向特定的缸提供电火花, 然后点燃各缸内的混合气。 现代点火系统利用蓄电池工作。传统的点火系统由蓄电池、点火线圈、分电器、电容器、点火 开关、火花塞、电阻和必要的高低压导线组成 (如图8·1所示)。 蓄电池是整车电气系统的心脏。对于初级回路而言,它的作用是向点火线圈的初级绕组提供电 压和电流,从而形成电磁体。 点火线圈的初级绕组串联在电阻和断电器触点之间。当电流流经初级绕组时产生强电磁场,也 就是说,点火线圈成为一个带有N极和S极的电磁体,磁场(的变化)会在次级绕组感应出高压电击穿 火花塞间隙放电。 次级点火电路不仅将蓄电池的6V或l2V电压转换成为足以在火花塞上形成跳火的高压,而且还 将此高压脉冲传给火花塞。车用蓄电池向初级绕组提供的是6V或l2V电压。但击穿火花塞间隙所需 要的电压在250OV?田0V甚至更高的范围内变化,其大小取决于发动机当时的工况。 分电器有多个功能,控制初级回路的通断,把高压电分配给相应的各缸,它还有一个控制断电 器触点断开的装置,从而根据发动机的要求提前或延迟发出火花。 分电器盖和分火头通过高压线接受来自次级绕组的高压电。 高压电通过称为线圈架的中心电极 进入分电器盖,再到达形成于分电器盖边缘的火花塞电极。 分火头安装于分电器轴的上端并与其一起旋转。这样,分火头电极按照发动机特定的工作顺序 从一个转至另一个火花塞电极。 电容器的作用是减少断电器触点间的放电,延长触点寿命。大多数车用电容器是很薄的金属箔 片用绝缘材料层相隔制成的。绝缘材料也就是不导电的,通常为纸或类似的材料。 火花塞提供了被高压电击穿的位于燃烧室内的间隙,从而点燃混合气。 点火开关的作用是连接和断开点火系统与蓄电池, 这样发动机才能根据要求起动或停止工作。 如果点火开关闭合而且点火分电器的断电器触点也闭合,则电流就从蓄电池经过点火线圈初 级绕组,到断电器触点,再到搭铁,·回到蓄电池。 流经初级绕组的电流在线圈内产生磁场,当断电器触点打开时,磁场衰减,而磁场的变化在 次级绕组产生感应电流。由于次级绕组线圈的匝数远远大于初级绕组,因此感应电压高达20 000V。 分电器把高压电传递至特定的火花塞, 高压电击穿(火花塞)间隙。 电火花的热量点燃燃烧室内 的空燃混合气。燃料燃烧膨胀推动活塞向下运动,从而使曲轴旋转。 点火线圈是一个脉冲变压器,利用 (蓄电池或发电机的)l2V电压建立大约20 000V的高压。它 由初级绕组、次级绕组和铁心组成。初级绕组由大约200匝粗导线组成,次级绕组则有多达22000 匝的细导线。点火线圈的常见结构是铁心上绕着次级绕组,初级绕组绕在次级绕组外。铁心起着产 生聚集电磁场的作用。 点火线圈总成安装于钢制壳体内,绝缘材料压模制成的盖子上带有电极。有些点火线圈的绕 组浸在油或像石蜡之类的材料中,目的是增加绝缘性,减少湿气的影响。此外,浸油的线圈更能经 受电晕,也更耐热。绝缘材料如果发生击穿,油具有可以自动复原的有利条件。

Engine Starting System Ease of starting is one the major performance characteristics of internal combustion. To start such an engine, it is necessary to spin the engine crankshaft with sufficient speed for good mixing of air and fuel and adequate compression and ignition of the combustible charge. The minimum speed with which the crankshaft of an engine should be rotated to ensure reliable starting of the engine is referred to as the cranking speed. It depends on the engine type and starting conditions. The starting speed is 40 to 50 rpm for carburettor engines and 150 to 250 rpm for diesel engines. Cranking the engine with a lower speed makes it more difficult for the engine to start, for in this case the charge has more time to escape through leaky joints and give off its heat of compression

to the engine components, as a result of which both the pressure and temperature of the charge at the end of the compression stroke are reduced. The starting system provides the power to turn the internal combustion engine over until it can operate under its own power. To perform this task, the starting motor receives electrical power from the battery, and it converts this energy into mechanical energy, which transmits through the drive mechanism to the engine's flywheel. The starting system is convenient to operate and considerably eases the driver's work, but requires skilled maintenance and has only a small store of energy, which limits the number of possible starting attempts. Many engines using an electric starting system are also provided with means for hand starting in case the storage battery or the starter motor should fail. The starting system is a type of electrical circuit that converts electrical energy into mechanical energy. The electrical energy contained in the battery is used to crank a starter motor. As the motor turns, the engine is turned for starting. The system includes the starter motor, a drive and clutch mechanism, and a solenoid that is used to switch on the heavy current in the circuit. A considerable amount of mechanical power is necessary to crank and start a car engine. About 250 to 500 amps of electricity is normally needed. The amperage is higher on a diesel engine. Because of the high amounts of current, heavy cable must be used to energize the heavy-current circuits. The typical starting system has five components: battery, starting switch, battery cables, starting solenoid or switch and starting motor. All starting motors are much the same in general design and operation, differing mainly in the type of drive mechanism used. Basically, the starting motor consists of a housing, fields windings, armature and brushes, end frames, and drive mechanism. The starter housing, or frame, is a heavy cylindrical machined case that serves several functions. This assembly encloses and protects the internal starter components from damage due to the entrance of moisture or other foreign materials. In addition, the housing supports the field coils and forms a conducting path for the magnetism produced by current passing through the coils. Iron is a much better conductor of magnetic line than air.

The connecting way of the field coils selected is determined by the application, engine speed, torque requirements, cable size, battery capacity, and current-carrying capacity of the brushes. Two common connections are the series and series-parallel. The armature in a starter is a rotational part that has many loops of wire with a commutator battery and provides the running surface for the brushes. Brushes are used to make electrical contact between the rotating armature and the stationary battery. They are made from a high percentage of copper and carbon. The purpose of the drive is to engage and disengage the pinion gear from the flywheel. The pinion gear is a small gear located on the armature shaft. When the starter is cranked the pinion gear slides on the shaft and engages the flywheel. The solenoid is an electromechanical device that switches electrical circuits on and off. It is used to start and stop the heavy current that flows to the starter motor during cranking. On many vehicles, there is a linkage attached to opposite end of the armature on the solenoid. The linkage engages the pinion with the flywheel gear. A large, heavy cable of wire is connected from the battery to the starter solenoid. The ignition switch is also connected to the positive side of the battery. A neutral safety switch is included in the circuit. It remains open except when the transmission is in park or neutral. When the transmission is in park, the switch is closed. Current causes the solenoid to engage the starter, and the engine starts.
发动机起动系统 易于起动是内燃机的主要性能特征之一。 要起动发动机, 必须以足够的转速使发动机曲轴旋转, 才能使空气和燃料充分混合, 获得足够的压缩并点燃可燃混合气。 能够确保发动机可靠起动的曲轴 最小转速就称为起动转速,大小取决于发动机类型和起动条件。 化油器式发动机的起动转速为叨?0砖/分钟,柴油机的起动转速为150?50砖/分钟。低速转动的 发动机使发动更难,因为在这种情况下,可燃混合气有更多时间通过接合处漏出,并将压缩热传给 发动机部件,其结果是,在压缩行程终了时可燃混合气的压力和温度都已下降。 起动系统给内燃机提供运转的动力直至其可以靠自身力量运转。 为了完成这一工作, 起动机接 受来自蓄电池的电能并把它转化为机械能,再通过传动装置传递给飞轮。 起动系统操纵方便, 很大程度减轻了驾驶员的工作, 但起动系统需要具有一定技能的维护并且 由于所储存的电能很少,限制了起动次数。许多采用电起动系统的发动机也装有手起动装置,以防 止蓄电池或起动机发生故障。 起动系统利用电路将电能转化为机械能。 蓄电池中的电能被用来使起动机转动, 从而起动发动 机。起动系统包括起动机、传动和离合装置以及用于接通大电流回路的电磁线圈。 要起动小汽车的发动机需要相当大的机械能,一般来说起动电流在250~500A,所以必须使用 较粗的电缆。典型的起动系统有五个零部件:蓄电池、起动开关、蓄电池电缆、起动电磁线圈或开 关和起动机。 所有起动机的设计和工作大致相同, 主要的区别是所使用的传动装置类型。 起动机一般由壳体、 励磁绕组、电枢和电刷、端盖和传动装置组成。起动机壳体为很重的圆柱形外壳,具有多个功能。 壳体将其内部的零部件包起来,保护它们以防止湿气和异物进入 (起动机内部)。另外,起动机壳 体支撑励磁绕组, 为电流流经线圈而形成的磁力提供通道。 对于磁场而言, 铸铁的传导性优于空气。 励磁绕组的连接方式取决于(发动机的)具体应用、转速、所需扭矩、电缆尺寸、蓄电池容量和 电刷的载流容量。通常有串联和混联(串并联)两种连接方式。 起动机中的电枢是一旋转件,电枢上有许多绕组并带有整流器,电枢提供了电刷的运动 表面。 电刷用来接通电枢和蓄电池 (之间的电路)。电刷由高含量铜和碳制成。 传动装置的作用是让驱动小齿轮和飞轮啮合与脱离。 驱动小齿轮安装于电枢轴。 当起动机转动 时,驱动小齿轮在电枢轴上滑动并与飞轮啮合。 电磁线圈是一电动机械装置, 用来接通或关闭电路。 在起动时它可以让大电流流向起动机或停 止时向起动机供电。在许多车辆上,电磁线圈中电枢端的后端有连接装置,使驱动小齿轮与飞轮啮 合。 从蓄电池至电磁线圈采用大载流量的导线连接。点火开关连接到蓄电池正极。 起动系统回路中还有空挡安全开关。除非变速器处于驻车挡或空挡,否则空挡安全开关打开。 当变速器处于驻车挡时,空挡安全开关闭合,电流使电磁线圈与起动机接合,发动机才能起动。

Exhaust System The system that carries exhaust gases from the combustion chamber to the rear of the car is called the exhaust system. The exhaust system collects the high-temperature gases from each

combustion chamber and sends them through an exhaust manifold, heat riser, pipes and mufflers to the rear of the vehicle to be dispersed. A catalytic converter is also adopted in the exhaust system.
排气系统 排气系统把来自燃烧室的废气传至汽车后部。排气系统利用排气歧管、进气预热装置、排气管 和消声器收集各缸燃烧后的高温废气并送到车辆后方排出。排气净化系统通常采用催化转化装置。

The exhaust system has one or two exhaust manifolds, and an exhaust pipe, intermediate pipe, muffler, and tail pipe. The exhaust manifold collects exhaust from the engine's cylinders. The exhaust pipe, intermediate pipe, and tail pipe carry exhaust to the back end of the car. The muffler quiets engine noise.
排气系统有一至两根排气歧管、-根排气管、中间排气管、排气消声器和排气尾管·。排气歧 管收集发动机汽缸的燃烧废气,排气管、中间排气管和排气尾管把废气送到汽车后端。排气消声器 减轻发动机排气噪声。

The burned gases removed from the combustion chamber contain such harmful emissions as hydrocarbons, carbon monoxide oxides, and nitrous. The exhaust system may also reduce these gases.
从燃烧室排出的废气含有碳氢化合物、 一氧化碳和氮化合物等有害气体。 排气系统可以减少这 些有害气体的排放。

Exhaust Manifold The exhaust manifold is connected to the cylinder head of the engine. The exhaust gases from the exhaust valve pass directly into the exhaust manifold. The exhaust manifold is made of cast iron or steel piping that can withstand rapid increases in temperature and expansion. Under full-load conditions the exhaust manifold may be red hot.
排气歧管 排气歧管安装在发动机汽缸盖上。 燃烧废气从排气门直接进入排气歧管。 排气歧管由铸铁或钢 管制成,能够耐高温和热膨胀。在发动机全负荷工作时,排气歧管会烧成红热状。

Several types of exhaust manifolds are used. Four-cylinder engines use either three-or four-runner manifolds. Four-runner ones have a runner for each cylinder, and provide better volumetric efficiency. On six-cylinder engines, the exhaust manifold is either four or six runners. On V-6 and V-8 engines, there is an exhaust manifold on each side.
一般可采用几种形式的排气歧管, 四缸发动机使用三支管或四支管排气歧管。 四支管排气歧管 对于每缸均有一支管相连,可以获得更好的容积效率。六缸发动机采用四支管或六支管排气歧管, 在V6和V8发动机中,每侧缸体均有一根排气歧管相连。

Heat Riser Most engines have a type of heat riser attached to the exhaust manifold. The heat riser is a valve to restrict the exhaust gases during starting and warm-up periods. This restriction tends to raise the engine to operating temperature more quickly, which aids in the vaporization of fuel. On in-line engines, the heat riser also helps to vaporize the fuel during cold starting.
进气预热装置 大多数发动机都有进气预热装置与排气歧管相连。 进气预热装置阀用以在冷起动热机时限制废 气。预热装置阀的作用可以使发动机更迅速升温,从而有助于燃油蒸发。在直列式发动机中,预热 装置也有助于冷起动时燃油的蒸发。

The heat riser is controlled by a flat spring. When the engine is cold, the spring and a counterweight cause a valve in the exhaust manifold to close. As the spring heats up, it relaxes and causes the counterweight to open the valve and allow normal exhaust.
预热装置阀由簧片控制。发动机冷机时,簧片与配重使预热装置阀关闭。温度升高时,簧片松 弛,使配重打开预热阀,恢复正常排气。

Exhaust Pipe The exhaust pipe is the connecting pipe between the exhaust manifold and the muffler or catalytic converter. Many types of exhaust piping are used on vehicles. The shape depends on the configuration and size of the engine, and undercarriage of he car. It can also be single or dual design.
排气管

排气管安装在排气歧管和消声器或催化转化装置之间。 汽车上所使用的排气管类型很多。 排气 管的外形取决于发动机的布置和尺寸以及汽车底盘的构造,可以设计为单排气管或双排气管。

Exhaust Muffler The muffler lessens the noise caused by combustion. This round, or oval-shaped, canister fits between the intermediate pipe and the tail pipe. Inside the muffler, there are tubes, baffles, and chambers that absorb noise.
排气消声器 排气消声器减轻了燃烧产生的噪声。排气消声器为圆形或椭圆形管,位于中间排气管和排气 尾管之间。排气消声器有管、隔板和消音腔。

Exhaust gases enter the inlet pipe and go to the opposite end of the muffler, turn around and flow through another pipe back to the inlet end. Then the gases turn again and exit through an outlet pipe. As these gases travel through the muffler, the baffles and chambers absorb sound.
废气首先进入消声器的进气管,然后到达出气端,再经过另一根管回到进气端。这样排气在 消声器内循环流动,最后从出气管排出,同时隔板和消音室吸收了噪声。

The tail pipe fastens to the outlet end of the muffler. In many cars, a U-bolt pipe clamp holds the tail pipe to the muffler outlet. A tail pipe carries exhaust gases to the back of the car.
排气尾管固定于排气消声器的排气端。在大多数小汽车中,采用U型螺栓紧固排气尾管和消 声器排气端。排气尾管把废气带到汽车后方。

Resonator A resonator is another type of muffler. Most of the noise from an exhaust system is sound vibration. These vibrations cause louder noise. Resonator provides additional sound protection at critical points in the exhaust flow. They are used to absorb excessive sound vibration.
辅助消声器 辅助消声器是另一种形式的排气消声器。排气系统的多数噪声属于振动噪声,振动产生的噪 声更大。 辅助消声器在排气流动的关键处提供了额外的降低噪声保护, 它们用于吸收过多的振动噪 声。

Tail Pipe The tail pipe is a tube that is adopted to carry the exhaust gases from the muffler or resonator to the rear of the automobile. The shapes and sizes depend on the vehicle.
排气尾管 排气尾管的作用是把来自消声器或辅助消声器的废气传送至汽车后方,它的外形和尺寸决定 于车辆类型。

The clutch Every vehicle has an engine which provides the starting power, but the engine develops little power or torque at low rpm, and must gain speed before it moves a vehicle. However, if the rapidly rotating engine was suddenly connected to the driveline of a stationary vehicle, the engagement would not be soft but violent. So, to reach the soft engagement, the clutch is needed. The clutch is a device used to provide smooth engagement and disengagement of engine and transmission. In other words, the clutch assists in starting a vehicle by conducting the engine power smoothly to the transmission. The engagement of engine and transmission means the linkup between engine and drivetrain to transfer the engine power to the driving axles and wheels, and their disengagement means the halt to power transfer that allows the engine to operate while the transmission does not. Most cars equipped with a manual transmission use a single plate, dry clutch disc, a diaphragm type pressure plate and cover assembly, a clutch release bearing, and a clutch release fork. The clutch has a clutch disc as its major part, and the clutch disc consists of a circular metal plate attached to a reinforced splined hub. Often the hub is mounted on coil springs to provide cushioned engagements. The splined hub is free to slide lengthwise along the splines of the transmission input shaft. When engaged, the clutch disc drives the input shaft through these splines. The clutch disc operates in conjunction with a pressure plate or clutch cover. In its operating position in the engine /transmission linkup, the clutch disc is sandwiched between the engine flywheel and clutch pressure plate. The clutch fork and linkage provide the means of converting the up-and-down movement of the clutch pedal to the back-and-forth movement of the clutch release bearing assembly. The clutch

release bearing, in most cases, is a ball bearing assembly with a machined face on one side that is designed to contact the pressure plate diaphragm release fingers during disengagement. Engagement and disengagement of the clutch assembly are controlled by a foot pedal and linkage (rod or cable) that must be properly adjusted and relatively easy to apply. The machined surfaces of flywheel and pressure plate(against which the clutch facings bear) must be flat, true, and free from cracks or score marks. The transmission, pressure plate, flywheel housing, clutch disc, flywheel, and crankshaft must be properly aligned to prevent slippage, vibration, and noise. All automotive clutches used with standard transmissions are very similar in construction and operation. There are some differences in the details of the linkages as well as in the pressure-plate assemblies. In addition, some clutches for heavy-duty applications have two friction disks and an intermediate pressure plate. Also, some clutches are operated by hydraulic means. Three types of

clutch are the coil-pressure-spring type, diaphragm-spring type, and semi-centrifugal type. Cars equipped with automatic transmissions normally do not have a clutch. On these, the transmission operates automatically so that the driver is not required to use a clutch to shift gears.
离合器 每辆汽车都有一个提供动力的发动机,但是发动机在低速转动时几乎不产生动力或扭矩,而且 发动机必须快速转动才能推动车辆前进。然而,如果快速转动的发动机突然与静止车辆的驱动系统 相连接,这种接合就不会柔和,相反会相当猛烈。因此,要达到柔和接合,就必须要有离合器。 离合器是一种用以连接和分离发动机和变速器的装置。换句话说,离合器将发动机动力柔和地 传给变速器,以此来帮助车辆起步。发动机和变速器的连接就是发动机和传动系统的连接,并以此 将发动机动力输送至驱动桥和车轮,而发动机和变速器的分离就是停止这种动力传递,但发动机仍 允许继续运转而变速器则不行。大多数装各有手动换挡变速器的车辆采用单片干式离合器盘、膜片 式压盘和外壳总成、离合器分离轴承以及离合器分离叉。 离合器(如图11· 1所示)以离合器从动盘为其主要部件, 而离合器从动盘有丁个装于加强花键轮 毅上的圆形金属板。螺旋弹簧通常安装在轮毅的弹簧座孔内,它能产生弹性结合。花键轮毅在变速 器输入轴的花键上纵向地自由滑动。"当离合器盘被连接时,它就会通过花键联接驱动输入轴。离 合器从动盘连同离合器压盘或离合器外壳一起工作,当离合器处于发动机与变速器接合状态时,离 合器从动盘被夹在发动机飞轮与离合器压盘中间。 离合器叉和连动装置将离合器踏板的上下运动转 变为离合器分离轴承总成的前后运动。在许多情况下,离合器分离轴承是一个球轴承总成,它的一 侧带有机加工面;·在分离状态时,与压盘上的分离杠杆接触。 离合器总成的接合和分离可由调节适当并方便使用的脚踏板以及连动装置 (杆件或电缆)控制。 飞轮与压盘 (通过分离轴承使压盘压紧或放松从动盘)的机加工平面必须平展、 精密, 没有裂缝或刻 痕。变速器、压盘、飞轮壳、离合器从动盘、飞轮以及曲轴必须校正定位好才能防止打滑、抖动和 异响。 所有使用标准传动系统的汽车离合器在构造和操作上都很相似。 只是在压紧机构和连动装置的 细节上稍有不同。此外,一些在重载荷情况下工作的离合器,有两个带摩擦衬片的圆盘和一个中间 压盘。还有一些离合器是液压式的。离合器的三种类型为:螺旋弹簧式、膜片弹簧式和半离心式。 装有自动变速装置的汽车一般不需要离合器。在这些汽车上,变速器自动操作,因此驾驶员不 必使用离合器来换挡。

Transmission A transmission is a speed and power changing device installed at some point between the engine and driving wheels of the vehicle. It provides a means for changing the ratio between engine rpm (revolutions per minute) and driving wheels rpm to best meet each particular driving situation. The transmission is designed for changing the torque transmitted from the engine crankshaft to the propeller shaft, reversing the vehicle movement and disengaging the engine from the drive line for a long time at parking or coasting. A higher torque should be applied to the wheels to set an automobile in motion or move uphill with full load than to keep it rolling after it gets under way on level stretches of the road, when inertial is high and tractive resistance is low. To meet these variable torque requirement, special gear box are used. Such gear boxes are called fixed-ratio transmissions. The transmission with two sliding gears or synchronizer sleeves is called two-range, with three gears, three-range. Depending on the number of forward speeds there are three, four and five-speed transmissions. The gear box casing consists of an aluminium alloy or malleable iron casting extended at the front to form the clutch-housing or, alternatively, having a separate bolted-on housing. The rear of the casing carries the engine mountings, where there are not fixed to the clutch housing or the rear of the crankcase. The engine torque is conveyed from the driven disc of the clutch by the clutch (primary or first motion) shaft. The clutch shaft revolves in a bearing in the gearbox casing and has an integral pinion which is in permanent engagement with a corresponding pinion on the layshaft below it, the two being termed the constant-mesh pinions. The layshaft consists of a cluster of four pinions, including the constant-mesh pinion, rotating together either upon a fixed layshaft spindle or in bearings in the gearbox casing. The splined mainshaft is carried in a spigot bearing in the clutch shaft and in a bearing in the gearbox casing at the rear end, and is coupled to the propeller shaft through a universal joint. Sliding on the mainshaft are two splined pinions having integral collars into which fit the selector forks. The second gear pinion has projection 'dogs' on the side facing the clutch shaft, and when slid along the splined mainshaft by the selector fork, the dogs mate with corresponding projections on the clutch shaft to give a positive 'direct' drive between the two shafts for top gear. For second gear the mainshaft pinion is slid into engagement with the second gear pinion on the

layshaft. The drive is "indirect" and passes from the clutch shaft through the constant-mesh gears to the layshaft and back to the mainshaft through the second gear pinions. In this case the first gear pinion on the mainshaft is engaged with the corresponding first gear pinion on the layshaft and due to their respective sizes a greater gear reduction is obtained than with the secondgear pinions. The ratio is calculated in a similar manner, using the number of teeth on the first gear pinions. The fourth pinion on the layshaft is permanently engaged with a reverse idler pinion turning on a short shaft fixed in the gearbox casing. When the first gear mainshaft pinion is moved into engagement with this idler pinion the direction of rotation of the mainshaft is reversed. In calculating the reverse gear ratio, the number of teeth on the first gear mainshaft pinion and on the layshaft reverse gear pinion are taken, since the size of the idler pinion is immaterial to the gear ratio. Automatic gearbox is commonly used in modern car and construction machinery. It has three basic systems: a torque converter, a gear system, and a hydraulic system. These fit together in a unit that fastens directly behind the engine. The torque converter is like the clutch in a manual gearbox. It is the coupling between the engine and the drive train that transmits power to the drive wheels. The hydraulic system is the "brain" of the gearbox. This section must know when to change from one gear to another. It must also provide the fluid pressure needed to apply or release the parts of gear section so that the gears shift at the correct time. The hydraulic section is a complex maze of passages and vales that senses speed and load. The gear section has gears that change the gear ratios for torque multiplication and gear reduction. Automatic transmissions also has the input and output shaft needed to transmit power to the drive wheels.
变速器 变速器是一个速力变化装置,安装在车辆的发动机和驱动轮之间。变速器用以改变发动机转速 与驱动轮转速间的比率关系,以适应每种行驶状况。 变速器被设计用来改变发动机传递到传动轴的转矩,实现汽车的倒向行驶,在停车和滑行时中 断发动机和传动系之间的动力连接。 在汽车全负荷运行或爬坡时必须有较高的转矩来保持车轮的滚 动,当惯性比较大、行驶阻力比较小时,车辆可以继续滑行一段距离。采用变速器是为了满足这些 变量扭矩需求。这种变速器叫做固定传动比变速箱。带有两个滑动齿轮传动机构或同步器啮合套的 变速器叫做二位变速器,有三个传动齿轮机构叫三位变速器。根据向前的传动此分为三、四和五速 变速器。 变速器壳体是由铝合金或可锻铸铁铸造成的,前面与离合器壳体连接或有独立的壳体。壳体的 后端与发动机的附件连接,不与离合器壳体或曲轴箱的后端连接。 发动机转矩通过变速器第一轴从离合器的从动盘传递。 变速器输入轴在变速器壳体上的轴承中 旋转,输入轴上有齿轮与下面中间轴上的齿轮啮合,这两个齿轮叫做常啮合齿轮。 中间轴由一组四个小齿轮组成, 包括常啮合齿轮, 它们一起在变速器壳体上的轴承支撑上旋转。 带有花键的输出轴 (第二轴)支撑在输入轴 (第一轴)中心的轴承上,后端支撑在变速器壳体的轴承 上,并通过万向节与传动轴连接。输出轴上有两个齿圈,可以通过拨叉选择合适的挡位。 L挡齿轮在正对输入轴的一侧有凸齿/当齿轮沿着花键移动时,齿和输入轴的凸部结合时,这样 在输入轴和输出轴之间就是直接挡位。 在二挡时,输出轴的齿轮与中间轴上的二挡齿轮啮合。这不是直接传动,是从输入轴通过常啮 合齿轮传动到中间轴,再通过二挡齿轮传递到输出轴。 在这种情况下,第二轴的一挡滑动齿轮与中间轴的一挡齿轮啮合,获得比二挡更大的传动比。 传动比用相同的方式计算,使用-挡齿轮的齿数。 中间轴上的第四个齿轮与安装在壳体上短轴上的倒挡齿轮常啮合。 当输出轴上的一挡齿轮与这 个惰轮啮合,输出轴的旋转方向相反。在计算倒挡传动比时,输出轴上的齿数和中间轴的倒挡齿轮 的齿数被使用,惰轮的齿数与传动比无关。 自动变速器在现代汽车和工程机械中广泛运用。它有三个基本的系统:。一个变矩器,一个齿 轮传动机构系统和液压系统,它们制成一体,直接牢固地连接在发动机后面。液力变矩器就像手动 变速器中的离合器。它连接发动机和传动系统,把发动机的动力传递到驱动轮上。 液压系统是变速器的"大脑"。液压系统知道何时从一个挡位变换到另一挡位。它可以提供需要 施加或释放齿轮传动部分的流体压力,以便传动机构在正确时间变挡。"液力部分是一个复杂的迷 宫通道和感应速度及负荷的阀门。 传动机构的齿轮可以根据扭矩增加和速度减少改变传动比。 自动变速器也有输入轴和输出轴把 动力传递到驱动轮上。

Automobile Suspension System

Automobile suspension system has two basic functions, to keep car's wheels in firm contact with the road and to provide comfortable ride form the passengers. A lot of the system's work is done by the spring. Under normal conditions, the springs support the body of the car evenly by compressing and rebounding with every up-and-down movement. This up-and-down movement, however, causes bouncing and swaying after each bump and is very uncomfortable to the passenger. This uncomfortable effects are reduced by the shock absorbers. Suspension, when discussing cars, refers to the use of the front and rear springs to suspend a vehicle's "sprung" weight. The springs used on today's cars and trucks are constructed in a variety of types, shapes, sizes, rates and capacities. Types include leaf springs, coil springs, air springs, and torsion bars. They may be paired off on vehicles in various combinations and are attached to vehicles by several different mounting techniques. The leaf springs most commonly used in automobiles is made up of several long plates, or leaves. The leaf spring acts like a flexible. For example, if you tried to bend a solid beam, the top edge would try to get longer while the bottom edge would try to push together. The result is that the top edge of the beam might pull apart and the beam might break. Because the leaf spring consists of a series of thin leaves, one on top of another, it does not break when bent. When the spring is bent, the individual leaves bend and slip over one another. This provides a spring with great flexibility and strength. In the rear-suspension systems of many cars, coil springs are used instead of leaf springs. The coil spring is made from a length of steel road rod would into a coil. The coil spring is very elastic and will compress when a weight is put on it. The heavier the weight the more spring will compress. A rear-suspension system uses coil springs. Each spring is assembled between spring seats in the car frame or body and lower control arms, or pads, on the axle housing. When the rear wheels hit a hole or a bump in the road, the springs expand or compress to absorb the shock. The coil-spring rear-suspension system has four control arms. Two of the arms are upper control

arms, and two are lower control arms. The purpose of the arms is to keep the rear axle housing in alignment with the frame. The two upper control arms are pivoted on the rear cross member and the differential carrier. The two lower control arms are pivoted on the frame and the axle housing. The lower control arms prevent forward-and backward movement of the housing. These arms permit the rear-axles housing to move up and down. But they prevent sideward or forward-and-backward movement. As in other suspension systems, a shock absorber is used at each wheel. The front-suspension system must allow the wheels to move up and down. It must also allow the wheels to pivot from side to side so that the car can be steered. A front-suspension system uses coil springs. In the system, the coil spring is bolted between spring seat in the car frame and a lower control arm. The inner ends of both the lower and upper control arms are pivoted on the car frame. The outer ends of the control arms are connected to the steering knuckle. The steering knuckle is attached to the control arms through ball joints. These ball joints allow the steering knuckles to swing to the left or right for steering. In the assembled car, the wheels are mounted on the spindles of the steering knuckles. Swinging the knuckles from the left to right pivots the front wheels so that the car can be steered. In the past, a wide variety of direct and indirect shock absorbing devices were used to control spring action of passenger cars. Today, direct, double-acting hydraulic shock absorbers and shock absorber struts have almost universal application. The operation principle of direct, double-acting hydraulic shock absorbers is forcing fluid through restricting openings in the valves. This restricted flow serves to slow down and control rapid movement in the car springs as they react to road irregularities. Usually, fluid flow through the pistons is controlled by spring-loaded valves. Hydraulic shock absorber automatically adapts to severity of the shock. If the axle moves slowly, resistance to the flow of fluid will be light. If the axle movement is rapid or violent, the resistance is stronger, since more time is required to force fluid through openings. By these actions and reactions, the shock absorbers permit a soft ride over small bumps and provide firm control over spring action for cushioning large bumps. The double acting units must be effective in both directions because spring rebound can almost as violent as the original action that compressed the shock absorber.
汽车悬架系统 汽车悬架系统有两个作用:保持汽车车轮与路面的良好接触,提供乘客的乘坐舒适性。大量的 工作是由弹簧来完成的。在正常情况下,弹簧通过压缩和伸张均匀地支撑着车身上下运动。车身的 上下运动在每一次冲击后会引起跳动和摆动,这样会使得乘客很不舒服。这种不舒适性可以通过减 震器来降低。 当我们谈论汽车悬架时,是指前后弹簧用来悬挂的汽车重量。在现代的汽车上弹簧的结构有很 多形式、形状、尺寸、标准及负载。弹簧种类包括钢板弹簧、螺旋弹簧、空气弹簧和扭杆弹簧。弹 簧以各种组合形式在车辆上配套使用,并用不同的装配技术将弹簧安装在车辆上。 汽车中运用最广泛的弹簧是钢板弹簧,它由几片长短不一的钢片构成。钢板弹簧工作时有很好 的弹性。例如,如果你想把杆件弯曲,外侧将变得更长广点,而内侧将受到挤压。这样将会导致变 长的一侧会被拉开,杆件将会被折断。 由于钢板弹簧是由一组薄的钢片组成,一片叠加在另一片上,在弯曲的时候不会折断,每一片 独立的钢片弯曲时,钢片之间会产生相对移动。这样会使得弹簧有很强的韧性和强度。 在许多 车辆的后悬架系统中,螺旋弹簧代替了钢板弹簧i螺旋弹簧是由一段钢丝卷成线圈。螺旋弹簧有较 好的弹性,当有重量施加在弹簧上时,弹簧将被压缩。施加的重量越重,弹簧的压缩量越大。 后悬架系统使用螺旋弹簧。 每一个弹簧安装在车架或车身的弹簧座和后桥壳上的下控制臂或杆 之间。当后车轮在道路中遇到坑或撞击时,弹簧伸张或压缩来吸收震动。 螺旋弹簧后悬架系统有四个控制臂,即两个上控制臂和两个下控制臂。设置控制臂的目的是要 保持车轮的相对位置。上控制臂与后面的横梁和差速器支架铰接在一起。下控制臂与车架和桥壳铰 接。下控制臂避免桥壳的向前和向后运动。控制臂允许后桥壳上下移动,但是避免前后或向旁边运 动。同样在其他的悬架系统中,在每个车轮上都使用了减震器。 前悬架系统允许车轮上下跳动,也允许车轮从一侧转到另一侧,进而实现汽车的转向,前悬架 使用螺旋弹簧。 在系统中,螺旋弹簧用螺栓连接在车架和下控制臂之间的弹簧座上。下控制臂和上控制臂的内 端都铰接在车架上。控制臂的外端连接到转向节上。转向节与控制臂通过球头万向节连接。球头万 向节允许转向节在转向时摆动到左侧和右侧。在汽车总成中,车轮装在转向节的轴上。转向节从左 边转到右边,带动前轮转动,实现汽车转向。 过去,在车辆上各种各样的直接或间接吸收震动装置用于控制弹簧的活动。现在,双向作甩直 接作用液压减震器得到广泛应用。 双向直接作用液压减震器的工作原理是推动液体从阀体的阻尼孔中流过。 当汽车通过不规则的

路面时,液体流动速度减慢控制汽车快速移动。通常,弹簧负荷阀控制液体通过活塞。液压减震器 自动地适应剧烈的震动冲击。 如果车桥缓慢移动, 对液流的阻尼会很小。 如果车桥快速或剧烈运动, 阻力就会变得很强,因为有更多的时间需要推动液体通过阻尼孔。通过这些作用和反作用,减震器 在受到小的冲击时动作柔和,在受到剧烈的冲击时需要较强的弹簧作用控制。双向作用在两个方向 上都是有效的,因为弹簧在从初始位置压缩减震器和弹簧反弹的作用一样剧烈。

Automobile Steering System The manual steering system consists of (1) steering wheel and column, (2) a manual gearbox and pitman arm or a rack and pinion assembly, (3) linkages; steering knuckles and ball joints, (4) the wheel spindle assemblies. In the pitman arm system, the movement inside the steering box causes the pitman shaft and arm to rotate, applying leverage to the relay rod, which passes the movement to the tie rods. Power steering systems add a hydraulic pump; fluid reservoir; hoses; lines; and either a power assist unit mounted on, or integral with, a steering wheel gear assembly. There are several manual steering systems gears in current use. The "rack and pinion" type choice of most manufacturers. The "recirculating ball" type is past favorite because the balls act as a rolling thread between the worm shaft and the ball nut. Another manual steering gear once popular in imported cars is the "worm and sector" type. Other manual gears are "worm and tapered pin steering gear" and "worm and roller steering gear". Steering gears The steering gear converts the rotary motion of the steering wheel into straight-line motion. This moves the linkage to the steering arms on the steering knuckles, swinging the front wheels left to right. There are two basic types of steering gears. One type has a pitman arm attached to a shaft from the steering box. The second type is the rack-and-pinion steering gear. The pitman-arm steering gear has two essential part. They are a worm gear on the end of the steering shaft and a matching sector gear or toothed roller attached to the sector shaft. As the steering shaft and worm gear rotate, the sector gear must follow the worm gear. The sector gear is moved toward one end of the worm or the other, as the ball nut moves up and down on it. The sector-gear movement causes the pitman arm to swing one way or the other. Friction is kept low by using balls between the major moving parts. The balls roll between the worm teeth and the grooves cut in the hole in the ball nut. As the worm turns, the balls roll in worm teeth. The balls must also roll in the grooves inside the ball nut. As the worm rotates, the balls cause the nut to move up or down along the worm. This motion is carried by the teeth on the outside of the ball nut to the teeth on the sector gear. The sector gear must move. This movement rotates the sector shaft which swings the pitman arm. The steering gear is called a worm-and-roller steering gear. The roller move from one end of the worm gear to the other. When the roller reaches the end, they enter roller-return guides, which take them back into the roller nut. The rack-and-pinion steering gear is used mostly on smaller cars. This system has a pinion gear on the end of the lower steering shaft. The pinion is meshed with a rack of gear teeth cut on the underside of the major cross member of the steering linkage. When the steering wheel is turned, the pinion turns. This moves the rack to the left or right. The movement is carried through the rods to the steering arms at the from wheels. Power rack-and-pinion steering assemblies are hydraulic mechanical unit with an integral piston and rack assembly. An integral rotary valve directs power steering fluid flow and controls pressure to reduce steering effort. The rack and pinion is used to steer the car in the event of power steering power failure, or if the engine (which drives the pump) stalls. When the steering wheel is turned, the resistance is created by the weight of the car and tire-to-road friction, causing a torsion bar in rotary valve to defect. This changes the position of the valve spool and sleeve, thereby directing fluid under pressure to the proper end of the power cylinder. The difference in pressure on either side of the piston (which is attached to the rack) helps move the rack to reduce turning effort. The fluid in the other end of the power cylinder is forced to control valve and back to the pump reservoir. When the steering effort stops, control valve is centered by the twisting force of the torsion bar, the pressure is equalized on both sided of the piston, and the front wheels return to a straight ahead position. Power steering In the power-steering system, a pump sends fluid under pressure into the steering gear. This high-pressure fluid does about 80 percent of the work of steering. The steering-gear assembly looks almost like the manual-steering gear, except that the steering-gear box is larger. The pump is driven by a

belt from the crankshaft pulley. In operation, the pump produces a high pressure on the power-steering fluid. This fluid is special oil. Steering linkages These are several types of steering linkages. All have the same job. They carry the movement of the steering wheel from the steering gear to the steering arms at the wheel. It includes an intermediate rod, which is supported at one end by the pitman arm and at the other end by the idler arm. The outer ends of the intermediate rod are attached to the steering-knuckle arms by short tie rods. Notice that the tie rods have adjuster sleeves. The purpose of these sleeves is to adjust tie rods.
转向系统 手动转向系统组成:(1)方向盘和转向柱;(2)转向器和转向垂臂或一个齿条与齿轮总成;(3)杆件、 转向节和球头万向节;(4)车轮轴总成。 转向器内部的运动使得转向垂臂转动,通过直拉杆把运动传递到转向横拉杆。 动力转向增加了一个液压泵、油缸、油管和动力辅助装置,与转向机构制成干体。 目前使用的转向机构有以下几种:齿轮齿条式转向器是大部分生产厂家采用的形式;循环球式是 过去最受欢迎的形式,因为循环球在蜗杆和滚道之间滚动;另一种蜗轮齿扇式曾流行于进口车上;其 他的传动机构是曲柄指销式和蜗轮蜗杆式。 转向器 转向器把万向盘的回转运动转变为直线运动,带动转向节上的转向节臂偏转。转向器有两种基 本形式:一种形式是垂臂与转向器的输出轴连接;另一种是齿轮齿条式转向器。 转向垂臂转向器由两个基本部分组成。 在转向轴的末端有一个蜗轮和与之相匹配的齿扇或齿轮 啮合。 当转向轴和蜗轮转动时,齿扇也随着蜗轮转动。齿扇向蜗杆轴的一端移动,或向另一端移动, 循环球滚道在蜗杆上上下移动。齿扇的运动使得垂臂向-侧摆动。 在两个重要的运动部件之间采用循环球,摩擦是很小的。循环球在蜗杆齿和在循环球壳体上的 孔里铣出的槽之间滚动i当蜗杆转动时,循环球在蜗杆齿之间滚动。循环球只能在循环球壳体内滚 动。 当蜗杆转动时, 循环球可以使得壳体沿着蜗杆上下移动。 这些运动是由循环球外侧的齿传递的, 齿扇也要跟着运动。这个运动会转动齿扇轴来带动垂臂。 转向器又被叫做蜗杆和滚轮转向器。循环球从滚轮的一端移动到另一端。当滚子到达末端,进 入导管,再次把循环球送回循环球壳体。 在大部分微型车上采用齿轮齿条转向器。这个系统在方向盘传动轴末端有一个小齿轮。齿轮和 转向器中支架上齿条的齿啮合。 当万向盘转动时, 齿轮也旋转。 齿条向左右运动。 当方向盘转动时, 小齿轮旋转。运动通过杆件传递到前轮的转向节臂。 齿轮齿条转向器的助力装置是带有活塞的液压机构和齿条总成。整体回转阀直接推动流体,控 制压力,减少转向力。在助力转向失效或发动机熄火 (发动机驱动油泵)时,齿轮齿条可以用来完 成转向。 当方向盘转动时,由于车辆的重量和轮胎与路面摩擦产生摩擦阻力,会引起回转阀中的扭力杆 扭转,产生"路感"。改变阀杆和套筒的位置,液体可以在压力的作用下直接进入动力油缸底部。活 塞两侧的压力不同(活塞安装在支架上),可以减少转向的作用力。助力油缸底部的液体被推动通过 控制阀,流回储油缸。当撤除方向盘上的外力时,控制阀被扭杆拉到中间位置,活塞两侧的压力相 等,前轮回到直线位置。 动力转向 在动力转向系统中,油泵把油液送到转向器中。高压液体大约可以承担转向力的80%。转向器 机构就像普通转向器一样,不过转向器的壳体大一些。凸轮轴上的皮带轮通过皮带驱动油泵。工作 时,油泵使转向助力装置提供高压液压油。液压油为专用油液。 转向杆件 转向杆件有几种类型。 它们的工作是相同的。 它们把方向盘的运动从转向器传递到转向节臂上。 中间杆件一端由转向垂臂支撑另一端由随动转向臂支撑。中间杆的外端通过横拉杆与转向节臂连 接。 横拉杆有定位套筒。 套筒是为了调整拉杆。 当定位套筒转动时, 转向横拉杆能有效变长或变短。 它使前轮轻微地摆动。

Automobile Brake System Two complete independent braking systems are used on the car. They are the service brake and the parking brake. The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by

when a separate parking brake foot pedal or hand lever is set. Basically, all car brakes are friction brakes. When the driver applies the brake, the control device forces brake shoes, or pads, against the rotating brake drum or disks at wheel. Friction between the shoes or pads and the drums or disks then slows or stops the wheel so that the car is braked. In most modern brake systems, there is a fluid-filled cylinder, called master cylinder, which contains two separate sections, there is a piston in each section and both pistons are connected to a brake pedal in the driver's compartment. When the brake is pushed down, brake fluid is sent from the master cylinder to the wheels. At the wheels, the fluid pushes shoes, or pads, against revolving drums or disks. The friction between the stationary shoes, or pads, and the revolving drums or disks slows and stops them. This slows or stops the revolving wheels, which, in turn, slow or stop the car. Drum brakes, it consists of the brake drum, an expander, pull back springs, a stationary back

plate, two shoes with friction linings, and anchor pins. The stationary back plate is secured to the flange of the axle housing or to the steering knuckle. The brake drum is mounted on the wheel hub. There is a clearance between the inner surface of the drum and the shoe lining. To apply brakes, the driver pushes pedal, the expander expands the shoes and presses them to the drum. Friction between the brake drum and the friction brings brakes the wheels and the vehicle stops. To release brakes, the driver release the pedal, the pull back spring retracts the shoes thus permitting free rotation of the wheels. Disk brakes, it has a metal disk instead of a drum. A fiat shoe, or disk-brake pad, is located on each side of the disk. The shoes squeeze the rotating disk to stop the car. Fluid from the master cylinder forces the pistons to move in, toward the disk. This action pushes the friction pads tightly against the disk. The friction between the shoes and the disk slows and stops it. This provides the braking action. Piston are made of either plastic or metal. There are three general types of disk brakes. They are the floating-caliper type, the fixed-caliper type, and the sliding-caliper type. Floating-caliper and sliding-caliper disk brakes use a single piston. Fixed-caliper disk brakes have either two or four pistons. The brake system assemblies are actuated by mechanical, hydraulic or pneumatic devices. The mechanical leverage is used in the parking brakes fitted hi all automobile. When the brake pedal is depressed, the rod pushes the piston of brake master cylinder which presses the fluid. The fluid flows through the pipelines to the power brake unit and then to the wheel cylinder. The fluid pressure expands the cylinder pistons thus pressing the shoes to the drum or disk. If the pedal is released, the piston returns to the initial position, the pull back springs retract the shoes, the fluid is forced back to the master cylinder and braking ceases. The primary purpose of the parking brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by the driver when a separate parking braking hand lever is set The hand brake is normally used when the car has already stopped. A lever is pulled and the rear brakes are applied and locked in the "on" position. The car may now be left without fear of its rolling away. When the driver wants to move the car again, he must press a button before the lever can be released. The hand brake must also be able to stop the car in the event of the foot brake failing. For this reason, it is separate from the foot brake uses cable or rods instead of the hydraulic system.
制动系统 在汽车上使用两套完全独立的制动系统。它们是行车制动和驻车制动。 行车制动是减慢车速、停车或在行驶过程中控制车辆。它们是由驾驶员踩下和松开制动踏板来 实现的。制动的最主要的目的是控制车辆的稳定。驻车制动是机械装置,它设置有独立的驻车制动 踏板或手动杆件。 基本上所有的制动都是摩擦制动。当踩下刹车时,控制机构推动制动蹄片或制动块,阻止制动 鼓转动。制动蹄片或制动块和制动鼓或制动盘之间产生摩擦,降低或停止车轮的转动速度,以便汽 车制动。 现代车辆的制动系统中,有一个充满液体的油缸叫制动主缸,它分为独立的两部分,每部分里 面都有一个活塞,两个活塞都和驾驶室内的制动踏板连接。当制动踏板被踩下时,制动液从主缸被 送到车轮的轮缸上。在车轮的轮缸上,液体推动制动蹄片或制动块阻止制动鼓或制动盘的转动。在 固定的制动蹄片或制动块和转动的制动鼓或制动盘之间产生摩擦力,这样可以降低车速或制动汽 车。减速或制动转动的车轮,可以把汽车的速度降下来,或停止车辆。 鼓式制动,它是由制动鼓、涨鼓器 (制动凸轮)、回位弹簧、制动底板、两个带摩擦衬片的制动 蹄片和定位销组成。制动底板固定在桥壳的旁边,或在转向节旁边。制动鼓安装在轮毅上。在制动 鼓的内表面和制动蹄衬片之间有间隙。制动时,驾驶员踩下制动踏板,制动凸轮推动制动蹄片压在 制动鼓上。制动鼓和摩擦衬片之间的摩擦力制动车轮使汽车停下来。解除制动时,驾驶员松开制动 踏板,回位弹簧拉回制动蹄片,这样车轮可以自由转动。 盘式制动,它用一个金属盘来代替制动鼓。-块平的制动蹄片或制动块安装在制动盘的两侧。 制动蹄片挤压转动的制动盘实现制动。液压主缸的液体推动活塞压向制动盘移动。这个作用推动摩 擦块紧紧地压在制动盘上。在制动蹄片和制动盘之间的摩擦力便车辆减速或停车。这样就提供了制 动作用;活塞是用塑料或金属制成的。通常有三种类型的盘式制动器,它们是浮钳式、固定卡钳式 和移动卡钳式。浮钳式和移动卡钳式的制动盘使用一个分泵。固定卡钳式有两个或四个分泵。 制动系统采用机械液压和气动装置进行制动。所有车辆的驻车制动都使用机械杆件制动。当踩 下制动踏板时,推杆推动制动主缸的活塞压住液体。液体通过管路进入助力制动系统,再进入制动 轮缸。 液体压力推动油缸中的活塞把制动蹄片压向制动鼓或制动盘。 如果放松制动踏板, 活塞回位, 回位弹簧拉回制动蹄片,液体被压回制动主缸,解除制动。 驻车制动的最主要的目的是保持汽车在停车状态下的稳定。 驾驶员在操作独立的驻车制动手柄 时, 驻车制动的机械机构开始工作。 当车辆已经停驶时, 驻车制动通常被使用。拉动杆件后轮制动, 把车辆锁定在该位置上。此时,不用担心车轮会滚动。当驾驶员想要再一次起动汽车时,必须松开 驻车制动拉杆,才可以解除制动。在行车制动失效时,驻车制动也能够把车辆停下来。正是因为这

个原因,·驻车制动与行车制动分离开来,并且采用钢索或杆件代替了液力系统。

Instrument Cluster There are following lights and gauges on the standard instrument panel. All of the warning lights and gauges alert you to possible problems with your car. The following sections detail what each of these indicators means. Brake system light for brakes can show two things—that the parking brake is not fully released, or that the brake fluid level is low in the master cylinder reservoir. If the fluid level is low, the brake system should be checked by a qualified service technician. This light comes on when the parking brake is set or it is not set, it comes on briefly when you turn the ignition key to START. It normally goes off shortly after the engine starts and you release the parking brake, and you must have the hydraulic brake system serviced. The red brake light indicates that the brakes may not be working properly. Brake failure may result in serious personal injury or vehicle damage. Charging system light shown as a battery symbol on your cluster indicates that your battery is not being charged and that you need to have the electrical system checked. This light comes on every time the ignition key is turned to ON or START. The light should go off when the engine is running, otherwise, have the electrical system checked as soon as possible. Upshift indicator comes on to indicate when you should shift your manual transaxle to the next higher gear. This light will help you get better fuel economy by lighting the word SHIFT to signal when you should shift. The blue high beam light comes on when the headlamps are turned to high beam or when you flash the lights. Chime for headlamps sounds if the driver or passenger door is open when the parking lamps or headlamps are on. It sounds until you close the door, turn off the lamps or turn on the ignition. The turn signal indicator lights when you push the turn signal lever up before making a left turn, the left side arrow on the instrument panel flashes. Usually, the turn signals turn off automatically after you turn your car. If the turn signal continues to flash after you have completed the turn, pull the level back to OFF. Service engine soon warning light, located on the instrument, comes on when electronic engine control system is not working properly. If light comes on briefly when you turn the ignition key to ON, but should turn off when the engine starts. If the light does not come on when you turn the ignition to ON or if it comes on and stays on when you are driving, you have your vehicle serviced as soon as possible. This indicates a possible problem with one of the engine's emission control systems. You do not need to have your vehicle towed in. If the light turns on and off briefly while you are driving, it means that the condition is no longer present.

Air bag readiness light illuminates for six seconds when the ignition key is turned to the ON position. If the light fails to illuminate, continues to flash, or remains on, have system serviced as soon as possible. Low washer fluid light illuminates that there is less than a quarter of the container of washer fluid left. Low fuel light comes on when your fuel gauge indicates approximately 1/8 of a tank. Your car must be turned to ON for this light to come on. The fuel gauge displays how much fuel you have in the fuel tank. For proper fuel gauge operation, the ignition switch must be in the OFF position before you add fuel to the fuel tank. The fuel gauge indicator may vary slightly while the vehicle is in motion. This is the result of fuel movement within the tank. An accurate reading may be obtained with the vehicle on the smooth, level ground. Engine coolant temperature gauge indicates the temperature of the fluid in your vehicle's coolant system. The pointer moves from C (cold) into the NORMAL band, if you are driving in heavy traffic or uphill in hot weather, the pointer may reach to the top of the NORMAL band. If the pointer moves out of the NORMAL band, the engine is over heating and may cause engine damages. The speedometer tells you how many kilometers per hour your vehicle is moving. While the odometer tells you the total number of kilometers your vehicle has been driven since the last reset. Press the reset button to return the trip odometer to zero. The tachometer tells you the approximate engine revolutions per minute (how fast the engine is running) . The tachometer is on the left side of the instrument cluster. Driving with the pointer in the red zone may cause engine damage. The main controls for the climate control system, lamps, clock, and radio are all on the instrument panel. If you have radio transmitting equipment in your vehicle, be aware that it can interfere with your vehicle's electrical system and that may cause the instrumentation and convenience products to have temporary, abnormal operation. The engine oil pressure, not the oil level. However, if the engine's oil level is low, it could affect the oil pressure. The light should come on every time your ignition key is turned to On or START, and should go out when the engine starts. If the light stays on or turns on while the engine is running, you have lost oil pressure and continued operation will cause engine damage.
仪表板 在标准的仪表板上有指示灯和指示仪表。 所有的警示灯和仪表都是用来提醒驾驶员汽车可能 遇到的问题。下面具体谈到的是每一种指示所表示的含义。 制动系统指示灯亮,说明有两种情况:驻车制动没有完全松开或制动主缸的制动液面太低。 如果液面太低,应该对制动系统进行技术检测。当驻车制动执行或取消执行时,指示灯会亮 (用 来检测执行动作);当把点火钥匙转到START位置时,指示灯会亮一下。正常情况下,在发动机起 动或松开制动踏板后不久指示灯熄灭, 否则必须进行液压系统的检查。 红色的制动指示灯表明制 动可能不会可靠地工作。制动失效可能会导致严重的人员伤害和车辆破坏。 充电指示灯在仪表板上表示蓄电池的充电量,如果充电指示灯亮,表明蓄电池没有充电,必 须对电路系统进行检测。当点火钥匙转到ON或START位置时,指示灯会亮。当发动机运转时, 指示灯应该熄灭,否则,应该尽快检查电路系统。 加挡指示灯亮, 表明你可以把变速器的挡位提升到下一挡位。 加挡指示灯在驾驶员可以加挡 而末加挡时变亮,有助于充分利用燃油。

当前灯变为远光灯或前灯闪烁时, 蓝色远光灯会发光。 如果在停车灯或前灯发光时车门打开, 会有前灯报警声音。报警声一直延续到把车门关上,熄灭灯光或打开点火开关才会停止。 当驾驶员在左转前将信号器杆件推上去时,左转信号灯亮,仪表板上向左的箭头闪烁。通常 完成车辆的转向后转向信号灯会自动熄灭。如果在完成转向后,转向信号灯连续闪烁,则需要将 信号器杆件拉回OFF位置。 当发动机电子控制系统不能有效地工作时, 在仪表板上的发动机故障灯会亮。 当点火钥匙转 向ON位置时指示灯应该短暂地亮一下,在发动机起动时应该熄灭。如果点火钥匙转到ON位置时 灯不亮,或在车辆行驶过程中保持亮,则应该尽快对车辆进行维修,这表明可能发动机排放控制 系统出现故障,这时还不需要拖车。如果在驾驶过程中指示灯短暂地闪烁,说明车辆的性能己经 出现问题。 当点火钥匙被转向ON位置时,安全气囊指示灯亮六秒。如果这个指示灯不亮、一直闪烁或 不熄灭,则应赶快维修系统。 清洗液指示灯发光,表明剩下的清洗液不足容器的四分之一。 当燃油表显示油箱中的燃油大约为油箱容积的八分之一时,燃油指示灯会亮。当然,只有在 汽车发动的情况下, 这个灯才会亮。 燃油表可以显示出油箱中有多少燃料。 为了油表的准确工作, 在向油箱中加入燃油时, 点火开关必须在OFF位置。 在车辆运动过程中, 燃油表会有轻微的改变, 这是油箱内燃料运动的结果。当汽车在于整的路面上行驶时可以获得准确的数值。 发动机水温表显示车辆冷却系统内液体的温度。如果在大热天交通拥挤或爬坡的环境下行 驶,指针会从C(COLD)向NORMAL移动,甚至可以达到NORMAL的最上端。如果指针移出正常 的范围,则说明发动机过热,这会引起对发动机的损坏。 车速表用来显示车辆正在行驶的时速。里程表则显示自上一次设置(归零)后车辆行驶的总 里程。按重新设定按钮可以将里程计归零。 转速表用来显示发动机的大约转数 (发动机运转得有多快)。转速表在仪表板的左侧。当指 针指向红色区域时,如果继续保持车辆运行,则会造成对发动机的损坏。 空调控制系统、灯、时钟和收音机全部都在仪表板上。 如果汽车上安装有传输信号的无线电设备,则应该意识到它可能会干扰汽车电子系统,而 这将导致车载仪器和机械产品暂时的非正常工作。 发动机机油压力并不是指示发动机机油平面(高低)。然而,如果发动机机油平面较低,将 会影响机油压力。当点火开关转到ON或STA RT位置时,指示灯都应该亮,在发动机起动后熄 灭。如果在发动机运转时指示灯长亮或点亮,则说明机油压力过低,此时若继续运行将会导致对 发动机的损坏。


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