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1、汽车工程专业英语,李俊玲 罗永革版（原文与翻译）,todays average car contains more than 15000 separate,individual parts that must worktogether.these parts can be grouped into four major categories:body,engine,chassis and electricalsystem.,现在的汽车一般都由 15000 多个分散、独立且相互配合的零部件组成。这些零部件只要分为,四类：车身、发动机、底盘和电气设备。,an automobile body is
2、a sheet metal shell with windows,a hood and a trunk deck built into it.itprovides a protective covering for the engine,passengers and cargo.the body is designed to keeppassengers safe and comfortable.the body styling provides an attractive,colorful modernappearance for the vehicle.,轿车车身是一个钣金件壳体，它上面有
3、车窗、车门、发动机罩和行李舱门等部件，它给发动机、乘客和行李提供防护。车身设计是为了确保乘客乘坐的安全和舒适。车身造型设计使得汽车有一个华美、现代、吸引人的外观。,a sedan has an enclosed body with a maximum of 4 doors to allow access to the passengercompartment.the design also allows for storage of luggage or other goods.a sedan can also bereferred to as a saloon and traditional
4、ly has a fixed roof.there are soft-top versions of the samebody design except forhaving 2 doors,and there are commonly referred to as convertibles.轿车车身为封闭式，轿车最多有 4 个车门，乘员通过车门进出。另外车身的设计还应考虑行,李和货物的存放。传统的轿车都是硬顶车身。活顶乘用车（敞篷车）的车顶是软顶，车身设计与普通轿车类似，但只有两个车门。,the utility or pick-up carries goods.usually it has
5、stronger chassis components and suspensionthan a sedan to support greater gross vehicle mass.,皮卡一般用来运载货物。为能承载更大的总质量，皮卡的底盘部件和悬架比轿车更结实。,light vehicle vans can be based on common sedan designs or redesigns so that maximum cargospace is available.,轻型货车一般是基于普通轿车设计的，或是重新设计使可用载货空间最大化。,the bodies of commerc
6、ial vehicles that transport goods are designed for that specificpurpose.tankers transport fluids,tippers carry earth or bulk grains,flatbeds and vans are used forgeneral goods transport.,用于运输货物的商用车车身必须满足具体要求，例如运输液体的油罐车、运输泥土或散装谷物的自卸车、运输一般货物的平板车或货车。,buses and coaches are usually 4-wheel rigid vehices,
7、but a large number of wheels and axles canbe used.sometimes articulated buses are used to increase capacity.buses and coaches can besingle-deck or double-deck.buses are commonly used in cities as commuter transports whilecoaches are more luxurious used forlong distances.,客车和长途汽车一般是有 4 个车轮的整体式车辆，也能配备
8、更多的车轮和车桥。为了增加客,车的载客量往往使用由铰链连接的客车。公共汽车和长途汽车有单层和双层两种。公共汽车一般用城市内公共交通，而长途汽车一般用于长距离的旅行。,1.2 Engine,The engine acts as the power unit.The internal combustion engine is most common:this,obtains its power by burning a liquid fuel inside the engine cylinder.There are two types of,engine:gasoline,(also,called
9、,a,spark-ignition,engine),and,diesel(also,called,a,compression-ignition engine).Both engines are called heat engines;the burning fuel generatesheat which causes the gas inside the cylinder to increase its pressure and supply power to rotatea shaft connected to the power train.发动机作为动力设备，常见的类型是内燃机，其原理
10、是通过发动机缸内的液体燃料燃烧而产生能量。发动机可分为两类：汽油机（点燃式）和柴油机（压燃式），都属于热力发动机。燃料燃烧产生热量使缸内气体气压上升，从而产生能量，驱动与动力传动系相连接的轴旋转。The way engine cylinders are arranged is called engine configuration.In-line engines have thecylinders in a line.This design creates a simply cast engine block.In vehicle applications,thenumber of cylin
11、ders is normally from 2 up to 6.Usually,the cylinders are vertical.As the numberof the cylinders increase,the length of the block and crankshaft can become a problem.One wayto avoid this is with a V configuration.This design makes the engines block and crankshaft shorterand more rigid.发动机的布置即发动机气缸的排
12、列方式。发动机缸体按直线排列的即直列式，这种布置使得发动机缸体结构简单。汽车发动机一般为 26 缸，通常气缸是垂直放置的，但气缸数量的增加会导致缸体和曲轴的长度过大，解决问题的措施之一就是采用 V 型布置，这种布置方式可以使发动机缸体和曲轴长度尺寸更短，从而大大增加刚度。An engine located at the front can be mounted longitudinally and can drive either the front orthe rear wheels.Rear engine vehicles have the engine mounted behind th
13、e rear wheels.Theengine can be transverse or longitudinal and usually drives the rear wheels only.前置发动机可以纵向布置，能够驱动前轮或后轮。后置发动机布置在后轮后侧，发动机即可纵向布置又可横向布置，一般只能驱动后轮。1.3 chassis 底盘the chassis is an assembly of those systems that are the major operating parts of a vehicle.thechassis includes the power train,
14、steering,suspension,and braking systems.底盘由汽车的主要操作系统组装而成。包括传动系、行驶系、转向系和制动系四部分。1）Powertrain system conveys the drive to the wheels.传动系-将驱动力传递到车轮。2）Steering system controls the direction of movement.转向系-控制汽车的行驶方向。3）Suspension and wheels absorbs the road shocks.悬挂系-吸收路面震动4）Brake slows down the vehicle.
15、制动系-使汽车减速缓行。1.3.1 power train system 动力传动系统The power train transfers turning effort from the engine to the driving wheels.a power train can include a clutch manual transmission or a torque converter for automatic transmission,a drive shaft,final drive and differential gears and driving axles.Alterna
16、tively,a transaxle may be used.A transaxle is a self-contained unit with a transmission,final drive gears and differential located in one casing.传动系把发动机输出的扭矩传递给驱动轮。传动系包括离合器（对应机械变速器）或液力变矩器（对应液力自动变速器）、变速器、驱动轴、主减速器、差速器和驱动桥。另外有些传动系采用由变速器、主减速器和差速器组成的一体式的变速驱动桥。（或者采用一个独立的变速驱动桥，即变速器在同一个箱体内。）A vehicle with a
17、 manual transmission uses a clutch to engage and disengage the engine from thepower train.Engine torque is transmitted through the clutch to the transmission or transaxle.thetransmission contains sets of gears that increase or decrease the torque before it is transmitted,to the rest of the power tra
18、in.the lower the gear ratio selected,the higher the torquetransmissioned.a vehicle starting from rest needs a lot of torque,but once it is moving,it canmaintain speed with only a relatively small amount of torque.a higher gear ratio can then beselected,and engine speed is reduced.,对于采用机械变速器的汽车，其发动机扭
19、矩由离合器传递给变速器或变速驱动桥，并通过离合器来控制发动机和传动系的啮合或分离。变速器包含了不同传动比的齿轮副，能够增加或减小扭矩。选择的齿轮速比越小，传递的扭矩最大。汽车起步时需要较大的扭矩，一旦起动后，仅需要较小的扭矩就可维持速度，此时应该换用较高的档位，以降低发动机转速。,a conventional vehicle with the engine at the front and driving wheels at the rear uses a driveshaft,called a propeller shaft,to transmit torque from transmiss
20、ion to the final drive.,传统的汽车采用前置发动机、后轮驱动，因此需要传动轴把动力从变速器传递给主减速器。,the final drive provides a final gear reduction to multiply the torque before applying to thedriving axles.on front engine rear wheel drive vehicles,the final drive changes the direction ofdrive by 90 degrees.inside the final drive,a d
21、ifferential gear set divides the torque to the axlesand allows for the difference in speed of each wheel When cornering.axles shafts transmit thetorque to the driving wheels.in a rear-wheel drive vehicle,the axles can be solid or contain jointsto allow for movement of suspension.for a front-wheel dr
22、ive vehicle,the drive shaft has universaljoints to allow for suspension and steering movement.,主减速器的作用就是在把动力传递给驱动轮之前，降低转速并增加扭矩。对于前置后驱的汽,车，主减速器还将驱动的旋转方向改变了 90 度。主减速器内的差速器齿轮副，把动力分给,两个驱动轴，并允许两边车轮在转向时具有不同的转速。动力最终由驱动轴传递给车轮。后轮驱动汽车的驱动桥应能满足悬架的运动，可以是刚性的或包含运动副。为满足悬架和转向的要求，前轮驱动汽车驱动轴上需安装万向节。,an automatic transm
23、ission or transaxle performs similar functions to a manual transmission ortransaxle except that gear selection is controlled either hydraulically or electronically.theautomatic transmission uses a torque converter,which acts as a hydraulic coupling to transfer thedrive.,自动变速器或自动变速驱动桥的功能和机械式基本类似，区别在于
24、档位的选择是液力或电力控制的。液力自动变速器采用液力变矩（耦合）器作为连接器以传递动力。,1.3.2 steering system 转向系统,The directional motion of vehicle is controlled by a steering system.A basic steering system has 3main parts:a steering box connected to the steering wheel,the linkage connecting the steeringbox to the wheel assembly at the fron
25、t wheels and front suspension parts to let the wheelassemblies pivot.When the driver turns the steering wheel,a shaft from the steering columnturns the steering gear.The steering gear moves tie-rods that connect to the front wheels.Thetie-rods move the front wheels to turn the vehicle right or left.
26、,转向系控制汽车行驶方向，一般由三部分组成：与转向盘相连的转向器、连接车轮和转向器的传动结构、允许车轮转动的前悬架部件。当驾驶员转动方向盘时，转向柱内的轴带动转向器运动，然后通过转向传动机构来转动车轮，从而使得汽车向左或向右行驶。,1.3.3 suspension system 悬架系统,The purpose of the complete suspension system is to isolate the vehicle body from road shocksand vibrations,which will otherwise be transferred to the pass
27、engers and load.It must also keepthe tires in contact with the road regardless of road surface.A basic suspension system consistsof springs,axles,shock absorbers,arms,rods and ball joints.,整个悬架系统的作用是隔离来自路面的冲击和振动对车身的影响，防止传递给乘员和货物。另外不论路面如何，悬架系统都应该保持轮胎和路面接触。悬架系统的基本组成包括弹性元件、车桥、减震器、杆系（臂、杆）和球副组成的导向机构。,the
28、 spring is the flexible component of the sussuspension.basic types are:leaf spring,coil springand torsion bars.modern passenger vehicles and can have coil springs at the front and leafsprings at the rear.heavy commercial vehicles usually use leaf springs or air suspension.,弹簧是悬架的弹性元件，常见的弹簧类型有：钢板弹簧、螺
29、旋弹簧和扭杆弹簧。现代汽车大多采用小的螺旋弹簧，轻型商用车常采用的螺旋弹簧比一般乘用车的大得多，或者前悬架采用螺旋弹簧，后悬架采用钢板弹簧。重型商用车则通常采用钢板弹簧或空气弹簧。,wheels must be strong enough to support the vehicle and withstand the forces caused by normaloperation.at the same time,they must be as light as possible to help keep unsprung weight to aminimum.,车轮必须能支撑整车重量，并
30、能承受正常工况下的载荷。同时车轮必须尽可能地轻，有助于最小化簧下质量。,wheels can be made from pressed-steeling two sections,and also be made from cast aluminiumalloy.alloy wheels are popular because of their appearance and because they are lighter thansimilar steel wheels.aluminium is a better conductor of heat,so alloy wheels can d
31、issipate heatfrom brakees and tires more effectively than steel ones.,车轮可采用双面钢化板压制而成，也可采用铸造的铝合金材料。除了外观漂亮之外，铝合金比钢更轻，因此铝合金车轮应用较广。另外铝合金导热性更好，因此相比钢制车轮，制动器和车轮产生的热量更容易被铝合金车轮散发。,the tire provides a cushion between the vehicle and the road to reduce the transmission of roadshocks.it also provides friction t
32、o allow the vehicle to perform its normal operations.modern tiresare manufactured from a range of materials.the rubber is mainly synthetic.two types of tireconstruction are common:cross-ply and radial.most passenger cars now use radial tires,andradials are replacing cross-ply tires on 4-wheel drives
33、 and heavy vehicles.,轮胎在汽车和路面之间起缓冲作用，能减小路面冲击。同时轮胎也提供了车轮正常行驶所需的摩擦力。轮胎是由多种材料加工而成，橡胶多是人工合成的。最常见的轮胎类型是子午线轮胎和斜交轮胎。现在大部分乘用车都采用子午线轮胎，在四轮驱动和商用车上，子午线轮胎也正在取代斜交胎。,tube tires require an inner tube to seal air inside the tire.tubeless tires are eliminating the innertube by making the complete wheel and tire asse
34、mbly airtight.a special airtight valve assembly isneeded.this can be tight fit into the rim or can be held with a nut and sealing washers.,有内胎的轮胎用内胎来密封内部气体。无内胎的轮胎则要求车轮和轮胎具有很好的密封性，这就需要专用的密封件，可以紧固在轮缘上，也可用螺钉和密封圈来固定。,1.3.4 Braking system 制动系统,Drum brakes have a drum attached to the wheel hub,and braking
35、 occurs by means of brakeshoes expanding against the inside of the drum.With disc brakes,a disc attached to the wheelhub is clenched between two brake pads.on light vehicles,both of these systems are hydraulicallyoperated.the brake pedal operates a master cylinder.hydraulic lines and houses connect
36、themaster cylinder to brake cylinders at the wheels.most modern light vehicles have either discbrakes on the front wheels and drum brakes on the rear or disc brakes on all 4 wheels.disc brakesrequire greater forces to operate them.a brake booster assist the driver by increasing the forceapplied to t
37、he master cylinder when the brake is operated.,鼓式制动器的制动鼓和轮毂连接，制动蹄张开压紧制动鼓内侧从而产生制动。在盘式制动器上，连着轮毂的制动盘被紧紧夹在两个制动块之间。轻型汽车上都采用液压制动系统，制动踏板控制制动主缸，通过液压管路与车轮上的制动轮缸相连。现在轻型汽车上的制动器，前轮采用盘式，后轮采用鼓式，或全部采用盘式。相比鼓式制动器，盘式制动器需要更大的作用力。在制动时采用增压器辅助驾驶员提高施加在主缸上的制动力。,air operated braking systems are used on heavy pressed air ope
38、rating on largediameter diaphragms provides the large forces to the brake assembly that are needed.an aircompressor pumps air to storage tanks.driver controlled valves then direct the compressed air todifferent wheel units to operate the friction brakes.on articulated vehicles,any delay in applyingt
39、he trailer brake should be minimize.this is achieved by using a relay valve and a separatereservoir on the trailer.this arrangement also applies the brakes if the trailer disconnected fromthe prime mover.,重型商用车多采用气压制动系统，压缩气体作用在直径较大的膜片上时能为制动总成提供较大的制动力。气压制动系统靠空气压缩机把气体吸入储气罐。驾驶员控制阀门开启，使压缩气体进入车轮制动气室进行制动。
40、在铰接车辆的拖车上采用继动阀和单独的储气罐，以减小拖车制动系统的时间延迟，这种布置方式还可以在拖车失去动力时制动拖车。,all vehicles must be fitted with at least 2 independent systems.they were once called theservice brake and the emergency brake.now they are usually referred to as the foot brake and thepark brake.most light vehicles use a foot brake that op
41、erates through a hydraulic system on allwheels and a hand operated brake that acts mechanically on the rear wheels only.one commonuse of the hand brake system is to hold the vehicle when it is parked.the system are designed tobe independent So that if one fails,the otheris still available.,所有汽车必须安装至
42、少两套独立的制动系统，即行车制动系统与紧急制动系统，一般被称之为脚制动和停车制动。大部分轻型汽车的脚制动通过液压系统作用在四个车轮上，而其手制动则是机械式的，且仅作用在后轮。手制动的一个普通用途就是停车时对汽车进行制动。设计两套独立的制动系统的目的就是当一套失效时，另一套仍可工作。,1.4.1 Electrical system 电器系统,The electrical system supplies electricity for the starter,ignition,lights and heater.The electricitylevel is maintained by a cha
43、rging circuit.,电器系统为起动机、点火系、照明和加热设备提供电流，电流的大小由充电电路来维持。,The charging system provides electrical energy for all of the electrical components on thevehicle.the main parts of the charging system include:the battery,the alternator,the voltageregulator which is usually integral to the alternator,a chargin
44、g warning or indicator light andwiring that complete the circuits.the battery provides electrical components of the vehicle.it alsocharges the batter to replace the energy used to start the engine.the voltage regulator preventsovercharging.,充电系统为汽车上所有的电器系统提供电能。充电系统主要组成部分有：蓄电池、交流发电机、稳压器（多集成在发电机中），充电指
45、示灯和组成电路的电线。汽车起动时由蓄电池提供能量，一旦发动机开始工作，交流电机为电气设备供电，同时还对蓄电池进行充电，以补偿起动所消耗的电能。稳压器则防止过载。,1.4.2 Starting 启动系统,The staring system consists of the battery,cables,starter motor,flywheel ring gear and the ignitionswitch.during starting,two actions occur.the pinion of the starter motor engages with theflywheel ri
46、ng gear and the starter motor then operates to crank the engine.the starter motor is,an electrical motormounted on the engine block and operated from the battery.,起动系统包括电池、电缆、启动电机、飞轮齿圈和点火开工。起动需要两个动作，启动电机齿轮和飞轮齿圈啮合，从而带动发动机转动。起动电机安装在发动机壳体上，靠电池工作。,1.4.3 Ignition 点火系统,A basic ignition system consists of
47、the battery,low-tension cables,the ignition coil,distributor,coilhigh-tension cable,spark pluk cables and spark plugs.the ignition system provides high intensesparks to spark plugs to ignite the fuel charges in the combustion chambers.the sparks must besupplied at the right time and they must have s
48、ufficient energy over a range of conditions toignite the charges.the energy comes from the battery and alternator,and voltage is increased bythe ignition coil.the system has two circuits.the primary or low-tension circuit initiates thespark.the secondary or high-tension circuit produces the high vol
49、tage and distributes it to sparkplugs.,点火系统包括电池、低压电缆、点火线圈、分电器、高压电缆、火花塞连线和火花塞。点火系统在火花塞处产生高压火花，点燃发动机燃烧室内的燃油混合物。点火系统必须在恰当的时刻提供火花，并且能量满足各种工况的要求。电池和交流发电机为点火系统供电，点火线圈提高电压。点火系统由两级电路组成，初级电路（低压电路）初始化火花，次级电路（高压电路）产生高压电，并分到各个火花塞。,2.1 principle of operation 工作原理2.1.1 energy and power 能源和动力,Engine is used to pro
50、duce power.The chemical energy in fuel is converted to heat by theburning of the fuel at a controlled rate.This process is called combustion.If engine combustionoccurs with the power chamber.,the engine is called internal combustion engine.If combustiontakes place outside the cylinder,the engine is
