《汽车工程专业英语》复习重点

1、Todaysaveragecarcontainsmorethan15,000separate,individualpartsthatmustworktogether.Thesepartscangroupedintofourmajorcategories:engine,body,chassisandelectricalequipment.1layoutThebodylayoutofapassengercarisdesignedtokeeppassengerssafeandcomfortable.Thebodystylingprovidesanattractive,colorful,moderna

2、ppearanceforthevehicle.1.1汽车车身的设计还应该保证乘员的安全舒适。车身的造型（款式）使得汽车看起来漂亮迷人、色彩斑斓、时尚前卫。Theengineactsasthepowerunit.Theinternalcombustionengineismostcommon:thisobtainsitspowerbyburningaliquidfuelinsidetheenginecylinder.Therearetwotypesofengine:gasoline（alsocalledaspark-ignitionengine）anddiesel（alsocalledacompr

3、ession-ignitionengine）.Bothenginesarecalledheatengines;theburningfuelgeneratesheatwhichcausesthegasinsidethecylindertoincreaseitspressureandsupplypowertorotateashaftconnectedtothepowertrain.1.2发动机作为动力设备，常见的类型是内燃机，其原理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压上升，产生的能量驱动轴旋转，

4、并传递给动力传动系。Thechassisincludesthepowertrain,steering,suspension,andbrakingsystems.1.3Powertrainsystem:conveysthedrivetothewheelsSteeringsystem:controlsthedirectionofmovementSuspensionandwheelsabsorbtheroadshocksBrakingslowsdownthevehicleThepurposeofthecompletesuspensionsystemistoisolatethevehiclebodyf

5、romroadshocksandvibrations,whichwillotherwisebetransferredtothepassengersandload.Itmustalsokeepthetiresincontactwiththeroadregardlessofroadsurface.Abasicsuspensionsystemconsistsofsprings,axles,shockabsorbers,arms,rodsandballjoints.1.3.3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

6、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。Drumbrakeshaveadrumattachedtothewheelhub,andbrakingoccursbymeansofbrakeshoesexpandingagainsttheinsideofthedrum.Withdiscbrakes,adiscattachedtothewheelhubisclenchedbetweentwobrakepads.1.3.4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。Linking

7、thepistonbyaconnectingrodtoacrankshaftcausesthegastorotatetheshaftthroughhalfaturn.2.1.2活塞通过连杆和曲轴连接，使得气体带动曲轴旋转半圈。Whenavehicleistobemovedfromresttheclutchmustengageastationarygearboxshaftwiththeengine;thismustberotatingatahighspeedtoprovidesufficientpowerorelsetheloadwillbetoogreatandtheenginewillsta

8、ll（cometorest）.3.2.1当汽车原地起步时，离合器要将静止的变速器轴同发动机接合起来，此时发动机必须高速旋转以提供足够大的功率，否则载荷过大将引起发动机熄火。Thedrivingmember:Thedrivingmemberconsistsoftwoparts:theflywheelandthepressureplate.Theflywheelisbolteddirectlytotheenginecrankshaftandrotateswhenthecrankshaftturns.Thepressureplateisboltedtotheflywheel.Theresultist

9、hatbothflywheelandpressureplaterotatetogether.主动部分由飞轮和压盘两部件组成。飞轮用螺栓直接连接到发动机曲轴上，随曲轴旋转而旋转。压盘与飞轮连接，这样飞轮和压盘一起旋转。Thedrivenmember:Thedrivenmember,orclutchdisc,islocatedbetweentheflywheelandpressureplate.Thedischasasplinedhubthatlockstothesplinedinputshaftonthegearbox.Anyrotationoftheclutchdiscturnstheinpu

10、tshaft.从动部分（或从动盘）位于飞轮和压盘之间。从动盘上有花键毂，连接着变速器上带花键的输入轴。从动盘的旋转带动变速器输入轴随之转动。Thedrivenmember:Theinnerpartoftheclutchdisc,calledthehubflange,hasanumberofsmallcoilsprings.Thesespringsarecalledtorsionalsprings.Theyletthemiddlepartoftheclutchdiscturnslightlyonthehub.Thus,thespringsabsorbthetorsionalvibrationso

11、fthecrankshaft.Whenthespringshavecompressedcompletely,theclutchmovesbackuntilthespringsrelax.Inotherwords,theclutchabsorbstheseenginevibrations,preventingthevibrationsfromgoingthroughthedrivetrain.当从动盘的内侧（毂缘）有一些叫作扭转弹簧的小螺旋弹簧，这些弹簧使得从动盘中部相对从动盘毂能有轻微转动，从而吸收曲轴的扭转振动。压紧弹簧完全压缩时，离合器向后移动直到弹簧开始伸张为止。也就是说，离合器吸收发动

12、机的振动，防止振动传递给传动系。operatingmembers:Thesearethepartsthatreleasepressurefromtheclutchdisc.Theoperatingmembersconsistoftheclutchpedal,clutchreturnspring,clutchlinkage,clutchfork,andthrowoutbearing.Theclutchlinkageincludestheclutchpedalandamechanicalorhydraulicsystemtomovetheotheroperatingmembers.操纵机构释放离合

13、器盘的压力。操纵机构由离合器踏板、回位弹簧、离合器杆系、分离叉和分离轴承等组成。离合器杆系包括离合器踏板以及用来操纵其它部件的机械式或液压式操纵系统。operatingmembers:Whentheclutchpedalisdepressed,theclutchlinkageoperatestheclutchfork.Theclutchfork,orreleasefork,movesthethrowoutbearingagainstthepressureplatereleaselevers.Theseleversthencompressspringsthatnormallyholdtheclu

14、tchdisctightlyagainsttheflywheel.踩下离合器踏板，离合器杆系操纵分离叉。分离叉带动分离轴承压向压盘上的分离杠杆，分离杠杆压缩压紧弹簧。通常情况下，压紧弹簧使从动盘和飞轮紧密接合。operatingmembers:Whentheclutchpedalisreleased,thepressureplateforcestheclutchdiscagainsttheflywheel.Theclutchreturnspringhelpsraisethepedal.释放离合器踏板，压盘使从动盘同飞轮接合，回位弹簧使离合器踏板抬起。Therearethreetypesofma

15、nualtransmissionsSliding-meshTransmission、Constant-meshTransmission、Synchro-meshTransimission。3.3.1Inthecaseofasliding-meshgearbox,gearchangingdemandsskillifnoiseistobeavoided.Crashing(orclashing)ofthegearsastheresultofabadchangesuggeststhereasonwhythistypeisoftencalledacrashtypegearbox.对滑动啮合变速器来说，换

16、挡时要避免噪声是需要技巧的。齿轮打齿是由换挡不当引起的，这也是滑动啮合变速器经常被称为“碰撞”型变速器的原因。MT:ManualTransmissionAMT:AutomaticMannuallyTransmissionsCVT:ContinuouslyVariableTransmissionsAT:AutomaticTransmissionThesuspensionconnectsthefinaldriveassemblytothecarbody.Thefinaldrivemovesupanddowninrelationtotheengineandtransmission.Acoupling

17、isneededthatpermitsmovementbetweenthefinaldriveandtransmission.Theuniversaljoints(U-joints)andslidingjointsFig.3-8providethiscoupling.3.4.2悬架连接着主减速器总成和车身。主减速器相对于发动机和变速器上下运动，这样在主减速器和变速器之间就需要万向节和滑动联轴节等连接装置来允许其相对运动。Therearetwotypesofuniversaljointscrosstypejointandconstant-velocityuniversaljoint.Heretw

18、oU-shapedpiecesareplacedperpendiculartooneanotherandjoinedwithasimplecrossFig.3-16.TheU-shapedpiecesarecalledyokes.Thecrossthatconnectsthemiscalledaspider.Thearmsthatextendfromthespiderarecalledtrunnions.Thetwoyokesareata90angletooneanother.Mostcarshavetwouniversaljoints,oneateachendofthepropellersh

19、aft.两个U形片垂直布置，通过十字叉连接在一起。U形片称为万向节叉，连接万向节叉的十字叉叫作十字轴，从十字轴延伸出的臂叫作耳轴，两个万向节叉成90布置。多数汽车采用两个万向节，在传动轴的每一端各有一个万向节。Ashaftwhichreceivesthedrivefromacrosstypejointvariesitsspeedduringrotation;thegreaterthedriveanglethegreaterthespeedvariation.Aconstantrotationalspeedcanberestoredbyfittingasecondjointinawaysucht

20、hatwhenthefirstjointincreasesitsspeedthesecondjointdecreasesitsspeed.传动轴接收十字轴式万向节传来的动力，转动时其速度发生变化。传动角越大，速度变化越大。要实现等速，必须以某种方式安装第二个万向节，这样第一个万向节使转速增大，第二个万向节就使转速减少。Largecrownwheelsreducethegroundclearanceunderthedifferential.Inthecaseofpinionaxlesandplanetaryhubreductionaxles,thedifferentialandthehalf-s

21、haftscanbemadesmallerbysplittingthereduction.Thismakesitpossible,eveninthecaseofhighpoweroutputs,toachievesufficientgroundclearanceofthevehicle.从动锥齿轮尺寸大，就降低了汽车的离地间隙。如果采用圆柱齿轮式和行星齿轮式轮边减速器，通过两级减速的形式可极大减小差速器和半轴的尺寸。这样，汽车就可以获得足够大的离地间隙，即使输出功率要求较大也可以。Planetarygearsareusedmainlyinfinaldrives,rear-mountedspli

22、tterboxesand,aboveall,inautomatictransmissions.Thesimplestformofplanetarygear(theplanetary-geartrain)consistsofsungear,ringgearandarmwithplanetgears.Eachofthethreeelementsmayactasdrive,outputormaybeatrest.Therefore,greatvariationispossibleasregardsthetransmissionratio,rangingasfarasareversalofthedir

23、ectionofrotation.Theparallelmeshingofseveralgearsunderloadpermitsacompactconstruetion.行星齿轮系主要应用在主减速器、后置副变速器和自动变速器上。最简单的行星齿轮系统由太阳轮、齿圈和行星轮组成。三部件中任意一个都可作输入、输出或保持静止。这样，依照变速比的不同可得到较大的变速范围，汽车的倒行也能实现。承载齿轮的平行啮合使行星轮系结构较紧凑。Whenavehicleiscorneredtheinnerwheelmovesthroughashorterdistancethantheouterwheel.Thisme

24、ansthattheinnerwheelmustslowdownandtheouterwheelmustspeedup.Duringthisperioditisdesirablethateachdrivingwheelmaintainsitsdrivingaction.Thedifferentialperformsthesetwotasks.3.6当汽车转弯时，内侧车轮比外侧车轮行驶的距离要短，这说明内侧车轮比外侧车轮转得要慢。在此期间，维持每个驱动车轮的行驶状态是很重要的。这两个任务由差速器来完成。Whenthevehicleistravellingstraight,theleverwill

25、dividethedrivingforceequallyandbothdiscswillmovethesameamount.Whenthevehiclecorners,thedrivingforcewillstillbedividedequallybuttheinnerdiscwillnowmovethroughasmallerdistance;thiswillcausethelevertopivotaboutitscenterwhichwillprizeforwardtheouterdisctogiveitagreatermovement.Thisactionshowsthatthetorq

26、ueappliedtoeachdrivingwheelisalwaysequalhencethedifferentialissometimescalledatorqueequalizer.汽车直行时，杠杆平均分配驱动力，两个圆盘移动相同的距离。汽车转弯时驱动力仍然会平均分配，但是内侧圆盘移动的距离要小一些，这使得杠杆绕中心转动，推动外侧圆盘使之移动更大的距离。这个过程表明扭矩总是平均分配给每个驱动轮，因此差速器有时也叫做扭矩平衡装置。Energyisrequiredwhenavehicleisacceleratedfromresttoacertainspeed.Aproportionoftha

27、tenergyisnowstoredinthevehicleandiscalledkineticenergy.Inordertoreducethespeedofthevehicle,thebrakeshavetoconvertthekineticenergytoheatenergy;thespeedofconversiongovernstherateatwhichthevehicleslowsdown.4.1汽车从原地起步加速到某一速度需要能量。储存在汽车中的那部分能量称为动能。要降低车速，制动器必须把汽车的动能转换为热能；转换的速度决定了汽车减速的快慢。Abrakingsystemconsi

28、stsofanenergysupplyingdevice,acontroldevice,atransmissiondeviceandthebrake.Thethreetypesofbrakingsystemsareinusetoday:servicebrakingsystem,parkingbrakingsystemandadditionalretarding-brakingsystem.目前使用的制动系统有三种类型：行车制动系，住车制动系和辅助制动系.Twotypesofbrakesareusedinmoderncars:drumbrakesanddiscbrakes.目前使用的制动器有两种

29、类型：鼓式制动器和盘式制动器.Twotypesofhydraulicbrakesystemsareused.1、Themanualbrakesystemisthesimples.2、Thepowerbrakesystem.Exposedtotheair,discbrakesradiatetheheattotheairbetterthandrumbrakes:Thismeansthatthebrakecanbeoperatedcontinuouslyforalongerperiod,i.e.theyhaveagreaterresistancetofade(fall-offinbrakeeffic

30、iencyduetoheat).4.2.2由于暴露于空气中，盘式制动器的散热效果比鼓式的要好：这意味着盘式制动器能持续使用更长的时间，也就是说其抗热衰退性(因受热导致制动效能下降)要好得多。Discbrakesasusedinmostpassengercarsareslowlybeginningtobeusedincommercialvehiclesaswell.Asidefromtheiruseinfastcoaches,currentuseofdiscbrakesincommercialvehiclesisprimarilylimitedtofront-axlebrakesforcomme

31、rcialvehiclesuptoaweightofapprox.7.5twhicharedriveninamannersimilartopassengercars.常用在许多乘用车上的盘式制动器正逐渐被用于商用车它们除用于快速客车外，目前盘式制动器在商用车上的用途基本限制在前轴制动，因为商用车重量约等于7.5吨时驱动方式与乘用车相似TherearetwomainwaysofbuildingautomobilesTheyarebuiltusingbody/frameconstructionandunitizedbodyconstruction.Aseparateframemustbelight

32、yetstrongenoughtoresistthevariousloadsandroadforces.Commercialvehiclesnormallyuseaseparatesteelframetoprovidetherigidityneededtosupportthevariousloads.Thetwolongsidemembersofchannelsectionarerivetedtoanumberofcrossmemberstogivealowweightframewhichoffersgreatresistancetobending,twisting.4.9分离式车架必须足够轻

33、巧而且结实，以承受变化的载荷和路面作用力。商用车通常使用分离式钢质车架，以获得较好的刚度来承受变化的载荷。两根槽形的长纵梁铆接着很多横梁，这使车架重量较轻，具有较好的抗弯和抗扭能力。Mostcarsuseaunitizedbodyconstruetion,acombinedbodyandframe.Unitizedbodyconstruetionislighterthanbody/frameconstruetion,butnoisier.Rubbermountsareusedbetweenthebodysectionandmechanicalpartstoabsorbvibrations.Th

34、efloorpanismadeofsectionsthatsupporttherearsuspensionandthetransmission.多数轿车采用承载式车身，也就是车身和车架融为一体。承载式车身比非承载式车身质量轻，但噪声大。在车身和机械部件之间安装橡胶块以吸收振动。地板由一些支撑后悬架和变速器的部件组成。Thepurposeofventingsystemsistodrawinfreshairandremovestaleairfromtheinteriorofthecar.Freshairventingsystemsdirectairtotwodifferentplaces.Firs

35、t,theycandirectoutsideairintotheheaterhousing.Thisaireithercanbypassthecoiloritcanbeheatedbythecoil.Second,theaircanmovedirectlyintothepassengercompartmentthroughsmallventdoorsinthedashpaneloratfloorlevel.Ventingalsocantakeplacebyopeningthewindows.通风系统吸入新鲜的空气，排除车内不新鲜的空气。通风系统将新鲜空气引入两个地方。首先，通风系统将外部空气引

36、入加热器壳里，空气从线圈旁流过或被线圈加热。其次，空气可通过前围板或地板上的小风门直接将空气引入车厢打开车窗也可实现通风。Thebasicsteeringsysteminmostcarsisthesame.Thesteeringgearofsteeringboxistheheartofthesteeringsystem.Thisusuallyisnexttotheengine.Ashaftextendsfromthebackofthesteeringgear.Thisshaftisconnectedtothesteeringcolumnorsteeringshaft.Thesteeringwh

37、eelisatthetopofthesteeringcolumn.Anothershaftcomesfromthebottomofthesteeringgear.Thisshaftconnectstothearms,rods,andlinks.Thispartsassembly,calledthesteeringlinkage,connectsthesteeringgeartothepartsatthewheels.Thewheelsandtiresmounttothesteeringknuckles.AsshowninFig.5-1,theknucklesarepivotedatthetop

38、andbottom.Thus,thewheelsandtirescanturnfromsidetoside.5.1多数汽车的转向系基本上是一样的。转向系的核心是转向器，一般位于发动机附近。一根轴从转向器后部伸出，连接着转向柱。方向盘在转向柱的顶端。另一根轴从转向器低端伸出，连接着转向臂、转向拉杆和转向杆系，这些部件总称为转向传动机构，连接转向器和车轮上的部件。车轮和轮胎安装在转向节上。如图5-1所示，转向节的上下端可自由转动，这样车轮可从一侧转到另一侧。Whilethesteeringsystemmaylookcomplicated,itworksquitesimply.Whenadriver

39、drivesacarstraightdowntheroad,thesteeringgeariscentered.Thegearholdsthelinkagecenteredsothatthewheelsandtirespointstraightahead.Whenthedriverturnsthesteeringwheel,thesteeringshaftrotatesandthesteeringgearmovestowardthatside.Theshaftcomingoutthebottomofthesteeringgearturns,aswell.Whentheshaftturns,it

40、pullsthelinkagetoonesideandmakesthesteeringknucklesturnslightlyabouttheirpivotpoints.Thus,thesteeringknuckle,spindle,wheels,andtiresturntooneside,causingthecartoturn.转向系看起来复杂，工作原理却很简单。汽车直行时，转向器处于中间位置，转向传动机构也处于中间位置，车轮直行。驾驶员转动方向盘，转向轴旋转，转向器向同侧转动，同时转向器底部的输出轴也会旋转。输出轴转动时，会向一侧拉动拉杆，使得转向节绕其支点旋转。这样，转向节、转向节轴端、

41、车轮和轮胎都会向一侧旋转，汽车实现转向。Thesuspensioncoversthearrangementusedtoconnectthewheelstothebody.Thepurposeistopreventlargeshocks,causedbythewheelsstrikingbumpsintheroad,beingpassedtothevehicleoccupantsandcomponents;otherwisediscomfortanddamagewouldoccur.5.6悬架是车架（车身）与车桥（车轮）之间一切连接传力装置的总称。其目的是防止车轮遇到路面不平产生的巨大冲击传给车

42、内的货物和乘客；否则会产生不舒适的感觉和货物的损坏Thesuspensionsystemhastwosubsystemsthefrontsuspensionandtherearsuspension.悬架系统有两个子系统一前悬架和后悬架hesuspensionsystemhastwosubsystemsthefrontsuspensionandtherearsuspension.Thefrontsuspensionismorecomplicatedthantherearsuspension.Thisisbecausethefrontwheelsmustmoveinseveraldifferentdir