汽车工程专业英语翻译(部分)(正规版)

1、汽车工程专业英语翻译（部分）（正规版）Chapter1AutomotiveBasicsTodaysaveragecarcontainsmorethan15,000separate,individualpartsthatmustworktogether.Thesepartscanbegroupedintofourmajorcategories:body,engine,chassisandelectricalequipment。P1当今的车辆一般都由15000多个分散、独立且相互配合的零部件组成。这些零部件主要分为四类：车身、发动机、底盘和电气设备。BodyThebodyisdesignedtok

2、eeppassengerssafeandcomfortable.Thebodystylingprovidesanattractive,colorful,modernappearanceforthevehicle.P2车身的设计要保证乘客平安舒适。车身的款式使得汽车看起来漂亮迷人、色彩斑斓、时尚前卫。EngineTheinternalcombustionengineismostcommon:thisobtainsitspowerbyburningaliquidfuelinsidetheenginecylinder.Therearetwotypesofengine:gasolineanddiese

3、l.Bothenginesarecalledheatengines;theburningfuelgeneratesheatwhichcausesthegasinsidethecylindertoincreaseitspressureandsupplypowertorotateashaftconnectedtothetransmission.P3内燃机是最常见的，其动力来自气缸里液体燃料的燃烧。发动机有汽油机和柴油机两种，都称为热机燃料燃烧产生热量，使得气缸内气体压力升高，从而提供动力，带动连接变速器的轴旋转.ChassisSuspensionThepurposeofthecompletesus

4、pensionsystemistoisolatethevehiclebodyfromroadshocksandvibrations,whichwillotherwisebetransferredtothepassengersandload.Itmustalsokeepthetiresincontactwiththeroadregardlessofroadsurface.P5整个悬架系统的作用是隔离来自路的冲击和振动对车身的影响,防止它们传递给乘客和货物。另外不管路面如何,悬架系统都应该保持轮胎和路的接触。BrakingDrumbrakeshaveadrumattachedtothewheelh

5、ub,andbrakingoccursbymeansofbrakeshoesexpandingagainsttheinsideofthedrum.Withdiscbrakes,adiscattachedtothewheelhubisclenchedbetweentwobrakepads.P6在鼓式制动器上，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。1.4ElectricalsystemTheelectricalsystemsupplieselectricityforthestarter,ignition,lightsan

6、dheater.Theelectricitylevelismaintainedbyachargingcircuit.P8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。AutomotiveEngineeringEnglishChapter2InternalCombustionEngine2。1。2EngineTermsLinkingthepistonbyaconnectingrodtoacrankshaftcausesthegastorotatetheshaftthroughhalfaturn.Thepowerstrokeusesupthegas,someansm

7、ustbeprovidedtoexpeltheburntgasandrechargethecylinderwithafreshpetrol-airmixture:thiscontrolofgasmovementisthedutyofthevalves;(Page10)活塞通过连杆和轴连接，使得气体带动轴旋转半圈。作功冲程耗尽了所有的气体，这样就必须采取相应的措施排出废气以及向气缸内再充入新鲜的可燃混合气：气体的运动由气门来控。EngineBlockTheengineblockisthebasicframeoftheengine.Allotherenginepartseitherfitinsid

8、eitorfastentoit.Itholdsthecylinders,waterjackets,andoilgalleries.Theengineblockalsoholdsthecrankshaft,whichfastenstothebottomoftheblock.(Page13)缸体是发动机的基体。发动机其它的部件都安装或固定在缸体上，包括气缸、水套和油道，以及固定在缸体底部的曲轴等。CylinderSleevesCylindersleevesareusedinengineblockstoprovideahardwearingmaterialforpistonsandpistonrin

9、gs.Theblockcanbemadeofonekindofironthatislightandeasytocastwhilethesleevesusesanotherthatisbetterabletostandupwearandtear.Therearetwomaintypesofsleeves:dryandwet.(Page10)缸体中的气缸套为活塞和活塞环提供了一种坚硬耐磨的材料。缸体可以采用某种重量轻且易铸造的铁来制造，而缸套使用的却是另一种更加耐磨损的材料成。主要有两种类型的气缸套：干缸套和湿缸套。CylinderHeadThecylinderheadfastenstotheto

10、poftheblock,justasarooffitsoverahouse.Theundersideformsthecombustionchamberwiththetopofthepiston.In-lineenginesoflightvehicleshavejustonecylinderheadforallcylinders;largerin-lineenginescanhavetwoormore.(Page14)气缸盖安装在缸体的顶部，就像安在房子上的屋顶一样。缸盖的下方和活塞顶部形成燃烧室。轻型车上使用的直列发动机，所有气缸仅有一个气缸盖，较大的直列发动机有两个或更多缸盖。OilPanT

11、heoilpumpinthelubricatingsystemdrawsoilfromtheoilpanandsendsittoallworkingpartsintheengine.Theoildrainsoffandrunsdownintothepan.Thus,thereisconstantcirculationofoilbetweenthepanandtheworkingpatsoftheengine.(Page15)润滑系的机油泵从油底壳抽出机油并把机油输送给发动机的所有工作部件。机油从油底壳流进流出.因而在油底壳和发动机的工作部件之间就有机油定向循环流动。PistonAssembly

12、(Page17)Mostpistonsaremadefromcastaluminum.Thepiston,throughtheconnectingrod,transferstothecrankshafttheforcecreatedbytheburningfuelmixture.Thisforceturnsthecrankshaft.大多数活塞由铝铸造而成。通过连杆的作用，活塞把可燃混合气燃烧产生的力传递给曲轴，带动曲轴旋转。PistonIndieselengines,thecombustionchambermaybeformedtotallyorinpartinthepistoncrown,

13、dependingonmethodofinjection.(Page18)柴油机发动机根据喷油方法不同，活塞头部可以形成全部燃烧室，也可以是燃烧室的一局部PistonRingsInmodernengines,eachpistonhasthreerings.(PistoninolderenginesGasRingssometimeshadfourrings,orevenfive.)Theinsidesurfaceoftheringfitsinthegrooveonthepiston.Theringsoutsidesurfacepressesagainstthecylinderwalls.在新型发

14、动机上，每个活塞有三个活塞环。在老式发动机上，每个活塞有四个甚至五个活塞环环的内侧装在活塞的环槽里，环的外外表紧压在气缸壁上。ConnectingrodTheconnectingrodlittleendisconnectedtothepistonpin.Abushmadefromasoftmetal,suchasbronze,isusedforthisjoint.Thelowerendoftheconnectingrodfitthecrankshaftjournal.Thisiscalledthebigend.(Page19)连杆小头与活塞销连接，连接处有像青铜这样软金属制成的衬套，连杆下端连

15、接在曲柄轴径上，称为连杆大头。N.B.No.4pistonisalwaysperformingthecompanionstroketoNo.1:whentheinletvalveinNo.4cylinderisfullyopen,No.1cylinderinletvalveisfullyclosedthisfeatureisusefultorememberwhencheckingvalveclearances.(Page20)注意4号活塞和1号活塞总是成对运行：1号气缸进气门全闭时，4号气缸进气门全开这个特点在检查气门间隙时是很有用的。Aseachcylinderfires,itcausest

16、hecrankthrowtospeedup.Theinertiaoftherestofshaftcauseittostayslightlybehind,resultinginatwistingactiononthecrankshaft.(Page20)当一气缸点火时，使拐的转速提高，而轴的其它局部由于惯性作用，有所滞后,从而导致曲轴扭转。2.5:valvesystem1、Thecamisanegg-shapedpieceofmetalonashaftthatrotatesincoordinationwiththecrankshaft.Themetalshaft,calledthecamshaf

17、t,typicallyhasindividualcamsforeachvalveintheengine.Asthecamshaftrotates,thelobe,orhighspotofthecam,pushesagainstpartsconnectedtothestemofthevalve.Thisactionforcesthevalvetomovedownward.Thisactioncouldopenaninletvalveforanintakestroke,oropenanexhaustvalveforanexhauststroke.p26凸轮是一个蛋形的金属块，它安装在同曲轴协调运转

18、的一根轴上，该轴称为轮轴，其上有同发动机每一个气门对应的凸轮。当轮轴旋转时，轮的最高点，也就是凸圆，推动连接气门杆的部件，使得气门向下运动，在进气冲程翻开进气门，在排气冲程翻开排气门。2、Inthisarrangement,thecamlobespushagainstroundmetalcylinderscalledcamfollower.Asthelobeofthecamcomesupunderthecamfollower,itpushesthecamfollowerupward(awayfromthecamshaft).Thecamfollowerridesagainstapushrod,

19、whichpushesagainstarockerarm.Therockerarmpivotsonashaftthroughitscenter.Asonesideoftherockerarmmovesup,theothersidemovesdown,justlikeaseesaw.Thedownward-movingsideoftherockerarmpushesonthevalvestemtoopenthevalve.p27在这种方案中，轮圆推动圆形的金属筒，也就是挺柱。轮圆运动到挺柱下方时，推动挺柱远离轮轴向上运动。挺柱带着推杆，推杆推动摇臂，摇臂绕摇臂轴的中心转动。摇臂的一端升起，另一端

20、就落下，这类似于跷跷板。摇臂向下运动的一端推动气门杆翻开气门。3、Whentheenginerunsincompressionstrokeandpowerstroke,thevalvesmustclosetightlyontheirseatstoproduceagas-tightsealandthuspreventthegasesescapingfromthecombustionchamber.Ifthevalvesdonotclosefullytheenginewillnotdevelopfullpower.Alsothevalveheadswillbeliabletobeburntbyth

21、epassinghotgases,andthereisthelikelihoodofthepistoncrowntouchinganopenvalve,whichcanseriouslydamagetheengine.p28当发动机在压缩冲程和作功冲程作时，气门必须紧贴在气门座上，形成良好的气密性以防止燃烧室漏气。如果气门关闭不严，发动机就不能发挥出全部的功率。而且气门头部容易被经过的高温气体烧蚀，活塞顶部也可能会碰到气门使发动机严重损坏。4、Sothatthevalvescanclosefullysomeclearanceisneededintheoperatingmechanism.Thi

22、smeansthattheoperatingmechanismmustbeabletomovesufficientlyfarenoughawayfromthevalvetoallowthevalvestobefullyclosedagainstitsseatbythevalvespring.However,iftheclearanceissettoogreatthiswillcausealightmetallictappingnoise.p28所以在气门传动机构中要预留一些间隙使气门得以完全关闭。这就是说，气门传动机构运动要与气门有一个充分远的距离，使得气门在气门弹簧作用下紧闭气门座。可是如果

23、间隙过大，会引起轻微的金属敲打声。5、Itisapparentfromthisdescriptionthattheexhaustvalvestaysopenforashortperiodoftimeduringwhichtheintakevalveisalsoopen.Inotherwords,theendoftheexhauststrokeandthebeginningoftheintakestokeoverlapforashortperiodoftime.Thisiscalledvalveoverlap.Valvetimingandvalveoverlapvaryondifferenten

24、gines.p28由上显而易见，排气门在进气门翻开的一小段时间内也翻开着。换句话说，排气冲程终了和进气冲程初期有一小段时间的重叠，这称为气门重叠。不同的发动机，其配气正时和气门重叠是不一样的。6、OpeningtheintakevalvebeforeTDCandclosingitafterBDCincreasesthefillofair-fuelmixtureinthecylinder.Openingtheintakevalveearlyhelpsovercomethestaticinertiaoftheair-fuelmixtureatthebeginningoftheintakestrok

25、e,whileleavingtheintakevalveopenafterBDCtakesadvantageofthekineticinertiaofthemovingair-fuelmixture.Thisincreasesvolumetricefficiency.p28在上止点前翻开进气门和在下止点后关闭进气门可增加气缸内可燃混气的进气量提前翻开进气门有助于克服进气冲程初期可燃混气的静惯性，同时在下止点后保持进气门翻开，可充分利用可燃混气运动时的惯性，这可增加容积效率。7、Theentirevalve-trainassemblycanbeviewedasaspring/masssystem

26、inwhichtheconversionfromstoredtoreeenergycausesforcedvibration.Valve-trainassemblieswithoverheadcamshaftscanberepresentedwithsufficientaccuracybya1-masssystem(consistingofthemovingmass,thevalve-trainassemblystiffnessandcorrespondingdamping).p29整个气门机构总成可看成一个弹簧-质量系统，其储存的能量转化为自由能量时会引起受迫振动。带有顶置凸轮轴的气门机构可

27、非常精确地用单质量系统来表示，由运动质量、气门机构的刚度和相应的阻尼组成。8、Eachcammustrevolveonceduringthefour-strokecycletoopenavalve.Acycle,remember,correspondswithtworevolutionsofthecrankshaft.Therefore,thecamshaftmustrevolveatexactlyhalfthespeedofthecrankshaft.Thisisaccomplishedwitha2:1gearratio.Agearconnectedtothecamshafthastwice

28、thenumberofteethasagearconnectedtothecrankshaft.p29在一个四冲程的循环里，每个凸轮转动一次来翻开一个气门。在一个循环里曲轴是转动两圈的。因此，凸轮轴必须以曲轴转速的一半旋转，这是由2:1的传动比来实现的。连接凸轮轴的齿轮齿数是连接曲轴的齿轮齿数的2倍。9、Anelectronicvalvecontrolsystemreplacesthemechanicalcamshaft,controllingeachvalvewithactuatorsforindependentvalvetiming.TheEVCsystemcontrolstheopeni

29、ngandclosingtimeandliftamountofeachintakeandexhaustvalvewithindependentactuatorsoneachvalve.Changingfromamechanicaldrivenvalveintoindependentlycontrolledactuatorvalveprovidesahugeamountofflexibilityinenginecontrolstrategy.p30电控气门控制系统代替了机械式的凸轮轴，用执行器控制每个气门独立的进、排气正时。EVC通过每个气门上的独立执行器控制进气门和排气门的开启、关闭时间以及升

30、程量。由机械式驱动气门到独立控制执行器气门的转变，极大的增加了发动机控制策略的灵活性。2.6GasolineFuelSystem(P.33)Gasolinemustvaporizeeasily.Thischaracteristic,calledvolatility,isimportant.However,itmustnotvaporizetooeasily,oritwillturntovaporinsidethefueltankorfuellines.Insidethefuelline,fuelvapormayblocktheflowofliquidgasoline.Thisiscalledv

31、aporlock.Vaporlockiscommoninfuellineswheretheinletsideofthepumpisexposedtohightemperatures.油应易于蒸发，这个重要的特性称为挥发性。但是汽油也不能挥发得过快，不然它会在油箱或油管里转变为蒸气。在油管中油蒸气会阻碍液态油的流动，这称为气阻。汽油泵的入口处易受高温，就经常出现气阻。(P.33)Increasingthepressureofthefuelmixtureinthecombustionchamberbeforeignitionhelpstoincreasethepowerofanengine.Thi

32、sisdonebycompressingthefuelmixturetoasmallervolume.Highercompressionratiosnotonlyboostpowerbutalsogivemoreefficientpower.Butasthecompressionratiogoesup,knockingtendencyincreases.在点火前增加燃烧室内可燃混合气的压力有助于提高发动机的功率，这是通过把可燃混合气压缩到一个极小的体积来实现的。高的压缩比不仅可以增加功率，而且会带来更多的有功率。但随着压缩比的增加，爆震的可能性也会增加。(P.34)Twoprimarystan

33、dardreferencefuels,normalheptaneandiso-octanearbitrarilyassigned0and100octanenumber,respectively,arethenblendedtoproducethesameknockintensityasthetestsample.Thepercentageofiso-octaneinblendisconsideredtheoctanenumberofthetestsample.Thus,ifthematchingreferenceblendismadeupof15%n-heptaneand85%isooctan

34、e,thetestsampleisrated85motororresearchoctanenumber,accordingtothetestmethodused.两种标准参考燃料正庚烷和异辛烷分别被定义成辛烷值为0和辛烷值为100，将它们混合产生与实验样本相等敲缸强度的爆震。混合物中异辛烷的百分比就认为是实验样本的辛烷值。这样，依照实验方法，如果匹配的参考混合物由15%的正庚烷和85%异辛烷组成，那么按照所用的实验方法，比照实验样本的辛烷值就是85Fuelpump:Mostcarstodayhaveamechanicalfuelpump.Thispumpsfueloutofthetankand

35、throughthefuellinestothecarburetororinjectionsystem.Inmostcars,thepumpismountedontheengineblock.Somecarshaveanelectricfuelpump.Thispumpmountsinthefueltankwiththefuelpickupandthefuel-gauge-sendingunit.(P.37)当前大多数车采用机械油泵，油泵从油箱抽出油，通过油管送到化油器或喷射系统。大局部车的油泵安装在缸体上。一些车采用电动油泵，油泵安装在油箱上，附带有油量传感器和燃油表油量传送装置。Fuelp

36、ump:Therotationofthelobemovesarockerarminthepump.Insidethepump,aflexiblediaphragmconnectstotherockerarmthoughadiaphragmspring,pullrodandlink.(P.37)凸圆旋转带动油泵中的摇臂运动。油泵中可变形膜的泵膜通过膜回位弹簧和膜片拉杆与摇臂相连。(P.37)Acarburetordeliversfuelinproportiontotheamountofairflowingthroughit.Asyoupressontheacceleratorpedal,thet

37、hrottlevalveopenswidertodrawmoreairthroughthecarburetorThecarburetorprovidesricherorleanermixtures,dependingonanumberoffactors:enginespeed,load,temperature,andthrottleposition.Tomeetcomplicateddemands,acarburetorisahighlyintricatedevice,withmanyinternalpassagesandparts.化油器输送的燃油与流经化油器的空气量成一定比例。踩下加速踏板

38、，节气门开度变大，化油器吸入的空气增加。化油器可提供较浓或较稀的混合气，这取决于发动机转速、负荷、温度和油门开度等因素。为满足复杂的要求，化油器的结构也很复杂，其上有很多内部通道和部件。(P.37)Venturi:Anautomobilecarburetorisdesignedwithaventurichamber.Theventuriissimplyanarrowedportionintheairpassage.Airmovingthroughthethroatofthecarburetorspeedsupasittravelsthroughthisnarrowedpassageway.Th

39、eincreasedairspeedthroughtheventuricreatesalow-pressureareaattheopeningofthefuelnozzle.Atmosphericpressurepushesdownonafuelreservoirwithinthecarburetorknownasthefloatchamber.Fuelisforcedthroughatubethatextendsintothelow-pressureareaoftheventuri.Thus,fuelspraysthroughtheendofthetubeintotheairstream.化

40、油器设计成带有喉管的形式，喉管只是空气通道中一段狭窄的局部。空气流过化油器的喉管时速度增加，在喷嘴的开口处形成低压区。大气压力作用在储存汽油的浮子室上。燃油便被压入伸向喉管低压区的喷管里。这样燃油从喷管末端喷射到气流中。(P.38)carburetor:Thefloatchamberisareservoirforstoringandsupplyingfueltothecarburetor.Astheengineusesfuel,thefloatchamberreplenishesitautomaticaThlely.floatchamberworksonthesamebasicprincipl

41、eastheholdingtankinaflushingtoilet.Afloatrestsontopofthefuelinthereservoir.Asfuelisused,thefloatleveldrops.Whenthefloatdrops,aneedlevalveisopened.浮子室用于储存燃油以及向化油器提供燃油。发动机消耗燃油时，浮子室会自动进行补充。浮子室和抽水马桶储水箱的根本工作原理是相同的。浮子停留在浮子室的油面上。消耗燃油时，浮子下落，针阀翻开。(P.38)Thepressuredifferentialbetweenthefloatchamberandtheventu

42、ricausesfueltoflow.However,tomaintaintheproperair-fuelratio,thecarburetormustprovidejusttherightamountoffuel.Todoso,themaindischargetubehasasmallhole(calledajetormainjet).Thisallowsapreciseamountoffueltoentertheairstream.Inmostcases,thissmallholeisinthefloatchamberattheendofthemaindischargetube.Ther

43、e,itssmallsizelimitsfuelflow.浮子室和喉管之间的压力差引燃油的流动。然而，为维持适宜的空燃比，化油器必须提供适量的燃油。为此，在主喷管上有一个小孔，称作量孔或主量孔，它使得精确数量的燃油进入到气流中。量孔一般在主喷管末端的浮子室里，控制着燃油的流量。10(P.38)Thethrottlemechanismcontrolstheflowoftheair-fuelmixture.Thethrottlehasseveralparts,includingthethrottleshaftandthethrottleplate.Byopeningandclosing,theth

44、rottleplatecontrolstheflowoftheair-fuelmixtureintotheengine.Moreairflowsinastheplateopens;lessairflowsinastheplatecloses.节气门机构控制着可燃混合气的流量，包括节气门轴和节气门等部件。节气门的开启和关闭控制着进入发动机的可燃混合气流量。节气门开启，空气流量增加；节气门关闭，空气流量减少。GasolinedirectinjectionGDIConventionalgasolineenginesaredesignedtouseanelectronicfuelinjectionsy

45、stem,replacingthetraditionalmechanicalcarburetionsystem.Multi-pointinjection(MPI),wherethefuelisinjectedthrougheachintakeport,iscurrentlyoneofthemostwiderusedsystems.AlthoughMPIprovidesadrasticimprovementinresponseandcombustionquality,itisstilllimitedduetofuelandairmixingpriortoenteringcylinder.(p42

46、)常规的汽油发动机用电控燃油喷射系统代替传统的机械化油系统。通过每个进口喷射燃料的多点喷射MPI系统是现在最广泛使用的系统之一。尽管MPI系统在燃料反响及燃烧质量上有很大的改善，但是进入缸前的空燃混合气仍然限制了它的开展。2.7DieselEngine(P.46)DieselenginegetsthisnamefromthepioneerworkdonebyDrRudolfDiesel.Thedieselisusedforthemajorityofheavyvehiclesandtheexcellentfueleconomymakesitanattractivealternativetothe

47、petrolengineforlightcommercialvehicles,deliveryvansandtaxis.柴油发动机的名称来源于RudolfDiesel博士所完成的开拓性工作。大多数重型车辆使用柴油，优良的燃油经济性使得柴油机成为具有吸引力的替代品,来代替轻型商用车、厢式运输货车和出租车上汽油机。(P.48)Asdieselenginesalwaysdealwithinteriormixtureformationonlyaheterogeneousmixtureisobtainedinthecombustionchamber.Inheterogeneousmixturesthee

48、xcess-airfactor久extendsfrompureairinthesprayperiphery(l=infinite)topurefuelinthespraycore(l=由于油机总是只在气缸内部形成可燃混合气，在燃烧室内就会得到不均匀的混合气。不均匀混合气的过量空气系数范围从喷射外围纯空气的无穷大到喷射中心纯燃的零。(P48)Thefuel-injectionsystemonadieselenginemustdoanumberofimportantthings.First,itmustmeterthecorrectamountoffueltoruntheengineatthesp

49、eedandloaddemandedbythedriver.Thenitmustdeliverthemeteredfuelequallytoallcylinders,atexactlytherighttime.Next,itmustinjectthefuelatthecorrectrateandspraypatternforthebestburninginthecombustionchamber.(P48)柴油机的燃油喷射系统要完成许多重要的工作。首先，它必须定量供给准确数量的燃油，使发动机在驾驶员所要求的转速和负荷条件下运行。然后，它必须准确地在恰当的时刻把定量供给的燃油平均分配给每一个气缸

50、。为使燃烧室中燃燃烧效果最好，它又必须以准确的速度和喷射方式喷油。Withtheinjectorpumponthelowpart(basecircle)ofthecamshaft,theinletandspillportsareopen.Thisallowsfueltoflowat268kPaintotheventuriontopoftheplunger.Asthecamshaftturns,thelobemovestheplungerupward.Thisraisedthefuelpressure,forcingfuelthroughthedeliveryvalveandonthrought

51、helines.Thelobecontinuestomovetheplungerupwardtoapointwherethespiralgrooveintheplungeruncoversthespillportintheventuri.Atthispoint,fuelabovetheplungerdrainsthroughthespillport.Thisistheendofinjection.(P.49)当喷油泵处于凸轮轴基圆时，进油孔和回油孔都翻开，柴油以268KPa的压力流入柱塞上方的柱塞腔。凸轮轴旋转时,凸圆使柱塞向上移动,油压增加，油从出油阀流出送入高压油管。凸圆继续推动柱塞向上移

52、动，直到柱塞运动到螺旋槽翻开柱塞腔上的回油孔时的位置，此时，柱塞上方的柴油从回油孔流出，喷油过程结束。Atequilibrium,thecontrolrodassumesapositionforasupplyoffuelwhichcorrespondstoenginepowerat,thatoperatingpoint.Ifenginespeeddropsasaresultofincreasedload,forexample,thecentrifugalforceisalsoreducedandthegovernorspringsmovetheflyweights,andthusthecont

53、rolrod,inthedirectionofincreasedfueldeliveryuntilequilibriumisagainestablished.(p52)平衡时，控制杆的供油位置由该工况点发动机相应功率决定例如，如果由于负载增加，发动机速度下降，飞块的离心力会随之下降此时，调速器弹簧压动飞块，带动控制杆向加油方向运动直至平衡重新建立6)(P52)Allpreviousinjectionsystemshaveonedisadvantageincommon:thepressuregenerationandthesupplyoftheinjectionquantityarenotmut

54、uallyindependent.Theresultisthattheinjectionpressureincreaseswiththeenginespeedandalsoincreasesduringinjection(approximatelylinearly).Consequently,smallerinjectionquantitiesareinjectedwithlowpressure.Thepeakpressureisalmosttwiceashighastheaverageinjectionpressure,whichisresponsibleforthequalityofthe

55、fuelswirlinthecombustionchamber.前述所有的喷射系统都有一个共同的缺点：油压的产生和喷射的供油量不是相互独立的，这样喷油压力随转速而增加，同样在喷油期间也几乎呈线性增加。因此，少量柴油会以低压喷射。最高喷油压力几乎是平均喷油压力的两倍，这会影响燃烧室内柴油漩涡的质量(P53)Apressureaccumulatorissuppliedwithfuelbyahigh-pressurepump(CommonRail).Thepressureinthecommonrailismeasuredwithapressuresensorandsettledtoaconstant

56、valuebyapressure-controlvalveinthehigh-pressurepump.Dependingontherequirementsofcombustion,thepressureintherailcanbemaintained,largelyindependentoftheenginespeed,ataconstantvalueintherangebetween15140MPa.高压油泵共轨管向积压器供油。压力传感器测量共轨管的压力，高压油泵的油压控阀将压力控为一个常数。根据燃烧的要求，共轨管内的油压维持在15140MPa范围内的一个固定值，这根本上与发动机转速无关。

57、(P54)Atexhaust-gasturbo-charging,theexhaust-gasenergywhichwouldhavebeenlostisusedtodriveaturbine.Thisturbinedrivesacompressorwhichaspiratesthecombustionairandsuppliesitpre-compressedtotheengine.Inthisway,morefuelcanbesuppliedtothelargerairmassandtheenginepowerisincreased.Apositiveeffectisalsoexerted

58、onthecombustionprocess.在废气涡轮增压中，原本要丧失的废气能量用来驱动涡轮，涡轮驱动压缩机，压缩机吸入助燃空气，预压缩后送给发动机。这样，空气量多，供油也多，发动机功率就会增加，对燃烧过程也会带来积极作用。2.8EmissionControlThermostatcirculation(P58)Whentheengineiscool,thethermostatremainsclosedsothatcoolantcannotcirculatethroughtheradiator.Instead,coolantisrecirculatedwithintheengineblock

59、andcylinderheaduntilthecoolantreachesapredeterminedtemperature.Atthattemperatureawax-likepelletexpandsinsidethethermostattoopenitandallowthecoolanttoflow.Today,mostoriginal-equipmentthermostatsopenatapproximately85oCto90oC.Inhotterclimates,a“coolerthermostatmaybeusedtohelpavoidoverheating.当发动机温度较低时，

60、节温器保持关闭，冷却水不能流通散热器进行循环，而是在发动机缸体和缸盖之间循环流动，一直到冷却水到达预定的温度为止。在该温度下，节温器中的蜡芯膨胀，从而翻开节温器，使得循环水流经节温器。目前，多数原装节温器的开启温度大约在8590oC。气温较高时，可采用低温节温器防止发动机过热。anti-freeze:Thisisasolutionwhichisaddedtothecoolingsystemtolowerthetemperatureatwhichfreezingofthecoolantoccurs:theactualfreezingtemperatureisgovernedbythequanti