汽车专业英语-6 Exhaust system

Chapter6EXHAUSTSYSTEM

背景知识汽车的排气系统功能主要是排放汽车尾气。构造上细分为尾气管（TheTailpipe）消音器（TheMuffler）排气歧管（TheExhaustManifoldandHeader）集气管（ManifoldtoExhaustPipeGaskets）排气管（ExhaustPipeHangers）这几大主要部件。。

Chapter6EXHAUSTSYSTEM

Theexhaustsystemcarriesexhaustgasesfromtheengine’scombustionchambertotheatmosphereandreduces,ormuffles,enginenoise.Exhaustgasesleavetheengineinapipe,travelingthroughacatalyticconverterandamufflerbeforeexitingthroughthetailpipe.译文：排气系统将来自发动机燃烧室的废气排放到空气中去，并减小或消除发动机噪音。废气从发动机排出，经过排气管道通过催化转换器和消声器，最后通过尾管排到大气中去。Chapter6EXHAUSTSYSTEM1.TheTailpipeThetailpipeisalongmetaltubeattachedtothemuffler.Itsticksoutfromunderthebodyofacar,attherear,inordertodischargetheexhaustgasesfromthemuffleroftheengineintotheairoutsidethecar.译文：尾管是与消声器相连的长长的金属管，它从汽车车身后部伸出，将来自发动机消声器的废气排到汽车以外的大气中去。Chapter6EXHAUSTSYSTEM2.TheMufflerExhaustgasesleavetheengineunderextremelyhighpressure.Ifthesegasesescapeddirectlyfromtheengine,thenoisewouldbetremendous.Forthisreason,theexhaustmanifoldsendsthegasestoamufflerwheretheygothroughmetalplates,ortubes,withaseriesofholes.Thepressureofthegasesisreducedwhentheypassthroughthemuffler,sotheygooutofthetailpipequietly.译文：废气在高压下离开发动机。如果这些废气直接从发动机排出，将会产生巨大的噪音。因此，排气歧管将废气送到消声器，废气通过有着许多孔洞的金属盘或管道。当废气通过消声器，压力被减小，这样废气就可以安静地排出尾管。Chapter6EXHAUSTSYSTEM2.TheMufflerThemufflerismadeofmetalandislocatedunderneaththebodyofacar.It’sconnectedbetweenthetailpipeandthecatalyticconverter.译文：消声器由金属做成，位于汽车车身下面。它与尾管和催化转换器相连。Chapter6EXHAUSTSYSTEMTherearetwotypesofmufflerdesign.Onetypeusesseveralbaffledchamberstoreducenoise.Theothertypesendsthegasesstraightthroughperforatedpipewrappedinmetalorfiberglass.Thistypeofmufflerisdesignedforthepurposeofreducingbackpressureand,consequently,makesslightlymorenoise.译文：有两种形式的消音器设计。一种是采用一些挡板隔腔来减小噪音，另一种是将噪音直接送到由金属或玻璃纤维包裹的多孔管道中。这种消音器的设计是用来减小背压，从而减小噪音。Chapter6EXHAUSTSYSTEMThemufflerquietsthenoiseoftheexhaustbymufflingthesoundwavescreatedbytheopeningandclosingoftheexhaustvalve.Whenanexhaustvalveopens,itdischargestheburnedgasesathighpressuresintotheexhaustpipe,whichisatlowpressure.Thistypeofactioncreatessoundwavesthattravelthroughtheflowinggas,movingmuchfasterthanthegasitself(upto1400mph)thatthemufflermustsilence.译文：消声器通过消除打开和关闭排气门产生的噪音来减小排气噪音。当排气门打开，它排出高压的燃烧气体至低压的排气管。这个动作产生声波，在废气中传播，并且速度要比废气本身速度更快（达到1400英里每小时）。这个噪音是消音器必须要消除的。Chapter6EXHAUSTSYSTEMItgenerallydoesthisbyconvertingthesoundwaveenergyintoheatbypassingtheexhaustgasandthroughperforatedchambersofvariedsize.Passingintotheperforationsandreflectorswithinthechamberforcesthesoundwavestodissipatetheirenergy.译文：消音器一般将废气通过不同尺寸的多孔腔室，从而将声波能转换为热能。废气通过腔室的孔洞及其在腔室内的反射可以消耗声波的能量。Chapter6EXHAUSTSYSTEMCarmanufacturersareexperimentingwithanelectronicmuffler,whichusessensorstomonitorthesoundwavesoftheexhaustnoise.Thesoundwavedataaresenttoacomputerthatcontrolsspeakernearthetailpipe.Thesystemgeneratessoundwave180degreesoutofphasewiththeenginenoise.译文：汽车生产商正在实验一种电子消声器，它使用传感器来检测排气噪音声波。声波信号被送到计算机，控制尾管附近的扬声器来产生一个与发动机噪音180度反相的声音。Chapter6EXHAUSTSYSTEMThesoundwavesfromtheelectronicmufflercollidewiththeexhaustsoundwavesandtheycanceleachotherout,leavingonlylow-levelheattoemergeformthetailpipe.译文：来自电子消声器的声波与排气噪音声波相撞，互相抵消，只将较少的能量由尾管排出。Chapter6EXHAUSTSYSTEM3.TheExhaustManifoldandHeaderTheexhaustmanifold,usuallyconstructedofcastiron,isapipethatconductstheexhaustgasesfromthecombustionchamberstotheexhaustpipe.Ithassmoothcurvesinitforimprovingtheflowofexhaust.

译文：排气歧管一般由铸铁做成，将废气由燃烧室送到排气管。排气歧管内有着光滑的表面，这是为了提高废气的流动。Chapter6EXHAUSTSYSTEM3.TheExhaustManifoldandHeaderTheexhaustmanifoldisboltedtothecylinderhead,andhasentrancesfortheairthatisinjectedintoit.Itisusuallylocatedundertheintakemanifold.Aheaderisadifferenttypeofmanifold,itismadeofseparateequal-lengthtubes.译文：排气歧管使用螺栓连接在气缸盖上，有着供空气喷入的通道。它同样位于进气歧管的下面。集气管是另一种形式的歧管，它由许多独立等长的管道组成。Chapter6EXHAUSTSYSTEM4.ManifoldtoExhaustPipeGasketsThereareseveraltypesofgasketsthatconnectstheexhaustpipetothemanifold.Oneisaflatsurfacegasket.Anothertypeusesaballandsocketwithspringstomaintainpressure.Thistypeallowssomeflexibilitywithoutbreakageofthesealorthemanifold.Athirdtypeisthefullballconnectortype,whichalsoallowsalittleflexibility.译文：有几种类型连接排气管和歧管的垫圈。一种是平面垫圈。另一种使用球铰式垫圈，使用弹簧来保持压力，它可以在不破坏密封和歧管的条件下允许产生一定的变形。第三种是全球式接头垫圈，它也允许产生少量的变形。Chapter6EXHAUSTSYSTEM5.ExhaustPipeHangersHangersholdtheexhaustsysteminplace.Theygivethesystemflexibilityandreducethenoiselevel.Thehangersystemconsistsofrubberrings,tubesandclamps.译文：排气管吊耳将排气系统固定住，并且使得排气系统有一定的灵活性和减小噪音级别。吊耳系统由橡胶圈，管子和夹具组成。Chapter6EXHAUSTSYSTEM6.ExhaustPipeTheexhaustpipeisthebent-uporconvolutedpipesunderneathacar.Someareshapedtogoovertherearaxle,allowingtherearaxletomoveupanddownwithoutbumpingintotheexhaustpipe,someareshapedtobendaroundunderthefloorofthecar,connectingthecatalyticconverterwiththemuffler.译文：排气管弯曲盘旋于汽车底部。一些排气管布置在后轴上，这样后轴上下跳动就不会撞击到排气管，一些盘旋弯曲于汽车底盘上，连接催化转换器和消声器。Chapter6EXHAUSTSYSTEM6.ExhaustPipeExhaustpipesareusuallymadeoutofstainlesssteel,sincethehighheatconditionsinvolvedwiththemufflersystemwillcauserust.译文：由于消声器的高温环境容易产生锈，所以排气管一般采用不锈钢做成。Chapter6EXHAUSTSYSTEM7.DualExhaustSystemTheadvantageofadualexhaustsystemisthattheengineexhaustsmorefreely,therebyloweringthebackpressure,whichisinherentinanexhaustsystem.Withadualsystem,asizableincreaseinenginehorsepowercanbeobtainedbecausethebreathingcapacityoftheengineisimproved,leavinglessexhaustgasesintheenginesattheendofeachexhauststroke.This,inturn,leavesmoreroomforanextraintakeoftheair-fuelmixture.译文：双排气系统的优势就是发动机能够更自由地排气，因此可以降低排气系统固有的背压。装有双排气系统的发动机可以获得相当大的功率提升，这是因为发动机进气的能力得到了改善。每次排气冲程末端，更少的废气被留在发动机内，从而给发动机吸入可燃混和气留下更多的空间。Chapter6EXHAUSTSYSTEMExercise1Carbonmonoxide(CO)alsoincreasestherateatwhichthephotochemicalsmogisformedbyspeedinguptheconversionofnitricoxide(NO)tonitrogendioxide.一氧化碳也增加了光化学烟雾形成的几率。因为一氧化碳促进了一氧化氮向二氧化氮的转变。2Oxideofsulfurwereinitiallyignoredintheexhaustsystem,sincethesulfurcontentofgasolineasafuelislessthan1/10of1percent.Becauseofthissmallamount,itwasfeltthatitcontributedverylittletotheoverallpollutionproblem.However,theautomobileexhaustsystem,whenequippedwithacatalyticconverter,changesthesulfurdioxideintosulfurtri