汽車專業(yè)英語-6 Exhaust system

Chapter6EXHAUSTSYSTEM

背景知識汽車的排氣系統(tǒng)功能主要是排放汽車尾氣。構(gòu)造上細分為尾氣管（TheTailpipe）消音器（TheMuffler）排氣歧管（TheExhaustManifoldandHeader）集氣管（ManifoldtoExhaustPipeGaskets）排氣管（ExhaustPipeHangers）這幾大主要部件。。

Chapter6EXHAUSTSYSTEM

Theexhaustsystemcarriesexhaustgasesfromtheengine’scombustionchambertotheatmosphereandreduces,ormuffles,enginenoise.Exhaustgasesleavetheengineinapipe,travelingthroughacatalyticconverterandamufflerbeforeexitingthroughthetailpipe.譯文：排氣系統(tǒng)將來自發(fā)動機燃燒室的廢氣排放到空氣中去，并減小或消除發(fā)動機噪音。廢氣從發(fā)動機排出，經(jīng)過排氣管道通過催化轉(zhuǎn)換器和消聲器，最后通過尾管排到大氣中去。Chapter6EXHAUSTSYSTEM1.TheTailpipeThetailpipeisalongmetaltubeattachedtothemuffler.Itsticksoutfromunderthebodyofacar,attherear,inordertodischargetheexhaustgasesfromthemuffleroftheengineintotheairoutsidethecar.譯文：尾管是與消聲器相連的長長的金屬管，它從汽車車身后部伸出，將來自發(fā)動機消聲器的廢氣排到汽車以外的大氣中去。Chapter6EXHAUSTSYSTEM2.TheMufflerExhaustgasesleavetheengineunderextremelyhighpressure.Ifthesegasesescapeddirectlyfromtheengine,thenoisewouldbetremendous.Forthisreason,theexhaustmanifoldsendsthegasestoamufflerwheretheygothroughmetalplates,ortubes,withaseriesofholes.Thepressureofthegasesisreducedwhentheypassthroughthemuffler,sotheygooutofthetailpipequietly.譯文：廢氣在高壓下離開發(fā)動機。如果這些廢氣直接從發(fā)動機排出，將會產(chǎn)生巨大的噪音。因此，排氣歧管將廢氣送到消聲器，廢氣通過有著許多孔洞的金屬盤或管道。當廢氣通過消聲器，壓力被減小，這樣廢氣就可以安靜地排出尾管。Chapter6EXHAUSTSYSTEM2.TheMufflerThemufflerismadeofmetalandislocatedunderneaththebodyofacar.It’sconnectedbetweenthetailpipeandthecatalyticconverter.譯文：消聲器由金屬做成，位于汽車車身下面。它與尾管和催化轉(zhuǎn)換器相連。Chapter6EXHAUSTSYSTEMTherearetwotypesofmufflerdesign.Onetypeusesseveralbaffledchamberstoreducenoise.Theothertypesendsthegasesstraightthroughperforatedpipewrappedinmetalorfiberglass.Thistypeofmufflerisdesignedforthepurposeofreducingbackpressureand,consequently,makesslightlymorenoise.譯文：有兩種形式的消音器設(shè)計。一種是采用一些擋板隔腔來減小噪音，另一種是將噪音直接送到由金屬或玻璃纖維包裹的多孔管道中。這種消音器的設(shè)計是用來減小背壓，從而減小噪音。Chapter6EXHAUSTSYSTEMThemufflerquietsthenoiseoftheexhaustbymufflingthesoundwavescreatedbytheopeningandclosingoftheexhaustvalve.Whenanexhaustvalveopens,itdischargestheburnedgasesathighpressuresintotheexhaustpipe,whichisatlowpressure.Thistypeofactioncreatessoundwavesthattravelthroughtheflowinggas,movingmuchfasterthanthegasitself(upto1400mph)thatthemufflermustsilence.譯文：消聲器通過消除打開和關(guān)閉排氣門產(chǎn)生的噪音來減小排氣噪音。當排氣門打開，它排出高壓的燃燒氣體至低壓的排氣管。這個動作產(chǎn)生聲波，在廢氣中傳播，并且速度要比廢氣本身速度更快（達到1400英里每小時）。這個噪音是消音器必須要消除的。Chapter6EXHAUSTSYSTEMItgenerallydoesthisbyconvertingthesoundwaveenergyintoheatbypassingtheexhaustgasandthroughperforatedchambersofvariedsize.Passingintotheperforationsandreflectorswithinthechamberforcesthesoundwavestodissipatetheirenergy.譯文：消音器一般將廢氣通過不同尺寸的多孔腔室，從而將聲波能轉(zhuǎn)換為熱能。廢氣通過腔室的孔洞及其在腔室內(nèi)的反射可以消耗聲波的能量。Chapter6EXHAUSTSYSTEMCarmanufacturersareexperimentingwithanelectronicmuffler,whichusessensorstomonitorthesoundwavesoftheexhaustnoise.Thesoundwavedataaresenttoacomputerthatcontrolsspeakernearthetailpipe.Thesystemgeneratessoundwave180degreesoutofphasewiththeenginenoise.譯文：汽車生產(chǎn)商正在實驗一種電子消聲器，它使用傳感器來檢測排氣噪音聲波。聲波信號被送到計算機，控制尾管附近的揚聲器來產(chǎn)生一個與發(fā)動機噪音180度反相的聲音。Chapter6EXHAUSTSYSTEMThesoundwavesfromtheelectronicmufflercollidewiththeexhaustsoundwavesandtheycanceleachotherout,leavingonlylow-levelheattoemergeformthetailpipe.譯文：來自電子消聲器的聲波與排氣噪音聲波相撞，互相抵消，只將較少的能量由尾管排出。Chapter6EXHAUSTSYSTEM3.TheExhaustManifoldandHeaderTheexhaustmanifold,usuallyconstructedofcastiron,isapipethatconductstheexhaustgasesfromthecombustionchamberstotheexhaustpipe.Ithassmoothcurvesinitforimprovingtheflowofexhaust.

譯文：排氣歧管一般由鑄鐵做成，將廢氣由燃燒室送到排氣管。排氣歧管內(nèi)有著光滑的表面，這是為了提高廢氣的流動。Chapter6EXHAUSTSYSTEM3.TheExhaustManifoldandHeaderTheexhaustmanifoldisboltedtothecylinderhead,andhasentrancesfortheairthatisinjectedintoit.Itisusuallylocatedundertheintakemanifold.Aheaderisadifferenttypeofmanifold,itismadeofseparateequal-lengthtubes.譯文：排氣歧管使用螺栓連接在氣缸蓋上，有著供空氣噴入的通道。它同樣位于進氣歧管的下面。集氣管是另一種形式的歧管，它由許多獨立等長的管道組成。Chapter6EXHAUSTSYSTEM4.ManifoldtoExhaustPipeGasketsThereareseveraltypesofgasketsthatconnectstheexhaustpipetothemanifold.Oneisaflatsurfacegasket.Anothertypeusesaballandsocketwithspringstomaintainpressure.Thistypeallowssomeflexibilitywithoutbreakageofthesealorthemanifold.Athirdtypeisthefullballconnectortype,whichalsoallowsalittleflexibility.譯文：有幾種類型連接排氣管和歧管的墊圈。一種是平面墊圈。另一種使用球鉸式墊圈，使用彈簧來保持壓力，它可以在不破壞密封和歧管的條件下允許產(chǎn)生一定的變形。第三種是全球式接頭墊圈，它也允許產(chǎn)生少量的變形。Chapter6EXHAUSTSYSTEM5.ExhaustPipeHangersHangersholdtheexhaustsysteminplace.Theygivethesystemflexibilityandreducethenoiselevel.Thehangersystemconsistsofrubberrings,tubesandclamps.譯文：排氣管吊耳將排氣系統(tǒng)固定住，并且使得排氣系統(tǒng)有一定的靈活性和減小噪音級別。吊耳系統(tǒng)由橡膠圈，管子和夾具組成。Chapter6EXHAUSTSYSTEM6.ExhaustPipeTheexhaustpipeisthebent-uporconvolutedpipesunderneathacar.Someareshapedtogoovertherearaxle,allowingtherearaxletomoveupanddownwithoutbumpingintotheexhaustpipe,someareshapedtobendaroundunderthefloorofthecar,connectingthecatalyticconverterwiththemuffler.譯文：排氣管彎曲盤旋于汽車底部。一些排氣管布置在后軸上，這樣后軸上下跳動就不會撞擊到排氣管，一些盤旋彎曲于汽車底盤上，連接催化轉(zhuǎn)換器和消聲器。Chapter6EXHAUSTSYSTEM6.ExhaustPipeExhaustpipesareusuallymadeoutofstainlesssteel,sincethehighheatconditionsinvolvedwiththemufflersystemwillcauserust.譯文：由于消聲器的高溫環(huán)境容易產(chǎn)生銹，所以排氣管一般采用不銹鋼做成。Chapter6EXHAUSTSYSTEM7.DualExhaustSystemTheadvantageofadualexhaustsystemisthattheengineexhaustsmorefreely,therebyloweringthebackpressure,whichisinherentinanexhaustsystem.Withadualsystem,asizableincreaseinenginehorsepowercanbeobtainedbecausethebreathingcapacityoftheengineisimproved,leavinglessexhaustgasesintheenginesattheendofeachexhauststroke.This,inturn,leavesmoreroomforanextraintakeoftheair-fuelmixture.譯文：雙排氣系統(tǒng)的優(yōu)勢就是發(fā)動機能夠更自由地排氣，因此可以降低排氣系統(tǒng)固有的背壓。裝有雙排氣系統(tǒng)的發(fā)動機可以獲得相當大的功率提升，這是因為發(fā)動機進氣的能力得到了改善。每次排氣沖程末端，更少的廢氣被留在發(fā)動機內(nèi)，從而給發(fā)動機吸入可燃混和氣留下更多的空間。Chapter6EXHAUSTSYSTEMExercise1Carbonmonoxide(CO)alsoincreasestherateatwhichthephotochemicalsmogisformedbyspeedinguptheconversionofnitricoxide(NO)tonitrogendioxide.一氧化碳也增加了光化學煙霧形成的幾率。因為一氧化碳促進了一氧化氮向二氧化氮的轉(zhuǎn)變。2Oxideofsulfurwereinitiallyignoredintheexhaustsystem,sincethesulfurcontentofgasolineasafuelislessthan1/10of1percent.Becauseofthissmallamount,itwasfeltthatitcontributedverylittletotheoverallpollutionproblem.However,theautomobileexhaustsystem,whenequippedwithacatalyticconverter,changesthesulfurdioxideintosulfurtri