汽車專業(yè)英語翻譯與課后答案-黃韶炯(全部單元都有)

Unit1AutomotiveBasicsAutomobiles,trucks,andbusesareessentialformsoftransportation.Theyarecomplexmachinesmadeupofmanyparts.Thesepartscanbegroupedintoanumberofsystems.Anunderstandingofhowthesystemworkwillhelpyouunderstandhowtheautomobileworks.轎車、卡車和客車是交通運輸?shù)闹匾M成部分。它們都是由許多部件組成的復(fù)雜機器。這些部件可以歸類為汽車的幾個組成系統(tǒng)。了解這些各個小系統(tǒng)是如何工作的將有助于我們理解整個汽車系統(tǒng)是如何工作。Anautomobilecanbedividedintotwobasicparts:abodyandachassis.Thebodyistheenclosurethathousestheengine,passengers,andcargo.Itisthepartoftheautomobilethatyousee.Thechassisisthatpartoftheautomobilebeneaththebody.汽車可以分為兩個基本部分：車身和底盤。車身包圍發(fā)動機、乘客和行李，它是汽車你所看到的部分。而車身以下的部分就是底盤。THEBODYAnautomobilebodyisasheetmetalshellwithwindows,doors,ahood,andatrunkdeckbuiltintoit.Itprovidesaprotectivecoveringfortheengine,passengers,andcargo.Thebodyisdesignedtokeeppassengerssafeandcomfortable.Forexample,insulationinthebodyreducesnoiseandprotectsagainstheatandcold.Thebodystylingprovidesanattractive,colorful,modernappearanceforthevehicle.Itisstreamlinedtolessenwindresistanceandtokeepthecarfromswayingatdrivingspeeds.轎車車身是一個鉞金件殼體，它上面有車窗、車門、發(fā)送機罩和行李艙門等部件，它給發(fā)動機、乘客和行李提供防護。車身設(shè)計來確保乘客乘坐的安全和舒適。比如：車身絕熱層可以減少噪音和抵御冷熱。車身造型設(shè)計使得汽車有一個華美、現(xiàn)代、吸引人的外觀。車身的流線型設(shè)計可以減少風(fēng)阻，防止汽車行馳過程中發(fā)生擺動。Theautomobilebodyhastwobasicparts-theupperbodyandtheunderbody.車身有兩個基本部分-車身上部和車身下部。ThechassisThechassisisanassemblyofthosesystemsthatarethemajoroperatingpartsofavehicle.Thechassisincludeseverythingexceptthebody.Thethreeimportantpartsofthechassisaretheframe,theengine,andthepowertrain(alsocalledthedrivetrain).Eachofthesethreepartsismadeupofanumberofsystems.Asystemisamechanicalorelectricalunitthatperformsaspecificfunction.Thus,eachsystem(suchassteering,brake,orfuel)hasacertainjobtodoinrunningavehicle.Weshalllookateachofthesepartsandsystemstoseehowtheyfittogethertoformtheautomobilechassis.底盤集中了汽車大部分的運動組件，它包括除了車身以外的所有部件。底盤有三個重要的系統(tǒng)：車架、發(fā)動機和傳動系統(tǒng)。這三個系統(tǒng)又都有許多個完成某一個特定功能的機械或電氣系統(tǒng)組成。為了保證汽車正常運轉(zhuǎn)，每個系統(tǒng)(比如：轉(zhuǎn)向、制動或燃油系統(tǒng))都要實現(xiàn)一定的功能。下來我們看看這些系統(tǒng)和組件是如何相互連接從而組成汽車底盤的。TheframeThefirstmajorpartofthechassisistheframe.Itismadefromtoughsteelsectionswelded,riveted,orboltedtogether.Theframelookslikeasteelladder,thoughitsometimehasanXshapeforextrastrength.Itformsafoundationforthecarbodyandthepartsoftheseveralsystems.Thebodyisjoinedtotheframewithbolts.Rubbershockmountsorwashersareusedateachjoint.Thesereducevibrationandroadnoise.Inmostmoderncarstheframeisbuiltintothebody.Acarwiththeframebuiltintothebodyhasaunitizedbodyorunibody.Theframesupportsthesuspensionsystem,steeringsystem,andthebrakingsystem.底盤最重要的部分就是車架。車架由鋼件通過焊接、挪接或螺栓聯(lián)接而成，看上去就像一架鋼梯。有時為了得到額外的強度，車架做成了 X形狀。車架為車身和很多系統(tǒng)部件提供了底座。車身和車架使用螺栓聯(lián)接。每個聯(lián)接使用橡膠防震支架或墊圈來減振降噪?，F(xiàn)代轎車車架和車身做在了一起。采用這個形式的汽車車身叫做承載式車身。車架支撐懸架、轉(zhuǎn)向和剎車系統(tǒng)。Thefrontandrearwheelsareattachedtothechassisbyasuspensionsystem.Thissystemismadeupofsprings,shockabsorbers,controlarms,andstabilizers.Thesesupportthevehicleandcushionitfromroadbumpsforbetterrideandhandling.前后輪通過懸架系統(tǒng)和底盤相連。懸架系統(tǒng)由彈簧、減振器、控制臂和橫向穩(wěn)定桿組成。它們支撐著車身，并減緩由于路面不平引起的顛簸，以獲得更好的乘坐舒適性和操作穩(wěn)定性。Thesteeringsystemcontrolsthecar 'sdirectionoftravel.Itincludesawheelandcolumn,steeringgears,rods,andlinkages.Asthesteeringwheelisturned,itsmotionistransferredtotheidlerarmandtierods.Thesecausethefrontwheelstoturntotherightofleft.Onsomecars,apowerunit(calledpowersteering)makessteeringeasier.轉(zhuǎn)向系統(tǒng)控制車輛行馳的方向。它包括方向盤、轉(zhuǎn)向管柱、轉(zhuǎn)向器、轉(zhuǎn)向拉桿和轉(zhuǎn)向傳動裝置。當(dāng)轉(zhuǎn)動方向盤，方向盤的運動被傳遞到隨動臂和橫拉桿，從而使得前輪向左或向右轉(zhuǎn)動。有些車輛使用助力轉(zhuǎn)向裝置，從而使得轉(zhuǎn)向更加輕便。Thebrakesystemgivestheautomobileitsstoppingpower.Hydraulicbrakesarefoundonallmoderncars.Asthebrakepedalispushedwiththefoot,brakefluidisforcedthroughbrakelinesintocylindersthatpressthebrakeshoesagainstadrum.Thisstopsthemotionofthecar.Powerunits(powerbrakes)areusedtomakebrakingeasier.Mostmoderncarshavediscbrakesonthefrontwheels.(Somehavethemonboththefrontandrearwheels.)Discbrakesworklikeapairofplierssqueezingarotatingdisc.Drumbrakesarealsoused.制動系統(tǒng)給車輛制動的動力。現(xiàn)代轎車都使用液壓制動。 當(dāng)踩下制動踏板，制動液通過制動管路流入制動缸，強迫制動蹄接觸制動鼓，從而阻止車輛運動。為了使剎車更加輕便，車輛也使用助力制動?，F(xiàn)代轎車在前輪裝備盤式制動器。(一些轎車在前后輪都使用盤式制動器。 )盤式制動器工作原理類似一對鉗子夾住旋轉(zhuǎn)的盤片。也有前后輪都使用鼓式制動器的汽車。TheengineTheengineprovidespowertomovetheautomobile.Themostcommontypeofautomobileengineisthegasoline-burningpistonengine.Itisfoundinmostautomobiles.Diesel-fuelburningenginesarealsousedinmodernpassengercars,aswellasinlargetrucks.Allengineshavefuel,exhaust,cooling,andlubricationsystems.Gasolineenginesalsohaveanignitionsystem.發(fā)動機給汽車提供動力。最常見的發(fā)動機是汽油機。大多數(shù)汽車都使用它。 現(xiàn)代客車和大型卡車使用柴油機。所有的發(fā)動機都具有燃油、排放、冷卻和潤滑系統(tǒng)。汽油發(fā)動機還有一套點火系統(tǒng)。Theignitionsystemsuppliestheelectricsparkneededtoignitetheair-fuelmixtureinthecylinders.Whentheignitionswitchisturnedon,currentflowsfromthe12-voltstoragebatterytotheignitioncoil.Thecoilbooststhevoltagetoproducethestrongsparkof20,000Vneededtoignitetheenginefuel.Thedistributordirectstheelectricalcurrenttotherightsparkplugattherighttime.Dieselenginesusetheheatcausedbyenginecompressiontoignitethefuelcharge.Theseenginesarecalledcompressionignitionengines.點火系統(tǒng)提供點燃氣缸內(nèi)油氣混和物的電火花。當(dāng)打開點火開關(guān)，電流從 12V電池流向點火線圈。點火線圈升高電壓，產(chǎn)生用于點火的20000V尖峰電壓。分電器引導(dǎo)電流在正確的時刻流向正確的火花塞。 柴油機使用壓縮發(fā)動機產(chǎn)生的熱量來點燃燃料，因此被稱為壓燃式發(fā)動機。Theautomobilesuppliesalltheelectricityitneedsthroughitselectricalsystem.Forexample,theelectricalsystemsupplieselectricityfortheignition,horn,lights,heater,andstarter.Theelectricitylevelismaintainedbyachargingcircuit.Thiscircuitconsistsofthebattery,alternator(orgenerator),andtheregulator.Thebatterystoreselectricity.Thealternatorchangestheengine'mechanicalenergyintoelectricalenergyandrechargethebattery.Theregulatorpreventsdamagetothesystembyregulatingthemaximumvoltageinthecircuit汽車通過自身的電氣系統(tǒng)給自身供電。比如：電氣系統(tǒng)給點火系統(tǒng)、喇叭、燈光、供暖系統(tǒng)和起動器供電。系統(tǒng)電壓通過充電系統(tǒng)保持穩(wěn)定。充電系統(tǒng)由電池、發(fā)電機和調(diào)節(jié)器組成。電池儲存電能。發(fā)電機將發(fā)動機的機械能轉(zhuǎn)變?yōu)殡娔?，并給電池充電。調(diào)節(jié)器調(diào)節(jié)電氣系統(tǒng)的最大電壓，提供過壓保護。Thefuelsystemstoresliquidfuelanddeliversittotheengines.Thefuelisstoredinthetank,whichisconnectedtoafuelpumpbyafuelline.Thefuelispumpedfromthefueltankthroughthefuellines.Itisforcedthroughafilter(whichremovesmoistureanddirt)intothecarburetor,whereitismixedwithair,orintothefuelinjectionsystem.Thefuelismixedwithairtoformacombustiblemixtureinthecarburetor,themanifold,orthecylindersthemselves.燃油系統(tǒng)儲存液態(tài)燃料，并且把燃料送至發(fā)動機。燃料儲存在通過油管與油泵連接的油箱里。油泵通過油管將油箱內(nèi)的油泵出，并通過濾清器(去除濕氣和雜污)送達化油器與空氣混合或者噴油系統(tǒng)。燃油在化油器、歧管或氣缸自身內(nèi)與空氣混合，形成可燃混和物。Theexhaustsystemhasfourjobs:Tocollectburnedgasesfromtheengines.Toremovedangerousemissionthatpollutestheair.Toreduceexhaustnoises.Togetridoftheexhaustgases.排放系統(tǒng)要實現(xiàn)四個功能：1、收集發(fā)動機的廢氣。2、去除污染空氣的排放物。3、減少排放噪音。4、排出廢氣。Exhaustgasescontaincarbonmonoxide,unburnedhydrocarbons,andoxidesofnitrogen.Sincealloftheseareharmful,theexhaustsystemisdesignedtoreducethemasmuchaspossible.IntheUnitedStaresallmodernautomobileshaveemissioncontrolsystems.汽車廢氣包含一氧化碳，未燃燒的碳氫化合物和氮氧化合物。所有的這些都是有害的，排放系統(tǒng)設(shè)計要盡可能多減少這些有害物質(zhì)。美國所有的現(xiàn)代車都配備了排放系統(tǒng)。Thecoolingsystemremovesexcessiveheatfromtheengine.Thetemperatureinenginecombustionchambersisabout1094C.Sincesteelmeltsataround1354C,thisheatmustbecarriedawaytopreventenginedamage.Airandacoolantareusedtocarryawaytheheat.Theradiatorisfilledwithacoolant.Thewaterpumpcircuitsthiscoolantthroughtheengineandthewallsoftheengineblockandhead.Heatalsoisremovedbytheradiatorfan,whichdrawsairthroughthenarrowfinsoftheradiator.Thissystemalsosuppliesheattothepassengercompartmentandthewindowdefroster.冷卻系統(tǒng)去除發(fā)動機多余的熱量。 發(fā)動機燃燒室的溫度可以達到1094攝氏度。鋼的熔點大約是1354攝氏度，發(fā)動機多余的熱量必須消除來防止發(fā)動機過熱?？諝夂屠鋮s劑用來帶走這個熱量。散熱器內(nèi)裝滿了冷卻劑。水泵使冷卻劑在發(fā)動機、發(fā)動機殼體和發(fā)動機蓋循環(huán)流動。也可以使用冷卻風(fēng)扇來降溫。冷卻風(fēng)扇將風(fēng)從散熱器狹窄的孔徑吹出，從而帶走熱量。這個系統(tǒng)可以給乘客艙和車窗除霜器提供熱量。Thelubricationsystemisimportantinkeepingtheenginerunningsmoothly.Motoroilisthelubricantusedinthesystem.Thelubricationsystemhasfourfunctions:Itcutsdownfrictionbycoatingmovingpartswithoil.Itproducesasealbetweenthepitonringsandthecylinderwalls.Itcarriesawaysludge,dirt,andacids.Itcoolstheenginebycirculatingthemotoroil.潤滑系統(tǒng)非常重要，它使得發(fā)動機平滑工作。潤滑系統(tǒng)使用機油作為潤滑劑。潤滑系統(tǒng)有四個功能： 1、通過運動部件油膜，它可以減小摩擦。 2、它在活塞環(huán)和氣缸壁之間產(chǎn)生油封。3、它可以帶走金屬碎屑、雜污和酸。 4、通過機油的循環(huán)，它可以冷卻發(fā)動機。Tokeepthissystemworkingeffectively,oilfiltersandmotoroilmustbechangeregularly.Allothermovingpartsinanautomobilemustalsobelubricated.Theseincludethetransmission,differential,wheelbearings,andsteeringlinkage.為了使得潤滑系統(tǒng)有效工作，機油濾清器和機油必須定期更換。汽車內(nèi)所有的運動部件都必須要潤滑，這包括變速器、差速器、輪軸軸承和轉(zhuǎn)向傳動機構(gòu)。1.2.3ThepowertrainThepowertrain,ordrivesystem,deliverspowerfromtheenginetothewheels.Thepowerfromtheenginemovesthroughthetransmission.Transmissionsareeitherstandard,withamanualshiftleverandfootclutch,orautomatic.傳動系統(tǒng)將發(fā)動機動力傳給車輪。來自發(fā)動機的動力傳遞給變速器。變速器可以是一個帶手動換檔桿和離合器的手動變速器或者自動變速器。Thetransmissionhasgearsthatcontroltheamountofpowerdeliveredtothewheels.Thetransmissionincreasesthepower(torque)tostartthecarmoving.Thistorqueisreducedwhenthetransmissionchangesgearsathigherspeeds.Thetransmissionalsocontainsasetofgearsthatcanreversethedirectionofthewheels.Thetransmissiondeliversthepowertothedifferential.Adrive(orpropeller)shaftwithuniversaljointsateitherendofthedriveshaftallowsaxlemovementoffront-engine,rear-wheeldrivecars.Theseflexibleuniversaljointpreventthedriveshaftfrombreaking.Thedifferentialdeliverspowertothewheelsthroughaxle.Certaingearsallowonewheeltoturnfasterthantheotherwheelwhenthevehicleisturningacorner.變速器使用齒輪來控制傳遞到車輪力矩的大小。當(dāng)車輛起步時，變速器增大扭矩。當(dāng)車速增大，變速器改變齒輪來減小扭矩。變速器還有一套使得車輪反向運動的齒輪。變速器將扭矩傳遞給差速器。發(fā)動機前置后輪驅(qū)動轎車的驅(qū)動軸兩側(cè)裝有萬向節(jié)，可允許產(chǎn)生軸向運動。萬向節(jié)防止驅(qū)動軸斷裂。差速器通過半軸將扭矩傳遞給車輪。當(dāng)車輛轉(zhuǎn)彎時，齒輪使得一側(cè)車輪比另一側(cè)車輪旋轉(zhuǎn)得更快。Thesearethebasicsystemsoftheautomobile.Eachofthesystemsisdesignedforaspecificjob.以上就是汽車的基本系統(tǒng)。每個系統(tǒng)都為了一個專門的功能而設(shè)計。ExercisesTheautomobile'sfurtherdevelopmentwillbedeterminedbyalreadyexistingandsteadilyincreasingrequirements,byadditionalfurtherrequirementsandbythetechnicalpossibilitiesformeetingtheserequirements.Thefollowingfocalpointsfordevelopmentandresearcheffortscanbediscerned:汽車的進一步發(fā)展取決于已經(jīng)存在的、目前穩(wěn)定增長和未來的需求以及為了滿足這些需求的技術(shù)。下來給出發(fā)展研究的幾個要點：Furtherimprovementsoftheautomobilethroughproductsinnovationinallclassisfunctions,i.e.performance,fueleconomy,environmentalimpact,safety,comfortandreliability.Furtherdevelopmentofnewtechnologiessuchaselectrics,alternativematerials,newtestandproductionmethods.Long-rangesolutionsfortrafficproblemssuchashighwaycongestion,smogincitiesandcarbondioxideenrichmentofouratmosphere.傳統(tǒng)功能的產(chǎn)品革新，比如：性能、燃油經(jīng)濟性、環(huán)境友好、安全、舒適性和可靠性。新技術(shù)的發(fā)展，比如：電氣、替代材料、新型測試和生產(chǎn)技術(shù)。解決交通問題的技術(shù)，比如：交通擁堵，城市煙霧和溫室效應(yīng)。Unit2AutomotiveenginePurposeandlocationsofenginesThepurposeofanautomobileengineistosupplythepowerneededtomovethevehicle.Theengineproducesthispowerbyburningfuelinsideit.Becausetheengineburnsfuelinside,orinternally,theengineisknownasaninternalcombustionengine(ICE).汽車發(fā)動機的功用是提供汽車行馳所需的動力。發(fā)動機通過發(fā)動機內(nèi)部燃燒燃料來產(chǎn)生這個動力。由于燃料燃燒在發(fā)動機內(nèi)部進行，這種發(fā)動機被稱作內(nèi)燃機。Mostautomobileenginesarelocatedatthefrontofthevehicle.Manyenginesdrivetherearwheels.Thisrequiresalongdriveshaftextendingfromthefrontwheelstotherearwheels.Otherenginesdrivethefrontwheels.Intherear-wheel-drivearrangement,theenginesitslongitudinally.Itslongdimensionisfromfronttoback.對于大多數(shù)汽車，發(fā)動機布置在汽車前部。許多發(fā)動機驅(qū)動后輪，這就要求從前輪到后輪的長驅(qū)動軸。其余發(fā)動機驅(qū)動前輪。對于后輪驅(qū)動的汽車而言，發(fā)動機由前到后縱向布置。Inthefront-wheel-drivearrangement,theenginesitscrosswise,transversely.Witheitherarrangement,thepoweriscarriedtothedrivewheels(rearorfront)bygearsandshafts.對于前輪驅(qū)動的布置，發(fā)動機橫置。無論哪種布置方式，能量都是通過齒輪和傳動軸傳到驅(qū)動輪(前輪或后輪)。Somecarshavetheenginemountedinbackofthefrontseat.Thisiscalledamid-enginearrangement.Othercarshavebeenbuiltwiththeenginemountedattherear,inbackofrearseat.TheVolkswagen “beettlrear.有些汽車的發(fā)動機位于前排座椅的后面。這種布置被稱為發(fā)動機中置。還有些汽車的發(fā)動機位于后部，安置在后排座椅后面。大眾汽車的甲殼蟲就是發(fā)動機后置的一個例子。EnginetypesVariouskindsofengineareusedinautomotivevehicles.Thetwomajortypesare:Thepistonengineinwhichpistonsmoveupanddown,orreciprocate,intheenginecylinder.Thisistheengineusedinallcarestoday,exceptforsomemodelsofMazda.TheWankelrotaryengineinwhichrotate,orspin.TheMazdaMotorCorporationofJapanisthemajormanufacturerofthisengine.汽車上使用著不同種類的發(fā)動機。它們可以分成兩大類：1、往復(fù)活塞式發(fā)動機：發(fā)動機在氣缸內(nèi)作上下往復(fù)運動。除了馬自達公司的幾款以外，現(xiàn)今幾乎全部轎車都采用這種發(fā)動機。2、轉(zhuǎn)子發(fā)動機：活塞在氣缸內(nèi)作旋轉(zhuǎn)運動。日本的馬自達公司是這類發(fā)動機的主要生產(chǎn)商。Therearetwotypesofpistonengines-sparkignition(SI)andcompressionignition(CI).Spark-ignitionenginesuseanelectricsystemwithsparkplugs.Electricsparksatthesparkplugsignite,orsetfire,thefuelintheenginecylinders.Thecombustionofthefuelmakestheenginerunandproducepower.Thisistheengineusedinmostproducepower.Thisisthetypeofengineusedinmostautomotivevehicles.活塞式發(fā)動機可以分為兩類：點燃式和壓燃式。點燃式發(fā)動機使用帶火花塞的點火系統(tǒng)?；鸹ㄈ碾娀鸹c燃發(fā)動機氣缸內(nèi)的燃料。燃料燃燒驅(qū)動發(fā)動機，并做功。這是大多數(shù)動力源采用的發(fā)動機，也是大多數(shù)汽車采用的發(fā)動機形式。Thecompression-ignitionengineusestheheatofcompressiontoignitethefuel.Whenairiscompressed,itgetsveryhot.Inthedieselengine,theairiscompressedsomuchthatitstemperaturegoesupto538degreesCelsiusorhigher.Thedieselfuelissprayedintothisveryhotairandisignitedbytheheat.Someautomobileshavedieselengines.Manyheavy-dutytrucksandbusesarepoweredbydieselengines.壓燃式發(fā)動機使用壓縮產(chǎn)生的熱量來點燃燃料。當(dāng)空氣被壓縮，它可以達到非常高的溫度。對于柴油式發(fā)動機，壓縮空氣可以使得空氣溫度達到 538度或者更高。此時，柴油被噴射到這熾熱的空氣中，被空氣的熱量點燃。一些轎車使用柴油發(fā)動機。重型卡車和客車普遍使用柴油發(fā)動機。Thereareotherenginesstillintheexperimentalstagethatmightsomedaybecomeimportant.Theseincludegas-turbineengines,steamengines,Stirlingengines,andelectricmotors.還有一些目前尚且處于試驗階段，但未來可能會非常重要的發(fā)動機，比如：燃氣渦輪機、蒸汽機、斯特靈發(fā)動機和電動機。BasicenginesystemsAspark-ignitionenginerequiresfourbasicsystemstorun.Dieselenginesrequiresthreeofthesesystems.Theyarefuelsystem,ignitionsystem(expectdiesel),lubricatingsystemandcoolingsystem.Eachperformsabasicjobinmakingtheenginerun.Thesearedescribedbrieflybelow.點燃式發(fā)動機運轉(zhuǎn)需要 4個基本系統(tǒng)，而柴油發(fā)動機需要 3個基本系統(tǒng)。它們是燃油系統(tǒng)、點火系統(tǒng)(柴油發(fā)動機不需要)，潤滑系統(tǒng)和冷卻系統(tǒng)。每個系統(tǒng)實現(xiàn)一個基本功能來使得發(fā)動機運轉(zhuǎn)。下文將簡短介紹這些系統(tǒng)。fuelsystemThefuelsystemsuppliesgasolineordieselfueltotheengine.Thisfuelismixedwithairtomakeacombustiblemixture(amixturethatwillrun).Eachcylinderisrepeatedlyfilledwiththemixture.Then,themixtureisignitedorburned,producinghighpressure.Thehighpressuremakesthepistonmove(orrotorsspin).Thisturnsshaftsthatrotatethewheels,causingthevehicletomove.燃油系統(tǒng)給發(fā)動機提供汽油或柴油燃料。燃油與空氣混合形成可燃混合氣。發(fā)動機的每個氣缸重復(fù)充滿這種可燃混合氣，然后它們被點燃或壓燃，產(chǎn)生高壓。這個高壓使得發(fā)動機活塞運動(或者轉(zhuǎn)子旋轉(zhuǎn)) ，驅(qū)動軸來旋轉(zhuǎn)車輪，從而使得汽車行駛。ignitionsystemEverytimethefuelsystemdeliversair/fuelmixturetoacylinder,theignitionsystemfollowsupbyadeliveringanelectricspark.Thisignitethemixturewhichcreatesthehighpressurethatmovesthepistonsandturnsthecarwheels.Theactionisrepeatedmanytimeseachsecondwhiletheengineisrunning.每當(dāng)燃油系統(tǒng)將可燃混合氣送至氣缸， 點火系統(tǒng)接著就發(fā)出電火花來點燃缸內(nèi)的可燃混合氣， 從而產(chǎn)生高壓，使得活塞運動和汽車行駛。當(dāng)發(fā)動機運轉(zhuǎn)時，每秒鐘要點火多次。Theignitesystemtakesthelowvoltageofthebatteryandbuildsituptoaveryhighvoltage:ashighas47,000voltsinsomesystems.Thishighvoltagejumpsthegapsinthesparkplugs,producingthesparksthatignitetheair/fuelmixtureintheenginecylinders.點火系統(tǒng)將電池的低電壓升壓到高壓。對于某些系統(tǒng)，可以達到 47000伏。這個高壓擊穿火花塞間隙，產(chǎn)生電火花，點燃發(fā)動機氣缸內(nèi)的可燃混合氣。ThelubricatingsystemTheenginehasmanymovingmetalparts.Ifmetalpartsrubagainsteachother,theywillwearrapidly.Topreventthis,engineshavelubricatingoil.Theoilgetsbetweenthemetalpartssotheyslideontheoil,andnotoneachother.發(fā)動機有許多運動金屬部件。如果這些金屬部件相互摩擦，那它們磨損就會很快。為了防止這種情況，發(fā)動機使用潤滑油。潤滑油在金屬部件之間，使得金屬部件在油膜上滑動，而不是彼此之間的摩擦。Thelubricatingsystemhasanoilpanatthebottomoftheenginewhichholdsseveralquarts(liters)ofoil.Anoilpump,drivenbytheengine,sendsoilfromthisreservoirthroughtheengine.Aftercirculatingthroughtheengine,theoildropsbacktotheoilpan.Theoilpumpcontinuestocirculatetheoilaslongastheengineisrunning.發(fā)動機潤滑系統(tǒng)在發(fā)動機底部有一個儲存幾升汽油的油底殼。由發(fā)動機驅(qū)動的油泵將油從油底殼泵到發(fā)動機循環(huán)流動。在發(fā)動機循環(huán)后，潤滑油流回到油底殼。只要發(fā)動機在運轉(zhuǎn)，油泵就始終使?jié)櫥脱h(huán)流動。CoolingsystemWherethereisfire(combustion),thereisheat.Burningoftheair/fuelmixtureraisesthetemperatureinsidetheenginecylindersseveralthousanddegrees.Someofthisheatproducesthehighpressurethatmovesthepistonstoproducepower.Someoftheheatleavesthecylinderswiththeexhaustgas.Theexhaustgasiswhatisleftaftertheair/fuelmixtureburns.Itisclearedoutofthecylindersafterthecombustioniscomplete.哪里有燃燒，哪里就有熱量?？扇蓟旌蠚獾娜紵沟冒l(fā)動機氣缸內(nèi)溫度上升數(shù)千度。部分熱量產(chǎn)生高壓來驅(qū)動活塞產(chǎn)生動力。部分熱量伴隨排放氣體被帶出氣缸。排放氣體指的是可燃混合氣燃燒后剩余物。當(dāng)燃燒結(jié)束，排放氣體被排出氣缸。Someoftheheatisremovedbythecirculatingoil.Afterthehotoildropsdownintotheoilpan,theoilgivesupsomeofthisheattotheairpassingundertheoilpan.Therestoftheheatisremovedbythecoolingsystem.部分熱量被循環(huán)油帶走。當(dāng)溫度較高的油流回到油底殼，熱量通過油底殼下流動的空氣帶走。剩余的熱量就要使用冷卻系統(tǒng)來帶走。OtherenginesystemAnenginewillrunwiththefourbasicsystemsdescribedabove-fuel,ignition,lubricatingandcooling.However,threeotherrelatedsystemsarealsonecessary.Thesearetheexhaustsystem,theemission-controlsystem,andthestartingsystem.具備上述的燃油、點火、潤滑和冷卻系統(tǒng)，發(fā)動機就可以運轉(zhuǎn)。但是，其余相關(guān)的 3個系統(tǒng)也是非常必需的。它們是排放系統(tǒng)、排放控制系統(tǒng)和啟動系統(tǒng)。Theexhaustsystemreducesthenoiseoftheburnedgasesleavingtheenginecylindersandcarriestheseexhaustgasessafelyawayfromthepeopleinthecar.Theemission-controlsystemisrequiredbylawtoreducetheairpollutiontheenginecouldproduce.Thestartingsystemisneededtocranktheengine.Abatteryprovidestheelectricpowertooperatethestartingmotorandtheignitionsystemduringcranking.排放系統(tǒng)減少發(fā)動機氣缸可燃混合氣燃燒時的噪音，并且將廢氣安全帶走，使其遠離車廂內(nèi)的人。排放控制系統(tǒng)是法律強制要求的，用來減少發(fā)動機產(chǎn)生的空氣污染。啟動系統(tǒng)是用來啟動發(fā)動機。啟動過程中，由電池給啟動電機和點火系統(tǒng)提供能量。EnergyconversionTheinternalcombustionengineisadeviceusedtoconvertthechemicalenergytothefuel(gasolineordieselfuel)intoheatenergy,andthentoconvertthisheatenergyintousablemechanicalenergy.Thisisachievedbycombiningtheappropriateamountsofairandfuel,andburningthemixtureinanenclosedcylinderatacontrolledrate.Amovablepistoninthecylinderisforceddownbytheexpandinggasesofcombustion.發(fā)動機是一個將燃料(汽油或柴油)的化學(xué)能轉(zhuǎn)化成熱能，再將熱能轉(zhuǎn)化成可利用的機械能的裝置。實現(xiàn)這個能量的轉(zhuǎn)化是通過混合適當(dāng)?shù)目諝夂腿加停⒃诿芊獾臍飧變?nèi)以一個可控的速率燃燒這個可燃混合氣來實現(xiàn)的。燃燒產(chǎn)生的膨脹氣體強迫氣缸內(nèi)的活塞運動。Anaverageair/fuelratioforgoodcombustionisabout15partsofairto1partoffuelbyweight.Thismeansthatforeverygallonofgasolineburned,theoxygenisabout9,000to10,000gallonsofairisrequired.Airisabout21%oxygenand78%nitrogen.可燃燒良好的空燃比，按質(zhì)量大約是 15:1。這就意味著燃燒1加侖汽油需要的9000到10000加侖的空氣里的氧氣。空氣大約有 21%的氧氣和78%的氮氣。Dieselengineoperateonamuchwiderair/fuelratio,sinceairintakeisnotregulatedonmostdiesels.Ratiosmayrangefromabout20:1to100:1.Thefact,plusthehighcompressionofthediesel,makesitaveryfuelefficientengine.由于大多數(shù)的柴油機并不控制進氣，柴油機的空燃比范圍很寬，從20:1到100:1。再加上柴油混合氣具有很高的壓縮比，這使得柴油機的效率很高。Themovablepistoninthecylinderisconnectedtothetopofaconnectingrod.Thebottomoftheconnectingrodisattachedtotheoffsetportionofacrankshaft.Asthepistonisforceddown,thisforceistransferredtothecrankshaft,causingthecrankshafttorotate.Thereciprocating(backandforthorupanddown)movementofthepistonisconvertedtorotary(turning)motionofthecrankshaft,whichsuppliesthepowertodrivethevehicle.氣缸內(nèi)的活塞與連桿的上部相連，而連桿的下部與曲軸的偏移部連接。因此，當(dāng)活塞向下運動時，這個運動傳遞到曲軸，使得曲軸旋轉(zhuǎn)?；钊耐鶑?fù)運動(前后或者上下)就轉(zhuǎn)化為曲軸的旋轉(zhuǎn)運動，從而給汽車行駛提供動力。Theefficiencyoftheinternalcombustion,reciprocatingpistonengineinconvertingthepotentialenergyinfuelintomechanicalenergyisonlyabout33%.Oftheavailableheatenergyinthefuel,aboutone-thirdislostthroughthroughtheexhaustsystemandone-thirdisabsorbedanddissipatedbythecoolingsystem.Oftheremainingone-third,aboutone-halfislostthroughavailableatthevehicle'sdrivewheels.往復(fù)活塞式內(nèi)燃機將燃料的能量轉(zhuǎn)化為機械能的效率大約是 33%。燃料中可利用的熱量有三分之一通過排氣系統(tǒng)丟失掉，另有三分之一被冷卻系統(tǒng)吸收和帶走，剩下的三分之一大約有一半的能量在汽車的驅(qū)動輪消耗掉。Theoverallefficiencyofthedieselengineisconsiderablyhigherthanthatofthegasolineengine.Thereasonforthisare:thehighercompressionratio,thehigherair/fuelratio,andthehigherheatvalueofthefuel.Theusefulpowerdevelopedatthedrivewheelsbyadieselengineisabout25%comparedto15%byagasoline.與汽油機相比，柴油機的總體效率要高很多。這是因為柴油機具有更高的壓縮比，更高的空燃比，柴油的熱量也要更高。對于柴油機，驅(qū)動輪得到的能量大約可以達到總能量的 25%,而汽油機只有15%。fourstroke-cyclegasolineengineoperationThemovementofthepistonfromitsuppermostposition(TDC,topdeadcenter)toitslowestposition(BDC,bottomdeadcenter)iscalledastroke.Mostautomobileenginesoperateonthefourstroke-cycleprinciple.Aseriesofeventsinvolvingfourstrokesofthepistoncompletesonecycle.Theseeventsare:⑴theintakestroke,(2)thecompressionstroke,(3)thepowerstroke,and(4)theexhauststroke.Tworevolutionsofthecrankshaftandonerevolutionofthecamshaftarerequiredtocompleteonecycle.活塞從它在氣缸內(nèi)的最高位置 (上止點)運動到最低位置(下止點)稱為一個沖程。大多數(shù)汽車發(fā)動機采用四沖程工作循環(huán)，由活塞的四個沖程組成一個工作循環(huán)，分別是：進氣沖程、壓縮沖程、作功沖程和排氣沖程。發(fā)動機的一個工作循環(huán)需要曲軸旋轉(zhuǎn)兩次，凸輪軸旋轉(zhuǎn)一次。Ontheintakestrokethepistonispulleddowninthecylinderbythecrankshaftandconnectingrod.Duringthistimetheintakevalveisheldopenbythecamshaft.Sincethepistonhasmoveddowninthecylinder,creatingalow-pressurearea(vacuum),atmosphericpressureforcesamixtureofairandfuelpasttheintakevalveintothecylinder.Atmosphericpressureisapproximately14.7poundspersquareinch(about101.35kilopascals)atsealevel.Pressureinthecylinderduringtheintakestrokeisconsiderablylessthanthis.Thepressuredifferenceistheforcethatcausestheair/fuelmixturetoflowintothecylinder,sincetheliquidoragas(vapor)willalwaysflowfromahigh-pressuretoalow-pressurearea.吸氣沖程過程中，氣缸內(nèi)的活塞被曲軸和連桿向下拉動。此時，凸輪軸使得進氣門打開。由于活塞在氣缸壁向下運動，產(chǎn)生了一個低壓區(qū)(真空區(qū)) ，大氣壓力使得可燃混和氣從進氣門進入氣缸。海平面的大氣壓大約是每平方英寸14.7磅(大約101.35千帕)。吸氣沖程時，氣缸內(nèi)的壓力要遠遠小于大氣壓。由于液體和氣體總是從高壓區(qū)流向低壓區(qū)，因此，氣缸內(nèi)外的壓力差就使得可燃混和氣流入氣缸。AsthepistonismovedupbythecrankshaftfromBDC,theintakevalvecloses.Theair/fuelmixtureistrappedinthecylinderabovethepiston.Furtherpistontravelcompressestheair/fuelmixturetoapproximatelyone-eighthofitsoriginalvolume(approximately8:1compressionratio)whenthepistonhasreachedTDC.Thiscompletesthecompressionstroke.當(dāng)曲軸推動活塞從下止點起向上運動，進氣門關(guān)閉?？扇蓟旌蜌獗幌拗圃诨钊陨系臍飧讌^(qū)域內(nèi)。當(dāng)活塞達到上止點時，活塞壓縮可燃混合氣至其原有容積的 1/8(大約8:1的壓縮比)。此時，壓縮沖程結(jié)束。WhenthepistonisatornearTDC,theair/fuelmixtureisignited.Theburningoftheair/fuelmixture(combustion)takesplaceatacontrolledrate.Expansionoftheburningmixturecausesarapidriseinpressure.Theincreasedpressureforcesthepistondownonthepowerstroke,causingthecrankshafttorotate.當(dāng)活塞達到或接近上止點時，可燃混和氣被點燃，并且在一個可控的節(jié)奏下進行。可燃混和氣的膨脹使得壓力急劇上升，并推動活塞向下運動作功，使得曲軸旋轉(zhuǎn)。當(dāng)活塞達到或接近上止點時，可燃混和氣被點燃，并且在一個可控的節(jié)奏下進行?？扇蓟旌蜌獾呐蛎浭沟脡毫眲∩仙⑼苿踊钊蛳逻\動作功，使得曲軸旋轉(zhuǎn)。Attheendofthepowerstroke,thecamshaftopenstheexhaustvalve,andtheexhauststrokebegins.Remainingpressureinthecylinder,andupwardmovementofpiston,forcetheexhaustgasesoutofthecylinder.Attheendoftheexhauststroke,theexhaustvalveclosesandtheintakevalveopens,repeatingtheentirecycleofeventsoverandoveragain.作功沖程結(jié)束時，凸輪軸打開排氣門，排氣沖程開始。氣缸內(nèi)剩余的壓力和活塞向上的運動把廢氣排出氣缸。排氣沖程結(jié)束時，排氣門關(guān)閉，進氣門開啟，從而再次重復(fù)整個循環(huán)。Tostarttheengine,somemethodofcrankingtheengineisrequiredtoturnthecrankshaftandcausepistonmovement.Thisisdonebythestartermotorwhentheignitionkeyisinthestartposition.Whensufficientair/fuelmixturehasenteredthecylindersandisignited,thepowerstrokescreateenoughenergytocontinuecrankshaftrotation.Atthepoint,theignitionkeyisreleasedtotherunpositionandstarterisdisengaged.為了起動發(fā)動機，需要轉(zhuǎn)動曲柄來使得活塞運動。當(dāng)點火開關(guān)置于起動位置時，起動電機轉(zhuǎn)動曲柄，起動發(fā)動機。當(dāng)足量的可燃混和氣進入氣缸并被點燃，作功沖程產(chǎn)生的能量足以使得曲軸連續(xù)轉(zhuǎn)動。此時，點火開關(guān)釋放到正常位置，起動機推出嚙合。Sufficientenergyisstoredintheflywheelandotherrotatingpartsonthepowerstroketomovethepistonandrelatedpartsthroughtheotherthreestrokes(exhaust,intake,andcompression).Theamountofair/fuelmixtureallowedtoenterthecylinderdeterminesthepowerandspeeddevelopedbytheengine.在作功沖程中，大量的能量被儲存在飛輪和其他旋轉(zhuǎn)部件上，從而在其余三個沖程中可以使得活塞和相連部件運動。進入氣缸的可燃混合氣的數(shù)量決定了該發(fā)動機的功率和轉(zhuǎn)速。2ExercisesIWhatisthepurposeofanautomotiveengine?ITosupplythepowerneededtomovethevehicle.Whatisthedifferencebetweenagasolineengineandadieselengine?Agasolineengineusesanelectricignitionsystemwithsparkplugstoignitethefuel.Andadieselengineusestheheatofcompressiontoignitethefuel.Whatarethebasicsystemstorunaspark-ignitionenginerequired?Fuelsystem,ignitionsystem,lubricatingsystemandcoolingsystem.Listthestrokesofafour-stroke-cyclegasolineengineoperation.Theintakestroke,thecompressionstroke,thepowerstrokeandtheexhauststroke.Whatisthefunctionoftheflywheel?Itisusedtostoresufficientenergytomovethepistonandrelatedpartsthroughtheotherstrokes(exhaust,intakeandcompression).n1Acarusuallyhasapistonengine.Itconsistsofseveralmovingpart:pistons,connectingrods,crankshaft,camshaft,valvelifters,intakevalvesandexhaustvalves.Thecastironoraluminumengineblockholdsthemovingparts.Theengineblockhasaseriesofholeswhicharecalledcylinders.ThecylinderscanbearrangedinlineorinaV-shapeandintheupperpartoftheblock.Eachcylinderholdsapistonandtheconnectingrod.Acircularringisusedtosealthesmallgapbetweenthepistonandthecylinderwall.Thelowerpartoftheblockiscalledcrankcasewhichholdsthecrankshaftwithbearingmounts.Pistonsareconnectedtothecrankshaftbyconnectingrods.汽車一般使用活塞式發(fā)動機?；钊桨l(fā)動機由活塞、連桿、曲軸、凸輪軸、氣門挺桿、進氣門和排氣門等運動部件組成。這些運動部件安置在鑄鐵或鋁合金機體內(nèi)。發(fā)動機體上有些凹洞，這些凹洞被稱作氣缸。氣缸在機體上部呈直列式或 V型排列。每個氣缸都有活塞和連桿?；钊蜌飧妆谥g的微小縫隙通過一個圓環(huán)密封。機體的下部是曲軸箱，里面是帶有軸承的曲軸?；钊颓S之間通過連桿連接。2Thecylinderheadsarethetopcoversofthecyl