專業(yè)英語完整版

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1.英譯中

1、engine發(fā)動機2、piston活塞3、crankshaft曲軸4、clutch離合器5、chassis底盤6、automobile汽車7、body車身8、lightvehicle輕型車

9、heavycommercialvehicle重型商務車10、truckdeck行李箱蓋11、hood（發(fā)動機）罩12、powerunit動力裝置13、compressionstroke壓縮行程14、transmission變速器15、camshaft傳輸凸輪軸16、propellershaft傳動軸17、powertrain傳動系18、carburetor化油器19、washer墊圈20、steeringsystem轉(zhuǎn)向系統(tǒng)21、suspensionsystem懸架系統(tǒng)22、brakingsystem剎車系統(tǒng)23、torqueconverter變矩器

24、timinggear正時齒輪25、finaldrive主減速器，后橋26、differential差速器27、internalcombustionengine內(nèi)燃機28、electricalequipment電氣設備29、driveshaft傳動軸30、brakeshoe制動蹄31、flywheel飛輪32、steeringcolumn轉(zhuǎn)向柱33、leafspring鋼板彈簧34、coilspring螺旋簧35、waterjacket水套36、airbag氣囊37、oxygensensor氧氣傳感器38、overhead-camshaft頂置凸輪軸39、multiplexbus多路傳輸總線40、throttlevalve節(jié)氣門41、exhaustpipe排氣管42、torsionbar扭桿43、differentialgear差動齒輪44、distributor分電器45、toe-in輪胎前束46、sungear太陽輪47、planetarygear行星齒輪48、regulator調(diào)節(jié)器49、axleshaft半軸50、valvetiming氣門正時51、frontsuspension前懸架52、intakevalve進氣門53、kineticenergy動能54、retardingbraking緩速移動55、connectingrod連桿56、engineblock發(fā)動機缸體57、gasolineengine汽油機58、drumbrake鼓式制動器59、servicebraking行車制動60、combustionchamber燃燒室61、steeringwheel轉(zhuǎn)向輪62、aircooling空氣冷卻63、sparkplug火花塞64、starter起動機65、alternator交流發(fā)電機66、valvesystem閥門系統(tǒng)67、valveclearance氣門間隙

68、valvetiming氣門正時69、valvetrain氣門傳動70、gearratio傳動比71、inlineengine直列發(fā)動機72、distributedsystem分布系統(tǒng)73、variedcylindercount可變的氣缸數(shù)74、excess-airfactor過量空氣系數(shù)75、air-fuelratio空燃比76、dieselengine柴油發(fā)動機77、parkingbraking駐車制動78、discbrake盤式制動79、fuelpump燃料80、thermostat節(jié)溫器81、air-fuelmixture混合空氣燃料82、steeringbox轉(zhuǎn)向器83、shockabsorber減振器84、sweptvolume有效容積85、clearancevolume余隙容積86、intakemanifold進氣總管87、cylindersleeve氣缸套88、pistonring活塞環(huán)89、crankcase曲軸箱90、universaljoint萬向節(jié)91、liquidcooling液體冷卻92、cylinderhead氣缸蓋93、weakmixture稀混合氣94、richmixture濃混合氣95、inductionstroke進氣行程96、compressionstroke壓縮行程97、powerstroke做功行程98、exhauststroke排氣行程99、enginelubrication發(fā)動機潤滑100、compressionratio壓縮比101、filter濾清器102、sliding-meshtransmission滑動嚙合變速器103、controllerareanetwork(CAN)控制器局域網(wǎng)104、constant-meshtransmission常嚙合變速器105、synchro-meshtransmission同步嚙合傳動106、windscreenwiper風窗刮水器107、seat-belt座椅安全帶108、continuouslyvariabletransmission無級變速器109、frontwheeldrive前輪驅(qū)動110、anti-theftsystem防盜系統(tǒng)

111、brakeby-wire線控制動112、fault-tolerant容錯113、enginecapacity發(fā)動機容量114、steeringsystem轉(zhuǎn)向系統(tǒng)115、chargingsystem充電系統(tǒng)116、passengerinertialrestraintsystem慣性約束系統(tǒng)2、英文縮寫1汽油直接噴射GDI2廢氣再循壞EGR3自動變速器AT4防抱死制動系統(tǒng)ABS5多用途汽車MPV6上止點TDC7前輪驅(qū)動FWD8電子穩(wěn)定性程序ESP9車輛識別號VIN10電動助力轉(zhuǎn)向EPS11液力助力轉(zhuǎn)向HPS12多點燃油噴射MPI13手動變速器MT14運動型多用途車SUV15下止點BDC16全輪驅(qū)動AWD17電子控制模塊ECM18診斷故障代碼DTC19牽引力制動系統(tǒng)TCS20三元催化轉(zhuǎn)換器TWC21車載診斷裝置OBD22電子式氣閥控制EVC23無級變速器CVT24電液制動EHB25機電制動EMB26控制器局域網(wǎng)絡CAN27曲軸箱強制通風PCV28汽車工程學會SAE29智能型可變配氣正時和氣門升程VTEC30電子控制燃油噴射EFI31怠速控制ISC32歧管絕對壓力MAP33專業(yè)維修工具SST34車輛控制模塊VCM35內(nèi)部局域網(wǎng)LAN36汽車工程師協(xié)會SAE37空調(diào)AC38絕對壓力傳感器APS39電控制動力分配EBD40電子點火提前角ESA41無線遙控門鎖RKE42國際標準機構ISO43全球衛(wèi)星定位系統(tǒng)GPS44混合動力電動汽車HEV45低排放汽車LEV46發(fā)光二極管LED47液晶顯示器LCD48原裝設備制造廠OEM49頂置凸輪軸OHC50頂置氣門OHV51輔助約束系統(tǒng)SRS3.連線

1).CommonRailInjectionSystem共軌燃油噴射系統(tǒng)

2).Electronicvalvecontrol電子式氣閥控制

3).TurboChargerSystem渦輪增壓系統(tǒng)

4).0verheadCamshaftValveTrain頂置凸輪軸氣閥傳動

5).CarburetorFuelSystem化油器式燃油系統(tǒng)

6.Three-wayCatalyticConverter三元催化轉(zhuǎn)化器

7).Exhaust-gasrecirculation廢氣再循環(huán)

8).brakefluidreservoir制動液貯存箱

9).EvaporativeEmissionControl蒸發(fā)排放控制

10).fail-safemode失效安全模式判斷對錯

()1.Automobilepartscanbegroupedintothreemajorcategories:body,engineandchassis.

()2.BDCisthepositionofthecrankandpositionwhenthepistonisfartherfromthecrankshaft.

()3.Enginecapacityisthesweptvolumeofallthecylinders.

()4.Boreistheinternaldiameterofthecylinder.

()5.Gasolineengineiscalledacompression-ignitionengine.

()6.Dieselandgasolineenginearebothinternal-combustionengines.

()7.Thethreemostharmfulemissionsarehydrocarbons,carbondioxideandnitrogenoxides.

()8.Inenginestherearetwomethodsofcooling:aircoolingandliquidcooling.

(√)9.Alternatorinthevehicleonlyproduceselectricitytooperatethevariouselectricalcircuits.

()10.Whenthedriverturnsthesteeringwheel，thesteeringgeariscentered.

()11.StrokeisthedistancebetweenBDCandTDC.

()12.Ifenginecombustionoccurswithinthepowerchamber,theengineiscalledanexternalcombustionengine.

()13.TDCisthepositionofthecrankandpistonwhenthepistonisfartherawayfromthecrankshaft

()14.Dieseliscalledacompression-ignitionengine.

()15.Dieselenginehashighercompressionratiothangasolineengine.

()16.Theengineactsasthepowerunit.

()17.Thevehicleisclassifiedasrear-wheeldrivefront-wheeldrive,four-wheeldriveorall-wheeldrive.

()18.Whenavehicleiscorneredtheaxleshaftcanmaintainsitsdrivingaction.

()19.Exposedtotheair,drumbrakesradiatetheheattotheairbetterthandiscbrakes.

()20.Therearetwotypesoftransmissions-manualandautomatic.

()21.Inanautomobile,theelectricalvoltageiscreatedbychemicalactioninthestoragebatteryandbymagneticinductioninthealternator.

()22.Thechassisincludesthepowertrain,steering,suspension,andbrakingsystem.

()23.SweptvolumeisthevolumebetweenTDCandBDC.

()24.ClearancevolumeisthevolumeofthespaceabovethepistonwhenitisatTDC.()25.Compressionratioε=(sweptvolume+clearancevolume)/(clearancevolume).

()26.Thespark-ignitionengineoperatingstrokesareinductionstroke,compressionstroke,powerstrokeandexhauststroke.

()27.Thepurposeofthelubricationsystemistocirculateoilthroughtheengine.

()28.Rear-wheeldrivehasadvantagesoverfront-wheeldrive.

()29.Inordertoreducethespeedofthevehicle,thebrakeshavetoconvertthekineticenergytochemicalenergy.

()30.Since1976,allcarshaveuseddiscbrakesonthefrontwheels.

()31.Non-powerbrakesrelyonthedriver'sfootpressuretooperate.

()32.Therearsuspensionismorecomplicatedthanthefrontsuspension.()33.Whendischarging,PbOandPbintheLead-acidbatteryreactwithHSOtoformPbSO.()34.Thechargingsystemusesthemechanicalenergyoftheenginetogenerateelectricity.

()35.Passengerrestraintsystemsconsistofairbagandseat-belttighteningsystem.三、語句英譯中1.Theinternalcombustionengineismostcommon:thisobtainsitspowerbyburningaliquidfuelinsidetheenginecylinder.Therearetwotypesofengine:gasolineanddiesel.

內(nèi)燃發(fā)動機最常用的，它是通過燃燒發(fā)動機氣缸內(nèi)的液體燃料獲得動力。有兩種類型的發(fā)動機：汽油發(fā)動機和柴油發(fā)動機。2.Apowertraincanincludeaclutchformanualtransmissionoratorqueconverterforautomatictransmission,atransmission,adriveshaft,finaldriveanddifferentialgearsanddrivingaxles.動力傳動系包括一個供手動傳輸?shù)碾x合器或自動傳輸?shù)牧剞D(zhuǎn)換器、變速器、傳動軸、主減速器和差速器、驅(qū)動軸。3.Thechargingsystemprovideselectricalenergyforalloftheelectricalcomponentsonthevehicles.Themainpartsofthechargingsysteminclude:thebattery,thealternator,thevoltageregulator,achargingwarningandwiring.充電系統(tǒng)為車輛上的所有電氣元件提供電能。充電系統(tǒng)主要包括：電池、交流發(fā)動機、電壓調(diào)節(jié)器，充電報警指示燈和形成電路的導線。4.Theenginehashundredsofotherparts.Themajorpartsofengineareengineblock,engineheads,pistons,connectingrods,crankshaftandvalves.Theotherpartsarejoinedtomakesystem.Thesesystemsarethefuelsystem,intakesystem,ignitionsystem,coolingsystem,lubricationsystemandexhaustsystem.發(fā)動機有數(shù)百個零件。主要零件有發(fā)動機缸體，發(fā)動機缸蓋、活塞、連桿、曲軸和閥。其他的零件也形成了這一系統(tǒng)。這些系統(tǒng)是燃料系統(tǒng)、進氣系統(tǒng)、點火系統(tǒng)、冷卻系統(tǒng)、潤滑系統(tǒng)和排氣系統(tǒng)。5.Theengineblockisthebasicframeoftheengine.Allotherenginepartseitherfitinsideitorfastentoit.Itholdsthecylinders,waterjacketsandoil·galleries.Theengineblockalsoholdsthecrankshaft,whichfastenstothebottomoftheblock..發(fā)動機缸體是發(fā)動機的基礎結(jié)構。所有其他發(fā)動機零件要么裝在缸體內(nèi)，要么固定在缸體上。它承裝氣缸、水套和油道。發(fā)動機缸體還承裝固定于發(fā)動機體的底部的曲軸。6.Thepistonisanimportantpartofafour-strokecycleengine.Mostpistonsaremadefromcastaluminum.Thepiston,throughtheconnectingrod,transferstothecrankshafttheforcecreatedbytheburningfuelmixture.活塞是四沖程循環(huán)發(fā)動機的重要組成部分。大多數(shù)活塞是用鑄鋁制造的。通過連桿，活塞把燃燒燃料混合氣產(chǎn)生的力傳遞到曲軸上。7.Anelectronicvalvecontrolsystemreplacesthemechanicalcamshaft,controllingeachvalvewithactuatorsforindependentvalvetiming.TheEVCsystemcontrolstheopeningandclosingtimeandliftamountofeachintakeandexhaustvalvewithindependentactuatorsoneachvalve.電子氣閥控制系統(tǒng)替代機械凸輪軸，用執(zhí)行器控制每一個氣閥使它能獨立的氣閥正時。電子閥控制系統(tǒng)用每個氣閥上的獨立執(zhí)行器控制進氣閥和排氣閥的打開和關閉時間和提起量。8.Thedieselisusedforthemajorityofheavevehiclesandtheexcellentfueleconomymakesitanattractivealternativetothepetrolengineforlightcommercialvehicles,deliveryvansandtaxis.柴油用于大多數(shù)重型汽車，極好的燃料經(jīng)濟性使它成為一個吸引人的替代品相對于輕型商務車、和出租汽車。9.Adieselenginehasnodistributor,sparkplugs,orsparkplugs.Thefuelisignitedbyheatproducedbycompressingtheairinthecylinders.Forthisreason,thedieseliscalledacompression-ignitionengine.柴油發(fā)動機沒有分電器、火花塞或火花塞線。燃油通過氣缸內(nèi)壓縮空氣產(chǎn)生的熱點火。因此，柴油發(fā)動機又叫做壓縮點火發(fā)動機。10.Thefinaldifferencebetweenthegasolineanddieselenginesisinthewaythefuelisinjected.Thefuelinjectionsystemisthemostimportantpartofthedieselengine.汽油和柴油發(fā)動機之間的最后的差別在于燃油的噴射方法。燃油噴射系統(tǒng)是柴油發(fā)動機的最重要部分。11.Someformofcoolingmustbeprovidedtotakeawaytheheatfromthecylinderandworkingpartsofanengine.Thisheatcomesfromcombustionofthefuelandfromfrictionbetweenrubbingparts.某些形式的冷卻裝置必須被提供用來帶走發(fā)動機氣缸或者工作部件產(chǎn)生的熱量，這些熱量來自燃料的燃燒和活動部件的摩擦。12.Liquidcoolingsystemconsistsofseveralinterdependentpartsthatfunctiontogethertomaintainproperenginetemperatures.Thepartsinclude:radiator,fan,coolantrecoverysystem,coolantpump,waterjacket,thermostat,pressurecap,softplugs.液體冷卻系統(tǒng)包括一些互相依存的部分一起工作去維持發(fā)動機合適的溫度。這些部分包括:散熱器、風扇、冷卻劑回收系統(tǒng)、冷卻泵、水套、節(jié)溫器、壓力感應器、軟塞。13.Thepurposeofthelubricationsystemistocirculateoilthroughtheengine.Anenginemusthaveagoodlubricationsystem.Withoutit,thefrictionheatfromthecontactofthemovingpartswouldwearthepartsandcausepowerloss.潤滑系統(tǒng)的目標是保證潤滑油在發(fā)動機內(nèi)循環(huán)，一個發(fā)動機一定要有好的潤滑系統(tǒng)。沒有它，活動部件之間的摩擦生熱會損害部件和引起動力損失。14.Thefunctionofthepowertrainofanautomobileistoprovidetheforcesnecessaryforlocomotion.TheforcesareproducedbytheconversionintheICengineofthechemicalenergyinliquidfuelsintotheenergyofmotion.汽車傳動系的功能是為運動提供必要的動力。動力通過內(nèi)燃機內(nèi)部液體燃料的化學能向運動能量的轉(zhuǎn)變而產(chǎn)生。15.Adryclutchperformstwotasks:1)itdisengagestheenginefromthetransmissiontoallowforgearchanging,2)itisameansforgraduallyengagingtheenginetothedrivingwheels.干摩擦離合器執(zhí)行兩個任務：1.它使發(fā)動機從變速器中脫離出來來允許齒輪的改變，2.它使發(fā)動機逐漸與驅(qū)動輪嚙合。16.Tostarttheengine,thedrivermustdepresstheclutchpedal.Thisdisengagesthetransmissionfromtheengine.Tomovethecar,thedrivermustreengagethetransmissiontotheengine.為了起動發(fā)動機，駕駛員必須踩離合器踏板，這使變速器從發(fā)動機中脫離出來，為了使汽車運動，駕駛員必須使變速器和發(fā)動機重新嚙合。17.Anautomatictransmissionisadevicethatprovidesgearreduction,withresultingmultiplicationoftorque.Thegearrangesareautomaticallyselectedtoprovidethemostefficientoperationandthebesttorqueoutput.自動變速器是一個提供齒輪減速，用乘法改變扭矩的設備。齒輪范圍是被自動的選擇用來提供最有效的操作和最好的扭矩輸出。18.Automatictransmissionshavethreebasicsystemsatorqueconverter,agearsystemandahydraulicsystem.Thesefittogetherinaunitthatfastensdirectlybehindtheengine.自動變速器有三個基本系統(tǒng)—變矩器，齒輪系統(tǒng)和液壓系統(tǒng)。這些被安裝在同一裝置中且被直接固定在發(fā)動機后面。19.Whenavehicleiscorneredtheinnerwheelmovesthroughashorterdistancethantheouterwheel.Thismeansthattheinnerwheelmustslowdownandtheouterwheelmustspeedup.當車輛轉(zhuǎn)彎時，內(nèi)輪移動的距離相對于外部的車輪更短。這意味著內(nèi)部的車輪必須減速外部的車輪必須加速。20.Theservicebrakingsystemandtheparkingbrakingsystemhaveseparatecontrolandtransmissiondevices.Theservicebrakingsystemisnormallyfoot-operated,whiletheparkingbrakingsystemishand-operated.行車制動系統(tǒng)和駐車制動系統(tǒng)有單獨的控制和傳動裝置。行車制動系統(tǒng)正常用腳操作，而駐車制動系統(tǒng)則用手操作。21.Electrohydraulicbrakingsystemsaredesignedtoallowelectroniccontrolofvehiclebrakingwhileretainingareducedhydraulicsystem.電液制動系統(tǒng)被設計出來允許電子控制汽車制動然而保留了液壓系統(tǒng)。22.TheABSpreventsthewheelsfromlockingwhenthevehicleisoverbraked.Thevehiclethereforeretainsitsdirectionalstabilityandsteerabilityevenunderemergencybrakingonaslipperyroadsurface.ABS預防車輪被鎖死當車輛過度制動時，汽車會因此保留它的方向穩(wěn)定性和可控制性即使在滑的路面的緊急制動的情況下。23.Whilethesteeringsystemmaylookcomplicated,itworksquitesimply.Whenadriverdrivesacarstraightdowntheroad,thesteeringgeariscentered.Thegearholdsthelinkagecenteredsothatthewheelsandtirespointstraightahead.盡管轉(zhuǎn)向系看上去很復雜，但它工作相當簡單。當駕駛員駕駛車輛直行時，轉(zhuǎn)向齒輪居中。該齒輪保持中位，車輪向前直行。24.Thesteeringsystemmustguaranteeeasyandsafesteeringofthevehicle:itmustbepossibletoturnthefrontwheelsintothepositioncorrespondingtoaturningcirclewitharadiusof12mwithinamaximumof6s..轉(zhuǎn)向系統(tǒng)必須保證車輛容易地和安全地轉(zhuǎn)向：它要能夠盡可能的使前輪在最多6秒之內(nèi)轉(zhuǎn)動到轉(zhuǎn)彎半徑為12米的圓的相應位置。25.Thepurposeofthesuspensionsystemistopreventlargeshocks,causedbythewheelsstrikingbumpsintheroad,beingpassedtothevehicleoccupantsandcomponents;otherwisediscomfortanddamagewouldoccur.懸架目的是防止車輪撞擊路上障礙物時，傳到乘客和車輛組件的巨大震動。不然，不舒適感和危害將會出現(xiàn)。26.Thefrontsuspensionismorecomplicatedthantherearsuspension.Thisisbecausethefrontwheelsmustmoveinseveraldifferentdirections.Thewheelsmustmoveupanddownwiththesuspensionandtumlefttorightwiththesteering.前懸架比后懸架更加的復雜，這是因為前輪需要向幾個不同的方向移動。車輪必須隨著懸架上下移動，并且伴隨著轉(zhuǎn)向系統(tǒng)左右轉(zhuǎn)動。四．句子中譯英1汽車的主要組成部分包括車身、發(fā)動機、底盤和電氣設備。Themainpartsofthevehicleincludingengine,chassis,bodyandelectricalequipment.2底盤包括傳動系統(tǒng)，懸架，轉(zhuǎn)向部分以及制動系統(tǒng)Thechassisincludesthepowertrain,suspension,steeringandbrakingsystems.3如果發(fā)動機燃燒發(fā)生在汽缸內(nèi)，該氣缸稱為發(fā)動機內(nèi)燃機.Ifenginecombustionoccurswithinthepowerchamber,theengineiscalledaninternalcombustionengine.4活塞本身,它的環(huán)和活塞銷一起稱為活塞總成.Thepistonitself,itsringsandthepistonpinaretogethercalledthepistonassembly.5現(xiàn)代的汽油汽車的壓縮比大概為9：1.Moderngasolineenginehavecompressionratiosofabout9:1.6柴油汽車的壓縮比在18：1到22：1之間.Dieselcarengineshavecompressionratiosbetween18:1and22:1.7四沖程發(fā)動機的工作循環(huán)包括四個活塞行程Fourstrokeenginecycleconsistsoffourpistonstrokes.8柴油機稱為壓燃式發(fā)動機。Thedieseliscalledacompression-ignitionengine.9汽油機稱為點燃式發(fā)動機。Thegasolineiscalledaspark-ignitionengine.10有兩種類型的冷卻方式：空冷和液體冷卻。Therearetwomethodsofcooling:aircoolingandliquidcooling.11有兩種類型的變速器：手動和自動。Therearetwotypesoftransmissions-manual(MT)andautomatic(AT).12傳動軸將變速器主軸輸出的動力傳遞給主減速器的小齒輪。Thepropellershafttransmitsthedrivefromthetransmissionmainshafttothefinaldrivepinion.13當前使用的三種類型的制動系統(tǒng)：行車制動系統(tǒng)，駐車制動系統(tǒng)以及額外的緩速制動系統(tǒng)。Thethreetypesofbrakingsystemsareinusetoday:servicebrakingsystem,parkingbrakingsystemandadditionalretarding-brakingsystem.14現(xiàn)代轎車采用兩種類型的制動器：鼓式制動器和盤式制動器。Twotypesofbrakesareusedinmoderncars:drumbrakesanddiscbrakes.15.在制動時，防抱死制動系統(tǒng)能夠避免車輪抱死。ABScanpreventwheelsfromlockingupduringbraking.16大多數(shù)重型商用車采用循環(huán)球式轉(zhuǎn)向器。Mostheavycommercialvehiclesusetherecirculatingballtypeofsteeringgear.17現(xiàn)代轎車采用獨立前懸架。Moderncarsuseanindependentfrontsuspension.18后懸架的作用是支撐后部的重量。Thepurposeoftherearsuspensionistosupporttheweightoftherearofthevehicle.19.現(xiàn)代許多轎車采用發(fā)動機前置前驅(qū)布置方式。Manymoderncarshavefront-enginefront-drivelayouts.20在汽車懸架系統(tǒng)中，有三種基本類型的彈簧：螺旋彈簧，鋼板彈簧和扭桿彈簧。Therearethreebasictypesofspringsinautomobilesuspension–coilspringleafspringandtorsionbars.段落英譯中1.EngineOperatingPrinciplesMostautomobileenginesareinternalcombustion,reciprocating4-strokegasolineengines,butothertypeshavebeenused,includingthediesel,therotary(Wankel)the2-srtoke,andstratifiedcharge.

Reciprocatingmeansupanddownorbackandforth,itistheupanddownactionofapistoninthecylinderblock,orengineblock.Theblockisanironoraluminumcastingthatcontainsenginecylindersandpassagescalledwaterjacketsforcoolantcirculation.Thetopoftheblockiscoveredwiththecylinderheadwhichformsthecombustionchamber.Thebottomoftheblockiscoveredwithanoilpanoroilsump.

Powerisproducedbythelinearmotionofapistoninacylinder.However,thislinearmotionmustbechangedintorotarymotiontotumthewheelsofcars.Thepistonisattachedtothetopofaconnectingrodbyapin,calledapistonpinorwristpin.Thebottomoftheconnectingrodisattachedtothecrankshaft.Theconnectingrodtransmitstheup-and-downmotionofthepistontothecrankshaft,whichchangesitintorotarymotion.Theconnectingrodismountedonthecrankshaftwithlargebearingscalledrodbearings.Similarbearings,calledmainbearings,areusedtomountthecrankshaftintheblock.

Thediameterofthecylinderiscalledtheenginebore.Displacementandcompressionratioaretwofrequentlyusedenginespecifications.Displacementindicatesenginesize,andcompressionratiocomparesthetotalcylindervolumetocompressionchambervolume.

Thetermstrokeisusedtodescribethemovementofthepistonwithinthecylinder,aswellasthedistanceofpistontravel.Dependingonthetypeofenginetheoperatingcyclemayrequireeithertwoorfourstrokestocomplete.The4-strokeengineisalsocalledOttocycleengine,inhonoroftheGermanengineer,Otto,whofirstappliedtheprinciplein1876.Inthe4-strokeengine,fourstrokesofthepistoninthecylinderarerequiredtocompleteonefulloperatingcycle.Eachstrokeisnamedaftertheactionitperformsintake,compression,power,andexhaustinthatorder.l.IntakestrokeAsthepistonmovesdown,thevaporizedmixtureoffuelandairentersthecylinderthroughopenintakevalve.Toobtainthemaximumfillingofthecylindertheintakevalveopensabout10°beforeTDC,giving20°overlap.Theinletvalveremainsopenuntilsome50°afterBDCtotakeadvantageofincomingmixture2.CompressionstrokeThepistonturnsup,theintakevalvecloses,themixtureiscompressedwithinthecombustionchamber,whilethepressurerisetoaboutiMpa,dependingonvariousfactorsincludingthecompressionratio,throttleopeningandenginespeed.Nearthetopofthestrokethemixtureisignitedbyasparkwhichbridgesthegapofthesparkplug.3.PowerstrokeTheexpandinggasesofcombustionproducesariseinpressureofthegastosome3.5Mpaandthepistonisforceddowninthecylinder.Theexhaustvalveopensnearthebottomofthestroke.

4.ExhauststrokeThepistonmovesbackupwiththeexhaustvalveopensome50°beforeBDC,allowingthepressurewithinthecylindertofallandtoreduce"back"pressureonthepistonduringtheexhauststroke,andtheburnedgasesarepushedouttoprepareforthenextintakestroke.Theintakevalveusuallyopensjustbeforetheexhauststroke.This4-strokecycleiscontinuouslyrepeatedineveryaslongastheengineremainsrunning.

A2-strokeenginealsogoesthroughfouractionstocompleteoneoperatingcycle.However,theintakeandthecompressionactionsarecombinedinonestroke,andthepowerandexhaustactionsarecombinedintheotherstroke.Theterm2-strokecycleor2-strokeispreferredtotheterm2-cycle,whichisreallynotaccurate.Inautomobileengines,allpistonsareattachedtoasinglecrankshaft.Themorecylindersanenginehas,themorepowerstrokesproducedforeachrevolution.Thismeansthatan8-cylinderenginerunsmoresmoothlybecausethepowerstrokesareclosertogetherintimeandindegreesofenginerotation.

Thecylindersofmulti-cylinderautomotiveenginesarrangedinoneofthreeways.

1.Inlineenginesuseasingleblockofcylinder.Most4-cylinderandany6-cylinderenginesareofthisdesign.Thecylindersdonothavetobevertical.Theycanbeinclinedeitherside.

2.V-typeenginesusetwoequalbandsofcylinders,usuallyinclined60degreesor90degreesfromtheeachother.MostV-typeengineshave6or8cylinders,althoughV-4andV-12engineshavebeenbuilt.

3.Horizontallyopposedorpancakeengineshavetwoequalbanksofcylinders180degreesapart.Thesespacessavingenginedesignsareoftenair-cooled,andarefoundintheChevroletCarvair,Porsches,Subaus,andVolkswagens.Subaus

designisliquidcooled.Late-modelVolkswagenvansusealiquid-cooledversionoftheaircooledVWhorizontallyopposedengine.1.發(fā)動機工作原理大多數(shù)汽車的發(fā)動機是內(nèi)燃機，往復四沖程汽油機，但是也有使用其它類型的發(fā)動機，包括柴油機，轉(zhuǎn)子發(fā)動機，二沖程發(fā)動機和分程燃燒發(fā)動機。往復的意思就是上下運動或前后運動，在往復發(fā)動機中，氣缸中活塞的上下運動產(chǎn)生發(fā)動機的動力，這種類型幾乎所有的發(fā)動機都是依賴氣缸體即發(fā)動機缸體，缸體是鑄鐵或鑄鋁制的，它包括發(fā)動機氣缸和冷卻液循環(huán)用的水套。缸體的頂部是氣缸蓋，它組成了燃燒室，缸體底部是油底殼。氣缸內(nèi)活塞的直線運動產(chǎn)生動力，然而，必須將直線運動轉(zhuǎn)化成旋轉(zhuǎn)運動，使汽車車輪轉(zhuǎn)動，活塞銷將活塞連接在連桿頂部，連桿底部與曲軸連接，連桿將活塞的往復運動傳遞給曲軸，曲軸將其轉(zhuǎn)化為旋轉(zhuǎn)運動，連桿是用連桿曲軸安裝在曲軸上的，用類似的軸承即主軸承將曲軸固定在缸體內(nèi)。氣缸的直徑稱為發(fā)動機的內(nèi)徑，排量和壓縮比是兩個常用的發(fā)動機參數(shù)，排量是指發(fā)動機的大小，壓縮比是氣缸總?cè)莘e與燃燒室壓縮容積之比。術語沖程是用來說明活塞在氣缸內(nèi)的運動，也就是活塞行程的距離。根據(jù)發(fā)動機類型的需要二沖程或四沖程來完成一個工作循環(huán)四沖程發(fā)動機也叫做奧托發(fā)動機，為了紀念德國工程師奧托，他是在1876年第一個應用該原理的，在四沖程發(fā)動機中，要求氣缸活塞四沖程來完成一個完整的工作循環(huán)，每個沖程根據(jù)其行為命名分別為:進氣沖程，壓縮沖程，作功沖程和排氣沖程。1、進氣沖程當活塞下移時，霧化后的可燃混合氣通過打開的進氣門進入氣缸，為了達到最大的進氣量，進氣門在活塞到達上止點前10°打開，使進、排氣門有20°打開重疊角，進氣門一直打開到活塞到達下止點充分進入混合氣之后50°左右。2、壓縮沖程活塞開始向上移動時，進氣門關閉，混合氣在燃燒室中壓縮，根據(jù)不同因素包括壓縮比，節(jié)氣門開度，發(fā)動機轉(zhuǎn)速壓力上升到約1兆帕，接近沖程頂部時，火花塞產(chǎn)生的電火花擊穿點火間隙點燃可燃混合氣。3、作功沖程燃燒膨脹的氣體產(chǎn)生的壓力上升到3.5個兆帕時，推動活塞下移，接近氣缸底時，排氣門打開。4、排氣沖程隨著排氣門開啟約下止點前50°，活塞回升，使氣缸內(nèi)壓力下降在排氣沖程，減少對活塞回壓，派出廢氣，為下一個進氣沖程作準備，通常情況下，進氣門在排氣沖程完成前打開。只要發(fā)動機保持運轉(zhuǎn)，每個氣缸內(nèi)四個沖程循環(huán)連續(xù)不斷地重復下去。兩沖程發(fā)動機也同樣通過四行程來完成一個工作循環(huán)。但是進氣沖程，壓縮沖程合為一個沖程，作功沖程形成另一個沖程，術語兩行程循環(huán)和兩行程就是所謂的術語雙循環(huán)但實際上并不太準確。在所用的汽車發(fā)動機中，所有的活塞都是固定在一個曲軸上的，氣缸中發(fā)動機越多，每轉(zhuǎn)為發(fā)動機的作功沖程產(chǎn)生越多的動力，這就意味著八缸發(fā)動機運轉(zhuǎn)的越平順，因為發(fā)動機在作功沖程中運轉(zhuǎn)時間和旋轉(zhuǎn)角度緊密。多氣缸發(fā)動機有三種排列形式，任其一種:1、直列式發(fā)動機用一個氣缸體，大多數(shù)四缸發(fā)動機和一些六缸發(fā)動機都采用這種型式，這種氣缸不必垂直分布，它們可以向任一方向傾斜。2、V-型發(fā)動機用兩排同樣的氣缸，通常夾角為60°或90°，大多數(shù)有六缸或八缸，盡管四缸和十二缸也有采用V型的。3、臥式或者對置式發(fā)動機有兩排互為180°的氣缸，這些節(jié)省窨發(fā)動機設計通常采用風冷式，在雪弗蘭、富士、大眾車采用這種型式，富士汽車采用水冷式，在頂置式風冷發(fā)動機中，大眾的新型廂式汽車采用水冷式。Engine

Theengineactsasthepowerunit.Theinternalcombustionengineismostcommon:thisobtainsitspowerbyburningaliquidfuelinsidetheenginecylinder.Therearetwotypesofengine:gasoline(alsocalledaspark-ignitionengine)anddiesel(alsocalledacompression-ignitionengine).Bothenginesarecalledheatengines;theburningfuelgeneratesheatwhichcausesthegasinsidethecylindertoincreaseitspressureandsupplypowertorotateashaftconnectedtothepowertrain.

Thewayenginecylindersarearrangediscalledtheengineconfiguration.In-lineengineshavethecylindersinaline.Thisdesigncreatesasimplycastengineclock.Invehicleapplications,thenumberofcylindersisnormallyfrom2upto6.Usually,thecylindersarevertical.Asthenumberofthecylindersincreases,thelengthoftheblockandcrankshaftcanbecomeaproblem.OnewaytoavoidthisiswithaVconfiguration.Thisdesignmakestheengineblockandcrankshaftshorterandmorerigid.Anenginelocatedatthefrontcanbemountedlongitudinallyandcandriveeitherthefrontortherearwheels.Rearenginevehicleshavetheenginemountedbehindtherearwheels.Theenginecanbetransverseorlongitudinalandusuallydrivestherearwheelsonly.

Theengineblockisthebasicframeoftheengine.Allotherenginepartseitherfitinsideitorfastentoit.Itholdsthecylinders,waterjackets,andoilgalleries.Theengineblockalsoholdsthecrankshaft,whichfastenstothebottomoftheblock.Thecamshaftalsofitsinsidetheblock,exceptonoverhead-camengines(OHC).Inmostcars,thisblockismadeofgrayiron,oranalloy(mixture)ofgrayironandothermetals,suchasnickelorchromium.Engineblocksarecastings.

Someengineblocks,especiallythoseinsmallercars,aremadeofcastaluminum.Thismetalismuchlighterthaniron.However,ironwearsbetterthanaluminum.Therefore,thecylindersinmostaluminumenginesarelinedwithironorsteelsleeves.Thesesleevesarecalledcylindersleeves.Someengineblocksaremadeentirelyofaluminum.

Thecylinderheadfastenstothetopoftheblock,justasarooffitsoverahouse.Theundersideformsthecombustionchamberwiththetopofthepiston.Themostcommoncylinderheadtypesarethehemi,wedge,andsemi-hemi.Allthreeofthesetermsrefertotheshapeoftheengine'scombustionchamber.Thecylinderheadcarriesthevalves,valvespringsandtherockersontherockershaft,thispartofthevalvegearbeingworkedbythepush-rods.Sometimesthecamshaftisfitteddirectlyintothecylinderheadandoperatesonthevalveswithoutrockers.Thisiscalledanoverheadcamshaftarrangement.2．發(fā)動機發(fā)動機作為動力裝置。內(nèi)燃發(fā)動機最常用，它通過燃燒發(fā)動機氣缸里的液體燃料而獲得能量。內(nèi)燃機有兩種類型：汽