2.1EngineClassification2.2HowanEngineWorks2.3EngineComponents(1)2.4EngineFuelSystems2.5EngineCoolingSystems2.6engineLubricationSystemPARTⅡAUTOMOBILEENGINESPART?ⅡAUTOMOBILEENGINES學(xué)習(xí)目標(biāo)

通過本章的學(xué)習(xí)，你應(yīng)當(dāng)能夠：了解汽車發(fā)動機(jī)構(gòu)造的相關(guān)知識，掌握有關(guān)詞匯詞組。掌握汽車發(fā)動機(jī)相關(guān)術(shù)語的英語表達(dá)方法。能查閱與汽車知識有關(guān)的英文資料。能借助字典翻譯汽車構(gòu)造方面的文章。

Internalcombustiongasolineengines(SeeFig.2.0.1)runonamixtureofgasolineandair.

Theidealmixtureis14.7partsofairtoonepartofgasoline(byweight.)

Sincegasweighsmuchmorethanair,wearetalkingaboutawholelotofairandatinybitofgas.Onepartofgasthatiscompletelyvaporizedinto14.7partsofaircanproducetremendouspowerwhenignitedinsideanengine.

Let’sseehowthemodernengineusesthatenergytomakethewheelsturn.

Fig.2.0.1

Internalcombustiongasolineengines

Airenterstheenginethroughtheaircleanerandproceedstothethrottleplate.Youcontroltheamountofairthatpassesthroughthethrottleplateandintotheenginewiththegaspedal.

Itisthendistributedthroughaseriesofpassagescalledtheintakemanifold,toeachcylinder.

Atsomepointaftertheaircleaner,dependingontheengine,fuelisaddedtotheair-streambyeitherafuelinjectionsystemor,inoldervehicles,bythecarburetor.

Themajorityofenginesinmotorvehiclestodayarefour-stroke,spark-ignitioninternalcombustionengines.

2.1EngineClassification

Theenginescanbeclassifiedinthefollowingseveralways:(1)operatingcycle,(2)pistonaction,(3)pistonconnection,(4)cylinderarrangement,(5)methodoffuelinjection,and(6)speed.

(1)Operatingcycle

Dieselandgas-burningenginescanbedividedintotwogroupsbasedonthenumberofpistonstrokespercycle,eitherfourortwo.Anenginewhichneedsfourstrokestocompleteonecycleisafour-strokecycleengineor,forshort,afour-cycleengine.Ifitneedsonlytwostrokestocompleteacycle,itiscalledatwo-strokecycleengineor,forshort,atwo-cycleengine.Thus,atwo-cycleenginefirestwiceasoftenasafour-cycleengine.

(2)Pistonaction

Anengine’spistonactionmaybeclassifiedas(a)single-action,(b)double-action,or(c)opposed-piston.

Single-actingenginesuseonlyoneendofthecylinderandonefaceofthepistontodeveloppower.Thisworkingspaceisattheendawayfromthecrankshaft,thatis,attheupperendofaverticalengine.

Double-actingenginesusebothendsofthecylinderandbothfacesofthepistontodeveloppowerontheupstrokeaswellasonthedownstroke.Theconstructioniscomplicated;therefore,double-actingenginesarebuiltonlyinlargeandcomparativelylow-speedunits,generallytopowermotorships.

Anopposed-pistonenginehascylindersineachofwhichtwopistonstravelinoppositedirections.Thecombustionspaceisinthemiddleofthecylinderbetweenthepistons.Therearetwocrankshafts：theupperpistonsdriveone,thelowerpistonstheother.Notethateachpistonissingle-acting;thatis,itdevelopspowerwithonlyonefaceofthepiston.

(3)pistonconnection

Thepistonmaybeconnectedtotheupperendoftheconnectingrodeitherdirectly(“trunkpiston”type),orindirectly(“crosshead”type).

Intrunk-pistonengines,ahorizontalpinwithinthepistonisencircledbytheupperendoftheconnectingrod.Thisbyfarthemostcommonconstruction.

Incrosshead-typeengines,thepistonfastenstoaverticalpistonrodwhoselowerendisattachedtoaslidingmembercalleda“crosshead”,whichslidesupandowninguides.Thecrossheadcarriesacrossheadpinwhichisencircledbytheupperendoftheconnectingrod.Thismorecomplicatedconstructionisrequiredindouble-actingengines.Itisalsousedinsomelarge,slow-speed,single-actingengines.

(4)Cylinderarrangement?(SeeFig.2.1.1)

Thefourbasiccylinderarrangementsofadieselorgas-burningengineare:(a)cylinder-in-line,(b)v-arrangement,(c)flat,and(d)radial.Fig.2.1.1Typicalcylinderarrangements

Acylinder-in-linearrangement.Thisisthesimplestandmostcommonarrangement,withallcylindersarrangedverticallyinline.Thisconstructionisusedforengineshavingupto12cylinders.Enginesarealsobuiltwithhorizontalcylinders,usuallyoneortwo,inafewcaseswiththreecylinders.

Ifanenginehasmorethaneightcylinders,itbecomesdifficulttomakeasufficientlyrigidframeandcrankshaftwithanin-linearrangement.Also,theenginebecomesquitelongandtakesupconsiderablespace.Thev-arrangement,withtwoconnectingrodsattachedtoeachcrankpin,permitsreducingtheenginelengthbyalmostone-half,thusmakingitmuchmorerigid,withastiffcrankshaft.Italsocostslesstomanufactureandinstall.Thisisacommonarrangementforengineswitheight,twelve,andsixteencylinders.Cylinderslyinginonelinearecalleda“bank”,andtheanglebetweenthebanksmayvary,inmanufacturingpractice,from30°to120°,themostcommonanglesbeingbetween40°and75°.?(Acompletecircleis360°)

Aflatengineisav-enginewiththeanglebetweenthebanksincreasedto180°.Thisarrangementisusedwherethereislittleheadroom,asintrucks,buses,andrailcars.Flatenginesarealsocalled“opposed-cylin-der”engines.

Inaradialengineallthecylindersaresetinacircleandallpointtowardthecenterofthecircle.Theconnectingrodsofallthepistonsworkonasinglecrankpin,whichrotatesaroundthecenterofthecircle.Sucharadialengineoccupieslittlefloorspace.Byattachingtheconnectingrodstoamasterdisksurroundingthecrankpin,asmanyastwelvecylindershavebeenmadetoworkonasinglecrankpin.

(5)Methodoffuelinjection

Dieselenginesaredividedintoair-injectionenginesandsolidormechanicalinjectionengines.Air-injectionenginesuseablastofhighlycompressedairtoblowthefuelintothecylinder.Airinjectionwascommonlyuseonearlydieselenginesbutwiththedevelopmentofsolid-injectionsystemstheair-injectionengineisrapidlydisappearing.

(6)Speed

Alldieselandgas-burningenginesmaybedividedintothreeclassesaccordingtospeed;low-speed,medium-speed,andhigh-speedengines.Automotivedieselenginesoftenrunfasterthan1,200rpm,butthegreatmajorityofotherenginesrunbetween350and1,200rpmandaretermedmedium-speedengines.TechnicalWordscomplete vt. 完成，結(jié)束

single-acting adj. 單動的，單作用的

develop v. 發(fā)展，發(fā)出，產(chǎn)生

crankshaft n. 曲軸，曲柄軸

vertical adj. 垂直的，直立的

upstroke n. (活塞)上行程

downstroke n. (活塞)下行程complicated adj.復(fù)雜的，結(jié)構(gòu)復(fù)雜的motorship n. 內(nèi)燃機(jī)船，汽船crosshead n. 十字頭，滑塊horizontal adj. 水平的，臥式的，地平的encircle vt. 環(huán)繞，包圍，圍繞considerable adj. 相當(dāng)大(多)的crankpinn.曲柄銷，曲軸(拐軸)銷manufacture v.；n. 制造，生產(chǎn)，加工；制造， 生產(chǎn)，加工bank n. 一排，組，機(jī)組rigid adj. 剛性的，剛硬的，不易彎的stiff adj. 剛性的，堅(jiān)硬的，非彈性的vary vt. 變化，使多樣化，改變rotate vt. 旋轉(zhuǎn)，轉(zhuǎn)動，使旋轉(zhuǎn)occupy vt. 占有，占據(jù)，擁有blast n. 一陣，一股，氣流medium adj. 中間的，中等的，適中的PhrasesandExpressions

fuelinjection 燃油噴射

divideinto… 分成……，分為……

bebasedon… 以……為基礎(chǔ)，根據(jù)……

pistonstroke 活塞行程，沖程

forshort 簡稱，為簡略起見

(be)awayfrom 離開……，遠(yuǎn)離，不在……處trunk-pistonengine 筒狀活塞式發(fā)動機(jī)byfar (用以修飾比較級，最高級) 最……，……得多gas-burningengine 汽油(發(fā)動)機(jī)，可燃?xì)怏w發(fā)動機(jī)cylinder-in-line 直列式氣缸asufficientlyrigidframe 足夠剛性的機(jī)架radialengine 徑向式發(fā)動機(jī)，星形發(fā)動機(jī)asmanyas 多達(dá)……，達(dá)……之多thegreatmajorityof 大部分……，大多數(shù)……NotesontheText

1．Anopposed-pistonenginehascylindersineachofwhichtwopistonstravelinoppositedirections.對置式發(fā)動機(jī)的每個氣缸中都有兩個活塞沿相反方向運(yùn)動。

2．Therearetwocrankshafts：theupperpistonsdriveone,thelowerpistonstheother.有兩根曲軸：上面的活塞驅(qū)動一根，下面的活塞驅(qū)動另一根。

3．Incrosshead-typeengines,thepistonfastenstoaverticalpistonrodwhoselowerendisattachedtoaslidingmembercalleda“crosshead”,whichslidesupanddowninguides.在十字頭型發(fā)動機(jī)中，活塞連接在一根垂直的活塞桿上，活塞桿的下端又連接在一個叫做“十字頭”的滑動構(gòu)件上，十字頭在導(dǎo)軌中上下滑動。

4．Thev-arrangement,withtwoconnectingrodsattachedtoeachcrankpin,permitsreducingtheenginelengthbyalmostone-half,thusmakingitmuchmorerigid,withastiffcrankshaft.

V形排列，由于每個曲柄銷上有兩根連桿，所以可使發(fā)動機(jī)的長度幾乎縮短一半，這樣就使發(fā)動機(jī)的剛性更大，曲軸也更堅(jiān)固。

5．Thisarrangementisusedwherethereisalittleheadroomasintrucks,buses,andrailcars.這種氣缸排列通常用在頭部空間很小的機(jī)動車上，如貨車、公共汽車以及有軌電車上。

6．Byattachingtheconnectingrodstomasterdisksurroundingthecrankpin,asmanyastwelvecylindershavebeenmadetoworkonasinglecrankpin.通過把連桿連接到包住曲柄銷的一個主盤上，十二個氣缸便可在同一個曲柄銷上工作。Exercises

Ⅰ.?PutthefollowingexpressionsintoChinese.

1．burnitsfuelwithintheengineproper

2．a(chǎn)sparktoignitethefuel

3．piston-typeinternalcombustionengines

4．a(chǎn)ir-cooledengine

5．singlecylinderdieselengine

6．multicylinderengine

7．connecttotheupperendoftheconnectingrod

8．sparkignitionengine

9．four-stroke-cycledieselengine

10．horizontalopposedcylinderdieselengine

Ⅱ.?Completingthesentences:Thesentencesbelowareincomplete.Aftereachsentence

therearefourwordsorphrases,onlyoneofwhichwillcorrectlycompletethesentence,selectingtheproperwordorphrasetocompleteitcorrectly.

1．Incarburetorengines,theair/fuelmixtureis＿＿byaspark.

A.developedB.producedC.ignitedD.blownout

2．Theconnectingrodisattachedtothepistonbythe____.??A.rodcapB.pistonpinC.capboltsD.capbearing

3．Thefourstrokesintheengineare,inorderofoccurrence:____.??A.intake,power,exhaust,andcompression??B.intake,exhaust,power,andcompression??C.intake,compression,power,andexhaust??D.intake,power,compression,andexhaust

4．Enginescanbedividedinto____bythenumberofpistonstrokesinonecompletecycle.??A.twogroupsB.threekindsC.fourclassesD.six

5．Accordingtothemethodofignitionoftheairfuelmixture,enginesaredividedinto____.??A.gasengineandsteamengine??B.gasolineengineanddieseslengine??C.externalcombustionengineandcompressionignitionengine??D.internalcombustionengineanddieselengine

6．Inthestandardengine,eachcylinderhas____.A.onevalveB.twovalvesC.threevalvesD.fourvalves

Ⅲ.?TranslatethefollowingsentencesintoChinese.

1．Ifthepistonismovedupanddowninthecylinder,thisup-and-down,orreciprocating,motionofthepistonischangedintotherotarymotionofthecrankshaftbytheconnectingrodandthecrankoftheshaft.

2．Theadvantageofthedieselisitsgreaterpullingor“l(fā)ugging”powerwhenitslowsdownunderaheavyload,inotherwords,thedieselloseslesspoweratreducedspeedthanthegasolineengine.

3．Additionaladvantagesofthedieselenterintocertainspecialapplicationssuchasisolatedservicestations,railwaywaterstations,vacationresorts,lumbercamps,minepowerplants,oil-welldrilling,andemergencypowerplants.

4．Thefundamentaldifferencebetweenpetrolanddieselenginesisthatinthepetrolthesourceofheatforignitingthecharge,namely,anelectricspark,isgeneratedoutsidetheengine,andistaken,asitwere,intothewaitingchargeattherequiredinstant.

5．Atanearlystageintheevolutionofthehighspeeddieselengineavariabletimingdevicewasintroducedinthepumpdrivecoupling,takingtheformofahelicallysplinedsleevebymeansofwhichtheangularrelationbetweendrivinganddrivenshaftscouldbevariedbymanualorautomaticcontrol.ReadingMaterialEnginemaintenance

Asoundengineshoulddevelopfullpower,runsteadilyunderfull-loadandno-loadconditions,withoutoverheating,smoking,oilorcoolantleakage.Sometroublescanbeidentifiedbytheirsymptomswithoutdisassemblingtheengine.

Thesymptomsindicativeofsometroubleswiththecrankgearincludeforeignnoiseandknocks,lossofpower,excessiveoilandfuelconsumption,smokyexhaust.

Noiseandknocksintheenginearecausedbythewearofitsbasicpartsleadingtoexcessiveclearancebetweenitsmatingparts.

Ifthepistonandcylinderarewornandtheclearancebetweenthemisexcessive,aclearmetallicknockingappears,whichismostvividwhentheenginerunscold.Asharpmetallicknockingatallspeedsindicatesanincreasedclearancebetweenthepistonpinandtheconnectingrodbush.Iftheknockinggrowswhentheengineissharplythrottledup,themainorcrankpinbearingshellsareworn,thedullerknockssymptomizingthewearofthemainbearings.Sharpcontinuousknockingintheengineaccompaniedbytheoilpressuredropisanevidenceofmeltingoutofbearings.Theengineknockscanbelistenedtowiththeuseofstethoscope.

Lossofenginepowerstemsfromthedropofcompressionwhichmayoccurwhenthecylinderblockheadnutsaretightenednonuniformlyorinsufficiently,ortheheadgasketisdamaged,thepistonringsarestuckinthegroovesowingtocarbonorlacquerdeposit;theringsareworn,brokenorlosttheirresilience;thecylindersareworn.

Thecompressioncanbecheckedwithacompressiongaugeorbyhand.Tocheckthecompressionbyhand,driveoutthesparkplugsfromallthecylindersbuttheonebeingchecked.Whilerotatingthecrank,estimatethecompressionbytheresistancetotherotation.Thecompressioninothercylindersischeckedinasimilarway.

Tocheckthecompressionwithacompressiongauge,warmuptheengine,driveoutthesparkplugs,fullyopenthethrottleandchokevalves.Installarubbernippleofthecompressiongaugeintotheplughole,turnthecrankshaft8or10timesandcheckthegaugereading.Afterthecrankshaftisturned,thepressureinthegoodcylindershouldbe7.0~7.8kgf/cm2(0.7～0.78MPa).Thisprocedureshouldbeusedtocheckthecompressionconsecutivelyinallthecylindersoftheengine.

Excessivefuelandoilconsumptionandsmokygrayexhaust(theoillevelinthecrankcasebeingnormal)areusuallyattributedtothestickingorwearofthepistonrings.Stickingcanberemediedwithoutdisassemblingtheengine;forthispurpose,mixequalpartsofdenaturedalcoholandkeroseneandpour20gofthemixtureintoeachcylinderthroughthesparkplughole,leavingitthereovernight.Inthemorningstarttheengine,runitfor10to15minutes,shutdownandchangetheoil.

Carbonizationoftheengine,i.e.depositionofcarbononthepistoncrownsandcombustionchambers,impairsheattransferandleadstooverheating,lossofpowerandexcessivefuelconsumption.Toremovethecarbondeposit,drainthecoolant,removetheunitsmountedonthecylinderhead,undothenutsanddetachthecylinderheadcarefullysoasnottodamagethegasket.Ifthegaskethasstucktotheheadorblock,separateitwithabluntknifeorawideandthinstripofmetal.

Removethecarbondepositwithscrapersmadeofwoodorsoftmetaltoavoiddamagingthepistoncrownsorcombustionchamberwalls.Insodoing,covertheadjacentcylinderswithcleanrags.Thecarbondepositgoesoffeasieraftersofteningbyapplyingkerosene-soakedrags.

Wheninstallingthecylinderblockheadgasket,wipeitwithpowderedgraphite.

Cracksinthewallsofthecylinderblockandheadmayresultfromfreezingofwaterorfillingcoldwaterintoahotengine.

Themaintroublescharacteristicofthevalvegearareimproperseatingorincompleteopeningofthevalves.

Improperseatingissymptomizedbypoorcompression,poppingintheinletandexhaustmanifolds,lossofpower.Improperseatingmaybecausedbycarbondepositonthevalvesintheguides,absenceofclearancebetweenthevalvestemandtherocker.

Incompleteopeningofthevalvesischaracterizedbyknockingintheengineandlossofpower.Thisderangementstemsfromexcessiveclearancebetweenthevalvestemandtherocker.

Thevalvegeartroublesalsoincludewearofthecrankshaftgears,tappets,guides,excessiveendplayofthecamshaft,wearofrockerbushingsandfulcrums.

Toadjusttheclearancebetweenthevalvestemandtherocker,removethevalvecover,firstdetachingallthepartsmountedonit;shiftthepistontoTDConthecompressionstrokesothatthevalvesareclosed;checktheclearanceandadjustit,ifnecessary,asfollows:undothelock-nutontherockeradjustingscrew,settherequiredclearancebyrotatingtheadjustingscrew,tightenthelock-nutholdingthescrewwiththescrewdriverandrechecktheclearance.PhrasesandExpressions

beidentifiedby 用……來確定，用……來作標(biāo)志

beindicativeof 表現(xiàn)出，有……征兆，有……的征兆

smokyexhaust 有煙排氣

matingparts 配合件，相配構(gòu)件，配件

connectingrodbush 連桿軸套

crankpinbearingshells 曲柄銷軸瓦(軸承殼套)withtheuseofstethoscope 利用聽診器stemfrom 由……引起，產(chǎn)生于……rubbernipple 橡膠接頭，橡皮套(be)attributedto 起因于，被認(rèn)為是……所造成的denaturedalcohol 變性酒精impairheattransfer 減弱傳熱becharacterizedby ……的特點(diǎn)在于，在……上有 明顯區(qū)別rockeradjustingscrew 搖臂調(diào)整螺釘2.2HowanEngineWorks

Sincethesameprocessoccursineachcylinder,wewilltakealookatonecylindertoseehowthefourstrokeprocessworks.

ThefourstrokesareIntake,Compression,PowerandExhaust.ThepistontravelsdownontheIntakestroke,upontheCompressionstroke,downonthePowerstrokeandupontheExhauststroke.??Intake?(SeeFig.2.2.1)

AsthepistonstartsdownontheIntakestroke,theintakevalveopensandthefuel-airmixtureisdrawnintothecylinder(similartodrawingbacktheplungeronahypodermicneedletoallowfluidtobedrawnintothechamber).

Whenthepistonreachesthebottomoftheintakestroke,theintakevalvecloses,trappingtheair-fuelmixtureinthecylinder.?Fig.2.2.1iNTAKE

??Compression

Thepistonmovesupandcompressesthetrappedairfuelmixturethatwasbroughtinbytheintakestroke.Theamountthatthemixtureiscompressedisdeterminedbythecompressionratiooftheengine.Thecompressionratioontheaverageengineisintherangeof8∶1to10∶1.

Thismeansthatwhenthepistonreachesthetopofthecylinder,theair-fuelmixtureissqueezedtoaboutonetenthofitsoriginalvolume.

??Power

Thesparkplugfires,ignitingthecompressedair-fuelmixturewhichproducesapowerfulexpansionofthevapor.Thecombustionprocesspushesthepistondownthecylinderwithgreatforceturningthecrankshafttoprovidethepowertopropelthevehicle.Eachpistonfiresatadifferenttime,determinedbytheenginefiringorder.Bythetimethecrankshaftcompletestworevolutions,eachcylinderintheenginewillhavegonethroughonepowerstroke.

??Exhaust

Withthepistonatthebottomofthecylinder,theexhaustvalveopenstoallowtheburnedexhaustgastobeexpelledtotheexhaustsystem.Sincethecylindercontainssomuchpressure,whenthevalveopens,thegasisexpelledwithaviolentforce(thatiswhyavehiclewithoutamufflersoundssoloud.)Thepistontravelsuptothetopofthecylinderpushingalltheexhaustoutbeforeclosingtheexhaustvalveinpreparationforstartingthefourstrokeprocessoveragain.

OilingSystem

Oilisthelife-bloodoftheengine.Anenginerunningwithoutoilwilllastaboutaslongasahumanwithoutblood.Oilispumpedunderpressuretoallthemovingpartsoftheenginebyanoilpump.Theoilpumpismountedatthebottomoftheengineintheoilpanandisconnectedbyageartoeitherthecrankshaftorthecamshaft.

Thisway,whentheengineisturning,theoilpumpispumping.Thereisanoilpressuresensorneartheoilpumpthatmonitorspressureandsendsthisinformationtoawarninglightoragaugeonthedashboard.Whenyouturntheignitionkeyon,butbeforeyoustartthecar,theoillightshouldlight,indicatingthatthereisnooilpressureyet,butalsolettingyouknowthatthewarningsystemisworking.Assoonasyoustartcrankingtheenginetostartit,thelightshouldgooutindicatingthatthereisoilpressure.

EngineCooling

Internalcombustionenginesmustmaintainastableoperatingtemperature,nottoohotandnottoocold.Withthemassiveamountsofheatthatisgeneratedfromthecombustionprocess,iftheenginedidnothaveamethodforcoolingitself,itwouldquicklyself-destruct.Majorenginepartscanwarpcausingoilandwaterleaksandtheoilwillboilandbecomeuseless.

Whilesomeenginesareair-cooled,thevastmajorityofenginesareliquidcooled.Thewaterpumpcirculatescoolantthroughouttheengine,hittingthehotareasaroundthecylindersandheadsandthensendsthehotcoolanttotheradiatortobecooledoff.TechnicalWords

compression n. 壓縮

plunger n. 柱塞，活塞

hypodermic n. 皮下注射器

muffler n. 消聲器，消音器

mount v. 使……固定

self-destruct v. 自我毀壞

warp v. (使某物)彎曲

coolant n. 冷卻器

radiator n. 散熱器

smother v. 覆蓋

vibration n. 振動

flywheel n. 飛輪

torque n. 扭轉(zhuǎn)力

converter n. 變流器，液力變距器

inertia n. 慣性

inherent adj. 內(nèi)在的，固定的

parallel v. 平行

spin v. 旋轉(zhuǎn)

offset v. 補(bǔ)償或抵消PhrasesandExpressions

bedrawninto 被卷入

theratioof ……的比例

besqueezedto 擠入

beexpelledto 驅(qū)逐

aslongas 只要

beattachedto 系、縛在

smoothout 使某物光滑、平坦NotesontheText

1．AsthepistonstartsdownontheIntakestroke,theintakevalveopensandthefuel-airmixtureisdrawnintothecylinder(similartodrawingbacktheplungeronahypodermicneedletoallowfluidtobedrawnintothechamber.)在進(jìn)氣行程，當(dāng)活塞開始下行時，進(jìn)氣門打開，空氣燃油的混合氣被吸入氣缸(類似于拉開注射器的柱塞，將液體吸到針管內(nèi))。

2．Bythetimethecrankshaftcompletestworevolutions,eachcylinderintheenginewillhavegonethroughonepowerstroke.曲軸轉(zhuǎn)兩周，發(fā)動機(jī)里的氣缸完成一個作功行程。

3．Whenyouturntheignitionkeyon,butbeforeyoustartthecar,theoillightshouldlight,indicatingthatthereisnooilpressureyet,butalsolettingyouknowthatthewarningsystemisworking.當(dāng)你打開點(diǎn)火開關(guān)，在啟動車子之前油量警示燈亮，表明此時無油壓力，同時也讓你知道報(bào)警系統(tǒng)已開始工作。

4．Thewaterpumpcirculatescoolantthroughouttheengine,hittingthehotareasaroundthecylindersandheadsandthensendsthehotcoolanttotheradiatortobecooledoff.水泵使冷卻液在整個發(fā)動機(jī)形成循環(huán)，冷卻液流至氣缸和氣缸蓋周圍發(fā)熱的區(qū)域，然后水泵把熱的冷卻液抽到散熱器中使之冷卻下來。Exercises

Ⅰ.AnswerthefollowingquestionsinEnglish.

1．Pleasetelltheprincipleofthecompressionstroke.

2．What’sthefunctionofamuffler?

3．Whydoestheoilpumpneedanoilpressuresensor?

4．Whathappenedtotheengineifitdidnothaveamethodforcoolingitself?

5．Howmanykindsofenginecooling?

6．Whydoengineersuseoneormorebalanceshafts?

Ⅱ.TranslatefollowingexpressionsintoEnglish.

1．壓縮比

2．進(jìn)氣、壓縮、作功、排氣行程

3．發(fā)動機(jī)點(diǎn)火順序

4．油壓傳感器

5．點(diǎn)火開關(guān)

6．廢氣排出

Ⅲ.TranslatethefollowingsentencesintoEnglish.

1．當(dāng)活塞到達(dá)進(jìn)氣行程的下止點(diǎn)時，空氣燃油混合氣進(jìn)入氣缸，進(jìn)氣門關(guān)閉。

2．每個活塞按不同的點(diǎn)火順序依次點(diǎn)火。

3．機(jī)油靠油泵的作用加壓流至發(fā)動機(jī)的各個部件。

4．發(fā)動機(jī)必須保持一個相對穩(wěn)定的工作溫度，既不太熱也不太冷。

Ⅳ.Pleaseselecttherightwordinthefollowingblockstocompletetheparagraph.

last

pump

mountconnectmonitorsendAnenginerunningwithoutoilwill

aboutaslongasahumanwithoutblood.Oilis

underpressuretoallthemovingpartsoftheenginebyanoilpump.Theoilpumpis

atthebottomoftheengineintheoilpanandis

byageartoeitherthecrankshaftorthecamshaft.Thisway,whentheengineisturning,theoilpumpispumping.Thereisanoilpressuresensorneartheoilpumpthat

pressureand

thisinformationtoawarninglightoragaugeonthedashboard.

Ⅴ.Completethesentences:Thesentencesbelowareincomplete.Aftereachsentencetherearefourwordsorphrases,onlyoneofwhichwillcorrectlycompletethesentence,selectingtheproperwordorphrasetocompleteitcorrectly.

1．Thefour-strokecycleoperatesinwhichorder

.

A.intake,compression,power,exhaust

B.compression,power,intake,exhaust

C.intake,exhaust,power,compression

D.intake,power,exhaust,compression

2．Thecombustionprocesspushesthepistondownthecylinderwithgreatforceturningthecrankshafttoprovidethepowerto

thevehicle.??A.expel

B.enforce C.propel

D.add

3．Withthe_________atthebottomofthecylinder,theexhaustvalveopenstoallowtheburnedexhaustgastobeexpelledtotheexhaustsystem.??A.piston

B.valve

C.camshaft D.crankshaft

4．Thereisan

neartheoilpumpthatmonitorspressureandsendsthisinformationtoawarninglightoragaugeonthedashboard.??A.oilpressuresensor

B.oxygensensor??C.temperaturesensor

D.speedsensor5．Theflywheeluses

tosmoothoutthenormalenginepulses.??A.pressure

B.inertia

C.throttle

D.carburetor

6．Abalanceshaftisaheavyshaftthatrunsthroughtheengine

thecrankshaft.??A.oppositeto

B.subjectto C.upto

D.paralleltoReadingMaterial

Don’tLetTheCarEngineIdle!

OLYMPIA－Here’sapowerfultooljustaboutanydrivercanusetosavemoneyandhelpprotecttheairwebreathe:theignitionswitch.

Idlingyourcarformorethan30secondswastesmoneyanddamagestheenvironment.Turningitoffisasimpleactthatcanmakeabigdifference.“Wedon’tusuallythinkabouthowidlingourcarscausespollution,”saidMaryBurg,whomanagestheairqualityprogramattheDepartmentofEcology(Ecology).“Weletourenginesrunatdrive-upwindows,whenwe’resittingatthemall,whenwe’rewaitingfortrainsorferries,whenwe’relisteningtotheradio.Weevenidleatschools,wherechildrenhavetobreathetheexhaust.”

Childrenbreathe50percentmoreairperpoundofbodyweightthanadults,andvehicleexhaustincreasesmanychildren’sasthmasymptoms.Morethanoneoutofevery10childreninWashingtonhasbeendiagnosedwithasthmaandthenumberisrising–it’sanepidemic.

Contrarytopopularbelief,idlingisn’taneffectivewaytowarmupmostcarengines.Today’sautomobilemanufacturersrecommenddrivingoffrightawayandurgethatdriverswaitnomorethan30secondstobegindriving,evenonthecoldestdays.

Somepeopleworrythatrestartingtheenginemightharmthecar,butfrequentrestartingdoeslittledamage.ResearchersinCanadafoundthatcomponentwearcausedbyfrequentrestartsaddsabout$10peryeartothecostofdriving,