發(fā)動(dòng)機(jī)英文翻譯

“中南林業(yè)科技大學(xué)”熱能與動(dòng)力工程專(zhuān)業(yè)“不落的星塵”全力打造，華麗的一個(gè)金幣，傳說(shuō)中的物美價(jià)廉發(fā)動(dòng)機(jī)英文翻譯、內(nèi)燃機(jī)英文翻譯、汽車(chē)英文翻譯、熱動(dòng)英文翻譯由于上傳失敗，現(xiàn)將兩幅插圖放在另一個(gè)文檔中期待各位的指正，謝謝！分割線割了煩惱畢業(yè)愉快工作愉快……(本文來(lái)自《汽車(chē)專(zhuān)業(yè)英語(yǔ)》/陳勇、邊明遠(yuǎn)主編)).TheEngine’sSstemTheengineisanimportantpartoftheautomobile;itactsastheheartofaperson,whichprovidesthepowerthatthecarsneedtorunontheroad.AlltheautomotiveenginestodayaretheInternalCombustionEngines(ICEs)becausethefuelisburntinsidetheircylindersandtheenergyisprovided.ICEsarethoseheatenginesthatburntheirfuelinsidetheenginecylinder.InICEs,thechemicalenergystoredintheirfuelconvertedintoheatenergyduringtheburningpartoftheiroperation.Theheatenergyisconvertedintomechanicalenergybytheexpansionofgasesagainstthepistonattachedtocrankshaftthatcanrotate.Theenginesthatburnpetrolareknownaspetrolengine.OthertypesofICEsburnheavieroils,ofthesetypesthedieselenginehascomeintothewidestuse.Dieselandpetrolengineshavethesamemechanicalparts,exceptthatdieselcomponentsaregenerallystrongerandheavier.Bothenginesareinternalcombustionengines,buttheyhavedifferentfuelsystemandusedifferentfuels.Withadiesel,onlyairentersthecylinderduringtheintakestroke.Apetrolenginetakesinanair-fuelmixture.Followingaresomegeneralcomparisonsbetweendieselandpetrolengines:Inadiesel,thefuelisinjectedintothecylinderasafinespraynearthetopofthecompressionstroke.Withapetrolengine,thefuelisinjectedintotheexhaustportsatthestartoftheinductionstroke.Ignitioninadieselisbythehightemperaturefromthehighlycompressedair.Apetrolengineneedsasparkforignition.Dieselenginesgenerallyoperateatlowerenginerpmthanpetrolengines.Dieselenginesusedistillateforfuel,whichislessvolatilethanpetrol.Thedesignofdieselenginesmakesthemnoisierthanpetrolenginesandtheyhaveauniquedieselknock.Smalldieselengines,aswellaspetrolengines,areusedinpassengercarsandlightcommercialvehicles.Largerdieselenginesareusedinallheavycommercialvehicles,earthmovingequipment,andfarmmachinery..EngineConfigurationsThetermengineconfigurationreferstothewaythatthecylindersofanenginearearranged.Thecylinderscanbein-line,oratanangle(V-type).Withinthesethreebasicarrangements,thereareanumberofvariations.In-lineengineWithin-lineengines,thecylindersarearrangedinastraightline,onebehindtheother.Mostin-lineengineshavetheircylindersvertical,butsomeareslanted.Thatis,theengineistiltedatanangletoreducetheoverallheight.Theseenginesaresometimesreferredtoasslantedengines.Somein-lineengineshavetheircylindershorizontal,sothattheengineismoreorlessonitsside.Thisreducestheoverallheightoftheengine.Thisarrangementis＜插圖位置〉usedmainlyinlargercommercialvehicleswiththeenginemountedunderpartofthecab.Themechanicalarrangementofafour-cylinderin-lineforapassengercarisshowninFig.1-9.Thecut-awayviewinFig.1-10enablesthevariouspartstobeidentified.HorizontallyopposedengineThisarrangementhasitscylindersarrangedintwoflatblankswiththecrankshaftbetweenthem.Theengineshownhasashortrigidcrankshaftwithfivebearings.Ahorizontallyopposedenginehasevenfiringimpulsesandgoodbalance.Movementofapistonindirectionisopposedbymovementofapistonintheoppositedirection.Horizontallyopposedengines,withtheirflatdesign,givetheenginealowheightandalsohelptokeepthecenterofgravityofthevehiclelow.Alowcenterofgravitygivesthevehiclestability.V-typeenginesWithV-typeengines,thecylindersarearrangedintwoblanksatanangle.Thisreducesthelengthoftheengineandmakesitmorecompact.Thisalsoreducesthelengthofthecrankshaft,whichcanbedesignedtobemorerigidthanalongshaft..TheEngineAssemblyandComponentsThecompleteengineassemblyconsistsofthemechanicalcomponentsthatmakeuptheengineitselfandalsoanumberofassociatedsystems.Thesearethesystemsthatareneededtostarttheengineandalsotocontrolitandkeepitrunning.Themechanicalpartsoftheengineassemblycanbebrokendownintoanumberofsub-assemblies,orgroupsofassociatedcomponents,althoughtheseareusuallyreferredtomerelyasassemblies,forexample,cylinder-headassemblyandpistonassembly.Somepartsofanengineareinternal,otherpartsareexternal,thisillustrationidentifiesanumberofexternalparts.Thevariouscomponentsofanengineareassembledtogetherduringmanufacturedandmostofthesearesecuredbymeansofbolts,nutsandothertypesoffasteners.Somepartsareinternalandothersareattachedtotheoutsideoftheengine.Thecylinderblockisthelargestpartofengine.Theotherpartsareeitherfittedintotheblockorattachedtoit.Asitsnamesuggests,itisbasicallyablockofcastmetal,usuallycastiron,butitcanbealuminumalloywithcastironorsteelliners.Aluminumisusedtoreducetheweight.Thecylinderblockhasaccuratelyboredcylinderstotakethepistons.Thelowerpartoftheblockisknownasthecrankcaseandthishasbearingsthatcarrythecrankshaft.Thewater-jacketsthatsurroundthecylindersarefilledwithcoolant.Thetopofthecylinderblockhasamachinedsurfaceforthecylinderheadandthebottomofthecylinderblockismachinedtoprovideamountingfortheoilpan,orsump.Thecylinderscanbearrangedintheblocksothattheyareinline,asshown,ortheycanbesetatangle(V-typeengine).Thecrankshaftismountedinbearingsinthelowerpartofthecylinderblock(thecrankcase).Theconnectingrodsconnectthepistonstothecrankshaft,whichisrotatedbythepowerstrokesofthepistonswhentheengineisrunning.Theup-and-down,orreciprocating,motionofthepistonsischangedtorotarymotionbythecombinationactionoftheconnectingrodsandthecranksofthecrankshaft.Thetermcrankshaftcomesfromthewordcranked,whichalsomeansbent.Itisashaftwithanumberofcranksorbends.Within-lineengines,thereacrankforeachcylinder,butwithsomeV-typeengines,thereisonlyonecrankforeachpairofcylinders.Theflywheelisaheavycastironwheelattachedtotherearofthecrankshaft.Itreducesenginevibrationsbysmoothingoutthepowerimpulsesofthepistons.Theflywheelabsorbsenergyduringthepowerstrokeandgivesupenergyduringtheotherstrokesandthishelpstokeeptheenginerunningsmoothly.Aringgearfittedtotherimoftheflywheelsothattheenginecanberotatedbythestarterpinionwhenstartingtheengine.Withautomatictransmissions,adriveplateandtorqueconvertertaketheplaceoftheflywheelandperformthesamefunctionsasaflywheel,asfarastherunningoftheengineisconcerned.Thepistonhasgroovesthatcarrythepistonringsandtheseprovideasealbetweenthepistonandthecylinderwall.Compressionringsareusedasagassealandtheoilringisusedtopreventexcessoilfromfindingitswayuppastthepistonintothecombustionchamber.Theconnectingrodhasaremovablecapandasplitbearingatitslowerendwhereitisconnectedtothecrankshaft.Itsupperhasapistonpinthatprovidesawrist-typeofactionwiththepiston.Becauseofitsaction,thepistonpinissometimesreferredtoasawristpin.Thecylinderheadismadeofcastaluminumalloy.Itisboltedtothetopofthecylinderblocksothatitenclosesthecylinders.Ithascombustionchambersabovethecylindersinwhichtheair-fuelmixtureisburnt.Cylinderheadscanbemadeofcastiron,whichismoreresistanttocorrosion,butaluminumalloyisusedforpetrolenginesbecauseithasadvantagesofbetterheattransferandlighterweight.Thecylinderheadhasintakeportsandexhaustports.Theintakevalvesopentheintakeportstoadmitthefuelchargeintothecylinderduringtheintakestroke.Theexhaustvalvesopentheexhaustportstoallowtheburntgasestoleavethecylinderfollowingtheexhauststroke.Thecamshaftandthevalvemechanismareusedtoopenandclosethevalvesatthecorrecttime.Thecamshaftisdrivenfromthecrankshaftathalfthecrankshaftspeed.Thevalvecover,alsocalledthecylinder-headcover,isfittedtothetopofthecylinderhead.Thisenclosesthevalvemechanism.Anadditionalcoverontopoftheenginecoverstheignitioncoils.Thiscylinder-headarrangement,forafour-cylinderengine,hastwocamshaftsandsixteenvalves.Otherfour-cylinderenginescanhavetwocamshaftsandtwelvevalves,oronecamshaftandeightvalves.Thetimingbeltandpulleysdrivethecamshaftathalfthecrankshaftspeed(enginespeed).Atootheddrivebeltisoftenused,butgearsandchainsarealsoused-insomeinstancesabeltandchainarebothused.Onsomeengines,thetimingchainisusedtodrivetheoilpump.Ondieselengines,atimingchainoratiminggearisusedtodrivetheinjectionpumpaswellasthecamshaft.Theoilpan,orsump,holdstheoilfortheenginelubricatingsystem.Theoilpanismadeofsteelthathasbeenpressedtoshape.Otheroilpansaremadeofaluminumalloythathasbeencasttoshape.Theoilpanisboltedtotheundersideoftheenginesothatitclosesoffthecrankcase.Onlytheendsofthecrankshaftthatextendbeyondthecylinderblockareexposed.Variousformsofgasketsandsealsareusedbetweenthesurfaceswherethepartsareboltedtogether.Someoftheseareusedtosealagainstoil,someagainstcoolantandsomeagainstheatandpressure.Someprovideasealonflatsurfaces,othersealagainstrotatingshafts.Aswellasthelargerpartsofanengine,therearenumeroussmallparts.Theseincludebolts,washers,retainers,springandbracketswhichgotomakeupthemechanicalcomponentsoftheengine..EngineSystemsTheenginesystemsthatenabletheenginetostartandtocontinuetooperateareasfollows:Startingsystem;Fuelsystem;Ignitionsystem;Coolingsystem;Lubricatingsystem;Intakesystem;Exhaustsystem;Chargingsystem;Engine’selectroniccontrolsystem.Thesearethesystemsforpetrolengines.Dieselengineshavesimilarsystemsexceptforthefuelandignitionsystems.Somepartsofthesystemsarebuiltintotheengine,somepartsareattachedtotheengineandotherpartsarelocatedonthebodypanelsintheenginecompartment.StartingsystemThestarterisusedtorotatetheengineduringstarting.Itconsistsofanelectricmotorandadrive.Thedrivehasasmallpinionthatmesheswiththeringgearontheflywheelduringstarting.Thebatterysuppliestheelectricalenergytooperatethestarterandrotatetheengineuntilitfiresandrunsonitsown.FuelsystemThesearefourbasictypesoffuelsystems:carburetorsystemsforpetrolengines,fuelinjectionsystemsforpetrolengines,gasfuelsystems(LPGorNGV),anddieselinjectionsystems.Allthesesystemsoperateindifferentways,buttheyallhavesomewheretostorefuel(afueltankoracylinder)andawayofsupplyingtheenginewiththefuel.Theyalsohaveawayofsupplyingairandfuelmixedinthecorrectproportionsothatitcanbeeffectivelyburninthecombustionchambers.IgnitionsystemPetrolenginesandenginesoperatingongasrequireanignitionsystem.Thisisneededtoprovidethesparksthatfirethechargesinthecombustionchambers.Forthisreason,petrolenginesaresometimesreferredtoasspark-ignitionengines.Thisdistinguishesthemfromthemdieselenginesthatdonotneedasparkbecausetheyusecompressionignition.Combustioninadieseloccurswhenthefuelissprayedintothecombustionchamber.Theairinthecylinderisathightemperaturefrombeingcompressed-highenoughtoignitethefuelthatissprayedfromtheinjector.CoolingsystemAconsiderableamountofheatisproducedinanenginebytheburningair-fuelmixture.Someoftheheatisusedtodousefulwork,someistransferredtootherpartsoftheengineandsomeiscarriedawaywithexhaustgases.However,thereisstillenoughheattocausedamageunlessitisremoved.Thisisstillthefunctionofthecoolingsystem,whichremovesaboutone-thirdoftheheatthatisproduced.Thecoolingsystemdoesnotjustremoveheat;itmaintainstheengineatadesirableoperatingtemperature.Inaliquid-cooledengine,thisisdonebycirculatingcoolantthroughthewater-jackets.Inanair-cooledengine,coolingisbyairovercoolingfins.LubricatingsystemTheengine-lubricatingsystemconsistsofanoilpump,areliefvalveandafilter;alsopipes,passagesanddrillingsinvariouspartsofenginethroughwhichtheoilcanflow.Aquantityofoilisheldintheoilpan.Fromthis,oilistakenbytheoilpumpandcirculatedthroughouttheenginebeforereturningtotheoilpan.Theoillubricatesallthemovingpartsandthisisnotonlyreducesfriction,butitpreventswearanddamage.Theoilpumpisdrivendirectlybythecrankshaft.Thissystemhasanoilcooler,locatedatthefiltermountingunderthefilter.IntakesystemInpetrolenginewithelectronicfuelinjection,theintakesystemincludestheaircleaner,thethrottlevalveassemblyandtheintakemanifold.Theintakesystemprovidescleanairandcarriesitintotheenginethroughtheintakemanifold.Nozzlesofthefuelinjectorssprayfuelintotheairpassingfromtheintakemanifoldintotheintakeports.Withcarburetorfuelsystems,amixtureofairandfueliscarriedfromthecarburetor,throughtheintakemanifoldandintotheenginethroughtheintakeports.Forenginesthatoperateongas,amixtureofairandgasiscarriedintotheenginebytheintakemanifold.Inpetrolengineswithfuelinjection,andindieselengines,cleanaironlyisprovidedbytheintakesystem.ExhaustsystemTheexhaustsystemcarriestheburntgasesawayfromtheengineandalsoreducesnoise.Thesystemconsistsoftheexhaustmanifold,exhaustpipes,acatalyticconverterandamuffler.Arrangementsvarywithdifferentengines,theremaybemorethanonemufflerandmorethanonecatalyticconverter.EnginesthatrunonLeadReplacementPetrol(LRP)donothaveacatalyticconverter,neitherdodieselengines.ChargingsystemThealternator,whichisdrivenbytheengine,convertsmechanicalenergytoelectricalenergy.Thebatterysuppliesenergyforthestarter,theignitionsystemandelectricfuelpumpduringthestartingperiod(petrolengine),butoncetheengineisrunning,thealternatorsuppliesalltheelectricalenergy.Italsorechargesthebatterytoreplacetheenergyusedduringstarting.Engine’selectroniccontrolsystemTheengine’selectroniccontrolsystemconsistsofsensors,acontrolunitandactuators.Thecontrolunitreceivessignalsfromthesensorsandthensendssignalstovariousactuators.Therearesensorsontheengine,intheintakesystemandintheexhaustsystem.Theinjectorsareactuatorsthatadjustthesprayoffuel.Therearealsoactuatorsintheignitionsystemthatadvanceandretardthespark.Thesearejusttwoexamplesofwhereelectroniccontrolisused..EngineOperationDuringthedownwardmotionofthepiston,theair-fuelmixtureissuckedfromthecarburetorintothecylinder.Duringtheupwardmotionthemixtureiscompressedbythepistoninthecylinderandignitedbyanelectricspark.Whenthemixtureisburnedinthecylinder,theresultingheatcausesthegasestoexpandwhichexertpressureonthecylinderwallsandonthepiston.Thepiston,beingmovable,ispusheddownwardbythispressuretothefulllengthofitsstroke.Thepressureexertedonthepistonistransmittedthroughtheconnectingrodtothecrankshaftthatismadetorevolve.Thecrankshaftturnsthroughone-halfofarevolutionasthepistonmovesdownward.Aflywheelattachedtothecrankshaftstoresupenergy.Themomentumoftheflywheelcarriesthepistonthroughthebalanceofitsmotionuntilitreceivesanotherpowerimpulse.Theprocessisrepeatedoverandoveragain,thecrankshaftisturningcontinuouslyandtheengineisrunning.Theeventsthatarerepeatedmakeupthecycleoftheengine.Thenumberofstokesofthepistonrequiredtocompletethecyclevarieswiththetypeofengine.Inmodernvehicles,thecycleisextendedthroughfourstrokeofthepistonortworevolutionsofthecrankshaft.Thisiscalledafour-strokecycleengine.Intwostrokecycleengines,thecycleiscompletedintwostrokesofthepistonoronerevolutionofthecrankshaft.Inthefour-strokecycleengine,thefourstrokesarenamedsuction,compression,power,andexhaustinaccordancewiththeoperationofthecyclewhichoccurduringeachparticularstroke.Suctionstroke:duringsuctionstroke,thepistonismoveddownwardbythecrankshaft,whichisrevolvedeitherbythemomentumoftheflywheelorbythepowergeneratedbytheelectricstartingmotor.Theinletvalveremainsopenandtheexhaustvalveisclosedduringthisstroke.Thedownwardmovementofthepistonsucksair-fuelmixtureinthecylinderfromthecarburetorthroughtheopeninletvalve.Herethefuelispetrolmixedwithair,brokenupintoamist,andpartiallyvaporizedinthecarburetor.Compressionstroke:duringcompressionstroke,thepistonmovesupward,thuscompressingthecharge.Ignitionandmuchofthecompressionalsotakeplaceduringthisstroke.Theheatproducedbythecompressionmakesmorehomogeneousmixtureofairandpetrolinsidethecylinder.Theheatmakesthepetroleasiertoburn,whilethecompressionforcesitintoclosercombinationwiththeair.Themixture,undercompression,isignitedbythesparkproducedbyasparkplug,andthecombustionisoverhalf-completedwhenthepistonisatTopDead-Centre(TDC).Boththeinletandexhaustvalvesremainclosedduringthecompressionstroke.Working,powerorexpansionstroke:theexpansionofthegasesduetotheheatofcombustionexertsapressureonthecylinderandpiston.Underthisimpulsethepistonmovesdownwardthusdoingusefulwork.Boththevalvesremainclosedduringthisstroke.Exhauststroke:duringthisstroke,theinletvalveremainsclosedandtheexhaustvalveopens.Thegreaterpartoftheburntgasesescapesbecauseoftheirownexpansion.Thepistonmovesupwardandpushestheremaininggasesoutoftheopenexhaustvalve.Onlyasmallquantityofexhaustgasesremainsintheclearancespacewhichwilldilutethefreshincomingcharge.Thus,inthistypeofengine,fourstrokesofthepistonarerequiredtocompletethecycle,andthefourstrokesmaketworevolutionsofthecrankshaft.Theoperationsarerepeatedoverandoveragaininrunningtheengine.發(fā)動(dòng)機(jī)的組成發(fā)動(dòng)機(jī)是汽車(chē)的重要組成部分，它為汽車(chē)提供行駛的動(dòng)力，對(duì)汽車(chē)而言它就像心臟對(duì)人一樣重要?，F(xiàn)今所有的汽車(chē)發(fā)動(dòng)機(jī)都是內(nèi)燃機(jī)（ICEs），這種發(fā)動(dòng)機(jī)的燃料在氣缸內(nèi)燃燒，燃燒產(chǎn)生的能量直接提供給發(fā)動(dòng)機(jī)。內(nèi)燃機(jī)是將燃料在發(fā)動(dòng)機(jī)氣缸里面燃燒的熱機(jī)。在內(nèi)燃機(jī)運(yùn)轉(zhuǎn)過(guò)程中，儲(chǔ)存在燃料中的化學(xué)能通過(guò)燃燒轉(zhuǎn)變?yōu)闊崮?。?nèi)燃機(jī)的活塞通過(guò)連桿連接在可以旋轉(zhuǎn)的曲軸上，熱能使氣體膨脹推動(dòng)活塞轉(zhuǎn)變?yōu)闄C(jī)械能。燃燒汽油的發(fā)動(dòng)機(jī)叫汽油機(jī)。其它形式的內(nèi)燃機(jī)燃燒重油，其中以柴油機(jī)的應(yīng)用最為廣泛。柴油機(jī)與汽油機(jī)具有相似的構(gòu)造，其區(qū)別在于柴油機(jī)比較笨重。這兩種發(fā)動(dòng)機(jī)都是內(nèi)燃機(jī)，但是兩者具有不同的燃燒系統(tǒng)，并且使用不同的燃料。對(duì)于柴油機(jī)，在進(jìn)氣行程中只有空氣進(jìn)入氣缸。而對(duì)于汽油機(jī)，在進(jìn)氣行程中是吸入空氣和燃料的混合物。通常，柴油機(jī)和汽油機(jī)具有以下區(qū)別：在柴油機(jī)中，燃料是在壓縮行程末期以很好的霧狀形態(tài)噴入氣缸。而在汽油機(jī)中，燃料在進(jìn)氣行程初期被吸入到排氣孔附近。在柴油機(jī)中，燃料是被高壓空氣的高溫點(diǎn)燃的。而在汽油機(jī)中，燃料需要火花才能點(diǎn)燃。柴油機(jī)正常運(yùn)轉(zhuǎn)時(shí)的轉(zhuǎn)速通常比汽油機(jī)的低。柴油機(jī)一般使用比汽油揮發(fā)性小的蒸餾物作為燃料。柴油機(jī)的構(gòu)造使其噪聲比汽油機(jī)大，并且會(huì)產(chǎn)生特有的爆震。小型柴油機(jī)和汽油機(jī)一樣，都被應(yīng)用于乘用車(chē)和輕型商用車(chē)上。大型柴油機(jī)被應(yīng)用于所有的重型商用車(chē)、工程用車(chē)以及農(nóng)用機(jī)械。1.發(fā)動(dòng)機(jī)的類(lèi)型發(fā)動(dòng)機(jī)的類(lèi)型是指發(fā)動(dòng)機(jī)氣缸的排列形式。氣缸可以排列在一條直線上，可以對(duì)置排列，還可以呈一定角度排列（V型）。以這三種排列形式為基礎(chǔ)，又發(fā)展了多種排列形式。直列式發(fā)動(dòng)機(jī)顧名思義，直列式發(fā)動(dòng)機(jī)中各氣缸排成一直列，一個(gè)緊鄰一個(gè)，在一條直線上。大多數(shù)直列式發(fā)動(dòng)機(jī)其氣缸都是垂直的，但也有一些是傾斜的。氣缸傾斜設(shè)置可以降低發(fā)動(dòng)機(jī)的整體高度，這類(lèi)發(fā)動(dòng)機(jī)有時(shí)叫做傾斜發(fā)動(dòng)機(jī)。有些直列式發(fā)動(dòng)機(jī)的氣缸是水平放置的，這類(lèi)發(fā)動(dòng)機(jī)的橫向尺寸會(huì)比較大，不過(guò)這樣可以降低發(fā)動(dòng)機(jī)整高。這類(lèi)發(fā)動(dòng)機(jī)主要用于大型商用車(chē)上，其發(fā)動(dòng)機(jī)架位于駕駛室底部。如圖1-9顯示的是轎車(chē)用直列四缸發(fā)動(dòng)機(jī)的構(gòu)造。圖1-10是側(cè)面剖視圖，可以看到更多零部件，便于分別。水平對(duì)置式發(fā)動(dòng)機(jī)這種排列方式將氣缸布置在曲軸兩側(cè)的平面上，曲軸是剛性較大的短軸，其上有五個(gè)軸承。水平對(duì)置式發(fā)動(dòng)機(jī)有相當(dāng)好的輸出脈沖和平穩(wěn)性?；钊倪\(yùn)動(dòng)方向與對(duì)面的活塞運(yùn)動(dòng)方向相反。由于水平對(duì)置式發(fā)動(dòng)機(jī)的平面布置，大大降低了發(fā)動(dòng)機(jī)的高度，有利于降低＜插圖位置〉汽車(chē)的重心，這樣可以使汽車(chē)更穩(wěn)定。V型發(fā)動(dòng)機(jī)在V型發(fā)動(dòng)機(jī)中，氣缸被布置在兩個(gè)成一定角度的平面上。這樣減小了發(fā)動(dòng)機(jī)的長(zhǎng)度，使其更緊湊。同時(shí)也減小了曲軸的長(zhǎng)度，使之剛性增強(qiáng)。2.發(fā)動(dòng)機(jī)的構(gòu)造及其零部件發(fā)動(dòng)機(jī)總成由許多構(gòu)成它本身的零部件和相關(guān)系統(tǒng)組成。這些系統(tǒng)是發(fā)動(dòng)機(jī)起動(dòng)和維持運(yùn)轉(zhuǎn)所必需的。組成發(fā)動(dòng)機(jī)的各個(gè)零部件可以分成一系列分總成或者相關(guān)的組件，通常也叫它們總成，例如缸蓋總成、活塞總成。有些零部件在發(fā)動(dòng)機(jī)里面，有些在外面，本文的插圖展示了一些發(fā)動(dòng)機(jī)外面的零部件。發(fā)動(dòng)機(jī)各種各樣的零部件通過(guò)螺栓、螺母和其它的緊固件裝配在一起。有些零部件安裝在發(fā)動(dòng)機(jī)里面，還有些固定在外面。機(jī)體是發(fā)動(dòng)機(jī)中最大的零件。其它零部件都是安裝或連接在機(jī)體上的。顧名思義，機(jī)體是一塊金屬鑄體，通常是鑄鐵，但也可以是鑄鋁合金或者鑄鋼。機(jī)體中精確加工了氣缸，可以使活塞在里面運(yùn)動(dòng)。機(jī)體的下部是曲軸箱，里面有安裝曲軸的軸承。在氣缸周?chē)乃桌锍錆M了冷卻液。機(jī)體頂部是一個(gè)機(jī)械加工面，用來(lái)裝配氣缸蓋，底部裝配油底殼或機(jī)油箱。在機(jī)體中氣缸可以布置成一列直線，也可以成一定角度布置（V型發(fā)動(dòng)機(jī)）。曲軸安裝在機(jī)體下部的軸承上（曲軸箱里面）?；钊颓S之間用連桿連接，發(fā)動(dòng)機(jī)運(yùn)轉(zhuǎn)時(shí)曲軸靠活塞的做功行程旋轉(zhuǎn)?；钊耐鶑?fù)運(yùn)動(dòng)通過(guò)連桿和曲軸上曲柄的共同作用轉(zhuǎn)變?yōu)樾D(zhuǎn)運(yùn)動(dòng)。曲軸這個(gè)詞源于英文單詞“cranked”，它是轉(zhuǎn)動(dòng)曲柄的意思，包含有彎曲的意思，通俗地講，曲軸是一根包含若干曲柄的軸。在直列式發(fā)動(dòng)機(jī)中，每個(gè)氣缸對(duì)應(yīng)一個(gè)曲柄，但是在某些V型發(fā)動(dòng)機(jī)中，一對(duì)氣缸會(huì)共用一個(gè)曲柄。飛輪是一個(gè)笨重的盤(pán)形鑄鐵件，它安裝在曲軸后端。它通可以使活塞輸出的動(dòng)力脈沖更平滑，從而減少發(fā)動(dòng)機(jī)的振動(dòng)。它在做功行程吸收能量，在其它行程釋放能量，這樣可以保持發(fā)動(dòng)機(jī)平穩(wěn)地運(yùn)轉(zhuǎn)。飛輪的邊緣裝有一圈齒圈，在發(fā)動(dòng)機(jī)起動(dòng)時(shí)，起動(dòng)機(jī)上的小齒輪通過(guò)齒圈帶動(dòng)飛輪旋轉(zhuǎn)。對(duì)于自動(dòng)變速器，在發(fā)動(dòng)機(jī)起動(dòng)時(shí)，是用傳動(dòng)盤(pán)和變矩器代替飛輪實(shí)現(xiàn)發(fā)動(dòng)機(jī)的起動(dòng)?；钊蜌飧妆谥g靠活塞環(huán)來(lái)密封，活塞環(huán)裝在活塞上的凹槽中。氣環(huán)用來(lái)密封氣體，油環(huán)用來(lái)阻止多余的機(jī)油從活塞上進(jìn)入燃燒室。連桿上有一個(gè)可以拆掉的連桿蓋，其下端通過(guò)一個(gè)剖分的連桿軸承與曲軸連接。連桿上端通過(guò)與活塞銷(xiāo)組成轉(zhuǎn)動(dòng)副而與活塞相連。因?yàn)榭梢赞D(zhuǎn)動(dòng)，所以有時(shí)候也稱(chēng)活塞銷(xiāo)為肘節(jié)銷(xiāo)。氣缸蓋通常是鋁合金鑄件，通過(guò)螺栓將它固定在缸體頂部并且與氣缸相吻合。在氣缸的上部是燃燒空氣與燃料混合物的燃燒室。氣缸蓋也可以是鑄鐵，這樣具有更強(qiáng)的抗腐蝕性，但是由于鋁合金有較好的熱傳導(dǎo)性和較輕的重量，因而用于汽油機(jī)上。氣缸蓋上有進(jìn)氣孔和排氣孔。在進(jìn)氣行程，進(jìn)氣門(mén)打開(kāi)，燃料從進(jìn)氣孔進(jìn)入氣缸。在排氣行程，排氣門(mén)打開(kāi)，燃燒后的廢氣從排氣孔排出。凸輪軸和配氣機(jī)構(gòu)使氣門(mén)在正確的時(shí)刻打開(kāi)和關(guān)閉。凸輪軸由來(lái)自曲軸的動(dòng)力驅(qū)動(dòng)，其轉(zhuǎn)速是曲軸的一半。氣缸蓋罩裝在氣缸蓋的上面，將配氣機(jī)構(gòu)封在里面，并且為發(fā)動(dòng)機(jī)頂部的點(diǎn)火線圈提供額外的保護(hù)。四氣缸發(fā)動(dòng)機(jī)的氣缸蓋包含兩根凸輪軸和十六個(gè)氣門(mén)。在另一種四氣門(mén)發(fā)動(dòng)機(jī)上，含有兩根凸輪軸和十二個(gè)氣門(mén)。還有一種發(fā)動(dòng)機(jī)只有一根凸輪軸和八個(gè)氣門(mén)。皮帶輪通過(guò)正時(shí)皮帶以一半的曲軸轉(zhuǎn)速(曲軸轉(zhuǎn)速即發(fā)動(dòng)機(jī)轉(zhuǎn)速)驅(qū)動(dòng)凸輪軸。常常將有齒輪的皮帶用在這里，但是齒輪和鏈條也會(huì)用于某些發(fā)動(dòng)機(jī)，甚至同時(shí)使用皮帶和鏈條。在某些發(fā)動(dòng)機(jī)上，會(huì)用正時(shí)鏈條來(lái)驅(qū)動(dòng)油泵。在柴油機(jī)中，噴油泵和凸輪軸都是用正時(shí)鏈條或正時(shí)齒輪來(lái)驅(qū)動(dòng)。油底殼或者機(jī)油箱用來(lái)盛放發(fā)動(dòng)機(jī)潤(rùn)滑系統(tǒng)的機(jī)油。油底殼用薄鋼板壓制成型，有些油底殼用鋁合金精密鑄造成型。油底殼用螺栓固定在發(fā)動(dòng)機(jī)下面以便使曲軸箱密封，我們只能看到延伸全曲軸箱外面的曲軸末端。用螺栓連接的零件貼合表面常常要用到各種各樣的墊圈或密封條。有些地方是為了防止泄漏機(jī)油，有些地方是為了防止泄漏冷卻液，還有些地方是為了絕熱和保持壓力。有些密封條用于平整表面，還有些用于轉(zhuǎn)軸上。發(fā)動(dòng)機(jī)除了這些大部件，還有許許多多小零件。包括螺栓、墊圈、止動(dòng)墊圈、彈簧，還有組成發(fā)動(dòng)機(jī)部件的支架。3.發(fā)動(dòng)機(jī)的組成系統(tǒng)以下是發(fā)動(dòng)機(jī)起動(dòng)和保持運(yùn)轉(zhuǎn)需要的系統(tǒng):起動(dòng)系統(tǒng)；燃油系統(tǒng)；點(diǎn)火系統(tǒng)；冷卻系統(tǒng)；潤(rùn)滑系統(tǒng)；進(jìn)氣系統(tǒng)；排氣系統(tǒng)；供電系統(tǒng)；電控系統(tǒng)。這是汽油機(jī)的組成系統(tǒng)。除了燃油系統(tǒng)和點(diǎn)火系統(tǒng)，柴油機(jī)與汽油機(jī)具有相似的系統(tǒng)。這些系統(tǒng)中，有些部件是和發(fā)動(dòng)機(jī)一體的，有些是附加上去的，還有些是安裝在發(fā)動(dòng)機(jī)艙里的。啟動(dòng)系統(tǒng)在發(fā)動(dòng)機(jī)起動(dòng)時(shí)需要用起動(dòng)機(jī)帶動(dòng)。起動(dòng)機(jī)由電動(dòng)機(jī)和驅(qū)動(dòng)器組成。在起動(dòng)時(shí)，驅(qū)動(dòng)器上的小齒輪與飛輪上的齒圈相嚙合。蓄電池給起動(dòng)機(jī)供電帶動(dòng)發(fā)動(dòng)機(jī)轉(zhuǎn)動(dòng)，當(dāng)發(fā)動(dòng)機(jī)著火并自行運(yùn)轉(zhuǎn)時(shí)就算起動(dòng)成功。燃油系統(tǒng)燃油系統(tǒng)有四種類(lèi)型：汽油機(jī)的化