汽车专业英语 2 Internal combustion engine

汽车专业英语

SpecialtyEnglishforAutomobile刘永刚E-mail:andyliuyg@Telhapter2Internalcombustionengine2.1PrincipleofOperationEnergyPowerChemicalenergyBurn//combustionCombustionchamberInternal(external)combustionengineCylinderHeatengineMechanicalpistonInletvalvepistonconnectingrodTDCBDCExhaustvalvecrankEngineTermsTDC（TopDeadCenter）:

thepositionofthecrankandpistonwhenthepistonisfarthestawayfromthecrankshaft.BDC（BottomDeadCenter）:

thepositionofthecrankandpistonwhenthepistonisnearestawayfromthecrankshaft.2.1.2Engineterms

缸径borestrokeTDCBDCClearancevolumeSweptvolumeClearancevolume（余隙/燃烧室容积）:

thevolumeofspaceabovethepistonwhenitisatTDC.Enginecapacity（排量）:

thisisthesweptvolumeofallcylinders.Compressionratio（压缩比）:(sweptvol+clearancevol)/(clearancevol)活塞行程Sweptvolume（有效/工作容积）:thevolumebetweenTDCandBDC.TDCBDCStrokeBoreSweptvolumeEnginecapacityClearancevolumeCompressionratioTwo-stroke:apowerstrokeeveryrevolutionofthecrankFour-stroke:apowerstrokeeveryotherrevolutionofthecrank

每隔一个TopDeadCenterBottomDeadCenterStrokeBoreSweptvolumeEnginecapacityClearancevolumeCompressionratioTwo-stroke//Four-strokerevolution2.1.3Thefour-strokespark-ignitionenginecycle1.Intake/Inductionstroke

进气行程2.Compressionstroke

压缩行程3.Powerstroke

作功行程4.Exhauststroke

排气行程ward(s)后缀表示方向2.1.4EngineoverallmechanicsCrankshaftandConnectingrodssystem

曲柄连杆机构Valvesystem配气机构Fuelsystem供给系Intakesystem进气系统Coolingsystem冷却系Ignitionsystem点火系Startingsystem起动系Lubricationsystem润滑系Exhaustsystem排气系统2.2Engineblockandcylinderhead发动机缸体是发动机的基本骨架，发动机其余的零件或安装在缸体内部，或固定在缸体上。缸体里有气缸、水套和油道，曲轴也固定在缸体底部。除了顶置凸轮轴发动机以外，凸轮轴都固定在缸体内部。大多数汽车上，缸体采用灰铸铁或者灰铸铁和其他金属（例如镍或铬）的合金铸造而成。Theengineblockisthebasicframeoftheengine.Allotherenginepartseitherfitinsideitorfastentoit.Itholdsthecylinders,waterjackets,andoilgalleries.Theengineblockalsoholdsthecrankshaft,whichfastenstothebottomoftheblock.Thecamshaftalsofitsinsidetheblock,exceptonoverhead-camengines(OHC).Inmostcars,thisblockismadeofgrayiron,oranalloy(mixture)ofgrayironandothermetals,suchasnickelorchromium.Engineblocksarecastings.Bemadeof//manufacturedwithWear：穿戴，磨损Linewith:布满；给…加…Thepathtothehouseislinedwithbushes.通向那所房子的小径长满了灌木丛。Thecoatislinedwithsilk.这件外套用绸子作衬里。Cylindersleeves气缸套Cylindersleevesareusedinengineblockstoprovideahardwearingmaterialforpistonsandpistonrings.Theblockcanbemadeofonekindofironthatislightandeasytocastwhilethesleevesusesanotherthatisbetterabletostandup

wearandtear.Therearetwomaintypesofsleeves:dryandwet.发动机缸体中的气缸套为活塞和活塞环提供一种坚硬耐磨的材料。缸体可以采用较轻且易铸造的铁，而气缸套采用更耐磨和耐冲击的材料。气缸套分为两种：干式和湿式。2.2.2Cylindersleeves2.2.3CylinderheadThecylinderheadfastenstothetopoftheblock,justasarooffitsoverahouse.Theundersideformsthecombustionchamberwiththetopofthepiston.In-lineenginesoflightvehicleshavejustonecylinderheadforallcylinders;largerin-lineenginescanhavetwoormore.

气缸盖固定在气缸体的顶部，就像房子的房顶一样。气缸盖底部与活塞头部之间的空间形成了燃烧室。轻型汽车的直列式发动机采用一个气缸盖，较大的直列式发动机采用两个或多个气缸盖。in-line直列式V型Hemi半球形Wedge楔形Basin盆形FlatenginePancakeengine

对置式arrangementCylinderheadIn-lineenginePetrol英gasoline美CombustionchamberGasketSandwichAsbestos石棉Copper铜Oilpanorsump油底壳//集油槽油底壳OilpanCrankcaseOilpumpLubricatingsystemCirculationTheoilpumpinthelubricatingsystemdrawsoilfromtheoilpanandsendsittoallworkingpartsintheengine.

Theoildrainsoffandrunsdownintothepan.Thus,thereisconstantcirculationofoilbetweenthepanandtheworkingpatsoftheengine.

润滑系的机油泵从油底壳抽出机油，并把机油输送给发动机的所有工作部件。机油从油底壳流进流出。因而在油底壳和发动机的工作部件之间就有机油定向循环流动。OilPan/Sump

油底壳OilPanComponentsofatypical,fourstrokecycle,D(dual)OHCpistonengine.(E)Exhaustcamshaft,(I)Intakecamshaft,(S)Sparkplug,(V)Valves,(P)Piston,(R)Connectingrod,(C)Crankshaft,(W)Waterjacketforcoolantflow.cylinderheadheadcoverwaterjacketoilgalleryoilpangasketcylindercylindersleeveengineblockcrankcaseEngineblockandCylinderhead

曲轴箱气缸盖罩气缸气缸套气缸体油底壳气缸盖衬垫水套油道Crankshaft曲轴Pistonring活塞环Piston(crown＼skirt)活塞（头部＼裙部）Pistonpin活塞销Connectingrod连杆Big-end连杆大头Small-end连杆小头Cap连杆盖Shellbearing轴瓦Mainbearingjournal主轴颈Connectingrodjournal

连杆轴径Flywheel飞轮2.3Piston,ConnectingrodandCrankshaftThepistonisanimportantpartofafour-strokecycleengine.Mostpistonsaremadefromcastaluminum.Thepiston,throughtheconnectingrod,transferstothecrankshafttheforcecreatedbytheburningfuelmixture.Thisforceturnsthecrankshaft.Thin,circular,steelbandsfitintogroovesaroundpistontosealthebottomofthecombustionchamber.Thesebandsarecalledpistonrings.Thegroovesintowhichtheyfitarecalledringgrooves.Apistonpinfitsintoaroundholeinthepiston.Thepistonpinjoinsthepistontotheconnectingrod.Thethickpartofthepistonthatholdsthepistonpinisthepinboss.大多数活塞由铝铸造而成。通过连杆的作用，活塞把可燃混合气燃烧产生的力传递给曲轴，带动曲轴旋转。PistonAssemblyFlatConcaveDomeRecessedIndieselengines,thecombustionchambermaybeformedtotallyorinpartinthepistoncrown,dependingonmethodofinjection.

柴油机发动机根据喷油方法不同，活塞头部可以形成全部燃烧室，也可以是燃烧室的一部分．PistonCompressionring:气环压缩环压环Oilring：油环PistonringsGasRingsOilRingsTheconnectingrodismadeofforgedhigh-strengthsteel.Ittransmitsforceandmotionfromthepistontothecrankpinonthecrankshaft.Theconnectingrodlittleendisconnectedtothepistonpin.Abushmadefromasoftmetal,suchasbronze,isusedforthisjoint.Thelowerendoftheconnectingrodfitthecrankshaftjournal.Thisiscalledthebigend.

连杆采用高强度锻造钢。连杆将活塞的力和运动传递给曲轴上的曲柄销。连杆小头与活塞销连接，连接处有像青铜这样软金属制成的衬套，连杆下端连接在曲柄轴径上，称为连杆大头。2.3.3connectingrodThepistonisanimportantpartofafour-strokecycleengine.Mostpistonsaremadefromcastaluminum.Thepiston,throughtheconnectingrod,transferstothecrankshafttheforcecreatedbytheburningfuelmixture.Thisforceturnsthecrankshaft.Thin,circular,steelbandsfitintogroovesaroundpistontosealthebottomofthecombustionchamber.Thesebandsarecalledpistonrings.Thegroovesintowhichtheyfitarecalledringgrooves.Apistonpinfitsintoaroundholeinthepiston.Thepistonpinjoinsthepistontotheconnectingrod.Thethickpartofthepistonthatholdsthepistonpinisthepinboss.2.3.4crankshaftConjunction:连接，同时发生aconjunctionoffavourablepoliticalandeconomiccircumstancesInconjunctionwith：和……一起Reciprocating:往复bearingjournal:轴颈Alloy:n/vt

合金，mix(metals)tomakeanalloythrow：半径，行程TDC、BDC、Viceversa2.3.5cylindernumberingandfiringorderImpluse//pulse脉冲Flow流程Space：把...分隔开,排开,按一定距离安排开

spaceoutthelampposts30metersapartInterval间隔Diagram:简图，示意图Firingorder:点火顺序2.5ValvesystemThevalvesystemismadeupofthosepartsneededtoopenandclosethevalvesatjusttherighttime.Tocoordinatethefour-strokecycle,agroupofpartscalledthevalvetrainsopensandclosedthevalves(movesthemdownandup,respectively).Thesevalvemovementsmusttakeplaceatexactlytherightmoments.Theopeningofeachvalveiscontrolledbyacamshaft.Thecamisanegg-shapedpieceofmetalonashaftthatrotatesincoordinationwiththecrankshaft.Themetalshaft,calledthecamshaft,typicallyhasindividualcamsforeachvalveintheengine.Asthecamshaftrotates,thelobe,orhighspotofthecam,pushesagainstpartsconnectedtothestemofthevalve.Thisactionforcesthevalvetomovedownward.Thisactioncouldopenaninletvalveforanintakestroke,oropenanexhaustvalveforanexhauststroke.凸轮是一个蛋形的金属块，它安装在同曲轴协调运转的一根金属轴上，该轴称为凸轮轴，其上有同发动机每一个气门对应的凸轮。当凸轮轴旋转时，凸轮的最高点，也就是凸圆，推动连接气门杆的部件，使得气门向下运动，在进气冲程打开进气门，在排气冲程打开排气门。Valvesinmoderncarenginesarelocatedinthecylinderheadatthetopoftheengine.Thisisknownasanoverheadvalve(OHV)configuration.Inaddition,whenthecamshaftislocatedoverthecylinderhead,thearrangementisknownasanoverheadcamshaft(OHC)design.Somehighperformanceengineshavetwoseparatecamshafts,oneforeachsetofinletandexhaustvalves.Theseenginesareknownasdualoverhead-camshaft(DOHC)engine.Inthisarrangement,thecamlobespushagainstroundmetalcylinderscalledcamfollower.Asthelobeofthecamcomesupunderthecamfollower,itpushesthecamfollowerupward(awayfromthecamshaft).Thecamfollowerridesagainstapushrod,whichpushesagainstarockerarm.Therockerarmpivotsonashaftthroughitscenter.Asonesideoftherockerarmmovesup,theothersidemovesdown,justlikeaseesaw.Thedownward-movingsideoftherockerarmpushesonthevalvestemtoopenthevalve.Push-rodvalvetrainRocker-arm（摇臂）CamshaftTappet(Camfollower)Push-rodValveclearancesValveSpringValvestemValveseat（气门座）ValveheadPistonRocker-shaft2.5.2ValveclearanceWhentheenginerunsincompressionstrokeandpowerstroke,thevalvesmustclosetightlyontheirseatstoproduceagas-tightsealandthuspreventthegasesescapingfromthecombustionchamber.

Ifthevalvesdonotclosefullytheenginewillnotdevelopfullpower.Alsothevalveheadswillbeliabletobeburntbythepassinghotgases,andthereisthelikelihoodofthepistoncrowntouchinganopenvalve,whichcanseriouslydamagetheengine.当发动机处于压缩行程或做功行程时，气门必须紧闭在气门座上，提供很好的密封性，从而防止气体从燃烧室中溢出。如果气门不能完全关闭，则发动机不能产生最大的功率。另外气门头容易被流经的高温气体烧蚀，有可能导致活塞头部冲击打开的气门，会严重破坏发动机。为保证气门能完全关闭，必须在气门工作机构中留有间隙。这就意味着气门传动机构和气门之间有足够远的距离，从而保证气门能够在弹簧的作用下紧闭气门座。但是如果气门间隙过大，会产生轻微的金属敲打声。Sothatthevalvescanclosefullysomeclearanceisneededintheoperatingmechanism.Thismeansthattheoperatingmechanismmustbeabletomovesufficientlyfarenoughawayfromthevalvetoallowthevalvestobefullyclosedagainstitsseatbythevalvespring.However,iftheclearanceissettoogreatthiswillcausealightmetallictappingnoise.

2.5.3valvetimingThetimeatwhichvalvesopenandclose(valvetiming)anddurationofvalveopeningisstatedindegreesofcrankshaftrotation.Forexample,theintakevalvenormallybeginstoopenjustbeforethepistonhasreachedtopdeadcenter.ThevalveremainsopenasthepistontravelsdowntoBDCandevenpastBDC.Thisisintakevalveduration.Anexampleofthiscouldbestatedasfollows:IOat17oBTDC,ICat51oABDC(or,intakeopens17obeforetopdeadcenter,intakecloses51oafterbottomdeadcenter).Intakevalvedurationinthiscaseis248oofcrankshaftrotation.Itisapparentfromthisdescriptionthattheexhaustvalvestaysopenforashortperiodoftimeduringwhichtheintakevalveisalsoopen.Inotherwords,theendoftheexhauststrokeandthebeginningoftheintakestokeoverlapforashortperiodoftime.Thisiscalledvalveoverlap.Valvetimingandvalveoverlapvaryondifferentengines.从上述描述显而易见，排气门开启时，有一小段时间，进气门也是开启的。换句话说，排气行程终了和进气行程初期有一短时间的重叠，这就称之为气门重叠。不同的发动机具有不同的气门正时和气门重叠。Theentirevalve-trainassemblycanbeviewedasaspring/masssysteminwhichtheconversionfromstoredtofreeenergycausesforcedvibration.Valve-trainassemblieswithoverheadcamshaftscanberepresentedwithsufficientaccuracybya1-masssystem(consistingofthemovingmass,thevalve-trainassemblystiffnessandcorrespondingdamping).

整个气门传动机构可以被看做成一个弹簧/质量系统，其储存的能量转换为自由能量时产生了受迫振动。顶置凸轮轴的气门传动总成可非常精确地用单质量系统（包含移动的质量、气门机构总成的刚度和相应的阻尼）表示。2.5.4camdesignandcontroldynamics2.5.5camshaftdrivemechanismEachcammustrevolveonceduringthefour-strokecycletoopenavalve.Acycle,remember,correspondswithtworevolutionsofthecrankshaft.Therefore,thecamshaftmustrevolveatexactlyhaftthespeedofthecrankshaft.Thisisaccomplishedwitha2:1gearratio.Agearconnectedtothecamshafthastwicethenumberofteethasagearconnectedtothecrankshaft.BeltdriveCog-typebelt齿形带Reinforce：加强Fiberglass：玻璃纤维Slotted：开槽ChaindriveGeardriveVariablevalvetiming

Ininternalcombustionengines,variablevalvetiming,oftenabbreviatedtoVVT,isagenerictermforanautomobilepistonenginetechnology.VVTallowsthelift,durationortiming(invariouscombinations)oftheintakeand/orexhaustvalvestobechangedwhiletheengineisinoperation.Theprofile,orpositionandshapeofthecamlobesontheshaft,isoptimizedforacertainenginerevolutionsperminute(RPM),andthistradeoffnormallylimitslow-endtorque,orhigh-endpower.VVTallowsthecamtimingtochange,whichresultsingreaterefficiencyandpower,overawiderrev-range.通用、专业术语；轮廓、型线；转速/分；低端扭矩；高端功率Athighenginespeeds,anenginerequireslargeamountsofair.However,theintakevalvesmayclosebeforealltheairhasbeengivenachancetoflowin,reducingperformance.Ontheotherhand,ifthecamkeepsthevalvesopenforlongerperiodsoftime,aswitharacingcam,problemsstarttooccuratthelowerenginespeeds.Thiswillcauseunburntfueltoexittheenginesincethevalvesarestillopen.Thisleadstolowerengineperformanceandincreasedemissions.Forthisreason,pureracingenginescannotidleatthelowspeeds(around800rpm)expectedofaroadcar,andidlespeedsof2000rpmarenotunusual.PressuretomeetenvironmentalgoalsandfuelefficiencystandardsisforcingcarmanufacturerstoturntoVVTasasolution.MostsimpleVVTsystemsadvanceorretardthetimingoftheintakeorexhaustvalves.Others(likeHonda'sVTEC)switchbetweentwosetsofcamlobesatacertainengineRPM.FurthermoreHonda'sI-VTECcanalterintakevalvetimingcontinuously.VTEC(VariableValveTimingandLiftelectronicControl)可变气门配气相位和气门升程电子控制系统

isavalvetrainsystemdevelopedbyHondatoimprovethevolumetricefficiencyofafour-strokeinternalcombustionengine.Thissystemusestwocamshaftprofilesandelectronicallyselectsbetweentheprofiles.ItwasinventedbyHondaR&DengineerIkuoKajitani.VTECwasthefirstsystemofitskind,thoughothervariablevalvetimingandliftcontrolsystemshavebeenproducedbyothermanufacturers(MIVECfromMitsubishi,VVTL-ifromToyota,VarioCamPlusfromPorsche,VVLfromNissan,etc)VVT-i,orVariableValveTimingwithintelligence,isanautomobilevariablevalvetimingtechnologydevelopedbyToyota,similarinperformancetotheBMW'sVANOS.生词表EngineStoke：inductionCompressionpoweremissionTop/bottomdeadcenterSweptvolumeCompressionratioClearancevolumeEnginecapacityMechanicsMechanism[`mekənizəm]BlockWaterjacketCylindersleeve(dryorwet)CylinderheadCombustionchamberGasketOilpansumpPiston/-ring/-pinConnectingrodCrankshaftBearingjournalReciprocateFiringorderFlywheelPistoncrown/skirtDiagram生词表mountingAmplitudeRollPitchyawValvesystemCamshaftOverheadHeadCamshaftvalvetrainPush-rodvalvetrainCamfollowerPushrodRockerarmValveseatValveclearanceValvetimingIntake/exhaustvalveBelt/chain/gearTeeth(gear)Today,internalcombustionenginesincars,trucks,motorcycles,aircraft,constructionmachineryandmanyothers,mostcommonlyuseafour-strokecycle.Thefourstrokesrefertointake,compression,combustion(power),andexhauststrokesthatoccurduringtwocrankshaftrotationsperworkingcycleofthegasolineengineanddieselengine.Thecyclebeginsattopdeadcenter(TDC),whenthepistonisfarthestawayfromtheaxisofthecrankshaft.Ontheintakeorinductionstrokeofthepiston,thepistondescendsfromthetopofthecylinder,reducingthepressureinsidethecylinder.Amixtureoffuelandairisforced(byatmosphericorgreaterpressure)intothecylinderthroughtheintake(inlet)port.Theintake(inlet)valve(orvalves)thenclose(s),andthecompressionstrokecompressesthefuel–airmixture.Theair–fuelmixtureisthenignitedneartheendofthecompressionstroke,usuallybyasparkplug(foragasolineorOttocycleengine)orbytheheatandpressureofcompression(foraDieselcycleorcompressionignitionengine).Theresultingpressureofburninggasespushesthepistonthroughthepowerstroke.Intheexhauststroke,thepistonpushestheproductsofcombustionfromthecylinderthroughanexhaustvalveorvalves.汽车的动力源是发动机。发动机乃是将某一种形式的能量转变为机械能的机器。将热能转变为机械能的发动机，称之为热力发动机，其中的热能是由燃料燃烧所产生的。内燃机是热力发动机的一种，其特点是液体或气体燃料和空气混合后直接输入机器内部燃烧而产生热能，然后再转变为机械能。Engineisthepowerunitofautomobiles(motorvehicle),whichisacategoryofmachinethatconvertsoneformofenergytoanother.Engine,whichconvertsheat(thermal)energyobtainedbycombustionoffueltomechanicalenergy,iscalledasheatengine.Internalcombustionengineisonetypeofheatengine,whosefeatureisthatgasorliquidfuel,aftermixingwithair,isimportedintoengineandburnedtoreleaseheatenergy,whichisthenconvertedtomechanicalenergy.2.6GasolinefuelsystemGasolineisdistilledfromcrudepetroleum.Gasolineishighlyflammable,meaningitburnseasilyinthepresenceofair.汽油是从天然石油中提取出来的，汽油具有较高的易燃性，这就意味着汽油容易在空气中燃烧。[di'stil][pi'trəuliəm]['flæməbl]Gasolinemustvaporizeeasily.

Thischaracteristic,called

volatility,isimportant.

However,itmustnotvaporizetooeasily,oritwillturntovaporinsidethefueltankorfuellines.

Insidethe

fuelline,fuelvapormayblocktheflowofliquidgasoline.

Thisiscalledvaporlock.

Vaporlockiscommoninfuellineswheretheinletsideofthepumpisexposedtohightemperatures.汽油必须容易蒸发，这个特性也叫挥发性，是十分重要的。但是汽油不能太容易蒸发，否则汽油会在油箱或油路中蒸发。燃油在油路中的蒸发会堵塞液体汽油的流通，称之为气阻。油泵的入口端暴露在高温下时，油路中常出现气阻。Additive添加物Increasingthepressureofthefuelmixtureinthecombustionchamberbeforeignitionhelpstoincreasethepowerofanengine.Thisisdonebycompressingthefuelmixturetoasmallervolume.Highercompressionratiosnotonlyboostpowerbutalsogivemoreefficientpower.Butasthecompressionratiogoesup,knockingtendencyincreases.Theoctanenumberofagasolineisameasureofitsantiknockqualityorabilitytoresistdetonationduringcombustion.Detonation,sometimesreferredtoasknock,canbedefinedasanuncontrolledexplosionofthelastportionoftheburningfuel-airmixtureduetoexcessivetemperatureandpressureconditionsinthecombustionchamber.Sincedetonationcreatesshockpressurewaves,andhenceaudibleknock,ratherthansmoothcombustionandexpansionofthefuelairmixture,itresultsinlossofpower,excessivelocalizedtemperatures,andenginedamageifsufficientlysevere.Therearetwocommonlyusedmethodsofdeterminingtheoctanenumberofmotorgasoline—themotormethodandtheresearchmethod.Bothusethesametypeoflaboratorysingle-cylinderengine,whichisequippedwithavariableheadandaknockmetertoindicateknockintensity.Usingthetestsampleasfuel,theenginecompressionratioandtheair-fuelmixtureareadjustedtodevelopaspecifiedknockintensity.Twoprimarystandardreferencefuels,normalheptaneandiso-octane,arbitrarilyassigned0and100octanenumbers,respectively,arethenblendedtoproducethesameknockintensityasthetestsample.Thus,ifthematchingreferenceblendismadeupof15%n-heptaneand85%iso-octane,thetestsampleisrated85motororresearchoctanenumber,accordingtothetestmethodused.马达法研究法2.6.2Excess-airfactorAir-fuelratio(AFR)isthemassratioofairtofuelpresentduringcombustion.MostpracticalAFRdevicesactuallymeasuretheamountofresidualoxygen(forleanmixtures)orunburnthydrocarbons(forrichmixtures)intheexhaustgas.Lambda(λ)isthemeasureofhowfarfromstoichiometry（理想配比）thatmixtureis.Lambdaof1.0isatstoichiometry,richmixturesarelessthan1.0,andleanmixturesaregreaterthan1.0.Excess[ik‘ses,’ekses]名词

//形容词过度过分过分的Excessive[ik'sesiv]Fuelconsumption燃油消耗Fueleconomy燃油经济性Pollutantemission废气排放Emission排放Accelerationperformance加速性能2.6.3AdaptationtooperatingconditionsColdstart冷起动Post-startphase起动后Warm-up暖机Acceleration加速Partload部分负载Fullload满载Idling怠速Overrun超速Engine-speedlimiting发动机限速

fueltank油箱fuelfilter汽油滤清器fuelpump汽油泵Carburetor(mix)化油器airfilter空气滤清器burnBasicpartsofacarburetorfuelsystem2.6.4CarburetorfuelsystemFuelpump:

Mostcarstodayhaveamechanicalfuelpump.Thispumpsfueloutofthetankandthroughthefuellinestothecarburetororinjectionsystem.Inmostcars,thepumpismountedontheengineblock.Somecarshaveanelectricfuelpump.Thispumpmountsinthefueltankwiththefuelpickupandthefuel-gauge-sendingunit.

当前大多数汽车采用机械汽油泵，汽油泵从油箱抽出汽油，通过油管送到化油器或喷射系统。大部分汽车的汽油泵安装在缸体上。一些汽车采用电动汽油泵，汽油泵安装在油箱上，附带有油量传感器和燃油表油量传送装置。DiaphragmspringRockerarmInletportOutletportDiaphragmCam(lobe)Acarburetordeliversfuelinproportiontotheamountofairflowingthroughit.Asyoupressontheacceleratorpedal,thethrottlevalveopenswidertodrawmoreairthroughthecarburetor.Thecarburetorprovidesricherorleanermixtures,dependingonanumberoffactors:enginespeed,load,temperature,andthrottleposition.Tomeetcomplicateddemands,acarburetorisahighlyintricatedevice,withmanyinternalpassagesandparts.化油器传输的燃料和流经化油器的空气流量成一定比例。踏下加速踏板，节气门开度变大，化油器吸入的空气量增加。化油器可提供过浓或过稀的