汽车专业英语课件：New Energy of Automobile -

汽车专业英语

NewEnergyofAutomobile6.1StructuralDrawingandTerminology1.auxiliarybattery(备用电池)2.HVbatteryunit(HV电池单元)3.powercable(电缆)4.powermanagementcontrolECU(动力管理控制电控单元)4.ECM(电子编码器)5.P410hybridtransaxle(P410混合传动轴)6.inverter(转向器)7.cooler(冷却系统)8.2ZR-FXEengine(2ZR-FXE发动机)Fig.6-1Maincomponentsofhybridautomobile6.2AlternativeFuelPossibilitiesforFuture1.NaturalGasChinaisalreadyusingsomefuelsotherthangasolineanddieselinthetransportationsector.Naturalgasuseratesarepresentlylow,butmajordevelopmentofthenaturalgasinfrastructureisunderwaytoallowsubstitutionofnaturalgasforcoal,primarilyfordomesticusesandforpowergeneration,inpollutedurbanareas.Naturalgasisacleanfuel,nitrogenoxides(NOx)aretheprimaryemissionofconcern.Itscarbonemissionsareabout25percentlowerthanthoseforgasoline,butwhetherithasnetGHGbenefitsdependsonhowmuchmethaneisleaked.Methaneisamorepowerfulgreenhousegasthancarbondioxide(CO2)byaboutafactorof20,averagedovera100-yearperiod,soa1-2percentleakageofmethanecanoffsetthelowercarbonadvantageofnaturalgas.High-pressuregasislessdensethangasolineandrequiresapressurizedcylindricalstoragevessel,sofuelstoragevolumeimpingestosomeextentonthespaceinsideavehicle.2.LiquefiedNaturalGas(LNG)Anotheralternative,involvesliquidstorageatabout–160℃(–260℉)andapressurejustalittleaboveatmospheric.LNGhasalowerdensitythangasoline,requiresabouta10percentenergypenaltyforliquefaction,andmustbestoredinasophisticatedinsulatedcontainertominimizeboil-off,soitisprobablynotasattractiveanoptionashigh-pressuregasstorageforpassengervehicles.Itismoreattractiveforfleetusewherevehiclesoperateconsistentlyfromacentrallocation.Naturalgasisnowbeingusedinabout110,000vehiclesintwelvecitiesinChina,andabouttwo-thirdsofthesevehiclesarefittedwithdualfuelcapability.Althoughnaturalgassparkignitionenginesstillemitnitrogenoxides,theyarecleanerthandieselengineswhenusedinurbantaxisandbuses.Itislikelythattheuseofnaturalgasfortransportationwillcontinuetoexpand,butitwillremainaminorpartofthetotalenergyusedinthetransportationsector.Indeed,after2010Chinawilllikelyhavetoimportnaturalgastomeetthegrowthinitsdomesticdemand,sothatlarge-scalesubstitutionofnaturalgasforpetroleuminthetransportationsectordoesnotappeartobeasuitableanswertoChina’sconcernsaboutforeignoildependence.However,naturalgasisacleanfuelthathasadvantagesforuseinpollutedurbanareas.尽管天然气点燃式发动机仍然排放氮氧化物，它们的清洁性在应用于城市出租车和公共汽车时好于柴油发动机。很可能运输业使用天然气的规模将继续扩大，但它仍将是一个用于运输部门总能量的较少部分。事实上，2010年以后，中国将可能不得不进口天然气来满足国内需求的增长，因此，替代石油的天然气大规模应用在交通行业似乎并不适合中国过度依赖外国石油的国情。然而，天然气是一种清洁燃料，被用于污染的城市地区极具优势。3.LiquefiedPetroleumGas(LPG)Liquefiedpetroleumgas(LPG),amixtureofpropaneandbutane,isabyproductofoilandgasproductionfromrefineries.Itisausefultransportationfuel,butitsavailabilityislimited.Becausebiofuelsarederivedfromsolarenergy,theyareadispersedenergysourceandconsumeagreatdealofagriculturalland.TheBrazilianautomobilefleetwasfueledbybiofuelsformanyyears,butinlightofcurrentoilprices,dedicatedethanolvehicleshavebeenlargelyabandoned.Biofuelsarelikelytocontinuetobeasmallpartoftheoveralltransportationenergymix,especiallywheretheyareusedasadditivesortofuelasmalllocalvehiclefleet.4.MethanolMethanol,yetanotheralternativevehiclefuelinChina,isbeingusedinShanxiProvinceinsomecommercialvehicles.There,theannualoutputoffuelmethanolfromcoalisexpectedtoreach3.8MMTby2005.China’scoal-bedmethane(CBM)resourcesaresubstantial.Infact,ChinamayhaveuptoathirdoftotalworldwideCBMresources,estimatedtobeintherangeof85-262trillioncubicmeters(m3).SomeCBMisrecoveredcommerciallyintheUnitedStates.China’schemicalprocessingindustryhasalreadyadoptedcoalgasificationtechnology.Becauseconventionalnaturalgasresourcesarescarce,inChina,70percentofitsammonia(NH3)productionin1990wasbasedonthegasificationofsome37MMTofcoal.Thereisalsogreatpotentialtotapthelargereservoirofcoal-bedmethane-byusingthecarbondioxideproducedasabyproductofthemanufactureofammoniafromcoaltostimulatetherecoveryofmethanefromdeep,unmineablecoal-bedformations.Long-termenergycarrierchoices

thatultimatelyareofinterestareeitherelectricityorhydrogen.Electricityisnotacompetitiveenergysourceforpersonalvehicletransportationtodaybecauseofthepoorperformanceandhighcostofbatteriesforonboardvehicleenergystorage.Becauseelectricitycanbeproducedfromcoal,hydropower,ornuclearpower,ithastheinherentpotentialtobealarge-scaleenergysourceinChinaforthetransportationsector.Iffuturetechnologicaldevelopmentsleadtobatteriesthatprovidecost-efficientmobileenergystorage,electricpropulsioncanofferasignificantalternativeforconsideration.长期能源载体的选择，最终是我们感兴趣的电力或者氢。在当今，对于个人车辆运输来说，电力不是一种具有竞争力的能源，因为其综合性能不良和车载储能电池的高成本。由于电力可以从煤炭生产、水电、核电产生，其具有固有的潜力成为中国交通运输部门的一个大规模的能源。如果未来科技发展使电池能提供有成本效益的移动储能器、电动推进器，提供一个可供选择的重要意义的替代物。Butevenifthiscomestopass,theGHGissuesassociatedwiththeproductionofelectricityfromcoalmustbeaddressed.Hydrogen,analternativeenergycarriertoelectricity,hastheadvantageofbeingsomewhateasiertostorethanelectronsinabattery.However,likeelectricity,hydrogenhastobeproducedfromaprimaryenergysource.Thecommercialsourceforhydrogenproductiontodayisnaturalgas.Limitationsontheavailabilityofnaturalgaswillapplyequallytoitsusetoproducehydrogenasatransportationfuel.Ifitwereeconomicallyavailableandiftheinfrastructureexistedtomakeitgeographicallyavailable,itwouldbethebestfuelforfuelcellvehicles.Indeed,thedevelopmentandpromotionoffuelcellvehiclesinChinawilldependonChina’ssourceofhydrogen.OnepossibilityisChina’shugereservoirofcoalandcoal-bedmethane,ifaffordablehydrogenproductioncanbeaccomplishedwiththeminimalemissionofgreenhousegases.CoalisthedominantsourceofChina’senergysupply,butitcontributesonlyabout6percentoftotalenergyuseinthetransportationsector.Theuseofcoalgasificationtoproducesyntheticliquidfuelsorhydrogenfortransportationresultsinenergyinefficienciesandtheincreasedgenerationofgreenhousegases.Althoughlargequantitiesofcarbondioxidearegeneratedinthemanufactureofhydrogen,CO2emissionscouldbereduceddrasticallyifCO2sequestrationtechnologybecomesavailable.Theworld’sscientificcommunityisincreasinglyconfidentthatthesequestrationofasignificantfractionofglobalCO2productionfromtheuseoffossilfuelsoverthenextseveralcenturiesmaybefeasible,especiallyinlightofnewunderstandingofthepotentialforsequestrationingeologicalreservoirs—thatis,depletedoilandgasfields,deepsalineaquifers,anddeepbedsofunmineablecoal.However,thesetechnologiesarestillintheearlystagesofdevelopmentandarelikelytoinvolvesignificantaddedcosts.全球科学界越来越有信心，从使用化石燃料来在较大比例上隔离全球二氧化碳生产，在未来几个世纪可能是可行的，特别是鉴于隔离潜在的地质油藏的新理解——就是，衰竭的石油和天然气领域，深盐碱含水层，不可开采煤矿的深床部分。然而，这些技术仍处于开发的早期阶段，可能会涉及到大量的额外成本。6.3HybridVehicleTechnologies6.3.1HybridPowerTrainsAtypicalcombustionenginedeliverspeakefficiencyonlyataparticularpowerlevel.Today’scarsaredesignedwithoversizedenginesthatareabletoprovidepeakpowerforaccelerationinpassingorclimbinghillsathighwayspeeds.Theengines,therefore,operateinefficientlyatlowurbanspeedswithlowpart-loadefficiencyandburnfuelwhileidlingintraffic.High-powerhybridelectricvehicleNiMHbatteriescurrentlyhaveaspecificpowerofabout400W/kgandaspecificenergyofabout40Wh/kg(ata3-hourrate.)Itisassumedthatbatteryperformancewillimproveoverthenextdecadeorso,especiallyinspecificpower,andthatthegoalsof800W/kgand50Wh/kgarewellwithinreach.Again,lithiumionbatterytechnologymaywellsurpassthisgoal.VehiclestopsandbrakingdecelerationsforatypicalU.S.carforurbandrivingcyclesintheUnitedStates,Japan,andEurope.Avehiclespendsasignificantamountoftimeandfuelduringbothstopsandbrakingdecelerationsandthatthefuelsavingpotentialforengineidle-offisverylarge.Ifenginestart-stopisdesignedtorecoverenergylossesduringvehiclestopsonly,about12-19percentoffuelcouldbesavedforavehicleoperatinginthesecycles.Thefuelsavingswouldbeevenhigherifenginestart-stopweredesignedtorecoverallengineidlinglosses.Thissavingscanbefacilitatedthroughhybridization.Manydifferenttypesofhybridvehicleshavebeendeveloped.Ingeneral,ahybridisdesignedwithanenginethatissmallerthanthatneededforasimilarnonhybridcar.Thehybrid’ssmallercombustionengine(sparkignitionordiesel)operatesclosertoitspeakefficiency,whichoccursnearitsmaximumpoweroutput(alargerenginewouldbeoperatingatlowerefficiencyatthesamepoweroutput).Theenginecanbeshutoffduringvehiclestops,brakingdecelerations,andevenlow-powerdriving,dependingonthespecificdesignofthehybridsystem.Arechargeablebatterysystemisusedtoprovideextrapowerondemand.Atlowspeedsorwhilethevehicleisstopped,unlesstheengineisshutoff,thecombustionengineusesexcesspowertorechargethebatterysystem.Themostefficienthybridvehicleconfigurationalsocapturestheregenerativeenergyfrombrakingthecarandusesittorechargethebattery.Thistypeofhybridoffersmajorimprovementsinefficiencyinurbandrivingcyclesandresultsinlowertotalemissionsbecauseofthesmallerengine-whichisswitchedoffatidleifthebatterysystemisfullycharged.许多不同类型的混合动力汽车已经研发出来。一般来说，针对混合汽车设计的发动机是小于一个类似的非混合动力的汽车。混合动力的小型内燃机(点燃式或柴油)的运行接近其最高效率，其发生在接近最大输出功率(一个更大的发动机将工作在同一功率输出的较低效率下)。在车辆停止时发动机可以关闭，制动减速，甚至低功率驱动，这取决于混合动力系统的特殊设计。一个可充电电池系统用于提供额外的电力需求。在低速或当车辆停止时，除非发动机关闭，否则内燃机使用过量能量给电池系统充电。最高效的混合动力车辆的配置也利用了从制动汽车产生的再生能源并用它来给电池充电。这种类型的混合提供城市驾驶循环的有效改进，主要体现在因为较小型的发动机产生的较低的总排放量，如果电池系统是完全充电的，在怠速时发动机关闭。Thedisadvantagesofhybridsaretheextramaterialsandweightassociatedwithaparallelelectricdrivesystemandwiththebatterysystem.Costsandsomevehicleefficiencypenaltiesareassociatedwiththeaddedcomponentsandthelargerthebatterysystem,thehighertheaddedcostsandthegreatertheweight.Forurbandriving,arelativelysmallbatterysystemmatchesthestop-and-godrivingthatallowsfrequentdraw-downandrechargingofthebattery.Inhighwaydriving,thebatterymaynotrechargeatall,andthereisthedangerthatitmaybedischarged,atwhichpointthecarlosespowerbecauseitisoperatingonanunderpoweredcombustionengine.Forthisreason,theToyotaPriussoldintheUnitedStateshasbothalargerengineandalargerbatterysystemthantheJapanesemodel.Today’shybridelectricvehicles(HEVs)havethreebasicconfigurations:TheseriesHEVconfiguration,inwhichtheenginedrivesageneratorthatproduceselectricity,whichinturnpowersamotortodrivethewheelsand,duringperiodsoflowpowerdemand,chargesthebattery.Brakingenergyalsocanbeusedtochargethebattery.Thisconfigurationiscalledaserieshybridbecausethepowerflowsalongasinglepath.TheparallelHEVconfiguration,inwhichboththeengineandmotordrivethevehiclewheels.Becausethepowerflowsalongtwopaths,thisconfigurationiscalledaparallelsystem.Thissystemalsoallowstheenginetochargethebatteryonboardandrecoverbrakingenergy.Thepower-splitHEVconfiguration,whichisclosertotheparallelconfiguration.Itdiffersinthataplanetarygearsystemcombinedwithastarter-generatorcantransferpowerbetweentheinternalcombustionengineandelectricmotor,bothofwhicharecoupledtothedriveshaft.Inthisconfiguration,theinternalcombustionengineprovidestheprimarypower,withapower-splitdevice(planetarygearwithstarter-generator)sendingpowertoboththedriveshaftandtheelectricmotor.Thissystemissometimescalledanelectricallyvariabletransmissionsystem.AseriesHEVistechnicallythesimplest;however,itusuallyrequireslargeelectricalcomponents,andthusitisheavierandmoreexpensive.Mosthybridcitybusesandheavy-dutyurbantrucksuseseriesconfigurations.Themostpopularchoicefortoday’scommercialandprototypelight-dutyHEVsistheparallelconfiguration.Itrequiresmorecomplicatedsystemintegration,butitislighter,moreefficient,andlesscostlythantheseriessystem(yetmoreexpensivethanthenonhybridtechnologies).Thepower-splitsystemistechnicallymorecomplicated,butpotentiallycanachievethehighestefficiency.6.3.2CategoriesofHybridVehiclesInprinciple,hybridpropulsioncantakemanyforms,fromslightdegreesofhybridization(e.g.,usinganintegratedstarter-generatorwithenginestart-stopcapability)todesignsthatdrivethewheelsonlyelectrically.HEVscanbeclassifiedaccordingtotheportionoftheirmaximumpropulsionpowerprovidedbyanelectricdrive:Minimal(ormini)hybrid-fractionofonboardelectricpowerlessthanabout10percent.Itcanprovideengineidle-offcapability,butnoregenerativebrakingandelectric-onlydriving.Theminimalhybridusuallyusesalow-voltageintegratedstarter-generator,anditsfueleconomybenefitunderU.S.drivingconditionsisabout10percent.Mildandmediumhybrid-fractionofelectricpowerrangesfrom10to25percent;idle-offandsomeregenerativebraking,butnosignificantelectric-onlydriving.ThefueleconomybenefitofsuchHEVsunderU.S.drivingconditionsisabout10-30percent.Fullhybrid-fractionofelectricpowerrangesfrom25to50percent;someelectric-onlydrivingbutnorealtriprange,andbatterynotdesignedforplug-inrecharging.FullHEVsaresometimescalled“power”hybrids.ThefueleconomybenefitofsuchHEVsunderU.S.drivingconditionsisabout30-50percent.EnergyHEVs(alsocalled“chargedepletionhybrids”)haveausefulall-electricdrivingrange(50milesormore)andplug-inrechargingability.Buttheyrequirealargebatterypackandareconsiderablymoreexpensivethantheotherhybrids.Noenergyhybridshavebeenannouncedformassproduction.Anotherreasonmaybethatbatterytechnologiesremaintoolimitedtoprovideadequatecombinationsofefficiencyandperformanceevenwhensupplementedbyanengine-poweredgenerator.Batteriesarecertainlyamajorcostfactorforallhybrids,andsolikepureelectricvehiclesenergyhybridswillcarryaverysubstantialcostpremiumfortheforeseeablefuture.Afullhybridisconsideredamoreradicalchangethantheotherhybridsfromtheconventionalinternalcombustionenginevehicle,whereasaminiormildhybridisconsideredamorenaturalevolutionfromaconventionalvehicle,resultingfromahistoricaltrendofincreasingvehicleonboardelectricpower.Thevehicleelectricpowergrowthratewasabout6percentfrom1920to1940,2percentfrom1940to1970,andagain6percentfrom1970to1990.Industryprojectionsindicatethiselectrificationtrendwillcontinueandprobablygrow.TypicalU.S.carshaveanonboardelectricpowerrequirementofabout1.2kW.Thiselectricpowerrequirementwillincreaseto3-5kWoverthenextfewyearsbecauseoftheadditionoffeaturessuchasheatedseatsandwindows,multimedia,water/oilpumps,powersteering,HVAC(heating,ventilating,air-conditioning)fans,electromagneticvalves,andheatedcatalysts.Currently,mostmajorautomanufacturersandsuppliersareworkingontheso-called“integratedstarter-generator”system,whichwillincreaseonboardelectricpowertoabout10-15kWandsupportfeaturessuchasfastcrank,torquesmoothing,engineidle-off,andlaunchassist,andacertaindegreeofregenerativebraking.TheHondaInsighthybridvehiclefallsintothiscategory.Whenelectricpowerincreasesto20kW,thevehicle’sinternalcombustionenginecanbefurtherdownsized,withsuchaddedfeaturesaselectricHVAC,powerassist,fastheating,andlimphomecapability(ifoutoffuelfortheengine).DaimlerChrysler’sECX2isinthiscategory.Vehicleswithonboardelectricpowercapabilityof10-20kWareoftencalledmildhybridvehicles.AllmajorU.S.andEuropeanmanufacturersarepushingforthisconceptofhybridvehicle,alongwithstandardizationofa42Velectricalsystem.ToyotarecentlyreleasedamildhybridoptionforitsluxuryCrownmodel.Whenonboardelectricpowerincreasesbeyond20kW,asintheToyotaPriusandinproposedfuelcellhybridvehicles,itfinallyreachestheso-calledfullhybridvehicleterritory.Afullhybridvehiclewithasignificantlydownsizedengineandlargeelectricmotor,combinedwithelectricallyvariabletransmissiontechnologieslikethosedevelopedbyToyotaandNissan,willachievethemaximumbenefitfromvehiclehybridization.Butconsumersmayfindfullhybridtechnologytoocostly,placingthetechnologyathighriskofweakcustomeracceptancewithoutgovernmentormanufacturersubsidies.当机载电力增加超过20千瓦，像丰田普锐斯和所提到的燃料电池混合动力汽车，将最终达到所谓的全混合动力车辆的范畴。一个完整的混合动力汽车有明显缩小的发动机和大尺寸的电动机，正如丰田和日产公司的研制中结合了电变量传输技术，来达到车辆混合的最大效益。但消费者可能会发现全混合动力技术太昂贵，没有政府或制造商的补贴，技术的高风险将削弱使用者的接受能力。6.3.3ComparingCommercialandConceptHEVsInrecentyearsvehiclemanufacturershavemadegreatprogressindevelopinganddemonstratingcommerciallyavailableandconcepthybridelectricvehicles.Thesevehiclesincludecommerciallyavailablegasolinehybridcars(ToyotaPriusandHondaInsight)andthedieselhybridconceptcars(FordProdigy,GMPrecept,andDaimlerChryslerESX3)thatemergedfromthePartnershipforaNewGenerationofVehicles.Forexample,onlyPriusandInsighthavefueleconomyratingscertifiedbytheU.S.EnvironmentalProtectionAgency.Otherfueleconomyfiguresarebasedonmanufacturers’claims.6.3.4AssessingtheBenefitsofHybridVehicleFuelEconomyBecausePNGVandotherhybridvehicleshavesuchexpensivedrivetrains,theyhaveemployedunprecedentedlevelsofconventionalvehiclefueleconomytechnologiessuchasaggressiveloadreductionmeasures.Thesemeasuresincludereducingweightandimprovingair/tireresistanceaswellasusinglightweightmaterialsanddieselenginestoreduceweight.ThechoiceofdieselenginesforPNGVvehiclesisaresultofsettinghighefficiencygoalswithinafive-yeartimehorizon.Theassociatedemissionsandcostimpactswereconsideredsecondaryinthiscontext.Itisimportanttounderstandtowhatextentthegainsinfueleconomyareactuallyachievedthroughtheconventionaltechnologies,ontheonehand,andhowmuchareobtainedthrough“pure”hybridtechnologiesandsystems,ontheother.FourcommonelementsthatcontributetogainsinfueleconomyforthesecommercialandconceptHEVsare:对于这些商业和概念的HEVs而言，四种常见元素有助于提高燃油经济：choiceofhigh-efficiencydieselenginesforthethreePNGVhybridvehicles对于三种PNGV混合动力汽车，选择高效柴油发动机。aggressiveloadreductionmeasuresthatlowervehicleairandtiredraglosses,aswellasoverallvehicleweight积极减少负荷的措施是降低车辆的空气和轮胎阻力损失，以及整车的车重。enginedownsizingtoutilizeasmaller,moreadvancedonboardcombustionengine,aswellasimplementationofamoreadvancedtransmissionsystem发动机精简，利用一个更小、更先进的机载燃烧发动机，以及完善更高级的传输系统。systemelectrificationandhybridizationtoutilizeelectricpowertooptimizesystemefficiency,turningofftheengineduringidling,andprovisionofregenerativebraking.系统电气化和混合动力来实现利用电能来优化系统效率，在怠速时关掉发动机和储存再生制动能。Itisnoteasytoestimatethefueleconomybenefitsof“pure”hybridtechnologies.First,hybridbenefitsdependstronglyonthedrivingcycle.Thefueleconomybenefitsofhybridelectricvehiclesaremuchhigherunderstop-and-gotrafficconditionsthanunderfree-flowhighwaydrivingconditions.ThusthefueleconomybenefitsofHEVsinChina’slargecitiesshouldbehigherthanthoseintheUnitedStates.Second,thereisnodoubtthatconventionaltechnologiesincludeallthemeasuresinitems1and2andthathybridtechnologyincludesallthemeasuresinitem4.Itislessclear,however,howitem3shouldbecategorized,becausehybridtechnologiesusuallyrequiresynergiesfromconventionaltechnologiestodeliverthebestbenefits.Itwouldthenseemthatthehybridbenefitsaremorethanitem4alone,butsomewhatlessthanthecombinationofitems3and4.6.3.5IssuesSurroundingFuelCellHybridizationUncertaintiesareassociatedwithwhetherhybridizationwouldbenefitfuelcellvehicles.Intermsofsystemefficiency,unlikeininternalcombustionengineswheretheengineefficiencyincreaseswiththepowerdemand,theefficiencyoffuelcellstackspeaksatalowpowerpointanddecreasesaspowerdemandapproacheseitherthemaximumorminimumlevel.不确定性与混合动力是否有利于燃料电池汽车有关。从系统效率而言，与内燃发动机效率的提高与能源需求有关不同，燃料电池堆的效率在较低功率点出现峰值，能量需求在接近最大或最小水平时减少。Forvehicleswithonboardreformers,theefficiencyofthereformer’stransientoperationcandifferdramaticallyfromthatofitssteady-stateoperation.Asforperformance,thetransientresponsetimeoffuelreformersisacriticalissueandhasaprofoundimplicationforthebenefitsofhybridization(theadditionofbatteriesorotherenergystoragedevices).Intermsofsystemcosts,thetrade-offbetweenthereducedcostassociatedwithdownsizingafuelcellsystemandtheaddedcostofbatteriesandotherhybridcomponentsshouldbeassessed.Thebenefitsandtrade-offsofhybridizingfuelcellvehiclesnotonlydifferfromthosefromhybridizingconventionalinternalcombustionenginevehicles,butalsodifferamongdifferentkindsoffuelcellsystems.6.3.6HybridizationSummaryInspiteofthemanyadvantagesofthehybridvehicle,hybridtechnologiesarestillquiteexpensiveandaddupto20percenttothecostofavehicle.Hybridelectricvehiclesaremanyyearsfromtakingasignificantmarketsharefromtheconventionalinternalcombustionenginevehicles.Inturn,theeconomiesofscaleneededtoreducetheircostdisadvantageprobablywillnotberealizedformanyyears.Inthemeantime,someofthefirststepstowardhybridtechnologies-theintegratedstarter-generator,forexample-willbegintoappearincommercialproducts.IntheUnitedStates,expensivefeaturessuchashybridizationaremorelikelytoappearinhigher-priced(orsubsidized)vehiclesbeforetheymaketheirwayintothewidercommercialmarkets.6.4TheElectricHybridVehicleAhybridvehiclehastwoormorepowersources,andtherearealargenumberofpossiblevariations.Themostcommontypesofhybridvehiclecombineaninternalcombustionenginewithabatteryandanelectricmotorandgenerator.Therearetwobasicarrangementsforhybridvehicles,theserieshybridandtheparallelhybrid.Intheserieshybrid,thevehicleisdrivenbyoneormoreelectricmotorssuppliedeitherfromthebattery,orfromtheICenginedrivengeneratorunit,orfromboth.However,ineithercasethedrivingforcecomesentirelyfromtheelectricmotorormotors.Intheparallelhybrid,thevehiclecaneitherbedrivenbytheICengineworkingdirectlythroughatransmissionsystemtothewheels,orbyoneormoreelectricmotors,orbyboththeelectricmotorandtheICengineatonce.在并联混合动力中，车辆可以由内燃发动机驱动，直接通过一个传输系统到车轮，或通过一个或多个电动机驱动，或由电动机和内燃发动机两者一起驱动。Inbothseriesandparallelhybrids,thebatterycanberechargedbytheengineandgeneratorwhilemoving,andsothebatterydoesnotneedtobeanythinglikeaslargeasinapurebatteryvehicle.Also,bothtypesallowforregenerativebraking,forthedrivemotortoworkasageneratorandsimultaneouslyslowdownthevehicleandchargethebattery.在串联及并联混合动力中，电池可以通过发动机和发电机的移动而充电，所以电池不需要任何一个纯电池车辆那样大。同时，这两种类型允许再生制动，驱动电动机作为发电机，可实现同时减缓车速和给电池充电。Theserieshybrid(asinFig.6-2)tendstobeusedonlyinspecialistapplications.Somespecialall-terrainvehiclesareserieshybrid,withaseparatelycontrolledelectricmotorineachwheel.Themaindisadvantageoftheserieshybridisthatalltheelectricalenergymustpassthroughboththegeneratorandthemotors.Thataddsconsiderablytothecostofsuchsystems.1.electricmotor(电动机)

worksasageneratorwhenusedasregenerativebrake2.rechargeablebattery(可充电电池)3.controller(控制器)4.connectingcables(连接电缆)5.generator(发电机)6.ICengine(内燃机)Fig.6-2SerieshybridvehiclelayoutTheparallelhybrid(asinFig.6-3),ontheotherhand,hasscopeforverywideapplication.Theelectricmachinescanbemuchsmallerandcheaper,astheydonothavetoconvertalltheenergy.Inthesimplest,itcanrunonelectricityfromthebatteries,forexample,inacitywhereexhaustemissionsareundesirable,oritcanbepoweredsolelybytheICengine,forexample,whentravelingoutsidethecity.1.electricmotor(电动机)worksasageneratorwhenusedasregenerativebrake2.ICengine(内燃机)3.transmission(变速器)4.rechargeablebattery(可充电电池)

5.connectingcables(连接电缆)6.controller(控制器)Fig.6-3ParallelhybridvehiclelayoutAlternatively,andmoreusefully,aparallelhybridvehiclecanusetheICengineandbatteriesincombination,continuallyoptimizingtheefficiencyoftheICengine.Apopulararrangementistoobtainthebasicpowertorunthevehicle,normallyaround50%ofpeakpowerrequirements,fromtheICengine,andtotakeadditionalpowerfromtheelectricmotorandbattery,rechargingthebatteryfromtheenginegeneratorwhenthebatteryisnotneeded.Inparallelhybridsystems,itisusefultodefineavariablecalledthe“degreeofhybridization”asfollows:DOH=(electricmotorpower)/(electricmotorpower+ICenginepower).Becausethereisthepossibilityofhybridvehiclesmoving,albeitforashorttime,withtheICengineoffandentirelyunderbatterypower,theycanbecalled“partialzeroemissionvehicles”(PZEVs).Atthetimeofwriting,thehighlyimportantCaliforniaAirResourcesBoard(CARB)identifiesthreelevelsofhybridization,asinTable6-1below.Hybridvehiclesaremoreexpensivethanconventionalvehicles.However,therearesomesavingswhichcanbemade.Inbothseriesandparallelarrangements,theconventionalbatterystarterarrangementcanbeeli