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外文翻译--设计与塑造转矩和速度控制变速器 TSCT.doc

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外文翻译--设计与塑造转矩和速度控制变速器 TSCT.doc

无锡太湖学院DesigningandModelingaTorqueandSpeedControlTransmissionTSCT1BackgroundThePartnershipforaNewGenerationofVehiclesPNGVwasformedbetweentheFederalGovernment,FordMotorCompany,GeneralMotorsCorporation,andChryslerCorporation.ThegoalofthispartnershipwastoallowthemajorU.S.automotivemanufacturestocollaboratewitheachotherandproducehighfuelefficiency,lowemissionsvehiclesforsaletothegeneralpublic.Theperformanceobjectiveforthesemanufacturerswastocreatemidsizedpassengercarscapableofattainingan80mpggasolinecompositefueleconomyratingontheEnvironmentalProtectionAgencyEPAcityandhighwaycycles.HybridvehicletechnologyhasshowngreatpromiseinattainingthegoalssetforthbythePNGV.HybridelectricvehiclesHEVemploytechnologythathelpsbridgethegapbetweenthefuturehopeofanelectricvehicleEVandtodayscurrentvehicles.Withinthepastyearhybridelectricvehicleshavegainedanimportantplaceinthevehiclemarket.AmericanHondaMotorCompany,Inc.iscurrentlyreleasingtheirfirstgenerationHEV,theInsight.TheInsightisacompact,twopassengey,parallelHEVwhichachievesmorethan65mpgcompositeontheEPAtestcyclesthehighestofanyproductionvehicleevertested.ToyotaMotorCorporationhasalsoreleasedahybridvehicleforsaletothegeneralpublic.TheToyotaPriusiscurrentlyforsaleinJapanandwillcometheUnitedStatesinthebeginningoftheyear2000.ThePriusisafourpassengercombinationhybridemployinganagasolineengine,highpowerelectricmotor,andanelectromechanicalcontinuouslyvariabletransmissionCVTcomprisedofaplanetarygeartrainandahighpoweralternator/motor.ItisthroughtechnologyincorporatedinvehiclessuchasthePriusthatautomotivetransmissiondesignandoperationwillmakesignificantnewadvances.1.1CurrentAutomotiveTransmissionTechnologiesWiththeadventoftheautomobilealsocamethecreationoftheautomotivetransmission.Earlyvehiclesweresimplewithmanualcontrolsforallfunctionsincludingthetransmission.Asadvanceshavebeenmadeinvehiclesoverthepastseveraldecades,transmissiontechnologyhasalsoadvanced.Theautomatictransmissionhasnearlyreplacedthemanualtransmissioninallbuteconomyandperformancecars.Thistrendcanbeattributedtoeaseofuse,higherpowerenginesbecomingavailable,andcongestioninurbanareas.Anothernewtransmissiontechnologybeginningtoseeapplicationparticularlyinforeignmarketsisthecontinuouslyvariabletransmissionthatofferscontinuousoperationwithoutshiftingbetweenahighandlowgearratio.Thesethreetypesoftransmissionsareallsimilarinfunctionthoughtheirobjectivesareaccomplishedindifferentways.Thecapabilitiesofthesetransmissionsarelimitedtodecouplingtheenginespeedfromthespeedofwheelsandtherebyprovidingoneofseveralforwardorreversegearratios.Eachtransmissionisalsoasingleinputengineandsingleoutputdrivedevice.Therearetypicallynoprovisionsforattachingmultiplepowersourcesorforextractingpowerfrommorethanonepoint.Theexceptiontothisisheavydutytransmissionsequippedwithprovisionsforapowertakeofffordrivingauxiliarymechanicalequipment.Singleinput,singleoutputoperationlimitsdrivetrainflexibilityfor无锡太湖学院newersystemsemployingmultiplepowersourcessuchasthoseusedinthenextgenerationofhybridvehicles.1.1.1ManualTransmissionOperationManualtransmissionsaretheleastcomplexandoldestdesignofpowertransmissionavailable.Insimplestform,amanualtransmissionisalinearcombinationofaclutchandadirectlygearedconnection.Moresophisticatedexamplesrelyonthisdesignbutaddtheabilitytoselectothergearratiostoallowdifferentoutputspeedsforthesameinputspeed.Ofthesetypesoftransmissions,therearetwovariationssynchronizedandunsynchronized.Synchronizedmanualtransmissionsaretypicallyusedforlightdutyapplications.Coupledtoeachgearisasynchronizerthatallowstheoperatortodisengagetheclutchandselectwhatevergearnecessary.Theselectionofadifferentgearengagesthesynchronizer,whichthenmatchesengineinputspeedandtransmissionoutputspeedbeforethegearsareengaged.Unsynchronizedmanualtransmissionsaremorerobustbynature.Theoperatormustdoubleclutchbetweenshiftstomatchengineandtransmissionspeedmanually.However,thisallowsatransmissionofagivensizetohandlegreaterloadasspacepreviouslyoccupiedbythesynchronizerscannowbededicatedtotheuseofwidergears.Applicationsofthesetypesofmanualtransmissionsareforovertheroadtrucksanduptolargerequipmentwithtotalvehicleweightsover100tons.11.1.2AutomaticTransmissionOperationAutomatictransmissionsareacomplexassemblyofmanycomponentsthatallowforseamlesspowertransmission.Thosecurrentlyavailableinproductionvehiclesusetorqueconverters,clutches,andplanetarygearsetsfortheselectionofdifferentoutputratios.Theengineisconnectedtothetorqueconverterthatactsverymuchlikeaclutchundersomeconditionswhilemorelikeadirectconnectioninothers.Thetorqueconverterisahydrauliccouplingthatwillslipunderlightloadidle,butengageprogressivelyunderhigherload.Whilethetorqueconvertertransmitspowertothetransmissionthereisaspeedreductionacrosstheunitduringlowspeedoperation.Thisreductionistypicallybetween2.51to3.51.Oncehighervehiclespeedsareattained,thetorqueconverterinputandoutputmaybelockedtogethertoachieveadirectdrivethoughtheunit.Theoutputofthetorqueconverteristypicallyconnectedtoahydraulicpumpthatprovidesthenecessarypressuretoengagedifferentclutcheswithinthetransmissionandtheplanetarydrive.Differentgearratiosarecreatedthroughtheuseoftwoormoreplanetarygearsets.Thesegearsetsarecombinedwithclutchesondifferentelements.Byclutchinganddeclutchingdifferentelements,multiplegearratiosarepossible.Basicautomatictransmissionsareequippedwithasinglecontrolinputthatisthrottleposition.Thecombinationofthiswiththehydraulicpressurecreatedwithinthetransmissionallowsformechanicalopenloopcontrolofallgearselections.Newervariationsoftheautomatictransmissionareequippedwithelectronicfeedbackcontrols.Shiftlogicisdependentonmanymorevariablessuchasenginespeed,temperature,currentdrivingtrend,throttleposition,vehicleaccelerations,etc.Thisallowsthetransmissioncontrollertomonitorvehicleoperationandusingarulebasedcontrolstrategydecide,whichgearisbestsuitedtothecurrentdrivingconditions.Newersystemsarealsointegratedwiththeenginecontrollersuchthatavehiclecontrolcomputerhasauthorityoverengineandtransmissionoperationsimultaneously.Thisallowsforsuchfeaturesasincreasingenginespeedduringhighspeeddownshiftstomatchengineandtransmissionspeedforsmoothershiftingandretardingfuelingandignitiontimingduringhighpowerupshiftstoreducejerk.Previously,无锡太湖学院transmissioncontrolwasmuchsimplerbecauseoverrunningclutcheswereemployedinhighergearsthatonlyallowedforcoastingtoconservefuel.11.1.3ContinuouslyVariableTransmissionOperationContinuouslyvariabletransmissionsareoneoftheemergingtransmissiontechnologiesofthelasttwentyyears.Thistypeoftransmissionallowspowertransmissionoveragivenrangeofoperationwithinfinitelyvariablegearratiosbetweenahighandlowextreme.Thesetransmissionsareconstructedusingtwovariablediameterpulleyswithabeltconnectingthetwo.Asonepulleyincreasesinsize,theotherdecreases.Thisisaccomplishedbylocatingononeshaftastationarysheaveandamovablesheave.Forautomotiveapplications,ahydraulicactuatorcontrolsmovementofthesheave.However,centrifugalsystemsalongwithhighpowerelectronicsolenoidsmaybeused.AsecondshaftintheCVTcontainstheotherstationarysheaveandmovablesheavealsocontrolledhydraulically.Aflexiblemetalbeltisfittedaroundthesetwopulleysandthemovablesheavesarelocatedonoppositesidesofthebelt.TherearetwovariationsofthistypeoftransmissionpushbeltandpullbeltPullbeltCVTwerethefirsttypetobemanufacturedduetosimplicity.Aclutchisattachedbetweenthefirstpulleyandtheenginewhiletheoutputofthesecondpulleywasconnectedtoadifferentialandthusthewheels.Ahydraulicpumpisusedtocontrolthediameterofthetwodifferentpulleys.Aspowerisappliedthefirstpulleycreatesatorquethatistransmittedthroughthebeltundertensiontothesecondpulley.Controlofthetransmissionratioisusuallyadirectrelationshipdependentuponthrottleposition.PushbeltCVT,similarindesigntotheVan,aremuchthesameaspullbeltCVT,exceptthatpoweristransmittedthroughthebeltwhileundercompression.Thisprovidesahigheroverallefficiencyduetothebeltbeingpushedoutofthesecondpulleyandloweringfrictionallosses.Currentworkwiththesetransmissionsisbeingfocusedoncreatinglargerunitscapableofhandlingmoretorque.EfficiencyoftheCVTisdirectlyrelatedtohowmuchtensionisinthebeltbetweenthetwopulleys.CVTtorquehandlingcapacityincreasesastensioninthebeltincreases.However,thisincreasedtensionlowerspowertransmissionefficiency.Thebeltmustslideacrossthefacesofeachpulleyasitentersandexitsuponeachhalfrotation.Thisslidingofthebeltcreatesfrictionallosseswithinthesystem.Inaddition,theremaybesignificantparasiticlossesassociatedwithraisingthehydraulicpressurerequiredtomoveormaintainthepositionofthesheavesineachpulley.21.1.4AutomaticallyShiftedManualTransmissionOperationAutomaticallyshiftedmanualtransmissionsareafairlyrecentinnovation.Thebenefitofthemanualtransmissionisthatduetothedirectmechanicalconnectionthroughfixedgearsefficiencyisveryhigh.Thedrawbackisthattheremustbesomeinteractionwiththeuserintheselectionandchangingofgears.Automaticallyshiftedmanualswerecreatedtoaddressthisissue.Thesetypesoftransmissionsaretraditionallysynchronizedmanualtransmissionswiththeadditionofautomationofthegearselectionandcontroloftheclutch.Alogiccontrollerisalsoemployedtodecidewhenandhowtoshift.Automaticshiftingisusuallyaccomplishedthroughtheuseofelectrohydraulics.Ahighpressureelectricpumpsuppliespressuretohydraulicsolenoidsthatareusedtoshiftthetransmission.Ahydraulicramisalsousedtoengageanddisengagetheclutch.Currentversionsofthesetransmissionsalsoemployunsynchronizedgears.Thisallows无锡太湖学院foroverallsmallerpackagingtoaccomplishthesametask.Inputspeedoftheengineismonitoredalongwithlayshaftspeed.Whenagearchangeisinitiated,thecontrolleropenstheclutch,shiftstothedesiredgearwhilematchingengineandlayshaftspeed,andthenclosestheclutchagain.Thisshiftingoperationcanallbeachievedinlessthanonethirdofasecond.Automaticallyshiftedmanualtransmissionsshiftgearsfasterthanhumanlypossible.31.1.5ManuallyShiftedAutomaticTransmissionOperationManuallyshiftedautomatictransmissionsareavariationoncontrolofthetransmission.Theuserisallowedtoselecteitherautomaticormanualshiftingmodes.Duringautomaticmode,thetransmissionfunctionsidenticallytoanautomatictransmission.Whileinmanualshiftmodehowever,thetransmissioncontrollerallowstheuserfullauthorityovergearchangesaslongasthegearchangewillnotoverspeedtheengine.Thismodeofoperationtraditionallyofferstheusertighter,morepositiveshiftfeel.Theonlyrequirementofanautomatictransmissionformanualshiftingisthatshiftsmustbeaccomplishedrapidlyenoughtoallowtheuserafeelingoffluidity.Theactofshiftingmustprovidetheimmediatedesiredresponse.31.1.6PlanetaryGearDriveTransmissionOperationPlanetarygearsetsareuniqueinthatthecombinationofgearscreatesatwodegreeoffreedomsystem.Thegearsetsarecomprisedofaringgear,asungearinthecenter,andplanetarygearsthatcontactboththeringandthesungears.Motionoftheplanetarygearsiscontrolledbythecarrieronwhicheachoftheplanetarygearsrotate.Thecarriermaintainsthepositionoftheplanetsinrelationtoeachotherbutallowsrotationofallplanetsfreely.Inputsoroutputstothegeartrainaretheringgear,sungear,andplanetarycarrier.Byprescribingthemotionofanytwooftheseparameters,thethirdisfixedinrelationtotheothertwo.Byemployingoneplanetarygeartrain,afixedratiobetweeninputandoutputiscreated.Increasingordecreasingthenumberofteethonthesunandringgearscanchangethisratio.Thisinturnchangesthenumberofteethontheplanetarygears,whichhasnoothereffectasthesegearsactasidlers.Whencombiningmorethanoneplanetarygeartrainatonetime,brakingorallowingthemovementofdifferentelementscancreateawiderangeofeffectiveoperationintermsofrelativespeeds,torquetransfer,anddirectionofrotation.Thisisthetypeofsystemthatisusedinautomatictransmissionsdescribedabove.Thesesystemsarealsoemployedinlargestationarypowertransmissionapplications.11.2CurrentHybridElectricVehicleTransmissionDesignHybridvehiclesarevehiclesthatutilizemorethanonepowersource.CurrentpropulsiontechnologiesbeingfavoredarecompressionignitionCIengines,sparkignitionSIengines,hydrogenfueledengines,fuelcells,gasturbines,andhighpowerelectricdrives.Energystoragedevicesincludebatteries,ultracapacitors,andflywheels.Hybridpowertrainscanbeanycombinationsofthesetechnologies.Theaimofthesevehiclesistousecuttingedgetechnologycombinedwithcurrentmassproducedcomponentstoachievemuchhigherfueleconomycombinedwithloweremissionswithoutraisingconsumercostsappreciably.ThesevehiclesaretargetedtobridgethegapbetweencurrenttechnologyandthefuturehopeofaZeroEmissionVehicleZEV,

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