外文翻译--目前的传动系概念.doc

翻译CURRENTDRIVELINECONCEPTS1ENGINEDEVELOPMENTSGASOLINEANDDIESELENGINESARETHEDOMINANTDRIVEUNITSOFTODAYHYBRIDCONCEPTSANDFUELCELLSHAVESOFARONLYCONQUEREDMARKETNICHESORHAVENOTYETDEVELOPEDBEYONDTHEDESIGNSTAGENEWINJECTIONTECHNOLOGIES,SUCHASPUMPNOZZLEANDCOMMONRAIL,ARENOWCOMMONFORDIESELENGINESTHISRESULTEDINSIGNIFICANTFUELSAVINGSANDIMPROVEDDRIVINGDYNAMICSDUETORAISEDTORQUEANDPERFORMANCEPRESENTLY,MULTIPOINTINJECTIONISTHEDOMINANTMETHODFORGASENGINECONCEPTSINCREASINGLYSTRINGENTEMISSIONLAWS,THEREQUIREMENTSOFTHEEUROPEANPARLIAMENTANDTHEVOLUNTARYCOMMITMENTOFTHEEUROPEANAUTOMOBILEINDUSTRYTOREDUCETHEAVERAGECO2EMISSIONOFNEWLYREGISTEREDPASSENGERCARSBY25BYTHEYEAR2008COMPAREDTOTHEYEAR1995,WILLREQUIRESIGNIFICANTREDUCTIONSINFLEETCONSUMPTIONANDEMISSIONSWITHINTHENEXTFEWYEARSTHISWILLRESULTINADIVERSIFICATIONOFDRIVECONCEPTSFORGASENGINESDIVERSIONSWILLSHARETHEMARKETWITHDISPLACEMENTREDUCED,SUPERCHARGEDENGINES,ELECTROMECHANICALANDMECHANICALVALVEGEARSYSTEMSANDTHEIRCOMBINATIONSTHEFUTUREORIENTEDCONCEPTSOFCOMPLETEDETHROTTLINGOFTHEGASENGINEBYMEANSOFCHARGESTRATIFICATIONORVOLUMETRICEFFICIENCYCONTROLANDSHIFTINGOFTHELOADCYCLEINTOTHEEFFICIENCYOPTIMALRANGEOFTHEENGINEGRAPHWILLDECISIVELYCONTRIBUTETOTHETECHNOLOGYOFTHEGASENGINEINTHECOMINGDECADESDOWNSIZINGANDSUPERCHARGINGWILLSIGNIFICANTLYRAISESPECIFICMAXIMUMENGINETORQUELEVELSINTHENEXTFEWYEARS2TRANSMISSIONTYPESTHEMANUALTRANSMISSION/MTANDTHEAUTOMATICTRANSMISSION/ATARETHETRANSMISSIONSPRESENTLYFIRMLYESTABLISHEDINTHEMARKETFORSOMEYEARSTHEMARKETHASSEENTHEAPPEARANCEOFTHEAUTOMATEDMANUALTRANSMISSION/AMTANDTHECONTINUOUSLYVARIABLETRANSMISSION/CVT,WHOSESHARESINTHEMARKETARESTILLVERYSMALLMANUALTRANSMISSIONSARECHEAP,OFRELATIVELYSMALLSIZE,ANDTHEIRSPURGEARSPROVIDEGOODEFFICIENCY,CONSUMPTIONLARGELYDEPENDSONTHEDRIVER’SSHIFTINGSTYLEANDTHEVEHICLECONCEPTTHECOMFORTOFANAUTOMATICTRANSMISSIONISAPPROACHEDTHROUGHAUTOMATEDSHIFTINGANDCLUTHINGMOREGEARSSNDTHECONCOMITANTENHANCEDSPACINGALSOINCREASECOMFORTHIGHEFFICIENCY,FAVORABLEWEIGHTANDLOWCOSTAREFACTORSTHATATERETAINEDTRACTIONINTERRUPTION,ASSOCIATEDWITHAUTOMATEDSHIFTINGANDREGARDEDASIMPAIRINGCOMFORT,WILLBEREDUCEDINFUTUREAMTSBYANOPTIMIZEDGEARSHIFTPROCESSTHEPOWERSHIFTINGDOUBLECLUTCHTRANSMISSIONWITHTWOSEPARATETRANSMISSIONINPUTSHAFTSISPARTOFTHISDEVELOPMENTGEARSAREPRESELECTEDINTHELOADFREESECTIONOFTHETRANSMISSION,GEARSTEPSATECHANGEDUNDERFULLLOADTHROUGHCONTROLLEDTROLLEDTORQUETRANSFERFROMTHEFIRSTTOTHESECONDCLUTCHATSHAVEUNDERGONEACONTINUOUSDEVELOPMENTPROCESSINRECENTYEARSANHAVEBECOMEEVENMORECOMFORTABLE,LIGHTERANDECONOMICALNEWGEARSETCOMFORTABLE,LIGHTERANDECONOMICALNEWGEARSETCONCEPTSANDMOREGEARSTEPSWILLCONTINUETHISTRENDTHEIRVERYHIGHLEVELOFCOMFORT,HOWEVER,ISASSOCIATEDWITHACOMPLEXDESIGNANDARELATIVELYHIGHWEIGHTANDLIMITEDEFFICIENCYCOMFORTABLESHIFTINGWITHTHECVTISPRINCIPLERELATEDACCELERATIONIDEALLYFOLLOWSTHETRACTIONHYPERBOLA,THEINITIALENGINESPEEDINCREASEFLLOWEDBYCOMTINUOSTRANSMISSIONRATIOVARIATION,HOWEVER,ISNEWTHEREISADELAYBETWEENTHEINITIATIONOFACCELERATIONANDTHEFOLLOWINGRESPONSETHEHYDRAULICALLYPRODUCEDFRICTIONALCONNECTIONINTHEVARIATOR,WHICHTRANSFERSTHETORQUETOTHEOUTPUT,SUGGESTSINCREASEDCONSUMPTIONWIDESPACING,HOWEVER,LOWERSTHISFORVEHICLESWITHMANUALTRANSMISSIONS3STARTINGCOMPONENTSTODAY,THEREBASICCONCEPTSAREAVAILABLEFORSHIFTINGANDSTARTINGTHEDRYCLUTCH；THEWETCLUTCH；THETORQUECONVERTER；THEDRYCLUTCHISKNOWNFORITSVERYGOODEFFICIENCY；ITSGOODCONTROLLABILITY；ITSDRAGTORQUE–FREEFEATUREITSRELATIVELYSMALLMASSMOMENTOFINERTIATHEVERYGOODEFFICIENCYOFTHENORMALLYCLOSEDDRYCLUTCHISDUETOTHEABSENCEOFAUXILIARYPOWEROTHERSOLUTIONSALWAYSNEEDPRESSUREANDTHUSADDITIONALPOWERINTHEBRIDGEDORCLOSEDCONDITIONWETCLUTCHADVANTAGEARELITTLEMASS；VERYSMALLMASSMOMENTOFINERTIA；VERYGOODCONTROLLABILITY；HIGHPOWERDENSITYANDGREATTORQUECAPACITYTHEWETCLUTCHISTHEREFOREOPTIMALLYSUITEDFORVEHICLESWITHSMALLINSTALLATIONSPACEANDVERYHIGHTORQUELEVELSDUETOITSFUNCTIONASAHYDRODYNAMICHYDRAULICTRANSMISSION,THETORQUECONVERTERWITHORWITHOUTSLIPCONTROLLEDLOCKUPCLUTCHANDTORSIONALVIBRATIONDAMPEROFFERSEFFICIENCYADVANTAGESINTHENONBRIDGEDCONDITIONANDANDATORQUETRANSLATEDBYTHEHYDRAULICTRANSMISSIONASWELLASOVERLOADPROTECTION目前的传动系概念1发动机的发展汽油和柴油发动机是目前主要的驱动元件，混合驱动和燃料电池仍处于设计开发阶段尚未占领市场。新型的喷射技术，如共轨泵喷射，通常被应用于柴油发动机。它大幅度降低了油耗并由于提高了发动机的转矩和性能改善了动态传动特性。目前多点直接喷射广泛应用于汽油发动机。为了满足苛刻的排放法规，欧洲议会和欧洲汽车工业协会要求在2008年将新注册的轿车的CO2排放量在1995年水平上降低25，这需要在近几年内明显降低车辆的能耗和排放，这导致了汽油发动机用传动系的多样化。直接喷射系统将通过减少排量，发动机增压、机电一体化或机械式阀门配气机构系统及他们的组合占领部分市场。采用分层进气或容积效率控制的汽油机多气门技术和是发动机工作在高效率区的负荷循环换挡概念将是全分离节气门汽油发动机今后几十年的两大主要技术。小型化和发动机增压技术在未来几年内将明显提高发动机最大转矩的水平。2变速器类型手动变速器（MT）和自动变速器（AT）是目前变速器市场的主要产品，几年前市场上开始出现机械自动变速器（AMT）和无级变速器（CVT），但它们仅占有极小的市场份额。手动变速器便宜，体积较小、并且圆柱齿轮组的效率很高，能耗主要取决于驾驶员的换挡技术和车辆形式。自动变速器的舒适性体现在自动换挡和离合器的自动工作上，教多的挡位及相应增加的间距也改善了舒适性，效率高、重量合适和成本底是该类变速器生存的要点。换挡时存在的牵引力中断现象对舒适性有影响，将来的AMT可通过采用优化换挡措施减少之。有两根对立变速器输入轴的双离合器动力换挡变速器是AMT的一个发展方向，它在变速器的无负荷部分进行预换挡，通过控制第一和第二离合器上的转矩转移实现所挂挡位的加载过程。