electro-hydraulic-control-system-for-aisin-aw-new-

400CommonwealthDrive,Warrendale,PA15096-0001U.S.A.Tel:[phone]Fax:[phone]Web::Transmission&DrivelineSymposium2004(SP-1817)2004SAEWorldCongressDetroit,MichiganMarch8-11,2004Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmitted,inanyformorbyanymeans,electronic,mechanical,photocopying,recording,orotherwise,withoutthepriorwrittenpermissionofSAE.Forpermissionandlicensingrequestscontact:SAEPermissions400CommonwealthDriveWarrendale,PA15096-0001-USAEmail:[e-mail]:724-772-4891Tel:[phone]Formultipleprintcopiescontact:SAECustomerServiceTel:877-606-7323(insideUSAandCanada)Tel:[phone](outsideUSA)Fax:[phone]Email:[e-mail]0-7680-1319-4Copyright©2004SAEInternationalPositionsandopinionsadvancedinthispaperarethoseoftheauthor(s)andnotnecessarilythoseofSAE.Theauthorissolelyresponsibleforthecontentofthepaper.AprocessisavailablebywhichdiscussionswillbeprintedwiththepaperifitispublishedinSAETransactions.PersonswishingtosubmitpaperstobeconsideredforpresentationorpublicationbySAEshouldsendthemanuscriptora300wordabstractofaproposedmanuscriptto:Secretary,EngineeringMeetingsBoard,SAE.PrintedinUSA2004-01-1638Electro-HydraulicControlSystemforAISINAWNew6-SpeedAutomaticTransmissionHiroshiTsutsui,TakayukiHisano,AkitomoSuzuki,MakotoHijikataandMasatoshiTaguchiAisinAWCo.,Ltd.KoichiKojimaAWTCEuropes.a.WolfsburgOfficeCopyright©2004SAEInternationalABSTRACTRecently,5-speedautomatictransmissionshavebecomemainstreamthroughtheworld,and6-speedautomatictransmissionshavealsobeenintroducedinthemarket.Consequently,theissueofshiftcontrolisgainingimportance,andatrendtowardincreasingnumberofgearsinautomatictransmissionshasbecomeapparent.Ontheotherhand,weightsavinganddownsizingofthetransmission,includingthehydrauliccontrolunit,arestronglyrequiredinordertopromotefuelefficiency.Tomeettheserequirements,anelectro-hydrauliccontrolunitofferingsophisticatedfunctionalitydesiredinordertoprovideexcellentshiftquality.AsananswertotheserequirementsAISINAWdevelopedtwotypesofnew6-speedautomatictransmissionsin2002:“TR-60SN”forRWDvehiclesand“TF-60SN”forFWDvehicles.BothTR-60SNandTF-60SNhavethesamestructuralcharacteristics.Forthecontrolstrategyofthesenewautomatictransmissions,anadvancedelectro-hydrauliccontrolsystemhasbeendevelopedthatcanensurebothone-stepshiftingandskipshiftingbymakinguseofthecharacteristicsofthisuniquegeartrainstructure.Flexibleshiftingcanberealizedbycontrollingeachclutchpressurebytherespectivelinearsolenoids,incombinationwithuseoftheelectriccontrolunit.Additionally,Lock-upcontrolandNeutralcontrolisincorporatedinthesystemtoimprovefuelefficiency.INTRODUCTIONAISINAWdevelopeda5-speedautomatictransmission“55-50SN”in1998(1)*inordertorespondtothehighexpectationsintheworldwidemarketforfuelefficiencyanddrivabilityimprovementofautomatictransmissions.Furthermore,6-speedautomatictransmissions,TF-60SNandTR-60SN,havebeendevelopedtoofferenhancedcapacityabovethatoftheexisting5-speedautomatictransmissions.Anewelectro-hydrauliccontrolunitwasdesignedtoassistthesetransmissionsinimproving“drivability”and“smoothnessofshiftquality”.Withthemultiplespeedsofthe6-speedtransmission,thedriverisliabletofeelthatshiftingis“toobusy”duetothehighfrequencyofshifting.Todealwiththis,TF-60SNandTR-60SNenablemultipleshift“skip-shift”suchasupshiftfrom2ndto4thand4thto6thordownshiftfrom6thto4thand4thto2nd,basedontheabilityofeachlinearsolenoidtocontroltheengagementandreleaseoftherespectiveclutchseparately.Inaddition,fourlinearsolenoidscontrolfourengagementelements,whichensuresdownshiftfrom6thto3rdand5thto2nd.This“skip-shift”reducesthefrequencyofshifting,whichdependsonthedrivingcondition,andensuresgood“drivability”.Thenumberofswitchvalveswaslessenedandminimizationinsizewasachievedbycontrollingeachengagementelementdirectlywithanindividuallinearsolenoid.Tomeetshiftfeelrequirements,weminimizedtheeffectofproductionvariationsbyadjustingthecontrolpressureoftheengagementelementsonebyone.Duringshifting,eachengagementelementisdirectlycontrolledbythelinearsolenoidandcompensationisexecutedusingfeedbackcontrolandself-learningcontrol.Thisreducestheeffectofproductionvariationsandminimizestheinfluenceofdegradationathighmileage.TF-60SNandTR-60SNutilizethesameconceptfortheoilpressurecircuitunitandapplythesamesoftwarefortransmissioncontrol.Thishasenabledustodevelopthecircuitinashortperiod,andhasalsoallowedsimultaneousintroductiontoseveralapplications.Thispaperdescribesthedesignobjectivesandthemajorfeaturesofthiselectro-hydrauliccontrolsystemforthenew6-speedautomatictransmissions.DEVELOPMENTOBJECTIVESTheelectro-hydraulicunithasbeendevelopedforthefollowingpurposes:DRIVABILITYToperformskip-shiftandprevent“busy-shifting”inordertotakefulladvantageofthe6-speeds.COMPACT