&.eTheEngineering Society~ ForAdvancing Mobility~ LandSeaAirandSpace® INTERNATIONAL400COMMONWEALTH DRIVE,WARRENDALE, PA15096·0001 U.S.A. SETechnical PaperSeries 892530 ANewAllisonTransmission OutputRetarder D.Klemen, R.K.MartinandJ.L.Trotter AllisonTransmission Division GeneralMotorsCorporation TruckandBusMeeting andExposition Charlotte, NorthCarolina November 6-9,1989Downloaded from SAE International by Purdue University, Monday, August 20, 2018Theappearance oftheISSNcodeatthebottomofthispageindicatesSAE'sconsentthat copiesofthepapermaybemadeforpersonalorinternaluseofspecnicclients.Thisconsent isgivenonthecondition, however,thatthecopierpaya$5.00perarticlecopyfeethroughthe Copyright Clearance Center,Inc.,Operations Center,27Congress St.,Salem,MA01970for copyingbeyondthatpermitted bySections 107or108oftheU.S.Copyright Law.Thisconsent doesnotextendtootherkindsofcopyingsuchascopyingforgeneral distribution, for advertising orpromotional purposes, forcreatingnewcollective works,orforresale. SAEroutinelystocksprintedpapersforaperiodofthreeyearsfollowingdateofpublication. DirectyourorderstoSAECustomer ServiceDepartment. Toobtainquantllyreprintrates,permission toreprintatechnicalpaperorpermission touse copyrighted SAEpublications inotherworks,contacttheSAEPublications Group. AJISAEpapers8Ill abstmeted andindelOOin ffl&SAEGlobalMobilityDatabasB. SA!GLOBAL MOBIUTY DATABASE NopartllfthispUblication maybereproduced inanyform,inan electronic retrievalsystemorotherwise, without thepriorwrn­ tenpermission ofthepublisher. ISSN0148-7191 Copyright 1989SocietyofAutomotive engineers, Inc. Posnionsandopinionsadvanced inthispaperarethoseofthe author{s)andnotnecessarily thoseofSAE.Theauthorissolely responsible forthecontentofthepaper.Aprocessisavailable bywhichdiscussions willbeprintedwiththepaperifIIis published inSAETransactions. Forpermission topUblishthis paperinfullorinpart,contacttheSAEPublications Division.PersonswishingtosubmnpaperstobealnSidered forpresen­ tationorpublication throughSAEshouldsendthemanuscript ora300wordabstractofaproposed manuscript to:Secretary, Engineering ActivnyBoard,SAE. PrintedInUSADownloaded from SAE International by Purdue University, Monday, August 20, 2018ABSTRACT Thedemand forsecondary braking systems oncity transitbusestoextendservicebrakelininglifeisincreasing. Tosatisfythisdemand, AllisonTransmission hasdeveloped anintegraloutputretarder fortheAllisonV731transmission usedincitytransitbuseswithfutureadaptability tothe HT700transmission. Thenewretarder takesadvantage ofimproved technolo­ giestoprovidegoodresponse andlowspeedcapacity neces~ saryforthedemanding citybusvocation. Thesetechnologies alsoallowthesimplecompact configuration tofitinthere­ strictedspaceavailable inangledrivebuses. SECONDARY BRAKING SYSTEMS ORRETARDERS havebeenlegislated inmanycountries ofEuropeforseveral yearsandmarket surveys indicate increasing demand in NorthAmerica. Thecurrentworldwide desireforretarders hastwoprimary requirements basedonthevehiclevocation: fordownhill speedcontrolandforincreasing theservice brakelifeduringhighdensitystoplstart duty.Fordownhill operation, theretarder maintains thepropervehiclespeed downlongsteepmountainous gradesleaving theservice brakesinreserveforemergency stops.Forstop/start opera­ tion,theretarder isusedtoassisttheservicebrakesthereby reducing brakeliningtemperatures andextending lininglife. Whilenotlegislated inNorthAmerica, manycitytransitbus purchase specifications nowrequire retarders toincrease brakelininglifeandtoprovideasecondary brakingsystem. AllisonTransmission Division currently produces anout­ putretarder available onthein-linetransmissions usedin bothhighdensitystoplstart vehiclesandover-the-road vehi­ cles.HO\vever, duetocriticalvehiclespacelimitations, this retarder hasnotbeenfittedtotheV731transmission usedin mostNorthAmerican citytransitbuses. Thedesigu,development andinstallation ofanewout­ putretarder fortheV731transmission, whichcouldbein­ stalledinexisting vehicles without ma