~.A~TheEngineering Society~ ForAdvancing Mobility~ LandSeaAirandSpace® 400COMMONWEALTH DRIVEWARRENDALE, PA15096 rs 890833 Traction Control(TRC)Systemfor 1987ToyotaCrown KenAsami,YOshihisa NomuraandTadahisaNaganawa ToyotaMotorCorp International Congress andExposition Detroit,Michigan February27-March 3,1989Downloaded from SAE International by Imperial College London, Monday, September 24, 2018Theappearance ofthecodeatthebottomofthefirstpageofthispaperindicates SAE'sconsentthatcopiesofthepapermaybemadeforpersona! orinternl:!u$e,or forthepersonal orinternaluseofspecificclients.Thisconsentisgivenonthecon­ dition,however, thatthecopierpaythestatedperarticlecopyfeethrough the Copyright Clearance Center,Inc"Operations Center,P,O.Box765,Schenectady, N.Y.12301,forcopyingbeyondthatpermitted bySections 107or108oftheU.S. Copyright Law.Thisconsentdoesnotextendtootherkindsofcopying suchas copying forgeneral distribution, foradvertising orpromotional purposes, for creating newcollective works,orforresale. Paperspublished priorto1978mayarsobecopiedataperpaperfeeof$2.50 undertheabovestatedconditions. SAEroutinely stocksprintedpapersforaperiodofthreeyearsfollowing dateof publication. DirectyourorderstoSAEOrderDepartment. Toobtainquantityreprintrates,permission toreprintatechnical paperorper­ missiontousecopyrighted SAEpublications inotherworks.contacttheSAE Publications Division. APSAEpapersurv u/lstrDctea DIldtl1de.oo in theSAlEGlobal!'/olJll,ly D<1tab.1sc SAEGLOBAL MOBilITY DATABASE Nopartofthispublication maybereproduced inanyform,in anelectronic retrievalsystemorotherwise, without theprior writtenpermission ofthepublisher. ISSN0148-7191 Copyright ©1989societyofAutomotive Engineers,lnc. Positions andopinionsadvanced inthispaperarethoseof theauthor(s) andnotnecessarily thoseofSAE.Theauthor issolelyresponsible forthecontentofthepaper.Aprocess Isavailable bywhichdiscussions wlllbeprJntedwJththe paperJfItIspublished inSAETransactions. Forpermission topublishthispaperinfullorinpart,contacttheSAE PUblications Division.Personswishingtosubmitpaperstobeconsidered for presentation orpublication throughSAEshOUldsendthe manuscript ora300wordabstractofaproposed manus­ criptto:Secretary, Engineering ActivityBoard,SAE. PrintedinU.S.A.Downloaded from SAE International by Imperial College London, Monday, September 24, 2018890833 Traction Control(TRC)Systemfor 1987ToyotaCrown KenAsami,YoshihisaNomuraandTadahisaNaganawa ToyolaMolorCorp BASIC CONCEPT o'----"'-'-L---------- wheelSpinningTractionforcecoefficient (JLt) r-~ / ---"-"- \\TRCreference area \\Lateralforcecoefficient (p.2) \/"/""-", '--.--. Slipratio/ / / / /! ! Fig.1 -Traction andlateral force coefficients asafunction ofdriven wheelslipratio *Numbers inparentheses designate references atendofpaper.withtheABSforrear-whee I-drive vehicles, well-balanced driving ~erfor­ mance canberealized. [11,[2r Thispaperpresents anoutline and review oftheeffectiveness ofourTRC system whichapplied inToyota Crown sinceSeptember, 1987. FUNCTIONAL REQUIREMENTS -Thefunc­ tional requiremetns during acceleration onslippery roadsaregiven below. Vehicle stability oEffie"ient transmission ofdrive forcetotheroads Traction andlateral forcecoeffici­ entsareshowninFig.1asafunction of thedriven wheelslipratio. INTHERECENT TRENDofdeveloping electronic control devices forusein vehicles, thekeeping ofvehicle stabi­ lity,steerability andshortbrake distance during hardbraking issolved by meansofthenowwellknown ABS.After theintroduction ofABS,theimprovement ofvehicle stability andtraction during excessive acceleration onslippery roads became thenextimportant issue. Four-wheel-drive would beoneof goodanswers oftheissue. Although four-whee I-drive provides excellent driving performance, ithassomedisad­ vantages onweight andcosts. Thetraction control system, which controls engine torque andbrakeforce toprevent thedriven wheels from excessive spinning, isanother method. Bycombining thetraction control systemABSTRACT Excessive throttle pedalop