780961 PowerTrainSelection for OptimumPerformance and Efficiency J.W.SchmidtandR.L.Kesler DetroitDieselAllison DivisionofGeneralMotorsCorporation International Fuels&Lubricants Meeting RoyalYork,Toronto November13-16,1978 Downloaded from SAE International by University of Auckland, Saturday, August 18, 2018Theappearance ofthecodeatthebottomofthefirstpageofthispaperindicates SAE'sconsentthatcopiesofthepapermaybemadeforpersonalorinternaluse,or forthepersonalorinternaluseofspecificclients.Thisconsentisgivenonthecon dition,however,thatthecopierpaythestatedperarticlecopyfeethroughthe CopyrightClearance Center,Inc.,Operations Center,P.O.Box765,Schenectady, N.Y.12301,forcopyingbeyondthatpermittedbySections107or108oftheU.S. Copyright Law.Thisconsentdoesnotextendtootherkindsofcopyingsuchas copyingforgeneraldistribution, foradvertising orpromotional purposes, for creatingnewcollective works,orforresale. Paperspublishedpriorto1978mayalsobecopiedataperpaperfeeof$2.50 undertheabovestatedconditions. SAEroutinelystocksprintedpapersforaperiodofthreeyearsfollowingdateof publication. DirectyourorderstoSAEOrderDepartment. Toobtainquantityreprintrates,permission toreprintatechnicalpaperorper mission to usecopyrighted SAEpublications inotherworks,contacttheSAE Publications Division. ISSN0148-7191 Copyright ©1978SocietyofAutomotive Engineers, Inc. Downloaded from SAE International by University of Auckland, Saturday, August 18, 2018780961 PowerTrainSelection for OptimumPerformance and Efficiency J.W.SchmidtandR.L.Kesler DetroitDieselAllison DivisionofGeneralMotorsCorporation INTHELAST25YEARS,theemphasisincom mercialtransportservicehasshiftedfromrailto road.Asaresultofthisshift,vehicleownershave beenconfronted withtheproblemofoperatingin creasingly sophisticated, heavier,fastervehicles overmoredemanding dutycycles.Theowners' problemhasbeencompounded byashortageof skilleddriversandbythepressureofcostsoutrun ningearnings. Since1956,manycommercial vehicleowners havesolvedpartoftheirproblembyinstallingthe Allisonautomatic transmission tomakethelesser skilleddrivermoreproductive and,thus,more profitable. Onthebasisoftheexperience gained withthefirstgeneration automatic transmission, production oftheAT-540,thefirstofafamilyof automatic transmissions fortheentirecommercial vehicleindustry(seeFigure1),wasbegunin1970. Thesuccessofthefamily,asmeasuredbygreateracceptance inexistingmarketsandsignificant penetration intonewmarkets,furtherconfirmsthe factthattheautomatic transmission hasbeen satisfyingthecommercial vehiclemarket'schang ingandincreasingly diverserequirements tothe economicbenefitoftheowner. Duetothecurrentenergycrisis,spiralingwages andinflation,fleetownersareagainassessingtheir totalvehiclecosts.GeneralMotorshasbecomein volvedinthiseffortbysupporting theIn dustry/Government VoluntaryTruckandBusFuel Economy Improvement Program. Inaddition, GeneralMotorsandDDAareinvolvedinthe DOT/SAETruckandBusFuelEconomyMeasure mentProgram. Theassessment ofoverallvehiclecosts necessarily includestheevaluation ofeachin dividualcomponent. Asacomponent manufac turer,DDAissensitivetotheneedforsuchsystem ABSTRACT Today'scommercial transport servicevehicle ownerisbeingconfronted withincreasingly com plexproblemsinhisvehicleoperation. Asameans ofsolvingoneofhisproblems,methodsofevalua tingpowertraincomponents andtheireffecton obtainingoptimumvehicleperformance andeffi ciencyhavebeendeveloped. Vehiclevocationvariablesandthedifferenttypesofpowertrainsand powercomponents havebeenanalyzed. Utilization ofthetechniques describedshould bringthevehicleengineerclosertoprovidingan optimummatchofvehicle,engine,transmission, axle,andtiresforagivenvocation. 0148-7191/78/1113-0961$02.50 Copyright ©1978SocietyofAutomotive Engineers, Inc. New TextDownloaded from SAE International by University of Auckland, Saturday, August 18, 20182 analysis,particularly withrespecttopowertrain components. Thispaperwillcovertheevaluation of powertraincomponents andtheireffectonobtain ingoptimumvehiclepe