輕型車轉(zhuǎn)鼓試驗循環(huán)分析教材

LightDutyVehicle&PassengerCarChassisDynoTestLoadAnalysisChenPPengAgendaBackgroundAEB21.52specification.LDVCoolingsystemSeverestEnvironmentFactorsEnginedutycycledesign.Vehicleoverpayload.Vehiclerunonseverestgraderoad.Runathighambienttemperature.Airconditioneropenandaccessorycomponentsrun.FandrivecontrolThermostatrangeCoolantheatcapacityandsystemdaerationTransmissionoperationDutycycleforchassisdynoIQAtest.2024/6/42CumminsConfidentialBackgroundForIQAtest,wefollowtheAEB21.52totestcoolingandCACsystemfortrucksandBuses.WetestvehicleatratedtorqueandratedpowerdutycycletovalidatethecoolingandCACapplicationdesign.WearechallengedbyOEMandcustomerwhenwetestthepassengervehicleandlightdutyvehicles.ThepointfromOEMisthatthepassengervehiclesandlightdutyvehiclesalmostneverrunatratedfullload,whywetestvehiclecoolingsystematHighload.Thistopicistryingtofindtherealmaximumloadforpassengervehiclesandthelightdutyvehicles,andattemptfindawaytoaimadutycycleforLDonchassisdynotest.2024/6/43CumminsConfidentialAEB21.52specificationforCoolingSystemtest.2024/6/44CumminsConfidentialAEB21.52specificationforCoolingSystemtest.2024/6/45CumminsConfidentialAEB21.52specificationforCoolingSystemtest.TheTTDmeasuredatmaximumloadisreprehensivecoolingsystemcapabilityofthevehicle.TheTTDisconstantlywhenambienttemperature15-43DegC,So,TTDiscalledCoolingConstantFactorbysomeOEM.TTDmaximumlimitdependontheareavehiclewillrun.2024/6/46CumminsConfidentialAEB21.52specificationforCoolingSystemtest.TheTTDisinconstantwhenenginestablerunbutrisingTcoolantandTambient2024/6/47CumminsConfidentialLDVCoolingsystemSeverestEnvironmentsFactorsThevehiclecoolingsystemseverestenvironmentsshouldbesimulatedatchassisdynotestortowdynotestforvalidatecoolingsystemdesign.Theconsideredfactorshouldbebelow.Enginedutycycledesign.Vehicleoverpayload.Vehiclerunonseverestroad.Runathighambienttemperature.Airconditioneropenandaccessorycomponentsrun.FandrivecontrolThermostatrangeCoolantheatcapacityandsystemdaerationTransmissionoperation2024/6/48CumminsConfidentialEngineDutyCycleDesignEnginedutycyclebaseonpowertraindesignandthedriveroperation.Enginerunatlowerspeedandhighershiftwillgetenginemorepossibleclosetofullload.Mostenginedesignedrunmosttimeattoptorquespeedinsteadofmaximumspeed.Enginetorquespeedismoreimportantthanmaximumspeedforsystemvalidationtest.2024/6/49CumminsConfidentialVehicleoverpayloadAvalonengineonDAFFALF45rapidtruckdidaoverloadtestfordutycyclelogging.Thetruckloadisonspecification.ItsGWis7tons.Theoverloadrealizedbytowanothervehicle.ThedualvehiclesGVWis16,20,25tons.Itsoverloadis125%,185%and250%.Thedutycycleisloggedasruntimevs.enginetorqueandspeed.ShiyanSuizhouXiaoganGuchengLaohekouZaoyang2024/6/410CumminsConfidentialVehicleoverpayloadRightfigureisengineruntimevsenginespeedandengineTorque.AisthevehicleVGW7tonswith125kw/2600rpmengineatfullloadonhighway.Bisthesamevehicle125%overloadrunatsamehighway.AB2024/6/411CumminsConfidentialVehicleoverpayloadContinuouslyCis185%overloadrunatsamehighway.Dis250%overloadatsamehighway.Theoverloadresulttheenginerunat50%between80%ofratedspeedrun.Veryfewrunatmaximumspeed.CD2024/6/412CumminsConfidentialVehicleoverpayloadOverloadhappenedfrequently,heavily.Overloadlimitedbytransportlegalregulation.Startabilitywillbeimpactedbyoverloadphysically.Theoverloadlimitedbyitstart.Overload,willmakethevehiclespeedlowerthannormal.Supposeoverloadwillbe150%overloadasworstsituation.Supposetheoverloadhappenedatratedtorquespeed.2024/6/413CumminsConfidentialVehiclerunonseverestgraderoadTheseverestroadforvehicleisatmaximumgradeuphillandworstfriction.Theroadrollfrictionisdependontireperformanceandroadconstruction,thefrictioncalculatedintirelosspowerinVMSsimulation.Gradehilldependonroadconstructionspecification.Iftheroadisnotplane,vehiclecouldnotdriveinhighpowerandspeedsincetheshakeandnoise.Thegradeanddistancespecificationasnextpagetablepresents.2024/6/414CumminsConfidentialMinimumHill

distanceMaximumHilldistanceJTGB01-2003TechnicalStandardofHighWayEngineeringGradeDesignSpeedDesignSpeedMinimumHill

distance2024/6/415CumminsConfidentialMinutescovermaxhilldistancebydesignedspeedMinutescovermaxdistancebydesignedspeed以設(shè)計車速越過最大坡長需要的時間designspeed設(shè)計速度1201008060403020grade坡長

30.50.60.81.2

40.40.50.71.01.72.23.65

0.40.50.81.41.83.06

0.40.61.11.42.47

0.81.01.88

0.81.01.89

0.40.910

0.6Thecalculatedminutescoverthemaximumhilldistanceatdifferentdesignedspeedmatrix.Thehighergrade,Thelessminutesneededtodrive.Thelongerminutes,thelessgradehill.Thepossiblefullloadtoovercomebiggradehilllessthan1minutes.2024/6/416CumminsConfidentialVehiclerunonseverestgraderoadRightisatruckandavangradabilitysimulationcurve.Evendiveatmaxhighspeed,itwillnotstableandchangetotorquespeedduetothehillincreasedfrictionThemajorseverestfullloaddrivingshouldbearoundtorqueratedspeedandcontinuouslessthan1minutes.Thetestondynoshouldbeinachangingcycle.2024/6/417CumminsConfidentialRunathighambienttemperature.AEB21.52specifiedvehicleambientaslevel1to4.Highambienttemperaturewillmakeengineperformanceandcoolingsystemcapabilityweak.So,chassisdynotestshouldat20minDegCambientrun.LTAandTTDspecificationhavetobefollowed.2024/6/418CumminsConfidentialAirconditioneropenandaccessorycomponentsrunAirconditionerrunatsummerwillabsolutelyincreaseenginepoweranddecreasecoolingsystemcapability.VMSsimulationwillincludeairconditionerandotheraccessorycomponentspowerconsume.AirconditionerrunalsoeffectcoolingsystemsinceitsharefanwindwithradiatorandCAC.Airconditionershouldbeswitchonwhentestonchassisdyno.2024/6/419CumminsConfidentialFandrivecontrolForHDandMR,mostfandrivenbycrankshaftpulley,thefanspeedishighatratedpowerthanratedtorque.TTDattorquespeedislowerthanpowerspeed.ForpassengervehiclesandsomeLDV,thefanisdrivenbyalternator/battery.Thespeedisevenly.Coolingiseasieratratedtorquethanratedpowerspeed.So,thecriteriashouldbemorereasonable.TestcycleandTTDspecificationshouldnotmakeexceeddifficult..2024/6/420CumminsConfidentialThermostatrangeThermostatisdesignatedopenwhencoolingsystemneededinbestcapabilityaction.Whentestcoolingsystemonchassisdyno,thethermostatshouldbeobservedopeningbycoolanttemperatureoveropenrangeastheparametersmeasured.Ifambienttemperatureistoolowtoopenthermostat,itshouldbeopenedbymechanicalwaytoopen.2024/6/421CumminsConfidentialCoolantheatcapacityandsystemdaerationCoolantusedonenginesis50%ethyleneglycolwithwater.Theheatcapacityofethyleneglycolismuchl