Mahle_Cam_Timing

InvestigationofPotentialFuelEconomyImprovementsofaSOHCEngineviaIndependentInletandExhaustCamTimingControlg2008GT-SUITEConferenceMikeBassett,SteveSimmonds,DavidGurney,RobLynnHughBlaxillRobLynn,HughBlaxillMAHLEPowertrain,UKFalkSchneider©MAHLEMAHLEValvetrain,GermanyContentContent„Introduction„MAHLECamInCam®SystemOverview„MAHLECamInCam®SystemOverview„BaselineEngineTesting„EngineSimulation–BaselineModelCorrelation–CamInCam®WOTPerformanceOptimisation–CamInCam®PartLoadFuelConsumptionOptimisation„CamTimingSelectionandCamPhaserConsiderations„CamInCam®EngineTesting–ComparisonwithEngineModellingResultsComparisonwithEngineModellingResults„VehiclePerformance„Conclusions2MAHLEPowertrainLtd.,14-October-2008©MAHLEIntroductionIntroduction„Fueleconomylegislationfornewvehiclefleetsdemandshighengineefficiency„VariableValveTiming(VVT)allowssimultaneousimprovements„VariableValveTiming(VVT)allowssimultaneousimprovements–WideOpenThrottle(WOT)–PartLoadFuelEconomyandEmissionsCombustionstability–Combustionstability„TraditionallyVVTisachievedwithcamshaftphasers–Independentphasingofinletandexhaustvalvesreadilyachievedfordoubleoverheadcamshaft(DOHC)enginescamshaft(DOHC)engines–2-valvepercylindersingleoverheadcamshaft(SOHC)oroverheadvalve(OHV)enginesƒAdvantagesofcostandpackagingƒSinglecamshaftenginelimitedtodualequalphasingonlyƒSinglecamshaftenginelimitedtodualequalphasingonly„Newmechanicaldevice–CamInCam®–Allowsinletonly,exhaustonlyordualindependentVVTonasinglecamengineThikdibthlitifthditESOHCi3MAHLEPowertrainLtd.,14-October-2008©MAHLE–ThisworkdescribestheapplicationofthedevicetoaEuropeanSOHCengineMAHLECamInCam®SystemMAHLECamInCamSystem„ExhaustLobespermanentlyfixedtoExhaustCamLobesSlotsforInletPinspyoutertube(1)„Inletlobesfixedtoconcentricinnershaft(2)withpins(3)21ExhaustCamLobes22CamshaftBearingSlottedTbe3InletCamLobesSlottedTubeMoveableCamLobe„OnceassembledInletlobeshaveslidingfitoveroutershaftFixedCamLobe4MAHLEPowertrainLtd.,14-October-2008©MAHLE„ManufacturesimilartoconventionalassembledcamshaftsFixedCamLobeInnerShaftPinBaselineTestingBaselineTesting„Europeanproductionengine„IndicatingmeasurementsTestEngineDetails„Indicatingmeasurements–Watercooledcylinderpressuresensors(Kistler6041type)–Highspeedinlet/exhaustpressuresCapacity/Layout1.2L/4cylsInlineValvetrain8v,SOHC,DirectactingCompressionRatio9.8:1224°(TopofRamps)gpp„WideOpenThrottle(WOT)testing–manualAFR&ignitiontimingoptimisationIn/ExhCamProfile8mmpeakliftValveTimingIMOP108.5°ATDCNFEMOP110.5°BTDCNFVariableCamPhasingFixedInlet/FuelFixedInlet/MPI„PartLoad–TestPointsselectedfromvehicledrivecycleInlet/FuelFixedInlet,/MPIExhaustManifold4into2into1ExternalEGRNo–WarmandColdidletestedforstability„ChargeDilutionTolerance–InletairsampledforCO2dilutionintheinletrunners5MAHLEPowertrainLtd.,14-October-2008©MAHLEPartLoadTestPointSelectionPartLoadTestPointSelectionPartLoadTestPointsTestPointSpeedBMEP()(kP)100(rpm)(kPa)3rdhill2500150100km/hCruise3000500WWMappoint15002626080ure[kPa]120km/hppWWMappoint20002004060ManifoldPressu3rdHillIdle70km/h100km/h020M1stHill2ndHillIdle50km/h6MAHLEPowertrainLtd.,14-October-2008©MAHLE01000200030004000EngineSpeed[rev/min]ResidualGasFractionDilutionToleranceResidualGasFractionDilutionTolerance„TolerancetoResidualGasFraction(RGF)haslargeinfluenceonfuelconsumption„Forenginesimulation,combustionstabilityassumedproportionaltoRGFForenginesimulation,combustionstabilityassumedproportionaltoRGF–Ignoreseffectsofchargemotionandeffectivecompressionratio–Goodcorrelationreportedbyothers„Baselineengineonlyavailablewithfixedcamtiming„Baselineengineonlyavailablewithfixedcamtiming–EffectofRGFwasreplicatedbyadditionofCO2intoinletsystem–Inletairsampledininletrunnerfordilutionmeasurement„MaximumCOtolerancewasdefinedfor015barSDIMEP„MaximumCO2tolerancewasdefinedfor0.15barSDIMEP–InternalRGFcalculatedwithenginesimulation–GivesanestimateforacceptabletotalRGFlimitSpeedLoadCalculatedRGFMeasuredmaximumCO2Maximumtrappedresiduals(rev/min)(kPa)(%)(%)(%)30005006.912.018.02500150123701847MAHLEPowertrainLtd.,14-October-2008©MAHLE250015012.37.018.4200020011.78.519.2150026211.513.023.0BaselineGT-PowerModelCorrelationatWOTBaselineGTPowerModelCorrelationatWOT()()()100110890bar]60rque[Nm]8090100efficiency[%]758085derpressure[455055Braketo6070MeasuredGT-PowermodelVolumetric6570aximumcylind3540„Wiebecombstionmodelsedithmeasredphasing(50%MFB)anddration(1050Enginespeed[rev/min]100020003000400050006000GT-Powermodel60Enginespeed[rev/min]100020003000400050006000M30Enginespeed[rev/min]100020003000400050006000„Wiebecombustionmodelusedwithmeasuredphasing(50%MFB)andduration(10-90%MFB)data–Maximumcylinderpressureindicatescombustioniswellmodeled„Torquecorrelationwithin3%8MAHLEPowertrainLtd.,14-October-2008©MAHLE„Torquecorrelationwithin3%„VolumetricEfficiencywithin4%BaselineModelCorrelation-WOTBaselineModelCorrelationWOT„Pressurewaveactivityintheinletrunnerwellmodeled1.10InletRunnerPressure-2500rpmre[bar]1.001.05Pressu0.900.95MeasuredGTPdl0.85Crankangle[°CA]090180270360450540630720GT-PowermodelTDCfiring9MAHLEPowertrai