Modelling of the Intake Manifold Filling Dynamics_

SAESAE400CommonwealthDrive,Warrendale,PA15096-0001U.S.A.Tel:[phone]Fax:[phone]TheEngineeringSocietyForAdvancingMobilityLandSeaAirandSpaceINTERNATIONAL®InternationalCongressandExpositionDetroit,MichiganFebruary26-29,1996ModellingoftheIntakeManifoldFillingDynamicsElbertHendricks,AlainChevalier,MichaelJensen,andSpencerC.SorensonTechnicalUniversityofDenmarkDaveTrumpyandJoeAsikFordMotorCo.Reprintedfrom:ElectronicEngineControls1996(SP-1149)SAETECHNICALPAPERSERIES960037Nopartofthispublicationmaybereproducedinanyform,inanelectronicretrievalsystemorotherwise,wfthoutthepriorwrittenpermissionofthepublisher.ISSN0148-7191Copyright1996SocietyofAutomotiveEngineers,Inc.Positionsandopinionsadvancedinthispaperarethoseoftheauthor(s)andnotnecessarilythoseofSAE.Theauthorissolelyresponsibleforthecontentofthepaper.AprocessisavailablebywhichdiscussionswillbeprintedwiththepaperifitispublishedinSAETransactions.Forpermissiontopublishthispaperinfullorinpart,contacttheSAEPublicationsGroup.PersonswishingtosubmitpaperstobeconsideredforpresentationorpublicationthroughSAEshouldsendthemanuscriptora300wordabstractofaproposedmanuscriptto:Secretary,EngineeringMeetingsBoard,SAE.PrintedinUSA96-0049TheappearanceoftheISSNcodeatthebottomofthispageindicatesSAE'sconsentthatcopiesofthepapermaybemadeforpersonalorinternaluseofspecificclients.Thisconsentisgivenontheconditionhowever,thatthecopierpaya$7.00perarticlecopyfeethroughtheCopyrightClearanceCenter,Inc.OperationsCenter,222FlosewoodDrive,Danvers,MA01923forcopyingbeyondthatpermittedbySections107or108ofU.S.CopyrightLaw.Thisconsentdoesnotextendtootherkindsofcopyingsuchascopyingforgeneraldistribution,foradvertisingorpromotionalpurposes,forcreatingnewcollectiveworks,orforresale.SAEroutinelystocksprintedpapersforaperiodofthreeyearsfollowingdateofpublication.DirectyourorderstoSAECustomerSalesandSatisfactionDepartment.QuantityreprintratescanbeobtainedfromtheCustomerSalesandSatisfactionDepartment.TorequestpermissiontoreprintatechnicalpaperorpermissiontousecopyrightedSAEpublicationsinotherworks,contacttheSAEPublicationsGroup.GLOBALMOBILITYDATABASEAllSAEpapers,standards,andselectedbooksareabstractedandindexedintheSAEGlobalMobilityDatabase.960037ModellingoftheIntakeManifoldFillingDynamicsElbertHendricks,AlainChevalier,MichaelJensen,andSpencerC.SorensonTechnicalUniversityofDenmarkDaveTrumpyandJoeAsikFordMotorCo.Copyright1996SocietyofAutomotiveEngineers,Inc.ABSTRACTMeanValueEngineModels(MVEMs)aredynamicmodelswhichdescribedynamicenginevariable(orstate)responsesasmeanratherthaninstantaneousvaluesontimescalesslightlylongerthananengineevent.Suchenginevariablesaretheindependentvariablesinnonlineardifferential(orstate)equationswhichcanbequitecompactbutneverthelessquiteaccurate.Oneofthemostimportantofthedifferentialequationsforasparkignition(SI)engineistheintakemanifoldfilling(oftenmanifoldpressure)stateequation.ThisequationiscommonlyusedtoestimatetheairmassflowtoanSIengineduringfastthrottleangletransientstoinsureproperenginefueling.Thepurposeofthispaperistoderiveamodifiedmanifoldpressurestateequationwhichissimplerandmorephysicalthanthosecurrentlyfoundintheliterature.ThisnewformulationmakesiteasiertocalibrateaMVEMfordifferentenginesandprovidesnewinsightsintodynamicSIengineoperation.ThenewmodelalsoprovidesinformationusefulforEGRcontrol.1.INTRODUCTIONMeanValueEngineModels(MVEMs)havecometobeanacceptedmethodofdescribingthedynamicbehaviorofsparkignition(SI)engines.MVEMsmodelsdescribethetimedevelopmentofthemostimportantmeasurableenginevariables(orstates)ontimescalesalittlelargerthananenginecycle[1],[2].ThestatesofanSIengineareusuallythefuelfilmflowormass,thecrankshaftspeedandthemanifoldpressure,eachdescribedwithadifferentialequationdrivenbyacontrolinput:thesearetheinjectedfuelflow,thesparkadvanceandthethrottleanglerespectively.Forsimulationandcontrolpurposes,oneofthemostimportantpartsofsuchmodelsisthemanifoldpressurestateequation.Thisisbecausethemanifoldpressurestateequationcanbeusedtopredicttheinstantaneousmeanairmassflowtoanengineincludingtheeffectofthefillingoremptyingoftheintakemanifoldwithairduringthrottleopeningorclosing.ThisisofcourseofcriticalimportancebecauseSIenginesandtheiremissionsaresosensitivetotheinstantaneousair/fuel(A/F)ratioatwhichtheyoperate.Thatthismodelequationisimportantisattestedtobythelargenumberofdifferentversionsofthiskindofmodelwhichexistandaredocumentedintheliterature,[2],[3],[4],[5],[6],[7],[8].InparticulartheManifoldPressureStateEquation(MPSE)hasprovedtobeofgreatuseinA/Fratiocontrolapplications.Thusithasbeenusedinbothconventional[4],[9],[10],[11]andsecondgeneration[12]andadvancednonlinearcontrolsystemsfortransientA/Fratiocontrolapplicationsforbothopen[13],[14],[15]andclosedloop[16],[17]controlschemes.TheMPSEisalsoofimportanceinthedesignofnonlinearcontrolsforidlespeed[18],[19]andoverallvehiclecontrol[20].ItisclearthattheultimateaccuracyandpracticalusefulnessofsuchschemesisstronglydependentontheaccuracyoftheMPSEandtheeaseandspeedwithwhichitcanbecalibratedtoagivenengine.Earlierworkwithmo