ControlofCombustionTiminginHCCIEngine

工况节油司机节油车辆节油Reporter：HaipengYuTime：2016-03-17ControlofCombustionTiminginHCCIEngine1Contents2ResearchBackground1EffectsofIntakeTemponHCCIEngine2MPCforCombustionTiminginHCCI3SummaryandProspect43EmissionsregulationsandtechnologiesadoptedFig.1.EvolutionofEmissionsRegulations(USA,Heavy-dutydieselengine)1.ResearchBackground4Fig2.Diagramshowingtheoperationofa4-strokeSIengine.Labels:1‐Induction2‐Compression3‐Power4‐ExhaustFig3.Differentcombustionmodetracesontheφ-Tmap1.ResearchBackgroundNotice:HCCIisoneofthelowtemperaturecombustion(LTC)mode5HCCIcombinescharacteristicsofconventionalgasolineengineanddieselengines.Gasolineenginescombinehomogeneouscharge(HC)withsparkignition(SI),abbreviatedasHCSI.Dieselenginescombinestratifiedcharge(SC)withcompressionignition(CI),abbreviatedasSCCIHomogeneouschargecompressionignition(HCCI)isaformofinternalcombustioninwhichwell-mixedfuelandoxidizer(typicallyair)arecompressedtothepointofauto-ignition.1.1FundamentalofHCCIGasolineEngineDieselEngineHCCIHC+SISC+CISinceHCCIenginesarefuel-lean,theycanoperateatdiesel-likecompressionratios(15),thusachieving30%higherefficienciesthanconventionalSIgasolineengines.Homogeneousmixingoffuelandairleadstocleanercombustionandloweremissions.BecausepeaktemperaturesaresignificantlylowerthanintypicalSIengines,NOxlevelsarealmostnegligible.Additionally,thetechniquedoesnotproducesoot.HCCIenginescanoperateongasoline,dieselfuel,andmostalternativefuels.HCCIavoidsthrottlelosses,whichfurtherimprovesefficiency.6Achievingcoldstartcapability.Highin-cylinderpeakpressuresmaydamagetheengine.Highheatreleaseandpressureriseratescontributetoenginewear.Autoignitionisdifficulttocontrol,unliketheignitioneventinSIanddieselengines,whicharecontrolledbysparkplugsandin-cylinderfuelinjectors,respectively.HCCIengineshaveasmallpowerrange,constrainedatlowloadsbyleanflammabilitylimitsandhighloadsbyin-cylinderpressurerestrictions.Key:Controlofcombustiontimingandcombustionrate[2]AdvantagesDisadvantages1.2AdvantagesandDisadvantagesofHCCI[1]72.EffectsofIntakeTemponHCCIEngine[3]Table1Technicalspecificationsofthetestengine.Table2Thechemicalpropertiesofisooctaneandn-heptane单缸机四冲程汽油HCCI82.EffectsofIntakeTemponHCCIEngine[3]Fig.2.Theschematicviewoftheexperimentalsetup进气加热单缸机测功机自变量：进气温度因变量：缸内温度、缸内压力排放物、自燃正时等92.1ResultsandDiscussionFig.3.Thevariationofin-cylinderpressureandheatreleaserateatdifferentintakeairtemperatures.102.1ResultsandDiscussionFig.4.Theeffectsofintakeairtemperatureonthevariationofin-cylindertemperaturewithcrankangle.11Fig.5.NormalizedcumulativeheatreleaseofHCCIcombustionatdifferentintakeairtemperatures2.1ResultsandDiscussion12Fig.6.Theeffectsofintakeairtemperatureonbraketorqueandspecificfuelconsumption.2.1ResultsandDiscussionwhere,σimepisdefinedasthestandardeviationofindicatedmeaneffectivepressureof50consecutivecycles.Xisdefinedastheaverageofindicatedmeaneffectivepressure.Fig.7.Cyclicvariationsofindicatedmeaneffectivepressurewithintakeairtemperature133.MPCforCombustionTiminginHCCIPlantPlantPIDF(s)Fig.8.1传统PID控制模式Fig.8.2MPC控制模式143.MPCforCombustionTiminginHCCI控制对象机理模型DPM控制模型COM验证标定模型设计控制器调试控制器验证控制器数学物理降阶实验数据离散化标定参数修正参数153.MPCforCombustionTiminginHCCI[4]压力升高，残余废气加热，提升气体温度Fig.9.1SymmetricnegativevalveoverlapstrategyFig.9.2HCCIenginepressuretracewith160CANVOduration-obtainedfromDPM创新点：163.MPCforCombustionTiminginHCCIDPM简化DPMCOM173.ControllerStructureforCombustionTimingMPCHCCIEngineEVCFuelingrateOtherModuleTorqueCA50TorqueCA50Fig.10.MPCcontrollerforcombustioninHCCIengine18Fig.11.Controllerperformanceconsideringmeasurementnoise:(a)&(b)controlleroutputs(c)&(d)systemoutputs(e)fuelequivalenceratio[ω=825RPM,Pint=95kPaandTint=80°C]因传感器实际采集的信号伴随干扰噪声所以仿真时对输入信号进行噪声干扰测试3.2PerformanceofMPCController1)In-cylinderpressureandheatreleaserateincreasedwiththeincreaseofintaketemperature.2)Theexperimentsshowedthathighintakeairtemperaturesincreasedthein-cylindergastemperatureattheendofthecompressionstrokeandacceleratedthechemicalreactions.3)IgnitiontimingwasinfluencedconsiderablybytheintaketemperatureinHCCIcombustionthatwasadvancedwiththeincreaseofintakeairtemperature.4)Itwasseenthatbraketorquedecreasedasintakeairtemperaturewasheatedathightemperatures.5)ThenonlinearmodelshowsacceptableaccuracyinpredictingHCCIcombustiontimingandload.6)TheMPCshowsgoodperformanceforcombustiontimingandloadcontrolinHCCIengineusingadetailedphysicalmodelfortheengine.194.SummeryandProspect1)第一篇文献只是研究了进气温度对汽油HCCI单缸机性能的影响。能否推广到其他燃料HCCI?或多缸机？2)第二篇文献只是从仿真上证明了其设计的MPC控制器性能很好，缺乏实验验证。Summery评价与体会20Mercedes-BenzF700ConceptCarDiesOtto1.8T直4CGI直喷发动机输出功率:238hp，最大扭矩:400N.m相当于一辆3.5LV6汽油耗仅为6L/100km，CO2排放127g/100kmGMSaturnAura2.2LL4汽油机的油耗仅为4.3L/100km，比常规技术降低15%以上4.SummeryandProspect[5][1]Wikipedia[2]《内燃机学》周龙保2012.01第三版P134[3]《Effectsofintakeairtemperatureoncombustion,performanceandemissioncharacteristicsofaHCCIenginefueledwiththeblendsof20%n-heptaneand80%isooctanefuels》author：CanCinarScience2015[4]《ModelPredictiveControlforCombustionTimingandLoadControlinHCCIEngines》author：KhashayarEbrahimiandCharlesKo