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Experimental Fluid Mechanics SeriesEditors Prof.R.J.Adrian Prof.M.Gharib Dept.ofMechanicalandAerospace CaliforniaInstituteofTechnology Engineering GraduateAeronauticalLaboratories ECG346 1200E.CaliforniaBlvd. P.O.Box876106 MC205-45 Tempe,AZ85287-6106 Pasadena,CA91125 USA USA Prof.Dr.W.Merzkirch Prof.Dr.D.Rockwell Universita¨tEssen LehighUniversity Lehrstuhlfu¨rStro¨mungslehre Dept.ofMechanicalEngineeringandMechanics Schu¨tzenbahn70 PackardLab. 45141Essen 19MemorialDriveWest Germany Bethlehem,PA18015-3085 USA Prof.J.H.Whitelaw ImperialCollege Dept.ofMechanicalEngineering ExhibitionRoad LondonSW72BX UK · C. Arcoumanis T. Kamimoto Editors Flow and Combustion in Reciprocating Engines 123 Prof.C.Arcoumanis Prof.T.Kamimoto CityUniversityLondon TokaiUniversity SchoolofEngineering& Dept.ofMechanicalEngineering MathematicalSciences 1117Kitakaname NorthamptonSquare Hiratsuka-shi,Kanagawa LondonEC1V0HB Japan UnitedKingdom [email protected] [email protected] ISBN:978-3-540-64142-1 e-ISBN:978-3-540-68901-0 LibraryofCongressControlNumber:2008926729 (cid:2)c 2009 Springer-VerlagBerlinHeidelberg Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialis concerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,broadcasting, reproductiononmicrofilmorinanyotherway,andstorageindatabanks.Duplicationofthispublication orpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9, 1965,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.Violationsare liabletoprosecutionundertheGermanCopyrightLaw. Theuseofgeneraldescriptivenames,registerednames,trademarks,etc.inthispublicationdoesnotimply, evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotectivelaws andregulationsandthereforefreeforgeneraluse. Coverdesign:WMXDesignGmbH,Heidelberg Printedonacid-freepaper 9 8 7 6 5 4 3 2 1 springer.com Introduction Theinternalcombustionenginefuelledbymainlygasolineanddieselhasbeenthe dominantpowerplantforwellover100years.Althoughthecontinuationofitsdom- inanceworldwidehasbeenquestionedbyenvironmentalists,whoseecarsthreaten- ingtheplanet’sclimatethroughtheeffectofCO onglobalwarming,andbysome 2 engineers who have been overoptimistic about the potential, and the timing of in- troductionoffuelcellsandelectricvehiclesintomassproduction,thereciprocating engine is here to stay for the foreseeable future. The key to its success has been its continuous re-invention into more efficient and cleaner modes of combustion, theon-goingdevelopmentandrefinementofcatalyticconvertersandthesuccessful partnershipbetweenengines,transmissionsandelectricsystems.Anotherinterest- ing development is the different approach of automotive engineers in the various continents;forexample,Europeanshaveconsistentlyputmorefaithintodieselen- gines,withover50%ofnewcarsinEuropebeingdiesels,whileJapanandtheUS havefaithfullysupportedtherelativelylessefficientgasolineenginesand,morere- cently, gasoline-hybrid vehicles which represent a reasonable compromise. There arealsootherswhobelievethatthetimehascomeforaconvergenceintheglobal markets through the introduction of the diesel hybrid vehicle but there are uncer- taintiesaboutitsabilitytoacquire‘massproduction’statusbeforefuelcellpowered andelectricvehiclesbecomeaffordablebycustomersworldwide. This volume attempts to bridge a serious gap in the existing literature between conventionaltextbookssuchasthehighlysuccessfuloneauthoredbyJohnHeywood in 1987 and the significant technological breakthroughs presented in worldwide conferences during the last ten years on direct-injection gasoline engines, ad- vanceddieselsandhomogeneous-chargecompression-ignitionengines.Themulti- authoredvolumeconsistsofeightchapterswrittenbyworldexpertsfromindustry, governmentlaboratoriesandacademia.Eachofthechaptersisself-containedand, therefore, independent from the others in that it covers its central theme in depth, andwidth,althoughpriorknowledgeofthefundamentalsremainsaprerequisite.As suchitisexpectedthatthisvolumewillbecomeanessentialreferencetextofengi- neers involved in research and development in global automotive and consultancy companies,researchengineersingovernmentlaboratoriesandacademicresearchers v vi Introduction involvedinfundamentalandappliedresearchonvariousaspectsoftheflow,mixture preparationandcombustioninreciprocatingengines. Chapter1considersthefundamentalsofspark-ignition,combustionandemis- sionsinconventionalportfuelinjectionengineswhichareintermsofnumbersthe preferred powerplant worldwide. Emphasis is placed on the characteristics of the ignitionsystem,themodelingofpremixedturbulentcombustion,initiationandde- velopmentofknockandthepollutantformationmechanisms. Chapter2describesingreatdetailtheresearchperformedoveraperiodofmore thantenyearsondirect-injection,two-strokegasolineengineswhich,despitetheir obviouspromise,neverreachedproductionintheautomotivemarket.Thischapter also provides detailed information about the various optical diagnostic techniques widely used in the research laboratories of all major automotive companies and universitieswhich,togetherwithcomputationalfluiddynamic(CFD)models,have become standard engineering tools in R&D. Although there are no two-stroke automotive engines driving road vehicles today, the research approach described in Chap.2hasbeeninstrumentalinthedevelopmentofthefour-strokedirectinjection engineswhichappearedinthemarketinthelate1990s. Chapter 3 presents in its first part an overview of the general features of the first-generationfour-strokeDIengines,theiradvantagesaswellastheirlimitations, whilethesecondpartfocusesonmorerecentresearchonthesecond-generationof stratifiedDIengineswhichareenteringproductionequippedwiththelatesttechnol- ogyofhigh-pressuregasolineinjectors.Detailsareprovidedaboutbothmulti-hole and pintle injectors operating in the spray-guided concept, and their potential for becoming standard technology is discussed in both naturally-aspirated and super- charged/turbochargedengineconfigurations. Chapter4describestheflowfieldindirect-injectiondieselenginesoperatingin thepresenceofswirl,whereparticularemphasisisplacedonthemeanandturbulent flow structure around top-dead-center (TDC) of compression as characterised by bothlaser-based-experimentsandCFDpredictions.Theimplicationsofsquishand swirl,aswellasfuelinjectiononcombustionarealsodescribedanddiscussed. Chapter5providesacomprehensiveanalysisofthepenetrationofdieselfuels, spraysandjetsunderquiescentconditions,inordertoavoidtheimplicationofswirl andmeanflow-structureonspraydevelopment,thesubsequentflameinitiationand lift-off, as well as the link between mixing-controlled fuel-vaporisation, and com- bustionunderdiesel-enginethermodynamicconditions. Chapter6complementstheprevioustwochaptersbyfocusingonauto-ignition, combustion and soot and NOx emissions in conventional diesel engines. Empha- sisisplacedonthefactorsaffectingauto-ignition,itsmodelingapproach,thesoot formationandoxidationmechanisms,aswellasthepracticalmeansforcontrolling combustioninsecond-generationdirect-injectiondieselengines. Chapter 7 presents an overview of the various types of advanced diesel com- bustionwhich,atpresent,arethesubjectofintenseinvestigationbyresearchersin bothindustryandacademia.AlthoughHCCI(homogeneouschargecompressionig- nition)isthemostwell-knownformofadvancedcombustion,itiswidelyaccepted thatpremixed, controlled-autoignition, low-temperature combustion representsthe Introduction vii most promising concept for eliminating both NOx and soot emissions in the next generationofdieselengines. Finally, Chapter 8 summarises in the first part the fuel effects on combustion andemissionsforpetroleum-basedhydrocarbonfuels(gasolineanddiesel)whilein thesecondparttheemphasisisplacedonalternativeandrenewablefuels,including syntheticfuels,thatofferpromisetobeusedinreciprocatingengines. March2008 DinosArcoumanis TakeKamimoto Contents 1 SparkIgnitionandCombustioninFour-StrokeGasolineEngines..... 1 RudolfR.MalyandRu¨digerHerweg 2 Flow, Mixture Preparation and Combustion in Direct-Injection Two-StrokeGasolineEngines..................................... 67 ToddD.FanslerandMichaelC.Drake 3 Flow, Mixture Preparation and Combustion in Four-Stroke Direct-InjectionGasolineEngines.................................137 HiromitsuAndoandConstantine(Dinos)Arcoumanis 4 Turbulent Flow Structure in Direct-Injection, Swirl-Supported DieselEngines ..................................................173 PaulC.Miles 5 RecentDevelopmentsonDieselFuelJetsUnderQuiescentConditions.257 DennisL.Siebers 6 ConventionalDieselCombustion..................................309 MakotoIkegamiandTakeyukiKamimoto 7 AdvancedDieselCombustion.....................................353 KatsuyukiOhsawaandTakeyukiKamimoto 8 FuelEffectsonEngineCombustionandEmissions..................381 ThomasRyanandRudolfR.Maly ix Chapter 1 Spark Ignition and Combustion in Four-Stroke Gasoline Engines RudolfR.MalyandRu¨digerHerweg 1.1 Introduction Today, and even more so in the future, significant and simultaneous reductions of emissionsandfuelconsumptionarethekeyissuesinenginecombustion.Sincethe S.I.engineishighlydevelopedalready,commontrialanderrormethodsalonewill nolongerbeadequatetomeetfuturerequirements.Fuelandenginepropertiesform suchacomplexsystemofmutuallyinteractingprocessesthatadetailedknowledge ofallitspropertiesisrequiredifpossibleimprovementsshallbesuccessfullyiden- tified, implemented and optimized. Therefore, a close link between practical and theoretical work is mandatory right from the start of conceiving new combustion concepts. New ideas must be complemented with adequate diagnostics to assess benefitsordrawbacksandalsowithmodels,preferablypredictiveones,forguiding andmonitoringprogress. Thischapterpresentsanoverviewonwherewearetodayandidentifieswhatwe willneedforfutureS.I.enginecombustionrequiringknowledgebothfrompractical engine work and from fundamental combustion studies. Since there is a wealth of informationavailableinbothareasitwillbeimpossibletocoveralldetailsexplicitly, andtherefore,emphasisisplacedonmaintraits.Citationswillbemadepreferablyto review-typepublicationswhenever possiblefacilitatingtracingbacktoolderwork andretrievingadditionalindepthinformationifrequired.Recommendedsourcesfor review-typeliteratureare:Heywood’stextbook[1],thejournal:ProgressinEnergy and Combustion Science, the proceedings of the Symposia (Int.) on Combustion andtheproceedingsoftheinternationalsymposiaonDiagnosticsandModelingof Combustionininternalcombustionengines(COMODIA).Thepaperfocusesonthe morefundamentalaspectssinceathoroughunderstandingoftheunderlyingphysics RudolfR.Maly Consultant Engines and Future Fuels, formerly Daimler AG, Research Division, 71065 Sindelfingen,Germany,e-mail:[email protected] Ru¨digerHerweg WorkcarriedoutatInstitutfu¨rPhysikalischeElektronik,UniversityofStuttgart,Germany, e-mail:rue [email protected] C.Arcoumanis,T.Kamimoto(eds.),FlowandCombustioninReciprocatingEngines, 1 DOI:10.1007/978-3-540-68901-0 1,(cid:2)C Springer-VerlagBerlinHeidelberg2008