内燃机-替代燃料燃烧模型解决方案-2024-05-技术资料

Combustionmodellingsolutionsforalternativefuels

MOBEXWebinar

MichaelRieß,April2024

Content

Introductionandstatuscombustionmodeldevelopmentforalternativefuels

InsightIAV´shydrogencombustionmodel

ApplicationexamplesforIAV´sH2-ICEcombustionmodel

Conclusionandoutlook

Introductionandstatuscombustionmodeldevelopmentfor

alternativefuels

Ventilhub

DetailedConceptDesign

ConceptEvaluation

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2ndVirtualPrototypeLayout

540。KW720

90180270

360450

Col1

3

Combustionmodellingsolutionsforalternativefuels

OverarchingICEdevelopmentprocess

Pre-ConceptLayout

BasedonTargetsand/or

SystemLevel

outputPowertrain

ComponentLevel

Synthesis

CombustionProcess

Injector/Port…

FuelEffects

Knocking&

RawEmissions

4500

4500

4500

Simulation

Submodels

SubsystemLevel

Charging&

In-Cylinder

Flow

EAT

developedbyIAV

CombustionDesignwith

HighFidelity3DCFD

GasExchange

&Valvetrain

1stVirtualPrototypeLayout

4IAV04/2024TD-F3mrßStatus:draft,public

Combustionmodellingsolutionsforalternativefuels

Overview/selectedfuelsforICEapplications

Proprietarymodelsavailable(1D)

Developmentofmodelsongoing

Usingcommercialmodels

5IAV04/2024TD-F3mrßStatus:draft,public

SI

homogeneous

SI

stratified

CI

DFhomogeneous

CI

DFstratified

CI

DFdoublediffusive

Available/validated

Notyet

Available/validated

Notyet

Notyet

Available/validationongoing

Notyet

Workinprogress

Notyet

Notyet

Workinprogress

Notyet

Planned

Notyet

Notyet

CombustionmodellingsolutionsforalternativefuelsStatusandnextsteps

H2

CH3OH

NH3

BasicInjectionSystem

IgnitionSystem

AdvancedInjectionSystem

PilotfuelinjectionSystem

6IAV04/2024TD-F3mrßStatus:draft,public

InsightIAV´shydrogencombustionmodel

Validation/

Calibration

Parametrization

(burnrate,in/expressure)

Inalldevelopmentlevels,IAVaimsatemployingownphenomenologicalmodelsthatenablepredictive

simulationofsystem

behavior,e.g.

−Ignition

−Knock

−Flamespeed/burnrate

−Engine–outemissions

−Tailpipeemissions

Validationofassumptionsandsimulationresultson

alllevels(specific

componenttestingorin-

situexperiments)ispartofIAV´sdevelopmentprocess

SystemLevel

SubsystemLevel

Virtual

Highfidelity3DCFD

Drivingdesigniterationsforcombustionimprovement

1DSimulation

Validation

Validation

SingleCylinderEngine

Experimental

CombustionmodellingsolutionsforalternativefuelsDevelopmentprocessforH2ICE

ComponentLevel

Initial0D/1D/3DCFD

IAVH2KnockPrediction

IAVH2LaminarFlameSpeedModel

EOemissionsmodel

Validation/Calibration

H2EngineDynos

660kW/pH2≤100barpressure

bomb,RCM,vessel

combustion

spray

RapidPrototypingbymeansof3Dprint,e.g.pistonsandcylinderheads

8IAV04/2024TD-F3mrßStatus:draft,public

Combustionmodellingsolutionsforalternativefuels

IAV’sPhenomenologicalHydrogenSICombustionModel

•IAV’sH2combustionmodeldevelopedbasedondetailedchemicalkineticssimulation

•IAV’sphenomenologicalH2combustionmodelincludesdedicatedsubmodelstoconsidermostfuel-specificeffects

1.Laminarflamespeedmodel

Dedicatedapproachforhydrogenlaminarflamespeedsdevelopedbasedondetailedreactionkineticsimulationsandconsideringallrelevantboundaryconditions

(Lambdaupto4,EGRratesofupto50%,pressureofupto250barandentirerelevantunburntgastemperaturerange)

2.Auto-ignitionmodelforthepredictionofknock,capableofconsideringtheeffectofmixtureinhomogeneities

Basedonthewidely-usedLivengood-Wuintegralrepresentingthedegreeofchemicalreactionsintheunburnedmixtureresultinginknock:

C

;A,B,C=f(T,p,λ,EGR)

Parametersfittedbasedonignitiondelaytimesimulationswithdetailedreactionkinetics

Theignitiondelaytimesτarecalculatedwithahydrogen-dedicatedArrhenius-type

equation:

t=te

1=න

t=0

dt

τ=A∙e

1000T

B

IAV’sH2combustionmodeliswidelypublished,e.g.Rezaei,R.,Hayduk,C.,Fandakov,A.,Rieß,M.etal.,“NumericalandExperimentalInvestigationsofHydrogenCombustionforHeavy-DutyApplications,”SAETechnicalPaper2021-01-0522

9IAV04/2024TD-F3mrßStatus:draft,public

CombustionmodellingsolutionsforalternativefuelsValidationresultsofIAV´spremixedH2combustionmodel

FocusofIAV´sproprietaryH2combustionmodel

•H2laminarflamevelocityunderallrelevantboundaryconditions(T,p,lambda,EGR)withpcylupto250bar,lambdaupto4,EGRupto50%

•Asemi-empiricmodeltopredictresidualH2

•Akineticmodeltopredictauto-ignitionandengineknockwithboundariessimilartolaminarflamespeed

ValidationbasisonaperfectlypremixedH2-ICE

•Lambdafrom1.6…3.6,cooledEGRfrom0…30%

•Indicatedmeaneffectivepressurefrom5-22bar

•Enginespeedfrom900-1900rpm

10IAV04/2024TD-F3mrßStatus:draft,public

SimulatedSimulated

SimulatedSimulated

SimulatedSimulated

SimulatedSimulated

Prediction:Auto-IgnitionModel

3

bar

I

EP720

±5%in

bar

M

5%

T

otalEGR

Rate±5

%(relati

ve)in%

MaximumPressure±5%inbar

16

14

12

10

8

4。CA

MF

10-MFB7

BurnDu5±3。CA

rationin。CA

PredictionofAuto-Ignition

5。CA

SparkTiming±3。CAin。CAaFTDC

CombustionmodellingsolutionsforalternativefuelsValidationresultsofIAV´spremixedH2combustionmodel

PredictionofCombustionCharacteristics

Measured

Measured

0

.3

λ±5%

in-

Measured

5

g/kWh

BSF

C±5

%in

g/kW

h

Measured

a

20br

Measured

Measured

3

。CA

M

FB50

±3。

CAin

。CA

aFTD

C

Measured

6

4

2

0

B

Measured

Crank

Anglea

tAuto-I

gnition

±1。CAi

n。CA

0246810121416

Simulation:ReactionKineticMechanism

IAV’scustomcombustionmodelcanaccuratelypredictallrelevanthydrogencombustioncharacteristicsaswellasauto-ignitionintheunburntmass

11IAV04/2024TD-F3mrßStatus:draft,public

Combustionmodellingsolutionsforalternativefuels

λ:2.0

ValidationresultsofIAV´spremixedH2combustionmodel

1316rpm/20barIMEP

Ext.EGR:0%

PFI-perfectlyhomogeneousmixture

RobustH2combustionwithgoodrunningstabilityachievedatlambda2.0;knocklimitfoundat3。CA

12IAV04/2024TD-F3mrßStatus:draft,public

KnockPropensityIntegral/1=te

•Validationofpredictedcombustionphasing(MFB50)attheknocklimitwithaconstantcalibrationparameter

value

•Asatisfactoryresultisachievedwithamax.MFB50-deviationof2°CA(OP6)

CombustionmodellingsolutionsforalternativefuelsValidationresultsofIAV´spremixedH2combustionmodel-autoignition

MFB50SensitivityAnalysisonKnockPropensity@1316rpm/20barIMEP

MFB50~2°CA

ValidationofpredictedMFB50-points

•Generaleffectofcombustionphasingonknockpropensityisaccuratelyrepresentedbythephenomenologicalmodel

•Theknocksimulationmodelreliesonthecombustion

characteristicspredictedbyIAV’shydrogencombustionmodel

13IAV04/2024TD-F3mrßStatus:draft,public

CombustionmodellingsolutionsforalternativefuelsChallengeswithH2duetoinhomogeneities

•SufficientmixturepreparationisthemostcrucialissuewithH2-ICE

•BeneficialdiffusionbehaviourofH2comparedtootherfuelsplayaratherminorroleduetotherelevanttimescales.

•Insufficienthomogeneitydeliverspoorcombustion-andemissionsperformance.

•H2featuresfastcombustionevenindiluted/leanconditions

•Whilethisfastcombustionisbeneficialforefficiencyandcombustionstability,itcreateshightemperature

•Minimumgloballambdainthemapshallbearound~2withonlysmalllocaldeviations(s(λ)<0.1)inordertoavoidNOxcreation

•FasterH2combustionleadstoincreasedpcylandTcylcomparedtogasoline

•Ultimately,highpandTleadtodrasticallyreducedignitiondelayauto-ignition

•Dilution(air/EGR)mitigatesthisissueandenableoperationathigherspecpower

•Poorhomogeneityandrichspotsneedtobeavoided(PI,Knock,Backfire)

14IAV04/2024TD-F3mrßStatus:draft,public

CFDResultLambda

•Injection

•Flow

•Geometry

•Timing

•IAVphenomenologicalcombustionmodel:

•Gasexchange,charging

•Strategy/optimization

lean

rich

-3D

IAV1DLink

Input:CFDresultor“worst

case”assumption

CombustionmodellingsolutionsforalternativefuelsConsiderationofinhomogeneitiesforauto-ignitionprediction

Maindriverforknockandpre-ignitionphenomenaarelocalinhomogeneitiesconcerningtemperatureandlambdadistribution

1DSimulation

hot

likerichzonesandinfluenceof

IAV1Dauto-ignitionmodeliscapabletotakelocalinhomogeneities

plug,

spots(spark

exhaustvalve)intoaccount:

Combustioncalculationwitha“global”enginelambda(two-zonecalculationwiththeentrainmentmodel)

Auto-ignitioncalculationwithLivengood-Wuintegralrepresentingthedegreeofchemicalreactions(pre-

reactions)intheunburnedzone:

Auto-Ignitionpredictionbasedonalocalrichlambdazone

Auto-Ignitionpredictionconsideringalocaltemperatureofahotspot

IAVphenomenological1Dcombustionmodeliscapabletoconsidertolocalinhomogeneitiesoflambdaand

temperatureforauto-ignitionandknockprediction

15IAV04/2024TD-F3mrßStatus:draft,public

CombustionmodellingsolutionsforalternativefuelsConsiderationofinhomogeneitiesforauto-ignition

•IAV’sproprietaryhydrogencombustionmodel

packageenablesthepredictive0D/1Dsimulationofhydrogencombustion,knockpropensityand

NOxemissions

•H2-modelscanbeusedforbothsteady-stateandtransientsimulations

•DedicatedGUIformodelparametrizationthatcanbeembeddedintoanyenginemodel

•FullyintegratedresultoutputinGT-POST

•H2-modelscompatiblewithallGT-POWER

versionsafterV2016andavailablefordifferentoperatingsystems

16IAV04/2024TD-F3mrßStatus:draft,public

Auto-ignat0%MFB(-3°CA)

Pre-ignition

Auto-ignat0%MFB(0°CA)

Auto-ignat10%MFB(5°CA)

Auto-ignat35%MFB

Auto-ignat65%MFB

Auto-ignition

Noauto-ignition

limit

Combustionmodellingsolutionsforalternativefuels

SensitivityonAuto-IgnitionTendency:Tunburned

•Localhotspotsmightbemodeledviatheinfluenceonlocalunburnedtemperature

−Hotspots(e.g.exhaustvalve,sparkplug)arecharacterizedbyanincreasedlocalunburnedmixturetemperature

−Calibrationofmixtureinhomogeneitiesandhotspotsbasedon3DCFDsimulationresults,combiningthehighfidelityof3DCFDsimulationswiththeexcellentbalancebetweeneffortandaccuracytypicalfor0D/1Dapproaches

•Exemplaryvariationoflocaltemperatureatahotspotrepresentingtheauto-

ignitionlocationintheunburntzone

•Hotspotsrepresentedbymarginally

highertemperatures(+2..4%)resultinanincreasedknockpropensity

•Anunburnttemperatureincreaseofjust6%alreadyresultsinamega-knock

(massfractionburnedatauto-ignitionbelow1%)

17IAV04/2024TD-F3mrßStatus:draft,public

•ExemplaryvariationoflocalLambdaattheauto-ignitionlocationintheunburntzone

•Increasedauto-ignitionpropensityatlocalrichzones:

−Richerlambdaresultsinanearlierauto-

ignition;retardingtheignitiontimingrequiredtoreduceknocktendency

Combustionmodellingsolutionsforalternativefuels

SensitivityonAuto-IgnitionTendency:λunburned

•IAV’sauto-ignitionmodeliscapableofconsideringtheeffectsoflocalrichzonesand/orhotspots

−Combustioncalculationbasedonacylinder-averagedin-cylinderLambdavalue,asinhomogeneityeffectonburnratenegligibleinmostcases

−Auto-Ignitionpredictionconsideringlocalrichzonesandgastemperatures(e.g.hotspots)basedon3DCFD

coldflowsimulationresults

Auto-ignat68%MFB(22°CA)

Auto-ignat79%MFB(26°CA)

Auto-ignat96%MFB(34°CA)

NoknockingMFB50=

18.6°CAaFTDC

Knocklimit

18IAV04/2024TD-F3mrßStatus:draft,public

ApplicationExamplesforIAV´shydrogencombustionmodel

(LP-)DIpostinjectionH2

Boosting/Optimization1DsimulationforH2engines

CombustionmodellingsolutionsforalternativefuelsApplicationExample:H2LPDIwithpost-injection

•IncontrasttoPFIhydrogeninjection,a2nd(LP-)directinjectionoffersanadditionalchancetoincreaseboostwhichinturncanbeusedtoimproveeitherpowerperformanceorreduceNOxemissions

•Theeffectofa2ndlateinjectiononexhaustenthalpyhasbeeninvestigatedbyIAVbothexperimentallyandin1Dsimulation

•Duetotheimpactonengineefficiency,this”solution“mightbeappliedspecificallyintransientoperationonly

Stationaryat1200rpm/14barTransientloadresponseat1200rpm

20IAV04/2024TD-F3mrßStatus:draft,public

Combustionmodellingsolutionsforalternativefuels

LPDIwithpost-injection:cylinderpressureanalysis

Stationaryat1200rpm/14bar

w/postINJ(pred.model)w/postINJ(exp.)

•Verygoodagreementbetweenpredictive1DmodelandmeasurementforwardsimulationcapabilityalsoforpostinjectionandimpactonEATsimulation!

21IAV04/2024TD-F3mrßStatus:draft,public

ApplicationExamplesforIAV´shydrogencombustionmodel

(LP-)DIpostinjectionH2

Boosting/Optimization1DsimulationforH2engines

engine

Combustionmodellingsolutionsforalternativefuels

TC-matchingformediumdutyLPDIengine

•(LP-DI)engineshaveaverymuchdifferentdemandontheboostingsystemthanPFIengines

•IAV´spredictiveH21Dcombustionmodelallowsanefficientandaccurateoptimizationoftheboostingsystem

HP-stage

LP-stage

23IAV04/2024TD-F3mrßStatus:draft,public

MassMultiplierLP-stage

engine

1.35

torque[Nm]

1.30

1.25

1.20

HP-stage

1.15

LP-stage

)

2.

(λ

1.10

1.05

1.00

TC)

(D

Bas

0.95

0.90

0.85

Combustionmodellingsolutionsforalternativefuels

TC-matchingformediumdutyLPDIengine

76

5

De

signa

rea

979

1000

=

rpm05

esize

iesel-

0.850.900.951.001.051.101.151.201.251.301.35

MassMultiplierHP-stage

24IAV04/2024TD-F3mrßStatus:draft,public

36.0

MassMultiplierLP-stage

engine

1.35

1.25

765

1.20

HP-stage

0.90

Combustionmodellingsolutionsforalterna