Comparison Between Fuel Cell andComparisonBetweenFuelCellandHydrogenEngineFuelConsumption

April2008SAE2008010635

AymericRousseau,SylvainPagerit,ThomasWallner,HenningLohseBusch

Sponsored by Lee Slezak (U.S. DOE)

Thispresentationdoesnotcontainanyproprietary,confidential,orotherwiserestrictedinformation

Outline

PSATModelingAssumptions Vehicle

FuelCellSystem

H d E i HydrogenEngine

ComponentSizing

Si l ti R lt SimulationResults

Vehicle AssumptionsMidsizecarplatform Bothnonhybridandhybridconfigurationsconsidered All vehicles achieve similar performances (060mph, grade)Allvehiclesachievesimilarperformances(0 60mph,grade) AllvehicleshavesameamountofonboardH2(5kg) Componentuncertaintiestakenintoaccount UDDSandHWFETdrivecyclesconsidered

Parameter Unit Midsize Car

Ratiosbasedonfueleconomygasolineequivalentusing2008EPAcorrections

Parameter Unit Midsize CarGlider Mass kg 990Frontal Area m2 2.1D C ffi i t 0 29

Parameter Unit Value060mph s 9 +/- 0.1030mph s 3Drag Coefficient 0.29

Wheel Radius m 0.317Rolling Resistance 0.008

0 30mph s 3

Grade at 60 mph % 6

Maximum Speed mph > 100 (1)

(1) Two gear transmission used for series(1)Twogeartransmissionusedforseries

Fuel Cell System AssumptionsParameter Unit Current Status FreedomCAR

GoalSpecific Power W/kg 500 650

0.7

Specific Power W/kg 500 650

Peak Efficiency % 55 60

d l

0.5

0.6

(%)

FreedomCAR2007 Status

ModelLimitation:Theefficiencycurvesusedaresteadystate,underestimating the

0.3

0.4

Sys

tem

Effi

cien

cy ( underestimatingthe

parasiticload,whichismuchhigherinrealworlddrivingbecause of transient and non

WithoutCEM

0 10 20 30 0 00

0.1

0.2S

becauseoftransientandnonoptimumcontrolWithCompressorExpander

Module(CEM)

0 10 20 30 40 500

Fuel Cell Power (kW)

Hydrogen Engine Characteristics for C t T h l G t d f Current Technology Generated from Experimental Data Manufacturer FordMotorCo.

M d l 2 3L D t Model 2.3LDuratec

Cylinders 4

Bore 87.5mm

Stroke 94mm

Compressionratio 12

Valve train 4V DOHCValvetrain 4VDOHC

Speedrange 6000RPM

ModificationsSupercharger and intercooler Superchargerandintercooler

Hydrogenportfuelinjection

AftermarketECU4cylinderhydrogenenginesetup

Port Injected Maps Generated for Different Air/Fuel RatiosAir/Fuel Ratios

Final Port Injected Map Generated To Maximize Brake Thermal EfficiencyMaximize Brake Thermal Efficiency

Brakethermalefficiencyincreaseswithincreasedi /f l iair/fuelratio

Maximumtorquedecreaseswith increased air/fuel ratiowithincreasedair/fuelratio

Duetoleanoperationpeakefficiencyisachievedatfulll dload

Direct Injection Hydrogen Engine OperationEstimated from Single Cylinder Test Datag y

DI results in increased peak torque

Increased compression ratio & turbo charging

Hydrogen Direct Injection will increase the peak torque curve

Torque

Increased compression ratio will result in an increase in engine efficiency

Turbo-charging will increase the engine efficiency compared to supercharging

l d ll Lean part load operation will result in a further part load efficiency increase compared to throttled operation

SpeedLean part load

throttled operation

Component Average Power

140

160EngineFuel CellElectric Machine

100

120

r (kW

)

MC2 / GCBattery

SpecificPower(W/kg)

80

100

onen

t Pow

er (W/kg)

40

60

Com

po

0

20

Conv Split Series ICE FC FC HEV

Vehicle Mass

1900

2000

Future vsCurrentvs.

1800

1900

s (k

g)

Futurevs.Future

Current

1700

le T

est M

ass

1500

1600

Vehi

cl

1400

1500

C S lit S i ICE FC FC HEVConv Split Series ICE FC FC HEV

2 5

Non-Hybrid Configurations Comparison

2.0

2.5 H2ICEconsumesbetween1.7and2.1timesmorethanthefuelcell

1.5

mpt

ion

Rat

io

FutureH2ICEconsumesbetween1.6h h f l ll

1.0

Fuel

Con

sum timesmorethanthecurrentfuelcell

0.5

F

0.0Conv FC

Currentvs.current >H2ICEwillconsume1.7morethanfuelcellFuturevs.future >H2ICEwillconsume2.1morethanfuelcellCurrentfuelcellvs.futureICE>H2ICEwillconsume1.57morethanfuelcell

Hybrid Configurations ComparisonH2 ICE consumes from 1 1 to 1 2 (Split) and 1 4 to 1 6

1 4

1.6

1.8 H2ICEconsumesfrom1.1to1.2(Split)and1.4to1.6timesmorethanthefuelcell

Future H2ICESeriesconsumesthesame than current fuel cell HEV

1.0

1.2

1.4

ptio

n R

atio

samethancurrent fuelcellHEV

0.6

0.8

Fuel

Con

sum

p

0.2

0.4

F

Future H2ICESplitconsumesless(0.8)thancurrent fuelcellHEV

0.0Split Series ICE FC HEV

Currentvs.current >H2ICESplitwillconsume1.24morethanfuelcellFuturevs.future >H2ICESplitwillconsume1.1morethanfuelcellCurrentfuelcellvs.futureICE>H2ICESplitwillconsume0.8less thanfuelcell

All Configurations Comparison

1 0

1.2CurrentPowersplitHEVissimilartoCurrentFuelCellOnly

0.8

1.0

Rat

io

FutureseriesHEVisclosetocurrentFuelCellHEV

0.6

onsu

mpt

ion

0.4

Fuel

Co

0.0

0.2

Conv Split Series ICE FC FC HEV

Fuel Economy Results Analysis AllHEVsconfigurationcapturesimilaramountofenergyatthe

wheelduringdeceleration(~98%onUDDS).However,theseriesfi ti h l d t l l t i hiconfigurationshavemorelossesduetolowerelectricmachine

efficienciesthanthepowersplit.

BothHEVconfigurationsusingICEhavesimilaraverageefficienciesg g g(~31%forportinjectedand~41.5%fordirectinjectiononUDDS).

Thefuelcellsystemaverageefficiencyremainshigher(~47%ford 51% f f UDDS)currentcaseand~51%forfuturecaseonUDDS).

Inaddition,theseriesconfigurationwithH2ICEispenalizedbythedriveline inefficiencies (both generator ~90% and electric machinedrivelineinefficiencies(bothgenerator 90%andelectricmachine~81%)

Conclusion

TheDIH2ICEhasbeendefinedbasedonacombinationoffourcylinderandsinglecylinderdatageneratedfordifferentA/Fratios.

H2 ICE t i h ld b h b idi d t b titi ith f l ll H2ICEpowertrainshouldbehybridizedtobecompetitivewithfuelcellsystemsvehiclefuelconsumption.

PowersplitconfigurationoffersthebestfuelconsumptionwhenusingH2ICEduetoaddedinefficienciesintheseriesconfiguration.

Ifoneconsidersthatthecurrentfuelcellsystemefficiencieswillremainconstant in the future (most research is focused on cost and durability),constantinthefuture(mostresearchisfocusedoncostanddurability),DIH2ICEcouldprovideaninterestingoption(upto20%reductioninfuelconsumption).

If one considers both future technologies within an HEV a 10 to 40% IfoneconsidersbothfuturetechnologieswithinanHEV,a10to40%increaseinfuelconsumptionisnoticedwhenusingH2ICE.