gasoline engine technology for high efficiency

Gasoline Engine Gasoline Engine ggTechnology for High Technology for High

EfficiencyEfficiency

Dr. Terry AlgerSouthwest Research Institute

Dr. Terry AlgerSouthwest Research Institute

©Copyright Southwest Research Institute ® 2014

Southwest Research Institute® San Antonio, Texas©Copyright Southwest Research Institute ® 2014

Losses and Opportunities for Improvement in Gasoline EnginesImprovement in Gasoline Engines• Current trend of

downsizing and Coolant downsizing and boosting offers significant challenges for high efficiency Brake

Heat Losses

for high efficiency powertrains– Low CR– Large enrichment region

PowerExhaust Heat Losses– Large enrichment region

– Significant thermal losses

• Particularly challenged

Losses

Cycle Particularly challenged in “real world” driving conditions and on highly loaded cycles

LossesFriction Losses


highly loaded cyclesCombustion

Losses Pumping Work

Cooled EGR Impact on Engine PerformancePerformance

Reduced Knock Improved Emissions• High CR operation enabled• Improved combustion phasing

• Reduced PM / PN • Reduced NOx and CO

Significantly Higher Efficiency and

Lower Emissions

Improved Cycle Efficiency• Reduced Heat Transfer

d l

Lower Exhaust Temperatures• Eliminates enrichment requirementE bl VGT


• Improved Cycle • Enables VGT

Knock Suppression with EGR87 octane to 92 octane has same knock suppression as increasing EGR from pp g

15% to 25% with GDI.

10% EGR ~ 5 point AKI increase

30

35 87 ON 93 ON 100 ON

20

25

MFB

[o aTD

C]

EGR = 12%ON = 6

15

20

EGR = 15%ON = 7

CA

50%


0 5 10 15 20 2510

ON = 7

EGR [%]

Improved Cycle Efficiencies Through Knock ReductionKnock Reduction

Modern GDI engine/1500 rpm / 60% load

HEDGE concepts applied:Cooled EGRAdv. Ignition (DCO)g ( )2‐Stage Boosting

Low P EGR system


Emissions Reduction With EGR

/


Data from modern GDI application @ 3000 rpm / 75% load

Enabling Technologies for High Dilution ApplicationsDilution Applications


Full Map Fuel Economy Improvement with Cooled EGRwith Cooled EGR

22BSFC [g/kWh]

1.6 L GDI Engine25 % EGR

1.6 L GDI Engine (series configuration) Full map improvement =

real world and test cycle

240

260260

14

16

18

20

P [b

ar]

BSFC [g/kWh]

225

20

22BSFC [g/kW-hr]

10.5 : 1 CR real world and test cycle FE improvement

260

230

6

8

10

12

Eng

ine

BMEP

230

225

22014

16

18

P [b

ar]

330300

1500 2000 2500 3000 3500 40002

4

Engine Speed [rpm]

8

10

12

Engi

ne B

MEP

•Typical improvement over GDI

330300

260

2

4

6baseline : 6-9%•Improvement over TC MPI engine (including adding cam phasers) : 8 11%


1500 2000 2500 3000 3500 40002

Engine Speed [rpm]

phasers) : 8-11%•Improvement over NA MPI baseline : > 11%

Future Work on LPL EGR Engines• SwRI’s HEDGE III consortium

continues to look at advancements in LPL EGRadvancements in LPL EGR technologies– Synergies with highly variable

valvetrainsC ti i t i– Continuous improvement in subsystems Ignition Boosting Controls

– Understanding design requirements In-cylinder aerodynamics Engine architecture

– Dual-loop EGR Optimized pumping work at low and

high loads


g High power density with single TC

Synergies with LPL EGR and Variable ValvetrainsValvetrains

• Primary FE benefit from EGR l dEGR at part load comes from– Increased CR– Reduced HT

losses – Charge property

i timprovements• Pumping work

improvement limited bylimited by dilution tolerance


Blended EGR*Dual-loop EGR for Pumping Work OptimizationDual loop EGR for Pumping Work Optimization

• HPL EGRAt low load– At low load

– At high speed / high load• LPL EGR

4000 RPM4000 RPMBlended EGRBlended EGR

4000 RPM4000 RPMBlended EGRBlended EGR

6000 RPM6000 RPMHPL EGRHPL EGR6000 RPM6000 RPMHPL EGRHPL EGR LPL EGR

– At low speed / high load2000 RPM2000 RPMLPL EGRLPL EGR

2000 RPM2000 RPMLPL EGRLPL EGR

•HPL + LPL EGR− At mid-speed / high load

©Copyright Southwest Research Institute ® 2014*patent pending*patent pending*patent pending*patent pending

Challenges Remain

Knock / Reduced Reduced Flame Speeds /Knock / Reduced CR in Boosted

Engines

Reduced Flame Speeds / Increased Combustion

Inefficiencies

HighEGR High Efficiency Barriers

Tolerance / Combustion Stability

Heat Rejection

To increase efficiency even further, several areas of improvement are required for


areas of improvement are required for cooled EGR engines

Dedicated EGRImproving Efficiency Via In-Cylinder ReformingImproving Efficiency Via In Cylinder Reforming

ɸ > 1.00ɸ > 1.00

ɸ = 1.00ɸ = 1.00


Sources of Improvement in D-EGR

• Knock resistancek d• Pumping work reduction

• Improvement in • Reduced NOx emissions ‐> less reductant needed for TWC control

25% EGRreductant needed for TWC control (leaner combustion in main cylinders)

• Eliminate main cylinder enrichment

• Improved fuel octane ‐> knock resistance• Improved dilution tolerance• Use EGR at lower engine temperaturesReformate Use EGR at lower engine temperatures• Faster burn velocities / Reduced ignition energy• Improvement in

Reformate

NOTE : D-EGR is not an “exclusive” technology It can integrated into almost


NOTE : D-EGR is not an exclusive technology. It can integrated into almost any existing engine architecture (i.e. Atkinson-cycle, VTEC, etc)

Improving the FundamentalsEnabling High CR and Impacting the Working FluidEnabling High CR and Impacting the Working Fluid

Cool combustion + Cool combustion + dilution + reformate = dilution + reformate = dilution + reformate = dilution + reformate =

higher higher

1.1 < 1.1 < DD < 1.5< 1.51.1 < 1.1 < DD < 1.5< 1.5

Higher Higher Improved Improved


Higher Higher = = Improved Improved ottootto

Enabling High EGR Tolerance10

2000 rpm / 2 bar bmepTest PlatformTest Platform2006 MY 2.4 L Chrysler World Engine2006 MY 2.4 L Chrysler World Engine

6

8

%]

14:114:1 CRCR

4

6

V IM

EP [%

2C

o

1.00 1.05 1.10 1.15 1.20 1.250

Cylinder #1


Cylinder #1

Faster combustion = Improved Stability at 25% EGRFaster combustion = Improved Stability at 25% EGR

Increased Knock Resistance

190

[N-m

] 20002000 RPM WOTRPM WOT

170

180

ak T

orqu

e

160

170

imite

d Pe

a

ReformateReformate Impact on Impact on Effective RONEffective RON

++150

160

Kno

ck L


Faster Burn Rates =Faster Burn Rates =ImprovedImproved Knock ToleranceKnock Tolerance

1.00 1.05 1.10 1.15 1.20150

Dedicated Cylinder

Improved Torque at High Compression RatiosRatios

260

2.0 L TC MPI engine2000 RPM

12.6 %

3.3 % EGR

240

250

26012.5:1 CR

25.8 % EGR

25 2 % 24.3 %

20%

220

230

240

[g/kW‐hr]

25.2 %

200

210

220

BSFC

LPL 12.5:1 CR

190

200

6 7 8 9 10 11 12 13 14 15 16 17 18 19

[b ]

D‐EGR 12.5:1 CR


Enables High-Efficiency DownsizingBMEP [bar]

18

Enabling Low Octane Fuel?12

bar]

D‐Phi = 1.2

8

10

Load

at M

BT [

23 % EGR22 % EGR

6

8

d Maxim

um L

4

Knock Limite

LPL EGR 12.5:1 CR, 92 AKI

0

2

500 1000 1500 2000 2500 3000 3500 4000

LPL EGR 12.5:1 CR, 87 AKI

D‐EGR 12.5:1 CR, 88 AKI


500 1000 1500 2000 2500 3000 3500 4000Engine Speed [rpm]

19

Reduced Emissions• Combustion

efficiency returns BSHC

4.5

18

BSCO

4 0

BSNOx

0 27

Soot Mass yto nearly non-dilute levels

• Reformate 3 0

3.5

4.0

4.5

14

16

18

3.0

3.5

4.0

0 24

0.25

0.26

0.27

Simproves HC and CO emissions

• NOx emissions2.0

2.5

3.0

HC

[g/k

W-h

r]

8

10

12

SC

O [g

/kW

-hr]

1 5

2.0

2.5

NO

x [g

/kW

-hr]

0 21

0.22

0.23

0.24 oot Mass [m

g/ NOx emissions increase slightly– Still ~ ¼ of non-

dilute case0.5

1.0

1.5 BS

H

2

4

6BS

0.5

1.0

1.5

BS

N

0.19

0.20

0.21

/kW-hr]

dilute case• Significant PM

reduction enabledEngine‐out Emissions:

1.05 1.10 1.15 1.20 1.25 1.30

D-EGR Equivalence Ratio [-]

0.00 0.00.18


enabledg2.0 L TC MPI D‐EGR Engine2000 rpm 10.5 bar BMEP

Solution for the Entire Performance MapMap

BTE~ 40% in a 2.0 L BTE ~ 42% in a 2 0 L


BTE 40% in a 2.0 L TC GDI application

~ 330 g/kWh at 2000 rpm / 2 bar bmep

BTE 42% in a 2.0 L TC MPI application

< 330 g/kWh at 2000 rpm / 2 bar bmep

D-EGR in a Vehicle• > 10% improvement in MPG

– 13% improvement over the baseline on a US FTP-75– 10% improvement on the US HWFET

• SULEV / Tier III emissions potential– Current emissions ~ US LEV III

Engineering margin still required for production applications• Drivability >= baseline vehicle


Summary

• The use of EGR – cooled LPL or H2 enriched D EGR h i ifi t ffi i b fitD-EGR – has significant efficiency benefits– Reduced knock → high CR downsizing

I d h ti– Improved charge properties– Reduced emissions and exhaust temperatures

Improved combustion phasing– Improved combustion phasing• Success demonstrated via early work in LPL

EGR leads to new research directionsEGR leads to new research directions– D-EGR

EGR + VVA


– EGR + VVA– Advanced enabling technologies

Contact InformationContact InformationDr. Terry AlgerDr. Terry Alger

Contact InformationContact InformationDr. Terry AlgerDr. Terry AlgerDr. Terry AlgerDr. Terry [email protected]@swri.org

(m) 210(m) 210--248248--64336433(w) 210(w) 210 522522 55055505

Dr. Terry AlgerDr. Terry [email protected]@swri.org

(m) 210(m) 210--248248--64336433(w) 210(w) 210 522522 55055505(w) 210(w) 210--522522--55055505(w) 210(w) 210--522522--55055505

Southwest Research Institute®


gasoline engine technology for high efficiency

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