advanced combustion technology to enable high efficiency

Advanced Combustion Technology to Enable High Efficiency Clean

Combustion

August 4th, 2008

Donald StantonResearch & Technology

2

Innovation You Can Depend On

Product Attributes Influenced by Combustion Strategy

Significant fuel economy improvementCustomer drivenLegislative initiatives

Vehicle heat rejection

Substantial increase in power density*Hybrid powertrain integrationVehicle electrificationEngine downsizing

Cost

*Power Density = power/weight

3


35

40

45

50

55

60

1985 1990 1995 2000 2005 2010 2015

Historical Perspective of HD Brake Thermal Efficiency

Bra

ke T

herm

al E

ffici

ency

(%) HECC DoE Effort

Advanced Mixed Mode CombustionAir Handling (Air on Demand –

Electronically Assisted)HPCR Fuel System Technology

Sensors / Controls Development

Advanced Engine Concepts

4


EGR Loop

Fuel System Advanced LTC

Technology Roadmap for Efficiency Improvement

Controls

Variable Valve

Actuation

Variable IntakeSwirl

TurboTechnology

Electrically Driven Components

Aftertreatment

Integration of Cummins Component BusinessTechnologies in a Cost Effective Manner

Integration of Cummins Component BusinessTechnologies in a Cost Effective Manner

Hybrid/WHR

6.7L ISB6.7L ISB 15L ISB15L ISB

5


0.0 0.2 0.4 0.6 0.8 1.0 1.2BSNOx [g/hp-hr]

BSD

PM [g

/hp-

hr]

0.30

0.32

BSF

C [l

b/hp

-hr]Δ=0.01

DPF+SCR

2007 Engine+

SCR

EGR+DOC+DPF+

SCRIn-Cylinder NOx Control

EGR+DOC+DPF

87%-92%87%-92%82%-86%82%-86% >92%>92%SCR NOx Conversion Efficiency

Engine Out PM Level Assuming DPF

Δ=0.1

2007 Engine Fuel Consumption

Advanced Fuel Injection System + EGR System + Controls

EGR System + Combustion System + Air Handling

Air Handling + Sensors + Calibration

Low ΔP, High Flow Rate EGR + VVA -

Simulated

Robustness

Advanced Combustion Concepts -

Simulated

0.0

Achieving a Wide Range of Engine Out NOx Capability

6


0.00.0Engine Out BSNOEngine Out BSNO

xx

(g/hp(g/hp--hr)hr)

BM

EP (

bar)

BM

EP (

bar)

0.20.2 0.40.4 0.60.6 0.80.8 1.01.0 1.21.2

1-stage turbo+

Low ΔP, HP Loop EGR

smoke ≤

0.4 FSNsmoke ≤

0.4 FSN

SCR Catalyst Sizing

Optimization

Smoke ≤

0.4 FSNSmoke ≤

0.4 FSN

Fixed SCR Catalyst Fixed SCR Catalyst SizeSize

2-stageturbo

Advanced EGRSystem

Increased PCP

Assumed Constant Engine Displacement

Advanced Fuel Injection System and Combustion System Optimization

Advanced Fuel Injection System and Combustion System Optimization

Power DensityMixed Mode Diffusion Controlled CombustionMixed Mode Diffusion Controlled Combustion

LTC –

AdvancedCombustion

LTC –

AdvancedCombustion

7


Combustion Strategy for Fuel Economy Improvements

SPEED (rpm)

TOR

QU

E (ft

-lbs)

Early PCCI

ConventionalDiffusion Controlled

Moderate EGR RatesDiffusion Controlled

Poor EfficiencyModerate PM and NOx

High EfficiencyLow PM and NOx

SPEED (rpm)

TOR

QU

E (ft

-lbs)

Early PCCI

ConventionalDiffusion Controlled

Moderate EGR RatesDiffusion Controlled

Poor EfficiencyModerate PM and NOx

High EfficiencyLow PM and NOx

0

200

400

600

800

1000

1200

1400

400 600 800 1000 1200 1400 1600 1800 2000

TOR

QU

E (ft

-lbs)

Early PCCI

Lifted Flame DiffusionControlled

1600

SPEED (rpm)

0

200

400

600

800

1000

1200

1400

400 600 800 1000 1200 1400 1600 1800 2000

TOR

QU

E (ft

-lbs)

Early PCCI


1600

SPEED (rpm)

Early PCCI

Smokeless

Rich

Conventional Diesel

Late PCCI

8


Extending the Range of Early PCCI

TDCCrank Angle

ignition delaytoo short

Cannot inject in this range(ign. delay too short)

Late PCCIEarly PCCI

Late PCCI ignitionand burning

PCCI ignitionand burning

compressiontemperature PCCI

injectionLate PCCIinjection

Mode Advantages Disadvantages

Early PCCI

-

Good stability-

Good fuel consumption-

High peak cyl. pressure-

Limited BMEP- Noise-

Higher cooled EGR rates

Late PCCI-

Low peak cyl. pressure-

High BMEP capability (20 bar)- Low noise

-

Narrow stability range-

Higher fuel consumption-

Needs combustion sensor

0

200

400

600

800

1000

1200

1400

400 600 800 1000 1200 1400 1600 1800 2000

TOR

QU

E (ft

-lbs)

Early PCCI


1600

SPEED (rpm)

0

200

400

600

800

1000

1200

1400

400 600 800 1000 1200 1400 1600 1800 2000

TOR

QU

E (ft

-lbs)

Early PCCI


1600

SPEED (rpm)

9


Challenges for Full Engine Operation in PCCI Combustion

0

200

400

600

800

1000

1200

1400

1600

1800

2000

600 1100 1600 2100Engine Speed [r/min]

Torq

ue [F

T-LB

S]

High Load• Rate of pressure rise

• Controls (Mode switching and stability)• Mixture preparation

•EGR rates and vehicle cooling

Light Load• Combustion Noise• Efficiency (UHC and CO)• Controls (Mode switching and stability)• Mixture preparation

10


5 bar7 bar

10 bar15 bar20 bar

BMEP

Bra

ke T

her

mal

Eff

. (%

)

Sm

oke

(FS

N)

5 bar7 bar

10 bar15 bar20 bar

BMEP

Extending the Engine Operation Range of PCCI

Combined Early and Late PCCICombined Early and Late PCCI

Reduce CO & UHC whilemaintaining acceptable NVH(especially below 5 bar BMEP)

Reduce CO & UHC whilemaintaining acceptable NVH(especially below 5 bar BMEP)

11

Innovation You Can Depend On Bow

l rim

FormaldehydePLIF

SOI=-5 ATDC, O2=14.7%

20 ATDCInjector

Equivalence Ratio Contours

1% to 3% bsfc reduction

Sandia-Cummins N14

Images Courtesy of Mark Musculus -

SNL

Engine data from2–9 bar BMEP with

3 to 7 injection events

Engine data from2-10 bar BMEP with a combination of single

and dual injection

Reducing HC and CO for Early PCCIEfficiency Improvement“Ignition Dwell”

≡

Time from end of injection to start of combustion

12


5 bar7 bar

10 bar15 bar20 bar

BMEP

Bra

ke T

her

mal

Eff

. (%

)

Sm

oke

(FS

N)

5 bar7 bar

10 bar15 bar20 bar

BMEP

Extending the Engine Operation Range of PCCI

Combined Early and Late PCCICombined Early and Late PCCI

Late PCCI limits fuel economyimprovement potential and robustness

Late PCCI limits fuel economyimprovement potential and robustness

13


0

200

400

600

800

1000

1200

1400

1600

1800

2000

600 1100 1600 2100Engine Speed [r/min]

Torq

ue [F

T-LB

S]Extending PCCI Combustion

with VVA

4% Fuel Economy at 0.2 g/bhp-hr NOx

Impact of Late Intake Valve Closing

Impact of Late Intake Valve Closing




Optimization with smoke ≤

0.5 FSN0

10

20

30

40

50

60

70

80

90

LateIVC

Std IVC LateIVC

Std IVC LateIVC

Std IVC LateIVC

Std IVC LateIVC

Std IVC

A_F egr SOI INT_MNF_P EXH_MNF_P

0

10

20

30

40

50

60

70

80

90

LateIVC

Std IVC LateIVC

Std IVC LateIVC

Std IVC LateIVC

Std IVC LateIVC

Std IVC

A_F egr SOI INT_MNF_P EXH_MNF_P

1600 RPM @ 1230 ft-lb

Main SOI

TDCCrank Angle

ignition delaytoo short

Cannot inject in this range(ign. delay too short)

Late PCCIEarly PCCI

Late PCCI ignitionand burning

PCCI ignitionand burning

compressiontemperature PCCI

injectionLate PCCIinjection

VVA

14


Challenges for Lifted Flame Combustion

Creating desired intake valve closing conditionsA/F, EGR, IMT

Fuel injection system technologyInjection pressureNozzle configuration

Fuel injection plume to plume interaction

Combustion surfacesDifficult to scale to smaller bore engines

Controls development for transient operation

0

200

400

600

800

1000

1200

1400

400 600 800 1000 1200 1400 1600 1800 2000

TOR

QU

E (ft

-lbs)

Early PCCI


1600

SPEED (rpm)

0

200

400

600

800

1000

1200

1400

400 600 800 1000 1200 1400 1600 1800 2000

TOR

QU

E (ft

-lbs)

Early PCCI


1600

SPEED (rpm)

15


Conventional Diffusion Combustion

Lifted Flame Diffusion Combustion

Lift Off Length

4≤

φ

≤

6

2≤

φ

≤

3

1≤

φ

≤

2 Advanced Lifted Flame Combustion(Scales well for smaller bore engines)

Red

uce

Liqu

id F

uel P

enet

ratio

n an

d En

hanc

e Fl

uid

Entr

ainm

ent

Creating Lifted Flame Combustion

EliminateLiquid Injection

ReducedLiquid

Penetration

16


0.8

fsNOx(g/kg fuel)

fsDP

M(g

/kg

fuel

)

4.03.53.02.52.01.51.0

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Baseline RecipeBaseline Recipe

Direct Injection -

SimulationsDirect Injection -

Simulations

Fumigated + Direct Injection -

SimulationsFumigated + Direct Injection -

Simulations

Engine Data

Advanced Lifted Flame Combustion

KIVA Simulation1600 RPM at Full Load

17


Achieving High Efficiency Combustion with a Wide Portfolio of Fuels

Wide variety of fuel types

Engines designed and sold for a global market

Mixed mode combustion

Robustness of operation

Maintain fuel efficiency gains

Exploit fuel properties for performance improvements

Virtual and Real SensorExploration

18


Exploration of Fuel Properties on HECC*

Use transient engine operation as key data sets for understanding impact of fuel properties on HECC

Explore the impact of fuel type over a variety of advanced combustion modes

Characterize the fuel compounds and properties•

Challenging for heavy fuels

Explore real and virtual fuel quality sensor technology for engine integration

Development of kinetics mechanism for analysis•

CFD analysis –

primary way to generalize key combustion knowledge gained from external collaborations

*Partners: ORNL and BP

19


PCCI Engine Performance Variation with ULSD

1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.20

5

10

15

20

Freq

uenc

y

NOx (g/kg)

Frequency distribution of NOx

1.5 2 2.5 3 3.50

20

40

60

Freq

uenc

y

Smoke (FSN)

Frequency distribution of Smoke

0.25 0.255 0.26 0.265 0.270

5

10

15

20

25

Freq

uenc

y

gisfc (lb/hp-hr)

Frequency distribution of isfc

35 40 45 50 55 600

5

10

15

20

Freq

uenc

y

Cetane

Frequency distribution of Cetane

fsNOx, gisfc, smoke, etc = f(engine parameters) + f(fuel properties)

20


0.8 1 1.2 1.4 1.6 1.8 20

5

10

Freq

uenc

y

NOx (g/kg)


0.8 1 1.2 1.4 1.6 1.8 20

50

100

Freq

uenc

y

NOx (g/kg)


2 2.2 2.4 2.6 2.80

50

100

Freq

uenc

y

Smoke (FSN)


2.3 2.4 2.5 2.6 2.70

5

10

Freq

uenc

y

Smoke (FSN)


0.2 0.4 0.6 0.8 1.0 0.2 0.4 0.6 0.8 1.0

Non-PremiumNon-Premium

Non-PremiumNon-Premium

Premium FuelPremium Fuel

Premium FuelPremium Fuel

21


Experimental resultsExperimental resultsModel PredictionModel Prediction

O2

Sensor-Based Bio-

Content Estimation

O2

Sensor-Based Bio-

Content Estimation

Virtual Sensor TechnologyVirtual Sensor Technology

Biofuels Sensing

Courtesy: Professor Shaver –

Purdue University

22


SummaryMixed mode combustion can achieve a wide range of

engine out NOx (≥0.2 g/bhp-hr)Select the right technology for each application

Development and integration of component technologies are key enablers

Additional technology exploration needed to achieve greater emission robustness and fuel economy at 0.2 g/bhp-hr engine out NOx

Advanced combustion strategies are being explored to promote lifted flame combustion and extended range PCCI combustion

Virtual and real fuel sensors are enablers for robust performance while maintaining high efficiency as fuel properties variation increases

23


Variable Swirl –

Emissions Robustness

Speed (RPM)

BMEP

(ba

r)

30002500200015001000

10

9

8

7

6

5

4

3

2

> - - - - - - - - <

4.7

1.51.5 1.91.9 2.32.3 2.72.7 3.13.1 3.53.5 3.93.9 4.34.3 4.7

DCS

LDD Recommended Swirl - Solid Body RotationKIVA Recommended Swirl

22% Reduction in Particulate Matter2.5% -

3.5% Fuel Economy Improvement 22% Reduction in Particulate Matter

2.5% -

3.5% Fuel Economy Improvement

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1 2 3 4 5

DCS Swirl #

fsD

PM (g

m/k

g)

Varying A/F Ratio

DCS Swirl

KIVA Recommendation

advanced combustion technology to enable high efficiency

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