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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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Lifted Flame DiffusionControlled
1600
SPEED (rpm)
Early PCCI
Smokeless
Rich
Conventional Diesel
Late PCCI
8
Innovation You Can Depend On
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
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
Lifted Flame DiffusionControlled
1600
SPEED (rpm)
9
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
2% Fuel Economy at 0.2 g/bhp-hr NOx
3% Fuel Economy at 0.2 g/bhp-hr NOx
3% Fuel Economy at 0.2 g/bhp-hr NOx
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
Innovation You Can Depend On
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
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
Lifted Flame DiffusionControlled
1600
SPEED (rpm)
15
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
0.8 1 1.2 1.4 1.6 1.8 20
5
10
Freq
uenc
y
NOx (g/kg)
Frequency distribution of NOx
0.8 1 1.2 1.4 1.6 1.8 20
50
100
Freq
uenc
y
NOx (g/kg)
Frequency distribution of NOx
2 2.2 2.4 2.6 2.80
50
100
Freq
uenc
y
Smoke (FSN)
Frequency distribution of Smoke
2.3 2.4 2.5 2.6 2.70
5
10
Freq
uenc
y
Smoke (FSN)
Frequency distribution of Smoke
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Innovation You Can Depend On
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
Recommended