Benefits of Direct Injection in Hydrogen Engines · Benefits of Direct Injection in Hydrogen...
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1 Benefits of Direct Injection in Hydrogen Engines ERC Research Symposium Madison, WI June 6, 2007 Brad Boyer - H2ICE Research Ford Motor Company °
Transcript of Benefits of Direct Injection in Hydrogen Engines · Benefits of Direct Injection in Hydrogen...
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Benefits of Direct Injection in Hydrogen Engines
ERC Research SymposiumMadison, WI
June 6, 2007
Brad Boyer - H2ICE Research Ford Motor Company°
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Agenda
� General targets, emission approaches� Hydrogen properties� Limitations with Port Fuel injection� Rationale for Direct-Injection
� Inherent benefits
� DI Combustion Development� Efficiency and emissions of alternative combustion modes
� Comparison to gasoline� E450 H2ICE Shuttle� Conclusions
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H2ICE Research Targets
H2ICE Research
Emissions
Target: SULEV or Better
Performance
Target: Equal to Naturally Aspirated Gasoline
Implementation
Target: Transparent to Customer
Efficiency
Target: 25-35% over gas (Comparable to Diesel)
Competitive with Fuel Cell (when hybridized)
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Emissions with H2ICE
� NOx Emissions� NOx emissions are the only regulated emission of
significance with H2ICE
� Opportunities for reducing NOx
» Lean Operation (Φ≤0.4)
» Lean aftertreatment (LNT, LNC, SCR)
� Multi-injection with DI
� Water injection
» TWC - PFI throttling/high EGR or DI required
� CO2 and Carbon Based Emissions� Produced entirely from combustion of engine oil
� Reduced 99+% compared to gasoline
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Agenda
� General targets, emission approaches
� Hydrogen properties
� Limitations with Port Fuel injection
� Rationale for Direct-Injection, inherent benefits
� DI Combustion Development� Efficiency and emissions of alternative combustion modes
� Comparison to gasoline
� E450 H2ICE Shuttle
� Conclusions
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Hydrogen Properties
Source: NHA 2006 paper
•Stoichiometric Power Density vs. Gasoline
DI H2 / Gasoline = 120 / 43.5 * 14.7/34.4 = 117%
•Combustion phasing (flame velocity scales with phi)
•Knock, high autoignition temperature (~130 octane)
•No soot / wall wetting constraints
•Thermal Losses ( < 1/4 quench distance of gasoline/air)
• Pre-ignition concerns
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Agenda
� General targets, emission approaches
� Hydrogen properties
� Limitations with Port Fuel injection
� Rationale for Direct-Injection, inherent benefits
� DI Combustion Development� Efficiency and emissions of alternative combustion modes
� Comparison to gasoline
� E450 H2ICE Shuttle
� Conclusions
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0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-20-10010203040506070
Spark (CA BTDC)
ΦΦ ΦΦ
CR=12.2 2.3L NA 3000 RPM KnockPreignitionBackfireKnock
Preignition
BLD
MBT
BackfireMisfire
Power Density Limitations with Port Fuel Injection (PFI)
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4000 rpm / 0.6 phi / PFI
-20
0
20
40
60
80
100
120
140
-200 0 200 400 600 800 1000
Cyl1PresTrace vs deg
bar
deg (Engine Cycle = 227-228)
Backfire
Misfire
Knock
Preignition
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Single Cylinder H2ICE, 16:1 CR, 4000 RPM, Phi = 0.61, PFI
0 .1
1
1 0
1 0 0
1 0 .0 0 1 0 0 .0 0 1 0 0 0 .0 0
1 s t2 n d3 rd�����������
���� �
�� ������
�� �������
�� ����������������� ����
Max Equivalence RatioNA unless noted
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
Speed (RPM)
Ph
i_m
ax
12.5 Zetec 14.7 Zetec 12.2 2.3L
12.2 2.3L SC 12.0 Single 16.0 Single
PFI is phi-limited at medium to high engine speeds
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H2 Combustion Challenges
� 3 types of Abnormal Combustion� Pre-ignition is undesirable combustion during the compression stroke initiated
prior to spark.
� Backfire/Flashback is undesirable combustion that occurs before the intake valve closes and can be seen in the intake manifold (with PFI).
� Knock is spontaneous ignition of a portion of the end gas occurring after spark.
� Hydrogen has a low ignition energy and wide limits of flammability. This makes hydrogen engines particularly prone to pre-ignition.
� Pre-ignition sources� Hot spots (spark electrodes, valves, engine deposits
� Bulk gas igniting rich spot
� Ignition system interactions (static, dwell initiation etc.)
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Why Hydrogen DI?Inherent Benefits
� Power density improvement� Air is not displaced by H2 during intake stroke
� Elimination of backfire� H2 injection after intake valve closing
� Recovery of a portion of tank energy � Ideally inject at TDC
� Tank 350 or 700 bar, rail 20-250 bar typically
� Reduced pre-ignition tendency � Late injection results in less compression heating, in-
cylinder residence time and exposure to hot spots
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Volumetric Efficiency Comparison
125+%102%~115% (Source: HyICE)
70%Base
H2PFI Positive
Displacement Supercharger
H2DI
H2Cryogenic PFI
H2PFI
GasolinePFI
Fuel
Vol
. Eff
y.
Graphic source: HyICE
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������� ���
���
� ���� ��������
� ���� ��������
DI Volumetric Benefit Confirmed
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0ΦΦΦΦ _mass
������
�� ��
� ��� �������� � ��� ��������
Up to 30% benefit
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Dynamometer DevelopmentAgenda
• Single cylinder test engine
• Typical Phi/EOI Sweep
• Various Combustion/Injection Modes
• PFI
• Single (early) DI
• Multi-Injection DI
• Stratified DI
• Interesting PV Plots
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DI Single Dynamometer Installation
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Research Engine Specifications
WetCylinder liner
Dry sumpLubrication
9.5 mm / 9.5 mmMax. valve lift
DOHC, direct acting mechanical bucket, toothed belt, 230 deg duration eventValvetrain
35mm intake30mm exhaustValve Sizes
2 intake, 2 exhaustNumber of valves
120 barMax. cylinder pressure
7000 RPMMax. speed
10-16 variableCompression ratio
0.5 L Displacement
Ford dedicated designType
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Typical Early DI Phi Sweep
0.0
1000.0
2000.0
3000.0
4000.0
5000.0
6000.0
0.1 0.3 0.5 0.7 0.9 1.1
FGN
OX
(ppm
)
70.0
80.0
90.0
100.0
110.0
120.0
130.0
0.1 0.3 0.5 0.7 0.9 1.1
ISFC
(gm
/kW
h)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0.1 0.3 0.5 0.7 0.9 1.1
Phi.ratio
CO
V IM
EP
(%)
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
0.1 0.3 0.5 0.7 0.9 1.1
Phi.ratio
EO
I (de
g B
TDC
)
20
EOI Sweep – 1500 rpm / Cont. PW
1640.0
2640.0
3640.0
4640.0
5640.0
6640.0
7640.0
8640.0
40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0
FGN
OX
(ppm
)
70.0
72.0
74.0
76.0
78.0
80.0
82.0
84.0
86.0
88.0
90.0
40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0
ISFC
680.0
700.0
720.0
740.0
760.0
780.0
800.0
820.0
40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0
EOI (BTDC)
IME
P (k
Pa)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0
EOI (BTDC)
Phi
Early Injection
Start of OVI
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Cylinder Pressure – 2000 RPM Single Inj DI
0
10
20
30
40
50
60
70
80
90
-80 -30 20 70 120 170
Crank Angle (degree)
Cyl
inde
r P
ress
ure
(bar
)
Phi = 0.17
Phi = 0.3
Phi = 0.4
Phi = 0.5
Phi = 0.6
Phi = 0.7
Phi = 0.8
Phi = 0.9
Phi = 1
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1500 rpm / Const. PW
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9
Log V (cc)
Log
P (b
ar)
40 EOI130 EOI180 EOI
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Single DI – Medium Load
Single DI
Injection
TDCIVCBDC
Late Injection for maximum pressure recovery (stability limited)
No displacement of air with H2
Poor mixing time High NOx � 0.5-0.6
Late Injection for reduced residence time and pre-ignition risk
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Typical PFI vs. Early DI Phi Sweep
- 10.0
990.0
1990.0
2990.0
3990.0
4990.0
5990.0
6990.0
7990.0
8990.0
0.1 0.3 0.5 0.7 0.9 1.1
FGN
OX
(ppm
)
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
220.0
240.0
0.1 0.3 0.5 0.7 0.9 1.1
ISFC
- 10.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.1 0.3 0.5 0.7 0.9 1.1
Phi.ratio
SP
AR
K (d
eg)
PFI
DI
10.0
30.0
50.0
70.0
90.0
110.0
130.0
150.0
170.0
0.1 0.3 0.5 0.7 0.9 1.1
Phi.ratio
mE
OIS
etD
_1 (d
eg)
25
1500 rpm / 0.6 Phi
-0.5
0.0
0.5
1.0
1.5
2.0
1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9
Log V (cc)
Log
P (b
ar)
PFISingle Inj. DI
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Multi-DI - Medium LoadTDCIVC
Multi DI Inj 1Inj2
BDC
Late Injection for maximum pressure recovery (stability limited) 0.4 Phi
No displacement of air with H2
Low NOx all �
Secondary 0.2 Phi Locally RichInjection into flame
Secondary Inj at ideal location for pressure recovery
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Single Injection vs. Multi-injection1500 rpm
0
1000
2000
3000
4000
5000
6000
7000
8000
0.5 0.6 0.7 0.8 0.9 1Phi.Ratio
FGN
Ox
(ppm
)
Multi-injectionSingle Injection
Significant Reduction in FGNOx
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Single Injection vs. Multi-injection1500 rpm
70
75
80
85
90
95
0.5 0.6 0.7 0.8 0.9 1Phi.Ratio
ISFC
(gm
/kW
h)
Multi-injectionSingle Injection
Some to no ISFC penalty
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1500 rpm / 0.6 Phi
-0.5
0.0
0.5
1.0
1.5
2.0
1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9
Log V (cc)
Log
P (b
ar)
PFISingle Inj. DIMulti-Inj. DI
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Stratified DI – Medium LoadTDCIVC
Stratified DI
Injection
BDC
Near Ideal late Injection timing for maximum pressure recovery (stability limited) 0.4 Phi
No displacement of air with H2
Late Injection for reduced residence time and pre-ignition risk
Minimal Additional Compression Work
Poor mixing time
High NOx below 0.6 �
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Early vs. Stratified Injection
60.0
70.0
80.0
90.0
100.0
110.0
120.0
130.0
0.1 0.3 0.5 0.7 0.9 1.1
ISFC
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0.1 0.3 0.5 0.7 0.9 1.1
IME
P01
_CO
V (%
)
- 10.0
10.0
30.0
50.0
70.0
90.0
110.0
130.0
150.0
170.0
0.1 0.3 0.5 0.7 0.9 1.1
Phi.ratio
EO
IT (B
TDC
)
Early Injection
Stratified Injection
- 10.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.1 0.3 0.5 0.7 0.9 1.1
Phi.ratio
SP
AR
K (d
eg)
32
Early vs. Stratified Injection
Higher FGNOx concentration at lower Phi
-10
490
990
1490
1990
2490
2990
3490
3990
4490
0.1 0.3 0.5 0.7 0.9 1.1
Phi
FGN
OX
(ppm
)
Early In jectionS tratified In jection
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1500 rpm / 0.4 PhiSingle DI vs. Stratified DI
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
1.0 1.5 2.0 2.5 3.0
Log V (cc)
Log
P (b
ar)
Single DIStratified DI
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Hydrogen Combustion Modes
Single DI
TDCIVC
Multi DI
Stratified DIInj - Low
PFI Inj - Low
BDC
Inj – Hi Load
Inj – Hi Load
Inj - Low
Inj 1 - Low Inj 2 - Low
Inj 2 - HiInj 1 – Hi Load
Inj – Hi LoadHi Load (�>0.7) same as Single DI
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ISFC and NOx of Various Strategies
60
65
70
75
80
85
90
95
100
105
110
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
Equivalence Ratio
ISFC
(gm
/kW
hr)
PFIEarly DIStratified DIMulti-injection
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
Equivalence Ratio
FGN
OX
(ppm
)
PFIEarly DIStratified DIMulti-Injection
36
Partial Efficiency Map
FORD CONFIDENTIAL
High pumping losses
Heat losses (high phi)
Heat transfer, residence time
Too lean, poor stability
37
3000 rpm / 0.6 Phi / 8.5 bar NMEP / 400 ppm
-0.5
0.0
0.5
1.0
1.5
2.0
1.5 2.0 2.5 3.0Log V (cc)
Log
P (b
ar)
Multi-injection, Spk = 16°
Single-injection, Spk = 6° Injection #1 70% @ 90° EOI
Injection #2 30% @ TDC BOI
Injection 65° EOI
Single Injection with Spark Retard vs. Multi Injection @ MBT Equal NOx and Efficiency
38
1500 rpm / 861 A/F 300 cycle avg / No Misfire
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
1.0 1.5 2.0 2.5 3.0
Log V (cc)
Log
P (b
ar)
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Agenda
� General targets, emission approaches
� Hydrogen properties
� Limitations with Port Fuel injection
� Rationale for Direct-Injection, inherent benefits
� DI Combustion Development� Efficiency and emissions of alternative combustion modes
� Comparison to gasoline
� E450 H2ICE Shuttle
� Conclusions
40
Thermal Eff. of Gasoline and H2 DI1500 rpm
0.2
0.25
0.3
0.35
0.4
0.45
0 200 400 600 800 1000 1200 1400
NMEP
Ther
mal
Eff
icie
ncy
ITE GasolineITE H2 HB DINTE GasolineNTE H2 DI
Pumping lossPumping loss
H2DI
98 RON Gas
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Power Density Comparison
0
2
4
6
8
10
12
14
1000 2000 3000 4000 5000 6000
Engine Speed (rpm)
BM
EP
(bar
)
H2 PFIH2 DIGasoline
42
H2 DI vs. Gasoline PFI1500 rpm / WOT
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
1.0 1.5 2.0 2.5 3.0
Log V (cc)
Log
P (b
ar)
H2 DIGasoline PFI
Knock limited
Fast / efficient combustion
(over 9 bar/deg max rise rate, NVH concern)
43
0
2000
4000
6000
8000
10000
0 2 4 6 8 10 12 14 16 18 20BMEP (bar)
Engine Load
NO
x (p
pm)
NOx Emissions ComparisonGasoline, H2, Boost, DI
Port H2 Injection Naturally Aspirated
Port H2 Injection/ Supercharged & Intercooled
Direct H2 Injection /N.A. – Multi-Injection
PFI Gasoline
Projected Direct H2 Boosted – Multi-Injection
Benefit w/boost
Benefit w/ DI
44
4
6
8
10
12
14
16
1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
Speed (RPM)
Eng
ine
Load
, B
ME
P (b
ar)
Torque ComparisonGasoline, H2, Boost, DI
Port H2 Injection Naturally Aspirated (NA)
Port H2 Injection/ Supercharged & Intercooled
Direct H2 Injection, NA
PFI Gasoline, NA
45
Hi-Level Injection and Boost System Comparison
High boost requirements
Lean PFI w/ boosting
DI injector durability
80+ bar rail pressure
(multi-inj)
DI w/ boosting
20-100 bar rail pressure
Rail pressure requirement
Backfire / Pre-ignition Risk
DI injector durability
DI - NA
Aftertreatment at phi >0.5, Boost requirements
PFI w/ boosting
Vol EfficiencyThrottling or VCT
PFI - NA
Major challengeLean NOx Strategy (phi < 0.4)
TWC Capable (phi = 1.0)
Power Density
Incr
easi
ng S
yste
m E
ffic
ienc
y
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Injector comparisons
� Evaluation of injector
geometry on mixing
and engine efficiency
60
65
70
75
80
85
90
300 500 700 900 1100 1300IMEP (kPa)
ISFC
(gm
/kW
hr)
9H7H13H
120 deg120 deg60 deg
100 deg
60 deg
100 deg 60 deg60 deg
0
20
40
60
80
100
120
140
160
0.1 0.3 0.5 0.7 0.9 1.1Phi
EO
I (°B
TDC
)
9H7H13H
47
Comparisons of Spray shapes in a Vessel (Pinjection = 100 bar)
3.2 bar
1.0 bar
134° 134°
27.5
9
65.3
8
t = 1.02 ms t = 1.00 ms
� University of Wisconsin – ERC
� Multi-jet modeling
� ERC developed multi-jet gas injection physics models with bench experimental validation
� Experimental spray chamber and Schlieren visualization technique
48
Ideal Mixture Distrubution
Well mixed core at phi = 0.4
•Well mixed core at phi 0.3-0.5
•Late cycle injection near TDC
•Heat losses to wall and piston minimized with air boundary layer
49
Development Summary� Promising results with H2ICE DI Development
� Power Density (low to mid BMEP exceeds gasoline, top comparable)
� NOx emission trends (multi-injection offers significant benefits)
� Thermal Efficiency meets or exceeds PFI everywhere
� Confirmation of inherent DI benefits� Volumetric efficiency improvement vs. H2-PFI
� Backfire elimination
� Tank energy recovery
� Challenges include� Excessive rate of pressure rise at high load (potential pilot injection solution)
� High exhaust temperatures at full load, high speed (>900 C at 5000 RPM),
� Optimization of injection event
» Spray, mixing, & combustion phasing are critical to H2-DI
50
Hydrogen DI Benefits vs. PFI
� Power density improvement� Air is not displaced by H2
during intake stroke
� Elimination of backfire� H2 injection after intake valve
closing
� Recovery of a portion of tank energy � Ideally inject at TDC
� Tank 350 or 700 bar, rail 20-250 bar typically
� Reduced pre-ignition tendency � Late injection results in less
compression heating, in-cylinder residence time and exposure to hot spots
Inherent� Reduced thermal losses with
charge stratification � minimal wall contact with fuel
� Low NOx, multi-injection strategies
� Pressure rise rate control with multi-injection
� Improved thermal efficiency� Increased CR potential
Injection Process
51
E-450 H2ICE Shuttle Bus Fleet� E-450 chassis with aftermarket Shuttle Bus body
� 6.8L Supercharged Hydrogen Internal Combustion Engine (H2 ICE), Port Fuel Injected
� 350 Bar/5000 PSI Hydrogen Fuel Storage System
� Hydrogen Management System
� Compliant (not certified) to Canadian and Federal standards
� Vehicle Range: 150 - 200 miles
� Emissions: 2010 Phase II Compliant
� Engine Performance:
» 310 ft-lb @3000 rpm
» 235 hp @4000 RPM
� Performance & Reliability equivalent to 2004 Ford CNG Shuttle Bus
� Vehicle Variable Cost (Pilot Volumes): $250K
� Customer 2-3 year leases begin: 4Q2006
52
�!"#�$�%&�'������(��)�)��*����� Supercharger/Intercooler-3300cc Twin Screw-Water-to-air intercooler
Piston/Rod/Rings-Forged Eutectic piston-Forged steel rods
FEAD-Supercharger-2nd alternator
Damper-Tuned for H2 combustion
Fuel Injectors-Designed for H2
Fuel Rail Assemblies-Greater Volume
Spark Plug-Iridium tipped
Ignition Coil-High energy-Reduced feed forward spark
PCV System-External oil separator
Valves/Seats-Premium material
New oil formulation-Low ash content- Extra corrosion inhibitors
Head Gasket-Rated for 100 bar
Intake Manifold-Purpose Designed
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Acknowledgements
� National Laboratory CollaborationArgonne: Steve Ciatti, Henry Ng, Thomas Wallner
Lawrence Livermore: Salvador Aceves, Dan Flowers
Sandia: Chris White, Joseph Oefelein, Dennis Siebers
Oak Ridge: Johney Green, Todd Toops
� University InteractionsUniversity of Wisconsin – ERC
