1. Clean Fuels 2007:
June 25-26, 2007:
Fuels for Future Engines
Tom Ryan, Institute Engineer
Engine, Emissions and Vehicle Research Division
Southwest Research Institute®
San Antonio, Texas
2. Presentation Outline
Current status of HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
2
3. Presentation Outline
Current status of HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
3
5. Progression Of Heavy-Duty Legislation
And Technology In EEC
16 0.4
14 NOx (g/kW.h) 0.35
Particulates (g/kW.h
PM (g/kW.h)
12 0.3
NOx (g/kW.h)
10 0.25
8 0.2
6 0.15
4 0.1
2 0.05
0 0
90 92 95 99 05 08 10
19 19 19 19 20 20 20
0, 1, 2, 3, 4, 5, 6,
ro ro ro ro ro ro ro
Eu Eu Eu Eu Eu Eu Eu
5
Commission HD Euro 6 validation report issued end 2006
Euro 6 has been proposed as 0.5 g/Kw.h NOx and 0.002 g/kW.h particulates
6. In-Cylinder Emissions Control Use In
Production Engines
To date NOx has To date particulates
been controlled by have been controlled
reducing combustion by increasing the oxidation
temperature by rate of the fuel by
these methods. these methods.
Intercooling Turbocharging
Combustion retard Higher injection
Injection rate shaping pressure
Exhaust gas recirculation Smaller nozzle holes
(EGR)
At US 2007 and Euro 4 these methods are reaching
the limit of their practical effectiveness
and other methods my be necessary. 6
7. Charge Air Cooling
1.05
The effect of intake
NOx / [ NOx @ 50 oC ]
1.00 manifold
temperature on
0.95
25% Load
NOx is predictable.
0.90
0.85 75% Load
0.80 50% Load
100% Load
0.75
-5 0 5 10 15 20 25 30 35 40 45 50 55
Intake Manifold Temperature Co
7
8. Exhaust Gas Recirculation (EGR)
1.0 >50% NOx
0.9 reduction is possible
75% Load
25% Load over transient cycle.
0.8
NOx / [ NOx baseline ]
0.7
7% Load A particulate
1800 rpm countermeasure for
0.6
EGR is required.
0.5
0.4
0.3
0.2
0.1
0.0
0 10 20 30 40 50 60
EGR [%] 8
9. Presentation Outline
Current status of EEC HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
9
10. Weighted NOX vs. Total Aromatics
Modern EGR Equipped Engine
2.7
WEIGHTED NOX [ g/(hp-hr)
2.6
2.5
2.4
2.3
10 15 20 25 30 35 40
TOTAL AROMATICS [ % ]
NOx depends on fuel composition through the impact on the
adiabatic flame temperature
Aromatics increase the adiabatic flame temperature, and thus
the NOx emissions 10
11. Alternative Renewable Fuels
Biodiesel in the US may soon be made by petroleum refiners
rather than by using the fatty acid methyl-ester approach.
Bio-mass may also be refined using Bio-mass to liquid (BTL);
Fischer-Tropsch process.
A process has been developed Sweden to make Di-Methyl Ether
(DME) from wood chips.
UOP has a process for treating vegetable oil in the refinery
11
12. Stoichiometric Adiabatic
Flame Temperature
W EIGHTED NOx [g/(hp-hr)]
2.70
2.65
2.60
2.55
2.50
2.45
2.40
2.35
2.30
12.6 12.8 13.0 13.2 13.4 13.6 13.8 14.0
FUEL HYDROGEN [%]
• NOX emissions show a strong relationship to hydrogen content.
12
13. Fuel Effects on NOx (modeling results)
10
The flame temperature 8
NOx (g/hp/h)
effects NOx. 6
4
2
Diesel H/C=1.8 0
Methane H/C = 4.0 Adiabatic Flame Temperature (K)
2950
2900
2850
2800
2750
2700
2650
2600
1.5 2 2.5 3 3.5 4 13
4.5
Hydrocarbon/Carbon Ratio
14. Relationship Between PM and
Fuel Composition
Combustion Reactor 22
20
Experiments Show Clear
18
Relationship Between Soot
Soot (mg/m3)
16
and Composition 14
12
Basic Fuel Parameter is the 10
Fuel H/C Ratio 8
6
4
1.3 1.4 1.5 1.6 1.7 1.8 1.9
Fuel H/C Ratio
14
15. Alternative Fuel Properties
Alternative Fuel Properties
2-D Diesel
Property Units Biodiesel DME FT Diesel
U.S.
Cetane Number 55 44 55 90+
Sulfur < 15 333 0 0
Nitrogen ppm 18 114 0 0
Aromatics % mass 0 34 0 0
Distillation
T10 °C 331 217 217
T50 °C 343 263 -24 263
T90 °C 352 317 300
Specific Gravity 0.88 0.85 0.661 0.771
Viscosity cSt 6.0 2.6 0.227 @ 20°C 2.6
Oxygen % mass 11 0 34.74 0
Heating Value kJ/kg 37120 42424 29300 31983
15
16. Presentation Outline
Current status of EEC HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
16
17. Biodiesel Tests at SwRI- Hydrocarbon Emissions
Biodiesel Tests at SwRI- Hydrocarbon Emissions
B100 = 100% biodiesel
B20 = 20% biodiesel, 80% diesel
Oxygen in biodiesel reduces hydrocarbons
0.35
0.30
0.25
HC (G/HP-HR)
0.20
0.15
0.10
0.05
0.00
Cummins N14 DDC Series 50 Cummins B5.9
TEST ENGINE
17
B100 B20 Diesel
18. Biodiesel Tests at SwRI- CO Emissions
Biodiesel Tests at SwRI- CO Emissions
B100 = 100% biodiesel
B20 = 20% biodiesel, 80% diesel
2.5 Oxygen in biodiesel reduces hydrocarbons
2.0
CO (G/HP-HR)
1.5
1.0
0.5
0.0
Cummins N14 DDC Series 50 Cummins B5.9
TEST ENGINE
B100 B20 2D
18
19. Biodiesel Tests at SwRI- NOx Emissions
Biodiesel Tests at SwRI- NOx Emissions
6.0
5.0
4.0
NOx (G/HP-HR)
3.0
2.0
1.0
0.0
Cummins N14 DDC Series 50 Cummins B5.9
TEST ENGINE
19
B100 B20 2D
20. Effect of biodiesel fuels on particulates
PM versus Oxygen Concentration
0.12
2003 Detroit Diesel
Series 60 tested on US
0.10 heavy-duty transient
Diesel fuel test.
0.08
PM (g/hp-hr)
Biodiesel fuels show
0.06 significant particulate
reductions because of
0.04 higher oxygen content.
Biodiesel
0.02 SwRI SAE Paper
2005-01-3671
0.00
0 2 4 6 8 10 12 14 16 18
Oxygen Concentration (%m/m)
20
21. Effect of Biodiesel on Lubricity
800
High Frequency Reciprocating Rig (HFRR)
700 Biodiesel can
600 significantly improve
2% Biodiesel
500
lubricity of diesel
fuel, 2% specified in
(µm)
400
some parts of US.
300
200
DF2
100
DF1
0
0.01 0.1 1 10 100
Biodiesel (%)
21
22. Presentation Outline
Current status of EEC HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
22
23. Diesel Combustion
Start of Injection Controls Timing of Ignition
High Temp. Diffusion Flame Creates NOx
Incomplete Combustion in Fuel Rich Zones 23
Causes Soot Formation
24. Spark Ignition Combustion
Ignition Controlled by Spark Timing
High Temperature Flame Front Moves Through
Air and Fuel Mixture Creating NOx
24
Pre-ignition (knock) limits torque and efficiency.
25. HCCI
Fuel & Air Charge Undergoes Compression
Spontaneous Reaction Throughout Cylinder
Low Temperature Reaction Creates Low NOx 25
Neither diesel nor gasoline are ideal fuels
26. Only certain fuels are suitable for HCCI
EPAIT is Elevated Pressure Auto-Ignition Temperature; neither diesel or
regular gasoline have suitable EPAIT for HCCI
26
27. The Fuels Dimension
Full time HCCI on a ~1.1 liter/cylinder engine. A barrel of oil can yield
Engine driven supercharger more low-octane gasoline
Power limited by supercharger speed than high-octane.
Gasoline ~80 (R+M)/2
BSFC (g/kW-hr)
12
210
215
0.050 220
10 230
H-D Euro 6 proposed
240
0.040 at 0.50 g/kW.h NOx BMEP (bar) 260
8
NOx (g/kW.h)
280
0.030 300
345
0.020 6
0.010
4
0.000
0 200 400 600 800 1000 1200 2
BMEP (kPa) 1000 1250 1500 1750 2000 27
RPM
28. Presentation Outline
Current status of EEC HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
28
29. Zones in Rich-Low Temperature Combustion.
• LTC (Low Temperature Combustion)
• HCCI (Homogeneous Charge Compression Ignition)
• PCCI (Premixed Controlled Compression Ignition)
SAE 2001-0-0655 ; Toyota & ExxonMobil
6
5 Soot
Soot
Equivalence Ratio φ
A SAE 970873 ; Dec
4
A
B
Local
3
B
2
C
D D
1 C
NO
NO 6
0
1400 1800 2200 2600 3000
29
Local Temperature K
31. Diesel Tier II Bin 5/2 without NOx aftertreatment?
3 liter, 4 cylinder engine, 1958 kg SUV 4 speed AT
cycle emissions simulated from steady state measurements using RAPTOR™
vehicle model.
Bin 5 Bin 2 Engine out Miles/
120,000 120,000 NOx Gallon
miles miles (g/mile)
FTP75 NOx limit NOx limit
composite US06
FTP75 0.070 0.020 0.022 26.0 composite
US06 0.140 0.140 0.121 19.9
18
12
RAPTOR Sim ulation Steady-state full load
16 curve
SwRI representation
10 8
14
NGD3.0E Engine
BMEP (bar) for
8 12
BMEP (bar)
5
10 6
7 Standard/PCCI
6 Standard/PCCI
8
4 2
6
4 6
5
2 7
4 3 RAPTOR Simulation
2
LTC (LPL EGR) SwRI Representation
3 2 4 LTC (LPL EGR)
FTP-75 Cycle 1
1 LTC (HPL EGR) LTC (HPL EGR)
0 0
500 1000 1500 2000 2500 3000 500 1000 1500 2000 2500 3000 3500 4000 4500
Engine Speed (rpm ) Engine Speed (rpm) 31
32. Presentation Outline
Current status of EEC HD Legislation
Diesel fuel properties and their effect on emissions
Bio-diesel and its effect on emissions.
HCCI Status
Light-duty Diesel
High Efficiency Gasoline
32
33. Progress on High Efficiency Gasoline – 4.5L
Engine
1800 0.07
Excellent Load Range
1600 BMEP 0.06
BMEP (kPa), BSFC (g/kW-hr)
Engine-Out BSNOx (g/kW-hr)
Emissions potential 1400 0.05
very good. Ultra-low 1200 0.04
NOx with HC and CO
1000 0.03
typical of SI ranges
800 NOx 0.02
Key technologies: 600 0.01
1. EGR 400 bsfc 0
207 210 209 214 220
2. Boost 200 -0.01
3. High Compression
0 -0.02
4. Advanced Ignition
1000 1400 1900 2400 2900
5. Controls
Engine Speed (rev/min)
Peak loads demonstrated to 18 bar, with good engine speed
range. Fuel consumption diesel-competitive. Engine-out NOx 33
well-below any production system. 3-way catalyst-capable for
full engine operating range.
34. High Efficiency Gasoline Technology
Development
ISFC Sensitivity to EGR at 8 bar BMEP, 45'C
205
Engine stability
200 maintained.
Igniter #1 COV < 5%
195 Igniter #2 Traditional
ISFC (g/kW hr)
190
Igniter #3
185
Improved fuel
economy at high
180
EGR Levels
175
Plasma
25 30 35 40 45 50 55
% EGR
34
Extensive Igniter Studies to identify/develop new, high-
performance, reliable, and durable ignition systems.
35. Diesel vs. Gasoline Engine Costs
6 liter Medium-Duty Engine
High efficiency gasoline is less costly than diesel engine
technology:
Remove SCR -$2,500
Remove Catalyzed DPF -$2,000
Remove Common Rail Fuel System -$1,000
Add variable valve timing +$200
Add High Energy Ignition +$150
Add EGR Distribution +$150
Add 3-way Catalyst +$250
Net Gasoline saving +$4750
35
36. Summary
Bio-diesel has advantages in engine emissions and durability over
petroleum based fuel.
Low temperature diesel combustion may allow NOx aftertreatment to
be avoided.
Full time HCCI is possible with low octane gasoline.
The high efficiency gasoline engine can almost meet the
performance and fuel economy of the diesel at much less cost.
36
