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Clean Diesel and After-Treatment Systems
Gary M. ParsonsGlobal OEM and Industry Liaison ManagerFebruary 1, 2009
Presentation Overview
!U.S. Emissions Requirements" Drivers of new technologies
!Common Rail Injection!Diesel Particulate Filters
" Regeneration Strategies" Plugging
!Biodiesel Fuel Dilution !Critical Biodiesel Properties To Avoid DPF Plugging!NOx After-Treatment!Summary
Particulate, g/hp-hr
1988
1991
1994
1998
2002
NO x
, g/h
p-hr
0 0.1 0.70.60.50.40.30.20
2
12
10
8
6
4
1990
Progression of US Highway Heavy Duty Emissions Requirements
2007/2010
1988 to 2010
~98% reduction in NOx~99% reduction in PM
Impact of HD Soot Emissions Regulations in the US
Los Angeles
NewYorkCity
20070.01g/Bhp-Hr
2,853 miles
47 miles
19880.6g/Bhp-Hr
285 miles
19940.1g/Bhp-Hr
114 miles
19910.25g/Bhp-Hr
Particulate Matter
Relative Contribution of Particulate Matter of HD Diesel On-Road Engines – 1988 Versus 2007
1988475 pounds of P.M. in 120,000 miles 2007
9 pounds of P.M. in 120,000 miles
Photos Courtesy of Freightliner Trucks
Light Duty Gasoline and Diesel Must Now Meet The Same Emissions Regulations
! Both diesel and gasoline need to meet the same Tier 2 Bin 5 requirement! Diesel fuel price and exhaust after-treatment differential presents the
most significant barrier for light duty diesel engines in US vehicles
FTP 75 cycle, (g/mi) CO NOx NOx PMdiesel gasoline
Tier 1phased in 1994-97 4.2 1.25 0.6 0.10100.000 mi useful life
Tier 2 EPA binphased in 2004-09 7 4.2 0.02120.000 mi useful life 6 4.2 0.02
5 4.2 0.014 2.1 0.013 2.1 0.012 2.1 0.011 0 0.00
OEM Fleet avg NOx, maxAdditional standards for NMOG (Non-Methane Organic Gas) and HCHO (formaldehyde)
0.07
US Federal Emission StandardsPassenger Cars
0.070.040.020.00
0.200.150.07
• California LEV 2 is similar to EPA Tier 2 bin 5
EGR Advanced Injection System
Partnership – A NecessityFuels, Lubricants, Additives and After-treatment to Achieve Diesel Emissions
Targets
Engine
Diesel Particulate Filters
Ultra-Low Sulfur Diesel Fuel
EngineOil
Lubricity and Cold Flow Additive
Engine Oil Additives
Oxidation Inhibitors
Low SAPsHeat Tolerance
Low Ash
Volatility
Base Oil Change
NOx abs
DeNOx cat
SCR
Low Sulfur• Fuel• Base Oil • Additive
Low Phosphorous• Additive
Urea• Additive
Emissions Catalysts
Low Emissions
U.S. Reducing Diesel Fuel SulfurDirect Correlation With PM Emissions
1993
June 2006
5,000 ppm
500 ppm
2010 15 ppm On and Off Highway
Off Highway500 ppm
95% On-Highway15 ppm
To Reduce Particulate and for Compatibility With Diesel Particulate Filter (DPF)
CI-4PLUS
2002
Fuel Sulfur Levels, Hardware Changes, and Engine Oils Have Had To Change To Meet Regulations
19881990
19911994
19982000
20100.6
0.250.1
0
2
4
6
8
10
12
NO
x,g
/B
HP
-Hr
Particulate, g/BHP-Hr
10.710.7
6.06.05.05.0
5.05.0
4.04.0
2.02.0
.2.2
.01
2007
1.21.2
CJ-4
CG-4CF-4
CE
CH-4
CI-4
500-5,000 ppm
500 ppm max
15 ppm max
Alternate Emissions Technology Solutions to Meet On-Highway Emission Limits
HD Exhaust Emission Standards
0.00
0.05
0.10
0.15
0 1 2 3 4 5 6 7
NOx (g/kWh)
Parti
cula
te M
atte
r (g/
kWh)
1996 Euro 2
2000 Euro 3
US 2004
2005 Euro 4
2008 Euro 5
US 2007
De-NOx
DPF
US 2010
SCR
NOx/PM trade-off
G9801035
Lowering NOx Through In-Cylinder TechniquesExhaust Gas Recirculation (EGR)
Cooled EGRCooled EGR
In-Cylinder TemperatureIn-Cylinder Temperature
No EGREGR
TDC
Common Rail Direct Injection For Improved CombustionReduced Emissions and Better Fuel Economy
Common RailSupply Pump
InjectorECU
Source : DENSO Home page
Common RailSupply Pump
InjectorECU
Source : DENSO Home page
# Precise fuel control#Working pressures to
32,000 psi # 1µM plunger clearance.
Human hair is ~50 µM#Fuel cleanliness critical
Diesel Particulate Filters (DPF) to Meet PM RequirementsHeavy Duty Trucks 2007 & Passenger Car 2009
Part
icul
ate
(g/k
Wh)
Heavy Duty Emissions Standards
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 1 2 3 4 5 6 7NOX (g/kWh)
19911991
1998199820022002
2007200720102010
19941994
DieselParticulate
Filter (DPFs) on All Diesels
© Copyright Johnson Matthey Pic 2005
Diesel Particulate Filter (DPF) ShownWith Wall-Flow Filter Substrate
EngineExhaust
CleanExhaust
Removes ~ 97% of Particulate (Carbon)
Diesel Particulate Filter Chemical Reactions
2NO + O2 $ 2NO2 (~500 deg F)PM + O2 $ CO2 +H2O (~1,000 deg F)2NO2 + 2C $ N2 +2CO2
Auxilary Fuel Burner System to Heat Exhaust
Gas
Active Regeneration Diesel Particulate Filter (DPF)
EngineExhaust
© Copyright Johnson Matthey Pic 2005
CleanExhaust
or
or
Late Post Injection With Common Rail Fuel System
Fuel Injection to Heat
Exhaust Gas
DPF Regeneration With Dosing InjectorSystem Used In Most Heavy Duty Truck Applications
• 2 Fuel Lines (~250 psi)• 2 Coolant Lines (in/out)• 1 Air Line • Spark Plug Igniter
2007 Caterpillar ACERT On-Highway Engine ConfigurationCombustor for DPF Regeneration
Combustor For Manual DPF Regeneration
Late Post-Injection in DPF Vehicles Leads to Higher Levels of Fuel DilutionMultiple Injection Strategy to Control Combustion
Source: Robert Bosch GmbH
• Late post injection is typically used in light duty diesels equipped with Diesel Particulate Filters (DPF)
Crankcase Fuel Dilution With BiodieselProperties of Biodiesel Lead to Higher Fuel Dilution Levels Than Mineral Diesel
Late post-injection leads to higher levels of fuel dilution
Diesel – normal droplet size
Larger fuel spray droplet size
22.5
25.4
15
20
25
30
Diesel RME Biodiesel
Surface Tension
0.852
0.874
0.8
0.83
0.86
0.89
Diesel RME Biodiesel
Specific Gravity
1.3
2.4
0
1
2
3
Diesel RME Biodiesel
Viscosity, cSt at 100°C
Late Post Injection Leads to Higher Levels of Fuel Dilution
Conventional Injection Timing
LatePost-Injection
Increased Wall Wetting
Fuel Enters Crankcase
Crankcase Fuel Dilution With Biodiesel
Higher and Narrower boiling range of biodiesel makes it more persistent once it enters the crankcase
0
2
4
6
8
10
12
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Carbon number
Mas
s %
Mineral Diesel
Soy Methyl Ester
0
20
40
60
80
100
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Carbon Number
Mas
s %
• OEMs have reported 15-20% fuel dilution (FAME) at oil drain• OEMs often reduce drain intervals when Biodiesel blends are used
Source: Volkswagen
Oil Dilution During Particular Trap Regeneration
DPF Collects Lubricant Derived Materials
AshDetergent and Inhibitor
Base Oil
VIImprover
VIImprover
“Clean Air”“Clean Air”
• Impurities and ash forming compounds in diesel fuel collect in the DPF too
DPF Service Life
! For Heavy Duty Trucks, EPA has mandated a minimum DPF servicing interval of 150,000 miles and a minimum DPF life of 435,000 miles (10 years or 6,000 hours)" Soot may be eliminated through oxidation" Ash must be physically removed" Engine makers are responsible for DPF maintenance cost if
maintenance cycle less than 150,000 miles
Critical Biodiesel Properties and Specifications DPF Ash Loading
EN 145385 maxSodium and Potassium, Combined
D 49510.001 maxPhosphorous Content
D 45300.050 maxCarbon Residue
D 8740.02 maxSulfated Ash
D 27090.05 maxWater and Sediment
EN 145385 maxCalcium and Magnesium
Test MethodASTM D6751 Limits
Property
NOx Emissions Control TrendsU.S. Off-highwayEmissions Standards 130<kW<225 (175<hp<300)
0.30
0.20
0.10
00 1 2 3 4 5 6 7
NOx g/bhp-hr
Particulate g/bhp-hr
8 9
0.40
0.50
0.60
Tier 4 will require ULSD & exhaust after treatment
Tier 1 - 1996
Tier 4 - 2012=>2014 Tier 2 – 2003Tier 3 - 2007
The combination of•EGR•SCR & Urea (or NOx Adsorber, Light Duty Diesel)
•TC – Two Compressor (Turbo’s)
and Two Intercoolers
Alternate Emissions Technology Solutions to Meet On-Highway Emission Limits
HD Exhaust Emission Standards
0.00
0.05
0.10
0.15
0 1 2 3 4 5 6 7
NOx (g/kWh)
Parti
cula
te M
atte
r (g/
kWh)
1996 Euro 2
2000 Euro 3
US 2004
2005 Euro 4
2008 Euro 5
US 2007
De-NOx
DPF
US 2010
SCR
NOx/PM trade-off
AqueousUreaSolutionTank(Diesel Exhaust Fluid - DEF)1
23
45
6
TPump and Injector
Atomized Urea Solution
Closed Catalyzed Particulate
Filter
SCR Catalyst
AmmoniaSlip
Catalyst
C
Two Stage Turbos and Two Stage Intercoolers
Common Rail Fuel System
Air toAir Cooler
EGR
In-Cylinder and After Treatment Systems for On- and Off-Highway Heavy Duty
Closed Crankcase
Exhaust Dosing
Injector
Exhaust Outlet
Compact DPF-SCR-Urea to Meet Particulate and NOx Standards
Urea Mixing Unit
Urea Injection Point With Wide Spray
Slip SCR SCR
Slip SCR SCR
DPFOxicat
Ammonia
Exhaust Inlet
Catalyst to Prevent Ammonia Release
Catalyst to Reduce NOx
Lean NOx Trap Being Used in VW Clean Diesels
" Lean NOx traps highly sensitive to fuel sulfur levels and other contaminants" Fuel economy penalty as fuel is consumed in after-treatment system
Diesel Exhaust After-Treatment Systems
#Worse fuel economy#Sensitive to sulfur#Reliability for HD applications
#No extra fluid required#Not sensitive to driving mode
Lean NOx Trap (LNT)
#Infrastructure for Diesel Exhaust Fluid (DEF)#Difficult to downsize#Doesn’t work well in city driving mode
#Good fuel economySelective Catalyst Reduction (SCR) -Urea
#Increased back pressure impacts fuel economy#Periodic maintenance to clean out ash#Fuel dilution when late post injection is used
#Scalable to all engine sizes and applications#Highly efficient
Diesel Particulate Filter (DPF)
NegativesPositives
Summary
! Emissions regulations are driving new hardware, fuels, and lubricants technologies into the market
! A systems approach is required in order to meet sometimes conflicting requirements simultaneously
! The introduction of Common Rail Injection systems has lead to reduced emissions, noise, and fuel consumption but requires very clean fuel
! Exhaust after-treatment devices are required to meet the latest Particulate Matter (PM) and NOx emissions requirements
! In-use compliance requirements can result in the OEM being responsible for emissions system performance for 10+ years
! Late-post injection can lead to elevated levels of biodiesel fuel dilution! Diesel Particulate Filters (DPF) require regeneration and can plug due to
ash forming compounds! The Energy Independence and Security Act of 2007 has a provision for
OEMs to capture CAFÉ credits if they produce B20 vehicles (similar to E85 credit for FlexFuel vehicles).