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Impacts of Advanced Combustion, Fuels and Aftertreatment Technologies on Diesel PM Emissions and Mobile Source Air Toxics:
A Ten-Year Retrospective
February 11, 2009
Chairman’s Air Pollution Seminar Series
Research Center [email protected]
Managed by UT-Battelle 865-946-1232 for the Department of Energy
California Air Resources Board
Sacramento, CA
John Storey Fuels, Engines, and Emissions
Acknowledgements
• FEERC team: – Ron Graves (Director), Brian West, Jim Parks,
Sam Lewis, Bruce Bunting, Stuart Daw, Scott Sluder, Robert Wagner, Teresa Barone, Norberto Domingo and many others
• DOE support: Office of Vehicle Technologies – James Eberhardt, Gurpreet Singh, Ken Howden,
Kevin Stork, John Fairbanks
• EPA support: OTAQ – Dennis Johnson and Jim Blubaugh
• CARB – Alberto Ayala for inviting me
2 Managed by UT-Battelle for the Department of Energy Presentation_name
Diesel and light-duty diesel have specific challenges in public, regulatory acceptance
•1970’s-90’s tough for diesel
•GM diesel problems
•“Dump Dirty Diesel” Campaign
•CARB interest in diesel replacement with natural gas
1979 Cadillac Diesel Sedan
3 Managed by UT-Battelle for the Department of Energy Presentation_name
•1998+ Government Response to Diesel Issues
•DEER conference
•Consent decree between OEMs, EPA
•Fuel sulfur rule
•EPA releases Diesel PM Toxicity
1981 VW Rabbit Diesel Pickup
Who invented the diesel engine?
• Rudolf Diesel 1858 -1913
• Much more efficient than steam engines of the time
• Original vision – to run on vegetable oils! – biodiesel isn’t such a
new idea
• Died mysteriously on ferry to England 1913
4 Managed by UT-Battelle for the Department of Energy Presentation_name
[ l
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
5 Managed by UT-Battelle for the Department of Energy Presentation_name
Oak Ridge National Laboratory • Began as part of the Manhattan Project
• Nation’s largest multiprogram energy Relevant Facilities laboratory
• World’s first nuclear reactor and now leading producer of medical radioisotopes
• Nation’s largest unclassified scientific computing facility
• Nation’s largest science facility, the $1.4B Spallation Neutron Source
• Nation’s largest concentration of open source materials research
6 Managed by UT-Battelle for the Department of Energy Presentation_name
National Transportation Research Center
High Temperature Materials Laboratory
Transportation technology
Storage and Consumption Generation distribution
Internal combustion
Alternative fuels
Hydrogen storage Hybrid and transport Electric
Vehicle
Refining
Hydrogen Batteries & production Power electronics Fuel cells
Transportation system analysis
7 Managed by UT-Battelle for the Department of Energy Presentation_name
Chassis dyno lab
Presentation_name
internal
Engine Cells
Chassis Dyno Lab
Analytical Labs
Offsite Projects
Fuels, Engines, & Emissions Research Center…. a comprehensive laboratory for combustion engine technology
• A DOE National User Facility in the NTRC
• Focusing on alternative fuels, advanced combustion, and emission control R&D
• Unique or extraordinary diagnostic and analytical tools for engine/emission control R&D
• R&D from bench-scale to vehicle – Chemical/analytical labs – 9 dynamometer stands: 25-600
hp – Chassis dynamometer – Full-pass engine controls
support research – Emissions analysis with high
resolution of time and species – Non-invasive optical and mass-
spec diagnostics – Modeling & simulation
8 Managed by UT-Battelle for the Department of Energy
FreedomC .. ~
FueJhrtnerlflip
The DOE’s Transportation Agenda
• Energy Security, Energy Efficiency – Energy Data Book and http://www.fueleconomy.gov – Energy Independence and Security Act (EISA, 2007)
• 36 Billion gal/yr of renewable fuels (2022) • Limits to corn-based ethanol • Focus on cellulosic ethanol
• Office of Vehicle Technologies – Light-duty engine efficiency goal: 42% (2007) 45% (2010) – Heavy-duty efficiency goal: 50% (2006); 55% (2013) – Meet applicable emissions
• Office of Biomass Programs – Production via Cellulosic sources (biomass)
• Office of Hydrogen, Fuel cells, and Infrastructure Technologies – Automotive fuel cell emphasis
9 Managed by UT-Battelle for the Department of Energy Presentation_name
IMI IIINS REIEIIDR
So why bring up the DOE vision?
• DOE saw diesel engines as meeting their goal of energy efficiency and security – Heavy-duty engine efficiency program – Light Truck Clean Diesel program
• Emissions control was the enabling technology for diesel
• 1998. DEER conference in Maine
10 Managed by UT-Battelle for the Department of Energy Presentation_name
– Diesel Engine Emissions control Research – Organized by DOE (John Fairbanks) – < 100 attendees
• 2008 DEER conference in Dearborn – > 1300 attendees
http://www1.eere.energy.gov/vehiclesandfuels/resources/proceedings/index.html
DEER conferences are comprehensive
• Industry, academia, National Labs, non-profit – Special session for environmental advocacy
organizations
• Thrusts included health effects – First U.S. discussion of nanoparticles and health
• NOx and PM control sessions
• Now large focus on advanced combustion and energy efficiency
11 Managed by UT-Battelle for the Department of Energy Presentation_name
Evolution of Heavy Duty Diesel Engine Emission Control
Source – Pat Flynn, DEER 2000
15
10
5
0
12 Managed by UT-Battelle for the Department of Energy Presentation_name
0 0.1 0.25 0.6 1.0
1974 EPA (HC + NOx)
1988 1978 (HC + NOx)
1990
1991 1994
1998
1987 Models Retard Timing Lower IMT Shorten HRR Low Friction
1988 Models Retard Timing Inc. Inj. Press Higher Boost Higher CR
1991 Models Retard Timing Low IMT/High IMP Inc. Inj. Press. Variable Inj. Timing
Particulate [g/(HP-hr)]
2004 (2002)
Cooled EGR
NO
x [g
/(H
P-h
r)]
EPA’s emissions standards require substantial PM and NOx reductions for automotive diesels, too.
13 Managed by UT-Battelle for the Department of Energy Presentation_name
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
FTP NOx Emissions (g/mi)
FTP
PM
Em
issi
ons
(g/m
i)
5
Bin 8
Tier 1, Through 2003
Tier 2 Standards Phase-in 2004-2009
Current iesel
Technology
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
14 Managed by UT-Battelle for the Department of Energy Presentation_name
0 •
How do diesels work, anyway?
Diesel Engine Gasoline Engine (compression ignition)
(spark ignited)
hot flame region:
nitric oxides +
fuel injector
hot flame region:
nitric oxides
spark plug
Source:Caterpillar, 2003smoke
15 Managed by UT-Battelle for the Department of Energy Presentation_name
R:ai I pressure sensor
Fuel tank
High pressure ·= =a-,1......._ .......... _"_
pump
\
ontrol n it
Delivery va lve
!Pumping chamber
Spill port
Plunger
IRoll,er tappet
Fuel line
Edge filter
Injector body
Spring
eedle
Nozzle
Fuel injection - key subsystem of diesel
• Pump-line-nozzle (“ancient”)
• Unit injectors
• Common rail (state of art)
• Piezo (combined with
common rail emerging)
Injector tip
Source: Dieselnet.com
16 Managed by UT-Battelle for the Department of Energy Presentation_name
Injection pressure being increased to aid emission compliance
One bar=14.5 psi
One Mpa=10 bar • Mechanical unit injector=1000 bar (1981)
• “HEUI” =up to 1450 bar
• Early generation common rail=1350 bar
• Latest piezo common rail=1800 bar
• The future (Bosch and others) 2000 bar = 29,000 psi
• WHY? – Tiny, tiny holes (<200 �m) needed to make a fine
spray, smaller particles – But , then pass ~ 1 gallon/hr through each hole!
17 Managed by UT-Battelle for the Department of Energy Presentation_name
TDC
Start of lnjec,ilon
IV:C 2
BOC
C"Ombusti 011
TDC
Crank Arngle
BOC
IVO 1
Sequence of diesel fuel injection and beginning of combustion
18 Managed by UT-Battelle for the Department of Energy Presentation_name
NOx PM Trade-off curve has been moving
PM
Em
issi
ons
(g/m
i)
0.16
0.14
0.12
0.10 Tier 1, Through 2003
0.08
0.06
0.04
0.02 Bin 8
Current iesel
Technology
50.00 0.0 0.2 0.4 0.6 0.8
NOx Emissions (g/mi)
1.0 1.2 1.4
19 Managed by UT-Battelle for the Department of Energy Presentation_name
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
20 Managed by UT-Battelle for the Department of Energy Presentation_name
Diesel PM control – Diesel Particulate Filters (DPF) and Diesel Oxidation Catalysts (DOC)
• DOCs use precious metal catalyst to burn off organic fraction – Typical PM mass reduction is 30% – Used on heavy-duty pickup trucks in 90’s
• First DPF on a car – 1985 Mercedes 300 for California market (not a success) – Need 700 °C to burn off soot with exhaust O 2
• Electrically-heated DPF’s in early 1990’s
• Early systems used DOC + DPF – NO → NO2, then the NO 2 oxidizes the soot
• Later DPFs use catalytic coating – Catalyst on DPF converts NO to NO 2, NO2 oxidizes soot
21 Managed by UT-Battelle for the Department of Energy Presentation_name
Diesel Particulate Filter uses ceramic honeycomb to trap PM
22 Managed by UT-Battelle for the Department of Energy Presentation_name
Trapped PM
Cell Plugs
Exhaust (PM, CO, HC) Enter
Ceramic Honeycomb Wall
Exhaust (CO 2, H2O) Out
Fifrter
Inlet Outlet
DPF Assembly can replace muffler
Inlet section with Soot filter Outlet section Pre-catalyst flow distributor substrate with water trap
flow flow
V-band + V-band + V-band + gasket gasket gasket
23 Managed by UT-Battelle for the Department of Energy
Figure 14, temperature I regeneration line, winter NYC
100 C: 0 90 ~ 80 Cl) C: Cl) 70 C) Cl) ... 60 .c: --~ 50 rn 40 C: ::::, ... 30 -0
:::l::: 20 0
_,.._ :~:68-
/ .,V
/ /"
/ /
/ /4
/ .~ ,~
~ n
03 M!O j M4 -
10
er◄ 280 290 300 310 320 330 340 350 3E
10% temperature, deg.C
Early DPF field study in 2001 in NYC
Uncontrolled Regeneration
• Occurs when DPF accumulates excess soot
• Excess soot can be lit off during high load (hill, ex-way).
• If engine drops to idle during this burning, exhaust flow too low
• Internal DPF temperatures high enough to melt ceramic.
Source: B. Bunting, DEER 2001
24 Managed by UT-Battelle for the Department of Energy Presentation_name
TTRRAAPP FFAAIILLUURREE,, BBUUSS 66335588,, 22//2266//0011
11000000 10
TTEE
MMPP
EERR
AATT
UURR
EE,,dd
eegg..CC
990000880000 8770000660000 trap in C6550000 trap out C440000 press inhg4330000220000 22110000
00 00
44::3333
::1100
44::3388
::1100
44::4433
::1100
44::4488
::1100
44::5533
::1100
44::5588
::1100
55::0033
::1100
55::0088
::1100
55::1133
::1100
55::1188
::1100
55::2233
::1100
55::2288
::1100
55::3333
::1100
55::3388
::1100
55::4433
::1100
55::4488
::1100
55::5533
::1100
TTIIMMEE OOFF DDAAYY
Trap failure is very rapid, typically
TRAP FAILURE, BUS 6358, 2/26/01
1000 10
TE
MP
ER
AT
UR
E, d
eg.C
900 800 8 700 600 6 trap in C 500 trap out C 400 4 press inhg 300 200 2 100
0 0
4:33
:10
4:38
:10
4:43
:10
4:48
:10
4:53
:10
4:58
:10
5:03
:10
5:08
:10
5:13
:10
5:18
:10
5:23
:10
5:28
:10
5:33
:10
5:38
:10
5:43
:10
5:48
:10
5:53
:10
Source: B. Bunting, DEER 2001TIME OF DAY 25 Managed by UT-Battelle
for the Department of Energy Presentation_name
What we are trying to prevent -Uncontrolled Regeneration
What we are trying to prevent -Uncontrolled Regeneration
Hi Temp - Melting
Temp Gradients - Fracture
Low load operation Excessive soot loading
High load operation ignites soot UNCONTROLLED REGENERATION
26 Managed by UT-Battelle for the Department of Energy Presentation_name
Solution: active regeneration controls when the DPF is regenerated
Configuration 1 Soot filter with catalyst
Exhaust Outlet
Diesel injection
Configuration 2 Pre-cat Soot filter with catalyst
Exhaust Outlet
Diesel injection
More of a slow burn than a flame thrower
27 Managed by UT-Battelle for the Department of Energy Presentation_name
………..Evolution into a system…
• Gasoline vehicle emissions control evolved into a system – Tailpipe approach with oxidation – early 70’s – Air pumps added, late 70’s – A/F ratio control + fuel injection – 80’s – Now completely tied together
• Diesel engine system – – DPF with Active Regen – EGR for NOx control
28 Managed by UT-Battelle for the Department of Energy Presentation_name
Better control of fuel injection
Fuel – the missing link
• DPF development well on its way by 2001 – But PM mass was higher with pump fuel
• Sulfur was the culprit – made sulfate aerosol in the exhaust pipe
• DOE had several large research efforts to address sulfur effects 1999-2002 – DECSE (Diesel Emissions Control- Sulfur Effects) – DVECSE (Diesel Vehicle Emissions Control – SE)
• Result: EPA required 15 ppm S in 2006
• Analogous to tetraethyl lead removal – Driven by concerns for catalytic converter – Lower lead levels in people was a byproduct
29 Managed by UT-Battelle for the Department of Energy Presentation_name
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
30 Managed by UT-Battelle for the Department of Energy Presentation_name
- - - .. -.: . ,-
The dirty diesel of the past is giving way to clean diesel technology
31 Managed by UT-Battelle for the Department of Energy Presentation_name
2008 Dodge Ram 2500 Pickup meets 2009 standards
ter
clDeNOx / Aclva lilCe - nverter cataly1i!c co
BLUETEC
Presentation name
Clean diesel cars available now
32 Managed by UT-Battelle for the Department of Energy _
VW Jetta TDI
Mercedes E320 Bluetec
High pressure EGR tube
EGR cooler
EGR valve Low pressure EGR tube
DPF
Turbocharger with adjustable guide vanes
Inlet mixing nozzle
VW’s emissions controls a marvel of packaging
Source: Internationales Wiener 33 Managed by UT-Battelle
for the Department of Energy Presentation_nameMotorensymposium 2008
I I
Almost 40% improvement in MPG
2009 Volkswagen Jetta 2009 Volkswagen Jetta
Diesel Vehicle Gasoline Vehicle
New EPA MPG
DIESEL REGULAR GASOLINE
33 24 Combined Combined 29 40 20 29
City Hwy City Hwy
Annual Petroleum
Consumption (1 barrel=42 gallons) 11.9 barrels 14.3 barrels
Source: fueleconomy.gov 34 Managed by UT-Battelle
for the Department of Energy Presentation_name
Diesel fuel then and now…
• 1998: Low sulfur diesel rule in effect, largely for PM control. < 500 ppm S, ~450 ppm true – California: ~150 ppm S due to low aromatics
• 2006: Ultralow sulfur diesel for diesel emissions control < 15 ppm S, ~ 8 ppm true – How? The magic of hydrogen. Result is higher
cetane fuel - good for older engines
• Biodiesel: How does it affect PM emissions? – Generally lower PM mass, higher solubles – Alters behavior of DPF → ULSD ≠ B5 ≠ B20
35 Managed by UT-Battelle for the Department of Energy Presentation_name
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
36 Managed by UT-Battelle for the Department of Energy Presentation_name
Diesel PM retrofit
• Diesel oxidation catalysts (DOC) popular – Low cost, “bolt-on” solution – ~30% PM reduction
• Diesel Particulate Filters (DPF) offer best PM removal – Require maintenance, off-vehicle regeneration
• Crankcase emissions filtration – Crankcase breather significant source
• ORNL-EPA project examined both – Field-aged DPF from schoolbus – Crankcase PM mass and size
37 Managed by UT-Battelle for the Department of Energy Presentation_name
----•-
ged by UT-Battellee Department of Energy Presentation name
Extensive setup of 1999 Cummins B5.9 was necessary to carry out project
38 Mana for th _
Engine
DPF
Transient Emissions
System
PM and HC go down with DPF E
mis
sion
s (g
/hp.
hr)
39 Managed by UT-Battelle for the Department of Energy Presentation_name
0.0020 0.0035 0.0066 0.0055
FTP1 FTP2 FTP3 BP-FTP1
BP-FTP2
DPF-FTP1
DPF-FTP2
CDPF-FTP1
CDPF-FTP2
Test Sequence
PM HC
0.5
0.4
0.3
0.2
0.1
0
• 0 • •
I • I • • • • , ,. •• ,
• 0
• •
Total Particle Number Concentration During FTP Cycles
atio
n3 )
(#/
cm
12000
10000
8000
Downstream of DPF Hot FTP 1 (09/04/08) Hot FTP 1 (09/05/08)
Outdoor Air Concentration
Con
cent
r
6000
4000
Num
ber
2000
0 0 300 600 900 1200
Time for FTP (sec) 40 Managed by UT-Battelle
for the Department of Energy Presentation_name
Unique sampler design imposes no vacuum or pressure on crankcase
• All of PM collected
• �p < 0.5” H 2O observed at inlet of tunnel
• PM as much as 18% of regulated limit
To Roots Blower + Flow Measure
Pressure Measurement
SMPS outlet
HEPA Filter
Twin 70mm Filter Holders
41 Managed by UT-Battelle for the Department of Energy Presentation_name
□ ■ □
-
□ ~
■
- ~
- ~
• I ■ I I ■ • I ■■ I ■ I ■■ I ■ I ■■ I ■ • I ■ • I ■ • I ■ • I ■ • ■ ■ I I ■■
- ~
PM emissions from draft tube significant
42 Managed by UT-Battelle for the Department of Energy Presentation_name
7/01
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1
7/01
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7/03
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7/02
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7/02
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7/08
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8/25
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1
8/25
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2
8/25
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3
8/27
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8/27
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2 9/
03 cf
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9/04
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9/
04 h
ftp1
9/04
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9/05
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stea
dy-s
tate
2000
rpm
, 23
bar
1400
rpm
, 30
bar
1800
rpm
, 30
bar
805r
pm, 0
bar
0
0 . 0 5
0 . 1
0 . 1 5
0 . 2
0 . 2 5
Cra
nkca
se P
M (
g/hr
)
B a s e w . B p w . D P F S t e a d y S t a t e I d l e
*
Cra
nkca
se P
M (
g/hp
.hr)
0.025
0.02
0.015
0.01
0.005
0
" I\ ' . • • • • • • • • . ' : ' • • •
• 0
Crankcase Emissions Engine Baseline 2.5e+8 Number-Size
SMPS Distribution
Rated Torque 1400 RPM, 300 ft.lbs
(similar to 100% A on 13 mode)
dN/d
logd
p (#
/cm
3 ) APS 2.0e+8
µg = 114 ± 2 nm Ctot 1.5e+8 = 2.9 x 107 #/cm3
1.0e+8
5.0e+7
Increased Backpressure 2.5e+8
0.0 100 101 102 103 104 105
SMPS dp (nm) APS 2.0e+8
µg = 159 ± 2 nm Ctot = 1.4 x 108 #/cm3
1.5e+8
1.0e+8 Backpressure 280 mbar at rated speed (1400 RPM)
5.0e+7
0.0 101 102 103 104 105
dN/d
logd
p (#
/cm
3 )
43 Managed by UT-Battelle for the Department of Energy dp (nm)
Presentation_name
Findings from Retrofit DPF Study
• Field aged DPF (3+ years in service) as received evaluation – DPF very efficiently removing PM – Clean DPF: higher number concentrations until soot layer
builds
• Crankcase emissions – mostly oil droplets – PM mass emissions = 3 X DPF out emissions – PM size shows significantly larger particles
• Crankcase PM treatment complements DPF retrofit
• Model Year 2007 and beyond closes the crankcase
Presentation at 2009 CRC On-Road Emissions Workshop
44 Managed by UT-Battelle for the Department of Energy Presentation_name
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
45 Managed by UT-Battelle for the Department of Energy Presentation_name
Tcool Tmax
I I
Tadiabatic
...,._ Flame Front
1ii!i."I b~l~tlJllJ ij(>"V l.;4' f»:» V,\JJ, ~
1 C'.ICT 2 o:rcr J DJC7
, C'.ICT ; o:rcr
S o:ri:r I r;:i,;;:7
~ c:rcr - q°"DJCT
1'.I C'.ICT
T-Battelle
Modeling used extensively to improve combustion efficiency, emissions
46 Managed by U for the Department of Energy Presentation_name
Addressing the fundamental losses of combustion flames
Increased use of computational tools
Catalyst Modeling takes off from 2000 on….
Cross-Cut Lean Exhaust Emissions Reduction Simulations
• Objective to improve ability to simulate advanced emissions controls
• CLEERS (cleers.org ) has annual workshops and working groups for NOx and PM control
• Broad participation from industry, academia, labs
• Past presentations available on the web site – Created and maintained by ORNL
47 Managed by UT-Battelle for the Department of Energy Presentation_name
- __ J ___ ~---1 I
~-~--~--➔---+---
1 I I I ---1---7---,--- --c ---_I __ I __ I __ I __ _
I I I I I ~ I --+---~~~ --:---
1
I
µµ µ
Modeling Extended to Engines, Vehicles
8 16 Soot layer Width7 14
Soo
t Lay
er W
idth
(µm
)
6 Engine-out PM
12
5 10
4 8
3 6
2 4
1 2
0 0 0 1372 2744 4116 5488 6860
Time (s)
Eng
ine-
Out
PM
(mg/
s)
•Modeling the growth of the soot layer in a DPF during a drive cycle Source: ORNL Systems Modeling, 2008•No active regeneration of the filter (DPF)48 Managed by UT-Battelle
for the Department of Energy Presentation_name
[~-----~]
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
49 Managed by UT-Battelle for the Department of Energy Presentation_name
High Efficiency Clean Combustion (HECC)
• HECC includes – Homogeneous Charge Compression Ignition (HCCI)
– Premixed Charge Compression Ignition (PCCI)
– others
• Improve powertrain system efficiency by lowering performance requirements for post-combustion emissions controls.
Objectives of ORNL efforts
• Detailed emissions characterization for understanding combustion regimes and environmental impact.
– Hydrocarbon speciation (MSATs!)
– PM characterization
50 Managed by UT-Battelle for the Department of Energy Presentation_name
Exhaust Gas Recirculation (EGR) key to advanced combustion modes
• EGR on most diesel engines since 2002
• How does EGR work? – Lowers NOx by diluting charge (air) with exhaust gas
– lowers peak combustion temperature
– Typically increases PM
• High levels of EGR result in lower NOx and PM
51 Managed by UT-Battelle for the Department of Energy Presentation_name
t
► ~--~
Engine C
oolant
Shaft W
ork
HP EGR HXN
DP
F
Turbo
Exhaust
Air H
XN
Typical E
xhaust Gas
Recirculation (E
GR
) A
ir
scheme
52 M
anaged
by U
T-B
attelle fo
r the D
epartm
ent o
f En
ergy
Presen
tation_n
ame
18
1.20 16
14 ai,,. 1.00 ai,,. .c 12 .c
I I C. C. .c .c en 0.80 10 --en :E u D.. 8 :::c .. 0.60 I->< co .. 0 6 0 z 0.40 u
4
0.20 THC 2
PM 0.00 0
20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0
EGR%
NO
x,P
Mg/
hp-h
r
0.4
055.045.035.025.0 50.040.030.020.0 60.0
EGR %
Motivation – 1999 study with VW TDI engine N
Ox,
PM
g/h
p-hr
0.4
0
1.0
1.4
PM
NOx1.0
1.4
PM
NOx
25.0 35.0 45.0 55.020.0 30.0 40.0 50.0 60.0
EGR %
53 Managed by UT-Battelle for the Department of Energy Presentation_name
~ ~ 0
~~ ~ 0
• ·~ :~~2:~~ ~ r ~
' ~ ~ •~ ~~e~ ~ ~ ~ +*~>1<<1-<I-+ ~ ~ ~ ~ ~ .
~ ~ ~ ~ ~ ~ I ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ J ~ ~ I j - i I ~ ~ ~ ~ I
0 •
What is this High Efficiency Clean Combustion?
Diesel Engine Gasoline Engine HCCI Engine
(compression ignition) (spark ignited) (Homogeneous Charge
Compression Ignition)
spark plug
hot flame region:
nitric oxides
Source:Caterpillar, 200354 Managed by UT-Battelle
for the Department of Energy Presentation_name
hot flame region: nitric oxides + smoke
fuel injector
Low temperature combustion
ultra low emissions !!
Images of Conventional and HCCI Source: Caterpillar, DEER Conference, 2002
55 Managed by UT-Battelle for the Department of Energy Presentation_name
Conventional Diesel HCCI
PCCI = Pre-mixed charge compression ignition
~ •• • • . _, ,._ ________ _
0.16
Advanced combustion changes the NOx-PM trade-off curve
0.14
0.12
Tier 1, Through 2003 0.10
With 0.08 “advanced”
combustion 0.06
Current iesel
0.04 Technology Bin 8 0.02
Tier 2 Standards Phase-in 2004-2009 50.00
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
FTP NOx Emissions (g/mi)
FTP
PM
Em
issi
ons
(g/m
i)
56 Managed by UT-Battelle for the Department of Energy Presentation_name
--00 1000 1500 2000 2500 3000 3500
02
13
4
5
Steady state modes used with HECC to approximate Light-duty FTP cycle.
• BSFC equivalent to What about HCs and CO? baseline operation.
15.0 • Emissions lower
5.0
10.0
5
Engine Speed (rpm)
BM
EP
(ba
r)
0.0
0.5
1.0
NOx PM Conventional
HECC
Estimated FTP Emissions Index (Normalized)
57 Managed by UT-Battelle for the Department of Energy Presentation_name
0
□
■
□
□
■
High EGR = high formaldehyde and acetaldehyde formation.
58 Managed by UT-Battelle for the Department of Energy Presentation_name
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
22.2 34.9 40.2 44.3 46.3 48.8 54.0 56.0
EGR %
DN
PH
Mas
s C
once
ntra
tion
mg/
s
Formaldehyde Acetaldehyde Acrolein
Propionaldehyde Benzaldehyde
11 I I I '-1 I \_ I I
I I I I I I I I I I I
What are Mobile Source Air Toxics (MSATs)?
59 Managed by UT-Battelle for the Department of Energy Presentation_name
Mobile Source Air Toxics (MSATs)
Particulate Matter (PM)
Volatile Organics
Semivolatile Organics
Metals Diesel PM
Polycyclic organic Matter (POM)
Formaldehyde
Acetaldehyde
1,3-Butadiene
Acrolein
Benzene
Toluene
Ethylbenzene
Xylene Polycyclic Aromatic
Hydrocarbons (PAHs)
Diesel Exhaust Organic Gases
Array of Analytical Techniques for MSATs
Total PM SOF/insoluble SOF speciation
Dilution PM Filters
Tunnel SMPS Particle Size Distribution
Catalyst
60 Managed by UT-Battelle for the Department of Energy
Empore Selective capture of semi-volatiles (C10-C18)
GC/MS speciation
DNPH
Selective capture of carbonyl species
HPLC, UV, ESI/MS separation/speciation
Presentation_name
FTIR
C1-C4 species
Canisters
Light HC species
Preconcentrator, GC/MS speciation
DOC Oxidation of Formaldehyde Not Complete Until ~225ºC
• CO, HC, and formaldehyde 100 oxidation efficiency as a 90 function of catalyst temperature 80
– CO oxidation enables higher 70 oxidation of HCs and formaldehyde
– Formaldehyde oxidation not complete until 225ºC C
onve
rsio
n
60
50
40
30
20 • Engine at 1500 rpm/ 1.0 bar during cool down of catalyst 10
from previous higher load 0
operation 125 150 175 200 225 250
Catalyst Temperature (C)
CO HC Formaldehyde
• Thermal management can enable DOC to be kept at temperature where suitable CO/HC/Formaldehyde oxidation occurs, but…
– What is the efficiency penalty associated with maintaining formaldehyde oxidation vs. CO/HC oxidation?
61 Managed by UT-Battelle for the Department of Energy Presentation_name
■ □
■ ■
- ■
■
5
Low catalyst temperature presents challenges for tailpipe aldehydes in PCCI mode
1500 rpm, 1.0 bar
5Conv., Engine Out
3
119ºC
Catalyst Temperature
2E
mis
sion
s In
dex
(g/k
g fu
el)
PCCI, Engine Out PCCI, Catalyst Out
4
Tier 2, Bin 5 formaldehyde regulation 0.24 g/kg fuel 1
02000 rpm, 2.0 bar
Formaldehyde Acetaldehyde5
220ºC
Formaldehyde Acetaldehyde
1500 rpm, 2.6 bar
256ºC
Em
issi
ons
Inde
x (g
/kg
fuel
)
Em
issi
ons
Inde
x (g
/kg
fuel
)
44
33
2
1
0 62 Managed by UT-Battelle
for the Department of Energy Presentation_name Formaldehyde Acetaldehyde
2
1
0
an Union adopting number bas
nvestigating number-based sy
Particle size measurements
• Why measure particle size? – Nanoparticles linked to health effects
– Number of particles may be more important than mass
• Modern engines reduce PM size to reduce mass
• With DPFs, PM mass measurement difficult – Europe
– CARB i
Presentation_name
ed regs
stem as well
Engine out DPF out
63 Managed by UT-Battelle for the Department of Energy
• •
r, . \ I • I • .. I
I I
I. dN/d
logd
p (#
/cm
3 ) PCCI PM smaller in size at low load and medium load
8e+7 Conv.: Engine Out PCCI: Engine Out Number s are similar,
but PCCI particles much smaller
dN/d
logd
p (#
/cm
3 )
6e+7
4e+7 23 nm 46 nm
2e+7
8e+7 Conv.: Engine Out PCCI: Engine Out 0
6e+7 1 10 100 1000
dp (nm)
4e+7 Number of particles > 100 nm decreases
2e+7
0 1 10 100 1000
64 Managed by UT-Battelle for the Department of Energy dp (nm) Presentation_name
The path forward…..
• Motivation, background of DOE and diesel
• Approach to lowering PM – Engine Hardware – Diesel Particulate Filters
• Current State-of-the-Art – Putting it all together into today’s vehicle – Retrofit PM control – Ultralow sulfur diesel and Biodiesel
• Future – Modeling Emissions Control Systems – Advanced combustion modes – Link to CO 2 emissions and climate change
65 Managed by UT-Battelle for the Department of Energy Presentation_name
What does all of this mean for greenhouse gas emissions?
• CO2 directly related to fuel efficiency – Engines have been getting more efficient, but..
– …PM emissions controls reduce efficiency • Backpressure, fuel needed for active regeneration
• N2O and CH4 emissions can be a concern – Catalyst systems can make N 2O
– Advanced combustion can make more CH 4
• 2010 regulations could be paradigm shift – Urea-SCR NOx removal efficiency could allow
higher fuel efficiency
66 Managed by UT-Battelle for the Department of Energy Presentation_name
Summary
• Engines, PM control have advanced considerably in ten years
• DPFs close to 99% efficient
• Retrofits showing good durability
• Packaging of systems remains a challenge
• DOE continues to push technology for better efficiency
67 Managed by UT-Battelle for the Department of Energy Presentation_name
D
Resources
• DEER presentations – http://www1.eere.energy.gov/vehiclesandfuels/res
ources/proceedings/index.html
• CLEERS – http://cleers.org
• Society of Automotive Engineers – www.sae.org
• Health Effects Institute – 2008 Mobile Source Air Toxics report at
www.healtheffects.org
68 Managed by UT-Battelle for the Department of Energy Presentation_name
Extra slides
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X-Ray Imaging Scouting Study Approach: Measurements with commercial 3D x-ray• MDXi400 by 3D-XRAY, Ltd on
site NTRC March-May 08 • Rotating platform & X-ray fan
beam give 3D profiles • Used for defect detection in
catalytic monolith production • Examined cracks, thermal
damage, washcoat uniformity, soot & ash DPF deposition
• Responds to CLEERS poll interest in DPF monitoring
D
X
70 Managed by UT-Battelle for the Department of Energy Presentation_name
X 10-3
3
2
100 200 300 400 500 600 7001 I
- 16.7g ( 3 g/L) soot
- 17.3g ( 3.1g/L) acclimatized
800 900
distribution in-can
Significant Results (6): Confirmed measurement of DPF soot
• 6-in OD uncoated DPF (in can) • Loaded for 5 hours on
Mercedes 1.7-L engine with ULSD fuel
• Quantitative detection of axial soot loading variations thru can wall
2
1.5
1
0.5
0
71 Managed by UT-Battelle for the Department of Energy Presentation_name
Soo
t Loa
ding
(g)
0 0.2 0.4 0.6 0.8
X-ray response (a.u.)
Linear calibration curve
Significant Results (7): Also confirmed ability to image details of DPF thermal
72 Managed by UT-Battelle for the Department of Energy
damage• 150mm DPF in can
• Thermal damage (by OEM) induced near exit
• Expect to be highly useful for model/OBD validation
Presentation_name