Lean NOx trap (LNT) catalytic aftertreatment devices are one potential option for the reduction of oxides of nitrogen (NOx) in the exhaust of compression ignition engines. They work through a controlled modulation between a storage phase that captures NOx over an alkali earth metal and a regeneration phase that reduces the stored nitrates on the surface using a rich pulse of injected fuel or via stoichiometric engine operation. This rich phase has an associated fuel penalty while being relatively difficult to control through temperature and chemical species. In order to improve system efficiency, a number of researchers have proposed dual leg LNT systems using two LNTs, one of which is always storing while the other is undergoing regeneration. The majority of the exhaust flows through the storage LNT while only a small fraction (low space velocity) advects across the regeneration LNT. This increases the regeneration residence time, improving effectiveness and decreasing the amount of fuel used. From an LNT simulation standpoint, most researchers utilize the classical one-dimensional (1D) aftertreatment model constructed from the Euler equations of motion that neglect axial conduction and diffusion. This paper explores the applicability of this model under low flow situations prevalent in a dual leg LNT system through a carbon monoxide light-off experiment. The authors chose this type of experiment in order to focus purely on fluid mechanics and not the choice of LNT reaction mechanism. The results suggest that a Navier–Stokes (N–S) version of the 1D aftertreatment model is preferred for the regeneration leg of a dual LNT system. Moreover, the authors provide the solution of such a model within this paper.

References

References
1.
UCSUSA,
2008
,
Diesel Passenger Vehicles and the Environment
, Union of Concerned Scientists, Cambridge, MA, available at: http://www.ucsusa.org/assets/documents/clean_vehicles/diesel-123.pdf.
2.
Koltsakis
, G.
and
Stamatelos
, A.
, 1997, “
Catalytic Automotive Exhaust Aftertreatment
,”
Progr. Energy Comb. Sci.
,
23
(1), pp.
1
39
.10.1016/S0360-1285(97)00003-8
3.
Chorkendorff
,
I.
, and
Niemantsverdriet
,
J. W.
,
2007
,
Concepts of Modern Catalysis and Kinetics
,
Wiley-VCH
,
Berlin
.
4.
Bosch
,
H.
, and
Janssen
,
F. J.
,
1988
, “
Formation and Control of Nitrogen Oxides
,”
Catal. Today
,
2
(
4
), pp.
369
379
.10.1016/0920-5861(88)80001-4
5.
Depcik
,
C.
,
Assanis
,
D.
, and
Bevan
,
K.
,
2008
, “
A One-Dimensional Lean NOx Trap Model With a Global Kinetic Mechanism That Includes NH3 and N2O
,”
Int. J. Engine Res.
,
9
(
1
), pp.
57
78
.10.1243/14680874JER01807
6.
Farrauto
,
R.
,
2008
, “
Automotive Emission Control: Past, Present and Future
,”
Philadelphia Catalysis Society Spring Symposium, Newark, DE, May 22, North American Catalysis Society
, Orefield, PA.
7.
Schenk
,
C.
,
McDonald
,
J.
, and
Olson
,
B.
,
2001
, “
High-Efficiency NOx and PM Exhaust Emission Control for Heavy-Duty On-Highway Diesel Engines
,”
SAE
Technical Paper No. 2001-01-1351.10.4271/2001-01-1351
8.
Nam
,
G.
,
Park
,
W. J.
,
Lee
,
J.
, and
Yeo
,
G.
,
2007
, “
The Effect of an External Fuel Injection on the Control of LNT System: The Diesel NOx Reductive System
,”
SAE
Technical Paper No. 2007-01-1242.10.4271/2007-01-1242
9.
Webb
,
C.
,
Weber
,
P.
, and
Thornton
,
M.
,
2004
, “
Achieving Tier 2 Bin 5 Emission Levels With a Medium Duty Diesel Pick-Up and a NOX Adsorber, Diesel Particulate Filter Emissions System-Exhaust Gas Temperature Management
,”
SAE
Technical Paper No. 2004-01-0584.10.4271/2004-01-0584
10.
Whitacre
,
S.
,
Adelman
,
B.
, and
May-Ricardo
,
M.
,
2004
, “
Systems Approach to Meeting EPA 2010 Heavy-Duty Emission Standards Using a NOx Adsorber Catalyst and Diesel Particle Filter on a 15L Engine
,”
SAE
Technical Paper No. 2004-01-0587.10.4271/2004-01-0587
11.
Tsumagari
,
I.
,
Hirabayashi
,
H.
,
Takenaka
,
Y.
,
Hosoya
,
M.
, and
Shimoda
,
M.
,
2006
, “
Study of 2-Leg NOx Storage-Reduction Catalyst System for HD Diesel Engine
,”
SAE
Technical Paper No. 2006-01-0211.10.4271/2006-01-0211
12.
Johnson
,
T.
,
2008
, “
Diesel Engine. Emissions and Their Control
,”
Platinum Met. Rev.
,
52
(
1
), pp.
23
37
.10.1595/147106708X248750
13.
Crane
,
S.
,
Iverson
,
R. J.
,
Goldschmidt
,
S.
,
Greathouse
,
M. W.
, and
Khadiya
,
N.
,
2005
, “
Recent Advances in Utilizing the Plasma Fuel Reformer for Nox Trap Regeneration
,”
SAE
Technical Paper No. 2005-01-3547.10.4271/2005-01-3547
14.
Laroo
,
C.A.
, and
Schenk
,
C. R.
,
2007
, “
NOx Adsorber Aging on a Heavy-Duty On-Highway Diesel Engine: Part Two
,”
SAE
Technical Paper No. 2007-01-0468.10.4271/2007-01-0468
15.
Kong
,
Y.
,
Huffmeyer
,
C. R.
,
Johnson
,
R. J.
,
Taylor
,
W.
,
Crawley
,
W.
, and
Hayworth
,
G.
,
2004
, “
Applications of an Active Diesel Particulate Filter Regeneration System
,”
SAE
Technical Paper No. 2004-01-2660.10.4271/2004-01-2660
16.
Johnson
,
T. V.
,
2007
, “
Diesel Emission Control in Review
,”
SAE
Technical Paper No. 2007-01-0233.10.4271/2007-01-0233
17.
Salasc
,
S.
,
Barrieu
,
E.
, and
Leroy
,
V.
,
2005
, “
Impact of Manifold Design on Flow Distribution of a Close-Coupled Catalytic Converter
,”
SAE
Technical Paper No. 2005-01-1626.10.4271/2005-01-1626
18.
Depcik
,
C.
, and
Assanis
,
D.
,
2005
, “
One-Dimensional Automotive Catalyst Modeling
,”
Prog. Energy Combust. Sci.
,
31
, pp.
308
369
.10.1016/j.pecs.2005.08.001
19.
Depcik
,
C.
,
2008
, “
Catalyst Modeling: ME 790
,” Doctoral dissertation,
University of Kansas
,
Lawrence
, KS.
20.
Depcik
,
C.
,
Loya
,
S.
, and
Srinivasan
,
A.
,
2009
, “
Adaptive Carbon Monoxide Kinetics for Exhaust Aftertreatment Modeling
,”
ASME International Mechanical Engineering Congress and Exposition (IMECE)
,
Lake Buena Vista, FL
, November 13-19,
ASME
Paper No. IMECE2009-11173, pp.
297
307
.10.1115/IMECE2009-11173
21.
Chen
,
D.
,
Bissett
,
E.
,
Oh
,
S.
, and
Van Ostrom
,
D.
,
1988
, “
A Three-Dimensional Model for the Analysis of Transient Thermal and Conversion Characteristics of Monolithic Catalytic Converters
,”
SAE
Technical Paper No. 880282.10.4271/880282
22.
Edelbauer
,
W.
,
Kutschi
,
S.
, and
Wurzenberger
,
J.
,
2012
, “
xD+1D Catalyst Simulation —A Numerical Study on the Impact of Pore Diffusion
,”
SAE
Technical Paper No. 2012-01-1296.10.4271/2012-01-1296
23.
Loya
,
S.
,
2011
, “
Dynamic Incompressible Navier–Stokes Model of Catalytic Converter in 1-D Including Fundamental Oxidation Reaction Rate Expressions
,”
Mechanical Engineering
,
University of Kansas
,
Lawrence
, KS.
24.
Anderson
,
J. J.
,
1995
,
Computational Fluid Dynamics: The Basic With Applications
,
McGraw-Hill
,
Singapore
.
25.
Fox
,
R.
,
McDonald
,
A.
, and
Pritchard
,
P.
,
2003
,
Introduction to Fluid Mechanics
,
6th ed.
,
John Wiley and Sons
,
Hoboken
, NJ.
26.
White
,
F.
,
2003
,
Fluid Mechanics
,
5th ed.
,
McGraw-Hill
,
New York
.
27.
Panton
,
R.
,
2005
,
Incompressible Flow
,
3rd ed.
,
John Wiley and Sons
,
Hoboken
, NJ.
28.
Almgren
,
A. S.
,
Bell
,
J. B.
,
Rendleman
,
C. A.
, and
Zingale
,
M.
,
2006
, “
Low Mach Number Modeling of Type Ia Supernovae. I. Hydrodynamics
,”
Astrophys. J.
,
637
, pp.
922
936
.10.1086/498426
29.
Depcik
,
C.
, and
Loya
,
S.
,
2012
, “
Dynamically Incompressible Flow
,” Advanced Methods for Practical Applications in Fluid Mechanics, S. Jones, ed., InTech, New York, Chap. 4, available at: http://www.intechopen.com/books/advanced-methods-for-practical-applications-in-fluidmechanics/dynamically-incompressible-flow
30.
Morgon
,
C. R.
,
Carlson
,
D. W.
, and
Voltz
,
S. E.
,
1973
, “
Thermal Response and Emission Breakthrough of Platinum Monolithic Catalytic Converters
,”
SAE
Technical Paper No. 730569.10.4271/730569
31.
Depik
,
C.
,
2008
, “
Catalyst Modeling: Aftertreatment Devices
,”
Catalyst Modeling
,
University of Kansas
,
Lawrence
, KS.
32.
Knudsen
,
J.
, and
Katz
,
D.
,
1958
,
Fluid Dynamics and Heat Transfer
,
McGraw-Hill
,
New York
, p.
576
.
33.
Kuo
,
J. C.
,
Morgon
,
C. R.
, and
Lassen
,
H. G.
,
1989
, “
Mathematical Modeling of CO and HC Catalytic Converter Systems
,”
SAE
Technical Paper No. 710289.10.4271/710289
34.
Fleming
,
D. P.
, and
Sparrow
,
E. M.
,
1969
, “
Flow in the Hydrodynamics Entrance Region of Ducts of Arbitrary Cross Section
,”
ASME J. Heat Transfer
,
91
, pp.
345
354
.10.1115/1.3580173
35.
Manohar
,
R.
,
1969
, “
Analysis of Laminar Flow Heat Transfer in the Entrance Region of Circular Tubes
,”
Int. J. Heat Mass Transfer
,
12
(
1
), pp.
15
22
.10.1016/0017-9310(69)90074-X
36.
Incorpera
,
F.
, and
De Witt
,
D.
,
1990
,
Fundamentals of Heat and Mass Transfer
,
3rd ed.
,
John Wiley and Sons
,
New York
.
37.
Kee
,
R.
,
Coltrin
,
M.
, and
Glarborg
,
P.
,
2003
,
Chemically Reacting Flow: Theory and Practice
,
John Wiley and Sons
,
Hoboken
, NJ.
38.
Cussler
,
E. L.
,
1997
,
Diffusion: Mass Transfer in Fluid Systems
,
2nd ed.
,
Cambridge University Press
,
Cambridge
, UK.
39.
Kuo
,
K.
,
2005
,
Principles of Combustion
,
2nd ed.
,
John Wiley and Sons
,
Hoboken
, NJ.
40.
Koltsakis
,
G. C.
,
Konstantinidis
,
P. A.
, and
Stamatelos
,
A. M.
,
1997
, “
Development and Application Range of Mathematical Models for 3-Way Catalytic Converters
,”
Appl. Catal. B
,
12
(
2–3
), pp.
161
191
.10.1016/S0926-3373(96)00073-2
41.
Arnby
,
K.
,
Assiks
,
J.
,
Carlsson
,
P.-A.
,
Palmqvist
,
A.
, and
Skoglundh
,
M.
,
2005
, “
The Effect of Platinum Distribution in Monolithic Catalysts on the Oxidation of CO and Hydrocarbons
,”
J. Catal.
,
233
, pp.
176
185
.10.1016/j.jcat.2005.04.031
42.
Arnby
,
K.
,
Törncrona
,
A.
,
Andersson
,
B.
, and
Skoglundh
,
M.
,
2004
, “
Investigation of Pt/γ-Al2O3 Catalysts With Locally High Pt Concentrations for Oxidation of CO at Low Temperatures
,”
J. Catal.
,
221
(
1
), pp.
252
261
.10.1016/j.jcat.2003.08.017
43.
Salomons
,
S.
,
Hayes
,
R. E.
,
Votsmeier
,
M.
,
Drochner
,
A.
,
Vogel
,
H.
,
Malmberg
,
S.
, and
Gieshoff
,
J.
,
2007
, “
On the Use of Mechanistic CO Oxidation Models With a Platinum Monolith Catalyst
,”
Appl. Catal. B
,
70
(
1–4
), pp.
305
313
.10.1016/j.apcatb.2006.01.022
44.
Petersson
,
M.
,
Jonsson
,
D.
,
Persson
,
H.
,
Cruise
,
N.
, and
Andersson
,
B.
,
2006
, “
Ozone Promoted Carbon Monoxide Oxidation on Platinum/γ-Alumina Catalyst
,”
J. Catal.
,
238
, pp.
321
329
.10.1016/j.jcat.2006.01.002
45.
Arnby
,
K.
,
Torncrona
,
A.
,
Andersson
,
B.
, and
Skoglundh
,
M.
,
2004
, “
Investigations of Pt/Alumina Catalysts With Locally High Platinum Concentration for Oxidation of CO at Low Temperature
,”
J. Catal.
,
221
, pp.
252
261
.10.1016/j.jcat.2003.08.017
46.
Stuwe
,
K.
,
2007
,
Geodynamics of the Lithosphere: An Introduction
,
Springer
,
New York
, p.
493
.
47.
Albright
,
L.
, and
Albright
,
L. F.
,
2008
,
Albright's Chemical Engineering Handbook
,
L.
Albright
, ed.,
CRC
,
Boca Raton
, FL.
48.
Nielaba
,
P.
,
Mareschal
,
M.
, and
Ciccotti
,
G.
,
2002
,
Bridging Time Scales: Molecular Simulations for the Next Decade
, Vol.
605
,
P.
Nielaba
,
M.
Mareschal
, and
G.
Ciccotti
, eds.,
Springer
,
New York
, p.
500
.
You do not currently have access to this content.