In this paper, we investigate the nonlinear observer designs to estimate the ammonia coverage ratio in the diesel engine selective catalytic reduction (SCR) systems. The ammonia coverage ratio is an important variable due to its critical role in the SCR NOx conversion and the ammonia slip. However, the ammonia coverage ratio cannot be directly measured by onboard sensors. Therefore, it is necessary to develop effective observers to estimate the ammonia coverage ratio online. Based on a three-state SCR model, we develop two nonlinear observers. The first one only employs the dynamics of the ammonia concentration. The structure and the algorithm are simple. But it is sensitive to the measurement noises and the uncertainties in the system parameters. The second one is a discrete-time smooth variable structure estimator which is robust to the measurement noises, the approximation error, and the system uncertainties. Both estimators are implemented on a full-vehicle simulation of the FTP75 test cycle. The simulation results have verified the theoretical analysis.

References

References
1.
Hsieh
,
M.-F.
, and
Wang
,
J.
,
2011
, “
NO and NO2 Concentration Modeling and Observer-Based Estimation Across a Diesel Engine Aftertreatment System
,”
ASME J. Dyn. Sys., Meas., Control
,
133
(
4
), p.
041005
.10.1115/1.4003380
2.
Koebel
,
M.
,
Elsener
,
M.
, and
Kleemann
,
M.
,
2000
, “
Urea-SCR: A Promising Technique to Reduce NOx Emissions From Automotive Diesel Engines
,”
Catal. Today
,
59
(
3–4
), pp.
335
345
.10.1016/S0920-5861(00)00299-6
3.
Hsieh
,
M.-F.
, and
Wang
,
J.
,
2012
, “
Adaptive and Efficient Ammonia Storage Distribution Control for a Two-Catalyst Selective Catalytic Reduction System
,”
ASME J. Dyn. Sys., Meas., Control
,
134
(
1
), p.
011012
.10.1115/1.4005372
4.
Perry
,
A.
, and
Siebers
,
D. L.
,
1986
, “
Rapid Reduction of Nitrogen Oxides in Exhaust Gas Streams
,”
Nature (London)
,
324
, pp.
657
658
.10.1038/324657a0
5.
Hsieh
,
M.-F.
, and
Wang
,
J.
,
2011
, “
A Two-Cell Backstepping Based Control Strategy for Diesel Engine Selective Catalytic Reduction Systems
,”
IEEE Trans. Control Syst. Technol.
,
19
(
6
), pp.
1504
1515
.10.1109/TCST.2010.2098477
6.
Johnson
,
T.
,
2008
, “
Diesel Engine Emissions and Their Control an Overview
,”
Platinum Met. Rev.
,
52
(
1
), pp.
23
37
.10.1595/147106708X248750
7.
Johnson
,
T. V.
,
2008
, “
Diesel Emission Control in Review
,” 2008 SAE World Congress, SAE Technical Paper No. 2008–01–0069.
8.
Hsieh
,
M.-F.
, and
Wang
,
J.
,
2010
, “
Observer-Based Estimation of Selective Catalytic Reduction Catalyst Ammonia Storage
,”
Proc. Inst. Mech. Eng., Part D (J. Automob. Eng.)
,
224
(
9
), pp.
1199
1211
.10.1243/09544070JAUTO1482
9.
Zhang
,
H.
,
Saadat Mehr
,
A.
, and
Shi
,
Y.
,
2010
, “
Improved Robust Energy-to-Peak Filtering for Uncertain Linear Systems
,”
Signal Process.
,
90
(
9
), pp.
2667
2675
.10.1016/j.sigpro.2010.03.011
10.
Zhang
,
H.
,
Shi
,
Y.
, and
Saadat Mehr
,
A.
,
2012
, “
Robust Equalisation for Inter Symbol Interference Communication Channels
,”
IET Signal Process.
,
6
(
2
), pp.
73
78
.10.1049/iet-spr.2010.0367
11.
Zhang
,
H.
,
Shi
,
Y.
, and
Saadat Mehr
,
A.
,
2012
, “
On H Filtering for Discrete-Time Takagi-Sugeno Fuzzy Systems
,”
IEEE Trans. Fuzzy Syst.
,
20
(
2
), pp.
396
401
.10.1109/TFUZZ.2011.2175933
12.
Chi
,
J. N.
, and
DaCosta
,
H. F. M.
,
2005
, “
Modeling and Control of a Urea-SCR Aftertreatment System
,” 2005 SAE World Congress, SAE Technical Paper No. 2005-01-0966.
13.
Schar
,
C. M.
,
Onder
,
C. H.
, and
Geering
,
H. P.
,
2006
, “
Control of an SCR Catalyst Converter System for a Mobile Heavy-Duty Application
,”
IEEE Trans. Control Syst. Technol.
,
14
(
4
), pp.
641
652
.10.1109/TCST.2006.876634
14.
Willems
,
F.
,
Cloudt
,
R.
,
van den Eijnden
,
E.
,
van Genderen
,
M.
,
Verbeek
,
R.
,
de Jager
,
B.
,
Boomsma
,
W.
, and
van den Heuvel
,
I.
,
2007
, “
Is Closed-Loop SCR Control Required to Meet Future Emission Targets?
,” 2007 SAE World Congress, SAE Technical Paper No. 2007-01-1574.
15.
Wang
,
D. Y.
,
Yao
,
S.
,
Shost
,
M.
,
Yoo
,
J.-H.
,
Cabush
,
D.
, and
Racine
,
D.
,
2008
, “
Ammonia Sensor for Closed-Loop SCR Control
,” 2008 SAE World Congress, SAE Technical Paper No. 2008-01-0919.
16.
Willems
,
F.
, and
Cloudt
,
R.
,
2011
, “
Experimental Demonstration of a New Model-Based SCR Control Strategy for Cleaner Heavy-Duty Diesel Engines
,”
IEEE Trans. Control Syst. Technol.
,
19
(
5
), pp.
1305
1313
.10.1109/TCST.2010.2057510
17.
Yim
,
S. D.
,
Kim
,
S. J.
,
Baik
,
J. H.
, and
Nam
, I.-S
.
,
2004
, “
Decomposition of Urea Into NH3 for the SCR Process
,”
Ind. Eng. Chem. Res.
,
43
(
16
), pp.
4856
4863
.10.1021/ie034052j
18.
Hsieh
,
M.-F.
, and
Wang
,
J.
,
2011
, “
Development and Experimental Studies of a Control-Oriented SCR Model for a Two-Catalyst Urea-SCR System
,”
Control Eng. Pract.
,
19
(
4
), pp.
409
422
.10.1016/j.conengprac.2011.01.004
19.
Tronconi
,
E.
,
Lieti
,
L.
,
Forzatti
,
P.
, and
Malloggi
,
S.
,
1996
, “
Experimental and Theoretical Investigation of the Dynamics of the SCR-DeNOx Reaction
,”
Chem. Eng. Sci.
,
51
(
11
), pp.
2965
2970
.10.1016/0009-2509(96)00182-0
20.
Meisami-Azad
,
M.
,
Mohammadpoura
,
J.
,
Grigoriadisa
,
K. M.
,
Haroldb
,
M. P.
, and
Franchek
,
M. A.
,
2012
, “
LPV Gain-Scheduled Control of SCR Aftertreatment Systems
,”
Int. J. Control
,
85
(
1
), pp.
114
133
.10.1080/00207179.2011.639090
21.
Arnett
,
M.
,
Bayer
,
K.
,
Coburn
,
C.
,
Guezzenec
,
Y.
,
Koprubasi
,
K. S. M.-M.
,
Sevel
,
K.
,
Shakiba-Herfeh
,
M.
, and
Rizzoni
,
G.
,
2008
, “
Cleaner Diesel Using Model-Based Design and Advanced Aftertreatment in a Student Competition Vehicle
,” 2008 SAE Congress, SAE Technical Paper No. 2008-01-0868.
22.
Pisu
,
P.
,
Canova
,
M.
, and
Soliman
,
A.
,
2008
, “
Model-Based Fault Diagnosis of a NOx Aftertreatment System
,” Proceedings of the 17th IFAC World Congress, pp.
7072
7078
.
23.
Wang
,
R.
, and
Wang
,
J.
,
2012
, “
Fault-Tolerant Control for Electric Ground Vehicles With Independently-Actuated in-Wheel Motors
,”
ASME J. Dyn. Sys., Meas., Control
,
134
(
2
), p.
021014
.10.1115/1.4005050
24.
Wang
,
S.
,
2007
, “
Integrated Control and Estimation Based on Sliding Mode Control Applied to Electrohydraulic Actuator
,” Ph.D. thesis, University of Saskatchewan, Canada.
25.
Zhang
,
H.
,
Shi
,
Y.
, and
Saadat Mehr
,
A.
,
2010
, “
Robust Energy-to-Peak Filtering for Networked Systems With Time-Varying Delays and Randomly Missing Data
,”
IET Control Theory Appl.
,
4
(
12
), pp.
2921
2936
.10.1049/iet-cta.2009.0243
26.
Zhang
,
H.
,
Shi
,
Y.
, and
Saadat Mehr
,
A.
,
2011
, “
Robust Weighted H Filtering for Networked Systems With Intermitted Measurements of Multiple Sensors
,”
Int. J. Adapt. Control Signal Process.
,
25
(
4
), pp.
313
330
.10.1002/acs.1200
27.
Zhang
,
H.
,
Shi
,
Y.
,
Saadat Mehr
,
A.
, and
Huang
,
H.
,
2011
, “
Robust Energy-to-Peak FIR Equalization for Time-Varying Communication Channels With Intermittent Observations
,”
Signal Process.
,
91
(
7
), pp.
1651
1658
.10.1016/j.sigpro.2011.01.011
28.
Zhang
,
H.
,
Shi
,
Y.
, and
Saadat Mehr
,
A.
,
2011
, “
Robust Static Output Feedback Control and Remote PID Design for Networked Motor Systems
,”
IEEE Trans. Ind. Electron.
,
58
(
12
), pp.
5396
5405
.10.1109/TIE.2011.2107720
29.
Zhang
,
H.
,
Shi
,
Y.
, and
Liu
,
M. X.
,
2013
, “H
Step Tracking Control for Networked Discrete-Time Nonlinear Systems With Integral and Predictive Actions
,”
IEEE Trans. Ind. Inf.
,
9
(
1
), pp.
337
345
.10.1109/TII.2012.2225434
30.
Zhang
,
H.
,
Shi
,
Y.
, and
Saadat Mehr
,
A.
,
2012
, “
Robust H PID Control for Multivariable Networked Control Systems With Disturbance/Noise Attenuation
,”
Int. J. Robust Nonlinear Control
,
22
(
2
), pp.
183
204
.10.1002/rnc.1688
31.
Zhang
,
H.
, and
Shi
,
Y.
,
2012
, “
Observer-Based H Feedback Control for Arbitrarily Time-Varying Discrete-Time Systems With Intermittent Measurements and Input Constraints
,”
ASME J. Dyn. Sys., Meas., Control
,
134
(
6
), p.
061008
.10.1115/1.4006070
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