Adaptive Model Predictive Control of an SCR Catalytic Converter System for Automotive Applications

Selective catalytic reduction (SCR) is coming into worldwide use for diesel engine emissions reduction of on- and off-highway vehicles. These applications are characterized by broad operating range as well as rapid and unpredictable changes in operating condition. Significant nonlinearity, input, and output constraints, and stringent performance requirements have led to the proposal of many different advanced control strategies. This article introduces a model predictive feedback controller based on a nonlinear, reduced order model. Computational effort is significantly reduced through successive linearization, analytical solutions, and a varying terminal cost function. A gradient-based parameter adaptation law is employed to achieve consistent performance. The controller is demonstrated in simulation for an on-highway heavy-duty diesel engine over two widely different emissions test cycles and for 24 different plants. Comparisons with baseline control designs reveal the attractive features as well as the limitations of this approach.

[1]  Louise Olsson,et al.  A kinetic model for ammonia selective catalytic reduction over Cu-ZSM-5 , 2008 .

[2]  Eduardo F. Camacho,et al.  Model predictive control in the process industry , 1995 .

[3]  S. Joe Qin,et al.  A survey of industrial model predictive control technology , 2003 .

[4]  Timothy V. Johnson,et al.  Review of diesel emissions and control , 2009 .

[5]  Anuradha M. Annaswamy,et al.  An Adaptive Proportional Integral Control of a Urea Selective Catalytic Reduction System based on System Identification Models , 2010 .

[6]  P. O'Connor,et al.  Practical Reliability Engineering , 1981 .

[7]  George Zhu,et al.  Model-based Closed-loop Control of Urea SCR Exhaust Aftertreatment System for Diesel Engine , 2002 .

[8]  Michiel J. Van Nieuwstadt,et al.  Model Based Analysis and Control Design of a Urea-SCR deNOx Aftertreatment System , 2006 .

[9]  Eduardo Fernandez-Camacho,et al.  Model Predictive Control in the Process Industry , 1995 .

[10]  Christopher H. Onder,et al.  Control of an SCR catalytic converter system for a mobile heavy-duty application , 2006, IEEE Transactions on Control Systems Technology.

[11]  D. Q. Mayne,et al.  Suboptimal model predictive control (feasibility implies stability) , 1999, IEEE Trans. Autom. Control..

[12]  Pio Forzatti,et al.  Adequacy of lumped parameter models for SCR reactors with monolith structure , 1992 .

[13]  Zoltan K. Nagy,et al.  Model Based Control: Case Studies in Process Engineering , 2006 .

[14]  Andrew G. Alleyne,et al.  A switched, controls-oriented SCR catalyst model using on-line eigenvalue estimation , 2009 .

[15]  Fpt Frank Willems,et al.  Is Closed-Loop SCR Control Required to Meet Future Emission Targets? , 2007 .

[16]  Andrew G. Alleyne,et al.  Model predictive control: A unified approach for urea-based SCR systems , 2010 .

[17]  David Q. Mayne,et al.  Constrained model predictive control: Stability and optimality , 2000, Autom..

[18]  Frank Willems,et al.  Ammonia sensor for closed-loop SCR control , 2008 .

[19]  B. Bequette.  Nonlinear control of chemical processes: a review , 1991 .

[20]  Gordon G. Parker,et al.  Model-Based Estimation and Control System Development in a Urea-SCR Aftertreatment System , 2008 .

[21]  Thomas L. McKinley,et al.  Adaptive Model Predictive Control of Diesel Engine Selective Catalytic Reduction (SCR) Systems. , 2009 .

[22]  J. N. Chi,et al.  Modeling and Control of a Urea-SCR Aftertreatment System , 2005 .