Model-based control system design in a urea-SCR aftertreatment system based on NH3 sensor feedback
- 678 Downloads
This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment system based on NH3 sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with design based on a sliding mode control framework. The control system based on NH3 sensor feedback is analyzed via simulation by comparing it to a control system developed based on NOx sensor feedback. Simulation results show that the NH3 sensor-based strategy performs very similarly in comparison to a NOx sensor-based strategy. The control system performance metrics for NOx index, urea index, urea usage, and NH3 slip suggest that the NOx sensor can be a potential alternative to a NOx sensor for urea-SCR control applications.
Key WordsUrea-SCR catalyst Model-based estimation Observer Control system design NH3 sensor Sliding mode control
- Czerwsinki, J., Peterman, J., Comte, P., Lemaire, J. and Mayer, A. (2007). Diesel NO/NO2/NOx emissions — New experiences and challenges. SAE Paper No. 2007-01-0321.Google Scholar
- Devarakonda, M. N., (2008c). Dynamic Modeling, Simulation and Development of Model Based Control Strategies in a Urea-SCR Aftertreatment System for Heavy Duty Diesel Engines. Ph.D. Dissertation. Michigan Tech University.Google Scholar
- Devarakonda, M., Parker, G., Johnson, J. H. and Strots, V. (2008d). Simulation based control system analysis of a urea SCR aftertreatment system based on NH3 sensor feedback. Cross-cut Lean Exhaust Emissions Reduction Simullation (CLEERS) Workshop. www.cleers.org.
- Devarakonda, M., Parker, G., Johnson, J. H., Strots, V. and Santhanam, S. (2008a). Adequacy of reduced order models for model based control in a urea-SCR aftertreatment system. SAE Paper No. 2008-01-0617 (Also accepted as a special publication in SP-2155).Google Scholar
- Devarakonda, M., Parker, G., Johnson, J. H., Strots, V. and Santhanam, S. (2008b). Model based estimation and control strategy development for urea-SCR aftertreatment system. Int. J. Fuels and Lubricants 1,1, 646–661.Google Scholar
- Tronconi, E., Nova, I., Grossale, A. and Ciardelli, C. (2007). Catalytic mechanism, detailed kinetics and converter model for NH3-SCR of NOx emissions from vehicles. Cross-cut Lean Exhaust Emissions Reduction Simulation (CLEERS) Workshop. www.cleers.org.
- Upadhyay, D. and Van Nieuwstadt (2002). Control design of an automotive urea SCR catalyst. ASME Int. Mechanical Engineering Cong. and Exposition, IMECE2002-32103.Google Scholar
- Upadhyay, D. and Van Nieuwstadt, M. (2006). Model based analysis and control design of a Urea-SCR DeNOx aftertreatment system. ASME J. Dynamic Systems, Measurement and Control, 128.Google Scholar
- Wang, D., Tao, S., Cabush, D. and Racine, D. (2007). Ammonia sensor for SCR NOx reduction. Diesel Engines Emissions Reduction (DEER) Conf. Google Scholar