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Dynamic flow control strategies of vehicle SCR Urea Dosing System
Chinese Journal of Mechanical Engineering volume 28, pages 276–284 (2015)
Abstract
Selective Catalyst Reduction(SCR) Urea Dosing System(UDS) directly affects the system accuracy and the dynamic response performance of a vehicle. However, the UDS dynamic response is hard to keep up with the changes of the engine’s operating conditions. That will lead to low NO X conversion efficiency or NH3 slip. In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions, an advanced control strategy based on an air-assisted volumetric UDS is presented. It covers the methods of flow compensation and switching working conditions. The strategy is authenticated on an UDS and tested in different dynamic conditions. The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS. The inject deviation range is improved from being between −8% and 10% to −4% and 2% and became more stable than before, and the dynamic response time was shortened from 200 ms to 150 ms. The ETC cycle result shows that after using the new strategy the NH3 emission is reduced by 60%, and the NO X emission remains almost unchanged. The trade-off between NO X conversion efficiency and NH3 slip is mitigated. The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine’s operating conditions quickly.
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Supported by National Hi-tech Research and Development Program of China(863 Program, Grant No. 2012AA111708)
LIN Wei, born in 1987, is currently a PhD candidate at Beijing Institute of Technology, China. He received his master degree from Beijing Institute of Technology, China, in 2012. His research interests include SCR system control.
ZHANG Youtong, born in 1965, is currently a professor and a doctoral instructor at Beijing Institute of Technology, China. He received his PhD degree from Beijing Institute of Technology, China, in 1995. His research interests include vehicle power system control.
ASIF Malik, born 1985, is a master candidate at Beijing Institute of Technology, China. He received his bachelor of engineering (BE) degree from National University of Sciences and Technology, Pakistan, in 2006. Since then he has been serving as a manager in an armored vehicles manufacturing organization of his country. His research is aimed to engine performance analysis especially the exhaust emission control with SCR.
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Lin, W., Zhang, Y. & Asif, M. Dynamic flow control strategies of vehicle SCR Urea Dosing System. Chin. J. Mech. Eng. 28, 276–284 (2015). https://doi.org/10.3901/CJME.2014.1201.174
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DOI: https://doi.org/10.3901/CJME.2014.1201.174