柴油机Urea-SCR系统低温控制策略研究
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摘要
从低温反应动力学的角度出发,建立了一种可适用于低排温工况的可嵌入式模型,对选择性催化还原(SCR)系统氮氧化物(NOx)排放进行准确描述。基于上述研究,提出了一种基于模型的控制策略,并利用Matlab/Simulink软件建立后处理控制单元(DCU)标定平台,以加速SCR系统的标定过程。最后,通过世界统一(WHTC)循环进行验证。试验结果表明:采用新策略可获得高NOx转化效率,同时能降低氨气(NH3)的泄漏量。
Based on the analysis of SCR reaction kinetics at low-temperature,an embeddable SCR model was presented,which can accurately quantify transient NOxconcentration from SCR system.Following that,a model-based control strategy was presented and a dosing control unit(DCU)calibration platform was established with Matlab/Simulink to accelerate calibration process.Finally,the World Harmonized Transient Cycle tests(WHTC)were carried out.The result of the tests indicate that the control strategy presented here can achieve a better balance between high NOxreduction efficiency and low ammonia(NH3)slip.
Based on the analysis of SCR reaction kinetics at low-temperature,an embeddable SCR model was presented,which can accurately quantify transient NOxconcentration from SCR system.Following that,a model-based control strategy was presented and a dosing control unit(DCU)calibration platform was established with Matlab/Simulink to accelerate calibration process.Finally,the World Harmonized Transient Cycle tests(WHTC)were carried out.The result of the tests indicate that the control strategy presented here can achieve a better balance between high NOxreduction efficiency and low ammonia(NH3)slip.
引文
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[9]Hsieh M F,Wang J M.Development and experimental studies of a control-oriented SCR model for a two-catalyst urea-SCR system[J].Control Engineering Practice,2011,19(4):409-422.
[10]Topsoe N Y.Mechanism of the selective catalytic reduction of nitric-oxide by ammonia elucidated by in-situ online Fouriertransform infrared-spectroscopy[J].Science,1994,265(5176):1217-1219.
[11]Lietti L,Nova I,Camurri S,et al.Dynamics of the SCR-deNOxreaction by the transient-response method[J].AIChE Journal,1997,43(10):2559-2570.
[12]沈颖倩.低温SCR反应动力学研究[D].武汉:武汉理工大学,2010.
[13]Colombo M,Nova I,Tronconi E,et al.NO/NO2/N2O-NH3SCR reactions over a commercial Fe-zeolite catalyst for diesel exhaust aftertreatment:intrinsic kinetics and monolith converter modelling[J].Applied Catalysis B:Environmental,2012,12(1):106-118.
[14]Wurzenberger J C,Wanker R.Multi-scale SCR modeling,1D kinetic analysis and 3Dsystem simulation[C]//SAE 2005-01-0948,2005.
[15]冯坦.柴油机urea-SCR系统化学模型的设计与仿真研究[D].武汉:武汉理工大学,2013.
[16]Toops T J,Pihl J A,Partridge W P.Fe-zeolite functionality,durability,and deactivation mechanisms in the selective catalytic reduction(SCR)of NOx with ammonia[J].Fundamental and Applied Catalysis,2014,15(3):97-121.
[2]Johnson T.Diesel emissions in review[C]//SAE 2011-01-0304,2011.
[3]Johnson T.Vehicular emissions in review[C]//SAE 2013-01-0538,2013.
[4]Chi J N,DaCosta H F M.Modeling and control of a urea-SCR aftertreatment sytem[C]//SAE 2005-01-0966,2005.
[5]LüL,Wang L.Model-based optimization of parameters for a diesel engine SCR system[J].International Journal of Automotive Technology,2013,14(1):13-18.
[6]Willems F,Cloudt R,Eijnden E,et al.Is closed-loop SCR control required to meet future emission target[C]//SAE 2007-01-1574,2007.
[7]Ong C Y,Annaswamy A M.An adaptive proportional integral control of a urea selective catalytic reduction system based on system identification models[C]//SAE 2010-01-1174,2010.
[8]Bonfils A,Creff Y,Lepreux O,et al.Closed-loop control of a SCR system using a NOx sensor cross-sensitive to NH3[J].Journal of Process Control,2014,24(2):368-378.
[9]Hsieh M F,Wang J M.Development and experimental studies of a control-oriented SCR model for a two-catalyst urea-SCR system[J].Control Engineering Practice,2011,19(4):409-422.
[10]Topsoe N Y.Mechanism of the selective catalytic reduction of nitric-oxide by ammonia elucidated by in-situ online Fouriertransform infrared-spectroscopy[J].Science,1994,265(5176):1217-1219.
[11]Lietti L,Nova I,Camurri S,et al.Dynamics of the SCR-deNOxreaction by the transient-response method[J].AIChE Journal,1997,43(10):2559-2570.
[12]沈颖倩.低温SCR反应动力学研究[D].武汉:武汉理工大学,2010.
[13]Colombo M,Nova I,Tronconi E,et al.NO/NO2/N2O-NH3SCR reactions over a commercial Fe-zeolite catalyst for diesel exhaust aftertreatment:intrinsic kinetics and monolith converter modelling[J].Applied Catalysis B:Environmental,2012,12(1):106-118.
[14]Wurzenberger J C,Wanker R.Multi-scale SCR modeling,1D kinetic analysis and 3Dsystem simulation[C]//SAE 2005-01-0948,2005.
[15]冯坦.柴油机urea-SCR系统化学模型的设计与仿真研究[D].武汉:武汉理工大学,2013.
[16]Toops T J,Pihl J A,Partridge W P.Fe-zeolite functionality,durability,and deactivation mechanisms in the selective catalytic reduction(SCR)of NOx with ammonia[J].Fundamental and Applied Catalysis,2014,15(3):97-121.