李顶根，朱红雨，成晓北

华中科技大学 能源与动力工程学院

摘要：为了实现重型柴油机NO_x排放满足国Ⅴ排放标准，获得更好的SCR控制效果，利用Matlab/Simulink建立了SCR（Selective Catalytic Reduction）数学模型和控制模型。提出了基于模型的前馈加PID反馈修正的闭环尿素喷射控制策略，并对模型和控制策略进行了仿真测试和实验验证，采用扩展卡尔曼滤波算法消除NH₃对NO_x传感器造成的交叉敏感误差。结果表明：模型误差在5%以内能够满足建模和控制要求；ESC和ETC测试循环SCR平均转化效率在80%以上，瞬态转化效率最高可达96%；控制器的动态响应性较好。

关键词：选择性催化还原 闭环控制 转化效率 扩展卡尔曼滤波

Abstract: With the purpose to ensure that the NOx of a HV diesel engine meet V emission standards, and  the SCR control effect of the heavy-duty diesel engine is good, this paper establishes the model of SCR (selective catalytic reduction) and the controller basing on Matlab/Simulink software, and proposed the closed-loop control strategy of urea-injection with the help of model feedforward and PID feedback corrections, and did validation via simulation and experiments. Furthermore, the paper uses Extended Kalman filter algorithm to eliminate the crossed sensitivity between with NOx sensor and NH₃ during the experiments. The results show that the error of model controlled within 5% will satisfy the demands of modeling and controlling. The average conversion efficiency is above 80% during the test of ESC and ETC, and the transient efficiency is nearly up to 96%.  The dynamic response performance of control strategy is also very good.

Key words: SCR; Closed-loop Control; Conversion Efficiency; Extended Kalman Filter