柴油机Urea-SCR系统尿素喷射控制策略研究  

Study on Urea Dosing Control Strategy for Urea-SCR System in Diesel Engine

作　　者：王天田[1] 颜伏伍[1] 刘传宝[1] 胡杰[1] 

机构地区：[1]武汉理工大学现代汽车零部件技术湖北省重点实验室,武汉430070

出　　处：《内燃机工程》2015年第4期1-7,共7页Chinese Internal Combustion Engine Engineering

基　　金：国家支撑计划项目(2011BAG06B04);国际合作项目(2012DFA11180);新教师基金项目(2011-IV-129)

摘　　要：基于某重型柴油机上匹配的选择性催化还原(selective catalytic reduction,SCR)系统,开发了尿素喷射控制策略,包括带有氮氧化物(NOx)体积浓度自校正功能的原机排放预估模型、尿素基本供给量前馈控制算法、基于NH3覆盖度预测模型的反馈补偿算法、催化器载体瞬态温变修正策略和瞬态工况氨(NH3)泄漏控制策略。研究结果表明:新策略提高了控制系统瞬态工况的鲁棒性,降低了老化或工况快速变化时NH3泄漏的概率,使NOx转化效率控制在60%以上,NH3泄漏平均值控制在25×10-6以下。开发的SCR系统匹配到目标发动机后经欧洲稳态测试循环(European steady stage cycle,ESC)和欧洲瞬态循环(European transient cycle,ETC)排放试验验证达到国-Ⅳ标准。Based on a heavy diesel engine equipped with selective catalytic reduction（SCR）system,an urea dosing control strategy was developed,including the original engine emission prediction model with NOx concentration self-tuning model algorithmic control,the feed-forward control algorithm of add-blue basic supply mass flow,the feedback compensation algorithm based on NH3 coverage prediction model;as well as the transient thermal hysteresis correction algorithm of catalyst substrate and NH3 slip control strategy under transient conditions.These strategies could improve SCR control system robustness under transient conditions,and achieve the NOxconversion efficiency of more than 60% and mean NH3 slip value below25×10-6.The ESC and ETC tests show thatthis heavy duty diesel engine equipped with the developed SCR system could satisfy China stage IV emission regulation.

关 键 词：内燃机 柴油机 选择性催化还原 控制策略 模型 尿素喷射量 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]