满足超低NOx排放标准的紧凑耦合SCR系统控制策略研究  

Study on Control Strategy of CCSCR System to Meet Ultra-low NOx Emission Standard

作　　者：刘世宇 王国仰 谭致 张兆欢 帅石金[1] 王志明[2] Liu Shiyu;Wang Guoyang;Tan Zhi;Zhang Zhaohuan;Shuai Shijin;Wang Zhiming(Tsinghua University,State Key Laboratory of Automotive Safety and Energy,Beijing 100084;The School of Energy and Power Engineering,Shandong University,Jinan 250061)

机构地区：[1]清华大学,汽车安全与节能国家重点实验室,北京100084 [2]山东大学能源与动力工程学院,济南250061

出　　处：《汽车工程》2020年第12期1630-1637,1694,共9页Automotive Engineering

基　　金：国家重点研发计划(2017YFC0211105和2017YFC0211103)资助。

摘　　要：紧凑耦合选择性催化还原(ccSCR)技术是满足加州超低NOx排放标准的一种切实可行的后处理技术,本文通过数值仿真计算的方法对ccSCR系统控制策略进行研究。利用SCR单状态模型对催化器NH3存储、NOx排放和NH3泄漏进行预测,分析了未安装ccSCR催化器时美国联邦测试循环(FTP)NOx排放特性,基于此提出了双喷嘴独立控制策略和双喷嘴联合控制策略。研究结果表明,ccSCR系统可以充分利用尾气热量,大大缩短尿素起喷时间,FTP循环冷起动尿素起喷时间从568降低到51 s。双喷嘴联合控制策略将ccSCR催化器和下游SCR催化器中的NH3存储进行联合控制,采用该策略的ccSCR系统NOx转化效率达到99.56%,NOx比排放满足未来加州超低NOx排放法规要求。Close-coupled selective catalytic reduction(ccSCR)technology is a feasible post-processing technology to meet California’s ultra-low NOx emission standard.In this paper,the control strategy of ccSCR system is studied by numerical simulation.SCR single state model is used to predict NH3 storage,NOx emission and NH3 leakage.The NOx emission characteristics of federal test procedure(FTP)are analyzed when ccSCR catalyst is not installed.Based on the analysis,the dual-nozzle independent control strategy and dual-nozzle joint control strategy are proposed.The results show that ccSCR system can make full use of exhaust gas heat and greatly reduce the starting time of urea injection,with the starting time of urea injection reduced to 51 from 568 s on cold-start FTP.The dual-nozzle joint control strategy will jointly control the NH3 storage in the ccSCR and the downstream SCR catalyst.The NOx conversion efficiency of the ccSCR system can reach 99.56%by using this strategy,and the specific NOx emission meets the requirements of the future California ultra-low NOx emission standard.

关 键 词：重型柴油机 超低NOx排放 紧凑耦合选择性催化还原 双喷嘴系统 控制策略 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]