脉冲喷射C3H6的新型NSR技术研究  

New NSR Technology of C3H6 Pulse Jet

作　　者：陈顺 宋桂金 刘旻 叶敬安 刘兴 胡琨 管斌[1] 湛日景 林赫[1] 黄震[1] CHEN Shun;SONG Guijin;LIU Min;YE Jing’an;LIU Xing;HU Kun;GUAN Bin;ZHAN Rijing;LIN He;HUANG Zhen(Key Laboratory of Power Machinery and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Technology Center of SAIC Motor Co.,Ltd.,Shanghai 201804,China)

机构地区：[1]上海交通大学动力机械与工程教育部重点实验室,上海200240 [2]上海汽车乘用车公司技术中心,上海201804

出　　处：《车用发动机》2020年第2期9-14,48,共7页Vehicle Engine

基　　金：国家重点研究发展计划(2016YFC0205200,2016YFC0208000);移动源排放控制技术国家工程实验室开放基金项目(NELMS2017A07);国家自然科学基金(51176118);国家自然科学青年基金(51306115);低速船用发动机项目(CDGC01-KT1203);上海汽车集团股份有限公司宽范围空燃比的高效催化器技术项目(4900049365)。

摘　　要：稀燃发动机具有燃料消耗量低的优点,但其缺点是NOx排放值较高。传统SCR技术由于体积较大无法在轻型乘用车上应用,针对稀燃发动机的NOx去除主要是通过NSR催化剂来实现,但是其难以解决的问题是高温和高空速时的NOx转化率较低。通过试验研究,提出了一种针对稀燃发动机排气中NOx去除的新型NSR技术,其原理是通过在NSR催化剂前端以一定的频率脉冲喷射碳氢还原剂,在NSR催化剂上能形成具有还原性的活性中间物种-CN和-NCO,C3H6脉冲喷射期间,活性还原物种不断生成、消耗,从而来还原NSR催化剂上吸附的NOx,NSR催化剂实现再生。采用此项技术,发动机可一直运行在稀燃工况,避免切换至浓燃状态,而且运行简单,控制成本较低。研究结果表明此技术拓宽了NOx去除的温度窗口,在排气温度为350~550℃区间均能保持90%以上的NOx转化效率。另外,对此系统的关键影响参数也进行了探究:反应温度、空速、碳氢燃料喷射频率与喷射量、空燃比。The lean-burn engine has the advantage of low fuel consumption and also the disadvantage of high NOx emission.The traditional SCR technology cannot be applied to light passenger vehicle due to its large size.The NOx removal of lean-burn engine is mainly achieved by NSR catalyst,which cannot achieve high NOx conversion rate yet at high temperature and high space velocity.Through the experimental research,a new NSR technology for NOx removal of lean-burn engine exhaust was proposed.By injecting a hydrocarbon reductant at the front end of NSR catalyst with a certain frequency,the reductive and active intermediate species such as-CN and-NCO formed on the NSR catalyst.The intermediate species generated continuously and were consumed to reduce the NOx pollutants adsorbed on the NSR catalyst during the pulse jet of C3H6 and the NSR catalyst then regenerated.By adopting this technology,the engine could be running in a lean-burn condition,which meant that it was not necessary to switch to the rich-burn condition.Therefore the operation was simple and the control cost was low.The experimental results show that this system can broaden the temperature window of NOx removal and maintain NOx conversion efficiency of more than 90%in the range of exhaust gas temperature between 350℃and 550℃.In addition,the key influencing parameters of the system are also explored including the reaction temperature,the space velocity,the hydrocarbon fuel injection frequency and quantity and the air-fuel ratio.

关 键 词：稀燃发动机 NSR催化剂 脉冲喷射 活性物种 局部金属化 

分 类 号：TK411.5[动力工程及工程热物理—动力机械及工程]