柴油机尿素SCR系统动态氨泄漏的试验研究  

Experimental Study of Ammonia Slip of Diesel Engine Urea Selective Catalytic Reduction System in Transient Condition

作　　者：赵彦光[1] 胡静[1] 华伦[1] 帅石金[1] 王建昕[1] 

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

出　　处：《内燃机工程》2012年第3期20-25,共6页Chinese Internal Combustion Engine Engineering

摘　　要：通过台架试验定量研究了瞬态工况尿素选择催化还原系统中氨泄漏与氨存储量的关系。研究了初始温度分别为200、240、270和320℃时,催化器氨存储饱和后快速升温到400℃过程中的氨泄漏情况;在相同变工况条件下,分析了氨存储饱和度对氨泄漏的影响;基于台架测试结果,对变工况过程中的尿素喷射控制策略进行了修正。研究结果表明:不同的升温过程氨泄漏程度不同,初始温度越低,在快速升温过程中越容易产生氨泄漏;氨存储饱和度对氨泄漏的影响很大,试验中氨存储饱和度小于58%时,瞬态工况不会出现氨泄漏。ESC测试结果表明:修改后的控制策略使催化器出口NH3的体积浓度降低到10×10-6以下,同时NOx转化效率没有明显下降。The relation between ammonia slip and ammonia storage quantity of urea selective catalytic reduction （SCR） system in transient condition was studied in engine test bench. The ammonia slip was measured in quick heating up processes of the SCR catalyst from 200 ℃, 240℃, 270℃ and 320℃ to 400℃ respectively. The effect of ammonia storage saturation level on catalyst surface on ammonia slip in transient condition was analyzed, and based on it the urea injection strategy was modified. Experimental results show that heating temperature increment results in different ammonia slips. The lower the initial temperature, the greater the ammonia slip. The ammonia storage saturation level has significant effect on the ammonia slip in transient condition. In the experiment, when the saturation level is lower than 58 ~ of the storage capacity, the ammonia slip is nearly zero. The ESC test shows that the revised urea injection strategy makes the ammonia volumetric concentration in outlet of the SCR system lower than 10 × 10^-6 in the whole test process without obvious decrease of NOx conversion efficiency.

关 键 词：内燃机 柴油机 选择催化还原 尿素 氨泄漏 氨存储 

分 类 号：TK421.5[动力工程及工程热物理—动力机械及工程]