国产车用尿素可替代性试验研究

使用商业钒基SCR催化转化器和某国Ⅳ重型柴油机,在AVL发动机台架上对3种国产车用尿素进行了相互替代性试验,研究中考虑了不同尿素对SCR催化转换器的起燃特性、动态响应、NOx转化率和NH3泄漏等性能的影响。试验排气温度为160～440℃,n(NOx)∶n(NH3)(物质的量之比)从0.8变化到1.2。研究发现:相同条件下3种尿素对SCR系统起燃温度基本没有影响,ESC和ETC循环NOx转化率都在70%以上,同时对其他常规气态排放和NH3泄漏没有明显影响,可以互相替代使用;相同条件下,单位体积尿素溶液中尿素含量越高,SCR系统动态响应越快,ESC和ETC循环NOx转化率越高。

Experimental Study on Substitutability of Domestic Urea for Vehicle

For a commercial vanadium SCR catalytic converter and a state Ⅳ heavy duty engine,the mutual substitutability experiments for three kinds of domestic vehicle urea were carried out on AVL engine bench.The influences of different urea on ignition performance,dynamic response,NOx conversion efficiency and NH3 leakage for SCR converter were taken into account in the research.In the experiment,the exhaust temperature ranged from 200 to 440 ℃ and n(NOx)∶n(NH3) ranged from 0.8 to 1.2.The results show that,under the same conditions,the ignition temperature is little influenced by different urea,the conversion efficiency of NOx is beyond 70% in ESC and ETC cycles and other common exhaust emissions and NH3 leakage arenot influenced significantly,which proves the mutual substitutability between those urea.In addition,the higher the urea content per volume solution,the faster the dynamic response of the SCR system and the higher the conversion efficiency of NOx in ESC and ETC cycles.