在发动机测试台架上对比研究不同温度、空速、氨氮比下铜基分子筛SCR催化剂和钒基SCR催化剂的NOx转化效率和氨存储特性。试验结果表明，对于铜基SCR催化剂，在低温区域200~250 ℃，温度对氮氧转化率影响明显，而空速影响甚微。温度对氨储存量影响极大，铜基SCR催化剂氨存储量随温度上升而快速下降，200 ℃时为1.5 g/L， 250 ℃为0.77 g/L。对比而言，铜基催化剂低温性能优异，转化效率达到84%，明显高于钒基催化剂低温40%~60%转化效率；中温段（250~450 ℃）性能稳定，转化效率达到98%；高温段（450 ℃以上）效率较高，达到96%，且随着温度升高效率降低幅度较小。铜基分子筛催化剂性能整体优于钒基催化剂，从技术角度考虑，为国六后处理催化剂的优先选择。本试验研究工作获得的基础数据，可用于发动机数据标定。

The bench test was conducted to investigate NOx conversion efficiency and NH₃ storage characteristics of copper-based molecular sieve and vanadium-based SCR catalysts under different temperatures, space velocities and ANRs. The results showed that the low temperature area between 200 ℃ and 250 ℃ had an obvious effect on NOx conversion and the space velocity had little influence for copperbased SCR catalyst. In addition, temperature had a remarkable influence on NH₃ storage amount, and the NH₃ storage amount of copper-based SCR catalyst decreased rapidly with the increase of temperature. NH₃ storage amount was 1.5 g/L at 200 ℃, but decreased to 0.77 g/L at 250 ℃. Compared with vanadium-based catalyst with 40%-60% conversion rate at low temperature, copper-based catalyst showed much better low-temperature performance with conversion efficiency up to 84%. Besides, copper-based catalyst had stable performance with conversion efficiency of 98% at middle temperature about 250 ℃ to 450 ℃ and could also achieve conversion efficiency of 96% at high temperature higher than 450 ℃, and the decrease scope of conversion efficiency for copper-based catalyst is minor with the increase of temperature. Accordingly, copper-based molecular sieve catalyst had better performance than vanadium-based catalyst, which should be the priority choice for the posttreatment of China Ⅵ diesel engine from a technical point of view. The basic data obtained in this test study could be used to calibrate the engine.