车用柴油机选择性催化还原技术的试验研究

选择性催化还原技术(SCR)是当前主流的降低车用柴油机NOx排放的后处理技术。文章首先详细阐述了Urea-SCR系统的反应机理、系统组成和工作过程,然后在发动机台架上对装有SCR后处理系统的国Ⅳ柴油机进行了相关的试验研究。通过稳态ESC和瞬态ETC测试循环试验结果表明,利用开环控制策略下的SCR技术能使NOx排放降低率达到66%以上。同时对尿素与燃油的消耗量以及氨气的泄漏情况分别进行了比较和分析,试验表明本套SCR系统尿素水溶液消耗量仅占燃油的5.8%,即柴油车运行100km大约消耗2.5L尿素溶液,而系统氨的排放小于5×10-6。

An Experimental Research on Selective Catalytic Reduction Technology for Vehicular Diesel Engines

The Selective Catalytic Reduction（SCR） is currently mainstream after-treatment technology of DeNOx on vehicular diesel engines. Firstly the chemical reaction mechanism, system configuration and working process of Urea-SCR system are analyzed detailedly; then tests are conducted on a diesel engine which meets the China State 1V with SCR system on the engine test bench. The results of ESC and ETC cycles show that NOx emission is decreased by more than 66% with the open-loop control strategy. Additionally, the urea solution and fuel con- sumption and ammonia leakage have been compared and analyzed respectively, the experiment data indicates that the urea solution consumption ratio is only 5.8% of fuel for this SCR system, which is about 2.5 liters urea consumlation for 100 kilometers running of diesel vehicles, while its NH3 slip is below 5 x 10-6.