基于氨存储模型的SCR系统尿素喷射控制策略研究

Research on Control Strategy of SCR System Urea DosingBased on Ammonia Storage

以某型号6缸高压共轨柴油机为研究对象,开发了一种基于氨存储模型的SCR系统尿素喷射控制策略。通过氨存储量对目标转化效率和尿素喷射量的修正,实现了尿素喷射量的精准控制。试验结果表明:台架试验稳态循环NO_(x)排放1.132 g/(kW·h),瞬态循环NO_(x)排放1.639 g/(kW·h),均低于非道路国四阶段法规要求;同时,该控制策略的尿燃比达到了5.56%,相比于开环控制,提高了经济性,有效地降低了尿素结晶的风险。

A urea injection control strategy for SCR system based on ammonia storage model was developed for a type of 6-cylinder high pressure common rail diesel engine.By modifying the conversion efficiency and urea injection amount with ammonia storage capacity,the precise control of urea injection amount was realized.The test results show that the steady-state cycle NO_(x)emission of bench test is 1.132 g/(kW·h),and the transient cycle NO_(x)emission is 1.639 g/(kW·h),both of which are lower than the four-stage regulations of non-road countries.At the same time,the urine-fuel ratio of this control strategy reached 5.56%,which improved the economy and effectively reduced the risk of urea crystallization compared with open-loop control.