基于模型的重型柴油车SCR后处理系统稳态控制策略研究

摘要

为满足即将实施的中重型柴油车国Ⅳ排放法规要求，建立了一种基于模型的SCR尿素喷射稳态控制策略，研究了稳态下影响尿素喷射的排温模型、NOx 预估模型、排气流量模型、催化器效率模型和喷射模型，分析了空速比等影响模型性能的重要参数，建立了模型控制的MAP图和数学计算方法。将SCR系统进行了台架试验，研究了ESC工况下NOx 浓度变化趋势。研究结果表明，基于模型控制策略的SCR系统对于降低NOx 排放具有良好的效果，并可以达到国Ⅳ排放法规要求。%In order to meet the impending State Ⅳ emission legislation for middle and heavy duty vehicle ,a steady state con-trol strategy of urea injection for SCR based on model was established .The exhaust temperature ,NOx pre-estimation ,exhaust flow ,catalyst efficiency and injection models were researched ,the important parameter affecting model effect like space velocity was analyzed ,and the MAP and mathematic calculation method controlled by model were built .The SCR system was verified in the test bench and the NOx trend in ESC cycle was researched .The results show that the SCR system based on model control strategy has a better effect on reducing NO x emission and can meet the requirement of State Ⅳ .