船舶SCR尿素喷射控制策略研究

Research on Control Strategy of Marine SCR Urea Injection

为了研究优化船舶柴油机选择性催化还原(SCR)尿素喷射控制策略,在闭环PID控制策略的基础上针对其延时性较大的缺点设计了前馈加PID闭环控制策略,并搭建台架对两种控制策略进行对比研究。结果表明:在D2循环下氨的溢出体积分数始终小于10^(-5),NO_(x)的加权比排放量为1.17g/(kW·h),满足TireⅢ排放标准;D2瞬态试验循环工况下,相比较于传统闭环PID控制策略,前馈加PID闭环控制策略具有更好的鲁棒性和实效性,在瞬态工况下的控制效果更好。

In order to study and optimize the marine diesel engine selective catalytic reduction(SCR)urea injection control strategy,on the basis of the closed-loop PID control strategy,a feedforward plus PID closedloop control strategy was designed for its large delay,and a bench was built to carry out A comparative study of two control strategies.The results showed that under the D2 cycle,the overflow volume fraction of ammonia was always less than 10^(-5),and the weighted specific emission of NO_(x) was 1.17 g/(kW·h),which met the TireⅢemission standard.Under the D2 transient test cycle condition,compared with the traditional closed-loop PID control strategy,the feedforward plus PID closed-loop control strategy had better robustness and effectiveness,and the control effect was better under transient conditions.