基于模型的船舶柴油机SCR系统控制方法研究

发布时间：2018-04-21 18:26

本文选题：船用柴油机 + SCR系统　；参考：《集美大学》2016年硕士论文

【摘要】：为控制船舶发动机日益严重的排气污染,国际海事组织(IMO)出台了MARPOL公约附则VI。目前,选择性催化还原(SCR)是船舶发动机达到附则VI规定的Tier III NO_x排放控制标准最有效的方法之一。本文通过建立SCR化学反应动力学模型和发动机排气特性模型,并结合发动机和SCR系统台架试验数据,开展了尿素喷射控制方法研究。首先,对SCR系统的化学反应过程进行了分析,建立了SCR化学反应动力学模型,并在Matlab/Simulink上分别建立了反应过程的NO_x模型、NH_3模型、储氨模型和温度模型,构成了SCR反应整体模型。其次,在分析影响柴油机排气特性主要因素的基础上,根据试验设计方案对原柴油机进行了排气特性试验,建立了BP神经网络柴油机排气特性模型,模型验证相对误差为6%,并在运转范围内进行了排气特性预测。再次,在SCR试验台架上进行了试验,对SCR模型参数进行了修正,模型参数修正结果为probcS×a=15.0432,kSCR=2.5852m2/s,Ea,SCR=31283J/mol,修正后的SCR模型预测值与SCR试验台架数据相对误差为12%。最后,以柴油机E3试验循环模式为例,根据发动机排气特性模型和SCR模型,确定该循环模式下的基本尿素喷射量,并结合瞬态修正和反馈修正,提出了初步的尿素喷射控制策略。
[Abstract]:In order to control the increasingly serious exhaust pollution of the ship's engine, the International Maritime Organization (IMO) issued the MARPOL Convention Annex VI. At present, selective catalytic reduction (SRR) is one of the most effective methods for marine engines to meet the Tier III NO_x emission control standard stipulated in Annex VI. In this paper, SCR chemical reaction kinetics model and engine exhaust characteristic model are established. Combined with the test data of engine and SCR system, the urea injection control method is studied. Firstly, the chemical reaction process of SCR system is analyzed, and the chemical reaction kinetics model of SCR is established, and the NO_x model, ammonia storage model and temperature model of the reaction process are established on Matlab/Simulink, respectively, which constitute the whole model of SCR reaction. Secondly, based on the analysis of the main factors affecting the exhaust characteristics of the diesel engine, the exhaust characteristics of the original diesel engine are tested according to the experimental design scheme, and the exhaust characteristic model of the diesel engine based on BP neural network is established. The relative error of model verification is 6 and the exhaust characteristics are predicted in the range of operation. Thirdly, the SCR model parameters were modified on the SCR test rig. The model parameters were revised to be probcS 脳 a 15.432kSCR = 2.5852 m ~ (-2) / s ~ (2) E ~ (2) 83J / mol. The relative error between the predicted value of the modified SCR model and the data of the SCR test rig was 12 ~ (2) cm ~ (-1). Finally, taking the E3 test cycle mode of diesel engine as an example, according to the engine exhaust characteristic model and SCR model, the basic urea injection quantity in the cycle mode is determined, and the transient correction and feedback correction are combined. A preliminary control strategy for urea injection is proposed.
【学位授予单位】：集美大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U664.121

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