Non-road machinery is very important, but non-road machinery has problems such as working under complex operating conditions. Agricultural machinery is an important type of non-road machinery, which mainly relies on diesel engines due to their high fuel efficiencies. The exhaust temperature of agricultural machinery changes drastically under different working conditions. This article aims to research on pollution control of non-road machinery. Among the exhaust after treatment technologies, selective catalytic reduction (SCR) technology is a very important method to reduce NO_x. In this study, a series of tests was conducted to investigate the effects of temperature and exhaust gas mass flow on the NO_x conversion and dynamic ammonia storage space distribution characteristics in simulation models. The genetic algorithm, a kind of global optimization algorithm that can avoid local optimization, was used in the parameter identification process. The simulation results showed that the ammonia storage capacity of SCR catalyst decreases as the temperature of SCR increases. With the decrease in temperature, the NH₃ desorption rate gradually decreased. An uneven distribution of ammonia storage similar to the shape of ɛ was observed in the simulation and this kind of uneven distribution is obvious at low temperature. The effective area of the catalyst is near the inlet of the catalyst. This work presents an approach to help figure out the details in the ammonia storage process. This work provides information about the dynamic ammonia storage characteristics and guide for better SCR design.

中文翻译：

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柴油机选择性催化还原氨储存特性模拟研究

非道路机械很重要，但非道路机械存在工作条件复杂等问题。农业机械是一种重要的非道路机械，主要依靠柴油发动机，具有较高的燃油效率。农机的排气温度在不同的工况下会发生剧烈的变化。本文旨在研究非道路机械的污染控制。间处理技术后的排气，选择性催化还原（SCR）技术是降低NO一个非常重要的方法_X。在这项研究中，一系列的测试法，研究温度和废气质量流的对NO的影响_X模拟模型中的转化和动态氨储存空间分布特征。遗传算法是一种可以避免局部优化的全局优化算法，用于参数识别过程。模拟结果表明，SCR催化剂的氨储存能力随着SCR温度的升高而降低。随着温度的降低，NH ₃解吸率逐渐下降。在模拟中观察到类似于ɛ形状的氨储存不均匀分布，这种不均匀分布在低温下很明显。催化剂的有效面积在催化剂入口附近。这项工作提出了一种方法来帮助弄清楚氨储存过程中的细节。这项工作提供了有关动态氨储存特性的信息，并为更好的 SCR 设计提供了指导。