【摘要】 为了优化汽车尾气催化转化器设计,研究其中流动均匀性与催化剂起燃特性的关系。建立了冷启动过程催化剂载体温度场变化的数学模型。使用计算流体力学软件分析流动均匀性对载体温度场和催化剂转化效率的影响。实验中,通过改变载体端面形状,改变催化器内流动均匀性,并在发动机实验台上测试流动均匀性对起燃特性和催化剂转化效率的影响。计算和实验结果都显示:提高催化器内流动均匀性将明显延缓催化剂的起燃过程,从而增加起燃过程中尾气中污染物的排放。更多还原

【Abstract】 The relationship between the gas flow uniformity and catalyst lightoff characteristics is very important for the optimization of automotive catalytic converters. A mathematical model was developed to analyze the influence of gas flow uniformity on the temperature field in a monolith catalyst and on the catalyst conversion efficiency during warmup. Monolith catalysts with different configurations were used in experimental tests to generate different gas flow distributions distubations. The catalysts were installed in a catalytic converter in an engine test bench to measure the overall catalyst conversion efficiency. The simulation and the experimental results showed that although the improved gas flow uniformity increased the catalytic converter lifetime, it also retarded the catalyst lightoff time and reduced the overall conversion efficiency during warmup.更多还原