改进型汽油机三效催化转化器反应模型及试验研究

Improved Reaction Model and Experimental Study of Gasoline Engine Three-Way Catalytic Converter

基于Langmuir-Hinshelwood机理,在一种详细三效催化转化器化学表面反应机理的基础上加入了助催化剂基元反应,建立了新的催化反应模型。利用气相化学动力学软件对反应流进行了数值模拟,得到了原机理与新机理下反应物物质的量浓度随发动机冷起动瞬态工况的变化情况。进行了发动机冷起动台架试验,将模拟值与试验值进行比较,发现新反应机理相对于原反应机理具有更好的冷起动瞬态响应性。对预测三效催化转化器活性具有重要的参考价值,并对三效催化转化器的优化设计提供了指导。

An improved reaction kinetic model was developed by adding the elementary reactions of cata- lytic promoter in the three-way catalytic converter based upon the Langmuir-Hinshelwood mechanism and a detailed surface reaction mechanism. A computational gas phase kinetics software is used to simulate the reacting flow and the molar concentrations of reactants under the cold start condition using original and new reaction mechanisms is obtained. Bench experiment of cold start was conducted. Simulation results have good agreement with experimental data. The new reaction mechanism has the better transient response than that of the original reaction mechanism. The study has the reference to predict the activity of the TWC, and provide guidance for the optimal design of the catalytic converter.