HCA材料的制备与应用（英文）

Preparation and Application of the HCA Catalyst Materials

为满足越来越严格的汽车尾气排放标准且有效降低冷启动时碳氢化合物(HC)排放以及解决神龙、奇瑞车型在冷启动时钯基催化剂的碳氢吸附(HCA)性能消失的缺点,重点探究了所制备的HCA催化剂在发动机台架上的催化性能、HC吸附性能以及其在整车上的应用。在本研究中,采用沸石和贵金属连接体的Pd/I-Ce-HZSM-5为HCA材料的主要组分,对神龙和奇瑞车型而言,其排放结果表明:冷启动时,Pd/I-Ce-HZSM-5型HCA催化剂对HC捕集效果明显优于传统方式制备的催化剂,由于钯基催化剂具有良好的起燃特性,碳氢吸附的连接体及低起燃性使得Pd/I-Ce-HZSM-5催化剂的碳氢排放进一步减少。冷启动20~30 s时,沸石负载钯基催化剂的碳氢吸附量最大。HCA材料对于满足高标准的低温HC排放质量方面具有很大的研究潜力。

To adsorb the excess hydrocarbons emitted during a period of engine cold-start and to solve the fault that Hydrocarbon（HC） adsorption behavior on Pd-based catalyst appears during a cold-start period of actual driving cycle in the vehicles of Dragon and Cherry,Hydrocarbon Absorber（HCA） material were leaded in catalytic performance of prepared HCA catalyst and HC adsorption process were tested,and then their applications were studied in the whole vehicle. In this work,Pd/Ce-HZSM-5 was used as the main recipes of HCA materials as well as a combination of zeolite and precious metals. Since Pd-based catalyst shows relatively good light-off performance,the combination of HC adsorption and early light-off activity has led to an improvement of overall HC emission reduction to Pd/Ce-HZSM-5. Usage of zeolite combined with Pd-based catalyst maximizes HC adsorption between 20~30 s during the cold-start period for fresh catalyst. For Dragon and Cherry models,their emission results show Pd/Ce-HZSM-5 catalyst is superior to Al_2O_3 molecular sieve catalyst for HC trap. HCA material has great research potential to meet high standards of HC emissions quality at low temperature.