Abstract: China Ⅵ vehicle emission standard natural gas engine adopts a three-way catalytic converter. There are oxidation and reduction reactions in the three-way catalytic converter, which can improve the durability of the aftertreatment. The study found that the activity of the active agent and the reaction efficiency of the pollutants at different temperatures are quite different. This paper summarizes the characteristics of the pollutants emitted by natural gas heavy-duty trucks, and analyzes and discusses the catalytic converter scheme to improve the conversion efficiency of the pollutants. Natural gas vehicle catalytic converters using three-way catalytic converters have two technical solutions: one-level and two-level. By analyzing the layout of the catalytic converter and the exhaust temperature after the supercharger, catalyst activity, and conversion efficiency of exhaust pollutants, it is determined that the two-stage catalytic converter technical solution for natural gas vehicles can improve the catalytic efficiency of the catalytic converter.

Key words: Natural gas engine; Two stage catalytic converter; Catalytic effliciency

摘要： 国六天然气发动机采用三元催化转化器，三元催化转化器中存在氧化和还原反应，可 以提高后处理的耐久性能。研究发现，不同温度下活性剂的活性和废气污染物的反应效率存 在较大差异，论文概述了重型燃气车排放污染物的特征，并针对提高污染物转化效率的后处 理方案进行分析和探讨。采用三元催化器的燃气车型后处理有单级和双级两种技术方案，通 过对后处理布置方案以及增压器后排气温度、催化剂活性、排气污染物转化效率分析，确定 燃气车采用双级后处理技术方案可以提高后处理催化效率。

关键词: 燃气发动机；双级后处理；催化效率