关键词: 燃气发动机；双级后处理；催化效率

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