关键词: 汽车尾气;冷启动, 排气系统, 数值模拟, 温度场, 浓度场

Abstract: The engine emission in the cold-start phase plays an important role in reducing the overall emission in the tailpipe.Simulating cold-start engine behavior is a difficult task as it involves heat transfer processes and chemical reactions at both the exhaust pipe and catalytic converter.This paper presents a mono-channel non-steady model for the heat and mass transfer in the exhaust system of cold-start phase engine，both spatially and temporally. With the aid of numerical calculations, thermal and mass transfer characteristics of the exhaust system were analyzed.The calculation results were in agreement with experiments.The conversions of carbon monoxide, unburned hydrocarbons and nitrogen oxides were supported by the experimental data.The temperature and concentration distributions in the three-way monolithic converter were also discussed,which are necessary for the research and design of converter.

Key words: 汽车尾气;冷启动, 排气系统, 数值模拟, 温度场, 浓度场