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This paper presents a computational investigation of the effect of engine exhaust gas modulations on the performance of an automotive catalytic converter during cold starts. The objective is to assess if the modulations can result in faster catalyst light-off conditions and thus reduce cold-start emissions. The study employs a single-channel based, one-dimensional, non-adiabatic model. The modulations are generated by forcing the variations in exhaust gases air-fuel ratio and gas compositions. The results show that the imposed modulations cause a significant departure in the catalyst behavior from its steady behavior, and modulations have both favorable and harmful effects on pollutant conversion during the cold-starts. The operating conditions and the modulating gas composition have substantial influence on catalyst behavior.

This paper presents a computational investigation of the effect of space velocity on the dynamic performance of an automotive catalytic converter. The objective is to develop a better fundamental understanding of the converter's performance under actual driving conditions. The study employs a single-channel based, one-dimensional, non-adiabatic model. The transient effects are considered by modulating the air-fuel ratio and compositions of the exhaust gases entering the catalyst. The results elucidate the role of space velocity in determining the catalyst behavior under transient conditions. At high space velocities, the catalyst performance is relatively more influenced by imposed transients.