HC-adsorption type TWC system for reducing cold-start HC emissions

摘要

At Nissan, we have implemented the world's first hydrocarbon trap technology for reducing cold-start HC emissions. A new HC-adsorption type TWC uses an adsorber with high temperature durability to improve the holding characteristic of adsorbed HCs and a new oxygen storage material to enhance the conversion efficiency of desorbed HCs. In this new system, the GSA substrate has been optimized to improve adsorption efficiency, making it possible to reduce the catalyst volume significantly. Compared with a traditional HC adsorber system, the new system provides superior conversion of cold-start HCs. This paper presents an overview of these catalyst technologies.