The Development of a Zeolite-Based Cold-Start Catalyst (CSC) for China 6b Vehicles (Conventional & Hybrid) to Meet the Next Chinese Vehicle Emission Standard, Part II

This is a follow-up report about the development of a cost-effective Palladium (Pd) zeolite-based (HC/NOx trap type) cold-start catalyst (CSC) [1] to meet the future more stringent Chinese vehicle tailpipe emission standard. The impacts of Pd /stabilizer combination within zeolite for the HC/NOx trapping efficiency, the high temperature aging and the durability of the CSCs will be demonstrated by the laboratory results within this paper. The feasibility of a Cu zeolite, a popular non-precious metal ion- zeolite CSC for vehicle applications with respect to cost saving options will be demonstrated. A more complete picture of the effects of PGM/stabilizer within the zeolite to the functions of a CSC will also be summarized in this paper. All results indicate clearly that without the PGM/stabilizer within the zeolite, it would be difficult for the zeolite-based HC/NOx trap type CSC catalyst to be practically used for a vehicle application. The bag and second by second vehicle test results with a Pd/stabilizer-zeolite based CSC showing the decrease in cold-start emissions on a China 6b hybrid vehicle (HEV) will meet the projected future more stringent Chinese tailpipe emission standard. The future development plan for a CSC as a new catalyst technology in vehicle applications will also be outlined.