High-efficient and Cost-effective Three-Way Catalyst Substrate Design for Plug-in Hybrid Electric Vehicle

China 6b regulation was fully implemented since July 2023 with very strict emission standards for HC, NMHC, NOx, and CO. The country is now also in the process of developing China 7 regulation, which will perhaps impose even stricter emission limits and extra criteria pollutants including NH3. Moreover, increasingly strict fuel consumption regulation has been implemented as well and it is highly possible that greenhouse gas emission limits will be included in the China 7 regulation. With the hybrid technology innovation, PHEVs are effective in fuel economy and emission reduction, which are favored by manufacturers and consumers, and leading to a rapid increase in market share. Through the optimization of hybrid architecture and the synergy of electric motors, the operating conditions of the hybrid engine have been optimized, making it more stable and avoiding extreme engine operating conditions compared to traditional ICE, which also provides possibilities for optimizing the after-treatment system design to achieve low cost and high efficiency at the same time. In this study, engine operating conditions and engine out emissions of a PHEV were analyzed through vehicle testing with WLTC cycle in lab. Emission tests were conducted using different catalyst systems to study the impact of different substrate design options including low mass Corning® FLORA® substrates with higher cell density on gaseous pollutant emissions. As a byproduct of secondary reactions on catalysts, the generation of NH3 is closely related to catalyst efficiency. This study also investigated the characteristics of NH3 emissions and proposed appropriate design to reduce NH3 emission. Additionally, the influence of thermal aging conditions on catalyst conversion efficiency was studied to explain the correlation between anti-ageing performance and the substrate design.