This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Development of Three-Way Catalyst with Advanced Coating Layer
Technical Paper
2020-01-0653
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Further improvements in catalyst performance are required to help protect the atmospheric environment. However, from the viewpoint of resource availability, it is also necessary to decrease the amount of precious metals used at the active sites of the catalyst. Therefore, a high-performance three-way catalyst with an advanced coating layer has been developed to lower the amount of precious metal usage. Fuel efficiency improvement technologies such as high compression ratios and a large-volume exhaust gas recirculation (EGR) generally tend to increase the ratio of hydrocarbons (HC) to nitrogen oxides (NOx) in exhaust gas. This research focused on the palladium (Pd) loading depth in the coating layer with the aim of improving the hydrocarbon (HC) conversion activity of the catalyst. Contact between Pd, which has a high degree of HC conversion activity, and the exhaust gas can be facilitated by controlling the loading depth on the surface of the coating layer, enabling efficient conversion even under high space velocity (SV) conditions. Subsequently, this research focused on the coating structure to maximize the conversion activity and oxygen storage capacity (OSC) performance and improve gas diffusivity in the coating layer. The particle size of each coating material was controlled to maximize the heat resistance and OSC performance. The coating thickness was controlled by applying finer alumina and fabricating connected pores. This coating structure ensures excellent gas diffusivity without affecting the pressure drop. As a result, the developed catalyst achieves high conversion activity with nearly 20% less precious metal usage. This catalyst will start to be introduced in vehicles from 2020.
Recommended Content
Authors
Citation
Saito, Y., Chinzei, I., Morikawa, A., Ito, M. et al., "Development of Three-Way Catalyst with Advanced Coating Layer," SAE Technical Paper 2020-01-0653, 2020, https://doi.org/10.4271/2020-01-0653.Also In
References
- Aoki , Y. et al. Development of Double-Layered Three-Way Catalysts SAE Technical Paper 2009-01-1081 2009 https://doi.org/10.4271/2009-01-1081
- Fujiwara , T. et al. Development of High Performance Three-Way-Catalyst Technology to Lower NOx Emission SAE Technical Paper 2009-01-1398 2009 https://doi.org/10.4271/2009-01-1398
- Miura , M. et al. Development of Advanced Three-Way Catalyst with Improved NOx Conversion SAE Int. J. Passeng. Cars - Electron. Electr. Syst. 8 2 229 239 2015 https://doi.org/10.4271/2015-01-0133
- Heywood , J.B. Internal Combustion Engine Fundamentals McGraw-Hill 1988
- Yokoyama , S. et al. Measurement of Apparent Porosity, Water Absorption and Densities of Refractory Bricks Yogyo-Kyokai-Shi 93 655 660 1985
- Kato , S. et al. Characterization of Secondary Pores in Washcoat Layers and their Effect on Effective Gas Transport Properties Chemical Engineering Journal 324 370 379 2017
- Morikawa , A. , et al. Development of High Heat-resistant Pyrochlore Type Oxygen Storage Material pCP 26th Fall Meeting of the Ceramic Society of Japan 2014
- Chinzei , I. et al. Development of Three-Way Catalyst Enhanced NOx Purifying Activity SAE Technical Paper 2018-01-0942 2018 https://doi.org/10.4271/2018-01-0942