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Development of the NOx Adsorber Catalyst for Use with High-Temperature Condition
Technical Paper
2001-01-1298
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Event:
SAE 2001 World Congress
Language:
English
Abstract
NOx adsorber has already been used for the after-treatment system of series production vehicle installed with a lean burn or direct injection engine [1,2,3]. In order to improve NOx adsorbability at high temperatures, many researchers have recently been trying an addition of potassium (K) as well as other conventional NOx adsorbents. Potassium, however, reacts easily with the cordierite honeycomb substrate at high temperatures, and not only causes a loss in NOx adsorbability but also damages the substrate.
Three new technologies have been proposed in consideration of the above circumstances. First, a new concept of K-capture is applied in washcoat design, mixed with zeolite, to improve thermal stability of K and to keep high NOx conversion efficiency, under high temperatures, of NOx adsorber catalyst. Second, another new technology, pre-coating silica over the boundary of a substrate and washcoat, is proposed to prevent the reaction between potassium and cordierite. The NOx adsorber catalyst, adopting these technologies, has demonstrated less crack formation and high NOx adsorbability at high temperatures even after severe accelerated aging test on the engine bench. The last one of the three technologies is the mixing of K retention compound and titanium compound in the washcoat with the aim of suppressing sulfur poisoning. The compound mixing in the washcoat has proven its effectiveness since K adsorbent has the advantage of easier sulfur desorption as compared with barium (Ba).
A newly developed NOx adsorber system is considered to be one of the potential technologies to deal with increasingly stringent NOx regulations for even high exhaust temperature applications.
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Authors
- Kinichi Iwachido - Mitsubishi Motors Corp.
- Hiroshi Tanada - Mitsubishi Motors Corp.
- Tetsuya Watanabe - Mitsubishi Motors Corp.
- Naoto Yamada - Mitsubishi Motors Corp.
- Osamu Nakayama - Mitsubishi Motors Corp.
- Hiromitsu Ando - Mitsubishi Motors Corp.
- Masao Hori - ICT Co., Ltd.
- Shigeyoshi Taniguchi - ICT Co., Ltd.
- Naomi Noda - NGK Insulators, Ltd.
- Fumio Abe - NGK Insulators, Ltd.
Citation
Iwachido, K., Tanada, H., Watanabe, T., Yamada, N. et al., "Development of the NOx Adsorber Catalyst for Use with High-Temperature Condition," SAE Technical Paper 2001-01-1298, 2001, https://doi.org/10.4271/2001-01-1298.Also In
Advanced Catalytic Converters and Substrates for Gasoline Emission Systems
Number: SP-1573; Published: 2001-03-05
Number: SP-1573; Published: 2001-03-05
References
- Matsumoto, S. et al. “Development of New Concept Three-Way Catalyst for Automotive Lean-Burn Engines” SAE Paper 950809 1995
- Matsumoto, S. et al. “Deactivation Mechanism of NOx Storage-Reduction Catalyst and Improvement of Its Performance” SAE Paper 2000-01-1196 2000
- Ohno, H. et al. “NOx Conversion Properties of a Mixed Oxide Type Lean NOx Catalyst” SAE Paper 2000-01-1197 2000
- Hara Nobuyoshi Takahashi Hiroshi “Zeolite” Kodansya 1975
- Nakajima Fumito “Development of TiO 2 Catalyst for NOx Removal Process” Catalysts 32 4 236 241 1990