Development of TWC and PGM Free Catalyst Combination as Gasoline Exhaust Aftertreatment

Paper #:
  • 2016-01-2323

Published:
  • 2016-10-17
DOI:
  • 10.4271/2016-01-2323
Citation:
Nakayama, H., Kanno, Y., Nagata, M., and Zheng, X., "Development of TWC and PGM Free Catalyst Combination as Gasoline Exhaust Aftertreatment," SAE Int. J. Engines 9(4):2194-2200, 2016, doi:10.4271/2016-01-2323.
Pages:
7
Abstract:
Reduction of the amount of platinum group metals (PGM: Pt, Pd, Rh) utilized in three-way catalysts (TWC) has been required from a point of resource shortage and cost effectiveness. A conventional TWC system is composed of a close-coupled (CC) catalyst and an underfloor (UF) catalyst, both PGM-based. The CC-TWC promotes HC/CO oxidation and NOx reduction by CO. The UF-TWC mainly facilitates further NOx reduction by CO.In this study, a TWC system comprising a CC catalyst with PGM and an UF catalyst without PGM has been described. The newly developed system, performing reasonably well with a conventional stoichiometric gasoline combustion engine, offers an opportunity to reduce PGM usage. In this system, the UF-non-PGM catalyst is composed of a Ni/CeO2 bottom layer which functions as a deNOx catalyst with CO-NO reaction and a zeolite based top layer which works as a deNOx catalyst with passive NH3-SCR reaction. The CC catalyst operates as a conventional TWC but also generates a certain amount of NH3 under rich conditions, and the generated NH3 is used as the reductant for the SCR reaction on the UF-non-PGM catalyst. The NH3 generation on the CC-TWC and the specific deNOx concept in UF-non-PGM catalyst were validated by model gas reactor test, and the performance of the CC-TWC + UF-non-PGM catalyst system was evaluated by chassis test. It was found that such a system showed promising performance in LA4 and US06 evaluations. The NOx conversions of the UF-non-PGM catalyst were 85% and 40% in LA4 and US06 modes, respectively.
Access
Now
SAE MOBILUS Subscriber? You may already have access.
Buy
Select
Price
List
Download
$27.00
Mail
$27.00
Members save up to 40% off list price.
Share
HTML for Linking to Page
Page URL

Related Items

Standard
2010-11-05
Technical Paper / Journal Article
2003-10-27
Training / Education
2010-03-15
Technical Paper / Journal Article
2003-10-27
Book
2005-06-17