This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Zone Length Optimization to Improve PGM Utility
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 01, 2014 by SAE International in United States
Annotation ability available
“Zoning” a catalytic converter involves placing higher concentrations of platinum group metals (PGM) in the inlet portion of the substrate. This is done to optimize the cost-to-performance tradeoff by increasing the reaction rate at lower temperatures while minimizing PGM usage. A potentially useful application of catalyst zoning is to improve performance using a constant PGM mass. A study was performed to assess what the optimum ratio of front to rear palladium zone length is to achieve the highest performance in vehicle emission testing. Varying the zone ratio from 1:1 to 1:9 shows a clear hydrocarbon performance optimum at a 1:5.66 (15%/85%) split. This performance optimum shows as both a minimum in FTP75 non-methane organic gas (NMOG) emissions as well as a minimum in hydrocarbon, carbon monoxide, and nitrogen oxide light-off temperature. Overall, an improvement of 18%, or 11 mg/mi of combined NMOG+NOx emissions was obtained without using additional PGM. This study shows how the competing forces of active PGM site concentration and available surface area interact in modern three way catalyst design.
CitationJohnson, S., Croswell, P., and Smith, M., "Zone Length Optimization to Improve PGM Utility," SAE Technical Paper 2014-01-1508, 2014, https://doi.org/10.4271/2014-01-1508.
- Aoki , Y. , Sakagami , S. , Kawai , M. , Takahashi , N. et al. Development of Advanced Zone-Coated Three-Way Catalysts SAE Technical Paper 2011-01-0296 2011 10.4271/2011-01-0296
- Zammit , M. , Wuttke , J. , Ravindran , P. , and Aaltonen , S. The Effects of Catalytic Converter Location and Palladium Loading on Tailpipe Emissions SAE Technical Paper 2012-01-1247 2012 10.4271/2012-01-1247
- Stillwater Mining The Case for Palladium - 2011 Update http://www.stillwatermining.com/market/the-case-for-palladium-2011-update.html Sept 2013
- BASF Catalysts Engelhard Industrial Bullion Prices http://apps.catalysts.basf.com/apps/eibprices/mp/ Sept 2013
- Ball , D. , Zammit , M. , Wuttke , J. , and Buitrago , C. Investigation of LEV-III Aftertreatment Designs SAE Int. J. Fuels Lubr. 4 1 1 8 2011 10.4271/2011-01-0301
- Manufacturers of Emission Controls Association LEV III and Tier 3 Exhaust Emission Control Technologies for Light-Duty Gasoline Vehicles http://www.meca.org/galleries/files/LEV_III_Tier_3_white_paper_final.pdf September 2013
- Gulati , S. , Jones , L. , Brady , M. , Baker , R. et al. Advanced Three-Way Converter System for High Temperature Exhaust Aftertreatment SAE Technical Paper 970265 1997 10.4271/970265
- Joshi , S. , Harold , M. , Balakotaiah , V. Overall Mass Transfer Coefficients and Controlling Regimes in Catalytic Monoliths Chemical Engineering Science 65 1729 1747 2010 10.1016/j.ces.2009.11.021
- Faghri , A. , Zhang , Y. Transport Phenomena in Multiphase Systems Elsevier Burlington, MA 2006
- Faghri , A. , Zhang , Y. , Howell , J. Advanced Heat and Mass Transfer Global Digital Press Columbia, MO 2010
- Mills , A. 1999 Basic Heat and Mass Transfer 2nd Prentice Hall Upper Saddle River, NJ