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Robust Packaging System for Diesel/Natural Gas Oxidation Catalysts
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1996 by SAE International in United States
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The 290,000 vehicle-mile durability requirement for diesel/natural gas oxidation catalysts calls for robust packaging systems which ensure a positive mounting pressure on the ceramic flow-through converter under all operating conditions. New data for substrate/washcoat interaction, intumescent mat performance in dry and wet states, and high temperature strength and oxidation resistance of stainless steels, and canning techniques insensitive to tolerance stack-up are reviewed which help optimize packaging durability. Factors contributing to robustness of converter components are identified and methods to quantify their impact on design optimization are described.
CERAMIC FLOW-THROUGH catalysts for diesel exhaust aftertreatment have met with much success since their introduction in 1993. Both performance and durability requirements have been met via optimization of engine management, substrate design, washcoat formulation, catalyst selection, and packaging robustness[1, 2, 3 and 4]* Further tightening of emissions regulation, notably particulate matter and NOx, and continued growth of natural gas technology will impose additional demands on converter durability due to more severe operating conditions. For example, the exhaust temperature and relative humidity will be3 significantly higher for natural gas engines and result in higher stresses and fatigue than those for diesel engines.
The key objective of this paper is to review new advances in packaging design which have a great bearing on converter durability. Indeed, such advances have been instrumental in meeting the 100K mile durability requirement for automotive catalysts [5,6], while at the same time they have helped enhance the durability of motorcycle catalysts [7,8]. More recently, robust packaging designs have proven their effectiveness in close-coupled light-off applications with much more demanding operating conditions [9, 10 and 11].
Specifically, the paper will focus on substrate/washcoat interaction as it impacts the mechanical and thermal properties which, in turn, bear heavily on converter durability. Next, the variation of mount density and mounting pressure on ceramic substrate is examined as a function of canning technique. Such variation can have an adverse effect on both the mat integrity and substrate durability. Factors responsible for variation of mount density and ways to minimize it are discussed. Performance trade-offs associated with the cell geometry of diesel oxidation catalyst support are also addressed. Finally, the value of the axial push-out test on fresh and aged converters, as a quality control test, is demonstrated by examining changes in mounting pressure with aging. In this manner, packaging durability may be ascertained by requiring the push-out force to meet a certain minimum value even after aging.
CitationGulati, S., Sherwood, D., and Corn, S., "Robust Packaging System for Diesel/Natural Gas Oxidation Catalysts," SAE Technical Paper 960471, 1996, https://doi.org/10.4271/960471.
- Gulati, S.T. “Design Considerations for Diesel Flow-Through Converters,” SAE No. 920145 Detroit, MI February 1992
- Clerc, J.C. Miller, R.K. McDonald, A.C. Schlamadinger, H. “A Diesel Engine/Catalyst System for Pick-Up and Medium-Duty Trucks,” SAE No. 932982 Detroit, MI November 1993
- Miller, R.K. McDonald, A.C. Gulati, S.T. “Systems Design for Ceramic LFA Substrates for Diesel/Natural Gas Flow-Through Catalysts,” SAE No. 950150 Detroit, MI February 1995
- Barris, M.A. “Development of Diesel Exhaust Catalytic Converter Mufflers,” SAE No. 920369 Detroit, MI February 1992
- Stroom, P.D. Merry, R.P. Gulati. S.T. “Systems Approach to Packaging Design for Automotive Catalytic Converters,” SAE No. 900500 Detroit, MI February 1990
- Gulati, S.T. “New Developments in Catalytic Converter Durability,” CAPoC2 Conf. Proc. Brussels, Belgium September 1991
- Gulati, S.T. Ten Eyck, J.D. Lebold, A.R. “New Developments in Packaging of Ceramic Honeycomb Catalysts,” SAE No. 922252 San Francisco, CA October 1992
- Gulati, S.T. Ten Eyck, J.D. Lebold, A.R. “Durable Packaging Design for Cordierite Ceramic Catalysts for Motorcycle Application,” SAE No. 930161 Detroit, MI February 1993
- Locker, R.C. Schad, M.J. Sawyer, C.B. “Hot Vibration Durability of Ceramic Preconverters,” SAE No. 952414 Toronto, ON October 1995
- Socha, L. Locker, R.C. Gulati, S.T. Then, P.M. “Advances in Durability and Performance of Ceramic Preconverter System,” 8th Int'l Pacific Conf. on Automotive Engg. Yokohama, Japan November 1995
- Reddy, K.P. Helfinstine, J.D. Gulati, S.T. “New Tests for Characterizing the Durability of Ceramic Catalytic Converter Package,” SAE No. 960559 Detroit, MI February 1996
- Helfinstine, J.D. Gulati, S.T. “High Temperature Fatigue in Ceramic Honeycomb Catalyst Supports,” SAE No. 852100 Tulsa, OK October 1985
- Gulati, S.T. Summers, J.C. Linden, D.C. White, J.J. “Improvements in Converter Durability and Activity via Catalyst Formulation,” SAE No. 890796 Detroit, MI February 1989
- Gulati, S.T. Cooper, B.J. Hawker, P.N. Douglas, J.M. Winterborn, D “Optimization of Substrate/Washcoat Interaction for Improved Catalyst Durability,” SAE No. 910372 Detroit, MI February 1991
- Gulati, S.T. “Cell Design for Ceramic Monoliths for Catalytic Converter Application,” SAE No. 881685 Portland, OR October 1988
- Tech. Data Blue Sheet Bulletins B-132-Ed5-3M-887 and B-139-Ed5-5M-689-L/J Allegheny Ludlum Corporation Pittsburgh, PA 1989