Three-Way Conversion Catalysts Part of the New Emission Control System 770365
When the three-way conversion (TWC) catalysts were aged on representative 1977 unleaded commercial fuel, they had higher conversion efficiencies and improved durability than catalysts aged on modified 1975 FTP specification fuel containing approximately 0.025 g/gal Pb and low levels of phosphorus. As the rhodium content was increased in a series of platinum-rhodium TWC catalysts, the maximum conversion efficiency and durability increased, and the mine recovery ratio of Pt/Rh was found to be most susceptible to lead poisoning. However, good NOx efficiencies can be obtained from mine recovery ratio Pt/Rh TWC catalysts after 25,000 miles of engine aging. It is shown that improvements in catalyst formulations containing mine recovery ratio Pt/Rh resulted in higher conversion efficiencies. Monolithic TWC catalysts require approximately the same total precious metal as current oxidation catalysts. Particulate TWC catalysts show beneficial effects in increasing the precious metal loading above 15 grams/cubic foot.
Citation: Mooney, J., Thompson, C., and Dettling, J., "Three-Way Conversion Catalysts Part of the New Emission Control System," SAE Technical Paper 770365, 1977, https://doi.org/10.4271/770365. Download Citation
Author(s):
J. J. Mooney, C. E. Thompson, J. C. Dettling
Affiliated:
Engelhard Industries Division Engelhard Minerals & Chemicals Corporation, Menlo Park, N. J. 08817
Pages: 11
Event:
1977 International Automotive Engineering Congress and Exposition
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
SAE 1977 Transactions-V86-A
Related Topics:
Three-way catalysts
Catalysts
Nitrogen oxides
Particulate matter (PM)
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