Axial Characterization of Lightoff and Underfloor Catalytic Converters Vehicle-Aged on a 5.7 L Corvette 952416
Catalysts taken from the lightoff and underfloor converters of two 1986 Corvette exhaust systems which had been vehicle-aged for 100,000+ miles were cut into 1″ thick sections along their axis and characterized for lean lightoff and warmed-up performance using a laboratory reactor. Sections were then treated to remove the poisons, and the characterization was repeated. An axial gradient in both lightoff and warmed-up conversion efficiency for HC and CO was detected within the first 2″ of both lightoff converters for both vehicles. This activity gradient is in agreement with the gradient in the phosphorus and zinc concentrations found in the front 2-3″ sections of the lightoff converters. Comparison of these data sets with those obtained after removal of the P and Zn poisons led us to conclude that a significant part of the total deterioration of activity can be attributed to phosphorus and zinc poisoning for the front 1″ (and to a lesser extent for the second 1″ section) of the lightoff converters.
Citation: Beck, D., Monroe, D., DiMaggio, C., and Sommers, J., "Axial Characterization of Lightoff and Underfloor Catalytic Converters Vehicle-Aged on a 5.7 L Corvette," SAE Technical Paper 952416, 1995, https://doi.org/10.4271/952416. Download Citation
Donald D. Beck, David R. Monroe, Craig L. DiMaggio, John W. Sommers
General Motors NAO Research and Development Center
1995 SAE International Fall Fuels and Lubricants Meeting and Exhibition
Developments and Advances in Emission Control Technology-SP-1120, The Chevrolet Corvette-PT-118, SAE 1995 Transactions: Journal of Fuels and Lubricants-V104-4