Effect of high temperatures on three-way automotive catalysts
The thermal deactivation of current automotive three-way catalysts (TWCs) was studied under various high temperature conditions to determine which were most damaging. The catalysts were aged on an engine dynamometer simulating the U.S. emission durability cycle with additional periodic exposure to high temperatures. The deactivation was measured as a function of the duration, temperature and air-fuel ratio during the high temperature exposure. With lean air-fuel ratios during the high temperature exposure, TWC performance as measured at 600/sup 0/F was most susceptible to deactivation showing appreciable loss of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx) conversions after 20 minutes of aging at 1600/sup 0/F. The TWC performance as measured at 800/sup 0/F had comparable loss only after 60 minutes of aging at 2200/sup 0/F. With rich air-fuel ratios the TWC performance remained nearly unaffected by aging up to 2000/sup 0/F. The results are explained in terms of the loss of active metal surface area and the rates of the various reactions involved in TWC operation.
- OSTI ID:
- 5603689
- Report Number(s):
- SAE-TP-840850
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
CARBON MONOXIDE
AIR POLLUTION MONITORING
CATALYTIC CONVERTERS
DEACTIVATION
TEMPERATURE EFFECTS
HYDROCARBONS
NITROGEN OXIDES
VEHICLES
AGING
CATALYSTS
CHEMICAL REACTION KINETICS
COMPARATIVE EVALUATIONS
DYNAMOMETERS
EXHAUST GASES
FUEL-AIR RATIO
HIGH TEMPERATURE
METALS
SERVICE LIFE
SIMULATION
SURFACE AREA
VERY HIGH TEMPERATURE
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
EQUIPMENT
FLUIDS
GASEOUS WASTES
GASES
KINETICS
MEASURING INSTRUMENTS
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL EQUIPMENT
REACTION KINETICS
SURFACE PROPERTIES
WASTES
330100* - Internal Combustion Engines
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)