A Survey of Automotive Catalyst Technologies Using Rapid Aging Test Schedules Which Incorporate Engine Oil Derived Poisons

Automotive catalysts deactivate by thermal and poison mechanisms. Thermal degradation reduces catalyst efficiency by both agglomeration of precious metals and by reduction in surface area of the washcoat. Engine oil derived poisons degrade catalyst performance by coating the outer surface of the washcoat. Numerous catalyst technologies are aged using accelerated dynamometer aging schedules that simulate the thermal and poison degradation of field aged catalysts. Pd, Pd/Rh, Pt/Pd/Rh, and Pt/Rh catalyst technologies are aged and evaluated on various rapid aging test (RAT^sm) schedules in an effort to ascertain what catalyst technologies may be best for low temperature and high temperature applications. The performance of these catalyst technologies are evaluated on an air/fuel sweep test and a 3.8L auto-driver FTP stand. Results show that the RAT^sm schedule applies a phosphorus poison distribution (due to engine oil consumption) similar to vehicle aged catalysts.