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This paper describes the experience gained during the successful development of a catalytic converter design for an in-line 4 cylinder application to meet the India 1998 cold start emissions standards. The vehicle application considered was an open loop carburetted system that met the 1997 hot start emission standards using a conventional Pt/Rh underbody mounted catalyst. The challenge was to meet the 1998 standards through catalyst changes and/or minor carburettor adjustments, thus providing the customer with the most cost-effective solution. The approach adopted was to use a mathematical computer simulation (MAESTRO™) developed by Delphi, that utilized engine out data obtained from emission testing of the vehicle to simulate proposed solutions. The biggest advantage of this approach was the ability to estimate the impact of system level changes on emissions performance thus enabling a quick optimization of the design variables.

The effects of oil derived poisons and thermal degradation on three-way automotive catalysts is investigated. Dynamometer rapid aging test (RATsm) schedules that incorporate both thermal and oil-derived poison degradation are used to age catalysts for FTP emissions studies. This paper presents three investigations. Vehicle aged converters are analyzed to determine the axial phosphorus distribution through out the catalyst. These phosphorus profiles are compared to dynamometer RATsm aged catalyst. Also, 27 converters were RATsm aged on three different RAT schedules at three different accelerated poison levels. The amount of phosphorus on the catalyst is compared to the amount of equivalent oil consumed by the aging engine. Finally, 24 converters were aged on three different RATsm schedules to determine the effects of catalyst volume, aging temperature and oil derived poisoning on FTP emissions using both Pd and Pt/Rh catalyst technologies.