Thermal Shock Resistance of Standard and Thin Wall Ceramic Catalysts 1999-01-0273
Thin wall ceramic catalysts offer improved performance by way of faster light-off, lower back pressure and higher FTP efficiency than standard ceramic catalysts. These advantages are attributed to their lower thermal mass, larger open frontal area and higher geometric surface area. This paper will focus on their physical durability, notably their thermal shock resistance.
The critical physical properties which influence thermal shock resistance - namely modulus of rupture, elastic modulus and coefficient of thermal expansion - will be examined over a wide range of operating temperatures for both standard (400/6.5) and thin wall catalyst supports (600/4.3 and 400/4.5) with stable high temperature washcoat systems. These data help evaluate the thermal shock capability of each system via computation of thermal shock parameter. The validity of such computations is tested against the thermal shock data from oven test. The agreement between thermal shock parameter and oven test data is found to be good. It shows that thin wall ceramic catalysts with high temperature compatible washcoat system possess more than adequate thermal shock resistance.