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A concern has been expressed regarding the durability of the ceramic thin wall and ultra-thin wall substrates under severe thermal and mechanical conditions. Damage that might result from these conditions would most likely lead to a reduction in catalyst performance. One of the potential damage mechanisms for automotive catalysts is erosion resulting from the impingement of particles onto the front face of the catalyst system. A basic study of the particulate erosion phenomenon of cellular ceramic substrates was undertaken in order to determine, in a controlled setting, the substrate, particulate, and flow conditions that might bring this damage about. This report will discuss a room temperature study of the effects of particle size, particle density, gas flow rate, cellular part orientation, and cellular design parameters on the erosion of ceramic substrates.

The light-off segment of the automotive Federal Test Procedure (FTP) cycle is receiving considerable attention because of the contribution this portion of the test makes to the overall emissions of the automobile, now that the emissions during the remainder of the cycle have been virtually eliminated. In order for the precious metal catalyst to react quickly to the temperature of the exhaust gas and reach conversion temperature as quickly as possible, the effects of all other heat sinks in the system need to be minimized. With the overall heat capacity of the system in mind, there have been several papers published in the past 10 years which analyze the heat capacity of parts of the catalyst system. Unfortunately, there are differences among the values for both specific and substrate heat capacity when all of these references are compared.