Structural Analysis of Catalytic Converters in Automotive Exhaust Systems

This paper discusses many aspects of the structural analysis of catalytic converters on automotive exhaust systems. The analysis covers a canning process, where a substrate is wrapped with a mat material and canned with a steel shell; and a heating process, where high temperature exhaust gas passes through the substrate. In designing a catalytic converter, the maximum pressure on the substrate should not exceed the minimum isostatic strength of a chosen cell geometry of that substrate. At the same time, sufficient pressure is required to maintain a minimum retention force to hold the substrate in place. Also, lack of compression in the mat material, where the mat is in contact with exhaust gas, will cause mat erosion. Therefore, a careful investigation is needed to have the right amount of pressure on the substrate, both during canning and operation conditions, and at room and elevated temperatures. With the trend to use more thin wall substrates for better emission control, there is more need for this type of analysis.