Design Considerations for a Ceramic Preconverter System 940744

The preconverter is an essential element of exhaust gas treatment to help meet the tighter emission standards of TLEV and LEV levels. Its design must be chosen so as to meet the simultaneous requirements of compactness, faster light-off, low back pressure, high temperature durability and low cost. This paper presents design options for a ceramic substrate and durable package which lead to an optimum and cost-effective preconverter system. Preliminary data for high temperature physical durability of selected converter systems are presented. Performance parameters for light-off activity and back pressure are also computed and compared with those of standard substrates used in underbody application. Laboratory tests comprising of axial push-out test, high temperature vibration test, exhaust gas simulation test and the engine dynamometer test demonstrate the viability of ceramic preconverters for automotive application.