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Packaging requirements to meet current and future exhaust legislations force automakers to use the given space either in the engine compartment or in underbody position as efficiently as possible. This requirement leads to substrate contours with wide ranges of different radii to fill the space with the recommended catalytic volume. Especially converters with race-track shaped substrates suffer from mechanical durability problems. They occure primarily in the region of the extreme wide radius due to erosion of the thermal expanding support mat. This is commonly known as mat erosion. A new approach to improve the durability of the substrate support system is a PatchWorkDesign support mat, which combines the advantages of an alternative fibre mat with those of the intumescent mat.

The “Multiple Disc Converter” is an innovative concept. In comparison to conventional catalytic converters, it is significantly less expensive and more compact, at identical conversion efficiency and durability. The catalytic substrate consists of 4 to 5 cylindrical ceramic discs with 62 cells/cm2 (400 cells/inch2). These are assembled in a sheet metal casing, without gaps between the discs, and angularly offset to each other. The flow through the channels is interrupted at the contact surfaces of the individual discs. Hence, the restarted turbulent flow intensifies the transverse mass transfer. Further, the uniformity of the exhaust gas flow is improved, particularly in the first discs. Thus, the conversion of emissions is improved and the durability extended. When the conversion is maintained at the level of conventional converters, then the converter volume can be substantially reduced using the same specific catalyst loading.