Structured Foil Catalysts: A Road Map to Highly Effective, Compact Systems Aftertreatment

While emission standards are becoming more stringent with every new legislation level, the engineering of compact aftertreatment system is becoming extremely challenging. This paper outlines a road map for cost-effective, compact aftertreatment systems through use of catalysts with standard and structured foil substrates. The longitudinal-structure (LS) foil disrupts laminar flow regimes within channels enhancing mass transfer and gas reconditioning.

The presented results were applied to DOC catalyst functionality including parameters such as cross-section, substrate type and substrate volume.

The catalysts were degreend and tested on a production 15ltr ISX Cummins engine calibrated for US 1998 emissions. Various load points were selected to determine catalyst performance as a function of exhaust gas temperature, exhaust flow rate (space velocity) and exhaust gas composition. A HC injector system was used to characterize oxidation performance at various concentration levels.

The presented results show the trade-off between converter efficiency in mass transfer limited catalyst function and back pressure. The LS-Metalit showed superior performance with high potential for down sizing based on a high volumetric efficiency.