Ceramic Solution for Diesel Exhaust Aftertreatment

Extruded cordierite honeycomb substrates have proven successful both as filters for efficient trapping and incineration of soot carbon and as catalyst supports for the oxidation of CO and HC emissions in diesel exhaust. The microstructure, properties, and design of extruded cordierite ceramic filter (EX-80 composition) with 100/17 square cell structure, which help meet performance and durability requirements, are presented. Similarly, the design, properties, and washcoat compatibility of extruded cordierite ceramic catalyst support (EX-20 composition) with 300/8 square cell structure, which help meet conversion efficiency, back pressure and durability requirements are briefly reviewed. The importance of systems approach to filter design is illustrated by two different examples where the appropriate choice of filter composition, packaging design, soot loading and regeneration technique helps meet performance and durability requirements under specific operating conditions.