Materials Engineering and New Designs for Robust Cordierite Diesel Particulate Filters

The implementation of increasingly stringent emission regulations for diesel combustion engines necessitates the use of advanced after-treatment technologies. More specifically, ceramic wall flow filters are widely considered as the preferred approach to eliminate the particulate matter emitted by diesel engines. In addition to filtration efficiency, such a component must be able to accommodate catalysts, have a minimum impact on the overall system pressure drop and be durable for the life of the vehicle. In particular, it must be able to withstand the exothermic excursions occurring during regeneration of the filter, as the soot is burned away.

Based on its unique characteristic of refractoriness and high thermal shock resistance, Cordierite has been the material of choice for catalytic substrates for the last three decades. For the same reason, it has also been used as a Diesel Particulate Filter (DPF), especially for heavy-duty applications. Recent developments in the area of pore microstructure and filter design are described, which lead to further improvement of the performance of Cordierite as a DPF and make it even more attractive for such applications. Filter performance has been confirmed in various conditions, including laboratory and engine tests. Such test results are presented here.