New Catalyzed Cordierite Diesel Particulate Filters for Heavy Duty Engine Applications

A family of cordierite DPF filters were developed and studied for their efficacy for catalyzed soot filter applications. In addition to porosity and median pore size of DPF filters, breadth of pore size distribution, microstructure, and pore connectivity have a profound influence not only in filter performance (pressure drop, catalyst coatability, and filtration efficiency) but also on mechanical and physical properties. Through filter material composition development, optimum values for the %porosity, median pore diameter, and breadth of the pore size distribution for minimizing pressure drop have been identified, leading to the development of a new family of high-porosity cordierite diesel particulate filters that possess a unique combination of high filtration efficiency, high strength, and very low clean and soot-loaded pressure drop in both the catalyzed and non-catalyzed states. By controlling the microstructure, the impact of the catalyst on pressure drop has been minimized. Soot-loaded pressure drops of these new filters in their catalyzed state are less than 50% of other catalyzed commercial filters with the same cell geometry. In contrast, large pore size and high porosity filters raise concerns of low filtration efficiency and low mechanical strength at both catalyzed and uncatalyzed states. Addition of catalyst into the filters seems to have little or no impact on filter filtration efficiency, static mechanical and thermal properties.