US Patent 7947102 Soot filter

An improved ceramic honeycomb filter has at least one porous partition wall defining a channel that is (1) microstructurally different along the length of the channel, (2) microstructurally different than at least a portion of a partition wall defining another channel or (3) combination thereof. The improved filter may be used for filtering Diesel exhaust and may have reduced back pressure and equivalent soot capture efficiency compared to a filter without having said microstructural differences.