Patent ID: 9352279
Filing Date: 2016-05-31
CPC Classification: B01D,B01J,F01N,F02B,Y02T

Claim Text:
1. A catalysed filter for filtering particulate matter from exhaust gas emitted from a positive ignition internal combustion engine, which filter comprising a porous substrate having a total substrate length and having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the porous substrate is coated with a three-way catalyst washcoat comprising a plurality of solid particles and at least one precious metal, wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, wherein the second mean pore size is less than the first mean pore size, which three-way catalyst washcoat being axially arranged on the porous substrate between a first zone comprising the inlet surfaces of a first substrate length less than the total substrate length and a second zone comprising the outlet surfaces of a second substrate length less than the total substrate length, wherein the sum of the substrate length in the first zone and the substrate length in the second zone ≧100% and wherein: (i) a washcoat loading in the first zone >second zone; (ii) a total precious metal loading in the first zone >second zone; or (iii) both a washcoat loading and a total precious metal loading in the first zone >second zone.