| 摘要 |
A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine comprises a porous substrate 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 catalytic surface washcoat layer comprising a plurality of solid particles, wherein the catalytic surface washcoat layer substantially covers surface pores of the porous structure, wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size provided by the catalytic surface washcoat layer, wherein the pores of the washcoated porous substrate are defined in part by spaces between the particles (interparticle pores) in the washcoat, wherein the second mean pore size is less than the first mean pore size and wherein the catalytic washcoat is a three-way catalyst comprising: platinum and rhodium; palladium and rhodium; or platinum, palladium and rhodium as active components supported on a high surface area oxide; and an oxygen storage component. |
