Gasoline engine emissions treatment systems having particulate filters

A catalyzed particulate filter located in an emission treatment system downstream of a gasoline direct injection engine for treatment of an exhaust stream comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates, the catalyzed particulate filter comprising:

• a three-way conversion (TWC) catalytic material that is coated onto or within a particulate filter in an amount in the range of 1.0 to 4 g/in3 (122 to 244 g/L);
• wherein the TWC catalytic material stores at least 100 mg/L of oxygen after a full useful life aging and comprises an oxygen storage component in an amount in the range of 1.0 to 4.0 g/in3 (122 g/L to 244 g/L);
• wherein the particulate filter comprises a pore size distribution such that a first set of pores has a first mean pore size of 30 μm or less and second set of pores has a second mean pore size of more than 30 μm;
• and
• wherein the TWC catalytic material comprises a particle size distribution such that a first set of particles has a first d90 particle size of 7.5 μm or less and a second set of particles has a second d90 particle size of more than 7.5 μm.

A method of treating an exhaust gas comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates, the method comprising:

• providing a catalyzed particulate filter comprising a three-way conversion (TWC) catalytic material coated onto or within a particulate filter in an amount of effective to provide a particulate emissions number of no more than 6×1011 per kilometer;
• locating the catalyzed particulate filter downstream of a gasoline direct injection engine;
• and
• contacting exhaust gas from the gasoline direct injection engine with the catalyzed particulate filter.

A method of making a catalyzed particulate filter, the method comprising:

• providing a particulate filter;
• providing a three-way conversion (TWC) catalytic material;
• and
• coating the TWC catalytic material onto or into the particulate filter in an amount of at least 1.0 g/in3 (61 g/L) to form the catalyzed particulate filter such that the catalyzed particulate filter has a coated porosity that is substantially the same as an uncoated porosity of the particulate filter.