Gasoline engine emissions treatment systems having particulate traps

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

• locating an emissions treatment system downstream of a gasoline direct injection engine;
• providing a catalyzed particulate trap that comprises a three-way conversion (TWC) catalyst comprising an oxygen storage component deposited on a particulate trap in the emissions treatment system wherein an inlet side of the particulate trap comprises a layer of the three-way conversion catalyst thereon that has a thickness in the range of 10 to 50 microns;
• and contacting exhaust gas from the engine with the catalyzed particulate trap.

An emission treatment system downstream of a gasoline direct injection engine for treatment of an exhaust system comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates, the emission treatment system comprising a catalyzed particulate trap having an oxidation catalyst or a three-way conversion catalyst deposited thereon;

• one or more gas sensors, an on-board diagnostic (OBD) system;
• and further comprising a NOx trap, an SCR catalyst, or both located downstream of the catalyzed particulate trap.