Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: An exhaust system for a vehicular positive ignition internal combustion engine comprises a filter for filtering particulate matter from exhaust gas emitted from the engine, which filter comprising a porous substrate having inlet 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 wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, which is less than the first mean pore size, and a three-way catalyst washcoat disposed on a separate substrate monolith located upstream of the filter, wherein a mass of three-way catalyst washcoat on the upstream substrate monolith is ?75% of the total mass of three-way catalyst washcoat in the exhaust system.

Abstract: An exhaust system for an internal combustion engine, which system comprises a monolith substrate (10) coated with a catalyst, which monolith substrate comprising a plurality of substantially parallel channels, each channel having a length extending from an upstream end to a downstream end; and a first sensor disposed in a hole (16) defined in part by an external wall of the monolith substrate, wherein the monolith substrate comprises a portion (12) of the plurality of channels wherein the catalyst composition in at least a part of the length of channels extending from the upstream end has an increased activity for a reaction for which the catalyst composition is intended relative to catalyst composition in a remainder (14) of the monolith substrate, the arrangement being such that the sensor is contacted substantially only with exhaust gas that has first contacted the catalyst composition having an increased activity.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: An exhaust system for a spark-ignited internal combustion engine comprises a three-way catalyst composition including an oxygen storage component, which TWC composition is coated on a flow-through monolith substrate, which substrate comprising a plurality of channels, each channel having a length extending from an inlet end to an outlet end and a single lambda sensor, wherein the substrate comprises a portion of the plurality of channels wherein the TWC composition in at least a part of the length of channels extending from the inlet end has a reduced oxygen storage activity, or no oxygen storage activity, relative to the TWC composition in a remainder of the substrate, the arrangement being such that the single lambda sensor is contacted substantially only with exhaust gas that has first contacted the TWC composition having a reduced oxygen storage activity or no oxygen storage activity.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: An exhaust system for a vehicular positive ignition internal combustion engine comprises a filter for filtering particulate matter from exhaust gas emitted from the engine, which filter comprising a porous substrate having inlet 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 wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, which is less than the first mean pore size, and a three-way catalyst washcoat disposed on a separate substrate monolith located upstream of the filter, wherein a mass of three-way catalyst washcoat on the upstream substrate monolith is ?75% of the total mass of three-way catalyst washcoat in the exhaust system.

Abstract: An exhaust system for an internal combustion engine, which system comprises a monolith substrate (10) coated with a catalyst, which monolith substrate comprising a plurality of substantially parallel channels, each channel having a length extending from an upstream end to a downstream end; and a first sensor disposed in a hole (16) defined in part by an external wall of the monolith substrate, wherein the monolith substrate comprises a portion (12) of the plurality of channels wherein the catalyst composition in at least a part of the length of channels extending from the upstream end has an increased activity for a reaction for which the catalyst composition is intended relative to catalyst composition in a remainder (14) of the monolith substrate, the arrangement being such that the sensor is contacted substantially only with exhaust gas that has first contacted the catalyst composition having an increased activity.

Abstract: A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine, which filter comprising 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 washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.

Abstract: An exhaust system for a spark-ignited internal combustion engine comprises a three-way catalyst composition including an oxygen storage component, which TWC composition is coated on a flow-through monolith substrate, which substrate comprising a plurality of channels, each channel having a length extending from an inlet end to an outlet end and a single lambda sensor, wherein the substrate comprises a portion of the plurality of channels wherein the TWC composition in at least a part of the length of channels extending from the inlet end has a reduced oxygen storage activity, or no oxygen storage activity, relative to the TWC composition in a remainder of the substrate, the arrangement being such that the single lambda sensor is contacted substantially only with exhaust gas that has first contacted the TWC composition having a reduced oxygen storage activity or no oxygen storage activity.