Subject of the invention is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: ⋅ a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), ⋅ wherein the platinum-group metal concentration (PGM) of the TWC2 is greater than the PGM of the GPF, wherein the PGM is determined in g/ft3 of the volume of the device. Also disclosed are methods in which the system is used and uses of the system.

Provided is an exhaust gas purification catalyst having an improved catalyst performance while securing an OSC in an air-fuel ratio (A/F) rich atmosphere where HC poisoning is likely to occur. The present disclosure relates to an exhaust gas purification catalyst including a substrate and a catalyst coating layer coated on the substrate. The catalyst coating layer has an upstream coat layer formed from an end portion in an upstream side with respect to an exhaust gas flow direction in the exhaust gas purification catalyst and a downstream coat layer formed from an end portion in a downstream side with respect to the exhaust gas flow direction in the exhaust gas purification catalyst. The downstream coat layer includes Rh as a catalytic metal, alumina-ceria-zirconia complex oxide, and alkaline earth metal.

An engine exhaust aftertreatment system having an organization and arrangement of certain selected components which achieve significant catalytic reduction of the known NOx pollutants (NO and NO.sub.2) in tailpipe-out exhaust, while also achieving significant catalytic reduction of sulfate pollutants in tailpipe-out exhaust.

A catalytic converter system having oxygen storage materials is disclosed and methods for determining whether to reactivate oxygen storage materials and monitoring failure events of the oxygen storage materials are also disclosed.

The present disclosure provides an exhaust gas purification catalyst having improved durability, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the downstream portion contains Rh fine particles, and wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation σ of the particle size of 0.8 nm or less.

An exhaust aftertreatment system for use with over-the-road vehicle is disclosed. The exhaust aftertreatment system includes a reducing agent mixer with a mixing can and a doser configured to inject heated and pressurized reducing agent into the mixing can for distribution throughout exhaust gases passed through the mixing can.

A catalyst article for treating a flow of a combustion exhaust gas comprises: a catalytically active substrate comprising one or more channels extending along an axial length thereof through which, in use, a combustion exhaust gas flows, the one or more channels having a first surface for contacting a flow of combustion exhaust gas; wherein the substrate is formed of an extruded vanadium-containing SCR catalyst material, wherein a first layer is disposed on at least a portion of the first surface, wherein the first layer comprises a washcoat of an ammonia slip catalyst composition comprising one or more platinum group metals supported on a particulate metal oxide support material, and wherein a layer comprising a washcoat of SCR catalyst composition is disposed on a surface in the one or more channels, wherein at least the portion of the first surface on which the first layer is disposed comprises a compound of copper, iron, cerium or zirconium or a mixture of any two or more thereof.

An exhaust emission control device has at least one exhaust gas line, at least one particulate filter and/or at least one exhaust gas catalytic converter connected to the exhaust gas line, and a heated catalyst assembly arranged upstream of the particulate filter and/or the exhaust gas catalytic converter. The heated catalyst assembly is designed to react fuel with exhaust gas, and has a housing provided with an inlet and an outlet connected to the exhaust gas line such that a partial flow of the exhaust gas flowing in the exhaust gas line can be fed through the inlet into the housing and can be discharged from the housing through the outlet back into the exhaust gas line downstream of the inlet. An exhaust emission control device of this type may be used in conjunction with an internal combustion engine, and may be used for emission control of exhaust gas.

Subject of the invention is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: ⋅ a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), ⋅ wherein the platinum-group metal concentration (PGM) of the TWC2 is greater than the PGM of the GPF, wherein the PGM is determined in g/ft3 of the volume of the device. Also disclosed are methods in which the system is used and uses of the system.

An internal combustion engine emissions reduction system in which a emissions passing through a second catalyst element having a second catalyst function are mixed with emissions passing through a first catalyst element having a first catalyst function.