A particulate filter (1) is provided having a first wall flow region (2) and a second flow through region (3). The filter is provided with a catalytic washcoat, whereby the filter can be used to remove both particulate matter and harmful gaseous emissions from an exhaust gas stream.

A motor vehicle emission control system includes a three zone catalytic converter component having a honeycomb support body with catalytically active coating having a precious metal content applied on the channel walls. The first coating zone extends in the longitudinal direction from the inlet-side end to a first coating boundary and has a first precious metal content. The second coating zone extends in the longitudinal direction from the first coating boundary to a second coating boundary situated downstream from the first coating boundary and has a second precious metal content that is lower than the first precious metal content. The third coating zone extends from the second coating boundary to the outlet-side end and has a third precious metal content that is lower than the second precious metal content. The coating has oxidation catalyst activity and is free of rhodium.

An exhaust muffler has an exhaust inlet, an exhaust outlet, as well as a catalytic converter which, in the flow direction, is disposed between the exhaust inlet and the exhaust outlet. The catalytic converter has at least one throughflow body which includes at least one wire body. At least one first component region of the throughflow body is coated with a catalytically functioning coating. The throughflow body moreover has a second component region which in terms of volume has a smaller quantity of catalytically functioning coating than the first component region.

A method for removing NO.sub.X from an oxygen-rich exhaust flow produced by a combustion source that is combusting a lean mixture of air and fuel may include passing the oxygen-rich exhaust flow through an exhaust aftertreatment system that includes a NO.sub.X oxidation catalyst that includes perovskite oxide particles, a NO.sub.X storage catalyst, and a NO.sub.X reduction catalyst.

Provided is a catalytic converter in which the entire catalyst constituting the catalytic converter can be efficiently utilized to purify exhaust gas, and the emission of hydrogen sulfide can be suppressed. A catalytic converter 10 includes catalyst layers 2A, 2B formed of a noble metal catalyst that are formed on cell wall surfaces of a substrate 1 having a cell structure in a longitudinal direction of the substrate 1 in which gas flows, in which the substrate 1 has a center region 1A having a relatively high cell density and a peripheral region 1B having a relatively low cell density, and lengths of the catalyst layers 2A, 2B of the center region 1A and the peripheral region 1B in the longitudinal direction are the same as each other, or the length of the catalyst layer 2B in the longitudinal direction is shorter than that of the catalyst layer 2A.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, a first treatment element positioned within the exhaust gas pathway, a first injector configured to introduce a first reductant into the exhaust gas pathway upstream of the first treatment element, a second injector configured to introduce a second reductant into the exhaust gas pathway downstream of the first treatment element, a second treatment element positioned within the exhaust gas pathway downstream of the second injector, the second treatment element including a SCR element, and a controller configured to periodically initiate a desulfuring regeneration cycle by increasing a concentration of hydrocarbons in the exhaust gas and increasing the flow of the first reductant through the first injector to oxidize sulfur contamination in the first treatment element at temperatures between 400 and 500 degrees Celsius.

An overall exhaust gas purification function based on an NOx reduction function and an HC oxidation function in an NSR catalyst arranged in an exhaust passage of an internal combustion engine is improved. In the NSR catalyst, a portion of an NOx storage catalyst layer supported by a carrier, which extends from its upstream end to an X % (0<X≦75) of an overall length thereof along the flow of exhaust gas, forms an upstream side catalyst layer, and a portion of the NOx storage catalyst layer at the downward side of the upstream side catalyst layer along the flow of exhaust gas forms a downstream side catalyst layer. The upstream side catalyst layer does not contain potassium (K) as an NOx storage material, but the downstream side catalyst layer contains potassium (K) as an NOx storage material.

An exhaust gas purification filter that is suitable for arrangement in an exhaust passage of an internal combustion engine and for collecting particulate matter contained in exhaust gas, comprises: exhaust gas inflow passages and exhaust gas outflow passages that are arranged alternately; and porous partitions that separate the exhaust gas inflow passages and the exhaust gas outflow passages from each other. Each of the partitions is divided into a coated zone in which a surface of a partition base is coated with a coating layer having a smaller average pore diameter than an average pore diameter of the partition base and a non-coated zone that is located on a downstream side of the coated zone and in which a surface of the partition base is not coated with the coating layer.

An exhaust gas purifying system includes: a NOx trapping agent (2) which adsorbs nitrogen oxide when an excess air ratio of exhaust gas is more than 1, and releases nitrogen oxide when the excess air ratio is 1 or less; a NOx purifying catalyst (13) which reduces nitrogen oxide to nitrogen; and an oxygen concentration controller which controls oxygen concentration in the exhaust gas. When the excess air ratio of the exhaust gas is more than 1, nitrogen oxide is adsorbed to the NOx trapping agent (2). When the excess air ratio of the exhaust gas is 1 or less, the oxygen concentration controller controls the oxygen concentration of the exhaust gas at an inlet of the NOx purifying catalyst between 0.8 and 1.5% by volume, so that the NOx purifying catalyst reduces nitrogen oxide released from the NOx trapping agent.

The present disclosure relates to an exhaust gas cleaning catalyst having a substrate and a catalyst coating layer coated on the substrate, in which the catalyst coating layer has an upstream-side coating layer formed from the upstream-side end portion of the exhaust gas cleaning catalyst in an exhaust gas flow direction and a downstream-side coating layer formed from the downstream-side end portion of the exhaust gas cleaning catalyst in the exhaust gas flow direction, when the upstream-side coating layer and the downstream-side coating layer overlap each other, the upstream-side coating layer is disposed on the downstream-side coating layer, and the upstream-side coating layer contains a catalytic metal and a ZrO.sub.2—CeO.sub.2 composite oxide in which Fe forms a solid solution.