An exhaust system for a compression ignition engine comprising: a water adsorbent material; and a catalyst composition for treating an exhaust gas pollutant produced by the compression ignition engine; wherein the water adsorbent material is: (i) arranged to contact exhaust gas from the compression ignition engine before the catalyst composition; and (ii) in thermal communication with the catalyst composition.

A layered catalyst composite for the treatment of exhaust gas emissions, effective to provide lean NO.sub.x trap functionality and three-way conversion functionality is described. Layered catalyst composites can comprise catalytic material on a substrate, the catalytic material comprising at least two layers. The first layer comprising rare earth oxide-high surface area refractory metal oxide particles, an alkaline earth metal supported on the rare earth oxide-high surface area refractory metal oxide particles, and at least one first platinum group metal component supported on the rare earth oxide-high surface area refractory metal oxide particles. The second layer comprising a second platinum group metal component supported on a first oxygen storage component (OSC) and/or a first refractory metal oxide support and, optionally, a third platinum group metal supported on a second refractory metal oxide support or a second oxygen storage component.

An object of the present disclosure is to provide an exhaust gas purification catalyst device; an exhaust gas purification system; and a method for detecting deterioration of the above device.

The exhaust gas purification catalyst device includes a substrate, a first catalyst layer containing Pd and formed on the substrate, and a second catalyst layer formed on the first layer. Regarding the above device, ceria, Pd, and Rh are contained in a mixed state in the second layer; in the first and second layers, the total mass of ceria having a fluorite-type structure per 1 L volume of the substrate is 16.0 g or less; and in the second layer, the mass of Pd per 1 L volume of the substrate is 0.32 g or more.

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 exhaust gas purification catalytic device 1 contains Pt, Pd, and Rh as catalytic metals. The catalytic metal Pt is loaded on silica-alumina which serves as a support, and Pt-loaded silica-alumina obtained by loading the Pt on the silica-alumina is contained in a catalytic layer with which an exhaust gas contacts first.

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 oxidation catalyst composite for abatement of exhaust gas emissions from a lean burn engine is provided, the catalyst composite including a carrier substrate having a length, an inlet end and an outlet end, and an oxidation catalyst material coated on the carrier substrate. The oxidation catalyst material can include a first layer and a second layer. The first layer can include a first oxygen storage component that includes ceria and is impregnated with a palladium (Pd) component and a second component including one or more of magnesium (Mg), rhodium (Rh), and platinum (Pt). The second layer can include a refractory metal oxide component impregnated with platinum (Pt) and palladium (Pd), wherein the ratio of Pt to Pd is in the range of about 0:10 to about 10:0.

This exhaust gas purifying catalyst is provided with a substrate and a catalyst layer formed on a surface of the substrate. The catalyst layer contains zeolite particles that support a metal, and a rare earth element-containing compound that contains a rare earth element. The rare earth element-containing compound is added in such an amount that the molar ratio of the rare earth element relative to Si contained in the zeolite is 0.001 to 0.014 in terms of oxides.

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.