A vehicle engine aftertreatment system includes: a purification module including a plurality of aftertreatment devices having different characteristics, the aftertreatment devices being arranged in parallel; an upstream selection device provided at one side of the purification module for selectively supplying exhaust gas from an engine to one of the aftertreatment devices; and a downstream selection device provided at the other side of the purification module for discharging exhaust gas from one of the aftertreatment devices to out of the purification module.

A catalyst includes LTA zeolite including copper ions, wherein a Si/Al ratio of the LTA zeolite is 2 to 50. The catalyst is coated on a honeycomb carrier or a filter. The catalyst removes NOx from a reaction gas at 100° C. or above. The catalyst has an NOx conversion rate of 80% at 450° C. or above.

A multi-function catalyst article for treating both NO and carbon monoxide emissions in a flow of a combustion exhaust gas from a stationary emission source comprises a honeycomb monolith substrate comprising one or more channels which are open at both ends and extend along an axial length thereof and through which, in use, a combustion exhaust gas flows, which catalyst article comprising a catalyst composition comprising a combination of a first, vanadium-containing SCR catalyst component and a second component which is a compound of a transition metal comprising copper, manganese, cobalt, molybdenum, nickel or cerium or a mixture of any two or more thereof and optionally a third, crystalline molecular sieve component.

Systems, methods, and apparatus are contemplated in which a tube cell that produces a dielectric barrier discharge (DBD) is individually configured to minimize the mixing of unwanted byproducts of the generated plasma with an exhaust air stream. The tube cell generates a DBD within a tube cell, such that oxidants or radicals are generated in an environment substantially separated from the exhaust stream. The generated oxidants are directed to intersect with the exhaust stream to minimize the generation of unwanted byproducts. The tube cells are further shaped and arranged in tube cell arrays to alter the flow dynamics of the exhaust stream and the oxidant or radical streams, including mixing of the streams.

An exhaust gas purification filter has a honeycomb structure body and upstream side plug members. Cell holes are composed of inlet cell holes and outlet cell holes. In a central area and an outer peripheral area, a gas flow channel cross sectional area Sc1 of the outlet cell holes is larger than a gas flow channel cross sectional area So1 of the inlet cell holes, where Sc1<So1. A first ratio Rc is smaller than a second ratio Ro. The first ratio Rc is a ratio of Sc1 and Sc2. The second ratio Ro is a ratio of So1 to So2. In a first direction X and a second direction Y, the inlet cell holes and the outlet cell holes are alternately arranged, and the cell walls in the central area are larger in thickness than the cell walls in the outer peripheral area.

An exhaust emission control device for an engine is provided with a first purifying catalyst including an HC adsorbent that adsorbs HC at a low temperature and releases HC at a high temperature and a diesel oxidation catalyst capable of oxidizing HC, a second purifying catalyst including a NOx catalyst capable of storing NOx contained in exhaust, a NOx catalyst regenerator that regenerates the NOx catalyst while raising the temperature of the NOx catalyst, and HC controller that decides whether the amount of adsorbed HC that is HC adsorbed by the HC adsorbent is equal to or more than a preset reference amount and, when the amount of adsorbed HC is decided to be equal to or more than the reference amount, raises the temperature of the first purifying catalyst.

Internal combustion engine (ICE) exhaust gas treatment systems include the ICE having one or more cylinders configured to receive a mixture of air and fuel defined by an air to fuel ratio (AFR) for combustion therein, a control module configured to control the AFR, a diesel oxidation catalyst (DOC) configured to receive exhaust gas generated by the ICE and oxidize NOx species within the exhaust gas, and a selective catalytic reduction device (SCR) configured to receive exhaust gas from the DOC. Methods for operating and diagnosing such systems include determining, via the control module, a baseline value of a SCR performance parameter which is unsuitable, changing, via the control module, the AFR to change the DOC outlet NO2:NOx ratio, subsequently assessing a second value of the SCR performance parameter, and implementing a control action based on the second value of the SCR performance parameter.

The present disclosure generally provides low-temperature nitrogen oxides (NO.sub.x) adsorbers used in the treatment of a NO.sub.x-containing exhaust gas stream and to methods of preparing and using the same. In particular, the NO.sub.x adsorber composition includes an active metal and a metal oxide support, wherein the metal oxide support includes greater than 50% by weight ceria based on the total weight of the NO.sub.x adsorber composition, and wherein the active metal includes about 0.01% to about 5% by weight ruthenium based on the total weight of the NO.sub.x adsorber composition.

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 injector configured to selectively introduce a first reductant into the exhaust gas pathway in response to a sensed temperature of the exhaust gas being within a predetermined temperature range, and a first treatment element positioned within the exhaust gas pathway downstream of the first injector. The first treatment element includes a selective catalytic reduction (SCR) layer, a porous filter substrate, and a precious metal catalyst layer. The system also includes a second injector configured to introduce a second reductant into the exhaust gas pathway downstream of the first treatment element and a second treatment element positioned within the exhaust gas pathway downstream of the second injector. The second treatment element includes a SCR element.

The present disclosure provides the exhaust gas purification catalyst with the improved purification performance under the high Ga condition and the transient state in which an A/F repeats rich and lean phases. The present disclosure relates to an exhaust gas purification catalyst comprising a catalyst coating layer on a substrate, the catalyst coating layer containing a noble metal, a composite oxide containing cerium oxide and zirconium oxide, and a composite oxide containing aluminum oxide, wherein in the catalyst coating layer: an average thickness of the coating layer is in a range from 20 m to 100 m; a porosity measured by a weight-in-water method is in a range from 50% by volume to 80% by volume; and high-aspect-ratio pores having an aspect ratio of 5 or more account for 0.5% by volume to 50% by volume of a whole volume of voids, the high-aspect-ratio pore having an equivalent circle diameter in a range from 2 m to 50 m in a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction of the substrate and having an average aspect ratio in a range from 10 to 50, and wherein the noble metal is supported on peripheries of the voids, the composite oxide containing the cerium oxide and the zirconium oxide, and the composite oxide containing the aluminum oxide.