Exhaust gas systems include an oxidation catalyst (OC) capable of receiving exhaust gas and oxidizing one or more of combustable hydrocarbons (HC) and one or more nitrogen oxide (NOx) species, a selective catalytic reduction device (SCR) disposed downstream from and in fluid communication with the OC via a conduit, and an electrically heated catalyst (EHC) disposed at least partially within the conduit downstream from the OC and upstream from the SCR. The EHC comprises a heating element having an outer surface including one or more second oxidation catalyst materials capable of oxidizing CO, HC, and one or more NOx species. The OC includes one or more storage materials individually or collectively capable of storing NOx and/or HC species. Exhaust gas can be supplied by an internal combustion engine which can optionally power a vehicle.

A layered emission control device for an engine system is provided, including a plurality of catalytic layers, the catalytic layers optionally or additionally comprising sublayers, each sublayer having a distinct composition. Advantages of such a device include providing increased treatment rates of one or more engine exhaust gas species over a wide range of engine exhaust operating conditions, while reducing exhaust emissions, and reducing a size of the emissions control system.

An exhaust system for a diesel engine comprises an oxidation catalyst for treating an exhaust gas from the diesel engine and an emissions control device, wherein the oxidation catalyst comprises: a first washcoat zone for oxidizing carbon monoxide (CO) and hydrocarbons (HCs), wherein the first washcoat zone comprises a first platinum group metal (PGM), which is a combination of platinum and palladium, a first support material and a hydrocarbon adsorbent material, which is a zeolite, and wherein the first washcoat zone does not comprise rhodium and is substantially free of manganese or an oxide thereof; a second washcoat zone for oxidizing nitric oxide (NO), wherein the second washcoat zone comprises platinum (Pt) and manganese (Mn) disposed or supported on a second support material, wherein the second support material comprises a refractory metal oxide, wherein the refractory metal oxide is silica-alumina or an alumina doped with silica in a total amount of 0.5 to 45% by weight of the alumina, and wherein the second washcoat zone does not comprise a hydrocarbon adsorbent material, which is a zeolite; and a substrate having and inlet end and an outlet end, and wherein the second washcoat zone is disposed at an outlet end of the substrate, and the first washcoat zone disposed at an inlet end of the substrate; and wherein the emissions control device is a selective catalytic reduction (SCR) catalyst, a selective catalytic reduction filter catalyst, a diesel particulate filter (DPF), or a catalyzed soot filter (CSF).

An oxidation catalyst for treating an exhaust gas from a diesel engine comprises: a first washcoat region for oxidising carbon monoxide (CO) and hydrocarbons (HCs), wherein the first washcoat region comprises a first platinum group metal (PGM) and a first support material, and wherein the first washcoat region does not comprise manganese or an oxide thereof; a second washcoat region for oxidising nitric oxide (NO), wherein the second washcoat region comprises platinum (Pt), manganese (Mn) and a second support material comprising a refractory metal oxide, which is silica-alumina or alumina doped with silica in a total amount of 0.5 to 45% by weight of the alumina, wherein the platinum (Pt) is disposed or supported on the second support material and the manganese (Mn) is disposed or supported on the second support material; and a substrate having an inlet end and an outlet end, and wherein the first washcoat region is a first washcoat layer and the second washcoat region is a second washcoat layer, and the second washcoat layer is disposed on the first washcoat layer; and wherein when the oxidation catalyst comprises a hydrocarbon adsorbent, which is a zeolite, then the first washcoat region further comprises the hydrocarbon adsorbent

An engine exhaust gas purification apparatus includes a three way catalyst disposed on an exhaust line, and which transforms harmful materials in exhaust gas to harmless materials by an oxidation-reduction reaction. The three way catalyst includes a first catalyst layer, a second catalyst layer, and a third catalyst layer laminated from an upper portion on a cordierite carrier, and the first catalyst layer comprises at least one platinum group metal and an oxygen non-storage material.

Hydrocarbon (HC) traps are disclosed. The HC trap may include a first zeolite material having an average pore diameter of at least 5.0 angstroms and configured to trap hydrocarbons from an exhaust stream and to release at least a portion of the trapped hydrocarbons at a temperature of at least 225 C. The HC trap may also include a second zeolite material having an average pore diameter of less than 5.0 angstroms or larger than 7.0 angstroms. One or both of the zeolite materials may include metal ions, such as transition, Group 1A, or platinum group metals. The HC trap may include two or more discrete layers of zeolite materials or the two or more zeolite materials may be mixed. The multiple zeolite HC trap may form coke molecules having a relatively low combustion temperature, such as below 500 C.

An oxidation catalyst may include hydrocarbon storage material. One implementation relates to a diesel oxidation catalyst that includes a catalyst having a front zone and a rear zone and a gradient of hydrocarbon storage material on the catalyst extending from the front zone to the rear zone. The gradient of hydrocarbon storage material, may comprise a linear gradient, a step gradient, a parabolic gradient, a logarithmic gradient, or other forms thereof.

An exhaust gas-purifying catalyst of the present invention comprises a substrate, and one or more catalytic layers provided on the substrate, wherein at least one of the catalytic layers (i) contains a precious metal, alumina, and an acidic oxide element, (ii) has a correlation coefficient .sub.Al,AE of 0.70 or more, and (iii) has a correlation coefficient .sub.PM,AE of 0.70 or more.

There is provided an exhaust purification apparatus for an internal combustion engine in which a catalyst capable of adsorbing and oxidizing hydrocarbon is provided in an exhaust pipe, the exhaust purification apparatus including temperature detection means for detecting a temperature of the catalyst, estimation means for accumulating a time during which the temperature of the catalyst detected by the temperature detection means is equal to or less than a predetermined temperature, and estimating an amount of hydrocarbon adsorbed on the catalyst from the accumulated time, and control means for controlling fuel ejection of the internal combustion engine in a first ejection mode in which the temperature of the catalyst is increased to a temperature where hydrocarbons adsorbed on the catalyst are oxidized, in a case in which the amount of hydrocarbons estimated by the estimation means exceeds a predetermined upper limit.

A porous ceramic honeycomb body including a substrate of intersecting porous walls forming axial channels extending from a first end face to a second end face. An active portion of the walls include a zeolite catalyst disposed inside pores thereof and/or is comprised of an extruded zeolite and a three way catalyst (TWC) is disposed on wall surfaces of at least a portion of the active portion.