Disclosed are a hydrocarbon adsorption and desorption complex showing hydrocarbon adsorption and oxidation performance by controlling the cation ratio in zeolite, and a preparation method therefor. The hydrocarbon adsorption and desorption complex controls a cation ratio to exhibit the excellent hydrocarbon adsorption ability and oxidation performance even at a temperature lower than the catalyst activation temperature, and increases hydrothermal stability of the hydrocarbon adsorption and desorption complex through hydrothermal treatment to exhibit the excellent hydrocarbon adsorption and desorption performance even in a situation where water is present at a high temperature.

An exhaust system comprising: a NOx storage catalyst; an electric heating element; and a NOx reduction catalyst wherein the heating element is located downstream of the NOx storage catalyst.

An exhaust-gas purification system and method are provided for an internal combustion engine having an NOx storage catalytic converter and a downstream SCR catalytic converter. The NOx storage catalytic converter can be supplied in a first operating mode with an oxidizing exhaust gas and in a second operating mode with a reducing exhaust gas. A third operating mode is provided between the first operating mode and the second operating mode, in which an exhaust gas which has a lower content of oxidizing constituents than the first operating mode and a lower content of reducing constituents than the second operating mode can be supplied to the NOx storage catalytic converter to improve NH.sub.3 production at the start of converter regeneration.

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.

A method of regenerating a lean NOx trap (LNT) of an exhaust purification system provided with the LNT and a selective catalytic reduction (SCR) catalyst may include: determining whether a regeneration release condition of the LNT is satisfied; determining whether a regeneration demand condition of the LNT is satisfied; and performing regeneration of the LNT if the regeneration release condition of the LNT and the regeneration demand condition of the LNT are satisfied. In particular, the regeneration release condition of the LNT is satisfied if all of an engine operating condition, an LNT state condition, and a lambda sensor synchronization condition are satisfied.

A reductant insertion system for an after treatment system configured to decompose constituents of an exhaust gas, includes: a dry reductant tank configured to contain a dry reductant; a reductant delivery line configured to operatively couple the dry reductant tank to the after treatment system for delivery of the dry reductant to the after treatment system; and a pressurized gas source configured to communicate the dry reductant to the after treatment system through the reductant delivery line using pressurized gas.

An exhaust gas purification apparatus includes a three-way catalyst. The three-way catalyst includes a downstream catalyst layer and an upstream catalyst layer. The downstream catalyst layer is to be provided in an exhaust pipe. The downstream catalyst layer contains a noble metal material containing at least one of Pd, Rh, or Pt, and an OSC material containing at least ceria. The upstream catalyst layer is to be provided in the exhaust pipe closer to an engine than the downstream catalyst layer is. The upstream catalyst layer contains the noble metal material and the OSC material. The upstream catalyst layer contains the ceria at a content less than a content of the ceria in the downstream catalyst layer.

The present disclosure provides a method of making zeolite intergrowths. In one embodiment, the present disclosure provides a method of making an AEI-based material, including the steps of: preparing a mixture of water, an alumina source, a silica source, a CHA structure directing agent, and an AEI structure directing agent, wherein the molar ratio of the CHA structure directing agent to the AEI structure directing agent is from about 1:1 to about 1:15; heating the mixture at a temperature sufficient to promote formation of crystals; and calcining the crystals at a temperature of from about 450° C. to about 750° C. to obtain a product, wherein no halide-containing reagent is employed. The AEI-based materials of the present disclosure may find particular use in selective catalytic reduction of NO.sub.x in exhaust gas streams.

An exhaust system for treating an exhaust gas produced by a lean burn engine comprising: (i) a NO.sub.x absorber catalyst comprising a molecular sieve catalyst disposed on a substrate, wherein the molecular sieve catalyst comprises a noble metal and a molecular sieve, wherein the molecular sieve contains the noble metal; (ii) means for introducing hydrocarbons into the exhaust gas; and (iii) a lean NO.sub.x trap; wherein the NO.sub.x absorber catalyst is upstream of both the means for introducing hydrocarbons into the exhaust gas and the lean NO.sub.x trap.

Disclosed are a hydrocarbon adsorption and desorption complex showing hydrocarbon adsorption and oxidation performance by controlling the cation ratio in zeolite, and a preparation method therefor. The hydrocarbon adsorption and desorption complex controls a cation ratio to exhibit the excellent hydrocarbon adsorption ability and oxidation performance even at a temperature lower than the catalyst activation temperature, and increases hydrothermal stability of the hydrocarbon adsorption and desorption complex through hydrothermal treatment to exhibit the excellent hydrocarbon adsorption and desorption performance even in a situation where water is present at a high temperature.