The technology disclosed herein provides a particulate filter that can appropriately avoid PM from passing toward the outlet cell and can exhibit an excellent PM capturing performance. The particulate filter 1 disclosed herein includes: an outercoat layer 20 provided on an inlet surface 16a of a partition 16 of a base material 10. The outercoat layer 20 at least includes: a lower layer 22 provided on the inlet surface 16a of the partition 16; and an upper layer 24 provided to cover the lower layer 22. The mean particle diameter of granules contained in the upper layer 24 is higher than the mean particle diameter of granules contained in the lower layer. The mean particle diameter of the granules in the lower layer 22 is from 0.4 m to 2.0 m inclusive, and the mean particle diameter of the granules in the upper layer 24 is from 2.0 m to 7.0 m inclusive. With such a configuration, PM can be captured in an inlet cell 12, thereby suitably avoiding PM from passing toward an outlet cell 14 and exhibiting an excellent PM capturing performance.

An exhaust gas post-processing system includes an oxidation catalyst configured to oxidize substances included in the exhaust gas; a diesel particulate filter configured to collect particulate matters included in the exhaust gas and disposed subsequent to the oxidation catalyst; a dosing module configured to inject a reducing agent and disposed subsequent to the diesel particulate filter; and a selective catalytic reduction configured to remove nitrogen oxide using the reducing agent included in the exhaust gas and disposed subsequent to the dosing module. The diesel particulate filter includes a catalytic component represented by La.sub.1-xAg.sub.xMnO.sub.3 (where 0<x<1).

Provided are emissions treatment systems for an exhaust stream having an ammonia-generating component, such as a NOx storage reduction (NSR) catalyst or a lean NOx trap (LNT) catalyst, and an SCR catalyst disposed downstream of the ammonia-generating catalyst. The SCR catalyst can be a molecular sieve having the CHA crystal structure, for example SSZ-13 or SAPO-34, which can be ion-exchanged with copper. The LNT can be layered, having an undercoat washcoat layer comprising a support material, at least one precious metal, and at least one NOx sorbent selected from the group consisting of alkaline earth elements, rare earth elements, and combinations thereof and a top washcoat layer comprising a support material, at least one precious metal, and ceria in particulate form, the top washcoat layer being substantially free of alkaline earth components. The emissions treatment system is advantageously used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines.

An exhaust system for an internal combustion engine comprises a lean NO.sub.x trap, a NO.sub.x storage and reduction zone on a wall flow monolithic substrate having a pre-coated porosity of 50% or greater, the NO.sub.x storage and reduction zone comprising a platinum group metal loaded on one or more first support, the or each first support comprising one or more alkaline earth metal compound, and a selective catalytic reduction zone on a monolithic substrate, the selective catalytic reduction zone comprising copper or iron loaded on a second support, the second support comprising a molecular sieve.

Provided is a system where a composite catalyst into which an LNT catalyst and an oxidation catalyst are combined, a catalyzed particulate filter, an injector configured to inject a urea water solution into an exhaust gas passage, and an SCR catalyst are arranged in this order in an upstream-to-downstream direction of the flow of the exhaust gas.

A catalyzed particulate filter may include at least one inlet channel extending in a longitudinal direction, and having a first end into which fluid flows and a second end which is blocked; at least one outlet channel extending in a longitudinal direction, and having a first end which is blocked and a second end through which the fluid flows out; at least one wall that defines the boundary between adjacent inlet and outlet channels and that extends in a longitudinal direction; and at least one support positioned within at least one of the at least one inlet channel and the at least one outlet channel.

An apparatus for purifying an exhaust gas includes an engine, an exhaust pipe, a first lean NOx trap (LNT) adapted to absorb nitrogen oxide (NOx) contained in the exhaust gas, to release the absorbed NOx, and to reduce the NOx contained in the exhaust gas or the released NOx or to generate ammonia (NH.sub.3), a second LNT adapted to absorb the NOx, to release the absorbed NOx, and to reduce the NOx contained in the exhaust gas or the released NOx or to generate the NH.sub.3, and a selective catalytic reduction (SCR) catalyst adapted to temporarily absorb the NH.sub.3 and to reduce the NOx contained in the exhaust gas, wherein the second LNT is positioned such that an average temperature of the second LNT is lower than that of the first LNT by 50-150 C. based on an average temperature of the exhaust gas.

An exhaust gas cleaning system for an internal combustion engine is provided with, in an exhaust passage of an internal combustion engine and in order from an upstream side: a hydrocarbon supply unit; an upstream side catalyst unit of an oxidation catalyst, a NOx reduction catalyst, or the like; and a catalyst-equipped fine particle collection filter having a hydrocarbon adsorption function, wherein when a vehicle on which the engine is mounted accelerates after driving for a preset set time period at a temperature of exhaust gas equal to or less than a preset set exhaust gas temperature, the supply of hydrocarbon into the exhaust gas is started when an exhaust gas temperature becomes equal to or more than a preset first set temperature, and the supply of hydrocarbon is terminated when a preset termination condition is satisfied.

Systems and methods to determine the pressure differential for selective catalytic reduction systems includes a first sensor coupled to an inlet of a selective catalytic reduction system, a second sensor coupled to an outlet of the selective catalytic reduction system, and a controller communicatively coupled to the selective catalytic reduction system. The controller is configured to interpret a first parameter indicative of a first pressure amount of the selective catalytic reduction system measured by the first sensor, interpret a secondary parameter indicative of a secondary pressure amount of the selective catalytic reduction system measured by the second sensor, determine a plurality of operating parameters based, at least in part, on the interpretation of the first parameter and the secondary parameter, and generate a selective catalytic reduction command based, at least in part, on the determination of the plurality of operating parameters.

Provided are emissions treatment systems for an exhaust stream having an ammonia-generating component, such as a NOx storage reduction (NSR) catalyst or a lean NOx trap (LNT) catalyst, and an SCR catalyst disposed downstream of the ammonia-generating catalyst. The SCR catalyst can be a molecular sieve having the CHA crystal structure, for example SSZ-13 or SAPO-34, which can be ion-exchanged with copper. The LNT can be layered, having an undercoat washcoat layer comprising a support material, at least one precious metal, and at least one NOx sorbent selected from the group consisting of alkaline earth elements, rare earth elements, and combinations thereof and a top washcoat layer comprising a support material, at least one precious metal, and ceria in particulate form, the top washcoat layer being substantially free of alkaline earth components. The emissions treatment system is advantageously used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines.