A catalyst article and its use in an exhaust system for internal combustion engines is disclosed. The catalyst article comprises a substrate which is a wall-flow filter, a first catalyst composition, and a second catalyst composition. The first and second catalyst compositions each independently comprise an oxygen storage component (OSC) derived from a CeZr mixed oxide sol having a D90 of less than 1.3 micron and a particulate inorganic oxide having a D90 of from 1 to 20 microns.

A method for adapting modeled reaction kinetics of a reaction taking place in a catalytic converter, with model-based fill level feedback control. The method includes specifying a setpoint value for at least one fill level of at least one exhaust-gas component that can be stored in the catalytic converter; calculating at least one fill level of the catalytic converter using a signal of an exhaust-gas sensor upstream of the catalytic converter and using a catalytic converter model with at least one storage capacity and reaction kinetics of the at least one reaction taking place in the catalytic converter; setting an air-fuel mixture such that the calculated fill level approximates the specified setpoint value; ascertaining a difference between a signal of the exhaust-gas sensor upstream of the catalytic converter and a signal of an exhaust-gas sensor downstream of the catalytic converter; and deactivating the fill-level-dependent setting of the air-fuel mixture.

An exhaust purification system of an internal combustion engine includes a catalyst arranged in an exhaust passage of the internal combustion engine and able to store oxygen, a storage amount calculating part configured to calculate an oxygen storage amount of the catalyst, a poisoning amount calculating part configured to calculate a poisoning amount of the catalyst, and an oxygen amount control part configured to control an amount of oxygen supplied to the catalyst based on the oxygen storage amount and the poisoning amount.

A NO.sub.x absorber catalyst for treating an exhaust gas from a lean burn engine. The NO.sub.x absorber catalyst comprises a molecular sieve catalyst comprising a noble metal and a molecular sieve, wherein the molecular sieve contains the noble metal; an oxygen storage material for protecting the molecular sieve catalyst; and a substrate having an inlet end and an outlet end.

This disclosure is directed to catalyst compositions, catalytic articles for purifying exhaust gas emissions and methods of making and using the same. In particular, the disclosure relates to a catalytic article including a catalytic material on a substrate, wherein the catalytic material has a first layer and a second layer. The first layer provides effective lean NO.sub.x trap functionality and the second layer provides effective three-way conversion of carbon monoxide, hydrocarbons, and nitrogen oxides (NO.sub.x).

A substrate (11) includes an inflow-side cell (21), an outflow-side cell (22), and a porous, gas-permeable partition wall (23) that separates the inflow-side cell (21) and the outflow-side cell (22) from each other, and also includes a first catalyst portion (14) that is provided on a side of the partition wall (23) that faces the inflow-side cell (21) at least at a portion in upstream side in an exhaust gas flow direction, and a second catalyst portion (15) that is provided on a side of the partition wall that faces the outflow-side cell at least at a portion in downstream side. With respect to a pore volume of pores with a pore size of 10 to 18 μm, when a measured value of the pore volume in the first catalyst portion (14) and the partition wall (23) within a region where the first catalyst portion (14) is provided is defined as a first pore volume, and a measured value of the pore volume in the second catalyst portion (15) and the partition wall (23) within a region where the second catalyst portion (15) is provided is defined as a second pore volume, the first pore volume is greater than the second pore volume. A catalytically active component contained in the first catalyst portion (14) and a catalytically active component contained in the second catalyst portion (15) are of different types.

A catalyst system includes an oxygen storage and release material that has at least one compound of the structure YMO.sub.3+δ, where M is selected from Mn, Co, Cu, Ce, Ti, Ni, Zn, Fe and any combination thereof, and where δ is ≥0. The oxygen storage and release material is configured to allow absorption and release oxygen depending on the conditions of a reagent stream such that sufficient oxygen is maintained for the catalytic removal of at least one of incompletely combusted hydrocarbons, CO, and NO. The catalyst system is useful in a catalytic converter such that oxygen is supplied under rich combustion conditions in an engine upstream of the catalytic converter inlet and oxygen is adsorbed and absorbed under lean rich combustion conditions in the engine.

A three-way catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end, an outlet end with an axial length L; an inlet catalyst layer beginning at the inlet end and extending for less than the axial length L, wherein the inlet catalyst layer comprises an inlet palladium component; an outlet catalyst layer beginning at the outlet end and extending for less than the axial length L, wherein the outlet catalyst layer comprises an outlet rhodium component; and wherein the outlet catalyst layer overlaps with the inlet catalyst layer.

An exhaust gas purification system for vehicle includes: a housing disposed on an exhaust pipe to receive a exhaust gas discharged from an engine and to exhaust the exhaust gas passed rearward; a front end catalyst disposed in the housing to purify the exhaust gas flowing into the housing through a front end of the housing; a rear end catalyst disposed in the housing to purify the exhaust gas passing through the front end catalyst before the exhaust gas flows out to a rear end of the housing; and a controller connected to the exhaust pipe at a front end of the housing to control a concentration of unburned fuel contained in the exhaust gas flowing into the housing.

The present disclosure provides an exhaust gas purification catalyst having improved durability, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the downstream portion contains Rh fine particles, and wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation a of the particle size of 0.8 nm or less.