An exhaust purification system comprises an air-fuel ratio control device. If the air-fuel ratio detected by the downstream side air-fuel ratio sensor 41 reaches a second judged air-fuel ratio, the air-fuel ratio control device sets the target air-fuel ratio to a third set air-fuel ratio when the air-fuel ratio reaches the second judged air-fuel ratio, and switch the target air-fuel ratio from the third set air-fuel ratio to the second set air-fuel ratio when the air-fuel ratio becomes a value at the stoichiometric air-fuel ratio side from the second judged air-fuel ratio. The first set air-fuel ratio, the first judged air-fuel ratio and the second judged air-fuel ratio are an air-fuel ratio in the first region. The second set air-fuel ratio and the third set air-fuel ratio are an air-fuel ratio in a second region at an opposite side from the first region.

An oxygen storage material comprises a LaCoAl-based composite oxide containing lanthanum, cobalt and aluminum. The LaCoAl-based composite oxide is in a form in which at least part of the aluminum is solid-dissolved in a LaCo composite oxide having a perovskite structure, and has a composition expressed by the following chemical formula (1):
LaCo.sub.yAl.sub.xO.sub.(1)
where x and y are numbers satisfying conditions of 0<x <1 and 0<y<1, where x+y=0.5 to 1.5, and is a number of 1.5 to 4.5.

An oxygen storage material including a ceria-zirconia based composite oxide containing a composite oxide of ceria and zirconia, wherein the ceria-zirconia based composite oxide comprises at least one rare-earth element selected from the group consisting of lanthanum, yttrium, and neodymium, and an amount of the rare-earth element(s) contained in total is 1 to 10% by atom in terms of element relative to a total amount of cerium and zirconium in the ceria-zirconia based composite oxide, 60 to 85% by atom of the entire amount of the rare-earth element(s) is contained in a near-surface upper-layer region extending from a surface of each primary particle of the ceria-zirconia based composite oxide to a depth of 50 nm in the primary particle, and 15 to 40% by atom of the entire amount of the rare-earth element(s) is contained in a near-surface lower-layer region extending from a depth of 50 nm to a depth of 100 nm in the primary particle, a content ratio of cerium and zirconium in the ceria-zirconia based composite oxide is in a range of 40:60 to 60:40 in terms of an atomic ratio ([Ce]:[Z]), and the ceria-zirconia based composite oxide has an intensity ratio {I(14/29) value} between a diffraction line at 2=14.5 and a diffraction line at 2=29 which satisfies the following condition: I(14/29) value0.032,
where the intensity ratio {I(14/29) value} is determined from an X-ray diffraction pattern using CuK obtained by an X-ray diffraction measurement conducted after heating in air under a temperature condition of 1100 C. for 5 hours.

Methods and systems are provided for a multicomponent aftertreatment device arranged in a vehicle exhaust gas passage. In one example, a system may include an oxygen storage catalyst and an underbody trap catalyst comprising metal modified zeolite, the oxygen storage catalyst arranged upstream of the underbody trap catalyst in an exhaust passage of the vehicle.

An exhaust purification system of an internal combustion engine is provided with: an exhaust purification catalyst supporting a precious metal and able to store oxygen; and a control device controlling an amount of fuel fed to a combustion chamber. When a predetermined condition for performing a fuel cut operation stands, the control device is configured to perform fuel feed control in which fuel is temporarily fed to the combustion chamber so that the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst is a rich air-fuel ratio richer than the stoichiometric air-fuel ratio, then start fuel cut control stopping the feed of fuel to the combustion chamber in the state the internal combustion engine is operating.

An exhaust purification system of the internal combustion engine, is provided with: an exhaust purification catalyst having a catalytic function; a particulate filter arranged at a downstream side from the exhaust purification catalyst; an oxygen feed device feeding gas containing oxygen into exhaust gas flowing into the particulate filter; a detection device detecting a concentration of ammonia in exhaust gas flowing out from the particulate filter; and a control device. The control device controls the oxygen feed device so as to feed oxygen from the oxygen feed device to the particulate filter if a temperature of the exhaust purification catalyst is equal to or greater than an activation temperature and an air-fuel ratio of exhaust gas is a rich air-fuel ratio, and estimates the amount of deposition of particulate matter on the particulate filter based on the output of the detection device when feeding oxygen.

A catalyst oxygen purge control method may include a catalyst oxygen purge control method during a cold engine period of a catalyst oxygen purge control apparatus which includes a three way catalytic converter through which an exhaust gas combusted when air and fuel are mixed in a combustion chamber is exhausted and the exhaust gas passes, wherein the method includes determining whether a fuel cut condition of an injector which injects the fuel to the combustion chamber is satisfied, performing fuel cut of the injector when the fuel cut condition is satisfied, measuring an oxygen storage capacity of the three way catalyst, and adjusting an oxygen purge time based on the measured oxygen storage capacity.

Synergized platinum group metals (SPGM) with ultra-low PGM loadings employed as close-coupled (CC) three-way catalysts (TWC) systems with varied material compositions and configurations are disclosed. SPGM CC catalysts in which ZPGM compositions of binary or ternary spinel structures supported onto support oxides are coupled with commercialized PGM UF catalysts and tested under Federal Test Procedure FTP-75 within TGDI and PI engines. The performance of the TWC systems including SPGM CC (with ultra-low PGM loadings) catalyst and commercialized PGM UF catalyst is compared to the performance of commercialized PGM CC and PGM UF catalysts. The disclosed TWC systems indicate that SPGM CC TWC catalytic performance is comparable or even exceeds high PGM-based conventional TWC catalysts, with reduced tailpipe emissions.

A system includes an exhaust aftertreatment system including a particulate filter and a controller. The controller is configured to: receive a particulate filter regeneration event trigger; receive information, the information comprising a temperature regarding the particulate filter; determine the temperature regarding the particulate filter is below a temperature threshold associated with a particulate filter regeneration event; and responsive to determining the temperature regarding the particulate filter is below the temperature threshold, command the engine to operate in a cylinder deactivation mode, whereby at least one cylinder of a plurality of cylinders of the engine is deactivated.

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).