An exhaust gas purification system for vehicle provided on an exhaust pipe connected to an exhaust side of an engine for purifying an exhaust gas of the engine includes a housing mounted on the exhaust pipe, a front end catalyst incorporated in the housing to primarily purify the exhaust gas flowing into the housing through the front end portion of the housing, a rear end catalyst incorporated in the housing to secondarily purify the exhaust gas passing through the front end catalyst before the exhaust gas flows out to the rear end portion of the housing, and a controller connected to the exhaust pipe at a front end portion of the housing to control the concentration of unburned fuel contained in the exhaust gas according to temperature of exhaust gas flowing into the housing and speed of the vehicle.

An NH.sub.3 supply amount controller reduces and adjusts a supply amount of NH.sub.3 to an SCR catalyst by an NH.sub.3 supplier, when an exhaust gas flowing into an NO.sub.X catalyst has a rich air-fuel ratio and NO.sub.X occluded by the NO.sub.X catalyst is reduced to N.sub.2. A reduction amount of the supply amount of the NH.sub.3 controlled by the NH.sub.3 supply amount controller is set smaller when a temperature of the NO.sub.X catalyst detected or estimated by an NO.sub.X catalyst temperature detector is higher.

A composition for exhaust gas purification including first alumina including alumina containing lanthanum and second alumina including alumina containing lanthanum. The first alumina has a higher lanthanum content than the second alumina. The second alumina has a larger particle size than the first alumina. The lanthanum content of the first alumina is preferably 2 to 12 mass %, in terms of oxide, based on the total mass of alumina and lanthanum oxide of the first alumina. The lanthanum content of the second alumina is preferably 9 mass % or less, in terms of oxide, based on the total mass of alumina and lanthanum oxide of the second alumina.

Example methods and systems for treating exhaust from an internal combustion engine may generally determine a catalytic converter in an exhaust system is at least partially deactivated by detecting an elevated exhaust temperature and a lean-burn operating condition. In response, a deactivation level of the catalytic converter may be determined, which may be compared with a threshold deactivation level. A magnitude of a temporary rich-fuel operating condition as a response may be determined based upon the comparison. The catalytic converter may be reactivated with the temporary rich-fuel operating condition.

Provided are a novel form of AFX zeolite, a novel synthesis technique for producing pure phase small pore zeolites, a novel synthesis method for producing a zeolite with an increased Al pair content, a catalyst comprising the AFX zeolite in combination with a metal, and methods of using the same.

Provided are a novel form of AEI zeolite, a novel synthesis technique for producing pure phase AEI zeolite, a catalyst comprising the AEI zeolite in combination with a metal, and methods of using the same.

Provided are a novel synthesis technique for producing pure phase aluminosilicate zeolite and a catalyst comprising the phase pure zeolite in combination with a metal, and methods of using the same.

Rich spike is carried out in an efficient manner. In an exhaust gas purification apparatus for an internal combustion engine which performs lean burn operation, the apparatus includes an NOx storage reduction catalyst, a controller to carry out rich spike, to calculate a storage amount of NOx, to calculate a storage amount of nitrates, and calculate a nitrate ratio, wherein the controller controls a timing at which the rich spike is carried out, based on the nitrate ratio.

An after treatment method for a lean-burn engine is disclosed. The after treatment method is configured to control an after treatment system sequentially equipped with an ammonia production catalyst module, a selective catalytic reduction (SCR) catalyst, and a CO clean-up catalyst (CUC) on an exhaust pipe through which an exhaust gas flows and which is connected to a lean-burn engine. NH.sub.3 generation in the ammonia production catalyst module is changed according to a temperature and a temperature change rate of the SCR catalyst.

Provided are catalyst articles, methods of manufacturing catalyst articles, and methods for controlling emissions in diesel engine exhaust streams with catalyst articles, where the emission treatment system of various embodiments effectively treats diesel engine exhaust with a catalyst article. In one or more embodiments, the catalyst articles have a platinum group metal end coating covering an outlet end surface of the catalytic article. In one or more embodiments, a method is provided where an applicator transfers a platinum group metal coating to an outlet end face of a catalytic article.