Herein disclosed are compositions for passive NOx adsorption and oxidation that include at least a manganese-based oxide and one or more promoter materials and methods for making and using said compositions. The promotor materials may include a rare earth, transition, or main group metal. The compositions may be used in NOx emission control system and adsorbs NOx compounds at low temperatures and then release NOx at higher temperatures, where the NOx can be oxidized, without the hybridized MnOX composition breaking down. The compositions are capable of maintaining a sufficiently large surface area at high temperatures found in the emissions gas streams of internal combustion engines necessary for the complete elimination of NOx.

A nitrous oxide (N.sub.2O) removal catalyst composition for treating an exhaust stream of an internal combustion engine is provided, containing a platinum group metal (PGM) component on a metal oxide-based support, wherein the N.sub.2O removal catalyst composition is in a substantially reduced form, such that it has an oxygen deficiency of about 0.05 mmol oxygen atoms/g or greater, and wherein the N.sub.2O removal catalyst composition provides effective removal of at least a portion of N.sub.2O from the exhaust stream under lean conditions at a temperature of about 350 C. or lower. N.sub.2O removal catalytic articles, systems, and methods are also provided for removing at least a portion of N.sub.2O from an exhaust stream under lean, low temperature conditions.

Methods and systems are provided for an exhaust aftertreatment system. In one example, a system comprises an air injector positioned to inject air between a first catalyst and a second catalyst in response to an oxygen concentration of an exhaust gas falling below a threshold concentration while exhaust gas temperatures are less than a threshold temperature.

A nitrogen oxides (NO.sub.x) and hydrocarbon (HC) storage catalyst for treating an exhaust gas flow is provided. The NO.sub.x and HC storage catalyst includes (a) a zeolite, (b) noble metal atoms, and (c) a metal oxide, a non-metal oxide, or a combination thereof. One or more of the noble metal atoms is present in a complex with the metal oxide, the non-metal oxide or a combination thereof. The complex is dispersed within a cage of the zeolite. Methods of preparing the NO.sub.x and HC storage catalyst and methods of using the NO.sub.x and HC storage catalyst for treating an exhaust gas stream flowing from a vehicle internal combustion engine during a period following a cold-start of the engine are also provided.

Described are catalysts effective to abate NO.sub.x, hydrocarbons, and carbon monoxide from a gasoline engine exhaust gas. Such catalysts include a substrate having a first and second material disposed thereon, the first material effective to catalyze selective catalytic reduction of nitrogen oxides in the presence of ammonia and the second material effective to abate hydrocarbons and carbon monoxide, the first material comprising a molecular sieve promoted with copper and/or iron in a low loading, the second material comprising at least one oxide of Ni, Fe, Mn, Co, and Cu on a support selected from oxides of Ce, CeZr, Zr, Mn, Pr and combinations thereof. Also described are gasoline engine exhaust gas treatment systems and methods of treating exhaust gas from a gasoline engine.

The present disclosure is directed to a Low Temperature NOx-Absorber (LT-NA) catalyst composition which exhibits NOx adsorption in a broad temperature and space velocity range, and shifts NOx desorption to a desired temperature range. In particular, the LT-NA composition includes a large pore zeolite containing a palladium component and a small or medium pore zeolite containing a palladium component. Further provided is a catalyst article including the LT-NA catalyst composition, an emission treatment system for treating an exhaust gas including the catalyst article, and methods for reducing a NOx level in an exhaust gas stream using the catalyst article.

The present disclosure relates to ECU for an exhaust purging system comprises: a NOx catalyst provided in an exhaust passage; and a second composite sensor detecting an air-fuel ratio in a downstream of the NOx catalyst, the ECU, which performs a routine of a purge control, calculates the sum of values of the reductant that have been supplied to the NOx catalyst since the start of the routine of the purge control, determines whether the sum is greater than or equal to an end determination threshold, determines whether the air-fuel ratio is less than or equal to a predetermined value, and ends the routine of the purge control in response to an earlier one of a first affirmative determination that the sum is greater than or equal to the end determination threshold and a second affirmative determination that the air-fuel ratio is less than or equal to the predetermined value.

The present disclosure generally provides low-temperature nitrogen oxides (NO.sub.x) adsorbers used in the treatment of a NO.sub.x-containing exhaust gas stream and to methods of preparing and using the same. In particular, the NO.sub.x adsorber composition includes an active metal and a metal oxide support, wherein the metal oxide support includes greater than 50% by weight ceria based on the total weight of the NO.sub.x adsorber composition, and wherein the active metal includes about 0.01% to about 5% by weight ruthenium based on the total weight of the NO.sub.x adsorber composition.

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.

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.