An exhaust system according to an exemplary embodiment of the present invention includes a nitrogen oxide storing catalytic collector connected to an exhaust line and collecting a nitrogen oxide included an exhaust gas in a first temperature or less; a first selective catalytic reducer disposed at a rear portion of the nitrogen oxide storing catalytic collector and reducing a nitrogen oxide included in the exhaust gas; and a first urea injector disposed at the front side of the nitrogen oxide storing catalytic collector and supplying a urea solution when a temperature of the nitrogen oxide exceeds the first temperature.

System and methods are described for optimizing exhaust flow rate and temperature during specified operational periods warm-up and keep-warm conditions, by minimizing or maximizing heat flux during those specified operational periods.

When a catalyst temperature of a catalyst device is at or below a lower limit air-fuel ratio richness control is prohibited. When a first timing, where an estimated value of a NOx storage amount has reached an enrichment start threshold value, and a second timing, based on a set interval time in an enrichment interval time map, are both satisfied, the control is started. The second timing is corrected by multiplying the set interval time by an enrichment interval correction coefficient preset based on the catalyst temperature and a storage ratio of the estimated value of the NOx storage amount to an enrichment start threshold value of the NOx storage amount. The frequency of the air-fuel ratio richness control of a catalyst device configured to recover a purification capacity of a catalyst is reduced, and the catalyst temperature is raised while preventing white smoke development and hydrocarbon slip, to thereby achieve improvement in exhaust gas composition and improvement in fuel efficiency.

An exhaust system for treating an exhaust gas from an internal combustion engine is disclosed. The system comprises a modified lean NO.sub.x trap (LNT), a urea injection system, and an ammonia-selective catalytic reduction catalyst. The modified LNT comprises a first layer and a second layer. The first layer comprises a NO.sub.x adsorbent component and one or more platinum group metals. The second layer comprises a diesel oxidation catalyst zone and an NO oxidation zone. The diesel oxidation catalyst zone comprises a platinum group metal, a zeolite, and optionally an alkaline earth metal. The NO oxidation zone comprises a platinum group metal and a carrier. The modified LNT stores NO.sub.x at temperatures below about 200° C. and releases at temperatures above about 200° C. The modified LNT and a method of using the modified LNT are also disclosed.

A lean gasoline exhaust treatment catalyst article is provided, the article comprising a catalytic material applied on a substrate, wherein the catalytic material comprises a first composition and a second composition, wherein the first and second compositions are present in a layered or zoned configuration, the first composition comprising palladium impregnated onto a porous refractory metal oxide material and rhodium impregnated onto a porous refractory metal oxide material; and the second composition comprising platinum impregnated onto a porous refractory metal oxide material. Methods of making and using such catalyst articles and the associated compositions and systems employing such catalyst articles are also described.

A system includes a controller configured to perform an enable operation responsive to receiving information indicative of an enable parameter, the enable operation includes: determining a predicted downstream NOx value of an exhaust gas stream exiting a NOx storage catalyst; determining a downstream NOx value of the exhaust gas stream exiting the NOx storage catalyst; determining an error between the predicted downstream NOx value and the determined downstream NOx value; comparing the error to an error threshold; and determining that the NOx storage catalyst is in good health responsive to determining that the error does not exceed the error threshold. The controller is further configured to perform a disable operation responsive to receiving information indicative of a disable parameter, the disable operation causing a deactivation of at least a portion of the controller.

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.

An exhaust system for an internal combustion engine, the exhaust system comprising, a lean NO.sub.x trap, and a wall flow monolithic substrate having a pre-coated porosity of 40% or greater, and comprising an oxidation catalytic zone, the oxidation catalytic zone comprising a platinum group metal loaded on a first support, the first support comprising at least one inorganic oxide and a zinc compound.

An exhaust system for an internal combustion engine, the exhaust system comprising, a lean NO.sub.x trap (LNT), a wall flow monolithic substrate having a NO.sub.x storage and reduction zone thereon, the wall flow monolithic substrate having a pre-coated porosity of 40% or greater, the NO.sub.x storage and reduction zone comprising a platinum group metal loaded on a first support, the first support comprising one or more alkaline earth metal compounds, a mixed magnesium/aluminium oxide, cerium oxide, and at least one base metal oxide selected the group consisting of copper oxide, manganese oxide, iron oxide and zinc oxide.

The present subject matter relates to a method and a treatment system monitor for monitoring an engine exhaust after-treatment system containing more than one Lean NO.sub.x Traps (LNT). The method includes receiving an exhaust gas of a desired air-fuel ratio upstream of a respective LNT. The LNT is further regenerated using a richer than stoichiometric exhaust air-fuel ratio and subsequently an air-fuel ratio received downstream of the LNT is evaluated. Further, a working state of a respective LNT is determined based on the monitoring of the air-fuel ratio and oxygen level upstream and downstream of the LNT.