Abstract: A method of reducing NOx in a vehicle exhaust operating by alternating exhaust flow between two lean NOx traps and directing the emerging exhaust to a downstream SCR catalyst system. While exhaust predominantly flows through one of the lean NOx traps, a reductant is provided to the other NOx trap so as to produce ammonia that is also directed to the SCR catalyst system. An exhaust system implementing the method of the invention is also provided.

Abstract: An exhaust treatment device for treating an exhaust gas stream combines the functionalities of a catalytic particulate filter and a NOx absorber catalyst into a single integral device and is disposed in an exhaust conduit. By combining the functionalities of the catalytic particulate filter and a NOx absorber catalyst into a single integral device, the exhaust treatment device eliminates the temperature losses inherent to the heat capacity of one catalytic device placed in front of the other.

Abstract: A process for controlling an exhaust system can comprise flowing exhaust gas from the engine past a first oxygen sensor, through a NOx adsorber, past a second oxygen sensor, through a catalyst and past a third oxygen sensor, wherein the first oxygen sensor, the second oxygen sensor, and the third oxygen sensor, are in operable communication with an electronic control module, and using a switching delay between the first oxygen sensor and the second oxygen sensor to determine a NOx value, wherein the NOx value is selected from the group consisting of a NOx regeneration time, a stored NOx amount, a NOx storage efficiency, and combinations comprising at least one of the foregoing NOx values. A desulfurization process can be initiated when the NOx value is less than or equal to a first selected value. During the desulfurization process, when the third oxygen sensor signals a condition rich of stoichiometry, oxygen can be provided to the catalyst.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: An exhaust treatment device for treating an exhaust gas stream combines the functionalities of a catalytic particulate filter and a NOx absorber catalyst into a single integral device and is disposed in an exhaust conduit. By combining the functionalities of the catalytic particulate filter and a NOx absorber catalyst into a single integral device, the exhaust treatment device eliminates the temperature losses inherent to the heat capacity of one catalytic device placed in front of the other.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: A NOx adsorber composition comprising a substrate; and a washcoat, wherein said washcoat comprises a catalytic metal component, a trapping material, and a porous support, wherein said porous support comprises cerium oxide and an oxygenated metal selected from the group consisting of lanthanum oxide, yttrium oxide, neodymium oxide, and combinations comprising at least one of the foregoing oxygenated metals.

Abstract: An exhaust gas catalyst system, comprising: a substrate; and a nitrogen oxides adsorber deposited on said substrate, the nitrogen oxides adsorber comprising: a porous support; and a material loaded on said porous support comprising: a NO oxidation catalyst, at least one alkali material, and at least one alkali metal barrier.

Abstract: A NOx adsorber catalyst system for treatment of gases in an exhaust discharge passage of an internal combustion engine comprising: a first adsorber catalyst supporting effective amounts of at least one noble metal component and a Ba component; and, a second adsorber catalyst supporting effective amounts of at least one noble metal catalyst, a Ba component, and a K component.

Abstract: A method and a system for extending useful life of a basic catalyst are disclosed. The basic catalyst comprises a particulate, porous, siliceous catalyst support and an alkali metal in the +1 oxidation state on the catalyst support surface. The catalyst is suitable for the synthesis of an alpha, beta-ethylenically unsaturated carboxylic acid by condensation of a saturated carboxylic acid with formaldehyde. The method of the present invention contemplates providing a reactor, or a series of reactors, containing the basic catalyst and a confined source of the alkali metal associated with a suitable carrier, upstream of the reactor or reactors. A feed stream to the reactor is passed first through the confined source and thereafter through the reactor while reaction conditions for the condensation reaction are maintained within the reactor. The temperature of the feed stream passing through the confined source can be modulated to control release of the alkali metal from the carrier.