Abstract: The present invention provides a thermally stable catalyst for treating automobile exhaust by-products is provided. The catalyst of the invention comprises a first section that includes a precious metal present in a first concentration and a second section that includes a precious metal present in a second concentration. The catalyst of the invention is characterized by a unique precious metal concentration profile in which the first concentration of the precious metal is lower than the second concentration of the precious metal. When placed with an automobile exhaust system, the second section is positioned downstream of the first section. The present invention also provides a lean NOx trap utilizing the unique precious metal concentration profile. The NOx trap is found to possess improved NOx conversion performance relative to a NOx trap with the same total amount of precious metal deposited uniformly over the volume of the trap.

Abstract: A method for remediating an emission containing NOx emissions includes introducing an exotherm generating agent into the NOx emissions when the inlet temperature of the NOx emissions is in a range of 300° C. to 600° C. and an air/fuel ratio is greater than or equal to 15; exposing the NOx emissions to a lean NOx trap; introducing a reducing agent into the emissions when the inlet temperature of the emissions is greater than 130° C. and less than 600° C.; exposing the NOx emissions having an air/fuel ratio greater than or equal to 15 to a selective catalytic reduction catalyst; and producing a remediated emission having an air/fuel ratio greater than or equal to 15.

Abstract: A method for remediating a NOx-containing lean diesel emission includes providing a LNT/SCR catalyst system including a SCR catalyst and a first and second LNT. The SCR catalyst is disposed downstream of the second LNT which is disposed downstream of the first LNT. The lean NOx-containing diesel emission is introduced to the first LNT with the NOx being absorbed on to the first LNT forming a substantially NOx-free lean diesel emission. An exotherm generating agent is introduced to the substantially NOx-free diesel emission between the first LNT and the second LNT to form a reactive lean diesel emission. The reactive lean diesel emission is introduced to the second LNT generating a quantity of heat effective for desorbing absorbed NOx. A reducing agent is introduced into the desorbed NOx between the second LNT and SCR catalyst. The desorbed NOx diesel emission is remediated in the SCR catalyst.

Abstract: The present invention provides a catalyst for use in a NOx trap that has reduced NOx release during rich purges, increased NO conversion efficiency under stoichiometric conditions, and improved sulfur tolerance. The catalyst of this embodiment includes a precious metal, an oxygen storage component in contact with the precious metal, and a NOx storage material. The oxygen storage component in contact with the precious metal is present in an amount that provides sufficient oxygen storage capacity to reduce the NOx release from the NOx trap during rich purges to less than 20% of the NOx that is stored in the NOx trap across the operating temperature window of the NOx trap, increase the NOx conversion efficiency under stoichiometric conditions to a value greater than 70%, and increase the sulfur tolerance of the NOx trap.

Abstract: In an apparatus having an internal combustion engine, a catalytic device for treating emissions from the engine, an upstream oxygen sensor positioned upstream of the catalytic device, a downstream oxygen sensor positioned downstream of the catalytic device, and a controller configured to determine a NOx storage capacity of the catalytic device from a difference between a signal received from the upstream oxygen sensor and a signal received from the downstream oxygen sensor, a method of operating the engine is disclosed, the method including operating the engine at a rich air/fuel ratio for a first interval; adjusting a temperature of the catalytic device to a diagnostic temperature for measuring an oxygen uptake by the catalytic device; operating the engine at a lean air/fuel ratio for a second interval; and adjusting the temperature of the catalytic device to an operating temperature.

Abstract: In an apparatus having an internal combustion engine, a method of operating the engine including operating the engine at a first non-stoichiometric relative air/fuel ratio for a first duration; operating the engine at a second non-stoichiometric relative air/fuel ratio for a second duration, wherein the second relative air/fuel ratio is on an opposite side of a stoichiometric relative air/fuel ratio as the first relative air/fuel ratio, and wherein the second duration is of sufficient length to allow at least one of one of a substantial saturation of oxygen storage sites in the catalytic device and a substantial regeneration of oxygen storage sites in the catalytic device; and operating the engine at a third non-stoichiometric relative air/fuel ratio for a third duration, wherein the third relative air/fuel ratio is on a same side of the stoichiometric relative air/fuel ratio as the second relative air/fuel ratio and is further from the stoichiometric relative air/fuel ratio than the second relative air/fuel

Abstract: A method for remediating an emission containing NOx emissions includes introducing an exotherm generating agent into the NOx emissions when the inlet temperature of the NOx emissions is in a range of 300° C. to 600° C. and an air/fuel ratio is greater than or equal to 15; exposing the NOx emissions to a lean NOx trap; introducing a reducing agent into the emissions when the inlet temperature of the emissions is greater than 130° C. and less than 600° C.; exposing the NOx emissions having an air/fuel ratio greater than or equal to 15 to a selective catalytic reduction catalyst; and producing a remediated emission having an air/fuel ratio greater than or equal to 15.

Abstract: A method of desulfating a catalytic NOx storage and conversion device is disclosed, wherein the method includes determining an amount of sulfur stored in the catalytic NOx storage and conversion device; determining an interval for exposing the catalytic NOx storage and conversion device to a rich exhaust stream based upon the determined amount of sulfur stored, wherein the interval is longer for lower amounts of sulfur stored and shorter for higher amounts of sulfur stored; and exposing the catalytic NOx storage and conversion device to the rich exhaust stream for the determined interval.

Abstract: The present invention provides a thermally stable catalyst for treating automobile exhaust by-products is provided. The catalyst of the invention comprises a first section that includes a precious metal present in a first concentration and a second section that includes a precious metal present in a second concentration. The catalyst of the invention is characterized by a unique precious metal concentration profile in which the first concentration of the precious metal is lower than the second concentration of the precious metal. When placed with an automobile exhaust system, the second section is positioned downstream of the first section. The present invention also provides a lean NOx trap utilizing the unique precious metal concentration profile. The NOx trap is found to possess improved NO storage capacity upon thermal aging relative to a NOx trap with the same total amount of precious metal deposited uniformly over the volume of the trap.

Abstract: A mechanical apparatus including a combustion engine, a conduit for transporting an exhaust stream away from the engine, a first catalytic NOx storage and conversion region disposed along the conduit, and a second catalytic NOx storage and conversion region disposed along the conduit at a location downstream from the first catalytic NOx storage and conversion region is disclosed. Each of the first catalytic NOx storage and conversion region and the second catalytic NOx storage and conversion region includes at least one catalytic metal configured to convert NOx to NO2 when the engine is supplied a lean air/fuel mixture, and at least one NOx adsorbing compound configured to adsorb NO2 for storage when the engine is supplied a lean air/fuel mixture, and wherein the one of the first and the second catalytic NOx storage and conversion regions has a lower concentration of catalytic metal than the other of the first and second catalytic NOx storage and conversion regions.

Abstract: A method of removing hydrogen sulfide from an emissions stream is disclosed, wherein the method includes directing the emissions stream into a hydrogen sulfide converter having a metal oxide catalyst, adsorbing the hydrogen sulfide in the emissions stream to the metal oxide catalyst in the hydrogen sulfide converter, reacting the hydrogen sulfide with at least one of an oxidant and a reductant in the hydrogen sulfide converter to chemically transform the hydrogen sulfide, and adjusting an air-fuel ratio of the emissions stream based on exhaust temperature of an emission control device, where said adjustment varies a duration of at least one of lean and rich operation to perform said adsorbing and reacting even as exhaust temperature varies.

Abstract: In an apparatus having a combustion engine and an emissions system including a catalytic converter and a metal oxide catalyst disposed downstream of the catalytic converter, a method of controlling a chemical transformation of hydrogen sulfide in an emissions stream to a less-noxious sulfur-containing compound is disclosed. The method includes reacting the hydrogen sulfide with the metal oxide catalyst to form a metal sulfide, monitoring a saturation of the metal oxide catalyst with the metal sulfide, and when a predetermined saturation of metal sulfide on the metal oxide is reached, changing an air/fuel ratio supplied to the combustion engine.

Abstract: The present invention provides a catalyst for use in a NOx trap that has reduced NOx release during rich purges, increased NO conversion efficiency under stoichiometric conditions, and improved sulfur tolerance. The catalyst of this embodiment includes a precious metal, an oxygen storage component in contact with the precious metal, and a NOx storage material. The oxygen storage component in contact with the precious metal is present in an amount that provides sufficient oxygen storage capacity to reduce the NOx release from the NOx trap during rich purges to less than 20% of the NOx that is stored in the NOx trap across the operating temperature window of the NOx trap, increase the NOx conversion efficiency under stoichiometric conditions to a value greater than 70%, and increase the sulfur tolerance of the NOx trap.

Abstract: The present invention discloses a method for reducing NOx in exhaust gases of an internal combustion engine. The purpose of this invention is to convert engine out NOx (approximately 90% NO in diesel exhaust) into roughly a 50:50 mixture of NO and NO2, while simultaneously oxidizing engine-out hydrocarbons which interfere with the reduction of NOx by urea or ammonia. The present invention demonstrates that a 50:50 blend of NO and NO2 is reduced more rapidly and with higher efficiency than a gas stream which is predominantly NO. In addition, catalyst in an engine exhaust that is a 50:50 mixture of NO and NO2 is far more resistant to hydrothermal deterioration than using NO alone. In another embodiment of the present invention, a vehicle exhaust system utilizing the method of the present invention is provided.