Abstract: A chabazite (CHA) zeolite catalyst containing iron and copper is provided as an SCR catalyst for reducing nitrogen oxides (NOx) from vehicle engine exhausts. The catalyst is formed by incorporating iron during synthesis of the chabazite zeolite, followed by incorporating copper in an ion-exchange step. The resulting catalyst reduces nitrogen oxides over a wide range of temperatures from about 200° C. to about 700° C.

Abstract: The system and methods described provide for an Fe-SAPO-34 catalyst in an SCR catalyst for reducing nitrogen oxides (NOx) from vehicle engine exhausts. In one example, the catalyst is formed by incorporating iron during synthesis of the SAPO-34 zeolite, which allows iron to be incorporated into the zeolite crystal lattice structure and eliminates the post-synthesis ion-exchange step. The resulting Fe-SAPO-34 catalyst, which may be used in combination with or in addition to a Cu-CHA catalyst, exhibits good high temperature activity at temperatures above 550° C. and provides for a good thermal stability.

Abstract: An iron-zeolite chabazite (CHA) catalyst is provided as an SCR catalyst for reducing nitrogen oxides (NOx) from vehicle engine exhausts. The catalyst is formed by incorporating iron during synthesis of the chabazite zeolite, which eliminates the need for a post-synthesis ion-exchange step and which results in the incorporation of iron into the (CHA) zeolite crystal lattice structure. The resulting catalyst exhibits good high temperature activity at temperatures greater than 550° C. and exhibits good thermal stability.

Abstract: An exemplary emission treatment system for reducing gases from the exhaust of an engine includes an exhaust passage for transporting the exhaust from the engine. A selective catalytic reduction (SCR) catalyst is disposed within the passage, and an oxidation catalyst is disposed in the passage upstream of the SCR catalyst. The oxidation catalyst has noble metal, with at least 90 wt. % of the metal comprising palladium (Pd).

Abstract: A diesel exhaust aftertreatment system and method are provided. The system includes a lean NOx trap for reducing NOx and a transition metal-exchanged zeolite booster catalyst positioned downstream from the lean NOx trap for further reducing NOx. The lean NOx trap includes a NOx adsorbent material and one or more platinum group metals, and has a platinum group metal loading of less than about 90 g/ft3. The aftertreatment system provides high NOx conversion over a broad temperature range without the use of ammonia as a major reductant.

Abstract: The present invention relates to an emission treatment system for reducing gases from the exhaust of an engine. In at least one embodiment, the emission treatment system includes an exhaust passage for transporting the exhaust from the engine, a selective catalytic reduction (SCR) catalyst disposed within the passage, and an oxidation catalyst disposed in the passage upstream of the SCR catalyst, with the oxidation catalyst having metal, with at least 90 wt. % of the metal comprising palladium (Pd).

Abstract: A diesel exhaust aftertreatment system and method are provided. The system includes a lean NOx trap for reducing NOx and a transition metal-exchanged zeolite booster catalyst positioned downstream from the lean NOx trap for further reducing NOx. The lean NOx trap includes a NOx adsorbent material and one or more platinum group metals, and has a platinum group metal loading of less than about 90 g/ft3. The aftertreatment system provides high NOx conversion over a broad temperature range without the use of ammonia as a major reductant.

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.

Abstract: A method for improving NOx conversion efficiency of a urea base SCR catalyst is presented. Since efficiency is reduced by the presence of hydrocarbons in the catalyst, the method proposes to regenerate the SCR by maintaining its temperature above the boiling point of hydrocarbons for a sufficient period of time to free up catalyst storage sites. The regeneration process is followed by over-injection of ammonia to replenish the ammonia released from the SCR catalyst due to high regeneration temperatures.

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.

Abstract: A method for improving NOx conversion efficiency of a urea base SCR catalyst is presented. Since efficiency is reduced by the presence of hydrocarbons in the catalyst, the method proposes to regenerate the SCR by maintaining its temperature above the boiling point of hydrocarbons for a sufficient period of time to free up catalyst storage sites. The regeneration process is followed by over-injection of ammonia to replenish the ammonia released from the SCR catalyst due to high regeneration temperatures.

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.

Abstract: The invention is a method of treating exhaust gases generated by an internal combustion engine using a NOx trap in the exhaust gas system. The method comprises locating an essentially alkaline earth-free nitrogen oxide trap in the exhaust gas passage and cycling the air/fuel ratio of the exhaust gases entering the trap between lean and rich, such that the trap absorbs nitrogen oxides during the lean cycle and desorbs the nitrogen oxides when the concentration of the oxygen in the exhaust gas is lowered as during a rich cycle. The trap comprises: (a) a porous support material comprising mostly .gamma.-alumina and (b) metals consisting essentially of 0.1 to 2 wt. % tungsten oxide and precious metal comprising 0.5 to 4 wt. % platinum deposited on the support, the amount of said metals being individually based on the weight of said support material. The desorbed nitrogen oxides may be converted over the precious metal to N.sub.2 and O.sub.2 by reductants like hydrocarbons present in the exhaust gas.

Abstract: This invention is a sulfur-resistant, high surface area and temperature stabilized anatase crystal form of a mixed-oxide of titania and alumina comprising at least 40% molar amount titania. The mixed-oxide is made by co-hydrolysis of a mixture of the alkoxides of titanium and aluminum. The mixed oxide is useful as a catalyst support for treating exhaust gases generated by a diesel or gasoline internal combustion engine of automotive vehicles. The catalyst support may contain catalytic materials like precious metals.