Abstract: According to one embodiment of the present invention a selective reduction catalyst system with a broad temperature window for lean-burn gasoline and diesel engines is disclosed. The system includes a first and second zone, wherein the first zone is composed of an iron SCR catalyst and a second zone is composed of a copper SCR catalyst, and wherein the second zone is positioned downstream of the first zone. In another embodiment, a small copper SCR catalyst is placed in front of a second zone composed of an iron SCR catalyst and a third zone composed of a copper SCR catalyst, wherein the volume of the first copper SCR catalyst is a fraction of the volume of the second copper SCR catalyst. In yet another embodiment, a diverter valve would be included in the system to eliminate any NOx penalty produced by the front Cu SCR catalyst.

Abstract: According to at least one aspect of the present invention, there is provided an emission control system which includes a reductant injector injecting a pre-determined amount of a reductant into a vehicle exhaust passage, and sensors measuring an exhaust space velocity, a selective catalytic reduction (SCR) catalyst temperature, and a before-SCR nitrogen oxide (NOx) concentration, wherein the predetermined amount of the reductant is a function of the exhaust space velocity, the before-SCR NOx concentration, and the SCR catalyst temperature. In at least one particular embodiment, the predetermined amount of the reductant is measured according to equation (I) y=axn; wherein y is the flow of the reductant; x is the product of the exhaust space velocity and the before-SCR NOx concentration; and “a” and “n” are each independently a function of the catalytic temperature (“T”) of the selective catalytic reduction catalyst.

Abstract: An emissions-control system of a vehicle is provided, having an SCR device disposed downstream of an LNT in the exhaust. During an enrichment interval to purge the LNG, a duration of an enrichment subinterval beginning after a sensor indicates rich breakthrough is adjusted in response to an aging of the LNT. In this way, it is possible to modify LNT regeneration based on catalyst performance and thereby generate sufficient ammonia for improved operation of the SCR device.

Abstract: According to at least one aspect of the present invention, there is provided an emission control system which includes a reductant injector injecting a pre-determined amount of a reductant into a vehicle exhaust passage, and sensors measuring an exhaust space velocity, a selective catalytic reduction (SCR) catalyst temperature, and a before-SCR nitrogen oxide (NOx) concentration, wherein the predetermined amount of the reductant is a function of the exhaust space velocity, the before-SCR NOx concentration, and the SCR catalyst temperature. In at least one particular embodiment, the predetermined amount of the reductant is measured according to equation (I) y=axn; wherein y is the flow of the reductant; x is the product of the exhaust space velocity and the before-SCR NOx concentration; and “a” and “n” are each independently a function of the catalytic temperature (“T”) of the selective catalytic reduction catalyst.

Abstract: A method of controlling an engine having a lean NOx trap in the exhaust is described. The method comprises during a first mode, at a first temperature, storing NOx at a lean condition and then purging stored NOx from the NOx trap at a rich condition without concurrently supplying oxygen to the trap during the purging and during a second mode, at a second, lower temperature, storing NOx at a lean condition and then purging stored NOx from the NOx, where an exothermic reaction is generated to temporarily raise the temperature of the trap by supplying oxygen and reductants with an overall rich mixture to the trap during the purging.

Abstract: An emissions-control system of a vehicle is provided, having an LNT disposed in an exhaust system of the vehicle, downstream of the engine, an SCR device disposed downstream of the LNT, and a controller. The controller is operatively coupled to the engine and configured to cause the engine to provide a reducing exhaust to the LNT at least during an enrichment interval, the enrichment interval including an enrichment subinterval beginning after a sensor indicates rich breakthrough, and further configured to adjust the duration and/or the level of enrichment for the enrichment subinterval in response to an ageing of the LNT. In this way, it is possible to modify LNT regeneration based on catalyst performance and thereby generate sufficient ammonia for improved operation of the SCR device.

Abstract: The invention, in at least one embodiment, relates to a reverse platinum group metal zoned lean NOx trap system included in a vehicle and its method of use. One embodiment of the trap system is in a vehicle exhaust system operable during lean and rich periods. The trap system may include a first trap having a first substrate supporting a quantity of platinum and a second trap, positioned downstream of the first trap, and having a second substrate supporting a quantity of platinum and a quantity of rhodium. The total loading of platinum plus rhodium on the second trap is greater than or equal to the platinum on the first trap. In at least one embodiment, the second trap has a higher overall NOx conversion at a low temperature and the first trap has a higher overall NOx conversion at a high temperature.

Abstract: According to one embodiment of the present invention a selective reduction catalyst system with a broad temperature window for lean-burn gasoline and diesel engines is disclosed. The system includes a first and second zone, wherein the first zone is composed of an iron SCR catalyst and a second zone is composed of a copper SCR catalyst, and wherein the second zone is positioned downstream of the first zone. In another embodiment, a small copper SCR catalyst is placed in front of a second zone composed of an iron SCR catalyst and a third zone composed of a copper SCR catalyst, wherein the volume of the first copper SCR catalyst is a fraction of the volume of the second copper SCR catalyst. In yet another embodiment, a diverter valve would be included in the system to eliminate any NOx penalty produced by the front Cu SCR catalyst.

Abstract: Embodiments are described to improve the durability of a lean NOx aftertreatment system. According to one embodiment of the present invention an air injection system is used to inject air continuously into the exhaust system between the upstream three-way catalyst and the downstream selective catalytic reduction (SCR) catalyst when the engine is operating at stoichiometric or rich air/fuel ratios and the exhaust temperatures are above a calibratible level (e.g., 700° C.). In another embodiment, an oxidation catalyst is positioned downstream of the air injection point to prevent exothermic reactions from occurring on the SCR. In another embodiment, the reductant for the SCR is generated in-situ. In yet another embodiment, a diverter valve with a reduction catalyst in a bypass arm is utilized to bypass the SCR during high load conditions.

Abstract: A method of controlling an engine having a lean NOx trap in the exhaust is described. The method comprises during a first mode, at a first temperature, storing NOx at a lean condition and then purging stored NOx from the NOx trap at a rich condition without concurrently supplying oxygen to the trap during the purging and during a second mode, at a second, lower temperature, storing NOx at a lean condition and then purging stored NOx from the NOx, where an exothermic reaction is generated to temporarily raise the temperature of the trap by supplying oxygen and reductants with an overall rich mixture to the trap during the purging.

Abstract: The invention, in at least one embodiment, relates to a reverse platinum group metal zoned lean NOx trap system included in a vehicle and its method of use. One embodiment of the trap system is in a vehicle exhaust system operable during lean and rich periods. The trap system may include a first trap having a first substrate supporting a quantity of platinum and a second trap, positioned downstream of the first trap, and having a second substrate supporting a quantity of platinum and a quantity of rhodium. The total loading of platinum plus rhodium on the second trap is greater than or equal to the platinum on the first trap. In at least one embodiment, the second trap has a higher overall NOx conversion at a low temperature and the first trap has a higher overall NOx conversion at a high temperature.

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 catalyst system to provide emission reductions under lean and stoichiometric conditions. The catalyst system comprises a forward catalyst having a first cerium-free zone including oxides of aluminum, alkali metals and alkaline earth metals and precious metals and a second zone with a lower loading of precious metals, oxides of aluminum, alkali metals or alkaline earth metals. This forward catalyst stores NOx emissions under lean conditions for subsequent reduction and converts HC, CO and NOx during stoichiometric operation. The second downstream catalyst includes precious metals, reduces emissions under stoichiometric conditions, and stores any residual NOx emitted from the first catalyst for subsequent reduction. In another embodiment, a forward catalyst has top and bottom layers designed to reduce emissions under lean conditions. In this embodiment, a second downstream catalyst is used to reduce emissions under stoichiometric conditions.

Abstract: A hydrogen fueled reciprocating spark ignition engine includes a fuel system for providing gaseous hydrogen to the cylinders of the engine and a lean NOx trap coupled to the engine for treating the engine's exhaust. A controller determines when to purge the lean NOx trap and provides gaseous hydrogen to the lean NOx trap during purging by operating the engine fuel rich or injecting hydrogen upstream of the lean 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.

Abstract: A hydrogen fueled reciprocating spark ignition engine includes a fuel system for providing gaseous hydrogen to the cylinders of the engine and a lean NOx trap coupled to the engine for treating the engine's exhaust. An EGR system provides recirculated exhaust gas to the engine, and a controller operates the fuel system and EGR system during periodic purging of the lean NOx trap such that the engine is operated fuel rich, with the mass of EGR approximating 40%-80% of the mass of air and fuel.

Abstract: A hydrogen fueled reciprocating spark ignition engine includes a fuel system for providing gaseous hydrogen to the cylinders of the engine and a lean NOx trap coupled to the engine for treating the engine's exhaust. An EGR system provides recirculated exhaust gas to the engine, and a controller operates the fuel system and EGR system during periodic purging of the lean NOx trap such that the engine is operated fuel rich, with the mass of EGR approximating 40%-80% of the mass of air and fuel.

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 catalyst system to provide emission reductions under lean and stoichiometric conditions. The catalyst system comprises a forward catalyst having a first cerium-free zone including oxides of aluminum, alkali metals and alkaline earth metals and precious metals and a second zone with a lower loading of precious metals, oxides of aluminum, alkali metals or alkaline earth metals. This forward catalyst stores NOx emissions under lean conditions for subsequent reduction and converts HC, CO and NOx during stoichiometric operation. The second downstream catalyst includes precious metals, reduces emissions under stoichiometric conditions, and stores any residual NOx emitted from the first catalyst for subsequent reduction. In another embodiment, a forward catalyst has top and bottom layers designed to reduce emissions under lean conditions. In this embodiment, a second downstream catalyst is used to reduce emissions under stoichiometric conditions.

Abstract: A hydrogen fueled reciprocating spark ignition engine includes a fuel system for providing gaseous hydrogen to the cylinders of the engine and a lean NOx trap coupled to the engine for treating the engine's exhaust. An EGR system provides recirculated exhaust gas to the engine, and a controller operates the fuel system and EGR system during periodic purging of the lean NOx trap such that the engine is operated fuel rich, with the mass of EGR approximating 40%-80% of the mass of air and fuel.