Abstract: An internal combustion engine system includes a spark-ignited internal combustion engine powered by a gaseous fuel. The engine system also includes an air intake in air providing communication with the internal combustion engine. Further, the engine system includes an exhaust system in exhaust gas receiving communication with the internal combustion engine. The exhaust system includes a methane oxidation catalyst through which at least a portion of the exhaust gas flows and an exhaust gas recirculation line in exhaust gas providing communication with the air intake.

Abstract: Methods and systems include an operation to interpret a face-plugging index and/or a reduction in an expected oxidation efficiency of an oxidation catalyst disposed in an internal combustion engine aftertreatment system, and in response to the face-plugging index or the reduction oxidation efficiency reaching a threshold value, an operation to provide a catalyst element reversal command.

Abstract: System and methods for reducing secondary emissions in an exhaust stream from an internal combustion engine are disclosed. The systems and methods include a filtration device positioned downstream from an SCR catalyst of an aftertreatment system disposed in the exhaust system. The filtration device can also be used for particulate filter diagnostics and for treatment of ammonia slip.

Abstract: Systems and methods are disclosed that include an exhaust gas stream produced by an engine and an aftertreatment system including an SCR catalyst element receiving at least a portion of the exhaust gas stream. An exhaust outlet flow path has an inlet fluidly coupled to the exhaust gas stream at a position downstream of at least a portion of the SCR catalyst element that bypasses at least a portion of exhaust gas stream to provide for compositional measurement of the exhaust gas with a compositional sensor located downstream of a diagnostic catalyst positioned in the exhaust outlet flow path.

Abstract: One embodiment is a method including operating an SCR system at a plurality of commanded ammonia to NOx input ratios, providing a plurality of data indicating NOx output from the SCR system for the plurality of commanded ammonia to NOx input ratios, and evaluating the plurality of data to diagnose the SCR system. Additional embodiment are methods, systems, and apparatuses including SCR diagnostics. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Abstract: There is disclosed a method and system for pressurizing a reductant solution from a reductant storage device and superheating the pressurized reductant solution. The superheated pressurized reductant solution at least partially decomposes in the heat exchanger and/or a decomposition chamber before it is released into an exhaust system. The at least partially decomposed reductant solution is delivered to the exhaust system upstream of the SCR catalyst.

Abstract: A system and method includes an exhaust aftertreatment system for an internal combustion engine having a reductant stored in a solid storage media. The reductant is released by heating the solid storage media to convert the reductant to gaseous form. The system and method determines the quality of the solid storage media by measuring operating parameters of the aftertreatment system and comparing the operating parameters to expected parameters stored in a memory of a controller of the system.

Abstract: According to one embodiment, an exhaust gas after-treatment apparatus includes an exhaust tube through which a main exhaust gas stream is flowable. The exhaust tube defines an exhaust flow channel. The apparatus also includes an exhaust flow segregator positioned within the exhaust tube. The exhaust flow segregator separates the exhaust flow channel into a first channel through which a first portion of the main exhaust gas stream is flowable and a second channel through which a second portion of the main exhaust gas stream is flowable. Additionally, the apparatus includes an injector coupled to the exhaust tube. The injector is communicable in reductant injecting communication with the first portion of the main exhaust gas stream flowing through the first channel. The apparatus also includes at least one exhaust gas heater communicable in heat supplying communication with the first portion of the main exhaust gas stream flowing through the first channel.

Abstract: A technique is described including receiving a hydrocarbon stream, and heating the hydrocarbon stream with an exhaust steam from an internal combustion engine. This technique may include reacting the hydrocarbon stream catalytically to produce hydrogen and a modified hydrocarbon stream having a lower saturation state than the hydrocarbon stream, recovering energy from the hydrogen stream, and/or providing the modified hydrocarbon stream to a fuel supply for the internal combustion engine.

Abstract: An example method includes determining that a selective catalytic reduction (SCR) component having a zeolite-based catalyst is contaminated with platinum (Pt). The method further includes elevating the temperature of the SCR component to at least 600° C. in response to the determining the catalytic component is contaminated with Pt, and maintaining the elevated temperature of the catalytic component for a predetermined time period thereby restoring reduction activity of the catalyst.

Abstract: According to one representative embodiment, an apparatus for reducing NOx emissions in an engine exhaust gas stream of an engine system having a selective catalytic reduction (SCR) system with an SCR catalyst positioned downstream of a reductant injector includes a NOx reduction target module and a reductant module. The NOx reduction target module is configured to determine a NOx reduction requirement, which includes an amount of NOx in the exhaust gas stream to be reduced on the SCR catalyst. The reductant module is configured to determine the amount of reductant added to the exhaust gas stream to achieve the NOx reduction requirement. The amount of reductant added to the exhaust gas stream is a function of at least one ammonia storage characteristic of the SCR catalyst, at least one reductant-to-ammonia conversion characteristic, and a conversion capability of an AMOX catalyst in exhaust receiving communication with the SCR catalyst.

Abstract: An internal combustion engine including a two-stage turbocharger configuration is described. Located between the turbines of the two-stage turbocharger may be an oxidation catalyst and a passive NOx adsorber or an oxidation catalyst and an SCR device. An exhaust path extending from an engine body of the internal combustion engine to the second turbine of the two-stage turbocharger configuration may also include one or more hydrocarbon sources or one or more ammonia sources. A bypass valve arrangement may permit decreased flow through the first stage of the two-stage turbocharger arrangement as well as one or more of the elements positioned between the turbines of the two-stage turbocharger.

Abstract: A system and method for diagnosing operation of a NOx adsorber catalyst are disclosed. An operating temperature of the catalyst is monitored, and when it exceeds a catalyst desulfation temperature threshold that occurs when the catalyst undergoes a desulfation event, a control circuit determines an oxygen storage capacity of the catalyst as a function of at least an oxygen concentration of exhaust gas exiting the catalyst. The control circuit may further determine the oxygen storage capacity as a function of an oxygen concentration of exhaust gas entering the catalyst. The control circuit may further determine the oxygen storage capacity as a function of a mass flow rate of fresh air entering the internal combustion engine that produces the exhaust gas. The oxygen storage capacity may be mapped to catalyst aging information such as, for example, a remaining useful life of the catalyst.

Abstract: A method includes providing a system having a fluid flow, a fuel injector and an oxygen sensor disposed in the fluid flow, where the oxygen sensor is downstream of the fuel injector. The method includes determining a first air fuel ratio, changing an injection rate of the fuel injector and determining a second air fuel ratio, and determining a fault value for the fuel injector from the first air fuel ratio and the second air fuel ratio. The method further includes determining the fault value for the fuel injector by determining a difference between the first air fuel ratio and the second air fuel ratio, and by determining that the fault value is positive in response to the difference being lower than a passing threshold value. The method includes changing injection rates of the fuel injector for specified periods of time short enough to significant disruption of system temperatures.

Abstract: According to one representative embodiment, an apparatus for determining the degradation of a selective catalytic reduction (SCR) catalyst of an engine exhaust aftertreatment system includes a system properties module configured to store at least one system dynamics property value of the exhaust system at a first time and receive the at least one system dynamics property value of the exhaust aftertreatment system at a second time subsequent to the first time. The apparatus also includes a system dynamics module configured to determine a storage capacity of the SCR catalyst based on a comparison between the at least one system dynamic property value at the first time and the at least one system dynamic property value at the second time. Additionally, the apparatus includes an SCR catalyst degradation factor module configured to determine an SCR catalyst degradation factor based at least partially on the storage capacity of the SCR catalyst.

Abstract: An aftertreatment system including a method which provides a selective catalytic reduction (SCR) catalyst disposed in an exhaust stream of an engine; determines that an ammonia pre-load condition for the SCR catalyst is present; determines a first amount of ammonia pre-load in response to the ammonia pre-load condition; injects an amount of ammonia or urea into the exhaust stream in response to the first amount of ammonia; and adsorbs a second amount of ammonia onto the SCR catalyst in response to injecting an amount of ammonia or urea, where the second amount of ammonia is either the injected amount of ammonia or an amount of ammonia resulting from hydrolysis from the injected amount of urea.

Abstract: An exhaust aftertreatment process including providing a selective catalytic reduction (SCR) catalyst disposed in an exhaust stream of an internal combustion engine; determining that a temperature of the exhaust stream is not within an NH3 based SCR range; and providing an amount of unburned hydrocarbon (UHC) to the SCR catalyst in response to the temperature of the exhaust stream not being within an NH3 based SCR range.

Abstract: A system includes an internal combustion ignition engine with an exhaust gas flow, a particulate filter in the exhaust gas flow, a NOx reduction catalyst in the exhaust gas flow downstream of the particulate filter, a first oxygen sensor coupled to the exhaust gas flow downstream of the NOx reduction catalyst, and a second oxygen sensor coupled to the exhaust gas flow between the particulate filter and the NOx reduction catalyst. A controller includes an exhaust conditions module that interprets a first oxygen signal from the first oxygen sensor and a second oxygen signal from the second oxygen sensor and a combustion control module that commands a high engine-out air-fuel ratio when the first oxygen signal indicates a low oxygen content and commands a low engine-out air-fuel ratio when the first oxygen signal indicates a high oxygen content.

Abstract: A method includes determining whether selective catalytic reduction (SCR) test conditions are present, and in response to the SCR test conditions being present, operating an SCR aftertreatment system at a number of reduced ammonia to NOx ratio (ANR) operating points. The method further includes determining a deNOx efficiency value corresponding to each of the ANR operating points. The method further includes determining a reductant correction value in response to the deNOx efficiency values corresponding to each of the ANR operating points, and providing a reductant injection command in response to the reductant correction value.

Abstract: A method includes providing a system having a fluid flow, a fuel injector and an oxygen sensor disposed in the fluid flow, where the oxygen sensor is downstream of the fuel injector. The method includes determining a first air fuel ratio, changing an injection rate of the fuel injector and determining a second air fuel ratio, and determining a fault value for the fuel injector from the first air fuel ratio and the second air fuel ratio. The method further includes determining the fault value for the fuel injector by determining a difference between the first air fuel ratio and the second air fuel ratio, and by determining that the fault value is positive in response to the difference being lower than a passing threshold value. The method includes changing injection rates of the fuel injector for specified periods of time short enough to significant disruption of system temperatures.