Abstract: A method of recovering selective catalytic reduction catalysts relates to metal-Zeolite based catalysts. A selective catalytic reduction catalyst service event where a metal-Zeolite based selective catalytic reduction catalyst of an exhaust aftertreatment system may perform below a threshold level of performance is determined. The selective catalytic reduction catalyst then exposed to a recovery fluid selected to facilitate movement of metal ions.

Abstract: Unique SCR catalyst including multiple washcoat formulations with differing performance characteristics are disclosed. One exemplary embodiment is an apparatus including a catalyst substrate defining a plurality of flow channels leading from an inlet to an outlet, a first washcoat composition distributed over a first portion of the flow channels, and a second washcoat composition distributed over a second portion of the flow channels. The first washcoat composition has a lower ammonia storage density than the second washcoat composition.

Abstract: An internal combustion engine system includes an engine and an aftertreatment system that is connected to the engine to receive an exhaust flow from the engine. The aftertreatment system includes a contaminant storage catalyst for storing contaminants produced by the engine during cold start and low temperature operating conditions, and a NOx reduction catalyst downstream of the storage catalyst for receiving the contaminants released from the storage catalyst when temperature conditions in the exhaust flow and/or NOx reduction catalyst are above an effective temperature threshold for NOx reduction. A contaminant amount stored on the storage catalyst can be estimated in response to one or more operating parameters to manage a storage capacity of the storage catalyst. A bypass can used to bypass the storage catalyst to preserve storage capacity for a subsequent cold start condition.

Abstract: A method and system for mitigating a urea deposit within an SCR system that includes determining a mass of an accumulated urea deposit present within the SCR catalyst and SCR piping, comparing the mass of the accumulated urea deposit with a deposit upper threshold limit, and initiating an SCR regeneration event when the mass of the accumulated urea deposit is greater than the deposit upper threshold limit. The method further includes determining an amount of NH3 passing through the SCR catalyst downstream of the urea deposit, comparing the amount of NH3 passing through the SCR catalyst with an NH3 regeneration threshold limit, and terminating the SCR regeneration event when the level of NH3 passing through the SCR catalyst is less than the SCR NH3 regeneration threshold.

Abstract: A method of recovering selective catalytic reduction catalysts relates to metal-Zeolite based catalysts. A selective catalytic reduction catalyst service event where a metal-Zeolite based selective catalytic reduction catalyst of an exhaust aftertreatment system may perform below a threshold level of performance is determined. The selective catalytic reduction catalyst then exposed to a recovery fluid selected to facilitate movement of metal ions.

Abstract: An exhaust aftertreatment system configured to reduce nitrous oxide (N2O) formation includes a first selective catalytic reduction (SCR) catalyst. The first SCR catalyst is configured for low N2O formation and low ammonia (NH3) storage capacity. A second SCR catalyst is positioned downstream of the first SCR catalyst. The second SCR catalyst is configured for high NH3 storage capacity.

Abstract: A system and method are disclosed for desulfating an oxidation catalyst in an aftertreatment system of a multifuel internal combustion engine. The oxidation catalyst can be desulfated in response to one or more desulfation triggering events. The desulfation process includes providing hydrocarbons from one or all of the multiple fuel sources to an upstream oxidation catalyst. The hydrocarbons react with the exhaust gas within the upstream oxidation catalyst to deplete oxygen in the exhaust flow to thereby reduce the desulfation temperature of the oxidation catalyst while elevating a temperature of the exhaust gas to a desulfation temperature range.

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: An apparatus includes a dosing module structured to suspend dosing in an exhaust aftertreatment system; a selective catalytic reduction (SCR) inlet NOx module structured to interpret SCR inlet NOx data and an SCR inlet temperature; a SCR outlet NOx module structured to interpret SCR outlet NOx data; and a system diagnostic module structured to determine an efficiency of a SCR system based on the SCR inlet and outlet NOx data over a range of SCR temperatures, wherein the system diagnostic module is further structured to determine a state of at least one of a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and the SCR system based on the SCR efficiency at an elevated SCR temperature range and the SCR efficiency at a relatively lower SCR temperature range relative to a high SCR efficiency threshold and a low SCR efficiency threshold.

Abstract: A method and system for mitigating a urea deposit within an SCR system that includes determining a mass of an accumulated urea deposit present within the SCR catalyst and SCR piping, comparing the mass of the accumulated urea deposit with a deposit upper threshold limit, and initiating an SCR regeneration event when the mass of the accumulated urea deposit is greater than the deposit upper threshold limit. The method further includes determining an amount of NH3 passing through the SCR catalyst downstream of the urea deposit, comparing the amount of NH3 passing through the SCR catalyst with an NH3 regeneration threshold limit, and terminating the SCR regeneration event when the level of NH3 passing through the SCR catalyst is less than the SCR NH3 regeneration threshold.

Abstract: An internal combustion engine system includes an engine and an aftertreatment system that is connected to the engine to receive an exhaust flow from the engine. The aftertreatment system includes a contaminant storage catalyst for storing contaminants produced by the engine during cold start and low temperature operating conditions, and a NOx reduction catalyst downstream of the storage catalyst for receiving the contaminants released from the storage catalyst when temperature conditions in the exhaust flow and/or NOx reduction catalyst are above an effective temperature threshold for NOx reduction. A contaminant amount stored on the storage catalyst can be estimated in response to one or more operating parameters to manage a storage capacity of the storage catalyst. A bypass can used to bypass the storage catalyst to preserve storage capacity for a subsequent cold start condition.

Abstract: There is disclosed method and systems for charging a depleted or spent solid storage media with gaseous ammonia.

Abstract: A method and system for mitigating a urea deposit within an SCR system that includes determining a mass of an accumulated urea deposit present within the SCR catalyst and SCR piping, comparing the mass of the accumulated urea deposit with a deposit upper threshold limit, and initiating an SCR regeneration event when the mass of the accumulated urea deposit is greater than the deposit upper threshold limit. The method further includes determining an amount of NH3 passing through the SCR catalyst downstream of the urea deposit, comparing the amount of NH3 passing through the SCR catalyst with an NH3 regeneration threshold limit, and terminating the SCR regeneration event when the level of NH3 passing through the SCR catalyst is less than the SCR NH3 regeneration threshold.

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: System, apparatus, and methods are disclosed for treating a reduction catalyst that has been exposed to an amount of sulfur. The treating of the reduction catalyst includes providing a fluid stream at a position upstream of the reduction catalyst. The fluid stream includes a temperature and a reductant amount, and the reductant amount includes an amount of urea, ammonia, or hydrocarbons.

Abstract: Unique SCR catalyst including multiple washcoat formulations with differing performance characteristics are disclosed. One exemplary embodiment is an apparatus including a catalyst substrate defining a plurality of flow channels leading from an inlet to an outlet, a first washcoat composition distributed over a first portion of the flow channels, and a second washcoat composition distributed over a second portion of the flow channels. The first washcoat composition has a lower ammonia storage density than the second washcoat composition.

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, methods, and apparatuses are provided for determining an SCR component sulfur value, determining whether the SCR component sulfur value exceeds a sulfur regeneration threshold and increasing an engine NO amount incident to an SCR catalyst in response to the SCR component sulfur value exceeding the sulfur regeneration threshold.

Abstract: Systems, apparatus and methods are disclosed for reducing the amount of nitrous oxide (N2O) produced in a selective catalytic reductant (SCR) catalyst in an exhaust aftertreatment system. The SCR catalysts are arranged to reduce the amount of N2O produced during NOx reduction while not adversely affecting NOx conversion.

Abstract: Systems and methods for managing aftertreatment systems that include passive NOx adsorption devices and SCR catalyst elements are disclosed. Temperature generation devices upstream of the passive NOx adsorption devices facilitate control of the aftertreatment systems to improve fuel economy and NOx conversion efficiency.