Exhaust aftertreatment systems and methods for exhaust aftertreatment

Abstract

Exhaust aftertreatment system (100), comprising: an aftertreatment component (150; 250); an exhaust sensor (105) arranged downstream of the aftertreatment component; a container for active catalyst material (140;240), which is fluidly coupled to the aftertreatment component (150), and a controller (170) which is communicatively coupled to the outlet sensor (105) and the container for active catalyst material (140), wherein the controller (170) is configured to: evaluate an output signal from the outlet sensor (105) indicating performance of the aftertreatment component (150), determine whether the aftertreatment component (150) is deactivated, and in response to the determination that the aftertreatment component (150) is deactivated, activate the container for active catalyst material (140) such that a predetermined quantity of an active catalyst material is provided to at least one section of the aftertreatment component (150), wherein the active catalyst material coats at least the section of the aftertreatment component in order to restore the aftertreatment component (150).

Description

Cross-Reference to Related ApplicationsThis application claims priority to U.S. Provisional Patent Application No. 62 / 281,928, entitled "SYSTEMS AND METHODS FOR RECIRCULATING SELECTIVE CATALYTIC REDUCTION SYSTEMS" (SYSTEMS AND METHODS FOR RECOVERING SELECTIVE CATALYTIC REDUCTION SYSTEMS), filed Freiday, January 22, 2016, which is incorporated herein by reference in its entirety and for all purposes.Technical FieldThe present disclosure relates generally to exhaust aftertreatment systems for use with internal combustion (IC) engines.BackgroundExhaust aftertreatment systems are used to receive and treat exhaust gas generated by engines such as internal combustion engines. Conventional exhaust aftertreatment systems include any number of different components for reducing the fraction of harmful exhaust emissions in exhaust gas. For example, certain exhaust aftertreatment systems for diesel-powered internal combustion engines typically include catalytic oxidation and / or reduction components for degrading components of an exhaust gas from gasoline, natural gas, dual fuel, liquefied petroleum gas (LPG), ethanol, and / or biodiesel engines. For example, diesel engine aftertreatment systems may include three-way catalysts (TWCs), oxidation catalysts (e.g., a diesel oxidation catalyst (DOC)) for reducing CO and HC in the exhaust gas by oxidation processes, and / or a selective catalytic reduction system (SCR) including a catalyst formulated to convert NOx (NO and NO 2 at a particular level) to harmless nitrogen gas (N 2) and water vapor (H 2 O) in the presence of ammonia (NH 3). A reductant is often used in exhaust conduits that communicate the exhaust gas to the SCR system and / or other components of the aftertreatment system to facilitate, for example, decomposition of the NOx gases contained in the exhaust gas.A catalyst may also be included in one or more filters (e.g., a diesel particulate filter (DPF)) of the aftertreatment system. The filters may remove harmful particles and soot contained in the exhaust gas and also produce NO 2 for the SCR reaction. The catalyst contained in the particulate filter may be used for passive regeneration of the filter by catalyzing the decomposition (e.g., oxidation) of the particulates accumulated on the filter.The catalyst included in the SCR system or other aftertreatment components of the aftertreatment system (e.g., oxidation catalyst, TWC, catalyst on the filter, ammonia oxidation catalyst, etc.) may suffer performance degradation after multiple use. This results in a decrease in the catalytic conversion efficiency of the aftertreatment component, for example, by poisoning or other deactivation (e.g., by irreversible catalytic reactions, degradation, oxidation, reduction, etc.) after prolonged operation. The decrease in catalytic conversion efficiency may result in the amount of NOx gases emitted from the aftertreatment system increasing above the allowable limits, such as those set in emission standards. As soon as the performance of the catalyst of the aftertreatment component falls below acceptable values, the catalyst is generally replaced. Since catalysts are typically expensive, replacement of the catalyst adds significant cost to the maintenance of the aftertreatment system. The replacement of the catalyst also leads to interruptions of the operation of the plant with the aftertreatment system and thus to an additional cost load.The document DE 10 2009 037 585 A1 discloses a method for diagnosing the NOx conversion efficiency of an aftertreatment device using an adaptive on-board diagnostic algorithm.Summary of the InventionThe present invention is defined by the exhaust gas aftertreatment system according to the features of independent claim 1, the method according to the features of independent claim 11 and the method according to the features of independent claim 19.The embodiments described herein relate generally to systems and methods for recovering worn aftertreatment components, and more particularly to systems and methods for coating a deactivated catalyst included in an aftertreatment component with an active catalyst material to recover the aftertreatment component.In a first set of embodiments, an aftertreatment system includes an aftertreatment component. An outlet sensor is connected downstream of the aftertreatment component. A controller is communicatively connected to the outlet sensor. The controller is configured to interpret an output signal of the exhaust sensor. The output signal serves as an indicator of the performance of the aftertreatment component. The controller determines whether the aftertreatment component is deactivated. In response to determining that the aftertreatment component has been deactivated, the controller provides an active catalyst material to at least a portion of the aftertreatment component. The active catalyst material coats at least the portion of the aftertreatment component to restore the aftertreatment component.In another set of embodiments, a method includes providing an aftertreatment component of an aftertreatment system. The aftertreatment component contains a catalyst that has been used in the aftertreatment system. In response to an indication that the catalyst is deactivated, the catalyst is coated with a coating of an active catalyst material to restore the catalyst.It should be understood that all combinations of the foregoing concepts and other concepts discussed in greater detail below (provided that these concepts are not mutually incompatible) are intended to be part of the subject matter disclosed herein. In particular, all combinations of the claimed subject matter listed at the end of this disclosure are intended to be part of the subject matter disclosed herein.Brief Description of the DrawingsThe foregoing and other features of the present disclosure will become more apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Provided that these drawings illustrate only several embodiments in accordance with the disclosure and are therefore not to be considered as limiting the scope thereof, the disclosure will be described in more detail and detail using the accompanying drawings. FIG. 1 is a schematic illustration of an aftertreatment system according to an embodiment. FIG. 2 is a schematic block diagram of an embodiment of a control circuit that may be included in the aftertreatment system of FIG. 1. FIG. 3 is a schematic illustration of another embodiment of an aftertreatment system. FIG. 4 is a schematic flow diagram of a method for coating a catalyst contained in an SCR system by flowing through an active catalyst material. FIG. 5 is a schematic flow diagram of another embodiment of a method for coating an active catalyst material on a deactivated catalyst included in an aftertreatment component of an aftertreatment system to restore the catalyst. FIG. 6 panel A is a side view of a catalyst of an SCR system that has been in operation for some time; FIG. 6 panel B is an enlarged view of the catalyst of FIG. 6 panel A; FIG. 6 panel C is a side view of the catalyst of FIG. 6 panel A / B after coating with 10% active catalyst material; and FIG. 6 panel D is an enlarged view of the catalyst of FIG. 6 panel C; FIG. 6 panel E is a side view of the catalyst of FIG. 6 panel A / B after coating with 20% active catalyst material, and FIG. 6 panel F is an enlarged view of the catalyst of FIG. 6 panel E. FIG. 7 is a bar graph of NOx catalytic conversion efficiency at 220 and 550 degrees Celsius of a spent catalyst, the spent catalyst coated with 10% active catalyst material, the spent catalyst coated with 20% active catalyst material and a new catalyst, and their respective ammonia oxidation efficiency. FIG. 8 is a bar graph of ammonia storage capacity of the catalyst used, the catalyst used with 10% catalyst active material, the catalyst used with 20% catalyst active material, and the new catalyst of FIG. 7. FIG. 9 is a schematic block diagram of another embodiment of a computing device that may be used as the controller of FIGS. 1, 2, and / or 3.Throughout the following detailed description, reference is made to the accompanying drawings. In the drawings, like symbols typically identify similar components unless the context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other implementations may be utilized and other changes may be made without departing from the spirit or scope of the subject matter presented herein. It is understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, replaced, combined, and designed in many different configurations, all of which are expressly incorporated herein by reference.DETAILED DESCRIPTION OF VARIOUS EMBODIMENTSThe embodiments described herein relate generally to systems and methods for recovering worn aftertreatment components, and more particularly to systems and methods for coating a deactivated catalyst included in an aftertreatment component with an active catalyst material to recover the aftertreatment component.Various aftertreatment components in aftertreatment systems may include one or more catalysts formulated to decompose various constituents of an exhaust gas flowing through the aftertreatment system. Such aftertreatment components may be oxidation catalysts, ammonia oxidation catalysts, catalyzed particulate filters, and / or SCR systems. One or more catalysts may suffer performance losses after repeated use. This results in a decrease in the catalytic conversion efficiency of the aftertreatment component, for example, by poisoning or other deactivation (e.g., by irreversible catalytic reactions, degradation, oxidation, reduction, etc.) in field use.The decrease in catalytic conversion efficiency may ultimately result in deactivation of the aftertreatment component. For example, the decrease in catalytic conversion activity of the SCR system results in an increase in the NOx gases emitted from the aftertreatment system above the allowable limits, such as those set in the emissions standards. As soon as the performance of the catalyst of the SCR system (or another aftertreatment component described herein) falls below a reasonable level, the catalyst is typically replaced. Since catalysts are typically expensive, replacement of the catalyst adds significant cost to the maintenance of the aftertreatment system. The replacement of the catalyst also leads to interruptions of the operation of the plant with the aftertreatment system and thus to an additional cost load.Various embodiments of the systems and methods described herein for recovering at least a portion of an aftertreatment component may perform such as (1) enabling in situ coating of a catalyst of an aftertreatment component, such as an SCR system, with a predetermined amount of an active catalyst material, thereby increasing catalytic conversion efficiency of the aftertreatment component to a reasonable level; (2) enabling field recovery of the aftertreatment component without removing the aftertreatment component from the aftertreatment system, thereby reducing system downtime, and (3) extending the life of the catalyst included in the aftertreatment component, thereby reducing maintenance costs.FIG. 1 is a schematic illustration of an aftertreatment system 100, according to an embodiment. The aftertreatment system 100 may be fluidly coupled to an engine and configured to decompose constituents (e.g., carbon monoxide, unburned hydrocarbons, NOx gases, etc.) included in an exhaust gas generated by the engine. The engine may include an internal combustion engine that may be operated with diesel, gasoline, natural gas, biodiesel, ethanol, liquefied petroleum gas (LPG), or any other fuel source. The aftertreatment system 100 includes an aftertreatment component 150, a controller 170, and in some embodiments, a reductant storage tank 110, a reductant delivery component 120, a catalyst active material container 140.The aftertreatment system 100 is comprised of an inlet pipe 102 for receiving the exhaust gas (e.g., a diesel exhaust gas) of an engine (e.g., a diesel engine) and an outlet pipe 104 for draining the treated exhaust gas to the environment. A NOx inlet sensor 103 is located upstream of the aftertreatment component 150 near an inlet of the inlet pipe 102 and is configured to determine a NOx inlet amount of NOx gases including the exhaust gas entering the aftertreatment system 100. The aftertreatment component 150 is disposed between the inlet pipe 102 and the outlet pipe 104. An outlet sensor 105 is located behind the aftertreatment component 150, for example, in the outlet pipe 104, and generates an outlet signal indicative of performance (e.g., catalytic conversion efficiency) of the aftertreatment component 150. For example, the aftertreatment component 150 may include an SCR system and the exhaust sensor 105 may include an NOx exhaust sensor 105 configured to determine an exhaust NOx amount of NOx gases in the exhaust gas after passing through the SCR system 150. If the NOx outlet amount exceeds a predetermined threshold, this may indicate that the SCR system 150 (e.g., catalyst 154 included therein) is degraded or deactivated.As described herein, the terms "worn" or "deactivated" refer to an aftertreatment component 150 (e.g., the SCR system 150) operating below a predetermined power level. For example, an aftertreatment component 150 may be degraded or deactivated when a catalytic conversion efficiency of the aftertreatment component falls below a predetermined value, an exhaust gas flowing through the aftertreatment component 150 (e.g., the SCR system 150) includes an amount of constituents (e.g., NOx gases) that is greater than a maximum allowable amount (e.g., determined by various technical standards or emissions standards) and / or a temperature or pressure in the range of the aftertreatment component 150 is greater than or less than a predetermined threshold.In some embodiments, the NOx inlet sensor 103 may include a physical NOx sensor. In other embodiments, the NOx intake sensor 103 may include a virtual NOx sensor configured to determine the NOx intake amount based on one or more exhaust gas generating engine operating parameters (e.g., air-fuel ratio, compression ratio, combustion temperature, exhaust temperature, exhaust pressure, etc.). For example, the controller 170 may include models, look-up tables, algorithms, and / or equations for determining the NOx intake amount from the one or more operating parameters of the exhaust generating engine. Accordingly, in embodiments where the exhaust sensor 105 includes a NOx exhaust sensor, the NOx exhaust sensor 105 may also include a physical NOx sensor or a virtual NOx sensor for determining the NOx exhaust amount based on one or more engine parameters, the life of the SCR system 150, or another parameter.The aftertreatment component 150 includes a housing 152 defining an interior volume in which a catalyst 154 is located. Various non-limiting examples of aftertreatment component 150 that may be incorporated into aftertreatment system 100 include an SCR system, an oxidation catalyst, an ammonia oxidation catalyst, a catalyzed filter, or any other aftertreatment component that includes a catalyst. FIG. 1 shows aftertreatment system 100 having only a single aftertreatment component 150. In other embodiments, the aftertreatment system 100 may include any number of aftertreatment components in any arrangement, at least a portion of which includes a catalyst for decomposing various constituents (e.g., carbon monoxide, hydrocarbons, NOx gases, ammonia, etc.) of the exhaust gas flowing through the aftertreatment system 100.For example, the aftertreatment component 150 may include an SCR system 150. The SCR system 150 includes a housing 152 defining an interior volume in which a catalyst 154 is located. The housing 152 may be made of a rigid, heat-resistant, and corrosion-resistant material, e.g., stainless steel, iron, aluminum, metal, ceramic, or other suitable material. The housing 152 may have any suitable cross-section, e.g., round, square, rectangular, oval, elliptical, polygonal, or any other suitable shape.A reductant injection port 156 is located on a sidewall of the housing 152 that is configured to allow a reductant to be introduced into the interior volume defined by the housing 152. Reductant injection port 156 may be located upstream of catalyst 154 (e.g., to inject reductant or otherwise introduce reductant into the exhaust upstream of catalyst 154) or above catalyst 154 (e.g., to introduce reductant directly onto catalyst 154).A temperature sensor port 158 may also be provided on the housing 152, e.g., upstream of the catalyst 154. The temperature sensor terminal 158 is configured to receive a temperature sensor, e.g., a thermocouple, a thermistor, a resistance thermometer (RTD), or any other temperature sensor. The temperature sensor inserted into the temperature sensor connection 158 enables the determination of the inlet temperature of the exhaust gas entering the SCR system. In some embodiments, an outlet temperature sensor port (not shown) may also be provided on the housing 152. A second temperature sensor may be inserted into the outlet temperature sensor port so that an outlet temperature of the exhaust gas may be determined after passing the SCR system 150.The catalyst 154 of the SCR system 150 is configured to selectively decompose the constituents of the exhaust gas. Any suitable catalyst may be used, such as a platinum-, palladium-, rhodium-, cerium-, iron-, manganese-, copper-, vanadium-based catalyst, any other suitable catalyst, or a combination thereof. The catalyst may be disposed on a suitable substrate, such as a ceramic (e.g., cordierite) or metallic (e.g., Kanthal) monolith core, which may have a honeycomb structure, for example. A washcoat (interlayer) may also be used as a support material for the catalysts. Such washcoat materials may include, for example, alumina, titania, silica, any other suitable washcoat material, or a combination thereof. The exhaust (e.g., diesel exhaust) may flow over and around the catalyst such that any NOx gases trapped in the exhaust are further reduced to form an exhaust substantially free of carbon monoxide and NOx gases.The reducing agent storage tank 110 is configured to store a reducing agent. The reductant is formulated to facilitate the decomposition of the components of the exhaust gas (e.g., NOx gases contained in the exhaust gas). Any suitable reducing agent may be used. In some embodiments, the exhaust gas may comprise a diesel exhaust gas and the reductant comprises a diesel emission fluid.The diesel emission fluid may comprise urea, an aqueous urea solution, or any other ammonia-containing fluid, byproducts, or any other diesel emission fluids known in the art (e.g., the diesel emission fluid marketed under the name ADBLUE® ). The reducing agent may comprise, for example, an aqueous urea solution having a specific urea-water ratio. In certain embodiments, the reductant may include an aqueous urea solution including 32.5% by volume urea and 67.5% deionized water.A reducing agent supply member 120 is fluidly connected to the reducing agent storage tank 110. The reductant delivery component 120 is configured to selectively inject or otherwise employ the reductant into or prior to the SCR system 150 (e.g., the inlet pipe 102) or a mixer (not shown) disposed prior to the SCR system 150. The reductant delivery member 120 may include various structures to facilitate receiving the reductant from the reductant storage tank 110 and forwarding to the SCR system 150.The reductant delivery component 120 may include, for example, one or more pumps having filter screens (e.g., to prevent particulate matter of the reductant or contaminants from flowing through the pump) and / or valves (e.g., check valves) disposed upstream to receive the reductant from the reductant storage tank 110. In some embodiments, the pump may include a diaphragm pump, but any other suitable pump, such as a centrifugal pump, a suction pump, etc., may be used. The pump is configured to pressurize the reductant to supply the reductant to the SCR system 150 at a predetermined pressure. Screens, check valves, pulsation dampers, or other structures may also be disposed downstream of the pump to supply the reductant to the SCR system 150. In various embodiments, the reductant supply member 120 may also include a bypass line that provides a return of the reductant from the pump to the reductant storage tank 110.A valve (e.g., an open valve) may be provided in the bypass line. The valve may be configured to allow reductant to flow through to the reductant storage tank 110 if an operating pressure of the reductant generated by the pump exceeds a predetermined pressure to prevent over-pressure in the pump, reductant supply lines, or other components of the reductant delivery member 120 In some embodiments, the bypass line may be configured to allow reductant to return to the reductant storage tank 110 during the purging operation of the reductant delivery member 120 (e.g., after the aftertreatment system 100 has been shut down).In various embodiments, reductant delivery member 120 may also include a mixing chamber configured to receive pressurized reductant from a metering valve at a controllable rate. The mixing chamber may also be configured to receive air (or any other inert gas, e.g., nitrogen), for example, from an air supply unit, to communicate a combined flow of air and reductant to the SCR system 150 through the reductant injection port 156. In various embodiments, a nozzle may be disposed in the reductant injection port 156 and configured to direct a flow or jet of the reductant into the interior volume of the housing 152 of the SCR system 150.In various embodiments, the reductant delivery component 120 may also include a metering valve in the reductant delivery line for delivering the reductant from the reductant delivery component 120 to the SCR system 150. The metering valve may comprise any suitable valve, for example, a throttle valve, a gate valve, a check valve (e.g., a tilting check valve, a pivoting check valve, an axial check valve, etc.), a ball valve, a spring loaded valve, an air assisted injector, a solenoid valve, or any other suitable valve. The metering valve may be selectively opened to deliver a predetermined amount of reductant into the SCR system 150, or upstream thereof, at a predetermined time.The active catalyst material container 140 may be included in the aftertreatment system 100 or may be separate from the aftertreatment system 100. The catalyst active material container 140 is configured to contain a catalyst active material. The catalyst active material may be the same as catalyst 154 or another catalyst active material and may include, for example, platinum, palladium, rhodium, cerium, iron, manganese, copper, vanadium-based catalyst, any other suitable catalyst active material corresponding to the catalyst of aftertreatment component 150, or a combination thereof. In some embodiments, the active catalyst material in the active catalyst material container 140 may be provided with a washcoat that serves as a support material for the active catalyst material. Such washcoat materials may include, for example, alumina, titania, silica, any other suitable washcoat material, or a combination thereof.In some embodiments, the catalyst active material container 140 is configured to contain a solution or suspension of the catalyst active material. For example, the active catalyst material may be dissolved or suspended in a suitable medium, e.g., water or solvents such as methanol, ethanol, acetone, etc., to form a solution or suspension of the active catalyst material. The active catalyst material container 140 is configured to be coupled to the aftertreatment component 150 (e.g., the SCR system 150) to route the active catalyst material to the aftertreatment component 150 when needed.In some embodiments, aftertreatment component 150 is recovered offline, i.e., after decoupling and removing from aftertreatment system 100. In such embodiments, the active catalyst material container 140, which may be separate from the aftertreatment system 100, is fluidly coupled to the aftertreatment component 150. The active catalyst material container 140 is activated so that the active catalyst material is dispensed into the interior volume of the housing 152. The catalyst active material coats the catalyst 154, for example, in an amount ranging from 0-100 wt %, including all ranges and values therebetween, thereby restoring the catalyst 154.In other embodiments, the active catalyst material container 140 is included in the aftertreatment system 100 and is fluidly coupled to the aftertreatment component 150. The active catalyst material container 140 is configured such that the active catalyst material is forwarded to the aftertreatment component 150 for a certain amount of time as needed while the aftertreatment component 150 is online, i.e., still coupled to the aftertreatment system 100. The active catalyst material container 140 may be fluidly coupled to the aftertreatment component 150 via existing openings or ports on the housing 152 of the aftertreatment component 150. Such ports may be, for example, temperature sensor ports (e.g., temperature sensor port 158), pressure sensor ports, NOx sensor ports, a reductant injection port (e.g., reductant injection port 156), or any other suitable opening in housing 152. In this way, the catalyst 154 may be coated with the active catalyst material without removing the catalyst 154 from the housing 152 of the aftertreatment component 150.The active catalyst material may be applied to each portion of the catalyst 154 in any suitable configuration. For example, the active catalyst material may be layered on the catalyst 154. In other embodiments, the active catalyst material may be deposited on a portion or portion of the catalyst 154 (e.g., proximate an inlet of the catalyst 154).In embodiments where the aftertreatment component 150 includes the SCR system, the performance of the SCR system 150 may decrease to a level at which the SCR system 150 has a first catalytic conversion efficiency at which the NOx outlet amount (e.g., determined by the NOx outlet sensor 105) exceeds a predetermined threshold (e.g., a maximum allowable NOx outlet amount according to an emissions standard). The catalyst active material container 140 may be activated to selectively route the catalyst active material to the SCR system 150 in situ (i.e., without removing the SCR system 150 or the catalyst 154 from the aftertreatment system 100) to restore the catalyst 154.In other embodiments, the SCR system 150 may be removed from the aftertreatment system 100 upon determining that the SCR system 150 is deactivated (e.g., the catalyst 154 of the SCR system 150 is deactivated). The active catalyst material container 140 is then fluidly coupled to the SCR system housing 152 (e.g., via the reductant injection port 156 or the temperature sensor port 158) to route a predetermined amount of the active catalyst material (e.g., in the range of 0-100% by weight including all ranges and values therebetween), thereby coating at least a portion of the catalyst 154 of the SCR system 150 and recovering the SCR system 150.As a result of the further expansion, the active catalyst material solution or suspension supplied to the aftertreatment component 150 (e.g., the SCR system 150) for the predetermined time causes the active catalyst material to form a coating on at least a portion of the aftertreatment component 150 (e.g., on a surface of the catalyst 154). The coating of the fresh active catalyst material increases the catalytic conversion efficiency of the aftertreatment component 150 such that the aftertreatment component 150 has a second catalytic efficiency that is higher than the first catalytic conversion efficiency. For example, the second catalytic conversion efficiency allows the SCR system 150 to decompose a sufficient amount of the NOx gases contained in the exhaust gas by the SCR system 150 so that the NOx outlet amount falls below the predetermined limit value (i.e., is within an allowable range that is below the maximum allowable NOx amount that can be discharged from the aftertreatment system 100).In various embodiments, the forwarding of the active catalyst material to the aftertreatment component 150 for the predetermined time causes the active catalyst material to form a coating having a predetermined average thickness on a surface of the catalyst 154. In some embodiments, the predetermined time is selected to allow an amount of the active catalyst material in the range of 0-100% by weight, including all ranges and values therebetween. In particular embodiments, the amount of active material to be coated or deposited is in the range of 5 wt% to 30 wt% (e.g., 5, 6, 7, 8, 9, 10, 15, 20, 25 or 30 wt%, including all ranges and values therebetween).The active catalyst material container 140 is contained within the aftertreatment system 100 and fluidly coupled to the aftertreatment component 150 to route the active catalyst material before or to at least a portion of the catalyst 154 without removing the aftertreatment component 150 (e.g., the SCR system 150) from the aftertreatment system 10. An active catalyst material delivery assembly (not shown) may be fluidly coupled to the active catalyst material container 140 and configured to deliver the active catalyst material (e.g., a solution or suspension of the active catalyst material) to the aftertreatment component 150. The active catalyst material delivery assembly may include any suitable structure, e.g., pumps, valves, liquid conduits, filters, etc., for delivering the active catalyst material to the aftertreatment component 150.In an embodiment where the aftertreatment component 150 includes the SCR system 150, the active catalyst material container 140 may be fluidly coupled to the SCR system 150 via the reductant injection port 156 disposed on the housing 152 (e.g., before or over the catalyst 154). In such embodiments, delivery of the reductant to the SCR system 150 may be stopped before the active catalyst material is delivered to the SCR system 150. In other embodiments, the active catalyst material may be gradually transferred after the reducing agent is transferred into the SCR system 150. For example, both the reductant and the active catalyst material may be relayed to the SCR system 150 in pulses such that a relaying pulse for active catalyst material is generated between two reductant relaying pulses.For example, the engine fluidly coupled to the aftertreatment system 100 may be operated under low load conditions (e.g., idle or continuous operation) for the predetermined time to reduce, e.g., an exhaust flow rate and / or the amount of NOx gases generated by the engine. The solution or suspension of the catalyst active material comes into contact with the exhaust gas and is supplied to the catalyst 154 as it passes through the SCR system 150 to form a layer thereon. In some embodiments, the carrier media or fluid in which the active catalyst material is dissolved or suspended may evaporate upon contact with the exhaust gas. As such, particles of the active catalyst material may be released, which are entrained in the exhaust gas and flow onto the SCR system 150 to coat the catalyst 154.In other embodiments, the active catalyst material may be passed to the SCR system 150 simultaneously with the reductant. The engine may be operated under low or high load conditions (e.g., accelerating) when passing the active catalyst material into the SCR system 150 with the reductant. In still other embodiments, the active catalyst material may be passed to the SCR system 150 after the aftertreatment system 100 is shut down. In such embodiments, the catalyst active material delivery assembly may be configured to deliver the catalyst active material to the SCR system 150 under sufficient pressure to allow coating of the catalyst 154 with the catalyst active material.In some implementations, the catalyst active material container 140 may be fluidly coupled to the SCR system 150 via the temperature sensor port 158. For example, temperature sensor port 158 may include an opening for receiving an active catalyst material supply line from active catalyst material container 140 and for passing the active catalyst material (e.g., a solution or suspension thereof) into SCR system 150. The active catalyst material may be routed to the SCR system 150 via the temperature sensor port 158 independently of the reductant routed to the SCR system 150 (e.g., simultaneously with the reductant, incrementally with the reductant, or upon completion of reductant delivery to the SCR system 150).Aftertreatment system 100 may include other components besides aftertreatment component 150, such as one or more flow mixers, temperature sensors, pressure sensors, oxygen sensors, ammonia sensors, and / or any other components.The controller 170 is communicatively coupled to the outlet sensor 105, optionally also to the active catalyst material container 140, the NOx inlet sensor 103, and the reductant delivery member 120. The controller 170 may include any suitable controller, for example, the computing device 630 described in detail herein. The controller 170 is configured to interpret an output signal of the exhaust sensor 105. The output signal serves as an indicator of the performance of the aftertreatment component 150, for example, catalytic conversion efficiency of the aftertreatment component or wear of the aftertreatment component 150. For example, the aftertreatment component 150 may include an SCR system 150 and the outlet sensor 105 may include a NOx outlet sensor 105. The output signal may correspond to a single NOx exhaust signal indicative of the NOx exhaust amount of the NOx gases contained in the exhaust gas after passing through the SCR system 150.The controller 170 may determine whether the aftertreatment component 150 is deactivated or otherwise worn. For example, the controller 170 may determine the NOx outlet amount from the output NOx signal. For example, the controller 170 may include algorithms, tables, or equations configured to evaluate the reductant quality to determine the NOx exhaust amount. The controller 170 may determine an absolute value of the NOx exhaust amount. In some embodiments, the controller 170 is configured to determine an expected range of the NOx exhaust amount from the NOx exhaust signal.In particular embodiments, aftertreatment system 100 may include a plurality of aftertreatment components as described herein. The aftertreatment system 100 may include a plurality of sensors positioned and configured to determine the performance of a corresponding aftertreatment component. Each of the plurality of aftertreatment components may be communicatively coupled to the controller 170. Each of the plurality of sensors may generate an output signal indicative of the performance of the corresponding aftertreatment component. The controller 170 determines which of the aftertreatment components is deactivated and is to be recovered.In some embodiments, the controller 170 is configured to interpret a NOx input signal from the NOx inlet sensor 103 and determine the NOx input amount therefrom. The controller 170 may also use the NOx input amount to determine the NOx outlet amount (e.g., normalize or correct the NOx outlet amount determined by the NOx outlet sensor 105 using the NOx input amount).In response to determining that aftertreatment component 150 has been deactivated, controller 170 provides an active catalyst material to at least a portion of aftertreatment component 150. The active catalyst material coats at least the portion of the aftertreatment component 150 to restore the aftertreatment component 150 as described herein. For example, the controller 170 may activate the active catalyst material container 140 included in the aftertreatment system 100 to route the active catalyst material to the aftertreatment component 150 without removing the aftertreatment component 150 from the aftertreatment system 100.In other embodiments, the controller 170 may indicate to a user that the aftertreatment component 150 is deactivated and needs to be recovered, for example, by illuminating a fault indicator (MIL) or generating an error code. The user, service technician, or other personnel may then remove the aftertreatment component 150 from the aftertreatment system 100 and recover the aftertreatment component 150 without removing the catalyst 154 from the housing 152 of the aftertreatment component 150, as described herein.The aftertreatment component 150 may include the SCR system 150. The controller 170 determines whether the NOx outlet amount exceeds the predetermined threshold. The controller 170 activates the active catalyst material container 140 for a predetermined time to route a predetermined amount of the active catalyst material to the SCR system 150 when the NOx outlet amount exceeds the predetermined threshold (e.g., a maximum allowable amount of NOx that may be discharged from the aftertreatment system 100 during operation).In some embodiments, the controller 170 may activate the active catalyst material container 140 regardless of the operating state of the engine fluidly coupled to the aftertreatment system 100. For example, once the controller 170 determines that the NOx outlet amount exceeds the predetermined threshold, the controller 170 activates the active catalyst material container 140 regardless of whether the engine is running under low or high load.In some embodiments, the controller 170 may be configured to wait a predetermined standby time after the aftertreatment system 100 is started before deciding whether or not to activate the active catalyst material canister. This predetermined standby time may be selected such that aftertreatment system 100 may heat up to an operating temperature of the aftertreatment system. For example, if the SCR system 150 is cold, it may have a degraded catalytic conversion efficiency until it warms up to its operating temperature. As a result, the NOx outlet amount may exceed the predetermined threshold until the SCR system 150 warms up even if the catalyst 154 of the SCR system 150 is not worn to an unacceptable level. The predetermined standby time allows the SCR system 150 to be heated to the operating temperature before the controller 170 determines the NOx outlet amount. Once the SCR system 150 is warmed to its operating temperature, the NOx outlet amount overshoot is due to the degradation of the catalyst 154, rather than the SCR system 150 being operated cold, thereby avoiding false alarms.In some implementations, the controller 170 may be configured to deactivate the reductant delivery member 120 prior to activation of the catalyst active material container 140. In particular embodiments, the controller 170 may synchronize delivery of the active catalyst material (e.g., a solution or suspension thereof) to the SCR system 150 with delivery of the reductant thereto. For example, the controller 170 may alternately route the reductant and the active catalyst material to the SCR system 150 (e.g., via a series of sequential reductant forwarding pulses and active catalyst material forwarding pulses, as described above).In still other embodiments, the controller 170 may be configured to indicate to a user that the SCR system 150 is degraded. For example, the controller 170 may generate an error code or illuminate a fault indication (MIL) (e.g., on a dashboard of a vehicle, industrial equipment, locomotive, ship, or other system including the engine and aftertreatment system 100) that indicates to the user that the SCR system has worn beyond a reasonable amount. In some embodiments, the user may manually activate the active catalyst material container 140 at any time for the predetermined time to deliver the predetermined amount of active catalyst material to the SCR system 150. For example, the user may activate the active catalyst material container 140 when the engine is off or operating under low load conditions. In this manner, the SCR system 150 is recovered and recovers at least a portion of its catalytic conversion efficiency lost through degradation.In certain embodiments, the controller 170 may be included in a control circuit. For example, FIG. 2 is a schematic block diagram of a control circuit 171 including the controller 170, according to an embodiment. The controller 170 may include a processor 172, a storage element 174, or other computer readable medium, a transceiver 178, and optionally a sensor 176. It should be appreciated that the controller 170 only shows one embodiment of the controller 170, and any other controller capable of performing the tasks described herein may also be used.The processor 172 may include a microprocessor, a programmable logic controller (PLC) chip, an ASIC chip, or another suitable processor. The processor 172 communicates with the memory 174 and is configured to execute instructions, algorithms, instructions, or other programs stored in the memory 174. Memory 174 includes all memory space components discussed herein. For example, the memory 174 may include the memory and / or cache of the processor 172. The memory 174 may also include one or more storage devices (e.g., hard drives, flash drives, computer readable media, etc.), either local or remote to the controller 170. The memory 174 is configured to store look-up tables, algorithms, or instructions.For example, the memory 174 includes a performance determination circuit 174 athat interprets the output signal of the exhaust sensor 105 to determine the performance (e.g., catalytic conversion efficiency or whether the aftertreatment component 150 is deactivated) of the aftertreatment component 150. For example, the power determination circuit 174 amay interpret the NOx exhaust signal of the NOx exhaust sensor 105 (e.g., via the sensor 176). As described above, the NOx exhaust signal is an indicator of the NOx exhaust amount. The NOx outlet amount determination circuit 174 amay be configured to determine the NOx outlet amount from the NOx outlet signal. The NOx outlet amount determination circuit 174 adetermines whether the NOx outlet amount exceeds the predetermined threshold (e.g., a maximum allowable NOx amount as described herein).The storage 174 also includes active catalyst material relay circuitry 174 bfor selectively activating the active catalyst material container 140 (e.g., included in or separated from the aftertreatment system 100). For example, if the power determination circuit 174 adetermines that the aftertreatment component 150 is deactivated (e.g., the NOx outlet amount exceeds the predetermined threshold), the power determination circuit 174 a instructs the active catalyst material relay circuit 174 bto activate the active catalyst material canister 140.The controller 170 also includes a transceiver 178 for generating a catalyst relay signal (e.g., current or voltage) to activate the catalyst active material container 140. In some embodiments, transceiver 178 may also be configured to indicate to a user that aftertreatment component 150 (e.g., SCR system 150) is worn. For example, the alert signal may generate an error code or illuminate a malfunction indicator (MIL) light located, for example, in a dashboard of a vehicle or aftertreatment system 100.FIG. 3 is a schematic illustration of an aftertreatment system 200 according to another embodiment. The aftertreatment system 200 may be fluidly coupled to an engine and configured to decompose constituents (e.g., NOx gases) contained in an exhaust gas generated by the engine. The engine may include an internal combustion engine that may be operated with diesel, gasoline, natural gas, biodiesel, ethanol, liquefied petroleum gas (LPG), or any other fuel source. The aftertreatment system 200 includes an SCR system 250, a reductant storage tank 210, a reductant delivery member 220, a catalyst active material container 240, and a controller 270. In other embodiments, aftertreatment system 200 may include any other aftertreatment component, such as an oxidation catalyst, a catalyzed filter, and / or an ammonia oxidation catalyst, in addition to or in place of SCR system 250.The aftertreatment system 200 is comprised of an inlet pipe 202 for receiving the exhaust gas (e.g., a diesel exhaust gas) of an engine (e.g., a diesel engine), and an outlet pipe 204 configured to drain the treated exhaust gas to the environment. A NOx inlet sensor 203 is located upstream of the SCR system 250 near an inlet of the inlet pipe 202 and is configured to determine an NOx inlet amount of NOx gases including the exhaust gas entering the aftertreatment system 200. The SCR system 250 is positioned between the inlet pipe 202 and the outlet pipe 204.A NOx outlet sensor 205 is located behind the SCR system 250, for example, in the outlet pipe 204, and is configured to determine a NOx outlet amount of the NOx gases contained in the exhaust gas after passing through the SCR system 250. The NOx inlet sensor 203 and the NOx outlet sensor 205 may be substantially similar to the NOx inlet sensor 103 and the NOx outlet sensor 105, and therefore will not be described in further detail herein.The SCR system 250 includes a housing 252 that defines an interior volume in which a catalyst 254 is located. The SCR system 250 and the catalyst 254 may be substantially similar to the SCR system 150 and the catalyst 154, and therefore will not be described in further detail herein. A reductant injection port 256 is located on a sidewall of the housing 252 and is configured to allow a reductant to be introduced into the interior volume defined by the housing 252. The reductant injection port 256 may be upstream of the catalyst 254 (e.g., to allow the reductant to be injected into the exhaust gas upstream of the catalyst 254) or disposed above the catalyst 254 (e.g., to allow the reductant to be directly injected into the catalyst 254).The reducing agent storage tank 210 is configured to store a reducing agent (e.g., a diesel exhaust liquid such as an aqueous urea solution). A reducing agent supply member 220 is fluidly connected to the reducing agent storage tank 210. The reductant delivery component 220 is configured to receive the reductant from the reductant storage tank 210 and selectively insert the reductant into or upstream of the SCR system 250 (e.g., the inlet pipe 202) or a mixer (not shown) upstream of the SCR system 250. The reducing agent storage tank 210 and the reducing agent supply member 220 may be substantially similar to the reducing agent storage tank 110 and the reducing agent supply member 120, and thus will not be described in detail herein.The catalyst active material container 240 is configured to contain a catalyst active material therein. As shown in FIG. 3, the active catalyst material container 240 includes a chamber 242 on a side wall of the housing 252 in which a container 244 containing the active catalyst material is disposed. The chamber 242 is located near the catalyst, for example, aligned with the catalyst within the housing 252, in front of the catalyst 254 within the housing 252, or at a distance less than half the cross-sectional width of the catalyst 254 of the SCR system 250.The active catalyst material may include the same active catalyst material as the aftertreatment system 100. The chamber 242 is selectively fluidly couplable to an interior volume defined by the housing 252 such that the active catalyst material contained within the container 244 may be forwarded to the catalyst as needed. For example, chamber 242 may include a door or valve configured to be selectively opened to fluidly couple chamber 242 to the interior volume defined by housing 252 to enable the active catalyst material to be conveyed thereto.The container 244 may comprise a decomposable container configured to dissolve upon exposure to suitable triggers. For example, the container 244 may be decomposed by heating to a predetermined temperature to release the active catalyst material contained therein. The active catalyst material may be stored in the container 244 of the active catalyst material container 240 in the form of a solution, suspension, powder or crystals of the active catalyst material, or other suitable form. In some embodiments, the container 244 may be degraded by exposure to a chemical compound (e.g., an acid, a base, or the reducing agent). In other embodiments, the container 244 may include a frangible container configured to rupture or crack to release the active catalyst materials contained therein.In some embodiments, the container 244 may be decomposable by heat. In such embodiments, a heat source 246 may be operatively coupled to the chamber 242. The heat source 246 is configured to selectively heat the chamber 242, and thus the container 244, to dissolve the container 244. In some embodiments, the heat source 246 may include an electric heater. In other embodiments, the heat source 246 may include heat generated by the engine.For example, the heat source 246 may include one or more tubes configured to selectively discharge a heated engine coolant that conducts heat away from the engine or a portion of the exhaust gas generated by the engine into the space 242. The heated coolant or portion of the exhaust gas heats the chamber 242 and thereby decomposes the degradable container 244 therein to release the catalyst material contained therein. The chamber 242 may be thermally insulated from the housing 252 so that the hot exhaust flowing through the housing 252 of the SCR system 250 does not heat the chamber 242.As described above, the active catalyst material container 240 may be activated once the performance of the SCR system 250 drops to a level at which the SCR system 250 has a first catalytic conversion efficiency at which the NOx outlet amount (e.g., determined by the NOx outlet sensor 205) exceeds a predetermined threshold (e.g., a maximum allowable NOx outlet amount according to an emissions standard). The catalyst active material container 240 may be activated to selectively pass the catalyst active material to the SCR system 250 in situ (i.e., without removing the SCR system 250 or the catalyst 254 from the aftertreatment system 200) to restore the catalyst 154.The controller 270 is communicatively coupled to the catalyst active material container 240, the NOx outlet sensor 205, and optionally also to the heat source 246, the NOx inlet sensor 203, and the reductant delivery member 220. Controller 270 may be very similar in structure and function to controller 170. The controller 270 is configured to interpret a NOx exhaust signal from the NOx exhaust sensor 205. The NOx exhaust signal is an indicator of an NOx exhaust amount of the NOx gases contained in the exhaust gas after passing through the SCR system 250. For example, the controller 270 may include the NOx outlet amount determination circuit 174 aconfigured to evaluate the NOx outlet signal.The controller 270 may also determine the NOx exhaust amount (e.g., an absolute value or range from the NOx exhaust signal). In some embodiments, the controller 270 is configured to evaluate an input NOx signal from the NOx inlet sensor 203 and determine the input NOx quantity therefrom. The controller 270 may also use the NOx input amount to determine the NOx outlet amount (e.g., normalize or correct the NOx outlet amount determined by the NOx outlet sensor 205 using the NOx input amount).The controller 270 determines whether the NOx outlet amount exceeds a predetermined threshold (e.g., using the NOx determination circuit 174 aincluded in the controller 270). Upon exceeding the NOx outlet amount, the controller 270 activates the active catalyst material container 240 for a predetermined time to deliver a predetermined amount of the active catalyst material to the SCR system 250.For example, the controller 270 may also include the active catalyst material relay circuit 174 b. When the NOx outlet amount exceeds the predetermined threshold, the controller 270 or the active catalyst material relaying circuit 174 bincluded in the controller 270 may activate the heat source 246 for a certain time. This causes the heat source 246 to heat the chamber 242, and thus the heat degradable container 244, with the active catalyst material.As a result of the temperature increase, the container 244 decomposes and discharges the active catalyst material contained therein into the chamber 242. The controller 270 or active catalyst material delivery circuit 174 bmay also be configured to fluidly couple the chamber 242 to the interior volume of the housing 252 (e.g., by opening a door or operating a valve) and so deliver the active catalyst material to the catalyst 254 of the SCR system 250.It should be appreciated that while the aftertreatment system 200 includes the SCR system 250 and the active catalyst material container 240 thereon or in proximity thereto, in other embodiments, the aftertreatment system 200 may include any other aftertreatment component including a catalyst as described herein. Individual active catalyst material containers 240 may be disposed on or near the aftertreatment components and contain an active catalyst material specifically formulated for the respective aftertreatment component. When one of the aftertreatment components is deactivated, only the corresponding active catalyst material reservoir 240 on or near the respective aftertreatment component is activated (e.g., via the controller 270 operatively connecting the heat source 246) to only route the active catalyst material to the respective aftertreatment component and restore the respective aftertreatment component.FIG. 4 is a schematic flow diagram of an example method 300 for recovering an SCR system (e.g., SCR system 150 / 250) in an aftertreatment system (e.g., aftertreatment system 100 / 200). In method 300, an exhaust gas is directed through the aftertreatment system at 302. For example, the aftertreatment system may be fluidly coupled to an engine (e.g., a diesel engine) that generates the exhaust gas (e.g., a diesel exhaust gas).An NOx outlet amount of the NOx gases contained in the exhaust gas after flowing through the aftertreatment system is determined at 304. For example, the controller 170 / 270 interprets a NOx exhaust signal from the NOx exhaust sensor 105 / 205 and determines the NOx exhaust amount therefrom. Method 300 determines whether the NOx exhaust amount exceeds a predetermined threshold at 306. For example, whether the NOx outlet amount exceeds the predetermined threshold is determined by the controller 170 / 270 or the NOx outlet amount determination circuit 174a included in the controller 170 / 270.If the NOx exhaust amount does not exceed the predetermined threshold, the method returns to operation 304. On the other hand, if the NOx outlet amount exceeds the predetermined threshold, the active catalyst material is forwarded to the SCR system for a predetermined time at 308. For example, the controller 170 activates the catalyst active material container 140 for the predetermined time to deliver a predetermined amount of the catalyst active material to the SCR system 150. Similarly, the controller 270 may activate the heat source 246 for a certain time to heat and dissolve the container 244. This delivers the predetermined amount of active catalyst material contained in the container 244 to the SCR system 250.FIG. 5 is a schematic flow diagram of another example method 400 for recovering a deactivated aftertreatment component (e.g., aftertreatment component 150 / 250). Method 400 includes providing an aftertreatment component of an aftertreatment system that includes a spent catalyst at 402. For example, aftertreatment component 150 / 250 is provided that includes spent catalyst 154 / 254.An indication is provided that the catalyst is deactivated at 404. For example, the controller 170 / 270 indicates to a user that the catalyst 154 / 254 included in the aftertreatment component 150 / 250 is deactivated. In response to the indication that the catalyst is deactivated, the catalyst is coated with a coating of an active catalyst material to restore the catalyst at 408. For example, the active catalyst material 140 / 240 is fluidly coupled to the aftertreatment component 150 / 250 to supply the active catalyst material to the deactivated catalyst 154 / 254 and coat the catalyst 154 / 254.In some embodiments, the catalyst is coated with the active catalyst material while the aftertreatment component is coupled to the aftertreatment system. For example, aftertreatment system 100 / 200 also includes active catalyst material container 140 / 240 fluidly coupled to aftertreatment component 150 / 250. The controller 170 / 270 determines whether the catalyst 154 / 254 is deactivated and then activates the catalyst active material container 140 / 240 to pass the catalyst active material to the aftertreatment component 150 / 250 without decoupling the aftertreatment component 150 / 250 from the aftertreatment system 100 / 200.In other embodiments, the method 400 also includes decoupling the aftertreatment component from the aftertreatment system at operation 406 prior to coating the catalyst with the active catalyst material at operation 408. For example, if it is determined that aftertreatment component 150 / 250 or catalyst 154 / 254 contained therein is deactivated (e.g., by controller 170 / 270), aftertreatment component 150 / 250 is decoupled from aftertreatment system 100. The active catalyst material container 140 / 240 may then be fluidly coupled to the housing 152 / 252 of the aftertreatment component 150 / 250 as described herein to supply the active catalyst material to the catalyst 154 / 254 disposed in the housing 152 / 252 without removing the catalyst 154 / 254 from the housing 152 / 252.FIG. 6 panel A is a side view of a catalyst of an SCR system that has been in operation for some time, and FIG. 6 panel B is an enlarged view thereof. The catalyst contains a 2.5 cm x 7.6 cm (1 inch x 3 inch) core. The catalyst was coated with 10% or 20% by weight of active catalyst material and calcined in a standard air oven. The catalyst was not pretreated before the coating, so that the hydrocarbons or poisons present in the catalyst remain therein before the coating process.FIG. 6 panel C is a side view of the SCR catalyst of FIG. 6 panel A / B after coating with 10% active catalyst material, and FIG. 6 panel D is an enlarged view thereof. FIG. 6 panel E is a side view of the SCR catalyst of FIG. 6 panel A / B after coating with 20% active catalyst material, and FIG. 6 panel F is an enlarged view thereof. The distance between the cells of the catalyst after coating was visually observed. The adhesion of the catalyst material deposited on the catalyst was determined by means of an air gun. After coating, no cell plugging or other significant structural differences were observed.For determination of the catalytic conversion efficiency of the individual catalysts, a new catalyst, a spent catalyst, the spent catalyst at 10 wt % (hereinafter referred to as "the spent 10 catalyst"), and the spent catalyst at 20 wt % (hereinafter referred to as "the spent 20 catalyst") were each coated with active material. For testing, the catalysts were exposed to an air stream of 500 ppm NO, 500 ppm NH 3, 10 % O 2, 5 % CO 2 and 5% water to simulate an exhaust gas.FIG. 7 is a bar graph of catalytic NOx conversion efficiency at 220 and 550 degrees Celsius of the spent catalyst, the spent 10 catalyst, the spent 20 catalyst, and the new catalyst and its ammonia oxidation efficiency. The spent 10 catalyst and the spent 20 catalyst show a marked improvement in catalytic conversion efficiency toward NOx conversion at 250 degrees Celsius and 520 degrees Celsius over the spent catalyst. The spent 10 catalyst and the spent 20 catalyst also have significantly higher ammonia conversion efficiency at 520 degrees Celsius than the spent and new catalysts.FIG. 8 is a bar graph of ammonia storage capacity of spent catalyst, spent 10 catalyst, spent 20 catalyst material, and new catalyst. Both the spent 10 catalyst and the spent 20 catalyst have a significantly higher ammonia storage capacity than the spent catalyst.In some embodiments, controller 170 / 270, control circuitry 171, or one / r of the controllers or control circuitry described herein may comprise a system computer of an apparatus or system that includes aftertreatment system 100 (e.g., a vehicle, motor, or generator set, etc.). For example, FIG. 9 is a block diagram of a computing device 630 according to an illustrative implementation. Computing device 630 may be used to perform any of the methods or processes described herein, e.g., method 300. In some implementations, the controller 170 may include the computing device 630. Computing device 630 includes a bus 632 or other communication component for communication of information. Computing device 630 may also include one or more processors 634 or processing circuitry coupled to information processing bus 632.Computing device 630 also includes main memory 636, such as random access memory (RAM) or other dynamic memory, coupled to bus 632 for storing information and instructions executed by processor 634. Main memory 636 may also be used to store position information, temporary variables, or other intermediate information during execution of instructions by processor 634. Computing device 630 may further include a ROM 638 or other static storage medium coupled to bus 632 for storing static information and instructions for processor 634. A storage device 640, such as a solid state device, magnetic disk, or optical disk, is coupled to bus 632 to permanently store information and instructions. For example, instructions may be stored in the memory device 640 to determine the initial flow velocity and compare the initial flow velocity to the predetermined threshold and increase or decrease the corresponding cross-sectional area of the exhaust conduit.Computing device 630 may be coupled via bus 632 to a display 644, such as a liquid crystal display or an active matrix display, for displaying information to a user. An input device 642, such as a keyboard or alphanumeric keyboard, may be coupled to bus 632 for communicating information and command selection for processor 634. In another embodiment, the input device 642 includes a display 644, e.g., a touch screen display.According to various implementations, the processes and methods described herein may be implemented by computing device 630 in response to processor 634 executing a series of instructions contained in main memory 636 (e.g., the operations of method 300). These instructions may be read into main memory 636 from another non-transitory computer readable medium, such as storage device 640. Execution of the various instructions contained in main memory 636 causes computing device 630 to perform the operations described herein. One or more processors in a multiprocessor array may also be employed to execute the instructions contained in main memory 636. In alternative implementations, wired circuitry may be used in place of or in combination with software instructions to implement the described implementations. Thus, the implementations are not limited to any particular combination of hardware and software.Although an example computing device has been described in FIG. 9, the implementations described in this specification can be implemented in other types of digital electronics or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them.Implementations described in this specification can be implemented in digital electronics or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. The implementations described in this specification may be implemented as one or more computer programs (i.e., as one or more circuits of computer program instructions encoded on one or more computer storage media for execution by or to the controller of the operation of data processing devices). Alternatively or additionally, the program instructions may be encoded in an artificially generated propagated signal, e.g., a machine generated electrical, optical, or electromagnetic signal, generated to encode information for transmission to a suitable receiver device for execution by a computing device. A computer storage medium may be, or be included in, a computer readable storage unit, a computer readable storage substrate, a serial(s) or dynamic(r) random access memory or device, or a combination of one or more thereof. Further, although a computer storage medium is not a transmitted signal, a computer storage medium may be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium may also be or may be included in one or more separate components or media (e.g., multiple CDs, disks, or other storage devices). Thus, the computer storage medium is both tangible and non-transitory.The operations described in this specification may be performed by a computing device on data stored on one or more computer readable storage devices or received from other sources. The term "computing device" or "computing device" includes any type of device, device, and machine for processing data, including, for example, by a programmable processor, a computer, a system on a chip, or multiple, or combinations of the foregoing. The apparatus may include special purpose logic (e.g., an FPGA (Universal Circuit) or an ASIC (Application Specific Integrated Circuit)). The apparatus may also include, in addition to hardware, code that creates an execution environment for the subject computer program, e.g., code representing processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of these. The apparatus and execution environment may implement various computer model infrastructures, such as web services, distributed computer and spatially distributed computer infrastructures.A computer program (also known as a program, software, software application, script, or code) may be written in any form of programming language (including compiled or interpreted languages and declarative or procedural languages), and may be deployed in any form (including as a stand-alone program or as a schematic, component, subroutine, object, or other unit suitable for use in a computing environment). A computer program may, but need not, correspond to a file in a file system. A program may be stored in a portion of a file containing other programs or data (e.g., one or more scripts stored in a markup language document), in a single dedicated file for the program in question, or in multiple coordinated files (e.g., files in which one or more switching schemes, subroutines, or portions of code are stored). A computer program may be deployed to run on one computer or on multiple computers located at one location or across multiple locations and interconnected by a communications network.Processors suitable for executing a computer program include, for example, both general and special purpose microprocessors, and any one or more processors of any type of digital computer. Generally, a processor receives instructions and data from a read-only memory or a random-access memory, or both. The essential elements of a computer are a processor for performing operations according to instructions and one or more storage devices for storing instructions and data. Generally, a computer also includes or is operatively coupled to one or more mass storage devices for storing data, or for receiving or transmitting data, or both, such as magnetic, magneto-optical disks, or optical disks. However, a computer does not need to have these devices. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices, e.g., EPROM, EEPROM, and flash storage devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by or incorporated into special purpose logic.It should be appreciated that the term "example" as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and / or illustrations of possible embodiments (and that such term is not necessarily intended to suggest that such embodiments are exceptional or excellent examples).As used herein, the term "coupled" and the like means the direct or indirect connection of two elements to each other. This connection may be stationary (e.g., permanent) or movable (e.g., removable or releasable). This connection can be achieved by making the two elements or the two elements and any other intermediate elements integral with each other as a unitary body, or by fixing the two elements or the two elements and any other intermediate elements to each other.It is to be understood that the structure and arrangement of the various exemplary embodiments are illustrative only. Although only some embodiments have been described in detail in this disclosure, those skilled in the art will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and portions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) upon reading this disclosure without materially departing from the novel teachings and advantages of the subject matter described herein. Additionally, it should be understood that features from one embodiment disclosed herein may be combined with features from other embodiments disclosed herein, as is known to one of ordinary skill in the art. Other substitutions, modifications, changes, and omissions may also be made in the construction, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of the present invention.While this specification contains many specific embodiments, these should not be taken as limiting the scope of all inventions or the claims, but rather as describing features specific to particular embodiments of particular inventions. Certain features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. In contrast, various features described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although above features may be described as acting in certain combinations and also initially claimed as such, one or more features from a claimed combination may in some cases be excluded from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

Claims

An exhaust aftertreatment system (100) comprising: an aftertreatment component (150; 250); an outlet sensor (105) downstream of the aftertreatment component; and an active catalyst material container (140; 240) fluidly coupled to the aftertreatment component (150) and a controller (170) communicatively coupled to the outlet sensor (105) and the active catalyst material container (140), the controller (170) configured to: evaluate an output signal of the outlet sensor (105) indicative of a performance of the aftertreatment component (150), determine whether the aftertreatment component (150) is deactivated, and in response to determining that the aftertreatment component (150) is deactivated, activate the active catalyst material container (140) to provide a predetermined amount of an active catalyst material to at least a portion of the aftertreatment component (150), wherein the active catalyst material coats at least the portion of the aftertreatment component to restore the aftertreatment component (150).The exhaust aftertreatment system of claim 1, wherein the aftertreatment component (150) has a first catalytic conversion efficiency prior to coating the active catalyst material thereon, and wherein coating the active catalyst material on the aftertreatment component (150) causes a second catalytic conversion efficiency higher than the first catalytic conversion efficiency.The exhaust aftertreatment system of claim 1 or 2, wherein the aftertreatment component (150) comprises a catalyst (154; 254) through which the exhaust gas flows, and wherein the coating of the active catalyst material is formed on the catalyst (154).The exhaust aftertreatment system of any of claims 1 to 3, wherein the aftertreatment component (150) is coated with the active catalyst material while the aftertreatment component (150) is coupled to the exhaust aftertreatment system (100).The exhaust aftertreatment system of claim 1, wherein the aftertreatment component (150) comprises a housing (152) defining an interior volume in which the catalyst (154) is located.The exhaust aftertreatment system of claim 5, wherein the aftertreatment component (150) comprises a selective catalytic reduction system, and wherein the active catalyst material container (140) is fluidly coupled to the selective catalytic reduction system via at least one reductant injection port (156) and a temperature sensor port (158) disposed on the housing.The exhaust aftertreatment system of claim 1, wherein the active catalyst material container (240) comprises a degradable container (244) containing the active catalyst material.The exhaust aftertreatment system of claim 7, further comprising: a heat source (246) operatively coupled to the degradable canister (240), wherein the controller (270) is further configured to activate the heat source (246) to heat the degradable canister (244), wherein the degradable canister is configured to decompose by the heat to deliver the active catalyst material to the aftertreatment component (250).The exhaust aftertreatment system of claim 1, wherein the active catalyst material includes a solution of the active catalyst material, a suspension of the active catalyst material, or a powder of the active catalyst material.The exhaust aftertreatment system of any of claims 1 to 9, wherein the active catalyst material is provided in the range of greater than 0 wt% and less than 100 wt%.A method comprising: providing an aftertreatment component (150; 250) disposed in an exhaust aftertreatment system (100; 200), the aftertreatment component (150) including a catalyst (154; 254) used in the exhaust aftertreatment system; determining that the catalyst (154) is deactivated, and responsive to determining that the catalyst (154) is deactivated, causing a catalyst active material container (140) fluidly coupled to the aftertreatment component (150) to provide a predetermined amount of a catalyst active material to the aftertreatment component (150) to coat the catalyst with the catalyst active material without removing the aftertreatment component (150) from the exhaust aftertreatment system (100) to restore the catalyst.The method of claim 11, wherein the coating of the catalyst (154) with the active catalyst material is performed while the aftertreatment component (150) is coupled to the exhaust aftertreatment system (100).The method of claim 11, further comprising introducing a first pulse of a reductant into the aftertreatment component (150) prior to the catalyst (154).The method of claim 13, further comprising introducing the active catalyst material into the catalyst (154) after introducing the first pulse of the reductant into the aftertreatment component (150).The method of claim 14, further comprising introducing a second pulse of the reductant into the aftertreatment component (150) after the introduction of the active catalyst material.The method of claim 13, further comprising introducing the active catalyst material into the catalyst (154) simultaneously with introducing the first pulse of the reductant into the aftertreatment component (150).The method of any one of claims 11 to 16, wherein the active catalyst material comprises the same material as the catalyst (154).The method of any of claims 11 to 17, wherein coating the catalyst (154) with the active catalyst material increases a catalytic conversion efficiency of the aftertreatment component (150).A method comprising: providing an aftertreatment component (150; 250) disposed in an exhaust aftertreatment system (100; 200), the aftertreatment component (150) comprising a catalyst (154; 254) used in the exhaust aftertreatment system (100); determining whether the catalyst (154) is deactivated; in response to determining that the catalyst (154) is deactivated, coating the catalyst (154) with a coating of an active catalyst material to restore the catalyst (154) by: introducing a first pulse of a reductant to the aftertreatment component (150) upstream of the catalyst (154), and introducing the active catalyst material to the catalyst (154) simultaneously with introducing the first pulse of the reductant to the aftertreatment component (150).

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