Systems and methods for reducing the formation of reducing agent deposits in a decomposition reactor of an exhaust aftertreatment system for an internal combustion engine

Abstract

Exhaust aftertreatment system (100, 200, 1800, 2000), comprising: a decomposition reactor (202, 1802, 2002), comprising: a body (203, 1803, 2003) through which exhaust gas can flow, the body comprising: an inlet (204, 1804, 2004) configured to receive the exhaust gas at a first temperature, and an outlet (206, 1806, 2006) configured to expel the exhaust gas at a second temperature higher than the first temperature, an impact structure (214, 402, 602, 708, 808, 1006, 1204, 1600) arranged within the body between the inlet and the outlet, the impact structure extending into the body and arranged such that that the exhaust gas flowing through the body impacts the impact structure, a heating device (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) coupled to the impact structure and configured to selectively heat the impact structure, and a guide (704, 804, 1816,2012), which is coupled downstream of the inlet (204, 1804, 2004) to the body (203, 1803, 2003), the guide comprising a plurality of guide apertures (705, 805, 1817) configured to receive the exhaust gas from the inlet; an injection device (210, 500, 1810, 2010) configured to inject reducing agent into the body; and a processor programmed to control the heating device such that the impact structure is heated to a third temperature higher than a Leidenfrost temperature of the reducing agent.

Description

CROSS REFERENCE TO RELATED APPLICATIONSThis application claims priority to U.S. Provisional Patent Application No. 62 / 756,195, filed Nov. 6, 2018, which is incorporated herein by reference in its entirety and for all purposes.TECHNICAL FIELDThe present application relates generally to systems and methods for reducing formation of reductant deposits in a decomposition reactor of an exhaust aftertreatment system of an internal combustion engine.BACKGROUNDIn internal combustion engines, such as diesel engines, compounds of nitrogen oxide (NO x) may be emitted in the exhaust gas. To reduce NO x- emissions, a reductant may be dosed into the exhaust gas by a dosing system. The reductant may form deposits within the dosing system, such as within a decomposition reactor of the dosing system. Formation of deposits may increase as the temperature of the exhaust gas decreases. The dosing system may become undesirable when an amount of deposits formed within the dosing system is above a threshold.EP 1 748 162 A1 discloses an exhaust gas aftertreatment system comprising an injector for injecting a urea solution into an exhaust gas duct. In the exhaust gas flow of the exhaust gas duct, there are permeable plates in several stages, onto which the urea solution is sprayed in order to prevent them from directly striking a wall of the exhaust gas duct opposite the injector and forming deposits there. When droplets of the urea solution strike the permeable plates located in the hot exhaust gas stream, deposition thereon is avoided by the film boiling effect, reflection of the droplets is promoted and thus uniform dispersion of the urea solution in the exhaust gas stream is made possible.DE 10 2012 004 267 A1 relates to a method for operating an exhaust gas treatment device having an electric heater for heating an exhaust gas stream in the exhaust gas treatment device and having a feed point for feeding an additive into the exhaust gas treatment device, such that the additive impinges on the electric heater.SUMMARYIn one embodiment, an exhaust aftertreatment system includes a decomposition reactor, an injection device, and a processor. The decomposition reactor includes a body, an impingement structure, a guide, and a heater. Exhaust gas may flow through the body. The housing includes an inlet and an outlet. The inlet is configured to receive the exhaust gas at a first temperature. The outlet is configured to expel the exhaust gas at a second temperature that is higher than the first temperature. The impingement structure is disposed within the body between the inlet and the outlet. The impingement structure extends into the body and is located such that the exhaust gas flowing through the body impinges on the impingement structure. The heater is coupled to the impingement structure and is configured to selectively heat the impingement structure. The guide is coupled to the body downstream of the inlet. The guide includes a plurality of guide apertures configured to receive the exhaust gas from the inlet. The injection device is configured to inject reductant into the body. The processor is programmed to control the heater to heat the impingement structure to a third temperature that is higher than a Leidenfrost temperature of the reductant.In another embodiment, an exhaust aftertreatment system includes a decomposition reactor and a processor. The decomposition reactor includes a body, a guide, a flange, a temperature controlled catalyst, and a heater. Exhaust gas may flow through the body. The housing includes an inlet and an outlet. The inlet is configured to receive the exhaust gas. The outlet is configured to selectively expel the exhaust gas. The guide is coupled to the body downstream of the inlet. The guide extends into the body and includes a plurality of guide apertures configured to receive the exhaust gas from the inlet. The flange is coupled to the body downstream of the guide. The inner tube is coupled to the flange and the guide. The inner tube is configured to receive the exhaust gas separately from the inlet and the guide. The inner tube is also configured to provide the exhaust gas through the flange and toward the outlet. The temperature-controlled catalyst is arranged inside the inner tube downstream of the guide. The temperature-controlled catalyst is located such that the exhaust gas passing through the inner pipe toward the outlet impinges on the temperature-controlled catalyst. The heater is coupled to the temperature controlled catalyst and is configured to selectively heat the temperature controlled catalyst. The processor is programmed to control the heater to heat the temperature controlled catalyst to perform hydrolysis of the exhaust gas impinging on the temperature controlled catalyst.In another embodiment, a decomposition reactor for an exhaust aftertreatment system includes an inlet, an outlet, a body, an inner tube, a manifold plate, and a first heater. The inlet is configured to receive an exhaust gas. The outlet is configured to provide the exhaust gas. The body extends between the inlet and the outlet. The inner tube is positioned within the body such that at least a portion of the inner tube is separated from the body by an air gap extending around the inner tube. The inner tube includes an impingement structure positioned proximate the inlet. The distribution plate is coupled to the impingement structure. The first heater is coupled to the manifold plate. The distribution plate separates the first heating device from the impingement structure.BRIEF DESCRIPTION OF THE DRAWINGSThe details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, aspects and advantages of the disclosure will become apparent from the specification, drawings and claims, in which: FIG. 1 is a block diagram of an example exhaust aftertreatment system; FIG. 2 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 3 is a detailed view of the decomposition reactor shown in FIG. 2 ; FIG. 4 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system, according to an embodiment; FIG. 5 is a cross-sectional view of the decomposition reactor shown in FIG. 4 according to another embodiment; FIG. 6 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 7 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 8 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 9 is a rear view of the decomposition reactor shown in FIG. 8, according to an embodiment; FIG. 10 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 11 is a rear view of the decomposition reactor shown in FIG. 10 according to an embodiment; FIG. 12 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 13 is a front view of the decomposition reactor shown in FIG. 12 according to an embodiment; FIG. 14 is a rear view of the decomposition reactor shown in FIG. 12 according to an embodiment; FIG. 15 is a plan view of an inner tube of the decomposition reactor shown in FIG. 12 according to an embodiment; FIG. 16 is a perspective view of an example impingement structure for an exhaust aftertreatment system; FIG. 17 is a cross-sectional view of the impingement structure shown in FIG. 17, according to an embodiment; FIG. 18 is a side cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; FIG. 19 is a cross-sectional view of the decomposition reactor shown in FIG. 18 ; FIG. 20 is a cross-sectional view of an example decomposition reactor of an example exhaust aftertreatment system; and FIG. 21 is a block diagram of a heating strategy for a decomposition reactor of an example exhaust aftertreatment system.It will be appreciated that some or all of the figures are schematic representations for purposes of illustration. The figures are provided for the purpose of illustrating one or more implementations with explicit understanding that they are not used to limit the scope or meaning of the claims.DETAILED DESCRIPTIONDetailed descriptions of various terms regarding and implementations of methods, apparatus, and systems for reducing formation of reductant deposits in a decomposition reactor of an exhaust aftertreatment system for an internal combustion engine follow. The various concepts introduced above and described in detail below may be implemented in any of numerous ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for purposes of illustration.I. OverviewInternal combustion engines (e.g., diesel engines, etc.) produce exhaust gas that is frequently treated by a doser within an exhaust aftertreatment system. Dispensers typically treat exhaust gas using a reducing agent. The reductant is typically introduced by the doser into a tube or die that distributes (e.g., doses, etc.) the reductant into an exhaust stream within an exhaust component.Treatment of exhaust gas with reductant alters the chemical composition of the exhaust gas so that combustion byproducts that are otherwise present in the exhaust gas from an internal combustion engine are reduced. In some areas (e.g., countries, locations, regions, etc.), the amount of combustion byproducts that may be released to the atmosphere (e.g., after being treated by an exhaust aftertreatment system, etc.) is regulated to a threshold amount. As the threshold amount decreases (e.g., by traversing new regulations, etc.), exhaust aftertreatment systems are typically reconfigured to dose exhaust with more reductant. Although this additional reductant may be useful in initially reducing the amount of combustion byproducts, it may form deposits within the exhaust aftertreatment system at a rate that is increased relative to exhaust aftertreatment systems that dose exhaust with less reductant. In addition, deposits are likely to accumulate much faster when the exhaust gas is at a lower temperature than before an internal combustion engine that generates the exhaust gas is operated in the steady state. In addition, introduction of reducing agent into exhaust gas brings about cooling of the exhaust gas. This cooled exhaust gas causes cooling of various surfaces within the exhaust aftertreatment system. This cooling may allow further formation of deposits, as deposits may more likely form at lower temperatures.As deposits accumulate within the exhaust aftertreatment system, the exhaust aftertreatment system may require maintenance or cleaning, or may require the use of a hydrocarbon dosing system, making the exhaust aftertreatment system less desirable (e.g., due to costs associated with maintenance, due to costs associated with cleaning, due to increased fuel consumption caused by the use of a hydrocarbon dosing system, etc.). Accordingly, conventional exhaust aftertreatment systems tend to require more maintenance or cleaning and thus become more and less desirable as more reductant is used because conventional exhaust aftertreatment systems are not capable of reducing accumulation of deposits therein.Implementations herein relate to decomposition reactors that include heaters configured to raise the surface temperature of various components within the decomposition chamber such that the formation of deposits on these components is reduced or substantially eliminated. Some implementations described herein relate to impingement structures (e.g., surfaces cooled by reductant, surfaces disposed adjacent a reductant injector, surfaces downstream of a reductant injector, etc.) that include such heaters and that interact with the exhaust gas to alter the flow of the exhaust gas within the decomposition reactor. The impingement structure may be or may include an impingement surface. Other implementations described herein relate to a temperature controlled catalyst that includes such a heater and that interacts with the exhaust gas to alter the chemical composition thereof while the heater reduces or substantially eliminates the formation of deposits on the temperature controlled catalyst. In this way, the heating device compensates temperature decreases which occur due to the introduction of the reducing agent into the exhaust gas.By incorporating heaters into impingement structures and / or temperature controlled catalysts, an exhaust aftertreatment system may reduce the formation of deposits regardless of other considerations such as mixer design (e.g., distance between a tip of an injector and an impingement structure, angle of an injector with respect to a central axis of an exhaust conduit, spray characteristics of an injector, thickness of an impingement structure, shapes and sizes or internal passes through which exhaust travels, etc.), engine operating characteristics (e.g., flow rate of the exhaust gas, temperature of exhaust gas, etc.), and exhaust aftertreatment system operating characteristics (e.g., reductant dosing rate, temperature of reductant upon injection, etc.). As a result, implementations described herein are substantially more desirable than other systems in which no heaters are incorporated into impingement structures and / or temperature controlled catalysts, as implementations described herein are capable of being used in a wide range of applications without substantial modification.Overview of an Exhaust Aftertreatment SystemFIG. 1 illustrates an exhaust aftertreatment system 100 including an example reductant delivery system 102 for an exhaust system 104. The exhaust aftertreatment system 100 includes a particulate filter (e.g., a diesel particulate filter (DPF) 106, the reductant delivery system 102, a decomposition chamber 108 (e.g., reactor, reactor tube, etc.), an SCR catalyst 110, and a sensor 112.The DPF 106 is configured (e.g., structured, capable, etc.) to remove particulate matter, such as soot, from the exhaust gas flowing in the exhaust system 104. The DPF 106 includes an inlet where the exhaust gas is received and an outlet where the exhaust gas exits after particulate matter has been substantially filtered from the exhaust gas and / or particulate matter has been converted to carbon dioxide. In some implementations, the DPF 106 may be omitted.The decomposition chamber 108 is configured to convert a reductant to ammonia (e.g., NH 3 etc.). The reductant may be, for example, urea, diesel exhaust fluid (DEF), Adblue® a urea water solution (UWS), an aqueous urea solution (e.g., AUS32, AUS 40, etc.), and other similar fluids. The decomposition chamber 108 includes a reductant delivery system 102 having a doser or dosing module 114 configured to dose the reductant into the decomposition chamber 108 (e.g., via an injector). In some implementations, the reductant is injected upstream of the SCR catalyst 110. The reductant droplets then pass through the processes of evaporation, photolysis, and hydrolysis to form gaseous ammonia within the exhaust system 104. The decomposition chamber 108 includes an inlet in fluid communication with the DPF 106 to receive the exhaust gas containing NO x- emissions, and an outlet through which exhaust gas, NO x- emissions, ammonia, and / or reductant flow to the SCR catalyst 110.The decomposition chamber 108 includes the dosing module 114 mounted to the decomposition chamber 108 such that the dosing module 114 may dose the reductant into the exhaust gas flowing into the exhaust system 104. The dosing module 114 may include an isolation device 116 disposed between a portion of the dosing module 114 and the portion of the decomposition chamber 108 on which the dosing module 114 is mounted. The dosing module 114 is fluidly coupled to a reductant source 118 (e.g., fluidly communicable with, etc.). The reductant source 118 may include a plurality of reductant sources 118. The reductant source 118 may be, for example, a diesel exhaust fluid tank that contains Adblue®.A supply unit or reductant pump 120 is used to pressurize the reductant from the reductant source 118 for delivery to the dosing module 114. In some embodiments, the reductant pump 120 is pressure controlled (e.g., controlled to obtain a desired pressure, etc.). The reductant pump 120 includes a filter 122. The filter 122 filters (e.g., load, etc.) the reductant before the reductant is supplied to the internal components (e.g., pistons, vanes, etc.) of the reductant pump 120. For example, the filter 122 may inhibit or prevent the transfer of particulate matter (e.g., solidified reductant, contaminants, etc.) to the internal components of the reductant pump 120. In this manner, the filter 122 may allow for prolonged, desirable operation of the reductant pump 120. In some embodiments, reductant pump 120 is coupled to a chassis of a vehicle associated with exhaust aftertreatment system 100.The dosing module 114 and the reductant pump 120 are also electrically or communicatively coupled to a controller 124. The controller 124 is configured to control the dosing module 114 to dose reductant into the decomposition chamber 108. The controller 124 may also be configured to control the pump 120. The controller 124 may include a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., or combinations thereof. The controller 124 may include memory, which may include, but is not limited to, an electronic, optical, magnetic, or other storage or transmission device capable of providing program instructions to a processor, an ASIC, an FPGA, etc. The memory may include a memory chip, an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a flash memory, or other suitable memory from which the controller 124 may read instructions. The instructions may include code from any suitable programming language.The SCR catalyst 110 is configured to contribute to the reduction of NO x- emissions by accelerating a NO x- reduction process between the ammonia and the NO x of the exhaust gas in diatomic nitrogen, water, and / or carbon dioxide. The SCR catalyst 110 includes an inlet in fluid communication with the decomposition chamber 108 from which exhaust gas and reductant is received, and an outlet in fluid communication with an end of the exhaust system 104.The exhaust system 104 may further include an oxidation catalyst (e.g., a diesel oxidation catalyst (DOC)) in fluid communication with the exhaust system 104 (e.g., downstream of the SCR catalyst 110 or upstream of the DPF 106) to oxidize hydrocarbons and carbon monoxide in the exhaust gas.In some implementations, the DPF 106 may be positioned downstream of the decomposition chamber 108. For example, the DPF 106 and the SCR catalyst 110 may be combined into a single unit. In some implementations, the dosing module 114 may instead be downstream of a turbocharger, upstream of a turbocharger, or integrated into the turbocharger.The sensor 112 may be coupled to the exhaust system 104 to detect a state of the exhaust gas flowing through the exhaust system 104. In some implementations, the sensor 112 may include a portion disposed within the exhaust system 104; for example, a tip of the sensor 112 may extend into a portion of the exhaust system 104. In other implementations, the sensor 112 may receive exhaust gas through another conduit, such as through one or more sample tubes extending out of the exhaust system 104. While the sensor 112 is shown positioned downstream of the SCR catalyst 110, it should be appreciated that the sensor 112 may be positioned at any other position of the exhaust system 104, including upstream of the DPF 106, within the DPF 106, between the DPF 106 and the decomposition chamber 108, within the decomposition chamber 108, between the decomposition chamber 108 and the SCR catalyst 110, within the SCR catalyst 110, or downstream of the SCR catalyst 110. Additionally, two or more sensors 112 may be utilized to detect a condition of the exhaust gas, such as two, three, four, five, or six sensors 112, with each sensor 112 located at one of the aforementioned positions of the exhaust system 104. However, in other embodiments, the reductant delivery system 102 does not include the sensor 112.In some embodiments, the reductant delivery system 102 also includes an air pump 128. The air pump 128 draws air from an air source 130 (e.g., air inlet, etc.). Additionally, the air pump 128 provides the air to the dosing module 114 via a conduit. The dosing module 114 is configured to mix the air and reductant into an air-reductant mixture. The dosing module 114 is further configured to deliver the air-reductant mixture into the decomposition chamber 108. However, in other embodiments, the reductant delivery system 102 does not include the air pump 128 or the air source 130, and air is not mixed with the reductant in the dosing module 114.III. Exemplary Exhaust Gas Aftertreatment System Having Heating Device and Impingement StructuresFIG. 2 illustrates a cross-sectional view of an exhaust aftertreatment system 200 (e.g., a UL2 exhaust aftertreatment system, an emission exhaust aftertreatment system, etc.). The exhaust aftertreatment system 200 may serve as the exhaust aftertreatment system 100 described above. The exhaust aftertreatment system 200 includes a decomposition reactor 202. The decomposition reactor 202 may serve as the decomposition chamber 108 described above. The decomposition reactor 202 includes a body 203 (e.g., frame, shell, etc.) having an inlet 204 (e.g., inlet, inlet, etc.) and an outlet 206 (e.g., outlet, outlet, etc.). The inlet 204 is configured to receive the exhaust gas from an upstream component of the exhaust aftertreatment system 200, such as a DPF similar to the DPF 106 described above. The outlet 206 is configured to provide a mixture of the exhaust gas and reductant (e.g., treated exhaust gas, etc.) to a downstream component of the exhaust aftertreatment system 200, such as a catalyst similar to the SCR catalyst 110 described above.The exhaust aftertreatment system 200 also includes a dosing module 208. The dosing module 208 may serve as the dosing module 114 described above. The dosing module 208 is configured to receive reductant from a reductant pump, similar to the reductant pump 120 that draws reductant from a reductant supply, similar to the reductant source 118. In some embodiments, the dosing module 208 also receives air from an air pump, similar to the previously described air pump 128, which receives air from an air supply, similar to the air source 130.The dosing module 208 includes an injector 210 (e.g., side mount injector, reductant injector, etc.) coupled to the body 203. The injection device 210 is configured to inject reductant from the dosing module 208 into the decomposition reactor 202 such that the exhaust gas within the decomposition reactor 202 may be treated with the reductant. The injector 210 is not simply a pipe that directs reductant into the center of the decomposition reactor 202 (e.g., for deposition on a catalyst, etc.). Instead, the injector 210 is configured to inject reductant into the exhaust gas.The amount of reductant dosed into the exhaust gas refers to a threshold amount of combustion byproducts discharged to the atmosphere by the exhaust aftertreatment system 200. In some applications, the exhaust aftertreatment system 200 is controlled to dose the exhaust with a target amount of reductant such that a target amount of combustion byproducts less than the threshold amount of combustion byproducts is delivered from the exhaust aftertreatment system 200.Reductant may form deposits in conventional exhaust aftertreatment systems. These deposits may reduce the efficiency of the exhaust aftertreatment system. However, the exhaust aftertreatment system 200 includes a heater 212 (e.g., electrical heater, resistive heater, etc.) that may reduce or substantially prevent the formation of deposits within the decomposition reactor 202 (e.g., the formation of deposits may be limited to amounts less than 5% of the amount of deposits formed in conventional exhaust aftertreatment systems using the same amount of reductant), thereby causing the exhaust aftertreatment system 200 to operate more efficiently than conventional exhaust aftertreatment systems. The heater 212 provides additional heat to the exhaust gas that could not otherwise be provided.The exhaust aftertreatment system 200 is particularly more desirable in applications where relatively large amounts of reductant are used to treat the exhaust gas, such as in applications where regulations are set that drastically limit the amount of combustion byproducts an internal combustion engine is permitted to deliver. In such applications, conventional exhaust aftertreatment systems may become rapidly less desirable due to rapid deposit formation that occurs because a large amount of reductant is used and there is no mechanism to prevent deposit formation, or due to increased fuel consumption that occurs because a hydrocarbon dosing system is used to dose fuel into the exhaust gases. Additionally, the exhaust aftertreatment system 200 is more desirable in applications where exhaust gas recirculation is not utilized. In such applications, conventional exhaust aftertreatment systems may emit relatively high levels of combustion byproducts, as exhaust gas recirculation is not utilized. These relatively high levels of combustion byproducts that would otherwise be released may be dramatically decreased by the exhaust aftertreatment system 200.The advantages of the exhaust aftertreatment system 200 as compared to a conventional exhaust aftertreatment system are particularly present when treating exhaust gas at relatively low temperature, such as exhaust gas emitted during engine warm-up. When conventional exhaust aftertreatment systems treat the same exhaust gas at a relatively low temperature, the heating of the reductant by the exhaust gas is decreased, thereby increasing deposit formation.Rather than just heating the exhaust gas directly and indirectly heating surfaces within the decomposition reactor 202 (e.g., through interaction with the heated exhaust gas, etc.), the heater 212 is configured to directly heat the impingement structures 214 of the decomposition reactor 202. The impingement structures 214 are surfaces within the decomposition reactor 202 that are coupled to the body 203 and are in close proximity (e.g., downstream, below, etc.) to the injector 210, where deposits are more likely to form if the heater 212 is absent. In various embodiments, the impingement structures 214 are surfaces of splash plates, surfaces of swirl plates, surfaces of swirl devices, surfaces of blenders, and other similar surfaces within the decomposition reactor 202.In various embodiments, the heater 212 does not continuously heat the impingement structures 214 of the decomposition reactor 202. Instead, the heater 212 selectively heats the impingement structures 214. For example, if a difference between a temperature of the exhaust gases at the inlet 204 and a temperature of the exhaust gases at the outlet 206 is above a threshold, the heater 212 may not heat the impingement structures 214.In some embodiments, the impingement structures 214 extend below the injector 210 and substantially prevent reductant from contacting the decomposition reactor 202. For example, the impingement structures 214 may be a plurality of overlapped plates that allow exhaust flow therethrough but are arranged to prevent reductant from being sprayed downwardly from the injector 210 and onto the decomposition reactor 202.The impingement structures 214 may be configured to have a minimum heat capacity (e.g., heat capacity, etc.). For example, the impingement structures 214 may be thin, small, and numerous (e.g., a plurality of thin and small plates, etc.). In this way, the impingement structures 214 may be rapidly heated, such that minimal pre-heating of the impingement structures 214 (e.g., before reductant may be dosed into the exhaust, etc.) is necessary. Such configurations of the impingement structures 214 maximize the amount of exhaust gas that can be treated with reductant while reducing or substantially preventing formation of deposits by the impingement structures 214.The impingement structures 214 may have a higher than normal surface roughness (e.g., a surface roughness greater than a polished surface, etc.) to minimize formation of deposits thereon. For example, the landing structures 214 may be textured. The surface roughness of the impingement structures 214 in such embodiments causes droplets to break down into smaller droplets as they approach the impingement structures. These smaller droplets decompose more quickly than larger droplets, thereby decreasing the likelihood of deposit formation. However, the surface roughness of the impingement structures 214 may also be maintained below a threshold surface roughness where fluid movement along the impingement structures 214 is negatively affected and where heat transfer through the impingement structures 214 is negatively affected.FIG. 3 illustrates a detailed view of a cross-section of an example impingement structure 214. In the embodiment shown in FIG. 3, the heater 212 is disposed within the impingement structure 214 such that a portion of the impingement structure 214 extends above and above the heater 212. In other embodiments, the heater 212 is embedded within the impingement structure 214 such that the heater 212 is exposed and not covered by the impingement structure 214. In other embodiments, the impingement structure 214 is the heater 212 itself (e.g., the heater 212 is constructed and constructed to be the impingement structure 214, etc.).As shown in FIG. 3, the heater 212 heats the impingement structure 214 such that a vapor layer 300 is formed between an outer surface 302 of the impingement structure 214 and a droplet 304 of reductant. It should be appreciated that the outer surface 302 may be any combination of the impingement structure 214 and the heater 212, depending on whether the heater 212 is covered, partially covered, or not covered by the impingement structure 214.The vapor layer 300 is formed from the droplet 304 via the Leidenfrost effect. The Leidenfrost effect occurs because a temperature T Face of the outer surface 302 is higher than a Leidenfrost temperature T L( e.g., a film boiling temperature, a Leidenfrost point, etc.) of the droplet 304, causing a portion of the droplet 304 to vaporize and separate the droplet 304 from the outer surface 302. In this manner, the outer surface 302 is separated from the droplets 304 such that formation of deposits on the outer surface 302 is reduced or substantially prevented.The vapor layer 300 has a thickness related to the temperature T Face. The temperature T Face refers to a temperature of the heater 212, a thermal conductivity of the heater 212, a thermal conductivity of the impingement structure 214, and a thickness of the impingement structure 214 near the heater 212. The Leidenfrost temperature T L refers to a configuration of the exhaust aftertreatment system 200, a reductant type, a temperature of the droplet 304, a Weber number of the droplet 304 (e.g., based on a mass of the droplet 304, a velocity of the droplet 304, a density of the droplet 304, and a surface tension of the droplet 304, etc.), a pressure within the decomposition reactor 202, a flow rate (e.g., volume flow rate, mass flow rate, etc.) of the exhaust gas through the decomposition reactor, a material of the outer surface 302, a surface roughness of the outer surface 302, and thermal properties (e.g., thermal conductivity, thickness, etc.) of the outer surface 302. Tables 1 and 2 represent temperature T L according to various embodiments. In Tables 1 and 2, the polished surface roughness is less than the unpolished surface roughness. By increasing the surface roughness (e.g., in unpolished embodiments), the temperature T L typically decreases because the surface roughness causes a corresponding roughness in the vapor layers 300, may cause the droplets 304 to decompose, thereby facilitating decomposition of the droplets 304 into the exhaust gas. Table 1: Temperature T L for droplets 304, wherein the outer surface 302 is polished and unpolished when the exhaust aftertreatment system 200 is a UL2 exhaust aftertreatment system. Table 1: Temperature TL for droplets 304, wherein the outer surface 302 is polished and unpolished when the exhaust aftertreatment system 200 is a UL2 exhaust aftertreatment system.Temperature T L [ °C]123,3130,3137,3121128,8137,8Table 2: Temperature T L for droplets 304, wherein the outer surface 302 is polished and unpolished when the exhaust aftertreatment system 200 is an Emitec exhaust aftertreatment system.Table 2: Temperature TL for droplets 304, wherein the outer surface 302 is polished and unpolished when the exhaust aftertreatment system 200 is an Emitec exhaust aftertreatment system.Temperature T L [ °C]144,2147,4150,7141145,6150,2In some embodiments, the impingement structure 214 and / or the injection device 210 is configured to enable increased impact energy of the droplets 304 on the impingement structure 214 or enable a higher Weber number. In this way, the impingement structure 214 and / or the injector 210 may promote splashing, disintegration of the droplets 304, and disintegration of the droplets 304, while minimizing formation of deposits. When the impingement structure 214 and / or the injection device 210 are configured in this manner, the temperature T L may increase, requiring a corresponding increase in the temperature T Face.In addition to being maintained above the temperature T L the heater 212 is controlled so that the temperature T Face is maintained below an oxidizing temperature T O of the reducing agent. The temperature T O is a temperature above which the reducing agent oxidizes. Oxidized reductant may negatively impact an performance of an exhaust aftertreatment system, such as by reducing functionality of an SCR catalyst, such as the SCR catalyst 110, positioned downstream of the heater 212.FIG. 4 illustrates decomposition reactor 202 in an example embodiment. The previously described heater 212 and impingement structure 214 are shown in FIG. 4 as heater 400 and impingement structures 402. The impingement structures 402 define a plurality of apertures (e.g., holes, channels, openings, etc.) therebetween. The exhaust gas can pass freely through these apertures, but is guided through the impingement structures 402. In this way, the impingement structures 402 may serve as, for example, flow rectifiers such that the flow of the exhaust gas is rectified prior to flowing from the decomposition reactor 202.Each of the impingement structures 402 integrally includes one of the heaters 400 (e.g., at a trailing edge of the impingement structure 402, at an upstream edge of the impingement structure 402, etc.) and serves to heat the associated impingement structure 402. This arrangement may allow for rapid heating of the impingement structures 402 as the heaters 400 are distributed and located.In various embodiments, the heaters 400 are electrical heaters (e.g., resistive heaters, heating elements, etc.) and not burners (e.g., combustion heaters, etc.). As a result, the heaters 400 themselves do not have direct discharges (e.g., combustion byproducts, etc.) into the exhaust gas.The heaters 400 are connected via leads (e.g., electrical leads, etc.) to a power source (e.g., an electrical system of an internal combustion engine in communication with the exhaust aftertreatment system 200, etc.). The lines are routed from outside the decomposition reactor 202, into the decomposition reactor 202, and to the heater 400. In some embodiments, the conduits are routed through the decomposition reactor 202 to a location proximate the heaters 400 and through the impingement structures 402 to the heaters 400.In various embodiments, the decomposition reactor 202 includes a vortex mixer 404 (e.g., mixing plate, paddle mixer, co-vortex mixer, counter-vortex mixer, etc.) coupled to the body 203. The vortex mixer 404 is positioned downstream of the impingement structures 402 and upstream of the outlet 206. The vortex mixer 404 is configured to allow mixing between the exhaust gas flowing over and between the impingement structures 402. The vortex mixer 404 may be configured such that the decomposition reactor 202 has a target back pressure and a target mixing length such that the decomposition reactor 202 is customized for a target application. In other embodiments, the decomposition reactor 202 does not include a vortex mixer 404.FIG. 5 illustrates decomposition reactor 202 in another exemplary embodiment. The heater 212 and impingement structure 214 described above are shown in FIG. 5 as the heater 400 and impingement structures 402, while the injector 210 is shown as an injector 500. The injector 500 extends into the decomposition reactor 202 such that reductant is sprayed from the injector 500 proximate a central axis (e.g., central axis, etc.) of the decomposition reactor 202. In various embodiments, the injection device 500 is a metering jet tube.FIG. 6 illustrates decomposition reactor 202 in yet another exemplary embodiment. The previously described heater 212 and impingement structure 214 are shown in FIG. 6 as heater 600 and impingement structures 602. The impingement structures 602 define a plurality of apertures (e.g., holes, channels, openings, etc.) therebetween. The exhaust gas can pass freely through these apertures, but is guided by the impingement structures 602. In this way, the impingement structures 602 may serve as, for example, flow rectifiers such that the flow of the exhaust gas is rectified prior to flowing from the decomposition reactor 202.Each of the impingement structures 602 integrally has one of the heaters 600 therein (e.g., at a leading edge of the impingement structure 602, at an upstream edge of the impingement structure 602, etc.) and serves to heat the associated impingement structure 602. This arrangement may allow for rapid heating of the impingement structures 602 because the heaters 600 are distributed and located. In addition, the impingement structures 602 are offset and arranged below the injection device 210. This arrangement substantially prevents reductant from being sprayed directly onto the body 203 by the injector 210, thereby minimizing formation of deposits on the body 203. Instead, the reductant flows toward the impingement structures 602 and is either entrained in the exhaust gas or approaches the impingement structures 602 for decomposition or entrainment in the exhaust gas.In some embodiments, decomposition reactor 202 also includes a vortex mixer 604 coupled to body 203. The vortex mixer 604 serves as the previously described vortex mixer 404. In other embodiments, the decomposition reactor 202 does not include a vortex mixer 604.FIG. 7 illustrates the decomposition reactor 202 in yet another exemplary embodiment. The decomposition reactor 202 includes an inner tube 700 (e.g., blender tube, etc.) positioned therein. The inner tube 700 is centered on a central axis substantially parallel to a central axis of the decomposition reactor 202. The inner tube 700 is configured to receive the exhaust gas directly from the inlet 204 (e.g., via an aperture in a front surface of the inner tube 700, etc.) and provide the exhaust gas to the outlet 206. The inner tube 700 is coupled to the decomposition reactor 202 via a flange 702. The flange 702 may be integral with the inner tube 700 and / or the body 203, and / or may be coupled (e.g., attached, bonded, welded, etc.) to the inner tube 700 and / or the body 203. In some embodiments, the flange 702 facilitates the passage of the exhaust gas therethrough such that a portion of the exhaust gas may flow from the inlet 204 to the outlet 206 without flowing through the inner tube 700. In other embodiments, the flange 702 is sealed from the decomposition reactor 202 so as to prevent the exhaust gas from bypassing the inner tube 700, and is only capable of flowing from the inlet 204 to the outlet 206 via the inner tube 700.The decomposition reactor 202 also includes a guide 704 (e.g., exhaust support, shield, cone, etc.). The guide 704 is coupled to the inner tube 700 and positioned around the injector 210. In some embodiments, the guide 704 is coupled to the body 203. In other embodiments, the guide 704 is coupled to the injection device 210. The guide 704 is configured to receive the reductant from the injector 210 and introduce the reductant into the inner tube 700. The guide 704 includes a plurality of guide apertures 705 (e.g., holes, apertures, etc.) configured to receive the exhaust gas such that the received exhaust gas is used to drive the reductant from the injector 210 into the inner tube 700. The guide apertures 705 may be disposed on an upstream surface of the guide 704, for example.The heater 212 and impingement structure 214 described above are shown in FIG. 7 as heater 706 and impingement structures 708. The impingement structures 708 are at least partially disposed within the guide 704 such that the exhaust gas and reductant are directed through the impingement structures 708 when the exhaust gas and reductant are driven into the inner tube 700. The impingement structures 708 may be arranged to swirl the exhaust gas and the reductant to enable mixing of the exhaust gas and the reductant.Each of the impingement structures 708 integrally has one of the heaters 706 therein (e.g., on a central portion of the impingement structure 708, etc.) and serves to heat the associated impingement structure 708. This arrangement may allow for rapid heating of the impingement structures 708 because the heaters 706 are distributed and located. In addition, the impingement structures 708 are offset and disposed below the injection device 210. This arrangement substantially prevents reductant from being sprayed directly onto the inner tube 700 or the guide 704 by the injector 210, thereby minimizing formation of deposits on the inner tube 700 and / or the guide 704. Instead, the reductant flows toward the impingement structures 708 and is either entrained in the exhaust gas or approaches the impingement structures 708 for decomposition or entrainment in the exhaust gas.The guide apertures 705 may be configured to receive a target amount of exhaust gas through the guide 704, where the target amount is a minimum amount of exhaust gas necessary to drive the reductant from the injector 210 into the inner tube 700. By using only the minimum amount of exhaust gas to drive the reductant into the inner tube 700, only a minimum amount of heating by the heaters 706 is necessary, thereby reducing the power consumption of the heaters 706 and making the exhaust aftertreatment system 200 more desirable.The heaters 706 are connected via leads (e.g., electrical leads, etc.) to a power source (e.g., an electrical system of an internal combustion engine in communication with the exhaust aftertreatment system 200, etc.). The lines are routed from outside the decomposition reactor 202, into the decomposition reactor 202, and to the heaters 706. In some embodiments, the conduits are routed through the decomposition reactor 202 to a location proximate the guide 704, along a downstream surface of the guide 704, through the guide 704, and through the impingement structures 708 to the heaters 706.In some embodiments, decomposition reactor 202 also includes a vortex mixer 710 coupled to body 203. The vortex mixer 710 serves as the previously described vortex mixer 404. In other embodiments, the decomposition reactor 202 does not include a vortex mixer 710.FIG. 8 illustrates the decomposition reactor 202 in yet another exemplary embodiment. The inner tube 700, flange 702, guide 704, guide apertures 705, heater 212, and impingement structure 214 described above are shown in FIG. 8 as an inner tube 800, flange 802, guide 804, guide apertures 805, heater 806, and impingement structures 808. The inner tube 800 includes a downstream end 810. The downstream end 810 provides a flow constriction for the exhaust gas flowing from the inner tube 800 into the decomposition reactor 202.The impingement structures 808 are at least partially disposed within the downstream end 810 such that the exhaust gas and reductant are directed through the impingement structures 808 as the exhaust gas and reductant are forced out of the inner tube 800. The impingement structures 808 define a plurality of apertures (e.g., holes, channels, openings, etc.) therebetween. The exhaust gas may pass freely through these apertures, but is guided by the impingement structures 808. In this way, the impingement structures 808 may be arranged, for example, to swirl the exhaust gas and the reductant to enable mixing of the exhaust gas and the reductant. In other applications, the impingement structures 808 may serve as a flow rectifier such that the flow of the exhaust gas is rectified prior to flowing from the decomposition reactor 202.Each of the impingement structures 808 integrally has a portion of the heater 806 therein (e.g., in a central portion of each of the impingement structures 808, etc.). The heater 806 is a continuous member that extends spirally within the inner tube 800 and / or the downstream end 810 such that the heater 806 is capable of being installed within each of the impingement structures 808. In this way, the heater 806 may serve to heat all the impingement structures 808 simultaneously. This arrangement substantially prevents reductant from forming deposits on the impingement structures 808. Instead, the reductant is mixed with the exhaust gas through the impingement structures 808.The guide apertures 805 may be configured to receive a target amount of exhaust gas through the guide 804, where the target amount is a minimum amount of exhaust gas necessary to drive the reductant from the injector 210 into the inner tube 800. By using only the minimum amount of exhaust gas to drive the reductant into the inner tube 800, only a minimum amount of heating by the heaters 806 is necessary, thereby reducing power consumption of the heaters 806 and making the exhaust aftertreatment system 200 more desirable.The heaters 806 are connected via leads (e.g., electrical leads, etc.) to a power source (e.g., an electrical system of an internal combustion engine in communication with the exhaust aftertreatment system 200, etc.). The lines are routed from outside the decomposition reactor 202, into the decomposition reactor 202, and to the heaters 806. In some embodiments, the conduits are routed through the decomposition reactor 202 to a location proximate the guide 804, along a downstream surface of the guide 804, along an upper surface of the inner tube 800, through the inner tube 800, and through the impingement structures 808 to the heaters 806.In some embodiments, decomposition reactor 202 also includes a vortex mixer 812 coupled to body 203. The vortex mixer 812 serves as the previously described vortex mixer 404. In other embodiments, the decomposition reactor 202 does not include a vortex mixer 812.FIG. 9 illustrates a rear view of the decomposition reactor 202 according to the embodiment shown in FIG. 8 from the outlet 206 towards the inlet 204 and without the vortex mixer 812 shown. As shown in FIG. 9, the impingement structures 808 are coupled to the heater 806 and are helically disposed about a central axis of the inner tube 800. In FIG. 9, the heater 806 is shown coupled not to the central portion described in FIG. 8, but to each of the impingement structures 808 proximate a downstream end of the impingement structures. As shown in FIG. 9, because the heater 806 is continuously coupled to each of the impingement structures 808, it extends between adjacent impingement structures 808. In addition to the impingement structures 808, the heater 806 is configured to allow reductant distribution via the Leidenfrost effect as described with respect to the impingement structures 808 such that these spanning portions of the heater 806 assist the impingement structures 808 in reducing or substantially preventing formation of deposits in the decomposition reactor 202.In other embodiments, heater 806 may instead be replaced with multiple separate heaters, each located on an impingement structure 808. In still other embodiments, the heater 806 may be replaced with multiple separate heaters, each coupled to two or more impingement structures 808. For example, the decomposition reactor 202 may include two heaters 806, each coupled to half of the impingement structures 808. The heater 806 may be arranged in one or more spirals, helices (e.g., a double helix, etc.), and other similar shapes. It should be understood that the description of the heater 806, the heaters 706, and any other heater disposed at least partially within the inner tube 700 applies equally to some embodiments of the heaters 600, the heaters 400, and other heaters used without the inner tube 700. It should also be understood that the description of the heaters 600, heaters 400, and other heaters used without the inner tube 700 applies equally to some embodiments of the heater 806, heaters 706, and any other heater disposed at least partially within the inner tube 700.In various embodiments, the decomposition reactor 202 is configured to minimize heat transfer therethrough such that the additional heat generated by the heaters (e.g., heaters 400, heaters 600, heaters 706, heater 806, etc.) is retained by the decomposition reactor 202, thereby providing the exhaust gas and reductant of the downstream component of the exhaust aftertreatment system 200, such as an SCR catalyst, with the additional heat introduced by the heaters. This additional heat may allow higher efficiencies to be achieved by the exhaust aftertreatment system 200. The decomposition reactor 202 may be configured to minimize heat transfer by wrapping insulation around the decomposition reactor 202 as well as constructing the decomposition reactor 202 using different materials (e.g., materials with lower thermal conductivity coefficients, etc.).FIGS. 10 and 11 illustrate the decomposition reactor 202 in still another exemplary embodiment. The inner tube 700, flange 702, heater 212, and impingement structure 214 described above are shown in FIGS. 10 and 11 as an inner tube 1000, flange 1002, heater 1004, and impingement structure 1006. As shown in FIGS. 10 and 11, decomposition reactor 202 does not include a guide (e.g., a guide similar to guide 704, etc.) or guide apertures (e.g., similar to guide apertures 705, etc.). However, it should be appreciated that decomposition reactor 202 may include a guide and guide apertures as shown in FIGS. 10 and 11 in some embodiments.The inner tube 1000 includes a downstream end 1008. The inner tube 1000 includes a plurality of fins 1010. Each of the vanes 1010 is at least partially disposed within the downstream end 1008 such that the exhaust gas and reductant are directed through the vanes 1010 as the exhaust gas and reductant are forced out of the inner tube 1000. The fins 1010 define a plurality of apertures (e.g., holes, channels, openings, etc.) therebetween. The exhaust gas can pass freely through these apertures, but is guided through the lamellae 1010. In this way, the vanes 1010 may be arranged, for example, to swirl the exhaust gas and the reductant to allow mixing of the exhaust gas and the reductant. In other applications, the fins 1010 may serve as a flow rectifier such that the flow of the exhaust gas is rectified prior to flowing from the decomposition reactor 202.Rather than being the fins 1010, the impingement structure 1006 is a portion of the inner tube 1000 (e.g., a wall segment of the inner tube 1000, etc.). The impingement structure 1006 is disposed proximate an upstream end 1010 of the inner tube 1000. The upstream end 1010 is opposite the downstream end 1008.The impingement structure 1006 extends around the inner tube 1000. In various embodiments, the impingement structure 1006 extends along more than half of a perimeter of the inner tube 1000. For example, in some embodiments, the impingement structure 1006 extends along 75% of the perimeter of the inner tube 1000. In some embodiments, the impingement structure 1006 extends around at least the entire perimeter of the inner tube 1000.The impingement structures 1006 are at least partially opposite an injector aperture 1011 configured to receive the injector 210. For example, the injector aperture 1011 may be disposed in an upper portion of the inner tube 1000, and the impingement structure 1006 may extend around a lower portion of the inner tube 1000 (e.g., opposite the upper portion of the inner tube 1000).The exhaust aftertreatment system 200 also includes a manifold plate 1012. The manifold plate 1012 is coupled to the impingement structure 1006 and the heater 1004. As a result, the manifold plate 1012 and the heater 1004 extend at least partially around the inner tube 1000. The heater 1004 is coupled to the manifold plate 1012. In some embodiments, the heater 1004 is coupled to both the manifold plate 1012 and the impingement structure 1006. The manifold plate 1012 extends at least partially between the heater 1004 and the impingement structure 1006. This arrangement substantially prevents reductant sprayed by the injector 210 from forming deposits on the impingement structure 1006.The manifold plate 1012 absorbs the heat provided by the heater 1004 and serves to increase uniformity of the heat provided to the impingement structure 1006 by the heater 1004. For example, the manifold plate 1012 may smooth a discontinuity in the heat provided by different heating elements (e.g., leads, plates, etc.) within the heater 1004 by spanning over the different heating elements, absorbing heat provided by the different heating elements, and distributing that heat over the entire manifold plate 1012 (e.g., over a portion of the manifold plate 1012 that extends between the different heating elements, etc.). In various embodiments, the manifold plate 1012 is constructed from a material having a higher thermal conductivity than a thermal conductivity of the impingement structure 1006. In some embodiments, the manifold plate 1012 is constructed from copper. In one embodiment, heater 1004 is a 2500 watt (2500 W) heater. The heater 1004 may be defined by a maximum operating temperature (e.g., a temperature above which the heater 1004 is unable to operate desirably, etc.). In some embodiments, the heater 1004 is defined by a maximum operating temperature of 760 degrees Celsius (° C.).In addition to the impingement structure 1006, the heater 1004 is configured to enable reductant distribution via the Leidenfrost effect as described with respect to the impingement structure 1004 such that these spanning portions of the heater 1004 assist the impingement structure 1004 in reducing or substantially preventing formation of deposits in the decomposition reactor 202.The heater 1004 is connected via leads (e.g., electrical leads, etc.) to a power source (e.g., an electrical system of an internal combustion engine in communication with the exhaust aftertreatment system 200, etc.). The lines are routed from outside the decomposition reactor 202, into the decomposition reactor 202, and to the heater 1004.The heat Δ that must be provided by the heater 1004 to obtain a particular surface temperature σ of the impingement structure 1006 may be modeled according to various equations. These equations are derived by comparing σ at different times between the time when reductant is provided by the injector 210 and one second after the time when reductant is provided by the injector 210 (e.g., at the time when reductant is provided by the injector 210, 0.5 seconds after the time when reductant is provided by the injector 210, and 1 second after the time when reductant is provided by the injector 210, etc.). The equations do not take into account a distance between the injector 210 (e.g., a tip of the injector) and the impingement structure 1006, do not take into account spray characteristics of the reductant provided by the injector 210, do not take into account heat loss from the heater 1004 to the exhaust, and assume that all reductant impinges on the impingement structure 1006. These equations depend on the thickness of the impingement structure 1006, the area of the impingement structure 1006, the initial temperature of the reductant provided by the injector 210, and a diameter of the inner tube 1000. In a impingement structure 1006 made of steel having a thickness of 1.39 millimeters (mm), an area of 645.16 mm 2, reductant having an initial temperature of 25° C., and an inner tube 1000 having a diameter of 266.7 mm, the Δ is in kilowatts (kW) at a σin ° C.: orFIG. 11 illustrates a rear view of the decomposition reactor 202 according to the embodiment shown in FIG. 10 from the outlet 206 towards the inlet 204 and without the injection device 210 shown.In other embodiments, heater 1004 may instead be replaced with multiple separate heaters, each located at a portion of impingement structure 1006. For example, the decomposition reactor 202 may include two heaters 1004, each coupled to half of the impingement structure 1006. The heater 1004 may be arranged in one or more spirals, helices (e.g., a double helix, etc.), and other similar shapes. It should be understood that the description of the heater 1004, heater 806, heaters 706, and any other heater disposed at least partially within or around an inner tube applies equally to some embodiments of the heaters 600, heaters 400, and other heaters used without the inner tube 700. It should also be understood that the description of the heaters 600, heaters 400, and other heaters used without the inner tube 700 applies equally to some embodiments of the heater 1004, heater 806, heaters 706, and any other heater disposed at least partially within or around an inner tube.In various embodiments, the decomposition reactor 202 is configured to minimize heat transfer therethrough such that the additional heat generated by the heaters (e.g., heaters 400, heaters 600, heaters 706, heater 806, heater 1004, etc.) is retained by the decomposition reactor 202, thereby providing the exhaust gas and reductant of the downstream component of the exhaust aftertreatment system 200, such as an SCR catalyst, with the additional heat introduced by the heaters. This additional heat may allow higher efficiencies to be achieved by the exhaust aftertreatment system 200. The decomposition reactor 202 may be configured to minimize heat transfer by wrapping insulation around the decomposition reactor 202 as well as constructing the decomposition reactor 202 using different materials (e.g., materials with lower thermal conductivity coefficients, etc.).FIGS. 12-15 illustrate decomposition reactor 202 in yet another exemplary embodiment. The inner tube 700, heater 212, and impingement structure 214 described above are shown in FIGS. 12-15 as an inner tube 1200, a plurality of heaters 1202, and an impingement structure 1204. As shown in FIGS. 12-15, decomposition reactor 202 does not include a guide (e.g., a guide similar to guide 704, etc.), guide apertures (e.g., similar to guide apertures 705, etc.), or fins (e.g., similar to fins 1010, etc.). However, it should be appreciated that decomposition reactor 202 may include a guide, guide aperture, and / or fins in some embodiments, as shown in FIGS. 12-15.The inner tube 1200 includes a downstream end 1206 and an upstream end 1208 opposite the downstream end 1206. The impingement structure 1204 is disposed proximate the upstream end 1208 (e.g., the impingement structure 1204 is closer to the upstream end 1208 than to the downstream end 1206).The exhaust aftertreatment system 200 also includes a mixing plate 1209. The mixing plate 1209 is disposed within and coupled to the inner tube 1000. In this manner, the mixing plate 1209 extends over the inner tube 1000. The mixing plate 1209 is located between the impingement structure 1204 and the downstream end 1206. In various embodiments, the mixing plate 1209 is proximate the downstream end 1206 (e.g., the mixing plate 1209 is closer to the downstream end 1206 than to the upstream end 1206).The mixing plate 1209 includes a plurality of mixing plate apertures 1210 and a mixing plate channel 1212. The exhaust gas may flow through the mixing plate 1209 via one of the mixing plate apertures 1210. In addition, the exhaust gas may be directed through the mixing plate to the mixing plate passage 1212 and flow through the mixing plate 1209 via the mixing plate passage 1212. The mixing plate passage 1212 is configured to cause the exhaust gas exiting the mixing plate passage 1212 to swirl downstream of the mixing plate 1209. The mixing plate apertures 1210 are configured to reduce backpressure of the exhaust aftertreatment system 200 by allowing a portion of the exhaust gas to bypass the mixing plate passage 1212.Instead of being the mixing plate 1209, the impingement structure 1204 is a portion of the inner tube 1200 (e.g., a wall segment of the inner tube 1200, etc.). The impingement structure 1204 extends around the inner tube 1200. In various embodiments, the impingement structure 1204 extends along about half of a perimeter of the inner tube 1200.The impingement structures 1204 are at least partially opposite an injector aperture 1211 configured to receive the injector 210. For example, the injector aperture 1211 may be disposed in an upper portion of the inner tube 1200, and the impingement structure 1204 may extend around a lower portion of the inner tube 1200 (e.g., opposite the upper portion of the inner tube 1200).The exhaust aftertreatment system 200 also includes a manifold plate 1214. The manifold plate 1214 is coupled to the impingement structure 1204 and the heaters 1202. As a result, the manifold plate 1214 and the heaters 1202 extend at least partially around the inner tube 1200. The heaters 1202 are each coupled to the manifold plate 1214. In some embodiments, the heaters 1202 are each coupled to both the manifold plate 1214 and the impingement structure 1204. The manifold plate 1214 extends at least partially between the heaters 1202 and the impingement structure 1204. This arrangement substantially prevents reductant sprayed by the injector 210 from forming deposits on the impingement structure 1204.The manifold plate 1214 absorbs the heat provided by the heaters 1202 and serves to increase uniformity of the heat provided to the impingement structure 1204 by the heaters 1202. For example, the manifold plate 1214 may smooth a discontinuity of the heat provided by different heaters 1202 by spanning over the different heaters 1202, absorbing the heat provided by the different heaters 1202, and distributing that heat over the entire manifold plate 1214 (e.g., over a portion of the manifold plate 1214 extending between the different heaters 1202, etc.). In various embodiments, the manifold plate 1214 is constructed from a material having a higher thermal conductivity than a thermal conductivity of the impingement structure 1204.In addition to the impingement structure 1204, the heaters 1202 are configured to enable reductant distribution via the Leidenfrost effect as described with respect to the impingement structure 1204 such that these spanning portions of the heaters 1202 assist the impingement structure 1204 in reducing or substantially preventing formation of deposits in the decomposition reactor 202.The heaters 1202 are connected via leads (e.g., electrical leads, etc.) to a power source (e.g., an electrical system of an internal combustion engine in communication with the exhaust aftertreatment system 200, etc.). The lines are routed from outside the decomposition reactor 202, into the decomposition reactor 202 and to the heaters 1202.FIG. 13 illustrates a front view of the decomposition reactor 202 according to the embodiment shown in FIG. 12 from the inlet 204 towards the outlet 206. FIG. 14 illustrates a rear view of the decomposition reactor 202 according to the embodiment shown in FIG. 12 from the outlet 206 toward the inlet 204. As shown in FIG. 14, the heaters 1202 are spirally arranged around a central axis of the inner tube 1200. As shown in FIG. 14, since the manifold plate 1214 is continuously coupled to each of the heaters 1202, it extends between adjacent heaters 1202. In addition to the impingement structures 1204, the heaters 1202 are configured to enable reductant distribution via the Leidenfrost effect such that these spanning portions of the manifold plate 1214 assist the impingement structures 1204 in reducing or substantially preventing formation of deposits in the decomposition reactor 202. FIG. 15 illustrates the inner tube 1200 removed from the decomposition reactor 202.In other embodiments, the heaters 1202 may instead be replaced with a single heater 1202. The heaters 1202 may be arranged in one or more spirals, helices (e.g., a double helix, etc.), and other similar shapes. It should be understood that the description of the heaters 1202, the heater 1004, the heater 806, the heaters 706, and any other heater disposed at least partially within or around an inner tube applies equally to some embodiments of the heaters 600, the heaters 400, and other heaters used without the inner tube 700. It should also be understood that the description of the heaters 600, heaters 400, and other heaters used without the inner tube 700 applies equally to some embodiments of the heaters 1202, heater 1004, heater 806, heaters 706, and any other heater disposed at least partially within or around an inner tube.In various embodiments, the decomposition reactor 202 is configured to minimize heat transfer therethrough such that the additional heat generated by the heaters (e.g., heaters 400, heaters 600, heaters 706, heater 806, heater 1004, heaters 1202, etc.) is retained by the decomposition reactor 202, thereby providing the exhaust gas and reductant of the downstream component of the exhaust aftertreatment system 200, such as an SCR catalyst, with the additional heat introduced by the heaters. This additional heat may allow higher efficiencies to be achieved by the exhaust aftertreatment system 200. The decomposition reactor 202 may be configured to minimize heat transfer by wrapping insulation around the decomposition reactor 202 as well as constructing the decomposition reactor 202 using different materials (e.g., materials with lower thermal conductivity coefficients, etc.).FIGS. 16 and 17 illustrate an impingement structure 1600 for use in the decomposition reactor 202. The impingement structure 1600 may be the impingement structure 214, the impingement structure 402, the impingement structure 602, the impingement structure 708, the impingement structure 808, the impingement structure 1006, or the impingement structure 1204 described above. In some embodiments, the impingement structure 1600 is constructed from stainless steel. In one embodiment, the impingement structure 1600 is constructed from SS439 stainless steel. The impingement structure 1600 also includes a plurality of supports 1602 (e.g., spacers, etc.). Each of the supports 1602 is configured to be coupled to a surface or component of the decomposition reactor 202.The impingement structure 1600 also includes a plurality of heaters 1604. The heaters 1604 may serve as the heater 212, the heater 400, the heater 600, the heater 706, the heater 806, the heater 1004, or the heater 1202, respectively, described above. The heaters 1604 are coupled to the impingement structure 1600 such that the heaters 1604 are located between the impingement structure 1600 and the component of the exhaust aftertreatment system 1400 to which the supports 1602 are coupled. In some embodiments, each of the heaters 1604 is a heater band. In one embodiment, each of the heaters 1604 is a 300 W ribbon heater.In some embodiments, the impingement structure 1600 also includes a distribution plate 1606. The manifold plate 1606 extends at least partially between the heaters 1604 and the impingement structure 1600. The manifold plate 1606 absorbs the heat provided by the heaters 1604 and serves to increase uniformity of the heat provided to the impingement structure 1600 by the heaters 1604. For example, the manifold plate 1606 may smooth a discontinuity in the heat provided by adjacent heaters 1604 by spanning across the heaters 1604, absorbing the heat provided by the heaters 1604, and distributing that heat across the entire manifold plate 1606 (e.g., across a portion of the manifold plate 1606 extending between the heaters 1604, etc.). In various embodiments, the manifold plate 1606 is constructed from a material having a higher thermal conductivity than a thermal conductivity of the impingement structure 1600. In some embodiments, the manifold plate 1606 is constructed of copper.IV. Exemplary Exhaust Gas Aftertreatment System Having Heating Device and Ammonia Generator Having Bypass LineFIG. 18 illustrates a cross-sectional view of an example exhaust aftertreatment system 1800. The exhaust aftertreatment system 1800 may serve as the exhaust aftertreatment system 100 and / or exhaust aftertreatment system 200 described above. The exhaust aftertreatment system 1800 includes a decomposition reactor 1802. The decomposition reactor 1802 may serve as the decomposition chamber 108 and / or the decomposition reactor 202 described above. The decomposition reactor 1802 includes a body 1803 having an inlet 1804 (e.g., inlet, inlet, etc.) and an outlet 1806 (e.g., outlet, outlet, etc.). The inlet 1804 is configured to receive exhaust gas from an upstream component of the exhaust aftertreatment system 1800, such as a DPF similar to the DPF 106 described above, or a DOC. The outlet 1806 is configured to provide a mixture of exhaust gas and reductant (e.g., treated exhaust gas, etc.) to a downstream component of the exhaust aftertreatment system 1800, such as a catalyst similar to the SCR catalyst 110 described above.The exhaust aftertreatment system 1800 also includes a dosing module 1808. The dosing module 1808 may function as the dosing module 114 and / or dosing module 208 described above. The dosing module 1808 is configured to receive reductant from a reductant pump, similar to the reductant pump 120 that draws reductant from a reductant supply, similar to the reductant source 118. In some embodiments, the dosing module 1808 also receives air from an air pump, similar to the previously described air pump 128, which receives air from an air supply, similar to the air source 130.The dosing module 1808 includes an injector 1810 (e.g., reductant injector, etc.) coupled to the body 1803. The injection device 1810 may serve as the injection device 210 described above. The injection device 1810 is configured to inject reductant from the dosing module 1808 into the decomposition reactor 1802 such that the exhaust gas within the decomposition reactor 1802 may be treated with the reductant. The amount of reductant dosed into the exhaust gas refers to a threshold amount of combustion byproducts discharged to an atmosphere by the exhaust aftertreatment system 1800. In some applications, the exhaust aftertreatment system 1800 is controlled to dose the exhaust with a target amount of reductant such that a target amount of combustion byproducts less than the threshold amount of combustion byproducts is delivered from the exhaust aftertreatment system 1800.The exhaust aftertreatment system 100 includes an inner tube 1812 (e.g., mixer tube, etc.) positioned therein. The inner tube 1812 may serve as the inner tube 700 and / or inner tube 800 described above. The inner tube 1812 is centered on a central axis that is substantially parallel to a central axis of body 1803. The inner tube 1812 is configured to receive the exhaust gas directly from the inlet 1804 (e.g., via an aperture in a front surface of the inner tube 1812, etc.) and provide the exhaust gas to the outlet 1806. The inner tube 1812 is coupled to the body 1803 via a flange 1814. Flange 1814 may serve as the previously described flange 702 and / or flange 802. The flange 1814 may be integral with the inner tube 1812 and / or the body 1803, and / or may be coupled (e.g., attached, bonded, welded, etc.) to the inner tube 1812 and / or the body 1803.The flange 1814 includes a plurality of flange apertures 1815 (e.g., openings, holes, vents, etc.). Each of the plurality of flange apertures 1815 facilitates the passage of the exhaust gas therethrough such that a portion of the exhaust gas may flow from the inlet 1804 to the outlet 1806 without flowing through the inner tube 1812.Decomposition reactor 1802 also includes a guide 1816 (e.g., shield, cone, etc.). The guide 1816 may serve as the guide 704 and / or guide 804 described above. The guide 1816 is coupled to the inner tube 1812 and positioned about the injector 1810. In some embodiments, the guide 1816 is coupled to the body 1803. In other embodiments, the guide 1816 is coupled to the injection device 1810. The guide 1816 is configured to receive the reductant from the injector 1810 and introduce the reductant into the inner tube 1812. The guide 1816 includes a plurality of guide apertures 1817 (e.g., holes, apertures, etc.) configured to receive the exhaust gas such that the received exhaust gas is used to drive the reductant from the injector 1810 into the inner tube 1812. The guide apertures 1817 may be disposed on an upstream surface of the guide 1816, for example.As shown by the flow arrows in FIG. 19, the exhaust gas either flows directly into the inner tube 1812 (e.g., through an inlet of the inner tube 1812, etc.) or via the guide 1816 (e.g., through apertures in the guide 1816, then from the guide 1816 into the inner tube 1812, etc.), or the exhaust gas does not flow into the inner tube 1812 (e.g., the exhaust gas does not flow into the inlet of the inner tube 1812, the exhaust gas does not flow into the guide 1816 via apertures disposed thereon, etc.), and instead flows through the flange apertures 1815 at the flange 1814. The inner tube 1812, flange 1814, flange apertures 1815, and / or guide 1816 may be configured to provide a target amount of the exhaust gas to the temperature controlled catalyst 1818. In some embodiments, the flange apertures 1815 may be selectively allowed to vary (e.g., via electrically controlled actuators, via electrically controlled valves, etc.) to provide the target amount of exhaust gas to the temperature controlled catalyst 1818.The decomposition reactor 1802 includes a temperature controlled catalyst 1818 (e.g., hydrolysis catalyst, etc.). The temperature controlled catalyst 1818 is configured to allow hydrolysis of the exhaust gas to generate ammonia using the reducing agent supplied by the injector 1810. The temperature controlled catalyst 1818 is configured such that the exhaust gas within the inner tube 1812 can only exit through the inner tube 1812 (e.g., en route to the outlet 1806, etc.) by first passing through the temperature controlled catalyst 1818.In some embodiments, the temperature controlled catalyst 1818 may be substantially centered within the body 1803 (e.g., when the central axis of the inner tube 1812 substantially coincides with the central axis of the body 1803, etc.). In this way, temperature controlled catalyst 1818 may be coaxially aligned with an SCR catalyst, such as SCR catalyst 110, downstream of decomposition reactor 1802. This coaxial alignment may significantly reduce the mixing length of the exhaust aftertreatment system 1800.The temperature controlled catalyst 1818 includes a heater 1820. The heater 1820 is controlled such that the temperature controlled catalyst 1818 heats above an activation temperature of the temperature controlled catalyst 1818 so that the temperature controlled catalyst 1818 can catalyze the exhaust gas. This activation temperature may be about 200° C., for example. The heat provided by the heater 1820 assists the temperature controlled catalyst 1818 in performing hydrolysis on the exhaust gas and therefore in producing ammonia.The temperature controlled catalyst 1818 may be configured to have a minimum heat capacity so that the temperature controlled catalyst 1818 may be rapidly heated by the heater 1820. In some applications, the temperature controlled catalyst 1818 is comprised of multiple thin plates (e.g., fins, etc.). For example, temperature controlled catalyst 1818 may be constructed from a plurality of relatively thin parallel plates joined together by either end caps or tension members to form a cartridge-like structure. In some applications, the temperature controlled catalyst 1818 is constructed from a single sheet or a plurality of sheets that have been formed in a corrugated fashion and overlapped with another portion of the same sheet or with an adjacent sheet. In some applications, the temperature controlled catalyst 1818 may be constructed from a material having a relatively low heat capacity (e.g., less than 0.4 joules per gram °C, etc.).Heater 1820 may serve as the heaters 400, heaters 600, heaters 706, and / or heater 806 described above. The heater 1820 is also configured to be heated such that a surface of the temperature controlled catalyst 1818 or a surface of the heater 1820 has a temperature that is higher than an activation temperature (e.g., 200° C. or more, etc.) of the temperature controlled catalyst 1818. In this way, the temperature controlled catalyst 1818 may be utilized to catalyze the exhaust gas without accumulating reductant deposits that would otherwise ultimately result in a decomposition chamber being undesirable.An advantage of incorporating the temperature controlled catalyst 1818 into the decomposition reactor 1802 is that the heat released by the heater 1820 to perform the hydrolysis is provided via the exhaust gas to directly downstream components of the exhaust aftertreatment system 1800, such as an SCR catalyst, thereby potentially increasing the conversion efficiency (e.g., ability to convert the exhaust gas to harmless byproducts, etc.) of these downstream components. This advantage is achieved by positioning the temperature controlled catalyst 1818 within the inner tube 1812 and not convoluted (e.g., curved, non-direct, long, curved, etc.) This is because piping is used to discharge the exhaust gas from the temperature controlled catalyst 1818 back into the decomposition reactor 1802. By avoiding the use of a convoluted duct, the exhaust aftertreatment system 1800 avoids heat losses to the exhaust gas from the temperature controlled catalyst 1818 that would occur (e.g., due to the additional surface area of the duct, etc.) if a convoluted duct were utilized in the exhaust aftertreatment system 1800, thereby providing additional heat to downstream components of the exhaust aftertreatment system 1800. Additionally, the exhaust aftertreatment system 100 avoids additional cost and complexity by not utilizing such convoluted tubing. Additionally, the exhaust aftertreatment system 1800 is capable of having a smaller physical size because such convoluted tubing is not utilized. Still further, by avoiding the use of a convoluted tubing, the flow of exhaust gas from the temperature controlled catalyst 1818 remains substantially straight, thereby increasing the flow rate of exhaust gas through the decomposition reactor 1802 and correspondingly increasing the efficiency of the exhaust aftertreatment system 1800.In various embodiments, the heater 1820 is an electric heater (e.g., resistive heater, heater, etc.) and not a burner (e.g., combustion heater, etc.). As a result, the heater 1820 itself does not have direct discharges (e.g., combustion byproducts, etc.) into the exhaust gas.In some embodiments, the temperature controlled catalyst 1818 is a titanium dioxide catalyst (e.g., TiO 2- catalyst, etc.). In such embodiments, the temperature controlled catalyst 1818 may be formed by sputter deposition of titanium dioxide, by physical vapor deposition of titanium dioxide, by plasma deposition of titanium dioxide, or another similar process. When the temperature controlled catalyst 1818 is a titanium dioxide catalyst, the heater 1820 may heat the temperature controlled catalyst 1818 to a temperature of between 220° C. and 375° C., inclusive. At such temperatures, temperature controlled catalyst 1818 may achieve a decomposition rate that is between 20% and 40%, inclusive, higher than the decomposition rate achieved in other catalysts used in conventional exhaust aftertreatment systems. However, temperature-controlled catalyst 1818 may have other similar formulations, or heater 1820 may heat temperature-controlled catalyst 1818 to other temperatures, such as temperatures less than or equal to 200° C., such that exhaust aftertreatment system 1800 is tailored for a target application.The guide apertures 1817 may be configured to receive a target amount of exhaust gas through the guide 1816, where the target amount is a minimum amount of exhaust gas necessary to drive the reductant from the injector 1810 into the inner tube 1812. By using only the minimum amount of exhaust gas to drive the reductant into the inner tube 1812, only a minimum amount of heating by the heater 1820 is necessary, thereby reducing power consumption of the heater 1820 and making the exhaust aftertreatment system 1800 more efficient.The heater 1820 is connected via leads (e.g., electrical leads, etc.) to a power source (e.g., an internal combustion engine electrical system in communication with the exhaust aftertreatment system 1800, etc.). The leads are routed from outside the body 1803, into the body 1803, and to the heater 1820. In some embodiments, the conduits are routed through the body 1803 to a location proximate the guide 1816, along a downstream surface of the guide 1816, across an upper surface of the inner tube 1812, into the inner tube 1812 at a location proximate the heater 1820, and through the temperature controlled catalyst 1818 to the heater 1820. Such an arrangement can minimize exposure of the conduits to the exhaust gas. In other embodiments, the conduits are routed through the body 1803 at a location near the heater 1820, into the inner tube 1812 at a location near the heater 1820, and through the temperature controlled catalyst 1818 to the heater 1820.In various embodiments, the decomposition reactor 1802 includes a vortex mixer 1822 (e.g., mixing plate, blade mixer, co-vortex mixer, counter-vortex mixer, etc.) coupled to the body 1803. The vortex mixer 1822 is positioned downstream of the flange 1814 and the temperature controlled catalyst 1818 and upstream of the outlet 1806. The vortex mixer 1822 is configured to allow mixing between the exhaust gas provided by the temperature controlled catalyst 1818 and the exhaust gas provided by the flange apertures 1815. The vortex mixer 1822 may be configured such that the decomposition reactor 1802 has a target back pressure and a target mixing length such that the decomposition reactor 1802 is customized for a target application. In other embodiments, decomposition reactor 1802 does not include vortex mixer 1822.V. Exemplary Heater Control SystemFIG. 20 illustrates an example exhaust aftertreatment system 2000. The exhaust aftertreatment system 2000 may be the exhaust aftertreatment system 200 or exhaust aftertreatment system 100 described above. The exhaust aftertreatment system 2000 includes a decomposition reactor 2002. The decomposition reactor 2002 may be the decomposition reactor 202 and / or decomposition reactor 1802 described above. The decomposition reactor 2002 has a body 2003 including an inlet 2004 and an outlet 2006. Inlet 2004 may be inlet 204 or inlet 1804 described above. The outlet 2006 may be the previously described outlet 206 or outlet 1806.The exhaust aftertreatment system 2000 includes a dosing module 2008. The dosing module may be the dosing module 208 or dosing module 1008 described above. The dosing module 2008 includes an injection device 2010. The injection device 2010 may be the injection device 210 or injection device 1010 described above.In some embodiments, decomposition reactor 2002 may include a guide 2012. When the decomposition reactor 2002 includes the guide 2012, the guide 2012 may be the guide 704 or guide 1016 described above. In some embodiments, decomposition reactor 2002 also includes a vortex mixer 2014. When the decomposition reactor 2002 includes the vortex mixer 2014, the vortex mixer 2014 may be the vortex mixer 404, the vortex mixer 404, the vortex mixer 710, the vortex mixer 812, or the vortex mixer 1022.Decomposition reactor 2002 also includes an optionally heated component 2016 coupled to body 2003. The selectively heated component 2016 may be the impingement structure 214, the impingement structures 402, the impingement structures 602, the impingement structures 708, the impingement structure 808, or the temperature controlled catalyst 1018. Decomposition reactor 2002 also includes a heater 2018 coupled to body 2003. The heater 2018 may be the heaters 400, the heaters 600, the heaters 706, the heater 806, or the heater 1020.It should be appreciated that the description of the exhaust aftertreatment system 2000 further describes the exhaust aftertreatment system 200 or the exhaust aftertreatment system 100 in some embodiments. For example, it should be appreciated that the description of the selectively heated component 2016 further describes the impingement structures 602 in some embodiments or further describes the temperature controlled catalyst 1018 in some embodiments.The decomposition reactor 2002 includes a controller 2020. The controller 2020 may include a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., or combinations thereof. The controller 2020 may include memory, which may include, but is not limited to, an electronic, optical, magnetic, or other storage or transmission device capable of providing program instructions to a processor, an ASIC, an FPGA, etc. The memory may include a memory chip, an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a flash memory, or other suitable memory from which the controller 2020 can read instructions. The instructions may include code from any suitable programming language.The controller 2020 is electrically or communicatively coupled to the heater 2018. The controller 2020 is configured to control the heater 2018 such that the selectively heated component 2016 is selectively heated (e.g., if desired, heated, if desired, not heated, etc.). For example, the controller 2020 may be configured to selectively vary an amount of electricity supplied to the selectively heated component 2016. As more electricity is supplied to the selectively heated component 2016, the selectively heated component 2016 may generate more heat. Although not shown, it should be appreciated that the selectively heated component may also include an onboard controller electrically or communicatively coupled to the heater 2018.In some embodiments, decomposition reactor 2002 includes a surface temperature sensor 2022. The surface temperature sensor 2022 is configured to measure a surface temperature of an exterior surface (e.g., an exterior surface, an exposed surface, etc.) of the selectively heated component 2016. For example, the surface temperature sensor 2022 may measure a surface temperature of a surface of the impingement structure 214 or a surface temperature of the temperature controlled catalyst 1018. The surface temperature sensor 2022 is electrically or communicatively coupled to the controller 2020. For example, the controller 2020 may receive a measurement of the surface temperature of the temperature controlled catalyst 1018 from the surface temperature sensor 2022. The measurement of the surface temperature may be provided to the controller 2020 by the surface temperature sensor 2022 in response to the controller 2020 requesting a measurement of the surface temperature of the selectively heated component 2016 by the surface temperature sensor 2022.Decomposition reactor 2002 includes an upstream temperature sensor 2024 coupled to body 2003 and a downstream temperature sensor 2026 coupled to body 2003. The upstream temperature sensor 2024 is positioned between the inlet 2004 and the selectively heated component 2016. The downstream temperature sensor 2026 is positioned between the selectively heated component 2016 and the outlet 2006. The upstream temperature sensor 2024 and the downstream temperature sensor 2026 are electrically or communicatively coupled to the controller 2020. The upstream temperature sensor 2024 is configured to measure a temperature of the exhaust gas upstream of the selectively heated component 2016, and the downstream temperature sensor 2026 is configured to measure a temperature of the exhaust gas downstream of the selectively heated component 2016. The controller 2020 may receive these measurements in response to a request sent by the controller to the upstream temperature sensor 2024 and the downstream temperature sensor 2026. In these embodiments, the controller 2020 also receives a parameter (e.g., mass flow rate of exhaust gas through the exhaust aftertreatment system 2000, etc.) and is configured to associate the parameter, the temperature of the exhaust gas upstream of the selectively heated component 2016, and the temperature of the exhaust gas downstream of the selectively heated component 2016 to determine a surface temperature of the selectively heated component 2016 (e.g., instead of the surface temperature of the selectively heated component 2016 being measured by the surface temperature sensor 2022, etc.). In various embodiments, the upstream temperature sensor 2024 and the downstream temperature sensor 2026 are thermistors (e.g..High temperature thermistors, etc.). In some embodiments, the decomposition reactor 2002 does not include the surface temperature sensor 2022 when the decomposition reactor 2002 includes the upstream temperature sensor 2024 and the downstream temperature sensor 2026.Accordingly, either (i) the surface temperature sensor 2022 is used to directly obtain the surface temperature of the selectively heated component 2016, or (ii) the upstream temperature sensor 2024 and the downstream temperature sensor 2026 are used to indirectly obtain the surface temperature of the selectively heated component 2016. Once the controller 2020 has the surface temperature of the selectively heated component 2016, the controller 2020 implements a heating strategy 2100 to control the heater 2018. The heating strategy 2100 is shown in FIG. 21.The heating strategy 2100 begins at block 2102 with the controller 2020 (e.g., via the surface temperature sensor 2022, the upstream temperature sensor 2024, and the downstream temperature sensor 2026, etc.) obtaining the surface temperature of the selectively heated component 2016. For example, the controller 2020 may determine that the surface temperature of the selectively heated component 2016 is 180° C.The heating strategy 2100 continues at block 2104 with a determination by the controller 2020 as to whether the surface temperature of the selectively heated component 2016 is less than a target surface temperature. The target surface temperature may be downloaded to the controller 2020 (e.g., via a removable storage pen, via the Internet, etc.) or may be determined by the controller 2020 (e.g., via machine learning, etc.). The target surface temperature may be determined based on a plot of the surface temperature of the optionally heated component 2016 as a function of film boiling on the optionally heated component 2016 or a plot of the surface temperature of the optionally heated component 2016 as a function of immediate decomposition on the optionally heated component 2016.If the surface temperature of the selectively heated component 2016 is less than the target surface temperature, the heating strategy 2100 continues at block 2106, where the controller 2020 configures (e.g., instructs, supplies electricity, etc.) the heater 2018 to provide maximum heating to the selectively heated component 2016. The heating strategy 2100 then begins again with block 2102.If the surface temperature of the selectively heated component 2016 is not less than the target surface temperature, the heating strategy 2100 continues at block 2108, wherein the temperature of the exhaust gas within the decomposition reactor 2002 is obtained by the controller 2020. The temperature of the exhaust gas within the decomposition reactor 2002 is determined by the controller 2020 using the upstream temperature sensor 2024 and / or the downstream temperature sensor 2026. For example, the controller 2020 receives a temperature measurement from the upstream temperature sensor 2024 and determines that the temperature of the exhaust gas within the decomposition reactor 2002 is equal to the temperature measurement.The heating strategy 2100 continues at block 2110 with a determination by the controller 2020 as to whether the temperature of the exhaust gas within the decomposition reactor 2002 is greater than or equal to the target surface temperature. If the temperature of the exhaust gas within the decomposition reactor 2002 is greater than or equal to the target surface temperature, the heating strategy 2100 continues at block 2112, where the controller 2020 configures the heater 2018 to provide no heating to the selectively heated component 2016. The heating strategy 2100 then begins again with block 2102.If the temperature of the exhaust gas within the decomposition reactor 2002 is less than the target surface temperature, the heating strategy 2100 continues to determine a power level (e.g., heater duty cycle, etc.) for the heater 2018, at block 2114. The power level for heater 2018 is equal to the sum of the power loss to the exhaust gas and the power loss to the reductant cooling. In various embodiments, the power level for heater 2018 is determined using conditions (e.g., temperature, flow rate, pressure, etc.) of the exhaust gas, a reductant dosing rate requirement, the surface temperature, and surface characteristics. The power level for heater 2018 should be determined while accounting for heat transfer that occurs under film boiling conditions near selectively heated component 2016. The heating strategy 2100 then continues at block 2116 with configuring the heater 2018 to provide heat produced by the power level to the selectively heated component 2016. The heating strategy 2100 then begins again with block 2102.If the injector 2010 meters the exhaust gas before the surface temperature temperature is equal to the target temperature, the controller 2020 may be configured to configure the heater to further heat the selectively heated component 2016 after the surface temperature temperature is equal to the target temperature to decompose deposits that may have formed on the selectively heated component 2016.VII Construction of Exemplary EmbodimentsAlthough this document contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular implementations. 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. Additionally, although 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.As used herein, the terms "substantially," "generally," and similar terms are intended to have a broad meaning consistent with the common and accepted use of those skilled in the art to which the subject matter of this disclosure pertains. It will be apparent to those skilled in the art having the benefit of this disclosure that these terms are intended to allow a description of certain features described and claimed without limiting the scope of these features to the exact numerical ranges provided. Accordingly, these terms are to be construed to indicate that insubstantial or insubstantial modifications or alterations to the described and claimed subject matter are to be considered within the scope of the invention as recited in the appended claims.The terms "coupled," "attached," "attached," "fixed," and the like, as used herein, mean connecting two components directly or indirectly to one another. This connection can be stationary (e.g. permanent) or movable (e.g. removable or releasable). Such joining may be achieved by integrally forming the two components or the two components and all additional intermediate components together as a unitary body, the two components or the two components and any additional intermediate components being secured together.The terms "fluidly coupled," "fluidly connected to," and the like, as used herein, mean that the two components or objects have a path formed between the two components or objects in which a fluid, such as air, liquid reductant, gaseous reductant, aqueous reductant, gaseous ammonia, etc., can flow, either with or without intervening components or articles. Examples of fluid couplings or configurations for enabling fluid communication may include tubes, channels, or any other suitable components for enabling a fluid to flow from one component to another.It is important to note that the structure and arrangement of the system shown in the various exemplary implementations are merely illustrative and not restrictive. It is desired that all changes and modifications that fall within the spirit and / or scope of the described implementations be protected. It should be understood that some features are not mandatory, and that implementations lacking the various features may be considered to be within the scope of the application, the scope being defined by the following claims. When the phrase "a portion" is used, the element may comprise a portion / portion and / or the entire element, unless specifically stated otherwise.Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) such that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Connecting language such as the phrase "at least one of X, Y, and Z," unless specifically stated otherwise, is also to be understood in the context of being used to convey that an object, term, etc. may be either X; Y; Z; X and Y; X and Z; Y and Z; or X, Y and Z (i.e., any combination of X, Y and Z). Therefore, this connecting language generally does not intend to interpret that certain embodiments require at least one of X, at least one of Y, and at least one of Z, unless otherwise indicated.

Claims

An exhaust aftertreatment system (100, 200, 1800, 2000) comprising: a decomposition reactor (202, 1802, 2002) comprising: a body (203, 1803, 2003) through which exhaust gas may flow, the body comprising: an inlet (204, 1804, 2004) configured to receive the exhaust gas at a first temperature and an outlet (206, 1806, 2006) configured to expel the exhaust gas at a second temperature higher than the first temperature, an impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) disposed within the body between the inlet and the outlet, the impingement structure extending into the body and being disposed such that the exhaust gas flowing through the body impinges on the impingement structure, a heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) coupled to the impingement structure and configured to selectively heat the impingement structure, and a guide (704, 804, 1816, 2012) coupled to the body (203, 1803, 2003) downstream of the inlet (204, 1804, 2004), the guide comprising a plurality of guide apertures (705, 805, 1817) configured to receive the exhaust gas from the inlet; an injector (210, 500, 1810, 2010) configured to inject reductant into the body; and a processor programmed to control the heater to heat the impingement structure to a third temperature that is higher than a Leidenfrost temperature of the reductant.The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 1, wherein: the decomposition reactor (202, 1802, 2002) comprises a splash plate, a swirl plate, or a mixing device; and the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) comprises a surface of the splash plate, the swirl plate, or the mixing device.The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 1 or 2, wherein the injection device (210, 500, 1810, 2010) is located upstream of the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600).The exhaust aftertreatment system (100, 200, 1800, 2000) of any of claims 1 to 3, further comprising a vortex mixer (404, 604, 710, 812, 1822, 2014) coupled to the body (203, 1803, 2003) downstream of the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) and upstream of the outlet (206, 1806, 2006), the vortex mixer configured to swirl the exhaust gas passing therethrough.The exhaust aftertreatment system (100, 200, 1800, 2000) of any of claims 1 to 4, further comprising: a flange (702, 802, 1002, 1814) coupled to the body (203, 1803, 2003) downstream of the guide (704, 804, 1816, 2012); and an inner tube (700, 800, 1000, 1200, 1812) coupled to the flange and the guide, the inner tube configured to separately receive the exhaust gas from the inlet (204, 1804, 2004) and the guide and provide the exhaust gas through the flange and toward the outlet (206, 1806, 2006).The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 5, wherein the flange (702, 802, 1002, 1814) comprises a plurality of flange apertures (1815) configured to receive the exhaust gas from the inlet (204, 1804, 2004) and provide the exhaust gas through the flange and toward the outlet (206, 1806, 2006).The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 5 or 6, wherein the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) is at least partially disposed within the inner tube (700, 800, 1000, 1200, 1812) or the guide (704, 804, 1816, 2012).The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 7, wherein the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) is coupled to at least one of the inner tube (700, 800, 1000, 1200, 1812) or the guide (704, 804, 1816, 2012).An exhaust aftertreatment system (100, 200, 1800, 2000) comprising: a decomposition reactor (202, 1802, 2002) comprising: a body (203, 1803, 2003) through which exhaust gas may flow, the body comprising: an inlet (204, 1804, 2004) configured to receive the exhaust gas and an outlet (206, 1806, 2006) configured to selectively expel the exhaust gas; a guide (704, 804, 1816, 2012) coupled to the body downstream of the inlet, the guide extending into the body and comprising a plurality of guide apertures (705, 805, 1817) configured to receive the exhaust gas from the inlet; a flange (702, 802, 1002, 1814) coupled to the body downstream of the guide; an inner tube (700, 800, 1000, 1200, 1812) coupled to the flange and the guide, the inner tube configured to separately receive the exhaust gas from the inlet and the guide and provide the exhaust gas through the flange and toward the outlet; a temperature controlled catalyst (1018, 1818) disposed within the inner tube downstream of the guide, the temperature controlled catalyst disposed such that the exhaust gas passing through the inner tube toward the outlet impinges upon the temperature controlled catalyst; and a heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) coupled to the temperature controlled catalyst and configured to selectively heat the temperature controlled catalyst; a processor programmed to control the heater to heat the temperature controlled catalyst to perform hydrolysis of the exhaust gas impinging on the temperature controlled catalyst.The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 9, wherein the inner tube (700, 800, 1000, 1200, 1812) and the body (203, 1803, 2003) are coaxial such that the temperature controlled catalyst (1018, 1818) is centered on a central axis of the body.The exhaust aftertreatment system (100, 200, 1800, 2000) of claim 9 or 10, wherein the guide (704, 804, 1816, 2012), the inner tube (700, 800, 1000, 1200, 1812), the flange (702, 802, 1002, 1814), the temperature controlled catalyst, and the heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) are contained within the body (203, 1803, 2003).The exhaust aftertreatment system (100, 200, 1800, 2000) of any of claims 9 to 11, further comprising a vortex mixer (404, 604, 710, 812, 1822, 2014) coupled to the body (203, 1803, 2003) downstream of the inner tube (700, 800, 1000, 1200, 1812) and upstream of the outlet (206, 1806, 2006), the vortex mixer configured to swirl the exhaust gas passing therethrough.A decomposition reactor (202, 1802, 2002) for an exhaust aftertreatment system (100, 200, 1800, 2000), the decomposition reactor comprising: an inlet (204, 1804, 2004) configured to receive an exhaust gas; an outlet (206, 1806, 2006) configured to provide the exhaust gas; a body (203, 1803, 2003) extending between the inlet and the outlet; an inner tube (700, 800, 1000, 1200, 1812) positioned within the body such that at least a portion of the inner tube is separated from the body by an air gap extending about the inner tube, the inner tube comprising an impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) positioned proximate the inlet; a manifold plate (1012, 1214, 1606) coupled to the impingement structure; and a first heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) coupled to the manifold plate; wherein the manifold plate separates the first heater from the impingement structure.The decomposition reactor (202, 1802, 2002) of claim 13, further comprising: a second heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) coupled to the manifold plate (1012, 1214, 1606), wherein the second heater is separated from the first heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) by a gap; wherein the manifold plate separates the second heater from the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600); and wherein the manifold plate extends between the first heater and the second heater.The decomposition reactor (202, 1802, 2002) of claim 13 or 14, further comprising: a plurality of fins (1010), wherein each of the plurality of fins is coupled to the inner tube (700, 800, 1000, 1200, 1812) proximate a downstream end (810, 1008, 1206) of the inner tube; wherein the inner tube further comprises an injector aperture (1011, 1211) located between the downstream end and the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600); and wherein the injector aperture is configured to receive an injector (210, 500, 1810, 2010).The decomposition reactor (202, 1802, 2002) of claim 13 or 14, further comprising: a mixing plate (1209) coupled to the inner tube (700, 800, 1000, 1200, 1812), the mixing plate comprising a mixing plate aperture (1210) configured to allow the exhaust gas to pass through the mixing plate and a mixing plate channel (1212) configured to allow the exhaust gas to pass through the mixing plate, the mixing plate channel configured to cause the exhaust gas exiting the mixing plate channel to swirl downstream of the mixing plate; wherein the inner tube further comprises: an upstream end (1010, 1208); and a downstream end (810, 1008, 1206) opposite the upstream end; and wherein the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) is disposed between the upstream end and the mixing plate.The decomposition reactor (202, 1802, 2002) of claim 16, wherein the inner tube (700, 800, 1000, 1200, 1812) further comprises an injector aperture (1011, 1211) disposed between the upstream end (1010, 1208) and the mixing plate (1209).The decomposition reactor (202, 1802, 2002) of claim 17, wherein the injector aperture (1011, 1211) is aligned with the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600).The decomposition reactor (202, 1802, 2002) of any of claims 16 to 18, wherein the first heater (212, 400, 600, 706, 806, 1004, 1202, 1604, 1820, 2018) is configured to heat the impingement structure (214, 402, 602, 708, 808, 1006, 1204, 1600) to a temperature that is between 120 degrees Celsius and 151 degrees Celsius, inclusive.

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