Mixer for exhaust after treatment system

Abstract

A mixer for an exhaust aftertreatment system that receives exhaust and a treatment fluid. The mixer includes a mixer body centered on a mixer body center axis. The mixer body includes a first portion that couples to a decomposition chamber housing. The mixer body further includes a second portion having a first edge at the first portion and having a first radius, and a second edge opposite the first edge and having a second radius less than the first radius. Each of the first edge and the second edge has an arc angle between 170 degrees and 210 degrees. The mixer body further includes a third portion extending from the second edge of the second portion in a direction at least partially along the mixer body center axis. The mixer further includes a wall coupled to the mixer body. The wall extends radially outward from the second portion.

Description

[0001]Atty. Dkt. No.: 106389-9079 MIXER FOR EXHAUST AFTERTREATMENT SYSTEM CROSS-REFERENCE TO RELATED PATENT APPLICATION This application claims the benefit of and priority to India Provisional Patent Application No. 202441010099, filed February 14, 2024, which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present application relates generally to a mixer for exhaust aftertreatment systems for an internal combustion engine system. BACKGROUND The exhaust of internal combustion engines, such as diesel engines, includes nitrogen oxide (NOX) compounds. It is desirable to reduce NOXemissions to comply with environmental regulations, for example. To reduce NOXemissions, a treatment fluid may be dosed into the exhaust by a doser assembly within an aftertreatment system. The treatment fluid facilitates conversion of a portion of the exhaust into non-NOX emissions, such as nitrogen (N2), carbon dioxide (CO2), and water (H2O), thereby reducing NOXemissions. These aftertreatment systems may include a mixer that facilitates mixing of the treatment fluid and the exhaust. SUMMARY In one embodiment, a mixer for an exhaust aftertreatment system receives exhaust from an exhaust conduit and a treatment fluid from an injector of a dosing module. The mixer includes a mixer body centered on a mixer body center axis. The mixer body includes a first portion that couples to a decomposition chamber housing. The mixer body further includes a second portion having a first edge at the first portion and having a first radius, and a second edge opposite the first edge and having a second radius less than the first radius. Each of the first edge and the second edge has an arc angle between 170 degrees and 210 degrees. The -1- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 mixer body further includes a third portion extending from the second edge of the second portion in a direction at least partially along the mixer body center axis. The mixer further includes a wall coupled to the mixer body. The wall extends radially outward from the second portion. In some embodiments, the wall includes an edge parallel to the mixer body center axis. In some embodiments, the wall extends radially outward from the second portion to the decomposition chamber housing. In some embodiments, the first portion is disposed along a plane that is orthogonal to the mixer body center axis. In some embodiments, the second portion does not include apertures. In some embodiments, the first portion has a flat surface, the second portion has a first partial frustoconical shape, and the third portion has a cylindrical shape or a second partial frustoconical shape. In some embodiments, the second portion extends from the first portion at a first angle relative to the first portion between 100 degrees and 130 degrees, inclusive. The third portion extends from the second portion at a second angle relative to the mixer body center axis between 150 degrees and 270 degrees, inclusive. In some embodiments, a mixing assembly for an exhaust aftertreatment system includes a decomposition chamber housing. The mixer is coupled to the decomposition chamber housing via the first portion. In some embodiments, the decomposition chamber housing and the mixer are coaxial. In some embodiments, ^^^ ൌ 2^^^, 0.45^^^ ^ ^^ଶ ^ 0.6^^^, and 0.05^^ଶ ^ ^^^ ^0.2^^ଶ, where ^^^is a distance from the mixer body center axis to an outer edge of the first -2- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 portion, ^^^is a first reference diameter, ^^ଶis a second reference diameter, and ^^^is a length of the first portion. In some embodiments, ^^^ ൌ 2^^^, 0.45^^^ ^ ^^ଶ ^ 0.6^^^, and 0.6^^ଶ ^ ^^ଶ ^0.85^^ଶ, where ^^^is a distance from the mixer center axis to an outer of the first portion, ^^^is a first reference length of the second portion. In some embodiments, ^^^ ൌ 2^^^, 0.45^^^ ^ ^^ଶ ^ 0.6^^^, and 0.05^^ଶ ^ ^^ଷ ^0.2^^ଶ, where ^^^is a distance from the mixer body center axis to an outer edge of the first portion, ^^^is a first reference diameter, ^^ଶis a second reference diameter, and ^^ଷis a length of the third portion. In some embodiments, the first portion extends radially outward from the first edge of the second portion. In some embodiments, the wall extends radially outward from both the second portion and the third portion. In another embodiment, an exhaust aftertreatment system includes a decomposition chamber housing that receives exhaust from an internal combustion engine. The exhaust aftertreatment system further includes a dosing module that includes an injector that injects a treatment fluid into the decomposition chamber housing. The exhaust aftertreatment system further includes a heater disposed at least partially within the decomposition chamber housing. The exhaust aftertreatment system further includes a mixer disposed upstream of the heater and that receives the exhaust and the treatment fluid. The mixer includes a mixer body centered on a mixer body center axis. The mixer body includes a first portion coupled to the decomposition chamber housing and a second portion. The second portion has a first edge at the first portion and having a first radius and a second edge opposite the first edge and having a second radius less than the first radius. Each of the first edge and the second edge have an arc angle less than 360 degrees. The mixer further includes a wall coupled to the mixer body. The wall extends radially outward from the second portion. -3- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 In some embodiments, the mixer is disposed directly upstream of the heater. In some embodiments, the mixer body further includes a third portion extending from the second edge of the second portion in a direction at least partially along the mixer body center axis. In some embodiments, the mixer is directly in contact with the heater. In some embodiments, the second portion extends from the first portion in a direction axially away from the heater. In some embodiments, the exhaust aftertreatment further includes a sensor that provides a signal associated with at least one of the exhaust or the treatment fluid. The exhaust aftertreatment system further includes a controller communicatively coupled to the sensor and the heater. The controller receives the signal from the sensor, determines a temperature of the at least one of the exhaust or the treatment fluid based on the signal, and, in response to determining that the temperature of the at least one of the exhaust or the treatment fluid is below a target fluid temperature, increases an operating temperature of the heater. BRIEF DESCRIPTION OF THE DRAWINGS The 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 description, the drawings, and the claims, in which: FIG. 1 is a block schematic diagram of an example exhaust aftertreatment system; FIG. 2 is a front view of a portion of another example exhaust aftertreatment system; FIG. 3 is a side view of the portion of the exhaust aftertreatment system of FIG. 2; FIG. 4 is a cross-sectional view of the portion of the exhaust aftertreatment system of FIG. 2 taken along plane 4-4 in FIG. 2; -4- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 FIG. 5 is a cross-sectional view of the portion of the exhaust aftertreatment system of FIG. 2 taken along plane 5-5 in FIG. 3; FIG. 6 is a cross-sectional view of a portion of another example exhaust aftertreatment system; FIG. 7 is a view of Detail A in FIG. 6; FIG. 8 is a perspective view of the portion of the exhaust aftertreatment system of FIG. 7; FIG. 9 is a perspective view of a portion of yet another example exhaust aftertreatment system; FIG. 10 is a perspective view of a portion of yet another example exhaust aftertreatment system; FIG. 11 is a perspective view of a portion of yet another example exhaust aftertreatment system; FIG. 12 is a cross-sectional view of an example mixer; and FIG. 13 is a front view of yet another example mixer. It will be recognized that the Figures are schematic representations for purposes of illustration. The Figures are provided for the purpose of illustrating one or more implementations with the explicit understanding that the Figures will not be used to limit the scope or the meaning of the claims. DETAILED DESCRIPTION Following below are more detailed descriptions of various concepts related to, and implementations of, methods, apparatuses, and systems for providing a mixer for an exhaust aftertreatment system. The various concepts introduced above and discussed in greater detail below may be implemented in any of a number of ways, as the described concepts are not -5- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes. I. Overview Internal combustion engines (e.g., diesel internal combustion engines, etc.) produce exhaust that is often treated by a doser assembly within an exhaust aftertreatment system. The doser assembly typically treats the exhaust using a treatment fluid (e.g., reductant, hydrocarbon fluid, etc.) released from the doser assembly by an injector of a doser. The treatment fluid, such as reductant, may be adsorbed by a catalyst member. The adsorbed treatment fluid in the catalyst member may function to reduce NOX in the exhaust. The treatment fluid, such as hydrocarbon fluid, may increase a temperature of the exhaust to reduce NOXin the exhaust. The doser assembly is mounted on a component of the exhaust aftertreatment system. For example, the doser assembly may be mounted to a decomposition reactor, an exhaust conduit, a panel, or other similar components of the exhaust aftertreatment system. Mixing the exhaust with the treatment fluid may improve the reduction of NOXin the exhaust or improve heating of the exhaust. A device can be used to facilitate mixing between the exhaust and the treatment fluid through turbulent flow (e.g., turbulence, etc.). Turbulence in the form of swirling (e.g., eddies, etc.) improves the mixing characteristics of a fluid. For example, swirling of the exhaust causes dispersal of treatment fluid within the exhaust, thereby improving the mixing between the exhaust and the treatment fluid. However, a device in a flow path of the treatment fluid may be prone to collecting (e.g., accumulating, etc.) deposits of the treatment fluid. These deposits may reduce a mixing efficiency of the device and a flow rate of the exhaust and / or the treatment fluid within a conduit that the device is within or fluidly coupled to. Implementations described herein relate to a mixer that includes a mixer body and a wall extending radially outward from a portion of the mixer body. The mixer body and the wall are structured to alter the flow of the exhaust and / or the treatment fluid so that the mixer body and the wall cumulatively cause the exhaust to obtain a target flow distribution and / or the treatment fluid to obtain a target uniformity index downstream of the mixer. It may be desirable -6- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 to obtain a uniform flow distribution and treatment fluid uniformity index at an inlet of an catalyst member to obtain a relatively high NOX conversion efficiency. The mixer body includes a first portion configured to couple to a decomposition chamber housing and a second portion that has a first edge at the first portion and a second edge opposite the first edge. Each of the first edge and the second edge has an arc angle less than 360 degrees, such that the second portion does not radially restrict an entirety of the decomposition chamber housing, thereby providing a relatively low pressure drop (e.g., the pressure of the fluid at the inlet of the decomposition chamber housing less the pressure of the fluid at the outlet of the decomposition chamber housing, etc.) in a relatively compact space. The mixer may minimize spray impingement on surfaces due to swirl flow and relatively high shear stresses produced by the mixer, thereby mitigating deposit formation and accumulation within the mixer and associated components of the exhaust aftertreatment system. II. Overview of Example Exhaust Aftertreatment System FIGS. 1-8 depict an exhaust aftertreatment system 100 configured to treat an exhaust released by an internal combustion engine of an internal combustion engine system. The exhaust aftertreatment system 100 includes an exhaust conduit system 104 configured to receive the exhaust from the internal combustion engine. The exhaust aftertreatment system 100 further includes a particulate filter 106 (e.g., a diesel particulate filter (DPF), etc.) coupled to the exhaust conduit system 104 and configured to (e.g., structured to, able to, etc.) remove particulate matter, such as soot, from the exhaust flowing in the exhaust conduit system 104. The particulate filter 106 includes an inlet, where the exhaust is received, and an outlet, where the exhaust exits after having particulate matter substantially filtered from the exhaust and / or converting the particulate matter into carbon dioxide. In some implementations, the particulate filter 106 may be omitted. The exhaust aftertreatment system 100 further includes a decomposition chamber housing 108 (e.g., reactor, reactor pipe, conduit, housing, etc.) disposed downstream of the particulate filter 106. The decomposition chamber housing 108 is configured to receive the exhaust from the particulate filter 106. The exhaust aftertreatment system 100 further includes a -7- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 treatment fluid delivery system 102 coupled to the decomposition chamber housing 108. The treatment fluid delivery system 102 is configured to deliver treatment fluid to the decomposition chamber housing 108. The treatment fluid may be, for example, a reductant (e.g., urea, diesel exhaust fluid (DEF), Adblue®, a urea water solution (UWS), an aqueous urea solution (e.g., AUS32, etc.), and / or other similar fluids) or a hydrocarbon fluid (e.g., fuel, oil, additive, etc.). When the reductant is introduced into the exhaust, reduction of emission of undesirable components (e.g., NOX, etc.) in the exhaust may be facilitated. When the hydrocarbon fluid is introduced into the exhaust, the temperature of the exhaust may be increased (e.g., to facilitate regeneration of components of the exhaust aftertreatment system 100, etc.). For example, the exhaust aftertreatment system 100 may include a spark plug 109 (e.g., igniter, etc.) configured to increase the temperature of the exhaust by combusting the hydrocarbon fluid within the exhaust. The decomposition chamber housing 108 includes an inlet in fluid communication with the particulate filter 106 to receive the exhaust containing NOXemissions and an outlet for the exhaust, NOXemissions, ammonia, and / or the treatment fluid to flow to downstream components of the exhaust aftertreatment system 100. The treatment fluid delivery system 102 includes a doser assembly 112 (e.g., dosing module, etc.) configured to dose the treatment fluid into the decomposition chamber housing 108 (e.g., via an injector). The doser assembly 112 is mounted to the decomposition chamber housing 108 such that the doser assembly 112 may dose the treatment fluid into the exhaust flowing through the exhaust conduit system 104. The doser assembly 112 is fluidly coupled to (e.g., fluidly configured to communicate with, etc.) a treatment fluid source 114. The treatment fluid source 114 may include multiple treatment fluid sources 114. The treatment fluid source 114 may be, for example, a diesel exhaust fluid tank containing Adblue®. A treatment fluid pump 116 (e.g., supply unit, etc.) is used to pressurize the treatment fluid from the treatment fluid source 114 for delivery to the doser assembly 112. In some embodiments, the treatment fluid pump 116 is pressure-controlled (e.g., controlled to obtain a target pressure, etc.). The treatment fluid pump 116 may include a treatment fluid filter 118. The treatment fluid filter 118 filters (e.g., strains, etc.) the treatment fluid prior to the treatment fluid being provided to internal components (e.g., -8- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 pistons, vanes, etc.) of the treatment fluid pump 116. For example, the treatment fluid filter 118 may inhibit or prevent the transmission of solids (e.g., solidified treatment fluid, contaminants, etc.) to the internal components of the treatment fluid pump 116. In this way, the treatment fluid filter 118 may facilitate prolonged desirable operation of the treatment fluid pump 116. In some embodiments, the treatment fluid pump 116 is coupled (e.g., fastened, attached, affixed, welded, etc.) to a chassis of a vehicle associated with the exhaust aftertreatment system 100. The doser assembly 112 includes at least one injector 120. Each injector 120 is configured to dose the treatment fluid into the exhaust (e.g., within the decomposition chamber housing 108, etc.) at an injection axis 119. The exhaust aftertreatment system 100 may include a mixer 121 (e.g., a mixing body assembly, a swirl generating device, a vane plate, inlet plate, deflector plate, etc.). In some embodiments, at least a portion of the mixer 121 may be located within the decomposition chamber housing 108. In further embodiments, at least a portion of the mixer 121 may also be located in a conduit of the exhaust conduit system 104 (e.g., a conduit upstream of the decomposition chamber housing 108, etc.). The mixer 121 is configured to receive exhaust from the decomposition chamber housing 108 and the treatment fluid from the injector 120. The mixer 121 is also configured to facilitate mixing of the exhaust and the treatment fluid. The mixer 121 is configured to facilitate swirling (e.g., tumbling, rotation, etc.) of the exhaust and / or the treatment fluid and mixing (e.g., combination, etc.) of the exhaust and the treatment fluid so as to disperse the treatment fluid within the exhaust downstream of the mixer 121. By dispersing the treatment fluid within the exhaust (e.g., to obtain an increased uniformity index, etc.) using the mixer 121, reduction of emission of undesirable components in the exhaust is enhanced. In some embodiments, the injection axis 119 extends into the mixer 121. The injection axis 119 may extend into the mixer 121 at an angle relative to a central axis of the mixer 121. For example, in some embodiments, the injection axis 119 may be substantially coincident with a central axis of the mixer 121. In other embodiments, the injection axis 119 may be substantially perpendicular to the central axis of the mixer 121. In yet other embodiment, the injection axis 119 may be substantially parallel to the central axis of the mixer 121. -9- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 In some embodiments, the injector 120 is not directly coupled to the mixer 121. In these embodiments, the injector 120 and the mixer 121 may each be coupled to a same component (e.g., housing, panel, chamber, body, etc.). In other embodiments, the injector 120 is directly coupled to the mixer 121. In these embodiments, the injector 120 and the mixer 121 may also each be coupled to the same component. In some embodiments, the injector 120 is not disposed within the mixer 121. In other embodiments, the injector 120 may be at least partially disposed within the mixer 121. In some embodiments, the treatment fluid delivery system 102 also includes an air pump 122. In these embodiments, the air pump 122 draws air from an air source 124 (e.g., air intake, etc.) and through an air filter 126 disposed upstream of the air pump 122. Additionally, the air pump 122 provides the air to the doser assembly 112 via a conduit. In these embodiments, the doser assembly 112 is configured to mix the air and the treatment fluid into an air-treatment fluid mixture and to provide the air-treatment fluid mixture into the decomposition chamber housing 108. In other embodiments, the treatment fluid delivery system 102 does not include the air pump 122, the air source 124, and / or the air filter 126. In such embodiments, the doser assembly 112 is not configured to mix the treatment fluid with the air. The spark plug 109, the doser assembly 112, and the treatment fluid pump 116 are also electrically or communicatively coupled to a treatment fluid delivery system controller 128. The treatment fluid delivery system controller 128 may control the spark plug 109 to ignite the treatment fluid in the decomposition chamber housing 108. The treatment fluid delivery system controller 128 controls the doser assembly 112 to dose the treatment fluid into the decomposition chamber housing 108. The treatment fluid delivery system controller 128 may also control the treatment fluid pump 116. The treatment fluid delivery system controller 128 includes a processing circuit 130. The processing circuit 130 includes a processor 132 and a memory 134. The processor 132 may include a microprocessor, an application-specific integrated circuit (ASIC), a field- programmable gate array (FPGA), etc., or combinations thereof. The memory 134 may include, -10- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 but is not limited to, electronic, optical, magnetic, or any other storage or transmission device capable of providing a processor, ASIC, FPGA, etc. with program instructions. This memory 134 may include a memory chip, Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), flash memory, or any other suitable memory from which the treatment fluid delivery system controller 128 can read instructions. The instructions may include code from any suitable programming language. The memory 134 may include various modules that include instructions which are configured to be implemented by the processor 132. In various embodiments, the treatment fluid delivery system controller 128 is configured to communicate with a central controller 136 (e.g., engine control unit (ECU), engine control module (ECM), etc.) of an internal combustion engine having the exhaust aftertreatment system 100. In some embodiments, the central controller 136 and the treatment fluid delivery system controller 128 are integrated into a single controller. In some embodiments, the central controller 136 is communicable with a display device (e.g., screen, monitor, touch screen, heads up display (HUD), indicator light, etc.). The display device may be configured to change state in response to receiving information from the central controller 136. For example, the display device may be configured to change between a static state (e.g., displaying a green light, displaying a “SYSTEM OK” message, etc.) and an alarm state (e.g., displaying a blinking red light, displaying a “SERVICE NEEDED” message, etc.) based on a communication from the central controller 136. By changing state, the display device may provide an indication to a user (e.g., operator, etc.) of a status (e.g., operation, in need of service, etc.) of the treatment fluid delivery system 102. The exhaust aftertreatment system 100 further includes a catalyst member 138 (e.g., SCR (Selective Catalytic Reduction) catalyst member, etc.) disposed downstream of the decomposition chamber housing 108. As a result, the treatment fluid is injected upstream of the catalyst member 138 such that the catalyst member 138 receives a mixture of the treatment fluid and exhaust. The treatment fluid droplets undergo the processes of evaporation, -11- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 thermolysis, and hydrolysis to form non-NOXemissions (e.g., gaseous ammonia, etc.) within the exhaust conduit system 104. The catalyst member 138 includes an inlet in fluid communication with the decomposition chamber housing 108 from which exhaust and treatment fluid are received and an outlet in fluid communication with an outlet 140 of the exhaust conduit system 104. The outlet 140 may release the treated exhaust into an ambient environment or another treatment system. The exhaust aftertreatment system 100 may further include an oxidation catalyst member (e.g., a diesel oxidation catalyst (DOC), ammonia oxidation catalyst (AMOX), etc.) in fluid communication with the exhaust conduit system 104 (e.g., downstream of the catalyst member 138, upstream of the particulate filter 106, upstream of the decomposition chamber housing 108, etc.) to oxidize hydrocarbons and carbon monoxide in the exhaust. In some implementations, the particulate filter 106 may be positioned downstream of the decomposition chamber housing 108. For instance, the particulate filter 106 and the catalyst member 138 may be combined into a single unit. In some implementations, the doser assembly 112 may instead be positioned downstream of a turbocharger or upstream of the turbocharger. The exhaust aftertreatment system 100 may further include a doser mounting bracket 142 (e.g., mounting bracket, coupler, plate, etc.). The doser mounting bracket 142 couples the doser assembly 112 to a component of the exhaust aftertreatment system 100 (e.g., the decomposition chamber housing 108, etc.). The doser mounting bracket 142 may be configured as an insulator (e.g., vibrational insulator, thermal insulator, etc.). For example, the doser mounting bracket 142 may be configured to mitigate the transfer of heat from the exhaust passing through the exhaust conduit system 104 to the doser assembly 112. In this way, the doser assembly 112 is capable of operating more efficiently and desirably. The doser mounting bracket 142 may be configured to mitigate transfer of vibrations from the component of the exhaust aftertreatment system 100 to the doser assembly 112. Additionally, the doser mounting bracket 142 is configured to aid in reliable installation of the doser assembly 112. This may -12- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 decrease manufacturing costs associated with the exhaust aftertreatment system 100 and ensure repeated desirable installation of the doser assembly 112. In various embodiments, the doser mounting bracket 142 couples the doser assembly 112 to the decomposition chamber housing 108. In some embodiments, the doser mounting bracket 142 couples the doser assembly 112 to an exhaust conduit of the exhaust conduit system 104. For example, the doser mounting bracket 142 may couple the doser assembly 112 to an exhaust conduit of the exhaust conduit system 104 that is upstream of the decomposition chamber housing 108. In some embodiments, the doser mounting bracket 142 couples the doser assembly 112 to the particulate filter 106 and / or the catalyst member 138. The location of the doser mounting bracket 142 may be varied depending on the application of the exhaust aftertreatment system 100. For example, in some exhaust aftertreatment systems 100, the doser mounting bracket 142 may be located further upstream than in other exhaust aftertreatment systems 100. Furthermore, some exhaust aftertreatment systems 100 may include multiple doser assemblies 112 and therefore may include multiple doser mounting brackets 142. FIGS. 2-4 illustrate embodiments of the exhaust aftertreatment system 100, where a flow direction of the exhaust is shown by dashed lines. In these embodiments, the decomposition chamber housing 108 houses the mixer 121. The exhaust conduit system 104 includes an exhaust conduit inlet 144 fluidly coupled to the internal combustion engine and is configured to receive the exhaust from the internal combustion engine and provide the exhaust to components of the exhaust aftertreatment system 100 (e.g., the decomposition chamber housing 108, the catalyst member 138, etc.). The exhaust aftertreatment system 100 further includes a heater 146 (e.g., grid gas heater, surface heater, resistance heater, electrical heater, etc.) disposed downstream of the exhaust conduit inlet 144 and upstream of the catalyst member 138. The heater 146 may be disposed at least partially within the decomposition chamber housing 108. The heater 146 is configured to increase temperatures of the exhaust and / or the treatment fluid, which may allow the catalyst member 138 to transition from the ambient temperature to the operating -13- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 temperature quickly. Increasing the temperature of the exhaust may improve mixing between the exhaust and the treatment fluid and mitigate deposit accumulation in the exhaust conduit system 104. The heater 146 includes heater wires 148. The heater 146 is electrically or communicatively coupled to the treatment fluid delivery system controller 128 via the heater wires 148. The treatment fluid delivery system controller 128 may be configured to cause the heater 146 to operate at a target heater temperature. The exhaust aftertreatment system 100 may include one or more sensors 150. In some embodiments, the sensors 150 include a first sensor disposed downstream of the exhaust conduit inlet 144 and upstream of the heater 146 and a second sensor disposed downstream of the catalyst member 138 and upstream of the outlet 140. The sensors 150 are electrically or communicatively coupled to the treatment fluid delivery system controller 128 and are configured to provide signals associated with the exhaust and / or the treatment fluid to the treatment fluid delivery system controller 128. The treatment fluid delivery system controller 128 is configured to receive the signals from the sensors 150. In some embodiments, at least one of the sensors 150 is a temperature sensor that transmits a signal to the treatment fluid delivery system controller 128, where the treatment fluid delivery system controller 128 is configured to determine a temperature of the exhaust and / or the treatment fluid based on the signal. In some further embodiments, the treatment fluid delivery system controller 128 may determine the target heater temperature at which the heater 146 operates based on the temperatures determined based on the signal from the temperature sensor (e.g., sensor 150). For example, in response to the treatment fluid delivery system controller 128 determining that the temperature of the exhaust and / or the treatment fluid upstream and / or downstream of the heater 146 is below a target fluid temperature, the treatment fluid delivery system controller 128 increases the target heater temperature of the heater 146. In some embodiments, at least one of the sensors 150 is a pressure sensor that transmits a signal to the treatment fluid delivery system controller 128, where the treatment fluid delivery system controller 128 is configured to determine a pressure of the exhaust and / or -14- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 the treatment fluid based on the signal. In some embodiments, at least one of the sensors 150 is a uniformity index (UI) sensor that transmits a signal to the treatment fluid delivery system controller 128, such that the treatment fluid delivery system controller 128 is configured to determine a UI of the exhaust and the treatment fluid based on the signal. The UI, a numerical value between zero and one, may be interpreted as a mixing measurement, where a fully mixed mixture (e.g., exhaust and treatment fluid mixture) produces a value of one and a non-fully mixed mixture produces a value less than one. The exhaust aftertreatment system 100 may include an inlet conduit 152 coupled directly to the decomposition chamber housing 108 and configured to provide the exhaust and the treatment fluid to the decomposition chamber housing 108. As illustrated in FIG. 4, the inlet conduit 152 is centered around an inlet conduit center axis 154. The decomposition chamber housing 108 may be centered around a decomposition chamber housing center axis 156. As illustrated in FIGS. 4, 7, 8 and 12, the decomposition chamber housing 108 may include an inlet aperture 155 configured to receive the inlet conduit 152. The inlet aperture 155 may be centered around an inlet aperture center axis 157. The inlet aperture 155 may have an elliptical shape, a square shape, a rectangular shape, a triangular shape, a trapezoidal shape, a circular shape, a semi-circular shape, or the like. In some embodiments, as illustrated in FIG. 4, the inlet conduit 152 is coupled to the decomposition chamber housing 108 along a tangential direction of the decomposition chamber housing 108, such that the fluid (e.g., exhaust, treatment fluid, mixture of exhaust and treatment fluid) flows into the decomposition chamber housing 108 semi-tangentially (i.e., as opposed to axially, as opposed to radially, etc.), thereby enhancing swirling of the fluid by having the fluid travel along a curved inner surface of the decomposition chamber housing 108. Further in these embodiments, the inlet conduit center axis 154 does not intersect the decomposition chamber housing center axis 156. The inlet conduit center axis 154 may be parallel to a tangential reference axis 158 that is tangential to the decomposition chamber housing 108 and parallel to a radial reference axis 160 that extends radially from the decomposition chamber housing center axis 156. The inlet conduit center axis 154, the tangential reference axis 158, and the radial -15- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 reference axis 160 may be coplanar, where the inlet conduit center axis 154 is disposed between the tangential reference axis 158 and the radial reference axis 160. III. Overview of Mixer FIGS. 6-13 illustrate various embodiments of a mixer 200 (e.g., the mixer 121, etc.) configured to facilitate mixing of the exhaust and the treatment fluid. In some embodiments, the exhaust aftertreatment system 100 includes a mixing assembly that includes the decomposition chamber housing 108 and the mixer 200. The mixer 200 may be disposed within the decomposition chamber housing 108. The mixer 200 may be disposed downstream of the exhaust conduit inlet 144 and upstream of the heater 146. As illustrated in FIGS. 9-11, the mixer 200 may be disposed directly upstream of the heater 146. The mixer 200 is further configured to receive the exhaust from a component of the exhaust conduit system 104 (e.g., exhaust conduit inlet 144, the inlet conduit 152, etc.) and the treatment fluid from the injector 120 of the doser assembly 112. In some embodiments, as illustrated in FIGS. 9-11, the mixer 200 is axially spaced from the heater 146. In other embodiments, the mixer 200 is in contact with the heater 146. The mixer 200 includes a mixer body 210 centered on a mixer body center axis 212. In some embodiments, as illustrated in FIGS. 9-13, the mixer body center axis 212 and the decomposition chamber housing center axis 156 are coaxial. In other embodiments, as illustrated in FIGS. 7 and 8, the mixer body center axis 212 and the decomposition chamber housing center axis 156 are not coaxial. In some further embodiments, as illustrated in FIGS. 7 and 8, the mixer body center axis 212 and the decomposition chamber housing center axis 156 are parallel and not coaxial. The mixer body 210 includes a first portion 220 configured to couple to the decomposition chamber housing 108. The first portion 220 may include a first outer edge 222 that couples to the decomposition chamber housing 108. For example, the first outer edge 222 may be coupled to the decomposition chamber housing 108 via welding, adhesive, fasteners, or the like. The mixer 200 may be coupled to the decomposition chamber housing 108 via the first portion 220 of the mixer body 210. In some embodiments, as illustrated in FIGS. 12 and 13, the decomposition chamber housing 108 and the mixer 200 are -16- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 coaxial. In other embodiments, the decomposition chamber housing 108 and the mixer 200 are non-coaxial. As illustrated in FIG. 13, the first portion 220 may be radially centered along the inlet aperture center axis 157. In some embodiments, as illustrated in FIG. 12, the first portion 220 is disposed along a plane that is orthogonal to the mixer body center axis 212 (i.e., the plane forms a 90 degree, or approximately 90 degree, angle with the mixer body center axis 212). In other embodiments, the first portion 220 is disposed along a plane that is non-orthogonal to the mixer body center axis 212 (i.e., the plane forms a non-90 degree angle with the mixer body center axis 212). For example, the plane the first portion 220 is disposed along may define an angle with the mixer body center axis 212 that is greater than or less than 90 degrees. In some embodiments, as illustrated in FIGS. 9-11, the first portion 220 has a flat surface. In these embodiments, the flat surface of the first portion 220 may allow the mixer body 210 to cover less volumetric space within the decomposition chamber housing 108, which may allow the decomposition chamber housing 108 to cover less volumetric space, thereby allowing for the exhaust aftertreatment system 100 to be more compact, reducing cost (e.g., by reducing quantity of materials, etc.), improving fuel efficiency (e.g., by reducing weight of vehicle carrying the exhaust aftertreatment system 100, etc.), and the like. In other embodiments, the first portion 220 has a curved surface. In some embodiments, the first portion 220 includes an aperture, a louver, or the like, to reduce backpressure. In other embodiments, the first portion 220 does not include apertures (e.g., the first portion 220 is solid, extends continuously, unperforated, etc.) to minimize or prevent the exhaust from bypassing the first portion 220, thereby encouraging the exhaust to swirl and mix with the treatment fluid. The mixer body 210 includes a second portion 230 coupled to the first portion 220. As illustrated in FIG. 13, the second portion 230 may be radially centered along the inlet aperture center axis 157 (e.g., the inlet aperture center axis 157 extends through a center of the second portion 230 such that the second portion 230 is evenly split by the inlet aperture center axis 157 in a circumferential direction). In a plan view, the inlet aperture 155 overlaps the second portion 230 such that the second portion 230 is configured to contact the fluid (e.g., the -17- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 exhaust, the treatment fluid, mixture of the exhaust and the treatment fluid, etc.) received via the inlet aperture 155 and disturb a flow of the fluid to encourage formation of swirling, thereby enhancing mixing between the exhaust and the treatment fluid. The second portion 230 extends from the first portion 220 in a direction axially away from the heater 146, such that the fluid flow is encouraged to mix within the decomposition chamber housing 108 before flowing downstream towards the heater 146. The second portion 230 has a first edge 232 at the first portion 220. The first portion 220 may extend radially outward from the first edge 232. As illustrated in FIGS. 12 and 13, the first edge 232 has a first radius R1. The second portion 230 also has a second edge 234 opposite the first edge 232. The second edge 234 has a second radius R2 that is less than the first radius R1 of the first edge 232 (e.g., R2 < R1). At least one of the first edge 232 or the second edge 234 has an arc angle Aୟgreater than 0 degree and less than 360 degrees. For example, in some embodiments, each of the first edge 232 and the second edge 234 has the arc angle Aୟbetween 170 degrees and 210 degrees, inclusive. In these embodiments, the arc angle Aୟbetween 170 degrees and 210 degrees may maximize decrease in pressure drop in the decomposition chamber housing 108 while maximizing swirling of the fluid to enhance mixing. In other embodiments, one of the first edge 232 or the second edge 234 has the arc angle Aୟbetween 170 degrees and 210 degrees, inclusive. In yet other embodiments, when the arc angle Aୟis set to greater than 180 degrees, it improves swirling and mixing characteristics. In some embodiments, as illustrated in FIGS. 9-11, the second portion 230 does not include apertures (e.g., the second portion 230 is solid, extends continuously, unperforated, etc.) to minimize or prevent the exhaust from bypassing the second portion 230, thereby encouraging the exhaust to swirl and mix with the treatment fluid. In other embodiments, the second portion 230 includes at least one aperture. In some embodiments, the second portion 230 has a first partial frustoconical shape. In other embodiments, the second portion 230 has a non-frustoconical shape, such as a cylindrical shape, a spherical shape, a semi-spherical shape, a conical shape, a prismatic shape, or the like. The second portion 230 may extend from the first portion 220 at a first angle A1 relative to the first portion 220 in a counterclockwise direction from the first portion 220 to the second portion 230. In some embodiments, the first -18- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 angle A1 is between 100 degrees and 130 degrees, inclusive, such that the second portion 230 does not restrict incoming fluid flow and does not negatively affect distribution of the exhaust and the treatment fluid downstream of the mixer 200 (i.e., at an inlet of the heater 146, at an inlet of the catalyst member 138, etc.). In other embodiments, the first angle A1 is less than 100 degrees or greater than 130 degrees. The mixer body 210 includes a third portion 240. The third portion 240 extends from the second edge 234 of the second portion 230 in a direction at least partially along the mixer body center axis 212. The third portion 240 includes an second outer edge 242 opposite the second edge 234 of the second portion 230. In some embodiments, the third portion 240 has a cylindrical shape or a second partial frustoconical shape. In other embodiments, the third portion 240 has a non-frustoconical shape, such as a cylindrical shape, a spherical shape, a semi-spherical shape, a conical shape, a prismatic shape, or the like. The third portion 240 extends from the second portion 230 at a second angle A2 relative to the mixer body center axis 212. In some embodiments, the second angle A2 is between 150 degrees and 270 degrees, inclusive, such that the third portion 240 does not restrict incoming fluid flow and does not negatively affect distribution of the exhaust and the treatment fluid downstream of the mixer 200 (i.e., at an inlet of the heater 146, at an inlet of the catalyst member 138, etc.). For example, the second angle A2 may be between 180 degrees, as illustrated in FIGS. 10 and 11, and 240 degrees, as illustrated in FIG. 9. In other embodiments, the second angle A2 is less than 170 degrees or greater than 260 degrees. As illustrated in FIG. 13, the third portion 240 may be radially centered along the inlet aperture center axis 157. The mixer body 210 may include additional portions before, after, or in-between the first portion 220, the second portion 230, and the third portion 240. The mixer 200 may include a wall 250. The wall 250 may be coupled to the mixer body 210. The wall 250 is configured to contact the fluid received via the inlet aperture 155 and disturb the flow of the fluid to encourage formation of swirling, thereby enhancing mixing between the exhaust and the treatment fluid. As illustrated in FIG. 13, the wall 250 may form a third angle A3 relative to the inlet aperture center axis 157. In some embodiments, the third -19- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 angle A3 is between 60 degrees (i.e., clockwise 60 degrees) and -60 degrees (i.e., counterclockwise 60 degrees), inclusive. For example, the third angle A3 may be between 40 degrees (i.e., clockwise 40 degrees), as illustrated in FIG. 9, and -40 degrees (i.e., counterclockwise 40 degrees), as illustrated in FIGS. 10 and 11, inclusive. In other embodiments, the third angle A3 is less than 60 degrees or greater than 60 degrees. In yet other embodiments, the third angle A3 is set such that the wall 250 is aligned perpendicular to the inlet conduit center axis 154. In some embodiments, the wall 250 extends radially outward from the second portion 230. In other embodiments, the wall 250 extends radially outward from both the second portion 230 and the third portion 240. In yet other embodiments, the wall 250 extends radially outward from first portion 220 or any combination of the first portion 220, the second portion 230, and the third portion 240. The wall 250 includes an edge 252. In some embodiments, as illustrated in FIGS. 9- 11, the edge 252 may be parallel to the mixer body center axis 212. In other embodiments, the edge 252 may be non-parallel to the mixer body center axis 212. As illustrated in FIGS. 12 and 13, the wall 250 may extend radially outward from the second portion 230 to the decomposition chamber housing 108. In some embodiments, the edge 252 may contact an inner surface of the decomposition chamber housing 108. As illustrated in FIG. 12, a first distance d1 may be defined between the mixer body center axis 212 and the first outer edge 222 of the first portion 220. The decomposition chamber housing 108 has an inner diameter D1 (e.g., a first reference diameter). The inner diameter D1 may be double the first distance d1 (i.e., D1 = 2d). The inner diameter D1 of the decomposition chamber housing 108 may be equal to, or approximately equal to, an outer diameter of the catalyst member 138. In some embodiments, the inner diameter D1 may be between 150 millimeter (mm) and 250 mm, inclusive. In other embodiments, the inner diameter D1 may be less than 150 mm or greater than 250 mm. The inlet aperture 155 of the decomposition chamber housing 108 has an aperture diameter D2 (e.g., a second reference diameter). In some embodiments, the aperture diameter -20- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079D2 is between 45% and 60% of the inner diameter D1, inclusive (e.g., 0.45^^^ ^ ^^ଶ ^ 0.6^^^).In other embodiments, the aperture diameter D2 is less than 45% of the inner diameter D1 or greater than 60% of the inner diameter D1. The first portion 220 has a first length L1 extending between the first outer edge 222 and the first edge 232 of the second portion 230. In some embodiments, the first length L1 isbetween 5% and 20% of the aperture diameter D2, inclusive (e.g., 0.05^^ଶ ^ ^^^ ^ 0.2^^ଶ). Inother embodiments, the first length L1 is less than 5% of the aperture diameter D2 or greater than 20% of the aperture diameter D2. The second portion 230 has a second length L2 extending between the first edge 232 and the second edge 234. In some embodiments, the second length L2 is between 60% and 85%of the aperture diameter D2, inclusive (e.g., 0.6^^ଶ ^ ^^ଶ ^ 0.85^^ଶ). In other embodiments, thesecond length L2 is less than 60% of the aperture diameter D2 or greater than 85% of the aperture diameter D2. In some examples, the second length L2 is between 50 mm and 95 mm, inclusive. In other examples, the second length L2 is less than 50 mm or greater than 95 mm. The third portion 240 has a third length L3. In some embodiments, the third lengthL3 is between 5% and 20% of the aperture diameter D2, inclusive (e.g., 0.05^^ଶ ^ ^^ଷ ^0.2^^ଶ). In other embodiments, the third length L3 is less than 5% of the aperture diameter D2 or greater than 20% of the aperture diameter D2. A second distance d2 may be defined between the inlet aperture 155 and the first outer edge 222 of the first portion 220. In some embodiments, the second distance d2 isbetween 2% and 15% of the aperture diameter D2, inclusive (e.g., 0.02^^ଶ ^ ^^ଶ ^ 0.15^^ଶ). Inother embodiments, the second distance d2 is less than 2% of the aperture diameter D2 or greater than 15% of the aperture diameter D2. The decomposition chamber housing 108 may include an end 264. The end 264 may be a point, an inner edge, an inner surface, or the like. A third distance d3 may be defined between the second outer edge 242 of the third portion 240 and the end 264. In some embodiments, the third distance d3 is between 30% and 60% of the aperture diameter D2, -21- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079inclusive (e.g., 0.3^^ଶ ^ ^^ଷ ^ 0.6^^ଶ). In other embodiments, the third distance d3 is less than30% of the aperture diameter D2 or greater than 60% of the aperture diameter D2. The mixer body 210 and the wall 250 are structured to alter the flow of the exhaust and / or the treatment fluid so that the mixer body 210 and the wall 250 cumulatively cause the exhaust to obtain a target flow distribution and / or the treatment fluid to obtain a target uniformity index (e.g., uniformity distribution, etc.) downstream of the mixer 200. Obtaining certain flow distributions and treatment fluid uniformities indices may be important in the operation of the exhaust aftertreatment system 100. For example, it may be desirable to obtain a uniform flow distribution and treatment fluid uniformity index at an inlet of the catalyst member 138 (i.e., when the catalyst member 138 is downstream of the mixer 200) because such a flow distribution allows the catalyst member 138 to obtain a relatively high NOXconversion efficiency. IV. Configuration of Example Embodiments While this specification 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 can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. As utilized herein, the terms “substantially,” “generally,” “approximately,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting -22- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the appended claims. The term “coupled” and the like, as used herein, mean the joining of two components directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two components or the two components and any additional intermediate components being integrally formed as a single unitary body with one another, with the two components, or with the two components and any additional intermediate components being attached to one another. The terms “fluidly coupled to” and the like, as used herein, mean the two components or objects have a pathway formed between the two components or objects in which a fluid, such as air, treatment fluid, an air-treatment fluid mixture, exhaust, hydrocarbon fluid, an air-hydrocarbon fluid mixture, may flow, either with or without intervening components or objects. Examples of fluid couplings or configurations for enabling fluid communication may include piping, channels, or any other suitable components for enabling the flow of a fluid from one component or object to another. It is important to note that the construction and arrangement of the various systems shown in the various example implementations is illustrative only and not restrictive in character. All changes and modifications that come within the spirit and / or scope of the described implementations are desired to be protected. It should be understood that some features may not be necessary, and implementations lacking the various features may be contemplated as within the scope of the disclosure, the scope being defined by the claims that follow. When the language “a portion” is used, the item can include a portion and / or the entire item unless specifically stated to the contrary. Also, the term “or” is used, in the context of a list of elements, in its inclusive sense (and not in its exclusive sense) so that when used to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at -23- 4902-7041-5634.1 Atty. Dkt. No.: 106389-9079 least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, 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). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated. Additionally, the use of ranges of values (e.g., W1 to W2, etc.) herein are inclusive of their maximum values and minimum values (e.g., W1 to W2 includes W1 and includes W2, etc.), unless otherwise indicated. Furthermore, a range of values (e.g., W1 to W2, etc.) does not necessarily require the inclusion of intermediate values within the range of values (e.g., W1 to W2 can include only W1 and W2, etc.), unless otherwise indicated. -24- 4902-7041-5634.1

Claims

Atty. Dkt. No.: 106389-9079 WHAT IS CLAIMED IS:

1. A mixer for an exhaust aftertreatment system, the mixer configured to receive exhaust from an exhaust conduit and a treatment fluid from an injector of a dosing module, the mixer comprising: a mixer body centered on a mixer body center axis, the mixer body comprising: a first portion configured to couple to a decomposition chamber housing, a second portion having a first edge at the first portion and having a first radius, and a second edge opposite the first edge and having a second radius less than the first radius, each of the first edge and the second edge having an arc angle between 170 degrees and 210 degrees, and a third portion extending from the second edge of the second portion in a direction at least partially along the mixer body center axis; and a wall coupled to the mixer body, the wall extending radially outward from the second portion.

2. The mixer of claim 1, wherein the wall comprises an edge parallel to the mixer body center axis.

3. The mixer of claim 1, wherein the wall extends radially outward from the second portion to the decomposition chamber housing.

4. The mixer of claim 1, wherein the first portion is disposed along a plane that is orthogonal to the mixer body center axis.

5. The mixer of claim 1, wherein the second portion does not include apertures.

6. The mixer of claim 1, wherein: the first portion has a flat surface; the second portion has a first partial frustoconical shape; and -25- 4902-7041-5634.1Atty. Dkt. No.: 106389-9079 the third portion has a cylindrical shape or a second partial frustoconical shape.

7. The mixer of claim 1, wherein: the second portion extends from the first portion at a first angle relative to the first portion between 100 degrees and 130 degrees, inclusive; and the third portion extends from the second portion at a second angle relative to the mixer body center axis between 150 degrees and 270 degrees, inclusive.

8. A mixing assembly for an exhaust aftertreatment system, the mixing assembly comprising: a decomposition chamber housing; and the mixer of claim 1, the mixer coupled to the decomposition chamber housing via the first portion.

9. The mixing assembly of claim 8, wherein the decomposition chamber housing and the mixer are coaxial.

10. The mixer of claim 1, wherein: ^^^ ൌ 2^^^;^^ଶ ^ 0.6^^^; and0.05^^ଶ ^ ^^^ ^ 0.2^^ଶ,where ^^^: a distance from the mixer body center axis to an outer edge of the first portion, ^^^: a first reference diameter, ^^ଶ: a second reference diameter, and ^^^: a length of the first portion.

11. The mixer of claim 1, wherein: ^^^ ൌ 2^^^;0.45^^^ ^ ^^ଶ ^ 0.6^^^; and-26- 4902-7041-5634.1Atty. Dkt. No.: 106389-9079 0.6^^ଶ ^ ^^ଶ ^ 0.85^^ଶ,where ^^^: a distance from the mixer body center axis to an outer edge of the first portion, ^^^: a first reference diameter, ^^ଶ: a second reference diameter, and ^^ଶ: a length of the second portion.

12. The mixer of claim 1, wherein: ^^^ ൌ 2^^^;^ ^^^^: a distance from the mixer body center axis to an outer edge of the first portion, ^^^: a first reference diameter, ^^ଶ: a second reference diameter, and ^^ଷ: a length of the third portion.

13. The mixer of claim 1, wherein the first portion extends radially outward from the first edge of the second portion.

14. The mixer of claim 1, wherein the wall extends radially outward from both the second portion and the third portion.

15. An exhaust aftertreatment system comprising: a decomposition chamber housing configured to receive exhaust from an engine; a dosing module comprising an injector configured to inject a treatment fluid into the decomposition chamber housing; a heater disposed at least partially within the decomposition chamber housing; and a mixer disposed upstream of the heater and configured to receive the exhaust and the treatment fluid, the mixer comprising: -27- 4902-7041-5634.1Atty. Dkt. No.: 106389-9079 a mixer body centered on a mixer body center axis, the mixer body comprising: a first portion coupled to the decomposition chamber housing, and a second portion having a first edge at the first portion and having a first radius, and a second edge opposite the first edge and having a second radius less than the first radius, each of the first edge and the second edge having an arc angle less than 360 degrees; and a wall coupled to the mixer body, the wall extending radially outward from the second portion.

16. The exhaust aftertreatment system of claim 15, wherein the mixer is disposed directly upstream of the heater.

17. The exhaust aftertreatment system of claim 15, wherein the mixer body further comprises a third portion extending from the second edge of the second portion in a direction at least partially along the mixer body center axis.

18. The exhaust aftertreatment system of claim 15, wherein the mixer is directly in contact with the heater.

19. The exhaust aftertreatment system of claim 15, wherein the second portion extends from the first portion in a direction axially away from the heater.

20. The exhaust aftertreatment system of claim 15, further comprising: a sensor configured to provide a signal associated with at least one of the exhaust or the treatment fluid; and a controller communicatively coupled to the sensor and the heater, the controller configured to: receive the signal from the sensor, determine a temperature of the at least one of the exhaust or the treatment fluid based on the signal, and -28- 4902-7041-5634.1Atty. Dkt. No.: 106389-9079 in response to determining that the temperature of the at least one of the exhaust or the treatment fluid is below a target fluid temperature, increase an operating temperature of the heater. -29- 4902-7041-5634.1

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