Patent Publication Number: US-10766044-B2

Title: Channeled reductant mixing device

Description:
TECHNICAL FIELD 
     The present disclosure is directed to an exhaust treatment system and, more particularly, to a nozzle that injects a reductant solution into a fluid path within an exhaust treatment system. 
     BACKGROUND 
     Internal combustion engines, such as diesel engines, gasoline engines, gaseous fuel-powered engines, and other engines known in the art, exhaust a complex mixture of components into the environment. These components may include nitrogen oxides (NOx), such as NO and NO 2 . Due to an increased focus on avoiding environmental pollution, exhaust emission standards are becoming more stringent, and in some instances, the amount of NOx emitted from engines may be regulated depending on engine size, engine class, and/or engine type. To ensure compliance with the regulation of these components, as well as reduce environmental effects, some engine manufacturers implement a strategy called Selective Catalytic Reduction (SCR). SCR is a process where gaseous and/or liquid reductant, most commonly urea ((NH 2 ) 2 CO), is selectively added to engine exhaust using one or more nozzles. The injected reductant decomposes into ammonia (NH 3 ), reacts with the NOx in the exhaust, and forms water (H 2 O) and diatomic nitrogen (N 2 ). 
     U.S. Pat. No. 8,356,473 to Blomquist, issued on Jan. 22, 2013 (hereinafter referred to as the &#39;473 reference), describes an injection device having a first conduit for supplying compressed gas, and a second conduit arranged on the outside of the second conduit for supplying a liquid agent. At least one hole extends between the first conduit and the second conduit. As discussed in the &#39;473 reference, liquid agent flows through the at least one hole into the compressed air. The liquid agent is atomized by the compressed gas, mixed with the compressed gas, and transported through an outlet of the injection device for dispersion into an exhaust line. 
     While the injection device of the &#39;473 reference may attempt to increase the atomization of the liquid agent, the operation of the injection device may be suboptimal. For example, the injection device described in the &#39;473 reference is relatively small in size, and due to low turbulence and mixing features, effective mixing of the liquid agent may be difficult to achieve. Further, the &#39;473 reference describes an injection device having multiple distinct and assembled parts, and such a device configuration may increase the size, complexity, assembly time, and/or manufacturing cost of the nozzle. Such multi-part devices are also often difficult to clean and may become clogged easily. 
     Example embodiments of the present disclosure are directed toward overcoming one or more of the deficiencies described above. 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the present disclosure, a nozzle, is described that includes a nozzle body. The nozzle body includes proximal end having a first inlet disposed in a direction along a longitudinal axis of the nozzle, and a second inlet having a first air inlet channel disposed at an angle perpendicular to the longitudinal axis of the nozzle. The nozzle includes a distal end disposed opposite the proximal end along the longitudinal axis of the nozzle, the distal end having an outlet. An interior of the nozzle is disposed between the proximal end and the distal end, and includes a fluid impingement chamber that is fluidly connected with the first inlet and the second inlet, and a mixing chamber fluidly connected with an outlet at the distal end. The nozzle also includes an impingement device fluidly connecting the fluid impingement chamber and the mixing chamber. The impingement device includes an impingement pin with a pin body and a convex surface disposed at an end of the impingement pin. The convex surface is concentric with the longitudinal axis of the nozzle. 
     According to another embodiment of the present disclosure, an impingement device includes an impingement pin and a device body coaxial with a longitudinal axis of the impingement pin. The device body is disposed to the impingement pin at a distal end of the impingement device. The impingement pin includes a convex surface at a proximal end of the device. The device body includes a first surface, a second surface opposite the first surface, and a plurality of inner channels connecting the first surface and the second surface. The plurality of inner channels are disposed in a first circular array at a first radial distance from a longitudinal axis of the impingement pin. The device body further includes a plurality of outer channels connecting the first surface and the second surface. The plurality of outer channels is disposed in a second circular array at a second radial distance from the longitudinal axis of the impingement pin. 
     According to yet another embodiment, an exhaust system is described. The exhaust system includes an exhaust pipe configured to receive exhaust from an engine, a compressed air source, a reductant source, and a nozzle fluidly connected with the exhaust pipe. The nozzle is configured to receive air from the compressed air source and reductant from the reductant source. The nozzle includes an impingement pin and a device body coaxial with a longitudinal axis of the impingement pin. The device body is disposed to the impingement pin at a distal end of the impingement device. The impingement pin includes a convex surface at a proximal end of the device. The device body includes a first surface, a second surface opposite the first surface, and a plurality of inner channels connecting the first surface and the second surface. The plurality of inner channels are disposed in a first circular array at a first radial distance from a longitudinal axis of the impingement pin. The device body further includes a plurality of outer channels connecting the first surface and the second surface. The plurality of outer channels is disposed in a second circular array at a second radial distance from the longitudinal axis of the impingement pin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a reductant nozzle of an exhaust system, according to an embodiment of the present disclosure. 
         FIG. 2  depicts a perspective view of a reductant impingement device for use in the reductant nozzle of  FIG. 1 , according to an embodiment of the present disclosure. 
         FIG. 3  depicts a top view of the reductant impingement device shown in  FIG. 2 , according to an embodiment of the present disclosure. 
         FIG. 4  is a front view of the reductant impingement device shown in  FIG. 2 , according to an embodiment of the present disclosure. 
         FIG. 5  depicts a section view of an inner channel of the reductant impingement device of  FIGS. 2-4 , according to an embodiment of the present disclosure. 
         FIG. 6  depicts a section view of an outer channel of the reductant impingement device of  FIGS. 2-4 , according to an embodiment of the present disclosure. 
         FIG. 7  is a schematic view of an exhaust system having a reductant nozzle, according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure generally relates to nozzles useful for injecting a mixture of reductant and air into an exhaust stream. Wherever possible, the same reference number(s) will be used through the drawings to refer to the same or like features. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. 
       FIG. 1  illustrates an example nozzle  100 . For the purposes of this disclosure, the nozzle  100  is shown and described in use with a diesel-fueled, internal combustion engine. However, the nozzle  100  may embody a reductant nozzle operative as part of any exhaust system useable with any other type of combustion engine such as a gasoline or a gaseous fuel-powered engine, or an engine fueled by compressed or liquefied natural gas, propane, or methane. 
     Selective Catalytic Reduction (SCR) is an active emissions control technology system that injects a liquid reductant agent through a catalyst into the exhaust stream of a diesel engine. The reductant source is usually automotive-grade urea, otherwise known as Diesel Exhaust Fluid (DEF). In some embodiments, the reductant may include DEF, an ammonia gas, liquefied anhydrous ammonia, ammonium carbonate, an ammine salt solution, a hydrocarbon such as diesel fuel, or another solution. In DEF reactions, the DEF sets off a chemical reaction that converts nitrogen oxides into nitrogen, water and tiny amounts of carbon dioxide (CO2), natural components of the air we breathe, which is then expelled through the vehicle tailpipe. Embodiments of the present disclosure may reduce emissions increasing the effectiveness of SCR systems in the emission control of diesel combustion engines. 
     An engine (not shown in  FIG. 1 ) may produce an exhaust stream  102 . The nozzle  100  may inject reductant into the exhaust stream  102 . The nozzle  100  is configured to spray a reductant solution (or other compound(s)) into the exhaust stream  102 . The nozzle  100  may include a proximal end  104  and a distal end  106  disposed opposite the proximal end  104 . The nozzle  100  may fluidly connect a supply line (not shown in  FIG. 1 ) that supplies reductant (not shown) to a first inlet  108 , which may be an inlet for reductant, at the proximal end  104  of the nozzle  100 , and via one or more fittings or couplers (not shown). The nozzle  100  may include a compressed air inlet channel  142  that can be fluidly connected to a supply of compressed air for supplying the compressed air  116  to a second inlet  110 . As explained in greater detail hereafter, the nozzle  100  may be configured to mix reductant solution  114  and compressed air  116  in extreme heat environments such that the reductant maintains an operative temperature without reductant crystallization that may clog the nozzle. 
     In some embodiments, the nozzle  100  may be manufactured using 3D printing techniques or other types of additive manufacturing (e.g., cast molding) and comprise a single piece of material. However, it is contemplated that one more of the components of the nozzle  100  discussed above and herein may be alternatively manufactured from other processes including manual machining, computer numeric controlled (CNC) machining, or with other methods. Additionally, the nozzle  100  may be manufactured from a plurality of materials, including chromium, nickel, stainless steel, alloys, ceramics, etc. The materials may also be anti-corrosive and anti-stick to prevent a build-up of the reductant on and/or within the nozzle  100 . 
     At the proximal end  104  of the nozzle  100 , the nozzle  100  may include one or more inlets configured to receive reductant and/or air from the first air inlet channel  142 . For example, the nozzle  100  may include a first inlet  108  for supplying the reductant solution  114  to the nozzle  100 , and a second inlet  110  for supplying compressed air  116  to the nozzle  100 . 
     In some examples, at the distal end  106  of the nozzle  100 , the nozzle  100  can include one or more spray channel outlet(s)  112 . According to embodiments described herein, a reductant/air solution  120  may enter the exhaust stream  102  through the one or more spray channel outlet(s)  112 . 
     As discussed in detail herein, the nozzle  100  may facilitate mixing of reductant solution  114  and compressed air  116  to mix, aerate, separate, and/or atomize the reductant solution  114 . According to an embodiment, an interior  118  of the nozzle  100  comprises a structure of the nozzle  100 , where the structure comprises various passages and channels formed at least partly by the body of the nozzle  100 . More particularly, within the nozzle interior  118  of the nozzle  100 , air and reductant may mix together to form the reductant/air solution  120 . This process may cause the reductant solution  114  to break up into fine particles or droplets at the interior first end  122  of the nozzle interior  118 , and mix with the compressed air  116  at an interior second end  124  of the nozzle interior  118 . As noted above, the nozzle  100  may disperse and/or otherwise direct the reductant/air solution  120  into the exhaust stream  102  through the one or more spray channel outlet(s)  112  disposed at the distal end  106  of the nozzle  100 . Accordingly, as the reductant/air solution  120  disperses into the exhaust stream  102 , the reductant/air solution  120  may react with NOx (e.g., NO and/or NO 2 ) to form water (H 2 O) and elemental nitrogen (N 2 ). 
     According to an embodiment, the nozzle interior  118  may be bifurcated into two or more main chambers (e.g., the fluid impingement chamber  426  and the mixing chamber  128 ) by an impingement device  130 . In some aspects, the impingement device  130  may fluidly connect the fluid impingement chamber  426  and the mixing chamber  128  via a plurality of orifices  138  that provide channels for the reductant/air solution  120  to pass from the fluid impingement chamber  426  to the mixing chamber  128 . More particularly, an impingement device body  132  may be configured as a substantially flat disk or plate having an impingement pin  134  at a center of the impingement device body  132 , where the impingement device body  132  seals against one or more mating surfaces such that reductant solution  114 , compressed air  116 , and/or reductant/air solution  120  may not pass through the impingement device  130  from the fluid impingement chamber  426  to the mixing chamber  128  except for through the plurality of orifices  138 . 
     As explained in greater detail hereafter, the impingement pin  134  includes a convex surface  136  at a proximal end of the impingement device  130 . In operation, the reductant solution  114  may be pumped or otherwise conveyed into the first inlet  108 . Accordingly, when pumped into the nozzle  100 , the reductant solution  114  travels through first inlet  108  and strikes the convex surface  136 , where an approximate center of a laminar flow of the reductant solution  114  (the reductant solution  114  and the laminar flow of the reductant solution  114  depicted as an arrow in  FIG. 1 ) strikes the convex surface  136  (approximately) at the apex of the convex surface  136 . 
     The shape and position of the convex surface  136  is such that upon impinging the convex surface  136 , the reductant solution  114  is dispersed into a mixture of ambient air and reductant solution. In some aspects, the orifices  138 , which connect the fluid impingement chamber (where the fluid is broken up by the impingement pin  134 ) and the mixing chamber  128 , are configured to further disperse the reductant and compressed air solution into smaller discrete droplets. For example, the orifices  138  can be configured to break the reductant/air mixture into droplets, atomize the reductant and air solution in part, or otherwise reduce the reductant and solution into an aerosol/droplet mixture. As explained in detail hereafter, the orifices  138  may also be configured to create turbulence in the mixing chamber  128  to further combine the compressed air  116  and the reductant solution  114 , and form the reductant/air solution  120 . 
     When the reductant solution is urea or contains urea, in some instances, the urea may react with heat such that crystallization of the reductant solution can occur above certain temperatures. Because the nozzle  100  may be operable as part of an exhaust system of a combustion engine, the nozzle  100  can reach temperatures ranging between approximately 200° C. to approximately 500° C. In some examples, the urea-water solution of reductant solution may crystalize at these high temperatures (e.g., between approximately 200° C. and approximately 500° C.), as water evaporates from the solution. When the urea crystalizes at high temperatures, deposits of the urea may form that can hinder the performance of the exhaust system. For example, the selective-catalytic reaction that removes particulates from the exhaust stream may be hindered by the urea crystal deposits, the nozzle outlet or other fluid ports may become clogged, etc. 
     To prevent crystallization of the reductant solution  114 , according to an embodiment, the nozzle  100  may channel the compressed air  116  through a first air inlet channel  142 . The compressed air  116 , when mixed with the reductant solution  114 , may cool the system and prevent crystallization of the urea in the reductant solution  114 . Accordingly, the first air inlet channel  142  fluidly connects the second inlet  110  to the fluid impingement chamber  426 . The second inlet channel  110  may direct the compressed air  116  into the fluid impingement chamber  426  at a predetermined angle with respect to the longitudinal axis  140 . The predetermined angle of incidence of the compressed air  116  with respect to the impingement pin  134  may create a turbulent airflow within the fluid impingement chamber  126 . For example, the predetermined angle between an axis of the first air inlet channel  142  and the longitudinal axis  140  may be about 90° (substantially perpendicular). As depicted in  FIG. 1 , the first air inlet channel  142  may be disposed opposite to a pin body surface of the impingement pin  134  such that a longitudinal center of the first air inlet channel  142  is substantially perpendicular to a curved outer surface of the impingement pin  134 , and substantially perpendicular to the longitudinal axis  140 . When the compressed air  116  hits the side of the impingement pin  134  at the predetermined angle, the compressed air  116  may be forced to mix with the reductant solution  116  in a way that combines and cools the impingement pin  134 , the fluid impingement chamber  126 , and the reductant solution  114 . 
     In some aspects, the nozzle  100  may include two or more air inlet channels. For example, the nozzle  100  may include a second air inlet channel  144  disposed opposite to the pin body  135  of the impingement pin  134  such that a longitudinal center of the second air inlet channel may be substantially perpendicular to the outer surface of the pin body  135  of the impingement pin  134 , and substantially perpendicular to the longitudinal axis  140 . In yet another embodiment, more than two air inlet channels may be included at substantially perpendicular angles to the longitudinal axis  140 , such that they are configured to be opposite to the pin body  135 . As used herein, the phrase “opposite to the pin body  135 ” means that the pin body  135  may be configured to be directly in the laminar and/or turbulent flow of a fluid interacting with the pin body  135 . 
     By injecting the compressed air  116  at a perpendicular angle to the longitudinal axis  140 , the stream of compressed air  116  may interact with the curved exterior surface of the impingement pin  134  such that the compressed air  116  disperses at reflective angles within the fluid impingement chamber  426 . For example, the angle of incidence of the linearly-flowing stream of compressed air  116  equals the angle of reflection of the stream of compressed air  116  as the air stream interacts with the impingement pin  134 . Accordingly, when the radially curved pin body  135  interacts with the laminar flow of the stream of compressed air  116 , the angle of reflection of the compressed air  116  is spread throughout the fluid impingement chamber  126 . The turbulence caused by the compressed air  116  interacting with the curved pin body  135   f  mixes the compressed air  116  with the reductant solution  114  within the fluid impingement chamber  426 . In combination with the dispersed reductant solution  114  (dispersed after hitting the convex surface  136 ), the reductant solution  114  may be cooled by the compressed air  116 , which may be more turbulent and evenly mixed with the reductant solution  114 . Because of the turbulence created by the combination/configuration of the first air inlet channel  142  and the reductant solution  114  interacting with the convex surface  136 , the interior surfaces of the nozzle interior  118  may also be cooled to a temperature below the threshold for urea crystallization. 
     The nozzle  100  may be installed directly in the exhaust stream  102  of an exhaust system (e.g., as shown in  FIG. 7 , discussed in greater detail hereafter), in conventional SCR catalyst systems. Accordingly, in conventional emission systems a nozzle spraying diesel emission fluid (DEF) may build crystal deposits of urea, which can foul the exhaust system. In conventional systems, the nozzle can exceed the crystallization threshold of temperature for urea in the reductant solution  114 . According to one or more embodiments, a combination of elements may provide optimal cooling and mixing properties: first, the compressed air  116  may be forced into the impingement pin  134  at an angle with respect to the impingement pin  134  that creates turbulence, and second, the reductant solution  114  may be interspersed with the turbulent air by the convex surface  136  within the fluid impingement chamber  426  such that the outer surface of the pin body of the impingement pin  134  may directly oppose the stream of compressed air  116 . According to embodiments, this configuration the nozzle  100  configuration may cool both the reductant solution  114  and the nozzle interior  118 . 
       FIG. 2  depicts a perspective view of an example impingement device  130  for use in the reductant nozzle of  FIG. 1 , according to an embodiment of the present disclosure.  FIG. 3  depicts a top view of the impingement device  130  shown in  FIG. 2 , according to an embodiment of the present disclosure.  FIG. 4  is a front view of the impingement device  130  shown in  FIG. 2 , according to an embodiment of the present disclosure. 
     With reference to  FIG. 3 , according to one or more embodiments, the impingement device  130  may include an impingement device body  132 , and the impingement pin  134  disposed to the impingement device body  132 . The impingement device body  132  includes the orifices  138 , which may be circumferentially disposed around the longitudinal axis  140  of the nozzle ( FIG. 1 ), and more specifically, disposed around a second longitudinal axis (longitudinal axis  150 , as shown in  FIG. 4 ) of the impingement device  130 . When the impingement pin  134  is configured as an assembly with the nozzle  100  (for example, as depicted in  FIG. 1 ), the longitudinal axis  140  and second longitudinal axis  150  are colinear. 
     As shown in  FIG. 2 , the orifices  138  may be configured as through-channels circumferentially disposed around the second longitudinal axis  150 . In one aspect, the plurality of orifices  138  are substantially equally circumferentially distributed around the longitudinal axis  140  of the nozzle  100  (and substantially equally circumferentially distributed around the second longitudinal axis  150 ). 
     In another aspect, the orifices  138  may be configured as two radial groupings such that one grouping of channels may be at a first radial distance  154  and the second grouping may be organized at a second radial distance  158 . For example, a plurality of inner channels  152  may be disposed in circular array at the first radial distance  154  from the second longitudinal axis  150 , and a plurality of outer channels  156  are disposed in a circular array at the second radial distance  158  from the second longitudinal axis  150  of the impingement pin  134 . In one aspect, the first radial distance may be approximately ⅓ of the radial distance of the impingement device body  132  from the second longitudinal axis  150  to an outer edge of the impingement device body  132 . In another aspect, the second radial distance may be approximately ⅔ of the radial distance of the impingement device body  132  from the second longitudinal axis  150  to an outer edge of the impingement device body  132 . In other examples, the distance may be greater than or less than the radial distance of the impingement device body  132 , such as, for example, ½ of the radial distance, 11/16 of the radial distance, etc. 
     With reference to the front view of the impingement pin  134  in  FIG. 4 , the pin body  135  of the impingement pin  134  is depicted with the convex surface  136  at a proximal end  146  of the pin body  135 . The convex surface  136  of the impingement device  130  may be configured to oppose a flow direction of a fluid flow of the first inlet  108  of the nozzle  100  ( FIG. 1 ). The convex surface  136  may be substantially hemispherical, according to an embodiment. The hemispherical shape is shown to disperse the reductant solution  114  ( FIG. 1 ) in a way such that mixing of the reductant solution  114  with the compressed air  116  results in optimal cooling of the reductant/air solution  120 . 
     Another benefit of the convex surface  136  may be ease of manufacture of the impingement device  130 . In some embodiments, the impingement pin  134  may be machined from or otherwise manufactured as a unitary piece with respect to the impingement device body  132 . In another embodiment, the impingement pin  134  may be a separate part from the impingement device body  132 , and removably disposed to the impingement device body  132  using a mechanical fastener (not shown). In either case, the convex surface  136  may provide an optimal dispersing affect without introduction of multiple machining steps or extraneous parts to assemble. 
     With continued reference to  FIG. 4 , a first surface  147  may be configured to seal against an interior lip of the nozzle interior  118  such that the fluid impingement chamber  426  may be fluidly separate from the mixing chamber  128 , except for the orifices  138  (which include plurality of inner channels  152 , and the plurality of outer channels  156 ). With reference to  FIG. 3 , a partial top view of the orifices  138  is depicted (and more particularly, an inner channel  160 , and an outer channel  162 , of the orifices  138  is depicted). For the sake of simplicity of explanation, the top view in  FIG. 3  shows only one inner channel  160  and one outer channel  162 , although it should be appreciated that the plurality of channels (the orifices  138 ) may include any number of channels. 
     The inner channel  160  may be configured to direct fluid (e.g., the reductant solution  114 , the compressed air  116 , and/or the reductant/air solution  120 ) in a direction generally consistent with a channel direction  164 . The outer channel  162  may be configured to direct fluid (e.g., the reductant solution  114 , the compressed air  116 , and/or the reductant/air solution  120 ) in a direction generally consistent with a directional arrow showing a channel direction  166 . The inner channel  160  may be representative of the channel direction for all of the inner channels of the plurality of orifices  138  circumferentially disposed around the second longitudinal axis  150 . The inner channel  160  fluidly connects the first surface  147  and the second surface  149 . 
     According to another embodiment, the channel direction  164  and the channel direction  166  may be configured in another pattern such that the direction changes at every two channels, every three channels, etc. within the same radial distance. Other configurations are contemplated. 
       FIG. 5  depicts a section view of an inner channel of the reductant impingement device of  FIGS. 2-4 , according to an embodiment of the present disclosure. The channel direction  164  indicates a general trajectory of any fluids passing through the inner channel  160 . The inner channel  160  may be configured as a slit having two opposing inner channel walls. In one embodiment, the two inner channel walls can include a first inner channel wall  168  that may be disposed substantially parallel to a second inner channel wall  170 . The two opposing channel walls form two sides of the inner channel  160 . In one aspect, the first inner channel wall  168  and the second inner channel wall  170  are disposed at a first predetermined angle  172  with respect to the longitudinal axis of the impingement pin  134  (e.g., the second longitudinal axis  150 ). In one aspect, the first predetermined angle may be approximately 30° in another aspect, the first predetermined angle may be another angle such as, for example, 25°, or 35°, or greater or less than 25°, or 35°. 
       FIG. 6  depicts a section view of an outer channel of the reductant impingement device of  FIGS. 2-4 , according to an embodiment of the present disclosure. The impingement device body  132  depicts a section view (Section B) of the outer channel  162 , according to an embodiment. The channel direction  166  indicates a general trajectory of any fluids passing through the outer channel  162 . The outer channel  162  may be configured as a slit having two opposing inner channel walls. In one embodiment, the two outer channel walls can include a first outer channel wall  174  that may be disposed substantially parallel to a second outer channel wall  176 . The two opposing channel walls form two sides of the outer channel  162 . In one aspect, the first outer channel wall  174  and the second outer channel wall  176  are disposed at a second predetermined angle  178  respective to the longitudinal axis of the impingement pin  134  (e.g., the second longitudinal axis  150 ). In one aspect, the second predetermined angle may be approximately 30°. In another aspect, the first predetermined angle may be another angle such as, for example, 25°, or 35°, or greater or less than 25°, or 35°. Notably, the channel direction  164  ( FIG. 5 ), which depicts the fluid trajectory of fluids passing through the plurality of inner channels  152 , may be opposite to the channel direction  166 , which depicts the fluid trajectory of fluids passing through the plurality of outer channels  156 . 
       FIG. 7  is a schematic view of an exhaust system  180  for an engine  188  that includes the nozzle  100 , according to an embodiment of the present disclosure. The exhaust system  180  may further include an air compressor or other compressed air source  182  configured to supply compressed air  116  via a compressed air supply line  190 , and one or more reservoirs and pumps configured as a reductant source  184 . The reductant source  184  may be, for example, a DEF tank configured to supply the reductant solution  114  via a reductant solution supply line  186 . The reductant solution supply line  186  may be fluidly connected with the first inlet  108  ( FIG. 1 ). 
     In some embodiments, an amount of compressed air  116  and/or an amount of reductant solution  114  supplied to the system may be associated with a flow rate of the exhaust stream  102 , an operational state of the engine  188  (e.g., rpm), a temperature of the exhaust stream  102 , a concentration of a particular gas in the exhaust stream  102 , and/or one or more other operating conditions of the exhaust system  180 . For example, as the flow rate of the exhaust stream  102  decreases, a controller or other control component (not shown) operably connected to an air compressor and/or reductant pump may control the pump to commensurately decrease the amount of reductant solution  114  and/or compressed air  116  supplied to the nozzle  100  (and thereby introduced into the exhaust stream  102 ). Alternatively, as the flow rate of the exhaust stream  102  increases, a controller or other control component (not shown) may increase and/or decrease the amount of reductant solution  114  and/or compressed air  116  supplied to the nozzle  100 . Consequently, the amount of reductant/air solution  120  introduced into the exhaust stream  102  may be controllable by a controller. 
     In some embodiments, the nozzle  100  may be located downstream from a SCR system, or be operable as part of a SCR system within an exhaust pipe  192  and/or other treatment systems. The exhaust system  180  may also include one or more oxidation catalysts, mixing features, particulate filters (e.g., diesel particulate filter (DPF)), SCR substrates, ammonia reduction catalysts, and other devices configured to further enhance the effectiveness of reducing NOx (devices not shown). Additionally, while only one nozzle  100  is shown, in some embodiments, the exhaust system  180  may include more than one nozzle  100 . Moreover, the exhaust system  180  may include any number of exhaust pipes  192  having one or more nozzles  100  positioned therein. 
     INDUSTRIAL APPLICABILITY 
     The nozzle  100 , impingement device  130 , and exhaust system  180  may increase exhaust system efficiency and operability by decreasing and/or eliminating crystallization of urea compounds or other reactants due to adverse response to exhaust system heat. The embodiments described herein may increase turbulence and mixing within the nozzle  100  such that reductant solution  114  may be maintained at operable temperatures while treating the exhaust stream  102  in an exhaust system of a combustion engine. 
     While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof