Patent Publication Number: US-2016245142-A1

Title: Reductant injector mount

Description:
TECHNICAL FIELD 
     The present disclosure relates to an injector mount, and more particularly to a reductant injector mount associated with an aftertreatment system of an engine. 
     BACKGROUND 
     An aftertreatment system is associated with an engine system. The aftertreatment system is configured to treat and reduce oxides of nitrogen (NOx) present in an exhaust gas flow, prior to the exhaust gas flow exiting into the atmosphere. In order to reduce NOx, the aftertreatment system may include a reductant delivery module, a reductant injector, and a Selective Catalytic Reduction (SCR) module. 
     The reductant injector is configured to inject a reductant into the exhaust gas flowing through a mixing tube of the aftertreatment system. The reductant may include urea. In order to achieve improved levels of NOx conversion, better flow distribution and mixing of the reductant with the exhaust gases must be achieved. A mixing system is affixed inside the mixing tube so that increased turbulence and improved distribution of the reductant within the exhaust gases may be achieved within a length of the mixing tube. 
     A reductant injector mount is used to couple the reductant injector to the mixing tube. However, urea deposit formation may take place in an area near to an injection point of the reductant injector. Such urea deposition may hinder or prevent reductant spray and/or interaction with the exhaust gas flow, and may also cause a reduction in NOx conversion in the aftertreatment system. 
     U.S. Pat. No. 8,079,211 describes systems and methods provided for injecting liquid reductant into an engine exhaust. In one example, the system includes a gas deflector positioned upstream of an injector where the gas deflector is configured to create a high pressure zone upstream of the deflector and a low pressure zone downstream of the deflector surrounding the injector outlet. A bypass flow passage diverts exhaust flow from the high pressure zone upstream of the deflector to allow the bypassed portion of exhaust to flow into the exhaust gas stream to form a gas shield for a liquid reductant spray from the injector. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect of the present disclosure, a reductant injector mount is provided. The reductant injector mount includes a mounting region configured to connect to an exhaust conduit. The reductant injector also includes a contoured region formed in the mounting region. The contoured region is configured to increase a velocity of an exhaust gas flow through the contoured region. The contoured region is also configured to reduce a recirculation of the exhaust gas flow through the contoured region. Further, the reductant injector mount includes a cut out portion provided on the contoured region. The cut out portion is configured to receive a reductant injector tip therethrough. 
     In another aspect of the present disclosure, an aftertreatment system is provided. The aftertreatment system includes an exhaust conduit having a cut out region. The aftertreatment system also includes a selective catalytic reduction module coupled to the exhaust conduit. The aftertreatment system further includes a reductant injector mount disposed on the exhaust conduit. The reductant injector mount is positioned upstream of the selective catalytic reduction module with respect to an exhaust gas flow. The reductant injector mount includes a mounting region connected to the exhaust conduit. The reductant injector mount also includes a contoured region formed in the mounting region. The contoured region faces an inner side of the exhaust conduit. The contoured region is configured to increase a velocity of the exhaust gas flow through the contoured region. The contoured region is also configured to reduce a recirculation of the exhaust gas flow through the contoured region. Further, the reductant injector mount includes a cut out portion provided on the contoured region. The aftertreatment system includes a reductant injector in fluid communication with the exhaust conduit, wherein the reductant injector mount is received through the cut out portion provided on the reductant injector mount. 
     In yet another aspect of the present disclosure, a method of controlling an exhaust gas flow in an exhaust conduit is provided. The method includes receiving a reductant injector through a mounting region of a reductant injector mount. The method also includes flowing an exhaust gas flow on a contoured region of the reductant injector mount. The method further includes increasing a velocity of the exhaust gas flow through the contoured region based on the flow. The method includes reducing a recirculation of the exhaust gas flow through the contoured region based on the flow. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an exemplary machine, according to one embodiment of the present disclosure; 
         FIG. 2  is a schematic view of an exemplary engine system associated with the machine, according to one embodiment of the present disclosure; 
         FIG. 3  is a perspective view of a portion of an aftertreatment system associated with the engine system; 
         FIG. 4  is a perspective view of a reductant injector mount, according to one embodiment of the present disclosure; 
         FIG. 5  is a cross sectional view of the reductant injector mount and a reductant injector received therein; 
         FIG. 6  is a cross sectional view of the reductant injector mount of  FIG. 4 ; 
         FIGS. 7 to 9  are perspective views of reductant injector mounts, according to various embodiments of the present disclosure; and 
         FIG. 10  is a flowchart for a method of controlling exhaust gas flow in an exhaust conduit. 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. An exemplary embodiment of a machine  100 , according to the present disclosure is shown in  FIG. 1 . The machine  100  may be a mining truck, as shown, or may include any off-highway or on-highway vehicle using a fuel-powered engine, as described herein. The machine  100  generally includes a machine frame  102  for supporting, among other systems and components, an engine system  104  (see  FIG. 2 ) which will be discussed in greater detail in connection with  FIG. 2 . 
     The machine  100  also includes a plurality of ground-engaging elements  106 , in this case being wheels. As should be appreciated by one of ordinary skill in the art, an engine  108  (see  FIG. 2 ) of the engine system  104  may provide propulsion power for the ground-engaging elements  106  and may power a variety of other machine systems, including various mechanical, electrical, and hydraulic systems and/or components. Further, the machine  100  may also include an operator control station  110 , including a variety of operator controls and displays useful for operating the machine  100  and/or a dump body  112  which may be pivotal relative to the machine frame  102 . 
     Referring to  FIG. 2 , a schematic diagram of the engine system  104  is illustrated, according to one embodiment of the present disclosure. The engine system  104  includes the engine  108 , which may be an internal combustion engine, such as, a reciprocating piston engine or a gas turbine engine. The engine  108  may be a spark ignition engine or a compression ignition engine, such as, a diesel engine, a homogeneous charge compression ignition engine, or a reactivity controlled compression ignition engine, or other compression ignition engines known in the art. The engine  108  may be fueled by gasoline, diesel fuel, biodiesel, dimethyl ether, alcohol, natural gas, propane, hydrogen, combinations thereof, or any other combustion fuel known in the art. 
     The engine  108  may include other components (not shown), such as, a fuel system, an intake system, a drivetrain including a transmission system, and so on. The engine  108  may be used to provide power to any machine including, but not limited to, an on-highway truck, an off-highway truck, an earth moving machine, an electric generator, and so on. Accordingly, the engine system  104  may be associated with an industry including, but not limited to, transportation, construction, agriculture, forestry, power generation, and material handling. 
     Referring to  FIG. 2 , the engine system  104  includes an aftertreatment system  114  fluidly connected to an exhaust manifold of the engine  108 . The aftertreatment system  114  is configured to treat an exhaust gas flow exiting the exhaust manifold of the engine  108 . The exhaust gas flow contains emission compounds that may include oxides of nitrogen (NOx), unburned hydrocarbons, particulate matter, and/or other combustion products known in the art. The aftertreatment system  114  may be configured to trap or convert NOx, unburned hydrocarbons, particulate matter, combinations thereof, or other combustion products present in the exhaust gas flow, before exiting the engine system  104 . 
     In the illustrated embodiment, the aftertreatment system  114  includes a first module  116  that is fluidly connected to an exhaust conduit  118  of the engine  108 . During engine operation, the first module  116  is arranged to internally receive engine exhaust gas from the exhaust conduit  118 . The first module  116  may contain various exhaust gas treatment devices, such as, a Diesel Oxidation Catalyst (DOC)  120  and a Diesel Particulate Filter (DPF)  122 , but other devices may be used. The first module  116  and the components found therein are optional and may be omitted for various engine applications in which the exhaust treatment function provided by the first module  116  is not required. 
     In the illustrated embodiment, the exhaust gas flow provided to the first module  116  by the engine  108  may first pass through the DOC  120  and then through the DPF  122  before entering a conduit  123 . The conduit  123  includes a mixing tube  124 . Further, the aftertreatment system  114  includes a reductant supply system  126 . A reductant is injected into the mixing tube  124  by a reductant injector assembly  127 . The reductant injector assembly  127  may include one or more reductant injectors  128  (see  FIG. 3 ). The reductant may be a fluid, such as, Diesel Exhaust Fluid (DEF). The reductant may include urea, ammonia, or other reducing agent known in the art. 
     The reductant supply system  126  includes a reductant tank  130 . The reductant is contained within the reductant tank  130 . Parameters related to the reductant tank  130  such as size, shape, location, and material used may vary according to system design and requirements. Further, the reductant injector  128  may be communicably coupled to a controller (not shown). Based on control signals received from the controller, the reductant from the reductant tank  130  is provided to the reductant injector  128  by a pump assembly  132 . As the reductant is injected into the mixing tube  124 , the reductant mixes with the exhaust gas flow passing therethrough, and is carried to a second module  134 . Further, the conduit  123  is configured to fluidly interconnect the first module  116  with the second module  134 , such that, the exhaust gas flow from the engine  108  may pass through the first and second modules  116 ,  134  in series before being released at a stack  136  connected downstream of the second module  134 . 
     The second module  134  encloses a Selective Catalytic Reduction (SCR) module  138  and an Ammonia Oxidation Catalyst (AMOX)  140 . The SCR module  138  operates to treat exhaust gases exiting the engine  108  in the presence of ammonia, which is provided after degradation of a urea-containing solution injected into the exhaust gas flow in the mixing tube  124 . The AMOX  140  is used to convert any ammonia slip from the downstream flow of the SCR module  138  before exiting the stack  136 . 
       FIG. 3  illustrates a partial cutaway perspective view of a portion of the conduit  123  shown in  FIG. 2 , depicting the mixing tube  124  and the SCR module  138  located downstream of the conduit  123 , according to one embodiment of the present disclosure. In order to promote mixing of the reductant with the exhaust gas flow, a mixing system  142  may be associated with the aftertreatment system  114 . The mixing system  142  is provided within the portion of the mixing tube  124 . The mixing system  142  may be positioned downstream of the reductant injector assembly  127  and upstream of the SCR module  138 . The mixing system  142  includes a plurality of mixing elements  144 . The mixing elements  144  may include same or different type of mixing elements. For example, the mixing elements  144  may include flapper mixers, swirl mixers, impingement mixers, and the like. The amount of the reductant that may be injected into the mixing tube  124  may be appropriately metered based on engine operating conditions. 
     The aftertreatment system  114  disclosed herein is provided as a non-limiting example. It will be appreciated that the aftertreatment system  114  may be disposed in various arrangements and/or combinations relative to the exhaust manifold. These and other variations in aftertreatment system design are possible without deviating from the scope of the disclosure. 
     Reductant injector mounts  200 ,  202  are associated with the aftertreatment system  114 . The reductant injector mounts  200 ,  202  are positioned upstream of the SCR module  138  with respect to an exhaust gas flow direction “F”. Further, the reductant injector mounts  200 ,  202  are attached to a top portion  146  of the mixing tube  124 . The reductant injector mounts  200 ,  202  may be attached to the mixing tube  124  using a joining process, such as welding. Alternatively, any joining process, such as brazing, soldering, may be used. Further, mechanical fasteners or an adhesive may also be used for attaching the reductant injector mounts  200 ,  202  to the mixing tube  124 . As shown in the accompanying figures, the reductant injector mounts  200  are disposed in a direction parallel to the exhaust gas flow direction “F”. Whereas, the reductant injector mounts  202  are disposed in an angular orientation with respect to the exhaust gas flow direction “F”. The reductant injector mount  200 ,  202  is configured to mount the reductant injector  128  onto the mixing tube  124 . A number of the reductant injector mounts  200 ,  202  may depend on a number of the reductant injectors  128  associated with the aftertreatment system  114 , and may vary based on system requirements. 
     The mixing tube  124  of the present disclosure includes two reductant injectors  128  associated therewith. Therefore, the mixing tube  124  includes two reductant injector mounts  200 ,  202  mounted to the top portion  146  of the mixing tube  124 . It should be noted that the number of reductant injectors and the reductant injector mounts may vary. In one example, four reductant injectors and the corresponding reductant injector mounts may be provided on the mixing tube  124 . The design of the reductant injector mount  200  will now be explained with reference to  FIGS. 4-6 . 
     Referring to  FIGS. 3, 4, and 5 , the reductant injector mount  200  has a substantially rectangular shape. The reductant injector mount  200  defines an axis A-A′. The axis A-A′ is parallel to the exhaust gas flow direction “F”. Alternatively, the reductant injector mount  200  may be square, circular, or elliptical in shape. The reductant injector mount  200  includes a stepped design. When mounted on the mixing tube  124 , a first portion  404  of the reductant injector mount  200  may project from the top portion  146  of the mixing tube  124 . Whereas a second portion  406  (see  FIG. 4 ) of the reductant injector mount  200  may project into an interior space  409  the mixing tube  124 . Further, the top portion  146  of the mixing tube  124  includes a cut out region  413  (see  FIG. 3 ). The cut out region  413  is configured to receive the second portion  406  of the reductant injector mount  200 , in order to attach the reductant injector mount  200  with the mixing tube  124 . The cut out region  413  has a rectangular shape with rounded edges. It should be noted that the shape of the cut out region  413  may vary based on the shape of the reductant injector mount  200 . 
     The reductant injector mount  200  includes a mounting region  402 . The mounting region  402  is configured to be connected to and in contact with the mixing tube  124 . The mounting region  402  referred to herein collectively refers to the top surface  405  of the first portion  404  and the second portion  406  facing the exhaust gas flow. 
     The mounting region  402  of the reductant injector mount  200  may include a plurality of receiving elements  408 . In the illustrated embodiment, the reductant injector mount  200  includes three receiving elements  408 . However, a number of the receiving elements  408  may vary as per system requirements. The receiving elements  408  project from the mounting region  402  of the reductant injector mount  200 . 
     In one example, the receiving elements  408  are configured to receive mechanical fasteners (not shown) of the reductant injector  128 , in order to couple the reductant injector  128  to the reductant injector mount  200 . The receiving elements  408  include apertures  411  (see  FIG. 6 ). In the illustrated embodiment, the apertures  411  are embodied as blind holes. Alternatively, the apertures  411  may be embodied as through-holes. In one embodiment, the receiving elements  408  may be integral with the reductant injector mount  200 . Alternatively, the receiving elements  408  may be formed as a separate component and later assembled with the reductant injector mount  200 . When the reductant injector mount  200  is coupled to the mixing tube  124 , the receiving elements  408  may project into the interior space  409  of the mixing tube  124 . 
     The reductant injector mount  200  includes a contoured region  410 . The contoured region  410  is formed in the mounting region  402 . The contoured region  410  is configured to provide a flow field for the exhaust gases flowing therethrough. The contoured region  410  is designed such that the contoured region  410  may increase a velocity of the exhaust gas flow through the contoured region  410 . The contoured region  410  may also be configured to reduce a recirculation of the exhaust gases flowing therethrough. The direction of the exhaust gas flow through the contoured region  410  is marked by arrows “F” in  FIG. 5 . 
     The reductant injector mount  200  includes a cut out portion  412 . The cut out portion  412  is provided on the contoured region  410  of the reductant injector mount  200 . More particularly, the cut out portion  412  is positioned in a throat portion  414  of the contoured region  410 . The cut out portion  412  is configured to receive a reductant injector tip  416  of the reductant injector  128  therethrough. As shown in  FIG. 4 , the cut out portion  412  is positioned closer to a downstream end  417  of the contoured region  410  with respect to the exhaust gas flow direction “F” as compared to an upstream end  418  of the contoured region  410 . A diameter “D” of the cut out portion  412  corresponds to a diameter of the reductant injector tip  416  of the reductant injector  128 . 
     As illustrated in  FIG. 6 , the cut out portion  412  of the contoured region  410  is configured to receive the reductant injector tip  416 . The reductant injector  128  may be provided with a gasket  420 . The gasket  420  may embody a metal clip gasket and may be configured to hold the reductant injector tip  416  in place. The gasket  422  may flush or protrude into the mixing tube  124 . An excessive protrusion of the gasket  422  and thereby the reductant injector tip  416  may lead to an improper injection and distribution of the reductant within the mixing tube  124 . Therefore, a depth to which the gasket  420  protrudes within the mixing tube  124  is decided optimally, based on system requirements. In some embodiments, a second gasket  422  may also be provided in contact with the gasket  420 . The gaskets  420 ,  422  may be together configured to adjust the depth of protrusion of the reductant injector tip  416  into the mixing tube  124 . 
     Referring to  FIG. 4 , the contoured region  410  includes a first lobe  424  and a second lobe  426 . The first and second lobes  424 ,  426  are provided on either sides of the cut out portion  412 . The first and second lobes  424 ,  426  are connected at the throat portion  414  of the contoured region  410 . The first lobe  424  is positioned at a location upstream of the cut out portion  412  with respect to the exhaust gas flow direction “F” (see  FIG. 5 ). More particularly, the first lobe  424  is positioned at the upstream end  418  of the contoured region  410  with respect to the exhaust gas flow direction “F”. Whereas, the second lobe  426  is positioned downstream of the cut out portion  412  with respect to the exhaust gas flow direction “F” (see  FIG. 5 ). More particularly, the second lobe  426  is positioned at the downstream end  417  of the contoured region  410  with respect to the exhaust gas flow direction “F”. 
     Referring to  FIG. 4 , the first lobe  424  of the contoured region  410 . The width “W 1 ” is measured along an axis X-X′ of the reductant injector mount  200 , wherein the axis X-X′ is perpendicular to the axis A-A′. Further, the second lobe  426  of the contoured region  410  has a width “W 2 ”. The width “W 2 ” is measured along the axis X-X′ of the reductant injector mount  200 . A ratio “R 1 ” of the width “W 1 ” to the diameter “D” of the cut out portion  412  and a ratio “R 2 ” of the width “W 2 ” to the diameter “D” of the cut out portion  412  are decided such that the velocity of the exhaust gas flow is increased through the contoured region  410  and recirculation of the exhaust gas flow therethrough is reduced. In one embodiment, the ratio “R 1 ” of the width “W 1 ” of the first lobe  424  to the diameter “D” of the cut out portion  412  is approximately from 0.75 to 5. In some embodiments, the ratio “R 1 ” is approximately from 0.75 to 2.5 or 2.5 to 5. In one example, the ratio “R 1 ” may be approximately equal to 2.5. 
     In one embodiment of the present disclosure, the width “W 1 ” of the first lobe  424  may be equal to the width “W 2 ” of the second lobe  426 . Therefore, the ratio “R 1 ” may be equal to the ratio “R 2 ”. Accordingly, the ratio “R 2 ” of the width “W 2 ” of the second lobe  426  to the diameter “D” of the cut out portion  412  is approximately from 0.75 to 5. In some embodiments, the ratio “R 2 ” is approximately from 0.75 to 2.5 or 2.5 to 5. In one example, the ratio “R 2 ” may be approximately equal to 2.5. Alternatively, the width “W 1 ” of the first lobe  424  may be different than the width “W 2 ” of the second lobe  426 . In such an example, the ratio “R 1 ” may be different than the ratio “R 2 ”. 
     When the reductant injector mount  200  is mounted on the mixing tube  124 , a curved surface of the contoured region  410  of the reductant injector mount  200  faces the exhaust gas flow. The curvature of the contoured region  410  varies along a cross section of the reductant injector mount  200 . Referring to  FIG. 5 , the first and second lobes  424 ,  426  are provided at an angle with respect to the mounting region  402 . An angle of incidence “α 1 ”, “α 2 ” of the first and second lobes  424 ,  426  respectively are decided such that the exhaust gas flow adapts a streamlined flow in the contoured region  410 . The angle of incidence “α 1 ” hereinafter is interchangeably referred to as receiving angle “α 1 ”, and is defined at the upstream end  418  of the contoured region  410  of the reductant injector mount  200 , with respect to the exhaust gas flow direction “F”. 
     More particularly, the receiving angle “α 1 ” is formed by an upstream end  436  of the first lobe  424  with respect to the mounting region  402  of the reductant injector mount  200 . The exhaust gas flow is received on the contoured region  410  of the reductant injector mount  200  at the receiving angle “α 1 ”. In one embodiment, the angle of incidence “α 1 ” of the contoured region  410  at the first lobe  424  is approximately from 3° to 45°. In one example, the angle of incidence “α 1 ” may be approximately 6°. Further, the angle of incidence “α 2 ” of the contoured region  410  at the second lobe  426  is approximately from 10° to 45°. For example, the angle of incidence “α 2 ” may be approximately 17°. 
     Referring to  FIG. 6 , the reductant injector mount  200  has a thickness “D 1 ” at a downstream end  432  of the first lobe  424 . The thickness “D 1 ” may be measured from a distance “A” from an axis Y-Y′ of the cut out portion  412 . Further, the reductant injector mount  200  has a thickness “D 2 ” at a downstream end  434  of the second lobe  426 . The depth “D 2 ” may be measured from a distance “B” from the axis Y-Y′ of the cut out portion  412 . It should be noted that the distance “A” referred to herein is equal to the distance “B”. Further, a ratio “R 3 ” of the thickness “D 1 ” to the thickness “D 2 ” is approximately from 0.4 to 0.9. In some embodiments, the ratio “R 3 ” is approximately from 0.4 to 0.6 or 0.6 to 0.9. In one example, the ratio “R 3 ” may be approximately equal to 0.7. 
     Referring now to  FIG. 7 , a perspective view of an alternate embodiment of the reductant injector mount  700  is shown. In this embodiment, a circumference of the cut out portion  702  of the contoured region  704  disposed on the mounting region  710  is defined by a tapered region  708 . The tapered region  708  tapers along a thickness “T” of the reductant injector mount  700  towards the outer surface  706  of the reductant injector mount  700 . More particularly, a diameter of the cut out portion  702  decreases along the thickness “T” towards the outer surface  706  of the reductant injector mount  700 , such that a diameter “D” of the cut out portion  702  at the contoured region  704  is greater than a diameter “d” at the outer surface  706  of the reductant injector mount  700 . It should be noted that the design and shape of the contoured region  410 ,  704  and thus the reductant injector mount  200 ,  700  is not limited to the exemplary illustrations in  FIGS. 4-7  and may vary therefrom. 
       FIG. 8  illustrates another reductant injector mount  800 , according to one embodiment of the present disclosure. As illustrated, the contoured region  802  is formed in the mounting region  810  of the reductant injector mount  800  may have an approximately oblong shape, with curved sections  814 ,  816  provided at either ends along the axis Z-Z′. In this embodiment, a width “W 3 ” of the contoured region  802  is uniform along the axis Z-Z′ of the reductant injector mount  800 . 
     As discussed earlier, based on system requirements, the reductant injector mounts  202  may be positioned angularly on the mixing tube  124  with respect to the exhaust gas flow direction “F” (see  FIG. 3 ). Referring to  FIG. 9 , accordingly the contoured region  902  is formed in the mounting region  904  of such reductant injector mounts  202  are oriented so that the contoured region  902  is aligned with respect to the exhaust gas flow direction “F”, when the reductant injector mount  202  is fitted onto the mixing tube  124 . An axis F-F′ defined by the contoured region  902  is parallel to the exhaust gas flow direction “F”. More particularly, the axis F-F′ of the contoured region  902  is angled with respect to the axis Z-Z′, so that the contoured region  902  is aligned with the exhaust gas flow direction “F”. It should be noted that the design of the contoured region  902  shown in  FIG. 9  is exemplary, and may include any other design, such as that explained in  FIGS. 4-7 , without limiting the scope of the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     Flow field around an injection location of the reductant injector mounted on the mixing tube may have unfavorable recirculating and/or low velocity patterns of the exhaust gas flow. This may create/increase formation of urea deposits that may be present in the reductant. Such urea deposition can prevent/hinder the reductant spray pattern/interaction with the exhaust gas flow and further cause deposition issues and reduce NOx conversion in the aftertreatment system. 
       FIG. 10  is a flowchart for a method  1000  for controlling exhaust gas flow in the conduit  123 . At step  1002 , the reductant injector  128  is received through the mounting region  402 ,  710 ,  810 ,  904  of the reductant injector mount  200 ,  202 ,  700 ,  800 . At step  1004 , the exhaust gas flows over the contoured region  410 ,  704 ,  802 ,  902  of the reductant injector mount  200 ,  202 ,  700 ,  800 . At step  1006 , based on the flow, the velocity of the exhaust gas flow increases through the contoured region  410 ,  704 ,  802 ,  902 . Further, the exhaust gas flow is received at the receiving angle “α 1 ”. 
     At step  1008 , based on the flow, the recirculation of the exhaust gas flow flowing through the contoured region  410 ,  704 ,  802 ,  902  is reduced. The exhaust gas flow is then discharged towards the SCR module  138  provided downstream of the conduit  123 . The flow field provided by the contoured region  410 ,  704 ,  802 ,  902  of the reductant injector mount  200 ,  202 ,  700 ,  800  has reduced or no recirculation around the reductant injector tip  416  and also increases the velocity near the injection location. 
     Accordingly, the deposit formation of the reductant around the reductant injector tip  416  may reduce or be eliminated because of reduced recirculation and increased velocity of the exhaust gas flow through the reductant injector mount  200 ,  202 ,  700 ,  800 . Further, the reductant may uniformly mix with the exhaust gas flow and an improved NOx conversion may take place in the aftertreatment system  114 . Also, servicing and maintenance associated with removal of the reductant deposits close to the reductant injector  128  may be reduced, thereby decreasing cost associated with servicing and maintenance cost of the aftertreatment system  114 . 
     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.