Crown inlet baffles for high efficiency mixers

Abstract

A mixer assembly for a vehicle exhaust system includes a mixer housing defining an inner cavity, wherein the mixer housing includes an upstream end and a downstream end, and a reactor positioned within the inner cavity, the upstream end being configured to receive exhaust gas. The reactor has a reactor inlet and a reactor outlet, the reactor inlet being configured to receive an injected fluid, and the reactor outlet directing a mixture of the exhaust gas and the injected fluid into the inner cavity. An inlet baffle is mounted to the upstream end of the mixer housing. The inlet baffle includes at least one opening and a plurality of bypass openings, at least one opening directing exhaust gas into at least one exhaust gas inlet of the reactor, and the plurality of bypass openings directing exhaust gas to bypass the reactor. The inlet baffle includes a crown portion that curves away from the reactor to provide an increased open area within the inner cavity between the inlet baffle and the reactor.

Description

Technical Field

[0001] The present disclosure is generally directed to an exemplary compact mixer configuration that includes a crown-shaped inlet baffle to maintain high mixing performance with increased durability. Background Art

[0002] The exhaust system includes a catalyst component to reduce emissions. The exhaust system includes an injection system that injects diesel exhaust fluid (DEF), or a reductant such as a solution of urea and water, upstream of a selective catalytic reduction (SCR) catalyst that is used to reduce NOx emissions. The injection system includes a meter that injects the fluid into the exhaust gas flow. A mixer is positioned upstream of the SCR catalyst to mix the engine exhaust gas with the injected fluid. Constructing multiple exhaust system components within the available packaging space is a challenge. A compact mixer configuration has a short overall length to achieve more efficient packaging, but needs to maintain high mixing performance while also meeting durability requirements to accommodate vehicle and road vibrations. Summary of the invention

[0003] A mixer assembly according to an exemplary aspect of the present disclosure mainly includes: a mixer housing defining an inner cavity, wherein the mixer housing includes an upstream end and a downstream end, and a reactor positioned in the inner cavity, and the upstream end is configured to receive exhaust gas. The reactor has a reactor inlet and a reactor outlet, the reactor inlet is configured to receive an injected fluid, and the reactor outlet introduces a mixture of exhaust gas and injected fluid into the inner cavity. An inlet baffle is mounted to the upstream end of the mixer housing. The inlet baffle includes at least one opening and a plurality of bypass openings, at least one opening introduces exhaust gas into at least one exhaust gas inlet of the reactor, and the plurality of bypass openings guide the exhaust gas to bypass the reactor (bypass the reactor). The inlet baffle includes a crown portion that bends away from the reactor to provide an increased open area in the inner cavity between the inlet baffle and the reactor.

[0004] In a further non-limiting embodiment of the foregoing assembly, the mixer housing defines a mixer central axis, wherein the at least one opening is positioned on one side of the central axis and the crown portion is positioned on an opposite side of the central axis.

[0005] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet baffle includes a flange formed around a periphery of the inlet baffle, the flange including an attachment interface with the mixer housing, and wherein the crown portion includes a curved surface that curves from a base of the flange at one peripheral location on the inlet baffle to a base of the flange at an opposite peripheral location on the inlet baffle.

[0006] In a further non-limiting embodiment of any of the foregoing assemblies, including a relief formed in a portion of the crown portion, the relief protruding outwardly and away from an upstream surface of the crown portion to further increase the open area within the inner cavity between the inlet baffle and the reactor at the relief.

[0007] In a further non-limiting embodiment of any of the foregoing assemblies, the mixer housing defines a mixer central axis, and wherein the relief comprises a C-shape defined by a radially outward edge and a radially inward edge connected by opposing side edges.

[0008] In a further non-limiting embodiment of any of the foregoing assemblies, at least some of the plurality of bypass openings are formed in the relief.

[0009] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet baffle comprises: a first portion comprising at least one opening; a second portion comprising a plurality of bypass openings; and a third portion comprising at least one sensor mounting area, and wherein the third portion separates the first portion and the second portion from each other, and wherein the crown portion is formed within the second portion.

[0010] In a further non-limiting embodiment of any of the foregoing assemblies, the sensor mounting area includes at least a first indentation and a second indentation, the first indentation and the second indentation each being configured to receive a sensor, wherein the indentations extend in a downstream direction.

[0011] In a further non-limiting embodiment of any of the foregoing assemblies, the first and second indentations are interconnected by a rib.

[0012] In a further non-limiting embodiment of any of the foregoing assemblies, a relief is formed in the crown portion, the relief protruding outwardly and away from an upstream surface of the crown portion to further increase an open area within the inner cavity between the inlet baffle and the reactor at the relief.

[0013] In a further non-limiting embodiment of any of the foregoing assemblies, the mixer housing defines a mixer central axis, and wherein the inlet baffle includes a solid surface portion without the plurality of bypass openings, and wherein the solid surface portion is positioned radially between the relief and the first and second indentations.

[0014] In a further non-limiting embodiment of any of the foregoing assemblies, the relief comprises a C-shape that extends partially around the mixer central axis.

[0015] In a further non-limiting embodiment of any of the foregoing assemblies, an outlet baffle is mounted to a downstream end of the mixer housing, the outlet baffle comprising a plurality of mixer outlet openings.

[0016] According to another exemplary aspect of the present disclosure, an assembly generally includes: a mixer housing having a mixer central axis and defining an inner cavity, wherein the mixer housing includes an upstream end and a downstream end, the upstream end being configured to receive exhaust gas, and wherein the mixer housing includes a metering opening configured to receive a metering device for injecting fluid. A reactor is positioned within the inner cavity. The reactor has: a reactor inlet aligned with the metering opening for receiving injected fluid; at least one exhaust gas inlet for introducing exhaust gas into the reactor; and a reactor outlet for introducing a mixture of exhaust gas and fluid into the inner cavity; an inlet baffle mounted to the upstream end of the mixer housing, wherein the inlet baffle includes at least one opening and a plurality of bypass openings, the at least one opening introducing exhaust gas into the at least one exhaust gas inlet of the reactor, and the plurality of bypass openings directing exhaust gas to bypass the inlet of the reactor. The inlet baffle includes a crown portion that curves away from the reactor to provide an increased open area within the inner cavity between the inlet baffle and the reactor. An outlet baffle mounted to the downstream end of the mixer housing, the outlet baffle including a plurality of mixer outlet openings.

[0017] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet baffle comprises: a first portion comprising at least one opening; a second portion comprising a plurality of bypass openings; and a third portion comprising at least one sensor mounting area, and wherein the third portion separates the first portion and the second portion from each other, and wherein the crown portion is formed within the second portion.

[0018] In a further non-limiting embodiment of any of the foregoing assemblies, the sensor mounting area includes at least a first indentation and a second indentation, the first indentation and the second indentation each configured to receive a sensor, wherein the indentations extend in a downstream direction.

[0019] In a further non-limiting embodiment of any of the foregoing assemblies, the first and second indentations are interconnected by a rib, and wherein the rib includes an additional indentation.

[0020] In a further non-limiting embodiment of any of the foregoing assemblies, includes a relief formed in the crown portion, the relief protruding outwardly and away from the upstream surface of the crown portion to further increase the open area within the inner cavity between the inlet baffle and the reactor at the relief.

[0021] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet baffle includes a solid surface portion devoid of the plurality of bypass openings, and wherein the solid surface portion is positioned radially between the relief and the first and second indentations.

[0022] In a further non-limiting embodiment of any of the foregoing assemblies, the relief comprises a C-shape defined by a radially outward edge and a radially inward edge connected by opposing side edges.

[0023] The embodiments, examples and alternatives of the preceding paragraphs, the claims or the following description and drawings, including their various aspects or corresponding individual features, may be adopted independently or in any combination. Features described in conjunction with one embodiment are applicable to all embodiments, unless these features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 An example of an exhaust system according to the present disclosure is schematically shown.

[0025] Figure 2 yes Figure 1 A perspective view of a mixer with an inlet reactor and an inlet baffle used in an exhaust system of FIG.

[0026] Figure 3 yes Figure 2 Schematic diagram of the reactor inlet is shown.

[0027] Figure 4 is used for Figure 2 A cross-sectional view of the inlet baffle of the mixer is shown.

[0028] Figure 5A yes Figure 2 An end view of the upstream side of the inlet baffle is shown.

[0029] Figure 5B yes Figure 2 An end view of the downstream side of the inlet baffle is shown.

[0030] Fig. 6A yes Figure 5A-5B A side view of the inlet baffle is shown.

[0031] Figure 6B yes Figure 5A-5B Opposite side views of the inlet baffle are shown.

[0032] Figure 6C yes Figure 5A-5B A perspective view of the inlet baffle is shown. DETAILED DESCRIPTION

[0033] The present disclosure details an exemplary mixer that achieves high mixing performance in a compact mixer configuration by redirecting a bypass flow that has preheated a reactor mixing chamber using a flow deflector to mix it with the flow exiting the mixing chamber before reaching an exhaust aftertreatment catalyst.

[0034] Figure 1 A vehicle exhaust system 10 is shown that directs hot exhaust gases generated by an engine 12 through various exhaust components to reduce emissions and control noise as is known. In one example configuration, at least one pipe 14 directs engine exhaust gases exiting the exhaust manifold of the engine 12 to one or more exhaust gas aftertreatment components. In one example, the exhaust aftertreatment components include a diesel oxidation catalyst (DOC) 16, and an optional diesel particulate filter (DPF) 18, which are used to remove pollutants from the exhaust gas as is known.

[0035] Downstream of the DOC 16 and optional DPF 18 is a selective catalytic reduction (SCR) catalyst 22 having an inlet 24 and an outlet 26. Optionally, the component 22 may include a catalyst configured to perform both a selective catalytic reduction function and a particulate filter function. The outlet 26 of the SCR 22 communicates the exhaust gas to downstream exhaust components 28, which ultimately exit to the atmosphere via the tailpipe 20. The various downstream exhaust components 28 may include one or more of the following: pipes, filters, valves, catalysts, mufflers, etc. These exhaust system components may be installed in a variety of different configurations and combinations depending on the vehicle application and available packaging space.

[0036] In one example, the mixer 30 is positioned downstream of the outlet of the DOC 16 or DPF 18 and upstream of the inlet 24 of the SCR 22. For example, the DOC / DPF and SCR may be connected in series or in parallel. The mixer 30 is used to facilitate mixing of the exhaust gases.

[0037] The injection system 32 is used to inject a reductant, such as diesel exhaust fluid (DEF), into the exhaust gas flow upstream of the SCR catalyst 22 so that the mixer 30 can thoroughly mix the DEF and the exhaust gas together. The injection system 32 includes a fluid supply tank 34, a meter 36, and a controller 38 that controls the injection of the fluid as is known. In one example, the meter 36 injects the DEF into the mixer 30, such as Figure 1 shown.

[0038] The control system includes a controller 38, which controls the injection of DEF based on one or more of exhaust gas temperature, back pressure, time, etc. The controller 38 can be a dedicated electronic control unit or an electronic control unit associated with a vehicle system control unit or a subsystem control unit. The controller 38 can include a processor, a memory, and one or more input and / or output (I / O) device interfaces, which are communicatively connected via a local interface. The controller 38 can be a hardware device for executing software, particularly executing software stored in the memory.

[0039] The mixer 30 is used to generate a swirling or rotating motion of the exhaust gas. The mixer 30 has an inlet end 40 configured to receive the engine exhaust gas and an outlet end 42 configured to direct the mixture of the swirling engine exhaust gas and the products converted by the injected fluid to the SCR catalyst 22. Figure 2 An example of a mixer 30 is shown. The mixer 30 includes an inlet baffle 44 located at the inlet end 40. An outlet baffle 46 ( Figure 1 ) is associated with the outlet port 42. Figure 2 As shown, the inlet baffle 44 includes at least one large inlet opening 48 that receives a majority of the exhaust gas and directs the exhaust gas to an exhaust gas inlet 50 that enters an inlet reactor 52. The inlet baffle 44 also includes a plurality of perforations, slots, or additional inlet openings 54 that allow the remaining exhaust gas to bypass the inlet reactor 52 to promote optimal homogenization of the exhaust gas and reduce back pressure.

[0040] The inlet baffle 44 and the outlet baffle 46 are fixed to a mixer housing 56, which defines a mixer central axis A and provides an inner cavity 58 ( Figure 1 ). The inlet reactor 52 is located within the inner cavity 58. In one example, the baffle comprises a stamped sheet metal part. For packaging considerations, in order to make the compact mixer as short as possible, the inlet baffle 44 is placed as close to the reactor 52 as possible. The exhaust gas and the injected fluid spray injected into the inlet reactor 52 via the meter 36 are mixed within the inlet reactor 52 and exit into the inner cavity 58 before exiting the mixer 30 to mix with the bypassed exhaust gas.

[0041] In one example, the inlet reactor 52 is used to facilitate mounting the meter 36 relative to the mixer housing 56. Figure 3 As shown, the inlet reactor 52 includes a meter mounting portion 60 and a vortex chamber 62 extending into the inner cavity 58. The meter mounting portion 60 is formed in a meter opening 64 ( Figure 2 ) is mounted to the mixer housing 56. The meter mounting portion 60 is configured to support the meter 36, which injects fluid into the vortex chamber 62 via a reactor inlet 70 aligned with the meter opening 64.

[0042] In one example, the vortex chamber 62 has a first end 66 at the meter opening 64 and a second end 68 at the outlet. In one example, the vortex chamber 62 includes a plurality of flow elements 74 attached to each other to form an open interior region within the vortex chamber 62.

[0043] In one example, the inlet reactor 52 has a fluid inlet 70 and one or more exhaust gas inlets 50 ( Figure 3 ). The fluid inlet 70 is aligned with the meter opening 64 and defines an injection axis I that is transverse to the mixer center axis A. In one example, the injection axis I is substantially perpendicular to the mixer center axis A. The large inlet opening 48 of the inlet baffle 44 directs the exhaust gas into the exhaust gas inlet 50. A plurality of bypass openings 54 direct the exhaust gas to bypass the reactor 52 (bypass the reactor 52 and do not enter the reactor 52).

[0044] In one example, the inlet reactor 52 extends along the injection axis I from a first end 66 at a fluid inlet 70 to a second end 68 including a reactor outlet 76. In one example, the bowl portion 72 includes an end cap that encloses the second end 68 of the inlet reactor 52. The reactor outlet 76 directs the mixture of exhaust gas and the injected fluid into the inner cavity 58. Then, as Figure 1 As shown, the mixture exits the outlet baffle 46 via a plurality of outlet baffle openings 78 .

[0045] In one example, the reactor outlet 76 includes a plurality of openings 84 that are circumferentially spaced apart from one another about the injection axis I. The reactor 52 extends along the injection axis I from the first end 66 to the second end 68 including the bowl portion 72. This provides an open mixing chamber or vortex chamber 62 within the reactor 52 between the first end 66 and the second end 68.

[0046] In one example, the bowl portion 72 includes a solid base surface 86, e.g., a surface without openings, that faces the inlet 70 and includes a peripheral wall 88 that extends around the perimeter of the solid base surface 86 and toward the fluid inlet 70. In one example, the peripheral wall 88 includes a plurality of reactor outlet openings 84 through which the mixture of fluid and exhaust gas exits the inlet reactor 52.

[0047] In one example, the inlet reactor 52 has a smaller cross-section at the first end 66 than at the second end 68 to form a conical shape. In one example, the meter mounting portion 60 at the first end 66 includes a central boss 90 with the fluid inlet 70 .

[0048] like Figure 4 As shown, the inlet baffle 44 includes a crown portion 92 that curves away from the reactor 52 to provide an increased open area 94 within the interior cavity 58 between the inlet baffle 44 and the reactor 52. In one example, as shown in FIG. Figure 2As shown, the large inlet opening 48 is located on one side of the central axis A, while the crown portion 92 is located on the opposite side of the central axis A. Thus, the crown portion 92 does not extend across the entire inlet baffle 44 , but rather only extends across a portion of the inlet baffle 44 .

[0049] In one example, the inlet baffle 44 includes a flange 96 formed around the perimeter of the inlet baffle 44. The flange 96 includes a flange 96 that is secured to the mixer housing 56 ( Figure 4 ) attachment interface. In one example, the flange extends away from the inlet baffle in the upstream direction. The crown portion 92 includes a curved surface S ( Fig. 6A ), the curved surface S curves from the base 98 of the flange 96 at one peripheral location on the inlet baffle 44 to the base 98 of the flange 96 at an opposite peripheral location on the inlet baffle 44. The curved surface S forms an increased open area 94 within the interior cavity 58 between the downstream surface 100 of the inlet baffle 44 and the outer surface 102 of the reactor 52.

[0050] In one example, the inlet baffle 44 includes a relief 104 formed within a portion of the crown portion 92. In other words, the relief 104 does not extend across the entire crown portion 92, but rather only covers discrete areas of the crown portion 92. In one example, the relief 104 protrudes outwardly and away from an upstream surface 106 of the crown portion 92 to further increase the open area 94 within the inner cavity 58 between the inlet baffle 44 and the reactor 52 at the relief 104.

[0051] exist Figure 5A-5B In one example best shown in FIG. 1 , the relief 104 includes a C-shape defined by a radially outward edge 108 and a radially inward edge 110 connected by opposing side edges 112. In one example, the relief 104 extends only partially around the mixer central axis A. In one example, at least some of the plurality of bypass openings 54 are formed in the relief 104. The relief 104 and the crown portion 92 provide the inlet baffle 44 with greater durability to accommodate road and vehicle vibrations.

[0052] In one example, the inlet baffle 44 includes a first portion 114 including a large opening 48, a second portion 116 including a bypass opening 54, and a third portion 118 including at least one sensor mounting area 120. The third portion 118 separates the first portion 114 and the second portion 116 from each other. In one example, the crown portion 92 is formed within the second portion 116. The advantage of this location is that the open area 94 increases at the location of the larger cross-section of the reactor 52. As described above, the inlet reactor 52 has a conical shape, and its cross-section becomes larger and larger in the direction extending toward the reactor outlet 76. By forming the crown portion 92 at a location overlapping the outlet opening 84 at the larger cross-sectional portion of the reactor 52, the inlet baffle 44 can be placed as close to the reactor as possible to keep the overall length of the mixer as short as possible.

[0053] In one example, the sensor mounting area 120 includes at least first and second indentations 122, each configured to receive a sensor. In one example, the indentation 122 extends in a downstream direction. To further improve durability, the inlet baffle 44 may also include one or more ribs 124. In one example, the first and second indentations 122 are interconnected using the ribs 124. In one example, the ribs 124 include additional indentations 126, which are also connected to the sensor indentation 122. In one example, as shown in FIG. Figure 5B As shown, the rib indentation 126 is intended to be less extensive than the sensor indentation.

[0054] Figure 6B is a cross-sectional view through one of the indentations 122. Fig. 6A and 6C As shown in FIG. 1 , the crown portion 92 is located on one side of the indentation 122 and the large inlet opening 48 is located on the opposite side of the indentation.

[0055] In one example, the inlet baffle 44 includes a solid surface portion 130 without the plurality of bypass openings 54. Figure 5A-5B and Figure 6C As shown, the solid surface portion 130 is positioned radially between the relief 104 and the first and second indentations 122 .

[0056] The primary advantage of strategically positioning the reinforcing crown portion 92 and the embossment 104 on the inlet baffle 44 is that the flow rate out of the reactor 52 from the outlet opening 84 closest to the inlet baffle 44 is increased, resulting in a more uniform ammonia mixture in the mixer 30 with the lowest back pressure in the shortest overall mixer length. Initial computational fluid dynamics (CFD) results indicate that the flow rate from the disclosed inlet baffle 44 can be increased by approximately 25% compared to a conventional flat baffle. In addition, the crown portion 92 and / or the embossment 104 strengthen the inlet baffle 44 by increasing the natural frequency, which reduces vibration.

[0057] The present disclosure forms the crown 92 and / or relief 104 in a specific location in the inlet baffle 44 and in a desired direction to increase the area for flow exiting the reactor 52 while keeping the inlet baffle 44 as close to the reactor 52 as possible. The crown and / or relief 104 are attached to the inlet baffle 44 in a direction away from the reactor 52 and in a location on the inlet baffle that overlaps with the increased cross-sectional portion of the reactor 52 to allow for increased flow exiting the reactor 52 through the apertures 84 located closest to the inlet baffle 44. This also allows the inlet baffle 44 to be placed very close to the reactor 52 to keep the overall length of the mixer 30 as short and compact as possible.

[0058] Although specific component relationships are illustrated in the drawings of the present disclosure, these illustrations are not intended to limit the present disclosure. In other words, the placement and orientation of the various components shown can vary within the scope of the present disclosure. In addition, the various drawings attached to the present disclosure are not necessarily drawn to scale, but some features may be exaggerated or minimized to show certain details of specific components.

[0059] The above description is illustrative rather than restrictive in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art without departing from the essence of the present disclosure. Therefore, the scope of legal protection afforded to the present disclosure can only be limited by studying the following claims.

Claims

1. A mixer assembly for a vehicle exhaust system, comprising: a mixer housing defining an internal cavity, wherein the mixer housing includes an upstream end and a downstream end, the upstream end being configured to receive exhaust gas; a reactor positioned within the inner cavity, the reactor having a reactor inlet and a reactor outlet, the reactor outlet including a plurality of outlet openings, the reactor inlet being configured to receive an injected fluid, the reactor outlet directing a mixture of exhaust gas and the injected fluid into the inner cavity; as well as an inlet baffle mounted to the upstream end of the mixer housing, wherein the inlet baffle includes at least one opening directing exhaust gas into at least one exhaust gas inlet of the reactor and a plurality of bypass openings directing the exhaust gas to bypass entry of the reactor, wherein the inlet baffle includes a crown portion that curves away from the reactor to provide an increased open area within the interior cavity between the inlet baffle and the reactor, wherein the inlet baffle includes a flange formed around a periphery of the inlet baffle, the flange including an attachment interface with the mixer housing, and wherein the crown portion includes a curved surface that curves from a base of the flange at one peripheral location on the inlet baffle to a base of the flange at an opposite peripheral location on the inlet baffle.

2. The mixer assembly according to claim 1, characterized in that The mixer housing defines a mixer central axis, and wherein the at least one opening is positioned on one side of the mixer central axis and the crown portion is positioned on an opposite side of the mixer central axis, and wherein the plurality of outlet openings are circumferentially spaced from one another around an injection axis, the injection axis being non-parallel to the mixer central axis.

3. A mixer assembly for a vehicle exhaust system, comprising: a mixer housing defining an internal cavity, wherein the mixer housing includes an upstream end and a downstream end, the upstream end being configured to receive exhaust gas; a reactor positioned within the inner cavity, the reactor having a reactor inlet configured to receive an injected fluid and a reactor outlet directing a mixture of exhaust gas and the injected fluid into the inner cavity; an inlet baffle mounted to the upstream end of the mixer housing, wherein the inlet baffle includes at least one opening directing exhaust gas into at least one exhaust gas inlet of the reactor and a plurality of bypass openings directing the exhaust gas to bypass entry of the reactor, and wherein the inlet baffle includes a crown portion that curves away from the reactor to provide an increased open area within the interior cavity between the inlet baffle and the reactor, and A relief is formed in a portion of the crown portion, the relief protruding outward and away from an upstream surface of the crown portion to further increase the open area in the inner cavity between the inlet baffle and the reactor at the relief.

4. The mixer assembly according to claim 3, characterized in that The mixer housing defines a mixer central axis, and wherein the relief comprises a C-shape defined by a radially outward edge and a radially inward edge connected by opposing side edges.

5. The mixer assembly according to claim 3, characterized in that At least some of the plurality of bypass openings are formed in the relief.

6. A mixer assembly for a vehicle exhaust system, comprising: a mixer housing defining an internal cavity, wherein the mixer housing includes an upstream end and a downstream end, the upstream end being configured to receive exhaust gas; a reactor positioned within the inner cavity, the reactor having a reactor inlet configured to receive an injected fluid and a reactor outlet directing a mixture of exhaust gas and the injected fluid into the inner cavity; as well as an inlet baffle mounted to the upstream end of the mixer housing, wherein the inlet baffle includes at least one opening directing exhaust gas into at least one exhaust gas inlet of the reactor and a plurality of bypass openings directing the exhaust gas to bypass entry of the reactor, and wherein the inlet baffle includes a crown portion that curves away from the reactor to provide an increased open area within the interior cavity between the inlet baffle and the reactor, wherein the inlet baffle comprises: a first portion comprising the at least one opening; a second portion comprising the plurality of bypass openings; and a third portion comprising at least one sensor mounting area, and wherein the third portion separates the first portion and the second portion from each other, and wherein the crown portion is formed within the second portion.

7. The mixer assembly according to claim 6, characterized in that The sensor mounting area includes at least a first indentation and a second indentation, each configured to receive a sensor, wherein the indentations extend in a downstream direction.

8. The mixer assembly according to claim 7, characterized in that The first dimples and the second dimples are connected to each other by ribs.

9. The mixer assembly according to claim 7, characterized in that A relief is formed in the crown portion, the relief protruding outward and away from the upstream surface of the crown portion to further increase the open area in the inner cavity between the inlet baffle and the reactor at the relief.

10. The mixer assembly according to claim 9, characterized in that The mixer housing defines a mixer central axis, and wherein the inlet baffle includes a solid surface portion devoid of the plurality of bypass openings, and wherein the solid surface portion is positioned radially between the relief and the first and second indentations.

11. The mixer assembly according to claim 9, characterized in that The relief comprises a C-shape extending partially around a mixer central axis of the mixer.

12. The mixer assembly of claim 6 including an outlet baffle mounted to the downstream end of the mixer housing, the outlet baffle including a plurality of mixer outlet openings.

13. A mixer assembly for a vehicle exhaust system, comprising: a mixer housing having a mixer central axis and defining an internal cavity, wherein the mixer housing includes an upstream end and a downstream end, the upstream end being configured to receive exhaust gas, and wherein the mixer housing includes a meter opening configured to receive a meter, the meter injecting a fluid; a reactor positioned within the inner cavity, the reactor having: a reactor inlet aligned with the meter opening to receive an injected fluid; at least one exhaust gas inlet for introducing exhaust gas into the reactor; and a reactor outlet for introducing a mixture of exhaust gas and fluid into the inner cavity; an inlet baffle mounted to the upstream end of the mixer housing, wherein the inlet baffle includes at least one opening directing exhaust gas into the at least one exhaust gas inlet of the reactor and a plurality of bypass openings directing the exhaust gas to bypass entry of the reactor, wherein the inlet baffle includes a crown portion curving away from the reactor for providing an increased open area within the interior cavity between the inlet baffle and the reactor, the inlet baffle including: a first portion including the at least one opening, a second portion including the plurality of bypass openings, and a third portion including at least one sensor mounting area, and wherein the third portion separates the first portion and the second portion from each other, and wherein the crown portion is formed within the second portion; as well as An outlet baffle is mounted to the downstream end of the mixer housing, the outlet baffle including a plurality of mixer outlet openings.

14. The mixer assembly according to claim 13, characterized in that The sensor mounting area includes at least a first indentation and a second indentation, each configured to receive a sensor, wherein the indentations extend in a downstream direction.

15. The mixer assembly according to claim 14, characterized in that The first dimple and the second dimple are connected to each other by a rib, and wherein the rib comprises an additional dimple.

16. The mixer assembly according to claim 14, characterized in that A relief is formed in the crown portion, the relief protruding outward and away from the upstream surface of the crown portion to further increase the open area in the inner cavity between the inlet baffle and the reactor at the relief.

17. The mixer assembly according to claim 16, characterized in that The inlet baffle includes a solid surface portion devoid of the plurality of bypass openings, and wherein the solid surface portion is positioned radially between the relief and the first and second indentations.

18. The mixer assembly according to claim 17, characterized in that The relief comprises a C-shape defined by a radially outward edge and a radially inward edge connected by opposing side edges.

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