Inlet flow section of high efficiency mixer

Abstract

A mixer assembly for a vehicle exhaust system includes a mixer housing defining an inner cavity and including an inlet reactor located within the inner cavity. The inlet reactor has a fluid inlet, a first exhaust gas inlet, and a second exhaust gas inlet. An inlet baffle is mounted to an upstream end of the mixer housing. The inlet baffle includes a first opening for directing exhaust gas into the first exhaust gas inlet, a bucket for directing exhaust gas into the second exhaust gas inlet, and a plurality of bypass openings for directing exhaust gas around entry into the inlet reactor.

Description

Technical Field

[0001] The present invention relates to an inlet flow section of a high efficiency mixer for an exhaust system of a vehicle. 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 for reducing NOx emissions. The injection system includes a metering device that injects the fluid into the exhaust gas flow. A mixer is positioned upstream of the SCR catalyst for mixing the engine exhaust gas with the injected fluid. It is a challenge to construct multiple exhaust system components within the available packaging space. A compact mixer configuration enables more efficient packaging, but it is necessary to maintain high mixing performance while limiting the generation of back pressure. Summary of the invention

[0003] According to an exemplary aspect of the present disclosure, a mixer assembly mainly includes a mixer housing, which defines an inner cavity and an inlet reactor positioned in the inner cavity. The inlet reactor has a fluid inlet, a first exhaust gas inlet, and a second exhaust gas inlet. An inlet baffle is mounted to the upstream end of the mixer housing. The inlet baffle includes a first opening for guiding the exhaust gas into the first exhaust gas inlet, a bucket-shaped portion for guiding the exhaust gas into the second exhaust gas inlet, and a plurality of bypass openings for guiding the exhaust gas to bypass and enter the inlet reactor (not enter the inlet reactor).

[0004] In a further non-limiting embodiment of the foregoing assembly, the inlet baffle has a baffle center and is divided into a plurality of segments spaced circumferentially about the baffle center, and wherein the first opening is located in a first segment of the plurality of segments, the scoop is located in a second segment of the plurality of segments separate from the first segment, and the plurality of bypass openings are located in a third segment of the plurality of segments separate from the first segment and the second segment.

[0005] In a further non-limiting embodiment of any of the foregoing assemblies, the third segment is located on an opposite side of the center of the baffle from the first and second segments.

[0006] In a further non-limiting embodiment of any of the foregoing assemblies, the plurality of segments include four quadrants, wherein the first segment includes the first quadrant, the second segment includes the second quadrant, and the third segment extends across a third and a fourth quadrant of the four quadrants.

[0007] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet baffle has a planar area including a plurality of bypass openings, and wherein the scoop includes a solid surface extending at an obtuse angle relative to the planar area.

[0008] In a further non-limiting embodiment of any of the foregoing assemblies, the solid surface extends from the flat region toward an inner peripheral surface of the mixer housing defining the inner cavity, and wherein the solid surface has an edge defining a portion of the first opening.

[0009] In a further non-limiting embodiment of any of the foregoing assemblies, the edge is located downstream of the flat region.

[0010] In a further non-limiting embodiment of any of the foregoing assemblies, the mixer housing includes a metering opening, and wherein a fluid inlet of the inlet reactor is aligned with the metering opening and defines an injection axis, and wherein the first and second exhaust gas inlets are located on opposite sides of the injection axis relative to each other.

[0011] In a further non-limiting embodiment of any of the foregoing components, the inlet reactor includes a vortex chamber, the vortex chamber including at least a first flow element, a second flow element and a third flow element, the first flow element, the second flow element and the third flow element are fixed together to form an internal mixing chamber for injected fluid and exhaust gas, and wherein the first flow element includes a reactor bucket, the reactor bucket defines a first exhaust gas inlet between an inner surface of the reactor bucket and an outer surface of the second flow element, and the outer surface of the second flow element is radially inward of the inner surface relative to the injection axis.

[0012] In a further non-limiting embodiment of any of the foregoing assemblies, the second exhaust gas inlet is defined between an outer surface of the second flow element and an inner surface of a third flow element, the inner surface of the third flow element being radially outward of the outer surface relative to the injection axis.

[0013] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet reactor extends along an injection axis from a first end at a fluid inlet to a second end defining a reactor outlet, and includes an end cap at the reactor outlet, the end cap including a solid base surface surrounded by a peripheral wall, wherein the peripheral wall includes a plurality of outlet openings through which a mixture of fluid and exhaust gas exits the inlet reactor to mix with a bypass flow.

[0014] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet reactor has a larger cross-section at the reactor outlet than at the reactor inlet to form a taper.

[0015] In a further non-limiting embodiment of any of the foregoing assemblies, the inlet reactor includes a meter mounting portion including a meter mounting opening aligned with a meter opening in the mixer housing and defining a fluid inlet.

[0016] According to another exemplary aspect of the present disclosure, a vehicle exhaust system mainly includes: a first exhaust component, a second exhaust component downstream of the first exhaust component, and a mixer positioned downstream of the first exhaust component and upstream of the second exhaust component. The mixer includes a mixer housing, which defines an inner cavity; and an inlet reactor positioned in the inner cavity. The inlet reactor has a fluid inlet, a first exhaust gas inlet, and a second exhaust gas inlet. An inlet baffle is mounted to the upstream end of the mixer housing. The inlet baffle includes a first opening for guiding the exhaust gas into the first exhaust gas inlet, a bucket-shaped portion for guiding the exhaust gas into the second exhaust gas inlet, and a plurality of bypass openings for guiding the exhaust gas to bypass and enter the inlet reactor (bypassing the inlet reactor, not only entering the inlet reactor). The meter mounting opening is located on the outer surface of the mixer housing, and the meter mounting opening is configured to receive a meter to inject a fluid into the fluid inlet.

[0017] In a further non-limiting embodiment of the foregoing system, the inlet baffle has a baffle center and is divided into quadrants spaced circumferentially about the baffle center, and wherein the first opening is located in the first quadrant, the bucket is located in the second quadrant, and the plurality of bypass openings extend across the third and fourth quadrants.

[0018] In a further non-limiting embodiment of any of the foregoing systems, the entire first quadrant comprises open area.

[0019] In a further non-limiting embodiment of any of the foregoing systems, the inlet baffle has a planar area including a plurality of bypass openings, and wherein the scoop includes a solid surface extending at an obtuse angle relative to the planar area.

[0020] In a further non-limiting embodiment of any of the foregoing systems, a solid surface extends from the flat region toward an inner peripheral surface of the mixer housing defining the inner cavity, and wherein the solid surface has an edge defining a portion of the first opening, and wherein the edge extends downstream of the flat region.

[0021] In a further non-limiting embodiment of any of the foregoing systems, a fluid inlet of the inlet reactor is aligned with the meter mounting opening and defines an injection axis, and wherein the first exhaust gas inlet and the second exhaust gas inlet are located on opposite sides of the injection axis relative to each other, and wherein the inlet reactor extends along the injection axis from a first end at the fluid inlet to a second end defining a reactor outlet, and includes an end cap at the reactor outlet, the end cap including a solid base surface, the solid base surface being surrounded by a peripheral wall, and wherein the peripheral wall includes a plurality of outlet openings, and the mixture of fluid and exhaust gas exits the inlet reactor through the outlet openings to mix with the bypass flow.

[0022] In a further non-limiting embodiment of any of the foregoing systems, the inlet reactor includes a vortex chamber, the vortex chamber including at least a first flow element, a second flow element and a third flow element, which are fixed together to form an internal mixing chamber for injected fluid and exhaust gas, and wherein the first flow element includes a reactor bucket, the reactor bucket defines a first exhaust gas inlet between an inner surface of the reactor bucket and an outer surface of the second flow element, the outer surface of the second flow element is radially inward of the inner surface relative to the injection axis, and wherein the second exhaust gas inlet is defined between the outer surface of the second flow element and the inner surface of the third flow element, the inner surface of the third flow element is radially outward of the outer surface relative to the injection axis.

[0023] The embodiments, examples and alternatives of the preceding paragraphs, the claims or the following description and the 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 is like Figure 1 An end view of a mixer used in an exhaust system is shown.

[0026] Figure 3 is like Figure 2 A perspective view of the inlet reactor used in the mixer is shown.

[0027] Figure 4 yes Figure 2 A perspective view of the end of a mixer is shown.

[0028] Figure 5 yes Figure 2 A cross-sectional view of the mixer is shown. DETAILED DESCRIPTION

[0029] The present disclosure details an exemplary mixer that maximizes the inlet flow area of ​​a reactor for directing flow into the mixer to minimize the generation of backpressure.

[0030] Figure 1A 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 gas aftertreatment components include a diesel oxidation catalyst (DOC) 16, and an optional diesel particulate filter (DPF) 18 for removing pollutants from the exhaust gas as is known.

[0031] 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 into 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.

[0032] 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.

[0033] 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 In other examples, doser 36 may inject DEF into the exhaust system at other locations, such as upstream of mixer 30 .

[0034] The control system includes a controller 38 that controls the injection of DEF based on one or more of exhaust gas temperature, back pressure, time, etc. The controller 38 may be a dedicated electronic control unit, or may be an electronic control unit associated with a vehicle system control unit or a subsystem control unit. The controller 38 may include a processor, a memory, and one or more input and / or output (I / O) device interfaces that are communicatively coupled via a local interface. The controller 38 may be a hardware device for executing software, particularly software stored in a memory.

[0035] The mixer 30 is used to generate a swirling motion or a rotating motion of the exhaust gas. Figure 2-5 The mixer 30 is shown in greater detail. The mixer 30 has an inlet end 40 configured to receive the engine exhaust gas and an outlet end 42 that directs the mixture of the swirling engine exhaust gas and the products converted by the injected fluid to the SCR catalyst 22. The mixer 30 includes an inlet baffle 44 ( Figure 2 ). Exit baffle 46 ( Figure 5 ) is associated with the outlet port 42. In one example, the inlet baffle 44 includes a large inlet opening 48 and a bucket 50 that receive a majority of the exhaust gas and direct the exhaust gas to 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.

[0036] 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 5 ). In one example, the baffle comprises a stamped sheet metal part. The inlet reactor 52 is located within the inner cavity 58. The exhaust gas and the injected fluid spray injected into the inlet reactor 52 via the meter 36 mix within the inlet reactor 52 and exit the inner cavity 58 to mix with the bypass exhaust gas before exiting the mixer 30.

[0037] In one example, the inlet reactor 52 is used to facilitate mounting the meter 36 relative to the mixer housing 56. 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 mounted to the mixer housing 56 at a meter opening 64 formed in the mixer housing 56. The meter mounting portion 60 is configured to support the meter 36, which injects fluid into the inner cavity 58 of the mixer housing 56.

[0038] 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 that are attached to each other to form an open interior area within the vortex chamber 62. In one example, the inlet reactor 52 has a fluid inlet 70, a first exhaust gas inlet 72, and a second exhaust gas inlet 74. 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 first exhaust gas inlet 72, the bucket 50 directs the exhaust gas into the second exhaust gas inlet 74, and the plurality of bypass openings 54 direct the exhaust gas to bypass the inlet reactor 52 (not enter the inlet reactor). In one example, the first exhaust gas inlet 72 and the second exhaust gas inlet 74 are on opposite sides of the injection axis I relative to each other.

[0039] In one example, the plurality of flow elements include at least a first flow element 76, a second flow element 78, and a third flow element 80. In one example, the first flow element 76 includes a reactor bucket 82 that defines a first exhaust gas inlet 72 between an inner surface of the reactor bucket 82 and an outer surface of the second flow element 78, the outer surface being radially inward of the inner surface of the reactor bucket 82 relative to the injection axis I. A second exhaust gas inlet 74 is defined between an outer surface of the second flow element 78 and an inner surface of the third flow element 80, the inner surface being radially outward of the outer surface of the second flow element 78 relative to the injection axis I.

[0040] In one example, the inlet reactor 52 extends along the injection axis I from a first end 66 at the fluid inlet 70 to a second end 68 defining a reactor outlet 84. In one example, an end cap 86 is positioned at the reactor outlet 84. The end cap 86 includes a solid base surface 88 with a peripheral wall 90 that surrounds the solid base surface 88 and extends toward the fluid inlet 70. The peripheral wall 90 includes a plurality of outlet openings 92 through which a mixture of fluid and exhaust gas exits the inlet reactor 52 to mix with a bypass flow from the bypass opening 54.

[0041] 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 taper. In one example, the second flow element 78 and the third flow element 80 have a tapered body portion that starts at the first end 66 and extends toward the second end 68, and the second end 68 includes a cylindrical portion (or an elliptical or racetrack shape) whose cross-section is generally constant.

[0042] As described above, the inlet reactor 52 includes a meter mounting portion 60 including a meter mounting opening that forms the fluid inlet 70 and is aligned with the meter opening 64 in the mixer housing 56. The second flow element 78 and the third flow element 80 are fixed to each other generally about the injection axis I. The first flow element 76 has an arm portion 94 at the downstream end that is fixed to the second flow element 78. The reactor bucket 82 of the first flow element 76 includes a curved wall portion 96 and a base wall portion 98 that cooperate to form an enlarged bucket opening for the first exhaust gas inlet 72.

[0043] In one example, the curved wall portion 96 transitions to the meter mounting portion 60. The meter mounting portion 60 includes a central boss 100 having a fluid inlet 70 defining an injection axis I.

[0044] In one example, the inlet baffle 44 has a baffle center C and is divided into a plurality of sections spaced circumferentially about the baffle center C. In one example, the plurality of sections include (a plurality of) quadrants Q1-Q4 spaced circumferentially about the baffle center C. The large inlet opening 48 is in the first quadrant Q1, the bucket 50 is in the second quadrant Q2, and the plurality of bypass openings 54 extend across the third quadrant Q3 and the fourth quadrant Q4. In one example, the first quadrant Q1 of the entire inlet baffle 44 includes an open area to maximize the inlet flow rate.

[0045] In one example, the inlet baffle 44 has a flat area 102 including a plurality of bypass openings 54, while the bucket 50 includes a solid surface 104 extending at an obtuse angle α relative to the flat area 102. The solid surface 104 extends from the flat area 102 toward an inner peripheral surface 106 of the mixer housing 56, which defines the inner cavity 58. The solid surface 104 has an edge 108 that defines a portion of the large inlet opening 48. The edge 108 is downstream of the flat area 102. In one example, the inlet baffle 44 can include an additional indentation 110 for additional components, such as a sensor.

[0046] The present disclosure provides an inlet baffle that allows exhaust gas to flow into a reactor and allows a portion of the gas flow to bypass the reactor. The reactor guides and directs the flow near the spray. By using one quadrant of the inlet baffle as a bucket to direct the flow area into one side of the reactor, a maximized inlet flow area is achieved to direct the flow directly into the inlet reactor. The flow entering the opposite side of the reactor is accomplished by completely removing the inlet baffle in the quadrant and increasing the size of the sheet metal bucket that is part of the reactor. Therefore, the present disclosure achieves high mixing performance in a compact mixer to maximize the inlet flow area for directing the flow into the reactor, thereby minimizing the generation of back pressure.

[0047] 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.

[0048] 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 determined by studying the following claims.

Claims

1. A mixer assembly for a vehicle exhaust system, comprising: a mixer housing defining an inner cavity extending along a central axis of the mixer from an upstream end to a downstream end; an inlet reactor positioned within the inner cavity, the inlet reactor having a fluid inlet, a first exhaust gas inlet, a second exhaust gas inlet, and a plurality of outlet openings; as well as an inlet baffle mounted to the upstream end of the mixer housing, the inlet baffle comprising a first opening for directing exhaust gas into the first exhaust gas inlet, a bucket for directing exhaust gas into the second exhaust gas inlet, and a plurality of bypass openings for directing exhaust gas to bypass entry of the inlet reactor, and wherein at least some of the plurality of bypass openings are spaced apart from one another in a radial direction relative to a central axis of the mixer; wherein the inlet baffle has a baffle center and is divided into a plurality of sections spaced apart in a circumferential direction around the baffle center, wherein the first opening is located in a first section of the plurality of sections, the bucket-shaped portion is located in a second section of the plurality of sections separated from the first section, and the plurality of bypass openings are located in a third section of the plurality of sections separated from the first section and the second section.

2. The mixer assembly according to claim 1, characterized in that The third segment is located on an opposite side of the center of the baffle from the first segment and the second segment.

3. The mixer assembly according to claim 1, characterized in that The plurality of segments include four quadrants, wherein the first segment includes a first quadrant, the second segment includes a second quadrant, and the third segment extends across a third quadrant and a fourth quadrant of the four quadrants.

4. The mixer assembly according to claim 1, characterized in that The inlet baffle has a planar area including the plurality of bypass openings, and wherein the bucket includes a solid surface extending at an obtuse angle relative to the planar area.

5. The mixer assembly according to claim 4, characterized in that The solid surface extends from the flat region toward an inner peripheral surface of the mixer housing that defines the inner cavity, and wherein the solid surface has an edge that defines a portion of the first opening.

6. The mixer assembly according to claim 5, characterized in that The edge is downstream of the flat region.

7. The mixer assembly according to claim 1, characterized in that The mixer housing includes a meter opening, wherein the fluid inlet of the inlet reactor is aligned with the meter opening and defines an injection axis, wherein the first and second exhaust gas inlets are located on opposite sides of the injection axis relative to each other.

8. The mixer assembly according to claim 7, characterized in that The inlet reactor includes a vortex chamber, which includes at least a first flow element, a second flow element and a third flow element, wherein the first flow element, the second flow element and the third flow element are fixed together to form an internal mixing chamber for injected fluid and exhaust gas, and wherein the first flow element includes a reactor bucket-shaped portion, the first exhaust gas inlet is defined between the inner surface of the reactor bucket-shaped portion and the outer surface of the second flow element, and the outer surface of the second flow element is radially inward of the inner surface relative to the injection axis.

9. The mixer assembly according to claim 8, characterized in that The second exhaust gas inlet is defined between the outer surface of the second flow element and an inner surface of the third flow element, the inner surface of the third flow element being radially outward of the outer surface relative to the injection axis.

10. The mixer assembly according to claim 9, characterized in that The inlet reactor has a larger cross section at the reactor outlet than at the reactor inlet to form a taper.

11. The mixer assembly according to claim 7, characterized in that The inlet reactor extends along the injection axis from a first end at the fluid inlet to a second end defining a reactor outlet, and includes an end cap located at the reactor outlet, the end cap including a solid base surface, the solid base surface being surrounded by a peripheral wall, wherein the peripheral wall includes the plurality of outlet openings, and the mixture of fluid and exhaust gas leaves the inlet reactor through the plurality of outlet openings to mix with the bypass flow.

12. The mixer assembly according to claim 7, characterized in that The inlet reactor includes a meter mounting portion including a meter mounting opening that aligns with the meter opening in the mixer housing and defines the fluid inlet.

13. The mixer assembly according to claim 1, characterized in that The plurality of bypass openings comprises a plurality of discrete openings spaced radially inwardly of an outer peripheral edge of the inlet baffle, and wherein the plurality of discrete openings are circumferentially and radially spaced from one another relative to the mixer central axis.

14. The mixer assembly according to claim 1, characterized in that The first opening is entirely in a first segment of the plurality of segments.

15. The mixer assembly according to claim 1, characterized in that The inlet reactor extends along an injection axis from a first end at the fluid inlet to a second end defining a reactor outlet, and includes an end cap at the reactor outlet, the end cap including a solid base surface, the solid base surface being spaced apart from the inner surface of the mixer housing and having a peripheral wall surrounding the solid base surface, and wherein the peripheral wall includes a plurality of outlet openings, through which a mixture of fluid and exhaust gas exits the inlet reactor to mix with a bypass flow, and wherein at least some of the plurality of bypass openings overlap with the plurality of outlet openings.

16. A vehicle exhaust system comprising: a first exhaust component; a second exhaust component located downstream of the first exhaust component; a mixer located downstream of the first exhaust component and upstream of the second exhaust component, the mixer comprising: a mixer housing defining an inner cavity extending along a central axis of the mixer from an upstream end to a downstream end, an inlet reactor positioned within the inner cavity, the inlet reactor having a fluid inlet, a first exhaust gas inlet, a second exhaust gas inlet, and a plurality of outlet openings, and an inlet baffle mounted to the upstream end of the mixer housing, the inlet baffle comprising a first opening for directing exhaust gas into the first exhaust gas inlet, a bucket for directing exhaust gas into the second exhaust gas inlet, and a plurality of bypass openings for directing exhaust gas to bypass entry of the inlet reactor, and wherein at least some of the plurality of bypass openings are spaced apart from one another in a radial direction relative to a central axis of the mixer; wherein the inlet baffle has a baffle center and is divided into quadrants spaced circumferentially about the baffle center, and wherein the first opening is located in a first quadrant, the bucket is located in a second quadrant, and the plurality of bypass openings extend across a third quadrant and a fourth quadrant; and A meter mounting opening is located on an outer surface of the mixer housing, the meter mounting opening being configured to receive a meter to inject a fluid into the fluid inlet.

17. The vehicle exhaust system according to claim 16, characterized in that The entire first quadrant comprises open area.

18. The vehicle exhaust system according to claim 16, characterized in that The inlet baffle has a planar area including the plurality of bypass openings, and wherein the bucket includes a solid surface extending at an obtuse angle relative to the planar area.

19. The vehicle exhaust system according to claim 18, characterized in that The solid surface extends from the flat region toward an inner peripheral surface of the mixer housing, the inner peripheral surface defining the inner cavity, and wherein the solid surface has an edge that defines a portion of the first opening, and wherein the edge extends downstream from the flat region.

20. The vehicle exhaust system of claim 16, wherein: The fluid inlet of the inlet reactor is aligned with the meter mounting opening and defines an injection axis, and wherein the first exhaust gas inlet and the second exhaust gas inlet are located on opposite sides of the injection axis relative to each other, and wherein the inlet reactor extends along the injection axis from a first end at the fluid inlet to a second end defining a reactor outlet, and includes an end cap at the reactor outlet, the end cap including a solid base surface, the solid base surface being surrounded by a peripheral wall, and wherein the peripheral wall includes the plurality of outlet openings, and the mixture of fluid and exhaust gas leaves the inlet reactor through the outlet openings to mix with the bypass flow.

21. The vehicle exhaust system of claim 16, wherein: The inlet reactor includes a vortex chamber, which includes at least a first flow element, a second flow element and a third flow element, wherein the first flow element, the second flow element and the third flow element are fixed together to form an internal mixing chamber for injected fluid and exhaust gas, and wherein the first flow element includes a reactor bucket, and the reactor bucket defines the first exhaust gas inlet between the inner surface of the reactor bucket and the outer surface of the second flow element, and the outer surface of the second flow element is radially inward of the inner surface relative to the injection axis, and wherein the second exhaust gas inlet is defined between the outer surface of the second flow element and the inner surface of the third flow element, and the inner surface of the third flow element is radially outward of the outer surface relative to the injection axis.

22. The vehicle exhaust system of claim 16, wherein: The plurality of bypass openings comprises a plurality of discrete openings spaced radially inwardly of an outer peripheral edge of the inlet baffle, and wherein the plurality of discrete openings are circumferentially and radially spaced from one another relative to the mixer central axis.

23. The vehicle exhaust system of claim 16, wherein: The first opening is entirely in the first quadrant.

24. The vehicle exhaust system of claim 16, wherein: The inlet reactor extends along an injection axis from a first end at the fluid inlet to a second end defining a reactor outlet, and includes an end cap at the reactor outlet, the end cap including a solid base surface, the solid base surface being spaced apart from the inner surface of the mixer housing and having a peripheral wall surrounding the solid base surface, and wherein the peripheral wall includes a plurality of outlet openings, through which a mixture of fluid and exhaust gas exits the inlet reactor to mix with a bypass flow, and wherein at least some of the plurality of bypass openings overlap with the plurality of outlet openings.

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