Patent Description:
Typically, work vehicles, such as tractors and other agricultural vehicles, include an exhaust treatment system for controlling engine emissions. As is generally understood, exhaust treatment systems for work vehicles often include a diesel oxidation catalyst (DOC) system in fluid communication with a selective catalytic reduction (SCR) system. The DOC system is generally configured to oxidize carbon monoxide and unburnt hydrocarbons contained within the engine exhaust and may include a mixing chamber for mixing an exhaust reductant, such as a diesel exhaust fluid (DEF) or any other suitable urea-based fluid, into the engine exhaust. For instance, the exhaust reductant is often pumped from a reductant tank mounted on and/or within the vehicle and injected into the mixing chamber to mix the reductant with the engine exhaust. The resulting mixture may then be supplied to the SCR system to allow the reductant to be reacted with a catalyst in order to reduce the amount of nitrogen oxide (NOx) emissions contained within the engine exhaust. A NOx sensor is typically positioned downstream of the SCR system to monitor the amount of NOx emissions still remaining in the exhaust flow exiting the exhaust treatment system. The data from the sensor may, for example, be used to control the combustion temperature of the engine and/or the amount of reductant injected into the mixing chamber to ensure that the amount of NOx emissions remains below a given amount.

In many instances, the NOx sensor is positioned close to the outlet of the SCR system. As such, the exhaust gases from different substrate channels do not have time to sufficiently mix before reaching the NOx sensor. As such, the NOx sensor tends to read exhaust gases from only one substrate channel, which significantly reduces the accuracy of the sensor readings and thus, the overall performance of the treatment system.

Accordingly, an improved exhaust treatment system for work vehicles and related flow mixers would be welcomed in the technology.

<CIT>, <CIT>, <CIT> and <CIT> disclose respective examples of flow mixers.

In one aspect, the present subject matter is directed to an exhaust treatment system for a work vehicle. The system may include a selective catalytic reduction (SCR) system configured to react a mixture of exhaust reductant and engine exhaust with a catalyst to generate a treated exhaust flow, with the SCR system including an SCR outlet for expelling the treated exhaust flow therefrom. The system may further include a flow conduit in fluid communication with the SCR outlet for receiving the treated exhaust flow expelled from the SCR system. Further, the system may include an exhaust sensor positioned within the flow conduit downstream of the SCR outlet, with the exhaust sensor being configured to detect an amount of an emission gas present in the treated exhaust flow. Additionally, the system may include a flow mixer positioned upstream of the exhaust sensor. The flow mixer may have an end wall defining sector openings extending in a circumferential direction of the flow mixer between a first sector side and a second sector side and in a radial direction of the flow mixer between a radially inner sector end and a radially outer sector end. Moreover, the flow mixer may have a plurality of swirler vanes, where each of the plurality of swirler vanes extends in the circumferential direction from the first sector side of a respective one of the sector openings and in the radial direction between a radially inner vane end and a radially outer vane end. Particularly, the radially outer vane end of each of the plurality of swirler vanes may be spaced apart in the radial direction from the radially outer sector end of the respective one of the sector openings. As such, the plurality of swirler vanes is configured to impart a spiraling flow trajectory to the treated exhaust flow flowing from the SCR to the exhaust sensor.

In another aspect, the present subject matter is directed to an exhaust treatment system for a work vehicle. The system may include a selective catalytic reduction (SCR) system configured to react a mixture of exhaust reductant and engine exhaust with a catalyst to generate a treated exhaust flow, where the SCR system includes an SCR outlet for expelling the treated exhaust flow therefrom. The system may further include a flow conduit in fluid communication with the SCR outlet for receiving the treated exhaust flow expelled from the SCR system. Further, the system may include an exhaust sensor positioned within the flow conduit downstream of the SCR outlet, with the exhaust sensor being configured to detect an amount of an emission gas present in the treated exhaust flow. Additionally, the system may include a flow mixer positioned upstream of the exhaust sensor, with the flow mixer extending between an upstream end and a downstream end along an axial direction. The flow mixer may have a sidewall extending between the upstream and downstream ends, with the sidewall defining a plurality of sidewall openings. Each of the plurality of sidewall openings may extend in the axial direction across a first axial range. Further, the flow mixer may have an end wall coupled to the sidewall proximate the upstream end, the end wall defining sector openings. Additionally, the flow mixer may have a plurality of swirler vanes, where each of the plurality of swirler vanes extends in a circumferential direction of the flow mixer from adjacent a respective one of the sector openings and in the axial direction across a second axial range, with the first axial range at least partially overlapping the second axial range. The plurality of swirler vanes is configured to impart a spiraling flow trajectory to the treated exhaust flow flowing from the SCR to the exhaust sensor.

In an additional aspect, the present subject matter is directed to a flow mixer for use within an exhaust treatment system of a work vehicle. The flow mixer may have a sidewall extending between an upstream end and a downstream end along an axial direction, where the sidewall defines a plurality of sidewall openings. Each of the plurality of sidewall openings extends in the axial direction across a first axial range. Further, the flow mixer may include an end wall coupled to the sidewall proximate the upstream end, with the end wall defining sector openings extending in a radial direction of the flow mixer across a first radial distance. Additionally, the flow mixer may have a plurality of swirler vanes, with each of the plurality of swirler vanes extending in a circumferential direction of the flow mixer from a respective one of the sector openings and in the radial direction across a second radial distance and in the axial direction across a second axial range. Particularly, the second radial distance is less than the first radial distance, and the first axial range at least partially overlaps the second axial range.

In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention.

In general, the present subject matter is directed to an exhaust treatment system for a work vehicle. In several embodiments, the exhaust treatment system includes a flow mixer adapted to increase the mixing of exhaust gases from different substrate channels exiting a selective catalytic reduction (SCR) system before the exhaust gases reach a sensor, such as a nitrogen oxide (NOx) sensor. For example, the flow mixer may be positioned at a location upstream of the exhaust sensor such that the mixer imparts a spiraling flow trajectory to the flow of treated exhaust from the SCR system. In one embodiment, the flow mixer has an end wall that defines a plurality of sector openings. The flow mixer further has swirler vanes, where each of the swirler vanes extends from a respective one of the plurality of sector openings. Particularly, in some embodiments, each swirler vane only extends over part of the radial distance across which the respective sector openings extends. For example, in some embodiments, a radially outer end of each of the vanes may be spaced apart from a radial outer end of the respective one of the plurality of sector openings. Further, the flow mixer may include a sidewall extending between the upstream and downstream ends, where the sidewall similarly defines a plurality of circumferentially spaced sidewall openings. The sidewall openings and the vanes at least partially overlap along an axial direction of the flow mixer. The end wall, in such embodiments, may be coupled to the sidewall proximate an upstream end of the flow mixer.

Exhaust gases may flow through the sector openings and the sidewall openings to exit the SCR system, where the swirler vanes create a spiral flow of the exhaust gases to better mix the exhaust gases before the exhaust gases flow past the exhaust sensor. As such, the NOx sensor may more accurately monitor the amount of NOx emissions remaining in the exhaust flow based at least in part on the mixed exhaust gases. Additionally, due to the relatively open configuration of the flow mixer by having such sector and sidewall openings, mixing of the exhaust gases is accomplished with very little backpressure being created in the exhaust treatment system.

Referring now to the drawings, <FIG> illustrates a side view of one embodiment of a work vehicle <NUM>. As shown, the work vehicle <NUM> is configured as an agricultural tractor. However, in other embodiments, the work vehicle <NUM> may be configured as any other suitable work vehicle known in the art, such as various other agricultural vehicles, earth-moving vehicles, road vehicles, all-terrain vehicles, off-road vehicles, loaders, and/or the like.

As shown in <FIG>, the work vehicle <NUM> includes a pair of front wheels <NUM>, a pair of rear wheels <NUM>, and a chassis <NUM> coupled to and supported by the wheels <NUM>, <NUM>. An operator's cab <NUM> may be supported by a portion of the chassis <NUM> and may house various control devices <NUM>, <NUM> (e.g., levers, pedals, control panels and/or the like) for permitting an operator to control the operation of the work vehicle <NUM>. Additionally, the work vehicle <NUM> may include an engine <NUM> and a transmission <NUM> mounted on the chassis <NUM>. The transmission <NUM> may be operably coupled to the engine <NUM> and may provide variably adjusted gear ratios for transferring engine power to the wheels <NUM> via a differential <NUM>.

Moreover, the work vehicle <NUM> may also include an exhaust treatment system <NUM> for reducing the amount of emissions contained within the exhaust from the engine <NUM>. For instance, engine exhaust expelled from the engine <NUM> may be directed through the exhaust treatment system <NUM> to allow the levels of nitrogen oxide (NOx) emissions contained within the exhaust to be reduced significantly. The cleaned or treated exhaust gases may then be expelled from the exhaust treatment system <NUM> into the surrounding environment via an exhaust pipe <NUM> of the work vehicle <NUM>.

It should be appreciated that the configuration of the work vehicle <NUM> described above and shown in <FIG> is provided only to place the present subject matter in an exemplary field of use. Thus, it should be appreciated that the present subject matter may be readily adaptable to any manner of work vehicle configuration <NUM>. For example, in an alternative embodiment, a separate frame or chassis may be provided to which the engine <NUM>, transmission <NUM>, and differential <NUM> are coupled, a configuration common in smaller tractors. Still other configurations may use an articulated chassis to steer the work vehicle <NUM>, or rely on tracks in lieu of the wheels <NUM>, <NUM>. Additionally, although not shown, the work vehicle <NUM> may also be configured to be operably coupled to any suitable type of work implement, such as a trailer, spray boom, manure tank, feed grinder, plow and/or the like.

Referring now to <FIG>, a schematic diagram of one embodiment of an exhaust treatment system <NUM> suitable for use with a work vehicle <NUM> is illustrated in accordance with aspects of the present subject matter. As represented in <FIG>, the exhaust treatment system includes an exhaust conduit <NUM>, a diesel oxidation catalyst (DOC) system <NUM>, a mixing conduit <NUM>, a selective catalytic reduction (SCR) system <NUM>, and a treated exhaust flow conduit <NUM>. During operation of the work vehicle <NUM>, exhaust expelled from the engine <NUM> is received by the exhaust conduit <NUM> and flows through the conduit <NUM> to the DOC system <NUM>. As is generally understood, the DOC system <NUM> is configured to reduce the levels of carbon monoxide and hydrocarbons present in the engine exhaust. For example, as shown in <FIG>, the DOC system <NUM> includes a canister or chamber <NUM> for receiving engine exhaust from the exhaust conduit <NUM>, with the chamber <NUM> being in flow communication with an upstream end <NUM> of the mixing conduit <NUM>. In addition, the DOC system <NUM> includes a reductant injector nozzle <NUM> provided in association with the chamber <NUM> at a location at or adjacent to the upstream end <NUM> of the mixing conduit <NUM> to allow an exhaust reductant <NUM>, such as a diesel exhaust fluid (DEF) or any other suitable urea-based fluid, to be injected into the stream of exhaust gases flowing through the chamber <NUM>. For instance, as shown in <FIG>, the reductant injector nozzle <NUM> may be fluidly coupled to a source of exhaust reductant (e.g., storage tank <NUM>) via a hose or other fluid coupling <NUM> to allow liquid exhaust reductant to be supplied to the nozzle <NUM>. The engine exhaust and exhaust reductant flowing into the upstream end <NUM> of the mixing conduit <NUM> are then directed through the conduit <NUM> to the downstream end <NUM> thereof for receipt by the SCR system <NUM>, within which the mixture of exhaust/reductant is reacted with a catalyst to generate a treated exhaust flow in which the amount of harmful or undesirable gas emissions has been reduced as compared to the engine exhaust initially discharged from the engine <NUM>. The treated exhaust flow is then expelled from an outlet <NUM> of the SCR system <NUM> and is directed through the downstream flow conduit <NUM> for discharge into the atmosphere (e.g., via an exhaust pipe <NUM> forming part of or coupled to the downstream flow conduit <NUM>).

Additionally, as shown in <FIG>, the exhaust treatment system <NUM> includes an exhaust sensor <NUM> positioned within the downstream flow conduit <NUM> to monitor the concentration or amount of emissions remaining within the treated exhaust flow following treatment within the SCR system <NUM>. In one embodiment, the exhaust sensor <NUM> comprises one or more nitrogen oxide (NOx) sensors configured to detect the amount of NOx contained within the treated exhaust flow. However, in other embodiments, the exhaust sensor <NUM> may comprise any other suitable sensor(s) or combination of sensor(s) configured to detect the concentration or amount of gaseous emissions contained within the treated exhaust flow, including the detection of gaseous emissions other than NOx and/or the detection of NOx in combination with one or more other gaseous emissions. As shown, in <FIG>, in one embodiment, the exhaust sensor <NUM> is communicatively coupled to a controller <NUM> (e.g., a computing device or another other suitable processor-based device) configured to monitor the exhaust emissions contained within the treated exhaust flow based on the data received from the sensor <NUM>. The controller <NUM> may then, for example, compare the concentration or amount of detected exhaust emissions to a predetermined limit or threshold and control one or more components of the work vehicle <NUM> based on such comparison, such as by adjusting the combustion temperature of the engine <NUM> and/or varying the amount of reductant injected into the DOC system <NUM> to ensure that the exhaust emissions remain below the predetermined limit or threshold.

Moreover, the exhaust treatment system <NUM> may also include a flow mixer <NUM> positioned at or adjacent to the outlet <NUM> of the SCR system <NUM>. As will be described in greater detail below, the flow mixer <NUM> may be configured to impart a rotating or spiraling flow trajectory to the treated exhaust flow expelled from the SCR system <NUM>, which may facilitate enhanced mixing of the treated exhaust immediately upstream of the exhaust sensor <NUM>, thereby allowing the sensor <NUM> to provide more accurate data related to the concentration or amount of the gaseous emission(s) (e.g., NOx) being monitored.

Referring now to <FIG>, a cross-sectional view of a portion of the exhaust treatment system shown in <FIG> within box <NUM>-<NUM> is illustrated in accordance with aspects of the present subject matter, particularly illustrating one embodiment of a flow mixer positioned relative to an outlet of the selective catalytic reduction (SCR) system. As indicated above, in several embodiments, the flow mixer <NUM> is configured to be positioned at or adjacent to the outlet <NUM> of the SCR system <NUM>. For example, in the illustrated embodiment, the flow mixer <NUM> is positioned immediately at the interface between the SCR outlet <NUM> and an adjacent upstream end <NUM> of the flow conduit <NUM>. The flow mixer <NUM> generally extends between an upstream end <NUM> and a downstream end <NUM> along an axial direction L1. The downstream end <NUM> of the flow mixer <NUM> is configured to be positioned at or adjacent the outlet <NUM> of the SCR system <NUM> such that the downstream end <NUM> of the flow mixer <NUM> is positioned closer to the outlet <NUM> than the upstream end <NUM> of the flow mixer <NUM>. However, in other embodiments, the flow mixer <NUM> may be positioned at any other suitable location relative to the SCR outlet <NUM>, such as at a location upstream of the interface between the SCR outlet <NUM> and the upstream end <NUM> of the flow conduit <NUM> or at a location downstream of the interface and upstream of the exhaust sensor <NUM>.

Additionally, as shown in <FIG>, the exhaust sensor <NUM> may be configured to extend radially inwardly from an inner surface <NUM> of the flow conduit <NUM> such that at least a portion of the sensor <NUM> is positioned directly within and/or otherwise directly exposed to the flow of treated exhaust flowing downstream of the mixer <NUM>. In this regard, it should be noted that the exhaust sensor <NUM> is not shielded or otherwise protected from the flow of treated exhaust via an upstream deflector. Rather, a portion of the treated exhaust flow flows directly into and/or across the exhaust sensor <NUM> to allow the sensor <NUM> to provide accurate data relating to the gaseous emission(s) being monitored.

As will be described below in greater detail, the flow mixer <NUM> has a plurality of openings through which exhaust gases flow before reaching the exhaust sensor <NUM>, and a plurality of vanes for creating a swirling trajectory of the exhaust gases flowing through the flow mixer <NUM>. For instance, a first portion F1 and a second portion F2 of the treated exhaust flow expelled from the SCR system <NUM> may flow through openings at the upstream end <NUM> of the flow mixer <NUM>, while a third portion F3 of the treated exhaust flow expelled from the SCR system <NUM> may flow through openings along a sidewall of the flow mixer <NUM>. The first portion F1 of the exhaust gases may impinge on swirler vanes proximate the openings at the upstream end <NUM> such that the first portion F1 of the exhaust gases is given a swirling trajectory. The second portion F2 of the exhaust gases may generally flow past the ends of swirler vanes, which also at least partially prevents the third portion F3 of the exhaust gases from being drawn through the swirler vanes. The swirling trajectory of the first portion F1 of the exhaust gases helps to mix the first portion F1 with the other portions F2, F3 of the exhaust gases, while very little backflow pressure is created by the flow mixer <NUM>.

Referring now to <FIG>, differing views of the flow mixer <NUM> are illustrated in accordance with the present subject matter. Specifically, <FIG> illustrates a perspective view of the flow mixer <NUM>, <FIG> illustrates a bottom view of the flow mixer <NUM>, and <FIG> illustrates a side view of the flow mixer <NUM>. As shown in <FIG>, the mixer <NUM> includes an end wall <NUM> and a sidewall <NUM> coupled to the end wall <NUM>, proximate the upstream end <NUM> of the mixer <NUM>.

As particularly shown in <FIG>, the end wall <NUM> defines a plurality of sector openings <NUM>. Each of the sector openings <NUM> extends in a circumferential direction CD1 between a first sector side <NUM> and a second sector side <NUM> and extends in a radial direction R1 between a radially inner sector end <NUM> and a radially outer sector end <NUM> across a first radial distance D1 (<FIG>). As particularly shown in <FIG>, the first sector side <NUM> of each sector opening <NUM> extends at a first angle B1 relative to the second sector side <NUM> such that each sector opening <NUM> forms a wedge shape, with the sector sides <NUM>, <NUM> being closer together at the radially inner sector end <NUM> than at the radially outer sector end <NUM>. The radially inner sector ends <NUM> of the sector openings <NUM> are spaced apart radially from a center axis C1 by a gap distance GD. In some embodiments, the sector openings <NUM> are evenly spaced apart in the circumferential direction CD1 by an angle B2 about the center axis C1 of the end wall <NUM>. However, in one or more embodiments, the sector openings <NUM> may be spaced apart by varying angles about the center axis C1. In one embodiment, the angle B1 between the first and second sector sides <NUM>, <NUM> is equal to the angle B2 between sector openings <NUM>. However, in other embodiments, the angles B1, B2 may be different from each other.

It should be appreciated that while the end wall <NUM> is shown as defining eight sector openings <NUM>, the end wall <NUM> may define any other suitable number of sector openings <NUM>. For instance, the end wall <NUM> may instead define two, three, four, five, six, eight or more sector openings <NUM>. Preferably, in some embodiments, the sector openings <NUM> collectively cover between about <NUM>% and about <NUM>% of the end wall <NUM>, such as between about <NUM>% and about <NUM>% of the end wall <NUM>, such as about <NUM>% of the end wall <NUM>.

As further shown in <FIG>, the end wall <NUM> includes a plurality of swirler vanes <NUM> configured to impart a rotating or spiraling flow trajectory to the treated exhaust flow expelled from the SCR system <NUM> (<FIG>). Each of the swirler vanes <NUM> is associated with a respective one of the sector openings <NUM>. For instance, each swirler vane <NUM> extends from the first sector side <NUM> of a respective sector opening <NUM> at an angle B3 (<FIG> and <FIG>), such that the swirler vanes <NUM> extend toward the downstream end <NUM> of the flow mixer <NUM> and at least partially vertically above the respective sector opening <NUM>. For instance, the angle B3 between the sector openings <NUM> and the swirler vanes <NUM> is about <NUM>°. However, it should be appreciated that the swirler vanes <NUM> may be oriented at any other suitable angle relative to the sector openings <NUM>.

As particularly shown in <FIG>, each swirler vane <NUM> (also referred to herein as simply "vane <NUM>") extends in the circumferential direction CD1 between a first vane side <NUM> and a second vane side <NUM> and extends in the radial direction R1 between a radially inner vane end <NUM> and a radially outer vane end <NUM> over a second radial distance D2 (<FIG>). In one embodiment, a width of each vane <NUM> between the first and second vane sides <NUM>, <NUM> corresponds to a width of the respective sector opening <NUM> between the first and second sector sides <NUM>, <NUM> along the second radial distance D2 such that the vane <NUM> would extend fully across the width of the sector opening <NUM> in the circumferential direction if the vane <NUM> was not angled relative to the end wall <NUM> (e.g., at angle B3). The first vane side <NUM> of each vane <NUM> is adjacent the first sector side <NUM> of the respective sector opening <NUM>. Additionally, in one embodiment, the radially inner vane end <NUM> of the first vane side <NUM> of each vane <NUM> may be at the radially inner sector end <NUM> of the first sector side <NUM> of the respective sector opening <NUM>.

In some embodiments, the radially outer vane end <NUM> of each vane <NUM> is spaced apart from the radially outer sector end <NUM> of the respective sector opening <NUM>. For instance, in one embodiment, the second radial distance D2 (<FIG>) is about <NUM>% of the first radial distance D1 (<FIG>). In such embodiments, the first portion F1 of the treated exhaust flow expelled from the SCR system <NUM> (<FIG>) flows through a first portion of sector openings <NUM> that overlaps with the second radial distance D2, such that the first portion of the treated exhaust flow is given a counter-clockwise rotating or spiraling flow trajectory as it is guided by the vanes <NUM>, while the second portion F2 of the treated exhaust flow expelled from the SCR system <NUM> (<FIG>) may flow through a second portion of the sector openings <NUM> that does not overlap with the second radial distance D2, such that the second portion of the treated exhaust flow flows past the radially outer vane ends <NUM> of the vanes <NUM>. As the second portion F2 of the treated exhaust flow bypasses the vanes <NUM>, the second portion F2 has a more linear trajectory, which helps to at least partially reduce or avoid backpressure of the flow mixer <NUM>. The swirling trajectory of the first portion F1 causes the second portion F2 to mix into the first portion F1.

In some embodiments, such as the embodiment illustrated, the number of vanes <NUM> generally matches the number of sector openings <NUM> such that each sector opening <NUM> is associated with a respective vane <NUM>. However, it should be appreciated that, in some embodiments, the number of sector openings <NUM> may be greater than the number of vanes <NUM> such that some of the sector openings <NUM> may not have an associated vane <NUM>. Additionally, it should be appreciated that, in general, a higher number of vanes <NUM> may have a better mixing performance than a smaller number of vanes <NUM> with the same, total surface area.

As shown in <FIG> and <FIG>, the sidewall <NUM> generally extends between the upstream end <NUM> and the downstream end <NUM> of the flow mixer <NUM>. Particularly, the sidewall <NUM> extends between a first axial sidewall end <NUM> and a second axial sidewall end <NUM>, with the first axial sidewall end <NUM> being proximate the upstream end <NUM> of the flow mixer <NUM> and the second axial end <NUM> being proximate the downstream end <NUM> of the flow mixer. The end wall <NUM> is coupled to the sidewall <NUM> at the first axial sidewall end <NUM>. In one embodiment, the sidewall <NUM> is annular or cylindrical. However, it should be appreciated that the sidewall <NUM> may have any other suitable shape.

The sidewall <NUM> defines a plurality of sidewall openings <NUM> through which the third portion F3 (<FIG>) of the treated exhaust flow expelled from the SCR system <NUM> (<FIG>) may flow. Each of the sidewall openings <NUM> extends in the circumferential direction CD1 between a first sidewall side <NUM> and a second sidewall side <NUM>, and in the axial direction L1 between a first axial sidewall end <NUM> and a second axial sidewall end <NUM> over a first axial range A1. In one embodiment, the first and second sidewall sides <NUM>, <NUM> are parallel to the axial direction L1, while the first and second axial sidewall ends <NUM>, <NUM> are generally perpendicular to the axial direction L1. As shown in <FIG>, each of the sector openings <NUM> is associated with one or more of the sidewall openings <NUM>. For instance, in one embodiment, each of the sector openings <NUM> is at least partially radially aligned with one or more of the sidewall openings <NUM>. In one embodiment, such as the embodiment shown, the sidewall <NUM> includes eleven sidewall openings <NUM> evenly spaced apart about the center axis C1 of the flow mixer <NUM> in the circumferential direction CD1. However, in other embodiments, the sidewall <NUM> may include any other suitable number of sidewall openings <NUM>. Preferably, in some embodiments, the sidewall openings <NUM> collectively cover between about <NUM>% and about <NUM>% of the sidewall <NUM>, such as about <NUM>% of the sidewall <NUM>. It should be appreciated that, as will be described below, the total coverage percentages of the sidewall openings <NUM> and the sector openings <NUM> are selected such that the portions of treated exhaust flow through the end wall <NUM> and the sidewall <NUM> are approximately equal.

Further, as particularly shown in <FIG>, the vanes <NUM> are angled relative to the end wall <NUM> such that each vane <NUM> extends in the axial direction L1 from the end wall <NUM> along a second axial range A2. In one embodiment, the sidewall openings <NUM> are positioned such that the first and second axial ranges A1 and A2 at least partially overlap. Particularly, the second axial sidewall end <NUM> of each of the sidewall openings <NUM> may be spaced axially apart from the radially outer vane ends <NUM> along the axial direction L1 such that the first axial range A1 extends closer to the downstream end <NUM> of the flow mixer <NUM> than the second axial range A2. As such, at least part of the third portion F3 of the treated exhaust flow may enter the flow mixer <NUM> in the axial gap defined between the radially outer vane ends <NUM> of the vanes <NUM> and the second axial sidewall ends <NUM> of the sidewall openings <NUM>, thereby avoiding the vanes <NUM>. In some embodiments, the remaining part of the third portion F3 of the treated exhaust flow that enters the flow mixer <NUM> at the vanes <NUM> may be at least partially guided away from the vanes <NUM> by the second portion F2 of the treated exhaust flow flowing past the ends of the vanes <NUM>. As such, the second and third portions F2 may mix at the sidewall openings <NUM>, while further mixing with the first portion F1 at a location closer to the downstream end <NUM> of the flow mixer <NUM>. By allowing the second and third portions F2, F3 of the exhaust gases to at least partially avoid the vanes <NUM>, backpressure of the SCR system <NUM> is at least partially avoided or reduced.

It should be appreciated that, although the mixer configuration shown in <FIG> is generally described herein with reference to mixing the flow of exhaust gases directed between the SCR system <NUM> and the downstream exhaust sensor <NUM>, the flow mixer <NUM> may also be utilized in one or more additional locations within the exhaust treatment system <NUM>. For instance, in addition to being located between the SCR system <NUM> and the downstream exhaust sensor <NUM> (or as an alternative thereto), the flow mixer <NUM> may be positioned within the mixing conduit <NUM> (e.g., at a location between the upstream and downstream ends <NUM>, <NUM> of the mixing conduit <NUM>) extending between the DOC system <NUM> and the SCR system <NUM>, such as at the location indicated by dashed lines 300A in <FIG>. In such an embodiment, the flow mixer <NUM> may be used to impart spiraling flow trajectories to the reductant/exhaust flow expelled from the DOC system <NUM> to facilitate proper mixing of the reductant and engine exhaust prior to such flow being directed into the SCR system <NUM>.

It should additionally be appreciated that, throughout the description, "about" is intended to mean within <NUM>% of the associated value(s).

Claim 1:
An exhaust treatment system (<NUM>) for a work vehicle (<NUM>), the system (<NUM>) including a selective catalytic reduction (SCR) system (<NUM>) configured to react a mixture of exhaust reductant and engine exhaust with a catalyst to generate a treated exhaust flow, the SCR system (<NUM>) including an SCR outlet (<NUM>) for expelling the treated exhaust flow therefrom, the system (<NUM>) further including a flow conduit (<NUM>) in fluid communication with the SCR outlet (<NUM>) for receiving the treated exhaust flow expelled from the SCR system (<NUM>), and an exhaust sensor (<NUM>) positioned within the flow conduit (<NUM>) downstream of the SCR outlet (<NUM>), the exhaust sensor (<NUM>) being configured to detect an amount of an emission gas present in the treated exhaust flow, the system (<NUM>) being characterized by:
a flow mixer (<NUM>) positioned upstream of the exhaust sensor (<NUM>), the flow mixer (<NUM>) comprising:
an end wall (<NUM>) defining sector openings (<NUM>) extending in a circumferential direction (CD1) of the flow mixer (<NUM>) between a first sector side (<NUM>) and a second sector side (<NUM>) and in a radial direction (R1) of the flow mixer (<NUM>) between a radially inner sector end (<NUM>) and a radially outer sector end (<NUM>); and
a plurality of swirler vanes (<NUM>), each of the plurality of swirler vanes (<NUM>) extending in the circumferential direction (CD1) from the first sector side (<NUM>) of a respective one of the sector openings (<NUM>) and in the radial direction (R1) between a radially inner vane end (<NUM>) and a radially outer vane end (<NUM>), the radially outer vane end (<NUM>) of each of the plurality of swirler vanes (<NUM>) being spaced apart in the radial direction (R1) from the radially outer sector end (<NUM>) of the respective one of the sector openings (<NUM>),
wherein the plurality of swirler vanes (<NUM>) is configured to impart a spiraling flow trajectory to the treated exhaust flow flowing from the SCR to the exhaust sensor (<NUM>).