Dispersion plate

Abstract

To provide a dispersion plate which can suppress the accumulation of deposits.SOLUTION: A dispersion plate 10 comprises a first blade 21, a second blade 22 and a third blade 23 which are arranged with intervals in a circumferential direction of an exhaust path. The first blade 21, the second blade 22 and the third blade 23 extend toward a center side of the exhaust path from an internal peripheral side of an exhaust path forming member, and the first blade 21, the second blade 22 and the third blade 23 include inclination piece parts 210, 220 and 230, respectively, which are inclined by a first angle θ1 in a turning direction of an exhaust gas. A tip part side of the inclination piece part 220 possessed by the second blade 22 is bent by a second angle θ2 so as to progress toward a downstream side of the exhaust path as progressing toward a center of the exhaust path, and a tip part side of the inclination piece part 230 possessed by the third blade 23 is bent by a third angle θ3 so as to progress toward the downstream side of the exhaust path as progressing toward the center of the exhaust path, and the third angle sit 3 is larger than the second angle θ2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a dispersion plate that disperses a reducing agent supplied to the upstream side of an exhaust flow passage toward the downstream side. [Background technology]

[0002] Exhaust gas from internal combustion engines such as diesel engines contains nitrogen oxides (NO X A known exhaust gas purification system for purifying such exhaust gases is one that has a selective catalytic reduction (SCR) catalyst installed in the exhaust gas passage and injects urea water, a reducing agent, into the exhaust gas upstream of the catalyst.

[0003] The urea solution injected into the exhaust gas is hydrolyzed by the heat of the exhaust gas, and the ammonia (NH3) produced by the hydrolysis of the urea solution is supplied to the catalyst together with the exhaust gas. The nitrogen oxides in the exhaust gas react with the ammonia in the catalyst and are reduced and purified.

[0004] As a dispersion plate for dispersing urea water introduced into an exhaust path, JP 2014-163232 A (Patent Document 1) discloses a configuration in which a number of blades are provided extending from the outer periphery of a cylinder toward the center, and shielding plates are provided at intervals from the number of blades in the axial direction of the cylinder, and a passage opening formed in the center of the cylinder is covered by the number of shielding plates by being surrounded by the tips of the number of blades.

[0005] By covering the passage opening with the shielding plate, the reducing agent attempting to pass through the passage opening can be made to collide with the shielding plate, thereby improving the dispersion of the reducing agent. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-163232 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the shielding plate described in Patent Document 1 is configured by bending a plate-shaped member parallel to a plane perpendicular to the axial direction of the cylinder so as to move toward the downstream side of the cylinder axis as it moves toward the center of the cylinder. Therefore, when the reducing agent collides, the droplets adhering to the shielding plate move toward the tip side of the shielding plate located at the center of the cylinder. As a result, the droplets (liquid film) cannot immediately leave the shielding plate, and a urea deposit is generated on the shielding plate. As the internal combustion engine continues to operate, the urea deposit grows and accumulates on the shielding plate. The deposit absorbs the urea introduced into the exhaust path, reducing the dispersibility of the reducing agent. As a result, the amount of nitrogen oxides (NO X ) purification rate decreases.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a dispersion plate that can suppress the accumulation of deposits. [Means for solving the problem]

[0009] The dispersion plate of the present disclosure is disposed in a cylindrical exhaust path forming member that defines an exhaust path through which exhaust gas flows, and disperses a reducing agent supplied to the upstream side of the exhaust path toward the downstream side. The dispersion plate includes a first blade, a second blade, and a third blade that are disposed at intervals in the circumferential direction of the exhaust path so as to swirl the exhaust gas flowing through the exhaust path. Each of the first blade, the second blade, and the third blade extends from the inner peripheral surface side of the exhaust path forming member toward the center side of the exhaust path when viewed from the axial direction of the exhaust path forming member. Each of the first blade, the second blade, and the third blade includes an inclined piece portion that is inclined at a first angle in the swirling direction of the exhaust gas. The tip side of the inclined piece portion of the second blade is bent at a second angle so as to move toward the downstream side of the exhaust path as it moves toward the center of the exhaust path. The tip end side of the inclined piece of the third blade is bent at a third angle toward the downstream side of the exhaust path as it approaches the center of the exhaust path. The third angle is greater than the second angle.

[0010] In the dispersion plate according to the present disclosure, the first angle may be greater than or equal to 20 degrees and less than or equal to 30 degrees.

[0011] In the dispersion plate according to the present disclosure, the second angle may be greater than or equal to 5 degrees and less than or equal to 15 degrees.

[0012] In the dispersion plate according to the present disclosure, the third angle may be equal to or greater than 20 degrees and equal to or less than 35 degrees.

[0013] In the dispersion plate according to the present disclosure, the inclined piece portion of the first blade may be located upstream of the exhaust path relative to the inclined piece portion of the second blade. The inclined piece portion of the second blade may be located upstream of the exhaust path relative to the inclined piece portion of the third blade.

[0014] In the dispersion plate according to the present disclosure, the inclined piece portion of each of the first blade, the second blade, and the third blade may include a first end portion located at one end side of the circumferential direction of the exhaust path, and a second end portion located at the other end side of the circumferential direction of the exhaust path. A length along the axial direction between the first end portion of the inclined piece portion of the first blade and the first end portion of the inclined piece portion of the second blade may be 10% to 20% of an inner diameter of the exhaust path forming member. A length along the axial direction between the first end portion of the inclined piece portion of the second blade and the first end portion of the inclined piece portion of the third blade may be 10% to 20% of an inner diameter of the exhaust path forming member.

[0015] In the dispersion plate according to the present disclosure, each of the first blade, the second blade, and the third blade may be fixed to the inner circumferential surface of the exhaust path forming member.

[0016] In the dispersion plate according to the present disclosure, each of the first blade, the second blade, and the third blade may be fixed to a cylinder disposed within the exhaust path forming member.

[0017] In the dispersion plate based on the present disclosure described above, each of the first blade, the second blade, and the third blade may be fixed to a mounting fixture provided within the exhaust path forming member, or to a mounting fixture provided on a cylinder disposed within the exhaust path forming member. Effect of the Invention

[0018] According to the present disclosure, it is possible to provide a dispersion plate capable of suppressing the accumulation of deposits. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic cross-sectional view of an exhaust purification system according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of a dispersion device according to the first embodiment. [Diagram 3]FIG. 2 is a side view of the dispersion plate according to the first embodiment. [Figure 4] 3 is a perspective view of the dispersion device, showing how exhaust gas is swirled by the dispersion plate according to the first embodiment. FIG. [Diagram 5] 3 is a side view of the dispersion device, illustrating how exhaust gas is dispersed by the dispersion plate according to the first embodiment. FIG. [Figure 6] FIG. 11 is a schematic cross-sectional view of an exhaust purification system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference characters in the drawings, and the description thereof will not be repeated.

[0021] (Embodiment 1) Fig. 1 is a schematic cross-sectional view of an exhaust purification system according to embodiment 1. With reference to Fig. 1, an exhaust purification system 1 according to the embodiment will be described.

[0022] 1 is for purifying exhaust gas emitted from an internal combustion engine of an automobile. The exhaust purification system 1 includes an exhaust path forming member 2, an injector 4, a catalyst 7, and a dispersion device 10.

[0023] The exhaust path forming member 2 defines an exhaust path through which exhaust gas discharged from an internal combustion engine flows. The exhaust path forming member 2 has a cylindrical shape. The exhaust path forming member 2 includes a first portion 2A, a second portion 2B, and a third portion 2C. The first portion 2A, the second portion 2B, and the third portion 2C are arranged in this order from the upstream side to the downstream side of the exhaust path, and all of them are cylindrical.

[0024] The first portion 2A is located upstream of the injection device 4. The second portion 2B is bent and extended from the first portion 2A. The third portion 2C is configured coaxially with the second portion 2B, and is formed to have an inner diameter larger than the first portion 2A and the second portion 2B.

[0025] The injector 4 injects a urea aqueous solution (urea water) as a reducing agent into the exhaust path forming member 2 (more specifically, the second portion 2B). Specifically, the injector 4 injects the urea water upstream of the dispersion device 10. The urea water injected into the exhaust gas is hydrolyzed and pyrolyzed by the heat of the exhaust gas to generate ammonia, and the ammonia thus generated functions as a reducing agent.

[0026] The injection device 4 includes a flow path member 5 that defines an introduction path for the urea water. The flow path member 5 has a cylindrical shape. The flow path member 5 is configured, for example, coaxially with the second portion 2B. The flow path member 5 may be provided such that the inner diameter of the flow path gradually increases toward the exhaust flow path. The flow path member 5 is provided so as to penetrate the first portion 2A.

[0027] The dispersion device 10 is disposed in the second portion 2B. The dispersion device 10 is disposed downstream of the injector 4 in the exhaust path and upstream of the catalyst 7. The dispersion device 10 disperses the reducing agent supplied to its upstream side in the exhaust path toward the downstream side.

[0028] The catalyst 7 is housed in the third portion 2C. The catalyst 7 is X The catalyst 7 is an SCR catalyst that reduces NOx contained in the exhaust gas into nitrogen and water as the above-mentioned ammonia reduction action occurs in the catalyst 7.

[0029] Fig. 2 is a perspective view of the dispersion device according to embodiment 1. The detailed structure of the dispersion device 10 will be described with reference to Fig. 2.

[0030] As shown in FIG. 2, the dispersion device 10 includes a dispersion plate 20 and a cylindrical body 11 on which a plurality of blade portions 12 are provided.

[0031] The cylindrical body 11 extends along the exhaust path. More specifically, the cylindrical body 11 extends along the axial C direction of the exhaust path forming member 2 (more specifically, the axial C direction of the second portion 2B). The cylindrical body 11 has an upstream end 11a and a downstream end 11b. The blades 12 are bent from the downstream end 11b side toward the center of the cylindrical body 11. The center of the cylindrical body 11 is located at the center of the exhaust path in the second portion 2B. The blades 12 are arranged side by side in the circumferential direction of the cylindrical body 11. The blades 12 are bent so that the tip portion located at the center side of the exhaust path is closer to the upstream side of the exhaust path than the base portion located at the downstream end 11b side. The blades 12 are inclined at a predetermined angle with a virtual line extending in the radial direction of the cylindrical body 11 as the rotation axis.

[0032] The dispersion plate 20 includes a first blade 21, a second blade 22, and a third blade 23. The first blade 21, the second blade 22, and the third blade 23 are arranged at intervals in the circumferential direction of the exhaust path so as to swirl the exhaust gas flowing in the exhaust path (in the second portion 2B). The first blade 21, the second blade 22, and the third blade 23 are arranged in this order along the swirling direction. In this embodiment, the swirling direction is clockwise, but it may be counterclockwise. The first blade 21, the second blade 22, and the third blade 23 extend from the inner peripheral surface side of the exhaust path forming member 2 toward the center side of the exhaust path when viewed from the axis C direction.

[0033] The first blade 21 includes an inclined piece portion 210 and a fixed piece portion 215. The inclined piece portion 210 extends from the inner peripheral surface side of the exhaust path forming member 2 toward the center of the exhaust path. The inclined piece portion 210 has a first end portion 210a and a second end portion 210b in the circumferential direction of the exhaust path. The inclined piece portion 210 is inclined at a first angle θ1 in the turning direction. Specifically, the inclined piece portion 210 is inclined so that the first end portion 210a is located upstream of the exhaust path relative to the second end portion 210b, and the inclined piece portion 210 is inclined so as to intersect with a virtual plane perpendicular to the axial C direction of the exhaust path. The first angle θ1 is the smaller angle of the angles at which the inclined piece portion 210 intersects with the virtual plane. The first angle θ1 is, for example, 20 degrees or more and 30 degrees or less.

[0034] The fixed piece portion 215 is connected to a base portion of the inclined piece portion 210. The fixed piece portion 215 fixes the inclined piece portion 210 to the inner circumferential surface of the cylindrical body 11. The fixed piece portion 215 may fix the inclined piece portion 210 to the outer circumferential surface of the cylindrical body 11, or may fix the inclined piece portion 210 to the upstream end portion 11a of the cylindrical body 11.

[0035] The second blade 22 includes an inclined piece portion 220 and a fixed piece portion 225. The inclined piece portion 220 extends from the inner peripheral surface side of the exhaust path forming member 2 toward the center of the exhaust path. Like the inclined piece portion 210 described above, the inclined piece portion 220 is also inclined at a first angle θ1 in the rotation direction. That is, the inclined piece portion 220 is inclined so that the first end portion 220a is located more upstream of the exhaust path than the second end portion 220b, and the inclined piece portion 220 is inclined so as to intersect with an imaginary plane perpendicular to the axial C direction of the exhaust path.

[0036] The fixed piece portion 225 is connected to a base portion of the inclined piece portion 220. The fixed piece portion 225 fixes the inclined piece portion 220 to the inner circumferential surface of the cylindrical body 11. The fixed piece portion 225 may fix the inclined piece portion 220 to the outer circumferential surface of the cylindrical body 11, or may fix the inclined piece portion 220 to the upstream end portion 11a of the cylindrical body 11.

[0037] The inclined piece portion 220 has a first portion 221 and a second portion 222. The first portion 221 is located closer to the inner circumferential surface of the exhaust path forming member 2 than the second portion 222. The first portion 221 is located on the root side of the inclined piece portion 210. The first portion 221 connects the fixed piece portion 225 and the second portion 222. The inclined piece portion 220 is inclined at the first angle θ1 in the first portion 221.

[0038] The second portion 222 is located on the tip end side of the inclined piece portion 220. The second portion 222 is located closer to the center of the exhaust path than the first portion 221. The second portion 222 is bent at a second angle θ2 so as to move toward the downstream side of the exhaust path as it moves toward the center of the exhaust path. The second portion 222 is bent in a mountain shape.

[0039] The second angle θ2 is the smaller of the angles at which the second portion 222 and the first portion 221 intersect. The second angle θ2 is smaller than the first angle θ1. The second angle θ2 is, for example, not less than 5 degrees and not more than 15 degrees.

[0040] The third blade 23 includes an inclined piece portion 230 and a fixed piece portion 235. The inclined piece portion 230 extends from the inner peripheral surface side of the exhaust path forming member 2 toward the center of the exhaust path. Like the inclined piece portion 210 described above, the inclined piece portion 230 is also inclined at a first angle θ1 in the rotation direction. That is, the inclined piece portion 230 is inclined so that the first end portion 230a is located more upstream of the exhaust path than the second end portion 230b, and the inclined piece portion 230 is inclined so as to intersect with an imaginary plane perpendicular to the axial C direction of the exhaust path.

[0041] The fixed piece portion 235 is connected to a base portion of the inclined piece portion 230. The fixed piece portion 235 fixes the inclined piece portion 230 to the inner circumferential surface of the cylindrical body 11. The fixed piece portion 235 may fix the inclined piece portion 230 to the outer circumferential surface of the cylindrical body 11, or may fix the inclined piece portion 230 to the upstream end portion 11a of the cylindrical body 11.

[0042] The inclined piece portion 230 has a first portion 231 and a second portion 232. The first portion 231 is located closer to the inner circumferential surface of the exhaust path forming member 2 than the second portion 232. The first portion 231 is located on the root side of the inclined piece portion 230. The first portion 231 connects the fixed piece portion 235 and the second portion 232. The inclined piece portion 230 is inclined at the first angle θ1 in the first portion 231.

[0043] The second portion 232 is located on the tip end side of the inclined piece portion 230. The second portion 232 is located closer to the center of the exhaust path than the first portion 231. The second portion 232 is bent at a third angle θ3 so as to move toward the downstream side of the exhaust path as it moves toward the center of the exhaust path. The second portion 232 is bent in a mountain shape.

[0044] The third angle θ3 is the smaller angle between the second portion 232 and the first portion 231. The third angle θ3 is greater than the second angle θ2. The third angle θ3 is, for example, greater than or equal to 20 degrees and less than or equal to 35 degrees.

[0045] Fig. 3 is a side view of the dispersion plate according to the embodiment 1. In Fig. 3, for the sake of convenience, the cylindrical body 11 is indicated by a dashed line.

[0046] 3, the inclined piece portion 210 of the first blade 21 is located further upstream in the exhaust path than the inclined piece portion 220 of the second blade 22. The inclined piece portion 220 of the second blade 22 is located further upstream in the exhaust path than the inclined piece portion 230 of the third blade 23.

[0047] The length L1 along the axial direction between the first end 210a of the inclined piece portion 210 of the first blade 21 and the first end 220a of the inclined piece portion 220 of the second blade 22 is 10% or more and 20% or less of the inner diameter of the exhaust path forming member 2 (the inner diameter of the second portion 2B).

[0048] The length along the axial direction between the first end 220a of the inclined piece portion 220 of the second blade 22 and the first end of the inclined piece portion 230 of the third blade 23 is 10% or more and 20% or less of the inner diameter of the exhaust path forming member 2 (the inner diameter of the second portion 2B).

[0049] 4 is a perspective view of the dispersion device, showing how exhaust gas is swirled by the dispersion plate according to embodiment 1. The swirling of exhaust gas will be described with reference to FIG.

[0050] As shown in FIG. 4, the inclined piece portion 210 of the first blade 21, the inclined piece portion 220 of the second blade 22, and the inclined piece portion 230 of the third blade 23 are inclined at the first angle θ1 as described above, thereby allowing the exhaust gas to swirl as shown by the arrow AR1.

[0051] At this time, when the reducing agent injected from the injection device 4 collides with the inclined piece portions 210, 220, 230, the reducing agent droplets move on the inclined piece portions 210, 220, 230 along the swirling direction. That is, the droplets move from the first end portions 210a, 220a, 230a toward the second end portions 210b, 220b, 230b. Therefore, the moving distance of the droplets can be made shorter than when the droplets move along the longitudinal direction of each inclined piece portion 210, 220, 230 toward the center of the exhaust path. As a result, the droplets are more likely to leave the inclined piece portions 210, 220, 230, and the droplets can be prevented from accumulating on the inclined piece portions 210, 220, 230.

[0052] Furthermore, by inclining each of the inclined piece portions 210, 220, 230 as described above, it is possible to prevent droplets that bounce off the inclined piece portion 210 from hitting the inclined piece portion 220, 230 located downstream. It is also possible to prevent droplets that bounce off the inclined piece portion 220 from hitting the inclined piece portion 230 located downstream. As a result, it is possible to prevent droplets from accumulating on the inclined piece portions 220, 230 located downstream. By setting the range of the first angle θ1 as described above, it is possible to preferably exhibit such effects.

[0053] FIG. 5 is a side view of the dispersion device, showing how exhaust gas is dispersed by the dispersion plate according to the first embodiment.

[0054] 5, when exhaust gas swirls as indicated by arrow AR1, a flow of exhaust gas as indicated by arrow AR2 occurs not only on the front surface side (upstream main surface side) of each inclined piece portion 210, 220, 230 but also on the back surface side (downstream main surface side) of each inclined piece portion 210, 220, 230. This makes each inclined piece portion 210, 220, 230 more likely to be heated by exhaust gas, and liquid droplets attached to the front surface tend to evaporate. This also makes it possible to prevent liquid droplets from accumulating on the inclined piece portions 210, 220, 230.

[0055] Furthermore, the tip side of the inclined piece portion 220 of the second blade 22, which is the second blade from the upstream side among the first blade 21, the second blade 22, and the third blade 23, is mountain-folded at a second angle θ2, and the tip side of the inclined piece portion 230 of the third blade 23, which is the third blade from the upstream side, is mountain-folded at a third angle θ3.

[0056] When the second angle θ2 and the third angle θ3 are equal in bending angle, the distance between the tip of the inclined piece portion 210 of the first blade 21, the tip of the inclined piece portion 220 of the second blade 22, and the tip of the inclined piece portion 230 of the third blade 23 becomes closer in the axial direction C. In such a case, the liquid droplets that bounce off the inclined piece portion 210 of the first blade 21 located most upstream are likely to hit the tip of the inclined piece portion 220 of the second blade 22 and the tip of the inclined piece portion 230 of the third blade 23.

[0057] Here, in this embodiment, the third angle θ3 is greater than the second angle θ2. Therefore, the tip of the inclined piece portion 210, the tip of the inclined piece portion 220, and the tip of the inclined piece portion 230 are spaced apart in the axial direction C. This makes it possible to prevent droplets that have bounced off the inclined piece portion 210 from adhering to the inclined piece portions 220 and 230 located downstream.

[0058] If the range of the second angle θ2 and the range of the third angle θ3 are below the above-mentioned ranges, the tip of the inclined piece portion 210, the tip of the inclined piece portion 220, and the tip of the inclined piece portion 230 will be too close to each other, and liquid droplets will gather between these tips, increasing the vapor pressure. In this case, the liquid droplets will not evaporate easily, and urea deposits will be easily accumulated.

[0059] Furthermore, when the range of the second angle θ2 and the range of the third angle θ3 exceed the above-mentioned ranges, the liquid droplets colliding with the inclined piece portions 220 and 230 bounce back to the upstream side or turn into a liquid film and move along the longitudinal direction of each of the inclined piece portions 220 and 230 so as to move toward the center of the exhaust path. When the liquid film moves toward the longitudinal direction, it is difficult to leave the inclined piece portions 220 and 230. Furthermore, when the liquid droplets gather at the center of the exhaust path, the vapor pressure increases locally near the center, making it difficult for the liquid droplets to evaporate. Furthermore, when the liquid droplets gather at the center and evaporate there, the temperature near the center decreases, making it difficult for the liquid droplets to evaporate. As a result, urea deposits are easily accumulated on the inclined piece portions 210, 220, and 230.

[0060] In this embodiment, by setting the range of the second angle θ2 and the range of the third angle θ3 within the above-mentioned ranges, the distance between the tip of the inclined piece portion 210, the tip of the inclined piece portion 220, and the tip of the inclined piece portion 230 can be appropriately maintained. Furthermore, by setting the lengths of L1 and L2 to be 10% or more and 20% or less of the inner diameter of the exhaust path forming member 2 (specifically, the second portion 2B) as described above, the distance between the inclined piece portions 210, 220, and 230 can also be appropriately maintained. As a result, it is possible to suppress the accumulation of urea deposits due to droplets staying on the inclined piece portions 210, 220, and 230.

[0061] As described above, in the dispersion plate 20 according to this embodiment, it is possible to prevent droplets from accumulating on the inclined pieces 210, 220, and 230, and therefore it is possible to prevent urea deposits from accumulating on the inclined pieces 210, 220, and 230.

[0062] (Embodiment 2) Fig. 6 is a schematic cross-sectional view of an exhaust purification system according to embodiment 2. For convenience, Fig. 6 shows the periphery of a dispersion device 10A in the exhaust purification system.

[0063] 6, an exhaust purification system 1A according to embodiment 2 differs from the exhaust purification system 1 according to embodiment 1 in the configuration of a dispersion device 10A. The other configurations are almost the same.

[0064] The dispersion device 10A does not include a cylindrical body 11 having a plurality of blade portions 12 as compared with the first embodiment, and is configured by a dispersion plate 20. The dispersion plate 20 is fixed to the inner peripheral surface of the exhaust path forming member 2. Specifically, the first blade 21 is fixed to the inner peripheral surface of the second portion 2B by a fixing piece portion 215. The second blade 22 is fixed to the inner peripheral surface of the second portion 2B by a fixing piece portion 225. The third blade 23 is fixed to the inner peripheral surface of the second portion 2B by a fixing piece portion 235.

[0065] Even when configured as described above, it is possible to obtain substantially the same effects as in embodiment 1. In particular, embodiment 2 is effective in cases where the spray of the reducing agent injected from the injector 4 always hits the first blade 21, the second blade 22, and the third blade 23, regardless of the driving conditions of the vehicle. Under such circumstances, even if the cylindrical body 11 is omitted, the reducing agent can be sufficiently dispersed by the first blade 21, the second blade 22, and the third blade 23.

[0066] (Other variations) In the above-mentioned first and second embodiments, the first blade 21, the second blade 22, and the third blade 23 are arranged clockwise from the upstream side so as to generate a clockwise swirling flow, but the present invention is not limited to this. The first blade 21, the second blade 22, and the third blade 23 may be arranged counterclockwise.

[0067] In the above-mentioned first and second embodiments, the first blade 21, the second blade 22, and the third blade 23 are fixed to the cylindrical body 11 arranged in the exhaust path forming member 2, and are fixed to the inner peripheral surface of the exhaust path forming member 2, but are not limited thereto. The first blade 21, the second blade 22, and the third blade 23 may be fixed to a fixture provided in the exhaust path forming member 2, or to a fixture provided on the cylindrical body 11 arranged in the exhaust path forming member 2. The fixture may extend toward the center of the exhaust path.

[0068] Furthermore, the first blade 21, the second blade 22, and the third blade 23 may be arranged inside an imaginary circle drawn within the exhaust path forming member 2 at a position 5 mm radially outward from the location where the reducing agent injected from the injector 4 hits them.

[0069] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0070] 1,1A exhaust purification system, 2 exhaust path forming member, 2A first portion, 2B second portion, 2C third portion, 4 injection device, 5 flow path member, 7 catalyst, 10,10A dispersion device, 11 cylinder, 11a upstream end portion, 11b downstream end portion, 12 blade portion, 20 dispersion plate, 21 first blade, 22 second blade, 23 third blade, 210 inclined piece portion, 210a first end portion, 210b second end portion, 215 fixed piece portion, 220 inclined piece portion, 220a first end portion, 220b second end portion, 221 first portion, 222 second portion, 225 fixed piece portion, 230 inclined piece portion, 230a first end portion, 230b second end portion, 235 fixed piece portion, C axial direction.

Claims

1. A dispersion plate that is disposed in a cylindrical exhaust path forming member that defines an exhaust path through which exhaust gas flows, and disperses a reducing agent supplied to an upstream side in the exhaust path toward a downstream side, a first blade, a second blade, and a third blade that are arranged at intervals in a circumferential direction of the exhaust path so as to swirl the exhaust gas flowing through the exhaust path; each of the first blade, the second blade, and the third blade extends from an inner circumferential surface side of the exhaust path forming member toward a center side of the exhaust path when viewed in an axial direction of the exhaust path forming member; Each of the first blade, the second blade, and the third blade includes an inclined piece portion inclined at a first angle to a swirling direction of the exhaust gas, a tip end side of the inclined piece portion of the second blade is bent at a second angle toward the downstream side of the exhaust path as it approaches the center of the exhaust path, a tip end side of the inclined piece portion of the third blade is bent at a third angle toward the downstream side of the exhaust path as it approaches the center of the exhaust path, The third angle is greater than the second angle.

2. The dispersion plate of claim 1 , wherein the first angle is greater than or equal to 20 degrees and less than or equal to 30 degrees.

3. The dispersion plate of claim 2 , wherein the second angle is greater than or equal to 5 degrees and less than or equal to 15 degrees.

4. The dispersion plate according to claim 3 , wherein the third angle is greater than or equal to 20 degrees and less than or equal to 35 degrees.

5. the inclined piece portion of the first blade is located on the upstream side of the exhaust path relative to the inclined piece portion of the second blade, The dispersion plate according to claim 1 , wherein the inclined piece portion of the second blade is located on the upstream side of the exhaust path relative to the inclined piece portion of the third blade.

6. the inclined piece portion of each of the first blade, the second blade, and the third blade includes a first end portion located on one end side of the circumferential direction of the exhaust path, and a second end portion located on the other end side of the circumferential direction of the exhaust path, a length along the axial direction between the first end of the inclined piece portion of the first blade and the first end of the inclined piece portion of the second blade is 10% or more and 20% or less of an inner diameter of the exhaust path forming member, 2. The dispersion plate according to claim 1, wherein a length along the axial direction between the first end of the inclined piece portion of the second blade and the first end of the inclined piece portion of the third blade is 10% or more and 20% or less of an inner diameter of the exhaust path forming member.

7. The dispersion plate according to claim 1 , wherein each of the first blade, the second blade, and the third blade is fixed to the inner circumferential surface of the exhaust path forming member.

8. The dispersion plate according to claim 1 , wherein each of the first blade, the second blade, and the third blade is fixed to a cylinder disposed within the exhaust path forming member.

9. 7. The dispersion plate according to claim 1, wherein each of the first blade, the second blade, and the third blade is fixed to a mounting fixture provided within the exhaust path forming member or a mounting fixture provided on a cylinder disposed within the exhaust path forming member.

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