Dispersion plate

Abstract

This dispersion plate (10) is provided with a first blade (21), a second blade (22), and a third blade (23) that are disposed at intervals in the circumferential direction of an exhaust passage. Each of the first blade (21), the second blade (22), and the third blade (23) extends from the inner peripheral surface side of an exhaust passage-forming member toward the center of the exhaust passage. Each of the first blade (21), the second blade (22), and the third blade (23) includes an inclined piece part (210, 220, 230) inclined at a first angle (θ1) in the swirling direction of exhaust gas. The tip part side of the inclined piece part (220) of the second blade (22) is bent at a second angle (θ2) toward the downstream side of the exhaust passage so as to be oriented toward the downstream side of the exhaust passage and toward the center of the exhaust passage. The tip part side of the inclined piece part (230) of the third blade (23) is bent at a third angle (θ3) so as to be oriented toward the downstream side of the exhaust passage and toward the center of the exhaust passage. The third angle (θ3) is greater than the second angle (θ2).

Description

Dispersion plate

[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.

[0002] Exhaust gases emitted from internal combustion engines such as diesel engines contain 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 an 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 ammonia (NH ３ The nitrogen oxides in the exhaust gas react with ammonia in the catalyst and are reduced and purified.

[0004] As a dispersion plate for dispersing urea water introduced into an exhaust path, Japanese Patent Application Laid-Open No. 2014-163232 (Patent Document 1) discloses a configuration in which a plurality of blades are provided extending from the outer periphery of a cylinder toward the center, and shielding plates are provided at intervals relative to the plurality of blades in the axial direction of the cylinder, and a passage opening formed in the center of the cylinder is covered by the plurality of shielding plates by being surrounded by the tips of the plurality 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.

[0006] JP 2014-163232 A

[0007] However, the shielding plate described in Patent Document 1 is configured by bending a plate-like member parallel to a plane perpendicular to the axial direction of the cylinder toward the center of the cylinder so as to move toward the downstream side of the cylinder axis. 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 quickly leave the shielding plate, and a urea deposit is formed 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, 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.

[0009] The dispersion plate of the present disclosure is disposed within 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 first, second, and third blades spaced apart in the circumferential direction of the exhaust path to swirl the exhaust gas flowing through the exhaust path. Each of the first, second, and third blades extends from an inner circumferential surface of the exhaust path forming member toward the center of the exhaust path when viewed axially of the exhaust path forming member. Each of the first, second, and third blades includes an inclined piece that is inclined at a first angle in the swirling direction of the exhaust gas. The tip end of the inclined piece 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. The tip end side of the inclined piece of the third blade is bent at a third angle so as to bend 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] According to the above configuration, the tip of the inclined piece of the first blade is spaced apart in the axial direction from the tip of the inclined piece of the second blade and the tip of the inclined piece of the third blade. This prevents droplets that bounce off the inclined piece of the first blade from adhering to the inclined pieces of the second and third blades located downstream. Furthermore, the inclination of the inclined piece of each blade prevents droplets from accumulating on the inclined piece, thereby preventing deposits from accumulating on each blade.

[0011] According to the present disclosure, it is possible to provide a dispersion plate that can suppress the accumulation of deposits.

[0012] Fig. 1 is a schematic cross-sectional view of an exhaust purification system according to embodiment 1. Fig. 2 is a perspective view of a dispersion device according to embodiment 1. Fig. 3 is a side view of a dispersion plate according to embodiment 1. Fig. 4 is a perspective view of a dispersion device showing how exhaust gas is swirled by the dispersion plate according to embodiment 1. Fig. 5 is a side view of a dispersion device showing how exhaust gas is dispersed by the dispersion plate according to embodiment 1. Fig. 6 is a schematic cross-sectional view of an exhaust purification system according to embodiment 2.

[0013] 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 numerals in the drawings, and the description thereof will not be repeated.

[0014] (Embodiment 1) Fig. 1 is a schematic cross-sectional view of an exhaust gas purification system according to embodiment 1. With reference to Fig. 1, an exhaust gas purification system 1 according to the embodiment will be described.

[0015] The exhaust gas purification system 1 shown in Fig. 1 is for purifying exhaust gas emitted from an internal combustion engine of an automobile. The exhaust gas purification system 1 includes an exhaust path forming member 2, an injection device 4, a catalyst 7, and a dispersion device 10.

[0016] The exhaust path forming member 2 defines an exhaust path through which exhaust gas emitted 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.

[0017] The first portion 2A is located upstream of the injector 4. The second portion 2B is bent and extends from the first portion 2A. The third portion 2C is configured coaxially with the second portion 2B and has an inner diameter larger than those of the first portion 2A and the second portion 2B.

[0018] 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 thermally decomposed by the heat of the exhaust gas to generate ammonia, and the ammonia thus generated functions as a reducing agent.

[0019] 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 so 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.

[0020] The dispersion device 10 is disposed in the second portion 2B. The dispersion device 10 is disposed in the exhaust path downstream of the injector 4 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.

[0021] The catalyst 7 is housed in the third portion 2C. Ｘ The catalyst 7 is an SCR type catalyst that reduces NOx contained in the exhaust gas into nitrogen and water by the reduction action of ammonia described above occurring in the catalyst 7.

[0022] Fig. 2 is a perspective view of the dispersing device according to embodiment 1. The detailed structure of the dispersing device 10 will be described with reference to Fig. 2 .

[0023] As shown in FIG. 2 , the dispersion device 10 includes a dispersion plate 20 and a cylindrical body 11 provided with a plurality of blade portions 12 .

[0024] The cylindrical body 11 extends along the exhaust path. More specifically, the cylindrical body 11 extends along the axial direction C of the exhaust path forming member 2 (more specifically, the axial direction C of the second portion 2B). The cylindrical body 11 has an upstream end 11a and a downstream end 11b. The plurality of blade portions 12 are bent from the downstream end 11b 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 plurality of blade portions 12 are arranged side by side in the circumferential direction of the cylindrical body 11. The plurality of blade portions 12 are bent so that their tip portions, located toward the center of the exhaust path, are more toward the upstream side of the exhaust path than their base portions, located toward the downstream end 11b. The plurality of blade portions 12 are inclined at a predetermined angle around an imaginary line extending radially of the cylindrical body 11 as a rotation axis.

[0025] 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 through the exhaust path (in the second portion 2B). The first blade 21, the second blade 22, and the third blade 23 are arranged side by side in this order along the swirling direction. In this embodiment, the swirling direction is clockwise, but it may also be counterclockwise. The first blade 21, the second blade 22, and the third blade 23 extend from the inner circumferential surface of the exhaust path forming member 2 toward the center of the exhaust path when viewed from the direction of axis C.

[0026] 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 circumferential surface 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 rotation 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 an imaginary plane perpendicular to the axis C of the exhaust path. The first angle θ1 is the smaller of the angles at which the inclined piece portion 210 intersects with the imaginary plane. The first angle θ1 is, for example, greater than or equal to 20 degrees and less than or equal to 30 degrees.

[0027] The fixed piece portion 215 is connected to the 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 it to the upstream end portion 11 a of the cylindrical body 11.

[0028] 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 circumferential surface 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 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 in the exhaust path than the second end portion 220b, and the inclined piece portion 220 is inclined so that it intersects with an imaginary plane perpendicular to the axial C direction of the exhaust path.

[0029] The fixed piece portion 225 is connected to the 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 it to the upstream end portion 11 a of the cylindrical body 11.

[0030] 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 closer to the base of the inclined piece portion 210. The first portion 221 connects the fixing piece portion 225 and the second portion 222. The inclined piece portion 220 is inclined at the first angle θ1 at the first portion 221.

[0031] 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 bend toward the downstream side of the exhaust path as it approaches the center of the exhaust path. The second portion 222 is mountain-folded.

[0032] 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, equal to or greater than 5 degrees and equal to or less than 15 degrees.

[0033] The third blade 23 includes an inclined piece 230 and a fixed piece 235. The inclined piece 230 extends from the inner circumferential surface of the exhaust path forming member 2 toward the center of the exhaust path. Like the inclined piece 210 described above, the inclined piece 230 is inclined at a first angle θ1 in the rotation direction. That is, the inclined piece 230 is inclined so that the first end 230a is located more upstream in the exhaust path than the second end 230b, and the inclined piece 230 is inclined so that it intersects with an imaginary plane perpendicular to the axial C direction of the exhaust path.

[0034] The fixed piece portion 235 is connected to the 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 it to the upstream end portion 11 a of the cylindrical body 11.

[0035] 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 base side of the inclined piece portion 230. The first portion 231 connects the fixing piece portion 235 and the second portion 232. The inclined piece portion 230 is inclined at the first angle θ1 at the first portion 231.

[0036] 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 bend toward the downstream side of the exhaust path as it approaches the center of the exhaust path. The second portion 232 is mountain-folded.

[0037] The third angle θ3 is the smaller of the angles at which the second portion 232 and the first portion 231 intersect. The third angle θ3 is larger than the second angle θ2. The third angle θ3 is, for example, equal to or greater than 20 degrees and equal to or less than 35 degrees.

[0038] Fig. 3 is a side view of the dispersion plate according to embodiment 1. For convenience, the cylindrical body 11 is shown by a dashed line in Fig. 3.

[0039] 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.

[0040] 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 part 2B).

[0041] 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 part 2B).

[0042] 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.

[0043] As shown in Figure 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.

[0044] In this case, when the reducing agent injected from the injector 4 collides with the inclined pieces 210, 220, and 230, the reducing agent droplets move on the inclined pieces 210, 220, and 230 along the swirling direction. That is, the droplets move from the first ends 210a, 220a, and 230a toward the second ends 210b, 220b, and 230b. This shortens the distance the droplets travel compared to when the droplets move along the longitudinal direction of each inclined piece 210, 220, and 230 toward the center of the exhaust path. As a result, the droplets are more likely to leave the inclined pieces 210, 220, and 230, and retention of the droplets on the inclined pieces 210, 220, and 230 can be suppressed.

[0045] Furthermore, by inclining each of the inclined piece portions 210, 220, and 230 as described above, droplets that bounce off the inclined piece portion 210 can be prevented from hitting the inclined piece portions 220 and 230 located downstream. Also, droplets that bounce off the inclined piece portion 220 can be prevented from hitting the inclined piece portion 230 located downstream. As a result, droplets can be prevented from accumulating on the inclined piece portions 220 and 230 located downstream. By setting the range of the first angle θ1 as described above, these effects can be preferably achieved.

[0046] 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.

[0047] As shown in Figure 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 (upstream main surface) of each inclined piece portion 210, 220, 230 but also on the back surface (downstream main surface) of each inclined piece portion 210, 220, 230. This makes each inclined piece portion 210, 220, 230 more susceptible to heating by the exhaust gas, facilitating evaporation of droplets adhering to the front surface. This also prevents droplets from accumulating on the inclined piece portions 210, 220, 230.

[0048] 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, which is the third blade from the upstream side, 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.

[0049] When the second angle θ2 and the third angle θ3 are equal in bending angle, the distance between the tip of the inclined piece 210 of the first blade 21, the tip of the inclined piece 220 of the second blade 22, and the tip of the inclined piece 230 of the third blade 23 becomes small in the axial direction C. In such a case, droplets that bounce off the inclined piece 210 of the first blade 21 located most upstream are likely to hit the tip of the inclined piece 220 of the second blade 22 and the tip of the inclined piece 230 of the third blade 23.

[0050] In this embodiment, the third angle θ3 is larger than the second angle θ2. Therefore, the distance between the tip of the inclined piece 210, the tip of the inclined piece 220, and the tip of the inclined piece 230 is increased in the axial direction C. This prevents droplets that bounce off the inclined piece 210 from adhering to the inclined piece portions 220 and 230 located downstream.

[0051] If the range of the second angle θ2 and the range of the third angle θ3 are below the above-mentioned ranges, the tips of the inclined piece portions 210, 220, and 230 become too close to each other, causing droplets to gather between these tips, increasing the vapor pressure. In this case, the droplets do not evaporate easily, making it easier for urea deposits to build up.

[0052] Furthermore, when the range of the second angle θ2 and the range of the third angle θ3 exceed the above-mentioned ranges, droplets that collide with the inclined piece portions 220, 230 bounce upstream or form a liquid film that moves along the longitudinal direction of each inclined piece portion 220, 230 toward the center of the exhaust path. When the liquid film moves in the longitudinal direction, it is difficult for the droplets to leave the inclined piece portions 220, 230. Furthermore, as droplets gather in the center of the exhaust path, the vapor pressure increases locally near the center, making it difficult for the droplets to evaporate. Furthermore, as droplets gather in the center and evaporate there, the temperature near the center decreases, making it difficult for the droplets to evaporate. As a result, urea deposits are more likely to accumulate on the inclined piece portions 210, 220, 230.

[0053] 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, it is possible to maintain an appropriate 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. Furthermore, by setting the lengths 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, it is possible to maintain an appropriate distance between the inclined piece portions 210, 220, and 230. As a result, it is possible to prevent droplets from remaining on the inclined piece portions 210, 220, and 230 and to prevent urea deposits from accumulating.

[0054] As described above, the dispersion plate 20 according to this embodiment can prevent droplets from accumulating on the inclined piece portions 210, 220, and 230, thereby preventing urea deposits from accumulating on the inclined piece portions 210, 220, and 230.

[0055] (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.

[0056] 6, the exhaust gas purification system 1A according to the second embodiment differs from the exhaust gas purification system 1 according to the first embodiment in the configuration of a dispersion device 10A. The other configurations are substantially the same.

[0057] Unlike the first embodiment, the dispersion device 10A does not include a cylindrical body 11 having a plurality of blade portions 12, but is instead configured with a dispersion plate 20. The dispersion plate 20 is fixed to the inner circumferential surface of the exhaust path forming member 2. Specifically, the first blade 21 is fixed to the inner circumferential surface of the second portion 2B by a fixing piece portion 215. The second blade 22 is fixed to the inner circumferential surface of the second portion 2B by a fixing piece portion 225. The third blade 23 is fixed to the inner circumferential surface of the second portion 2B by a fixing piece portion 235.

[0058] Even with the above configuration, substantially the same effects as in embodiment 1 can be obtained. In particular, embodiment 2 is effective when the spray of reducing agent injected from injector 4 always hits first blade 21, second blade 22, and third blade 23, regardless of the driving conditions of the vehicle. Under such circumstances, even if cylindrical body 11 is omitted, first blade 21, second blade 22, and third blade 23 can sufficiently disperse the reducing agent.

[0059] (Other Modifications) In the first and second embodiments described above, 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 this is not limiting. The first blade 21, the second blade 22, and the third blade 23 may also be arranged counterclockwise.

[0060] In the above-described 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 inside the exhaust path forming member 2, and are fixed to the inner peripheral surface of the exhaust path forming member 2, but the present invention is not limited to this. The first blade 21, the second blade 22, and the third blade 23 may be fixed to a fixture provided inside the exhaust path forming member 2, or to a fixture provided on the cylindrical body 11 arranged inside the exhaust path forming member 2. The fixture may extend toward the center of the exhaust path.

[0061] 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 injection device 4 hits them.

[0062] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims.

[0063] 1, 1A exhaust purification system, 2 exhaust path forming member, 2A first part, 2B second part, 2C third part, 4 injection device, 5 flow path member, 7 catalyst, 10, 10A dispersion device, 11 cylinder, 11a upstream end, 11b downstream end, 12 blade portion, 20 dispersion plate, 21 first blade, 22 second blade, 23 third blade, 210 inclined piece portion, 210a first end, 210b second end, 215 fixed piece portion, 220 inclined piece portion, 220a first end, 220b second end, 221 first part, 222 second part, 225 fixed piece portion, 230 inclined piece portion, 230a first end, 230b second end, 235 fixed piece portion, C axial direction.

Claims

1. A dispersion plate disposed within a cylindrical exhaust path forming member that defines an exhaust path through which exhaust gas flows, dispersing a reducing agent supplied to the upstream side of the exhaust path toward the downstream side, the dispersion plate comprising 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 extending 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 including an inclined piece portion inclined at a first angle in the swirling direction of the exhaust gas, and a 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, A dispersion plate, wherein a tip side of the inclined piece portion of the third blade is bent at a third angle so as to move toward the downstream side of the exhaust path as it moves toward the center of the exhaust path, the third angle being greater than the second angle.

2. The dispersion plate according to 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 according to 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. A dispersion plate as described in claim 1, wherein the inclined piece portion of the first blade is located further upstream of the exhaust path than the inclined piece portion of the second blade, and the inclined piece portion of the second blade is located further upstream of the exhaust path than the inclined piece portion of the third blade.

6. The dispersion plate described in claim 1, wherein 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 circumferential end side of the exhaust path and a second end portion located on the other circumferential end side 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 is 10% or more and 20% or less of an inner diameter of the exhaust path forming member, and 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 is 10% or more and 20% or less of an inner diameter of the exhaust path forming member.

7. A dispersion plate according to any one of claims 1 to 6, 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. A dispersion plate as described in any one of claims 1 to 6, wherein each of the first blade, the second blade, and the third blade is fixed to a cylinder arranged within the exhaust path forming member.

9. A dispersion plate as described in any one of claims 1 to 6, 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 to a mounting fixture provided on a cylinder disposed within the exhaust path forming member.

Images