JP2019120197A - Mixing device - Google Patents

Abstract

To favorably diffuse a reductant into exhaust emission.SOLUTION: A connecting part of a mixing device connects an upstream pipe and a downstream pipe, and makes exhaust emission from an internal combustion engine flow down. A injection part of the mixing device has a hole part formed at the connecting part in order to inject a reductant. The connecting part extends along a curved path, and has an upstream region and a downstream region as a flow passage of exhaust emission. The upstream region faces an upstream-side opening forming an end part of the upstream pipe, and the downstream region faces a downstream-side opening forming an end part of the downstream pipe. Then, the hole part of the injection part is located at a portion covering the downstream region of the connecting part, or a portion covering a downstream side rather than the downstream region in the flow passage of exhaust emission.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a mixing device for mixing exhaust gas and a reducing agent in order to purify exhaust gas from an internal combustion engine of a vehicle with a purification device.

  There is known a technique of injecting a reducing agent into the inside of an exhaust pipe in order to purify the exhaust gas with a urea SCR system. For example, in the exhaust system of Patent Document 1, the reflux plate is disposed inside the exhaust pipe so as to cross the flow-down direction of the exhaust, and the reducing agent is injected along the reflux plate. As a result, the vortices generated on the downstream side of the reflux plate reduce the droplets of the reducing agent and promote the evaporation of the reducing agent.

Patent No. 5791569 gazette

However, in the technique of Patent Document 1, although the evaporation of the reducing agent is promoted, the reducing agent can not be well diffused in the exhaust gas.
Good diffusion of the reductant into the exhaust is desirable.

  One aspect of the present disclosure is a mixing device that mixes exhaust gas from an internal combustion engine flowing down from an upstream pipe with a reducing agent for purifying the exhaust gas, and then flows it down to a downstream pipe provided with a purification device. The mixing device comprises a connection and an injection. The connection portion is a portion connecting the upstream pipe and the downstream pipe, and is a portion having the upstream wall surface, the downstream wall surface, and the exhaust flow path. The upstream wall is connected to the upstream pipe. Also, the downstream wall surface is connected to the downstream pipe and faces the upstream wall surface. Also, the exhaust flow path is located between the upstream wall surface and the downstream wall surface. Also, the injection part has a hole provided in the connection part for injecting the reducing agent. In addition, the connection portion has an upstream region and a downstream region as an exhaust flow path. The upstream region is a region facing the upstream opening that forms the downstream end of the upstream pipe. Also, the downstream region is a region facing the downstream opening that forms the upstream end of the downstream pipe.

  Here, a line passing through the center of the upstream opening and extending in the direction toward the upstream opening is taken as an upstream center line. In addition, a line passing through the center of the downstream opening and extending in the direction toward the downstream opening is taken as the downstream center line. In the upstream pipe and the downstream pipe, the upstream center line and the downstream center line extend in the same or substantially the same direction, and the exhaust gas passing through the upstream opening and the downstream opening flows down in the same or substantially the same direction It is configured as follows. In addition, a plane that intersects both the upstream center line and the downstream center line and extends toward the side of the upstream center line is referred to as an intersecting plane. The connection is configured to extend along a curved path on the cross surface. And a hole is located in a portion which covers a downstream field in a connection part, or a field which covers a field downstream rather than a downstream field in a channel of exhaust air.

  According to such a configuration, the exhaust flowed into the connecting portion from the upstream pipe, when flowing out from the upstream region, largely changes the flow down direction, and the flow of the exhaust gas is biased. And a connection part is curving. For this reason, the exhaust gas having flowed out from the upstream region flows along the curve of the connection portion, and flows in a swirling direction in a biased state, and flows into the downstream region. After that, when the exhaust flowing into the downstream region goes to the downstream opening, the flowing direction of the exhaust changes significantly again, and the flow of the exhaust is further biased. At this time, the swirling flow of the exhaust is maintained, and the exhaust flows down the downstream pipe while swirling in a direction intersecting with the flow-down direction.

  That is, when mixing the reducing agent injected from the hole portion of the injection portion with the exhaust flowing down the connection portion, it is possible to generate the swirling flow of the exhaust while giving a bias to the flow of the exhaust. Then, the exhaust gas flows downward toward the purification device while turning.

  Furthermore, since the hole is located at the portion covering the downstream region at the connection portion or at the portion covering the region downstream of the downstream region at the connection portion, the reducing agent is directed toward the swirling flow of the exhaust flowing down the connection portion Is injected. For this reason, the flow is biased and the reducing agent is injected into the swirling exhaust gas.

Therefore, the reducing agent can be well diffused in the exhaust gas.
In one aspect of the present disclosure, the connection may be U-shaped or V-shaped curved from the upstream region to the downstream region.

According to such a configuration, the flow of exhaust gas is biased to one side, and swirling of the exhaust gas can be promoted. Therefore, the reducing agent can be more favorably diffused into the exhaust gas.
In one aspect of the present disclosure, the connection may have a side wall. The side wall is connected to the upstream wall surface and the downstream wall surface, and has an inner peripheral side surface located on the inner peripheral side in the curve and an outer peripheral side surface located on the outer peripheral side in the curve. Here, of the inner peripheral side surface, a portion located on the outermost peripheral side is taken as a peak portion. Further, the direction of the straight line connecting the center of the upstream opening and the center of the downstream opening is taken as the alignment direction. Further, a plane which extends in the alignment direction and passes through the upstream center line is taken as a reference plane. The connection portion may be configured such that the peak portion is located on the reference surface or on the outer peripheral side of the reference surface.

  According to such a configuration, the connection can have a sufficient curvature, and the exhaust can be more rapidly swirled at the connection. Thereby, the reducing agent can be further diffused into the exhaust gas.

  In one aspect of the present disclosure, the connection portion may further include a projecting area adjacent to the downstream side of the downstream area as a flow path of the exhaust. And a hole may be provided in a portion which covers a projection field in a connection part.

  According to such a configuration, the reducing agent injected from the injecting portion collides with the inner wall of the connection portion covering the projecting area, thereby promoting the miniaturization of the reducing agent. Further, the exhaust gas in the swirling flow flows into the projecting region, and the finely divided reducing agent is caught in the exhaust gas in the swirling flow. Thereby, the reducing agent can be further diffused into the exhaust gas.

In one aspect of the present disclosure, the connection may extend from the upstream region in a direction orthogonal or substantially orthogonal to the upstream centerline.
According to such a configuration, when the exhaust gas flows out from the upstream region, the flow direction of the exhaust gas can be rapidly changed, which results in better deviation of the flow of the exhaust gas. Therefore, the reducing agent can be further diffused into the exhaust gas.

In one aspect of the present disclosure, the connection may extend from the downstream region in a direction orthogonal or substantially orthogonal to the downstream centerline.
According to such a configuration, when the exhaust flows into the downstream outlet in the downstream region, it is possible to rapidly change the flow-down direction of the exhaust, which results in better deviation of the flow of the exhaust. Therefore, the reducing agent can be further diffused into the exhaust gas.

In one aspect of the present disclosure, the upstream centerline and the downstream centerline may extend in the same or substantially the same direction.
According to such a configuration, the exhaust gas passing through the upstream opening and the downstream opening can be caused to flow down in the same or substantially the same direction. Therefore, the exhaust flowing down from the upstream pipe and the exhaust flowing down to the downstream pipe can flow down in the same direction. Therefore, the pressure loss can be suppressed as compared with the case where the exhaust flowing down from the upstream pipe and the exhaust flowing down to the downstream pipe flow in different directions.

FIG. 1 is a perspective view of the mixing device, the upstream pipe, and the downstream pipe of the first embodiment. FIG. 2 is a side view of the mixing device, the upstream pipe, and the downstream pipe of the first embodiment. FIG. 3 is a front view of the mixing device of the first embodiment as viewed from the upstream side. FIG. 4 is a perspective view of the mixing device, the upstream pipe, and the downstream pipe of the second embodiment. FIG. 5 is a front view of the mixing device of the second embodiment as viewed from the upstream side. FIG. 6 is a perspective view of the mixing device, the upstream pipe, and the downstream pipe of the third embodiment. FIG. 7 is a side view of the mixing device, the upstream pipe, and the downstream pipe of the third embodiment. FIG. 8 is a perspective view of the mixing device, the upstream pipe, and the downstream pipe of the fourth embodiment. FIG. 9 is a front view of the mixing device of the fourth embodiment as viewed from the upstream side. FIG. 10 is a side view of the mixing device, the upstream pipe, and the downstream pipe of another embodiment.

  Hereinafter, embodiments of the present disclosure will be described using the drawings. The embodiments of the present disclosure are not limited to the following embodiments at all, and may take various forms within the technical scope of the present disclosure.

First Embodiment
[Description of configuration]
The mixing device 1 of the first embodiment of FIGS. 1, 2 and 3 reduces NOx in the exhaust gas of an internal combustion engine (for example, a diesel engine as an example) of a vehicle by a purification device 40 equipped with an SCR catalyst (Selective Catalytic Reduction) 41. Form part of the urea SCR system. The mixing apparatus 1 mixes the exhaust flowing down from the upstream pipe 3 with a reducing agent (for example, urea water) for purifying the exhaust by the SCR catalyst 41. Then, the mixing device 1 causes the exhaust mixed with the reducing agent to flow downward toward the downstream pipe 4 provided with the purification device 40. The upstream pipe 3, the mixing device 1, and the downstream pipe 4 constitute a part of the exhaust flow path of the vehicle. Hereinafter, the upstream side of the exhaust flow direction is referred to simply as the upstream side, and the downstream side of the flow direction is referred to simply as the downstream side.

  In the first embodiment, the end section 31 including the downstream end of the upstream pipe 3 extends linearly and is cylindrical. And as shown in FIG. 3, the upstream opening 30 which is an opening of the downstream end of the upstream pipe 3 is circular.

  Further, the starting end section 42 which is a section including the upstream end portion of the downstream pipe 4 extends linearly and is cylindrical. And the downstream side opening 43 which is an opening of the upstream edge part of the start end area 42 is circular. Further, the downstream end of the start end section 42 is connected to the purification device 40. The purification device 40 has a tapered portion 40 a and a main portion 40 b. The main body 40 b is provided with the SCR catalyst 41 and has a diameter larger than that of the start end section 42. The tapered portion 40 a is tapered and connects the main portion 40 b and the start end section 42.

  The end section 31 of the upstream pipe 3 and / or the start section 42 of the downstream pipe 4 may be bent, for example, or may be a tubular member whose cross section is not circular. Also, the upstream opening 30 and / or the downstream opening 43 is not limited to a circular shape, and may be, for example, an elliptical shape or a polygonal shape.

  Here, a line passing through the center of the upstream opening 30 and extending in the direction in which the upstream opening 30 is directed is taken as an upstream center line 30 a. Further, a line passing through the center of the downstream opening 43 and extending in the direction in which the downstream opening 43 is directed is taken as a downstream center line 43a. Further, one of two spaces separated by a plane including the upstream opening 30 is set as an upstream space, and the other is set as a downstream space. The upstream space is located upstream of the upstream opening 30, and the downstream space is located downstream of the upstream opening 30.

  In the present embodiment, the upstream pipe 3 and the downstream pipe 4 are disposed such that the upstream opening 30 and the downstream opening 43 do not face each other, and the downstream opening 43 is located in the downstream space. Moreover, the downstream pipe | tube 4 is arrange | positioned in the state located in downstream space. Furthermore, the upstream pipe 3 and the downstream pipe 4 are arranged such that the direction of the upstream center line 30a and the direction of the downstream center line 43a are the same or substantially the same. Further, the exhaust gases passing through the upstream opening 30 and the downstream opening 43 flow downward in the same or substantially the same direction.

The mixing apparatus 1 includes a connection unit 10 and an injection unit 2.
The connection portion 10 is a joint-like portion that connects the upstream opening 30 of the upstream pipe 3 and the downstream opening 43 of the downstream pipe 4. As shown in FIGS. 1, 2, and 3, the connection portion 10 includes an upstream wall surface 10 a, a downstream wall surface 10 b, and a side wall 10 c. The upstream wall surface 10 a is connected to the upstream pipe 3, and the downstream wall surface 10 b is connected to the downstream pipe 4. Further, the side wall 10c is connected to the upstream wall surface 10a and the downstream wall surface 10b. In other words, the connection portion 10 constitutes an exhaust flow path surrounded by the upstream wall surface 10a, the downstream wall surface 10b, and the side wall 10c. Further, the connection portion 10 has an upstream region 12, a downstream region 13, and a projecting region 15 as a part of the exhaust flow path.

  The upstream region 12 is a region facing the upstream opening 30. Further, the downstream area 13 is an area facing the downstream opening 43. The upstream area 12 and the downstream area 13 are cylindrical areas. Further, the exhaust flow path of the connection portion 10 has a portion connecting the upstream region 12 and the downstream region 13. The width extending in the direction along the upstream opening 30 in the exhaust gas flow path of the connection portion 10 is equal to or larger than the diameter of the upstream opening 30.

  A plane which intersects both the upstream side center line 30a and the downstream side center line 43a and which spreads to the side of the upstream side center line 30a is referred to as an intersecting plane 11. In the present embodiment, as an example, the cross surface 11 is orthogonal or substantially orthogonal to the upstream center line 30a. The connection 10 extends along a curved path on the cross surface 11. As an example, the connection portion 10 is curved in a U-shape from the upstream region 12 to the downstream region 13. More specifically, the exhaust flow path of the connection portion 10 extends along the path extending on the cross surface 11 from the beginning to the end in a U-shape. The connecting portion 10 may be curved in a V shape from the upstream region 12 to the downstream region 13. Also, the connection portion 10 extends from the side surface of the upstream region 12 in the first side direction 16. Also, the connection portion 10 extends from the side surface of the downstream region 13 in the second side surface direction 17.

  Note that the side surface of the upstream region 12 is a side surface portion of a cylinder that extends along the upstream center line 30 a in the upstream region 12 that is a cylindrical region. Moreover, the side surface of the downstream area | region 13 is a side part of the cylinder extended along the downstream centerline 43a among the downstream area | regions 13 which are column-shaped area | regions.

  Further, the first side surface direction 16 is a direction from the upstream side centerline 30a toward the side of the upstream side centerline 30a. In the first embodiment, as an example, the first side direction 16 is a direction orthogonal to or substantially orthogonal to the upstream center line 30a. In other words, the first side direction 16 is the same as or substantially the same as the tangent of the circular upstream opening 30. However, the first side direction 16 may be inclined upstream or downstream.

  The second side surface direction 17 is a direction from the downstream side center line 43a toward the side of the downstream side center line 43a. In the first embodiment, as an example, the second side surface direction 17 is a direction orthogonal to or substantially orthogonal to the downstream center line 43a. In other words, the second side direction 17 is the same as or substantially the same as the tangent of the circular downstream opening 43. However, the second side direction 17 may be inclined upstream or downstream.

  In addition, the protruding area 15 is adjacent to the downstream side of the downstream area 13. More specifically, the projecting region 15 is a region surrounded by the upstream wall surface 10a, the downstream wall surface 10b, and the side wall 10c, and is a region projecting from the downstream region 13 in the direction opposite to the second side direction 17.

  The upstream wall surface 10a and the downstream wall surface 10b are flat portions and extend in a U-shape. The upstream wall surface 10a covers the exhaust flow path of the connection portion 10 from the side where the upstream pipe 3 is located, and the downstream wall surface 10b covers the exhaust flow path of the connection portion 10 from the side where the downstream pipe 4 is located. That is, the upstream wall surface 10a and the downstream wall surface 10b are disposed in a state of facing each other. Moreover, the upstream wall surface 10a and the downstream wall surface 10b are arrange | positioned in parallel or substantially parallel. Therefore, the upstream wall surface 10a and the downstream wall surface 10b extend in the direction orthogonal or substantially orthogonal to the upstream center line 30a and the downstream center line 43a.

  Then, an inlet connected to the upstream opening 30 is provided at one end of the upstream wall surface 10a. Moreover, the hole 20 which comprises the injection | pouring part 2 mentioned later is provided in the other end of the upstream wall surface 10a. Further, the downstream wall surface 10 b is provided with an outlet connected to the downstream opening 43. Further, the downstream wall surface 10b extends further downstream from the outlet.

  The side wall 10c is a plate-like portion that connects the edge of the upstream wall surface 10a and the edge of the downstream wall 10b. The side wall 10c is connected to the upstream wall surface 10a and the downstream wall surface 10b in a state of having a corner. That is, the connection portion 10 extends so as to bend with respect to the upstream pipe 3 and the downstream pipe 4 when viewed from the side of the upstream pipe 3 and the downstream pipe 4 (hereinafter referred to as a side view). In other words, the flow path of the exhaust in the connection portion 10 is bent in the upstream region 12 and the downstream region 13.

Further, a portion of the upstream wall surface 10a, the downstream wall surface 10b, and the side wall 10c in contact with the flow path of the exhaust is taken as an inner wall.
On the other hand, the injection part 2 is a part to which the injector (not shown) for injecting a reducing agent to the flow path of exhaust_gas | exhaustion is attached. The injection portion 2 is provided in a portion covering the projecting area 15 in the connection portion 10. In more detail, the injection part 2 is provided in the part which covers the protrusion area 15 of the upstream wall surface 10a. In addition, the injection | pouring part 2 may be provided in the part which covers the protrusion area 15 of downstream wall surface 10b or the side wall 10c.

  The injection unit 2 has a hole 20 provided in the connection unit 10 so as to connect the exhaust flow path of the connection unit 10 to the outside. The holes 20 are used to inject the reducing agent from the outside into the exhaust flow path of the connection portion 10. The injection part 2 is a cylindrical part which is arrange | positioned along the edge of the hole 20, and protrudes from the upstream wall surface 10a. Then, the injector injects the reducing agent toward the exhaust flow path of the connection portion 10 through the hole 20. Thereby, the reducing agent is injected into the exhaust flow path of the connection portion 10.

  The hole 20 of the injection part 2 is provided in the part which covers the protrusion area 15 of the upstream wall surface 10a. In addition, when the line passing through the center of the hole 20 and extending in the direction of the hole 20 is taken as the center line of the hole, the center line is directed in the same or substantially the same direction as the direction of the downstream center line 43a. ing. However, the hole 20 may be provided, for example, in a portion covering the downstream wall surface 10 b or the protruding region 15 of the side wall 10 c.

  Here, the direction of the straight line connecting the center of the upstream opening 30 and the center of the downstream opening 43 is taken as the alignment direction. Further, a plane which extends in the alignment direction and which includes the upstream center line 30a is taken as a reference plane 30b.

  Moreover, let the part located in the inner peripheral side of the curve of the connection part 10 among the side walls 10c be the inner peripheral side 10c-2, and let the part located in the outer peripheral side be outer peripheral side 10c-1. Moreover, let the part located in the outermost periphery among the inner peripheral side 10c-2 be the peak part 14. FIG. More specifically, the path extending in the flow-down direction of the exhaust along the inner circumferential side surface 10c-2 of the connection portion 10 is taken as the inner circumferential path. In the inner circumferential side path, the portion located on the outermost circumferential side is included in the peak portion 14. In other words, in the inner circumferential side path, the peak portion 14 includes the position farthest from the straight line connecting both ends of the inner circumferential side path.

  In the first embodiment, the connection portion 10 is configured such that the peak portion 14 is located on the reference surface 30 b. In addition, the connection part 10 may be comprised so that the peak part 14 may be located in the outer peripheral side rather than the reference plane 30b. Also, for example, the connection portion 10 may be configured such that all the middle portions of the inner peripheral side surface 10c-2 are located on the reference surface 30b or on the outer peripheral side of the reference surface 30b. In addition, an intermediate part is a part which covers the part which connects the upstream area | region 12 of the flow path of the exhaust_gas | exhaustion of the connection part 10, and the downstream area | region 13 in inner peripheral side 10c-2.

[effect]
(1) According to the mixing device 1 of the first embodiment, the exhaust flowed from the upstream pipe 3 into the connection portion 10 is significantly changed in the flow down direction when flowing out from the upstream region 12, and the flow of the exhaust is uneven. It occurs. And the connection part 10 is curving. Therefore, the exhaust gas having flowed into the upstream region 12 flows along the curve of the connection portion 10 to flow in a swirling direction in a biased state, and flows into the downstream region 13. Thereafter, when the exhaust gas flowing into the downstream region 13 travels to the downstream side opening 43, the flow-down direction of the exhaust gas greatly changes again, and the flow of the exhaust gas is further biased. At this time, the swirling flow of the exhaust is maintained, and the exhaust flows down the downstream pipe 4 while swirling in a direction intersecting with the flow-down direction.

  That is, when mixing the reducing agent injected from the hole 20 of the injection part 2 with the exhaust flowing down the connection part 10, it is possible to generate a swirling flow of exhaust while giving deviation to the flow of the exhaust. . Then, the exhaust gas flows downward toward the purification device 40 while turning. Thereby, the reducing agent can be well diffused in the exhaust gas.

  Further, the exhaust gases passing through the upstream opening 30 and the downstream opening 43 flow downward in the same or substantially the same direction. Therefore, the exhaust flowing down from the upstream pipe 3 and the exhaust flowing down to the downstream pipe 4 flow in the same direction. Therefore, the reducing agent can be well diffused in the exhaust while the pressure loss is reduced, as compared with the exhaust flowing down from the upstream pipe 3 and the exhaust flowing down to the downstream pipe 4 flowing in different directions.

  In addition, the hole 20 is located at a portion covering the projecting region 15 in the upstream wall surface 10 a, and the reducing agent is injected toward the swirling flow of the exhaust flowing down the connection portion 10. For this reason, the flow is biased and the reducing agent is injected into the swirling exhaust gas. Therefore, the reducing agent can be well diffused in the exhaust gas.

  (2) Further, the connection portion 10 is curved in a U shape from the upstream region 12 to the downstream region 13. For this reason, the flow of exhaust gas is biased to one side, and the turning can be increased. Therefore, the reducing agent can be well diffused in the exhaust gas.

  (3) Moreover, the connection part 10 is comprised so that the peak part 14 may be located in the outer peripheral side rather than the reference plane 30b. Therefore, the connection portion 10 can have a sufficient curvature, and the exhaust can be more rapidly swirled. Thereby, the reducing agent can be further diffused into the exhaust gas.

  (4) Moreover, the hole 20 is provided in the part which covers the protrusion area 15 in the upstream wall surface 10a. For this reason, the reducing agent injected from the injection part 2 collides with the inner wall of the connection part 10, thereby promoting the miniaturization of the reducing agent. Further, the exhaust gas in the swirling flow flows into the projecting region 15 from the side in the injection direction of the reducing agent, and the finely divided reducing agent is caught in the exhaust gas in the swirling flow. Thereby, the reducing agent can be further diffused into the exhaust gas.

  (5) Further, the connecting portion 10 extends from the upstream region 12 in a direction orthogonal or substantially orthogonal to the upstream center line 30a, and extends from the downstream region 13 in a direction orthogonal or substantially orthogonal to the downstream center line 43a . Thus, the flow-down direction of the exhaust can be rapidly changed when the exhaust flows out from the upstream region and when the exhaust flows into the downstream outlet in the downstream region. For this reason, the flow of the exhaust gas is better biased, and as a result, the reducing agent can be further diffused into the exhaust gas.

Second Embodiment
The mixing device 1 of the second embodiment in FIGS. 4 and 5 has the same configuration as that of the first embodiment. However, the mixing device 1 of the second embodiment is different from the first embodiment in the configuration of the connection portion 10 and the position of the injection portion 2.

  That is, in the second embodiment, the connection portion 10 has the upstream region 12 and the downstream region 13 and does not have the projecting region 15. For this reason, although the upstream wall surface 10a and the downstream wall surface 10b of the connection part 10 of 2nd Embodiment are extended in a U-shape similarly to 1st Embodiment, the length is shorter than 1st Embodiment. Further, an outlet connected to the downstream opening 43 is provided at the other end of the downstream wall surface 10b.

  Further, in the second embodiment, the injection portion 2 is provided in a portion covering the downstream region 13 in the connection portion 10. More specifically, the hole portion 20 of the injection portion 2 is provided in a portion covering the downstream region 13 in the upstream wall surface 10 a of the connection portion 10. When the hole 20 faces the downstream opening 43, passes through the center of the hole 20, and the line extending in the direction of the hole 20 is the center line of the hole, the center line is the downstream center line 43a. The direction is the same as or substantially the same as the direction of. However, the hole 20 may be provided, for example, in a portion covering the downstream region 13 in the side wall 10 c of the connection portion 10.

[effect]
Also in the mixing apparatus 1 of the second embodiment, the same effect as that of the first embodiment can be obtained.
Further, although the connection portion 10 extends in a U-shape as in the first embodiment, the length is shorter than that in the first embodiment, so that the layout can be optimized according to the arrangement of the injector.

Third Embodiment
The mixing device 1 of the third embodiment in FIGS. 6 and 7 has the same configuration as that of the second embodiment. However, in the mixing device 1 of the third embodiment, the orientation of the connection portion 10 with respect to the upstream center line 30 a and the downstream center line 43 a is different from that of the second embodiment.

  That is, also in the third embodiment, the connection portion 10 extends from the upstream region 12 in the first lateral direction 16 and extends from the downstream region 13 in the second lateral direction 17. However, in the second embodiment, the first side direction 16 is a direction orthogonal to or substantially orthogonal to the upstream center line 30a, but in the third embodiment, the first side direction 16 is the upstream center line The direction perpendicular to the line orthogonal to 30 a is inclined X ° downstream. In other words, the connection portion 10 extends along the curved path on the intersecting surface 11 which is inclined to the downstream side by X ° with respect to the upstream center line 30 a. Further, in the second embodiment, the second side surface direction 17 is a direction orthogonal to or substantially orthogonal to the downstream side center line 43a, but in the third embodiment, the second side direction 17 is the downstream side center line The direction perpendicular to the line 43a is inclined to the upstream side by Y °.

  Note that X ° and Y ° may be predetermined angles, and X ° and Y ° may be the same or substantially the same angle. Also, only one of the first side direction 16 and the second side direction 17 may be different from the second embodiment.

  For this reason, in the third embodiment, the upstream wall surface 10a and the downstream wall surface 10b of the connection portion 10 are inclined to the downstream by X ° with respect to a line perpendicular to the upstream center line 30a. In addition, the upstream wall surface 10a and the downstream wall surface 10b are inclined to the upstream side by Y ° with respect to a line orthogonal to the downstream center line 43a.

  Moreover, the connection part 10 of 3rd Embodiment has the entrance connection part 10e and the exit connection part 10f, in order to form inclination. The inlet connection portion 10e is a cylindrical portion that protrudes from one end of the upstream wall surface 10a. An opening at one end of the inlet connection 10 e is connected to the upstream opening 30. The outlet connection portion 10f is a cylindrical portion that protrudes from the other end of the downstream wall surface 10b. An opening at one end of the outlet connection 10 f is connected to the downstream opening 43.

[effect]
Also in the mixing apparatus 1 of the third embodiment, the same effects as in the first and second embodiments can be obtained.
Moreover, since the connection part 10 inclines, the pressure loss at the time of exhaust_gas | exhaustion flowing down the connection part 10 can be suppressed.

Fourth Embodiment
The mixing device 1 of the fourth embodiment in FIGS. 8 and 9 has the same configuration as that of the second embodiment. However, in the mixing apparatus 1 of the fourth embodiment, the shape of the connection portion 10 is different from that of the second embodiment.

  In the fourth embodiment, the connection portion 10 is curved in a V shape from the upstream region 12 to the downstream region 13. More specifically, the outer peripheral side surface 10c-1 of the connection portion 10 includes a V-shaped curved portion, and the above-described middle portion of the inner peripheral side surface 10c-2 extends linearly. In addition, the exhaust gas flow path of the connection portion 10 has a portion in which the width along the upstream side opening 30 is narrower than the diameter of the upstream side opening 30.

  Further, the middle portion of the inner peripheral side surface 10c-2 of the connection portion 10 extends along the reference surface 30b. Moreover, the peak part 14 of the connection part 10 is located on the reference plane 30b. The peak portion 14 may be located on the outer peripheral side of the reference surface 30 b.

  For this reason, the upstream wall surface 10a and the downstream wall surface 10b of the connection part 10 of 4th Embodiment are curving in V shape. Moreover, the part in contact with the middle part of inner peripheral side side 10c-2 in the edge of upstream wall surface 10a and downstream wall surface 10b is linear form. Moreover, the part which touches the outer peripheral side side surface 10c-1 of the connection part 10 in the edge part of the upstream wall surface 10a and the downstream wall surface 10b is curving in V shape.

[effect]
Also in the mixing apparatus 1 of the fourth embodiment, the same effects as in the first to third embodiments can be obtained.
Further, in the exhaust gas flow path of the connection portion 10, a portion in which the width along the upstream side opening 30 is narrower than the diameter of the upstream side opening 30 is provided. For this reason, the flow velocity of the exhaust flowing down the connection portion 10 can be increased, and the reducing agent can be further favorably diffused in the exhaust.

[Other embodiments]
(1) In the first to fourth embodiments, the connection portion 10 is bent in the upstream region 12 and the downstream region 13 in a side view. However, the connection portion 10 may be curved in both or one of the upstream region 12 and the downstream region 13 when viewed from the side. Specifically, for example, as shown in FIG. 10, the connecting portion 10 may be curved in both the upstream region 12 and the downstream region 13 when viewed from the side. Even in such a case, the same effect can be obtained.

  (2) In the first to fourth embodiments, in the mixing device 1, the upstream pipe 3, and the downstream pipe 4, the direction of the upstream center line 30a and the direction of the downstream center line 43a are the same or substantially the same. It is configured to be However, the mixing device 1, the upstream pipe 3, and the downstream pipe 4 may be configured such that the direction of the upstream center line 30 a and the direction of the downstream center line 43 a are different. In addition, the end section 31 of the upstream pipe 3 may extend in the direction of the upstream center line 30a, or may extend in a direction different from this. Moreover, the start end section 42 of the downstream pipe 4 may extend in the direction of the downstream center line 43a, or may extend in a direction different from this.

  (3) The plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components . Also, a plurality of functions possessed by a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. In addition, part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above-described embodiment may be added to or replaced with the configuration of the other above-described embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Mixing apparatus, 2 ... Injection | pouring part, 3 ... Upstream pipe, 4 ... Downstream pipe, 10 ... Connection part, 10a ... Upstream wall surface, 10b ... Downstream wall surface, 10c ... Side wall, 10c-1 ... Outer peripheral side, 10c-2 ... inner side surface, 11 ... intersection surface, 12 ... upstream region, 13 ... downstream region, 14 ... peak portion, 15 ... projecting region, 20 ... hole portion, 30 ... upstream opening, 30a ... upstream center line, 30b ... reference plane, 40 ... purification device, 43 ... downstream opening, 43a ... downstream center line.

Claims (7)

A mixing device for mixing exhaust gas from an internal combustion engine flowing down from an upstream pipe with a reducing agent for purifying the exhaust gas and then flowing it down to a downstream pipe provided with a purification device,
The mixing device is
An upstream wall surface connecting the upstream pipe and the downstream pipe, and an upstream wall surface connected to the upstream pipe, a downstream wall surface connected to the downstream pipe and facing the upstream wall surface, and the upstream wall surface and the downstream wall surface A connection portion which is a portion having the flow path of the exhaust gas located between the
An injection part having a hole provided in the connection part for injecting the reducing agent;
Equipped with
The connection portion is used as a flow path of the exhaust gas.
An upstream region, which is a region facing the upstream opening forming the downstream end of the upstream pipe;
A downstream region, which is a region facing the downstream opening forming the upstream end of the downstream pipe;
Have
A line passing through the center of the upstream opening and extending in the direction to which the upstream opening is directed is an upstream center line,
A line passing through the center of the downstream opening and extending in the direction toward the downstream opening is a downstream center line,
A plane which intersects both the upstream center line and the downstream center line and which extends toward the side of the upstream center line is referred to as a cross plane.
The connection is configured to extend along a curved path on the cross surface,
The mixing unit is located in a portion of the connection portion that covers the downstream region or a portion that covers a region downstream of the downstream region in the flow path of the exhaust gas. In the mixing device according to claim 1,
The mixing device, wherein the connection portion is curved in a U-shape or a V-shape from the upstream area to the downstream area. In the mixing device according to claim 2,
The connecting portion is connected to the upstream wall surface and the downstream wall surface, and has a side wall having an inner peripheral side surface located on the inner peripheral side in the curve and an outer peripheral side surface located on the outer peripheral side in the curve. And
A portion of the inner peripheral side surface located closest to the outer peripheral side is a peak portion,
The direction of a straight line connecting the center of the upstream opening and the center of the downstream opening is a row direction,
A plane extending in the alignment direction and passing through the upstream center line is a reference plane,
The connecting portion is configured such that the peak portion is located on the reference surface or the outer peripheral side of the reference surface. In the mixing device according to any one of claims 1 to 3,
The connection portion further includes a projecting area adjacent to the downstream side of the downstream area as a flow path of the exhaust gas,
The hole is provided in a portion covering the projecting area in the connection portion. The mixing apparatus according to any one of claims 1 to 4
The mixing device, wherein the connection portion extends from the upstream region in a direction orthogonal or substantially orthogonal to the upstream center line. The mixing apparatus according to any one of claims 1 to 5,
The mixing device, wherein the connection portion extends from the downstream region in a direction orthogonal or substantially orthogonal to the downstream center line. The mixing apparatus according to any one of claims 1 to 6,
A mixing device, wherein the upstream centerline and the downstream centerline extend in the same or substantially the same direction.

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