JP2018184845A - Exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of uniformly diffusing an additive injected from an addition valve in an exhaust passage (exhaust pipe) regardless of a level of a flow rate of exhaust gas without increasing the size of the exhaust emission control device.SOLUTION: An exhaust emission control device includes: an exhaust emission control catalyst; an addition valve 21 for injecting an additive into an exhaust passage 45 upstream of the exhaust emission control catalyst; and a plate-like diffusion member 51 provided in the exhaust passage upstream of the addition valve to partially block a flow of exhaust gas and diffusing the additive that has been injected from the addition valve and collided in the exhaust passage. The additive is injected toward the upstream side by the addition valve so that a spray collides with the diffusion member. The diffusion member includes: collision portions S1, S2, S3 with which the spray of the additive collides; and a cover portion provided to overlap with the spray of the additive viewed from the upstream side in the flowing direction of exhaust gas.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an exhaust purification device that purifies exhaust gas by supplying an additive to an exhaust purification catalyst provided in an exhaust passage of an internal combustion engine.

  As an exhaust emission control device for a vehicle equipped with a conventional diesel engine, for example, as shown in Patent Document 1, an additive (reducing agent) is injected from an addition valve into an exhaust pipe upstream of the exhaust purification catalyst, and the exhaust purification catalyst. An exhaust purification device that purifies NOx (nitrogen oxide) is known. In order to efficiently purify NOx with this type of exhaust purification device, it is necessary to uniformly diffuse the additive in the exhaust pipe so that the additive injected from the addition valve does not concentrate on a part of the exhaust purification catalyst. There is. With respect to this problem, Patent Document 1 is provided with a weir plate that partially blocks the flow of exhaust gas on the upstream side of the addition valve so that the additive can be diffused well even when the flow rate of the exhaust gas increases. .

JP 2008-208761 A

  However, in the configuration described in Patent Document 1, a dam plate that partially blocks the flow of the exhaust gas so as to improve the diffusibility of the reducing agent (additive) injected from the addition valve when the flow rate of the exhaust gas is large is provided. Therefore, when the flow rate of the exhaust gas is small, there is a possibility that the dam plate may cause the diffusibility of the reducing agent to deteriorate. That is, since the injection pressure of the reducing agent in the addition valve is constant, if the barrier plate blocks the flow of exhaust gas when the flow rate of exhaust gas is small, the reducing agent injected from the addition valve rides on the flow of exhaust gas. Before it diffuses, it reaches the inner wall of the exhaust pipe facing the addition valve. As a result, the concentration distribution of the reducing agent is distorted. Moreover, since the structure described in Patent Document 1 diffuses the reducing agent into the exhaust pipe by the flow of the exhaust gas, in order to diffuse the reducing agent uniformly, the diffusion distance from the addition valve to the exhaust purification catalyst is increased. There is also a problem that the exhaust purification device needs to be long enough and the exhaust purification device becomes large.

  The present invention has been devised in view of such points, and does not increase the size of the exhaust gas purification device, and regardless of the flow rate of the exhaust gas, the additive injected from the addition valve can be discharged into the exhaust passage. It is an object of the present invention to provide an exhaust purification device capable of uniformly diffusing in an (exhaust pipe).

  In order to solve the above-mentioned problems, the first invention is an exhaust purification catalyst provided in an exhaust passage of an internal combustion engine, and an additive in the exhaust passage upstream of the exhaust purification catalyst in the flow direction of the exhaust gas. An injection valve to be injected, and provided in the exhaust passage upstream of the addition valve in the flow direction of the exhaust gas to partially block the flow of exhaust gas in the exhaust passage and to be injected from the addition valve A plate-like diffusion member that collides with the spray of the additive and diffuses the additive into the exhaust passage, wherein the addition valve is added to the back side of the diffusion member So that the spray of the agent collides, the additive is injected toward the upstream side in the flow direction of the exhaust gas, and the diffusion member collides with the spray of the additive injected from the addition valve, Diffusion member upstream of exhaust gas flow direction And a cover part which overlaps the spray of injected additive from the addition valve as seen from an exhaust gas purification device.

  A second invention is the exhaust emission control device according to the first invention, wherein the addition valve has a plurality of injection holes, and an additive injected from each of the plurality of injection holes is the exhaust passage. The additive is injected so as to form sprays of a plurality of additives that are spaced apart from each other, and the diffusion member includes the impingement part and the cover respectively corresponding to the sprays of the plurality of additives injected from the addition valve. And an exhaust purification device.

  A third invention is the exhaust emission control device according to the first invention or the second invention, wherein at least one of the cover portions is a long cover portion having a long shape, The additive spray injected from the addition valve forms a conical spray, and the addition valve has a width of the cone spray of the additive injected into the exhaust passage. The exhaust emission control device injects the additive at a narrow angle so as to be narrower than the width of the exhaust gas.

  According to the first invention, the additive is injected toward the diffusion member arranged upstream in the exhaust passage. The diffusion member has a cover portion that is provided so as to overlap with the additive injected from the addition valve when viewed from the upstream side in the flow direction of the exhaust gas. Regardless of the size, it collides directly with the collision part of the diffusing member. The spray of the additive that has collided with the diffusion member is scattered in various directions from the collision part or flows along the cover part of the diffusion member, and is widely diffused in the radial direction in the exhaust passage. Further, since the spray of additive is diffused by colliding with the diffusion member before being diffused by the flow of exhaust gas, the distance from the addition valve to the exhaust purification device can be further shortened, and exhaust purification is achieved. An increase in size of the apparatus can be suppressed.

  According to the second invention, each of the sprays of the plurality of additives sprayed from each of the plurality of nozzle holes is diffused from the respective collision portions arranged at appropriate intervals. It is diffused more uniformly in the radial direction.

  According to the third aspect of the invention, the additive is injected at a narrow angle so that the width of the conical spray injected into the exhaust passage is narrower than the width of the long cover portion. As a result, when viewed from the upstream side in the exhaust gas flow direction, the injected conical spray overlaps the cover part without protruding from the cover part from the nozzle hole to the collision part, and all reaches the collision part. it can.

It is a figure explaining the schematic structure of the internal combustion engine to which the exhaust emission control device of the present invention is applied. It is a perspective view explaining the outline | summary of the exhaust gas purification apparatus of 1st Embodiment. FIG. 3 is a front view of a diffusion member of the exhaust emission control device according to the first embodiment as viewed from the III direction in FIG. 2. In 1st Embodiment, when the flow volume of exhaust gas is large, it is a figure explaining a mode that the vaporized additive diffuses. In 1st Embodiment, when the flow volume of exhaust gas is small, it is a figure explaining a mode that the vaporized additive diffuses. It is a figure which shows the calculation result using a simple simulation model about the diffusion degree of the vaporized additive in an exhaust passage with respect to the magnitude | size of the flow volume of exhaust gas. It is a perspective view explaining the outline | summary of the exhaust gas purification apparatus of 2nd Embodiment. FIG. 8 is a front view of a diffusion member of the exhaust emission control device according to the second embodiment as viewed from the VIII direction in FIG. 7. It is a perspective view explaining the outline | summary of the exhaust gas purification apparatus of 3rd Embodiment. FIG. 10 is a front view of a diffusion member of an exhaust emission control device according to a third embodiment viewed from the X direction in FIG. 9. It is a perspective view explaining the outline | summary of the exhaust gas purification apparatus of 4th Embodiment. It is a front view of the diffusion member of the exhaust emission control device of the fourth embodiment viewed from the XII direction of FIG. It is a figure explaining the outline | summary of the exhaust gas purification apparatus of 5th Embodiment, and is a figure explaining the state which has arrange | positioned the diffusion member so as to be orthogonal to the center axis line of an addition valve. It is a figure explaining the outline | summary of the exhaust gas purification device of 6th Embodiment, arrange | positions two addition valves on the left and right of an exhaust passage, arranges two diffusion members on the left and right in an exhaust passage, It is a figure explaining a mode that a reducing agent is injected to each of two spreading | diffusion members from this addition valve. It is a figure explaining the structure of [Example 1 of the conventional exhaust gas purification device] as a comparative example. It is a figure explaining the structure of [the example 2 of the conventional exhaust gas purification device] as a comparative example.

● [Configuration of Internal Combustion Engine to which Exhaust Purification Device 50 is Applied (FIG. 1)]
EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. First, an example of an internal combustion engine to which the exhaust emission control device 50 of the present invention is applied will be described with reference to FIG. In the exhaust path 12 of the internal combustion engine 10 (in this case, a diesel engine), as an exhaust purification device 50, an oxidation catalyst 41, a filter 42, and a selective reduction catalyst 43 (in this case, urea SCR, which is an exhaust purification catalyst) ) And an oxidation catalyst 44 are sequentially provided. A diffusion member 51 and an addition valve 21 are disposed between the filter 42 and the selective reduction catalyst 43. The oxidation catalyst 41 is a catalyst that renders hydrocarbons (HC) and carbon monoxide (CO) harmless, and the filter 42 is a so-called DPF (Diesel Particulate Filter) that collects particulate matter in the exhaust gas. The selective reduction catalyst 43 is a catalyst that renders nitrogen oxides (NOx) harmless by using an additive (in this case, urea water) injected from the addition valve 21 and diffused by the diffusion member 51. The catalyst 44 is a catalyst that detoxifies excess additives that are not used in the reaction in the selective reduction catalyst 43. In the configuration shown in FIG. 1, the filter 42 may be omitted by using a catalyst in which the selective reduction catalyst and the DPF are integrated instead of the selective reduction catalyst 43.

  The exhaust purification device 50 includes an addition valve 21, a diffusion member 51, and a selective reduction catalyst 43. The addition valve 21 has an additive (in this case urea) corresponding to the selective reduction catalyst 43 in the exhaust passage 45 upstream of the selective reduction catalyst 43 (in this case, urea SCR) provided in the internal combustion engine. Water and a reducing agent). The diffusion member 51 promotes the additive injected from the addition valve 21 to vaporize and diffuse into the exhaust passage 45 before reaching the selective reduction catalyst 43 in the exhaust passage 45. The addition valve 21 of the exhaust purification device 50 injects an additive for purifying NOx in the exhaust gas from the upstream side of the selective reduction catalyst 43 toward the diffusion member 51. The injected additive collides with the diffusion member 51 and scatters in various directions, is vaporized by the high-temperature exhaust gas, diffuses in the radial direction in the exhaust passage 45, and is effectively mixed with the exhaust gas. .

  The additive is supplied to the addition valve 21 from the additive tank 22 through the discharge pipe H2. The additive tank 22 is provided with a pressure detection means 26 (for example, a pressure sensor) and a pump 23 via a pipe H1. For example, the control device 25 controls the pump 23 based on the detection signal from the pressure detection means 26 so that the pressure in the additive tank 22 becomes a predetermined pressure, and the hydraulic pressure of the additive supplied to the addition valve 21. Is maintained at a constant pressure.

  The control device 25 can control each of the addition valve 21 and the pump 23 by outputting a control signal. The control device 25 can adjust the supply amount of the additive by controlling the opening degree and energization time of the addition valve 21.

  The control device 25 receives a detection signal from the intake air flow rate detection means 31, a detection signal from the NOx detection means 32, a detection signal from the accelerator opening detection means 33, and a detection signal from the rotation detection means 34. And the control apparatus 25 can detect the driving | running state of the internal combustion engine 10 based on the signal from these detection means. Although not shown, the control device 25 outputs a drive signal to an injector that injects fuel into the internal combustion engine 10. The intake air flow rate detection means 31 is provided in the intake path 11 of the internal combustion engine 10 and outputs a detection signal corresponding to the flow rate of air taken in by the internal combustion engine 10. The NOx detection means 32 is provided in the exhaust path 12 of the internal combustion engine 10 and outputs a detection signal corresponding to NOx in the exhaust gas of the internal combustion engine 10. The accelerator opening detection means 33 outputs a detection signal corresponding to the accelerator opening (that is, the driver's required load) operated by the driver. The rotation detector 34 outputs a detection signal corresponding to the rotation of the crankshaft of the internal combustion engine 10, for example. The control device 25 obtains the amount of additive to be injected from the addition valve 21 based on the detected intake air flow rate, NOx, the required load, and the rotational speed of the internal combustion engine, and controls the pump 23 and the addition valve 21. Thus, the determined amount of additive is injected from the addition valve 21.

  Hereinafter, the first to sixth embodiments of the exhaust emission control device 50 will be described with reference to FIGS. In addition, when the thick solid line arrow is described in the drawing, the thick solid line arrow indicates the direction in which the exhaust gas flows in the exhaust passage 45. In addition, when the X axis, the Y axis, and the Z axis are described in the drawing, the Z axis direction is a direction upward in the vertical direction, the X axis direction is an axial direction of the exhaust passage 45 and a direction from upstream to downstream, The Y-axis direction indicates the left direction when the downstream side is viewed from the upstream side of the exhaust passage 45. In the diffusing member 51, the upstream surface of the exhaust passage 45 is referred to as “front”, and the downstream surface of the diffusing member 51 is referred to as “back”. Also, the Z axis direction is “up”, the opposite direction to the Z axis direction is “down”, the X axis direction is “rear”, the opposite side to the X axis direction is “front”, the Y axis direction is “left”, the Y axis The direction opposite to the direction will be described as “right”. 2, 3, 7, 8, 9, 10, 11, and 12, illustration of the connection portion between the addition valve 21 and the exhaust passage 45 is omitted for convenience of explanation.

[Structure and operation of the exhaust emission control device 50 of the first embodiment (FIGS. 2 and 3)]
In the exhaust purification apparatus 50 of the first embodiment, the diffusion member 51 in FIG. 1 is a diffusion member 51a. The exhaust purification apparatus 50 includes an addition valve 21, a diffusion member 51a, and a selective reduction catalyst 43 (not shown). 1). In the first embodiment, as shown in FIGS. 2 and 3, the diffusing member 51a has a T-shape, and has three collision portions S1, S2, S3 (disposed at the lower center). It has a collision part S1 and collision parts S2, S3) arranged on the upper left and right. The addition valve 21 collides the conical spray 54 from the injection hole 52a to the collision part S1, the conical spray 54 from the injection hole 52b to the collision part S2, and the conical spray 54 from the injection hole 52c to the collision part S3. Let

  As shown in FIG. 2, the addition valve 21 is provided in the exhaust passage 45 downstream of the diffusion member 51a and upstream of the selective reduction catalyst 43 (see FIG. 1). As shown in FIG. 1, the addition valve 21 is fixed above the exhaust passage 45.

  As shown in FIG. 3, the addition valve 21 has three injection holes 52a, 52b, and 52c, and the additive (in this case, urea water) is injected conically from the injection holes 52a, 52b, and 52c. Thus, the conical sprays 54 that are separated from each other are formed. The respective conical sprays 54 ejected from the respective nozzle holes are ejected so as to directly collide with the respective collision portions S1, S2, and S3 provided on the back surface of the diffusion member 51a. The additive sprayed from the nozzle holes is sprayed as a number of particulate liquids, and the conical spray 54 is formed of the number of particulate liquids. In this way, the addition valve 21 has a plurality of injection holes, and the additive is injected so that the additive injected from each of the plurality of injection holes forms a plurality of conical sprays that are separated from each other in the exhaust passage. Spray.

  As shown in FIG. 2, the diffusing member 51 a is provided upstream of the addition valve 21 in the exhaust passage 45 so as to be orthogonal to the axial direction of the exhaust passage 45. The diffusing member 51a has a long covering portion A1 and covering portions A2 and A3. The long covering portions A1, A2 and A3 correspond to the respective injection holes from the injection holes 52a, 52b and 52c when viewed from the upstream side to the downstream side along the axial direction of the exhaust passage 45. It is provided so as to overlap the entire conical spray 54 up to the colliding portions S1, S2, and S3, and covers the entire conical spray 54. The diffusion member 51 a has a collision portion and a cover portion respectively corresponding to the plurality of conical sprays 54 injected from the addition valve 21, and partially blocks the flow of exhaust gas in the exhaust passage 45. In addition, 1st Embodiment has shown the example whose at least 1 cover part (in this case code | symbol A1) is a elongate cover part. Further, the collision portion is at least a partial region of the downstream surface of the diffusion member 51a in the exhaust gas flow direction.

  2 and 3, a cut surface obtained by cutting the exhaust passage 45 along a virtual plane including the back surface of the plate-like diffusion member 51a is referred to as a virtual cross section VD1. The center of the virtual cross section VD1 is defined as the center CP. Since the addition valve 21 has three nozzle holes, as shown in FIG. 3, the virtual cross section VD1 is divided into three fan-like virtual dividing planes D1, D2, and D3 so as to be substantially uniform. . That is, in the virtual cross section VD1 in FIG. 3, the lower fan shape divided by the alternate long and short dash line is divided by the virtual dividing plane D1, and the upper right fan shape divided by the alternate long and short dash line is divided by the virtual dividing plane D2 and the alternate long and short dash line. The upper left fan shape is defined as a virtual dividing plane D3. And the position of collision part S1, S2, S3 is set corresponding to each of the virtual division surfaces D1, D2, and D3. A straight line on the virtual cross section VD1 passing through the center CP and parallel to the Z-axis direction is defined as a center line C1. The diffusing member 51a has a shape having collision portions S1, S2, and S3.

  Collision portions S1, S2, and S3 indicated by dotted lines are arranged at positions corresponding to the virtual dividing surfaces D1, D2, and D3 in the diffusing member 51a. As shown in FIG. 3, the collision part S1 has a collision part center SC1, the collision part S2 has a collision part center SC2, and the collision part S3 has a collision part center SC3. When the respective conical sprays 54 reach and collide with the respective collision portions S1, S2, and S3, the central axes of the respective conical sprays pass through the collision portion centers SC1, SC2, and SC3, respectively. Further, as shown in FIGS. 2 and 3, in the virtual cross section VD1 (that is, in the exhaust passage 45), when viewed from the upstream side in the flow direction of the exhaust gas, the long covering portion A1, covering portions A2 and A3 are These are provided so as to overlap with each conical spray 54. That is, when viewed from the upstream side in the exhaust gas flow direction, each of the conical sprays 54 is entirely covered without protruding from the long covering portion A1, the covering portions A2 and A3.

  As shown in FIG. 3, the long covering portion A1 has a long shape extending from the vicinity of the injection hole 52a toward the collision portion S1. The long cover portion A1 is viewed from the upstream side in the exhaust gas flow direction, and the conical spray 54 from the vicinity of the nozzle hole 52a (from the position reaching the exhaust passage 45) to the collision portion S1. It overlaps with the whole and covers the whole. The long covering portion A1 has a long region from the upper part of the diffusing member 51a shown in the dotted line in the vicinity of the injection hole 52a to the vicinity of the center CP and the diffusing member from the vicinity of the center CP shown by the solid line. This is an area composed of an elongated portion up to the lower end of 51a, and is a hatched area. In FIG. 3, the direction perpendicular to both the longitudinal direction of the long cover portion A1 and the axial direction of the exhaust passage 45 (that is, the left-right direction in FIG. 3) is the long portion width direction, and the long cover The length of the long portion width direction of the portion A1 is defined as a long portion width W1. Further, the length of the conical spray 54 in the width direction of the long portion when the conical spray 54 sprayed from the nozzle hole 52a reaches the collision portion S1 of the long covering portion A1 is the conical spray width L1. And In this case, the cone spreading angle θ1 of the conical spray 54 injected toward the collision portion S1 is set to a narrow angle that is an angle at which the conical spray width L1 becomes narrower than the long portion width W1. Yes. Further, the collision part center SC1 is on the center line C1, and the collision part S1 is set so that the outer periphery of the collision part S1 does not cover the outer edge of the diffusion member 51a. The collision part S1 is a position where the vaporized additive 53 is evenly diffused in the virtual division surface D1 when the conical spray 54 collides with the collision part S1 (that is, approximately the center in the virtual division surface D1). Is set to As shown in FIGS. 2 and 3, the conical spray 54 injected from the injection hole 52a is injected so as to be contained in the collision part S1 when it collides with the collision part S1. In this way, the addition valve 21 has a width (conical spray width L1) of the conical spray injected into the exhaust passage (conical spray corresponding to the collision portion S1) (width of the long covering portion A1). The additive is injected at a narrow angle so as to be narrower than the scale portion width W1).

  When viewed from the upstream side in the flow direction of the exhaust gas, the long covering portion A1 covers the conical spray 54 from the injection hole 52a to the collision part S1, so that the additive injected from the injection hole 52a Until the conical spray 54 collides with the collision part S1, the influence of the exhaust gas flow is suppressed. That is, the long covering portion A1 suppresses the additive from flowing downstream due to the flow of the exhaust gas in the exhaust passage 45. The additive that collides with and collides with the collision part S1 is vaporized by the high-temperature exhaust gas, and the vaporized additive 53 diffuses into the exhaust passage 45 around the collision part S1 in the virtual dividing plane D1.

  As shown in FIG. 3, the cover part A2 and the cover part A3 are positions and shapes that are line-symmetric with respect to the center line C1, and the structure and operation are the same. Therefore, the description of the cover part A3 is omitted. Only the cover A2 will be described. The cover portion A2 overlaps with the entire conical spray 54 from the vicinity of the nozzle hole 52b (from the position reaching the exhaust passage 45) to the collision portion S2 when viewed from the upstream side in the exhaust gas flow direction. It covers the whole. The conical spray 54 injected from the injection hole 52b collides with the collision part S2 of the diffusion member 51a. Further, the collision part center SC2 is in the virtual dividing plane D2, and the outer periphery of the collision part S2 is set so as not to reach the outer edge part of the diffusing member 51a. The collision portion S2 is a position suitable for the case where the vaporized additive 53 diffuses in the exhaust passage 45 around the collision portion S2 in the virtual dividing plane D2 after the conical spray 54 collides with the collision portion S2. (In this case, it is set to substantially the center in the virtual dividing plane D2.) As shown in FIGS. 2 and 3, the conical spray 54 injected from the injection hole 52b is injected so as to be contained in the collision part S2 when it collides with the collision part S2.

  Since the cover A2 covers the conical spray 54 from the injection hole 52b to the collision part S2 when viewed from the upstream side in the exhaust gas flow direction, the conical spray 54 injected from the injection hole 52b is The exhaust gas flowing in the exhaust passage 45 is prevented from flowing downstream and collides with the collision part S2. The additive that collides with and collides with the collision part S2 is vaporized by the high-temperature exhaust gas, and the vaporized additive 53 diffuses into the exhaust passage 45 around the collision part S2 in the virtual dividing plane D2. As explained above, the conical spray 54 that collided with the colliding portions S1 to S3 becomes finer particles due to the collision and scatters in all directions, so that the conical spray does not collide with the colliding portion. Thus, the additive is more easily vaporized. Accordingly, the distance from the addition valve 21 to the exhaust purification catalyst can be shortened compared to the case where the conical spray does not collide with the collision portion, and thus the increase in the size of the exhaust purification device can be suppressed. it can.

[Diffusion effect of the exhaust emission control device 50 of the first embodiment (FIGS. 4 to 6)]
The diffusion effect of the diffusion member 51a of the exhaust emission control device 50 of the present embodiment will be described in detail with reference to FIGS. FIG. 4 is a diagram for explaining how the additive 53 that collides with the collision portion of the diffusion member 51a is vaporized and diffused in the present embodiment when the flow rate of the exhaust gas is large. FIG. 5 is a diagram for explaining how the additive 53 colliding with the collision part of the diffusion member 51a is vaporized and diffused in the present embodiment when the flow rate of the exhaust gas is small. 6 shows an exhaust emission control device 50 according to the first embodiment, [Example 1 of a conventional exhaust purification device] as a comparative example shown in FIG. 15, and [Conventional exhaust gas as a comparative example shown in FIG. About the example 2 of a purification apparatus], the comparison result which computed the diffusion degree in an exhaust passage using a simple simulation model is shown. The “diffusivity” indicates the degree of diffusion in the radial direction of the additive vaporized in the exhaust passage, and indicates that the larger the diffusion, the more uniformly.

  As shown in FIGS. 4 and 5, the conical spray 54 injected from the injection holes 52a, 52b, 52c (see FIG. 3) of the addition valve 21 is long when viewed from the upstream side in the exhaust gas flow direction. Even if the flow rate of the exhaust gas is large or small, the shape cover portion A1, the cover portions A2 and A3 (see FIGS. 2 and 3) can cause the exhaust gas to flow downstream. Since it is suppressed, it collides with collision part S1, S2, S3, respectively. The additive 53 vaporized by colliding with the collision part S1 mainly diffuses to the virtual dividing surface D1, and the additive 53 vaporized by colliding with the collision part S2 mainly diffuses to the virtual dividing surface D2, and the collision part The additive 53 vaporized by colliding with S3 mainly diffuses to the virtual dividing plane D3. Therefore, the vaporized additive 53 is uniformly vaporized in the radial direction in the exhaust passage 45. The conical spray after colliding with the colliding part is scattered in four directions as fine particles, so it is vaporized and uniformly diffused in the radial direction of the exhaust passage, and the selective catalytic reduction catalyst 43 (see FIG. 1). The distance up to can be made shorter.

  On the other hand, in the case of [Example 1 of the conventional exhaust purification device] shown in FIG. 15, the additive injected from the injection port (corresponding to the injection hole) of the addition valve 121 does not cause any flow of exhaust gas in the exhaust pipe 145. Since there is nothing to block, it is caused to flow downstream by the flow of exhaust gas. When the flow rate of the exhaust gas is small, the additive injected from the injection port reaches the inner wall of the exhaust pipe 145 as the injection destination before vaporization, and the vaporized additive is as shown by a dotted line in FIG. , Concentrated in the lower part of the exhaust pipe 145. In addition, when the flow rate of the exhaust gas is large, the additive injected from the injection port is carried to the flow of exhaust gas at a stroke, so that the vaporized additive is exhausted from the exhaust pipe as shown by a one-dot chain line in FIG. Concentrate upward in 145.

  In the case of [Example 2 of the conventional exhaust purification device] shown in FIG. 16, the dam plate 251 blocks the flow of the exhaust gas, and the cone is formed downstream from the addition valve 221 disposed on the downstream side of the dam plate 251. A spray is injected. When the flow rate of the exhaust gas is large, the injected additive is carried to the flow of exhaust gas from the vicinity of the lower end of the barrier plate 251 at a stretch, so that the vaporized additive is as shown by a one-dot chain line in FIG. , Concentrated in the vicinity of the center in the exhaust pipe 245 (corresponding to the exhaust passage). Further, when the flow rate of the exhaust gas is small, the injected additive reaches the inner wall of the exhaust pipe 245 at the injection destination before being vaporized, and the vaporized additive is indicated by a dotted line in FIG. , Concentrated in the lower part of the exhaust pipe 245.

  As shown in the calculation result by the simple simulation model of FIG. 6, the exhaust purification device 50 of the first embodiment is shown in FIG. 15 [Conventional exhaust purification] regardless of the flow rate of the exhaust gas in the exhaust passage. Compared with [Example 1 of the apparatus] and [Example 2 of the conventional exhaust purification apparatus] shown in FIG. 16, the diffusivity is about twice or more. Further, [Example 1 of the conventional exhaust purification device] and [Example 2 of the conventional exhaust purification device] have a diffusivity when the flow rate of the exhaust gas is larger than that when the flow rate of the exhaust gas is small. Has greatly decreased (the rate of decrease is large). However, in the exhaust purification device 50 of the first embodiment, the conical spray collides with the collision portion regardless of the flow rate of the exhaust gas, so compared with the diffusivity when the flow rate of the exhaust gas is small, Even when the flow rate of the exhaust gas is large, there is no significant decrease in diffusivity.

● [Structure and operation of exhaust emission control device 50 of second embodiment (FIGS. 7 and 8)]
In the exhaust purification device 50 of the second embodiment, the diffusion member 51 in FIG. 1 is the diffusion member 51b, and the exhaust purification device 50 includes the addition valve 21, the diffusion member 51b, and the selective reduction catalyst 43 (not shown). 1). In the second embodiment, as shown in FIGS. 7 and 8, the diffusing member 51b has a spindle cross-sectional shape, and has two collision portions S4 and S5 arranged on the upper left and right. ing. The addition valve 21 causes the conical spray 54 to collide with the two collision portions S4 and S5 from the two nozzle holes 52d and 52e. Hereinafter, differences from the first embodiment will be mainly described. The advantage of the present embodiment is that the diffusion member 51b does not have a long covering portion that covers the upper and lower radial directions of the exhaust passage 45 when viewed from the upstream side in the exhaust gas flow direction. The pressure loss of the exhaust gas in the exhaust passage 45 can be reduced as compared with the diffusion member 51a of the first embodiment.

  As shown in FIG. 8, the addition valve 21 has two injection holes 52 d and 52 e, and the additive is injected in a conical shape from the respective injection holes to form conical sprays 54 that are separated from each other. The respective conical sprays 54 ejected from the respective nozzle holes are ejected so as to directly collide with the respective collision portions S4 and S5 provided on the back surface of the diffusion member 51b.

  As shown in FIG. 7, the diffusion member 51 b is provided upstream of the addition valve 21 in the exhaust passage 45 so as to be orthogonal to the axial direction of the exhaust passage 45. The diffusing member 51b collides with the cover A4 and the nozzle hole 52e that overlap the entire conical spray 54 from the nozzle hole 52d to the collision part S4 when viewed from the upstream side in the exhaust gas flow direction in the exhaust passage 45. Each has a cover portion A5 that overlaps the entire conical spray 54 up to the portion S5. More precisely, when viewed from the upstream side in the exhaust gas flow direction, the cover portions A4 and A5 cover the entire conical spray from the position reaching the exhaust passage 45 to the collision portion. In addition, 2nd Embodiment has shown the example which does not have an elongate cover part. Further, the collision part is at least a part of the downstream surface of the diffusion member 51b in the exhaust gas flow direction.

  In FIG. 8, a cut surface obtained by cutting the exhaust passage 45 along a virtual plane including the back surface of the plate-like diffusion member 51b is defined as a virtual cross section VD2. The center of the virtual cross section VD2 is taken as the center CP. Since the addition valve 21 has two nozzle holes, as shown in FIG. 8, the virtual cross section VD2 is divided into two fan-like virtual dividing surfaces D4 and D5 so as to be substantially equal. That is, in the virtual cross section VD2 in FIG. 8, a center line C1 passing through the center CP and parallel to the Z axis is set, and the right fan shape divided by the center line C1 is defined as the virtual dividing plane D4 and the left fan. The mold is assumed to be a virtual dividing plane D5. The positions of the collision portions S4 and S5 are set so as to correspond to the virtual division surfaces D4 and D5, respectively. The diffusing member 51b has a shape having collision portions S4 and S5.

  Collision portions S4 and S5 indicated by dotted lines are arranged at positions corresponding to the virtual dividing surfaces D4 and D5 in the diffusing member 51b. As shown in FIG. 8, the collision part S4 has a collision part center SC4, and the collision part S5 has a collision part center SC5. When the respective conical sprays 54 reach and collide with the respective collision portions S4 and S5, the central axes of the respective conical sprays pass through the respective collision portion centers SC4 and SC5. Further, as shown in FIGS. 7 and 8, in the virtual cross section VD2 (that is, in the exhaust passage 45), the cover portions A4 and A5 are respectively connected to the conical sprays 54 when viewed from the upstream side in the exhaust gas flow direction. It is provided so that it may overlap. That is, as viewed from the upstream side in the exhaust gas flow direction, each of the conical sprays 54 is entirely covered without protruding from the cover parts A4 and A5.

  As shown in FIG. 8, the cover part A4 and the cover part A5 have positions and shapes that are line-symmetric with respect to the center line C1, and the structure and operation are the same. Therefore, the description of the cover part A5 is omitted. Only the cover A4 will be described. The cover part A4 overlaps with the entire conical spray 54 from the vicinity of the nozzle hole 52d (from the position reaching the exhaust passage 45) to the collision part S4 when viewed from the upstream side in the exhaust gas flow direction. It covers the whole. The conical spray 54 injected from the injection hole 52d collides with the collision part S4 of the diffusion member 51b. Further, the collision part center SC4 is in the virtual dividing plane D4, and the outer periphery of the collision part S4 is set so as not to reach the outer edge part of the diffusing member 51b. The collision part S4 is suitable for the case where the vaporized additive 53 diffuses in the exhaust passage 45 around the collision part S4 in the virtual dividing plane D4 when the conical spray 54 collides with the collision part S4. The position is set (in this case, the upper side in the virtual division plane D4). As shown in FIGS. 7 and 8, the conical spray 54 injected from the injection hole 52d is injected so as to be contained in the collision part S4 when it collides with the collision part S4.

  As for the diffusion effect, as in the first embodiment, the conical spray 54 that reaches the collision portion may be caused to flow downstream by the exhaust gas when viewed from the upstream side in the exhaust gas flow direction. Therefore, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas. The conical spray after colliding with the colliding part is scattered in four directions as fine particles, so it is vaporized and uniformly diffused in the radial direction of the exhaust passage, and the selective catalytic reduction catalyst 43 (see FIG. 1). The distance up to can be made shorter. Further, as in the first embodiment, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas, so the flow rate of the exhaust gas is compared with the diffusivity when the flow rate of the exhaust gas is small. Decrease in diffusivity when is large is also suppressed.

[Structure and operation of the exhaust emission control device 50 of the third embodiment (FIGS. 9 and 10)]
In the exhaust purification device 50 of the third embodiment, the diffusion member 51 in FIG. 1 is the diffusion member 51c, and the exhaust purification device 50 includes the addition valve 21, the diffusion member 51c, and the selective reduction catalyst 43 (not shown). 1). In the third embodiment, the diffusing member 51c has an I-shape as shown in FIGS. 9 and 10, and has two collision portions S6 and S7 arranged at the top and bottom of the center. ing. The addition valve 21 causes the conical spray 54 to collide with the two collision portions S6 and S7 from the two nozzle holes 52f and 52g. Hereinafter, differences from the first embodiment will be mainly described. The advantage of the present embodiment is that the diffusion member 51c covers only the upper and lower radial directions in the exhaust passage 45 when viewed from the upstream side in the exhaust gas flow direction, and the diffusion of the first embodiment. Compared with the member 51 a, the vaporized additive is uniformly diffused vertically in the exhaust passage 45 while reducing the pressure loss of the exhaust gas in the exhaust passage 45.

  As shown in FIG. 10, the addition valve 21 has two injection holes 52 f and 52 g, and the additive is injected in a conical shape from the respective injection holes to form separated conical sprays 54. The respective conical sprays 54 ejected from the respective nozzle holes are ejected so as to directly collide with the respective collision portions S6 and S7 provided on the back surface of the diffusion member 51c.

  As shown in FIG. 9, the diffusion member 51 c is provided on the upstream side of the addition valve 21 in the exhaust passage 45 so as to be orthogonal to the axial direction of the exhaust passage 45. The diffusing member 51c has an elongated covering portion A6 that overlaps the entire conical spray 54 from the vicinity of the nozzle hole 52f to the collision portion S6 when viewed from the upstream side in the exhaust gas flow direction in the exhaust passage 45. Each has a long covering portion A7 that overlaps the entire conical spray 54 from the vicinity of the nozzle hole 52g to the collision portion S7. In addition, in the example shown in FIG.9 and FIG.10, elongate cover part A6 is also a part of elongate cover part A7. More precisely, when viewed from the upstream side in the exhaust gas flow direction, the long covering portions A6 and A7 cover the entire conical spray from the position reaching the exhaust passage 45 to the collision portion. Yes. In addition, 3rd Embodiment has shown the example whose at least 1 cover part (in this case, code | symbol A6, A7) is a elongate cover part. The collision part is at least a part of the downstream surface of the diffusion member 51c in the exhaust gas flow direction.

  In FIG. 10, a cut surface obtained by cutting the exhaust passage 45 along a virtual plane including the back surface of the plate-like diffusion member 51c is defined as a virtual cross section VD3. The center of the virtual cross section VD3 is taken as the center CP. Since the addition valve 21 has two nozzle holes, as shown in FIG. 10, the virtual cross section VD3 is divided into two fan-like virtual dividing surfaces D6 and D7 so as to be substantially equal. That is, in the virtual cross section VD3 in FIG. 10, a center line C1 passing through the center CP and parallel to the Z axis is set, a center line C2 passing through the center CP and parallel to the Y axis is set, and the center line C2 The divided upper sector is defined as a virtual division plane D6, and the lower sector is defined as a virtual division plane D7. And the position of collision part S6, S7 is set corresponding to each of the virtual division surfaces D6, D7. The diffusing member 51c has a shape having collision portions S6 and S7.

  Collision portions S6 and S7 indicated by dotted lines are arranged at positions corresponding to the virtual dividing surfaces D6 and D7 in the diffusing member 51c. As shown in FIG. 10, the collision part S6 has a collision part center SC6, and the collision part S7 has a collision part center SC7, respectively. When the respective conical sprays 54 reach and collide with the respective collision portions S6 and S7, the central axes of the respective conical sprays pass through the respective collision portion centers SC6 and SC7. Further, as shown in FIGS. 9 and 10, in the virtual cross section VD3 (that is, in the exhaust passage 45), when viewed from the upstream side in the flow direction of the exhaust gas, the long covering portions A6 and A7 are conical. It is provided so as to overlap with the spray 54. That is, as viewed from the upstream side in the exhaust gas flow direction, each of the conical sprays 54 is entirely covered without protruding from the long covering portions A6 and A7.

  As shown in FIG. 10, the long covering portion A6 has a long shape extending downward from the upper end (near the injection hole 52f) of the diffusion member 51c. The long covering portion A6 is viewed from the upstream side in the exhaust gas flow direction, and the conical spray 54 from the vicinity of the nozzle hole 52f (from the position reaching the exhaust passage 45) to the collision portion S6. It overlaps with the whole and covers the whole. The long covering portion A6 is an upper half region obtained by dividing the diffusing member 51c along the center line C2. In FIG. 10, the direction perpendicular to both the longitudinal direction of the long cover portion A6 and the axial direction of the exhaust passage 45 (that is, the left-right direction in FIG. 10) is defined as the long portion width direction, and the long cover is formed. The length of the long portion width direction of the portion A6 is defined as a long portion width W2. Further, when the conical spray 54 sprayed from the nozzle hole 52f reaches the collision portion S6 of the long covering portion A6, the length of the conical spray 54 in the width direction of the long portion is the conical spray width L2. And In this case, the cone spreading angle θ2 of the conical spray 54 injected toward the collision part S6 is set to an angle at which the conical spray width L2 is shorter than the long part width W2. Further, the collision part center SC6 is on the center line C1, and the collision part S6 is set so that the outer periphery of the collision part S6 does not cover the outer edge of the diffusion member 51c. When the conical spray 54 collides with the collision portion S6, the collision portion S6 is located at a position where the vaporized additive is evenly diffused in the virtual division surface D6 (that is, substantially in the center of the virtual division surface D6). Is set. As shown in FIGS. 9 and 10, the conical spray 54 injected from the injection hole 52f is injected so as to be contained in the collision part S6 when colliding with the collision part S6. Thus, the addition valve 21 has a width (conical spray width L2) of the conical spray injected into the exhaust passage (conical spray corresponding to the collision portion S6) (width of the long cover A6) (long). The additive is sprayed at a narrow angle so as to be narrower than the scale portion width W2).

  As shown in FIG. 10, the long covering portion A7 has a long shape extending downward from the upper end of the diffusion member 51c (in the vicinity of the injection hole 52g). The long covering portion A7 is viewed from the upstream side in the flow direction of the exhaust gas, and the conical spray 54 from the vicinity of the nozzle hole 52g (from the position reaching the exhaust passage 45) to the collision portion S7. It overlaps with the whole and covers the whole. In the example of FIGS. 9 and 10, the long cover portion A <b> 7 includes a long cover portion A <b> 6. That is, the long covering portion A7 is the entire region from the upper end to the lower end of the diffusing member 51c. In FIG. 10, the length of the conical spray 54 in the width direction of the long portion when the conical spray 54 injected from the injection hole 52g reaches the collision portion S7 of the long covering portion A7 is the conical spray. The width is L3. In this case, the cone spread angle θ3 of the conical spray 54 injected toward the collision portion S7 is set to a narrow angle at which the conical spray width L3 is narrower than the long portion width W2. Further, the collision part center SC7 is on the center line C1, and the collision part S7 is set so that the outer periphery of the collision part S7 does not cover the outer edge of the diffusing member 51c. The collision part S7 is a position where the vaporized additive 53 is evenly diffused in the virtual division surface D7 when the conical spray 54 collides with the collision part S7 (that is, approximately the center in the virtual division surface D7). Is set to As shown in FIGS. 9 and 10, the conical spray 54 injected from the injection hole 52g is injected so as to be contained in the collision part S7 when colliding with the collision part S7. In this way, the addition valve 21 has a width (conical spray width L3) of the conical spray injected into the exhaust passage (conical spray corresponding to the collision portion S7) (width of the long covering portion A7). The additive is sprayed at a narrow angle so as to be narrower than the scale portion width W2).

  As for the diffusion effect, as in the first embodiment, the conical spray 54 that reaches the collision portion may be caused to flow downstream by the exhaust gas when viewed from the upstream side in the exhaust gas flow direction. Therefore, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas. The conical spray after colliding with the colliding part is scattered in four directions as fine particles, so it is vaporized and uniformly diffused in the radial direction of the exhaust passage, and the selective catalytic reduction catalyst 43 (see FIG. 1). The distance up to can be made shorter. Further, as in the first embodiment, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas, so the flow rate of the exhaust gas is compared with the diffusivity when the flow rate of the exhaust gas is small. Decrease in diffusivity when is large is also suppressed.

[Structure and operation of the exhaust emission control device 50 of the fourth embodiment (FIGS. 11 and 12)]
In the exhaust purification device 50 of the fourth embodiment, the diffusion member 51 in FIG. 1 is a diffusion member 51d, and the exhaust purification device 50 includes an addition valve 21, a diffusion member 51d, and a selective reduction catalyst 43 (not shown). 1). In the fourth embodiment, as shown in FIGS. 11 and 12, the diffusing member 51d has an inverted V-shape and has two collision portions S8 and S9 arranged on the left and right sides of the center. doing. The addition valve 21 causes the conical spray 54 to collide with the two collision portions S8 and S9 from the two nozzle holes 52h and 52i. Hereinafter, differences from the first embodiment will be mainly described. The advantage of this embodiment is that the diffusion member 51d is opened without covering the central lower part in the exhaust passage 45, and is covered only in a long shape on the left and right, as viewed from the upstream side in the exhaust gas flow direction. Therefore, as compared with the diffusing member 51 a of the first embodiment, the vaporized additive 53 is uniformly distributed vertically in the exhaust passage 45 while reducing the pressure loss of the exhaust gas in the exhaust passage 45. To be diffused.

  As shown in FIG. 12, the addition valve 21 has two injection holes 52 h and 52 i, and the additive is injected in a conical shape from the respective injection holes to form separated conical sprays 54, respectively. The respective conical sprays 54 ejected from the respective nozzle holes are ejected so as to directly collide with the respective collision portions S8 and S9 provided on the back surface of the diffusion member 51d.

  As shown in FIG. 11, the diffusion member 51 d is provided on the upstream side of the addition valve 21 in the exhaust passage 45 so as to be orthogonal to the axial direction of the exhaust passage 45. The diffusing member 51d has a long covering portion A8 that overlaps the entire conical spray 54 from the vicinity of the injection hole 52h to the collision portion S8 when viewed from the upstream side in the exhaust gas flow direction in the exhaust passage 45. Each has a long covering portion A9 that overlaps the entire conical spray 54 from the vicinity of the nozzle hole 52i to the collision portion S9. More precisely, when viewed from the upstream side in the exhaust gas flow direction, the long covering portions A8 and A9 cover the entire conical spray from the position reaching the exhaust passage 45 to the collision portion. Yes. In addition, 4th Embodiment has shown the example whose at least 1 cover part (in this case, code | symbol A8, A9) is a elongate cover part. Further, the collision part is at least a part of the surface of the diffusion member 51d on the downstream side in the exhaust gas flow direction.

  In FIG. 12, a cut surface obtained by cutting the exhaust passage 45 in a virtual plane including the back surface of the plate-like diffusion member 51d is defined as a virtual cross section VD4. The center of the virtual cross section VD4 is defined as the center CP. Since the addition valve 21 has two nozzle holes, as shown in FIG. 12, the virtual cross section VD4 is divided into two fan-like virtual dividing surfaces D8 and D9 so as to be substantially equal. That is, in the virtual cross section VD4 in FIG. 12, a center line C1 that passes through the center CP and is parallel to the Z axis is set, and the left and right fan shapes divided by the center line C1 are defined as the virtual dividing plane D8 and the virtual dividing plane D9. And The positions of the collision portions S8 and S9 are set so as to correspond to the virtual division surfaces D8 and D9, respectively. The diffusing member 51d has a shape having collision portions S8 and S9.

  Collision portions S8 and S9 indicated by dotted lines are arranged at positions corresponding to the virtual dividing surfaces D8 and D9 in the diffusing member 51d. As shown in FIG. 12, the collision part S8 has a collision part center SC8, and the collision part S9 has a collision part center SC9. When the respective conical sprays 54 reach and collide with the respective collision portions S8 and S9, the central axes of the respective conical sprays pass through the respective collision portion centers SC8 and SC9. Further, as shown in FIGS. 11 and 12, in the virtual cross section VD4 (that is, in the exhaust passage 45), when viewed from the upstream side in the exhaust gas flow direction, the long covering portions A8 and A9 are conical. It is provided so as to overlap with the spray 54. That is, as viewed from the upstream side in the exhaust gas flow direction, each of the conical sprays 54 is entirely covered without protruding from the long covering portions A8 and A9.

  The long covering portion A8 and the long covering portion A9 have positions and shapes that are line-symmetric with respect to the center line C1, and the structure and operation are the same. Therefore, the long covering portion A9 is described. Only the elongated covering portion A8 will be described. As shown in FIG. 12, the long covering portion A8 has a long shape extending downward from the vicinity of the injection hole 52h. The long covering portion A8 is viewed from the upstream side in the flow direction of the exhaust gas, and the conical spray 54 from the vicinity of the nozzle hole 52h (from the position reaching the exhaust passage 45) to the collision portion S8. It overlaps with the whole and covers the whole. In FIG. 12, the direction perpendicular to both the longitudinal direction of the long covering portion A8 and the axial direction of the exhaust passage 45 is defined as the long portion width direction, and the long covering portion A8 has a widthwise direction. The length is defined as a long portion width W4. Further, when the conical spray 54 sprayed from the nozzle hole 52h reaches the collision portion S8 of the long covering portion A8, the length of the long portion width direction of the conical spray 54 is defined as the conical spray width L4. And In this case, the cone spreading angle θ4 of the conical spray 54 injected toward the collision portion S8 is set to a narrow angle at which the conical spray width L4 is narrower than the long portion width W4. Further, the collision part center SC8 is positioned substantially at the center of the elongated part width W4, and the collision part S8 is set so that the outer periphery of the collision part S8 does not cover the outer edge part of the diffusion member 51d. The collision portion S8 is a position where the vaporized additive 53 is evenly diffused in the virtual division surface D8 when the conical spray 54 collides with the collision portion S8 (that is, approximately the center in the virtual division surface D8). Is set to As shown in FIGS. 11 and 12, the conical spray 54 injected from the injection hole 52h is injected so as to be contained in the collision part S8 when it collides with the collision part S8. In this way, the addition valve 21 has a width (conical spray width L4) of the conical spray injected into the exhaust passage (conical spray corresponding to the collision portion S8) that is the width (long) of the long covering portion A8. The additive is injected at a narrow angle so as to be narrower than the scale portion width W4).

  As for the diffusion effect, as in the first embodiment, the conical spray 54 that reaches the collision portion may be caused to flow downstream by the exhaust gas when viewed from the upstream side in the exhaust gas flow direction. Therefore, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas. The conical spray after colliding with the colliding part is scattered in four directions as fine particles, so it is vaporized and uniformly diffused in the radial direction of the exhaust passage, and the selective reduction catalyst 43 (see FIG. 1). The distance up to can be made shorter. Further, as in the first embodiment, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas, so the flow rate of the exhaust gas is compared with the diffusivity when the flow rate of the exhaust gas is small. Decrease in diffusivity when is large is also suppressed.

● [Structure and operation of exhaust emission control device 50 of the fifth embodiment (FIG. 13)]
As shown in FIG. 13, the exhaust emission control device 50 according to the fifth embodiment has the diffusion member 51 (51 a to 51 d) described in the first to fourth embodiments in the axial direction of the exhaust passage 45. Rather than being arranged so as to be orthogonal to each other, the virtual cross section including the back surface of the diffusion member is arranged so as to be orthogonal to the central axis 21J of the addition valve 21. For example, the center CP of the virtual cross section is arranged on the central axis 21J, and the diffusion member is arranged so that the virtual cross section and the central axis 21J are orthogonal to each other. In FIG. 13, the diffusing member 51 is tilted so that the angle θz formed by the axial direction of the exhaust passage and the diffusing member 51 is 0 [degree] <angle θz <90 [degree]. Also good. In the first to fourth embodiments, since the conical spray 54 collides with the collision portion from obliquely upward, the conical spray after the collision is scattered more downward than above. However, in the present embodiment, since the conical spray collides with the collision portion from almost the front, the conical spray after the collision is scattered almost uniformly upward and downward, and depends on the radial direction in the exhaust passage 45. Uniformly diffused.

  As for the diffusion effect, as in the first embodiment, the conical spray 54 that reaches the collision portion may be caused to flow downstream by the exhaust gas when viewed from the upstream side in the exhaust gas flow direction. Therefore, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas. The conical spray after colliding with the colliding part is scattered in four directions as fine particles, so it is vaporized and uniformly diffused in the radial direction of the exhaust passage, and the selective reduction catalyst 43 (see FIG. 1). The distance up to can be made shorter. Further, as in the first embodiment, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas, so the flow rate of the exhaust gas is compared with the diffusivity when the flow rate of the exhaust gas is small. Decrease in diffusivity when is large is also suppressed.

[Structure and operation of exhaust purification device 50 of sixth embodiment (FIG. 14)]
As shown in FIG. 14, the exhaust purification apparatus 50 of the sixth embodiment arranges the two addition valves 21 on the left and right (or the upper left and right) of the exhaust passage 45 and exhausts the two diffusion members 51z. It arrange | positions in the right and left (or upper right and left) in the channel | path 45, and makes the conical spray 54 collide with the collision part of each diffusion member from each addition valve. In this case, the diffusion member 51z may be disposed so as to be orthogonal to the axial direction of the exhaust passage 45, or may be disposed so as to be orthogonal to the central axis of the corresponding addition valve. By separating the addition valve and diffusion member on the left and right, when the collision part is set to the left and right, it is easy to minimize the area of the diffusion member with respect to the collision part, and to further reduce the pressure loss of the exhaust gas This is an advantage.

  As for the diffusion effect, as in the first embodiment, the conical spray 54 that reaches the collision portion may be caused to flow downstream by the exhaust gas when viewed from the upstream side in the exhaust gas flow direction. Therefore, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas. Then, the conical spray after colliding with the colliding part is scattered in four directions as fine particles, so that it is vaporized and uniformly diffused in the radial direction of the exhaust passage 45, and the selective reduction catalyst 43 (see FIG. 1). ) Can be made shorter. Further, as in the first embodiment, the conical spray collides with the collision part regardless of the flow rate of the exhaust gas, so the flow rate of the exhaust gas is compared with the diffusivity when the flow rate of the exhaust gas is small. Decrease in diffusivity when is large is also suppressed.

● [Method of arranging diffusion member 51 in exhaust passage, etc.]
Hereinafter, an example of a method of arranging (fixing) the diffusion member 51 in the exhaust passage 45 will be described. For example, the exhaust pipe of the exhaust passage 45 is cut along the virtual cross section (VD1 to VD4), and flange portions are provided on the cut surfaces of the upstream and downstream exhaust pipes. A diffusion member 51 is sandwiched between the flange portion of the downstream exhaust pipe and the exhaust pipe is connected.
Alternatively, the diffusion member 51 is inserted from the opening of the exhaust pipe, and a welding tool is inserted from the opening to weld the diffusion member 51.

  In the first to sixth embodiments, the plate-like diffusion member 51 is disposed in the exhaust passage 45, but without using the diffusion member 51 separate from the exhaust passage 45, upstream of the addition valve. The side exhaust passage 45 may be recessed downward to form a collision portion. That is, in the exhaust passage 45 on the upstream side of the addition valve, an exhaust passage recess that protrudes downward from the upper end is formed, and the impact valve is provided in the exhaust passage recess with a flat surface on the side of the addition valve. A conical spray may be sprayed from the addition valve to the part.

● [Effect of this application]
In the embodiment described above, the additive is injected upstream from the addition valve toward the diffusion member disposed upstream in the exhaust passage. As viewed from the upstream side in the exhaust gas flow direction, the entire conical spray from the injection valve nozzle hole to the collision part is covered by the covering part of the diffusion member. Therefore, the entire conical spray from the nozzle hole of the addition valve to the collision part directly collides with the collision part of the diffusion member regardless of the flow rate of the exhaust gas. Then, the conical spray that collides with the collision part is scattered and vaporized in various directions, and is uniformly diffused in the radial direction in the exhaust passage, and the distance to the selective reduction catalyst 43 (see FIG. 1) is further increased. Can be shortened. The diffusion member 51 only needs to be disposed so as to intersect the axial direction of the exhaust passage 45, and is disposed so as to be orthogonal to the axial direction of the exhaust passage 45 (see the first to fourth embodiments). Or may be arranged so as to be inclined at an angle different from orthogonal to the axial direction of the exhaust passage 45 (see the fifth embodiment).

  The exhaust emission control device of the present invention is not limited to the configuration, structure, shape and the like described in the present embodiment, and various modifications, additions and deletions can be made without changing the gist of the present invention.

  The shape of the diffusing member and the number and position of the collision parts are not limited to the shape of the diffusing member and the number and position of the collision parts described in the first to fourth embodiments. Moreover, you may arrange | position the diffusion member demonstrated in the 1st-4th embodiment like 5th, 6th embodiment.

  The exhaust purification apparatus described in the present embodiment has been described by taking a selective reduction catalyst (urea SCR) as an example and urea water as an example of an additive, but DPF as a selective purification catalyst, fuel as an additive, The present invention can be applied to various selective purification catalysts and additives corresponding to the selective purification catalyst.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 11 Intake path 12 Exhaust path 21, 21a, 21b Addition valve 21J Center axis 22 Additive tank 23 Pump 25 Controller 26 Pressure detection means 31 Intake air flow rate detection means 32 NOx detection means 33 Accelerator opening degree detection means 34 Rotation Detection means 41 Oxidation catalyst 42 Filter 43 Selective reduction catalyst (exhaust purification catalyst)
44 Oxidation catalyst 45 Exhaust passage 50 Exhaust purification device 51, 51a, 51b, 51c, 51d, 51z Diffusion member 52a, 52b, 52c, 52d, 52e Injection hole 52f, 52g, 52h, 52i Injection hole 53 Additive (reducing agent)
54 Conical spray 100, 200 Exhaust purification device 121 Addition valve 143, 243 Selective purification catalyst 145, 245 Exhaust pipe (exhaust passage)
221 Reducing agent addition device 251 Weir plate A1, A6, A7, A8, A9 Long covering part A2, A3, A4, A5 Covering part C1, C2 Center line CP center D1, D2, D3 Virtual dividing plane D4, D5, D6 Virtual dividing surface D7, D8, D9 Virtual dividing surface H1 Piping H2 Discharge piping L1, L2, L3, L4 Conical spray width S1, S2, S3, S4, S5, S6, S7, S8, S9 Colliding part SC1, SC2 , SC3, SC4, SC5 Collision center SC6, SC7, SC8, SC9 Collision center W1, W2, W4, W5 Long part width θ1, θ2, θ3, θ4 Cone spread angle θz angle VD1, VD2, VD3, VD4 virtual cross section

Claims (3)

An exhaust purification catalyst provided in the exhaust passage of the internal combustion engine;
An addition valve for injecting an additive into the exhaust passage upstream of the exhaust purification catalyst in the exhaust gas flow direction;
The spraying of the additive injected from the addition valve is provided in the exhaust passage upstream of the addition valve in the flow direction of the exhaust gas and partially blocks the flow of the exhaust gas in the exhaust passage. A plate-like diffusion member that collides and diffuses the additive into the exhaust passage;
An exhaust purification device comprising:
The additive valve injects the additive toward the upstream side in the flow direction of the exhaust gas so that the spray of the additive collides with the back side of the diffusion member,
The diffusion member includes a collision portion that collides with the spray of additive injected from the addition valve, and the spray of additive injected from the addition valve when the diffusion member is viewed from the upstream side in the exhaust gas flow direction. A cover portion provided so as to overlap,
Exhaust purification device. The exhaust emission control device according to claim 1,
The additive valve has a plurality of injection holes and injects the additive such that the additive injected from each of the plurality of injection holes forms a spray of the plurality of additives that are separated from each other in the exhaust passage. And
The diffusion member has the collision portion and the cover portion respectively corresponding to the sprays of a plurality of additives injected from the addition valve.
Exhaust purification device. The exhaust emission control device according to claim 1 or 2,
At least one of the cover portions is a long cover portion having a long shape,
The additive spray injected from the addition valve forms a conical spray,
The additive valve injects the additive at a narrow angle so that the width of the conical spray of the additive injected into the exhaust passage is narrower than the width of the elongated cover portion;
Exhaust purification device.

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