Exhaust gas treatment device

Abstract

To provide an exhaust gas treatment device capable of efficiently promoting evaporation and decomposition of a reducing agent.SOLUTION: An exhaust gas treatment device reduces nitrogen oxide included in exhaust gas by mixing exhaust gas discharged from an internal combustion engine with a reducing agent. The exhaust gas treatment device includes: a chamber that has a cylindrical wall extending in a cylinder axial direction and in which an introduction port for introducing the exhaust gas is opened at one side end in the cylinder axial direction and the other side end in the cylinder axial direction is closed; a pipe that has a pipe circumferential wall extending in a pipe axial direction, is surrounded by the cylindrical wall from the outer side and disposed so that a circumferential space is formed between the cylindrical wall and the pipe circumferential wall and has an inlet opened at one side portion of a pipe axis and an outlet opened at the other side portion of the pipe axis and located outside the chamber; an injector that injects the reducing agent toward the circumferential space; and a guide plate that guides the exhaust gas and the injected reducing agent from the circumferential space side to the inlet side.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to exhaust treatment devices. [Background technology]

[0002] There are known exhaust treatment devices that treat particulate matter (PM) and nitrogen oxides (NOx) contained in exhaust emitted from internal combustion engines. For example, an exhaust treatment device that reduces the nitrogen oxides contained in exhaust by mixing the exhaust with urea water as a reducing agent is called a urea selective catalytic reduction (SCR) device.

[0003] Patent Document 1 discloses an exhaust gas purification device for an engine, which includes an exhaust passage drawn from the combustion chamber of the engine, a reducing agent injector that injects a reducing agent into exhaust gas inside the exhaust passage, a reducing catalyst body that purifies nitrogen oxides in the exhaust gas with a reducing agent or a substance generated from the reducing agent, an impactor that separates the inside of the exhaust passage into an inner first space and an outer second space by a cylindrical partition wall, and a mixer that is arranged between the impactor and the reducing catalyst body and has a protruding piece that protrudes inward from the inner surface of the exhaust passage, and the reducing agent is injected by the reducing agent injector toward an injection target portion set on the surface of the partition wall facing the first space.

[0004] Patent Document 2 also discloses a reducing agent thermal decomposition system for a selective catalytic reduction device, which includes: an elbow duct that is provided in an exhaust duct at the front end of a reactor, into which exhaust gas flows and which discharges the flowed-in exhaust gas toward the reactor; an inner pipe unit that is disposed inside the elbow duct and through which a portion of the exhaust gas flows and is discharged; a heating device that is provided in the inner pipe unit and which heats the exhaust gas that has flowed into the inner pipe unit; and a nozzle that is provided in the inner pipe unit and is disposed on the rear end side of the heating device with respect to the flow of the exhaust gas, which injects a reducing agent into the inner pipe unit.

[0005] Patent Document 3 also discloses a nitrogen oxide removal device that includes an exhaust pipe that guides engine exhaust gas to a turbocharger turbine, a dynamic pressure generator that bleeds a portion of the exhaust gas flowing through the exhaust pipe, a reducing agent supplier that mixes the bled gas with a reducing agent and supplies the resulting mixture to the exhaust pipe, and an SCR reactor that is connected to the rear end of the turbocharger turbine and removes nitrogen oxides contained in the exhaust gas through a catalytic reduction reaction using the reducing agent, and the bled gas and reducing agent supplied to the exhaust pipe are sequentially guided to the turbocharger turbine and the SCR reactor through the exhaust pipe. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-123788 [Patent Document 2] Special Publication No. 2016-528424 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-55594 Summary of the Invention [Problem to be solved by the invention]

[0007] In the invention described in Patent Document 1, the impactor is continuously heated by the heat of the exhaust gas passing through the second space outside, thereby accelerating the evaporation and decomposition of the reducing agent injected into the first space. However, there is room for improvement in terms of efficiently accelerating the evaporation and decomposition of the reducing agent.

[0008] In addition, in the invention described in Patent Document 2, the inner pipe is continuously heated by the heat of the exhaust gas passing outside the inner pipe, thereby accelerating the evaporation and decomposition of the reducing agent injected into the inner pipe. However, there is room for improvement in terms of efficiently accelerating the evaporation and decomposition of the reducing agent.

[0009] In addition, in the invention described in Patent Document 3, the porous inner cylinder is continuously heated by the heat of the exhaust gas passing outside the porous inner cylinder, thereby accelerating the evaporation and decomposition of the reducing agent injected into the porous inner cylinder. However, there is room for improvement in terms of efficiently accelerating the evaporation and decomposition of the reducing agent.

[0010] An object of the present disclosure is to provide an exhaust treatment device that can efficiently promote the evaporation and decomposition of a reducing agent. [Means for solving the problem]

[0011] In order to achieve the above object, the exhaust treatment device according to the present disclosure comprises: An exhaust treatment device that reduces nitrogen oxides contained in exhaust gas emitted from an internal combustion engine by mixing the exhaust gas with a reducing agent, a chamber having a cylindrical wall extending in a cylindrical axis direction, with an inlet port for introducing exhaust gas at one end in the cylindrical axis direction and a closed end at the other end in the cylindrical axis direction; a pipe having a pipe peripheral wall extending in a pipe axial direction, the pipe being surrounded from the outside by the cylindrical wall to form a peripheral space between the cylindrical wall and the pipe peripheral wall, the pipe having an inlet opening at one side portion of the pipe axis and an outlet opening at the other side portion of the pipe axis and positioned outside the chamber; an injector that injects the reducing agent toward the circumferential space; a guide plate that guides the exhaust gas and the injected reducing agent from the circumferential space side to the inlet side; Equipped with. [Effects of the Invention]

[0012] According to the present disclosure, the evaporation and decomposition of the reducing agent can be efficiently promoted. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing an example of the layout of a post-processing system according to an embodiment of the present disclosure. [Figure 2]FIG. 2 is a view taken along the arrow A in FIG. [Figure 3] FIG. 3 is a perspective view showing a state in which the exhaust treatment device according to the embodiment of the present disclosure is assembled to a diesel particulate filter. [Figure 4] FIG. 4 is a front view showing a state in which the exhaust treatment device according to the embodiment of the present disclosure is assembled to a diesel particulate filter. [Figure 5] FIG. 5 is a plan view of the exhaust treatment device according to the embodiment of the present disclosure. [Figure 6] FIG. 6 is a front view of the exhaust treatment device according to the embodiment of the present disclosure, as viewed from the exhaust downstream side. [Figure 7] FIG. 7 is a rear view of the exhaust treatment device according to the embodiment of the present disclosure, as viewed from the exhaust upstream side. [Figure 8] FIG. 8 is a right side view of the exhaust treatment device according to the embodiment of the present disclosure. [Figure 9] FIG. 9 is a left side view of the exhaust treatment device according to the embodiment of the present disclosure. [Figure 10] FIG. 10 is a bottom view of the exhaust treatment device according to the embodiment of the present disclosure. [Figure 11] FIG. 11 is a plan view of an exhaust treatment device according to a modified example of the present embodiment. [Figure 12] FIG. 12 is a front view of an exhaust treatment device according to a modified example of this embodiment, as viewed from the exhaust downstream side. [Figure 13] FIG. 13 is a right side view of an exhaust treatment device according to a modified example of the present embodiment. [Figure 14] FIG. 14 is a left side view of an exhaust treatment device according to a modified example of the present embodiment. [Figure 15] FIG. 15 is a bottom view of an exhaust treatment device according to a modified example of the present embodiment. [Figure 16] FIG. 16 is a rear view of an exhaust treatment device according to a modified example of this embodiment, as viewed from the exhaust upstream side. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of the layout of an aftertreatment system according to an embodiment of the present disclosure. FIG. 2 is a view taken along the arrow A in FIG. 1. The aftertreatment system 100A shown in FIGS. 1 and 2 includes a diesel particulate filter (DPF) and a urea selective catalytic reduction (SCR). The layout of the DPF and SCR is determined according to the vehicle model. The DPF collects and removes particulate matter (PM) in the exhaust gas emitted from the internal combustion engine. The aftertreatment system 100A may also include a diesel oxidation catalyst (DOC) disposed upstream of the DPF in the exhaust gas flow to oxidize the fuel (HC) injected after the combustion process, thereby raising the temperature of the exhaust gas and promoting combustion within the DPF.

[0015] The DPF has a cylindrical wall extending in the direction of its cylinder axis, which is the direction extending along a straight line SL1.

[0016] The SCR is located downstream of the DPF and reduces the nitrogen oxides (NOx) contained in the exhaust by mixing the exhaust from which PM has been collected and removed with a reducing agent. Urea water ((NH2)2CO) is used as the reducing agent to be mixed with the exhaust. The urea water is decomposed into ammonia (NH3) by the heat of the exhaust. The ammonia produced by the decomposition of the urea water reduces the nitrogen oxides (NO x Through the above reaction process, nitrogen oxides are reduced to nitrogen (N2) and water (H2O).

[0017] The exhaust treatment device 100 (SCR) in this embodiment has a urea water evaporation chamber, a diffusion chamber, and an SCR catalyst. The layout of the urea water evaporation chamber, the diffusion chamber, and the SCR catalyst is determined according to the vehicle model. Each of the urea water evaporation chamber, the diffusion chamber, and the SCR catalyst has a cylindrical wall and a cylindrical axis.

[0018] The urea water evaporation chamber is positioned so that its cylinder axis CS1 is aligned with a straight line SL1. The diffusion chamber and SCR catalyst are positioned so that their cylinder axes CS2 are aligned with a straight line SL2 that is perpendicular to the straight line SL1. A connecting pipe connects a first pipe located on the urea water evaporation chamber side to a second pipe located on the diffusion chamber side. The urea water evaporation chamber promotes the decomposition of the urea water. The diffusion chamber diffuses ammonia and nitrogen oxides in the exhaust. The SCR catalyst uses hydrocarbons (HC) as a reducing agent. This allows ammonia to selectively react with nitrogen oxides in the exhaust to produce nitrogen and moisture.

[0019] In this embodiment, a urea water evaporation chamber will be described as an example of the exhaust treatment device 100. Fig. 3 is a perspective view showing the exhaust treatment device of this embodiment assembled to the DPF. Fig. 4 is a front view showing the exhaust treatment device of this embodiment assembled to the DPF. Fig. 5 is a plan view of the exhaust treatment device of this embodiment. Fig. 6 is a front view of the exhaust treatment device of this embodiment as seen from the exhaust downstream side. Fig. 7 is a rear view of the exhaust treatment device of this embodiment.

[0020] 3 to 7, the exhaust treatment device 100 includes a urea water evaporation chamber 10 (hereinafter simply referred to as "chamber"), a pipe 20, an injector 30 (see FIG. 4), a reducing agent evaporation plate 40, and a guide plate 50. The pipe 20 corresponds to a first pipe arranged on the chamber 10 (urea water evaporation chamber) side.

[0021] (Chamber 10) The chamber 10 has a cylindrical wall 12 formed, for example, from a stainless steel pipe. In Figures 4 and 7, a partition line PL extending in the vertical direction is indicated by a two-dot chain line. In the following description, the cylinder axis direction may be referred to as the "exhaust direction." One side of the cylinder axis direction may be referred to as the "exhaust upstream side," and the other side of the cylinder axis direction may be referred to as the "exhaust downstream side." A direction perpendicular to the cylinder axis direction may be referred to as the "radial direction." A direction radially away from the cylinder axis CS1 may be referred to as the "radial one side" or the "centrifugal direction," and a direction radially approaching the cylinder axis CS1 may be referred to as the "radial other side" or the "centripetal direction." In Figure 4, which shows the front of the exhaust treatment device 100, the right side may be referred to as the "right side," and the left side may be referred to as the "left side."

[0022] The chamber 10 has a one-side end wall 14 arranged at one end in the axial direction (upstream exhaust side), and an other-side end wall 15 arranged at the other end in the axial direction (downstream exhaust side).

[0023] As shown in Figures 3, 5, and 7, the one-side end wall 14 is divided into two regions: a left side wall 14L located to the left of the partition line PL, and a right side wall 14R located to the right of the partition line PL. In Figure 7, which is a rear view of the exhaust treatment device 100, the left side wall 14L is shown to the right of the partition line PL, and the right side wall 14R is shown to the left of the partition line PL. The one-side end wall 14 is a circular wall that extends radially from the cylindrical axis CS1. An inlet 16 is opened in the one-side end wall 14 for introducing exhaust gas from the DPF (not shown) side. The inlet 16 is an arc-shaped opening that has a predetermined width in the radial direction and extends counterclockwise from the 12 o'clock position to the 6 o'clock position of the circular one-side end wall 14.

[0024] As shown in FIGS. 3 to 6, the other-side end wall 15 is divided into two regions: a left side wall 15L located to the left of the partition line PL, and a right side wall 15R located to the right of the partition line. The other side end wall 15 closes the other end of the chamber 10 in the axial direction (the exhaust downstream side). The left side wall 15L has a wall surface that extends radially from the cylindrical axis CS1 in a substantially semicircular shape. In other words, the wall surface of the left side wall 15L extends counterclockwise from the 12 o'clock position to the 6 o'clock position. The right side wall 15R has a wall surface that extends radially from the cylindrical axis CS1 in a substantially semicircular shape. In other words, the wall surface of the right side wall 15R extends counterclockwise from the 6 o'clock position to the 12 o'clock position. Furthermore, the wall surface of the right side wall 15R is inclined at a predetermined angle θ toward one side in the axial direction (the exhaust upstream side) relative to the wall surface of the left side wall 15L (see FIG. 5).

[0025] The chamber 10 is divided into two spaces: a left chamber portion 10L located to the left of the dividing line PL, and a right chamber portion 10R located to the right of the dividing line PL. The overall length of the left chamber portion 10L in the axial direction is a constant length CL0 (see FIG. 5). In contrast, the overall length of the right chamber portion 10R in the axial direction gradually decreases counterclockwise from the 6 o'clock position to the 3 o'clock position because the wall surface of the right side wall 15R is inclined toward one axial direction side (the exhaust upstream side) with respect to the cylindrical axis CS1. Specifically, the overall length of the right chamber portion 10R in the axial direction decreases from length CL0 to length CL1 (see FIG. 5). As a result, the cross-sectional area of ​​the right chamber portion 10R (the cross-sectional area on a plane perpendicular to the axial direction of the right chamber portion 10R) narrows from the other axial direction side toward one axial direction side.

[0026] (Pipe 20) FIG. 8 is a right side view of an exhaust treatment device according to this embodiment. FIG. 9 is a left side view of an exhaust treatment device according to this embodiment. As shown in FIGS. 3 to 6, 8, and 9, the pipe 20 has a pipe axis PS and a pipe peripheral wall 22 and is formed, for example, from a stainless steel pipe. The pipe axis PS is indicated by a dashed line in FIG. 5. The pipe 20 has a bent portion PS1 bent at the center in the pipe axial direction. A portion PS2 on one side in the pipe axial direction from the bent portion PS1 extends along the cylindrical axis CS1. A portion PS3 on the other side in the pipe axial direction from the bent portion PS1 extends in a direction inclined at a predetermined angle α with respect to the cylindrical axis CS1 (see FIG. 5). The inclination angle α of the other side portion PS3 in the pipe axial direction with respect to the cylindrical axis CS1 is the same as the inclination angle θ of the wall surface of the right side wall 15R with respect to the wall surface of the left side wall 15L (α = θ).

[0027] One axial end of the pipe 20 is a closed end closed by one end wall 14. The other axial end of the pipe 20 is an open end. An inlet 24 is provided in the peripheral pipe wall 22 at one axial end portion PS2. An outlet 26 serving as an open end is provided at the other axial end portion PS3. The outlet 26 is located outside the chamber 10.

[0028] The pipe peripheral wall 22 is disposed so as to be surrounded from the outside by the cylindrical wall 12. As a result, a circumferential space 18 extending circumferentially is formed between the pipe peripheral wall 22 and the cylindrical wall 12. Similar to the chamber 10, which is divided into two spaces by the partition line PL, the circumferential space 18 is divided into two spaces: a left circumferential space 18L (see FIG. 6) located to the left of the partition line PL, and a right circumferential space 18R (see FIG. 6) located to the right of the partition line PL. Similar to the cross-sectional area of ​​the right chamber portion 10R, the cross-sectional area of ​​the right circumferential space 18R narrows from the other side in the cylindrical axis direction toward the one side in the cylindrical axis direction. One side (the exhaust upstream side) of the left circumferential space 18L is connected to the inlet 16. As a result, exhaust gas from the DPF is introduced into the left circumferential space 18L through the inlet 16, and the introduced exhaust gas can move from the left circumferential space 18L to the right circumferential space 18R. Furthermore, the exhaust gas that has moved to the right circumferential space 18R can move from the other side in the axial direction toward one side in the axial direction. In other words, the exhaust gas from the DPF can move from the left circumferential space 18L toward one side in the axial direction of the right circumferential space 18R. The exhaust gas flow direction is indicated by the thick arrow in Figure 3.

[0029] (Injector 30) The injector 30 is disposed in the cylindrical wall 12 of the left chamber portion 10L (see FIG. 4). The nozzle of the injector 30 faces from the cylindrical wall 12 side toward the left circumferential space 18L. This enables the injector 30 to inject a reducing agent (urea water) toward the exhaust gas introduced into the left circumferential space 18L from the inlet 16. In FIG. 4, the flow direction of the exhaust gas is indicated by a hatched arrow, and the flow direction of the reducing agent is indicated by a hollow arrow.

[0030] (reducing agent evaporation plate 40) FIG. 10 is a bottom view of the exhaust treatment device according to this embodiment. As shown in FIGS. 3 to 10, the reducing agent evaporation plate 40 is a flat plate member located within the circumferential space 18 and arranged along the cylindrical wall 12. Specifically, the reducing agent evaporation plate 40 is located between the cylindrical wall 12 and the pipe circumferential wall 22 and extends circumferentially in a counterclockwise direction from the 9 o'clock position to the 4 o'clock position. That is, the reducing agent evaporation plate 40 extends circumferentially from the left circumferential space 18L to the right circumferential space 18R. The reducing agent evaporation plate 40 has an inner wall surface WS1 facing the pipe circumferential wall 22 and an outer wall surface WS2 facing the cylindrical wall 12. The inner wall surface WS1 is positioned so that the reducing agent injected from the injector 30 hits it. Exhaust gas and reducing agent (urea water) flow through the gap between the pipe circumferential wall 22 and the inner wall surface WS1. Exhaust gas flows through the gap between the cylindrical wall 12 and the outer wall surface WS2. As a result, the reducing agent flowing in the gap between the pipe peripheral wall 22 and the inner wall surface WS1 is decomposed into ammonia by the heat of the exhaust gas flowing in the gap between the cylindrical wall 12 and the outer wall surface WS2. Note that the chamber 10 is called a "urea water evaporation chamber" because the reducing agent (urea water) is decomposed into ammonia by the heat of the exhaust gas.

[0031] The total length in the axial direction of the reducing agent evaporator plate 40 in the left circumferential space 18L is a constant length VL0 (see FIG. 10). The total length in the axial direction of the reducing agent evaporator plate 40 in the right circumferential space 18R, like the total length in the axial direction of the right chamber portion 10R, gradually decreases counterclockwise from the 6 o'clock position toward the 4 o'clock position because the wall surface of the right side wall 15R is inclined toward one axial side (exhaust upstream side) with respect to the cylindrical axis CS1. Specifically, the total length in the axial direction of the reducing agent evaporator plate 40 in the right circumferential space 18R decreases from length VL0 to length VL1 (see FIG. 10).

[0032] (Signboard 50) The guide plate 50 is bent at a central portion 51 in the axial direction, similar to the pipe 20 that is bent at a central portion (bending portion PS1) in the axial direction. The guide plate 50 extends radially from the 12 o'clock position of the pipe circumferential wall 22 to the tubular wall 12, with one radial side connected to the tubular wall 12 and the other radial side connected to the pipe circumferential wall 22. As a result, the guide plate 50 blocks the movement of exhaust gas and ammonia that have moved from the left circumferential space 18L (see FIG. 6) to the right circumferential space 18R (see FIG. 6) so as not to return from the right circumferential space 18R to the left circumferential space 18L. Note that the exhaust gas and ammonia move through the right circumferential space 18R from the other axial side toward the one axial side of the cylinder.

[0033] The guide plate 50 blocks the movement of exhaust gas and ammonia from the right circumferential space 18R to the left circumferential space 18L, while guiding the exhaust gas and ammonia that have moved within the right circumferential space 18R toward one side in the axial direction of the cylinder from the right circumferential space 18R to the inlet 24 side.

[0034] The exhaust gas and ammonia introduced into the inlet 24 enter a position on one side of the pipe 20, move from that position to a position on the other side of the pipe axis, and are discharged outside the chamber 10 through the outlet 26. A diffusion chamber (see FIG. 1) for diffusing the exhaust gas and ammonia is connected to the chamber 10. This causes the ammonia to react with nitrogen oxides in the exhaust gas, and in the reaction process, the nitrogen oxides are reduced to nitrogen and moisture.

[0035] The exhaust treatment device 100 in the above embodiment is an exhaust treatment device that reduces nitrogen oxides contained in exhaust emitted from an internal combustion engine by mixing the exhaust with a reducing agent, and is equipped with: a chamber 10 having a cylindrical wall 12 and a cylindrical axis CS1, with an inlet 16 for introducing exhaust gas at one end in the cylindrical axis direction and a closed other end in the cylindrical axis direction; a pipe 20 having a pipe peripheral wall 22 and a pipe axis PS, and being surrounded from the outside by the cylindrical wall 12 to form a circumferential space 18 that extends circumferentially along the cylindrical wall 12; an inlet 24 opened at one side portion of the pipe axis; and an outlet 26 opened at the other side portion of the pipe axis and positioned outside the chamber; an injector 30 that injects reducing agent from the cylindrical wall 12 side toward the circumferential space 18; and a guide plate 50 that guides the exhaust gas and the injected reducing agent from the circumferential space 18 side toward the inlet 24.

[0036] With the above configuration, the exhaust gas flows along the outer periphery of the pipe 20. The entire peripheral wall 22 of the pipe 20 can be efficiently heated by the heat from the exhaust gas flowing along the outer periphery of the pipe, which makes it possible to efficiently promote the evaporation and decomposition of the reducing agent passing through the inside of the pipe 20.

[0037] The exhaust treatment device 100 in the above embodiment further includes a reducing agent evaporation plate 40 that is located within the circumferential space 18 and is arranged so that the injected reducing agent hits it, and the guide plate 50 guides the exhaust gas and the reducing agent that has evaporated by hitting the reducing agent evaporation plate 40 from the circumferential space 18 side to the inlet 24 side. As a result, the reducing agent evaporation plate 40 is arranged so that the reducing agent hits the reducing agent evaporation plate 40, making it possible to promote the evaporation and decomposition of the reducing agent even more efficiently.

[0038] In the exhaust treatment device 100 in the above embodiment, the reducing agent evaporation plate 40 is disposed so as to follow the cylindrical wall 12. This allows the area of ​​the reducing agent evaporation plate 40 to expand along the cylindrical wall 12, and the evaporation and decomposition of the reducing agent is promoted in accordance with the expanded area, making it possible to sufficiently perform the evaporation and decomposition of the reducing agent.

[0039] In the exhaust treatment device 100 of the above embodiment, one side portion of the pipe axis extends along the cylindrical axis, the inlet 24 is opened in the pipe peripheral wall 22 on one side portion of the pipe axis, and the other side portion of the pipe axis extends in a direction inclined at a predetermined angle with respect to the cylindrical axis. This makes it possible to accommodate layout variations of the exhaust treatment device 100 set for each vehicle model by adjusting the direction in which the other side portion of the pipe axis is inclined.

[0040] In the exhaust treatment device 100 according to the above embodiment, the guide plate 50 extends radially from the pipe peripheral wall 22 to the cylindrical wall 12, with one radial side connected to the cylindrical wall 12 and the other radial side connected to the pipe peripheral wall 22. This makes it possible to guide the reducing agent flowing toward the cylindrical wall 12 side to the pipe peripheral wall 22 side together with the exhaust gas, and further makes it possible to guide the guided reducing agent together with the exhaust gas to the inlet 24 opened in the pipe peripheral wall 22.

[0041] (Variation) Next, an exhaust treatment device 100 according to a modified example of this embodiment will be described with reference to Figs. 11 to 16. Fig. 11 is a plan view of an exhaust treatment device according to a modified example of this embodiment. Fig. 12 is a front view of an exhaust treatment device according to a modified example of this embodiment. Fig. 13 is a right side view of an exhaust treatment device according to a modified example of this embodiment. Fig. 14 is a left side view of an exhaust treatment device according to a modified example of this embodiment. Fig. 15 is a bottom view of an exhaust treatment device according to a modified example of this embodiment. Fig. 16 is a rear view of an exhaust treatment device according to a modified example of this embodiment. In the modified example, configurations that differ from the above-described embodiment will be mainly described, and the same configurations will be assigned the same reference numerals and their description will be omitted.

[0042] In the above embodiment, the inlet 24 of the pipe 20 is opened in the pipe peripheral wall 22 at one axial side portion PS2 of the pipe. In contrast, in the modified examples shown in Figures 11 to 16, the inlet 24A is opened so as to extend from one axial side portion PS2 of the pipe to the other axial side portion PS3 of the pipe. This allows the exhaust gas and reducing agent that have moved from the left chamber portion 10L to the right chamber portion 10R to be introduced into the pipe 20.

[0043] In the above embodiment, the inlet 16 for introducing exhaust gas from the DPF into the chamber 10 is provided in the left side wall 14L, but not in the right side wall 14R. In contrast, in the modified example, the inlet 16 is provided in the left side wall 14L, and an inlet hole 16A for introducing exhaust gas into the chamber 10 is provided in the right side wall 14R. This makes it possible to reduce exhaust gas pressure loss within the chamber 10.

[0044] In the exhaust treatment device 100 in the above embodiment, the chamber 10, the pipe 20, and the guide plate 50 are used as components that make up the SCR, but they may also be used as components that make up other exhaust treatment devices such as a DPF.

[0045] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present disclosure, and the technical scope of the present disclosure should not be interpreted as being limited by these embodiments. In other words, the present disclosure can be carried out in various forms without departing from its gist or main features. [Industrial Applicability]

[0046] The present disclosure is suitably used in vehicles equipped with an exhaust treatment device that is required to efficiently promote the evaporation and decomposition of a reducing agent. [Explanation of symbols]

[0047] CL0 length CL1 length CS1 cylinder shaft CS2 cylinder shaft PL dividing line PS pipe shaft PS1 bending part PS2 Pipe axial direction one side PS3 Other side of pipe in axial direction SL1 Straight Line SL2 straight line VL0 Length VL1 Length WS1 Inner wall WS2 outer wall 10 chambers 10L left chamber 10R right chamber part 12 Cylindrical wall 14 One side end wall 15 Other end wall 15L left side wall 15R right side wall 16 Introduction 16A Introduction hole 18 Circumferential space 18L left circumferential space 18R Right circumferential space 20 Pipe 22 Pipe wall 24 Entrance 24A Entrance 26 Exit 30 injectors 40 Reducing agent evaporation plate 50 Signboard 51 Central part 100 Exhaust treatment device 100A Aftertreatment System

Claims

1. An exhaust treatment device that reduces nitrogen oxides contained in exhaust gas emitted from an internal combustion engine by mixing the exhaust gas with a reducing agent, a chamber having a cylindrical wall extending in a cylindrical axis direction, with an inlet port for introducing exhaust gas at one end in the cylindrical axis direction and a closed end at the other end in the cylindrical axis direction; a pipe having a pipe peripheral wall extending in a pipe axial direction, the pipe being surrounded from the outside by the cylindrical wall to form a peripheral space between the cylindrical wall and the pipe peripheral wall, the pipe having an inlet opening at one side portion of the pipe axis and an outlet opening at the other side portion of the pipe axis and positioned outside the chamber; an injector that injects the reducing agent toward the circumferential space; a guide plate that guides the exhaust gas and the injected reducing agent from the circumferential space side to the inlet side; Equipped with Exhaust treatment device.

2. a reducing agent evaporation plate disposed within the circumferential space so as to be hit by the injected reducing agent, the guide plate guides the exhaust gas and the reducing agent evaporated by hitting the reducing agent evaporation plate from the circumferential space side to the inlet side. The exhaust treatment device according to claim 1 .

3. The reducing agent evaporation plate is disposed along the cylindrical wall. The exhaust treatment device according to claim 2 .

4. a gap is provided between the reducing agent evaporation plate and the cylindrical wall; The exhaust treatment device according to claim 2 .

5. the one side portion of the pipe shaft extends along the cylindrical axis direction, The inlet is opened in the peripheral wall of the pipe at one side of the pipe axis, The other side portion of the pipe axis extends in a direction inclined at a predetermined angle with respect to the cylindrical axis direction. The exhaust treatment device according to claim 1 .

6. The guide plate extends in a radial direction from the pipe peripheral wall to the cylindrical wall, and has one radial side connected to the cylindrical wall and the other radial side connected to the pipe peripheral wall. The exhaust treatment device according to claim 1 .

Images