Exhaust gas treatment device

Abstract

This exhaust gas treatment device reduces nitrogen oxides contained in exhaust gas by mixing the exhaust gas discharged from an internal combustion engine with a reducing agent, and is provided with: a chamber having a cylindrical wall extending in the axial direction of the cylinder and having an introduction port for introducing the exhaust gas, the introduction port being open at one end in the axial direction of the cylinder; the end part of the other side in the cylinder shaft direction is closed; and a tube having a tube peripheral wall extending in the tube axial direction and disposed so as to form a peripheral space between the cylindrical wall and the tube peripheral wall by being surrounded by the cylindrical wall from the outside, the tube further having an inlet provided so as to be open at one side portion of the tube in the tube axial direction, and an outlet provided so as to be open at the other side portion of the tube in the tube axial direction. The outlet is partially opened on the other side of the pipe in the axial direction of the pipe and is positioned on the outer side of the chamber; an injector that injects a reducing agent into 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.

Description

Technical Field

[0001] The present disclosure relates to an exhaust gas treatment device. Background Art

[0002] Exhaust treatment devices are known for treating particulate matter (PM) and nitrogen oxides (NOx) contained in the exhaust gas emitted by internal combustion engines. For example, an exhaust treatment device that reduces NOx by mixing exhaust gas with urea water, 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 comprises: an exhaust passage leading from a combustion chamber of the engine; a reducing agent injector for injecting a reducing agent into the exhaust gas in the exhaust passage; a reducing catalyst body for purifying nitrogen oxides in the exhaust gas using the reducing agent or a substance generated by the reducing agent; an impactor for dividing the space in the exhaust passage into an inner first space and an outer second space by a cylindrical partition wall; and a mixer arranged between the impactor and the reducing catalyst body and having a protruding piece protruding inward from the inner surface of the exhaust passage. In the exhaust gas purification device, the reducing agent injection direction of the reducing agent injector is directed toward an injection target portion set on the surface on the first space side of the partition wall.

[0004] In addition, Patent Document 2 discloses a reducing agent thermal decomposition system for a selective catalytic reduction device, which comprises: a bent pipe, which is arranged in the exhaust duct at the front end of the reactor, for the exhaust gas to flow in and discharge the inflowing exhaust gas to the reactor side; an inner pipe unit, which is arranged inside the bent pipe, for allowing a part of the exhaust gas to flow in and be discharged; a heating device, which is arranged in the inner pipe unit, for heating the exhaust gas flowing into the inner pipe unit; and a nozzle arranged in the inner pipe unit, which is arranged on the rear end side of the heating device based on the exhaust gas flow, and injects the reducing agent into the inner pipe unit.

[0005] In addition, Patent Document 3 discloses a nitrogen oxide removal device, which includes: an exhaust pipe that guides the exhaust gas of the engine to a supercharger turbine; a dynamic pressure generator that extracts a portion of the exhaust gas flowing through the exhaust pipe; a reducing agent supplier that mixes the extracted gas with a reducing agent and supplies the mixed gas to the exhaust pipe; and an SCR reactor that is connected to the rear end of the supercharger turbine and removes nitrogen oxides contained in the exhaust gas by utilizing a catalytic reduction reaction of the reducing agent. In this nitrogen oxide removal device, the extracted gas and the reducing agent supplied to the exhaust pipe flow through the exhaust pipe and are sequentially guided to the supercharger turbine and the SCR reactor.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-123788

[0009] Patent Document 2: Japanese Patent Application No. 2016-528424

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2014-55594 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] In the invention described in Patent Document 1, the impactor is continuously heated by the heat of the exhaust gas flowing through the outer second space, thereby promoting the evaporation and decomposition of the reducing agent injected into the first space. However, there is room for improvement in effectively promoting the evaporation and decomposition of the reducing agent.

[0013] Furthermore, in the invention described in Patent Document 2, the inner tube is continuously heated by the heat of the exhaust gas flowing outside the inner tube, thereby promoting the evaporation and decomposition of the reducing agent injected into the inner tube. However, there is room for improvement in effectively promoting the evaporation and decomposition of the reducing agent.

[0014] Furthermore, in the invention described in Patent Document 3, the porous inner cylinder is continuously heated by the heat of the exhaust gas flowing through the outer surface of the porous inner cylinder, thereby promoting the evaporation and decomposition of the reducing agent injected into the porous inner cylinder. However, there is room for improvement in effectively promoting the evaporation and decomposition of the reducing agent.

[0015] An object of the present disclosure is to provide an exhaust gas treatment device that can effectively promote evaporation and decomposition of a reducing agent.

[0016] Solutions to the Problem

[0017] To achieve the above-mentioned object, the exhaust gas treatment device of the present disclosure reduces nitrogen oxides contained in the exhaust gas by mixing the exhaust gas exhausted from an internal combustion engine with a reducing agent. The exhaust gas treatment device comprises:

[0018] The chamber has a cylindrical wall extending in the axial direction of the cylinder, is open at one end in the axial direction and is provided with an inlet for introducing exhaust gas, and is closed at the other end in the axial direction of the cylinder;

[0019] a tube having a tube peripheral wall extending in a tube axial direction, and being surrounded from the outside by the cylindrical wall so as to form a circumferential space between the cylindrical wall and the tube peripheral wall; the tube further having an inlet and an outlet, the inlet being partially open on one side of the tube in the tube axial direction, and the outlet being partially open on the other side of the tube in the tube axial direction and located outside the chamber;

[0020] an injector for injecting the reducing agent into the peripheral space; and

[0021] The guide plate guides the exhaust gas and the injected reducing agent from the peripheral space side to the inlet side.

[0022] Effects of the Invention

[0023] According to the present disclosure, evaporation and decomposition of the reducing agent can be effectively promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a diagram showing an example of the layout of a post-processing system according to an embodiment of the present disclosure.

[0025] Figure 2 yes Figure 1 A-direction view.

[0026] Figure 3 This 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.

[0027] Figure 4 This is a front view showing a state in which the exhaust treatment device according to the embodiment of the present disclosure is assembled to the diesel particulate filter.

[0028] Figure 5 It is a plan view of the exhaust treatment device according to the embodiment of the present disclosure.

[0029] Figure 6 This is a front view of the exhaust gas treatment device according to the embodiment of the present disclosure as viewed from the exhaust gas downstream side.

[0030] Figure 7 This is a rear view of the exhaust treatment device according to the embodiment of the present disclosure as viewed from the exhaust upstream side.

[0031] Figure 8 It is a right side view of the exhaust treatment device according to the embodiment of the present disclosure.

[0032] Figure 9 It is a left side view of the exhaust treatment device according to the embodiment of the present disclosure.

[0033] Figure 10 It is a bottom view of the exhaust treatment device according to the embodiment of the present disclosure.

[0034] Figure 11 It is a plan view of an exhaust treatment device according to a modified example of the present embodiment.

[0035] Figure 12 This is a front view of an exhaust gas treatment device according to a modified example of the present embodiment as viewed from the exhaust gas downstream side.

[0036] Figure 13It is a right side view of an exhaust treatment device according to a modified example of the present embodiment.

[0037] Figure 14 It is a left side view of an exhaust treatment device according to a modified example of the present embodiment.

[0038] Figure 15 It is a bottom view of an exhaust treatment device according to a modified example of the present embodiment.

[0039] Figure 16 This is a rear view of an exhaust treatment device according to a modified example of the present embodiment as viewed from the exhaust upstream side.

[0040] Description of Reference Numerals

[0041] CL0: length;

[0042] CL1: length;

[0043] CS1: Thru-axle;

[0044] CS2: thru-axle;

[0045] PL: separator line;

[0046] PS: pipe axis;

[0047] PS1: bending part;

[0048] PS2: one side of the tube axis;

[0049] PS3: the other side of the tube axis;

[0050] SL1: straight line;

[0051] SL2: straight line;

[0052] VL0: length;

[0053] VL1: length;

[0054] WS1: medial wall;

[0055] WS2: lateral wall;

[0056] 10: chamber;

[0057] 10L: left ventricular portion;

[0058] 10R: right ventricular portion;

[0059] 12: cylindrical wall;

[0060] 14: one side end wall;

[0061] 15: the other side end wall;

[0062] 15L: left side wall;

[0063] 15R: right side wall;

[0064] 16: import port;

[0065] 16A: lead-in hole;

[0066] 18: Peripheral space;

[0067] 18L: left peripheral space;

[0068] 18R: right periarticular space;

[0069] 20: tube;

[0070] 22: tube wall;

[0071] 24: Entrance;

[0072] 24A: Entrance;

[0073] 26: Export;

[0074] 30: ejector;

[0075] 40: reducing agent evaporation plate;

[0076] 50: guide plate;

[0077] 51: Central Department;

[0078] 100: exhaust treatment device;

[0079] 100A: After-treatment system. DETAILED DESCRIPTION

[0080] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Figure 1 This is a diagram showing an example of the layout of a post-processing system according to an embodiment of the present disclosure. Figure 2 yes Figure 1 A-direction view. Figure 1 and Figure 2 The aftertreatment system 100A shown is equipped with a diesel particulate filter (DPF) and a urea selective catalytic reduction (SCR) device. The placement of the DPF and SCR varies depending on the vehicle model. The DPF captures and removes particulate matter (PM) from the exhaust gas emitted by the internal combustion engine. It should be noted that the aftertreatment system 100A may also include a diesel oxidation catalyst (DOC), which is located on the exhaust upstream side of the DPF and oxidizes the fuel (HC, hydrocarbon) injected after the combustion step to increase the temperature of the exhaust gas, thereby promoting combustion within the DPF.

[0081] The DPF has a cylindrical wall extending along the cylindrical axis direction. The cylindrical axis direction is a direction extending along the straight line SL1.

[0082] The SCR is located downstream of the DPF. It mixes the exhaust gas, after PM has been captured and removed by the DPF, with a reducing agent to reduce nitrogen oxides (NOx). Urea water ((NH2)2CO) is used as the reducing agent mixed with the exhaust. The heat of the exhaust decomposes the urea water into ammonia (NH3). The ammonia generated by the decomposition of the urea water reacts with nitrogen oxides (NOx). Through this reaction, the nitrogen oxides are reduced to nitrogen (N2) and water (H2O).

[0083] The exhaust gas treatment device 100 (SCR) of this embodiment includes a urea-water evaporation chamber, a diffusion chamber, and an SCR catalyst. The placement of these chambers varies depending on the vehicle model. Each chamber has a cylindrical wall and a cylindrical axis.

[0084] The urea-water evaporation chamber is arranged with its cylinder axis CS1 along line SL1. The diffusion chamber and SCR catalyst are arranged so that their cylinder axes CS2 lie on line SL2, perpendicular to line SL1. A first tube located on the urea-water evaporation chamber side and a second tube located on the diffusion chamber side are connected by a connecting tube. The urea-water evaporation chamber promotes the decomposition of urea-water. The diffusion chamber diffuses ammonia and nitrogen oxides in the exhaust gas. The SCR catalyst uses hydrocarbons (HC) as a reducing agent. As a result, ammonia selectively reacts with nitrogen oxides in the exhaust gas to produce nitrogen and water.

[0085] In this embodiment, a urea water evaporation chamber is described as an example of the exhaust treatment device 100 . Figure 3 This is a perspective view showing a state in which the exhaust treatment device according to the present embodiment is assembled to the DPF. Figure 4 This is a front view showing a state in which the exhaust treatment device according to the present embodiment is assembled to the DPF. Figure 5 It is a plan view of the exhaust treatment device according to this embodiment. Figure 6 This is a front view of the exhaust gas treatment device according to the present embodiment as viewed from the exhaust gas downstream side. Figure 7 This is a rear view of the exhaust treatment device according to this embodiment.

[0086] like Figures 3 to 7 As shown, the exhaust gas treatment device 100 includes a urea water evaporation chamber 10 (hereinafter referred to as a "chamber"), a pipe 20, and an injector 30 (see Figure 4 ), the reducing agent evaporation plate 40, and the guide plate 50. It should be noted that the tube 20 corresponds to the first tube arranged on the chamber 10 (urea water evaporation chamber) side.

[0087] (Chamber 10)

[0088] The chamber 10 has a cylindrical wall 12 formed of, for example, a stainless steel pipe. Figure 4 and Figure 7 In the figure, a dividing line PL extending in the up-down direction is represented by a double-dotted line. In the following description, the cylinder axis direction is also referred to as the "exhaust direction". In addition, one side of the cylinder axis direction is also referred to as the "exhaust upstream side", and the other side of the cylinder axis direction is also referred to as the "exhaust downstream side". In addition, the direction perpendicular to the cylinder axis direction is also referred to as the "radial direction". In addition, the direction radially away from the cylinder axis CS1 is also referred to as the "radial side" or the "centrifugal direction", and the direction radially close to the cylinder axis CS1 is also referred to as the "radial other side" or the "centripetal direction". In addition, in the front of the exhaust treatment device 100, Figure 4 The right direction is also referred to as the "right side" and the left direction is also referred to as the "left side".

[0089] The chamber 10 includes a first end wall 14 disposed at one end portion in the cylinder axial direction (exhaust upstream side) and a second end wall 15 disposed at the other end portion in the cylinder axial direction (exhaust downstream side).

[0090] like Figure 3 、 Figure 5 and Figure 7 As shown, one side end wall 14 is divided into two areas: 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. Figure 7 In the figure, the left side wall 14L is shown further to the right of the dividing line PL; the right side wall 14R is shown further to the left of the dividing line PL. The side end wall 14 is a circular wall extending radially about the cylinder axis CS1. An inlet 16 for introducing exhaust gas from the DPF (not shown) is provided in the side end wall 14. The inlet 16 is an arc-shaped opening with a predetermined width in the radial direction, extending counterclockwise from the 12 o'clock position of the circular side end wall 14 to the 6 o'clock position.

[0091] like Figures 3 to 6As shown, the other side end wall 15 is divided into two areas: a left side wall 15L located further to the left than the dividing line PL and a right side wall 15R located further to the right than the dividing line PL. The other side end wall 15 closes the end of the other side of the cylinder axis direction (exhaust downstream side) of the chamber 10. The left side wall 15L has a wall surface that extends radially from the cylinder axis CS1 in a roughly semicircular shape. In other words, the wall surface of the left side wall 15L is a wall surface that 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 cylinder axis CS1 in a roughly semicircular shape. In other words, the wall surface of the right side wall 15R is a wall surface that extends counterclockwise from the 6 o'clock position to the 12 o'clock position. In addition, the wall surface of the right side wall 15R is inclined to one side of the cylinder axis direction (exhaust upstream side) at a predetermined angle θ relative to the wall surface of the left side wall 15L (refer to Figure 5 ).

[0092] The chamber 10 is divided into two spaces: a left chamber portion 10L located to the left of the partition line PL and a right chamber portion 10R located to the right of the partition line PL. The total length of the left chamber portion 10L in the cylindrical axis direction is constant length CL0 (refer to Figure 5 ). In contrast, since the wall surface of the right side wall 15R is inclined toward one side in the cylinder axis direction (exhaust upstream side) relative to the cylinder axis CS1, the total length of the right chamber portion 10R in the cylinder axis direction gradually shortens as it approaches the 3 o'clock position in the counterclockwise direction from the 6 o'clock position. Specifically, the total length of the right chamber portion 10R in the cylinder axis direction shortens from the length CL0 to the length obtained by subtracting the length CL1 (see Figure 5 Thus, the cross-sectional area of the right chamber portion 10R (the cross-sectional area on a plane perpendicular to the cylindrical axis direction of the right chamber portion 10R) narrows from the other side in the cylindrical axis direction to the one side in the cylindrical axis direction.

[0093] (Tube 20)

[0094] Figure 8 It is a right side view of the exhaust treatment device according to this embodiment. Figure 9 : is a left side view of the exhaust gas treatment device of this embodiment. Figures 3 to 6 、 Figure 8 and Figure 9 As shown, the tube 20 has a tube axis PS and a tube peripheral wall 22 and is formed of, for example, a stainless steel tube. Figure 5 The tube axis PS is indicated by a dotted line. The tube 20 has a curved portion PS1 that curves at the center in the tube axis direction. A portion PS2 on the one side of the tube axis direction that is closer to the side of the curved portion PS1 extends along the cylinder axis CS1. A portion PS3 on the other side of the tube axis direction that is closer to the other side of the curved portion PS1 extends in a direction inclined at a predetermined angle α relative to the cylinder axis CS1 (see FIG. 1 ). Figure 5The inclination angle α of the other side portion PS3 in the tube axis direction relative to the cylinder axis CS1 is consistent with the inclination angle θ of the wall surface of the right wall 15R relative to the wall surface of the left wall 15L (α=θ).

[0095] One axial end of the tube 20 is a closed end, enclosed by one end wall 14. The other axial end of the tube 20 is an open end. An inlet 24 is provided in the tube peripheral wall 22 at one axial portion PS2. An outlet 26 is provided at the other axial portion PS3, serving as an open end. Outlet 26 is located outside the chamber 10.

[0096] The tube peripheral wall 22 is arranged to be surrounded from the outside by the cylindrical wall 12. Thus, a circumferentially extending circumferential space 18 is formed between the tube peripheral wall 22 and the cylindrical wall 12. Similar to the chamber 10 divided into two spaces by the partition line PL, the circumferential space 18 is divided into two spaces: a left circumferential space 18L located to the left of the partition line PL (see FIG. 1 ). Figure 6 ) and the right circumferential space 18R located to the right of the partition line PL (see Figure 6 ). In addition, similar to the cross-sectional area of the right chamber portion 10R, the cross-sectional area of the right circumferential space 18R narrows as it approaches one side of the cylinder axis direction from the other side in the cylinder axis direction. One side (exhaust upstream side) of the left circumferential space 18L is connected to the inlet 16. Thus, the exhaust gas from the DPF is introduced into the left circumferential space 18L via the inlet 16, and the introduced exhaust gas can move from the left circumferential space 18L to the right circumferential space 18R. Moreover, the exhaust gas moved to the right circumferential space 18R can move from the other side in the cylinder axis direction to one side in the cylinder axis direction. In other words, the exhaust gas from the DPF can move from the left circumferential space 18L to one side of the cylinder axis direction of the right circumferential space 18R. Figure 3 The thick arrows in the figure indicate the flow direction of the exhaust gas.

[0097] (Injector 30)

[0098] The ejector 30 is disposed on the cylindrical wall 12 (see Figure 4 The ejection port of the injector 30 faces the left circumferential space 18L from the cylindrical wall 12 . Thus, the injector 30 can inject the reducing agent (urea solution) into the exhaust gas introduced into the left circumferential space 18L from the inlet 16 . Figure 4 In the figure, 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.

[0099] (Reducing agent evaporation plate 40)

[0100] Figure 10 FIG is a bottom view of the exhaust gas treatment device of this embodiment. Figures 3 to 10As shown, 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 tube peripheral wall 22 and extends circumferentially from the 9 o'clock position in a counterclockwise direction to the 4 o'clock position. In other words, the reducing agent evaporation plate 40 extends circumferentially from the left circumferential space 18L to the right circumferential space 18R. Furthermore, the reducing agent evaporation plate 40 has an inner wall surface WS1 facing the tube peripheral wall 22 and an outer wall surface WS2 facing the cylindrical wall 12. The inner wall surface WS1 is configured so that the reducing agent injected from the injector 30 contacts the inner wall surface WS1. Exhaust gas and the reducing agent (urea solution) flow through the gap between the tube peripheral 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 through the gap between the tube peripheral wall 22 and the inner wall surface WS1 is decomposed into ammonia by the heat of the exhaust gas flowing through the gap between the cylindrical wall 12 and the outer wall surface WS2. It should be noted that because the chamber 10 utilizes the heat of the exhaust gas to decompose the reducing agent (urea water) into ammonia, it is referred to as a "urea water evaporation chamber."

[0101] The total length of the reducing agent evaporation plate 40 in the cylindrical axis direction in the left peripheral space 18L has a constant length VL0 (see Figure 10 ). Since the wall surface of the right side wall 15R is inclined toward one side in the cylinder axis direction (exhaust upstream side) relative to the cylinder axis CS1, similarly to the full length in the cylinder axis direction in the right chamber portion 10R, the full length in the cylinder axis direction of the reducing agent evaporation plate 40 in the right circumferential space 18R gradually shortens as it approaches the 4 o'clock position in the counterclockwise direction from the 6 o'clock position. Specifically, the full length in the cylinder axis direction of the reducing agent evaporation plate 40 in the right circumferential space 18R shortens from length VL0 to length VL1 (see Figure 10 ).

[0102] (Guide plate 50)

[0103] Similar to the tube 20 that is bent at the center portion (bend portion PS1) in the tube axial direction, the guide plate 50 is bent at the center portion 51 in the tube axial direction. The guide plate 50 extends radially from the 12 o'clock position of the tube peripheral wall 22 to the cylindrical wall 12. One radial side of the guide plate 50 is connected to the cylindrical wall 12, and the other radial side is connected to the tube peripheral wall 22. Thus, the guide plate 50 prevents the left circumferential space 18L (see FIG. 1 ) from being opened. Figure 6 ) moves to the right circumferential space 18R (refer to Figure 6 ) to prevent the exhaust gas and ammonia from returning from the right circumferential space 18R to the left circumferential space 18L. It should be noted that the exhaust gas and ammonia move from the other side in the cylinder axis direction to one side in the cylinder axis direction in the right circumferential space 18R.

[0104] The guide plate 50 prevents exhaust gas and ammonia from moving from the right circumferential space 18R to the left circumferential space 18L, and guides the exhaust gas and ammonia moving toward the cylinder axis in the right circumferential space 18R toward the inlet 24 .

[0105] The exhaust gas and ammonia introduced into the inlet 24 enter a position on one side of the tube axis of the tube 20, move from this position to a position on the other side of the tube axis, and are discharged from the outlet 26 to the outside of the chamber 10. The chamber 10 is connected to a diffusion chamber for diffusing the exhaust gas and ammonia (see Figure 1 ). As a result, ammonia reacts with nitrogen oxides in the exhaust gas, and the nitrogen oxides are reduced to nitrogen and water during the reaction.

[0106] The exhaust gas treatment device 100 in the above-mentioned embodiment is an exhaust gas treatment device that reduces nitrogen oxides contained in the exhaust gas by mixing the exhaust gas discharged from the internal combustion engine with a reducing agent, and comprises: a chamber 10 having a cylindrical wall 12 and a cylindrical axis CS1, which is open at one end in the cylindrical axis direction and is provided with an inlet 16 for introducing the exhaust gas, and is closed at the other end in the cylindrical axis direction; a tube 20 having a tube peripheral wall 22 and a tube axis PS, and is configured to form a circumferential space 18 extending circumferentially along the cylindrical wall 12 by being surrounded by the cylindrical wall 12 from the outside, the tube 20 also having an inlet 24 and an outlet 26, the inlet 24 being provided with a partial opening on one side in the tube axis direction of the tube 20, and the outlet 26 being provided with a partial opening on the other side in the tube axis direction of the tube 20 and being located outside the chamber 10; an injector 30 that injects the reducing agent from the cylindrical wall 12 side into 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 to the inlet 24 side.

[0107] The above structure allows the exhaust gas to flow along the outer circumference of the tube 20. Since the heat from the exhaust gas flowing along the outer circumference of the tube 20 can be effectively used to heat the entire tube peripheral wall 22 of the tube 20, the evaporation and decomposition of the reducing agent passing through the tube 20 can be effectively promoted.

[0108] The exhaust gas treatment device 100 of the above-described embodiment further includes a reducing agent evaporation plate 40. The reducing agent evaporation plate 40 is located within the peripheral space 18 and is arranged so that the injected reducing agent contacts the reducing agent evaporation plate 40. The guide plate 50 guides the exhaust gas and the reducing agent evaporated by contact with the reducing agent evaporation plate 40 from the peripheral space 18 side toward the inlet 24 side. Thus, the reducing agent evaporation plate 40 is arranged so that the reducing agent contacts the reducing agent evaporation plate 40, thereby further effectively promoting the evaporation and decomposition of the reducing agent.

[0109] In the exhaust treatment device 100 of the above-described embodiment, the reducing agent evaporation plate 40 is arranged along the cylindrical wall 12. This allows the area of the reducing agent evaporation plate 40 to be expanded along the cylindrical wall 12, thereby promoting evaporation and decomposition of the reducing agent by an amount corresponding to the expanded area. Consequently, sufficient evaporation and decomposition of the reducing agent can be achieved.

[0110] In the exhaust treatment device 100 of the above-described embodiment, one axial portion extends along the cylinder axis, and the inlet 24 is provided as an opening in the tube peripheral wall 22 of the one axial portion. The other axial portion extends in a direction inclined at a predetermined angle relative to the cylinder axis. By adjusting the direction of inclination of the other axial portion, various layouts of the exhaust treatment device 100 can be accommodated depending on the vehicle type.

[0111] In the exhaust treatment device 100 of the above-described embodiment, the guide plate 50 extends radially from the tube peripheral wall 22 to the cylindrical wall 12. One radial side of the guide plate 50 is connected to the cylindrical wall 12, and the other radial side is connected to the tube peripheral wall 22. Thus, the reducing agent flowing toward the cylindrical wall 12 can be guided toward the tube peripheral wall 22 along with the exhaust gas, and the guided reducing agent can be directed toward the inlet 24 provided in the tube peripheral wall 22 along with the exhaust gas.

[0112] (Variation)

[0113] Next, refer to Figures 11 to 16 An exhaust gas treatment device 100 according to a modified example of the present embodiment will be described. Figure 11 It is a plan view of an exhaust treatment device according to a modified example of the present embodiment. Figure 12 It is a front view of an exhaust treatment device according to a modified example of the present embodiment. Figure 13 It is a right side view of an exhaust treatment device according to a modified example of the present embodiment. Figure 14 It is a left side view of an exhaust treatment device according to a modified example of the present embodiment. Figure 15 It is a bottom view of an exhaust treatment device according to a modified example of the present embodiment. Figure 16 This is a rear view of an exhaust gas treatment device according to a modified example of the present embodiment. In the modified example, the configurations different from the above embodiment will be mainly described. Configurations identical to those in the above embodiment are denoted by the same reference numerals and their descriptions will be omitted.

[0114] In the above embodiment, the inlet 24 of the tube 20 is opened on the tube peripheral wall 22 at the one side portion PS2 in the tube axial direction. Figures 11 to 16 In the modified example shown, the inlet 24A is provided so as to open from the axially one side portion PS2 to the axially other side portion PS3 , thereby introducing the exhaust gas and reducing agent moving from the left chamber portion 10L to the right chamber portion 10R into the pipe 20 .

[0115] Furthermore, in the above-described embodiment, the inlet 16 for introducing exhaust gas from the DPF into the chamber 10 is provided on the left side wall 14L, while the inlet 16 is not provided on the right side wall 14R. In contrast, in a modified embodiment, the inlet 16 is provided on the left side wall 14L, and the inlet hole 16A is provided on the right side wall 14R. This reduces the exhaust pressure loss within the chamber 10.

[0116] In the exhaust treatment device 100 of the above embodiment, the chamber 10 , the tube 20 , and the guide plate 50 are applied as components constituting the SCR, but these components may also be applied as components constituting other exhaust treatment devices such as a DPF.

[0117] The above-described embodiments are merely examples of specific implementations of the present disclosure, and the technical scope of the present disclosure should not be limited by these embodiments. That is, the present disclosure can be implemented in various forms without departing from the gist or main features thereof.

[0118] Industrial Applicability

[0119] The present disclosure is suitable for use in a vehicle equipped with an exhaust gas treatment device that is required to effectively promote evaporation and decomposition of a reducing agent.

Claims

1. An exhaust gas treatment device for reducing nitrogen oxides contained in exhaust gas by mixing exhaust gas exhausted from an internal combustion engine with a reducing agent, the exhaust gas treatment device comprising: The chamber has a cylindrical wall extending in the axial direction of the cylinder, is open at one end in the axial direction and is provided with an inlet for introducing exhaust gas, and is closed at the other end in the axial direction of the cylinder; a tube having a tube peripheral wall extending in a tube axial direction, and being surrounded from the outside by the cylindrical wall so as to form a circumferential space between the cylindrical wall and the tube peripheral wall; the tube further having an inlet and an outlet, the inlet being partially open on one side of the tube in the tube axial direction, and the outlet being partially open on the other side of the tube in the tube axial direction and located outside the chamber; an injector for injecting the reducing agent into the peripheral space; and The guide plate guides the exhaust gas and the injected reducing agent from the peripheral space side to the inlet side.

2. The exhaust gas treatment device according to claim 1, wherein: further comprising a reducing agent evaporation plate, the reducing agent evaporation plate being located in the circumferential space and being arranged so that the injected reducing agent contacts the reducing agent evaporation plate; The guide plate guides the exhaust gas and the reducing agent evaporated by contacting the reducing agent evaporation plate from the peripheral space side to the inlet side.

3. The exhaust gas treatment device according to claim 2, wherein: The reducing agent evaporation plate is arranged along the cylindrical wall.

4. The exhaust gas treatment device according to claim 2, wherein: A gap is provided between the reducing agent evaporation plate and the cylindrical wall.

5. The exhaust gas treatment device according to claim 1, wherein: The one side portion in the tube axis direction extends along the cylinder axis direction, The inlet is opened on the peripheral wall of the tube at one side in the tube axis direction. The other side portion in the tube axis direction extends in a direction inclined at a predetermined angle with respect to the cylinder axis direction.

6. The exhaust gas treatment device according to claim 1, wherein: The guide plate extends radially from the tube peripheral wall to the cylindrical wall. One radial side of the guide plate is connected to the cylindrical wall, and the other radial side is connected to the tube peripheral wall.

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