Exhaust gas rectifier and exhaust gas purification system

Abstract

To reduce a generation risk of deposit caused by urea in a downstream side of a urea water injection device.SOLUTION: An exhaust gas flow straightening device includes an exhaust gas deflecting part located on an upstream side relative to a urea water injection device in a flow direction of exhaust gas. The exhaust gas deflecting part includes a plurality of individual areas each having an opening part through which the exhaust gas passes. The plurality of individual areas are aligned in one direction. Opening ratios of the plurality of individual areas are different in the one direction.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an exhaust gas rectifying device and an exhaust gas purification system.

Background Art

[0002] In a diesel engine, a technique for reducing nitrogen oxides in exhaust gas is disclosed in, for example, Patent Document 1. In Patent Document 1, in the middle of an exhaust pipe through which exhaust gas passes, an SCR catalyst for urea selective catalytic reduction and a urea water injection unit are provided to purify the exhaust gas. Then, by mixing the exhaust gas with urea water and passing it through the SCR catalyst, nitrogen oxides in the exhaust gas are reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the urea water injected from the urea water injection device locally collides with the inner surface of the pipe through which high-temperature exhaust gas flows, the temperature of the pipe locally decreases due to the latent heat of vaporization of the urea water. Therefore, a problem occurs in that solids (deposits) derived from the urea that could not be completely evaporated are generated. In particular, when a large amount of urea water collides with the lower surface in the gravity direction inside the pipe, a pool of urea water occurs, increasing the risk of deposits derived from the urea that could not be completely evaporated. When the deposition of deposits in the pipe progresses, it may cause deterioration of fuel consumption due to an increase in exhaust pressure loss, an increase in nitrogen oxide emissions due to a decrease in urea mixing property, damage to the downstream catalyst due to the collision of the generated deposits when they peel off, and the like. Therefore, it is necessary to reduce the risk of deposit generation.

[0005] The present invention was made to solve the above-mentioned problems, and its objective is to provide an exhaust gas straightening device and an exhaust gas purification system that can reduce the risk of urea-derived deposit formation downstream of a urea water injection device. [Means for solving the problem]

[0006] An exhaust gas straightening device according to one aspect of the present invention includes an exhaust deflection section located upstream of the direction in which the exhaust gas flows to the urea water injection device, the exhaust deflection section includes a plurality of individual regions having openings through which the exhaust gas passes, the plurality of individual regions are arranged in a single direction, and the opening ratios of the plurality of individual regions differ in that single direction.

[0007] An exhaust gas purification system according to another aspect of the present invention comprises the exhaust gas rectifier described above, a DPF system, and an SCR system including the urea water injection device. [Effects of the Invention]

[0008] This reduces the risk of urea-derived deposit formation downstream of the urea water injection system. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram showing the schematic configuration of a tractor according to one embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating the configuration of the intake and exhaust systems of the engine of the tractor described above. [Figure 3] This is a schematic perspective view showing the exhaust gas purification system located in the exhaust system described above. [Figure 4] This is a schematic perspective view showing an example of the configuration of the exhaust gas rectifier in the exhaust gas purification system described above. [Figure 5] This is an exploded perspective view of the connection part of the exhaust gas rectifier described above. [Figure 6] This is a front view of an exhaust deflection plate, which is an example of an exhaust deflection section of the exhaust gas straightening device described above. [Figure 7] It is an explanatory diagram schematically showing the flow of exhaust gas in the first exhaust gas pipe of the exhaust gas rectifying device. [Figure 8] It is an explanatory diagram schematically showing the flow of exhaust gas in the first exhaust gas pipe. [Figure 9] It is an explanatory diagram schematically showing the flow of exhaust gas in the first exhaust gas pipe. [Figure 10] It is an explanatory diagram schematically showing the distribution of urea water adhering to the inner surface of the first exhaust gas pipe. [Figure 11] It is an explanatory diagram schematically showing the distribution of urea water adhering to the inner surface of the first exhaust gas pipe. [Figure 12] It is an explanatory diagram schematically showing the flow of exhaust gas in the first exhaust gas pipe in the case where the exhaust gas deflector plate is not arranged at the connection part (comparative example). [Figure 13] It is an explanatory diagram schematically showing the flow of exhaust gas in the first exhaust gas pipe in the comparative example. [Figure 14] It is an explanatory diagram schematically showing the flow of exhaust gas in the first exhaust gas pipe in the comparative example. [Figure 15] In the comparative example, it is an explanatory diagram schematically showing the distribution of urea water adhering to the inner surface of the first exhaust gas pipe. [Figure 16] In the comparative example, it is an explanatory diagram schematically showing the distribution of urea water adhering to the inner surface of the first exhaust gas pipe. [Figure 17] It is a front view schematically showing another configuration of the exhaust gas deflector plate. [Figure 18] It is a front view schematically showing still another configuration of the exhaust gas deflector plate. [Figure 19] It is a front view schematically showing still another configuration of the exhaust gas deflector plate. [Figure 20] It is a front view schematically showing still another configuration of the exhaust gas deflector plate. [Figure 21] It is a front view schematically showing still another configuration of the exhaust gas deflector plate. [Figure 22]It is a front view schematically showing still another configuration of the exhaust deflecting plate.

Mode for Carrying Out the Invention

[0010] Embodiments of the present invention will be described based on the drawings as follows. In this embodiment, a tractor is taken as an example of the work vehicle, but the work vehicle may be a manned work vehicle other than a tractor or an unmanned work vehicle. The manned work vehicle includes, for example, various harvesters, lawn mowers, rice transplanters, combines, civil engineering and construction work machines (such as wheel loaders), snow removal vehicles, and the like. The unmanned work vehicle includes, for example, unmanned lawn mowers.

[0011] Also, in this specification, unless otherwise specified, the direction in which the tractor as the work vehicle travels during work is defined as "front", and the opposite direction is defined as "rear". Also, the right side facing the traveling direction of the tractor is defined as right, and the left side is defined as left. And the direction perpendicular to the front-rear direction and the left-right direction of the tractor is defined as the vertical direction. At this time, the downstream side in the direction of gravity is defined as down, and the opposite side (upstream side) is defined as up.

[0012] 〔1. Configuration of Work Vehicle〕 FIG. 1 is an explanatory view showing a schematic configuration of a tractor 1 according to this embodiment. The tractor 1 includes a vehicle body portion 3 to which a work implement 2 can be attached on the rear side. A pair of left and right front wheels 4 are attached to the front portion of the vehicle body portion 3. A pair of left and right rear wheels 5 are attached to the rear portion of the vehicle body portion 3. A bonnet 6 is disposed at the front portion of the vehicle body portion 3. An engine 10 (diesel engine) as a drive source is housed in the bonnet 6.

[0013] A DPF (Diesel Particulate Filter) system 11 is installed on the upper side of the engine 10. The DPF system 11 is a system that collects particulate matter (PM) contained in the exhaust gas discharged from the engine 10. A Selective Catalytic Reduction (SCR) system 12 is installed on the rear side of the engine 10. The SCR system 12 is a system that reduces nitrogen oxides (NOx) contained in the exhaust gas by adding urea water (reducing agent) stored in a urea water storage tank (reducing agent storage tank) 12T to the exhaust gas discharged from the engine 10 via the DPF system 11. Details of the DPF system 11 and the SCR system 12 will be described later.

[0014] A cabin 13 for the user to sit in is provided on the rear side of the bonnet 6. Inside the cabin 13 are a steering wheel 14 for the user to steer the vehicle, and a driver's seat 15 for the user. Also inside the cabin 13 is a display unit (not shown) for the user seated in the driver's seat 15 to view information about the tractor 1.

[0015] Figure 2 is a schematic diagram illustrating the configuration of the intake and exhaust systems of engine 10. Engine 10 is provided with an intake passage 21 for drawing in air from the outside, a combustion chamber 22 for burning fuel, and an exhaust passage 23 for discharging exhaust gas from the combustion chamber 22 to the outside. Incidentally, Figure 2 shows a four-cylinder engine 10 with four combustion chambers 22, but the number of combustion chambers 22 can be changed as appropriate.

[0016] The intake passage 21 has, in order from the upstream side in the direction of airflow, an intake valve 24 and an intake manifold 25. The intake valve 24 is configured to adjust the amount of air supplied to the combustion chamber 22. The intake manifold 25 is configured to distribute and supply intake air to each of the multiple combustion chambers 22.

[0017] The engine 10 is equipped with a common rail 26 and injectors 27 to supply fuel to the combustion chambers 22. Fuel is pumped into the common rail 26 by a fuel pump (not shown). The injectors 27 are located in each combustion chamber 22 and inject the fuel stored at high pressure in the common rail 26 into each combustion chamber 22 at predetermined timings.

[0018] The exhaust passage 23 is configured, in order from the upstream side in the direction of exhaust gas flow, to include an exhaust manifold 28, an exhaust valve 29, the aforementioned DPF system 11, and an SCR system 12. The exhaust manifold 28 is configured to discharge the exhaust gas generated in each combustion chamber 22 together. The exhaust valve 29 is configured to adjust the amount of exhaust gas discharged to the outside of the engine 10.

[0019] The engine 10 is further equipped with an EGR (Exhaust Gas Recirculation) device 30. The EGR device 30 is an exhaust gas recirculation device that recirculates a portion of the exhaust gas from the exhaust manifold 28 to the intake side. Specifically, the EGR device 30 includes an EGR passage 31 that recirculates a portion of the exhaust gas from the exhaust passage 23 to the intake passage 21. In the EGR passage 31, an EGR cooler 32 and an EGR valve 33 are arranged in order from the upstream side in the direction of exhaust gas flow. The EGR cooler 32 cools the recirculating exhaust gas. The EGR valve 33 is a valve for adjusting the recirculation flow rate of the exhaust gas.

[0020] The EGR device 30 recirculates a portion of the exhaust gas to the intake side, thereby reducing the amount of oxygen in the intake gas. This lowers the combustion temperature, thus reducing the generation of nitrogen oxides called NOx.

[0021] The DPF system 11 comprises, in order from the upstream side in the direction of exhaust gas flow, an oxidation catalyst 11a and a soot filter 11b. The oxidation catalyst 11a and the soot filter 11b are housed in the DPF case 11P.

[0022] The oxidation catalyst 11a is configured to promote the oxidation of carbon monoxide, nitric oxide, and other particles contained in the exhaust gas. The soot filter 11b is configured to capture PM such as soot contained in the exhaust gas. The PM captured and deposited by the soot filter 11b is removed by combustion by performing DPF regeneration control at an appropriate timing.

[0023] The SCR system 12 comprises, in order from the upstream side in the direction of exhaust gas flow, a urea water injection device 12a, a selective reduction catalyst (SCR) 12b, and an ammonia slip suppression catalyst (ASC) 12c. The selective reduction catalyst 12b and the ammonia slip suppression catalyst 12c are housed in a hollow SCR case 12P.

[0024] The urea water injection device 12a is a module (DM: Dosing Module) that consists of, for example, a urea water injection nozzle and injects urea water supplied from the urea water supply device 12S (described later) to add to the exhaust gas supplied from the DPF system 11. The selective reduction catalyst 12b is configured to selectively reduce NOx contained in the exhaust gas in an atmosphere where ammonia (NH3) taken into the exhaust gas from the urea water is present.

[0025] The ammonia slip suppression catalyst 12c consists of an oxidation catalyst such as platinum and is configured to oxidize ammonia that has unexpectedly passed through the selective reduction catalyst 12b. By oxidizing ammonia and converting it into nitrogen, nitric oxide, water, etc., the release of ammonia into the outside is prevented.

[0026] The SCR system 12 further comprises a urea water storage tank 12T and a urea water supply device 12S. The urea water storage tank 12T is a tank for storing the urea water used as a reducing agent. The urea water supply device 12S is configured to include a pump and the like. The urea water supply device 12S draws urea water from the urea water storage tank 12T via the urea water outlet passage 12d and supplies urea water to the urea water injection device 12a via the urea water supply passage 12f. A portion of the urea water drawn in by the urea water supply device 12S is returned to the urea water storage tank 12T via the urea water return passage 12e.

[0027] Tractor 1 is further equipped with various sensors. These sensors include, for example, an engine speed sensor 41, an oxidation catalyst temperature sensor 42, a soot filter temperature sensor 43, and a differential pressure sensor 44. The engine speed sensor 41 detects the rotational speed of the engine 10. The oxidation catalyst temperature sensor 42 detects the temperature upstream of the oxidation catalyst 11a in the DPF system 11. The soot filter temperature sensor 43 detects the temperature upstream of the soot filter 11b in the DPF system 11. The differential pressure sensor 44 detects the differential pressure between the upstream and downstream sides of the soot filter 11b in the DPF system 11.

[0028] The sensors also include, for example, an upstream NOx sensor 45, a downstream NOx sensor 46, a urea solution level sensor 47, and a urea solution supply pressure sensor (not shown). The upstream NOx sensor 45 detects the concentration of NOx contained in the exhaust gas upstream of the selective reduction catalyst 12b of the SCR system 12 (more precisely, upstream of the urea solution injection device 12a) and downstream of the soot filter 11b in the DPF system 11. The downstream NOx sensor 46 detects the concentration of NOx contained in the exhaust gas downstream of the ammonia slip suppression catalyst 12c of the SCR system 12. The urea solution level sensor 47 detects the remaining amount of urea solution stored in the urea solution storage tank 12T of the SCR system 12. The urea solution supply pressure sensor detects the supply pressure of urea solution to the urea solution injection device 12a of the SCR system 12.

[0029] The tractor 1 further comprises a control unit 50. The control unit 50 includes an ECU (Engine Control Unit) 51 and a DCU (Dosing Control Unit) 52. The ECU 51 mainly controls the output state of the engine 10 and the DPF system 11, etc. The DCU 52 controls the SCR system 12.

[0030] The control unit 50 uses the detection information from the various sensors described above, as well as a preset map, to control the amount of air supplied by the intake valve 24, the amount of exhaust by the exhaust valve 29, the fuel injection timing and amount by the injector 27, the return flow rate by the EGR valve 33, etc., so that the output state of the engine 10 reaches a predetermined output state. For example, the control unit 50 controls the amount of air supplied, the amount of exhaust, the fuel injection timing and amount by the injector 27, the return flow rate, etc., so that the engine speed detected by the engine speed sensor 41 reaches a predetermined engine speed.

[0031] Furthermore, the control unit 50 uses detection information from various sensors to control the amount of urea solution injected from the urea solution injection device 12a so that the NOx removal rate reaches a predetermined rate. For example, the control unit 50 estimates the amount of ammonia required to reduce NOx by the selective reduction catalyst 12b based on the NOx concentration upstream of the selective reduction catalyst 12b detected by the upstream NOx sensor 45, and controls the amount of urea solution injected from the urea solution injection device 12a. In addition, the control unit 50 estimates the proportion of NOx reduced by the selective reduction catalyst 12b based on the NOx concentration downstream of the selective reduction catalyst 12b detected by the downstream NOx sensor 46, and performs feedback correction on the amount of urea solution injected, which is determined from the detection value of the upstream NOx sensor 45, so that the NOx removal rate reaches a predetermined rate.

[0032] [2. Regarding the exhaust gas purification system] The tractor 1, which serves as a work vehicle in this embodiment, is equipped with an exhaust gas purification system 60. Figure 3 is a schematic perspective view of the exhaust gas purification system 60 in this embodiment. In Figure 3, for convenience, the three directions perpendicular to each other are referred to as the X, Y, and Z directions. Each of the X, Y, and Z directions indicates the direction in which the exhaust gas flows, but they do not necessarily coincide with the front / back, left / right, or up / down directions.

[0033] The exhaust gas purification system 60 is a system that purifies the exhaust gas emitted from the engine 10. The exhaust gas purification system 60 is comprised of the DPF system 11 and the SCR system 12 including the urea water injection device 12a, as well as an exhaust gas rectifier 70.

[0034] The exhaust gas rectifier 70 is located downstream of the DPF system 11 in the direction of exhaust gas flow. That is, the DPF system 11 is located upstream of the exhaust gas rectifier 70. The exhaust inlet 11E of the DPF case 11P of the DPF system 11 is connected to the exhaust passage 23 (see Figure 2) through which the exhaust gas discharged from the engine 10 passes.

[0035] Furthermore, the exhaust gas rectifier 70 is located upstream of the SCR case 12P of the SCR system 12 in the direction of exhaust gas flow. The exhaust inlet of the SCR case 12P is connected to the exhaust outlet 71E of the first exhaust gas piping 71 of the exhaust gas rectifier 70, which will be described later. The details of the exhaust gas rectifier 70 will be described below.

[0036] Figure 4 is a schematic perspective view showing an example configuration of the exhaust gas rectifier 70 shown in Figures 2 and 3. The exhaust gas rectifier 70 comprises a first exhaust gas pipe 71, a second exhaust gas pipe 72, and an exhaust deflection section 73. The urea water injection device 12a described above is attached to the first exhaust gas pipe 71. Note that the shapes of the first exhaust gas pipe 71 and the second exhaust gas pipe 72 shown below are merely examples and are not limited to the following examples.

[0037] The first exhaust gas piping 71 comprises a first flow channel pipe 711 and a second flow channel pipe 712. The first flow channel pipe 711 extends in the X direction. The downstream end of the first flow channel pipe 711 in the X direction is connected to the SCR case 12P (see Figure 2) of the SCR system 12. The second flow channel pipe 712 extends in the Y direction and is connected to the outer surface of the first flow channel pipe 711 by welding or the like. The connection between the first flow channel pipe 711 and the second flow channel pipe 712 constitutes a first bend 71B (see Figure 3), which will be described later, that bends the direction of travel of the exhaust gas. The interiors of the first flow channel pipe 711 and the second flow channel pipe 712 constitute a connecting passage through which the exhaust gas flows.

[0038] The urea water injection device 12a is attached to the upstream end face in the X direction of the first flow channel pipe 711 and injects urea water into the exhaust gas flowing from the second flow channel pipe 712 into the first flow channel pipe 711. The urea water injection device 12a is attached to the end face of the first flow channel pipe 711 so that the urea water is injected at a predetermined angle.

[0039] The second exhaust gas pipe 72 is located upstream of the first exhaust gas pipe 71 in the direction of exhaust gas flow (Y direction in Figure 4). More specifically, the second exhaust gas pipe 72 is located upstream in the Y direction of the second flow channel pipe 712 of the first exhaust gas pipe 71. The second exhaust gas pipe 72 is formed by bending from the Z direction to the Y direction. The bend in the second exhaust gas pipe 72 constitutes the second bend 72B (see Figure 3), which will be described later. The upstream end of the second exhaust gas pipe 72 in the Z direction is connected to the DPF case 11P (see Figures 2 and 3) of the DPF system 11.

[0040] The exhaust deflection section 73 is located upstream in the Y direction from the second flow path pipe 712 of the first exhaust gas piping 71. That is, the exhaust deflection section 73 is located upstream in the direction in which the exhaust gas flows toward the urea water injection device 12a. The exhaust deflection section 73 is also located downstream in the Y direction from the second exhaust gas piping 72. In this embodiment, the exhaust deflection section 73 includes a plate-shaped exhaust deflection plate 80. The exhaust deflection plate 80 has an opening through which the exhaust gas passes, but the details of the exhaust deflection plate 80 will be described later. The exhaust deflection plate 80 is located at the connection section 74 that connects the first exhaust gas piping 71 and the second exhaust gas piping 72. More details are as follows.

[0041] Figure 5 is an exploded perspective view of the connection portion 74. The connection portion 74 includes a first flange portion 71F of the first exhaust gas piping 71 and a second flange portion 72F of the second exhaust gas piping 72. The first flange portion 71F is located at the upstream end in the Y direction of the second flow channel pipe 712 of the first exhaust gas piping 71. The second flange portion 72F is located at the downstream end in the Y direction of the second exhaust gas piping 72. The first flange portion 71F and the second flange portion 72F are fastened together by fastening members such as bolts Bo (see Figure 4) and nuts (not shown). With the exhaust deflection plate 80 positioned between the first flange portion 71F and the second flange portion 72F, the exhaust deflection plate 80 is attached between the first flange portion 71F and the second flange portion 72F by fastening the first flange portion 71F and the second flange portion 72F with the fastening members.

[0042] The first flange portion 71F has a first passage portion 71P, which is an opening through which exhaust gas passes. The inner diameter of the first passage portion 71P is the same as the inner diameter of the first exhaust gas piping 71 (particularly the second flow path pipe 712). The first flange portion 71F also has first holes 71a at its four corners. Bolts Bo, which serve as fastening members, are inserted through each of the first holes 71a.

[0043] The second flange portion 72F has a second passage portion 72P, which is an opening through which exhaust gas passes. The inner diameter of the second passage portion 72P is the same as the inner diameter of the second exhaust gas pipe 72. The second flange portion 72F also has second holes 72a at its four corners. Bolts Bo, which serve as fastening members, are inserted through each of the second holes 72a.

[0044] The exhaust deflection plate 80 has third holes 80a at its four corners. Bolts Bo, which serve as fastening members, are inserted through each third hole 80a. By inserting each bolt Bo into the corresponding first hole 71a, third hole 80a, and second hole 72a, and then inserting the tip of each bolt Bo into a nut and tightening it, the first exhaust gas pipe 71 and the second exhaust gas pipe 72 are connected via the exhaust deflection plate 80. By releasing the tightening of the bolts Bo and nuts, the first exhaust gas pipe 71, the second exhaust gas pipe 72, and the exhaust deflection plate 80 can be disassembled. In other words, the connection part 74 can be disassembled.

[0045] In the exhaust gas straightening device 70 configuration described above, the exhaust gas discharged from the DPF system 11 and flowing through the second exhaust gas pipe 72 changes direction from the Z direction to the Y direction by the second exhaust gas pipe 72 and flows into the first exhaust gas pipe 71 through the opening of the exhaust deflection section 73. Inside the first exhaust gas pipe 71, urea solution is injected from the urea solution injection device 12a shown in Figure 4 and added to the exhaust gas. After the urea solution is added, the exhaust gas travels in the X direction inside the first exhaust gas pipe 71 and is introduced into the SCR system 12 (see Figure 2).

[0046] From the viewpoint of facilitating the installation and removal of the exhaust deflection plate 80, it is desirable that the exhaust deflection plate 80 be located at the connection portion 74 that connects the first exhaust gas pipe 71 and the second exhaust gas pipe 72. In particular, the configuration in which the exhaust deflection plate 80 is located at the connection portion 74 is desirable because it facilitates replacement with a desired exhaust deflection plate 80 according to the shape (e.g., the way it bends) and size (e.g., the inner diameter) of the first exhaust gas pipe 71 and the second exhaust gas pipe 72.

[0047] Furthermore, in order to ensure a seal between the first flange portion 71F and the second flange portion 72F, and to facilitate the replacement of the exhaust deflection plate 80, it is desirable that the exhaust deflection plate 80 be installed between the first flange portion 71F and the second flange portion 72F.

[0048] As shown in Figure 3, the first exhaust gas pipe 71 has a first bend 71B. The second exhaust gas pipe 72 has a second bend 72B. The first bend 71B and the second bend 72B each bend the flow path through which the exhaust gas flows. In this embodiment, the first bend 71B has a shape that bends from the Y direction to the X direction, bending the flow path through which the exhaust gas flows from the Y direction to the X direction. The urea water injection device 12a described above is attached to the first bend 71B. The second bend 72B has a shape that bends from the Z direction to the Y direction, bending the flow path through which the exhaust gas flows from the Z direction to the Y direction.

[0049] From the standpoint of effectively utilizing the space between the first bent portion 71B and the second bent portion 72B, it is desirable that the exhaust deflection portion 73 (exhaust deflection plate 80) be positioned between the first bent portion 71B and the second bent portion 72B.

[0050] In particular, downstream of the first bend 71B, in order to facilitate the function and action of the exhaust deflection section 73 which generates a swirling flow described later, it is desirable that the exhaust deflection section 73 be positioned closer to the first bend 71B than to the midpoint between the first bend 71B (especially the exhaust inlet) and the second bend 72B (especially the exhaust outlet). In other words, it is desirable that the exhaust deflection section 73 be positioned between the first bend 71B and the second bend 72B, such that the distance to the first bend 71B is shorter than the distance to the second bend 72B.

[0051] [3. Details of the exhaust deflection plate] Figure 6 is a front view of the exhaust deflection plate 80 shown in Figures 4 and 5, viewed from the Y direction. For the purpose of explaining the exhaust deflection plate 80, directions are defined as follows: The Z direction shown in Figures 4 and 5 is defined as the up-down direction, and the X direction is defined as the left-right direction. The downstream side in the Z direction is defined as the upstream side in the direction of gravity, i.e., the upper side, and the upstream side in the Z direction is defined as the downstream side in the direction of gravity, i.e., the lower side. The upstream side in the X direction is defined as the right side, and the downstream side in the X direction is defined as the left side. In each drawing, the symbols "U" indicate the top, "D" indicates the bottom, "R" indicates the right, and "L" indicates the left.

[0052] Furthermore, in Figure 6 and other figures, the outer shape of the region of the exhaust deflection plate 80 that connects to the first exhaust gas pipe 71 (particularly the first passage portion 71P of the first flange portion 71F) and the second exhaust gas pipe 72 (particularly the second passage portion 72P of the second flange portion 72F) is shown as the outer perimeter of the passage 80E. The inner diameter of the outer perimeter of the passage 80E is assumed to be equal to the inner diameter of the first exhaust gas pipe 71 (particularly the first passage portion 71P) and the second exhaust gas pipe 72 (particularly the second passage portion 72P).

[0053] The exhaust deflection plate 80 has a protrusion 80b. The protrusion 80b is located on the upper part of the outer circumference of the exhaust deflection plate 80. In this embodiment, as shown in Figure 4, the second exhaust gas pipe 72 is shaped to supply exhaust gas flowing from bottom to top to the first exhaust gas pipe 71, so the exhaust deflection plate 80 is positioned so that the protrusion 80b protrudes upward. For example, if the second exhaust gas pipe 72 is shaped to supply exhaust gas flowing from top to bottom to the first exhaust gas pipe 71, the exhaust deflection plate 80 may be positioned so that the protrusion 80b protrudes downward (rotated 180° around the Y-axis from the position in Figure 4).

[0054] The exhaust deflection plate 80, which serves as the exhaust deflection section 73, includes a plurality of individual regions 81. The plurality of individual regions 81 include a first individual region 81A and a second individual region 81B. The first individual region 81A and the second individual region 81B are located side by side in the Z direction (here, the vertical direction). That is, the plurality of individual regions 81 are located side by side in one direction. Specifically, the first individual region 81A is located above the second individual region 81B.

[0055] Multiple individual regions 81 each have an opening 81P. The opening 81P is an opening through which exhaust gas passes. The number of openings 81P in each individual region 81 is not particularly limited; there may be one or multiple. In the example in Figure 6, the first individual region 81A has multiple openings 81P. The multiple openings 81P in the first individual region 81A are all elongated holes in the left-right direction and are all the same shape. On the other hand, in the example in Figure 6, the second individual region 81B has only one opening 81P. The opening 81P in the second individual region 81B has a plano-convex shape, with a flat top and a convex bottom. The opening 81P in the second individual region 81B has the largest opening area among all the openings 81P. Hereinafter, the opening 81P with the largest opening area may be specifically referred to as opening 81Pmax.

[0056] At least one of the multiple individual regions 81 has a surrounding region 81Q. The surrounding region 81Q is the region located inside the outer perimeter of the passage 80E and around the opening 81P in each individual region 81. In Figure 6, the surrounding region 81Q is shown with hatching for the purpose of clarifying it (the same applies to the following drawings). Depending on the shape of the individual region 81 (shape and number of openings 81P), there may be individual regions 81 that do not have a surrounding region 81Q. For example, the second individual region 81B can be an individual region 81 without a surrounding region 81Q by forming the entire area with an opening 81Pmax.

[0057] In this embodiment, the aperture ratios of the multiple individual regions 81 differ in the above-mentioned direction. Here, the above-mentioned aperture ratio is defined as follows: That is, the total area of ​​one individual region 81 is A(cm²). 2) and the sum of the opening areas of at least one opening 81P in the individual region 81 is B(cm 2 When this is the case, the aperture ratio AR(%) of the individual region 81 is expressed by the following formula. AR = (B / A) × 100 Furthermore, the area of ​​the surrounding region 81Q in one individual region 81 is C(cm²). 2 ) When that is the case, A = B + C Therefore, for example, in an individual region 81 that does not have a surrounding region 81Q, C=0, and thus A=B.

[0058] When the aperture ratio of the first individual region 81A is AR1 (%) and the aperture ratio of the second individual region 81B is AR2 (%), in this embodiment, AR1 <AR2 That is the case.

[0059] Figures 7 to 9 schematically show the flow of exhaust gas in the first exhaust gas piping 71. As in this embodiment, when the exhaust deflection plate 80, which serves as the exhaust deflection section 73, is positioned at the connection section 74 between the first exhaust gas piping 71 and the second exhaust gas piping 72 such that the first individual region 81A, which has a relatively small opening ratio, is on the upper side (upstream side in the direction of gravity), and the second individual region 81B, which has a relatively large opening ratio, is on the lower side (downstream side in the direction of gravity), as shown in Figure 7, the exhaust gas passing through the exhaust deflection plate 80 flows more on the lower side than on the upper side. As a result, as shown in Figures 8 and 9, when the exhaust gas is supplied to the downstream side of the urea water injection device 12a (first flow path pipe 711) and urea water is injected from the urea water injection device 12a into the exhaust gas, a swirling flow (swirling flow) that moves from bottom to top can be easily generated downstream of the urea water injection device 12a.

[0060] Due to the generation of the swirling flow described above, the urea solution injected from the urea solution injection device 12a adheres to the upper part of the inner surface of the first exhaust gas pipe 71 (particularly the first flow path pipe 711), against the downward force of gravity. Furthermore, the injected urea solution flows in the X direction within the first exhaust gas pipe 71 due to the swirling flow described above. It is widely diffused in the X direction and adheres to a wide area. Figures 10 and 11 show that The distribution of urea solution AS adhering to the inner surface of the first exhaust gas piping 71 (particularly the first flow channel pipe 711) is schematically shown. As a result, localized adhesion of urea solution within the first exhaust gas piping 71 is reduced, thereby reducing the risk of urea-derived solid matter (deposits) forming within the first exhaust gas piping 71.

[0061] Figures 12 to 14 schematically show the flow of exhaust gas in the first exhaust gas pipe 71 when the exhaust deflection plate 80 of this embodiment is not placed at the connection point 74 between the first exhaust gas pipe 71 and the second exhaust gas pipe 72 (comparative example). As shown in Figure 12, the exhaust gas supplied from the second exhaust gas pipe 72 flows almost equally in the upper and lower parts inside the first exhaust gas pipe 71 (second flow channel pipe 712). Therefore, as shown in Figures 13 and 14, when the exhaust gas is supplied to the downstream side of the urea water injection device 12a (first flow channel pipe 711) and urea water is injected from the urea water injection device 12a into the exhaust gas, the injected urea water adheres to the lower part of the inner surface of the first exhaust gas pipe 71 (especially the first flow channel pipe 711) and close to the urea water injection device 12a, due to downward gravity. Figures 15 and 16 schematically show the distribution of urea solution AS adhering to the inner surface of the first exhaust gas pipe 71 (particularly the first flow channel pipe 711) in the comparative example. In the comparative example, localized adhesion of urea solution to the lower part of the inner surface of the first exhaust gas pipe 71 makes it easier for urea solution to accumulate, increasing the risk of deposit formation.

[0062] To reliably reduce the risk of deposit formation, as shown in Figure 6, it is desirable to make the opening ratio AR2 of the second individual region 81B larger than the opening ratio AR1 of the first individual region 81A, thereby facilitating the generation of a swirling flow of exhaust gas within the first exhaust gas piping 71. In other words, when the direction in which the multiple individual regions 81 are aligned is considered the direction of gravity, it is desirable that the opening ratio AR of the multiple individual regions 81 increases from the upper side (upstream side in the direction of gravity) to the lower side (downstream side in the direction of gravity). To put it another way, it is desirable that the opening ratio AR of the multiple individual regions 81 increases from one side to the other side in one direction.

[0063] Figure 17 is a schematic front view showing another configuration of the exhaust deflection plate 80 as the exhaust deflection section 73. As shown in the figure, the opening 81P of the individual region 81 (second individual region 81B) with the largest opening ratio AR among the multiple individual regions 81 may be located across the central part CP in the direction of gravity. However, in the configuration of Figure 17, the amount of exhaust gas passing near the central part CP of the exhaust deflection plate 80 increases. As a result, there is a concern that the exhaust gas passing near the central part CP of the exhaust deflection plate 80 will strongly collide with the urea water injected from the urea water injection device 12a at a predetermined angle, thereby disrupting the trajectory of the urea water.

[0064] To reduce such turbulence in the urea solution trajectory, it is desirable to restrict the passage of exhaust gas to some extent at the central CP of the exhaust deflection plate 80. To achieve this, it is desirable not to position the opening 81P of the second individual region 81B, which has the largest aperture ratio AR, near the central CP of the exhaust deflection plate 80. From this viewpoint, as shown in Figure 6, it is desirable that the opening 81P of the individual region 81 with the largest aperture ratio AR (second individual region 81B) among the multiple individual regions 81 be located below the central CP in the direction of gravity in the exhaust deflection section 73, that is, on the other side of the central CP in one direction of the exhaust deflection section 73.

[0065] In particular, in order to suppress the passage of exhaust gas to some extent at the central part CP of the exhaust deflection plate 80, and to reliably generate a swirling flow that rotates from bottom to top downstream of the urea water injection device 12a in the first exhaust gas piping 71, as shown in Figures 7 and 8, it is desirable that the second individual region 81B be located below the first individual region 81A, as shown in Figure 6. In other words, among the multiple individual regions 81, it is desirable that the individual region 81 with the largest opening ratio AR (the second individual region 81B) be located below the other individual regions 81 (the first individual region 81A) (on the other side in one direction).

[0066] Figure 18 is a schematic front view showing yet another configuration of the exhaust deflection plate 80 as the exhaust deflection section 73. As shown in the figure, the opening 81P of the first individual region 81A may be circular (perfect circle). Although not shown, the opening 81P of the first individual region 81A may also be square.

[0067] However, in the first individual region 81A, from the viewpoint of making it easier to increase the aperture ratio AR by reducing the area of ​​the surrounding region 81Q, it is desirable that the opening 81P of the first individual region 81A be an elongated hole in the left-right direction, as shown in Figures 6 and 17. Although not shown, the opening 81P of the first individual region 81A may also be an elongated hole in the up-down direction, or an elongated hole in an oblique direction intersecting the up-down and left-right directions. In other words, among the multiple individual regions 81, it is desirable that the openings 81P of the other individual regions 81 (the first individual region 81A), excluding the second individual region 81B which has the largest aperture ratio AR, have a longitudinal direction.

[0068] Furthermore, if the opening ratio of other individual regions 81 (first individual region 81A) is low, the flow of exhaust gas above the exhaust deflection plate 80 is restricted, and a large amount of exhaust gas passes below the exhaust deflection plate 80. As a result, there is a concern that the swirling speed of the swirling flow generated inside the first exhaust gas piping 71 will become too fast, causing urea solution to locally contact and adhere to the inner surface of the first exhaust gas piping 71, increasing the risk of deposit formation. In order to keep the swirling speed of the swirling flow within an appropriate range, it is desirable to relax the restrictions on the passage of exhaust gas passing through other individual regions 81 (first individual region 81A). The above configuration in which the opening 81P of the first individual region 81A has a longitudinal direction is desirable because it can increase the opening ratio AR1 of the first individual region 81A (compared to a configuration in which the opening 81P is a perfect circle, etc.), thus allowing for relaxation of the restrictions on the passage of exhaust gas and keeping the swirling speed of the swirling flow within an appropriate range.

[0069] In particular, from the viewpoint of improving the productivity of the exhaust deflection plate 80 as an exhaust deflection section 73 by forming multiple openings 81P by punching using the same die, it is desirable that the other individual regions 81 (first individual region 81A) have multiple openings 81P of the same shape, as shown in Figures 6 and 17.

[0070] The shape of the longitudinal opening 81P is not limited to the elongated shape with an arc portion as shown in Figures 6 and 17. Figure 19 is a schematic front view showing yet another configuration of the exhaust deflection plate 80 as the exhaust deflection section 73. As shown in the figure, the longitudinal opening 81P may be a rectangular shape that is long in the left-right direction. Although not shown, the longitudinal opening 81P may also be a rectangular shape that is long in the up-down direction or diagonally.

[0071] In order to homogeneously mix the urea solution injected from the urea solution injection device 12a shown in Figure 4 with the exhaust gas that has passed through the exhaust deflection plate 80, it is desirable to evenly distribute the exhaust gas that has passed through the opening 81P to the urea solution injected from the urea solution injection device 12a, specifically the urea solution on the side closer to the urea solution injection device 12a (upstream side in the X direction) and the urea solution on the side further away from the urea solution injection device 12a (downstream side in the X direction). To achieve this, it is desirable that the exhaust deflection plate 80, which serves as the exhaust deflection section 73, has a symmetrical shape in the left-right direction, as shown in Figures 6, 17, and 18. In other words, it is desirable that the exhaust deflection section 73 has a symmetrical shape in one direction, which is the direction of gravity, and in another direction perpendicular to it.

[0072] Figure 20 is a schematic front view showing yet another configuration of the exhaust deflection plate 80 as the exhaust deflection section 73. In order to reduce the disturbance of the trajectory of the urea water immediately after it is injected from the urea water injection device 12a shown in Figure 4 and to generate a clean swirling flow, it is desirable to direct a smaller amount of exhaust gas that has passed through the opening 81P of the exhaust deflection plate 80 towards the urea water on the side closer to the urea water injection device 12a (upstream side in the X direction) than towards the urea water on the side further away from the urea water injection device 12a (downstream side in the X direction). For this purpose, it is desirable that the exhaust deflection plate 80 as the exhaust deflection section 73 has an asymmetric shape in the left-right direction, as shown in Figure 20. In other words, it is desirable that the exhaust deflection section 73 has an asymmetric shape in one direction, which is the direction of gravity, and in the other direction perpendicular to it.

[0073] In the configuration example shown in Figure 20, the second individual region 81B is configured to have an opening 81Pmax with the largest opening area and an opening 81P1 with a smaller opening area. The opening 81P1 is located to the upper left of the opening 81Pmax via the surrounding region 81Q. In this configuration, the opening ratio of the exhaust deflection plate 80 becomes smaller on the left side and larger on the right side.

[0074] Therefore, when viewed from the upstream side in the Y direction in Figure 4, the exhaust deflection plate 80 should be positioned between the first exhaust gas pipe 71 and the second exhaust gas pipe 72 such that the left side of the exhaust deflection plate 80 (the side with a smaller opening ratio) is closer to the urea water injection device 12a, and the right side of the exhaust deflection plate 80 (the side with a larger opening ratio) is further away from the urea water injection device 12a. With this arrangement, less exhaust gas passing through the opening 81P of the exhaust deflection plate 80 can be directed to the urea water on the side closer to the urea water injection device 12a than to the urea water on the side further away from the urea water injection device 12a.

[0075] [4. Variations] Figure 21 is a schematic front view showing yet another configuration of the exhaust deflection plate 80. As shown in the figure, the multiple individual regions 81 may further include a third individual region 81C in addition to the first individual region 81A and the second individual region 81B. The first individual region 81A, the second individual region 81B, and the third individual region 81C are arranged in this order from top to bottom. In this case, if the opening ratio of the third individual region 81C is AR3 (%), AR1 <AR2<AR3 This is the case. Furthermore, the third individual region 81C, which has the largest aperture ratio, is assumed to be located below the central part CP in the vertical direction.

[0076] Even with this configuration of the exhaust deflection plate 80, a swirling flow that rotates from bottom to top can be easily generated downstream of the urea water injection device 12a (see Figure 4, etc.), thereby achieving the effects of this embodiment described above. The exhaust deflection plate 80 may also include four or more individual regions 81, and the opening ratio of each individual region 81 may increase from top to bottom.

[0077] Figure 22 is a schematic front view showing yet another configuration of the exhaust deflection plate 80. As shown in the figure, the configuration includes a plurality of individual regions 81, a first individual region 81A, a second individual region 81B, and a third individual region 81C, which are arranged in this order from top to bottom. AR3 <AR1<AR2 This is also possible. In other words, among the multiple individual regions 81, the individual region 81 with the largest aperture ratio (the second individual region 81B in the example of Figure 22) may be located below the other individual region 81 with a relatively smaller aperture ratio (the third individual region 81C in the example of Figure 22). Note that the second individual region 81B, which has the largest aperture ratio, is located below the central part CP in the vertical direction.

[0078] In this configuration, the amount of exhaust gas flowing below the first exhaust gas pipe 71 (second flow path pipe 712) is reduced compared to the configuration in Figure 6. However, it remains possible to generate a swirling flow that rotates from bottom to top downstream of the urea water injection device 12a (see Figure 4, etc.), and therefore, the effects of this embodiment described above can be obtained.

[0079] In addition to being composed of a plate-shaped exhaust deflection plate 80 sandwiched between the first flange portion 71F and the second flange portion 72F, the exhaust deflection section 73 may also be a welded component directly attached by welding to the inside of the first exhaust gas piping 71 or the second exhaust gas piping 72 upstream of the urea water injection device 12a.

[0080] [5. Supplement] In this embodiment, as shown in Figure 3, a configuration in which the exhaust gas rectifier 70 is located downstream of the DPF system 11 has been described, but the configuration is not limited to this. For example, in the exhaust gas purification system 60, the exhaust gas rectifier 70, SCR system 12, DPF system 11, and SCR system 12 may be arranged in this order from the upstream side in the direction in which the exhaust gas flows.

[0081] [6. Addendum] The exhaust gas rectifier and exhaust gas purification system described in this embodiment can be expressed as follows (1) to (15).

[0082] The exhaust gas rectifier in Appendix (1) is The urea water injection device is equipped with an exhaust deflection unit located upstream of the direction in which the exhaust gas flows. The exhaust deflection section includes a plurality of individual regions having openings through which the exhaust gas passes, The aforementioned multiple individual regions are arranged in a line in one direction, The aperture ratios of the aforementioned multiple individual regions differ in one direction.

[0083] The exhaust gas rectifier described in Appendix (2) is the exhaust gas rectifier described in Appendix (1), The aperture ratio of the plurality of individual regions increases as you move from one side to the other in one direction.

[0084] The exhaust gas rectifier described in Appendix (3) is the exhaust gas rectifier described in Appendix (2), Of the plurality of individual regions, the opening in the individual region with the largest opening ratio is located on the other side of the central part in one direction of the exhaust deflection portion.

[0085] The exhaust gas rectifier described in Appendix (4) is the exhaust gas rectifier described in Appendix (3), Of the aforementioned multiple individual regions, the individual region with the largest aperture ratio is located on the other side of the other individual regions.

[0086] The exhaust gas rectifier described in Appendix (5) is the exhaust gas rectifier described in Appendix (4), The openings in the other individual regions have a longitudinal direction.

[0087] The exhaust gas rectifier described in Appendix (6) is the exhaust gas rectifier described in Appendix (5), Each of the other individual regions has multiple openings of the same shape.

[0088] The exhaust gas rectifier in Appendix (7) is an exhaust gas rectifier described in any of Appendix (1) to (6), The exhaust deflection section has a shape that is symmetrical in a direction perpendicular to the aforementioned one direction.

[0089] The exhaust gas rectifier in Appendix (8) is an exhaust gas rectifier described in any of Appendix (1) to (6), The exhaust deflection section has an asymmetrical shape in a direction perpendicular to the aforementioned one direction.

[0090] The exhaust gas rectifier in Appendix (9) is an exhaust gas rectifier described in any of Appendix (1) to (8), The first exhaust gas piping to which the urea water injection device is attached, The system further comprises a second exhaust gas pipe located upstream of the first exhaust gas pipe, The exhaust deflection section includes an exhaust deflection plate. The exhaust deflection plate is located at the connection point that connects the first exhaust gas pipe and the second exhaust gas pipe.

[0091] The exhaust gas rectifier described in Appendix (10) is the exhaust gas rectifier described in Appendix (9), The aforementioned connection part is The first flange portion of the first exhaust gas piping, The second exhaust gas piping includes a second flange portion, The exhaust deflection plate is installed between the first flange portion and the second flange portion.

[0092] The exhaust gas rectifier in Appendix (11) is an exhaust gas rectifier described in any of Appendix (1) to (8), The first exhaust gas piping to which the urea water injection device is attached, The system further comprises a second exhaust gas pipe located upstream of the first exhaust gas pipe, The first exhaust gas piping has a first bend, The second exhaust gas pipe has a second bend, The exhaust deflection section is positioned between the first bending section and the second bending section.

[0093] The exhaust gas rectifier described in Appendix (12) is the exhaust gas rectifier described in Appendix (11), The urea water spray device is attached to the first bend, The exhaust deflection portion is positioned closer to the first bend than to the center between the first and second bends.

[0094] The exhaust gas rectifier described in Appendix (13) is an exhaust gas rectifier described in any of Appendix (1) to (12), The aforementioned one direction is the direction of gravity.

[0095] The exhaust gas purification system described in Appendix (14) is An exhaust gas rectifier described in any of the appendices (1) to (13), DPF system and, The system comprises an SCR system including the urea water injection device.

[0096] The exhaust gas purification system in Appendix (15) is the same as the exhaust gas purification system described in Appendix (14), The DPF system is located upstream of the exhaust gas rectifier.

[0097] Although embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and it can be expanded or modified without departing from the spirit of the invention. [Industrial applicability]

[0098] This invention can be used, for example, in work vehicles such as tractors. [Explanation of Symbols]

[0099] 12a Urea water injection device 60 Exhaust gas purification system 70 Exhaust gas rectifier 71. First exhaust gas piping 71B First bending section 71F First flange section 72. Second exhaust gas piping 72B Second bending section 72F Second flange section 73 Exhaust deflector 74 Connection part 80 Exhaust deflector plate (exhaust deflector section) 81 specific areas 81A First Specific Area (Specific Area) 81B Section 2 (Specific Area) 81C Third Individual Domain (Individual Domain) 81P opening 81Pmax opening 81Q Weekly Domain

Claims

1. The urea water injection device is equipped with an exhaust deflection unit located upstream of the direction in which the exhaust gas flows. The exhaust deflection section includes a plurality of individual regions having openings through which the exhaust gas passes, The aforementioned multiple individual regions are arranged in a line in one direction, The aperture ratios of the aforementioned plurality of individual regions differ in one direction. The exhaust gas piping located upstream of the exhaust deflection section has a bend, An exhaust gas rectifier wherein the opening ratio of the plurality of individual regions decreases in the direction in which the exhaust gas flows in the exhaust gas piping upstream of the bend.

2. The exhaust gas rectifier according to claim 1, wherein the opening ratio of the plurality of individual regions increases as you move from one side to the other in one direction.

3. The exhaust gas straightening device according to claim 2, wherein the opening of the individual region with the largest opening ratio among the plurality of individual regions is located on the other side of the central portion in one direction of the exhaust deflection portion.

4. The exhaust gas rectifier according to claim 3, wherein, among the plurality of individual regions, the individual region with the largest opening ratio is located on the other side of the other individual regions.

5. The exhaust gas rectifier according to claim 4, wherein the openings of the other individual regions have a longitudinal direction.

6. The exhaust gas rectifier according to claim 5, wherein the other individual regions have a plurality of openings of the same shape.

7. The exhaust gas straightening device according to claim 1, wherein the exhaust deflection portion has a shape that is symmetrical in a direction perpendicular to the one direction.

8. The exhaust gas straightening device according to claim 1, wherein the exhaust deflection portion has an asymmetrical shape in a direction perpendicular to the one direction.

9. The first exhaust gas piping to which the urea water injection device is attached, The system further comprises a second exhaust gas pipe located upstream of the first exhaust gas pipe, The exhaust gas piping located upstream of the exhaust deflection section is the second exhaust gas piping, The exhaust deflection section includes an exhaust deflection plate. The exhaust gas rectifier according to claim 1, wherein the exhaust deflection plate is located at a connection portion connecting the first exhaust gas pipe and the second exhaust gas pipe.

10. The urea water injection device is equipped with an exhaust deflection unit located upstream of the direction in which the exhaust gas flows. The exhaust deflection section includes a plurality of individual regions having openings through which the exhaust gas passes, The aforementioned multiple individual regions are arranged in a line in one direction, The aperture ratios of the aforementioned plurality of individual regions differ in one direction. The first exhaust gas piping to which the urea water injection device is attached, The system further comprises a second exhaust gas pipe located upstream of the first exhaust gas pipe, The exhaust deflection section includes an exhaust deflection plate. The exhaust deflection plate is located at the connection point that connects the first exhaust gas pipe and the second exhaust gas pipe. The aforementioned connection part is The first flange portion of the first exhaust gas piping, The second exhaust gas piping includes a second flange portion, The exhaust deflection plate is an exhaust gas straightening device installed between the first flange portion and the second flange portion.

11. The urea water injection device is equipped with an exhaust deflection unit located upstream in the direction in which the exhaust gas flows, The exhaust deflection section includes a plurality of individual regions having openings through which the exhaust gas passes, The aforementioned multiple individual regions are arranged in a line in one direction, The aperture ratios of the aforementioned plurality of individual regions differ in one direction. The first exhaust gas piping to which the urea water injection device is attached, The system further comprises a second exhaust gas pipe located upstream of the first exhaust gas pipe, The first exhaust gas piping has a first bend, The second exhaust gas pipe has a second bend, The urea water spray device is attached to the first bend, The exhaust deflection section is positioned closer to the first bend than the center between the first and second bends in the exhaust gas purification device.

12. The exhaust gas rectifier according to claim 1, wherein the one direction is the direction of gravity.

13. An exhaust gas rectifier according to any one of claims 1 to 12, DPF system and, An exhaust gas purification system comprising an SCR system including the urea water injection device.

14. The exhaust gas purification system according to claim 13, wherein the DPF system is located upstream of the exhaust gas rectifier.

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