SCR system and urine water tank

Abstract

To provide an SCR system comprising a configuration that further promotes the reduction action of an SCR catalyst.SOLUTION: An SCR system comprises: an SCR catalyst 1; a pipe 2 for flowing exhaust gas to the SCR catalyst 1; and a urea water injection nozzle 3 for injecting urea water into the pipe 2, where the pipe 2 is bent at approximately right angles on a downstream side where the exhaust gas flows into the SCR catalyst 1 and on an upstream side thereto so that the urea water injected into the pipe 2 is diffused and activated, two urea water injection nozzles 3 are provided, and the urea water is injected from opposing positions on the downstream part of the pipe 2.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an SCR system that utilizes an SCR catalyst. [Background technology]

[0002] Particulate matter emitted from the engine is collected by the DPF device, and the particulate matter that accumulates on the filter is burned by the high-temperature exhaust gas through an oxidation catalyst. After that, by adding urea water to the exhaust gas through the SCR system, ammonia reacts chemically with nitrogen oxides, reducing nitrogen and water.

[0003] This is a common practice for reducing NOx in exhaust gases. Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, it is desired to further promote the reduction action by adding urea water as described above.

[0005] The present invention takes into consideration such issues regarding reduction action and aims to provide an SCR system having a configuration that further promotes the reduction action. [Means for solving the problem]

[0006] The first aspect of the present invention is An SCR system including an SCR catalyst, a pipe for flowing exhaust gas to the SCR catalyst, and a urea water injection nozzle for injecting urea water into the pipe, The SCR system is characterized in that the urea water injected into the piping is diffused and activated.

[0007] The second aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, In the first SCR system of the present invention, two urea water injection nozzles are provided, and urea water is injected from opposing positions in the downstream piping portion.

[0008] The third aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, This is the first SCR system of the present invention, in which the downstream piping portion is formed in a spiral shape.

[0009] The fourth aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, In the first SCR system of the present invention, the urea water injection nozzle is attached near the bent portion and injects urea water toward the upstream side.

[0010] The fifth aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, This is a first SCR system of the present invention, in which a portion of the downstream piping is partially throttled.

[0011] The sixth aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, In the first SCR system of the present invention, a grid-shaped or spiral-shaped diffusion plate is disposed in the downstream piping.

[0012] The seventh aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, This is a first SCR system of the present invention, in which a diffusion plate is provided at the tip of the urea water injection nozzle.

[0013] The eighth aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, In a first SCR system of the present invention, an electric heating plate or an electric heating wire is disposed at the tip of the urea water injection nozzle or in the downstream piping.

[0014] The ninth aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion, In the first SCR system of the present invention, a fan for dispersing the injected urea water is provided in the piping.

[0015] The tenth aspect of the present invention is The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion, The downstream piping section is further bent, which is the first SCR system of the present invention.

[0016] The eleventh aspect of the present invention is 1. An SCR system used in an engine system having an intake manifold disposed on one side of an engine, an exhaust manifold disposed on the other side of the engine, and a flywheel disposed behind the engine, The SCR catalyst treats exhaust gas output from a DPF device that treats exhaust gas discharged from the engine, The DPF housing of the DPF device and the SCR housing of the SCR catalyst are configured as separate housings connected by the piping, The DPF housing is disposed above the engine, the SCR housing is disposed above the flywheel; The SCR system of the present invention is any one of first to tenth, wherein the piping from the DPF device to the SCR catalyst passes above the intake manifold, and the urea water injection nozzle is provided in a portion of the piping located above the intake manifold.

[0017] The twelfth aspect of the present invention is 1. An SCR system in an engine system having an intake manifold disposed on one side of an engine, an exhaust manifold disposed on the other side of the engine, and a flywheel disposed behind the engine, The DPF device treats exhaust gas discharged from the engine, and the SCR catalyst treats exhaust gas treated by the DPF device. The DPF housing of the DPF device and the SCR housing of the SCR catalyst are configured as separate housings connected by piping, The DPF housing is disposed above an exhaust manifold of the engine and parallel to a crankshaft of the engine, The SCR system is characterized in that the SCR housing is disposed above a flywheel located at the rear of the engine and perpendicular to the crankshaft.

[0018] The thirteenth aspect of the present invention is The exhaust gas is introduced into the DPF device from the rear side of the engine, and the exhaust port for the treated exhaust gas is disposed on the front side of the engine; This is an SCR system according to a twelfth aspect of the present invention, wherein a urea water injection nozzle is provided in a pipe between the exhaust port of the DPF device and the inlet of the SCR catalyst.

[0019] The fourteenth aspect of the present invention is An SCR system including an SCR catalyst, a pipe for passing exhaust gas from an engine to the SCR catalyst, and a urea water injection nozzle for injecting urea water into the pipe, a mixer having a rotating blade for dispersing the urea water injected into the pipe, The angle of the rotor blades relative to the exhaust gas is adjustable; The SCR system is characterized in that a control means adjusts the angle based on the temperature of the exhaust gas of the engine.

[0020] The fifteenth aspect of the present invention is An SCR system including an SCR catalyst, a pipe for passing exhaust gas from an engine to the SCR catalyst, and a urea water injection nozzle for injecting urea water into the pipe, The piping portion from the urea water injection nozzle to the SCR catalyst is U-shaped, a recovery mechanism for recovering urea water is provided at the lowest part of the U-shaped piping portion, The urea water recovered by the recovery mechanism is returned to the urea water tank via a filter and a pump. The urea water in the urea water tank is injected from the urea water injection nozzle, This SCR system is characterized in that a quality measurement sensor is provided in the piping between the recovery mechanism and the urea water tank to measure the quality of the flowing urea water, and if the quality is below a predetermined standard, the flow is switched to another treatment tank at a predetermined point downstream from the point where the quality is measured.

[0021] The sixteenth aspect of the present invention is An SCR system including an SCR catalyst, an upstream pipe for flowing exhaust gas from an engine to the SCR catalyst, and a downstream pipe for discharging exhaust gas treated by the SCR catalyst, The SCR catalyst is disposed so that its central axis is vertical, the exhaust gas enters the SCR catalyst from below, and the exhaust gas treated by the SCR catalyst is exhausted from the SCR catalyst in an upward direction, A tail pipe of a reducer pipe is placed over the upper end of the downstream pipe with a predetermined gap therebetween, A tray for receiving condensed water is disposed under the gap, A condensed water tank is provided to store the condensed water accumulated in the tray. In this SCR system, the condensate tank is provided with a drain.

[0022] The seventeenth aspect of the present invention is A urea water tank for storing urea water used in an SCR catalyst, which can be set in a tank case provided in each vehicle, The urea water tank is configured as a cassette type that can be easily removed from the tank case, The urea water tank and the tank case can be connected with one touch. Effect of the Invention

[0023] According to the present invention, it is possible to provide an SCR system having a configuration that further promotes the reduction action. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a block diagram of an SCR system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 3] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 4] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 5] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 6]FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 7] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 8] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 9] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 10] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 11] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 12] (A) and (B) are block diagrams of an SCR system according to another embodiment of the present invention. [Figure 13] (A) and (B) are block diagrams of an SCR system according to another embodiment of the present invention. [Figure 14] (A) and (B) are block diagrams of an SCR system according to another embodiment of the present invention. [Figure 15] (A) and (B) are block diagrams of an SCR system according to another embodiment of the present invention. [Figure 16] (A) and (B) are block diagrams of an SCR system according to another embodiment of the present invention. [Figure 17] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 18] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 19] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 20] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 21] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 22] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 23] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 24] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 25] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 26] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 27] Flowchart of an alternative embodiment of FIG. [Figure 28] (A) and (B) are block diagrams of an SCR system according to another embodiment of the present invention. [Figure 29] Flowchart of an alternative embodiment of FIG. [Diagram 30] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 31] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 32] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 33] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 34] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 35] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Diagram 36] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 37] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. [Figure 38] FIG. 1 is a block diagram of an SCR system according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0026] 1 is a diagram showing an SCR catalyst 1 and a pipe 2 that guides exhaust gas flowing from a DPF device to the SCR catalyst 1. A urea water injection nozzle 3 that injects urea water 4 is provided in the pipe 2, and the urea water 4 injected into the pipe 2 is configured to be diffused and activated.

[0027] That is, the pipe 2 is bent at approximately a right angle between the downstream side 2a, where the exhaust gas flows into the SCR catalyst 1, and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c so as to inject urea water 4 in the direction of the downstream side 2a.

[0028] The portion of the pipe 2 on the downstream side 2a is formed in a spiral shape 200. For example, the pipe 2 itself is spiral.

[0029] This promotes mixing of the exhaust gas and the urea water 4, improving the reduction rate in the SCR catalyst 1.

[0030] In Fig. 2, the pipe 2 is bent at a nearly right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1, and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c, but injects the urea water 4 in the upstream direction 2b. As a result, the urea water 4 is injected toward the exhaust gas flowing from the DPF device, which promotes mixing and improves the reduction rate of the SCR catalyst 1.

[0031] In Fig. 3, the pipe 2 is bent at a nearly right angle between the downstream side 2a where exhaust gas flows into the SCR catalyst 1 and the upstream side 2b, and two urea water injection nozzles 3 are provided to inject urea water 4 from opposing positions in the pipe 2 at the downstream side 2a. For example, in the drawing, the nozzles are injected from an upper position and an opposing lower position so that the nozzles collide with each other. As a result, the colliding urea water 4 is mixed with the exhaust gas flowing from the DPF device, improving the reduction rate of the SCR catalyst 1.

[0032] In FIG. 4, the pipe 2 is bent at a nearly right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1 and the upstream side 2b. The urea water injection nozzle 3 is attached near the bent part 2c and injects the urea water 4 in the direction of the downstream side 2a. A part of the downstream portion of the piping 2 is partially narrowed. That is, as shown in Fig. 4, a shielding plate 5a is erected on the inner wall of the piping so as to partially block the flow, thereby narrowing the flow path. Alternatively, as shown in Fig. 5, the piping 2 itself has a narrowed portion 5b. This increases the resistance to the exhaust gas in the narrowed portion of the flow path, promoting the mixing of the exhaust gas and the urea water 4, and improving the reduction rate in the SCR catalyst 1.

[0033] In Fig. 6, the pipe 2 is bent at a nearly right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1 and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c to inject the urea water 4 toward the downstream side 2a, and a lattice-shaped diffusion plate 6 is arranged on the part of the pipe 2 on the downstream side 2a. Alternatively, in Fig. 7, a spiral diffusion plate 7 is arranged on the part of the pipe 2 on the downstream side 2a. This promotes mixing of the exhaust gas and the urea water 4, improving the reduction rate in the SCR catalyst 1.

[0034] In Fig. 8, the pipe 2 is bent at a nearly right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1, and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c and injects the urea water 4 in the direction of the downstream side 2a, and a diffusion plate 8 is provided at the tip of the urea water injection nozzle 3. This allows the urea water 4 to be diffused more and mixed into the exhaust gas, which promotes mixing of the exhaust gas and the urea water 4 and improves the reduction rate in the SCR catalyst 1.

[0035] 9, the pipe 2 is bent at approximately a right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1, and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c and injects the urea water 4 towards the downstream side 2a, and an electric heating wire 9 is arranged in the part of the pipe 2 on the downstream side 2a. This increases the temperature of the flowing exhaust gas and improves the reduction rate of the SCR catalyst 1. Note that the same effect can be obtained by attaching an electric heating plate (not shown) to the tip of the urea water injection nozzle 3 instead of the electric heating wire 9.

[0036] In Fig. 10, the pipe 2 is bent at approximately a right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1 and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c and injects the urea water 4 towards the downstream side 2a. The bent part 2c is partially recessed, where a motor fan 10 is installed to stir the exhaust gas towards the downstream side 2a. The axial direction of the motor fan 10 and the axial direction of the downstream side 2a are in the same direction. The urea water injection nozzle 3 injects the urea water towards the downstream side 2a.

[0037] 11, the pipe 2 is bent at a nearly right angle between the downstream side 2a where the exhaust gas flows into the SCR catalyst 1 and the upstream side 2b, and the urea water injection nozzle 3 is attached near the bent part 2c and injects the urea water 4 toward the downstream side 2a. Furthermore, the part of the pipe 2 on the downstream side 2a is further bent. That is, a shielding part 2d is provided downstream from the bent part 2c to prevent the exhaust gas from passing through, but an opening S is cut into the bottom surface (on the drawing) 2e of the downstream side 2a, and the exhaust gas that can no longer pass through flows downward (on the drawing) from the opening S and into the SCR catalyst 1 through the most downstream side 2f.

[0038] Since an additional bent portion is provided in this manner, the mixing of the urea water 4 and the exhaust gas is promoted, and the reduction rate of the SCR catalyst 1 is improved.

[0039] Next, another embodiment of the present invention will be described.

[0040] 12(A) and (B) show an SCR system using each of the above SCR systems. In FIG. 12(A) and (B), an intake manifold 13 is disposed on one side of an engine 12, an exhaust manifold 14 is disposed on the other side of the engine 12, and a flywheel 15 is disposed behind the engine 12.

[0041] The SCR catalyst 1 processes exhaust gas output from a DPF device 16 which processes exhaust gas discharged from an engine 12, and is configured as separate housings, with a DPF housing 16a of the DPF device 16 and an SCR housing 1a of the SCR catalyst 1 connected by piping 2.

[0042] Here, the DPF housing 16a is disposed above the engine 12, and the SCR housing 1a is disposed above the flywheel 15. Furthermore, piping 2 from the DPF device 16 to the SCR catalyst 1 is provided on the intake manifold 13 side, and a urea water injection nozzle 3 is provided in a portion of the piping 2 located above the intake manifold 13. Reference numeral 17 denotes a dosing module that supplies urea water 4 to the urea water injection nozzle 3. This dosing module and other urea water related parts are also disposed on the intake manifold 13 side.

[0043] In this embodiment, by making the DPF housing 16a and the SCR housing 1a separate housings, it is possible to utilize the spaces above the engine 12 and the flywheel 15. In addition, by providing a part of the pipes 2 connecting the DPF device 16 and the SCR catalyst 1 and the urea water injection nozzle 3 on the intake manifold 13, it is possible to prevent early deterioration of the quality of the urea water 4 due to exposure to high temperatures.

[0044] Next, another embodiment of the present invention will be described.

[0045] 13(A) and (B) show an engine system in which an intake manifold 13 is disposed on one side of the engine 12, an exhaust manifold 14 is disposed on the other side of the engine 12, and a flywheel 15 is disposed behind the engine 12.

[0046] The SCR catalyst 1 processes exhaust gas output from a DPF device 16 that processes exhaust gas discharged from an engine 12, and is configured as separate housings, with a DPF housing 16a of the DPF device 16 and an SCR housing 1a of the SCR catalyst 1 connected by a pipe 2. Reference numeral 18 denotes a DOC.

[0047] Here, the DPF housing 16a is disposed above the exhaust manifold 14 and parallel to the crankshaft 19. Reference numeral 16b denotes the axis of the DPF housing 16a. The SCR housing 1a is disposed above the flywheel 15 at the rear of the engine 12 and perpendicular to the crankshaft 19.

[0048] As a result, by making the DPF housing 16a and the SCR housing 1a separate housings, the spaces above the exhaust manifold 14 and above the flywheel 15 can be used to mount the SCR system.

[0049] FIG. 14 shows an example in which the mounting position of the urea water injection nozzle 3 is specified in the embodiment of FIG.

[0050] That is, an inlet 16c for introducing exhaust gas into the DPF device 16 is located on the rear side of the engine 12, and an outlet 16d for exhausting the treated exhaust gas is located on the front side of the engine 12. A urea water injection nozzle 3 is provided in a pipe 2 between an exhaust outlet 16d of the DPF device 16 and an inlet of the SCR catalyst 1.

[0051] This allows the distance from the outlet 16d of the DPF device 16 to the inlet of the SCR catalyst 1 to be long, making it possible to provide space for mounting the urea water injection nozzle 3. In other words, by attaching the urea water injection nozzle 3 near the outlet 16d of the DPF device 16, the distance to the SCR catalyst 1 is long, so that the urea water 4 and exhaust gas are mixed sufficiently, thereby improving the reduction rate.

[0052] Next, another embodiment of the present invention will be described.

[0053] 15(A) and (B), the SCR system includes an SCR catalyst 1, a pipe 2 through which exhaust gas from the engine flows to the SCR catalyst 1, and a urea water injection nozzle 3 that injects urea water 4 into the pipe 2. The SCR system also includes a mixer 21 having rotating blades 20 that diffuse the urea water 4 injected into the pipe 2.

[0054] The angle of the rotor blades 20 relative to the exhaust gas is adjustable, and the control means 22 adjusts the angle based on the temperature of the exhaust gas from the engine in an SCR system.

[0055] If the rotor blades 20 are angled upright with respect to the flow of exhaust gas, the flow becomes more difficult, and if they are angled down, the flow becomes easier. This control is performed by the control means 22 according to the operating state of the engine.

[0056] For example, when the engine is cold (when the temperature is low), the exhaust gas temperature is low and the temperature of the SCR catalyst is also low, resulting in poor activity (NOx purification), but with the above-mentioned configuration, the rotating blades 20 of the mixer 21 are raised at low temperatures to strengthen turbulence and promote mixing of the urea water 4. In addition, increasing the exhaust pressure increases the exhaust gas temperature, promoting activity of the SCR catalyst.

[0057] After warming up, the angle of the rotating blades 20 of the mixer 21 can be tilted to reduce exhaust resistance and improve fuel efficiency.

[0058] FIG. 16 shows another embodiment of the present invention.

[0059] That is, two mixers 24, 26 are provided in parallel upstream of the SCR catalyst 1, and the urea water injection nozzle 3 is provided upstream of the two mixers 24, 26. The mixers 24, 26 are provided with rotating vanes 23, 25, one of which has a fixed rotating vane 23, while the phase of the other rotating vane 25 can be changed as desired. The control means 22 controls the phase of the rotating vane 25 using an ECU according to the engine operating state.

[0060] That is, at low temperatures, the rotor blades 23 of the fixed side mixer 24 and the rotor blades 25 of the rotor side mixer 26 rotate the rotor side mixer 26 in phase so that the effective area AR of the pipe 2 becomes smaller, thereby strengthening the turbulence and promoting the mixing of the urea water 4 (see the upper right diagram in FIG. 16). Also, increasing the exhaust pressure increases the exhaust temperature, promoting the activity of the SCR catalyst.

[0061] After warming up, in order to increase the effective area AR of the pipe 2, the rotating-side mixer 26 is rotated in phase so that the rotating blades 23, 25 of the fixed-side mixer 24 and the rotating-side mixer 26 overlap, thereby reducing exhaust resistance and improving fuel efficiency (see the diagram at the bottom right of Figure 16).

[0062] Next, another embodiment of the present invention will be described.

[0063] 17, the SCR system includes an SCR catalyst 1, a pipe 2 through which exhaust gas from an engine flows to the SCR catalyst 1, and a urea water injection nozzle 3 that injects urea water 4 into the pipe 2, in which the portion of the pipe 2 from the urea water injection nozzle 3 to the SCR catalyst 1 is U-shaped, and a recovery mechanism 31 for recovering the urea water 4 is provided at the bottom of the U-shaped pipe portion. Furthermore, a drain 32 is provided at the bottom of the recovery mechanism 31. Reference numeral 30 denotes a urea water tank.

[0064] Originally, when the urea water 4 is injected when the engine is cold or when a large amount of urea water 4 is injected to improve NOx purification, if the urea water 4 accumulates in the exhaust piping 2, there are concerns that it may cause urea deposition, piping corrosion, and deterioration of the SCR catalyst. However, by lowering the exhaust piping 2 after the urea water injection nozzle 3 as in the above configuration, the urea water 4 that has adhered to the wall surface can be collected and discharged during maintenance, thereby suppressing the effects of the accumulation of the urea water 4.

[0065] Figure 18 shows a modified example of the embodiment shown in Figure 17, in which the urea water 4 recovered by the recovery mechanism 31 is returned to the urea water tank 30 via a filter 33 and a pump 34, and the urea water 4 in the urea water tank 30 is sprayed from the urea water spray nozzle 3.

[0066] This allows the urea water 4 adhering to the wall surface to be collected and returned to the urea water tank 30, thereby reducing the consumption of the urea water 4.

[0067] Fig. 19 shows a further modification of the modification shown in Fig. 18, in which a quality measurement sensor 35 for measuring the quality of the flowing urea water 4 is provided in the piping between the pump 34 downstream from the recovery mechanism 31 and the urea water tank 30, and a valve 36 for switching the flow to another treatment tank 37 at a predetermined point downstream from the point where the quality is measured if the quality is below a predetermined standard is provided.

[0068] This makes it possible to prevent the low-quality urea water 4 from being reduced.

[0069] FIG. 20 shows a further modified example of the modified example of FIG. 19, in which a water level gauge is provided in the tank 37, and when the amount of low-quality urea reaches a certain level or more, an announcement is made to the operator to discharge the urea.

[0070] Next, another embodiment of the present invention will be described.

[0071] In Figure 21, the SCR system comprises an SCR catalyst 1, an upstream piping 2 that flows exhaust gas from the engine to the SCR catalyst 1, and a downstream piping 39 that exhausts exhaust gas treated by the SCR catalyst 1, in which the SCR catalyst 1 is positioned so that its central axis is vertical, exhaust gas enters the SCR catalyst 1 from below, and exhaust gas treated by the SCR catalyst 1 is exhausted upward from the SCR catalyst 1, and a tail pipe 40 of a reducer piping is placed over the upper end of the downstream piping 39 with a specified gap G between them.

[0072] Originally, when the SCR catalyst 1 is mounted vertically, the tip of the tail pipe 40 is at the top of the vehicle, so there is a possibility that condensed water 400 will spray out from above after the engine is started. However, with the above-mentioned configuration, by providing the tail pipe 40 of the reducer piping downstream of the SCR catalyst 1, it is possible to prevent the condensed water 400 traveling inside the piping from flowing to the tip of the tail pipe 40, and by introducing outside air from the reducer piping, it is possible to lower the exhaust temperature.

[0073] FIG. 22 shows a modification of FIG. 21, in which a return 41 is provided in the reducer piping.

[0074] Thus, by providing a reducer pipe downstream of the SCR catalyst 1 and a return pipe 41 inside, it is possible to prevent the condensed water 400 traveling inside the pipe from flowing up to the tip of the tail pipe 40.

[0075] Figure 23 is a modified example of Figure 21, and in addition, a tray 42 for receiving condensed water is placed under the gap G, a condensed water tank 43 is provided for storing condensed water 400 that accumulates in the tray 42, and a drain 44 is provided in the condensed water tank 43.

[0076] Originally, the condensed water 400 discharged from downstream of the SCR is not pure and may have adverse effects on the field and crops. However, by collecting the condensed water 400, it is possible to prevent the condensed water from having adverse effects on the field and crops.

[0077] Next, an embodiment of the urea water tank of the present invention will be described.

[0078] FIG. 24 shows a urea water tank 30 for storing urea water 4 used in an SCR catalyst 1, which can be set in a tank case 46 provided in each vehicle 45. The urea water tank 30 is configured as a cassette that can be easily removed from the tank case 46, and the connection between the urea water tank 30 and the tank case 46 can be made with a single touch.

[0079] The tank case 46 and the urea water tank 30 of each vehicle 45 are of standardized specifications and can be easily removed.

[0080] Since the frequency of use of agricultural machinery varies depending on the season, there is a concern that the refilled urea water 4 may not be used up and its quality may deteriorate during storage. However, with the above-described configuration, the same urea water tank can be attached to various vehicles, so that the urea water 4 can be used up before quality deterioration due to long-term storage occurs.

[0081] Fig. 25 shows a specific example of the tank case 46 and the urea water tank 30 of Fig. 24. That is, the urea water tank is provided with a quality sensor 47 with a float function. 48 is a one-touch adapter.

[0082] Originally, the frequency of use of agricultural machinery varies depending on the season, and so there was a concern that the refilled urea water 4 would not be used up and its quality would deteriorate during storage. However, with the above-described configuration, the same urea water tank can be attached to and used by various vehicles, so that the urea water 4 can be used up before quality deterioration due to long-term storage occurs.

[0083] 26 and 27 show another modified example, in which the control means 22 measures the change in the remaining amount by a remaining amount sensor 49, and the ECU calculates the period since the urea water 4 was refilled. If the calculated period exceeds a certain period, it is determined that the quality of the urea water 4 has deteriorated, and the user is prompted to replace the urea water.

[0084] Originally, if the urea water 4 is stored for a long period of time, the urea water 4 will deteriorate. However, with the above-described configuration, if the remaining amount of the urea water 4 has not increased, it can be determined that the urea water 4 has been stored for a long period of time without being replenished, and therefore the user can be notified of the deterioration in quality of the urea water 4 due to the long-term storage of the urea water 4.

[0085] 28(A), (B) and 29 show another modified example, in which a sensor 50 for detecting opening and closing is provided at the supply port 30a of the tank 30, and the period since the supply port 30a was opened is calculated by the ECU. When the calculated period exceeds a certain period, it is determined that the quality of the urea water 4 has deteriorated, and the user is prompted to replace the urea water 4. As a result, if the replenishing port 30a is not opened, it can be determined that the urea water 4 has not been replenished and has been stored for a long period of time, and the user can be notified of the deterioration of the quality of the urea water 4 due to the long-term storage of the urea water 4.

[0086] Next, another embodiment of the present invention will be described.

[0087] In Fig. 30, two urea water piping systems are provided from the urea water tank 30 to the dosing module 52. One pipe 54 is routed in front of the radiator 56. The other pipe 53 is routed behind the radiator 56 (behind the engine 12). Reference numeral 55 denotes a hood (bonnet).

[0088] Originally, there are concerns that the urea water 4 may have problems due to freezing at low temperatures and quality deterioration at high temperatures, but by utilizing the switching valve 51 and using the piping 53 behind the radiator 56 where the ambient temperature is high at low temperatures, problems due to the urea water freezing can be prevented, and by using the piping 54 in front of the radiator 56 where the ambient temperature is low at high temperatures, early deterioration of the urea water 4 can be prevented.

[0089] Fig. 31 shows a modification of Fig. 30, in which the SCR catalyst 1 is provided outside the hood 55, and two urea water piping systems are provided from the urea water tank 30 to the dosing module 52. One system, 53, is routed inside the hood 55. The other system, 54, is routed outside the vehicle.

[0090] There are concerns that the urea water 4 may have problems due to freezing at low temperatures and may deteriorate in quality at high temperatures. However, by using the piping 53 inside the hood 55 where the ambient temperature is high at low temperatures, problems due to the urea water freezing can be prevented, and by using the piping 54 outside the vehicle where the ambient temperature is low at high temperatures, early deterioration of the urea water 4 can be prevented.

[0091] Next, another embodiment will be described.

[0092] In FIG. 32, the amount of urea water injected from the urea water injection nozzle 3 is integrated for a certain period of time, and when the integrated value is equal to or less than a certain value, it is determined that the condition is low load and low temperature, and a lamp 58 on a meter panel 57 is turned on.

[0093] Originally, there is a risk that the urea water injection nozzle 3 will deteriorate if the SCR system is operated continuously for a long period of time under low load and low temperature conditions, but it is possible to make the user aware that the operation is under a long period of time under low load and low temperature conditions.

[0094] Figure 33 is a modification of Figure 32, which issues a regeneration request to perform manual regeneration in order to refresh the urea water injection nozzle 3. Reference numeral 59 denotes a manual regeneration switch. By performing manual regeneration by, for example, increasing the engine speed, the urea water injection nozzle 3 is exposed to high temperatures and can be purified.

[0095] Fig. 34 is a modification of Fig. 33, in which manual regeneration is changed to automatic regeneration, and the urea water injection nozzle 3 can be automatically cleaned. Reference numeral 60 denotes a regeneration lamp. By performing automatic regeneration, the urea water injection nozzle 3 can be exposed to high temperatures and cleaned.

[0096] Next, another embodiment will be described.

[0097] In FIG. 35, the urea water 4 used is slightly less than 70% water and will freeze in cold regions, so an electric heater 62 is installed in the piping 61 from the tank 30 to the urea water injection nozzle 3 to prevent freezing.

[0098] Fig. 36 shows a modification of Fig. 35, in which a pipe 63 is installed so that warm coolant after cooling the engine 12 flows through the pipe 61 from the tank 30 to the urea water injection nozzle 3 to prevent freezing. Since the coolant for the engine 12 does not freeze, this prevents the urea water 4 from freezing. Furthermore, the increase in the temperature of the coolant leads to an improvement in the reduction rate.

[0099] Fig. 37 shows a modification of Fig. 35, in which an antifreeze tank 64 for preventing the engine from freezing is installed next to the urea water tank 30. Piping is installed from the urea water tank 30 to the urea water injection nozzle 3 so that antifreeze liquid flows through the piping for preventing freezing. This makes it possible to prevent the urea water 4 from freezing.

[0100] Fig. 38 is a modification of Fig. 37, in which an electric heater 65 is provided in a freeze prevention tank 64. Therefore, the temperature of the urea water 4 rises, and the reduction rate is improved.

[0101] The SCR system and urea solution tank of the present invention are not limited to agricultural machinery such as tractors, rice transplanters, and combine harvesters, but can also be applied to general vehicles. [Industrial Applicability]

[0102] The present invention can realize an SCR system with a configuration that further promotes the reduction effect, making it ideal for tractors and the like. [Explanation of symbols]

[0103] 1 SCR catalyst 2 Piping 3 Urea injection nozzle 4 Urea water 5a Shielding plate 5b Squeezing section 12 Engine 13 Intake manifold 14 Exhaust manifold 15 Flywheel 16 DPF device 17 Dosing Module 30 Urea tank AR Effective Area G Gap S opening

Claims

1. An SCR system including an SCR catalyst, a pipe for flowing exhaust gas to the SCR catalyst, and a urea water injection nozzle for injecting urea water into the pipe, The SCR system is characterized in that the urea water injected into the pipe is diffused and activated.

2. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, 2. The SCR system according to claim 1, wherein the urea water injection nozzle is provided in two, and the urea water is injected from opposing positions in the downstream pipe portion.

3. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, 2. The SCR system of claim 1, wherein the downstream portion of the piping is formed in a helical shape.

4. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, 2. The SCR system according to claim 1, wherein the urea water injection nozzle is attached near the bent portion and injects the urea water in the upstream direction.

5. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, 2. The SCR system of claim 1, wherein a portion of the downstream piping section is partially throttled.

6. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, 2. The SCR system according to claim 1, further comprising a grid-shaped or spiral-shaped diffuser plate disposed in a downstream portion of the piping.

7. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, 2. The SCR system according to claim 1, wherein a diffusion plate is provided at a tip of said urea water injection nozzle.

8. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion and injects the urea water in the downstream direction, 2. The SCR system according to claim 1, further comprising an electric heating plate or electric heating wire disposed at the tip of the urea water injection nozzle or in the downstream pipe.

9. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion, 2. The SCR system according to claim 1, further comprising a fan disposed in said piping for dispersing the injected urea water.

10. The pipe is bent at a substantially right angle between a downstream side where the exhaust gas flows into the SCR catalyst and a further upstream side, The urea water injection nozzle is attached near the bent portion, The SCR system of claim 1 , wherein the downstream piping section is further bent.

11. 1. An SCR system used in an engine system having an intake manifold disposed on one side of an engine, an exhaust manifold disposed on the other side of the engine, and a flywheel disposed behind the engine, The SCR catalyst treats exhaust gas output from a DPF device that treats exhaust gas discharged from the engine, The DPF housing of the DPF device and the SCR housing of the SCR catalyst are configured as separate housings connected by the piping, The DPF housing is disposed above the engine, the SCR housing is disposed above the flywheel, 11. The SCR system according to claim 1, wherein the piping from the DPF device to the SCR catalyst passes above the intake manifold, and the urea water injection nozzle is provided in a portion of the piping located above the intake manifold.

12. 1. An SCR system in an engine system having an intake manifold disposed on one side of an engine, an exhaust manifold disposed on the other side of the engine, and a flywheel disposed behind the engine, The vehicle is provided with a DPF device for treating exhaust gas discharged from the engine, and an SCR catalyst for treating exhaust gas treated by the DPF device, The DPF housing of the DPF device and the SCR housing of the SCR catalyst are configured as separate housings connected by piping, The DPF housing is disposed above an exhaust manifold of the engine and parallel to a crankshaft of the engine, The SCR system is characterized in that the SCR housing is disposed above a flywheel located at the rear of the engine and perpendicular to the crankshaft.

13. The exhaust gas is introduced into the DPF device from the rear side of the engine, and the exhaust port for the treated exhaust gas is disposed on the front side of the engine; The SCR system according to claim 12, further comprising a urea water injection nozzle provided in a pipe between the exhaust port of the DPF device and the inlet of the SCR catalyst.

14. An SCR system including an SCR catalyst, a pipe for passing exhaust gas from an engine to the SCR catalyst, and a urea water injection nozzle for injecting urea water into the pipe, a mixer having a rotating blade for dispersing the urea water injected into the pipe, The angle of the rotor blades relative to the exhaust gas is adjustable; a control means for adjusting said angle based on a temperature of the exhaust gas of said engine.

15. An SCR system including an SCR catalyst, a pipe for passing exhaust gas from an engine to the SCR catalyst, and a urea water injection nozzle for injecting urea water into the pipe, A piping portion from the urea water injection nozzle to the SCR catalyst is U-shaped, a recovery mechanism for recovering urea water is provided at the lowest part of the U-shaped piping portion, The urea water recovered by the recovery mechanism is returned to the urea water tank via a filter and a pump. The urea water in the urea water tank is injected from the urea water injection nozzle, The SCR system is characterized in that a quality measurement sensor is provided in piping between the recovery mechanism and the urea water tank to measure the quality of the flowing urea water, and if the quality is below a predetermined standard, the flow is switched to another treatment tank at a predetermined point downstream from the point where the quality is measured.

16. An SCR system including an SCR catalyst, an upstream pipe for flowing exhaust gas from an engine to the SCR catalyst, and a downstream pipe for discharging exhaust gas treated by the SCR catalyst, the SCR catalyst is disposed so that its central axis is vertical, the exhaust gas enters the SCR catalyst from below, and the exhaust gas treated by the SCR catalyst is exhausted from the SCR catalyst in an upward direction, A tail pipe of a reducer pipe is placed over the upper end of the downstream pipe with a predetermined gap therebetween, A tray for receiving condensed water is disposed under the gap, A condensed water tank is provided to store the condensed water accumulated in the tray. An SCR system in which the condensate tank is provided with a drain.

17. A urea water tank for storing urea water used in an SCR catalyst, the urea water tank being capable of being set in a tank case provided in each vehicle, The urea water tank is configured as a cassette type that can be easily removed from the tank case, The urea water tank and the tank case can be connected with one touch.

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