Exhaust purification device

Abstract

To provide an exhaust purification device capable of removing deposit of urea which has accumulated in the vicinity of a tip part of an injector and a mixer.SOLUTION: An exhaust purification device includes: an injector for jetting urea water to an exhaust path of an exhaust gas; a mixer for mixing the urea water with the exhaust gas; and a converter provided on the downstream of the mixer, and for reducing and purifying nitrogen oxide in the exhaust gas using ammonia generated by mixing. In a state where the exhaust purification device is mounted on a vehicle body, the mixer is positioned further on the rear side of the vehicle than the injector, and is positioned further on the front side of the vehicle than the converter. In a mounted state, the converter extends from the front to the back of the vehicle. In the mounted state, the converter is inclined in such a manner that a height of the rear side of the vehicle from the ground is higher than a height of the front side of the vehicle from the ground, so that a liquid accumulated at a bottom part of the converter by liquefaction reaches the injector via the mixer by the deceleration of the vehicle.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to an exhaust gas purification device for purifying exhaust gas.

Background Art

[0002] Conventionally, as disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2018-2039 (Patent Document 1), an exhaust gas purification device that purifies exhaust gas using a selective reduction catalyst is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a vehicle repeatedly travels at a low load, in the exhaust gas purification device, urea deposits accumulate on the vicinity of the tip of the injector that injects aqueous urea solution and on a mixer that mixes the injected aqueous urea solution and exhaust gas. When urea deposits accumulate, the aqueous urea solution and the exhaust gas cannot be efficiently mixed. As a result, the purification efficiency of the exhaust gas decreases.

[0005] The present disclosure has been made in view of the above problems, and provides an exhaust gas purification device capable of removing urea deposits accumulated on the vicinity of the tip of the injector and the mixer.

Means for Solving the Problems

[0006] According to an aspect of the present disclosure, an exhaust gas purification device that purifies exhaust gas discharged from an internal combustion engine of a vehicle traveling on the ground includes an injector that injects aqueous urea into an exhaust gas discharge path, a mixer that is provided in the discharge path in a state facing the injector and mixes the injected aqueous urea with the exhaust gas, and a converter that is provided downstream of the mixer in the discharge path and reduces and purifies nitrogen oxides in the exhaust gas using ammonia generated by the mixing. The mixer is located behind the vehicle relative to the injector and in front of the vehicle relative to the converter in a mounted state where the exhaust gas purification device is attached to the vehicle body. The converter extends from the front to the rear of the vehicle in the mounted state. The converter is inclined in the mounted state such that the height from the ground on the rear side of the vehicle is higher than the height from the ground on the front side of the vehicle so that the liquid accumulated at the bottom of the converter by liquefaction reaches the injector via the mixer when the vehicle decelerates.

[0007] Preferably, the inclination angle in the mounted state is 5 degrees or more and 10 degrees or less. Preferably, in the mounted state, the exhaust gas in which nitrogen oxides are reduced and purified by the converter is discharged from the muffler of the vehicle to the outside of the vehicle. The number of converters between the mixer and the muffler is one.

[0008] Preferably, the converter has a first end on the mixer side and a second end on the rear side of the vehicle relative to the first end in the mounted state. The exhaust gas purification device further includes a first pipe that houses the mixer and a second pipe that is connected to the second end of the converter. A first opening for communicating with the first pipe is formed at the first end. A second opening for communicating with the second pipe is formed at the second end. In the mounted state, the lower end of the first opening is lower than the lower end of the second opening.

[0009] Preferably, the position of the first opening in the converter and the inclination angle in the mounted state are set such that the liquid level height is lower than the lower end of the first opening when the vehicle stops.

Advantages of the Invention

[0010] According to the present disclosure, it becomes possible to remove deposits of urea deposited near the tip of the injector and in the mixer.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0013] FIG. 1 is a side view of the vehicle. As shown in FIG. 1, the vehicle 1 travels on the ground R. The vehicle 1 includes a body (main body of the vehicle) 10, an engine (internal combustion engine) 20, front wheels 31, rear wheels 32, an exhaust gas purification device 40, and a muffler 50.

[0014] The exhaust gas purification device 40 purifies the exhaust gas discharged from the engine 20 of the vehicle 1. The exhaust gas purification device 40 is attached to the lower part of the body 10. The exhaust gas purification device 40 includes a tank 401, a pump 402, a pipe 403, a pipe 404, an injector 405, a pipe 406, a converter 407, and a pipe 408.

[0015] The pipe 403 is connected to the pipe 404. The pipe 404 is connected to the injector 405. The injector 405 is connected to the pipe 406. One end of the pipe 406 is connected to the engine 20. The other end of the pipe 406 is connected to the converter 407. The converter 407 is connected to the pipe 408. The pipe 408 is connected to the muffler 50.

[0016] The injector 405 is attached in front of the vehicle 1 with respect to the converter 407. The converter 407 extends from the front to the rear of the vehicle 1. The converter 407 is attached behind the vehicle 1 with respect to the pipe 406. The converter 407 is attached in front of the vehicle 1 with respect to the pipe 408. The muffler 50 is attached behind the vehicle 1 with respect to the pipe 408.

[0017] The tank 401 stores the aqueous urea solution. The pump 402 sends out the aqueous urea solution in the tank 401 to the pipe 403. Thereafter, the aqueous urea solution is sent to the injector 405 via the pipe 404. The engine 20 discharges the exhaust gas into the pipe 406.

[0018] The injector 405 injects the aqueous urea solution into the exhaust gas discharge path. The injector 405 injects the aqueous urea solution into the pipe 406. The injector 405 injects the aqueous urea solution to the rear side of the vehicle 1. The aqueous urea solution is sent to the converter 407 via the pipe 406.

[0019] The exhaust gas discharge path to the outside of the vehicle 1 (hereinafter also referred to as "outside the vehicle") of the exhaust gas is in the order of the pipe 406, the converter 407, the pipe 408, and the muffler 50. Thus, the exhaust gas in which nitrogen oxides are reductively purified by the converter 407 is discharged to the outside of the vehicle from the muffler 50.

[0020] Note that the pipe 406 is an example of the "first pipe" of the present disclosure. The pipe 408 is an example of the "second pipe" of the present disclosure.

[0021] FIG. 2 is a partial cross-sectional view for explaining the inside of the pipe 406. As shown in FIG. 2, the pipe 406 has a first portion 461, a second portion 462, and a third portion 463.

[0022] The first portion 461 is connected to the engine 20. The second portion 462 is connected to the first portion 461 and the third portion 463. The first portion 461 is located on the front side of the vehicle 1 with respect to the second portion 462. The second portion 462 is located on the front side of the vehicle 1 with respect to the third portion 463.

[0023] An opening 451 for attaching the injector 405 is formed in the first portion 461. A mixer 409 is accommodated inside the second portion 462. The mixer 409 is also referred to as a dispersion plate.

[0024] The tip of the injector 405 is accommodated inside the pipe 406. The injector 405 injects the urea water U to the rear side of the vehicle 1 inside the pipe 406. The injector 405 injects the urea water U toward the mixer 409.

[0025] The mixer 409 is provided in the discharge path V in a state facing the injector 405. In this example, the central axis J1 of the injector 405 and the central axis J2 of the mixer 409 extend in the front-rear direction of the vehicle 1. In this example, in the side view of the vehicle 1, the central axis J1 of the injector 405 and the central axis J2 of the mixer 409 are at the same height. The central axis J1 and the central axis J2 overlap in the front view of the vehicle.

[0026] The mixer 409 mixes the aqueous urea U injected from the injector 405 with the exhaust gas sent from the engine 20. In FIG. 2, the aqueous urea U is indicated by a plurality of solid circles. Ammonia is generated by the mixing of the aqueous urea U and the exhaust gas. In FIG. 2, the aqueous urea U is diffused on the downstream side (the rear side of the vehicle 1) from the mixer 409.

[0027] In the attached state where the exhaust gas purification device 40 is attached to the vehicle 1 as shown in FIG. 1, the mixer 409 is located behind the vehicle 1 from the injector 405 and in front of the vehicle 1 from the converter 407.

[0028] The converter 407 has a housing 470. A selective catalytic reduction (SCR) catalyst described later is housed in the housing 470. The converter 407 is provided downstream of the mixer 409 in the exhaust path V. The converter 407 reduces and purifies nitrogen oxides (Nox) in the exhaust gas using the ammonia generated by the above mixing.

[0029] In this example, the exhaust gas purification device 40 includes only one converter 407. Specifically, the number of converters 407 between the mixer 409 and the muffler 50 (FIG. 1) is one.

[0030] By the way, the aqueous urea U injected from the injector 405 accumulates at the vicinity of the tip of the injector 405 and the mixer 409 over time. The deposit by the aqueous urea is also referred to as "urea deposit". The urea deposit is water-soluble. The urea deposit is likely to occur particularly when the vehicle 1 repeatedly runs at a low load.

[0031] FIG. 3 is a diagram showing the urea deposit accumulated in the mixer 409. As shown in FIG. 3, urea deposits 900 are accumulated on the surface of the mixer 409. Specifically, many urea deposits 900 are accumulated on the surface on the front side (the injector 405 side) of the mixer 409.

[0032] More specifically, most of the aqueous urea U injected from the injector 405 is supplied to the lower side rather than the upper side of the mixer 409 due to the flow of the exhaust gas from the engine 20 and gravity. Therefore, many urea deposits 900 accumulate on the lower side rather than the upper side of the mixer 409.

[0033] FIG. 4 is a diagram for explaining the converter 407. As shown in FIG. 4, the converter 407 is inclined such that the height from the ground R on the rear side of the vehicle 1 is higher than the height from the ground R on the front side of the vehicle 1.

[0034] Although details will be described later, the converter 407 is inclined such that the liquid accumulated at the bottom of the converter 407 reaches the injector 405 via the mixer 409 (FIG. 2) due to the deceleration of the vehicle 1. The liquid is generated by the exhaust gas and vaporized urea in the converter 407 being cooled after the engine 20 stops. The liquid is also referred to as "condensate".

[0035] An opening 4071 and an opening 4072 are formed in the converter 407. The opening 4071 is an opening on the front side of the vehicle 1 relative to the opening 4072. The opening 4071 is an opening for the converter 407 to communicate with the pipe 406 (FIG. 1). The opening 4072 is an opening for the converter 407 to communicate with the pipe 408 (FIG. 1).

[0036] In a state where the exhaust gas purification device 40 is attached to the body 10 (the state shown in FIG. 1), the lower end P1 of the opening 4071 is lower than the lower end P2 of the opening 4072. The exhaust gas enters the converter 407 from the opening 4071, is reductively purified by the selective reduction catalyst, and then is discharged from the opening 4072 to the pipe 408.

[0037] Specifically, in this example, the housing 470 of the converter 407 includes a first part 471, a second part 472, a third part 473, a fourth part 474, and a fifth part 475 from the upstream side to the downstream side of the exhaust gas discharge path V. The interior of each of the first to fifth parts 471 to 475 is a cavity.

[0038] The first part 471 is the end on the mixer 409 side in the converter 407. The first part 471 is connected to the pipe 406. The first part 471 is cylindrical. An opening 4071 is formed in the first part 471.

[0039] The second part 472 is continuous with the first part 471. The second part 472 has a shape with a thickness on the outer peripheral surface of a frustum of an oblique cone. The opening area on the first part 471 side of the second part 472 is smaller than the opening area on the third part 473 side.

[0040] The third part 473 is continuous with the second part 472. The third part 473 is cylindrical. Therefore, in the third part 473, the opening area on the second part 472 side is the same as the opening area on the fourth part 474 side. A selective reduction catalyst 479 (see FIG. 6) is installed inside the third part 473.

[0041] The virtual line L1 is the central axis of the third part 473. Note that the central axis J3 is the central axis of the entire converter 407. A part of the central axis J3 and the virtual line L1 overlap. The virtual line L2 is a line parallel to the ground R.

[0042] The angle θ formed by the virtual line L1, the virtual line L2, and the ground R indicates the inclination angle of the converter 407. Preferably, the angle θ is 5 degrees or more and 10 degrees or less. More preferably, the angle θ is 7 degrees. The value of θ is determined in advance according to the shape of the converter 407, the amount of liquid accumulated at the bottom of the converter 407, etc.

[0043] The fourth part 474 is continuous with the third part 473. The fourth part 474 has the same shape as the second part 472, with a thickness on the outer peripheral surface of a frustum of an oblique cone. The opening area on the third part 473 side of the fourth part 474 is larger than the opening area on the fifth part 475 side.

[0044] The fifth part 475 is continuous with the fourth part 474. The fifth part 475 is the end part on the rear side of the vehicle 1 in the converter 407 relative to the first part 471. The fifth part 475 is connected to the pipe 408. The fifth part 475 is cylindrical, similar to the first part 471. An opening 4072 is formed in the fifth part 475.

[0045] Note that the opening 4071 is an example of the "first opening" of the present disclosure. The opening 4072 is an example of the "second opening" of the present disclosure. The first part 471 is an example of the "first end part" of the present disclosure. The fifth part 475 is an example of the "second end part" of the present disclosure.

[0046] FIG. 5 shows a state where the converter 407 is removed from the body 10 and placed on the ground. As shown in FIG. 5, the virtual lines L3 and L4 are lines parallel to the ground R. The virtual line L3 passes through the center of the front opening 4071. The virtual line L4 passes through the center of the rear opening 4072.

[0047] In this example, the virtual line L3 is at a position higher by a height h1 than the virtual line L4. Preferably, the height h1 is 20 mm or more and 40 mm or less. More preferably, the height h1 is 30 mm. In a state where the exhaust gas purification device 40 is removed from the body 10, unlike the attached state, the position of the lower end P1 of the opening 4071 is higher by a height h2 than the position of the lower end P2 of the opening 4072.

[0048] FIG. 6 is a diagram showing the state of the exhaust gas purification device 40 when the vehicle 1 is stopped or moving at a constant speed. As shown in FIG. 6, the exhaust gas and the vaporized urea are cooled to become a liquid W after the engine 20 stops and accumulate at the bottom of the converter 407. In this example, a part of the selective reduction catalyst 479 is immersed in the liquid W.

[0049] The height of the liquid level of the liquid W is lower than the lower end P1 of the opening 4071 (see FIG. 4). Specifically, when the vehicle 1 is stopped or moving at a constant speed, the shape of the converter 407 (for example, the position of the opening 4071) and the inclination angle θ are determined in advance in consideration of the volume of the liquid W generated so that the height of the liquid level of the liquid W becomes lower than the lower end P1 of the opening 4071. Thus, in the state of FIG. 6, since the height of the liquid level of the liquid W is lower than the lower end P1 of the opening 4071, the liquid is contained within the converter 407.

[0050] FIG. 7 is a transition diagram from the state of FIG. 6 and shows the state of the exhaust gas purification device 40 when the vehicle 1 decelerates. As shown in FIG. 7, when the vehicle 1 decelerates, due to inertia, the liquid W moves forward in the vehicle 1.

[0051] Specifically, the liquid W first reaches the mixer 409. After that, the liquid W passes through the mixer 409. Further, the liquid W reaches the tip of the injector 405. Thus, the liquid W reaches the injector 405 via the mixer 409 due to the deceleration of the vehicle.

[0052] As described above, the urea deposit is water-soluble. Therefore, the urea deposit 900 deposited near the tip portions of the mixer 409 and the injector 405 dissolves in the liquid W. After that, the liquid W in which the urea deposit 900 has dissolved evaporates (vaporizes) due to the heat of the exhaust gas. Further, the gas generated by the vaporization of the liquid W reacts with the selective reduction catalyst and is discharged to the outside of the vehicle 1 via the pipe 208 and the muffler 50.

[0053] As described above, more urea deposits 900 are deposited on the lower side than on the upper side of the mixer 409. The liquid W flows more on the lower side than on the upper side of the mixer 409. Therefore, the urea deposit 900 deposited on the mixer 409 can be efficiently removed by the liquid W.

[0054] In addition, when the degree of deceleration (acceleration) is equal to or greater than a predetermined value, the shape of the converter 407 (for example, the position of the opening 4071) and the inclination angle θ may be determined so that the liquid W reaches the injector 405 via the mixer 409.

[0055] <Parentheses> The exhaust gas purification device 40 is as follows in parentheses.

[0056] (1) The exhaust gas purification device 40 purifies the exhaust gas discharged from the engine 20 of the vehicle 1 traveling on the ground R. The exhaust gas purification device 40 includes (i) an injector 405 that injects the aqueous urea U into the exhaust gas discharge path V, (ii) a mixer 409 that is provided in the exhaust gas discharge path V in a state facing the injector 405 and mixes the injected aqueous urea U with the exhaust gas, and (iii) a converter 407 that is provided downstream of the mixer 409 in the exhaust gas discharge path V and reduces and purifies nitrogen oxides in the exhaust gas using ammonia generated by the above mixing.

[0057] In the attached state where the exhaust gas purification device 40 is attached to the vehicle body 10 of the vehicle 1, the mixer 409 is located behind the vehicle 1 with respect to the injector 405 and in front of the vehicle 1 with respect to the converter 407. The converter 407 extends from the front to the rear of the vehicle 1 in the above attachment state. The converter 407 is inclined so that the height from the ground R on the rear side of the vehicle 1 is higher than the height from the ground R on the front side of the vehicle 1 in the above attachment state, so that the liquid W accumulated at the bottom of the converter 407 due to liquefaction reaches the injector 405 via the mixer 409 due to the deceleration of the vehicle 1.

[0058] According to such a configuration, the deposit of urea accumulated on the injector 405 (specifically, near the tip of the injector 405) and the mixer 409 can be removed by the liquid W generated in the converter 409.

[0059] (2) The inclination angle of the converter 407 in the above-mentioned mounted state is 5 degrees or more and 10 degrees or less. According to such a configuration, when the vehicle 1 decelerates, the liquid W accumulated on the bottom surface of the converter 407 can reach the injector 405 via the mixer 409.

[0060] (3) In the above-mentioned mounted state, the exhaust gas in which nitrogen oxides are reduced and purified by the converter 407 is discharged from the muffler 50 of the vehicle 1 to the outside of the vehicle 1. The number of converters 407 between the mixer 409 and the muffler 50 is one.

[0061] For example, when a plurality (for example, two) of converters whose total capacity of each converter is the same as the capacity of the converter 407 and whose length in the front-rear direction of the vehicle 1 is shorter than that of the converter 407 are connected in the front-rear direction of the vehicle 1, if the height of the connection position is high, when the vehicle 1 decelerates, the same amount of liquid W as that of the converter 407 cannot be poured into the mixer 409 side.

[0062] However, in the exhaust gas purification device 40, since there is only one converter 407, according to the exhaust gas purification device 40, more liquid W can be supplied to the vicinity of the tip of the mixer 409 and the injector 405 compared to a configuration in which a plurality of converters are connected.

[0063] (4) As shown in FIG. 4, the converter 407 has a first part 471 that is the end on the mixer 409 side and a fifth part 475 that is the end on the rear side of the vehicle 1 with respect to the first part 471 in the above-mentioned mounted state. The exhaust gas purification device 40 further includes a pipe 206 in which the mixer 409 is accommodated and a pipe 208 connected to a second part 472 of the converter 407. An opening 4071 for communicating with the pipe 206 is formed in the first part 471. An opening 4072 for communicating with the pipe 208 is formed at the end of the fifth part 475. In the above-mentioned mounted state, the position of the lower end P1 of the opening 4071 is lower than the position of the lower end P2 of the opening 4072.

[0064] According to such a configuration, compared with the case where the position of the lower end P1 of the opening 4071 is higher than the position of the lower end P2 of the opening 4072, it becomes easier to supply the liquid W to the vicinity of the tip portions of the mixer 409 and the injector 405. Further, when the vehicle 1 is accelerating, it is possible to prevent the liquid W from flowing from the opening 4072 side into the pipe 408 side.

[0065] (5) The position of the opening 4071 in the converter 407 and the angle θ of inclination of the converter 407 in the above mounting state are set such that when the vehicle 1 stops, the liquid level height of the liquid W becomes lower than the lower end P1 of the opening 4071.

[0066] According to such a configuration, it is possible to prevent the bottom of the pipe 206 from being immersed in the liquid W when the vehicle 1 stops or the like.

[0067] <Supplementary Note> [Item 1] An exhaust gas purification device for purifying exhaust gas discharged from an internal combustion engine of a vehicle traveling on the ground, an injector for injecting aqueous urea into the exhaust gas discharge path of the exhaust gas, a mixer provided in the exhaust gas discharge path in a state facing the injector, for mixing the injected aqueous urea with the exhaust gas, a converter provided downstream of the mixer in the exhaust gas discharge path, for reducing and purifying nitrogen oxides in the exhaust gas using ammonia generated by the mixing, and the mixer is located behind the vehicle with respect to the injector and in front of the vehicle with respect to the converter in a mounting state where the exhaust gas purification device is mounted on the vehicle body, the converter is extending from the front to the rear of the vehicle in the mounting state, an exhaust gas purification device that is inclined in the mounting state such that the height from the ground on the rear side of the vehicle is higher than the height from the ground on the front side of the vehicle so that the liquid accumulated at the bottom of the converter due to liquefaction reaches the injector via the mixer due to the deceleration of the vehicle.

[0068] [Item 2] The exhaust gas purification device according to item 1, wherein an angle of the inclination in the mounted state is 5 degrees or more and 10 degrees or less.

[0069] [Item 3] In the mounted state, the exhaust gas in which nitrogen oxides are reduced and purified by the converter is discharged from a muffler of the vehicle to the outside of the vehicle. The exhaust gas purification device according to item 1 or 2, wherein the number of the converters between the mixer and the muffler is one.

[0070] [Item 4] The converter has a first end on the mixer side and a second end on the rear side of the vehicle relative to the first end in the mounted state. The exhaust gas purification device further includes a first pipe in which the mixer is accommodated, and a second pipe connected to the second end of the converter. A first opening for communicating with the first pipe is formed at the first end. A second opening for communicating with the second pipe is formed at the second end. The exhaust gas purification device according to any one of items 1 to 3, wherein a lower end of the first opening is lower than a lower end of the second opening in the mounted state.

[0071] [Item 5] The exhaust gas purification device according to item 4, wherein a position of the first opening in the converter and an angle of the inclination in the mounted state are set such that a liquid level height is lower than a lower end of the first opening when the vehicle stops.

[0072] [Item 6] A vehicle traveling on the ground, including an internal combustion engine, and an exhaust gas purification device that purifies exhaust gas discharged from the internal combustion engine. The exhaust gas purification device is an injector that injects aqueous urea into an exhaust gas discharge path through which exhaust gas discharged from the internal combustion engine passes, a mixer provided in the discharge path that mixes the injected aqueous urea with the exhaust gas, and a converter provided downstream of the mixer in the discharge path that reduces and purifies nitrogen oxides in the exhaust gas using ammonia generated by the mixing, wherein the mixer is located rearward of the vehicle relative to the injector and forward of the vehicle relative to the converter, and the converter extends from the front to the rear of the vehicle in an attached state where the exhaust gas purification device is attached to the vehicle body, and the vehicle is inclined such that in the attached state, a height from the ground on the rear side of the vehicle is higher than a height from the ground on the front side of the vehicle so that liquid accumulated at the bottom of the converter due to liquefaction reaches the mixer when the vehicle decelerates.

[0073] It should be considered that all aspects of the embodiments disclosed this time are illustrative and not restrictive. The scope of the present invention is indicated by the scope of claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

Explanation of Reference Numerals

[0074] 1 Vehicle, 10 Body, 20 Engine, 31 Front Wheel, 32 Rear Wheel, 40 Exhaust Gas Purification Device, 50 Muffler, 206, 208, 403, 404, 406, 408 Pipes, 401 Tank, 402 Pump, 405 Injector, 407 Converter, 409 Mixer, 451, 4071, 4072 Openings, 461, 471 First Parts, 462, 472 Second Parts, 463, 473 Third Parts, 470 Housing, 474 Fourth Part, 475 Fifth Part, 479 Selective Reduction Catalyst, 900 Urea Deposit, J1, J2, J3 Central Axes, L1, L2, L3, L4 Virtual Lines, P1, P2 Lower Ends, R Ground, U Aqueous Urea, V Exhaust Gas Discharge Path, W Liquid.

Claims

1. An exhaust gas purification device for purifying exhaust gas discharged from an internal combustion engine of a vehicle traveling on the ground, comprising: an injector for injecting aqueous urea into an exhaust gas discharge path of the exhaust gas; a mixer provided in the discharge path facing the injector for mixing the injected aqueous urea with the exhaust gas; a converter provided downstream of the mixer in the discharge path for reducing and purifying nitrogen oxides in the exhaust gas using ammonia generated by the mixing; in the attached state where the exhaust gas purification device is attached to the vehicle body, the mixer is located behind the injector and in front of the converter with respect to the vehicle; the converter: extends from the front to the rear of the vehicle in the attached state; An exhaust gas purification device that is inclined such that in the attached state, the height from the ground on the rear side of the vehicle is higher than the height from the ground on the front side of the vehicle so that the liquid accumulated at the bottom of the converter due to liquefaction reaches the injector via the mixer when the vehicle decelerates.

2. The exhaust gas purification device according to claim 1, wherein an angle of the inclination in the attached state is 5 degrees or more and 10 degrees or less.

3. In the attached state, the exhaust gas in which the nitrogen oxides are reduced and purified by the converter is discharged from the muffler of the vehicle to the outside of the vehicle, The exhaust gas purification device according to claim 1, wherein the number of converters between the mixer and the muffler is one.

4. The converter has a first end on the mixer side and a second end on the rear side of the vehicle with respect to the first end in the attached state, The exhaust gas purification device further comprises: a first pipe housing the mixer; a second pipe connected to the second end of the converter; a first opening for communicating with the first pipe is formed at the first end; a second opening for communicating with the second pipe is formed at the second end; The exhaust gas purification device according to claim 1, wherein a lower end of the first opening is lower than a lower end of the second opening in the attached state.

5. The exhaust gas purification device according to claim 4, wherein the position of the first opening in the converter and the angle of the inclination in the mounting state are set such that the liquid level height is lower than the lower end of the first opening when the vehicle stops.

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