KR20220003253A - NOx Reduction Device - Google Patents

Abstract

The present invention relates to an apparatus for reducing NOx using an LNT, an SDPF, and urea water spraying. According to the present invention, an exhaust gas discharged from the LNT through a blocker cannot be bypassed to an SDPF side, and a urea water is sprayed while flow of the exhaust gas is changed to a urea water injector side. Therefore, it is possible to achieve an effect of improving ammonia uniformity in the exhaust gas. In addition, an effect of improving mixing performance of the exhaust gas and the urea water through a vortex generating means formed in a lower part of the blocker is achieved. It is possible to achieve an effect that the exhaust gas is collected at the center of an SDPF inlet before the exhaust gas is discharged to the SDPF. The NOx reduction apparatus of the present invention comprises: the LNT; the SDPF; a communication unit; a urea water injector; the blocker; and the vortex generating means.

Description

NOx Reduction Device {NOx Reduction Device}

The present invention relates to an apparatus for reducing NOx using LNT, SDPF and urea water injection.

In general, the exhaust gas discharged from the engine is guided to a catalytic converter disposed in the middle of the exhaust pipe to be purified, and after passing through a muffler, noise is attenuated, and then discharged to the atmosphere through the tail exhaust pipe.

In a diesel engine, a filtration device is a device for treating pollutants contained in exhaust gas, and a catalyst carrier for collecting particulate matter (PM) contained in the exhaust gas is disposed therein to remove various exhaust gases discharged from the engine. It is purified through a chemical transformation process.

As a filtration device that performs the same role as above, DPF (Diesel Particulate Filter) with a built-in multi-pore filter to filter particulate matter in exhaust gas, LNT (Lean NOx Trap) with a built-in noble metal catalyst to adsorb NOx, and ammonia SCR (Selective Catalytic Reduction) that reacts NOx and ammonia with nitrogen and water using a reducing agent, NH3 and exhaust gas supplied from the front end of SDPF by coating SCR catalyst (generally Cu-zeolite, Fe-zeolite) on the multi-pore DPF There is a Selective Diesel Particulate Filter (SDPF) that purifies NOx into water and N2 by reacting NOx in the SCR catalyst.

Such filtration devices have characteristics for each type, so it is difficult to configure a plurality of filtration devices into one system. For example, when LNT and SDPF are simply combined, when post-injection is performed to deNOx the NOx captured in LNT, ammonia is generated as a by-product, so NOx reduction of SDPF is possible. There is a disadvantage in that there is a limit to the improvement of exhaust gas purification performance because it cannot reduce NOx.

In addition, when purifying NOx by spraying urea water to the SDPF, urea water particles and exhaust gas must be evenly mixed in order to increase the NOx purification efficiency, but there is a disadvantage in that it is difficult to evenly mix urea water particles and exhaust gas.

In addition, in order to evenly mix the urea water particles and exhaust gas, the spray uniformity of the urea water particles must be improved. Until now, the flow path is formed to be long by simply spraying the urea water in a spray method and zigzag the flow path. There is a need for a method to solve this problem because only a method has been suggested, but a device for uniformly mixing the number of urea in the exhaust gas and improving the uniformity of the flow has not been proposed.

The matters described as the background art above are only for improving the understanding of the background of the present invention, and should not be accepted as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art.

KR 10-0999615

The present invention is proposed to solve the above problem, and by installing a blocker inside the mixing unit for mixing urea water, the exhaust gas is prevented from bypassing when it moves to the SDPF side, and the exhaust gas is branched through the vortex generating means and at the same time An object of the present invention is to provide a novel type of NOx reduction device that generates a vortex to improve the uniformity of exhaust gas and ammonia and the uniformity of exhaust gas flow.

According to at least one embodiment of the present invention, LNT; SDPF; a communication part comprising an LNT connection part connected to the LNT, an SDPF connection part connected to the SDPF, and an intermediate part connecting between the LNT connection part and the SDPF connection part, and communicating the exhaust gas of the LNT to the SDPF; a urea water injector installed in the LNT connection part and injecting urea water from one side inside the LNT connection part; a blocker provided in the LNT connection part to pass through the middle part while blocking a part of the exhaust gas; and a vortex generating means provided on the downstream side of the blocker in the communication part, wherein the blocker blocks at least a portion of the exhaust gas flowing from the LNT while guiding it toward the urea water injector; There is provided a NOx reduction device connected to the first blocking portion and having a second blocking portion provided to face the flow toward the middle portion of the exhaust gas bypassing the first blocking portion and passing through the exhaust gas while blocking the exhaust gas.

In at least one embodiment of the present invention, the first blocking portion has a semicircular shape, is connected to the inner circumferential surface of the LNT connection part on the circumferential circumferential surface, and the second blocking portion is the first blocking portion in the semicircular straight portion It is connected at a predetermined angle to and extends to the inner surface of the LNT connection part.

In at least one embodiment of the present invention, the second blocking portion includes a concave portion concavely formed toward the SDPF connection portion in the center.

In at least one embodiment of the present invention, the first blocking portion is formed with a plurality of first through-holes.

In at least one embodiment of the present invention, the vortex generating means includes: a first vortex generating unit disposed in the middle portion; and a second vortex generator disposed on the SDPF connection part.

In at least one embodiment of the present invention, the vortex generating means includes: a branch plate having one side coupled to the first blocking portion; a first wing portion protruding from both sides of the branch plate and disposed in the middle portion; It includes a second wing portion which is split to both sides from the other side of the branch plate and is formed to extend into the SDPF connection portion.

In at least one embodiment of the present invention, each wing of the second wing portion is formed to be curved along the shape of the inner circumferential surface while maintaining a distance from the SDPF connecting portion inner circumferential surface.

In at least one embodiment of the present invention, a blocking film for preventing the flow of the exhaust gas flowing in from the middle part from directly flowing into the SDPF is included at the SDPF side edge of the second wing part.

In at least one embodiment of the present invention, the communication unit communicates with the SDPF by bending the exhaust gas flow direction from the LNT at least twice.

In at least one embodiment of the present invention, the urea water injector is arranged to inject the urea water in a direction from the LNT connection part toward the SDPF connection part.

According to the NOx reduction device having the structure as described above, the exhaust gas discharged from the LNT through the blocker is prevented from bypassing the SDPF side, and the urea water is injected in a state in which the flow of the exhaust gas is changed in the urea water injector side. By doing so, the effect of improving the ammonia uniformity in the exhaust gas can be achieved.

In addition, the effect of improving the mixing performance of exhaust gas and urea water is achieved through the vortex generating means formed at the bottom of the blocker, and the effect of collecting the exhaust gas to the center of the SDPF inlet before it is discharged to the SDPF can be achieved. can

1 is a view showing an apparatus for reducing NOx according to an embodiment of the present invention.
2 is a view showing a state in which the communication part is disassembled in the NOx reduction device according to the embodiment of the present invention.
3 is a view showing the state of injection of urea water and the exhaust gas flow in the NOx reduction device according to an embodiment of the present invention.
4 is a side view illustrating a state in which the communication unit housing is separated from the NOx reduction device according to an embodiment of the present invention.
5 is a view showing a communication part of the NOx reduction device according to an embodiment of the present invention.
6 is a view showing a blocker and a vortex generating means of the NOx reduction device according to an embodiment of the present invention.
7 is a view showing a vortex generating means according to another embodiment of the present invention.
8 is a view showing a blocking film formed on the second wing portion in the vortex generating means of FIG.

Hereinafter, an apparatus for reducing NOx according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

The NOx reduction device according to the present invention includes an LNT 100 , an SDPF 110 , a communication unit 160 , a urea water injector 220 , a blocker 230 , and a vortex generating means 285 .

The LNT 100 is a device for reducing the filter by re-burning the NOx accumulated in the filter by tying it to the filter without releasing some of the NOx, and then releasing the fuel in excess.

SDPF 110 is a compound word of SCR device and DPF, and since SDPF 110 is obvious to those skilled in the art, detailed description thereof will be omitted. In this embodiment, the LNT 100 and the SDPF 110 are provided in a cylindrical shape and are arranged in parallel as shown in FIG. 1 .

The LNT 100 and the SDPF 110 are installed in the LNT housing 120 and the SDPF housing 130 , and an exhaust gas inlet 140 is formed at one side of the LNT housing 120 . In addition, an exhaust gas outlet 150 is formed at one side of the SDPF housing 130 . The LNT housing 120 and the SDPF housing 130 are fixed with a bracket 320 .

The communication part 160 includes a communication part housing 180 and a communication part cover 170 as shown in FIG. 2 .

Referring to FIG. 5 , the communication unit housing 180 is divided into an LNT connection unit 190 , an SDPF connection unit 200 and an intermediate part 210 , and the LNT connection unit 190 is connected to the other side of the LNT housing 120 . . In addition, the SDPF connection part 200 is connected to the other side of the SDPF housing 130 . The middle part 210 connects between the LNT connection part 190 and the SDPF connection part 200 .

The communication part cover 170 is provided with the LNT hole 171 and the SDPF hole 172 to which the LNT housing 120 and the SDPF housing 130 are coupled, and is installed in the communication part housing 180 .

The communication unit 160 may communicate with the SDPF 110 by bending the exhaust gas flow direction from the LNT 100 at least twice. In this embodiment, as shown in Fig. 1, the flow direction is bent once from the A direction to the B direction, and the NOx reduction device is bent twice from the B direction to the C direction to form a U shape.

The urea water injector 220 is installed in the LNT connection part 190 to inject the urea water to one side inside the LNT connection part 190 . The urea water injector 220 is arranged to inject the urea water in the B direction, which is the direction from the LNT connection part 190 side toward the SDPF connection part 200 . In this embodiment, the urea water injector 220 may be installed so that the urea water is injected in the B direction.

The blocker 230 is provided on the communication part cover 170 and passes through the middle part 210 while blocking a part of the exhaust gas. The blocker 230 includes a first blocking unit 240 and a second blocking unit 250 . The first blocking unit 240 guides the exhaust gas toward the urea water injector 220 while blocking at least a portion of the exhaust gas flowing from the LNT 100 as shown in FIG. 4 .

The first blocking part 240 has a semicircular shape as shown in FIGS. 6 (a) and (b). A plurality of first through-holes 260 are formed in the first blocking portion 240 . The first through hole 260 is configured in plurality in the circumferential direction, and a part of the exhaust gas is bypassed to the SDPF 110 so that the exhaust gas coming out of the LNT 100 by the first blocking part 240 is discharged. It is possible to achieve the effect of preventing the direct bypass to the SDPF (110).

The first through-holes 260 are disposed to be spaced apart from each other on both sides except for the central portion of the first blocking portion 240 as shown in FIG. 3 . In addition, preferably, the first through-holes 260 formed on both sides as described above are formed to be spaced apart from each other on both sides more than the minimum width, which is the central portion width of the intermediate portion 210 .

The first blocking part 240 is the exhaust gas discharge direction so that the exhaust gas discharged from the LNT 100 changes the flow (see arrow) near the urea injector 220 as shown in FIG. formed concave in the direction For detailed shapes, refer to FIGS. 6(a) and 6(b).

The second blocking part 250 is connected to the first blocking part 240 and is provided to face the flow toward the middle part 210 of the exhaust gas bypassing the first blocking part 240 to block the exhaust gas. penetrate

The second blocking portion 250 is bent from the semicircular straight portion of the first blocking portion 240 to extend and connect to the inner wall surface of the LNT connection portion 190 . The second blocking portion 250 includes a concave portion 280 bent at the center and concavely formed toward the SDPF connection portion 200 . The concave portion 280 can achieve the effect of increasing the uniformity of ammonia in the exhaust gas so as to spread with the exhaust gas to the radially outer side of the concave portion 280 when the urea water is injected, as shown in FIG. 3 .

A plurality of second through-holes 270 are formed in the second blocking unit 250 to change the flow of exhaust gas in several directions to allow ammonia to be uniformly mixed with the exhaust gas. The first blocking portion 240 , the second blocking portion 250 , and the concave portion 280 may be integrally formed.

The vortex generating means 285 is provided on the downstream side of the blocker 230 in the communication unit 160 .

The vortex generating means 285 is formed in the branch plate 290 and the branch plate 290 that branch the flow direction of the exhaust gas into two branches as shown in FIG. 3, the middle part 210 of the communicating part 160 ) and a second vortex generator disposed at the SDPF connection unit 200 of the communicating unit 160 and a first vortex generating unit disposed in the .

The first vortex generating unit and the second external current generating unit refer to a first wing unit 300 and a second wing unit 310 to be described later.

The branch plate 290 has one side welded to the downstream outer surface of the first blocking part 240 , the first wing part is formed to protrude outward from both sides of the branch plate 290 and disposed in the middle part 210 . (300). In addition, the branch plate 290 includes a second wing portion 310 that is split from the other side to both sides and extended to the inside of the SDPF connection portion 200 .

The first wing part 300 may be formed smaller than the second wing part 310 . The first wing part 300 is the middle part of the communication part 160 having a small width as shown in FIGS. 3 and 5 . It is possible to achieve the effect of increasing the uniformity of ammonia while the urea water located at 210 and sprayed to the middle part 210 is mixed by the vortex generated by the first wing part 300 .

The second wing part 310, which has a larger shape than the first wing part 300, is in an inverted Y-shape that is split on both sides, and flows into the SDPF connection part 200 side of the communication part 160 as shown in FIG. 3 . It serves to branch the exhaust gas to both sides.

Each blade of the second wing part 310 is formed to be curved along the shape of the inner peripheral surface while maintaining a distance from the inner peripheral surface of the SDPF connection part. The branched exhaust gas moves along the inner peripheral surface of the SDPF connection part of the communication part housing 180 and flows into the inside of the second wing part 310 to generate a vortex. Through this, the second wing unit 310 may achieve the effect of collecting the exhaust gas to the center of the SDPF connection unit 200 . Before the exhaust gas flows into the SDPF 110 , it is possible to achieve the effect of facilitating the collection of fine dust in the SDPF 110 by collecting it in the center of the SDPF connection part 200 .

In another embodiment, a blocking film 311 may be additionally formed on the second wing unit 310 as shown in FIG. 7 . The blocking film 311 is formed by bending a portion of the second wing part 310 as shown in FIG. 8 , and the blocking film 311 is advantageous for vortex generation of exhaust gas, and the exhaust gas mixed with urea water is SDPF (110) It is possible to achieve the effect of preventing the bypass directly.

The branch plate 290, the first wing part 300 and the second wing part 310 are formed to extend from the communicating part cover 170 to the inner wall of the communicating part housing 180 so that the vortex of the exhaust gas is well generated. .

Although the present invention has been shown and described with respect to specific embodiments, it is within the art that the present invention can be variously improved and changed without departing from the spirit of the present invention provided by the following claims. It will be obvious to those of ordinary skill in the art.

100: LNT
110: SDPF
120: LNT housing
130: SDPF housing
140: exhaust gas inlet
150: exhaust gas outlet
160: communication unit
170: communication part cover
171: LNT Hall
172: SDPF hole
180: communication unit housing
190: LNT connection
200: SDPF connection
210: middle part
220: urea water injector
230: blocker
240: first blocking unit
250: second blocking unit
260: first through hole
270: second through hole
280: recess
285: vortex generating means
290: branch plate
300: first wing portion (first vortex generating portion)
310: second wing portion (second vortex generating portion)
311: barrier
320: bracket

Claims (10)

LNT;
SDPF;
a communication part including an LNT connection part connected to the LNT, an SDPF connection part connected to the SDPF, and an intermediate part connecting between the LNT connection part and the SDPF connection part, and communicating the exhaust gas of the LNT to the SDPF;
a urea water injector installed in the LNT connection part and injecting urea water from one side inside the LNT connection part;
a blocker provided in the LNT connection part to pass through the middle part while blocking a part of the exhaust gas; and
and a vortex generating means provided on the downstream side of the blocker in the communication part,
The blocker is
a first blocking part leading to the urea water injector while blocking at least a portion of the exhaust gas flowing from the LNT;
It is connected to the first blocking portion and is provided opposite to the flow toward the middle portion of the exhaust gas bypassing the first blocking portion and includes a second blocking portion that passes through while blocking the exhaust gas,
NOx reduction device, characterized in that. According to claim 1,
The first blocking portion has a semicircular shape, and is connected to the inner peripheral surface of the LNT connection part on the circumferential circumferential surface,
NOx reduction device, characterized in that the second blocking portion is connected to the first blocking portion at a predetermined angle in the semicircular straight portion and extends to the inner surface of the LNT connection portion. According to claim 1,
The second blocking portion NOx reduction device, characterized in that it comprises a concave portion formed concave toward the SDPF connection portion in the center. According to claim 1,
NOx reduction device, characterized in that the first blocking portion is formed with a plurality of first through-holes. According to claim 1,
The vortex generating means includes:
a first vortex generator disposed in the middle portion; and
A second vortex generator disposed on the SDPF connection part
NOx reduction device comprising a. According to claim 1,
The vortex generating means includes:
a branch plate having one side coupled to the first blocking part;
a first wing portion protruding from both sides of the branch plate and disposed in the middle portion;
A second wing part split from the other side of the branch plate to both sides and formed to extend into the SDPF connection part
NOx reduction device comprising a. 7. The method of claim 6,
NOx reduction device, characterized in that each blade of the second wing portion is formed to be curved along the shape of the inner circumferential surface while maintaining a distance from the SDPF connecting portion inner circumferential surface. 7. The method of claim 6,
NOx reduction device, characterized in that it comprises a blocking film to prevent the flow of the exhaust gas flowing in from the middle portion directly flowing into the SDPF at the SDPF side edge of the second wing portion. According to claim 1,
NOx reduction device, characterized in that the communication unit bends the flow direction of the exhaust gas from the LNT at least twice to communicate with the SDPF. According to claim 1,
The urea water injector is a NOx reduction device, characterized in that it is arranged to inject the urea water in a direction from the LNT connection part toward the SDPF connection part.

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