JP6992216B2 - Mixer for exhaust gas aftertreatment system, exhaust gas aftertreatment system, and internal combustion engine - Google Patents

Description

The present invention relates to a mixing device for an exhaust gas aftertreatment system, an exhaust gas aftertreatment system for an internal combustion engine, and an internal combustion engine having an exhaust gas aftertreatment system.

Combustion processes in fixed internal combustion engines, such as those used in power plants, and combustion processes in non-fixed internal combustion engines, such as those used in ships, generate nitrogen oxides, which are these nitrogen oxides. It occurs upon combustion of fossil fuels, typically containing sulfur such as coal, bitumen, lignite, petroleum, heavy oil, or diesel fuels. Therefore, such an internal combustion engine is provided with an exhaust gas aftertreatment system used for purifying the exhaust gas discharged from the internal combustion engine, particularly denitrification.

In order to reduce nitrogen oxides in exhaust gas, so-called SCR catalytic converters are first used in exhaust gas aftertreatment systems known in practice. In the SCR catalytic converter, selective catalytic reduction of nitrogen oxides is performed, and ammonia (NH ₃ ) is required as a reducing agent for the reduction of nitrogen oxides. For this purpose, the ammonia precursor such as urea or carbamide is introduced into the exhaust gas in the form of a liquid upstream of the SCR catalytic converter, and the ammonia precursor is mixed with the exhaust gas and decomposed upstream of the SCR catalytic converter. Produces a reducing agent. For this purpose, in practice, a mixing and decomposition section is provided between the ammonia precursor introduction device and the SCR catalytic converter.

Exhaust gas post-treatment, especially the reduction of nitrogen oxides, can already be successfully carried out using a practice-known exhaust gas after-treatment system, including an SCR catalytic converter, but the exhaust gas after-treatment system needs to be further improved. There is sex. In particular, when the structure is miniaturized, it is necessary to enable low-noise exhaust gas post-treatment.

Based on this need, the subject of the present invention is a new mixing device for an exhaust gas aftertreatment system that enables low noise exhaust gas aftertreatment when the structure is miniaturized. The purpose is to create an exhaust gas aftertreatment system and an internal combustion engine having an exhaust gas aftertreatment system.

This problem is solved by the mixing device according to claim 1. According to the present invention, the exhaust gas supply conduit is provided with a silencer in the region of the mixing and decomposition section. The miniaturized structure enables low-noise exhaust gas post-treatment.

Preferably, the portion of the exhaust gas supply conduit and the silencer constituting the mixing and decomposition section, or the exhaust gas supply conduit and the silencer are integrated into a common assembly. Especially in a miniaturized structure, low noise exhaust gas post-treatment becomes possible.

According to a favorable further development, the silencer has a plurality of silencer chambers, each of which is connected to an exhaust gas supply conduit through at least one opening. The miniaturized structure enables low-noise exhaust gas post-treatment.

According to another advantageous further development, the silencer's first silencer chamber is through at least one first opening and / or the silencer's second silencer chamber is at least one second. Connected to the exhaust gas supply conduit through the opening, the distance of one or each opening located upstream of the introduction device is up to 3 times the diameter of the exhaust gas supply conduit in the area of the introduction device. The distance of one or each opening located downstream of the introduction device is at most 1 time, or at least 2 times, the diameter of the exhaust gas supply conduit in the area of the introduction device. In the area of the mixing and decomposition section, the distance from the introduction device corresponds to between 1 times the diameter of the exhaust gas supply conduit in the area of the introduction device and 2 times the diameter of the exhaust gas supply conduit in the area of the introduction device. In the area, there is no opening such as connecting the muffler's muffling chamber to the exhaust gas supply conduit. The miniaturized structure enables low-noise exhaust gas post-treatment. In particular, it prevents liquid reducing agent precursors, such as urea, from reaching the region of the opening connecting the silencer chamber to the exhaust gas supply conduit and clogging or blocking the opening.

Preferably, the silencer's third silencer chamber is connected upstream of the introduction device to the exhaust gas supply conduit through at least one third opening. The miniaturized structure enables low-noise exhaust gas post-treatment. The distance from the introduction device at the end of the mixing and decomposition section is advantageously between 2 and 6 times the diameter of the exhaust gas conduit in the area of the introduction device.

The exhaust gas aftertreatment system according to the present invention is defined in claim 11.

The internal combustion engine according to the present invention is defined in claim 14.

Preferred further developments of the invention will be apparent from the sub-claims and the following description. The embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. The figure below is shown.

It is a schematic perspective view of the internal combustion engine which has the exhaust gas aftertreatment system which concerns on this invention. It is a figure which shows the detail of the exhaust gas aftertreatment system which concerns on FIG. 1 in the area of the mixing apparatus which concerns on this invention.

The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine such as a fixed internal combustion engine of a power plant or a non-fixed internal combustion engine used in a ship.

In particular, the present invention relates to an SCR exhaust gas aftertreatment system for a marine diesel internal combustion engine operated by heavy oil or residual oil, preferably configured as a two-stroke marine diesel internal combustion engine.

FIG. 1 shows the arrangement of an internal combustion engine 1 having an exhaust gas supercharging system 2 and an exhaust gas aftertreatment system 3.

The internal combustion engine 1 may be an unfixed or fixed internal combustion engine, particularly a marine internal combustion engine that is operated without fixing. The exhaust gas discharged from the cylinder 4 of the internal combustion engine 1 is used in the exhaust gas supercharging system 2 to obtain mechanical energy for compressing the supercharged air to be supplied to the internal combustion engine 1 from the thermal energy of the exhaust gas. Be done.

FIG. 1 shows an internal combustion engine 1 having an exhaust gas supercharging system 2, which includes at least one exhaust gas turbocharger 5. The exhaust gas discharged from the cylinder 4 of the internal combustion engine 1 flows through the turbine 6 of the exhaust gas turbocharger 5, expands in the turbine, and the energy obtained at that time is used to compress the supercharged air. It is used in the compressor (not shown) of the exhaust gas turbocharger 5. The internal combustion engine 1 may have a two-stage exhaust gas supercharging system 2 including a high pressure turbocharger and a low pressure turbocharger.

In addition to the exhaust gas supercharging system 2, the internal combustion engine 1 includes an SCR exhaust gas aftertreatment system. Since the exhaust gas aftertreatment system 3 is preferably connected between the cylinder 4 of the internal combustion engine 1 and the exhaust gas supercharging system 2, the exhaust gas discharged from the cylinder 4 of the internal combustion engine 1 is first exhaust gas aftertreatment system. It is guided to pass through the exhaust gas supercharging system 2 for the first time after passing through 3.

FIG. 1 shows an exhaust gas supply conduit 8, through which exhaust gas can be guided from the cylinder 4 of the internal combustion engine 1 toward the SCR catalytic converter 9 located in the reaction chamber 10. .. Further, FIG. 1 shows an exhaust gas discharge conduit 11, which is used to discharge exhaust gas from the SCR catalytic converter 9 toward the turbine 6 of the exhaust gas turbocharger 5.

The internal combustion engine 1 of FIG. 1 has an exhaust gas manifold 7 common to all cylinders 4. Exhaust gas discharged from the cylinder 4 of the internal combustion engine 1 can be guided from the exhaust gas manifold 7 through the exhaust gas supply conduit 8 toward the exhaust gas aftertreatment system 3, that is, each reaction chamber 10 and each SCR catalytic converter 9. Therefore, downstream of the exhaust gas aftertreatment system 3, it can be guided to pass through the exhaust gas turbocharger 5 of the exhaust gas supercharging system 2.

The exhaust gas supply conduit 8 extending to the reaction chamber 10 and thus the SCR catalytic converter 9 arranged inside the reaction chamber 10, and the exhaust gas discharge extending so as to be separated from the reaction chamber 10 and the SCR catalytic converter 9. The conduit 11, or the exhaust manifold 7 and the exhaust gas discharge conduit 11, are preferably connected via a bypass (not shown) containing a blocking element. When the blocking element is closed, the bypass is also closed and the exhaust gas cannot flow through the bypass. In contrast, when the blocking element is open, the exhaust gas passes through the bypass, i.e. the SCR located from the exhaust gas supply conduit 8 to the exhaust gas discharge conduit 11 and thus inside the reaction chamber 10 and thus the reaction chamber 10. It is possible to bypass the catalytic converter 9 and distribute it directly.

An introduction device 12 is arranged in the exhaust gas supply conduit 8 of the exhaust gas aftertreatment system 3, and a reducing agent precursor, that is, an ammonia precursor such as urea or carbamide can be introduced into the exhaust gas flow through the introduction device. .. The reducing agent precursor is mixed with the exhaust gas and decomposed to produce ammonia (NH ₃ ), which is the original reducing agent. The reducing agent is required in the region of the SCR catalytic converter 9 to convert the nitrogen oxides of the exhaust gas as predetermined. The introduction device 12 of the exhaust gas aftertreatment system 3 is preferably an injection nozzle, and the ammonia precursor is injected into the exhaust gas flow in the exhaust gas supply conduit 8 through the injection nozzle. In FIG. 2, the cone 13 shows the injection of the reducing agent precursor into the exhaust gas flow in the region of the exhaust gas supply conduit 8.

The section of the exhaust gas aftertreatment system 3 or the exhaust gas supply conduit 8 located downstream of the introduction device 12 and upstream of the SCR catalytic converter 9 in the direction of exhaust gas flow is referred to as a mixing and decomposition section 14. In particular, the exhaust gas supply conduit 8 is provided with a mixing and decomposition section 14 downstream of the introduction device 12, and in the mixing and decomposition section, the reducing agent precursor is decomposed to generate a reducing agent, and the exhaust gas is discharged. It can be mixed with the reducing agent upstream of the SCR catalytic converter 9.

The introduction device 12 and the exhaust gas supply conduit 8, that is, the portion of the exhaust gas supply conduit 8 that supplies the mixing and decomposition section 14 extending downstream of the introduction device 12, is an assembly of the mixing device of the exhaust gas aftertreatment system 3. The assembly is used to decompose the reducing agent precursor to produce a reducing agent and mix the reducing agent introduced into the exhaust gas through the introduction device 12 with the exhaust gas.

The exhaust gas supply conduit 8 is provided with a silencer 21 in the region of the mixing and disassembling section 14. Therefore, the mixing and disassembling section 14 and the silencer 21 are spatially integrated. Thereby, in a miniaturized structure, low noise exhaust gas post-treatment can be ensured. The silencer 21 preferably has a plurality of silencer chambers 22, 23 and 24. Each muffling chamber 22, 23 and 24 is connected to the exhaust gas supply conduit 8 through at least one opening 25, 26, 27, respectively.

According to FIG. 2, the first muffling chamber 22 is attached upstream of the introduction device 12 through at least one opening 25. The second silencer chamber 23 of the silencer 21 is connected to the exhaust gas supply conduit 8 through at least one other opening 26, downstream of the introduction device 12 in the region of the mixing and disassembling section 14. The distance X1 from the introduction device 12 of one or each first opening 26 corresponds to a maximum of 1 times the diameter d of the exhaust gas supply conduit 8 in the region of the introduction device 12.

Further, according to FIG. 2, the third silencer chamber 24 of the silencer 21 passes through at least one other opening 27, also downstream of the introduction device 12, in the region of the mixing and disassembling section 14, the exhaust gas supply conduit 8 Is linked to. The distance of one or each of the second openings 27 from the introduction device 12 corresponds to a minimum of twice the diameter d of the exhaust gas supply conduit 8 in the region of the introduction device 12.

In the region of the mixing and decomposition section 14, the distance from the introduction device 12 is 1 times the diameter d of the exhaust gas supply conduit 8 in the region of the introduction device 12 and the diameter d of the exhaust gas supply conduit 8 in the region of the introduction device 12. In the region corresponding to the double, an opening such as connecting the muffling chambers 23 and 24 of the muffler 21 to the exhaust gas supply conduit 8 is not formed. Therefore, in the downstream of the distance X1 and the upstream of the distance X2, an opening such as connecting the muffling chamber of the muffler 21 to the exhaust gas supply conduit 8 is not formed.

By positioning the openings 25, 26, 27 connecting the muffling chambers 22, 23, 24 of the muffler 21 to the exhaust gas supply conduit 8 described above, the liquid reducing agent precursor, that is, the liquid urea, is removed from the opening 25. It can be ensured that the regions 26, 27 are not reached and that these openings are not blocked.

Up to a distance X1, droplets of reducing agent precursor cannot reach the region of the first opening 26. At a distance of X2 at the latest, the reducing agent precursor, or urea, is decomposed into ammonia (NH ₃ ) and CO ₂ , so there is a risk that the liquid reducing agent precursor will clog the opening 27 downstream of the distance X2. Does not occur.

The silencer 21 is configured as a Helmholtz resonator and / or a λ / 4 resonator and / or a sound absorbing silencer. The sound absorbing type silencer is further filled with a sound absorbing material such as glass fiber or ceramic fiber.

Downstream of the introduction device 12, the muffling chambers 23, 24 connected to the exhaust gas supply conduit 8 in the region of the mixing and disassembling section 14 through the openings 26, 27 are configured as λ / 4 resonators. On the other hand, it can be specified that the muffling chamber 22 connected to the exhaust gas supply conduit 8 upstream of the introduction device 12 through the opening 25 is configured as a Helmholtz resonator. This is preferable, but not compulsory. It is also possible to configure all muffling chambers as λ / 4 resonators, Helmholtz resonators, or sound absorbing resonators. Further, downstream of the introduction device 12, in the region of the mixing and disassembling section 14, the muffling chambers 23, 24 connected to the exhaust gas supply conduit 8 can be configured as a Helmholtz resonator or as a sound absorbing silencer. , The muffling chamber 22 connected to the exhaust gas supply conduit 8 through the opening 25 upstream of the introduction device 12 may be configured as a λ / 4 resonator or as a sound absorbing silencer.

Further, it has been clarified that it is advantageous to provide the built-in materials (Einbauten) 18a and 18b in the exhaust gas supply conduit 8, and as a result of providing the built-in material, the cross section is rapidly increased, thereby further noise. It is possible to reduce radiation. The incorporation is, in the simplest case, a plate that can be arranged or configured in a planar embodiment (18a), but also in an angular aspect (18b), in addition that the plate is relative to the main flow direction. Can be aligned at various angles. The inclusion may be located upstream of the introduction device 12 and / or at a distance corresponding to at least twice the diameter d of the exhaust gas supply conduit 8 in the region of the introduction device 12.

The silencer 21 and the exhaust gas supply conduit 8, that is, in FIG. 2, at least the portion of the exhaust gas supply conduit 8 in which the silencer 21 is arranged, is preferably integrated into a common assembly and incorporated into the member. This is particularly advantageous for structural miniaturization.

Preferably, the exhaust manifold 7 is also integrated into a common assembly along with the mixing and disassembling section 14 or the exhaust gas supply conduit 8 and the silencer 21. At that time, according to the embodiment shown in FIG. 1, the exhaust gas discharge conduit 8 constituting the mixing and decomposition section 14 at least partially is coaxial with the downstream of the exhaust gas manifold 7 when viewed in the direction of the exhaust gas flow. It is stipulated that the exhaust gas can be supplied from the exhaust gas manifold 7 to the mixing and decomposition section 14 without changing the direction because of the arrangement.

In FIG. 1, the exhaust gas flows into the exhaust gas manifold 7 in the region of the exhaust gas opening position 16 on the cylinder side, and in the region of the downstream end portion 15 of the exhaust gas supply conduit 8 upstream of the SCR catalytic converter 9. Only when flowing into 10 will you experience a change of direction. This is advantageous for ensuring low noise exhaust gas aftertreatment.

1 and 2 are arrows 17 indicating the flow of exhaust gas. From FIG. 1, it can be seen that the exhaust gas 7 changes direction by about 90 ° or approximately 90 ° in the region of the exhaust gas opening position 16 on the cylinder side and flows into the exhaust gas manifold 7. The exhaust gas departs from the exhaust gas manifold 7 and flows through the exhaust gas supply conduit 8 without changing direction to the downstream end portion 15 of the exhaust gas supply conduit 8 which opens to the region of the reaction chamber 10. In the region of the end 15 of the exhaust gas supply conduit 8, the flow diverts about 180 ° or approximately 180 ° and the exhaust gas is guided through the SCR catalytic converter 9 after this diversion of the flow. To.

The exhaust gas supply conduit 8 is open to the reaction chamber 10 at the downstream end portion 15. According to a preferred embodiment, the exhaust gas supply conduit 8 widens in a funnel shape in the region of its downstream end 15 to form a diffuser 18. As a result, the flow cross section of the exhaust gas supply conduit 8 is expanded in the region of the downstream end portion 15, and when viewed in the direction of the exhaust gas flow, in the upstream of the diffuser 18 of the downstream end portion 15 of the exhaust gas supply conduit 8. It can be specified that the flow section is first reduced.

The exhaust gas supply conduit 8 and the exhaust gas discharge conduit 11 are connected by a common first surface 19 of the reaction chamber 10. At that time, the exhaust gas supply conduit 8 has a first surface so that the downstream end portion 15 thereof is located adjacent to the second surface 20 of the reaction chamber 10 facing the first surface 19 of the reaction chamber 10. It extends from 19 into the reaction chamber 10. The exhaust gas supply conduit 8 penetrates the catalytic converter 9.

The exhaust gas discharge conduit 11 is open to the reaction chamber 10 on the first surface 19. The exhaust gas supplied through the exhaust gas supply conduit 8 is directed in the region of the second surface 20 of the reaction chamber 10 facing the downstream end 15 of the exhaust gas supply conduit 8 and then passes through the SCR catalytic converter 9 and subsequently to the second. It flows through the surface 19 of 1 to the region of the exhaust gas discharge conduit 11. The exhaust gas discharge conduit 11 surrounds the exhaust gas supply conduit 8 adjacent to the first surface 19 of the reaction chamber 10, partially outwardly, preferably concentrically.

In the embodiment of FIG. 1, in the common assembly that also supplies the exhaust gas manifold 7, the mixing and disassembling section 14, the exhaust gas supply conduit 8, and additionally the silencer 21, the exhaust gas undergoes a direction change from the exhaust gas manifold 7. It is configured so that it can be supplied to each mixing and decomposition section 14 without using it. This is preferable as described above. On the other hand, an embodiment in which a single direction change is performed when the exhaust gas flows from the exhaust gas manifold 7 to the region of the mixing and decomposition section 14 and thus to the region of the exhaust gas supply conduit 8, that is, the direction change is preferable. Is performed at an angle of up to 90 °, and there may be an embodiment performed when transitioning from the exhaust gas manifold 7 to the exhaust gas supply conduit 8 and thus to the region of the mixing and decomposition section 14. When it is necessary to change the direction of the exhaust gas multiple times due to the construction space in the internal combustion engine, according to the present invention, the exhaust gas manifold 7, the exhaust gas supply conduit 8, the mixing and decomposition section 14, and the compensation element 21 are supplied. The assembly preferably has the exhaust gas undergoing up to three diversions from the exhaust gas manifold 7 or up to 270 ° diversion of the exhaust gas between the exhaust gas manifold 7 and the mixing and decomposition section 14. It is configured to be supplied to the mixing and decomposing section 14 after two diversions or a maximum 180 ° diversion of the exhaust gas between the exhaust gas manifold 7 and the mixing and decomposing section 14. However, it is preferred to turn the exhaust gas up to 90 ° between the exhaust manifold 7 and the mixing and decomposition section 14.

It is most preferable that the exhaust gas is supplied from the exhaust gas manifold 7 in the direction of the mixing and decomposition section 14 without changing the direction.

The common assembly constituting the exhaust gas manifold 7, the mixing and disassembling section 14, and the silencer 21 is preferably exhaust gas to each exhaust gas manifold 7 on the cylinder side, which is the furthest from the SCR catalytic converter 9 or the reaction chamber 10. The exhaust gas opening position 16 to the exhaust gas manifold 7 on the cylinder side, where the distance between the opening position 16 and the SCR catalytic converter 9 or the reaction chamber 10 is the furthest from the SCR catalytic converter 9 or the reaction chamber 10, and the SCR catalytic converter. The distance between the exhaust gas opening position 16 to the exhaust gas manifold 7 on the cylinder side, which is the closest to the 9 or the reaction chamber 10, corresponds to a maximum of 4 times, preferably a maximum of 3 times, and particularly preferably a maximum of 2 times. It is configured as follows.

In the illustrated embodiment, the reaction chamber 10 and the SCR catalytic converter 9 are arranged upstream of the exhaust gas turbocharger 5 on the exhaust gas flow side. The reaction chamber 10 and the SCR catalytic converter 9 may be arranged downstream of the exhaust gas turbocharger on the exhaust gas flow side. Further, the reaction chamber 10 and the SCR catalytic converter 9 may be connected between the high-pressure exhaust gas turbocharger and the low-pressure exhaust gas turbocharger on the exhaust gas flow side.

The details described above are particularly suitable for applications in two-stroke internal combustion engines that can also be operated with residual oil, heavy oil, or natural gas. However, the present invention can also be used in a 4-cycle internal combustion engine.

1 Internal combustion engine 2 Exhaust gas supercharging system 3 Exhaust gas aftertreatment system 4 Cylinder 5 Exhaust gas turbocharger 6 Turbine 7 Exhaust gas manifold 8 Exhaust gas supply conduit 8a Part 8b Part 9 SCR catalytic converter 10 Reaction chamber 11 Exhaust gas exhaust conduit 12 Introducing device 13 Injection cone 14 Mixing and decomposition section 15 End 16 Exhaust gas opening position 17 Flow 18 Diffuser 19 Face 20 Face 21 Silent device 22 Silent chamber 23 Silent chamber 24 Silent chamber 25 Silent chamber 25 Opening 26 Opening 27 Opening

Claims (15)

A mixing device for an exhaust gas aftertreatment system of an internal combustion engine, particularly an SCR exhaust gas aftertreatment system, that is, a mixing device for mixing a reducing agent precursor, particularly an ammonia precursor such as urea, and exhaust gas, and a catalytic converter. In particular, for introducing the exhaust gas supply conduit (8) for inducing the exhaust gas to the SCR catalytic converter (9) and the reducing agent precursor material disposed in the exhaust gas supply conduit (8) into the exhaust gas. An introduction device (12) and a mixing and decomposition section (14) arranged downstream of the introduction device (12) and provided by the exhaust gas supply conduit (8), wherein the exhaust gas is used as the reducing agent precursor. In a mixing apparatus having a mixing and decomposition section (14) for mixing and decomposing the reducing agent precursor to produce the reducing agent upstream of the catalytic converter.
The exhaust gas supply conduit (8) is provided with a silencer (21) in the region of the mixing and decomposition section (14) .
The silencer (21) has at least one silencer chamber, which is connected to the exhaust gas supply conduit (8) through at least one opening.
At least one muffling chamber is connected to the exhaust gas supply conduit (8) in the region of the mixing and disassembling section (14) downstream of the introduction device (12) through at least one opening. The distance of the opening from the introduction device (12) corresponds to a maximum of 1 time or a minimum of 2 times the diameter of the exhaust gas supply conduit (8) in the region of the introduction device (12). A mixing device characterized by that. A mixing device for an exhaust gas aftertreatment system of an internal combustion engine, particularly an SCR exhaust gas aftertreatment system, that is, a mixing device for mixing a reducing agent precursor, particularly an ammonia precursor such as urea, and exhaust gas, and a catalytic converter. In particular, for introducing the exhaust gas supply conduit (8) for inducing the exhaust gas to the SCR catalytic converter (9) and the reducing agent precursor material disposed in the exhaust gas supply conduit (8) into the exhaust gas. An introduction device (12) and a mixing and decomposition section (14) arranged downstream of the introduction device (12) and provided by the exhaust gas supply conduit (8), wherein the exhaust gas is used as the reducing agent precursor. In a mixing apparatus having a mixing and decomposition section (14) for mixing and decomposing the reducing agent precursor to produce the reducing agent upstream of the catalytic converter.
The exhaust gas supply conduit (8) is provided with a silencer (21) in the region of the mixing and decomposition section (14).
The silencer (21) has at least one silencer chamber, which is connected to the exhaust gas supply conduit (8) through at least one opening.
At least one of the muffler chambers of the muffler (21), through at least one of the openings , downstream of the introduction device (12), in the region of the mixing and disassembling section (14). , The distance of the opening from the introduction device (12) is the distance of the exhaust gas supply conduit (8) in the region of the introduction device (12). A mixing device characterized in that it corresponds to a maximum of 1 times or a minimum of 2 times the diameter. A mixing device for an exhaust gas aftertreatment system of an internal combustion engine, particularly an SCR exhaust gas aftertreatment system, that is, a mixing device for mixing a reducing agent precursor, particularly an ammonia precursor such as urea, and exhaust gas, and a catalytic converter. In particular, for introducing the exhaust gas supply conduit (8) for inducing the exhaust gas to the SCR catalytic converter (9) and the reducing agent precursor material disposed in the exhaust gas supply conduit (8) into the exhaust gas. An introduction device (12) and a mixing and decomposition section (14) arranged downstream of the introduction device (12) and provided by the exhaust gas supply conduit (8), wherein the exhaust gas is used as the reducing agent precursor. In a mixing apparatus having a mixing and decomposition section (14) for mixing and decomposing the reducing agent precursor to produce the reducing agent upstream of the catalytic converter.
The exhaust gas supply conduit (8) is provided with a silencer (21) in the region of the mixing and decomposition section (14).
The silencer (21) has at least one silencer chamber, which is connected to the exhaust gas supply conduit (8) through at least one opening.
The distance of the mixing and decomposition section (14) from the introduction device (12) is once the diameter of the exhaust gas supply conduit (8) in the region of the introduction device (12), and the introduction device (12). In the region corresponding to twice the diameter of the exhaust gas supply conduit (8), an opening such that the muffling chamber of the muffler (21) is connected to the exhaust gas supply conduit (8). A mixing device characterized in that the part is not formed. A mixing device for an exhaust gas aftertreatment system of an internal combustion engine, particularly an SCR exhaust gas aftertreatment system, that is, a mixing device for mixing a reducing agent precursor, particularly an ammonia precursor such as urea, and exhaust gas, and a catalytic converter. In particular, for introducing the exhaust gas supply conduit (8) for inducing the exhaust gas to the SCR catalytic converter (9) and the reducing agent precursor material disposed in the exhaust gas supply conduit (8) into the exhaust gas. An introduction device (12) and a mixing and decomposition section (14) arranged downstream of the introduction device (12) and provided by the exhaust gas supply conduit (8), wherein the exhaust gas is used as the reducing agent precursor. In a mixing apparatus having a mixing and decomposition section (14) for mixing and decomposing the reducing agent precursor to produce the reducing agent upstream of the catalytic converter.
The exhaust gas supply conduit (8) is provided with a silencer (21) in the region of the mixing and decomposition section (14).
The silencer (21) has at least one silencer chamber, which is connected to the exhaust gas supply conduit (8) through at least one opening.
At least one of the muffler chambers of the silencer (21) is coupled to the exhaust gas supply conduit (8) through at least one of the openings upstream of the introduction device (12). A mixing device characterized by being present. Any one of claims 1 to 4, wherein the silencer (21) constitutes a Helmholtz resonator and / or a λ / 4 resonator and / or a sound absorbing silencer. The mixing device described in the section . The mixing device according to claim 4 , wherein at least one of the muffling chambers of the muffler (21) constitutes a λ / 4 resonator. The mixing device according to claim 4 or 5 , wherein at least one of the muffling chambers of the muffler (21) constitutes a Helmholtz resonator. The mixing device according to any one of claims 4 to 6, wherein at least one of the muffling chambers of the muffler (21) constitutes a sound absorbing type muffler. Claims 4 to 7 , wherein at least one device (18a, 18b) for rapidly increasing the cross section inside the exhaust gas supply conduit (8) is arranged in the region of the mixing device. The mixing device according to any one . At least one device (18a, 18b) for rapidly increasing the cross section is attached upstream or downstream of the introduction device (12), and the device (18a, 18b) for rapidly increasing the cross section is attached. However, when mounted downstream of the introduction device, the distance of the device (18a, 18b) for rapidly increasing the cross section from the introduction device (12) is the distance in the region of the introduction device (12). The mixing device according to claim 9 , wherein the diameter of the exhaust gas supply conduit (8) corresponds to a minimum of twice the diameter. The mixing and disassembling section (14) and the muffler (21), or the exhaust gas supply conduit (8) and the muffler (21) are integrated into a common assembly. The mixing device according to any one of claims 1 to 7 . An exhaust gas aftertreatment system (3) for an internal combustion engine (1), particularly an SCR exhaust gas aftertreatment system for an internal combustion engine operated with heavy oil or residual oil, at least disposed in a reaction chamber (10). It has one catalytic converter (9), particularly an SCR catalytic converter, an exhaust gas supply conduit (8) leading to the reaction chamber (10), and an exhaust gas discharge conduit (11) extending from the reaction chamber (10). In the exhaust gas aftertreatment system
(3) An exhaust gas aftertreatment system comprising the mixing device according to any one of claims 1 to 8 . 12. The exhaust gas aftertreatment system according to claim 12 , wherein the exhaust gas manifold (7) is integrated into a common assembly together with the mixing and disassembling section (14) and the silencer (21). The exhaust gas opening position (16) to the exhaust gas manifold (7) on the cylinder side, which is the furthest from the SCR catalytic converter (9) or the reaction chamber (10), and the SCR catalytic converter (9) or the reaction chamber (10). ) And the exhaust gas opening position (16) to the exhaust gas manifold (7) on the cylinder side, where the distance between the SCR catalytic converter (9) or the reaction chamber (10) is the furthest from the exhaust gas opening position (16) and the SCR catalyst. The distance between the exhaust gas opening position (16) to the exhaust gas manifold (7) on the cylinder side, which is the closest to the converter (9) or the reaction chamber (10), is up to 4 times, preferably up to 3 times. The exhaust gas aftertreatment system according to claim 12 or 13 , wherein a common assembly is configured so as to correspond to a doubling, particularly preferably a maximum of doubling. A plurality of cylinders (4), at least one exhaust gas manifold (7) common to the group of the cylinders (4), and the exhaust gas aftertreatment system (3) according to any one of claims 12 to 14. The internal combustion engine (1), wherein the exhaust gas flows from the exhaust gas manifold (7) through the exhaust gas aftertreatment system (3) and downstream of the exhaust gas aftertreatment system (3). An internal combustion engine (1) that can be guided through at least one exhaust gas turbocharger (5) of the exhaust gas supercharging system (2) of (1).

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