KR102299818B1 - Exhaust gas after-treatment system and internal combustion engine - Google Patents

Abstract

The exhaust gas aftertreatment system 3 of an internal combustion engine according to the invention, ie the SCR exhaust gas aftertreatment system, has an SCR catalytic converter 9 housed in a reaction chamber 10 , to and from the reaction chamber 10 . thus having an exhaust gas supply line 8 leading to the SCR catalytic converter 9 , and an exhaust gas exhaust line 11 leading from the reaction chamber 10 and thus from the SCR catalytic converter 9 , reducing agent , in particular having an inlet device 16 attached to the exhaust gas supply line 8 for introducing ammonia or ammonia precursor material into the exhaust gas, in the reaction chamber 10 or upstream of the SCR catalytic converter 9 . An exhaust gas aftertreatment system having a mixing section (18) provided by an exhaust gas supply line (18) downstream of an inlet device (16) for mixing exhaust gas and a reducing agent, in a reaction chamber (10), At least one blow-down device ( 24 ) serving to purge the SCR catalytic converter ( 9 ) is arranged.

Description

EXHAUST GAS AFTER-TREATMENT SYSTEM AND INTERNAL COMBUSTION ENGINE

The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine. The invention also relates to an internal combustion engine having an exhaust gas aftertreatment system.

In combustion processes in, for example, stationary internal combustion engines employed in power plants, and in combustion processes in non-stationary internal combustion engines employed, for example in ships, nitrogen oxides are formed, which are usually methane, coal, It is formed during the combustion of fossil fuels containing sulfur, such as crude oil, heavy oil, or light oil. For this reason, the above-described internal combustion engine is assigned with an exhaust gas aftertreatment system serving to purify, in particular, denitrate, exhaust gas exiting the internal combustion engine.

In order to reduce nitrogen oxides in exhaust gases, so-called SCR catalytic converters are mainly employed in exhaust gas aftertreatment systems known in practice. In the SCR catalytic converter, selective catalytic reduction of nitrogen oxides occurs, in which case ammonia (NH ₃ ) is required as a reducing agent for the reduction of nitrogen oxides. For this purpose, ammonia or an ammonia precursor material, such as urea, for example, is introduced in liquid form into the exhaust gas upstream of the SCR catalytic converter, in which case the ammonia or ammonia precursor material is mixed with the exhaust gas upstream of the SCR catalytic converter. are mixed For this purpose, according to practice, between the inlet of ammonia or ammonia precursor material and the SCR catalytic converter, a mixing section is provided.

Although exhaust gas aftertreatment, in particular nitrogen oxide reduction, can already be successfully achieved using exhaust gas aftertreatment systems known from practice, there is a need for further improvement of exhaust gas aftertreatment systems. In particular, there is a need to enable efficient exhaust gas after-treatment by using the exhaust gas after-treatment system of a compact design.

Starting from this point, the subject of the present invention is based on the creation of a novel type of exhaust gas aftertreatment system for an internal combustion engine and an internal combustion engine having such an exhaust gas aftertreatment system.

This problem is solved by an exhaust gas aftertreatment system of an internal combustion engine according to claim 1 . According to the invention, at least one blow-down device serving to purge the SCR catalytic converter is arranged in the reaction chamber. Accordingly, it is possible to prevent the SCR catalytic converter from becoming clogged as a result of soot particles being deposited on the SCR catalytic converter. A very efficient exhaust gas aftertreatment can be ensured using the exhaust gas aftertreatment system of a compact design.

According to another advantageous development of the invention, the or each blow-down device is arranged on a surface of the SCR catalytic converter extending transversely to the flow direction, in particular transverse to the flow direction, preferably perpendicular to the flow direction. On the upstream surface of the honeycomb body of the SCR catalytic converter, which extends to the top, it is oriented in such a way as to induce a vortex flow or vortex flow. Thereby, it is possible to very effectively prevent the SCR catalytic converter from becoming clogged as a result of soot particles being deposited on the SCR catalytic converter. Efficient exhaust gas purification can be ensured by using the exhaust gas aftertreatment system of a compact design.

According to another advantageous refinement of the invention, the reaction chamber has a wall of circular cross-section, in particular a circular wall. This is desirable for the formation of a vortex flow or a vortex flow. This enables very efficient exhaust gas aftertreatment with a compact design.

According to another advantageous development of the invention, each blow-down device is arranged adjacent to a wall of a reaction chamber having a circular cross section, the blows coming out of said wall and entering the reaction chamber, ie the blow-down cone is at least one Intersects the ejection cones of other blow-down devices. This is desirable for the formation of vortex flows or vortex flows and for full-area purging of soot particles. This enables very efficient exhaust gas aftertreatment with a compact design.

According to another further advantageous refinement, the exhaust gas supply line runs through the downstream end towards the reaction chamber receiving the SCR catalytic converter, in the reaction chamber between the downstream end of the exhaust gas supply line and the SCR catalytic converter. , a device for increasing the exhaust gas back pressure is disposed upstream of the SCR catalytic converter. With the aid of a device for increasing the exhaust gas back pressure on the upstream side of the SCR catalytic converter, the exhaust gas flow upstream of the SCR catalytic converter is inhibited, as a result, ie in a circumferential and also radial view, the SCR catalyst An even supply of exhaust gas flow to the converter can be achieved. For this reason, efficient exhaust gas purification can be ensured using the exhaust gas after-treatment system of a compact design. In addition, soot particles can deposit in the device and increase the exhaust gas backpressure, in which case the soot particles can no longer enter the zone of the SCR catalytic converter and clog the SCR catalytic converter. It also serves to ensure efficient exhaust gas purification using an exhaust gas aftertreatment system of a compact design.

Preferably, the or each blow-down device is disposed between the device for increasing the exhaust gas back pressure in the reaction chamber and the SCR catalytic converter. In this case, the or each blow-down device serves at least for purging the SCR catalytic converter and preferably for purging the device for increasing the exhaust gas backpressure. According to this further improvement, a very efficient exhaust gas aftertreatment is possible in a compact design.

An internal combustion engine according to the invention is defined in claim 11 .

Further preferred developments of the present invention are obtained from the dependent claims and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments of the present invention will be described in more detail with reference to the drawings, but without being limited thereto. In the drawing,
1 is a schematic perspective view of an internal combustion engine having an exhaust gas aftertreatment system according to the present invention;
Fig. 2 is a detailed view of the exhaust gas aftertreatment system of Fig. 1;
Fig. 3 is a detailed view of Fig. 2;
FIG. 4 is a cross-sectional view of the detailed view of FIG. 3 .

The present invention relates to an exhaust gas aftertreatment system of an internal combustion engine, for example a stationary internal combustion engine in a power plant or a non-stationary internal combustion engine employed on a ship. In particular, exhaust gas aftertreatment systems are employed in diesel engines of ships operated on heavy oil.

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 a stationary or stationary internal combustion engine, in particular a stationary working internal combustion engine of a ship. The exhaust gas exiting the cylinder of the internal combustion engine 1 is used in the exhaust gas charging system 2 to obtain mechanical energy for compressing the charging air supplied to the internal combustion engine 1 from the thermal energy of the exhaust gas. 1 shows an exhaust gas supercharging system 2 comprising a plurality of exhaust gas turbochargers, namely a first exhaust gas turbocharger 4 on the high pressure side and a second exhaust gas turbocharger 5 on the low pressure side. An internal combustion engine (1) with The exhaust gas exiting the cylinder of the internal combustion engine 1 initially flows through the high pressure turbine 6 of the first exhaust gas turbocharger 4 and is expanded in this high pressure turbine, the energy obtained in this process being: It is used to compress the charge air in the high-pressure compressor of the first exhaust gas turbocharger 4 . When viewed from the flow direction of the exhaust gas, the second exhaust gas turbocharger 5 is disposed on the downstream side of the first exhaust gas turbocharger 4, so that the high-pressure turbine ( The exhaust gas that has passed through 6) is guided via the second exhaust gas turbocharger 5 , that is, via the low pressure turbine 7 of the second exhaust gas turbocharger 5 . In the low pressure turbine 7 of the second exhaust gas turbocharger 5 , the exhaust gas is further expanded, and the energy obtained in this process, in the low pressure compressor of the second exhaust gas turbocharger 5 , likewise the internal combustion engine 1 ) is used to compress the charge air supplied to the cylinder.

In addition to the exhaust gas supercharging system 2 comprising the exhaust gas turbochargers 4 , 5 , the internal combustion engine 1 includes an exhaust gas aftertreatment system 3 which is an SCR exhaust gas aftertreatment system. The SCR exhaust gas aftertreatment system 3 is connected between the high pressure turbine 6 and the low pressure turbine 7 of the first exhaust gas turbocharger 4 , and thus the high pressure of the first exhaust gas turbocharger 4 . The exhaust gas exiting the turbine 6 may initially be conducted via the SCR exhaust gas aftertreatment system 3 before reaching the region of the low pressure turbine 7 of the second exhaust gas turbocharger 5 . have.

1 shows an exhaust gas supply line 8 through which the exhaust gas exits the high-pressure turbine 6 of the first exhaust gas turbocharger 4 and is guided toward the SCR catalytic converter 9 disposed in the reaction chamber 10 . shows 1 also shows an exhaust gas discharge line 11 serving to discharge the exhaust gas from the SCR catalytic converter 9 towards the low pressure turbine 7 of the second exhaust gas turbocharger 5 . The exhaust gases from the low pressure turbine 7 flow via line 21 , in particular outdoors. An exhaust gas supply line 8 leading to the reaction chamber 10 and thus to the SCR catalytic converter 9 arranged in the reaction chamber 10 , and from the reaction chamber 10 and thus from the SCR catalytic converter 9 . The exhaust gas discharge line 11 that follows is connected via a bypass 12 in which a blocking element 13 is integrated. With the blocking element 13 closed, the bypass 12 is closed, so that no exhaust gas flows via the bypass. In contrast, the exhaust gas, in particular when the blocking element 13 is open, passes via the bypass 12 , ie through the reaction chamber 10 and thus an SCR catalytic converter arranged in the reaction chamber 10 . It can flow past (9). FIG. 2 shows the flow of exhaust gas through the exhaust gas aftertreatment system 3 with arrow 14 with the bypass 12 closed through the blocking element 13 , the exhaust gas supply line 8 . It passes through the downstream end (15) towards the reaction chamber (10), and in the region of the downstream end (15) of the exhaust gas supply line (8) the exhaust gas has a flow direction change of about 180°, It is evident in FIG. 2 that after this flow direction change the exhaust gas is guided via the SCR catalytic converter 9 .

The exhaust gas supply line 8 of the exhaust gas aftertreatment system 3 is equipped with an inlet device 16 , through which the reducing agent, in particular nitrogen oxides of the exhaust gas in the region of the SCR catalytic converter 9 . Ammonia or ammonia precursor material necessary to convert in a predetermined manner may be introduced into the exhaust gas stream. The inlet device 16 of this exhaust gas aftertreatment system 3 is preferably an injection nozzle through which ammonia or ammonia precursor material is injected into the exhaust gas stream in the exhaust gas supply line 8 . FIG. 2 shows with cone 17 the injection of reducing agent into the exhaust gas stream in the region of the exhaust gas supply line 8 .

The section of the exhaust gas aftertreatment system 3 , which is located downstream of the inlet device 16 and upstream of the SCR catalytic converter 9 , as viewed in the flow direction of the exhaust gas, is described as a mixing section. Specifically, the exhaust gas supply line 8 provides a mixing section 18 on the downstream side of the inlet device 16 , in which the exhaust gas is to be mixed with the reducing agent upstream of the SCR catalytic converter 9 . can

The exhaust gas supply line 8 runs through the downstream end 15 towards the reaction chamber 10 . A baffle element 20 displaceable with respect to the downstream end 15 of the exhaust gas supply line 8 is attached to the downstream end 15 of the exhaust gas supply line 8 . In the exemplary embodiment shown, the baffle element 20 is linearly displaceable with respect to the downstream end 15 of the exhaust gas supply line 8 leading towards the reaction chamber 10 . In order to block the exhaust gas supply line 8 at the downstream end 15 or to open the exhaust gas supply line at the downstream end 15 , a baffle element 20 is installed downstream of the exhaust gas supply line 8 . It is displaceable with respect to the side end 15 . Specifically, when the baffle element 20 blocks the exhaust gas supply line 8 at the downstream end 15 , then the exhaust gas receives the SCR catalytic converter 9 or the SCR catalytic converter 9 . In order to guide the reaction chamber 10 completely through, it is preferred that the blocking element 13 of the bypass 12 is open. Specifically, when the baffle element 20 opens the downstream end 15 of the exhaust gas supply line 8 , the blocking element 13 of the bypass 12 can be completely closed or at least partially open. can

Specifically, when the baffle element 20 opens the downstream end 15 of the exhaust gas supply line 8 , the The relative positions are, in particular, the exhaust gas mass flow through the exhaust gas supply line 8 and/or the temperature of the exhaust gases in the exhaust gas supply line 8 and/or the entry into the exhaust gas flow through the inlet device 16 . It depends on the amount of reducing agent used.

The other function of the baffle element 20 with the downstream end 15 of the exhaust gas supply line 8 open is that any droplets of reducing agent present in the exhaust gas stream will be removed from the zone of the SCR catalytic converter 9 . In order to prevent the above-mentioned reducing agent from reaching the baffle element, it is in the baffle element where it is captured and atomized. In particular, by the relative position of the baffle element 20 with respect to the downstream end 15 of the exhaust gas supply line 8 with the downstream end 15 open, in the region of the baffle element 20 In the region of the downstream end 15 of the exhaust gas supply line 8 , the exhaust gas is diverted more towards the radially innerly arranged section or towards the radially outerly arranged section of the SCR catalytic converter 9 . More may be determined whether it is directed or steered.

According to a preferred embodiment, the exhaust gas supply line 8 expands in a funnel-shaped manner in the region of the downstream end 15 to form a diffuser. For this reason, the flow cross-section of the exhaust gas supply line 8 in the region of the downstream end 15 is increased, and as seen in the flow direction of the exhaust gas, as is particularly clear in FIG. 2 , the exhaust gas supply line 8 ) upstream of the downstream end 15 , the flow cross-section of the exhaust gas supply line is initially reduced. Therefore, FIG. 2 shows that the flow cross section of the exhaust gas supply line 8 is, when viewed from the flow direction of the exhaust gas, on the downstream side of the inflow device 16 for the reducing agent, it is initially approximately constant, but then tapers first. and finally enlarged in the region of the downstream end 15 .

In this case, the widening of the flow cross section at the downstream end 15 of the exhaust gas supply line 8 is that the tapered exhaust gas supply line 8 at the front of the downstream end 15 is initially It is preferably carried out via a section of the exhaust gas supply line 8 that is shorter than the via section.

The baffle element 20 is preferably curved on the side 22 facing the exhaust gas supply line 8 , preferably bell-shaped, to form a flow guide for the exhaust gas. Thus, in the baffle element 20 , the side on the radially inner section of the baffle element 20 facing the downstream end 15 of the exhaust gas supply line 8 is downstream of the exhaust gas supply line 8 . The distance to the side end 15 is shorter than the side on the radially outer section of the baffle element 20 . Accordingly, the baffle element 20 is drawn or curved from the center towards the downstream end 15 of the exhaust gas supply line 8 against the flow direction of the exhaust gas.

As already explained, the exhaust gas supply line 8 runs through its downstream end 15 towards the reaction chamber 10 housing the SCR catalytic converter 9 . Here, the exhaust gas supply line 8 passes through the lower side of the reaction chamber 10 according to FIG. 2 and is adjacent to the upper side 23 of the reaction chamber 10 through the downstream end 15 thereof. The exhaust gas exits the exhaust gas supply line at the downstream end 15 , as already explained, is then diverted 180° before flowing via the SCR catalytic converter 9 .

As is particularly evident in FIG. 3 , the device 25 for increasing the exhaust gas back pressure is arranged between the SCR catalytic converter 9 and the downstream end 15 of the exhaust gas supply line 8 . placed upstream of The device 25 for increasing such exhaust gas back pressure may be, for example, a grid, a perforated plate, or the like.

With the aid of the device 25 , which increases the exhaust gas back pressure upstream of the SCR catalytic converter 9 , the exhaust gas flow upstream of the SCR catalytic converter 9 is blocked, and as a result, ie circumferentially and Also, when viewed in the radial direction, it can be achieved that the exhaust gas flow is evenly supplied to the SCR catalytic converter 9 .

The device 25 for increasing the exhaust gas back pressure also has the advantage that soot particles contained in the exhaust gas can be deposited in the device. Said soot particles deposited in the device 25 for increasing the exhaust gas back pressure no longer enter the zone of the SCR catalytic converter 9 and block the SCR catalytic converter, ie the honeycomb body 27 of the SCR catalytic converter. 3 and 4 show a plurality of honeycomb bodies 27 of the SCR catalytic converter 9 having a circular cross section.

In addition, the device 25 for increasing the exhaust gas back pressure is at most 2 times, preferably at most 1 times, very preferably the free-flow cross-section of the SCR catalytic converter 9 or the honeycomb body 27 of the SCR catalytic converter 9 . It has a free-flow cross-section equivalent to a maximum of 0.5 times. In this way, on the one hand, it can be ensured that the exhaust gas flows evenly over the SCR catalytic converter 9 , and on the other hand the soot particles are already in the region of the device 25 which increases the exhaust gas backpressure. It can be ensured that deposits no longer reach the zone of the SCR catalytic converter 9 .

Preferably, the thickness or length of the device 25 for increasing the exhaust gas backpressure as viewed in the flow direction or in the exhaust gas flow direction and the SCR catalytic converter 9 or SCR catalytic converter as viewed in the flow direction or exhaust gas flow direction The ratio between the thicknesses or lengths of the honeycomb body 27 of (9) corresponds to at least 1:50, preferably at least 1:100, and very preferably at least 1:200.

Preferably, a distance corresponding to the distance between the SCR catalytic converter 9 and the device 25 for increasing the exhaust gas backpressure when viewed in the flow direction or in the exhaust gas flow direction, and the SCR catalytic converter 9 when viewed in the flow direction ) or the thickness or length of the honeycomb body 27 of the SCR catalytic converter 9 corresponds to at most 2:1, preferably 1:1, very preferably 1:2.

With the device 25 for increasing the exhaust gas back pressure arranged in the reaction chamber 10 , it can be ensured that the exhaust gas is constantly supplied to the SCR catalytic converter 9 . By increasing the exhaust gas back pressure, the exhaust gas flow is blocked, thereby ensuring an even distribution of the exhaust gas to the SCR catalytic converter 9 . Another advantage of the device 25 for increasing the exhaust gas back pressure is that it also assumes the function of a pre-separator in which soot particles contained in the exhaust gas can be deposited. For this reason, it is possible to prevent soot particles from reaching the SCR catalytic converter 9 without obstruction and clogging the SCR catalytic converter.

In the reaction chamber 10 , at least one blow-down device 24 is arranged, which serves to purge the SCR catalytic converter 9 . In the preferred exemplary embodiment shown, the or each blow-down device 24 is arranged in a reaction chamber 10 , in which an SCR catalytic converter 9 and additionally increasing the exhaust gas backpressure are arranged. A device (25) is housed, said or each blow-down device (24) being located between the device (25) for increasing said exhaust gas backpressure as viewed in the flow direction of the exhaust gas and the SCR catalytic converter (9). is placed. The or each blow-down device 24 is preferably an air nozzle. In order to prevent clogging of the SCR catalytic converter 9 and preferably also of the device 25 which increases the exhaust gas backpressure, the or each blow-down device 24 comprises at least the SCR catalytic converter 9 ) serves to purge the SCR catalytic converter 9 with respect to the soot particles deposited in the , and preferably also serves to purge the device 25 for increasing the exhaust gas back pressure. The or each blow-down device 24 is preferably on the surface of the SCR catalytic converter 9 extending transverse to the flow direction, ie extending perpendicular to the flow direction. ) on the upstream surface of the honeycomb body 27, is oriented in such a way as to induce a vortex flow or vortex flow.

4 shows here on the upstream surface of the SCR catalytic converter 9 extending in the reaction chamber 10 , ie perpendicular to the flow direction or exhaust gas flow direction, and preferably in the flow direction or exhaust gas flow. The or each blow-down device 24 is preferably oriented in such a way that a vortex flow or vortex flow is also generated on the downstream surface of the device 25 for increasing the exhaust gas backpressure extending perpendicular to the direction. so as to show the preferred orientation of the or each blow-down device 24 , in which case the surfaces are facing the or each blow-down device 24 in each case. Purging of soot particles from the SCR catalytic converter 9 , ie from the honeycomb body 27 of the SCR catalytic converter, preferably also from the device 25 for increasing the exhaust gas back pressure, by means of a vortex flow or a vortex flow It can happen very efficiently.

The reaction chamber 10 , in which the SCR catalytic converter 9 and preferably also a device 25 for increasing the exhaust gas backpressure is housed, is preferably round in cross section, in particular circular, and It is desirable to have a wall 19 extending between the lower side 22 and the upper side 23 . At least inside the wall 19 , which is round or circular in cross-section, an interior space of the reaction chamber 10 accommodating at least the catalytic converter 9 is defined. A device 25 which serves to purge the SCR catalytic converter 9 and preferably also increases the exhaust gas backpressure, by combining the wall 19 described above with the orientation of the or each blow-down device 24 . ), a vortex flow or a vortex flow, which serves to purge, can be very advantageously configured in the reaction chamber 10 with respect to the soot particles deposited on the purging objects.

Preferably, a plurality of blow-down devices 24 , preferably at least three and very preferably at least four blow-down devices 24 , are arranged in the reaction chamber 10 .

Here, the blow-down device 24 is arranged adjacent to a reaction chamber 10 having a circular cross section, and blown air or compressed air enters the reaction chamber 10 from the walls 19 of the reaction chamber, That is, the ejection cone 26 intersects the ejection cone 26 of at least one other blow-down device 24 and thus partially overlaps. For this reason, on the above-mentioned surfaces, a full-area purging of the SCR catalytic converter 9 and preferably also of the device 25 for increasing the exhaust gas backpressure can be implemented or ensured.

According to the present invention, effective exhaust gas post-treatment is possible with a compact design.

In the case of the internal combustion engine 1 of FIG. 1 , the exhaust gas aftertreatment system 3 is arranged upright upstream of the exhaust gas supercharging system 2 . Access to the cylinders of the internal combustion engine 1 is free, but the access of the exhaust gas turbochargers 4 and 5 is limited. However, when maintenance work is required on the exhaust gas turbochargers 4 and 5, the reaction chamber 10 can be simply disassembled.

In contrast to the configuration in which the exhaust gas after-treatment system 3 is placed upright on the upstream side of the exhaust gas supercharging system 2 shown in FIG. 1 , next to the exhaust gas supercharging system 2, the exhaust gas after-treatment system A configuration in which (3) is horizontally disposed at an angle of 90° is also possible, but in the case of such a horizontal configuration, the length of the configuration is increased. However, in this case, there is no need to disassemble the reaction chamber 10, so that the internal combustion engine 1 and the exhaust gas supercharging system 2 can be used for maintenance work without restriction.

1: internal combustion engine 2: exhaust gas supercharging system
3: exhaust gas after-treatment system 4: exhaust gas turbocharger
5: exhaust gas turbocharger 6: high pressure turbine
7: low pressure turbine 8: exhaust gas supply line
9: SCR catalytic converter 10: reaction chamber
11: exhaust gas discharge line 12: bypass
13: blocking element 14: exhaust gas guide
15: end 16: inlet device
17: injection cone 18: mixing section
19: wall 20: baffle element
21: line 22: side
23: side 24: blow-down device
25: device for increasing exhaust gas back pressure
26: ejection cone 27: honeycomb body

Claims (12)

An exhaust gas aftertreatment system (3) of an internal combustion engine, comprising an SCR catalytic converter (9) housed in a reaction chamber (10), exhaust gas supply leading to the reaction chamber (10) and thus to the SCR catalytic converter (9) an exhaust gas exhaust line 11 leading from the reaction chamber 10 and thus from the SCR catalytic converter 9, having a line 8 and an exhaust gas supply line for introducing a reducing agent into the exhaust gas 8) having an inlet device 16 attached to it, the exhaust gas downstream of the inlet device 16 for mixing the reducing agent with the exhaust gas at the upstream side of the reaction chamber 10 or the SCR catalytic converter 9 The exhaust gas aftertreatment system with a mixing section 18 provided by a supply line 8 comprises at least one blow-down device serving to purify the SCR catalytic converter 9 in the reaction chamber 10 ( 24) is arranged, the exhaust gas supply line 8 passes toward the reaction chamber 10 through the downstream end 15, and in the reaction chamber 10, a device 25 for increasing the exhaust gas back pressure is provided. disposed on the upstream side of the SCR catalytic converter 9 between the downstream end 15 of the exhaust gas supply line 8 and the SCR catalytic converter 9, said or each blow-down device 24 reacting It is arranged in the chamber (10) between the device (25) for increasing the exhaust gas backpressure and the SCR catalytic converter (9), said or each blow-down device (24) extending transversely to the flow direction An exhaust gas aftertreatment system characterized in that it is oriented in such a way as to cause a vortex flow or a vortex flow on the surface of the SCR catalytic converter (9). delete The vortex flow or An exhaust gas aftertreatment system characterized in that it is oriented in such a way as to induce a vortex flow. 4. Exhaust gas aftertreatment system according to claim 1 or 3, characterized in that the reaction chamber (10) has a wall (19) having a circular cross section. 5. The reaction chamber (10) according to claim 4, wherein each blow-down device (24) is arranged adjacent to a wall (19) of a reaction chamber (10) having a circular cross section, the blows exiting said wall (19). ) exhaust gas aftertreatment system, characterized in that it enters the inside. delete delete 4. Exhaust according to claim 1 or 3, characterized in that the device (25) for increasing the exhaust gas backpressure has a free-flow cross-section corresponding to at most twice the free-flow cross-section of the SCR catalytic converter (9). gas aftertreatment system. 4. A ratio according to claim 1 or 3, between the thickness or length of the device (25) for increasing the exhaust gas backpressure when viewed in the direction of flow and the thickness or length of the SCR catalytic converter (9) when viewed in the direction of flow. , which corresponds to at least 1:50. 4. The SCR according to claim 1 or 3, wherein a distance corresponding to the distance between the SCR catalytic converter (9) and the device (25) for increasing the exhaust gas backpressure when viewed in the direction of flow and the SCR as seen in the direction of flow The exhaust gas aftertreatment system, characterized in that the ratio between the thickness or the length of the catalytic converter (9) corresponds to at most 2:1. An internal combustion engine (1) having an exhaust gas aftertreatment system (3) according to claim 1 or 3. The multistage exhaust gas according to claim 11 , wherein the internal combustion engine has a first exhaust gas turbocharger ( 4 ) comprising a high pressure turbine ( 6 ) and a second exhaust gas turbocharger ( 5 ) comprising a low pressure turbine ( 7 ). An internal combustion engine comprising a supercharging system (2), wherein an exhaust gas aftertreatment system (3) is connected between the high-pressure turbine (6) and the low-pressure turbine (7).

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