CN108952899B

CN108952899B - Exhaust gas aftertreatment system and internal combustion engine

Info

Publication number: CN108952899B
Application number: CN201810473673.7A
Authority: CN
Inventors: A.德林; F.纳那
Original assignee: MAN Energy Solutions SE
Current assignee: MAN Energy Solutions SE
Priority date: 2017-05-17
Filing date: 2018-05-17
Publication date: 2022-03-18
Anticipated expiration: 2038-05-17
Also published as: CN108952899A; FI130680B1; KR102333615B1; FI20185369A1; DE102017110685A1; FI20185369A; JP7033000B2; CH713830A2; KR20180126369A; JP2018194001A; CH713830B1

Abstract

The invention relates to an exhaust gas aftertreatment system and an internal combustion engine. An exhaust gas aftertreatment system (3) of an internal combustion engine comprising: an SCR catalytic converter (9) received in the reactor chamber (10); an exhaust gas supply line (8) leading to the reactor chamber (10) and thus to the SCR catalytic converter (9); an exhaust gas outlet line (11) leading away from the reactor chamber (10) and thus from the SCR catalytic converter (9); an introduction device (16), which is assigned to the exhaust gas supply line (8), for introducing the reducing agent into the exhaust gas. The exhaust gas aftertreatment system (3) further comprises a plurality of blowing devices (24) and a pressure accumulator (25) common to the blowing devices (24), which pressure accumulator (25) extends round or polygonal around the blowing devices (24), wherein the blowing devices (24) can be supplied with a medium for blowing clean the SCR catalytic converter (9).

Description

Exhaust gas aftertreatment system and internal combustion engine

Technical Field

The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine. The invention further relates to an internal combustion engine with an exhaust gas aftertreatment system.

Background

In combustion processes in stationary internal combustion engines, for example for power plants, and in non-stationary internal combustion engines, for example for use on ships, nitrogen oxides are produced, wherein these nitrogen oxides are typically produced during the combustion of sulfur-containing fossil fuels, such as coal, bituminous coal, lignite, mineral oil, heavy fuel oil or diesel fuel. An exhaust gas aftertreatment system for cleaning, in particular for denitrification of exhaust gases leaving an internal combustion engine, is therefore assigned to such an internal combustion engine.

In order to reduce the nitrogen oxides in the exhaust gas, so-called SCR catalytic converters are mainly used in exhaust gas aftertreatment systems known from practice. In an SCR catalytic converter, a selective catalytic reduction of nitrogen oxides takes place, wherein ammonia (NH) is required as a reducing agent for the reduction of the nitrogen oxides₃). For this purpose, ammonia or an ammonia precursor substance, such as, for example, urea, is introduced into the exhaust gas in liquid form upstream of the SCR catalytic converter, wherein the ammonia or ammonia precursor substance is mixed with the exhaust gas upstream of the SCR catalytic converter. For this purpose, a mixing section is conventionally provided between the introduction of ammonia or ammonia precursor substances and the SCR catalytic converter.

Although exhaust gas aftertreatment, in particular nitrogen oxide reduction, has been successfully carried out using exhaust gas aftertreatment systems known from practice which comprise SCR catalytic converters, there is still a need for further improvements of exhaust gas aftertreatment systems. In particular, there is a need to make efficient exhaust gas aftertreatment systems possible with a compact design of such exhaust gas aftertreatment systems.

Disclosure of Invention

Starting from this, the object of the invention is based on the creation of a new exhaust gas aftertreatment system for an internal combustion engine and an internal combustion engine with such an exhaust gas aftertreatment system.

This object is solved by an exhaust gas aftertreatment system of an internal combustion engine according to the invention. The exhaust gas aftertreatment system according to the invention comprises a plurality of gas blowing devices, preferably arranged in the reactor chamber, for blowing clean the SCR catalytic converter, wherein the gas blowing devices can be supplied with a medium for blowing clean the SCR catalytic converter originating from a common pressure accumulator which surrounds the SCR catalytic converter and which extends circularly or polygonally around the gas blowing devices. The invention is based on the knowledge that SCR catalytic converters of exhaust gas aftertreatment systems of internal combustion engines operating with heavy fuel oil or residual oil, for example, have a tendency to clog. In the exhaust gas of such internal combustion engines, therefore, there is a high proportion of ash or soot, wherein the ash and soot are deposited in the region of the SCR catalytic converter and can lead to the SCR catalytic converter becoming clogged. To counteract this, there are blowing devices for blowing the SCR converter clean of ash and soot.

According to the prior art, in the case of blowing devices connected to a pressure line one behind the other, different pressure conditions are formed in the supply compressed air system depending on the position of the respective blowing device when activated. This is caused by the different sizes of gas volumes and extensions upstream of the different blowing devices, as a result of which different pressure drops and/or different pressure rises occur in the case of reflected waves. This has the consequence that a distinctly different cleaning effect can be achieved via the blowing device.

In contrast, the blowing device according to the invention can be supplied uniformly from a common annular or polygonal pressure accumulator for blowing clean the medium of the SCR catalytic converter. Via this symmetrical arrangement, the pressure drop and rise for all blowing devices are almost identical, as a result of which they achieve the same cleaning effect. This is particularly advantageous for blowing the SCR catalytic converter clean of ash and soot.

From the common pressure accumulator, a supply line extends to each gas blowing device, via which the respective gas blowing device can be supplied for blowing clean the medium of the SCR catalytic converter, wherein preferably each supply line is assigned a switchable valve. Via the supply lines extending to the gas blowing devices from the common circular or polygonal shaped pressure accumulator, all gas blowing devices can be easily and reliably supplied with medium for blowing clean the SCR catalytic converter, i.e. again ensuring a uniform pressure drop in the region of each gas blowing device.

According to an advantageous further development, a common pressure accumulator extends around the reactor chamber outside the reactor chamber, wherein each supply line from the pressure accumulator extends through the wall of the reactor chamber up to the blowing device. In particular, if the common pressure accumulator also extends around the reactor chamber, it is positioned outside the actual reactor chamber, wherein the supply line then extends through the wall of the reactor chamber in order to supply the gas blowing device arranged in the reactor chamber with the medium for blowing clean the SCR catalytic converter.

According to an advantageous further development, the common pressure accumulator extends closed in the circulation direction around the SCR catalytic converter and around the gas blowing device which is preferably positioned in the reactor chamber, wherein the common pressure accumulator is preferably formed as a circular or polygonal pipe which extends closed in the circulation direction around the SCR catalytic converter and around the gas blowing device which is positioned in the reactor chamber, and preferably extends closed in the circulation direction around the reactor chamber. Via the pressure accumulator which is closed in the circulation direction, i.e. uninterrupted at any circumferential position, all blowing devices can be particularly advantageously provided for blowing clean the medium of the SCR catalytic converter.

The invention also provides an internal combustion engine with an exhaust gas aftertreatment system according to the invention.

Drawings

Further preferred modifications of the invention result from the following description. Exemplary embodiments of the present invention are explained in more detail through the accompanying drawings, but are not limited thereto. It shows that:

FIG. 1 is a schematic perspective view of an internal combustion engine with an exhaust aftertreatment system according to the invention;

FIG. 2 is a detailed view of the exhaust aftertreatment system of FIG. 1;

FIG. 3 is a detailed view of an exhaust aftertreatment system according to the invention;

FIG. 4 is a detailed view of an exhaust aftertreatment system according to a variation of the invention.

Detailed Description

The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine, for example a stationary internal combustion engine in a power plant or a non-stationary internal combustion engine for use on board a ship. In particular, exhaust gas after-treatment systems are used on diesel internal combustion engines of ships operating with heavy fuel oil.

Fig. 1 shows the arrangement of an internal combustion engine 1 with an exhaust-gas turbocharging system 2 and an exhaust-gas aftertreatment system 3. The internal combustion engine 1 can be a stationary or stationary internal combustion engine, in particular a stationary-operation internal combustion engine of a ship. The exhaust gases leaving the cylinders of the combustion engine 1 are used in an exhaust gas charging system 2 for extracting mechanical energy from the thermal energy of the exhaust gases for compressing the charge air to be supplied to the combustion engine 1.

Fig. 1 therefore shows an internal combustion engine 1 with an exhaust-gas turbocharging system 2, said exhaust-gas turbocharging system 2 comprising a plurality of exhaust-gas turbochargers, namely a first high-pressure-side exhaust-gas turbocharger 4 and a second low-pressure-side exhaust-gas turbocharger 5. The exhaust gases leaving the cylinders of the internal combustion engine 1 initially flow via the high-pressure turbine 6 of the first exhaust-gas turbocharger 1 in which they expand, wherein the energy extracted in the process is used for the high-pressure compressor of the first exhaust-gas turbocharger 4 in order to compress the charge air. Viewed in the flow direction of the exhaust gas downstream of the first exhaust-gas turbocharger 4, a second exhaust-gas turbocharger 5 is arranged, via which second exhaust-gas turbocharger 5 the exhaust gas which has passed through the high-pressure turbine 6 of the first exhaust-gas turbocharger 4 is led, i.e. 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 gases expand further and in the process the energy used in the low-pressure compressor of the second exhaust-gas turbocharger 5 is extracted in order to likewise compress the charge air to be supplied to the cylinders of the internal combustion engine 1.

In addition to an exhaust gas charging system 2 comprising two exhaust gas turbochargers 4 and 5, the internal combustion engine 1 comprises an exhaust gas aftertreatment system 3 which is an SCR exhaust gas aftertreatment system. The SCR exhaust gas aftertreatment system 3 is preferably connected between the high-pressure turbine 6 of the first compressor 5 and the low-pressure turbine 7 of the second exhaust gas turbocharger 5, so that the exhaust gas which therefore leaves the high-pressure turbine 6 of the first exhaust gas turbocharger 4 can initially be conducted via the SCR exhaust gas aftertreatment system 3 before it enters the region of the low-pressure turbine 7 of the second exhaust gas turbocharger 5.

Fig. 1 shows an exhaust gas supply line 8, via which exhaust gas supply line 8 the exhaust gas originating from the high-pressure turbine 6 of the first exhaust gas turbocharger 4 can be conducted in the direction of an SCR catalytic converter 9 arranged in a reactor chamber 10.

Fig. 1 furthermore shows an exhaust gas outlet line 11 for discharging exhaust gas from the SCR catalytic converter 9 in the direction of the low-pressure turbine 7 of the second exhaust gas turbocharger 5. The exhaust gases from the low-pressure turbine 7 flow in particular into the environment via a line 21.

The exhaust gas supply line 8 leading to the reactor chamber 10 and thus to the SCR catalytic converter 9 positioned therein is coupled with the exhaust gas discharge line 11 leading out of the reactor chamber 10 and thus out of the SCR catalytic converter 9 via a bypass pipe 12, into which a shut-off device 13 is incorporated. With the shut-off device 13 closed, the bypass pipe 12 is closed, so that no exhaust gas can flow via the bypass pipe. In contrast, in particular when the shut-off device 13 is open, exhaust gas can flow via the bypass line 12, i.e. through the reactor chamber 10 and thus through the SCR catalytic converter 9 located in the reactor chamber 10. Fig. 2 illustrates the flow of exhaust gases through the exhaust gas aftertreatment system 3 with the bypass line 12 closed via the shut-off device 13 with the arrows 14, wherein it is apparent from fig. 2 that the exhaust gas supply line 8 opens into the reactor chamber 10 via the downstream end 15, wherein the exhaust gases in the region of this end 15 of the exhaust gas supply line 8 undergo a flow diversion of approximately 180 °, wherein the exhaust gases after the flow diversion are conducted via the SCR catalytic converter 9.

The exhaust gas supply line 8 of the exhaust gas aftertreatment system 3 is assigned an introduction device 16, via which introduction device 16 a reducing agent, in particular ammonia or an ammonia precursor substance, can be introduced into the exhaust gas flow, which reducing agent is required in order to convert the nitrogen oxides of the exhaust gas in the region of the SCR catalytic converter 9 in a defined manner. The introduction device 16 of the exhaust gas aftertreatment system 3 is preferably an injection nozzle, via which ammonia or an ammonia precursor substance is injected into the exhaust gas flow in the exhaust gas supply line 8. Fig. 2 shows the injection of the reducing agent into the exhaust gas flow in the region of the exhaust gas supply line 8 by means of a cone 17.

The section of the exhaust gas aftertreatment system 3 which is located downstream of the intake device 16 and upstream of the SCR catalytic converter 9, as seen in the flow direction of the exhaust gas, is described as a mixing section. In particular, the exhaust gas supply line 8 provides a mixing section 18 downstream of the introduction device 16, in which mixing section 18 the exhaust gas can be mixed with the reducing agent upstream of the SCR catalytic converter 9.

The exhaust gas supply line 8 leads via a downstream end 15 to the reactor chamber 10. This downstream end 15 of the exhaust gas supply line 8 is assigned a baffle element 20, which baffle element 20 is movable relative to the downstream end 15 of the exhaust gas supply line 8. In the exemplary embodiment shown, the baffle element 20 is linearly movable relative to the end 15 of the exhaust gas supply line 8 which leads to the reactor chamber 10. The baffle element 20 can be moved relative to the downstream end 15 of the exhaust gas supply line in order to shut off the exhaust gas supply line 8 at the downstream end 15 or to open it at the downstream end 15. In particular when the baffle element 20 closes the exhaust gas supply line 8 at the downstream end 15, the shut-off device 13 of the bypass line 12 is preferably opened in order to guide the exhaust gas completely through the SCR catalytic converter 9 or the reactor chamber 10 receiving the SCR catalytic converter 9. The shut-off device 13 of the bypass pipe 12 can be completely closed or at least partially opened, in particular when the baffle element 20 opens the downstream end 15 of the exhaust gas supply line 8. In particular when the baffle element 20 opens the downstream end 15 of the exhaust gas supply line 8, the relative position of the baffle element 20 with respect to the downstream end 15 of the exhaust gas supply line 8 depends in particular on the exhaust gas mass flow through the exhaust gas supply line 8 and/or on the exhaust gas temperature of the exhaust gas in the exhaust gas supply line 8 and/or on the amount of reducing agent introduced into the exhaust gas flow via the introduction device 16.

A further function of the baffle element 20 in the case of the open downstream end 15 of the exhaust gas supply line 8 is that any droplets of liquid reducing agent that may be present in the exhaust gas flow reach the baffle element 20 where they are captured and atomized in order to avoid such droplets of liquid reducing agent entering the region of the SCR catalytic converter 9. In the case of the open downstream end 15, the position of the baffle element 20 relative to the downstream end 15 of the exhaust gas supply line 8 makes it possible in particular to determine whether the exhaust gas diverted in the region of the baffle element 20 in the region of the downstream end 15 of the exhaust gas supply line 8 is guided or directed more strongly in the direction of the radially inner-positioned section or in the direction of the radially outer-positioned section of the SCR catalytic converter 9.

On the side 20a facing the exhaust gas supply line 8, the baffle element 20 is curved, preferably bell-curved, while forming a flow guide for the exhaust gases. The side 20a of the baffle element 20 facing the downstream end 15 of the exhaust gas supply line 8 is therefore at a smaller distance from the downstream end 15 of the exhaust gas supply line 8 on the radially inner section of the baffle element 20 than on the radially outer section thereof. The baffle element 20 is thus retracted or bent in the center of the side face 20a in the direction of 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 opens via its downstream end 15 into the reactor chamber 10 which receives the SCR catalytic converter 9. When doing so, the exhaust gas supply line 8 according to fig. 2 penetrates the bottom 22 of the reactor chamber 10 and ends with its downstream end 15 adjacent to the top 23 of the reactor chamber 10, wherein, as already explained, the exhaust gas leaving the exhaust gas supply line at the downstream end 15 is turned through 180 ° before it subsequently flows via the SCT catalytic converter 9.

The exhaust gas aftertreatment system 3 comprises a plurality of gas blowing devices 24, which gas blowing devices 24 are preferably arranged within the reactor chamber 10 in which the SCR catalytic converter 9 is received and are embodied, for example, as air nozzles. In this case, each of the gas blowing devices 24 serves to blow the SCR catalytic converter 9 clean with respect to soot and ash particles deposited on the SCR catalytic converter 9 in order to thereby avoid clogging of the SCR catalytic converter 9. The blowing device 24 is arranged on a common pressure accumulator 25. As shown in fig. 3, the gas blowing device 24 can be arranged not only around the reactor chamber 10, but also below or above the reactor, not shown here. In this case, the diameter of the pressure accumulator ring 25 can be reduced in size, which has the consequence that the overall diameter of the reactor 10 and the pressure accumulator ring 25 is reduced. Here, the pressure accumulator ring 25 can be embodied such that its diameter is not greater than the diameter of the reactor 10, which includes, inter alia, the necessary thermal insulation of the reactor. Because of this, the pressure accumulator ring does not require additional installation space with respect to diameter. The supply 26 to the gas blowing device 24 is then actually effected from the top or from the bottom via the bottom 22 or the top 23 of the reactor shell, in order to avoid an increase in diameter. The pressure accumulator ring 25 is advantageously arranged parallel to the plane formed by the catalytic converter 9.

Fig. 3 shows a preferred orientation of the gas blowing device 24, which gas blowing device 24 is preferably oriented in such a way that a swirling flow or vortex flow is generated in the reactor chamber 10, i.e. on the surface of the SCR catalytic converter 9 extending transversely to the throughflow direction or the exhaust gas flow direction. By means of such a swirling flow or vortex flow, the SCR catalytic converter 9 can be blown clean of soot and ash particles particularly effectively. Fig. 3 shows that the reactor chamber 10, in which the SCR catalytic converter 9 is received, preferably has a wall which is circular in cross section, said wall extending between a bottom 22 and a top 23 of the reactor chamber 10. By means of such a wall 19 in combination with the orientation of the blowing device 24, a swirling flow or vortex flow can be formed particularly advantageously.

The air blowing devices 24 shown in fig. 3 can be supplied with a medium for blowing clean the SCR catalytic converter 9, which originates from a pressure accumulator 25 common to all air blowing devices 24, wherein the pressure accumulator 25 common to all air blowing devices 24 extends in the exemplary embodiment of fig. 3 around the SCR catalytic converter 9 and around the air blowing devices 24 in a circular or annular manner. Here, in the exemplary embodiment shown in fig. 3, the pressure accumulator 25 is positioned outside the reactor chamber 10, so that in fig. 3 the common pressure accumulator 25 therefore also extends circularly or annularly around the reactor chamber 10. However, as already explained by fig. 4, the pressure accumulator 25 may also be positioned above or below the reactor chamber 10, which provides the possibility of reducing the diameter of the pressure accumulator ring 25.

From the common pressure accumulator 25, each of the gas blowing devices 24 can be supplied via a supply line 26 for blowing off the medium of the SCR catalytic converter 9, wherein, in the exemplary embodiment of fig. 3, the respective supply line 26 extends from the common pressure accumulator 25 in the direction of the respective gas blowing device 24 and thus into the reactor chamber 10 and in the process penetrates the wall 19 of the reactor chamber 10.

Although not shown in fig. 3, it is also possible to position the pressure accumulator 25 within the reactor chamber 10 such that the supply line 26 extending from the pressure accumulator 25 to the gas blowing device 24 therefore does not have to penetrate the wall 19 of the reactor chamber 10.

As is apparent from fig. 3, each supply line 26 is assigned a switchable valve 27. Via each switchable valve of the switchable valves 27, each of the air blowing devices 24 can be supplied independently for blowing clean medium of the SCR catalytic converter 9. Here, all gas blowing devices 24 can also be supplied by suitable actuation of the valve 27 for blowing clean the medium of the SCR catalytic converter 9. In contrast to this, it is also possible to open each of the actuatable valves 27 one after the other in a time-sequential timed manner, in order to always supply only one of the blowing devices 24 at a time for blowing clean the medium of the SCR catalytic converter 9.

In the exemplary embodiment shown in fig. 3, the common pressure accumulator 25 is formed as a closed circular pressure accumulator in the form of a circular or ring-shaped pipe, wherein closed means that the pressure accumulator 25 is completely circulating seen in the circulation direction or in the circumferential direction and is therefore not interrupted in the circulation or circumferential direction. The pressure accumulator 25 is thus completely filled, viewed in the direction of circulation or in the circumferential direction, with a medium for blowing clean the SCR catalytic converter 9, which medium can flow freely in the pressure accumulator 25 in the direction of circulation or in the circumferential direction.

Fig. 3 also shows a connection line 28 for a pressure accumulator 25 common to all blowing devices 24, originating from a source for blowing-off the medium of the SCR catalytic converter 9, via which connection line 28 the pressure accumulator 25 can be supplied.

Fig. 4 shows a variant of the exhaust gas aftertreatment system with the SCR catalytic converter 9 positioned in the catalytic converter chamber 10, the wall 19 of said catalytic converter chamber 10 being shaped not as a circle in cross section, but as a polygon, in particular as shown in the exemplary embodiment of fig. 4 as a rectangle. In this case, there are again a plurality of blow-off devices 24 for blowing clean the SCR catalytic converter 9, wherein the blow-off devices 24, which again originate from the common pressure accumulator 25, can be supplied with medium for blowing clean the SCR catalytic converter 9 via a supply line 26 leading to the blow-off devices 24 and branching off from the common pressure accumulator 25, a switchable valve 27 being arranged in the supply line 26. In the exemplary embodiment of fig. 4, just like the wall 29 of the reactor chamber 10, the common pressure accumulator 25 is composed of a polygonal shape, i.e. as a polygonal pipe with a plurality of pipe sections, which extends around the SCR catalytic converter 9 and around the blowing device 24, in particular also around the reactor chamber 10. Here, the gas blowing device 24 in the exemplary embodiment of fig. 4 is not positioned within the reactor chamber 10, but only the injection opening of the gas blowing device 24 opens into the region of the wall 19 of the reactor chamber 10, so that the gas blowing device 24 can blow medium for blowing clean the SCR catalytic converter 9 through the SCR catalytic converter 9.

The length of the supply line 26 is at most 1.5 meters, preferably at most 1 meter, particularly preferably at most 0.5 meter.

By means of the air blowing device 24, the upstream front surface of the SCR catalytic converter 9, seen in the flow direction of the exhaust gas, is blown clean of ash and soot, so that the air blowing direction of the air blowing device 24 therefore extends substantially perpendicularly to the flow direction of the exhaust gas through the SCR catalytic converter 9.

The pressure accumulator 25 shown in fig. 4 is preferably also designed in such a way that it provides a flow conduit closed in the circulation direction around the reactor chamber 10 for blowing clean medium of the SCR catalytic converter 9, which flow conduit is therefore not interrupted at any point, so that the medium can flow or spread freely in the pressure accumulator 25 without obstruction.

Preferred is a configuration of the exhaust gas aftertreatment system in which the pressure accumulator 25 common to the blowing devices 24 has a defined pressure accumulator volume, wherein the following relationship preferably applies to the pressure accumulator volume:

v=k*(273+t)/(273*Δp)

where v is the amount of pressure accumulator volume in litres, where k reaches between 200 and 6000, where t is the amount of temperature of the blowing medium in deg.c, and where Δ p is the amount of pressure difference between the pressure of the pressure accumulator 25 and the pressure of the reactor chamber 10 in bars.

In particular when the pressure accumulator 25 has such a pressure accumulator volume, the blow-off device 24 can particularly preferably be provided for blowing off the medium of the SCR catalytic converter in order to thus effectively remove soot and ash from the SCR catalytic converter 9.

In the case of the combustion engine 1 of fig. 1, the exhaust gas aftertreatment system 3 is positioned vertically above the exhaust gas charging system 2. The cylinders entering the internal combustion engine 1 are free, but the accessibility of the exhaust gas turbochargers 4 and 5 is limited. However, when maintenance operations on the exhaust turbochargers 4, 6 become necessary, the reactor chamber 10 can be easily disassembled.

In contrast to the upright arrangement of the exhaust gas aftertreatment system 3 above the exhaust gas charging system 2 shown in fig. 1, a horizontal arrangement with an inclination of 90 ° of the exhaust gas aftertreatment system 3 immediately adjacent to the exhaust gas charging system 2 is also possible, wherein, however, the length of the arrangement is increased by such a horizontal arrangement. However, the internal combustion engine 1 and the exhaust gas charging system 2 can thus be accessed for maintenance operations without any restrictions, without the need to disassemble the reactor chamber 10.

List of reference numerals:

1 internal combustion engine

2 exhaust gas supercharging system

3 exhaust gas aftertreatment 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 reactor chamber

11 exhaust gas discharge line

12 by-pass pipe

13 shut-off device

14 exhaust gas path

15 end of the tube

16 introducing device

17 spray cone

18 mixing section

19 wall

20 baffle plate element

21 pipeline

Side 22

Side 23

24 air blowing device

25 pressure accumulator

26 supply line

27 valve

28 connecting line

Claims

1. An exhaust gas aftertreatment system (3) of an internal combustion engine,

with an SCR catalytic converter (9) received in a reactor chamber (10),

with an exhaust gas supply line (8) which leads to the reactor chamber (10) and thus to the SCR catalytic converter (9);

with an exhaust gas discharge line (11) leading away from the reactor chamber (10) and thus from the SCR catalytic converter (9);

with an introduction device (16) which is assigned to the exhaust gas supply line (8) for introducing a reducing agent into the exhaust gas,

which is characterized by comprising the following steps of,

a plurality of blow-off devices (24) for blowing off the SCR catalytic converter (9);

a single pressure accumulator (25) common to the gas blowing devices (24), the common single pressure accumulator (25) being formed as a circular or polygonal tube extending closed around the reactor chamber (10) and/or around the gas blowing devices (24), wherein the gas blowing devices (24) can be supplied with a medium for blowing clean the SCR catalytic converter (9) originating from the common pressure accumulator (25),

wherein the blowing direction of the blowing device (24) extends substantially perpendicularly to the exhaust gas flow direction through the SCR catalytic converter, and the blowing device (24) is oriented such that a swirling flow is generated in the reactor chamber (10) on a surface of the SCR catalytic converter (9) extending transversely to the exhaust gas flow direction.

2. The exhaust gas aftertreatment system according to claim 1, characterized in that the common pressure accumulator (25) extends around the reactor chamber (10) outside the reactor chamber (10) or is arranged below or above the reactor chamber (10).

3. Exhaust gas aftertreatment system according to claim 1, characterized in that a supply line (26) from the common pressure accumulator (25) leads to each gas blowing device (24), via which supply line (26) the respective gas blowing device (24) can be supplied for blowing clean the medium of the SCR catalytic converter (9), and each supply line (26) is assigned a switchable valve (27).

4. The exhaust gas aftertreatment system according to claim 2, characterized in that each supply line (26) originating from the pressure accumulator (25) which is located outside the reactor chamber (10) extends through a wall of the reactor chamber (10) up to a respective gas blowing device (24) arranged in the reactor chamber (10), and in that each supply line (26) is assigned a switchable valve (27).

5. The exhaust gas aftertreatment system according to any one of claims 1 to 4, characterized in that the common pressure accumulator (25) extends closed in the circulation direction around the reactor chamber (10) and/or around the gas blowing device (24).

6. The exhaust gas aftertreatment system according to any one of claims 1 to 4, characterized in that the common pressure accumulator (25) is attached to the bottom (22) or top (23) of the reactor chamber (10).

7. Exhaust gas aftertreatment system according to claim 6, characterized in that the supply to the gas blowing device (24) is effected by the bottom (22) or the top (23) of the reactor chamber (10) originating from the common pressure accumulator (25).

8. Exhaust gas aftertreatment system according to any of claims 1-4, characterized in that the common pressure accumulator (25) has a pressure accumulator volume, wherein the following applies:

v=k*(273+t)/(273*Δp)

wherein v is the amount of pressure accumulator volume in litres, wherein k reaches between 200 and 6000, wherein t is the amount of temperature of the blowing medium in degrees celsius, and wherein Δ p is the amount of pressure difference between the pressure of the pressure accumulator (25) and the pressure of the reactor chamber (10) in bars.

9. The exhaust aftertreatment system of claim 1, wherein the reductant is ammonia or an ammonia precursor species.

10. An internal combustion engine with an exhaust gas aftertreatment system (3) according to any one of claims 1 to 9, characterized in that the internal combustion engine comprises a multistage exhaust gas charging system (2), the multistage exhaust gas charging system (2) having 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), wherein the exhaust gas aftertreatment system (3) is connected between the high-pressure turbine (6) and the low-pressure turbine (7).