JP2017190773A - Exhaust gas aftertreatment system, internal combustion engine and operating method for the same - Google Patents

Abstract

A new type of exhaust gas aftertreatment system for an internal combustion engine, an internal combustion engine with an exhaust gas aftertreatment system, and a method for operating such an internal combustion engine. The present invention relates to an SCR exhaust gas aftertreatment system (3) for an internal combustion engine, an SCR catalytic converter (9), an exhaust gas supply line (8) leading to the SCR catalytic converter (9), and an SCR catalytic converter ( 9) an exhaust gas discharge line (11) extending away from the exhaust gas, an introduction device (16) for introducing a reducing agent, in particular ammonia or an ammonia precursor, and an exhaust gas for mixing the reducing agent and the exhaust gas. A reactor section 10 comprising a mixing section (18) provided by a gas supply line (8) and containing an SCR catalytic converter (9) comprises a first wall (24) and a second wall (25); Is formed with a double wall, and a gap through which the heat transfer medium can flow is formed between the first wall and the second wall. [Selection] Figure 2

Description

  The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine. The invention further relates to an internal combustion engine having an exhaust gas aftertreatment system and a method for operating such an internal combustion engine.

  Nitrogen oxides are generated during the combustion process, for example, in an internal combustion engine used in a stationary state at a power plant or in an internal combustion engine used in a non-stationary state, for example in a ship. These nitrogen oxides are typically produced during combustion of sulfur-containing fossil fuels such as coal, wellhead coal, mineral oil, heavy oil or diesel fuel. For this reason, such an internal combustion engine is provided with an exhaust gas aftertreatment system that is useful for cleaning, in particular for denitrification of exhaust gas discharged from the 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 in practice. In the SCR catalytic converter, selective catalytic reduction of nitrogen oxide is performed, and nitrogen oxide ammonia (NH ₃ ) is required as a reducing agent for the reduction. For example, ammonia or ammonia precursor, such as urea, is introduced in liquid form into the exhaust gas upstream of the SCR catalytic converter, and the ammonia or ammonia precursor 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 and the SCR catalytic converter.

  By using an exhaust gas aftertreatment system with a practically known SCR catalytic converter, exhaust gas aftertreatment, in particular nitrogen oxide reduction, has already been successfully carried out. There is a need for further improvements. In particular, there is a need to enable effective exhaust gas aftertreatment through a compact design of such an exhaust gas aftertreatment system and effective operation of an internal combustion engine including the exhaust gas aftertreatment system.

  Starting from this, the present invention aims to create a new type of exhaust gas aftertreatment system for an internal combustion engine, an internal combustion engine comprising an exhaust gas aftertreatment system and a method for operating such an internal combustion engine.

  This object is solved by an exhaust gas aftertreatment system for an internal combustion engine according to claim 1. According to the present invention, the reactor chamber containing the SCR catalytic converter is at least double-walled by a first wall and a second wall arranged on the side of the first wall facing the exhaust gas flow. A gap is formed between the first wall and the second wall, the gap can flow through the heat transfer medium, or the gap can be heated. A transmission medium is distributed. This embodiment of the exhaust gas aftertreatment system enables efficient exhaust gas aftertreatment with a compact design.

  According to an advantageous further development, the circuit for the heat transfer medium comprises an inlet for allowing the heat transfer medium to be introduced into the gap, an outlet for allowing the heat transfer medium to be removed from the gap, and for the heat transfer medium. Including a supply device and a temperature controller for the heat transfer medium. This further development enables efficient exhaust gas aftertreatment with a compact design.

  According to an advantageous further development, the ratio of the thickness of the first wall of the reactor chamber to the thickness of the second wall of the reactor chamber is at least 10: 3, preferably at least 10: 2, particularly preferably At least 10: 1. This further development enables efficient exhaust gas aftertreatment with a compact design.

  According to a further advantageous development, the thickness of the gap between the first wall of the reactor chamber and the second wall of the reactor chamber is at least 2 mm, preferably at least 4 mm, particularly preferably at least 6 mm. is there. This further development enables efficient exhaust gas aftertreatment with a compact design.

  An internal combustion engine according to the invention is defined in claim 7 of the claims. The method of operating an internal combustion engine according to the invention is defined in claim 9 of the claims.

  Particularly preferably, the internal combustion engine comprises a multi-stage exhaust gas supercharging system comprising a first exhaust gas turbocharger comprising a high pressure turbine and a second exhaust gas turbocharger comprising a low pressure turbine. An exhaust gas aftertreatment system is connected between the high pressure turbine and the low pressure turbine.

  Preferred further developments of the invention result from the dependent claims and the following description. Exemplary embodiments of the present invention will be described in more detail with reference to the drawings without being limited thereto.

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.

  The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine, particularly an exhaust gas, such as a stationary internal combustion engine of a power plant or an internal combustion engine not in stationary state used for ships. This aftertreatment system is employed in marine diesel engines operated with heavy oil. Furthermore, the invention relates to an internal combustion engine having such an exhaust gas aftertreatment system and a method for operating the internal combustion engine. FIG. 1 shows a configuration of an internal combustion engine 1 including an exhaust gas supercharging system 2 and an exhaust gas aftertreatment system 3. The internal combustion engine can be an internal combustion engine that is stationary or non-stationary, in particular a ship internal combustion engine that is operated in a non-stationary state. The exhaust gas discharged from the cylinder of the internal combustion engine 1 is used in the exhaust gas supercharging system 2 to extract mechanical energy from the thermal energy of the exhaust gas in order to compress the supply air supplied to the internal combustion engine 1. Is done. Therefore, FIG. 1 shows an exhaust gas supercharging system or an exhaust gas supercharging system 2 including a plurality of exhaust gas turbochargers, that is, a high pressure side first exhaust gas turbocharger 4 and a low pressure side second exhaust gas turbocharger 5. 1 shows an internal combustion engine 1 equipped with The exhaust gas discharged from the cylinder of the internal combustion engine 1 first flows through the high pressure turbine 6 of the first exhaust gas turbocharger 1 and is expanded in the high pressure turbine 6. The energy extracted in this process is used in the high pressure compressor of the first exhaust gas turbocharger 4 for the compression of the supply air. The second turbocharger 5 is disposed downstream of the first exhaust gas turbocharger 4 when viewed in the flow direction of the exhaust gas, and the exhaust gas that has already passed through the high-pressure turbine 6 of the first exhaust gas turbocharger 4. The gas is guided through this second turbocharger 5, ie through the low-pressure turbine 7 of the second exhaust gas turbocharger 5. The exhaust gas is further expanded by the low pressure turbine 7 of the second exhaust gas turbocharger 5 and similarly compressed by the low pressure of the second exhaust gas turbocharger 5 in order to compress the supply air supplied to the cylinders of the internal combustion engine 1. Energy is extracted in the process utilized by the compressor.

  In the case of a single stage turbocharged engine, the structure upstream of one exhaust gas turbine is equally suitable for taking advantage of the higher pressure and temperature levels that exist to favor the reaction.

The internal combustion engine 1 includes, in addition to an exhaust gas supercharging system 2 including two exhaust gas turbochargers 4 and 5, an exhaust gas aftertreatment system 3 that is, for example, an SCR, CH ₄ , HCHO, or oxidized exhaust gas aftertreatment system. Prepare. The exhaust gas aftertreatment system 3 is connected between the high pressure turbine 6 of the first compressor 5 and the low pressure turbine of the second exhaust gas turbocharger 5, so that the exhaust gas exhaust gas is discharged from the high pressure turbine 6 of the exhaust gas turbocharger 4. The exhaust gas thus produced is first guided through the exhaust gas aftertreatment system 3 before the exhaust gas reaches 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 the exhaust gas supply line 8, the exhaust gas can be guided from the high-pressure turbine 6 of the first exhaust gas turbocharger 4 toward the SCR catalytic converter 9 disposed in the reactor chamber 10.

  Further, FIG. 1 shows an exhaust gas discharge line 11 that functions to exhaust the 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 gas starts from the low-pressure turbine 7 and flows through the line 21, in particular through its opening.

  An exhaust gas supply line 8 leading to the reactor chamber 10 and thus the SCR catalytic converter 9 disposed in the reactor chamber 10, and an exhaust gas exhaust line 11 extending away from the reactor chamber 10 and thus the SCR catalytic converter 9 Are connected via a bypass 12 incorporating a blocking element 13. In the state where the blocking element 13 is closed, the bypass 12 is closed, so that the exhaust gas cannot flow through the bypass 12. On the other hand, particularly when the shut-off element 13 is opened, the exhaust gas can flow out via the bypass 12, i.e. the SCR catalytic converter arranged in the reactor chamber 10 and thus in the reactor chamber 10. 9 can be passed.

  In FIG. 2, the flow of exhaust gas through the exhaust gas aftertreatment system 3 with the bypass 12 closed by the blocking element 13 is indicated by the arrow 14. As can be seen from FIG. 2, the exhaust gas supply line 8 opens in the reactor chamber 10 by a downstream end 15, and in the region of this end 15 of the exhaust gas supply line 8, the exhaust gas is The flow is deflected up to about 180 °. The exhaust gas after the flow deflection is guided through the SCR catalytic converter 9.

  An introduction device 16 is provided in the exhaust gas supply line 8 of the exhaust gas aftertreatment system 3. Via the introduction device 16 is introduced into the exhaust gas stream into the reducing agent, in particular ammonia or ammonia precursor, which is necessary for converting the nitrogen oxides of the exhaust gas in the region of the SCR catalytic converter 9 in a defined manner. can do. This introduction device 16 of the exhaust gas aftertreatment system 3 is preferably an injection nozzle that injects ammonia or an ammonia precursor into the exhaust gas flow in the exhaust gas supply line 8. FIG. 2 shows the injection of reducing agent into the exhaust gas stream in the region of the exhaust gas supply line 8 using a cone 17. Of the sections of the exhaust gas aftertreatment system 3, the section disposed downstream of the introduction device 16 and upstream of the SCR catalytic converter as viewed in the flow direction of the exhaust gas is referred to 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 the exhaust gas can be mixed with the reducing agent upstream of the SCR catalytic converter 9.

  The exhaust gas supply line 8 is opened in the reactor chamber 10 by a downstream end 15. A baffle element 19 that can be displaced with respect to the downstream end 15 of the exhaust gas supply line 8 is provided at the downstream end 15 of the exhaust gas supply line 8. In the illustrated exemplary embodiment, the baffle element 19 is linearly movable with respect to the end 15 of the exhaust gas supply line 8 that opens into the reactor chamber 10.

  The baffle element 19 is displaced relative to the downstream end 15 of the exhaust gas supply line 8 in order to shut off the exhaust gas supply line 8 at the downstream end 15 or open the exhaust gas supply line 8 at the downstream end 15. Is possible. In particular, when the baffle element 19 blocks the exhaust gas supply line 8 at the downstream end 15, the blocking element 13 of the bypass 12 is preferentially opened, and the exhaust gas accommodates the SCR catalytic converter 9 or the SCR catalytic converter 9. The reactor chamber 10 is guided completely through.

  Especially when the baffle element 19 is open, the downstream end 15 of the exhaust gas supply line 8 can completely close or at least partially open the blocking element 13 of the bypass 12. In particular, when the baffle element 19 opens the downstream end 15 of the exhaust gas supply line 8, the relative position of the baffle element 19 with respect to the downstream end 15 of the exhaust gas supply line 8 is notably the exhaust gas passing through the exhaust gas supply line 8. Depending on the mass flow rate 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 stream via the introduction device 16.

  A further function of the baffle element 19 with the downstream end 15 of the exhaust gas supply line 8 closed is that the liquid reducing agent droplets present in the exhaust gas stream reach the baffle element 19, where the liquid reducing agent To capture and atomize these droplets to avoid reaching these regions of the SCR catalytic converter 9. Depending on the position of the baffle element 19 relative to the downstream end 15 of the exhaust gas supply line 8 with the downstream end 15 open, deflection in the region at the downstream end 15 of the exhaust gas supply line 8 in the region of the baffle element 19 Whether the exhaust gas directed is concentrated or directed in the direction of the section positioned radially inward or in the direction of the section of the SCR catalytic converter 9 positioned radially outward Can be determined.

  According to a preferred embodiment, the exhaust gas supply line 8 is expanded in the form of a funnel in the region of the downstream end 15 so as to form a diffuser. For this reason, the cross section of the flow of the exhaust gas supply line 8 in the region of the downstream end portion 15 is expanded as is apparent from FIG. The exhaust gas flow cross-section can be initially reduced as viewed in the direction of the 15 upstream exhaust gas flow. Therefore, in FIG. 2, the flow cross section of the exhaust gas supply line 8 seen in the flow direction of the exhaust gas downstream of the introduction device 16 for the reducing agent is initially substantially constant, but gradually tapers, In particular, the increase in the region of the downstream end 15 is shown. Such an expansion of the flow cross section at the downstream end 15 of the exhaust gas supply line 8 in this case is more of the exhaust gas supply line 8 than the section where the exhaust gas supply line 8 is initially tapered upstream of the downstream end 15. Realized preferentially by shorter sections.

  The baffle element 19 is preferentially curved in a curved bell shape on the side surface 20 facing the exhaust gas supply line 8 so as to form a flow guide for the exhaust gas. Thus, as is apparent from FIG. 3, the side surface 20 of the baffle element 19 facing the downstream end 15 of the exhaust gas supply line 8 in the radially inner section of the baffle element 19 is more than in the radially outer section of the baffle element 19. Also has a smaller distance to the downstream end of the exhaust gas supply line 8. In the direction of the downstream end 15 of the exhaust gas supply line 8, the baffle element 19 is drawn in or curved with respect to the flow direction of the exhaust gas at the center of the side surface 20.

  As is clear from FIG. 2 in particular, the exhaust gas supply line 8 and the exhaust gas discharge line 11 are connected to the common first side 22 of the reactor chamber 10 or start from this common side 22. It opens in the reactor chamber 10 or extends into the reactor chamber 10.

  Here, the exhaust gas supply line 8 is connected to the second side 23 of the reactor chamber 10 where the downstream end 15 of the exhaust gas supply line 8 is located on the opposite side of the first side 22 of the reactor chamber 10. It extends into the reactor chamber 10 in an adjacently arranged manner. In contrast, the exhaust gas discharge line 11 opens into the reactor chamber 10 at the first side 22. Therefore, the exhaust gas supplied through the exhaust gas supply line 8 is about 180 in the region of the second side 23 of the reactor chamber 10 that is disposed opposite the downstream end 15 of the exhaust gas supply line 8. Deflected and subsequently flows through the SCR catalytic converter 9 and then flows through the first side 22 towards the region of the exhaust gas discharge line 11. As can be seen from FIG. 2, the exhaust gas discharge line 11 adjacent to the side 22 of the reactor chamber 10 is preferentially concentric in the specific section outside the reactor chamber 10. Siege 8

  In order to enable a particularly efficient operation of the internal combustion engine 1 including a particularly efficient exhaust gas aftertreatment and an exhaust gas aftertreatment system 3, the reactor chamber 10 containing the SCR catalytic converter 9 is at least double-walled. In other words, it is formed in at least a specific section in the region of the wall 32 of the reactor chamber 10 arranged between the two sides 22, 23.

  This ensures that the thermal energy of the exhaust gas remains in the exhaust gas and is not released excessively to the walls of the reactor chamber 10. The high temperature of the exhaust gas is advantageous for effective exhaust gas aftertreatment in the region of the SCR catalytic converter 9, while the effective of the exhaust gas turbocharger arranged downstream of the exhaust gas aftertreatment device 3. It is also advantageous for operation.

  The exhaust gas supply line 8 and / or the exhaust gas discharge line 11 may be formed of at least a double wall.

  A high exhaust gas temperature in the region of the SCR catalytic converter 9 is advantageous in order to avoid the formation of undesirable secondary reactions of the reducing agent, in particular ammonia sulfate and / or ammonium bisulfate. These undesirable by-products that can be generated at exhaust gas temperatures that are too low can damage the SCR catalytic converter 9 and thus the effectiveness of exhaust gas aftertreatment.

  Further, as described above, the high exhaust gas temperature of the exhaust gas aftertreatment device 3 is that the efficiency of the exhaust gas turbocharger disposed downstream as viewed in the flow direction of the exhaust gas aftertreatment device 3, particularly the low pressure turbine thereof, is improved. It is advantageous to operate automatically.

  The reactor chamber 10 containing the SCR catalytic converter 9 has at least a first wall 24 in the region of the wall 32 and a second wall on the side of the first wall 24 facing the exhaust gas flow (not shown). 25. A gap 26 through which a heat transfer medium flows is formed between the first wall 24 and the second wall 25 of the reactor chamber 10 that houses the SCR catalytic converter 9.

  The first wall 24 of the reactor chamber 10 is designed such that the first wall has a thickness designed for maximum pressure in a manner that withstands the maximum pressure. The maximum pressure is 4 bar at the maximum.

  The second wall 25 has a thickness that is less than the thickness of the first wall 24. The thickness of the first wall is indicated by d1 in FIG. 3, and the thickness of the second wall 25 is indicated by d2. The dimension of the gap 26 formed between the first wall 25 and the second wall 25 is indicated by l21.

  According to an advantageous further development, the ratio between the thickness d1 of the first wall 24 of the reactor chamber 10 and the thickness d2 of the second wall 25 of the reactor chamber 10 is at least 10: 3, Preferably it is at least 10: 2, particularly preferably at least 10: 1.

  The dimension of the air gap l12 between the first wall 24 of the reactor chamber 10 and the second wall 25 of the reactor chamber 10 is at least 2 mm, preferably at least 4 mm, particularly preferably at least 6 mm.

  The product of the mass of the first wall 24 of the reactor chamber 10 and the heat capacity is preferentially greater than the corresponding product of the mass of the second wall 27 of the reactor chamber 10 and the heat capacity.

  Both the first wall 24 of the reactor chamber 10 and the second wall 25 of the reactor chamber 10 can be made from a metallic material, such as steel. A configuration in which the first wall 24 is manufactured from a metal material and the second wall 25 is manufactured from a ceramic material is preferred. Similarly, the first wall 24 and the second wall 25 can each be made of a metal material, the second wall 25 having a ceramic coating preferentially on the side facing the exhaust gas flow. May be.

  With respect to the present invention, a heat transfer medium can flow or a heat transfer medium can flow through a gap 26 formed between the first wall 24 of the reactor chamber 10 and the second wall 25 of the reactor chamber 10. . Thus, the reactor chamber 10 may be brought to a predetermined temperature so as to ensure optimum exhaust gas aftertreatment, particularly in that the SCR catalytic converter 9 is continuously operated at the optimum operating temperature.

  For this purpose, the exhaust gas aftertreatment system 3 comprises a circuit 27 for the heat transfer medium. This circuit 27 comprises an inlet 28 allowing the heat transfer medium to be introduced into the gap 26, an outlet 29 allowing the heat transfer medium to be discharged from the gap 26, a supply device 30 for the heat transfer medium, and the heat transfer medium A temperature control device 31.

  By means of the inlet 28, the heat transfer medium brought to a defined set temperature in the temperature control device 31 can be introduced into the gap 26 formed between the walls 24 and 25 of the reactor chamber 10, so that the heat The transmission medium can flow through the gap 26, so that the reactor chamber 10 can be temperature controlled, especially through the wall 25. The heat transfer medium flowing through the gap 26 can be extracted from the gap 26 via the outlet 29 with the aid of the supply device 30, and then in connection with the closed circuit the temperature to induce the heat transfer medium. It is supplied again via the control device 31.

  The heat transfer medium can be a gas, in particular air, or a fluid, for example water. As described above, in order to enable optimum exhaust gas aftertreatment at the optimum operating temperature in the region of the SCR catalytic converter 9 located in the reactor chamber 10, the reactor chamber 10 is made up with a heat transfer medium. Can be brought to a predetermined temperature.

  The heat transfer medium does not come into contact with the exhaust gas. Therefore, the supply device 30 and the temperature control device 31 do not come into contact with corrosive gas. The supply device 30 is in particular a pump or a blower. The temperature control device 31 is preferentially a heat exchanger or another heating device.

  The invention further relates to a method for operating an internal combustion engine having such an exhaust gas aftertreatment system 3. In the method according to the invention, the reactor chamber 10 transfers heat through a gap 26 between the first wall 24 and the second wall 24 of the reactor chamber 10 depending on the operating conditions of the internal combustion engine 1. The temperature is automatically controlled via the medium.

  In this connection, for example when the internal combustion engine is operated in a cold start mode of operation, the reactor chamber 10 is connected via a heat transfer medium flowing through the gap 26 prior to the actual start of the internal combustion engine. Heat to set temperature.

  Similarly, it is possible to detect the temperature in the reactor chamber 10 with the aid of a temperature sensor, especially when the temperature in the reactor chamber 10 is below a limit value, and the heat transfer flowing through the gap 26 The reactor chamber 10 can also be heated to a set temperature via the medium.

  As described above, not only the reactor chamber 10 can be realized with a double wall, but also the exhaust gas supply line 8 and / or the exhaust gas discharge line 11 of the exhaust gas aftertreatment system 3 can be realized with a double wall.

  Even in the region of the exhaust gas supply line 8 and / or the exhaust gas discharge line 11, in order to affect the exhaust gas in the exhaust gas supply line 8 and / or the exhaust gas discharge line 11, the heat transfer medium is applied in the manner described above. Gaps that can be guided can be formed between the corresponding walls. The bypass 12 can likewise be implemented with a double wall.

  In the internal combustion engine 1 of FIG. 1, the exhaust gas aftertreatment device 3 is arranged in an upright state above the exhaust gas supercharging system 2. Access to the cylinders of the internal combustion engine 1 is open, but the accessibility of the exhaust gas turbochargers 4, 5 is limited. When maintenance work is required for the exhaust gas turbochargers 4 and 5, the reactor chamber 10 may be easily disassembled.

  In contrast to the configuration of the exhaust gas aftertreatment system 3 above the exhaust gas supercharging system 2 shown in FIG. 1, as shown in FIG. 1, after the exhaust gas adjacent to the exhaust gas supercharging system 2 inclined by 90 ° A horizontal arrangement of the processing system 3 is possible, but when such a horizontal arrangement is used, the length of the arrangement becomes large. The internal combustion engine 1 and the exhaust gas supercharging system 2 can be used without the need for disassembling the reactor chamber 10 and without any restrictions for maintenance work.

Exemplary embodiments of the present invention are directed to SCR technology, yet the present invention is not so limited and can be used in particular with gas engines or with CH ₄ and HCHO oxidation catalytic converters. In the case of a single-stage supercharged engine, it is advantageous to arrange the exhaust gas aftertreatment system upstream of the turbine.

DESCRIPTION OF SYMBOLS 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 Bypass 13 Blocking element 14 Exhaust gas path 15 End 16 Introducing device 17 Injection cone 18 Mixing section 19 Baffle element 20 Side surface 21 Line 22 Side portion 23 Side portion 24 First wall 25 Second wall 26 Gap 27 Circuit 28 Inlet 29 Outlet 30 Supply device 31 Temperature control device 32 Wall

Claims (12)

For example, an exhaust gas aftertreatment system (3) for an internal combustion engine, which is an SCR exhaust gas aftertreatment system,
A catalytic converter (9); an exhaust gas supply line (8) leading to the catalytic converter (9); and an exhaust gas discharge line (11) extending away from the catalytic converter (9). ,
A reactor chamber (10) containing the catalytic converter (9) has a first wall (24) and a second wall (25) arranged on the side of the first wall facing the exhaust gas flow. ) And at least a double wall, and
An exhaust gas aftertreatment system, wherein a heat transfer medium can flow through a gap (26) formed between the first wall (24) and the second wall (25).   An inlet (28) for allowing the circuit (27) for the heat transfer medium to introduce the heat transfer medium into the gap (26) and an outlet allowing the heat transfer medium to be discharged from the gap (26) The exhaust gas post of claim 1, comprising: (29), a supply device (30) for the heat transfer medium, and a temperature control device (31) for the heat transfer medium. Processing system.   The first or second wall (24) of the reactor chamber (10) is thicker than the second wall (25) of the reactor chamber (10). The exhaust gas aftertreatment system described.   The ratio of the thickness of the first wall (24) of the reactor chamber (10) to the thickness of the second wall (25) of the reactor chamber (10) is at least 10: 3, preferably at least 4. The exhaust gas aftertreatment system according to claim 3, characterized in that it is 10: 2, particularly preferably at least 10: 1.   The exhaust gas aftertreatment system according to any one of claims 1 to 4, wherein the product of the mass and heat capacity of the first wall is larger than the corresponding product of the second wall.   The thickness of the gap (26) between the first wall (24) of the reactor chamber (10) and the second wall (25) of the reactor chamber (10) is at least 2 mm; 6. The exhaust gas aftertreatment system according to claim 1, wherein the exhaust gas aftertreatment system is preferably at least 4 mm, particularly preferably at least 6 mm.   An internal combustion engine (1), in particular an internal combustion engine operated with diesel fuel or heavy oil fuel, comprising the exhaust gas aftertreatment system (3) according to any one of claims 1 to 6.   8. The internal combustion engine of claim 7, wherein the internal combustion engine is supercharged with exhaust gas and the reactor chamber is disposed upstream of at least one exhaust gas turbocharger. The internal combustion engine includes a first exhaust gas turbocharger (4) including a high pressure turbine (6) and a second exhaust gas turbocharger (5) including a low pressure turbine (7). 2)
The internal combustion engine according to claim 7 or 8, wherein the exhaust gas aftertreatment system (3) is connected between the high pressure turbine (6) and the low pressure turbine (7). A method for operating an internal combustion engine according to any one of claims 7 to 9, comprising:
The reactor chamber (10) flows through the gap (26) between the first wall (24) and the second wall (25) depending on the operating conditions of the internal combustion engine (1). A method characterized in that the temperature is controlled via a heat transfer medium.   Especially when the temperature of the reactor chamber (10) is lower than a limit value, the reactor chamber (10) is heated to a set temperature via a heat transfer medium flowing through the gap (26). 11. A method according to claim 10, characterized in that   Particularly when the internal combustion engine is operated in a cold start mode of operation, the reactor chamber (10) is heated to a set temperature via a heat transfer medium flowing through the gap (26). 12. A method according to claim 10 or claim 11.