Exhaust manifold with double housing, internal combustion engine with such an exhaust manifold and method for operating such an internal combustion engine

Abstract

Exhaust manifold (28) for an internal combustion engine (10), which forms at least one inlet channel section (36) for connection to at least one outlet channel (38) assigned to a combustion chamber (14) of an internal combustion engine (12) of the internal combustion engine (10), and an outlet channel section (42) for connection to a further section of an exhaust system of the internal combustion engine (10), wherein the exhaust manifold (28) is delimited on the outside by an outer housing (44) and wherein an inner housing (46) is provided which runs at a distance from at least a section of the outer housing (44), whereby a gap channel (52) leading from the inlet channel section (36) in the direction of the outlet channel section (42) is formed, which gap channel can be closed if necessary by means of a closure device (54), characterized in that the inner housing (46) is longer than the outer housing (44) at a free end of the inlet channel section (36).

Description

[0001] The invention relates to an exhaust manifold and an internal combustion engine having an exhaust manifold. The invention further relates to a method for operating an internal combustion engine.

[0002] An exhaust manifold represents the first section of an internal combustion engine's exhaust system, or the section directly adjoining the exhaust ports of an internal combustion engine. In a multi-cylinder internal combustion engine, an exhaust manifold also serves to collect the exhaust gas flowing out of several exhaust ports and to feed it to a subsequent section of the exhaust system, for example an exhaust gas aftertreatment device or the turbine of an exhaust gas turbocharger.

[0003] Such an exhaust manifold can be subject to contradictory requirements regarding its thermal performance. During a warm-up phase following a cold start of the associated internal combustion engine, and possibly also during operation of the internal combustion engine at low loads, the exhaust gas should cool as little as possible as it flows through the exhaust manifold in order to reach downstream components of the exhaust system, and in particular one or more exhaust gas aftertreatment devices, at the highest possible temperature. This ensures that their operating temperatures reach the limits required for effective exhaust gas aftertreatment as quickly as possible or that these limits are not undercut during continuous operation of the internal combustion engine at low loads. In this case, the best possible thermal insulation effect of the exhaust system is therefore advantageous.On the other hand, during prolonged operation of the internal combustion engine at high loads, and especially at maximum load, there is a risk of thermal overload of components integrated into the exhaust system, in particular one or more exhaust aftertreatment devices and / or the turbine of an exhaust gas turbocharger, which can damage them and / or adversely affect their functions. In this case, appropriate cooling of the exhaust gas as it flows through the exhaust manifold is therefore advantageous.

[0004] DE 10 2010 018 087 A1 discloses an exhaust system for an internal combustion engine with multiple combustion chambers. Provision is made for separate exhaust gas discharge via two exhaust ducts per combustion chamber of an internal combustion engine of the internal combustion engine and two exhaust manifolds, each of which is connected to one of the exhaust ducts. The two exhaust manifolds are integrated into one another in such a way that a manifold of an outer exhaust manifold surrounds a manifold of an inner exhaust manifold, forming a gap. If the internal combustion engine has an operating temperature still below a limit value and / or is operated at a relatively low load, the resulting exhaust gas should be discharged from the combustion chambers only through the exhaust ducts connected to the inner exhaust manifold and thus only flow through the inner exhaust manifold.The gas-filled gap formed between the manifolds of the inner and outer exhaust manifolds provides thermal insulation, so that the exhaust gas flowing through the inner exhaust manifold cools only slightly. In other operating states of the internal combustion engine, however, the exhaust gas is routed through both exhaust manifolds. Additional thermal insulation should preferably be provided for the manifold of the outer exhaust manifold.

[0005] A disadvantage of the exhaust system known from DE 10 2010 018 087 A1 is that, in order to achieve thermal insulation for the exhaust gas flowing exclusively through the inner exhaust manifold, the exhaust gas must be supplied exclusively via the exhaust ports of the combustion chambers assigned to it. This not only limits the flow volume of the exhaust system available for this operating state, but also requires the other exhaust ports of the combustion chambers connected to the outer exhaust manifold to be kept closed, which can be achieved by means of a corresponding variable valve train. However, such a variable valve train involves considerable design effort. Furthermore, the thermal insulation of the outer exhaust manifold prevents relevant cooling of the exhaust gas when the internal combustion engine is operating at high loads.The contradictory requirements for an exhaust manifold mentioned at the beginning are therefore not solved by an exhaust system according to DE 10 2010 018 087 A1.

[0006] DE 10 2008 014 435 A1 discloses a section of an exhaust system located upstream of an exhaust aftertreatment device and having a double-walled design. If necessary, exhaust gas can also be guided through the outer annular channel to specifically cool the exhaust gas supplied to the exhaust aftertreatment device. The routing of exhaust gas through the annular channel is controlled by means of closure elements arranged on the inlet or outlet side.

[0007] DE 102 06 066 A1 and DE 101 33 422 A1 each disclose double-walled sections of exhaust gas tracts, wherein air can be guided through the respective outer annular gaps for cooling purposes.

[0008] DE 102 30 918 A1 discloses an exhaust manifold for an internal combustion engine, which forms at least one inlet channel section for connection to at least one outlet channel assigned to a combustion chamber of an internal combustion engine of the internal combustion engine and an outlet channel section for connection to a further section of an exhaust system of the internal combustion engine, wherein the exhaust manifold is delimited on the outside by an outer housing and wherein an inner housing is provided which runs at a distance from at least a section of the outer housing, whereby a gap channel is formed which leads from the inlet channel section in the direction of the outlet channel section and which can be closed if necessary by means of a closure device.

[0009] The object of the invention was to provide an exhaust manifold in which, despite the simplest possible design, the actually contradictory requirements for thermal behavior can be advantageously met.

[0010] This object is achieved by means of an exhaust manifold according to patent claim 1. An internal combustion engine with such an exhaust manifold and a method for operating such an internal combustion engine are the subject matter of patent claims 7 and 8. Advantageous embodiments of the exhaust manifold according to the invention and the internal combustion engine according to the invention as well as preferred embodiments of the method according to the invention are the subject matter of the further patent claims and / or emerge from the following description of the invention.

[0011] According to the invention, an exhaust manifold for an internal combustion engine is provided. This comprises at least one inlet channel section, which is provided for a fluid-conducting connection to at least one outlet channel assigned to a combustion chamber of an internal combustion engine of the internal combustion engine. An exhaust manifold according to the invention further forms at least one, preferably a single outlet channel section, which is provided for connection to a further section of an exhaust system of the internal combustion engine, or to a section located downstream of the exhaust manifold. This further section of the exhaust system can already be a turbine of an exhaust gas turbocharger or an exhaust gas aftertreatment device.

[0012] If the exhaust manifold is intended for use with an internal combustion engine having a plurality of combustion chambers, it can preferably be provided that the exhaust manifold comprises at least one inlet channel section for each of the combustion chambers, which inlet channel section is provided for a fluid-conducting connection to the outlet channel(s) of the individual combustion chambers. Accordingly, a plurality of inlet channel sections can be provided, which are provided for a connection to outlet channels assigned to one or more combustion chambers of the internal combustion engine, wherein the inlet channel sections merge into a collecting channel section of the exhaust manifold and the collecting channel section merges into the outlet channel section. The exhaust manifold can therefore also fulfill the functions of a collecting device for the exhaust gas flowing over from a plurality of exhaust channels of the internal combustion engine in the usual way.The multiple exhaust ports can also be assigned to only one combustion chamber of the internal combustion engine.

[0013] An exhaust manifold according to the invention is further delimited on the outside by an outer housing that is preferably not thermally insulated and thus has as little insulating effect as possible. It also comprises an inner housing that runs at a distance from the outer housing in at least one section (of the outer housing). A gap channel is formed that leads from the inlet channel section toward the outlet channel section and preferably up to or into the outlet channel section and can be closed as needed by means of a closure device. By means of the closure device, the proportion of exhaust gas overflowing from the exhaust channel(s) of the internal combustion engine, which subsequently flows through the gap channel, can be influenced and, in particular, reduced to zero as needed.

[0014] An exhaust manifold according to the invention is further characterized in that the inner housing is longer than the outer housing at the free end of the inlet channel section or of one, several, or each of the inlet channel sections, allowing the outer housing to extend a short distance into the (respectively) associated exhaust channel of the internal combustion engine. This can have an advantageous effect on the flow guidance of the exhaust gas as it flows from the exhaust channel or channels of the internal combustion engine into the inlet channel section or sections of the exhaust manifold.

[0015] An internal combustion engine according to the invention comprises at least one internal combustion engine and one exhaust manifold according to the invention. The inlet channel section(s) of the exhaust manifold are connected to one or more outlet channels of the internal combustion engine in a fluid- or exhaust-conducting manner. In particular, it can be provided that the outer housing is firmly connected, for example, screwed, to a housing and in particular to a cylinder head housing of the internal combustion engine. For the inner housing, however, it can be provided that there is no direct contact with the internal combustion engine or that the inner housing is positioned contactlessly with respect to the internal combustion engine.

[0016] An internal combustion engine according to the invention can further comprise a section of an exhaust system adjoining the exhaust manifold, which also includes the exhaust manifold. One or more functional components, in particular a turbine of an exhaust gas turbocharger and / or one or more exhaust gas aftertreatment devices, can preferably be integrated into this section of the exhaust system. One of these functional components can preferably be directly connected to the outlet channel section of the exhaust manifold.

[0017] The gap channel of an exhaust manifold according to the invention formed between the outer housing and the inner housing, as well as a central channel delimited by the inner housing, run from the inlet channel section(s) (each) in fluid communication with an exhaust channel of the internal combustion engine in the direction of the outlet channel section of the exhaust manifold, so that consequently the entire exhaust gas guided via the exhaust channel(s) of the internal combustion engine can be guided, if necessary - and controlled by means of the closure device belonging to the exhaust manifold - only via the central channel or also via the gap channel.Consequently, there is no need, in accordance with the design of an exhaust system as known from DE 10 2010 018 087 A1, to provide at least two exhaust ports per combustion chamber and, moreover, to enable at least one of these exhaust ports to be kept closed during operation of the internal combustion engine, provided that a thermal insulation effect for the exhaust gas is to be achieved by guiding its flow via a central port or the inner exhaust manifold in the exhaust system according to DE 10 2010 018 087 A1. Rather, a relatively simply designed closure device can be provided, the effect of which can relate only to the gap port and, in particular, to a single-flow section thereof. This applies in particular if, as is preferably provided, the closure device is arranged on the outlet side of the gap port.

[0018] Consequently, an operation of an internal combustion engine according to the invention can be advantageously realized, characterized in that, for operation of the internal combustion engine with a value of at least one operating parameter below a possibly variable limit value, the closure device is brought into an at least partially and preferably completely closing position. As a result, a large portion or all of the exhaust gas discharged from the internal combustion engine flows through the central channel delimited on the inside by the inner housing, so that a thermal insulation effect is then realized for this exhaust gas flow through the gap channel through which no or hardly any flow passes.This can be provided, in particular, during a warm-up phase of the internal combustion engine, particularly after a cold start, which can extend until a lower limit of a defined operating temperature range for the internal combustion engine is reached, and / or during operation of the internal combustion engine with relatively low loads, whereby cooling of the exhaust gas as it flows through the exhaust manifold can be kept as low as possible. Consequently, the fastest possible heating of one or more functional components integrated into the exhaust system of an internal combustion engine according to the invention, in particular exhaust gas aftertreatment device(s), can be achieved and / or excessive cooling of these functional components can be prevented.

[0019] On the other hand, it can be provided that for operation of an internal combustion engine according to the invention with a value of a (different or the same) operating parameter above a (different or the same) limit value, the closure device is moved to the widest possible open position. In this case, a relevant portion of the exhaust gas discharged from the internal combustion engine is also guided via the gap channel, thereby achieving relevant cooling of the exhaust gas, which can prevent thermal overload of one or more functional components integrated into the exhaust system, particularly during prolonged operation of the internal combustion engine at relatively high loads.Another advantage is that by using both the central channel formed by the inner housing and the gap channel formed between the inner and outer housing, a relatively large flow volume is available for the flow guidance of the exhaust gas flow, which is relatively large when the internal combustion engine is operating at high loads, whereby the exhaust gas back pressure resulting from the flow through the exhaust system can be kept relatively low.

[0020] The operating parameter(s) may in particular be the load and / or the speed at which the internal combustion engine is operated and / or a body and / or fluid temperature of a component of the internal combustion engine.

[0021] To enable automated implementation of a method according to the invention, an internal combustion engine according to the invention can preferably have a control device configured to appropriately control the closure device. The control device can, in particular, be a central engine control unit of the internal combustion engine.

[0022] A structurally advantageous embodiment of a closure device for an exhaust manifold according to the invention can be characterized in that the closure device is designed as a rotating diaphragm or at least comprises such a diaphragm. This consequently has a first diaphragm ring and a second diaphragm ring, which are arranged axially adjacent and rotatable to one another and each form at least one and preferably a plurality of through-openings, wherein the through-openings of the diaphragm rings can be brought into a variable overlap by means of an adjusting device. In particular, the greatest possible overlap can be adjustable, thereby achieving the greatest possible exposure of the gap channel. Furthermore, a non-existent overlap of the through-openings can be adjustable, whereby the gap channel is essentially completely closed.

[0023] An advantageous flow guidance for the exhaust gas in an exhaust manifold according to the invention can be achieved by having the inner housing run completely parallel to the adjacent sections of the outer housing. The inner housing can therefore correspond in shape to the outer housing or the adjacent section thereof, merely having smaller dimensions or scaling.

[0024] A preferably immovable positioning of the inner housing within the outer housing can advantageously be achieved by connecting the inner housing to the outer housing by means of one or more connecting elements. The unit comprising the inner housing, outer housing and connecting element(s) can, if appropriate, be designed as a single piece and, in particular, from the same material. For example, a single-piece design of this unit in the form of a cast component made of a metal, in particular a light metal (e.g., aluminum), is advantageously conceivable. Such a unit comprising the inner housing, outer housing and connecting element(s) can also advantageously be manufactured using a generative manufacturing process. Production from plastic(s) is also conceivable.

[0025] The invention also relates to a motor vehicle, in particular a non-rail-bound, wheel-based motor vehicle (preferably a car or truck), with an internal combustion engine according to the invention. The internal combustion engine of the internal combustion engine can be provided, in particular, for the (direct or indirect) provision of drive power for the motor vehicle.

[0026] The indefinite articles ("a", "an", "one", and "another"), particularly in the patent claims and in the description generally explaining the patent claims, are to be understood as such and not as numerals. Components specified accordingly are thus to be understood as being present at least once and may be present multiple times.

[0027] The invention is explained in more detail below with reference to an exemplary embodiment illustrated in the drawings. The drawings show, in simplified form: Fig. 1: a motor vehicle according to the invention; Fig. 2: an internal combustion engine according to the invention; Fig. 3: in more detail the internal combustion engine and the exhaust manifold of the internal combustion engine according to the Fig. 2 in a first operating state of the internal combustion engine; Fig. 4: a front view of an inlet channel section of the exhaust manifold according to the Fig. 3; Fig. 5: a front view of the exhaust manifold closure device according to the Fig. 3; Fig. 6: a more detailed representation of the internal combustion engine and the exhaust manifold of the internal combustion engine according to the Fig. 2 in a second operating state of the internal combustion engine; Fig. 7: a front view of the exhaust manifold closure device according to the Fig. 6;

[0028] The Fig. 1 shows a motor vehicle according to the invention with an internal combustion engine 10 according to the invention.

[0029] Such an internal combustion engine 10 can be Fig. 2 may comprise an internal combustion engine 12, for example a gasoline or diesel engine, which forms a plurality of cylinders. The cylinders, together with pistons guided up and down therein and a cylinder head, define combustion chambers 14 in which fresh gas (mainly air) is combusted together with fuel, causing the pistons to move up and down cyclically. These piston movements are transmitted in a known manner to a crankshaft (not shown), which thus drives the crankshaft in rotation.

[0030] The fresh gas is supplied to the combustion engine 12 via a fresh gas line and is drawn in from the environment via an intake port 16, cleaned in an air filter 18, and then fed to a compressor 20, which is part of an exhaust gas turbocharger. The fresh gas is compressed by the compressor 20, then optionally cooled in a charge air cooler 22, and fed to the combustion chambers 14, optionally controlled by a throttle valve 24.

[0031] The compressor 20 is driven by a turbine 26, which is integrated into an exhaust system of the internal combustion engine 10 and is also part of the exhaust gas turbocharger. Exhaust gas produced during the combustion of fuel-fresh gas mixtures in the combustion chambers 14 of the internal combustion engine 10 is discharged from the internal combustion engine 12 via the exhaust system and is initially collected or combined in an exhaust manifold 28. The exhaust gas then flows through a first exhaust gas aftertreatment device 30, for example in the form of a 3-way catalytic converter or an SCR catalytic converter, then through the turbine 26, and then through a second exhaust gas aftertreatment device 32, for example in the form of a particulate filter, before the exhaust gas flows through a silencer (not shown) and is released into the environment.

[0032] The flow through the turbine 26 leads in a known manner to a rotating drive of a turbine impeller, which in turn is connected in a rotationally fixed manner to a compressor impeller of the compressor 20 via a shaft 34.

[0033] The Fig. 3 and Fig. 6 show the internal combustion engine 12 and the exhaust manifold 28 of the internal combustion engine 10 according to the Fig. 2 in somewhat more detailed representations. Accordingly, the exhaust manifold 28 forms a plurality of inlet channel sections 36, each of which is assigned to one of the combustion chambers 14 of the internal combustion engine 12 and, for this purpose, is fluidly connected to a respective exhaust channel 38 of the internal combustion engine 12. The exhaust channels 38 are formed within the cylinder head of the internal combustion engine 12 and represent a fluid-conducting connection between the combustion chambers 14 and the respectively associated inlet channel sections 36 of the exhaust manifold 28. An overflow of exhaust gas from the combustion chambers 14 into the associated exhaust channels 38 can take place in a known manner by means of exhaust valves (not shown), which can be actuated via a valve train of any design.

[0034] The inlet channel sections 36 merge into a collecting channel section 40 of the exhaust manifold 28, and the collecting channel section 40 merges into a single outlet channel section 42 of the exhaust manifold 28. The exhaust gas flowing through the individual inlet channel sections 36 is collected by means of the collecting channel section 40 and subsequently discharged into the subsequent part of the exhaust system via the outlet channel section 42.

[0035] The exhaust manifold 28 comprises an outer housing 44 and an inner housing 46, which is arranged in the region of the inlet channel sections 36 and the collecting channel section 40 within the outer housing 44. The housing shape of the inner housing 46 corresponds to the housing shape of the sections of the outer housing 44 adjacent to the inner housing 46, with the exception of a smaller scaling, resulting in a parallel or uniformly spaced course between the housing walls. The immovable positioning of the inner housing 46 within the outer housing 44 is realized by means of strut-shaped connecting elements 48 (see. Fig. 4). On the inside, the inner housing 46 forms a central channel 50, which is designed to be multi-flow in the region of the inlet channel sections 36 of the exhaust manifold 28. Between the inner housing 46 and the outer housing 44, a gap channel 52 is also formed, which is also designed to be multi-flow in the region of the inlet channel sections 36 and to be single-flow at the end, i.e., in the region of the transition between the collecting channel section 40 and the outlet channel section 42 of the exhaust manifold 28. A closure device 54 is arranged at the end of the gap channel 52, by means of which, controlled by a control device (not shown), the gap channel 52 can be closed as required, so that a flow of exhaust gas through the gap channel 52 is more or less prevented.

[0036] As can be seen in particular from the Fig. 5 and Fig. 7, the shutter device 54 is designed in the form of a rotating diaphragm, which comprises a first, fixed diaphragm ring 58 and a second diaphragm ring 58 arranged axially adjacent to the first diaphragm ring 56 and rotatably mounted. The second diaphragm ring 58 is rotatable by means of an adjusting device (not shown), whereby by such rotation, through openings 60 in the two diaphragm rings 56, 58 can be positioned with more or less overlap or without overlap. Fig. 5 shows that the through-openings 60 in the two aperture rings 56, 58 do not overlap each other, whereby closure sections 62, 64 of the aperture rings 46, 48 form a completely closed ring through which the gap channel 52 of the exhaust manifold 28 of the Fig. 3 is completely closed. The Fig. 7, however, shows a complete overlap of the through openings 60 (as well as the closure sections 62, 64) of the aperture rings 56, 58, whereby the widest possible release of the gap channel 52 according to the Fig. 6 is realized.

[0037] The operating state of the internal combustion engine 10 according to the Fig. 3 or the locking position of the locking device according to the Fig. 5 is provided when the internal combustion engine 12 is operating at relatively low loads and / or at a still relatively low operating temperature. As a result of the complete closure of the gap channel 52 by means of the closure device 54, all of the exhaust gas passing from the combustion chambers 14 via the outlet channels 38 into the exhaust manifold 28 flows through the central channel 50 delimited by the inner housing 46. The gap channel 52, in contrast, is filled with static exhaust gas. Due to a relatively poor heat transfer coefficient, this exhaust gas located in the gap channel 52 has an insulating effect on the exhaust gas flowing through the central channel 52, as a result of which the exhaust gas cools only slightly as it flows through the exhaust manifold 28.This has an advantageous effect in terms of reaching or maintaining an operating temperature range for the components integrated into the exhaust system downstream of the exhaust manifold 28, in particular the exhaust aftertreatment devices 30, 32, as quickly as possible.

[0038] The operating state of the internal combustion engine 10 according to the Fig. 6 or the locking position of the locking device according to the Fig.7, however, is provided when the internal combustion engine 12 is operating at relatively high loads. As a result of the gap channel 52 being opened as far as possible by means of the closure device 54, a relevant portion of the exhaust gas passing from the combustion chambers 14 via the outlet channels 38 into the exhaust manifold 28 flows through the gap channel 52. This portion of the exhaust gas is separated from the environment only by the thinnest possible (as far as structurally possible) metallic housing wall of the outer housing 44. Due to the relatively high heat transfer coefficient of the material of this housing wall and also the thinnest possible (as far as structurally possible) housing wall of the inner housing 46, which is also made of metal, the exhaust gas flowing through the exhaust manifold 28 is cooled relatively intensively as a result of the transfer of thermal energy to the ambient air.This prevents thermal overload of the components integrated into the exhaust system downstream of the exhaust manifold 28. Furthermore, in this operating state of the internal combustion engine 10, the entire internal volume of the exhaust manifold 28 is used to guide the exhaust gas flow, which has a positive effect on minimizing the backpressure caused by the relatively large exhaust gas flow in this operating state. LIST OF REFERENCE SYMBOLS 10 internal combustion engine 12 internal combustion engine 14 Combustion chamber 16 Intake port 18 air filters 20 compressors 22 intercooler 24 Throttle valve 26 turbines 28 exhaust manifold 30 first exhaust aftertreatment device 32 second exhaust aftertreatment device 34 Wave 36 Inlet channel section of the exhaust manifold 38 Exhaust port of the combustion engine 40 Collecting channel section of the exhaust manifold 42 Exhaust manifold outlet duct section 44 Outer casing of the exhaust manifold 46 Inner casing of the exhaust manifold 48 Exhaust manifold connecting element 50 Central channel of the exhaust manifold 52 Exhaust manifold gap channel 54 locking device 56 first aperture ring of the shutter device 58 second aperture ring of the shutter device 60 aperture of an aperture ring 62 Shutter section of the first aperture ring 64 Shutter section of the second aperture ring

Claims

[1] An exhaust manifold (28) for an internal combustion engine (10), which forms at least one inlet channel section (36) for connection to at least one outlet channel (38) associated with a combustion chamber (14) of an internal combustion engine (12) of the internal combustion engine (10), and an outlet channel section (42) for connection to a further section of an exhaust system of the internal combustion engine (10), wherein the exhaust manifold (28) is delimited on the outside by an outer housing (44) and wherein an inner housing (46) is provided which extends at a distance from at least a section of the outer housing (44), whereby a gap channel (52) leading from the inlet channel section (36) in the direction of the outlet channel section (42) is formed, which gap channel can be closed as required by means of a closure device (54), characterized by that the inner housing (46) is longer than the outer housing (44) at a free end of the input channel section (36). [2] Exhaust manifold (28) according to claim 1, characterized by a plurality of inlet channel sections (36) which are provided for connection to outlet channels (38) which are assigned to one or more combustion chambers (14), wherein the inlet channel sections (36) merge into a collecting channel section (40) and the collecting channel section (40) merges into the outlet channel section (42). [3] Exhaust manifold (28) according to claim 1 or 2, characterized by that the closure device (54) is arranged on the outlet side of the gap channel (52). [4] Exhaust manifold (28) according to one of the preceding claims, characterized bythat the closure device (54) is designed as a rotary diaphragm with a first diaphragm ring (56) and a second diaphragm ring (58), which are arranged axially adjacent to and rotatable relative to one another and which each form at least one through-opening (60), wherein the through-openings (60) of the diaphragm rings (56, 58) can be brought into a variable overlap by means of an adjusting device. [5] Exhaust manifold (28) according to one of the preceding claims, characterized by that the inner housing (46) runs parallel to the adjacent sections of the outer housing (44). [6] Exhaust manifold (28) according to one of the preceding claims, characterized by that the inner housing (46) is connected to the outer housing (44) by means of one or more connecting elements (48). [7] Internal combustion engine (10) with an internal combustion engine (12) and an exhaust manifold (28) according to one of the preceding claims. [8] Method for operating an internal combustion engine (10) according to claim 7, characterized by , that - for operation of the internal combustion engine (10) with a value of an operating parameter below a limit value, the closure device (54) is brought into an at least partially closed position and / or - for operation of the internal combustion engine (10) with a value of an operating parameter that is above a limit value, the closure device (54) is brought into the widest possible open position. [9] Internal combustion engine (10) according to claim 7, characterized by a control device which is designed to control the closure device (54) in such a way that a method according to claim 8 can be carried out automatically by means of the closure device.

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