Exhaust Gas Treatment Devices

Abstract

To provide an exhaust gas treatment device 100 for an internal combustion engine 1, the internal combustion engine comprising such an exhaust gas treatment device, and a method for operating such an internal combustion engine.SOLUTION: An exhaust gas treatment device 100 comprises an elongated exhaust manifold 10 with a plurality of inlets 11, and a catalyst container 20 comprising at least one first catalyst element 21, in particular an SCR catalyst element, and a collector section 22. The collector section 22 is connected to an outlet 40 of the exhaust gas treatment device 100 via a pipe 32 crossing the exhaust manifold 10. The exhaust gas treatment device 100 comprises at least one interface 50 for connecting a second catalyst, in particular a fuel slip catalyst 110. The interface 50 comprises at least one interface outlet 51 fluidly connected to the pipe 32, and at least one interface inlet 52 fluidly connected to the outlet 40.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an exhaust gas treatment device for an internal combustion engine, a retrofit kit for such an exhaust gas treatment device, an internal combustion engine equipped with such an exhaust gas treatment device, and a method for operating such an internal combustion engine.

[0002] In particular, the present invention relates to a dual fuel combustion engine capable of using ammonia or methanol or any other toxic or harmful fuel as fuel. Summary of the Invention

[0003] An internal combustion engine may be operated in a gas mode where primarily gaseous fuel is used. An internal combustion engine may also be operated in a liquid mode where primarily liquid fuel, e.g., heavy fuel oil or diesel fuel, is used. As used herein, the terms "gas mode" or "operating in gas mode" refer to the use of gas or gaseous fuel as the fuel for torque-generating combustion. However, in gas mode for ignition of a premixed air-fuel mixture, it is possible and quite common that a small amount of autoignition liquid fuel, e.g., heavy fuel oil or diesel fuel, is injected to effect ignition, but the torque-generating combustion process is still operated primarily with gas or gaseous fuel.

[0004] The internal combustion engine may be a diesel or gas engine, a dual-fuel or multi-fuel engine. The combustion of liquid and / or gaseous fuels in such engines is possible, as is auto-ignition or forced ignition.

[0005] More particularly, the term internal combustion engine includes dual fuel engines and larger engines in which the main fuel is ignited with the aid of a pilot injection of autoigniting fuel, but also those which are alternatively ignited using a pre-chamber solution.

[0006] The term internal combustion engine also includes dual fuel engines, which may be fueled with a conventional fuel, such as diesel or LNG, and with alternative fuels, such as ammonia or methanol, that have reduced greenhouse gas emissions and a lower carbon footprint than conventional fuels. However, operation with alternative fuels may require diesel for forced ignition.

[0007] The present invention preferably relates to internal combustion engines such as large marine or ship engines or stationary engines having a cylinder with an internal diameter of at least 200 mm.

[0008] The internal combustion engine is preferably a two-stroke engine or a two-stroke crosshead engine.

[0009] The internal combustion engine may be a two-stroke engine that may be longitudinally scrubbed.

[0010] The engine speed is preferably less than 800 RPM, more preferably less than 200 RPM, especially for two-stroke engines, indicating a low speed engine designation.

[0011] The fuel can be diesel or marine diesel or heavy fuel oil or emulsion or slurry or methanol or ethanol as well as gases like liquefied natural gas (LNG), liquefied petrol gas (LPG), etc. Further possible fuels that can be added on demand are: LBG (Liquefied Biogas), biological fuels (e.g. oil obtained from algae), hydrogen, synthetic fuels from CO2 (e.g. made by power-to-gas or power-to-liquid).

[0012] Ammonia-fuelled ships, or engines adapted to be powered by ammonia fuel, are increasingly being developed and built in accordance with the 2018 International Maritime Organisation commitment to reduce greenhouse gas emissions from international shipping.

[0013] Ammonia is a synthetic product obtained from fossil fuels, biomass, or renewable sources (wind, solar, hydro, or heat); when produced by renewable sources, ammonia has virtually no carbon footprint or produces any CO when burned. 2 , S.O. X , particulate matter, or unburned hydrocarbons. The same is true for other harmful fuels.

[0014] Ammonia is hazardous and has a pungent odor, so when the fuel is ammonia, it is desirable to minimize the release of ammonia gas, especially for the safety of the crew and when the engine is shut down due to a change to a conventional fuel or due to an unforeseen event.

[0015] Typically, the exhaust gases are treated in an exhaust gas aftertreatment device to remove any harmful components of the exhaust gases.

[0016] EP 2 527 611 A1 proposes a compact design of an aftertreatment device, in which an elongated exhaust gas manifold and a catalyst container are arranged parallel to one another and separated from one another by a longitudinally extending partition wall.

[0017] The exhaust gas receiver may be fluidly connected to the turbocharger and may also be fluidly connected to some type of aftertreatment.

[0018] For example, an aftertreatment system for a dual fuel diesel ammonia engine, as disclosed in WO 2023 / 049925, may include an ammonia slip catalyst (ASC) positioned directly downstream of a selective catalytic reduction (SCR) catalyst.

[0019] All of the piping and valves for such fluid connections take up space and need to be customized for each engine system depending on which turbocharger, which turbocharger arrangement, and which exhaust gas treatment device arrangement and components are used. This adds complexity and cost.

[0020] For the addition of a fuel slip catalyst to the exhaust gas treatment device, which may be beneficial for reducing residual ammonia or methanol, additional piping and valves must be installed, all with the risk of leaks, further increasing complexity and cost.

[0021] The object of the present invention is therefore to at least partially overcome the drawbacks of the prior art and in particular to create an exhaust gas treatment device, a retrofit kit for such an exhaust gas treatment device, an internal combustion engine equipped with such an exhaust gas treatment device, and a method for operating such an internal combustion engine that provides safer operation and / or is less complex.

[0022] That object is achieved by the device and method of the independent claims.

[0023] Accordingly, as a first aspect of the present invention, an exhaust gas treatment device for an internal combustion engine comprises an elongated exhaust gas manifold having a plurality of inlets and a catalyst vessel.

[0024] Typically, each inlet connects a respective cylinder outlet with an elongated exhaust manifold. The inlets may be positioned next to each other along a longitudinal axis of the elongated exhaust manifold.

[0025] The catalyst vessel comprises at least a first catalyst element and a collector section disposed downstream of the catalyst element such that exhaust gas that has passed through the catalyst element can enter the collector section.

[0026] The internal combustion engine may be a dual fuel internal combustion engine, which may be fuelled, for example, with diesel and ammonia or diesel and methanol.

[0027] The first catalytic element may be a selective catalytic reduction (SCR) catalytic element. Selective catalytic reduction refers to the catalytic conversion of nitrogen oxides, also called NOx, into nitrogen and water. Typically, a reducing agent, such as anhydrous ammonia, aqueous ammonia, or a nitrogen solution, is added to the exhaust gas stream and reacted on the catalyst.

[0028] The collector section is fluidly connected or connectable to an outlet of the exhaust gas treatment device via a piping that crosses the exhaust gas manifold, so that the outlet of the exhaust gas treatment device can be located close to the exhaust gas manifold, providing a compact design.

[0029] The exhaust gas treatment device comprises at least one interface for connecting a second catalyst, in particular a fuel slip catalyst, such as an ammonia slip catalyst (ASC) or a diesel oxidation catalyst (DOC), which may provide for reducing the emission of slip fuel and / or reductant, in particular for removing residual ammonia.

[0030] The second catalyst may comprise at least one second catalyst element and a second catalyst container for housing the second catalyst element.

[0031] The interface comprises at least one interface outlet fluidly connected to the pipe and at least one interface inlet fluidly connected to the outlet.

[0032] The interface is disposed downstream of the first catalytic element, where the term "downstream" refers to the typical flow direction of exhaust gases from the cylinder to the outlet.

[0033] The interface provides for mounting a second catalyst downstream of the first catalyst and upstream of the outlet.

[0034] The interface outlet may be fluidly connected or connectable to the inlet of the second catalyst.The interface inlet may be fluidly connected or connectable to the outlet of the second catalyst.

[0035] The interface allows, inter alia, to upgrade existing exhaust gas treatment devices by adding or substituting a second catalyst.

[0036] When the interface outlet is connected to a pipe that is fluidly connected to the outlet, the arrangement provides not only treatment in the second catalyst, but also, or alternatively, a bypass to bypass the interface and the second catalyst, if necessary or advantageous.

[0037] In a preferred embodiment, the exhaust gas manifold and the catalyst vessel may be disposed adjacent to each other and separated from each other by at least one partition, and the exhaust gas manifold may be fluidly connected or connectable to the catalyst vessel via at least one hole provided in the at least one partition for directing exhaust gas through the first catalyst element to the collector section during operation.

[0038] In said arrangement, no piping elements between the exhaust gas manifold and the catalyst vessel are required to guide the exhaust gas from the exhaust gas manifold to the catalyst vessel. Furthermore, thermal contact between the exhaust gas manifold and the catalyst vessel is easier to establish. Thermal contact may have advantages with regard to providing a sufficiently high operating temperature of the catalyst without the need for additional heating.

[0039] The exhaust gas manifold and the catalyst vessel may be arranged in a common housing and / or on a common frame, which may also be advantageous in terms of size and / or thermal contact.

[0040] The catalyst vessel may include two first catalyst elements, for example arranged at opposite side ends of the catalyst vessel. Thus, the partition may comprise a plurality of holes, for example at a side end of an elongated exhaust gas manifold. After passing through the first catalyst elements, the exhaust gas may be collected in a central collector section arranged between the two catalysts.

[0041] The catalyst vessel may comprise at least two catalyst elements arranged parallel to one another, which are supplied with exhaust gas by the same hole in the partition.

[0042] The pipe may form a further opening in the partition or may be fixed to an opening in the partition so that the exhaust gases may leave the collector section and traverse the elongated manifold on their way to the outlet.

[0043] A pipe branch point can advantageously be arranged in the exhaust gas manifold, on the one hand to connect the pipe to the outlet and on the other hand to connect the pipe to at least one interface outlet, which can lead to a reduction in size and / or a better thermal contact.

[0044] A pipe branch typically connects one inlet section and two outlet branches. A pipe may be formed by the inlet section and one of the branches, while the other branch connects to an interface outlet.

[0045] The pipe branch provides a fluid connection of the collector section and an outlet via the pipe on the one hand and the collector section and at least one interface outlet via the pipe and a tributary branching off from the pipe on the other hand.

[0046] Alternatively, the pipe branch may be located within an exhaust manifold, connected to a pipe.

[0047] A pipe branch typically connects an inlet section and at least two or more outlet branches. A pipe may be formed by the inlet section and one of the branches while the other branch connects to an interface outlet. Each of the other branches provides a pipe fluidly connecting to each of the at least two interface outlets while the pipe provides for directing exhaust gases directly to the outlet.

[0048] At least one interface outlet may preferably be accessible from outside the exhaust manifold. In particular, the interface outlet is arranged on the exhaust manifold or outside the exhaust manifold. This leads to better accessibility, e.g. for service operations and / or for connection to piping or to a second catalyst.

[0049] A tributary at or from a pipe branch may traverse the housing of the elongated exhaust manifold to the exterior of the elongated exhaust manifold.

[0050] Pipe elements or partitions that cross sections of the housing provide additional stability since they must be fixed to avoid leakage. Thermal variations have the same effect on all sections so that thermal compensation elements are not necessary.

[0051] The interface may comprise connection means, for example flanges, for fixing the pipe and / or for fixing the second catalyst.

[0052] A second catalyst can be attached to the interface, or an already installed second catalyst can be replaced without affecting the exhaust gas treatment device, in particular without opening the exhaust gas manifold. The exhaust gas treatment device is therefore more generally applicable, since it can be used with or without an installed second catalyst. The interface also allows for easy installation of a suitable second catalyst, for example when an internal combustion engine is to be fueled with a new fuel.

[0053] The interface outlet may advantageously comprise an interface outlet valve. In particular, the interface outlet valve is arranged at the interface outlet. The interface outlet valve may provide for opening or closing a fluid connection between the pipe and the interface outlet, in particular between the pipe and the second catalyst. The interface outlet valve may preferably provide for controlling the flow rate through the interface outlet.

[0054] One example of such an interface outlet valve, as well as all other valves in this application, is the butterfly valve. Such valves are readily available in the required diameters and exhibit a narrow profile which is advantageous for installation. Furthermore, flow regulation is possible.

[0055] Preferably, the interface outlet valve is accessible from the outside of the exhaust gas manifold, which leads to better accessibility, for example for service operations and / or for connecting to piping or to a second catalyst.

[0056] The interface outlet valve may be set to a closed state when there is no second catalyst installed in the interface, or in some cases when directing exhaust gases to the second catalyst is not essential or desirable. Fuel slip may not be expected, for example, when the internal combustion engine is operated in diesel mode and there is no excess reductant. Thus, a second catalyst may be avoided, which is advantageous in terms of life and performance.

[0057] The interface inlet may preferably include an interface inlet valve. In particular, the interface inlet valve is disposed at the interface inlet. The interface inlet valve may provide for opening and closing the fluid connection between the second catalyst and the outlet. The interface inlet valve may also provide for controlling the flow rate through the interface inlet.

[0058] When there is no second catalyst attached to the interface, or in some cases when directing exhaust gases to the second catalyst is not required or desirable, the interface inlet valve may be set to a closed state. A closed interface inlet valve may prevent backflow of exhaust gases to the second catalyst. Thus, the second catalyst may be avoided, which is advantageous in terms of life and performance.

[0059] The exhaust gas manifold may advantageously be directly fluidly connectable to the outlet via a bypass pipe, in particular the bypass pipe preferably comprising a bypass valve arranged within the bypass pipe.

[0060] When it is not necessary or desirable to direct the exhaust gases through the first catalytic element or through the first catalytic element and the second catalytic element, for example when exhaust gas treatment is to be avoided, for example for cost reasons, the bypass valve can be set to an open state.

[0061] The exhaust gas treatment device may further comprise a main outlet valve, preferably arranged in or downstream of the pipe. The main outlet valve is in particular accessible from outside the exhaust gas manifold. The main outlet valve may provide for opening and closing the fluid connection between the collector section and the outlet. The main outlet valve may also preferably provide for controlling the flow rate between the collector section and the outlet.

[0062] The main outlet valve may be located downstream of and / or within a pipe branch or pipe branch such that when the main outlet valve is set to a closed state, exhaust gas leaving the collector section is forced into one or more other tributaries and toward one or more interface outlets.

[0063] The exhaust gas treatment device may alternatively or additionally comprise at least one main inlet valve arranged between the exhaust gas manifold and the catalyst container, in particular in at least one hole arranged in a partition between the exhaust gas manifold and the catalyst container.

[0064] The main inlet valve may provide for opening and closing a fluid connection between the exhaust manifold and the catalyst vessel. The main inlet valve may also provide for controlling the flow rate between the exhaust manifold and the catalyst vessel.

[0065] The main inlet valve may be set to a closed state so that exhaust gases cannot be directed to the respective first catalytic element.

[0066] The exhaust gas treatment device may include a plurality of main inlet valves, some of which may be set in a closed state to use only a portion of the first catalytic element.

[0067] By setting all first main inlet valves to the closed state and by setting the exhaust bypass valves to the open state, the exhaust gases can be directed completely directly to the outlet.

[0068] The exhaust gas treatment device may advantageously comprise at least one second catalyst, in particular at least one fuel slip catalyst, connected to the at least one interface.

[0069] A fuel slip catalyst, such as an ammonia slip catalyst, may also be provided to remove residual reductant, which may be injected, for example, into an exhaust gas treatment device upstream of the first catalytic element.

[0070] The second catalyst may preferably be disposed at a side end of the catalyst vessel and / or in thermal contact with the catalyst vessel, which is advantageous in terms of providing a sufficiently high operating temperature of the second catalyst without the need for additional heating.

[0071] The second catalyst may be disposed on the exhaust manifold and / or in thermal contact with the exhaust manifold. The second catalyst may be disposed on an outer wall of the exhaust manifold, which may be disposed opposite a partition between the exhaust manifold and the catalyst vessel.

[0072] In particular, the second catalyst may be integrated into the exhaust manifold. The second catalyst may be arranged in a common housing with the exhaust manifold, preferably in a common housing with the catalyst housing.

[0073] The second catalyst may be mounted in a frame, which may be secured to the exhaust gas manifold and / or to the catalyst container.

[0074] The placement of the second catalyst close to the exhaust manifold provides a compact design and better heat transfer. The second catalyst can be warmed by the hot exhaust gases leaving the cylinder and entering the exhaust manifold. This is advantageous with regard to providing a sufficiently high operating temperature of the second catalyst without the need for additional heating.

[0075] The exhaust gas treatment device may advantageously comprise at least two second catalysts connected to at least one interface, the volume flow of exhaust gas leaving the collector section then being split into at least two gas flows of respective second catalysts.

[0076] Thus, multiple second catalysts can be used in parallel, leading to higher contact area and lower velocity with split volumetric exhaust gas flow. Thus, the pressure drop across each second catalyst is lower compared to a serial arrangement of second catalysts. This is advantageous in terms of performance and catalytic efficiency.

[0077] According to a second aspect of the invention, an internal combustion engine, in particular a dual-fuel combustion engine, preferably an ammonia-fueled combustion engine, comprises at least one cylinder and at least one exhaust gas treatment device as described above with respect to the first aspect of the invention.

[0078] An internal combustion engine may be equipped with one, in particular exactly one, exhaust gas treatment device for all cylinders of the engine.

[0079] An internal combustion engine may be equipped with one, in particular exactly one, exhaust gas treatment device as described above for up to seven cylinders of the engine, in particular for up to six cylinders of the engine, in particular for up to four cylinders of the engine. This is due to the fact that, via a specified number of cylinders, a second, third etc. manifold is usually used, which has its own second, third etc. exhaust gas treatment device.

[0080] The internal combustion engine may preferably be equipped with a turbocharger, which may be in fluid communication or is connected to an outlet of the exhaust gas treatment device.

[0081] The internal combustion engine may advantageously comprise a control unit adapted to switch between a first operating mode, a second operating mode and a third operating mode.

[0082] In a first operating mode (e.g., Tier 2), the bypass valve is open. In the first operating mode, the main inlet valve and the main outlet valve are closed, while preferably the interface outlet valve is closed, while preferably the interface inlet valve is also closed.

[0083] In the first operating mode, the exhaust gases may be directed directly to the outlet without passing through the catalyst housing and the second catalyst, which saves costs.

[0084] In a second operating mode (e.g. IMO Tier III diesel operation or IMO Tier III ammonia operation without a second catalyst), the bypass valve is closed. In the second operating mode, the main inlet valve and the main outlet valve are open, while the interface outlet valve is closed and preferably the interface inlet valve is also closed. In the second operating mode, exhaust gases are directed only through the catalyst housing without passing through the second catalyst. Thus, for example, NOx reduction can be achieved without a second catalyst, e.g. ASC, e.g. in diesel operating mode. This leads to improved performance and durability of the second catalyst.

[0085] In a third mode of operation (e.g., IMO Tier III ammonia operation with a second catalyst), the bypass valve is closed. In the third mode of operation, the main inlet valve is open and the main outlet valve is closed, while the interface outlet valve and the interface inlet valve are open.

[0086] In a third operating mode, the exhaust gases can be directed through the catalyst housing and then through a second catalyst, thus enabling, for example, both NOx reduction and the use of a second catalyst, e.g., ASC, which leads to cleaner exhaust gases.

[0087] Similar operating modes can be defined for methanol operation of an internal combustion engine.

[0088] A main inlet valve is preferably disposed in at least one of the holes.

[0089] The main outlet valve is preferably located in or downstream of the pipe.

[0090] An interface outlet valve is preferably disposed at the interface outlet.

[0091] The interface inlet valve is preferably located at the interface inlet.

[0092] According to a third aspect of the invention, a retrofit kit for an exhaust gas treatment device as described above with respect to the first aspect of the invention comprises at least one second catalyst, in particular at least one fuel slip catalyst, connectable to the interface.

[0093] In this context, "connectable" means, in particular, that the interface and the second catalyst are fluidly connected or fluidly connectable after a connection between the interface and the second catalyst is established.

[0094] In this context, "fluidly connectable" means that when an obstruction is removed from a fluid line, for example when a valve is opened, a fluid connection can be achieved.

[0095] In particular, the at least one second catalyst comprises a piping system having a first piping connectable to the interface outlet and a second piping connectable to the interface inlet. Preferably, a flange connection may be established.

[0096] The retrofit kit may be used, for example, to equip an already existing exhaust gas treatment device with, for example, a fuel slip catalyst, or to replace a fuel slip catalyst in the exhaust gas treatment device.

[0097] A fourth aspect of the invention relates to a method for operating an internal combustion engine as described above with respect to the second aspect of the invention, comprising an exhaust gas treatment device according to the first aspect of the invention.

[0098] To operate the internal combustion engine in a first operating mode, the bypass valve is opened. For the first operating mode, the main inlet valve and the main outlet valve are closed, and the interface outlet valve and preferably the interface inlet valve are closed.

[0099] As long as the internal combustion engine is in the first operating mode, the valve settings are not changed and the exhaust gases are directed directly to the outlet and are not allowed to pass through the first catalyst element and the second catalyst.

[0100] To operate the internal combustion engine in a second operating mode, the bypass valve is closed. For the second operating mode, the main inlet valve and the main outlet valve are opened and the interface outlet valve and preferably the interface inlet valve are closed.

[0101] As long as the internal combustion engine is in the second operating mode, the valve settings are not changed and exhaust gases are directed through the catalytic element but are not permitted to pass through the second catalyst.

[0102] To operate the internal combustion engine in a third operating mode, the bypass valve is closed. For the third operating mode, the main inlet valve is opened and the main outlet valve is closed, while the interface outlet valve and the interface inlet valve are opened.

[0103] As long as the internal combustion engine is in the third operating mode, the valve settings are not changed and the exhaust gases are directed through the catalytic element and thereafter through the second catalyst.

[0104] The operating mode may be set by the control unit depending on parameters of the internal combustion engine, such as load, ambient temperature, engine temperature, engine pressure, fuel mode, etc., or depending on regulatory mandates.

[0105] Further advantageous aspects of the invention are explained below with the aid of exemplary embodiments and figures, in which functionally equivalent elements are given the same reference numbers. [Brief description of the drawings]

[0106] [Figure 1] 1 shows a schematic diagram of an internal combustion engine. [Diagram 2] 1 shows a schematic diagram of a first example of an exhaust gas treatment device in a perspective view. [Diagram 3] 2 shows a schematic diagram of a second example of an exhaust gas treatment device in cross-sectional view. [Figure 4] 3 shows a schematic diagram of a first example of the exhaust gas treatment device of FIG. 2 in a perspective view with a cross section. [Diagram 5] 1 shows a schematic diagram of a third example of an exhaust gas treatment device in a perspective view. [Figure 6] 1 shows a schematic diagram of a portion of a fourth example of an exhaust gas treatment device in a perspective view. [Figure 7] 1 shows a schematic diagram of a fifth example of an exhaust gas treatment device in a perspective view.

[0107] FIG. 1 shows a schematic diagram of an internal combustion engine 1 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0108] The internal combustion engine 1 comprises a cylinder 2 and an exhaust gas treatment device 100 having an elongated exhaust gas manifold 10, a catalyst container 20 and a second catalyst 110. The internal combustion engine 1 further comprises a turbocharger 3 and a funnel 4.

[0109] Exhaust gas leaving the cylinder 2 may be directed through an exhaust gas treatment device 100 and then through the turbocharger 3 before it is discharged through a funnel 4 .

[0110] All components have large space requirements and since the available space on board is limited, it is important to arrange the components in a compact manner whilst at the same time allowing access.

[0111] The internal combustion engine 1 is typically equipped with a control unit 70 for controlling the piston movement and the cylinder valves (not shown in this figure) as well as the valves of the exhaust gas treatment device 100 .

[0112] FIG. 2 shows an exhaust gas treatment device 100 comprising an elongated exhaust gas manifold 10 and a catalyst vessel 20 .

[0113] The exhaust gas treatment device 100 comprises an outlet 40 which may be connected to a turbocharger 3 (see FIG. 1).

[0114] A bypass pipe 41 with a bypass valve 42 fluidly connects the elongated exhaust manifold 10 to the outlet when the bypass valve 42 is open.

[0115] The exhaust gas treatment device 100 comprises an interface 50 for connecting a second catalyst 110 (not shown in this figure) The interface 50 comprises an interface outlet 51 fluidly connected to a pipe 32 (not shown in this figure) and at least one interface inlet 52 fluidly connected to an outlet 40 (see also FIG. 4).

[0116] The valves of the exhaust gas treatment device 100, such as the bypass valve 42, are controlled by a control unit 70. The valves may be set to an open or closed position or any position in between to control the flow rate of the fluid connections through the valves. In this example, the control unit for controlling the exhaust gas treatment device 100 is the same as the control unit of the combustion engine 1 (see FIG. 1 ). Alternatively, there may be a separate control unit for controlling the exhaust gas treatment device 100, or the control unit for controlling the exhaust gas treatment device 100 may be part of or integrated into the control unit of the combustion engine 1.

[0117] FIG. 3 shows a schematic diagram of a second example of an exhaust gas treatment device 100 according to the present invention in a cross-sectional view.

[0118] The catalyst vessel 20 accommodates two first catalyst elements 21 , in particular SCR catalyst elements, and a collector section 22 arranged between the first catalyst elements 21 .

[0119] The elongated exhaust gas manifold 10 and the catalyst vessel 20 are arranged next to each other and separated from each other by a partition 30. Thus, space is saved and thermal contact between the exhaust gas manifold and the catalyst vessel is easier to establish. The exhaust gas manifold 10 is fluidly connected or connectable to the catalyst vessel 20 via holes 31 provided in the partition 30 for directing the exhaust gas through the first catalyst element 21 to the collector section 22 during operation.

[0120] A main inlet valve 34 is disposed in each hole 31. Exhaust gas may enter the first catalyst vessel 20 when the main inlet valves 34 are open. The exhaust gas is directed through the first catalyst element 21 and then collected in the collector section 22.

[0121] The collector section 22 is connected to an outlet 40 (not shown in this figure) of the exhaust gas treatment device 100 via a pipe 32 that traverses the exhaust gas manifold 10 .

[0122] A pipe branch 33 is arranged in the exhaust gas manifold 10 adapted to connect the pipe 32 to the outlet 40 on the one hand and to connect the pipe 32 to the interface outlet 51 on the other hand.

[0123] The exhaust gas may be branched off from pipe 32 and directed to interface outlet 51 .

[0124] The elongated exhaust gas manifold 10 is provided with a bypass opening 43 by which the exhaust gases can be directed to the outlet 40 (not shown in this figure).

[0125] FIG. 4 shows a schematic diagram of the first example of FIG. 2 in a further perspective view with a cross section.

[0126] An elongated exhaust manifold 10 is provided with a number of inlets 11 for bringing exhaust gases discharged from the cylinders 2 (see FIG. 1) into the elongated exhaust manifold 10 .

[0127] A pipe branch 33 is arranged in the exhaust gas manifold 10 adapted to connect the pipe 32 to the outlet 40 on the one hand and to connect the pipe 32 to the interface outlet 51 on the other hand.

[0128] A main outlet valve 23 is located in one of the branches of the pipe branch 33 and an interface outlet valve 53 is located in the other branch.

[0129] Depending on the valve settings, exhaust gas coming from the collector section 22 is directed to the outlet 40 or to the interface outlet 51 (or both in a specific ratio based on the flow rate settings of the valves). The second catalyst may have an optimum capacity that may be related to a specific flow rate. By setting the valves appropriately, maximum reduction of harmful components may be achieved.

[0130] When the main outlet valve 23 is open and the interface outlet valve 53 is closed, the exhaust gas is directed to the outlet 40 .

[0131] When the main outlet valve 23 is closed and the interface outlet valve 53 is open, the exhaust gas is directed to the interface outlet 51 .

[0132] Downstream of the main outlet valve 23 and upstream of the outlet is an interface inlet 52. Plumbing (not shown in this view) to a second catalyst 110 (not shown in this view) may bring exhaust gases from the second catalyst into the interface inlet 52.

[0133] Alternatively, a bypass valve 42 disposed in the bypass pipe 41 may, when open, direct exhaust gases from the elongated exhaust manifold 10 directly to the outlet 40 .

[0134] FIG. 5 shows a schematic diagram of a third example of an exhaust gas treatment device 100 in a perspective view.

[0135] The exhaust gas treatment device 100 comprises an elongated exhaust gas manifold 10 and a catalyst vessel 20 .

[0136] The exhaust gas treatment device 100 includes an interface 50 having an interface outlet 51 and an interface inlet 52 .

[0137] A second catalyst 110 mounted at the longitudinal end L of the catalyst vessel 20 may be fluidly connected to the interface 50 via a piping system 111 .

[0138] When an interface outlet valve 53 located downstream of the interface outlet 51 and an interface inlet valve 54 located upstream of the interface inlet 52 are opened, a fluid coupling between the interface 50 and the second catalyst 110 can be established.

[0139] 6 shows in perspective view a schematic diagram of a portion of a fourth example of an exhaust gas treatment device 100. A second catalyst 110 is mounted on a frame 60 fixed to a longitudinal end L of the elongated exhaust gas manifold 10.

[0140] Since the interface outlet 51 is located at the side end L of the elongated exhaust manifold 10, a short piping system 111 is sufficient to fluidly connect the second catalyst 110. This saves space and creates better thermal contact.

[0141] FIG. 7 shows a schematic diagram of a fifth example of an exhaust gas treatment device 100 in a perspective view.

[0142] The exhaust gas treatment device 100 comprises two interface outlets 51 and two interface inlets 52 each having a respective interface outlet valve 53 or interface inlet valve 54 .

[0143] Thus, two second catalysts 110 are mounted on the elongated exhaust manifold 10 at each of its longitudinal ends L.

[0144] One branch 35 of a pipe branch 33 (not shown in this figure) arranged in the elongated exhaust manifold 10 provides two interface outlets 51 towards the side end L of the elongated exhaust manifold 10. Thus, the pressure drop across each second catalyst is lower compared to a series arrangement of second catalysts. This is advantageous in terms of performance and catalytic efficiency.

[0145] Note: Any embodiment described with respect to a device shall likewise relate to the method. Synergistic effects may result from different combinations of embodiments that may not be described in detail.

[0146] While presently preferred embodiments of the invention have been shown and described, it is to be clearly understood that the invention is not limited thereto and may be variously otherwise embodied and practiced within the scope of the following claims. [Explanation of symbols]

[0147] 1. Internal combustion engine 2 Cylinder 3. Turbocharger 4 funnel 10. Long and narrow exhaust manifold 11 Multiple Entrances 20 Catalyst container 21 First catalytic element 22 Collector Section 23 Main Outlet Valve 30 Partition 31 holes 32 Pipe 33 Pipe Junction 34 Main inlet valve 35 Tributaries 40 exit 41 Bypass Pipe 42 Bypass valve 43 Bypass opening 50 Interface 51 Interface Exit 52 Interface Entrance 53 Interface Outlet Valve 54 Interface Inlet Valve 60 frames 70 Control Unit 100 Exhaust gas treatment device 110 The Second Catalyst 111 Piping System

Claims

1. An exhaust gas treatment device (100) for an internal combustion engine (1), said internal combustion engine (1) being a dual-fuel internal combustion engine fuelled by ammonia, an elongated exhaust gas manifold (10) having a plurality of inlets (11); A catalyst vessel (20) comprising at least one first catalyst element (21) and a collector section (22). Equipped with the collector section (22) is connected to an outlet (40) of the exhaust gas treatment device (100) via a pipe (32) that crosses the exhaust gas manifold (10); the exhaust gas treatment device (100) comprises at least one interface (50) for connecting a second catalyst; The exhaust gas treatment device (100), characterized in that the interface (50) comprises at least one interface outlet (51) fluidly connected to the pipe (32) and at least one interface inlet (52) fluidly connected to the outlet (40).

2. The exhaust gas treatment device (100) of claim 1, wherein the at least one first catalytic element (21) is an SCR catalytic element.

3. The exhaust gas treatment device (100) of claim 1, wherein the second catalyst is a fuel slip catalyst.

4. 2. The exhaust gas treatment device (100) of claim 1, wherein the exhaust gas manifold (10) and the catalyst container (20) are arranged adjacent to each other and separated from each other by at least one partition (30), and the exhaust gas manifold (10) is fluidly connected or connectable to the catalyst container (20) via at least one hole (31) provided in the at least one partition (30) to direct exhaust gas through the first catalyst element (21) to the collector section (22) during operation.

5. 2. The exhaust gas treatment device (100) of claim 1, wherein a pipe branch is arranged in the exhaust gas manifold (10) adapted to connect the pipe (32) to the outlet (40) on the one hand and to at least one interface outlet (51) on the other hand.

6. The exhaust gas treatment device (100) of claim 1, wherein the interface outlet (51) is accessible from outside the exhaust gas manifold (10).

7. The exhaust gas treatment device (100) of claim 1, wherein the interface outlet (51) comprises an interface outlet valve (53).

8. The exhaust gas treatment device (100) of claim 1, wherein the interface inlet (52) comprises an interface inlet valve (54).

9. The exhaust gas treatment device (100) of claim 1, wherein the exhaust gas manifold (10) is directly fluidly connectable to the outlet (40) via a bypass pipe (41).

10. Main outlet valve (23) and At least one of the main inlet valves (34) disposed between the exhaust gas manifold (10) and the catalyst vessel (20); The exhaust gas treatment device (100) of claim 1 further comprising:

11. The exhaust gas treatment device (100) of claim 1, comprising at least one second catalyst connected to the at least one interface (50).

12. The second catalyst (110) is Located at the side end (L) of the catalyst container (20), placed in thermal contact with the catalyst vessel (20); located on the exhaust gas manifold (10); or disposed in thermal contact with said exhaust gas manifold (10); The exhaust gas treatment device (100) of claim 11.

13. The exhaust gas treatment device (100) of claim 11, wherein the second catalyst (110) is mounted on a frame (60) secured to at least one of the exhaust gas manifold (10) and the catalyst container (20).

14. The exhaust gas treatment device (100) of claim 11, comprising at least two second catalysts (110) connected to the at least one interface (50).

15. 10. An internal combustion engine (1), such as a dual fuel combustion engine and an ammonia fuelled combustion engine, comprising at least one cylinder (2) and at least one exhaust gas treatment device (100) according to claim 1.

16. 16. An internal combustion engine according to claim 15, comprising a turbocharger (3) fluidly connectable or connected to the outlet (40) of the exhaust gas treatment device (100).

17. a first mode of operation in which the bypass valve (42) is open and the main inlet valve (34) and the main outlet valve (23) are closed; a second mode of operation in which the bypass valve (42) is closed, the main inlet valve (34) and the main outlet valve (23) are open, and an interface outlet valve (53) is closed; a third mode of operation in which the bypass valve (42) is closed, the main inlet valve (34) is open, the main outlet valve (23) is closed, and the interface outlet valve (53) and interface inlet valve (54) are open; 16. An internal combustion engine according to claim 15, comprising a control unit (70) adapted to switch between the operating modes.

18. 2. A retrofit kit for an exhaust gas treatment device (100) as described in claim 1 comprising at least one second catalyst (110) connectable to the interface (50), the at least one second catalyst (110) comprising a first pipe connectable to an interface outlet (51) and a second pipe connectable to an interface inlet (52), the second catalyst being a fuel slip catalyst.

19. For a first mode of operation, the main inlet valve (34) and the main outlet valve (23) are closed, the interface outlet valve (53) and the interface inlet valve (54) are closed, and the bypass valve (42) is opened. For a second mode of operation, the main inlet valve (34) and the main outlet valve (23) are opened, the interface outlet valve (53) and the interface inlet valve (54) are closed, and the bypass valve (42) is closed. For a third mode of operation, the main inlet valve (34) is opened, the main outlet valve (23) is closed, the interface outlet valve (53) and the interface inlet valve (54) are opened, and the bypass (42) valve is closed.

20. A method for operating an internal combustion engine as claimed in claim 17.

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