Internal combustion engine and exhaust system

Abstract

To provide an internal combustion engine and exhaust treatment unit that offer stable combustion and save space. [Solution] According to the present invention, the internal combustion engine 100 has an intake system 3 for introducing scavenging gas into the cylinder 1 and an exhaust system 101 for discharging exhaust gas generated in the cylinder 1. The exhaust system includes an exhaust gas receiver 4 connected to the cylinder 1 via an exhaust outlet 25 for discharging exhaust gas, and an exhaust treatment unit 5. The exhaust treatment unit 5 has at least one exhaust gas cooler 6 and a duct system 7 for guiding a cooling medium such as water. The exhaust system has at least one heat exchanger 11a, 11b, the heat exchanger having first fluid lines 12a, 12b that are fluid-connected to or fluid-connectable to the duct system 7, and is configured to receive a cooling medium from at least one exhaust gas cooler 6.

Description

Technical Field

[0001] The present invention relates to an internal combustion engine and an exhaust system.

Background Art

[0002] The present invention preferably relates to an internal combustion engine such as a large marine engine or a stationary engine, the cylinder of which has an inner diameter of at least 200 mm. The engine is preferably a two-stroke engine or a two-stroke crosshead engine. The engine may be a gas engine, a dual-fuel engine, or a multi-fuel engine. In such an engine, combustion of liquid fuel and / or gaseous fuel is possible, and self-ignition or forced ignition is also possible.

[0003] The internal combustion engine may be a vertical flash two-stroke engine.

[0004] The term internal combustion engine also refers to large engines that can be operated not only in diesel mode characterized by self-ignition of fuel, but also in Otto mode characterized by positive ignition of fuel, or a mixed mode of the two. Furthermore, the term internal combustion engine includes particularly dual-fuel engines and large engines that utilize self-ignition of fuel for positive ignition of other fuels.

[0005] The engine speed is preferably less than 800 RPM, particularly for a four-stroke engine, and more preferably less than 200 RPM, which indicates a low-speed engine, particularly for a two-stroke engine.

[0006] The fuel may be not only diesel oil, marine diesel oil, heavy oil, emulsion, slurry, methanol, ethanol, but also gases such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG).

[0007] Additional fuels that can be added upon request include liquefied biogas (LBG), biofuels (e.g., oil made from algae or seaweed), ammonia, hydrogen, and synthetic fuels made from carbon dioxide (e.g., produced by power-to-gas or power-to-liquid).

[0008] Large vessels, especially those transporting goods, are typically powered by internal combustion engines, particularly diesel and / or gas engines, mostly two-stroke crosshead engines. Both liquid fuels, such as heavy fuel oil, marine diesel fuel, diesel, or other liquids, and gaseous fuels, such as LNG, LPG, or other gaseous fuels, are burned by the engines, and the exhaust resulting from this combustion process must be purified to comply with current regulations, such as the International Maritime Organization Tier III regulations.

[0009] To reduce the reactivity of the gas / air mixture and methane slip, it is known to provide low-pressure exhaust gas recirculation (EGR), as shown, for example, in European Patent Application Publication No. 3722572(A1). To stabilize combustion, it is advantageous to cool the recirculated exhaust gas.

[0010] Turbocharger compressors can be subjected to shock and corrosion due to moisture in exhaust gases. Chinese Patent Application Publication No. 112628033(A) proposes an EGR system with condensate separation components and a mixer. Since exhaust gas and fresh gas are mixed and moisture is removed, the possibilities for system placement are limited.

[0011] U.S. Patent No. 10,054,085(B2) describes a power system having an EGR cooler which is a single-stage or two-stage heat exchanger. The heat used to vaporize the fuel for the power system may be provided by the heat exchanger. The exhaust gas must be guided through the heat exchanger.

[0012] Typically, low-pressure EGR solutions require additional space within the engine room. Furthermore, low-pressure EGR solutions lower the exhaust enthalpy after the engine, resulting in less steam. This reduction in steam volume can cause problems with standard exhaust gas economizers. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] European Patent Application Publication No. 3722572(A1) [Patent Document 2] Chinese Patent Application Publication No. 112628033(A) [Patent Document 3] U.S. Patent No. 10,054,085(B2) [Overview of the project] [Problems that the invention aims to solve]

[0014] The objective of this invention is to eliminate the shortcomings of the prior art, and in particular to provide an internal combustion engine and exhaust treatment unit that achieve space savings while providing stable combustion without impairing enthalpy, and preferably prevents the harmful effects of condensed water. [Means for solving the problem]

[0015] This objective is achieved by the internal combustion engine described in the independent claim.

[0016] An internal combustion engine has at least one cylinder. In particular, the internal combustion engine is a large marine engine having at least one cylinder with a bore of at least 200 mm, and is preferably a low-pressure fuel gas engine or a dual-fuel engine.

[0017] At least one cylinder has at least one gas admission valve for injecting low-pressure fuel gas directly into the cylinder through the cylinder wall.

[0018] At least one cylinder has at least one exhaust outlet. The exhaust valve may be disposed within the exhaust outlet.

[0019] The internal combustion engine further has an intake system through which scavenging gas is introduced into the cylinder.

[0020] The intake system may have a pipe fluidly connected to the intake port of the cylinder.

[0021] The intake system may have a scavenging receiver. The gas may be guided through a scavenging cooler before entering the scavenging receiver. The scavenging can enter the cylinder through a scavenging port in the cylinder wall.

[0022] The internal combustion engine further has an exhaust system through which the exhaust gas generated within the cylinder is discharged. The exhaust system includes an exhaust gas receiver connected to the cylinder via an exhaust outlet for discharging the exhaust gas from the cylinder.

[0023] The exhaust outlet of the cylinder may be connected, for example, to an exhaust duct leading to an exhaust gas receiver that collects the exhaust gas of a plurality of cylinders.

[0024] The exhaust gas receiver preferably has an elongated hollow cylindrical body made of, for example, sheet metal. The sheet metal may be covered by a layer of heat insulating material to avoid heat loss.

[0025] The exhaust gas receiver preferably extends along the entire length of the engine (in a direction perpendicular to the axis of the cylinder) and preferably receives exhaust gas from all cylinders via an independent exhaust duct extending into the exhaust gas receiver.

[0026] The exhaust system further includes an exhaust gas treatment unit having at least one exhaust gas cooler, preferably three exhaust gas coolers.

[0027] Multiple exhaust gas coolers are more effective than a single exhaust gas cooler because condensed water can flow between them due to gravity. Exhaust gas coolers may be of the tubular or finned type. The exhaust gas comes into contact with the fins, and heat from the exhaust gas can be transferred to a cooling medium which may be guided through the tubes.

[0028] The cooler is preferably 500-5000m in total, depending on the size of the engine. 2 It has a large cross-section, which in turn minimizes pressure loss.

[0029] The exhaust treatment unit has a duct system for guiding a cooling medium such as water. The duct system may also have tubing for the exhaust gas cooler.

[0030] The heat from the exhaust gas may be sent to an exhaust gas cooler, or it may be transferred to the outside of the cooler by a cooling medium guided into a duct system.

[0031] The exhaust system has at least one heat exchanger having a first fluid line that is fluidly connected to or connectable to the duct system. The at least one heat exchanger is configured to receive a cooling medium from at least one exhaust gas cooler.

[0032] The heat transferred from the exhaust gas cooler by the cooling medium may be released into the heat exchanger.

[0033] The internal combustion engine may further include a turbocharger having a turbine that drives a compressor located upstream of the intake system.

[0034] The turbine is preferably located upstream of the exhaust treatment unit. The exhaust gas may be led directly from the exhaust gas receiver to the turbine without being treated within the exhaust treatment unit.

[0035] Therefore, preferably, the exhaust gas receiver and the exhaust treatment unit are isolated from each other with respect to pressure and temperature.

[0036] The internal combustion engine may have a cooling medium circuit, which includes a duct system and a first fluid line.

[0037] The cooling medium may be guided through a closed circuit.

[0038] The cooling medium circuit preferably includes a pump. The pump may be located upstream of the heat exchanger and downstream of the exhaust gas cooler. The pump may draw the cooling medium from a duct system and push it into the first fluid line of the heat exchanger.

[0039] In a beneficial embodiment, at least one of the at least one heat exchanger is a gas-mode heat exchanger. The gas-mode heat exchanger has a temperature-temperature

[0040] The temperature-controlled fluid can absorb the heat transferred into the gas-mode heat exchanger by the cooling medium.

[0041] A gas-mode heat exchanger or temperature-controlled fluid line may be part of the LNG vaporization circuit of a fuel gas supply system. The temperature-controlled fluid, such as glycol, may substitute for or support the steam provided by the economizer when the fuel gas is heated.

[0042] At least one of the heat exchangers may be a diesel-mode heat exchanger. The diesel-mode heat exchanger may have a water fluid line configured to receive water from the engine's central cooling circuit.

[0043] Preferably, the internal combustion engine has a gas-mode heat exchanger and a diesel-mode heat exchanger. A gas-mode heat exchanger may be used as long as the engine is gas-powered. If the engine is diesel-powered, a diesel-mode heat exchanger may be used.

[0044] In an advantageous embodiment, the internal combustion engine has an exhaust gas recirculation duct, which is fluidly connected to an exhaust treatment unit and an intake system, and is preferably located on the low-pressure side of the turbocharger.

[0045] The exhaust gas may be diverted from the exhaust line downstream of the turbocharger turbine, resulting in some of the exhaust gas being directed to an exhaust treatment unit, from where it can pass through the turbocharger's compressor and into the intake system.

[0046] The exhaust gas recirculation duct may be part of an EGR system extending between the exhaust gas receiver and the intake system, the EGR system having an exhaust gas treatment unit. The EGR system has an EGR conduit that directs a portion of the exhaust gas from the turbine to the exhaust gas treatment unit, and from there to the intake system via the exhaust gas recirculation duct.

[0047] An internal combustion engine may have a blower within the EGR system, particularly within the exhaust gas recirculation duct.

[0048] Alternatively, the internal combustion engine may have an exhaust gas flow limiting device for setting the exhaust pressure in the exhaust gas recirculation duct.

[0049] Preferably, the exhaust gas flow limiting device is an exhaust gas back pressure valve and has a controllable opening in particular to provide an adaptable back pressure for controlling the exhaust gas recirculation rate. Preferably, the exhaust pressure in the exhaust gas recirculation duct may be set in the range of 5 to 100 millibars.

[0050] The exhaust gas flow limiting device may be located at or near the branching point, with a first portion of the exhaust gas branching off from the exhaust line downstream of the turbocharger turbine, and a second portion being directed to the economizer and / or funnel.

[0051] The exhaust treatment unit may have a water separator, which is preferably located downstream of the exhaust gas cooler. The water separator collects condensed water that flows between exhaust gas coolers that are, for example, at a certain distance, preferably 1 to 3 m, from each other.

[0052] A water separator may also be a water mist catcher.

[0053] The collected water may be purified in a water treatment device before discharge.

[0054] The water separator is designed to produce only a small pressure loss, preferably less than 50 mmWG (corresponding to 0.098 millibars). The flow polarizer may cause droplet separation due to inertia.

[0055] The exhaust treatment unit may preferably have at least one exhaust purification element, such as a scrubber, located upstream of the exhaust gas cooler.

[0056] In beneficial embodiments, the exhaust treatment unit and the exhaust gas receiver are arranged adjacent to each other and preferably share a common frame and / or common housing.

[0057] The exhaust gas receiver unit and the exhaust gas receiver may both have an elongated, hollow body extending in the same direction and / or sharing one common wall.

[0058] Thus, the exhaust system consists of compact and space-saving elements that can be directly mounted on top of the cylinder.

[0059] The exhaust treatment unit may have a control unit.

[0060] The control unit may have at least one output line for regulating the flow of cooling water through at least one heat exchanger, the output line being connected to or connectable to a valve for opening and closing a first fluid line. Thus, the control unit can enable or prevent heat exchange in at least one heat exchanger.

[0061] Preferably, the exhaust treatment unit has a valve for each of the heat exchangers, and the control unit has an output line for controlling each of the valves.

[0062] Therefore, the exhaust treatment unit may be switched from gas mode to diesel mode, for example, by closing a valve that allows the flow of a cooling medium through the first fluid line of the gas mode heat exchanger, and by opening a valve that allows the flow of a cooling medium through the first fluid line of the diesel mode heat exchanger.

[0063] The control unit may further have output lines for setting the back pressure in the exhaust gas recirculation duct, which are connected to or can be connected to an exhaust gas flow limiting device. The control unit can control the EGR rate by positioning the opening of an exhaust gas back pressure valve.

[0064] Preferably, as described above, the objective is achieved by an internal combustion engine equipped with a water removal device having a water separator.

[0065] The internal combustion engine is a large marine engine having at least one cylinder, preferably at least one cylinder having an inner diameter of at least 200 mm. The internal combustion engine is preferably a low-pressure fuel gas engine or a dual-fuel engine.

[0066] An internal combustion engine further comprises an intake system through which scavenging gases are introduced into the cylinders, and an exhaust system through which exhaust gases generated in the cylinders are discharged.

[0067] The exhaust system may include an exhaust gas receiver connected to the cylinder via an exhaust outlet for discharging exhaust gases from the cylinder. Preferably, the exhaust system may further include a cooler upstream of the water removal device.

[0068] The internal combustion engine has a turbocharger which has a turbine that drives a compressor located upstream of the intake system.

[0069] An internal combustion engine has exhaust gas recirculation ducts that are fluidly connected to the exhaust system and the intake system.

[0070] Preferably, the exhaust gas recirculation duct is located on the low-pressure side of the turbocharger, so that the exhaust gas is first guided through the turbocharger's turbine and then through the compressor.

[0071] Alternatively, the high-pressure exhaust gas may be guided through a compressor.

[0072] The water removal device is located in the gas recirculation duct upstream of the turbocharger compressor and adjacent to the compressor.

[0073] Therefore, to reduce the risk of condensed water impacting the impeller, water is removed from the exhaust gas before it enters the compressor.

[0074] Preferably, the dewatering device is positioned adjacent to the compressor, resulting in a short passage between the dewatering device and the compressor, and preventing the exhaust from reabsorbing moisture.

[0075] The dehumidification device may be positioned to dehumidify the exhaust gas before mixing it with fresh air.

[0076] The exhaust gas can first come into contact with fresh air in the compressor, where it is mixed with the fresh air. Alternatively, a dehumidifier may be placed upstream of the compressor, so that the dehumidified exhaust gas merges with the fresh air and is then introduced into the compressor together with the fresh air.

[0077] The internal combustion engine may also have a separate dewatering device for fresh air.

[0078] The dewatering device has a water separator for collecting mist and / or water. The dewatering device may have further components to improve the efficiency of removing water and particulate matter.

[0079] The water removal device may be arranged such that the discharge direction of the water removal device is in the axial direction or radial direction of the compressor.

[0080] By positioning the outlet in the axial direction, a compact design becomes possible.

[0081] The water removal device may have heating and / or cooling elements. Preferably, the water separator has an efficiency that corresponds to a specific volumetric flow rate. There may be a need to remove residual water droplets not collected by the water separator.

[0082] Water mist removal can be improved by vaporizing residual water droplets. This can be achieved by cooling the exhaust on the upstream side of the water separator and / or heating the exhaust on the downstream side of the water separator.

[0083] Therefore, all the water can be reliably removed before the exhaust gas enters the compressor.

[0084] The heating element may be an electric heating element.

[0085] The heating element may have a conduit for introducing a temperature-regulating fluid such as water or gas.

[0086] The heating and / or cooling elements may preferably have a closed conduit system for guiding a temperature-controlled fluid that absorbs heat upstream of the water separator and releases heat downstream of the water separator.

[0087] The conduit system may be connected to a duct system for guiding the cooling medium for the exhaust gas cooler, or to a heat exchanger as described above. The heat exchanger may have a temperature-controlled fluid line configured to guide a temperature-controlled fluid for heating the exhaust gas downstream of the water separator.

[0088] The heating element may also use microwaves, infrared waves, and / or heat pumps.

[0089] The water removal device may have a channel for separating water from exhaust gas by gravity and / or centrifugal force.

[0090] The flow path can be positioned perpendicular to the direction of gravity, resulting in exhaust gases being guided horizontally and removed water flowing out vertically.

[0091] The flow path may be curved, and as a result, the exhaust gases are guided along the curved path. Entrained water may be blown radially outward by centrifugal force and separated from the exhaust gases.

[0092] Preferably, as described above, the objective can also be achieved by an exhaust system for an internal combustion engine. The exhaust system comprises an exhaust treatment unit with at least one exhaust gas cooler and an exhaust gas receiver. The exhaust treatment unit and the exhaust gas receiver are arranged adjacent to each other and preferably share a common frame and / or a common housing.

[0093] The exhaust treatment unit may have a duct system for guiding a cooling medium, which may be connectable to at least one heat exchanger.

[0094] The exhaust system may form a space-saving unit that can be directly mounted as a single component to multiple cylinders.

[0095] The objective can also be achieved by a method of operating an internal combustion engine having at least one cylinder. Preferably, the internal combustion engine is a large marine engine having at least one cylinder having an inner diameter of at least 200 mm, preferably a low-pressure fuel gas engine or dual-fuel engine having a cylinder having at least one gas inlet valve for injecting low-pressure fuel gas directly into the cylinder through the cylinder wall and an exhaust outlet for discharging exhaust gas, preferably an internal combustion engine as described above.

[0096] This method includes the following steps:

[0097] The exhaust gases are cooled in at least one exhaust gas cooler that operates with a cooling medium such as water.

[0098] The cooling medium is guided through at least one heat exchanger, in which the heat of the cooling medium is transferred to a temperature-regulating fluid, particularly glycol, for heating the fuel gas, or to water in the engine's central cooling circuit.

[0099] The exhaust gas may be recirculated into the cylinder.

[0100] In particular, the exhaust gas is led from the exhaust gas receiver to the turbocharger turbine, and from the exhaust gas cooler to the turbocharger compressor. More preferably, the exhaust gas is led from the turbocharger turbine to the exhaust gas cooler.

[0101] The present invention will be further described below with reference to the drawings in the following examples. [Brief explanation of the drawing]

[0102] [Figure 1] This is a side view showing an internal combustion engine. [Figure 2] This is a schematic diagram of a cylinder. [Figure 3] This is a schematic diagram of the first example of an internal combustion engine according to the present invention. [Figure 4] This is a schematic diagram of a second example of an internal combustion engine according to the present invention. [Figure 5] This is a schematic diagram of a third example of an internal combustion engine according to the present invention. [Figure 6a] This is a schematic diagram of the first arrangement of the water removal device. [Figure 6b] This is a schematic diagram of the second arrangement of the water removal device. [Figure 7a] This is a schematic diagram of the first example of a water removal device. [Figure 7b] This is a schematic diagram of the second example of a water removal device. [Modes for carrying out the invention]

[0103] Figure 1 shows a side view of the internal combustion engine 100. The internal combustion engine 100 is a dual-fuel engine for large ships, comprising four cylinders 1 with a bore diameter of at least 200 mm.

[0104] The internal combustion engine 100 has an exhaust system 101 through which exhaust gas generated in the cylinder 1 is discharged.

[0105] The exhaust system 101 includes an exhaust gas receiver 4 connected to the cylinder 1 via an exhaust outlet 25 for discharging exhaust gas from the cylinder 1, and an exhaust treatment unit 5.

[0106] Figure 2 is a schematic diagram of cylinder 1. Cylinder 1 has two gas inlet valves 24 for injecting low-pressure fuel gas directly into cylinder 1 through the cylinder wall 2.

[0107] Scavenging air can enter cylinder 1 from the intake system 3 through scavenging ports 27 in the cylinder wall 2. Exhaust gas can be discharged from cylinder 1 through exhaust outlet 25. An exhaust valve 26 is located within the exhaust outlet 25.

[0108] The piston 32 is mounted inside the cylinder 1 so as to be able to reciprocate.

[0109] Figure 3 is a schematic diagram of the first example of the internal combustion engine 100.

[0110] The internal combustion engine 100 has an exhaust system 101 into which exhaust gases generated in the cylinder 1 (see Figures 1 and 2) are directed. The exhaust gas receiver 4 is connected to the cylinder 1 via an exhaust outlet 25 (see Figures 1 and 2).

[0111] The exhaust treatment unit 5 is positioned adjacent to the exhaust gas receiver 4 on a common frame 20 and within a common housing 21.

[0112] The exhaust treatment unit 5 has three exhaust gas coolers 6 arranged in a series. The exhaust treatment unit 5 also has an exhaust purification element 19 positioned upstream of the exhaust gas coolers 6 with respect to the flow direction F of the exhaust gas within the exhaust treatment unit 5.

[0113] The exhaust treatment unit 5 further includes a water separator 18 downstream of the cooler 6. The water separated in the water separator 18 can be purified in the water treatment device 30.

[0114] The exhaust gas is directed from the exhaust gas receiver 4 through the exhaust line 28 to the turbine 9 of the turbocharger 8, which drives the compressor 10 of the turbocharger 8. A portion of the exhaust gas is branched off and guided through the exhaust treatment unit 5, where it is recirculated into the cylinder 1. In the exhaust treatment unit 5, the exhaust gas is purified within the exhaust purification element 19, for example by arranging a water spray. The exhaust gas is then cooled in the exhaust gas cooler 6 and guided through the exhaust gas recirculation duct 16 to the compressor 10 of the turbocharger 8 and the intake system 3. Upstream of the compressor 10, the exhaust gas is mixed with fresh air.

[0115] The pressure in the exhaust gas recirculation duct 16 may be set by the exhaust gas back pressure valve 17. Exhaust gas recirculation can be prevented by closing valves 29 located upstream and downstream of the exhaust treatment unit 5 in the EGR path 33.

[0116] The exhaust system 101 has a duct system 7 for guiding cooling water through the cooling circuit 13. The duct system 7 has tubes (not explicitly shown) that are placed in the cooler 6.

[0117] The duct system is connected to the first fluid line 12a of the gas-mode heat exchanger 11a and to the first fluid line 12b of the diesel-mode heat exchanger 11b, so that cooling water can be guided through the gas-mode heat exchanger 11a and / or the diesel-mode heat exchanger 11b.

[0118] The gas-mode heat exchanger 11a has a temperature-controlled fluid line 15a configured to guide glycol. The glycol is used to heat the fuel gas.

[0119] The diesel mode heat exchanger 11b has a water fluid line 15b configured to guide water to the engine's central cooling circuit. The valve 23a can allow or prevent the flow of the cooling medium from the exhaust treatment unit 5 through the first fluid line 12a of the gas-mode heat exchanger 11a.

[0120] The valve 23b can allow or prevent the flow of the cooling medium from the exhaust treatment unit 5 through the first fluid line 12b of the diesel-mode heat exchanger 11b.

[0121] The cooling circuit 13 has a pump 14 that determines the flow direction of the cooling medium. In the exhaust treatment unit 5, the cooling medium flows in the opposite direction to the exhaust gas flow direction F. The pump 14 is located downstream of the exhaust treatment unit 5 and upstream of the heat exchangers 11a and 11b.

[0122] The exhaust treatment unit 5 has a control unit 22. The control unit 22 has an output line 24a for regulating the flow of cooling water through the gas-mode heat exchanger 11a. The output line 24a is connected to a valve 23a for opening and closing the first fluid line 12a of the gas-mode heat exchanger 11a.

[0123] The control unit 22 further has an output line 24b for regulating the flow of cooling water through the diesel-mode heat exchanger 11b. The output line 24b is connected to a valve 23b for opening and closing the first fluid line 12b of the diesel-mode heat exchanger 11b.

[0124] The control unit 22 is adapted to switch between gas mode and diesel mode, and the cooling medium is led to either a gas mode heat exchanger 11a for heating gas, or a diesel mode heat exchanger 11b where cooling water is cooled by water in the engine's central cooling circuit. The control unit may further have an output line 31 for setting the back pressure valve 17. By opening and closing the back pressure valve 17, the exhaust gas is recirculated into the cylinder 1 to a greater or lesser extent.

[0125] The temperature of the glycol when it enters the gas-mode heat exchanger 11a may be approximately 20°C. The glycol may be heated to 30-35°C inside the gas-mode heat exchanger 11a.

[0126] The temperature of the water in the engine's central cooling circuit when it enters the diesel-mode heat exchanger 11b may be approximately 36°C. The water in the engine's central cooling circuit may be heated to about 5°C or more within the diesel-mode heat exchanger 11b.

[0127] The cooling water may have a temperature of 38-40°C when it enters the exhaust treatment unit. The exhaust gas is cooled from a temperature of 200-280°C to 40-50°C.

[0128] Exhaust gas recirculation reduces the risk of methane slip. When an internal combustion engine is operated in gas mode, that is, when fuel gas is injected directly into cylinder 1, approximately 50% of the exhaust gas is recirculated.

[0129] To stabilize combustion, exhaust gases must be cooled. Introducing hot gases into the cylinder can lead to risks of premature ignition, erratic ignitions, and unwanted pressure fluctuations.

[0130] Figure 4 is a schematic diagram of a second example of the internal combustion engine 100.

[0131] The internal combustion engine 100 further includes a dewatering device 40 having a water separator 18. The dewatering device 40 is located upstream of and next to the compressor 10 to prevent water that may be carried along with the exhaust gas from being introduced into the compressor. Condensate must be avoided as it may cause corrosion or impact to the compressor.

[0132] Figure 5 is a schematic diagram of a third example of an internal combustion engine 100 equipped with cylinder 1.

[0133] The internal combustion engine 100 has an intake system 3 into which scavenging gas is introduced into the cylinder 1. The internal combustion engine 100 has an exhaust system 101 which includes an exhaust gas receiver 4 from which exhaust gas generated in the cylinder 1 is discharged.

[0134] Depending on the settings of valves 34 and 35, exhaust gas may be guided through the turbine 9 of the turbocharger 8 and / or through the bypass pipe 36.

[0135] When valve 37 is open, the exhaust gas recirculation duct 16 is fluidly connected to the exhaust system 101 and the intake system 3.

[0136] The recirculated exhaust gas is guided through a water removal device 40 before entering the compressor 10 of the turbocharger 8.

[0137] Figures 6a and 6b show two possible arrangements of the water removal device 40 relative to the turbocharger 8.

[0138] In the first configuration shown in Figure 6a, the water removal device 40 is positioned so that the outflow direction 38 is the axial direction 39 of the turbocharger 8.

[0139] In the second arrangement shown in Figure 6b, the water removal device 40 is positioned such that the outflow direction 38 is in the radial direction 41 of the turbocharger 8. The water removal device 40 may also be positioned such that the outflow direction 38 is in the tangential direction of the turbocharger 8 (not shown).

[0140] Figure 7a is a schematic diagram of a first example of a water removal device 40.1, which has a flow path 42 that is horizontally and perpendicular to the direction of gravity 43.

[0141] Exhaust gas containing water droplets and particulate matter enters the water removal device 40.1. Condensed water with attached particles is collected in the water mist catcher 18 and can flow out of the water removal device 40.1.

[0142] Figure 7b is a schematic diagram of a second example of the water removal device 40.2. The water removal device 40.2 has a curved channel 43 that improves the collection of water droplets and particulate matter.

[0143] The entrained water is separated from the exhaust gas by centrifugal force in the radial direction 44. The remaining water droplets with attached particulate matter are collected by the water mist catcher 18 and can flow out of the water removal device 40.2.

[0144] The following examples of various aspects of this disclosure are described below as clauses numbered (1, 2, 3, etc.) for convenience. These are provided as examples and do not limit the scope of the technologies covered. [Clause 1] An internal combustion engine (100) having at least one cylinder (1), preferably a large marine engine having at least one cylinder (1) with an inner diameter of at least 200 mm, preferably a low-pressure fuel gas engine or a dual-fuel engine, The device has a cylinder (1), and the cylinder (1) has at least one gas inlet valve (24) for injecting low-pressure fuel gas directly into the cylinder (1) through the cylinder wall (2). The internal combustion engine (100) includes an intake system (3) from which scavenging gas is introduced into the cylinder (1), An exhaust system (101) through which exhaust gas generated in the cylinder (1) is discharged, and It further possesses, The exhaust system (101) An exhaust gas receiver (4) is connected to the cylinder (1) via an exhaust outlet (25) for discharging exhaust gas from the cylinder (1), An exhaust treatment unit (5) having at least one exhaust gas cooler (6), preferably three exhaust gas coolers (6), and a duct system (7) for guiding a cooling medium such as water. In an internal combustion engine (100) having, An internal combustion engine (100) characterized in that the exhaust system (101) has at least one heat exchanger (11a, 11b), the heat exchanger (11a, 11b) has a first fluid line (12a, 12b) that is fluidly connected to or connectable to the duct system (7), and is configured to receive the cooling medium from the at least one exhaust gas cooler (6). [Clause 2] The internal combustion engine (100) according to Clause 1, further comprising a turbocharger (8) having a turbine (9) located upstream of the exhaust treatment unit (4), the turbocharger (8) driving a compressor (10) located upstream of the intake system (3). [Clause 3] The internal combustion engine (100) according to Clause 1 or 2, having a cooling medium circuit (13) having the duct system (7) and the first fluid lines (12a, 12b), wherein the cooling medium circuit (13) preferably has a pump (14), the pump (14) being located particularly upstream of the heat exchangers (11a, 11b) and downstream of the exhaust gas cooler (6). [Clause 4] An internal combustion engine (100) according to Clause 1, 2, or 3, wherein at least one of the at least one heat exchanger (11a, 11b) is a gas-mode heat exchanger (11a), the gas-mode heat exchanger (11a) having a temperature-controlled fluid line (15a) configured to guide a temperature-controlled fluid, in particular glycol, for heating a fuel gas. [Clause 5] An internal combustion engine (100) according to any one of the at least one of the at least one heat exchangers (11a, 11b) is a diesel-mode heat exchanger (11b), the diesel-mode heat exchanger (11b) having a water fluid line (15b) configured to guide water to the engine central cooling circuit. [Clause 6] The internal combustion engine (100) according to any one of the clauses 1 to 5, wherein the internal combustion engine (100) has an exhaust gas recirculation duct (16) that is fluidly connected to an exhaust treatment unit (5) and an intake system (3), and the exhaust gas recirculation duct (16) is preferably located on the low-pressure side of the turbocharger (8). [Clause 7] The internal combustion engine (100) according to Clause 6, having an exhaust gas flow limiting device (17) for setting the exhaust pressure in the exhaust gas recirculation duct (16), preferably the exhaust gas flow limiting device (17) is an exhaust gas back pressure valve, the exhaust gas back pressure valve having a particularly controllable opening that thereby provides a back pressure adaptable to control the exhaust gas recirculation rate, preferably in the range of 5 to 100 millibars. [Clause 8] The exhaust treatment unit (5) preferably has a water separator (18) located downstream of the exhaust gas cooler (6), as described in any one of the clauses 1 to 7, for the internal combustion engine (100). [Clause 9] The exhaust treatment unit (5) preferably has at least one exhaust purification element (19), such as a scrubber, located upstream of the exhaust gas cooler (6), in the internal combustion engine (100) according to any one of the clauses 1 to 8. [Clause 10] The exhaust treatment unit (5) and the exhaust gas receiver (4) are arranged adjacent to each other and preferably share a common frame (20) and / or a common housing (21), in the internal combustion engine (100) according to any one of the clauses 1 to 9. [Clause 11] The internal combustion engine (100) according to any one of the clauses 1 to 10, wherein the exhaust treatment unit (5) has a control unit (22), the control unit (22) has at least one output line (24a, 24b) for regulating the flow of cooling water through at least the heat exchangers (11a, 11b), the output line (24a, 24b) is connected to or connectable to valves (23a, 23b) for opening and closing the first fluid lines (12a, 12b). [Article 12] An internal combustion engine (100) having at least one cylinder (1), preferably an internal combustion engine (100) as described in any of the clauses 1 to 11, preferably a large marine engine having at least one cylinder (1) with an inner diameter of at least 200 mm, preferably a low-pressure fuel gas engine or a dual-fuel engine, The internal combustion engine (100) includes an intake system (3) into which scavenging gas is introduced from the intake system (3) into the cylinder (1), An exhaust system (101) through which exhaust gas generated in the cylinder (1) is discharged, and It further possesses, The internal combustion engine (100) further includes a turbocharger (8) having a turbine (9) that drives a compressor (10) located upstream of the intake system (3), The internal combustion engine (100) has an exhaust gas recirculation duct (16) that is fluidly connected to the exhaust system (101) and the intake system (3), and the exhaust gas recirculation duct (16) is preferably located on the low-pressure side of the turbocharger (8), in the internal combustion engine (100), An internal combustion engine (100) characterized in that a dehumidifying device (40.1, 40.2) having a water separator (18) is located in the gas recirculation duct (16) upstream of the compressor (10) of the turbocharger and adjacent to the compressor (10), thereby allowing the exhaust gas to be dehumidified before being mixed with fresh air. [Clause 13] The internal combustion engine (100) according to Clause 12, wherein the water removal devices (40, 40.1, 40.2) are arranged such that the discharge direction of the water removal devices (40, 40.1, 40.2) is in the axial direction (39) or radial direction (41) of the compressor (10). [Clause 14] The water removal device (40, 40.1, 40.2) is an internal combustion engine (100) as described in Clause 12 or 13, having a heating element. [Article 15] The internal combustion engine (100) according to clause 12, 13, or 14, wherein the water removal device (40, 40.1, 40.2) has a flow path (42, 43) where water is separated from the exhaust gas by gravity and / or centrifugal force. [Clause 16] An exhaust system (101) for an internal combustion engine (100), preferably an exhaust system (101) for an internal combustion engine (100) as described in any one of the clauses 1 to 15, wherein the exhaust system (101) comprises an exhaust treatment unit (5) having at least one exhaust gas cooler (6) and an exhaust gas receiver (4), wherein the exhaust treatment unit (5) and the exhaust gas receiver (4) are arranged adjacent to each other and preferably share a common frame (20) and / or a common housing (21). [Article 17] A method for operating an internal combustion engine (100) having at least one cylinder (1), preferably a large marine engine having at least one cylinder (1) having an inner diameter of at least 200 mm, preferably a low-pressure fuel gas engine or dual-fuel engine having a cylinder having at least one gas inlet valve (24) for injecting low-pressure fuel gas directly into the cylinder (1) through the cylinder wall (2), preferably the internal combustion engine described in any of claims 1 to 11, The steps include cooling the exhaust gas in at least one exhaust gas cooler (6) that operates with a cooling medium such as water, A step of guiding the cooling medium through at least one heat exchanger (11a, 11b) such that the heat of the cooling medium is transferred to a temperature-regulating fluid for heating fuel gas, particularly glycol, or to water in the engine central cooling circuit. A method of operating an internal combustion engine (100), including [the specified part of the engine]. [Clause 18] The method according to claim 13, wherein the exhaust gas is recirculated within the cylinder (1), particularly from the exhaust gas receiver (4) to the turbine (9) of the turbocharger (8), and from the exhaust gas cooler (6) to the compressor (10) of the turbocharger (8).

Claims

1. An internal combustion engine (100) having at least one cylinder (1), that is, a large marine engine having at least one cylinder (1) having an inner diameter of at least 200 mm, The device has a cylinder (1), and the cylinder (1) has at least one gas inlet valve (24) for injecting low-pressure fuel gas directly into the cylinder (1) through the cylinder wall (2). The internal combustion engine (100) includes an intake system (3) from which scavenging gas is introduced into the cylinder (1), An exhaust system (101) through which exhaust gas generated in the cylinder (1) is discharged, and It further possesses, The exhaust system (101) An exhaust gas receiver (4) is connected to the cylinder (1) via an exhaust outlet (25) for discharging exhaust gas from the cylinder (1), An exhaust treatment unit (5) having at least one exhaust gas cooler (6) and a duct system (7) for guiding a cooling medium such as water, In an internal combustion engine (100) having, The exhaust system (101) has at least one heat exchanger (11a, 11b), the heat exchanger (11a, 11b) has a first fluid line (12a, 12b) which is fluidly connected to or connectable to the duct system (7), and is configured to receive the cooling medium from the at least one exhaust gas cooler (6), and An internal combustion engine (100) characterized in that the exhaust treatment unit (5) and the exhaust gas receiver (4) are arranged adjacent to each other and have at least one of a common frame (20) and a common housing (21).

2. The internal combustion engine (100) according to claim 1, further comprising a turbocharger (8) having a turbine (9) located upstream of the exhaust treatment unit (45), the turbocharger (8) driving a compressor (10) located upstream of the intake system (3).

3. The internal combustion engine (100) according to claim 1, wherein the internal combustion engine (100) has a cooling medium circuit (13) having the duct system (7) and the first fluid lines (12a, 12b), and the cooling medium circuit (13) has a pump (14).

4. The internal combustion engine (100) according to claim 1, wherein at least one of the at least one heat exchanger (11a, 11b) is a gas-mode heat exchanger (11a), and the gas-mode heat exchanger (11a) has a temperature-controlled fluid line (15a) configured to guide a temperature-controlled fluid for heating a fuel gas.

5. The internal combustion engine (100) according to claim 1, wherein at least one of the at least one heat exchanger (11a, 11b) is a diesel-mode heat exchanger (11b), and the diesel-mode heat exchanger (11b) has a water fluid line (15b) configured to guide water to the engine central cooling circuit.

6. The internal combustion engine (100) according to claim 1, wherein the internal combustion engine (100) has an exhaust gas recirculation duct (16) that is fluidly connected to the exhaust treatment unit (5) and the intake system (3).

7. The internal combustion engine (100) according to claim 6, wherein the exhaust gas recirculation duct (16) is located on the low-pressure side of the turbocharger (8).

8. The internal combustion engine (100) according to claim 6, wherein the internal combustion engine has an exhaust gas flow limiting device (17) for setting the exhaust pressure in the exhaust gas recirculation duct (16), preferably the exhaust gas flow limiting device (17) is an exhaust gas back pressure valve, thereby providing a back pressure adaptable to control the exhaust gas recirculation rate.

9. The internal combustion engine (100) according to claim 1, wherein the exhaust treatment unit (5) has a water separator (18) located downstream of the exhaust gas cooler (6).

10. The internal combustion engine (100) according to claim 1, wherein the exhaust treatment unit (5) has at least one exhaust purification element (19).

11. The internal combustion engine (100) according to claim 1, wherein the exhaust treatment unit (5) has a control unit (22), the control unit (22) has at least one output line (24a, 24b) for regulating the flow of cooling water through at least the heat exchangers (11a, 11b), the output line (24a, 24b) is connected to or connectable to valves (23a, 23b) for opening and closing the first fluid lines (12a, 12b).

12. An internal combustion engine (100) according to claim 1, The internal combustion engine (100) further includes a turbocharger (8) having a turbine (9) that drives a compressor (10) located upstream of the intake system (3), The internal combustion engine (100) has an exhaust gas recirculation duct (16) that is fluidly connected to the exhaust system (101) and the intake system (3), An internal combustion engine (100) characterized in that a water removal device (40.1, 40.2) having a water separator (18) is arranged in the gas recirculation duct (16) upstream of the compressor (10) of the turbocharger and adjacent to the compressor (10), thereby allowing the exhaust gas to be dehumidified before being mixed with fresh air.

13. The internal combustion engine (100) according to claim 11, wherein the water removal devices (40, 40.1, 40.2) are arranged such that the discharge direction of the water removal devices (40, 40.1, 40.2) is in the axial direction (39) or radial direction (41) of the compressor (10).

14. The water removal device (40, 40.1, 40.2) has a heating element, the internal combustion engine (100) according to claim 11.

15. The internal combustion engine (100) according to claim 11, wherein the water removal device (40, 40.1, 40.2) has a flow path (42, 43) where water is separated from the exhaust gas by at least one of gravity and centrifugal force.

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