Internal combustion engine, exhaust system and method for operating an internal combustion engine

Abstract

The invention relates to an internal combustion engine (100), an exhaust system (101) and a method for operating an internal combustion engine (100). The internal combustion engine (100) has at least one cylinder (1). The internal combustion engine (100) comprises an intake system (3) and an exhaust system (101). The exhaust system (101) comprises an exhaust receiver (4) which is connected to the cylinder (1) via an exhaust port (25) for discharging exhaust gases from the cylinder (1) and an exhaust treatment unit (5) which comprises at least one exhaust cooler (6) and which comprises a conduit system (7) for guiding a cooling medium, such as water. The exhaust system (101) comprises at least one heat exchanger (11a, 11b) which comprises a first fluid line (12a, 12b) which is fluidically connected or fluidically connectable to the conduit system (7) and which is configured to receive the cooling medium from the at least one exhaust cooler (6).

Description

Technical Field

[0001] This invention relates to an internal combustion engine, an exhaust system, and a method for operating an internal combustion engine.

[0002] This invention preferably relates to an internal combustion engine, such as a large marine engine or stationary engine with an inner diameter of at least 200 mm, similar to a cylinder. The engine is preferably a two-stroke engine or a two-stroke crosshead engine. The engine can be a gas-fueled engine, a dual-fuel engine, or a multi-fuel engine. In such engines, combustion of liquid and / or gaseous fuels, as well as auto-ignition or forced ignition, are possible. Background Technology

[0003] An internal combustion engine can be a longitudinally flushing two-stroke engine.

[0004] The term "internal combustion engine" also refers to a large engine that can operate not only in Diesel mode but also in Otto mode or a combination of both. Diesel mode is characterized by the auto-ignition of fuel, while Otto mode is characterized by the active ignition of fuel. Furthermore, the term "internal combustion engine" specifically includes dual-fuel engines and large engines in which the auto-ignition of one fuel is used for the active ignition of another fuel.

[0005] The engine speed is preferably below 800 RPM (especially for four-stroke engines), more preferably below 200 RPM (especially for two-stroke engines), which indicates a low-speed engine.

[0006] The fuel can be diesel or marine diesel or heavy fuel oil or emulsion or slurry or methanol or ethanol, as well as gaseous fuels such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG).

[0007] Other possible fuels that can be added upon request are: LBG (liquefied biogas), biofuels (e.g., oil made from algae or seaweed), ammonia, hydrogen, and synthetic fuels derived from CO2 (e.g., made from electro-gas or electro-liquid).

[0008] Large vessels—especially those used for transporting cargo—are often powered by internal combustion engines—particularly diesel and / or gas-fueled engines (primarily two-stroke crosshead engines). In cases where the engine burns liquid fuels such as heavy fuel oil, marine diesel, diesel, or other liquids, and in cases where the engine burns gaseous fuels such as LNG, LPG, or other similar gases, the exhaust gases from this combustion process need to be purified to comply with existing regulations such as IMO Tier III.

[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 EP 3 722 572A1. For combustion stability, it is advantageous to cool the recirculated exhaust gas.

[0010] Turbocharger compressors are susceptible to damage and corrosion from moisture in exhaust gas. CN112628033A proposes an EGR system with a condensation separation component and a mixer. However, the possibilities for arranging this system are limited because exhaust gas and fresh air are mixed and water is removed.

[0011] US 10,054,085B2 discloses a power system including an EGR cooler, which may be a single-stage or two-stage heat exchanger. The heat used to vaporize the fuel for the power system can be provided by the heat exchanger. Exhaust gas must be directed through the heat exchanger.

[0012] Typically, low-pressure EGR solutions require additional space in the engine compartment. Furthermore, low-pressure EGR solutions result in lower exhaust enthalpy after the engine, leading to lower steam levels. This reduction in steam volume can cause problems for standard exhaust economizers. Summary of the Invention

[0013] The purpose of this invention is to avoid the disadvantages of the prior art, and in particular to provide an internal combustion engine, an exhaust treatment unit, and a method for operating the internal combustion engine that requires reduced space while providing stable combustion without sacrificing enthalpy, wherein, preferably, the adverse effects of condensation are prevented.

[0014] The 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 an inner diameter of at least 200 mm, the large marine engine being preferably a low-pressure fuel gas engine or a dual-fuel engine.

[0015] At least one cylinder has at least one intake valve for injecting low-pressure fuel gas directly into the cylinder through the cylinder wall.

[0016] At least one cylinder has at least one exhaust port. An exhaust valve may be installed in the exhaust port.

[0017] An internal combustion engine also includes an intake system, from which scavenging air is introduced into the cylinder.

[0018] The intake system may include a pipe that is fluidly connected to the intake port of the cylinder.

[0019] The intake system may include a scavenging receiver. Before entering the scavenging receiver, the gas may be guided through a scavenging cooler. Scavenging gas may enter the cylinder via scavenging ports in the cylinder wall.

[0020] An internal combustion engine also includes an exhaust system through which exhaust gases produced in the cylinders are discharged. The exhaust system includes an exhaust receiver connected to the cylinders via an exhaust port for discharging exhaust gases from the cylinders.

[0021] The exhaust port of the cylinder can be connected to an exhaust duct leading to an exhaust receiver, wherein, for example, the exhaust from more than one cylinder is collected in the exhaust receiver.

[0022] The exhaust receiver preferably has, for example, an elongated hollow cylinder made of a metal sheet. The metal sheet may be covered with a layer of insulating material to prevent heat loss.

[0023] The exhaust receiver extends along the length of the engine (preferably the entire length) in a direction perpendicular to the cylinder axis, and preferably receives exhaust from all cylinders via a separate exhaust duct extending into the exhaust receiver.

[0024] The exhaust system also includes an exhaust treatment unit, which includes at least one exhaust cooler, preferably three exhaust coolers.

[0025] Multiple exhaust coolers are more efficient than a single exhaust cooler because condensate is drained away between the exhaust coolers due to gravity.

[0026] Exhaust coolers can be either duct or finned. The exhaust can contact the fins, and heat from the exhaust can be transferred to a cooling medium that can be guided in the duct.

[0027] Depending on the size of the engine, the cooler may include a large cross-section, preferably 500-5000 mm in total. 2 This allows the pressure drop to be kept to a minimum.

[0028] The exhaust treatment unit includes a duct system for guiding a cooling medium such as water. The duct system may include pipes for an exhaust cooler.

[0029] Heat from the exhaust can be delivered to an exhaust cooler and then removed from the cooler via a cooling medium guided through a duct system.

[0030] The exhaust system includes at least one heat exchanger, which includes a first fluid line that is fluidly connected to or can be fluidly connected to a duct system. The at least one heat exchanger is configured to receive cooling medium from at least one exhaust cooler.

[0031] The heat transferred from the exhaust cooler by the cooling medium can be released into the heat exchanger.

[0032] The internal combustion engine may also include a turbocharger, which has a turbine that drives a compressor located upstream of the intake system.

[0033] The turbine is preferably located upstream of the exhaust treatment unit. Exhaust gas can be guided directly from the exhaust receiver to the turbine without being treated in the exhaust treatment unit.

[0034] Therefore, preferably, the exhaust receiver and the exhaust treatment unit are different from each other in terms of pressure and temperature.

[0035] An internal combustion engine may include a cooling medium circuit, which includes a duct system and a first fluid line.

[0036] The cooling medium can be guided through a closed circuit.

[0037] The cooling medium circuit preferably includes a pump. The pump may be located upstream of the heat exchanger and downstream of the exhaust cooler. The pump can draw the cooling medium from the duct system and can also push the cooling medium into the first fluid line of the heat exchanger.

[0038] In an advantageous embodiment, at least one of the heat exchangers is a gas-mode heat exchanger. The gas-mode heat exchanger includes a tempering fluid line configured to guide a tempering fluid (particularly ethylene glycol) for heating the fuel gas.

[0039] The tempering fluid can absorb the heat transferred to the gas-mode heat exchanger through the cooling medium.

[0040] A gas-mode heat exchanger or tempering fluid line can be part of the LNG vaporization loop of a fuel gas supply system. When the fuel gas is heated, the tempering fluid (e.g., ethylene glycol) can replace or support the steam supplied by the economizer.

[0041] At least one of the heat exchangers may be a diesel-mode heat exchanger. The diesel-mode heat exchanger may include a water flow line configured to receive water from the engine's central cooling circuit.

[0042] Preferably, the internal combustion engine includes a gas-mode heat exchanger and a diesel-mode heat exchanger. A gas-mode heat exchanger can be used whenever the engine is gas-driven. A diesel-mode heat exchanger can be used when the engine is diesel-driven.

[0043] In an advantageous embodiment, the internal combustion engine includes an exhaust recirculation duct that is fluidly connected to the exhaust treatment unit and the intake system, the exhaust recirculation duct being preferably arranged on the low-pressure side of the turbocharger.

[0044] The exhaust can branch off from the exhaust line downstream of the turbocharger's turbine, allowing a portion of the exhaust to be directed to the exhaust treatment unit and from there to the intake system via the turbocharger's compressor.

[0045] The exhaust gas recirculation duct can be a portion of an EGR system, including an exhaust treatment unit, that extends between the exhaust receiver and the intake system. The EGR system has an EGR duct that directs a portion of the exhaust gas from the turbocharger to the exhaust treatment unit, and from there via the exhaust gas recirculation duct to the intake system.

[0046] The internal combustion engine may include a blower in the exhaust gas recirculation duct, specifically in the EGR system.

[0047] Alternatively, the internal combustion engine may include an exhaust flow limiting device for setting the exhaust pressure in the exhaust recirculation duct.

[0048] Preferably, the exhaust flow limiting device is an exhaust back pressure valve to provide an adaptive back pressure for controlling the exhaust recirculation rate, and the exhaust back pressure valve specifically includes a controllable opening. Preferably, the exhaust pressure in the exhaust recirculation duct can be set in the range of 5 to 100 mbar.

[0049] The exhaust flow limiting device may be arranged at or near the branch point, where a first portion of the exhaust gas branches off from the exhaust line downstream of the turbocharger turbine and a second portion is directed to the economizer and / or the chimney.

[0050] The exhaust treatment unit may include a water separator, which is preferably located downstream of the exhaust cooler. The water separator collects, for example, condensate discharged between exhaust coolers that may be some distance apart (preferably 1 to 3 m).

[0051] A water separator can be a water mist collector.

[0052] The collected water can be cleaned in the water treatment system before being discharged.

[0053] The water separator is designed to cause only a small pressure drop, preferably less than 50 mmWG (corresponding to 0.098 mbar). The flow deflector plate can cause water droplet separation due to inertia.

[0054] The exhaust treatment unit may include at least one exhaust cleaning element (e.g., a scrubber), and the at least one exhaust cleaning element is preferably arranged upstream of the exhaust cooler.

[0055] In an advantageous embodiment, the exhaust treatment unit and the exhaust receiver are arranged adjacent to each other, preferably comprising a common frame and / or a common housing.

[0056] The exhaust treatment unit and the exhaust receiver may both have elongated hollow bodies extending in the same direction and / or may share a common wall.

[0057] Therefore, the exhaust system is a compact and space-saving component that can be directly mounted on the cylinder.

[0058] The exhaust treatment unit may include a control unit.

[0059] The control unit may include at least one output line for regulating the flow of cooling water through at least one heat exchanger, the at least one output line being connected to or connectable to a valve for opening or closing a first fluid line. Therefore, the control unit may allow or prevent heat exchange in at least one heat exchanger.

[0060] Preferably, the exhaust treatment unit includes valves for each heat exchanger, and the control unit includes output lines for controlling each valve.

[0061] Therefore, the exhaust treatment unit can switch from gas mode to diesel mode, for example, by closing a valve that allows cooling medium to flow through the first fluid line of the gas mode heat exchanger and by opening a valve that allows cooling medium to flow through the first fluid line of the diesel mode heat exchanger.

[0062] The control unit may also include an output line for setting the back pressure in the exhaust gas recirculation duct, which is connected to or can be connected to an exhaust gas flow limiting device. The control unit can control the EGR rate by setting the opening degree of the exhaust gas back pressure valve.

[0063] This objective is achieved by an internal combustion engine, preferably one as described above, which has a water eliminator including a water separator.

[0064] The internal combustion engine has at least one cylinder, preferably a large marine engine with 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.

[0065] An internal combustion engine also includes an intake system and an exhaust system. Scavenging air is introduced into the cylinder from the intake system, and the exhaust gas produced in the cylinder is discharged through the exhaust system.

[0066] The exhaust system may include an exhaust receiver connected to the cylinder via an exhaust port for discharging exhaust gas from the cylinder. The exhaust system may also include a cooler, preferably upstream of the dehydrator.

[0067] An internal combustion engine includes a turbocharger, which has a turbine that drives a compressor located upstream of the intake system.

[0068] An internal combustion engine includes an exhaust recirculation duct that fluidly connects the exhaust system and the intake system.

[0069] Preferably, the exhaust gas recirculation duct is arranged on the low-pressure side of the turbocharger, such that the exhaust gas is first guided through the turbine of the turbocharger and then through the compressor.

[0070] Alternatively, high-pressure exhaust can be directed through a compressor.

[0071] The water separator is located in the exhaust gas recirculation duct, upstream of and adjacent to the compressor of the turbocharger.

[0072] Therefore, removing water from the exhaust before it enters the compressor reduces the risk of the impeller being affected by condensate.

[0073] Preferably, the desiccant is arranged adjacent to the compressor, so that the flow path between the desiccant and the compressor is short and the exhaust gas will not absorb moisture again.

[0074] The dehumidifier can be arranged so that the exhaust gas can be dehumidified before it is mixed with fresh air.

[0075] The exhaust gas comes into initial contact with fresh air in the compressor, and the exhaust gas and fresh air mix within the compressor. Alternatively, a dehumidifier can be located upstream of the compressor, so that the dehumidified exhaust gas merges with the fresh air and is guided to the compressor along with the fresh air.

[0076] Internal combustion engines may also include a separate dehumidifier for fresh air.

[0077] The water separator includes a water separator for capturing mist and / or collecting water. The water separator may also include components for improving the removal efficiency of water and particulate matter.

[0078] The water separator can be arranged such that the water separator flows out in the axial direction of the compressor or in the radial direction of the compressor.

[0079] The outflow arrangement in the axial direction allows for a compact design.

[0080] The water separator may include heating and / or cooling elements.

[0081] Preferably, the water separator has an efficiency corresponding to a specific volumetric flow rate. It may be necessary to remove any residual water droplets not collected by the water separator.

[0082] Water mist elimination can be improved by evaporating the remaining water droplets. This can be achieved by cooling the exhaust gas upstream of the water separator and / or heating the exhaust gas downstream of the water separator.

[0083] Therefore, ensure that all water is removed before the exhaust gas enters the compressor.

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

[0085] Heating elements may include conduits for guiding tempering fluids such as water or gas.

[0086] Heating and / or cooling elements may include preferably enclosed piping systems for guiding tempering fluid that absorbs heat upstream of the water separator and releases heat downstream of the water separator.

[0087] The piping system may be connected to a conduit system for guiding the cooling medium to the exhaust cooler or to a heat exchanger as described above. The heat exchanger may include a tempering fluid line configured to guide tempering fluid for heating the exhaust downstream of the water separator.

[0088] Heating elements may also use microwaves, infrared waves, and / or heat pumps.

[0089] The water separator may include a flow channel in which water is drawn out of the exhaust gas due to gravity and / or centrifugal force.

[0090] The flow channel can be arranged perpendicular to the direction of gravity, so that the exhaust is guided in the horizontal direction and the removed water is discharged vertically.

[0091] The flow channel can be curved, allowing the exhaust gas to be guided along a curved path. The entrained water is driven radially outward by centrifugal force and can separate from the exhaust gas.

[0092] This objective is also achieved by an exhaust system for an internal combustion engine, preferably as described above. The exhaust system includes an exhaust receiver and an exhaust treatment unit having at least one exhaust cooler. The exhaust treatment unit and the exhaust receiver are arranged adjacent to each other, preferably including a common frame and / or a common housing.

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

[0094] The exhaust system can be formed into a space-saving unit that can be directly installed as a component into multiple cylinders.

[0095] This objective is also 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 with an inner diameter of at least 200 mm, preferably a low-pressure fuel gas engine or a dual-fuel engine, the low-pressure fuel gas engine or dual-fuel engine comprising a cylinder having at least one intake valve for directly injecting low-pressure fuel gas through the cylinder wall into the cylinder and an exhaust port for discharging exhaust gas, preferably the internal combustion engine as described above.

[0096] The method includes the following steps:

[0097] The exhaust gas is cooled in at least one exhaust cooler, which operates with a cooling medium such as water.

[0098] The cooling medium is directed through at least one heat exchanger, wherein the heat of the cooling medium is transferred to a tempering fluid (particularly ethylene glycol) to heat the fuel gas, or to water in the engine's central cooling circuit.

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

[0100] Specifically, exhaust gas can be directed from the exhaust receiver to the turbocharger's turbine and from the exhaust cooler to the turbocharger's compressor. More preferably, exhaust gas is directed from the turbocharger's turbine to the exhaust cooler. Attached Figure Description

[0101] The invention will now be further described in the embodiments with reference to the accompanying drawings:

[0102] Figure 1 A side view of an internal combustion engine is shown;

[0103] Figure 2 A schematic diagram of the cylinder is shown;

[0104] Figure 3 A schematic diagram of a first example of an internal combustion engine according to the present invention is shown;

[0105] Figure 4 A schematic diagram of a second example of an internal combustion engine according to the present invention is shown;

[0106] Figure 5 A schematic diagram of a third example of an internal combustion engine according to the present invention is shown;

[0107] Figure 6a A schematic diagram of the first arrangement of the water separator is shown;

[0108] Figure 6b A schematic diagram of a second arrangement of the water separator is shown;

[0109] Figure 7a A schematic diagram of a first example of a water separator is shown;

[0110] Figure 7b A schematic diagram of a second example of a water separator is shown. Detailed Implementation

[0111] Figure 1 A side view of the internal combustion engine 100 is shown.

[0112] The internal combustion engine 100 is a large marine dual-fuel engine with four cylinders 1 having an inner diameter of at least 200 mm.

[0113] The internal combustion engine 100 includes an exhaust system 101 through which exhaust gas generated in the cylinder 1 is discharged.

[0114] The exhaust system 101 includes an exhaust receiver 4 and an exhaust processing unit 5. The exhaust receiver 4 is connected to the cylinder 1 via an exhaust port 25 for discharging exhaust gas from the cylinder 1.

[0115] Figure 2 A schematic diagram of cylinder 1 is shown. Cylinder 1 has two intake valves 24 for injecting low-pressure fuel gas directly into cylinder 1 through cylinder wall 2.

[0116] Scavenging air can enter cylinder 1 from intake system 3 through scavenging port 27 in cylinder wall 2. Exhaust air can be discharged from cylinder 1 through exhaust port 25. Exhaust valve 26 is arranged in exhaust port 25.

[0117] A piston 32 capable of reciprocating motion is installed in cylinder 1.

[0118] Figure 3 A schematic diagram of a first example of an internal combustion engine 100 is shown.

[0119] The internal combustion engine 100 includes an exhaust system 101, in cylinder 1 (see...) Figure 1 and Figure 2 The exhaust gas generated in the process is directed through the exhaust system 101. The exhaust receiver 4 is connected via the exhaust port 25 (see...). Figure 1 and Figure 2 It is connected to cylinder 1.

[0120] The exhaust treatment unit 5 is arranged adjacent to the exhaust receiver 4 on the common frame 20 and in the common housing 21.

[0121] The exhaust treatment unit 5 includes three exhaust coolers 6 arranged in series. The exhaust treatment unit 5 also includes an exhaust cleaning element 19 arranged upstream of the exhaust coolers 6 relative to the exhaust flow direction F in the exhaust treatment unit 5.

[0122] The exhaust treatment unit 5 also includes a water separator 18 downstream of the cooler 6. The water separated in the water separator 18 can be cleaned in the water treatment unit 30.

[0123] Exhaust gas is directed from exhaust receiver 4 through exhaust line 28 to the turbine 9 of turbocharger 8, which drives compressor 10 of turbocharger 8.

[0124] A portion of the exhaust gas is diverted and directed through the exhaust treatment unit 5 for recirculation back into the cylinder 1. In the exhaust treatment unit 5, the exhaust gas is cleaned, for example, by a water spray device in the exhaust cleaning element 19. The exhaust gas is then cooled in the exhaust cooler 6 and directed 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 mixes with fresh air.

[0125] The pressure in the exhaust recirculation duct 16 can be set via the exhaust back pressure valve 17. Exhaust recirculation can be prevented by closing valves 29 located upstream and downstream of the exhaust treatment unit 5 in the EGR path 33.

[0126] The exhaust system 101 includes a conduit system 7 for guiding cooling water through the cooling circuit 13. The conduit system 7 includes pipes (not explicitly shown) arranged in the cooler 6.

[0127] The conduit system is connected to the first fluid line 12a of the gas mode heat exchanger 11a and 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.

[0128] The gas-mode heat exchanger 11a includes a tempering fluid line 15a configured to guide ethylene glycol, which is used to heat the fuel gas.

[0129] The diesel mode heat exchanger 11b includes a water flow line 15b, which is configured to guide water into the engine's central cooling circuit.

[0130] Valve 23a may allow or prevent the flow of cooling medium from the exhaust treatment unit 5 through the first fluid line 12a of the gas mode heat exchanger 11a.

[0131] Valve 23b may allow or prevent the flow of cooling medium from exhaust treatment unit 5 through the first fluid line 12b of diesel mode heat exchanger 11b.

[0132] Cooling circuit 13 includes pump 14, which determines the flow direction of the cooling medium. In exhaust treatment unit 5, the cooling medium flows in the opposite direction to the exhaust flow direction F. Pump 14 is arranged downstream of exhaust treatment unit 5 and upstream of heat exchangers 11a and 11b.

[0133] The exhaust treatment unit 5 includes a control unit 22. The control unit 22 includes 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 or closing a first fluid line 12a of the gas-mode heat exchanger 11a.

[0134] The control unit 22 also includes 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 or closing the first fluid line 12b of the diesel mode heat exchanger 11b.

[0135] The control unit 22 is adapted to switch between gas mode and diesel mode, wherein the cooling medium is either directed to the gas mode heat exchanger 11a to heat the gas or directed to the diesel mode heat exchanger 11b, wherein the cooling water is cooled by the water in the engine central cooling circuit.

[0136] The control unit may have additional output lines 31 for setting the back pressure valve 17. By opening or closing the back pressure valve 17, more or less exhaust gas is recirculated into the cylinder 1.

[0137] The temperature at which ethylene glycol enters the gas-mode heat exchanger 11a can be approximately 20°C. Ethylene glycol can be heated in the gas-mode heat exchanger 11a up to 30-35°C.

[0138] The water in the engine central cooling circuit can reach a temperature of approximately 36°C when it enters the diesel mode heat exchanger 11b. The water in the engine central cooling circuit can be heated by approximately 5°C or higher in the diesel mode heat exchanger 11b.

[0139] The temperature of the cooling water entering the exhaust treatment unit can be 38-40℃.

[0140] The exhaust gas is cooled from a temperature of 200℃-280℃ to a temperature of 40℃-50℃.

[0141] Exhaust gas recirculation reduces the risk of methane escape. When the internal combustion engine operates in gas mode, that is, when fuel gas is injected directly into cylinder 1, approximately 50% of the exhaust gas is recirculated.

[0142] For stable combustion, exhaust gas must be cooled. Allowing hot gas into the cylinder poses risks of pre-ignition, unstable ignition, and unwanted pressure fluctuations.

[0143] Figure 4 A schematic diagram of a second example of an internal combustion engine 100 is shown.

[0144] The internal combustion engine 100 further includes a water separator 40 with a water separator 18. The water separator 40 is arranged upstream of the compressor 10, immediately adjacent to the compressor 10, and prevents water that may be entrained in the exhaust gas from being introduced into the compressor. Condensate can corrode or affect the compressor and should therefore be avoided.

[0145] Figure 5 A schematic diagram of a third example of an internal combustion engine 100 having cylinder 1 is shown.

[0146] The internal combustion engine 100 has an intake system 3, from which scavenging air is introduced into the cylinder 1.

[0147] The internal combustion engine 100 has an exhaust system 101 including an exhaust receiver 4, through which exhaust gas generated in the cylinder 1 is discharged.

[0148] Depending on the settings of valves 34 and 35, exhaust can be directed through the turbine 9 of the turbocharger 8 and / or through bypass 36.

[0149] When valve 37 is open, exhaust recirculation duct 16 is fluidly connected to exhaust system 101 and intake system 3.

[0150] Before the recirculated exhaust gas enters the compressor 10 of the turbocharger 8, it is guided through the dewatering device 40.

[0151] Figure 6a and Figure 6b Two possible arrangements of the water separator 40 relative to the turbocharger 8 are shown.

[0152] exist Figure 6a In the first arrangement shown, the water separator 40 is arranged such that the outflow direction 38 is on the axial direction 39 of the turbocharger 8.

[0153] exist Figure 6b In the second arrangement shown, the water separator 40 is arranged such that the outflow direction 38 is in the radial direction 41 of the turbocharger 8. The water separator 40 may also be arranged such that the outflow direction 38 is in the tangential direction of the turbocharger 8 (not shown in the figure).

[0154] Figure 7a A schematic diagram of a first example of a water separator 40.1 is shown, wherein the water separator 40.1 includes a flow path 42 arranged horizontally and therefore perpendicular to the direction of gravity 43.

[0155] Exhaust gas containing water droplets and particulate matter enters the dewatering device 40.1. Condensate with adhering particles can be collected in the water mist collector 18 and discharged from the dewatering device 40.1.

[0156] Figure 7b A schematic diagram of a second example of a water separator 40.2 is shown. The water separator 40.2 includes a tortuous flow path 43, which improves the collection of water droplets and particulate matter.

[0157] The entrained water is drawn out of the exhaust gas due to centrifugal force in the radial direction 44. The remaining water droplets with attached particulate matter are collected by the water mist collector 18 and can be discharged from the water separator 40.2.

Claims

1. An internal combustion engine (100) having at least one cylinder (1), i.e., a large marine engine having at least one cylinder (1) with an inner diameter of at least 200 mm, said internal combustion engine (100) having a cylinder (1) having at least one intake valve (24) for directly injecting low-pressure fuel gas through the cylinder wall (2) into said cylinder (1), The internal combustion engine (100) also includes: The intake system (3) is used to introduce scavenging air into the cylinder (1); An exhaust system (101) is provided through which exhaust gas generated in the cylinder (1) is discharged. The exhaust system (101) includes: An exhaust receiver (4) is connected to the cylinder (1) via an exhaust port (25) for discharging exhaust gas from the cylinder (1); and An exhaust treatment unit (5) includes at least one exhaust cooler (6) and a duct system (7) for guiding a cooling medium. Its features are, The exhaust system (101) includes at least one heat exchanger (11a, 11b), the at least one heat exchanger (11a, 11b) including a first fluid line (12a, 12b) fluidly connected or fluidly connected to the duct system (7) and configured to receive the cooling medium from the at least one exhaust cooler (6). The internal combustion engine (100) further includes a turbocharger (8) having a turbine (9) that drives a compressor (10) disposed upstream of the intake system (3). The turbine (9) is disposed upstream of the exhaust treatment unit (5). The exhaust treatment unit (5) and the exhaust receiver (4) are arranged adjacent to each other, and the exhaust treatment unit (5) and the exhaust receiver (4) include a common frame (20) and / or a common housing (21).

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

3. 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) including a tempering fluid line (15a) configured to guide tempering fluid for heating fuel gas.

4. The internal combustion engine (100) according to claim 1, wherein, At least one of the at least one heat exchangers (11a, 11b) is a diesel-mode heat exchanger (11b), which includes a water flow line (15b) configured to guide water into the engine's central cooling circuit.

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

6. The internal combustion engine (100) according to claim 5, wherein, The exhaust gas recirculation duct (16) is arranged on the low-pressure side of the turbocharger (8).

7. The internal combustion engine (100) according to claim 5, wherein, The internal combustion engine includes an exhaust flow limiting device (17) for setting the exhaust pressure in the exhaust recirculation duct (16), the exhaust flow limiting device (17) being an exhaust back pressure valve to provide an adaptive back pressure for controlling the exhaust recirculation rate.

8. The internal combustion engine (100) according to claim 1, wherein, The exhaust treatment unit (5) includes a water separator (18) which is arranged downstream of the exhaust cooler (6).

9. The internal combustion engine (100) according to claim 1, wherein, The exhaust treatment unit (5) includes at least one exhaust cleaning element (19).

10. The internal combustion engine (100) according to claim 1, wherein, The exhaust treatment unit (5) includes a control unit (22) which includes at least one output line (24a, 24b) for regulating the flow of cooling water through the at least one heat exchanger (11a, 11b), the at least one output line (24a, 24b) being connected to or capable of being connected to a valve (23a, 23b) for opening or closing the first fluid line (12a, 12b).

11. The internal combustion engine (100) according to claim 1, The internal combustion engine (100) also includes a turbocharger (8) having a turbine (9), which drives a compressor (10) disposed upstream of the intake system (3), and The internal combustion engine (100) includes an exhaust gas recirculation duct (16) that is fluidly connected to the exhaust system (101) and the intake system (3). in, A dehumidifier (40, 40.1, 40.2) including a water separator (18) is arranged in the exhaust gas recirculation duct (16), located upstream and adjacent to the compressor (10) of the turbocharger, so that the exhaust gas can be dehumidified before being mixed with fresh air.

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

13. The internal combustion engine (100) according to claim 11, wherein, The water separator (40, 40.1, 40.2) includes a heating element.

14. The internal combustion engine (100) according to claim 11, wherein, The water separator (40, 40.1, 40.2) includes flow channels (42, 43) in which water is drawn out of the exhaust gas due to at least one of gravity and centrifugal force.

15. A method for operating an internal combustion engine (100) according to claim 1, The method includes the following steps: - The exhaust gas is cooled in at least one exhaust gas cooler (6), said at least one exhaust gas cooler (6) being operated with a cooling medium. - The cooling medium is directed through at least one heat exchanger (11a, 11b), wherein the heat of the cooling medium is transferred to a backfire fluid for heating fuel gas, or the heat of the cooling medium is transferred to water in the engine's central cooling circuit.

16. The method according to claim 15, wherein, The exhaust gas is recirculated into the cylinder (1) and guided from the exhaust receiver (4) to the turbine (9) of the turbocharger (8) and from the exhaust cooler (6) to the compressor (10) of the turbocharger (8).

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