Fuel pressurizing device, engine, and ship

Abstract

Provided is a fuel pressurizing device comprising: a control block for controlling the flow of hydraulic oil supplied from a hydraulic pump; a plurality of pressurizing cylinders for boosting fuel to a high pressure by using the pressure of the hydraulic oil; a control shaft for supplying the hydraulic oil to the plurality of pressurizing cylinders; a housing including a plurality of cylinder seating parts on which the plurality of pressurizing cylinders are seated, respectively, and a shaft seating part on which the control shaft is seated; and a hydraulic motor for rotating the control shaft, wherein the hydraulic motor provides a rotational force by using the pressure of the hydraulic oil supplied from the control block.

Description

Fuel pressurization devices, engines and ships

[0001] The present invention relates to a fuel pressurization device for an engine using low flashpoint fuel, and an engine and a ship equipped with the same.

[0002] Typically, ships are propelled by diesel engines that generate driving force using diesel oil, gas engines that generate driving force using gas such as LNG, and dual fuel engines that generate driving force using a mixture of diesel oil and gas.

[0003] Recently, with the growing demand for eco-friendly / high-efficiency engines due to the strengthening of IMO environmental regulations, research on propulsion systems using various fuels is actively underway.

[0004] Compared to diesel, methanol emits less sulfur oxides (SOx) and particulate matter (PM) during combustion, and also produces relatively low carbon dioxide (CO2) emissions. When produced from biomethanol or renewable feedstocks (carbon dioxide + hydrogen), methanol can achieve carbon neutrality, attracting attention as an eco-friendly fuel.

[0005] Ammonia is attracting attention as an environmentally friendly fuel because it does not contain carbon. Technology for a ship using ammonia as fuel is published in Republic of Korea Patent Publication No. 10-2022-0051098.

[0006] Low flashpoint fuels such as methanol and ammonia have low ignition and combustion rates, requiring a dual-fuel engine system that uses a fuel with high ignition points such as diesel as auxiliary fuel.

[0007] Meanwhile, methanol and ammonia can cause a slip phenomenon in which unburned fuel inside the engine is mixed with the exhaust gas and released into the atmosphere, and are toxic, so a system that takes into account the safety of workers in the event of a leak must be established.

[0008] The present invention is intended to solve the above problems, and an object of the present invention is to provide a fuel pressurization device capable of safely and efficiently pressurizing low flashpoint fuel, and an engine and a ship equipped with the same.

[0009] A fuel pressurization device is provided, comprising: a control block for controlling the flow of hydraulic oil supplied from a hydraulic pump; a plurality of pressurizing cylinders for pressurizing fuel to a high pressure using the pressure of the hydraulic oil; a control shaft for supplying hydraulic oil to the plurality of pressurizing cylinders; a housing including a plurality of cylinder mounting portions on which the plurality of pressurizing cylinders are respectively mounted and a shaft mounting portion on which the control shaft is mounted; and a hydraulic motor for rotating the control shaft, wherein the hydraulic motor provides rotational force using the pressure of the hydraulic oil supplied from the control block.

[0010] The above control block may include a first hydraulic oil line through which hydraulic oil supplied to the control shaft passes and a second hydraulic oil line through which hydraulic oil supplied to the hydraulic motor passes.

[0011] The control block may include a pressure reducing valve positioned on the second hydraulic oil line and reducing the pressure of the hydraulic oil supplied to the hydraulic motor; and a solenoid valve controlling the supply of the reduced pressure hydraulic oil to the hydraulic motor.

[0012] The above control block may include a flow valve that controls the speed of the hydraulic motor by adjusting the flow rate supplied to the hydraulic motor.

[0013] The above control block may include a first oil recovery line for discharging hydraulic oil recovered after driving the hydraulic motor.

[0014] The above first oil recovery line is connected to the solenoid valve and can recover hydraulic oil leaking from the solenoid valve.

[0015] The control block may include a pressure reducing module that reduces hydraulic oil pressure and generates lubricating oil or sealing oil to be supplied to the pressurized cylinder, and the control block may include a second hydraulic oil line that supplies the hydraulic oil to the pressure reducing module.

[0016] The above control block may include a hydraulic oil accumulator that buffers pressure fluctuations of hydraulic oil supplied from the hydraulic pump.

[0017] A second oil recovery line for recovering hydraulic oil discharged from the control shaft is included, and the control shaft may include a first shaft path for distributing hydraulic oil supplied from the control block to the plurality of pressurized cylinders and a second shaft path for supplying hydraulic oil recovered after use in the pressurized cylinders to the second oil recovery line.

[0018] The first shaft passage may be formed by penetrating the inside of the control shaft, and the second shaft passage may be formed on the outer surface of the control shaft.

[0019] The housing may include an operating oil line connecting one side of the shaft mounting portion and the lower part of the cylinder mounting portion and supplying hydraulic oil to the lower part of the pressurized cylinder; and a pressure compensation line connecting the lower part of the cylinder mounting portion and the other side of the control shaft.

[0020] The above shaft mounting portion may include a buffering space formed around the control shaft, and may include a shaft dynamic leak line that discharges hydraulic oil when the pressure of the buffering space is higher than a reference pressure.

[0021] According to another aspect of the present invention, a fuel pressurization device is provided, comprising: a plurality of pressurization cylinders that pressurize fuel to a high pressure using the pressure of hydraulic oil; a control shaft that supplies hydraulic oil to the plurality of pressurization cylinders; a housing including a plurality of cylinder mounting portions on which the plurality of pressurization cylinders are respectively mounted and a shaft mounting portion on which the control shaft is mounted; a low-pressure fuel line that supplies low-pressure fuel to the pressurization cylinders; and a high-pressure fuel line that discharges the high-pressure fuel pressurized in the pressurization cylinders, wherein the pressurization cylinders include a compression piston that moves linearly in a vertical direction by the pressure of the hydraulic oil; a cylinder tube into which the compression piston is inserted at the lower end; and a compression chamber located between the cylinder tube and the compression piston.

[0022] The pressurized cylinder may include a first check valve positioned between the low-pressure fuel line and the compression chamber; and a second check valve positioned between the compression chamber and the high-pressure fuel line.

[0023] The compression piston may include a piston spring that pressurizes the compression piston in a direction in which it is withdrawn from the cylinder tube, and the cylinder mounting portion may be formed at a portion where the piston spring is arranged, and may include a cylinder dynamic leak line that discharges hydraulic oil at a pressure higher than a reference pressure when the piston spring is compressed.

[0024] It may include a hydraulic sealing ring positioned around the compression piston and in contact with the cylinder mounting portion.

[0025] The compression piston includes a piston passage connecting the low-pressure fuel line and the compression chamber, and the piston passage can be selectively connected to the low-pressure fuel line according to the movement of the compression piston.

[0026] The low-pressure fuel line may connect between a plurality of cylinder mounting portions, and the cylinder mounting portions may include a fuel path connected to the low-pressure fuel line and forming a gap with the cylinder tube.

[0027] A fuel leak line for discharging fuel leaked from the low-pressure fuel line is included, wherein the low-pressure fuel line and the high-pressure fuel line are connected to the inner passage of a double-pipe fuel pipe, and the fuel leak line can be connected to the outer passage of the double-pipe fuel pipe.

[0028] The above low-pressure fuel line connects between multiple cylinder mounting portions,

[0029] The above cylinder mounting portion may include a fuel pass connected to the low-pressure fuel line and forming a gap with the cylinder tube.

[0030] It may include a fuel accumulator connected to the fuel pass and buffering pressure fluctuations of the fuel pass according to movement of the compression piston.

[0031] A fuel leak line for discharging fuel leaked from the low-pressure fuel line is included, wherein the low-pressure fuel line and the high-pressure fuel line are connected to the inner passage of a double-pipe fuel pipe, and the fuel leak line can be connected to the outer passage of the double-pipe fuel pipe.

[0032] The above low-pressure fuel line extends and connects between the plurality of cylinder mounting portions, and the above fuel leak line can be connected to the above low-pressure fuel line.

[0033] The housing may include an operating oil line connecting one side of the shaft mounting portion and the lower part of the cylinder mounting portion and supplying hydraulic oil to the lower part of the pressurized cylinder; and a pressure compensation line connecting the lower part of the cylinder mounting portion and the other side of the control shaft.

[0034] It includes a decompression module that reduces the pressure of the hydraulic oil to generate lubricating oil to be supplied to the compression piston, and the lubricating oil can be supplied to at least one of between the compression piston and the cylinder tube, between the compression piston and the cylinder tube, and between the cylinder tubes.

[0035] According to another aspect of the present invention, a fuel pressurization device is provided, comprising: a plurality of pressurization cylinders that pressurize fuel to a high pressure using the pressure of hydraulic oil; a control shaft that supplies hydraulic oil to the plurality of pressurization cylinders; a housing including a plurality of cylinder mounting portions on which the plurality of pressurization cylinders are respectively mounted and a shaft mounting portion on which the control shaft is mounted; a low-pressure fuel line that supplies low-pressure fuel to the pressurization cylinders; a high-pressure fuel line that discharges high-pressure fuel pressurized from the pressurization cylinders; and a decompression module that decompresses the pressure of the hydraulic oil to generate lubricating oil to be supplied to the pressurization cylinders.

[0036] The device may further include a lubricating oil supply line connecting the decompression module and the pressurizing cylinder, and the decompression module may include a relief port for releasing pressure when the pressure of the lubricating oil supply line increases.

[0037] The pressurized cylinder may include a compression piston that moves in a vertical direction in a linear manner by the pressure of the hydraulic oil; and a cylinder tube into which the compression piston is inserted at the bottom, and the compression piston may include a second piston passage that supplies the lubricating oil to a surface where the cylinder tube and the compression piston come into contact.

[0038] An inner sealing ring is formed on the outer circumference of the compression piston and contacts the inner surface of the cylinder tube, and the inner sealing ring can be positioned lower than the low-pressure fuel line.

[0039] The above pressurized cylinder includes a compression piston that moves linearly in a vertical direction by the pressure of the hydraulic oil; and a cylinder tube into which the compression piston is inserted at the bottom, and the pressure reducing module can supply sealing oil between the cylinder tube and the cylinder mounting portion.

[0040] The low-pressure fuel line and the hydraulic oil line supplying the hydraulic oil are connected to the cylinder mounting portion, and the sealing oil can be supplied to a sealing oil groove located between the hydraulic oil line and the low-pressure fuel line.

[0041] It may include an outer sealing ring positioned around the cylinder tube between the sealing oil groove and the connection portion of the low-pressure fuel line.

[0042] It may include a hydraulic sealing ring positioned around the compression piston and in contact with the cylinder mounting portion.

[0043] A sealing ring is located on the outer circumference of the above pressurized cylinder and is in contact with the cylinder mounting portion, and the sealing ring can be located lower than the low-pressure fuel line.

[0044] The above pressure reducing module can supply the hydraulic oil by reducing its pressure to a pressure higher than the pressure of the fuel supplied to the low-pressure fuel line.

[0045] According to at least one embodiment of the present invention, the engine system according to at least one embodiment of the present invention can shorten the length of a dual pipe for supplying high-pressure fuel by providing a fuel pressurization device within the engine.

[0046] Additionally, the fuel pressurization device of the engine system according to at least one embodiment of the present invention can improve efficiency by using a hydraulic motor.

[0047] In addition, the fuel pressurization device of the present invention can effectively control the hydraulic motor through a control block that controls the hydraulic oil supplied to the hydraulic motor.

[0048] In addition, the fuel pressurization device of the present invention can supply lubricating oil and sealing oil of the fuel pressurization device (120) using hydraulic oil, thereby simplifying the configuration of the pipe connected to the fuel pressurization device.

[0049] In addition, the fuel pressurization device of the present invention can safely discharge leaking hydraulic oil and fuel, thereby improving the performance of the fuel pressurization device.

[0050] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0051] FIG. 1 is a diagram illustrating an engine system according to a first embodiment of the present invention.

[0052] FIG. 2 is a diagram illustrating an engine system according to a second embodiment of the present invention.

[0053] FIG. 3 is a diagram illustrating an engine system according to a third embodiment of the present invention.

[0054] Figure 4 is a conceptual diagram of a fuel pressurization device of the engine system of the present invention.

[0055] Figures 5 and 6 are perspective views illustrating a fuel pressurization device of the engine system of the present invention.

[0056] Figure 7 is a cross-sectional view taken along line AA of Figure 5.

[0057] Fig. 8 is a perspective view showing a control block of a fuel pressurization device of the engine system of the present invention.

[0058] Fig. 9 is a BB cross-sectional view of Fig. 5.

[0059] Fig. 10 is a perspective view showing a control shaft of a fuel pressurization device of the engine system of the present invention.

[0060] Figure 11 is a cross-sectional view CC of Figure 5.

[0061] Fig. 12 is a cross-sectional view showing a pressurizing cylinder of a fuel pressurizing device of the engine system of the present invention.

[0062] Fig. 13 is a cross-sectional view of DD of Fig. 5.

[0063] Figure 14 is a graph showing the opening and closing of the check valve and the movement of the compression piston of the fuel pressurization device of the engine system of the present invention.

[0064] Fig. 15 is a perspective view showing a decompression module of a fuel pressure device of an engine system of the present invention.

[0065] Figure 16 is a drawing showing the flow of lubricating oil and sealing oil of the fuel pressurization device of the engine system of the present invention.

[0066] Figure 17 is a drawing showing a fuel leak line of a fuel pressurization device of the engine system of the present invention.

[0067] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components are given the same reference numbers and redundant descriptions thereof will be omitted.

[0068] The suffixes "module" and "part" used in the following description are assigned or used interchangeably solely for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. Furthermore, when describing the embodiments disclosed herein, if a detailed description of a related known technology is deemed to obscure the gist of the embodiments disclosed herein, the detailed description will be omitted.

[0069] In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0070] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0071] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0072] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0073] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0074] A low-flashpoint fuel engine system (1) refers to a system that operates an engine using fuel other than traditional fuels like heavy oil or diesel. Representative examples of low-flashpoint fuels include ammonia and methanol, which are attracting attention as next-generation, eco-friendly fuels.

[0075] Environmentally friendly fuels such as methanol and ammonia are low-flashpoint fuels with a flashpoint lower than 60℃, which can easily ignite and pose a significant risk in the engine room of a ship. They are also toxic to the human body, so the fuel equipment must be installed in a sealed space that blocks gas emissions. In consideration of corrosiveness, storage tanks and fuel transport pipes must be made of corrosion-resistant materials.

[0076] Dual-fuel technology can be applied to low-flashpoint fuels, utilizing them alongside diesel fuel to enhance combustion efficiency. This relates to an engine system that utilizes methanol or ammonia as fuel, and may additionally include a diesel supply system for supplying diesel.

[0077] The low flash point engine system (1) according to the embodiments will be described in detail with reference to the attached drawings below, and description of overlapping parts will be omitted.

[0078] Figure 1 is a diagram illustrating an engine system according to a first embodiment of the present invention. This diagram depicts piping and equipment such as valves and sensors installed in the piping, and is also called a piping & instrumentation drawing (P&ID).

[0079] The present embodiment includes a methanol engine (10) that uses methanol (CH3OH) as fuel.

[0080] Methanol emits less sulfur oxides (SOx) and particulate matter (PM) when burned, and has relatively low carbon dioxide (CO2) emissions. It can be carbon neutral when produced from biomethanol or renewable raw materials (carbon dioxide + hydrogen).

[0081] Methanol has a high octane rating, excellent knock resistance, and generates less carbon dioxide (CO2) and harmful exhaust gases during combustion, attracting attention as an environmentally friendly fuel.

[0082] Methanol has a lower energy density than gasoline, which results in higher fuel consumption, but can be used in dual-fuel technology, either by mixing it with hydrogen fuel or using it with diesel, to improve fuel efficiency and power output.

[0083] Referring to FIG. 1, the engine system (1) of the present invention may include an engine (10) that obtains propulsion using methanol, a fuel tank (50) for supplying fuel to the engine (10), a fuel supply system (20) (FSS: Fuel Supply System), and a fuel valve train (30) (FVT: Fuel Valve Train).

[0084] Although not shown in the drawing, it may include a control unit that controls each device (110, 120, 130, 140, 151) of the engine (10), the pump and heater of the fuel supply system (20), and the valves (32, 33) of the fuel valve train (30). The control unit may control the engine system (1) based on information detected by a pressure sensor and a liquid detection sensor within the engine system (1).

[0085] Each component can be connected to fuel pipes (L2, L4, L5, L6) through which fuel flows. For safety reasons, the fuel pipes can be double-piped. Since methanol is liquid at room temperature, the methanol inside the fuel pipes (L2, L4, L5, L6) can move in a liquid state.

[0086] The fuel pipe may include a fuel supply pipe (L2) that supplies fuel from a fuel tank to the engine, an injector pipe (L4) that supplies fuel to an injector within the engine, and a fuel discharge pipe (L5) that discharges unused fuel from the injector.

[0087] The fuel discharged from the engine (10) through the fuel discharge pipe (L5) may include a fuel recovery pipe (L6) connecting the engine (10) to the fuel tank (50) to recover the fuel to the fuel tank (50).

[0088] The area where the engine (10) is located must be maintained as a safety area to ensure that the engine (10) operates normally and to protect the engine (10) and surrounding workers from hazards. The safety area may be equipped with a ventilation system consisting of an air inlet (61) and an air outlet (62) to ensure continuous ventilation.

[0089] The ventilation system (61, 62) exhausts heat generated from the engine (10) and generates sufficient airflow so that even if fuel leaks from the engine (10), it can be exhausted to minimize exposure of workers to toxic substances. The ventilation system (61, 62) can be located at the inlet and outlet of the fuel pipe in the safety zone, respectively.

[0090] In order to check whether the engine (10) is operating normally, various sensors such as a temperature sensor, a pressure sensor, and a liquid detection sensor may be included. Since the fuel and operating fluid supplied into the engine's fuel pipe are high-pressure fuel, it is necessary to check whether the fluid pressure is within a set range.

[0091] Pressure sensors (PT11-1, PT11-2, PT12, PT13, PT14-1, PT15) can be placed on the fuel pipe or within each component within the engine.

[0092] Methanol is supplied from a fuel tank (50) storing methanol to a fuel supply system (20), and the fuel supply system (20) may include a fuel pump (25) and a temperature control system (heater / cooler, 6). The fuel pump (25) may pressurize methanol to a pressure of about 7-13 bar so that methanol is supplied to the engine (10).

[0093] Unused methanol can be recovered from the engine (10) to the fuel tank (50) and supplied back to the engine (10). Since the methanol may contain impurities (sludge, fine particles, etc.) during this process, the fuel supply system (20) may include a fuel filter (27) to remove the impurities contained in the methanol. Since methanol is vulnerable to moisture, the fuel filter can also remove moisture.

[0094] A fuel valve train (30) located between a fuel supply system (20) and an engine (10) includes a plurality of valve structures and serves to control the timing at which fuel is supplied to the engine (10). The fuel valve train (30) may include a plurality of solenoid valves (SV32-1, SV32-2, SV32-3, SV33) and a sensor (PT31, PT32) for detecting the pressure inside a fuel supply pipe (L2).

[0095] The fuel valve train (30) may include a double block and bleed valve (32) (DBB Valve: Double Block and Bleed Valve). By arranging the valves (SV32-1, SV32-2) in duplicate, the leakage of methanol supplied to the engine (10) can be blocked. The double block bleed valve (32) is a pair of valves (SV32-1, SV32-2) that are closed by default (NC) and can be opened by applying power.

[0096] A drain line (Drain) may be positioned to discharge methanol between a pair of valves (SV32-1, SV32-2) of the double block bleed valve (32) when both valves (SV32-1, SV32-2) are closed.

[0097] The fuel valve train (30) may include a front-end inert gas supply module (33) including a valve (SV33) that selectively supplies not only fuel but also an inert gas such as nitrogen to the engine (10). The inert gas removes fuel remaining in the fuel pipes (L4, L5) inside the engine (10) when the engine (10) is stopped from running or when maintenance of the engine (10) is required.

[0098] Since the inert gas has low reactivity, it does not react with methanol and methanol can be stably discharged together with the inert gas, and the unburned methanol recovered in this way can be supplied back to the fuel tank (50).

[0099] Fuel supplied from the fuel valve train (30) is supplied to the engine (10), and the interior of the engine (10) may include a fuel pressurization device (120), a hydraulic pump (151), an injector (110), a working oil pump (130), and a safety valve unit (140).

[0100] The fuel pressurization device (120) is a device that supplies fuel to the engine (10) at an appropriate pressure and can pressurize low-pressure fuel into high-pressure fuel.

[0101] The conventional fuel pressurization device (120) was installed in a separate pump room space, far away from the engine (10) room. However, in order to transport pressurized fuel to the engine (10), a long double-pipe structure capable of withstanding the pressure must be connected.

[0102] Depending on the size of the vessel, lengths exceeding 100 meters can increase costs and pose significant risks of pressure loss and leakage during transport. Additional costs arise, such as the need for additional leak detection devices and safety measures to prevent ignition or explosion of leaked gas.

[0103] Accordingly, the engine system (1) of the present invention can improve efficiency and safety by arranging a fuel pressurization device (120) inside the engine (10). The fuel pressurization device (120) can utilize a hydraulic booster pump (HBU) that uses hydraulic pressure.

[0104] The hydraulic booster pump is equipped with a solenoid valve for selectively supplying hydraulic oil, and can be selectively driven by an electric signal. A hydraulic booster pump that can be electrically controlled in this way is called an e-HBU (electro Hydraulic Booster Pump). The fuel pressurization device (120) can pressurize low-pressure fuel of 7-13 bar supplied from the fuel valve train (30) to a pressure of 400-600 bar and supply it to the injector (110).

[0105] The hydraulic pump (151) supplies high-pressure hydraulic oil to the fuel pressurization device (120), and the fuel pressurization device (120) can pressurize fuel to high pressure using the pressure of the hydraulic oil. The pressure of the hydraulic oil supplied from the hydraulic pump (151) is at the level of 200-320 bar, and the fuel pressurization device (120) can be driven using the pressure.

[0106] The hydraulic oil supplied to the fuel pressurization device (120) can be used for sealing purposes in addition to driving a piston that increases the pressure of the fuel. Considering the pressure of the low-pressure fuel supplied to the fuel pressurization device (120), the high-pressure hydraulic oil supplied from the hydraulic pump (151) can be lowered to 36-45 bar and used as sealing oil.

[0107] In order to control the injector (110) and prevent fuel backflow (seal), operating oil (C&S oil: control and sealing oil) with a pressure corresponding to the high-pressure fuel is required. The operating oil pump (130) supplies high-pressure operating oil to the injector (110), and the operating oil supplied from the operating oil pump (130) can be used as driving and lubricating oil for the injector (110).

[0108] Since the operating fluid must have a pressure equivalent to (or slightly higher than) the pressure of the fuel supplied to the injector (110) to prevent reverse flow of the fuel, when the fuel is supplied to the injector (110) at 400 to 600 bar, the operating fluid can be supplied by pressurizing it at a pressure of 400 to 650 bar.

[0109] The operating oil pump (130) of this embodiment can use a hydraulic booster that pressurizes the operating oil pressure to 400 to 650 bar using high-pressure hydraulic oil supplied from a hydraulic pump (151).

[0110] The engine (10) may further include a fuel discharge line (L5) to discharge unused fuel and residual fuel. Fuel supplied from the fuel pressurization device (120) is branched into an injector pipe (L4) supplied to the injector (110) and a fuel discharge pipe (L5), and the fuel discharge pipe (L5) may include a purge valve (141) that selectively passes fuel.

[0111] The purge valve (141) is included in the safety valve unit (140) (SVU: Safety Valve Unit), and the purge valve (141) is basically in an open state (NO) so that fuel within the engine (10) can be discharged to the fuel recovery pipe (L6). In an operation mode in which fuel is injected from the injector to generate power, the control unit can close the purge valve (141) to block the flow of fuel to the fuel recovery pipe (L6).

[0112] The purge valve (141) must be able to withstand high pressure (400-600 bar) to prevent the passage of high-pressure fuel. Since it is difficult for an electric valve to sufficiently withstand the pressure of high-pressure fuel, a hydraulic valve can be used as the purge valve (141).

[0113] The oil supplied when the purge valve (141) is driven can use hydraulic oil supplied from the hydraulic pump (151). However, as described above, the pressure (200 to 320 bar) of the oil supplied from the hydraulic pump (151) is lower than the pressure (400 to 600 bar) of the fuel pressurized in the fuel pressurization device (120), so the purge valve (141) is made larger in size to prevent the fuel from flowing into the discharge line.

[0114] The purge valve (141) is kept open before fuel is supplied, and when low-pressure fuel is supplied to the engine (10), the purge valve (141) is opened to fill the fuel pipes (L4, L5) inside the engine with fuel before the fuel pressurization device (120) pressurizes it.

[0115] When the fuel pressurization device (120) operates to supply high-pressure hydraulic oil by operating the hydraulic pump (151), the purge valve (141) closes and the high-pressure fuel can be supplied to the injector (110) without being discharged to the fuel recovery pipe (L6).

[0116] At this time, an inert gas such as nitrogen may be supplied to the rear end of the purge valve (141) to recover the fuel remaining at the rear end of the purge valve (141). The safety valve unit (140) may include an inert gas supply valve that supplies the inert gas in addition to the purge valve (141). The inert gas supply valve may be composed of multiple valves to prevent backflow.

[0117] Since the inert gas does not react with methanol, the fuel remaining in the recovery pipe (L6) at the rear end of the purge valve (141) can be pushed out and returned to the fuel tank (50). The recovery pipe (L6) can be connected from the engine (10) to the fuel tank (50).

[0118] When the engine (10) is stopped from running, the fuel supply system (20) stops the operation of the pump (25) and the double block bleed valve (32) of the fuel valve train (30) also closes, thereby stopping the fuel supply to the engine (10). The purge valve (141) of the engine (10) is opened to discharge the fuel inside the engine (10) and allow it to be recovered to the fuel tank (50) through the fuel recovery pipe (L6).

[0119] Since the injector (110) and the fuel pressure device (120) also stop operating, the hydraulic pump (151) and the operating oil pump (130) can also lower the oil pressure to prevent the operating oil from flowing back.

[0120] Since liquid methanol may remain, the fuel valve train (30) includes an inert gas supply line such as nitrogen, and supplies the inert gas to the engine (10) so that all residual inert gas inside the engine (10) can be discharged.

[0121] In the drawing, only the structure of the engine (10) connected to the fuel supply pipe (L4, L5) through which fuel is supplied is shown, and the engine (10) may include an engine block in which fuel supplied from an injector (110) is burned, an intake and combustion system, an exhaust system, a cooling system, etc.

[0122] Fig. 2 is a diagram illustrating an engine system according to a second embodiment of the present invention. The engine system (1) and fuel supply system (20) of the aforementioned embodiment and the fuel valve train (30) of the engine system (2) according to the second embodiment are identical, but the configuration within the engine (10) is different.

[0123] The operating oil pump (130) that supplies operating oil to the injector (110) is a device for pressurizing the operating oil. In the embodiment of Fig. 1, the operating oil pump (130) uses a hydraulic booster. Since the hydraulic booster operates using hydraulic oil, a pipe is required to supply high-pressure hydraulic oil to the operating oil pump (130), and it is large in volume.

[0124] In the case of the fuel pressurization device (120), a hydraulic booster is efficient because a large amount of fuel is pressurized, but the amount of operating oil supplied to the injector is relatively small, so the operating oil pump (130) can be changed to an electric oil pump to pressurize and use only a small amount of operating oil. By changing the operating oil pump (130) from a hydraulic drive type to an electric oil pump, the hydraulic pipe connecting the hydraulic pump (151) to the operating oil pump (130) can be omitted, and the size of the operating oil pump (130) can be reduced.

[0125] The embodiment of Fig. 1 is driven by supplying hydraulic oil for the operation of the purge valve (141) from a hydraulic pump (151). The operation of the fuel pressurization device (120), the operating oil of the injector, and the operation of the purge valve (141) can all be supplied through the hydraulic oil pump (151), thereby simplifying the configuration.

[0126] However, the pressure of the oil supplied from the hydraulic pump (151) is lower than the high pressure fuel pressure blocked by the purge valve (141), so there is a limit to reducing the purge valve (141).

[0127] Meanwhile, the embodiment of FIG. 2 can receive high-pressure oil for the operation of the purge valve (141) from the operating oil pump (130) rather than the hydraulic pump (151). The operating oil pump (130) pressurizes the operating oil to 450 to 650 bar so that it has a pressure equivalent to or higher than the high-pressure fuel supplied to the injector (110).

[0128] The purge valve (141) of the second embodiment can control the flow of fuel using oil at a pressure more than twice that of the aforementioned embodiment, thereby reducing the volume of the purge valve (141). The purge valve (141) is opened when filling fuel into the fuel pipe before driving the engine (10) or when purging the fuel inside the engine (10) after driving the engine (10) is completed, and the purge valve (141) is closed when driving the engine (10) to block the exhaust line.

[0129] Purging is a process of removing fuel inside the fuel pipe (L4, L5) of the engine. It refers to a step of injecting an inert gas such as nitrogen into the fuel pipe (L4, L5) of the engine and opening the purge valve (41) to discharge the fuel.

[0130] When the engine (10) is running, the operating oil pump (130) supplies high-pressure (450 to 650 bar) operating oil to the injector (110) and also supplies high-pressure operating oil to the purge valve (141) to close the purge valve (141) and block the discharge line.

[0131] However, even in the step of filling fuel into the engine (10) before driving the engine (10) with the purge valve (141) open (fuel filling step), if low-pressure fuel still exists inside the engine (10) immediately after the engine (10) is stopped (pressure reduction step), low-pressure operating fluid (15 to 50 bar) must be supplied to the injector (110).

[0132] The safety valve unit (140) may further include a working oil valve (SV145) positioned between the working oil pump (130) and the purge valve (141) to drive the purge valve (141) independently from the injector (110). The working oil valve (SV145) may employ an electrically driven solenoid valve. The working oil valve (SV145) can selectively supply working oil, so that even if the working oil pump (130) is driven to supply working oil to the injector (110), the supply to the purge valve (141) can be blocked to keep the purge valve (141) in an open state.

[0133] A fuel pressurization device (120) is a device that compresses low-pressure fuel to high-pressure by pushing a plunger with hydraulic oil. The hydraulic oil supplied to the plunger is periodically supplied and recovered, and may include a motor that manages this cycle.

[0134] Motors can be either servo or hydraulic. Servomotors utilize an electrically driven shaft that allows precise control of rotation angle, speed, and position, and offer rapid response. However, their torque (force) is weak, requiring expensive equipment to achieve sufficient torque, increasing costs.

[0135] A hydraulic motor can rotate a shaft using hydraulic oil. Compared to a servo motor, a hydraulic motor has lower precision but can produce high torque. Furthermore, the fuel pressurization device (120) of the present invention receives high-pressure hydraulic oil, which can be used to drive the hydraulic motor.

[0136] The engine system (1) according to the first embodiment of FIG. 1 illustrates an embodiment that uses a servo motor to drive the shaft of a fuel pressurization device (120), and the engine system (2) according to the second embodiment of FIG. 2 can reduce costs by using a hydraulic motor to drive the shaft of a fuel pressurization device (120).

[0137] FIG. 3 is a diagram illustrating an ammonia engine system (3) according to a third embodiment of the present invention.

[0138] This embodiment is an ammonia engine system (3) using ammonia as fuel. Ammonia (NH3) can be used as a fuel in place of existing fossil fuels and is attracting attention as a next-generation eco-friendly fuel because it does not contain carbon. However, it has a low self-ignition capacity, making it difficult to ignite, and contains toxic substances that are harmful to the human body if leaked.

[0139] The methanol engine (10) is a dual fuel engine (10) in which diesel is partially used due to combustion safety issues, similar to ammonia, and has something in common in that it has a system that takes into account the safety of workers in the event of a fuel leak, as the fuel contains toxicity.

[0140] Therefore, the engine (10) of the methanol engine system (2) according to the second embodiment of FIG. 2 can be directly applied to the engine (10) of the ammonia engine system (3) according to the first embodiment of FIG. 3. The same engine (10) can be applied to both the methanol engine system (2) and the ammonia engine system (3), thereby improving manufacturing efficiency.

[0141] However, since ammonia has a high ignition point and is in a gaseous state at room temperature, it must be maintained under high pressure to maintain a liquid state. Ammonia supplied to the engine through the fuel pressurization device (120) also differs from methanol in that it has a higher pressure of 50-83 bar than methanol.

[0142] By controlling the pressure of the sealing oil (hydraulic oil) of the fuel pressurization device (120) and the sealing oil (operating oil) of the injector (110) to match the pressure of ammonia, the engine (10) of the present embodiment can use ammonia as fuel.

[0143] In addition, the purge valve (141) can be controlled independently from the injector (110) through the operating oil valve (SV145), so that the engine (10) of the present embodiment can be applied to the ammonia engine system (3).

[0144] The engine system (3) according to the third embodiment of FIG. 3 is an ammonia engine system (3) that uses ammonia as fuel, and the engine (10) can use the same engine (10) as the embodiment of FIG. 2, but there is a slight difference in the control method.

[0145] Before injecting ammonia, an inert gas of 32-40 bar can be filled in advance into the engine (10) to increase the pressure in the fuel pipes (L4, L5, L6). In order to discharge ammonia in the engine, an inert gas can be supplied from a pre-stage inert gas supply module (33) that supplies an inert gas, and an inert gas of 30 bar or more can be filled into the fuel pipes (L4, L5, L6) at the rear end of the fuel valve train (30). At this time, the operating oil pump (130) and the hydraulic pump (151) can supply operating oil and hydraulic oil as sealing oil to the injector (110) and the fuel pressurization device (120) at a level of 50-70 bar according to the pressure of the inert gas.

[0146] After closing the purge valve (141) and recovering the ammonia at the rear end of the purge valve, in order to prevent the ammonia discharged from the engine from vaporizing, the fuel recovery pipe (L6) can be filled with an inert gas through the rear inert gas supply module (146) to maintain the internal pressure of the fuel recovery pipe (L6) above the ammonia vaporization pressure.

[0147] In the process of lowering the pressure of ammonia inside the engine (10) by terminating the operation of the engine (10), the process can be divided into a step of discharging in a liquid state and a step of discharging in a gaseous state to prevent vaporization of ammonia.

[0148] Even though the engine (10) of the ammonia engine system (3) uses the same engine (10) as the methanol engine system (2), the fuel supply system (20) and the fuel valve train (30) of the front end are different, and there are differences in the specific control method and the pressure of the fuel and operating oil.

[0149] The fuel tank (50) of the engine system (3) of the present embodiment may include a low-pressure fuel pump (51). Ammonia can be converted into a gas at room temperature, so that the ammonia can be pressurized to maintain a liquid state and supplied to the fuel supply system (20).

[0150] The fuel supply system (20) may include a temperature control device (26) to control the temperature so that the ammonia remains in a liquid state, and may include a fuel filter (27) to prevent impurities from entering the engine. Ammonia that is initially pressurized in the low-pressure pump (51) may be re-pressurized in the high-pressure pump (25) of the fuel supply system (20) so that ammonia of 50-83 bar can be supplied to the engine (10).

[0151] The fuel supply system (20) of the ammonia engine system (3) can recover ammonia in a gaseous state and can be recovered mixed with an inert gas during purging. Unlike the methanol engine system, the ammonia engine system does not directly recover the recovered ammonia into the ammonia fuel tank (50), but can be equipped with a separate recovery device (21, 22, 23) to process the recovered ammonia so that it can be reused.

[0152] It may include a knockout drum (21) (KOD: Knock Out Drum) for recovering ammonia converted to a gaseous state. The knockout drum (21) is also called a gas-liquid separator and can separate gaseous ammonia and liquid ammonia.

[0153] The knockout drum (21) can be connected to the fuel valve train (31, 36) and can recover vaporized ammonia from the fuel pipe to the vent line (391, 392a, 392b) to prevent the vaporized ammonia from being supplied to or leaked from the engine (10).

[0154] The knockout drum (21) has a wider space than the fuel pipe, and the ammonia in the gaseous and liquid states that moves into the knockout drum (21) has a slower flow rate. Inside the knockout drum (21), the liquid ammonia falls to the bottom due to gravity, and the gaseous ammonia is supplied to the exhaust gas treatment device (80) to remove toxicity and be discharged. The liquid ammonia is collected in a recovery tank (22) and can be recycled.

[0155] Ammonia can be converted to a gaseous state when the pressure is lowered when supplied to an empty fuel pipe. Therefore, the ammonia engine system (3) can be filled with an inert gas before supplying ammonia to the fuel pipes (L4, L5) of the engine (10). Alternatively, after the engine (10) is stopped from operating, the fuel recovery pipe (L6) can be filled with an inert gas to prevent the ammonia inside the engine from being vaporized due to a lower pressure when moving to the fuel recovery pipe (L6).

[0156] Since the ammonia that is unburned and recovered in the engine (10) may contain an inert gas, the fuel supply system (20) may further include an inert gas / fuel separator (23) that separates the inert gas from the recovered ammonia. The liquid ammonia and the inert gas are primarily separated in the inert gas / fuel separator (23), and the gaseous fuel mixed with the inert gas can be secondarily recovered in the knockout drum (21).

[0157] The fuel valve train (31, 36) of the ammonia engine system (3) may also include a valve train (36) at the rear end of the engine (10). The valve train located at the front end of the engine (10) is called a supply valve train (31) (SVT: Supply Valve Train), and the valve train located at the rear end of the engine (10) is called a return valve train (36) (RVT: Return Valve Train).

[0158] The supply valve train (31) and the return valve train (36) of the fuel valve train (31, 36) can be configured as a single module and can have a left-right symmetrical structure. The fuel supply pipe (L2) of the supply valve train (31) and the fuel return pipe (L6) on the return valve train (36) can be arranged horizontally adjacent to each other.

[0159] The supply valve train (31) may have a configuration similar to the fuel valve train (30) of the aforementioned methanol engine system (2). The double-block bleed valve (32) can block ammonia supplied to the engine (10), thereby isolating the engine (10) and the fuel supply system (20).

[0160] The double block bleed valve (32) includes a vent line (392b) located between a pair of valves, and the methanol engine (10) recovers liquid methanol through the vent line (392b), but the double block bleed valve (32) of the ammonia engine system (3) is connected to a knockout drum (21) where ammonia can be converted into a gaseous state.

[0161] The supply valve train (31) may include a pre-stage inert gas supply module (33) that supplies an inert gas such as nitrogen. The pre-stage inert gas supply module (33) may include a high-pressure inert gas supply valve (33a) that supplies a high-pressure inert gas and a low-pressure inert gas supply valve (33b) that supplies a low-pressure inert gas. Since ammonia is easily vaporized under low pressure, a high-pressure inert gas is required to recover liquid ammonia, and thus a high-pressure inert gas can be supplied through the high-pressure inert gas supply valve (33a). The low-pressure inert gas supply valve (33b) can supply a lower-pressure inert gas than the inert gas supplied by the high-pressure inert gas supply valve (33a) to recover gaseous ammonia.

[0162] The ammonia engine system (3) can be filled with an inert gas (inert gas padding) before supplying ammonia to the engine (10). To prevent ammonia from vaporizing in a vacuum, the pressure of the fuel pipe within the engine (10) can be configured to be 30 bar or higher.

[0163] A return line can be closed via a return valve train (36) at the rear end of the engine (10) to allow the fuel pipes (L4, L5) inside the engine (10) to be filled with an inert gas. The return valve train (36) also includes a double-block bleed valve (37) that isolates the fuel supply system (20) and the engine (10), and a gas recovery line (392a) between a pair of valves (SV37-1, SV37-2) can be connected to a knockout drum (21).

[0164] To distinguish between the double block bleed valve (32) of the supply valve train (31) and the double block bleed valve (37) of the return valve train (36), the former is called the supply valve (32) and the latter is called the return valve (37).

[0165] The return valve train (36) can optionally supply fuel to the inert gas / fuel separator (23) or the knockout drum (21) depending on the condition of the recovered fuel. Basically, since the engine is filled with an inert gas to maintain a high pressure state, the return valve train (36) can supply fuel to the inert gas / fuel separator (23).

[0166] When the engine is shut down, the remaining fuel after the liquid fuel is recovered becomes gaseous, and the gaseous ammonia can be recovered to the knockout drum (21) through the vent line (391). In particular, in an emergency stop situation, the ammonia inside the engine (10) can be diverted to the knockout drum (21) to quickly discharge it.

[0167] As shown in Fig. 3, the return valve train (36) is provided with a plurality of vent lines (391) bypassing the knockout drum (21) to quickly recover gaseous ammonia within the engine (10).

[0168] Fig. 4 is a conceptual diagram of a fuel pressurization device (120) of an engine system of the present invention. The fuel pressurization device (120) of the present invention is located within the engine (10) and compresses low-pressure fuel into high-pressure fuel and supplies it to the injector (110), and is applicable to both the second and third embodiments described above.

[0169] By providing a fuel pressurization device (120) within the engine (10), the length of the double pipe for transporting high-pressure fuel can be shortened, and the stability of the overall engine system can be improved.

[0170] The fuel pressurized in the fuel pressurization device (120) of the present invention may include methanol or ammonia. The fuel pressurization device (120) applied to the methanol engine system (2) can pressurize low-pressure methanol of 17-13 bar into high-pressure methanol of 400-600 bar.

[0171] The fuel pressurization device (120) applied to the ammonia engine system (3) can pressurize low-pressure ammonia of 50-83 bar into high-pressure ammonia of 400-600 bar. Since ammonia vaporizes at room temperature, it can be supplied to the fuel pressurization device (120) at a higher pressure than methanol to prevent ammonia from vaporizing.

[0172] The fuel pressurization device (120) of the present invention may include a control block (122), a pressurization cylinder (126), a control shaft (125), a housing (128), and a hydraulic motor (124). The housing (128) may include a cylinder mounting portion (1286) in which the pressurization cylinder (126) is mounted, and a shaft mounting portion (1285) in which the control shaft (125) is mounted.

[0173] The pressurized cylinder (126) can compress fuel to a high pressure of 400-600 bar using high pressure hydraulic oil of 200-320 bar, and may include a cylinder tube (1267) in which fuel is received and a compression piston (1261) inserted into the lower part of the cylinder tube (1267).

[0174] The control shaft (125) includes a shaft path on the outer surface and the inner surface through which hydraulic oil flows. The control shaft (125) rotates to supply and recover hydraulic oil to the pressure cylinder (126), and the compression piston (1261) of the pressure cylinder (126) moves up and down in accordance with the rotational speed of the control shaft (125) to pressurize fuel.

[0175] A hydraulic motor (124) is a motor that rotates using the pressure of hydraulic oil. Compared to a servo motor that rotates using electric power, it is difficult to precisely control, but it is inexpensive and can obtain high output. In particular, since the fuel pressurization device (120) of the present invention receives high-pressure hydraulic oil from a hydraulic pump, it can drive the hydraulic motor (124) using this.

[0176] The control block (122) includes a plurality of branched hydraulic oil lines and can control the flow and pressure of hydraulic oil supplied from the hydraulic pump to supply it to the control shaft (125) or the hydraulic motor (124).

[0177] The first hydraulic oil line (1211) can supply high-pressure hydraulic oil supplied from a hydraulic pump to a pressurized cylinder (126), and the second hydraulic oil line (1212) can supply hydraulic oil at a lower pressure than the hydraulic oil of the first hydraulic oil line (1211) to a hydraulic motor (124).

[0178] Since the pressure supplied from the hydraulic pump (151) is too high to be directly used by the hydraulic motor (124), the second hydraulic oil line (1212) may include a pressure reducing valve to lower the pressure of the hydraulic oil. In addition, the second hydraulic oil line (1212) may include a solenoid valve to selectively open and close the second hydraulic oil line (1212) to selectively control the operation of the hydraulic motor.

[0179] The hydraulic motor (124) may include a flow control valve that controls the amount of hydraulic oil supplied to the hydraulic motor (124) as it is determined by the amount of hydraulic oil supplied to the hydraulic pump (151). The hydraulic oil supplied to the hydraulic motor (124) (referred to as motor oil for convenience of explanation) provides driving force to the hydraulic motor (124) to rotate the control shaft (125) and then may be returned to the control block (122).

[0180] The control block (122) may include a first oil recovery line (1231) for discharging motor oil recovered from the hydraulic motor (124). The first oil recovery line (1231) may also recover hydraulic oil leaked from components within the control block (122), such as a solenoid valve.

[0181] When hydraulic oil is supplied to the lower portion of the compression piston (1261) of the pressure cylinder (126), fuel supplied to the compression chamber located above the compression piston (1261) is compressed to high pressure and, when it reaches a predetermined pressure (400-600 bar), is discharged to the high-pressure fuel line (1284) so ​​that it can be supplied to the injector (110) of the engine (10).

[0182] Both fuel and hydraulic oil are supplied to the pressurized cylinder (126), and if the two fluids mix, the performance of the fuel pressurized device (120) may deteriorate. To prevent backflow of fuel, sealing oil may be supplied to the pressurized cylinder (126).

[0183] The sealing oil has a pressure greater than that of the fuel supplied to the low-pressure fuel line (1281) (17-13 bar for methanol, 50-83 bar for ammonia). For example, the fuel pressurization device (120) of a methanol engine (10) requires sealing oil of 35-45 bar, and ammonia requires sealing oil of 80-120 bar.

[0184] The fuel pressurization device (120) of the present invention can use hydraulic oil supplied from a hydraulic pump (151) as sealing oil. However, if the hydraulic oil supplied from the hydraulic pump (151) is used as sealing oil at 200 bar or higher, the sealing oil may leak in the direction of the fuel.

[0185] A pressure reducing module (127) may be provided to convert a portion of the high-pressure hydraulic oil into low-pressure sealing oil. The pressure reducing module (127) reduces the hydraulic oil from 200-320 bar to 80-120 bar and supplies it to the pressurizing cylinder (126).

[0186] The hydraulic oil decompressed in the decompressor module (127) can be used as sealing oil or as lubricating oil to reduce friction of the compression piston (1261). The decompressor module (127) can supply the decompressed hydraulic oil between the cylinder tube (1267) of the pressure cylinder (126) and the cylinder mounting portion (1286), between the compression piston (1261) and the cylinder tube (1267), and between the compression piston (1261) and the cylinder mounting portion (1286).

[0187] The sealing oil prevents the fuel and hydraulic oil from mixing, while at the same time allowing the compression piston (1261) to move, so it can also act as a lubricant.

[0188] In the filling step of filling the engine (10) with low-pressure fuel before driving the engine (10), the fuel pressurizing device (120) does not pressurize the fuel, but the fuel injected into the engine (10) passes through the fuel pressurizing device (120).

[0189] At this time, sealing oil is required because fuel may flow backward in the pressurizing cylinder (126) of the fuel pressurizing device (120). That is, although the hydraulic motor (124) is not driven, the hydraulic pump (151) may supply hydraulic oil to the fuel pressurizing device (120) for sealing oil. At this time, the hydraulic oil supplied by the hydraulic pump (151) is used for sealing purposes, and the pressure of the hydraulic oil supplied by the hydraulic pump (151) may be lower than the pressure of the hydraulic oil (200-320 bar) as the working fluid for pressurizing the fuel, which is 50-70 bar.

[0190] The control shaft (125) sequentially supplies hydraulic oil to a plurality of pressure cylinders (126) while rotating, and the hydraulic oil moves the compression piston (1261) of the pressure cylinders (126), thereby pressurizing the fuel.

[0191] The specific structure and operation will be examined in more detail with reference to the drawings below.

[0192] FIG. 5 and FIG. 6 are perspective views illustrating a fuel pressurization device (120) of the engine system of the present invention, and FIG. 7 is a cross-sectional view taken along line AA of FIG. 5.

[0193] The housing (128) forms the exterior of the fuel pressurization device (120) and may include a cylinder mounting portion (1286) in which a plurality of pressurization cylinders (126) are mounted, a shaft mounting portion (1285) in which a control shaft (125) is mounted, and a low-pressure fuel line (1281) and a high-pressure fuel line (1284) that supply low-pressure fuel connected to the cylinder mounting portion (1286). The low-pressure fuel line (1281) and the high-pressure fuel line (1284) may be connected to a plurality of cylinder tubes (1267).

[0194] The fuel pipe of the engine (10) can be connected to a low-pressure fuel line (1281) and a high-pressure fuel line (1284). Fuel and inert gas introduced into the fuel pipe of the engine (10) can pass through the low-pressure fuel line (1281) and the high-pressure fuel line (1284).

[0195] The cylinder mounting portion (1286) includes a cylindrical space extending vertically, and a plurality of such spaces may extend horizontally. A low-pressure fuel line (1281) may be connected to the side of the cylinder mounting portion (1286), and a high-pressure fuel line (1284) may be connected to the top of the cylinder mounting portion (1286).

[0196] The shaft mounting portion (1285) is located below the cylinder mounting portion (1286) and can be connected to a plurality of cylinder mounting portions (1286). A hydraulic motor (124) can be connected to one side of the shaft mounting portion (1285), and the hydraulic motor (124) can rotate the control shaft (125) within the shaft mounting portion (1285).

[0197] A control block (122) is coupled to one side of the housing (128), and the control block (122) may include a first hydraulic oil line (1211) that supplies hydraulic oil to a shaft mounting portion (1285) and a second hydraulic oil line (1212) that supplies hydraulic oil to a hydraulic motor (124).

[0198] FIG. 8 is a perspective view showing a control block (122) of a fuel pressurization device (120) of the engine system of the present invention, and FIG. 9 is a BB cross-sectional view of FIG. 5.

[0199] Hydraulic oil is supplied to one side of the control block (122), and the hydraulic oil is supplied to the control shaft (125) located at the shaft mounting portion (1285) through the first hydraulic oil line (1211). The control shaft (125) rotates and supplies hydraulic oil to the pressure cylinder (126) at a predetermined cycle.

[0200] The hydraulic oil flow may not be continuous, resulting in pulsation. To address the backflow caused by pulsation or an imbalance in the hydraulic oil supply, the control block (122) may include a hydraulic oil accumulator (1215) connected to the hydraulic oil line. The hydraulic oil accumulator (1215) is an elastic bag filled with an inert gas such as nitrogen, and assists in maintaining a constant flow of hydraulic oil.

[0201] Hydraulic oil may leak between the control block (122) and the housing (128), and the leaked hydraulic oil may be recovered through the leak line (1216) to the hydraulic oil inlet (1210) and reused.

[0202] The hydraulic oil supplied to the hydraulic motor (124) is branched to a second hydraulic oil line (1212), and the second hydraulic oil line (1212) may include a pressure reducing valve (1223) that reduces the pressure of the hydraulic oil to a pressure available to the hydraulic motor (124).

[0203] Even if the fuel pressurization device (120) does not generate high-pressure fuel, such as in the step of filling fuel before driving the engine (10), hydraulic oil may be supplied as sealing oil to prevent reverse flow of fuel as the fuel passes through the fuel pressurization device (120). A solenoid valve (1225) may be included to selectively supply hydraulic oil to the hydraulic motor (124).

[0204] The speed of the hydraulic motor (124) can be controlled through a flow control valve (1227) that controls the amount of hydraulic oil supplied to the hydraulic motor (124). The second hydraulic oil line (1212) supplies motor oil to the hydraulic motor (124) through a motor oil supply line (1241). The motor oil can be returned to the control block (122) through a motor oil return line (1242) after providing rotational power to the motor in the hydraulic motor (124).

[0205] The control block (122) may include a first oil recovery line (1231) for discharging recovered motor oil. The first oil recovery line (1231) may also collect and recover hydraulic oil leaked on the second hydraulic oil line (1212), such as a solenoid valve (1225).

[0206] Fig. 10 is a perspective view of a control shaft (125) of a fuel pressurization device (120) of an engine system of the present invention, and Fig. 11 is a CC cross-sectional view of Fig. 4.

[0207] Hydraulic oil supplied to the control shaft (125) can move along a shaft path formed on the control shaft (125). The shaft path may include a first shaft path (1251) that supplies hydraulic oil supplied from the control block (122) to a plurality of pressurizing cylinders (126).

[0208] The first shaft path (1251) may include a distribution path (1254) formed axially long inside the control shaft (125) and may include an input path (1252) and an output path (1255) extending radially from the distribution path (1254).

[0209] The input path (1252) is a path through which hydraulic oil supplied from the first hydraulic oil path (121) of the control block (120) flows. The input path (1252) may include an input external path (1252a) formed in a ring shape on the outer circumference of the control shaft (125) and an input internal path (1252b) extending radially from the input external path (1252a) to the distribution path (1254). A plurality of input internal paths (1252b) may be formed along the circumference of the control shaft (125).

[0210] The output passage (1255) supplies oil to a plurality of pressure cylinders (126), and can be arranged along the length of the control shaft (125) at positions corresponding to the plurality of pressure cylinders (126). The plurality of output passages (1255) have different extended angles, so that hydraulic oil can be sequentially supplied to the plurality of pressure cylinders (126) according to the rotation angle of the control shaft (125).

[0211] Hydraulic oil recovered after pressurizing fuel in the pressurized cylinder (126) can move to the second oil recovery line (1232) through the second shaft passage (1257) formed on the outer surface of the control shaft (125).

[0212] The second shaft oil passage (1257) may include a first portion (1257a) overlapping the position of the pressure cylinder (126) and a second portion (1257b) in a ring shape formed longitudinally adjacent to the first portion (1257a). Hydraulic oil discharged from the pressure cylinder (126) may move from the first portion (1257a) to the second portion (1257b) and then to the second oil return line (1232).

[0213] The first part is positioned at the same position in the longitudinal direction as the output path (1255), and may be positioned spaced apart from the output path (1255) in the circumferential direction. Referring to Fig. 11, the second part of the output path (1255) and the second shaft path (1257) may be positioned at a right angle.

[0214] Referring to Fig. 11, it includes an operating oil line (1287) connected to the lower part of the cylinder mounting portion (1286) on one side of the shaft mounting portion (1285).

[0215] When the output path (1255) of the control shaft (125) and the operating oil line (1287) overlap, hydraulic oil is supplied to the cylinder mounting portion (1286). When the second shaft path (1257) of the control shaft (125) and the operating oil line (1287) overlap, hydraulic oil of the cylinder mounting portion (1286) is supplied to the shaft mounting portion (1285).

[0216] If the pressure of the hydraulic oil supplied to the lower part of the pressurizing cylinder (126) through the operating oil line (1287) is too high, the control shaft (125) is pressed downward, which may result in damage to the control shaft (125).

[0217] By equalizing the pressure above and below the shaft mounting portion (1285), the force that presses the control shaft (125) downward can be eliminated. A pressure compensation line (1288) connecting the lower portion of the cylinder mounting portion (1286) and the other side of the shaft mounting portion (1285) may be further included.

[0218] The pressure compensation line (1288) can be opened when the pressure below the cylinder mounting portion (1286) exceeds the reference pressure, thereby reducing the pressure difference between one side and the other side of the shaft mounting portion (1285).

[0219] One end of the control shaft (125) is connected to the hydraulic motor (124), and if the hydraulic pressure remains in the connection portion (1259) with the hydraulic motor (124), a force is applied in the axial direction, which may affect the operation of the hydraulic motor (124).

[0220] Referring to Fig. 9, the pressure of the hydraulic oil supplied to the control shaft (125) can affect the hydraulic motor (124). The buffering space (1259) formed at a position adjacent to the hydraulic motor of the shaft mounting portion (1285) can buffer the influence of the high-pressure hydraulic oil supplied to the control shaft.

[0221] Since the size of the buffering space (1259) is limited due to the structure of the housing (128), the shaft dynamic leak line (1235) can be connected to discharge the pressure when the pressure of the buffering space (1259) exceeds the reference pressure.

[0222] The dynamic leak line is an emergency route that discharges hydraulic oil that has entered through an abnormal path, preventing hydraulic oil leaks and damage to parts caused by hydraulic oil pressure.

[0223] FIG. 12 is a cross-sectional view showing a pressurizing cylinder (126) of a fuel pressurizing device (120) of the engine system of the present invention, which is a partially enlarged view of FIG. 7.

[0224] A pressurized cylinder (126) mounted on a cylinder mounting portion (1286) may include a cylinder tube (1267) and a compression piston (1261) inserted into the lower portion of the cylinder tube (1267). The cylinder tube (1267) may be connected to a low-pressure fuel line (1281) and a high-pressure fuel line (1284).

[0225] The compression piston (1261) can move up and down inside the cylinder mounting portion (1286) and pressurize fuel introduced into the compression chamber (C) located at the upper portion of the cylinder tube (1267).

[0226] The compression piston (1261) includes a first piston passage (1262a) connecting a low-pressure fuel line (1281) and a compression chamber (C) located above the cylinder tube (1267). The first piston passage (1262a) is selectively connected to the low-pressure fuel line (1281) according to the up-and-down movement of the compression piston (1261), so that low-pressure fuel can be introduced, and the fuel can be supplied to the compression chamber (C) located above the compression piston (1261) through the piston passage (1262a).

[0227] Fig. 13 is a cross-sectional view of DD of Fig. 5, showing the connection between the low-pressure fuel line and the pressurized cylinder.

[0228] The cylinder mounting portion (1286) is spaced apart from the cylinder tube (1267) at a position where it is connected to the low-pressure fuel line (1281), so as to form a fuel path (1285a, see FIGS. 11 and 13) that supplies low-pressure fuel to another adjacent pressurized cylinder (126).

[0229] The low-pressure fuel on the low-pressure fuel line (1281) and the fuel pass (1285a) may pulsate according to the movement of the compression piston (1261), and a fuel accumulator (1282, see FIG. 5) connected to the low-pressure fuel line (1281) may be included to buffer this.

[0230] The lower check valve (1269a) located between the first piston passage (1262a) and the compression chamber (C) opens when the pressure difference between the first piston passage (1262a) and the compression chamber (C) is greater than the reference pressure, allowing fuel to flow in the forward direction (from the first piston passage (1262a) to the compression chamber (C)). The lower check valve (1269a) prevents fuel from flowing backward, so that fuel does not flow backward from the compression chamber (C) to the first piston passage (1262a).

[0231] The compression piston (1261) moves upward due to the pressure of the hydraulic oil flowing into the lower portion of the compression piston (1261) and pressurizes the fuel in the compression chamber (C). The cylinder tube (1267) may further include an upper check valve (1269b) located between the compression chamber (C) and the high-pressure fuel line (1284). The second check valve may open when the second reference pressure is higher than the second reference pressure, so that the fuel in the compression chamber (C) can be supplied to the injector (110) through the high-pressure fuel line (1284).

[0232] Fig. 14 is a graph showing the opening and closing of the check valve of the fuel pressurization device (120) of the engine system of the present invention and the movement of the compression piston (1261). The solid curve is a graph showing the height of the compression piston (1261), the upper horizontal straight line indicates the opening and closing state of the upper check valve (1269b), and the lower horizontal straight line indicates the opening and closing state of the lower check valve (1269a).

[0233] When hydraulic oil is supplied to the lower portion of the compression piston (1261), the compression piston (1261) rises. The fuel in the compression chamber (C) is pressurized, and the pressure in the compression chamber (C) increases, so that the lower check valve (1269a) does not open (Step 1).

[0234] At this time, if the hydraulic oil leaks to the upper side of the pressure cylinder (126), the pressure of the hydraulic oil decreases, so a hydraulic sealing ring (1265e) formed on the outer circumference of the compression piston (1261) and in contact with the cylinder mounting portion (1286) may be included.

[0235] When the compression piston (1261) moves upward, the fuel pressure inside the compression chamber (C) increases, and when the pressure inside the compression chamber (C) reaches the reference pressure (600-650 bar or more), the upper check valve (1269b) opens, allowing the high-pressure fuel inside the compression chamber (C) to be discharged into the high-pressure fuel line (1284) (Step 2).

[0236] After the compression piston (1261) moves to the top of the cylinder tube (1267), the compression piston (1261) may move downward to increase the volume of the compression chamber (C). When the pressure inside the compression chamber (C) decreases, the upper check valve (1269b) closes and the lower check valve (1269a) opens, so that fuel in the low-pressure fuel line (1281) may be filled into the compression chamber (C) (step 3).

[0237] The pressurized cylinder (126) can repeat the above three steps to pressurize the fuel and supply it to the injector (110). The compression piston (1261) can overlap the low-pressure fuel line twice during one up-and-down reciprocating movement, and when descending, the lower check valve (1269a) opens and the fuel moves to the compression chamber (C), but when ascending, the pressure in the compression chamber (C) is high and the lower check valve (1269a) does not open.

[0238] The compression piston (1261) may include a piston spring (1263) to provide a force to move upward and downward again by the pressure of the hydraulic oil. The piston spring (1263) may be positioned between the lower end of the cylinder tube (1267) and the compression piston (1261), and the lower end of the compression piston (1261) may include a spring mounting portion (A) in which the piston spring (1263) is arranged.

[0239] When the piston spring (1263) is compressed, the volume of the spring mounting portion (A) decreases and the pressure of the spring mounting portion (A) increases above the reference pressure, so that a force can be applied in the opposite direction of the force that moves the compression piston (1261) upward.

[0240] The cylinder mounting portion (1286) can control the pressure of the spring mounting portion (A) by forming a cylinder dynamic leakage line (1236) at the portion where the compression spring is located. The cylinder dynamic leakage line (1236) can be connected to the shaft dynamic leakage line (1235) described above and discharged together.

[0241] When hydraulic oil flows into the spring mounting portion (A), the pressure in the spring mounting portion (A) tends to increase. The hydraulic sealing ring (1265e) formed around the compression piston (1261) prevents the hydraulic oil supplied to the lower portion of the compression piston (1261) from flowing upward into the pressure cylinder (126).

[0242] The compression piston (1261) moves up and down while in contact with the side wall of the cylinder mounting portion (1286) or the inner wall of the cylinder tube (1267). Lubricating oil is required to reduce friction of the compression piston (1261).

[0243] Although lubricating oil can be supplied to the fuel pressurizing device (120) through a separate line, the fuel pressurizing device (120) of the present invention can utilize the supplied hydraulic oil as lubricating oil for the compression piston (1261).

[0244] Fig. 15 is a perspective view illustrating a decompression module (127) of a fuel pressurization device (120) of an engine system of the present invention. Fig. 15 is a drawing illustrating the flow of lubricating oil (①) and sealing oil (②) of a fuel pressurization device (120) of an engine system of the present invention.

[0245] A portion of the hydraulic oil may be supplied to a pressure reducing module (127) located on one side of the housing (128). The pressure reducing module (127) includes a pressure reducing valve (1271) that reduces the pressure of high-pressure hydraulic oil, and generates lubricating oil by reducing the pressure of the hydraulic oil supplied from the hydraulic pump (151). Hydraulic oil having a pressure of 200 bar or higher may be supplied to the pressurized cylinder (126) through a lubricating oil supply line (1273) after reducing the pressure to 80-120 bar.

[0246] As illustrated in Fig. 16, the lubricating oil (①) supplied to the pressurized cylinder (126) is supplied between the cylinder tube (1267) and the compression piston (1261). The lubricating oil supplied to the outer surface of the compression piston (1261) can flow into the piston passage formed in the compression piston (1261) and be supplied between the compression piston (1261) and the cylinder tube (1267).

[0247] Lubricating oil supplied from the decompression module (127) is supplied between the compression piston (1261) and the cylinder mounting portion (1286) and between the compression piston (1261) and the cylinder tube (1267) to reduce the frictional force of the compression piston (1261).

[0248] The lubricant supply line (1273) can directly supply lubricant between the compression piston (1261) and the cylinder mounting portion (1286), and can utilize the second piston oil path (1262b) formed in the compression piston (1261) to supply lubricant between the compression piston (1261) and the cylinder tube (1267).

[0249] One end of the second piston oil passage (1262b) may be connected to a lubricating oil supply line (1273) and the other end may be positioned between the compression piston (1261) and the cylinder tube (1267). A lubricating oil groove (1265d) formed around the compression piston (1261) may be further included so that the lubricating oil supplied from the other end of the second piston oil passage (1262b) is supplied to the circumference of the compression piston.

[0250] As the compression piston (1261) moves, a backflow may occur from the cylinder mounting portion (1286) along the lubricating oil supply line (1273) toward the decompression module (127). To prevent pressure from increasing within the decompression module (127), the decompression module (127) may include a relief port (1275, FIG. 14) for discharging the increased pressure.

[0251] The pressurized cylinder (126) may include a sealing ring (1265a, 1265b) to prevent mixing of hydraulic oil and fuel, which may result in unnecessary fuel waste and malfunction of the fuel pressurization device (120).

[0252] Since fuel and hydraulic oil may be mixed as the compression piston (1261) moves inside the cylinder tube (1267), an inner sealing ring (1265b) positioned between the compression piston (1261) and the inner surface of the cylinder tube (1267) may be included. The inner sealing ring (1265b) may be positioned lower than the first piston passage (1262a) that meets the low-pressure fuel line (1281).

[0253] Meanwhile, the lubricating oil in the lubricating oil groove (1265d) can simultaneously function as sealing oil to separate the hydraulic oil and fuel. A pair of inner sealing rings (1265b) are provided above and below the lubricating oil groove (1265d) to prevent the hydraulic oil and fuel from mixing between the compression piston (1261) and the cylinder tube (1267) together with the lubricating oil in the lubricating oil groove (1265d).

[0254] If fuel flows between the cylinder mounting portion (1286) and the cylinder tube (1267) and flows toward the hydraulic oil, the fuel may be wasted unnecessarily. An outer sealing ring (1265b) positioned on the outer periphery of the cylinder tube (1267) and in contact with the cylinder mounting portion (1286) may be included. The outer sealing ring (1265b) may be positioned lower than the low-pressure fuel line (1281).

[0255] To enhance the sealing effect on the outside of the cylinder tube (1267), sealing oil (②) can be supplied adjacent to the outer sealing ring (1265b). The sealing oil can utilize lubricating oil generated in the pressure reducing module (127).

[0256] The 80-120 bar oil generated in the decompression module (127) is supplied to the compression piston (1261) through the lubricating oil supply line (1273) and used as lubricating oil, and can be supplied to the outer surface of the cylinder tube (1267) through the sealing oil supply line (1274) and serve as sealing oil.

[0257] It may include a sealing oil groove (1265c) formed around the cylinder tube (1267) that meets the sealing oil supply line (1274) so ​​that the sealing oil is supplied in a ring shape around the cylinder tube.

[0258] A pair of outer sealing rings (1265b) can be arranged above and below a sealing oil supply line (1274) that supplies sealing oil between a cylinder tube (1267) and a cylinder mounting portion (1286) to separate hydraulic oil and fuel.

[0259] Fig. 17 is a drawing illustrating a fuel leak line (1283) of a fuel pressurization device (120) of an engine system of the present invention. Fuel supplied to the fuel pressurization device (120) passes through a low-pressure fuel line (1281), a cylinder mounting portion (1286), a pressurization cylinder (126), and a high-pressure fuel line (1284).

[0260] Some of the fuel supplied to the pressurized cylinder (126) from the low pressure fuel line (1281) may leak, and the housing (128) may include a fuel leak line (1283) to recover the leaked fuel.

[0261] The fuel leak line (1283) is connected to the end of the low-pressure fuel line (1281) as shown in FIG. 13, and can discharge fuel through the fuel leak line (1283) to protect the fuel pressurization device in an abnormal pressure situation that is difficult to be filled even by the fuel accumulator (1282).

[0262] The fuel leak line (1283) can be connected to the outer passage of a fuel pipe configured as a double tube to collect leaked fuel from each cylinder mounting portion (1286). Since the outer passage is continuously ventilated by supplying air, the fuel collected in the fuel leak line (1283) can be safely discharged.

[0263] Referring to FIGS. 5 and 6, a plurality of holes positioned around the low-pressure fuel line (1281) and the high-pressure fuel line (1284) are ends of the fuel leak line (1283) and can be connected to the outer passage of the fuel pipe having a double-pipe structure. The inner passage of the fuel pipe can be connected to the low-pressure fuel line (1281) and the high-pressure fuel line (1284). As described above, the fuel pressurization device (120) of the present invention can efficiently pressurize fuel using the hydraulic motor (124).

[0264] An engine system according to at least one embodiment of the present invention can shorten the length of a dual pipe for supplying high-pressure fuel by providing a fuel pressurization device within the engine.

[0265] In addition, the fuel pressurization device (120) of the engine system according to at least one embodiment of the present invention can improve efficiency by using a hydraulic motor.

[0266] In addition, the fuel pressurization device (120) of the present invention can effectively control the hydraulic motor (124) through a control block (122) that controls the hydraulic oil supplied to the hydraulic motor (124).

[0267] In addition, the fuel pressurization device (120) of the present invention can supply lubricating oil and sealing oil of the fuel pressurization device (120) using hydraulic oil, thereby simplifying the configuration of the pipe connected to the fuel pressurization device (120).

[0268] In addition, the fuel pressurization device (120) of the present invention can safely discharge leaking hydraulic oil and fuel, thereby improving the performance of the fuel pressurization device (120).

[0269] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are intended to be included within the scope of the present invention.

[0270] With respect to various embodiments for implementing the present invention, duplicate descriptions are omitted as they have been described above in the previous table of contents, Best Mode for Carrying Out the Invention.

[0271] The present invention is applicable to engines and ships in various fields, and thus its industrial applicability is recognized.

Claims

1. A control block that controls the flow of hydraulic oil supplied from a hydraulic pump; A plurality of pressurized cylinders that pressurize fuel to high pressure using the pressure of hydraulic oil; A control shaft for supplying hydraulic oil to the plurality of pressurized cylinders; A housing including a plurality of cylinder mounting portions on which the plurality of pressure cylinders are respectively mounted and a shaft mounting portion on which the control shaft is mounted; and It includes a hydraulic motor that rotates the above control shaft, A fuel pressurization device characterized in that the hydraulic motor provides rotational force by using the pressure of hydraulic oil supplied from the control block.

2. In paragraph 1, The above control block A first hydraulic oil line through which hydraulic oil supplied to the above control shaft passes. A fuel pressurization device characterized by including a second hydraulic oil line through which hydraulic oil supplied to the hydraulic motor passes.

3. In paragraph 2, The above control block A pressure reducing valve located on the second hydraulic oil line and lowering the pressure of the hydraulic oil supplied to the hydraulic motor; and A fuel pressurization device characterized by including a solenoid valve that controls the supply of the depressurized hydraulic oil to the hydraulic motor.

4. In paragraph 3, A fuel pressurization device characterized in that the control block includes a flow valve that controls the speed of the hydraulic motor by adjusting the flow rate supplied to the hydraulic motor.

5. In paragraph 3, The above control block A fuel pressurization device characterized by including a first oil recovery line for discharging hydraulic oil recovered after driving the hydraulic motor.

6. In paragraph 5, A fuel pressurization device characterized in that the first oil return line is connected to the solenoid valve and recovers hydraulic oil leaking from the solenoid valve.

7. In paragraph 1, It includes a decompression module that decompresses hydraulic oil to produce lubricating oil or sealing oil to be supplied to the pressurized cylinder, A fuel pressurization device characterized in that the control block includes a second hydraulic oil line for supplying the hydraulic oil to the decompression module.

8. In paragraph 1, A fuel pressurization device characterized in that the control block includes a hydraulic oil accumulator that buffers pressure fluctuations of hydraulic oil supplied from the hydraulic pump.

9. In paragraph 1, Includes a second oil recovery line for recovering hydraulic oil discharged from the control shaft; The above control shaft A first shaft path for distributing hydraulic oil supplied from the above control block to the plurality of pressurized cylinders; A fuel pressurization device characterized by including a second shaft path for supplying hydraulic oil recovered after use in the pressurized cylinder to the second oil recovery line.

10. In paragraph 9, The above first shaft euro is formed by penetrating the inside of the control shaft, A fuel pressurization device characterized in that the second shaft euro is formed on the outer surface of the control shaft.

11. In paragraph 9, The above housing An operating oil line connecting one side of the shaft mounting portion and the lower part of the cylinder mounting portion and supplying hydraulic oil to the lower part of the pressurized cylinder; and A fuel pressurization device characterized by including a pressure compensation line connecting the lower portion of the cylinder mounting portion and the other side of the control shaft.

12. In paragraph 1, The above shaft mounting portion includes a buffering space formed around the control shaft, A fuel pressurization device characterized by including a shaft dynamic leak line for discharging hydraulic oil when the pressure of the buffering space is higher than a reference pressure.

13. A fuel pressurization device according to any one of paragraphs 1 to 12; and An engine including an injector that receives pressurized high-pressure fuel from the fuel pressurization device and injects it into a combustion chamber.

14. Fuel tank; and It includes an engine that produces energy by receiving fuel from the above fuel tank, The above engine A fuel pressurization device according to any one of claims 1 to 12; and A vessel including an injector that receives pressurized high-pressure fuel from the fuel pressurization device and injects it into a combustion chamber.

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