Safety valve unit, engine, and ship

Abstract

According to one aspect of the present invention, provided is a safety valve unit comprising: a safety valve block having a fuel line interposed in a fuel pipe and an inert gas line connected to the fuel line; a plurality of valve modules inserted into valve seating portions of the safety valve block; a valve sensor for detecting whether the plurality of valve modules are opened or closed; and a control unit for receiving operation state information from the valve sensor and controlling opening and closing of the plurality of valve modules, wherein the valve modules comprise: a purge valve for opening and closing the fuel line; and an inert gas valve for controlling flow of inert gas in the inert gas line.

Description

Safety valve units, engines and ships

[0001] The present invention relates to a safety valve unit for an engine using low flashpoint fuel, an engine including the same, 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 purpose of the present invention is to provide a safety valve unit, an engine, and a ship capable of efficiently utilizing low flashpoint fuel.

[0009] A fuel line interposed in a fuel pipe; a purge valve for opening and closing the fuel line; an operating oil valve for selectively supplying operating oil supplied from an operating oil pump to the purge valve; and a control unit for controlling the operating oil valve, wherein the purge valve comprises: a fuel passage connected to the fuel line; a purge valve piston that moves linearly and selectively shields one end of the fuel passage; and an operating oil inlet connected to the operating oil pump at the other end of the purge valve piston, wherein the purge valve piston provides a safety valve unit for closing the fuel passage when pressurized operating oil is supplied from the operating oil pump.

[0010] The above purge valve may further include a valve spring that pressurizes the purge valve piston in the other direction.

[0011] The pressure of the operating fluid supplied to the operating fluid inlet may have a pressure higher than the fuel pressure on the fuel line.

[0012] The above safety valve unit includes a liquid detection sensor located on the fuel line at the rear end of the purge valve, and the control unit can close the purge valve when liquid is detected by the liquid detection sensor when fuel is injected into the fuel pipe with the purge valve open.

[0013] The above control unit can determine that there is a fuel leak abnormality when liquid is detected by the liquid detection sensor while the purge valve is closed.

[0014] The above liquid detection sensor may be located below the purge valve.

[0015] The above safety valve unit includes an inert gas supply module located at a rear end of the fuel line relative to the purge valve, and the inert gas supply module can supply an inert gas to the fuel line when the purge valve is closed.

[0016] The above inert gas supply module may include a plurality of inert gas valves arranged vertically.

[0017] The above inert gas supply module includes: an inert gas line connected to the rear end of the purge valve; a pair of inert gas block valves located in the inert gas line; an inert gas bleed valve for opening and closing an inert gas bleed line connected between the inert gas block valves; and a control air valve for selectively supplying air for opening and closing the pair of inert gas block valves and the inert gas bleed valve, wherein when the control air valve is opened, the pair of inert gas block valves are opened and the inert gas bleed valve is closed, and when the control air valve is closed, the pair of inert gas block valves are closed and the inert gas bleed valve can be opened.

[0018] An auxiliary line is included that is connected to the outer space of the fuel pipe having a double-tube structure, and the inert gas bleed line can be connected to the auxiliary line.

[0019] The above inert gas supply module may further include a check valve positioned between the pair of inert gas block valves and the fuel line.

[0020] The above safety valve unit includes a bypass line connected to the fuel line and bypassing the purge valve; and a safety valve located on the bypass line, wherein the safety valve can be opened when the pressure at the front end of the purge valve is higher than a threshold pressure.

[0021] The above safety valve unit includes a safety valve block having the fuel line formed therein, and the safety valve block may include a purge valve mounting portion into which the purge valve is inserted.

[0022] According to one aspect of the present invention, a safety valve unit is provided, comprising: a safety valve block including a fuel line interposed in a fuel pipe and an inert gas line connected to the fuel line; a plurality of valve modules inserted into a valve seating portion of the safety valve block; a valve sensor detecting whether the plurality of valve modules are open or closed; and a control unit receiving operating status information from the valve sensor and controlling the opening or closing of the plurality of valve modules, wherein the valve module includes a purge valve opening or closing the fuel line; and an inert gas valve controlling the flow of an inert gas on the inert gas line.

[0023] The above control unit can open the purge valve after detecting a closed state of the inert gas valve from the valve sensor.

[0024] The above control unit can open the inert gas valve after detecting a closed state of the purge valve from the valve sensor.

[0025] The above plurality of valve modules include a valve housing having a fluid passage formed on one side thereof to be connected to the fuel line or the inert gas line; and a valve piston inserted into the valve housing to open and close the fluid passage, and the valve sensor can detect the position of the valve piston in a non-contact manner.

[0026] One side of the valve piston is located within the safety valve block and the other side is located outside the safety valve block, and the valve sensor can detect the position of the other side of the valve piston to determine whether the piston is open or closed.

[0027] It may include a sensor housing that covers the other side of the valve piston and accommodates the valve sensor.

[0028] The safety valve block may include a cantilever protruding from the outside adjacent to the valve piston and on which the valve sensor is located.

[0029] The above valve sensor may include a valve magnet attached to the valve piston; and a magnetic sensor that determines whether the valve piston is open or closed based on a change in the strength of the magnetic force of the valve magnet.

[0030] The above valve sensor may include an optical sensor that detects the position of the valve piston by receiving light transmitted toward the other end of the valve piston.

[0031] The above valve sensor may include a plurality of links connecting the plurality of valve modules; and a displacement sensor detecting a change in position of the links.

[0032] The above inert gas valves can be arranged in a plurality of vertical directions.

[0033] The above safety valve unit includes a pressure sensor that measures the pressure of the fuel line, and the control unit can open the inert gas valve to inject nitrogen when the inert gas pressure detected by the pressure sensor is lower than the reference pressure.

[0034] According to one aspect of the present invention, there is provided a fuel line interposed in a fuel pipe; a purge valve for opening and closing the fuel line; a first control air line for supplying control air for controlling opening and closing of the purge valve; a first purge control valve for opening and closing the first control air line; and a control unit for controlling the first purge control valve to drive the purge valve, wherein the purge valve comprises a fuel passage connected to the fuel line and including an outlet passage extending in a first direction and an inlet passage extending in a second direction perpendicular to the first direction; a purge valve piston that moves linearly in the first direction and has one end selectively shielding between the inlet passage and the outlet passage; and a control air inlet to which control air is supplied to the other end of the purge valve piston, wherein when the control air is supplied, the purge valve piston moves in the first direction and shields between the inlet passage and the outlet passage.

[0035] The pressure of the control air supplied to the purge valve may be lower than the pressure of the fuel supplied to the fuel line.

[0036] The above purge valve piston may have a larger area at the other end than the area at the first end.

[0037] The above purge valve piston may include a first tapered section that overlaps at least a portion of the inlet passage and whose cross-sectional area increases from one end to the other.

[0038] The above purge valve piston includes a second tapered section that overlaps at least partly with the inlet passage and has a cross-sectional area that decreases from one end to the other, and the second tapered section can be located in the other end direction relative to the first tapered section.

[0039] The safety valve unit may include an inert gas supply module located at a rear end of the fuel line relative to the purge valve, and the inert gas supply module may include: an inert gas line connected to a rear end of the purge valve; an inert gas block valve selectively opening and closing the inert gas line; a second control air line supplying control air that controls opening and closing of the inert gas block valve; and a control air valve opening and closing the second control air line.

[0040] The first control air line and the second control air line can be connected at the front end of the first purge control valve and the control air valve.

[0041] The above inert gas supply module includes a pair of inert gas block valves; an inert gas bleed line connected to the inert gas line between the pair of inert gas block valves; and an inert gas bleed valve for opening and closing the inert gas bleed line, wherein when the control air valve is opened, the pair of inert gas block valves are opened and the inert gas bleed valve is closed, and when the control air valve is blocked, the pair of inert gas block valves are closed and the inert gas bleed valve is opened.

[0042] An auxiliary line is included that is connected to the outer space of the fuel pipe having a double-tube structure, and the inert gas bleed line can be connected to the auxiliary line.

[0043] A relief line connected to the fuel line and bypassing the purge valve; a relief valve positioned on the relief line; a third control air line supplying control air for controlling opening and closing of the purge valve; and a second purge control valve for opening and closing the third control air line, wherein the control unit can first close the second purge control valve before closing the first purge control valve so that the relief valve is opened before opening the purge valve.

[0044] The above relief valve may have a smaller size than the above purge valve.

[0045] A bypass line connected to the fuel line and bypassing the purge valve; and a safety valve located on the bypass line, wherein the safety valve can be opened when the pressure in front of the purge valve is higher than a threshold pressure. According to another aspect of the present invention, an engine is provided, comprising: an injector for injecting fuel into a combustion chamber; an injector pipe for supplying fuel to the injector; a fuel pipe branched from the injector pipe; and the safety valve unit located on the fuel pipe, wherein the operating fluid pump supplies pressurized operating fluid to the injector.

[0046] The fuel may comprise either methanol or ammonia.

[0047] According to another aspect of the present invention, a ship is provided, comprising: a fuel tank; and an engine that receives fuel from the fuel tank and produces energy, the engine including: an injector that injects fuel into a combustion chamber; an injector pipe that supplies fuel to the injector; a fuel pipe branched from the injector pipe; and the safety valve unit positioned on the fuel pipe, wherein the operating oil pump supplies pressurized operating oil to the injector.

[0048] The safety valve unit of an engine according to at least one embodiment of the present invention can minimize the risk of damage to the piping by arranging a complex piping structure connected to a purge valve and an inert gas valve inside a safety valve block.

[0049] In addition, the engine according to at least one embodiment of the present invention has the effect of configuring the purge valve and the inert gas supply module as one part, thereby facilitating the manufacture of the engine and simplifying the configuration.

[0050] Additionally, the engine according to at least one embodiment of the present invention can reduce the size of the safety valve module by reducing the size of the purge valve and miniaturizing the valve sensor.

[0051] Additionally, the safety valve unit of the engine according to at least one embodiment of the present invention can drive the purge valve using low-pressure control air.

[0052] In addition, the engine according to at least one embodiment of the present invention can minimize errors due to vibration and mechanical deformation by implementing the valve sensor in a non-contact manner.

[0053] 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.

[0054] FIG. 1 is a diagram illustrating an engine system according to a first embodiment of the present invention.

[0055] FIG. 2 is a diagram illustrating an engine system according to a second embodiment of the present invention.

[0056] FIG. 3 is a diagram illustrating an engine system according to a third embodiment of the present invention.

[0057] FIG. 4 is a conceptual diagram illustrating one embodiment of a safety valve unit of an engine system according to the second embodiment of the present invention and the embodiment of FIG. 3.

[0058] Fig. 5 is a cross-sectional view illustrating an embodiment of a purge valve of a safety valve unit of the present invention. Fig. 6 is a cross-sectional view illustrating a second embodiment of a valve sensor of a safety valve unit of the present invention.

[0059] Figure 7 is a diagram illustrating another embodiment of the safety valve unit of the present invention.

[0060] Fig. 8 is a cross-sectional view showing an embodiment of a purge valve of the safety valve unit of the present invention.

[0061] Figures 9a to 9c are drawings showing a purge valve that uses high-pressure oil as control air and a purge valve that uses relatively low-pressure gas as control air.

[0062] Fig. 10 is a diagram illustrating another embodiment of the safety valve unit of the present invention.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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).

[0075] The present embodiment includes a methanol engine (10) that uses methanol (CH3OH) as fuel.

[0076] 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).

[0077] 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.

[0078] 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.

[0079] 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).

[0080] 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).

[0081] 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.

[0082] 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.

[0083] 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).

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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).

[0089] 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.

[0090] 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).

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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).

[0095] 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).

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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).

[0101] 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.

[0102] 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.

[0103] 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).

[0104] 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.

[0105] 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).

[0106] 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.

[0107] 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).

[0108] 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).

[0109] 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.

[0110] 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.

[0111] 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).

[0112] 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.

[0113] 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).

[0114] 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).

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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).

[0123] 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).

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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).

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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).

[0133] FIG. 3 is a diagram illustrating an ammonia engine system (3) according to a third embodiment of the present invention.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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).

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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).

[0146] 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).

[0147] 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.

[0148] 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.

[0149] 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).

[0150] 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.

[0151] 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).

[0152] 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).

[0153] 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).

[0154] 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.

[0155] 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).

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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).

[0160] 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).

[0161] 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).

[0162] 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.

[0163] 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).

[0164] FIG. 4 is a diagram illustrating a safety valve unit (140) according to the second embodiment of the present invention and the embodiment of FIG. 3.

[0165] The safety valve unit (140) may include a purge valve (141) and a rear inert gas supply module (146). The fuel pipe inside the engine (10) branches into an injector fuel pipe (L4) supplied to the injector (110) and a fuel discharge pipe (L5) for discharging fuel from the engine, and the safety valve unit (140) may be located on the fuel discharge pipe (L5).

[0166] The safety valve unit (140) may include a purge valve (141) and a rear inert gas supply module (146). The purge valve (141) selectively opens and closes the fuel discharge pipe (L5), and is closed so that fuel is supplied to the injector fuel pipe (L4) when the engine (10) is driven, and is opened when the engine (10) is stopped so that the fuel inside the engine (10) can be discharged (purged) to the fuel recovery pipe (L6).

[0167] The safety valve unit (140) is configured as a single module with a purge valve (141) and an inert gas valve (146) required at the rear end of the engine's fuel pipe (L5), and a valve mounting portion is formed inside the safety valve block (149) and a plurality of valve modules (141, 146) can be mounted.

[0168] The purge valve (141) is opened before the operation of the engine (10) (here, operation means that fuel is injected and combusted through the injector (110)) so that the fluid in the fuel discharge pipe (L5) is discharged and fuel can be filled up to the purge valve (141).

[0169] In the case of the ammonia engine system (3), the fuel discharge pipe (L5) is filled with an inert gas in advance, so the inert gas passes through the purge valve (141) and moves to the fuel recovery pipe (L6).

[0170] When the fuel inside the fuel discharge pipe (L5) is filled up to the purge valve (141), the purge valve (141) can be closed to maintain the fuel pressure inside the engine (10), and high-pressure fuel can be supplied to the injector (110).

[0171] If the fuel pressure inside the engine (10) becomes excessively high while the engine (10) is running, there may be a risk of accident. When the purge valve (141) is opened, the fuel pressure inside the engine (10) decreases, so the engine (10) must be stopped.

[0172] It may further include a bypass line (1435) that bypasses the purge valve (141) to lower the pressure inside the engine (10) without opening the purge valve (141), and a safety valve (143) located on the bypass line (1435).

[0173] The safety valve (143) can be opened only when the pressure inside the engine (10) (pressure of the fuel discharge pipe (L5)) is above a predetermined pressure, and the safety valve (143) can be controlled through a pressure sensor, or a backflow prevention valve that opens when the pressure is above a predetermined pressure and blocks flow in the reverse direction can be used.

[0174] The purge valve (141) can be opened and closed by receiving operating fluid, and the operating fluid can be supplied from an operating fluid pump (130) that supplies operating fluid to the injector (110). An operating fluid valve (SV145) can be further provided between the purge valve (141) and the operating fluid pump (130) so that the injector (110) and the purge valve (141) can be operated independently.

[0175] The control unit can open the operating oil valve (SV145) to supply operating oil to the purge valve (141), and the purge valve (141) can be closed to block the fuel pipes (L5, L6). In addition, the control unit can close the operating oil valve (SV145) to stop the supply of operating oil to the purge valve (141), and the purge valve (141) can be opened to open the fuel pipes (L5, L6).

[0176] In order to recover the fuel that has flowed to the rear end of the purge valve (141) during the fuel injection stage, the rear end inert gas supply module (146) can supply inert gas to the rear end of the purge valve (141) to discharge the fuel through the fuel recovery pipe (L6).

[0177] The rear inert gas supply module (146) supplies inert gas to the rear end of the purge valve (141) and discharges fuel at the rear end of the purge valve (141) after the purge valve (141) is closed. Since the rear inert gas supply module (146) is directly connected to the rear end of the purge valve (141), the purge valve (141) and the rear inert gas supply module (146) can form a safety valve unit (140) that controls the flow of fuel within the engine (10).

[0178] The rear inert gas supply module (146) may include an inert gas line (1462) connected to a fuel discharge pipe (L5) and a plurality of inert gas valves (1465) to prevent fuel from flowing back into the inert gas line (1462) and to ensure stable inert gas supply.

[0179] The inert gas valve (1465) may include a pair of inert gas block valves (1465a, 1465b) positioned in the inert gas line (1462) and may include an inert gas bleed line (1463) connected between the pair of inert gas block valves (1465a, 1465b).

[0180] It includes an inert gas bleed valve (1465c) that opens and closes an inert gas bleed line (1463), and the opening and closing of a pair of inert gas block valves (1465a, 1465b) and the inert gas bleed valve (1465c) can be controlled by control air. The control air can operate the inert gas valve (1465) by pressurizing the piston of the inert gas valve (1465) with a predetermined pressure.

[0181] A control air valve (SV146) may be included to control the supply of control air to a pair of inert gas block valves (1465a, 1465b) and an inert gas bleed valve (1465c). When the control air valve (SV146) is opened, the control air is supplied, and when the pair of inert gas block valves (1465a, 1465b) are opened and the inert gas bleed valve (1465c) is closed, the inert gas is supplied to the fuel discharge pipe (L5).

[0182] When the control air valve (SV146) is blocked, a pair of inert gas block valves (1465a, 1465b) are closed, the supply of inert gas is stopped, and when the inert gas bleed valve (1465c) is opened, the inert gas between the pair of inert gas block valves (1465a, 1465b) can be discharged.

[0183] The fuel discharge pipe (L5) may have a double-pipe structure. That is, it includes an outer space located around the main pipe, so that even if a leak occurs in the main pipe, it can be discharged through the outer space. The outer space is periodically ventilated by injecting air, and an inert gas bleed line (1463) may be connected to the outer space of the fuel discharge pipe (L5).

[0184] The inert gas line (1462) may further include a check valve (1464) positioned between the inert gas block valves (1465a, 1465b) and the fuel discharge pipe (L5) to prevent fuel from flowing backward. The safety valve unit (140) may include a purge valve (141) and a rear inert gas supply module (146). The safety valve unit (140) may include a safety valve block (149) that accommodates the purge valve (141) and the rear inert gas supply module (146).

[0185] The safety valve block (149) can accommodate a fuel line (142) through which fuel passes, an inert gas line (1462) through which an inert gas is supplied, and a control air line (1477) through which control air is supplied.

[0186] Although a plurality of pipes may be arranged inside a shell including an internal space, the safety valve block (149) of the present invention may be implemented in the form of a solid block including holes formed along the lines (142, 1462, 1477) through which each fluid moves. The safety valve block (149) has the advantage of not requiring the arrangement of pipes and not generating leaks because there are no connecting parts inside.

[0187] The safety valve block (149) overlaps with the fuel line or the inert gas line and may include a valve mounting portion in which the purge valve (141) or the inert gas valve (1465) is mounted. The flow of the fuel line or the inert gas line can be controlled by inserting the purge valve (141) or the inert gas valve (1465) into the valve mounting portion. One end of the purge valve (141) or the inert gas valve (1465) may be positioned within the safety valve block (149) and the other end may be exposed to the outside of the safety valve block (149).

[0188] A plurality of valves connected to the fluid line, a pressure sensor (PT14-1, PT14-2), a liquid detection sensor (LS1), a solenoid valve (143), etc. can be installed in the safety valve block (149).

[0189] Since the purge valve (141) and the rear inert gas supply module (146) are connected to the rear end of the fuel discharge pipe (L5), the safety valve unit (140) may include a fuel inlet (1421) connected to the fuel discharge pipe (L5) and a fuel discharge port (1422) connected to the fuel recovery pipe (L6).

[0190] Since the fuel discharge pipe (L5) has a double-pipe structure including an outer space around the periphery, the fuel inlet (1421) and the fuel discharge port (1422) connected to the fuel discharge pipe (L5) may also further include an auxiliary line (1423) connected to the outer space.

[0191] The purge valve (141) is located in the fuel line (142) between the fuel inlet (1421) and the fuel outlet (1422), and opens and closes the fuel line (142) depending on ON / OFF, and can control the flow from the fuel discharge pipe (L5) inside the engine to the fuel recovery pipe (L6) at the rear of the engine.

[0192] Although not clearly shown in the diagram, the purge valve (141) may be located above the fuel inlet (1421) and fuel outlet (1422).

[0193] The rear inert gas supply module (146) is composed of a plurality of inert gas valves (1465), and each inert gas valve (1465) is connected to an inert gas line (1462) and a control air line (1477), so it is preferable to arrange them in series. Three inert gas valves (1465) can be arranged vertically side by side, and the purge valve and fuel line can be arranged adjacent to them.

[0194] As seen in Fig. 2, the safety valve unit (140) of the second embodiment has a different operating fluid pressure from the safety valve unit (140) of the first embodiment. The operating fluid of the first embodiment is supplied from a hydraulic pump (151), and the operating fluid of the second embodiment is supplied from a working fluid pump (130) that supplies working fluid to the injector (110). Since the working fluid of the second embodiment has a higher pressure, the purge valve (141) of the second embodiment can be implemented with a smaller size.

[0195] Fig. 5 is a cross-sectional view illustrating a purge valve (141) of a safety valve unit (140) of an engine system (1) of the present invention. (a) is a cross-sectional view of a purge valve (141) according to the first embodiment of Fig. 1, and (b) is a cross-sectional view of a purge valve (141) according to the second and third embodiments of Figs. 2 and 3.

[0196] The purge valve (141) includes a piston housing (1417) in which a fuel passage (1411) is formed at one end and a valve piston (1416) that moves linearly inside the piston housing (1417) according to the supply of operating fluid. When the valve piston (1416) moves to one side (left side in the drawing), the fuel passage (1411) is blocked so that fuel cannot pass through.

[0197] The purge valve (141) includes a valve spring (1415) that applies force in the direction of opening the piston (1416). The purge valve (141) may include an operating fluid inlet (1414) into which operating fluid is injected on the right side of the valve piston (1416) in the drawing. When operating fluid is injected into the operating fluid inlet (1414), the valve piston (1416) moves to the left and the purge valve (141) closes.

[0198] The safety valve system according to the first embodiment receives operating oil for opening and closing the purge valve (141) from a hydraulic pump (151). The pressure of the oil (Hyd. Oil) supplied from the hydraulic pump (151) is low, at the level of 300-350 bar, so the cross-sectional area of ​​the valve piston (1416) must be large in order to provide sufficient force to shield high-pressure (400-600 bar) fuel.

[0199] Since the injector (110) and the fuel pressurization device (120) must be sealed in advance before fuel is supplied, the hydraulic pump (151) supplies low-pressure hydraulic oil before fuel is filled into the engine. The purge valve (141) must use a valve spring (1415) having a large elasticity so that it does not close when low-pressure hydraulic oil is supplied, but closes when high-pressure hydraulic oil is supplied. In addition, as described above, since the cross-sectional area of ​​the valve piston (1416) is large, a spring having a large elasticity can be applied as the elasticity of the valve spring (1415).

[0200] Meanwhile, the safety valve system according to the second embodiment receives the working oil supplied to the injector (110) as the working oil for opening and closing the purge valve (141). The working oil supplied to the injector (110) may be working oil (C&S oil) pressurized to 450-650 bar from the working oil pump (130). Since the pressure of the working oil is greater than that of the first embodiment, the area of ​​the valve piston (1416) can also be reduced (d2 <d1). 밸브 피스톤(1416)의 크기가 작아질 수 있다.

[0201] However, even before the engine is driven, the working fluid supplied from the working fluid pump (130) to fill the fuel pipe inside the engine with fuel has a predetermined pressure, so that the purge valve (141) can be closed. Therefore, a working fluid valve (SV145) may be further provided between the purge valve (141) and the working fluid pump (130) so that the injector (110) and the purge valve (141) can be driven independently. The working fluid valve (SV 145) controls the purge valve (141) by controlling the supply of working fluid, so it can also be called a purge control valve.

[0202] The operating oil valve (SV 145) can use a solenoid valve that can be controlled by an electrical signal. When the operating oil valve (SV145) opens, operating oil is supplied to the purge valve (141), and the purge valve (141) closes. When the operating oil valve (SV145) closes, the supply of operating oil to the purge valve (141) is stopped, and the purge valve (141) opens.

[0203] Since the operating oil valve (SV145) controls the operating oil supplied to the purge valve (141), the operating oil is not supplied when the purge valve (141) is open. Therefore, the elasticity of the valve spring (1415) that presses the valve piston (1416) in the other direction can be a spring having a small elasticity that can support the weight of the valve piston (1416).

[0204] For example, the valve spring (1415) of the first embodiment requires a spring with large elasticity, but the valve spring (1415) of the second embodiment can be sufficiently equipped with a spring with smaller elasticity (e.g., 1 / 20 to 1 / 30 times the size) than that of the first embodiment.

[0205] Since the valve spring (1415) has a larger size as its elasticity increases, the valve spring (1415) of the second embodiment may be smaller than the valve spring (1415) of the first embodiment.

[0206] According to the second embodiment, the size of the valve piston (1416) and the size of the valve spring (1415) can be reduced, so that the size of the purge valve (141) can be reduced by about 50%, and the size of the safety valve unit (140) can be reduced by about 30%, thereby reducing manufacturing costs. The safety valve unit (140) can include a purge valve (141) and a plurality of inert gas valves (1465). The purge valve (141) and the inert gas valves (1465) are connected to the fuel discharge pipe (L5), and must be opened and closed in conjunction with each other.

[0207] If the purge valve (141) is not closed properly, the inert gas valve (1465) may be opened, or if the purge valve (141) is opened while the inert gas valve (1465) is not closed, fuel may flow back along the inert gas line (1462).

[0208] Accordingly, the safety valve unit (140) may further include a valve sensor to monitor whether the purge valve (141) and the inert gas valve (1465) are operating normally. The valve sensor detects the movement of the valve piston and can recognize the opening and closing of the valve. The valve sensor according to the first embodiment can indirectly detect the movement of the valve piston through the installation of a link mechanism and a limit sensor.

[0209] The link mechanism includes a link structure connecting a plurality of valves, and the link moves together with the opening and closing of each valve, and can detect whether the valve (141, 1465) is opened or closed.

[0210] Fig. 6 is a cross-sectional view illustrating a valve sensor of a safety valve unit (140) of the present invention according to a second embodiment. The valve sensor of this embodiment may include a proximity sensor that detects the position of the piston in a non-contact manner.

[0211] Proximity sensors can be optical sensors that detect the piston's position using light of a specific wavelength, such as infrared or laser. Alternatively, they can be magnetic sensors that detect a magnet located on the piston.

[0212] Figure 6 (a) shows an inert gas valve sensor (1468) attached to an inert gas valve (1465), and Figure 6 (b) shows a purge valve sensor (1418) attached to a purge valve (141). Both the inert gas valve sensor (1468) and the purge valve sensor (1418) may be configured as a magnet and a sensor that detects the magnetic force of the magnet.

[0213] The magnets (1417, 1467) can be coupled to the pistons of the inert gas valve (1465) and the purge valve (141). One end of the piston of the inert gas valve (1465) opens and closes the inert gas line (1462) through which the inert gas flows, and one end of the purge valve piston (1416) opens and closes the fuel discharge pipe (L5) through which the fuel flows, so the magnets (1417, 1467) can be located at the other ends of the piston of the inert gas valve (1465) and the purge valve piston (1416).

[0214] The sensor can be placed adjacent to the magnet (1417, 1467) and can be placed adjacent to the valve piston (1416, 1466) because it detects the horizontal movement of the valve piston (1416, 1466).

[0215] The optical sensor can check the open / closed status of the inert gas valve or purge valve based on whether it overlaps with the optical sensor. Alternatively, the open / closed status of the inert gas valve or purge valve can be checked through the distance from the piston in the direction of movement of the piston. The inert gas valve (1465) can have the magnet (1467) and the sensor (1468) positioned inside the safety valve block (149) to minimize damage due to external force and the influence of vibration. Alternatively, the other side of the inert gas valve piston (1466) protruding from the safety valve block (149) and the magnet (1467) can be covered, and a sensor housing (1469) in which the inert gas valve sensor (1468) is mounted can be included.

[0216] Referring to (b) of Fig. 6, the other end of the purge valve piston (1416) and the purge valve magnet (1417) are exposed to the outside. The purge valve (141) can be positioned exposed to the outside to ensure manual operability and to visually confirm movement.

[0217] Since the purge valve piston (1416) protrudes from the safety valve block (149), a cantilever (1419) protruding from the safety valve block (149) may be included to place the purge valve sensor (1418).

[0218] By placing a purge valve sensor (1418) on a cantilever (1419), the magnetic force of the purge valve magnet (1417) located at the other end of the purge valve piston (1416) can be detected.

[0219] The proximity sensor of the second embodiment is smaller in volume than the sensor structure including the link mechanism of the first embodiment, and by omitting the externally exposed link mechanism, the risk of damage due to vibration or external force can be eliminated. Furthermore, since it detects the piston position in a non-contact manner, it has the advantage of preventing mechanical contact deformation.

[0220] The safety valve unit (140) of the present invention may further include various sensors and an electrically driven solenoid valve in addition to the purge valve (141) and the rear inert gas supply module (146).

[0221] For example, the safety valve unit (140) of the present invention may include pressure sensors (PT14-1, PT14-2) positioned before and after the purge valve (141) to detect the pressure within the fuel discharge pipe (L5). A liquid sensor (LS1) may be included adjacent to the fuel discharge port (1422) to detect the presence or absence of liquid fuel at the rear end of the purge valve (141).

[0222] Additionally, a solenoid valve may be mounted as an operating oil valve (SV145) for selectively supplying operating oil to the purge valve (141) and a control air valve (SV146) for selectively supplying control air to the inert gas valve (1465).

[0223] The fuel line (142) includes a fuel inlet (1421) and a fuel outlet (1422) connected to a fuel discharge pipe (L5), and a purge valve (141) may be interposed on the fuel line (142). Operating fluid is supplied to the purge valve (141) through an operating fluid line (1455). An operating fluid valve (SV145) responsible for opening and closing the operating fluid line (1455) may be positioned on the operating fluid line (1455).

[0224] The fuel line (142) is connected to the inert gas line (1462) and can receive inert gas from the rear inert gas supply module (146). The inert gas line (1462) has a plurality of inert gas valves (1465) interposed therebetween, and the inert gas valves (1465) can be opened and closed depending on whether control air is supplied to the inert gas valves (1465). The control air valve (SV146) is an electric valve such as a solenoid valve and can control the control air supplied to the inert gas valves (1465).

[0225] Figure 7 is a diagram illustrating another embodiment of the safety valve unit of the present invention.

[0226] The purge valve (141) of this embodiment can be operated by receiving control air as a working fluid that controls opening and closing. The purge valve (141) of the embodiment of Fig. 4 is controlled by using liquid-state control oil as a working fluid, but the purge valve (141) of this embodiment is operated by receiving control air in a gaseous state.

[0227] The control unit can drive the purge valve (141) by controlling the first purge control valve (SV145-1) that controls the supply of control air supplied to the purge valve (141).

[0228] The control air supplied to control the inert gas valve (1465a, 1465b, 1465c) can be supplied by pressurizing air in the atmosphere. At this time, the supplied control air can have a pressure of about 20 bar or less.

[0229] The safety valve unit (140) of the present embodiment can use the control air supplied to the inert gas valves (1465a, 1465b, 1465c) as the control air supplied to the purge valve (141). If the purge valve (141) and the inert gas valves (1465a, 1465b, 1465c), which control the flow of fuel and inert gas of the safety valve unit (140), are driven by the same control air, the piping connected to the safety valve unit (140) can be simplified.

[0230] The embodiment of Fig. 5 controls the purge valve (141) using high-pressure control oil at the level of 300-650 ar. By using high-pressure control oil, the flow of pressurized fuel (400-600 bar) can be controlled.

[0231] However, since the pressure of the control air driving the purge valve according to the embodiment of FIG. 7 has a lower pressure than that of the embodiment described above, it is difficult to open and close the flow of fuel with the purge valve of the type shown in FIG. 5.

[0232] Fig. 8 is a cross-sectional view illustrating an embodiment of a purge valve of a safety valve unit of the present invention. The purge valve (141) may include a cylindrical valve housing (1417) having a fuel passage (1411) formed at one end and a valve piston (1416) inserted into the other end of the valve housing (1417).

[0233] The fuel passage (1411) includes an inlet passage (1411a) through which fuel is introduced and an outlet passage (1411b) through which fuel is discharged, and the inlet passage (1411a) and the outlet passage (1411b) are arranged at right angles and in an L shape.

[0234] The valve piston (1416) is located between the inlet passage (1411a) and the outlet passage (1411b) and blocks fuel flowing into the inlet passage (1411a) from moving to the outlet passage (1411b).

[0235] In the purge valve of this embodiment, the directions of the fuel inlet passage (1411a) and the fuel discharge passage (1411b) may be arranged opposite to those of the embodiment described above.

[0236] The fuel inlet passage (1411a) can be arranged in a second direction (D2) perpendicular to the direction (D1) in which the valve piston (1416) of the purge valve (141) moves, thereby preventing the valve piston (1416) from being opened by the pressure of the fuel.

[0237] Figures 9a to 9c are drawings showing a purge valve (141) that uses high-pressure oil as control air and a purge valve (141) that uses relatively low-pressure gas as control air.

[0238] The purge valve (141) of Fig. 9a illustrates one end of a purge valve according to the embodiment of Fig. 5 (b). In the embodiment of Fig. 9 (a), an inlet passage (1411a) may be positioned parallel to a first direction in which a valve piston (1416) moves, and an outlet passage (1411b) may be positioned in a second direction (D2) perpendicular to the first direction (D1).

[0239] The magnitude of the force applied in the direction of movement of the valve piston (1416) can be composed of the pressure (P) and the cross-sectional area (D) of the valve piston (1416) to which the pressure is applied. The pressure of the high-pressure oil as the control air injected into the other end (1416b) of the valve piston (1416) has a lower pressure than the pressure (Pf) of the pressurized fuel used in the engine (10).

[0240] The valve piston (1416) can be configured so that the diameter of one end (1416a) in the first direction is small and the other end (1416b) is large so that the area pressurized by the high-pressure oil is larger than the cross-sectional area of ​​the inlet passage (1411a) (ⓐ<ⓑ).

[0241] When the purge valve (141) of the structure of FIG. 9a is controlled by low-pressure gas as control air, the area of ​​the other end (1416b) of the valve piston (1416) increases to support the fuel flowing into the purge valve (141) in the first direction (D1). In order to prevent the structure of the safety valve unit (140) from becoming large, the inflow passage (1411a) may be arranged in the second direction as shown in FIG. 9 (b) to minimize the force applied in the direction in which the valve piston (1416) opens.

[0242] The valve piston (1416) of FIG. 9b may include a first tapered section (1416c) that has a larger area at one end (1416a) than at the other end (1416b) and widens from one end to the other end while overlapping with the inlet passage (1411a). The first tapered section (1416c) has an inclined side surface. The area (ⓒ) through which the force of the fuel is transmitted to the valve piston (1416) in the first direction (D1) through the inclined side surface of the valve piston (1416) is smaller than that of the embodiment of FIG. 9 (a) (ⓒ<ⓐ).

[0243] In the embodiment of Fig. 9b, the magnitude of the force (ⓒ x Pf) that the fuel flowing in the second direction (D2) presses the valve piston (1416) in the first direction is smaller than the magnitude of the force (ⓐxPf) that the fuel flowing in the first direction presses the valve piston (1416) in the first direction in the embodiment of Fig. 9a.

[0244] The purge valve (141) of Fig. 9b can withstand the force exerted by high-pressure fuel to pressurize the valve piston (1416) in the first direction using low-pressure gas. This reduces the cost of raising the oil to high pressure, and the use of low-pressure control air improves the durability of the purge valve.

[0245] FIG. 9c is an embodiment including a second tapered section (1416d) whose diameter is narrowed in the opposite direction from the embodiment of FIG. 9b.

[0246] The slope of the first taper section (1416c) with a smaller cross-section in one direction can convert the pressure of the fuel flowing into the inlet passage (1411a) into a force that pressurizes the valve piston in the other direction.

[0247] Conversely, if a second tapered section (1416d) having a smaller cross-section in the opposite direction is added, the slope of the side surface of the second tapered section (1416d) faces the opposite direction to that of the first tapered section (1416c). The second tapered section (1416d) is formed at a position overlapping the inlet passage (1411a), so that the fuel pressure applied to the inclined surface of the second tapered section (1416d) can be converted into a force that pushes the valve piston in one direction.

[0248] Accordingly, the force that pressurizes the valve piston (1416) in the other direction by the pressure of the fuel flowing into the inlet passage (1411a) through the second taper section (1416d) is reduced, and the pressure of the control air supplied to close the valve piston (1416) can be lowered.

[0249] Fig. 10 is a drawing illustrating another embodiment of the safety valve unit (140) of the present invention. When the purge valve (141) is opened, high-pressure fuel comes into contact with one end (1416a) of the valve piston (1416), flows from the inlet passage (1411a) to the outlet passage (1411b), and the one end (1416a) of the valve piston (1416) may be worn by the pressure of the fuel.

[0250] It may include a relief line (1445) that bypasses the purge valve (141) to lower the pressure of the fuel passing through the purge valve (141) and a relief valve (144) that opens and closes the relief line (1445).

[0251] The relief valve (144) is smaller in size than the purge valve (141) and can be opened and closed by control air like the purge valve (141). A second purge control valve (SV145-2) that controls the relief valve (144) can be located in a second control air line (1478) branched from a first control air line (1476) that supplies control air to the purge valve (141).

[0252] The relief valve (144) can be used to lower the initial pressure when the purge valve (141) is opened. When the engine (10) is stopped from running, the relief valve (144) is first opened to lower the pressure of the fuel inside the engine through the relief line (1445), and then the purge valve (141) is opened to reduce wear on the valve piston (1416) of the purge valve (141). Even if the relief valve (144) is worn, it can be replaced at a lower cost than the purge valve (141).

[0253] As described above, the safety valve unit of the engine according to at least one embodiment of the present invention can minimize the risk of damage to the piping by arranging a complex piping structure connected to the purge valve and the inert gas valve inside the safety valve block (149).

[0254] In addition, the engine according to at least one embodiment of the present invention has the effect of configuring the purge valve (141) and the rear inert gas supply module (146) as one part, thereby facilitating the manufacture of the engine and simplifying the configuration.

[0255] In addition, the engine according to at least one embodiment of the present invention can reduce the size of the safety valve module by reducing the size of the purge valve (141) and miniaturizing the valve sensor.

[0256] In addition, the engine according to at least one embodiment of the present invention can minimize errors due to vibration and mechanical deformation by implementing a valve sensor using magnetism.

[0257] 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.

[0258] 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.

[0259] The present invention is applicable to engines and ships in various fields, and thus its industrial applicability is recognized.

Claims

1. A safety valve block including a fuel line interposed in a fuel pipe and a safety valve block formed with an inert gas line connected to the fuel line; A plurality of valve modules inserted into the valve mounting portion of the above safety valve block; A valve sensor that detects whether the plurality of valve modules are open or closed; and A control unit that receives operating status information from the valve sensor and controls the opening and closing of the plurality of valve modules, The above valve module, A purge valve that opens and closes the above fuel line; A safety valve unit including an inert gas valve for controlling the flow of inert gas on the above inert gas line.

2. In paragraph 1, A safety valve unit characterized in that the control unit opens the purge valve after detecting a closed state of the inert gas valve from the valve sensor.

3. In paragraph 1, The above control unit A safety valve unit characterized in that the inert gas valve is opened after the valve sensor detects the closed state of the purge valve.

4. In paragraph 1, The above multiple valve modules A valve housing having a fluid passage formed on one side to connect to the fuel line or the inert gas line; and It includes a valve piston inserted into the valve housing to open and close the fluid passage, A safety valve unit characterized in that the valve sensor detects the position of the valve piston in a non-contact manner.

5. In paragraph 4, One side of the above valve piston is located within the safety valve block and the other side is located outside the safety valve block, A safety valve unit characterized in that the valve sensor detects the position of the other side of the valve piston to determine whether the piston is opened or closed.

6. In paragraph 5, A safety valve unit characterized by including a sensor housing that covers the other side of the valve piston and accommodates the valve sensor.

7. In paragraph 4, A safety valve unit characterized by including a cantilever protruding adjacent to the valve piston from the outside of the safety valve block and on which the valve sensor is located.

8. In paragraph 4, The above valve sensor a valve magnet attached to the above valve piston; and A safety valve unit characterized by including a magnetic sensor that determines whether the valve piston is open or closed based on a change in the strength of the magnetic force of the valve magnet.

9. In paragraph 4, A safety valve unit characterized in that the valve sensor includes an optical sensor that detects the position of the valve piston by receiving light transmitted toward the other end of the valve piston.

10. In paragraph 1, The above valve sensor A plurality of links connecting the plurality of valve modules; A safety valve unit characterized by including a displacement sensor that detects a change in position of the above link.

11. In paragraph 1, A safety valve unit characterized in that a plurality of the above inert gas valves are arranged vertically.

12. In paragraph 1, The above safety valve unit, Includes a pressure sensor that measures the pressure of the fuel line, A safety valve unit characterized in that the control unit opens the inert gas valve to inject nitrogen when the inert gas pressure detected by the pressure sensor is lower than the reference pressure.

13. Injector that injects fuel into the combustion chamber; An injector pipe supplying fuel to the above injector; A fuel pipe branched from the above injector pipe; and An engine system comprising a safety valve unit according to any one of claims 1 to 12 positioned on the fuel pipe.

14. Fuel tank; and It includes an engine that produces energy by receiving fuel from the above fuel tank, The above engine An injector that sprays fuel into the combustion chamber; An injector pipe supplying fuel to the above injector; A fuel pipe branched from the above injector pipe; and A vessel comprising a safety valve unit according to any one of claims 1 to 12 located on the fuel pipe.

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