Fuel supply system of marine ammonia fuel engine and preheating control method

Abstract

The invention relates to the technical field of marine engines, and discloses a fuel supply system of a marine ammonia fuel engine and a preheating control method.The fuel supply system of the marine ammonia fuel engine comprises a storage unit, a filter, a supply heat exchanger, an electric auxiliary heat exchanger, a cylinder sleeve water heat exchanger, a central water heat exchanger and a three-way valve; the input end of the first feeding side is connected with the storage unit, the output end of the first feeding side is connected with the filter, the output end of the electric auxiliary heat exchanger is connected with the input end of the first heat exchange side, the output end of the cylinder sleeve water heat exchanger is connected with the input end of the first heat exchange side, and the second feeding side is connected with a seawater source. The input end of the second heat exchange side is connected with the output end of the cylinder sleeve water heat exchanger, an A1 connector of the three-way valve communicates with one of an A2 connector and an A3 connector, ammonia fuel can be effectively heated before and after the engine is started, and additional energy consumption does not need to be increased.

Description

Technical Field

[0001] This invention relates to the field of marine engine technology, and in particular to a fuel supply system and preheating control method for marine ammonia fuel engines. Background Technology

[0002] Since ammonia contains no carbon or sulfur, it does not pose any carbon or sulfur emission problems and can be used as a low-carbon, clean fuel. Its combustion products are only nitrogen and water. Furthermore, it has the advantages of low emissions and can be stored, making it an important fuel potential for ship engines.

[0003] Because ammonia has a low boiling point and is easily vaporized, and ammonia-fueled engines require high-pressure liquid ammonia feed and stable feed parameters, the ammonia fuel supply system needs flexible and adjustable temperature and pressure control methods to prevent gas generation within the supply system. In existing marine engine ammonia fuel supply systems, sensors and control systems monitor the flow rate, pressure, and temperature of ammonia fuel in the supply pipeline, adjusting the system's flow rate, pressure, and heating devices accordingly. However, during the ammonia fuel preheating stage, before and after engine start-up, effective heating of the ammonia fuel is not possible, thus affecting the operational reliability of the marine engine.

[0004] Therefore, there is an urgent need for a fuel supply system and preheating control method for marine ammonia fuel engines to solve the above problems. Summary of the Invention

[0005] According to one aspect of the present invention, the fuel supply system for a marine ammonia fuel engine provided by the present invention can effectively heat the ammonia fuel before and after engine start-up without increasing additional energy consumption.

[0006] To address the aforementioned problems in the existing technology, the present invention adopts the following technical solution:

[0007] The fuel supply system for marine ammonia-fueled engines includes:

[0008] Storage unit;

[0009] Filter;

[0010] A supply heat exchanger having a first feed side and a first heat exchange side, wherein the input end of the first feed side is connected to the storage unit and the output end of the first feed side is connected to the filter;

[0011] An electric auxiliary heat exchanger, wherein the output end of the electric auxiliary heat exchanger is connected to the input end of the first heat exchange side;

[0012] A cylinder liner water heat exchanger, wherein the output end of the cylinder liner water heat exchanger is connected to the input end of the first heat exchange side;

[0013] A central water heat exchanger, the central water heat exchanger having a second feed side and a second heat exchange side, the second feed side being connected to a seawater source, and the input end of the second heat exchange side being connected to the output end of the cylinder liner water heat exchanger;

[0014] The three-way valve has an A1 port, an A2 port, and an A3 port. The A1 port is selectively connected to either the A2 port or the A3 port. The A1 port is connected to the output end of the first heat exchange side and the output end of the second heat exchange side. The A2 port is connected to the input end of the electric auxiliary heat exchanger. The A3 port is connected to the input end of the cylinder liner water heat exchanger.

[0015] Preferably, the fuel supply system of the marine ammonia fuel engine further includes a supply pump and an ejector, the input end of the supply pump is connected to the storage unit, the input end of the ejector is connected to the output end of the supply pump and the output end of the filter, and the output end of the ejector is connected to the input end of the first feed side.

[0016] Preferably, the fuel supply system of the marine ammonia fuel engine further includes an expansion tank, the input end of which is connected to an external fresh water source, and the output end of which is connected to the central water heat exchanger, the supply heat exchanger, and the cylinder liner water heat exchanger.

[0017] Preferably, the fuel supply system of the marine ammonia fuel engine further includes a first flow valve and a liquid level sensor electrically connected to the first flow valve. The input end of the first flow valve is connected to an external fresh water source, and the output end of the first flow valve is connected to the expansion tank. The liquid level sensor is installed in the expansion tank and is used to detect the liquid level in the expansion tank to change the valve opening of the first flow valve.

[0018] Preferably, the fuel supply system of the marine ammonia fuel engine further includes a gas leak detector, which is installed in the expansion tank and used to detect whether there is ammonia fuel leakage in the expansion tank.

[0019] Preferably, the fuel supply system of the marine ammonia fuel engine further includes a thermostatic control valve and a water pump. The input end of the water pump is connected to a seawater source, the output end of the water pump is connected to the second feed side, the input end of the thermostatic control valve is connected to the output end of the second heat exchange side, and the output end of the thermostatic control valve is connected to the A1 interface.

[0020] Preferably, the fuel supply system of the marine ammonia fuel engine further includes a thermometer, which is installed on the heat exchange side of the supply heat exchanger and the central water heat exchanger and is used to detect the temperature of the heat exchange medium in real time.

[0021] Preferably, the fuel supply system of the marine ammonia fuel engine further includes a second flow valve, and there are multiple second flow valves, which are respectively disposed at the input and output ends of the first feed side, the first heat exchange side, the second feed side, and the second heat exchange side.

[0022] According to another aspect of the present invention, a preheating control method for a fuel supply system of a marine ammonia fuel engine is provided. Through the implementation of the above-described fuel supply system for a marine ammonia fuel engine, the preheating control method includes:

[0023] S100: Before the engine is started, the A1 interface is connected to the A2 interface to form a loop between the supply heat exchanger and the electric auxiliary heat exchanger;

[0024] S200: When the ammonia fuel reaches the required temperature, the engine starts, the A1 interface is connected to the A3 interface, and the seawater is heated through the central water heat exchanger and forms a circulation between the cylinder liner water heat exchanger.

[0025] S300: The electric auxiliary heat exchanger is shut down, the central water heat exchanger stops supplying water, and a circulation is formed between the supply heat exchanger and the cylinder liner water heat exchanger;

[0026] S400: The supply heat exchanger is used to supply heated ammonia fuel to the injector and inject it into the combustion chamber of the engine.

[0027] Preferably, the preheating control method further includes a step between S300 and S400:

[0028] S310: The evaporated fresh water is replenished to the central water heat exchanger, the supply heat exchanger and the cylinder liner water heat exchanger in the heat exchange process through the expansion tank.

[0029] The beneficial effects of this invention are as follows:

[0030] The fuel supply system for a marine ammonia-fueled engine provided by this invention comprises a first feed side of a heat exchanger connected to a storage unit, and an output side of the first feed side connected to a filter. The output side of an electric auxiliary heat exchanger is connected to the input side of the first heat exchange side, and the output side of a cylinder liner water heat exchanger is also connected to the input side of the first heat exchange side. A second feed side of a central water heat exchanger is connected to a seawater source, and the input side of the second heat exchange side is connected to the output side of the cylinder liner water heat exchanger. The A1 port of a three-way valve is selectively connected to either the A2 port or the A3 port. Before starting the marine engine, the three-way valve is adjusted to create a circulation between the supply heat exchanger and the electric auxiliary heat exchanger. Ammonia fuel from the storage unit flows into the supply heat exchanger, causing the internal heat exchange medium to flow. When the heat exchange medium flows through the electric auxiliary heat exchanger, it heats the medium. The heated medium then flows back into the supply heat exchanger, transferring heat from the heat exchange medium to the ammonia fuel, thus heating the fuel before starting the marine engine. Secondly, once the ammonia fuel is heated to the required temperature, the marine engine starts, and a circulation is established between the central water-heat exchanger and the cylinder liner water-heat exchanger. The heat exchange medium, heated from the central water-heat exchanger, flows into the cylinder liner water-heat exchanger, which operates normally to meet the needs of the marine engine's normal operation and generates considerable waste heat. At this point, the electric auxiliary heat exchanger is shut off, and the three-way valve is adjusted to establish a circulation between the supply heat exchanger and the cylinder liner water-heat exchanger. The waste heat from the cylinder liner water-heat exchanger serves as a heat source for effective heat exchange with the heat exchange medium in the supply heat exchanger. The heated heat exchange medium in the supply heat exchanger exchanges heat with the ammonia fuel without requiring additional energy consumption. Finally, the heated ammonia fuel, filtered and supplied to the injector, is injected into the engine's combustion chamber.

[0031] The preheating control method for the fuel supply system of a marine ammonia-fueled engine provided by this invention involves connecting interface A1 to interface A2 before engine start-up, creating a circulation between the supply heat exchanger and the electric auxiliary heat exchanger. When the ammonia fuel reaches the required temperature, the engine starts, and interface A1 connects to interface A3. Seawater is heated through the central water heat exchanger and circulates with the cylinder liner water heat exchanger. The electric auxiliary heat exchanger is then shut off, and the central water heat exchanger stops supplying water, creating a circulation between the supply heat exchanger and the cylinder liner water heat exchanger. The supply heat exchanger provides heated ammonia fuel to the injectors and injects it into the engine's combustion chamber. This method effectively heats the ammonia fuel before and after engine start-up without requiring additional energy consumption. Attached Figure Description

[0032] Figure 1 This is a control principle diagram of the fuel supply system for a marine ammonia fuel engine provided in Embodiment 1 of the present invention;

[0033] Figure 2 This is a flowchart of a preheating control method for a marine ammonia fuel engine provided in Embodiment 2 of the present invention.

[0034] In the picture:

[0035] 1. Storage unit; 2. Filter; 3. Supply heat exchanger; 4. Electric auxiliary heat exchanger; 5. Cylinder liner water heat exchanger; 6. Central water heat exchanger; 7. Three-way valve; 8. Supply pump; 9. Ejector; 10. Expansion tank; 11. First flow valve; 12. Liquid level sensor; 13. Gas leak detector; 14. Thermostatic control valve; 15. Water pump; 16. Thermometer; 17. Second flow valve. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, in this embodiment, the fuel supply system of the marine ammonia fuel engine includes a storage unit 1, a filter 2, a supply heat exchanger 3, an electric auxiliary heat exchanger 4, a cylinder liner water heat exchanger 5, a central water heat exchanger 6, and a three-way valve 7. The supply heat exchanger 3 has a first feed side and a first heat exchange side. The input end of the first feed side is connected to the storage unit 1, and the output end of the first feed side is connected to the filter 2. The output end of the electric auxiliary heat exchanger 4 is connected to the input end of the first heat exchange side. The output end of the cylinder liner water heat exchanger 5 is connected to the input end of the first heat exchange side. The central water heat exchanger 6 has a second feed side and a second heat exchange side. The second feed side is connected to a seawater source, and the input end of the second heat exchange side is connected to the output end of the cylinder liner water heat exchanger 5. The three-way valve 7 has an A1 port, an A2 port, and an A3 port. The A1 port can be connected to one of the A2 and A3 ports. The A1 port is connected to the output end of the first heat exchange side and the output end of the second heat exchange side. The A2 port is connected to the input end of the electric auxiliary heat exchanger 4. The A3 port is connected to the input end of the cylinder liner water heat exchanger 5.

[0042] Storage unit 1 is equipped with a fuel tank for storing ammonia fuel, which has a certain capacity to ensure a continuous and stable supply of ammonia fuel. Preferably, the related equipment of storage unit 1 is made of corrosion-resistant materials and has a device for primary filtration of the ammonia fuel in storage unit 1.

[0043] Filter 2 is used to filter ammonia fuel before it enters the control unit. In the final stage before combustion, the heated ammonia fuel is first filtered through filter 2 to ensure that impurities introduced during preheating are effectively removed before the fuel enters the engine, protecting the engine's safe operation.

[0044] Ammonia fuel needs to be preheated before filtration. The preheating unit preheats the ammonia fuel supplied from storage unit 1. The preheating unit includes a supply heat exchanger 3, an electric auxiliary heat exchanger 4, a cylinder liner water heat exchanger 5, a central water heat exchanger 6, and a three-way valve 7. Both the supply heat exchanger 3 and the central water heat exchanger 6 have two input terminals and two output terminals. The two input terminals of the supply heat exchanger 3 are connected to storage unit 1 and cylinder liner water heat exchanger 5, respectively, and the two output terminals are connected to filter 2 and interface A1, respectively. The two input terminals of the central water heat exchanger 6 are connected to cylinder liner water heat exchanger 5 and seawater source, respectively, and the two output terminals are connected to interface A1 and seawater source, respectively. The electric auxiliary heat exchanger 4 electrically heats the heat exchange medium through electric assistance. Heat exchange occurs through the heat exchange medium in the connecting pipes between these heat exchangers.

[0045] First, before starting the marine engine, adjust the three-way valve 7, connecting port A1 to port A2 to create a circulation between the supply heat exchanger 3 and the electric auxiliary heat exchanger 4. At this time, the storage unit 1 is opened, and the ammonia fuel in the storage unit 1 flows into the supply heat exchanger 3, causing it to drive the internal heat exchange medium to flow. When the heat exchange medium flows through the electric auxiliary heat exchanger 4, the electric auxiliary heat exchanger 4 heats the heat exchange medium. Then, the heated heat exchange medium flows back into the supply heat exchanger 3, transferring heat from the heat exchange medium to the ammonia fuel, thus heating the fuel before starting the marine engine. Second, after the ammonia fuel is heated to the required temperature, the marine engine starts, and seawater flows into the central water heat exchanger 6. A circulation is formed between the central water heat exchanger 6 and the cylinder liner water heat exchanger 5. The heat exchange medium, heated from the central water heat exchanger 6, flows into the cylinder liner water heat exchanger 5, which operates normally to meet the needs of the marine engine's normal operation and generates a significant amount of waste heat. At this point, the electric auxiliary heat exchanger 4 is shut down, and interface A1 is connected to interface A3, creating a circulation between the supply heat exchanger 3 and the cylinder liner water heat exchanger 5. The waste heat from the cylinder liner water heat exchanger 5 serves as a heat source, replacing the electric auxiliary heat exchanger 4 to effectively exchange heat with the heat exchange medium of the supply heat exchanger 3. The heat exchange medium heated by the supply heat exchanger 3 exchanges heat with the ammonia fuel without requiring additional energy consumption. Finally, the heated ammonia fuel, filtered by filter 2, is injected into the engine's combustion chamber via the injector.

[0046] Furthermore, referring to Figure 1 The fuel supply system of the marine ammonia fuel engine also includes a supply pump 8 and an ejector 9. The input end of the supply pump 8 is connected to the storage unit 1, the input end of the ejector 9 is connected to the output end of the supply pump 8 and the output end of the filter 2, and the output end of the ejector 9 is connected to the input end of the first feed side.

[0047] The supply pump 8 is used to open or close the storage unit 1, and the ejector 9 acts as a nozzle. When a cycle is formed between the supply heat exchanger 3 and the electric auxiliary heat exchanger 4, the supply pump 8 is opened, and the ammonia fuel in the storage unit 1 enters the ejector 9. The ejector 9 increases the kinetic energy of the ammonia fuel, causing it to drive the flow of the heat exchange medium inside the supply heat exchanger 3. To improve the utilization rate of ammonia fuel, when the marine engine starts, the amount of ammonia fuel required is controlled according to the engine's speed and power at that time. At this time, the ammonia fuel that has been simply filtered by the filter 2 can be ejected by the ammonia fuel flowing through the supply pump 8, so that the two streams of ammonia fuel exchange energy and momentum in the mixing chamber of the ejector 9, thereby improving the utilization efficiency and treatment effect of ammonia fuel. Specifically, when the high-speed injected ammonia fuel enters the mixing chamber through the ejector 9, a low-pressure zone is formed in the mixing chamber, where it mixes with the ammonia fuel that has been simply filtered by the filter 2. During the mixing process, the two streams of ammonia fuel exchange energy and momentum.

[0048] Furthermore, referring to Figure 1 The fuel supply system of the marine ammonia fuel engine also includes an expansion tank 10. The input end of the expansion tank 10 is connected to an external fresh water source, and the output end of the expansion tank 10 is connected to a central water heat exchanger 6, a supply heat exchanger 3, and a cylinder liner water heat exchanger 5.

[0049] To replenish the fresh water evaporated during the heat exchange process, an expansion tank 10 is added to the connecting pipelines of the central water heat exchanger 6, the supply heat exchanger 3, and the cylinder liner water heat exchanger 5. The water in the expansion tank 10 comes from a fresh water source and is free of impurities. Specifically, it also includes a first flow valve 11 and a liquid level sensor 12 electrically connected to the first flow valve 11. The input end of the first flow valve 11 is connected to an external fresh water source, and the output end of the first flow valve 11 is connected to the expansion tank 10. The liquid level sensor 12 is installed in the expansion tank 10 and is used to detect the liquid level in the expansion tank 10 to change the valve opening of the first flow valve 11.

[0050] When the level sensor 12 detects that the liquid level in the expansion tank 10 is too low, the level sensor 12 sends a signal to the first flow valve 11 and directly controls the valve opening of the first flow valve 11 to increase, so that more fresh water enters the expansion tank 10. When the level sensor 12 detects that the liquid level in the expansion tank 10 is too high, the level sensor 12 sends a signal to the first flow valve 11 and directly controls the valve opening of the first flow valve 11 to decrease, so as to prevent the fresh water in the expansion tank 10 from overflowing due to excessive fresh water.

[0051] Preferably, the fuel supply system of the marine ammonia fuel engine also includes a gas leak detector 13, which is installed in the expansion tank 10 and used to detect whether there is ammonia fuel leakage in the expansion tank 10, so as to perform timely maintenance and protection and avoid fuel leakage from affecting the normal operation of the engine.

[0052] Furthermore, referring to Figure 1 The fuel supply system of the marine ammonia fuel engine also includes a thermostatic control valve 14 and a water pump 15. The input end of the water pump 15 is connected to a seawater source, and the output end of the water pump 15 is connected to the second feed side. The input end of the thermostatic control valve 14 is connected to the output end of the second heat exchange side, and the output end of the thermostatic control valve 14 is connected to the A1 interface.

[0053] Once the ammonia fuel is heated to the required temperature, the marine engine starts. Under the action of water pump 15, seawater flows into the central hydrothermal exchanger 6, forming a circulation between the central hydrothermal exchanger 6 and the cylinder liner hydrothermal exchanger 5. Then, the thermostatic control valve 14 is adjusted to ensure the outlet temperature of the central hydrothermal exchanger 6 reaches a set value, for example, 36°C. The heat exchange medium, heated from the central hydrothermal exchanger 6, flows into the cylinder liner hydrothermal exchanger 5, which operates normally to meet the needs of the marine engine's normal operation and generate significant waste heat.

[0054] Furthermore, referring to Figure 1 The fuel supply system of the marine ammonia fuel engine also includes a thermometer 16 and a second flow valve 17. The thermometer 16 is installed on the heat exchange side of the supply heat exchanger 3 and the central water heat exchanger 6, and is used to detect the temperature of the heat exchange medium in real time. There are multiple second flow valves 17, which are respectively installed on the first feed side, the first heat exchange side, the second feed side, and the input and output ends of the second heat exchange side.

[0055] The flow rate of the heat exchange medium in the central water heat exchanger 6 and the supply heat exchanger 3 is controlled by adjusting the opening and closing angles of the second flow valves 17 on each connecting pipeline. The temperature of the heat exchange medium is displayed by the thermometer 16. By changing the temperatures of the electric auxiliary heat exchanger 4 and the thermostatic control valve 14, the heating temperature of the ammonia fuel during the preheating process is adjusted, thereby ensuring the temperature stability of the ammonia fuel and avoiding overheating or overcooling, thus improving combustion efficiency and safety. In addition, the operating parameters of the preheating unit can be optimized through data recording and analysis to further improve the preheating effect of the system.

[0056] The ammonia fuel control unit ensures precise control and management of the ammonia fuel throughout the supply system, maintaining its normal operation and safety. The control unit should include at least a temperature gauge, a pressure gauge, and a safety valve. The temperature gauge directly acquires the temperature data of the ammonia fuel after preheating, allowing for timely adjustments to the system's operating status and ensuring the ammonia fuel enters subsequent processing stages at the appropriate temperature. The pressure gauge monitors the system pressure, ensuring it remains within a safe range and providing real-time data to help the control system determine if pressure regulation is necessary, preventing excessively high or low pressures from affecting system operation. The safety valve releases pressure when the system pressure exceeds a set value, preventing equipment damage or other safety accidents caused by excessive pressure.

[0057] The control unit can be equipped with multiple sensors, each installed on different pipelines within the control unit, to monitor the flow status of ammonia fuel in real time and issue alarms when abnormalities occur. By integrating multiple sensors, including but not limited to flow sensors, temperature sensors, pressure sensors, and level sensors, the system can monitor the flow status of ammonia fuel in the pipeline in real time, including but not limited to parameters such as flow rate, temperature, and pressure. This real-time monitoring data is crucial for maintaining the normal operation of the fuel supply system.

[0058] The supply unit, connected to the control unit, delivers filtered and metered ammonia fuel to the injectors, which then inject the ammonia fuel into the combustion chamber of the marine engine. A pressure pump and an ammonia skid can be added to the supply unit. The pressure pump helps overcome the internal pressure of the combustion chamber and ensures adequate fuel atomization, thereby ensuring efficient and uniform combustion. The ammonia skid, connected to multiple injectors, distributes the ammonia fuel to different combustion chambers.

[0059] Storage unit 1 is responsible for the storage and supply of ammonia fuel, ensuring a stable fuel delivery to the preheating unit. Before the preheated ammonia fuel enters the engine, the filtration unit filters and cleans it, making the fuel cleaner and preventing engine malfunctions caused by impurities. This not only protects the engine and extends the service life of the equipment but also improves the stability of the fuel supply. The control unit can monitor the operating status of the ammonia fuel in real time, ensuring that the fuel is in optimal condition at each stage, further enhancing the system's reliability. Simultaneously, when the system detects abnormal pressure or temperature, the safety valve automatically releases pressure to prevent accidents.

[0060] Example 2

[0061] like Figure 2 As shown, in this embodiment, through the implementation of the above-described marine ammonia fuel engine fuel supply system, the preheating control method includes the following steps:

[0062] S100: Before the engine starts, the A1 interface is connected to the A2 interface to form a loop between the supply heat exchanger 3 and the electric auxiliary heat exchanger 4.

[0063] Before starting the marine engine, adjust the three-way valve 7, connecting port A1 to port A2 to create a circulation between the supply heat exchanger 3 and the electric auxiliary heat exchanger 4. At this time, open storage unit 1, and the ammonia fuel in storage unit 1 flows into the supply heat exchanger 3, causing it to drive the internal heat exchange medium to flow. When the heat exchange medium flows through the electric auxiliary heat exchanger 4, the electric auxiliary heat exchanger 4 heats the heat exchange medium. Then, the heated heat exchange medium flows back into the supply heat exchanger 3, transferring heat from the heat exchange medium to the ammonia fuel, thus achieving fuel heating before starting the marine engine.

[0064] S200: When the ammonia fuel reaches the required temperature, the engine starts, the A1 interface connects to the A3 interface, and the seawater is heated through the central water heat exchanger 6 and forms a circulation between the seawater and the cylinder liner water heat exchanger 5.

[0065] Once the ammonia fuel is heated to the required temperature, the marine engine starts, and seawater flows into the central hydrothermal exchanger 6. A circulation is formed between the central hydrothermal exchanger 6 and the cylinder liner hydrothermal exchanger 5. The heat exchange medium is heated from the central hydrothermal exchanger 6 and flows into the cylinder liner hydrothermal exchanger 5. The cylinder liner hydrothermal exchanger 5 operates normally to meet the needs of the marine engine's normal operation and generates a significant amount of waste heat.

[0066] S300: The electric auxiliary heat exchanger 4 is turned off, the central water heat exchanger 6 stops supplying water, and a circulation is formed between the supply heat exchanger 3 and the cylinder liner water heat exchanger 5.

[0067] With the electric auxiliary heat exchanger 4 shut off, the A1 interface is connected to the A3 interface, creating a circulation between the supply heat exchanger 3 and the cylinder liner water heat exchanger 5. The waste heat from the cylinder liner water heat exchanger 5 serves as a heat source, replacing the electric auxiliary heat exchanger 4 to effectively exchange heat with the heat exchange medium of the supply heat exchanger 3. The heat exchange medium heated by the supply heat exchanger 3 exchanges heat with the ammonia fuel, requiring no additional energy consumption.

[0068] S310: The evaporated fresh water is supplied to the central water heat exchanger 6, the supply heat exchanger 3 and the cylinder liner water heat exchanger 5 in the heat exchange process through the expansion tank 10.

[0069] To replenish the fresh water evaporated during the heat exchange process, an expansion tank 10 is added to the connecting pipelines of the central water heat exchanger 6, the supply heat exchanger 3, and the cylinder liner water heat exchanger 5. When the level sensor 12 detects that the liquid level in the expansion tank 10 is too low, the level sensor 12 sends a signal to the first flow valve 11 and directly controls the valve opening of the first flow valve 11 to increase, so that more fresh water enters the expansion tank 10. When the level sensor 12 detects that the liquid level in the expansion tank 10 is too high, the level sensor 12 sends a signal to the first flow valve 11 and directly controls the valve opening of the first flow valve 11 to decrease, so as to prevent the fresh water in the expansion tank 10 from overflowing due to excessive fresh water.

[0070] S400: Supply heat exchanger 3 to provide heated ammonia fuel to the injector and inject it into the engine's combustion chamber.

[0071] After being filtered by filter 2, heated ammonia fuel is injected into the engine's combustion chamber via the injector.

[0072] The preheating control method for the fuel supply system of a marine ammonia-fueled engine provided in this embodiment achieves the following: Before engine start-up, interface A1 is connected to interface A2, creating a circulation between the supply heat exchanger 3 and the electric auxiliary heat exchanger 4. When the ammonia fuel reaches the required temperature, the engine starts, interface A1 is connected to interface A3, and seawater is heated through the central water heat exchanger 6 and circulates with the cylinder liner water heat exchanger 5. The electric auxiliary heat exchanger 4 is then shut off, and the central water heat exchanger 6 stops supplying water, creating a circulation between the supply heat exchanger 3 and the cylinder liner water heat exchanger 5. The supply heat exchanger 3 provides heated ammonia fuel to the injectors and injects it into the engine's combustion chamber. This method effectively heats the ammonia fuel before and after engine start-up without requiring additional energy consumption.

[0073] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fuel supply system for a marine ammonia fuel engine, characterized in that The ship ammonia fuel engine fuel supply system comprises a storage unit (1), a filter (2), a supply heat exchanger (3) having a first feeding side and a first heat exchanging side, an input end of the first feeding side being connected to the storage unit (1), an output end of the first feeding side being connected to the filter (2), an electric auxiliary heat exchanger (4) having an output end connected to an input end of the first heat exchanging side, a cylinder liner water heat exchanger (5) having an output end connected to an input end of the first heat exchanging side, a central water heat exchanger (6) having a second feeding side and a second heat exchanging side, the second feeding side being connected to a seawater source, an input end of the second heat exchanging side being connected to an output end of the cylinder liner water heat exchanger (5), a three-way valve (7) having an A1 interface, an A2 interface and an A3 interface, the A1 interface being in communication with the A2 interface and the A3 interface alternatively, the A1 interface being connected to an output end of the first heat exchanging side and an output end of the second heat exchanging side, the A2 interface being connected to an input end of the electric auxiliary heat exchanger (4), the A3 interface being connected to an input end of the cylinder liner water heat exchanger (5). The ship ammonia fuel engine fuel supply system further comprises a supply pump (8) having an input end connected to the storage unit (1), and an ejector (9) having an input end connected to an output end of the supply pump (8) and an output end of the filter (2), and an output end connected to an input end of the first feeding side. The ship ammonia fuel engine fuel supply system further comprises an expansion water tank (10) having an input end connected to an external fresh water source, and an output end connected to the central water heat exchanger (6), the supply heat exchanger (3) and the cylinder liner water heat exchanger (5). The ship ammonia fuel engine fuel supply system further comprises a first flow valve (11) having an input end connected to an external fresh water source, and an output end connected to the expansion water tank (10), and a liquid level sensor (12) electrically connected to the first flow valve (11), the liquid level sensor (12) being arranged in the expansion water tank (10) and being used to detect a liquid level of the expansion water tank (10) so as to change a valve opening degree of the first flow valve (11). The ship ammonia fuel engine fuel supply system further comprises a gas leakage detector (13) arranged in the expansion water tank (10) and being used to detect whether there is ammonia fuel leakage in the expansion water tank (10). ​ ​ ​ 2. The fuel supply system of the marine ammonia fuel engine according to claim 1, characterized by, ​ 3. The fuel supply system of the marine ammonia fuel engine according to claim 1, characterized by, ​ 4. The fuel supply system of the marine ammonia fuel engine according to claim 3, characterized by, ​ 5. The fuel supply system of the marine ammonia fuel engine according to claim 3, characterized by, ​ 6. The fuel supply system of the marine ammonia fuel engine according to claim 1, characterized by, The fuel supply system of the marine ammonia fuel engine further comprises a thermostatic control valve (14) and a water pump (15), the input end of the water pump (15) is connected to a seawater source, the output end of the water pump (15) is connected to the second feeding side, the input end of the thermostatic control valve (14) is connected to the output end of the second heat exchange side, and the output end of the thermostatic control valve (14) is connected to the A1 interface.

7. The fuel supply system of the marine ammonia fuel engine according to claim 1, characterized by, The fuel supply system of the marine ammonia fuel engine further comprises a thermometer (16) arranged on the heat exchange side of the supply heat exchanger (3) and the central water heat exchanger (6) and used for detecting the temperature of the heat exchange medium in real time.

8. The fuel supply system of the marine ammonia fuel engine according to claim 1, characterized by, The fuel supply system of the marine ammonia fuel engine further comprises a plurality of second flow valves (17), and each of the plurality of second flow valves (17) is arranged at the input end and the output end of the first feeding side, the first heat exchange side, the second feeding side and the second heat exchange side.

9. A fuel supply system preheating control method for a marine ammonia fuel engine, characterized by, Through the implementation of the fuel supply system of the marine ammonia fuel engine according to any one of claims 1-8, the preheating control method comprises: S100: before starting the engine, the A1 interface is connected to the A2 interface, so that a circulation is formed between the supply heat exchanger (3) and the electric auxiliary heat exchanger (4); S200: when the ammonia fuel reaches the temperature requirement, the engine is started, the A1 interface is connected to the A3 interface, seawater is heated by the central water heat exchanger (6) and forms a circulation with the cylinder liner water heat exchanger (5); S300: the electric auxiliary heat exchanger (4) is closed, the central water heat exchanger (6) stops water supply, and a circulation is formed between the supply heat exchanger (3) and the cylinder liner water heat exchanger (5); S400: the supply heat exchanger (3) is used to provide heated ammonia fuel to the injector and inject the heated ammonia fuel into the combustion chamber of the engine.

10. The fuel supply system preheating control method of the marine ammonia fuel engine according to claim 9, characterized by, The fuel supply system of the marine ammonia fuel engine further comprises an expansion water tank (10), the input end of the expansion water tank (10) is connected to an external fresh water source, and the output end of the expansion water tank (10) is connected to the central water heat exchanger (6), the supply heat exchanger (3) and the cylinder liner water heat exchanger (5); The preheating control method further comprises, between S300 and S400: S310: the expansion water tank (10) is used to supplement the evaporated fresh water to the central water heat exchanger (6), the supply heat exchanger (3) and the cylinder liner water heat exchanger (5) in the heat exchange process.

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