Fuel supply system for marine ammonia fuel engine and control method thereof

Abstract

The application discloses a fuel supply system of a marine ammonia fuel engine and a control method thereof, and can be applied to the technical field of fuel supply. The application sets a liquid ammonia storage tank, a first low-pressure pump, a first pressure sensor, a heater, a pressure stabilizing module, a second pressure sensor, a filter, a high-pressure pump, a heat exchanger and a second buffer tank in the supply system, sets a first buffer tank, a reversing valve, a gas-liquid separator, a pressure regulating valve and a liquefier in the pressure stabilizing module, and controls the pressure stabilizing working process through the difference between the output power of the ship engine and the first pressure value collected by the first pressure sensor and the second pressure value collected by the second pressure sensor, so that the working stability of the ammonia fuel supply system of the ship engine can be effectively improved, the ammonia fuel state input into the ammonia fuel engine meets the demand of the engine, and the working stability of the ship is improved.

Description

Technical Field

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

[0002] In related technologies, existing control and regulation methods for ammonia fuel supply systems of marine engines monitor the flow rate, pressure, and temperature of ammonia fuel in the liquid ammonia fuel supply pipeline through sensors and control systems, and adjust the system's flow rate, pressure, and heating devices based on these parameters. However, the pressure control of the supply system often employs a series connection of low-pressure and high-pressure pumps for liquid supply. When the engine load is adjusted, especially from cold start to low-load operation or from medium-high load to high-load operation, the demand for ammonia fuel increases rapidly. This can easily cause large changes in the flow rate in the pipelines between the low-pressure and high-pressure pumps, and between the high-pressure pump and the engine, leading to pipeline pressure fluctuations and ultimately causing abnormal system operation.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0004] The main objective of this application is to propose a fuel supply system and control method for an ammonia fuel engine, which can effectively improve the operational stability of the ammonia fuel supply system for a ship engine.

[0005] To achieve the above objectives, one aspect of this application provides a fuel supply system for a marine ammonia-fueled engine, the system comprising:

[0006] A liquid ammonia storage tank, wherein the liquid ammonia storage tank is used to store liquid ammonia;

[0007] A first low-pressure pump, the input end of which is connected to the first output end of the liquid ammonia storage tank;

[0008] A first pressure sensor is disposed at the output end of the first low-pressure pump and is used to detect a first pressure value at the output end of the first low-pressure pump.

[0009] A heater, the first end of which is connected to the output end of the first low-pressure pump;

[0010] A pressure stabilizing module includes a first buffer tank, a reversing valve, a gas-liquid separator, a pressure regulating valve, and a liquefier. The input end of the first buffer tank is connected to the output end of the heater. The output end of the first buffer tank is connected to the first end of the reversing valve. The second end of the reversing valve is connected to the output end of the pressure regulating valve and serves as the output end of the pressure stabilizing module. The third end of the reversing valve is connected to the input end of the gas-liquid separator. The gaseous ammonia output end of the gas-liquid separator is connected to the input end of the liquefier. The liquid ammonia output end of the gas-liquid separator is connected to the input end of the pressure regulating valve. The output end of the liquefier is connected to the input end of the liquid ammonia storage tank.

[0011] The second pressure sensor is disposed at the output terminal of the voltage regulator module and is used to detect the second pressure value at the output terminal of the voltage regulator module.

[0012] A filter, the input end of which is connected to the output end of the voltage regulator module;

[0013] A high-pressure pump, the input end of which is connected to the output end of the filter;

[0014] A heat exchanger, the input end of which is connected to the output end of the high-pressure pump;

[0015] The second buffer tank has its input end connected to the output end of the heat exchanger, and its output end connected to the ammonia fuel engine.

[0016] The operating state of the pressure stabilizing module is controlled by the output power of the ship's engine or the difference between the first pressure value and the second pressure value.

[0017] In some embodiments, the system further includes:

[0018] A first temperature sensor is disposed at the input terminal of the heater;

[0019] A second temperature sensor is disposed at the input end of the high-pressure pump;

[0020] A third temperature sensor is disposed at the output end of the high-pressure pump;

[0021] A fourth temperature sensor is disposed at the input end of the second buffer tank.

[0022] In some embodiments, the system further includes a first check valve;

[0023] The first end of the first check valve is connected to the output end of the first low-pressure pump, and the second end of the first check valve is connected to the input end of the heater.

[0024] In some embodiments, the system further includes a second low-pressure pump and a second check valve;

[0025] The input end of the second low-pressure pump is connected to the second output end of the liquid ammonia storage tank, the output end of the second low-pressure pump is connected to the first end of the second check valve, and the second end of the second check valve is connected to the input end of the heater.

[0026] In some embodiments, the system further includes a first regulating valve and a second regulating valve;

[0027] The first regulating valve is located on the connecting pipeline between the first output end of the liquid ammonia storage tank and the input end of the first low-pressure pump;

[0028] The second regulating valve is located on the connecting pipeline between the second output end of the liquid ammonia storage tank and the input end of the second low-pressure pump.

[0029] In some embodiments, the system further includes a third check valve;

[0030] The first end of the third check valve is connected to the output end of the liquefier, and the second end of the third check valve is connected to the input end of the liquid ammonia storage tank.

[0031] In some embodiments, the system further includes a loop regulating valve, a fourth check valve, and a pressure reducing valve;

[0032] The first end of the circuit regulating valve is connected to the input end of the heater, and the second end of the circuit regulating valve is connected to the first end of the fourth check valve.

[0033] The second end of the fourth check valve is connected to the first end of the pressure reducing valve;

[0034] The second end of the pressure reducing valve is connected to the input end of the liquid ammonia storage tank.

[0035] In some embodiments, the system further includes a third pressure sensor and a fourth pressure sensor;

[0036] The third pressure sensor is located at the input end of the high-pressure pump;

[0037] The fourth pressure sensor is located at the input end of the second buffer tank.

[0038] To achieve the above objectives, another aspect of this application proposes a control method for a fuel supply system of the aforementioned marine ammonia fuel engine, the method comprising the following steps:

[0039] Obtain the ship's current navigation status;

[0040] The current output power of the ship's engine is obtained based on the ship's current navigation conditions;

[0041] When it is determined that the current output power is within the first preset range or the second range, the working state of the voltage regulator module is controlled to adjust the pressure of the ammonia fuel input into the engine;

[0042] When it is determined that the current output power is not within the first preset range or the second range, the first pressure value collected by the first pressure sensor and the second pressure value collected by the second pressure sensor are obtained.

[0043] Calculate the difference between the first pressure value and the second pressure value;

[0044] When the difference is less than the pressure threshold, the working state of the pressure stabilizing module is controlled to adjust the pressure of the ammonia fuel input into the engine.

[0045] In some embodiments, the method further includes the following steps:

[0046] Obtain the first temperature value collected by the first temperature sensor;

[0047] Adjust the preheating temperature of the ammonia fuel in the heater according to the first temperature value;

[0048] Acquire the second temperature value collected by the second temperature sensor;

[0049] When the second temperature value is less than the first temperature threshold, the preheating temperature of the ammonia fuel by the heater is fed back again.

[0050] When the second temperature value is greater than or equal to the first temperature threshold, the third temperature value collected by the third temperature sensor is obtained;

[0051] The influence of the high-pressure pump on the ammonia fuel temperature is analyzed based on the second and third temperature values.

[0052] Obtain the fourth temperature value collected by the fourth temperature sensor;

[0053] The heating process of liquid ammonia by the heat exchanger is adjusted according to the fourth temperature value.

[0054] The embodiments of this application include at least the following beneficial effects: This application provides a fuel supply system and control method for a marine ammonia fuel engine. This solution sets up a liquid ammonia storage tank, a first low-pressure pump, a first pressure sensor, a heater, a pressure stabilizing module, a second pressure sensor, a filter, a high-pressure pump, a heat exchanger, and a second buffer tank in the supply system. After setting up a first buffer tank, a reversing valve, a gas-liquid separator, a pressure regulating valve, and a liquefier in the pressure stabilizing module, the pressure stabilization process is controlled by the output power of the marine engine or the difference between the first pressure value collected by the first pressure sensor and the second pressure value collected by the second pressure sensor. This can effectively improve the working stability of the marine engine ammonia fuel supply system, so that the state of the ammonia fuel input into the ammonia fuel engine meets the engine's requirements, thereby improving the ship's working stability. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the fuel supply system for a marine ammonia fuel engine provided in an embodiment of this application;

[0056] Figure 2 This application provides a control method for a fuel supply system of a marine ammonia fuel engine.

[0057] Figure 3 This application provides another method for controlling the fuel supply system of a marine ammonia fuel engine. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application.

[0059] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0060] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0062] Among related technologies, ammonia, as a clean energy source and carbon-free fuel, is easy to pressurize, store, and transport, and has a wide range of sources. It can be produced through coal and natural gas cracking, or through the catalytic synthesis of green ammonia from renewable energy sources such as wind and solar power, resulting in low cost. Ammonia can be used in single-fuel or dual-fuel engines. Liquid ammonia injection can solve the problem of reduced charging efficiency caused by the low energy density of gaseous ammonia. Currently, MAN and Hyundai Heavy Industries (HD) are planning to develop a high-pressure direct injection ammonia / diesel dual-fuel engine, which can utilize biodiesel micro-ignition to further improve the ammonia substitution rate and achieve zero carbon emissions for ships. In ammonia-fueled engines, the injection quantity of liquid ammonia is controlled by an injection control system and liquid ammonia nozzles, but changes in engine load can cause fluctuations in pipeline pressure, thus affecting fuel supply.

[0063] Existing control and regulation methods for marine engine ammonia fuel supply systems monitor the flow rate, pressure, and temperature of ammonia fuel in the liquid ammonia fuel supply pipeline using sensors and control systems, and adjust the system's flow rate, pressure, and heating devices accordingly. However, the pressure control of the supply system often employs a series connection of low-pressure and high-pressure pumps for liquid supply. When the engine load is adjusted, especially from cold start to low-load operation or from medium-high load to high-load operation, the demand for ammonia fuel increases rapidly. This can easily cause large changes in the flow rate in the pipelines between the low-pressure and high-pressure pumps, and between the high-pressure pump and the engine, leading to pipeline pressure fluctuations and ultimately causing system malfunctions.

[0064] In view of this, this application provides a fuel supply system and control method for a marine ammonia fuel engine. This application provides a liquid ammonia storage tank, a first low-pressure pump, a first pressure sensor, a heater, a pressure stabilizing module, a second pressure sensor, a filter, a high-pressure pump, a heat exchanger, and a second buffer tank in the supply system. The pressure stabilizing module includes a first buffer tank, a reversing valve, a gas-liquid separator, a pressure regulating valve, and a liquefier. The pressure stabilization process is controlled by the output power of the marine engine or the difference between the first pressure value collected by the first pressure sensor and the second pressure value collected by the second pressure sensor. This effectively improves the operational stability of the marine engine ammonia fuel supply system, ensuring that the state of the ammonia fuel input to the ammonia fuel engine meets the engine's requirements, thereby improving the ship's operational stability.

[0065] The embodiments of this application will be described in detail below with reference to the accompanying drawings:

[0066] Reference Figure 1 This application provides a fuel supply system for a marine ammonia fuel engine. The system includes a liquid ammonia storage tank 100, a first low-pressure pump 111, a first pressure sensor 131, a heater 121, a pressure stabilizing module 140, a second pressure sensor 132, a filter 160, a high-pressure pump 113, a heat exchanger 122, and a second buffer tank 152. The liquid ammonia storage tank 100 stores liquid ammonia. The input end of the first low-pressure pump 111 is connected to the first output end of the liquid ammonia storage tank 100 to pressurize the liquid ammonia output from the storage tank. The first pressure sensor 131 is located at the output end of the first low-pressure pump 111 to detect the first pressure value at the pump's output. The first end of the heater 121 is connected to the output end of the first low-pressure pump 111 to heat the liquid ammonia. The second pressure sensor 132 is located at the output end of the pressure stabilizing module 140 to detect the pressure value of the pump. The second pressure value at the output end; the input end of filter 160 is connected to the output end of pressure stabilizing module 140 for filtering gaseous ammonia flowing through pressure stabilizing module; the input end of high pressure pump 113 is connected to the output end of filter for pressurizing ammonia output from filter again; the input end of heat exchanger 122 is connected to the output end of high pressure pump 113 for heating liquid ammonia output from high pressure pump; the input end of second buffer tank 152 is connected to the output end of heat exchanger 122 for providing ammonia fuel with stable pressure and temperature to ammonia fuel engine 170.

[0067] It is understood that the pressure stabilizing module includes a first buffer tank 151, a reversing valve 141, a gas-liquid separator 142, a pressure regulating valve 143, and a liquefier 144. The input end of the first buffer tank 151 is connected to the output end of the heater, the output end of the first buffer tank 151 is connected to the first end of the reversing valve, the second end of the reversing valve 141 is connected to the output end of the pressure regulating valve 143 and serves as the output end of the pressure stabilizing module, the third end of the reversing valve 141 is connected to the input end of the gas-liquid separator 142, the gaseous ammonia output end of the gas-liquid separator 142 is connected to the input end of the liquefier 144, the liquid ammonia output end of the gas-liquid separator 142 is connected to the input end of the pressure regulating valve 143, and the output end of the liquefier 144 is connected to the input end of the liquid ammonia storage tank 100. The operating state of the pressure stabilizing module is controlled by the output power of the ship's engine or the difference between the first pressure value and the second pressure value.

[0068] In the embodiments of this application, such as Figure 1As shown, the system also includes a first check valve 191, a second low-pressure pump 112, a second check valve 192, a first regulating valve 411, and a second regulating valve 412. The first end of the first check valve 191 is connected to the output end of the first low-pressure pump 111, and the second end of the first check valve 191 is connected to the input end of the heater 121. The input end of the second low-pressure pump 112 is connected to the second output end of the liquid ammonia storage tank 100, and the output end of the second low-pressure pump 112 is connected to the first end of the second check valve 192, and the second end of the second check valve 192 is connected to the input end of the heater 121. The first regulating valve 411 is located on the connecting pipeline between the first output end of the liquid ammonia storage tank 100 and the input end of the first low-pressure pump 111. The second regulating valve 412 is located on the connecting pipeline between the second output end of the liquid ammonia storage tank 100 and the input end of the second low-pressure pump 112.

[0069] Based on the above Figure 1 The structure allows the pressure stabilizing module to activate its operating mode when the engine is in a cold start to low load operation condition, a medium-high load to high load operation condition, or when the pressure difference between the first pressure sensor and the second pressure sensor is greater than 2 bar. Specifically, the reversing valve in the pressure stabilizing module is connected to the gas-liquid separator pipeline, while the straight-through pipeline between the reversing valve and the filter is cut off. Liquid ammonia is pumped from a liquid ammonia storage tank to a heater to preheat it to 20°C via a first and second regulating valve, pressurized to 10 bar by a first and second low-pressure pump. The preheated liquid ammonia then passes through a first buffer tank and a reversing valve to a gas-liquid separator, separating liquid and gaseous ammonia and ensuring sufficient filling rate of the liquid ammonia fuel in the pipeline after the pressure stabilization module. This significantly reduces the impact of pressure fluctuations in the initial stage of liquid ammonia pressure regulation. The gaseous ammonia fuel is then converted to liquid ammonia by a liquefier and returned to the liquid ammonia storage tank for liquid ammonia recovery. A pressure regulating valve ensures that the liquid ammonia fuel pressure at the gas-liquid separator outlet is 10 bar, guaranteeing sufficient back pressure within the separator. The liquid ammonia fuel is then pressurized to 50 bar by a high-pressure pump via a filter and pumped to a heat exchanger. After heat exchange, the liquid ammonia fuel reaches 45°C, meeting the engine's operating requirements. The heated liquid ammonia fuel is then pumped to the ammonia-fueled engine via a second buffer tank.

[0070] When the engine is operating stably under typical conditions or under varying loads, the pressure difference between the first and second pressure sensors is less than 2 bar, indicating that the fuel supply system of the marine ammonia fuel engine is in a stable operating state. The direct connection between the reversing valve and the filter in the pressure stabilizing module is connected, while the connection between the reversing valve and the gas-liquid separator is disconnected. Liquid ammonia is pumped from the liquid ammonia storage tank, pressurized to 10 bar via the first and second regulating valves and the first and second low-pressure pumps, to the heater for preheating to 20°C. The preheated liquid ammonia then passes through the first buffer tank, the reversing valve (three-way valve), the filter, and the high-pressure pump, where it is pressurized to 50 bar and delivered to the heat exchanger. After heat exchange, the liquid ammonia reaches 45°C, meeting the engine's operating requirements. The heated liquid ammonia is then pumped to the ammonia fuel engine via the second buffer tank.

[0071] In the embodiments of this application, Figure 1 The system also includes a third check valve 193; the first end of the third check valve 193 is connected to the output end of the liquefier 144, and the second end of the third check valve 193 is connected to the input end of the liquid ammonia storage tank 100. Specifically, the third check valve is used to regulate the flow rate of liquid ammonia in the connecting pipeline between the liquid ammonia storage tank and the liquefier.

[0072] In the embodiments of this application, Figure 1 The system also includes a loop regulating valve 420, a fourth check valve 194, and a pressure reducing valve 430. The first end of the loop regulating valve 420 is connected to the input end of the heater 121, and the second end of the loop regulating valve 420 is connected to the first end of the fourth check valve 194. The second end of the fourth check valve 194 is connected to the first end of the pressure reducing valve 430, and the second end of the pressure reducing valve 430 is connected to the input end of the liquid ammonia storage tank 100. Specifically, the loop regulating valve, the fourth check valve, and the pressure reducing valve form a loop with the liquid ammonia storage tank and the low-pressure pump, thereby adjusting the flow rate of liquid ammonia output from the low-pressure pump to the heater to further maintain the stability of the system operation.

[0073] In the embodiments of this application, Figure 1 The system shown also includes a third pressure sensor 133 and a fourth pressure sensor 134; the third pressure sensor 133 is located at the input end of the high-pressure pump 113 and is used to detect the ammonia pressure value input to the high-pressure pump after passing through the filter; the fourth pressure sensor 134 is located at the input end of the second buffer tank 152 and is used to detect the ammonia pressure value input to the second buffer tank from the heat exchanger.

[0074] In the embodiments of this application, Figure 1The system also includes a first temperature sensor 181, a second temperature sensor 182, a third temperature sensor 183, and a fourth temperature sensor 184. The first temperature sensor is located at the input end of the heater; the second temperature sensor is located at the input end of the high-pressure pump; the third temperature sensor is located at the output end of the high-pressure pump; and the fourth temperature sensor is located at the input end of the second buffer tank. It is understood that in this embodiment, the first temperature sensor can be used to adjust the preheating temperature of the ammonia fuel by the heater, ensuring that the liquid ammonia delivered by the first or second low-pressure pump reaches a temperature of 20°C, and this is monitored by the second temperature sensor. The third temperature sensor monitors the outlet temperature of the high-pressure pump and feeds it back to the heat exchanger. Simultaneously, the comparison between the second and third temperature sensors confirms the degree of influence of the high-pressure pump on the heating temperature of the liquid ammonia fuel, which is then fed back to the heat exchanger, improving the responsiveness of the heating process. The fourth temperature sensor provides feedback to adjust the heating temperature of the liquid ammonia in the heat exchanger to 45°C, thereby meeting the engine's operating requirements.

[0075] based on Figure 1 The system shown is as follows: Figure 2 As shown, embodiments of this application provide Figure 1 The control method of the system shown is applicable to the electronic control unit (ECU) of a ship.

[0076] Reference Figure 2 The method in this embodiment includes, but is not limited to, the following steps:

[0077] Step S210: Obtain the ship's current navigation status;

[0078] Step S220: Obtain the current output power of the ship's engine based on the ship's current navigation conditions;

[0079] Step S230: Determine whether the current output power P is within the first preset range or the second range. If yes, proceed to step S270; otherwise, proceed to step S240.

[0080] Step S240: Obtain the first pressure value collected by the first pressure sensor and the second pressure value collected by the second pressure sensor;

[0081] Step S250: Calculate the difference between the first pressure value and the second pressure value;

[0082] Step S260: Determine whether the difference is less than the pressure threshold. If so, proceed to step S270.

[0083] Step S270: Control the working state of the pressure stabilizing module to adjust the pressure of the ammonia fuel input into the engine.

[0084] It is understandable that the first preset range can be 0-10% of the engine's full power, and the second preset range can be 75%-100% of the engine's full power. If the current output power is between 0-10% of the engine's full power, it can be determined that the engine is in a cold start to low-load operation condition; if the current output power is between 75%-100% of the engine's full power, it can be determined that the engine is in a medium-high load to high-load operation condition. Both of these operating condition changes can easily cause large changes in the flow rate in the pipelines between the low-pressure pump and the high-pressure pump, and between the high-pressure pump and the engine. This embodiment, by controlling the working state of the pressure stabilizing module, can effectively and significantly reduce the impact of pressure fluctuations in the initial stage of liquid ammonia pressure regulation.

[0085] In this embodiment, when the difference between the first pressure value and the second pressure value is too large, it can be determined that there is a significant change in engine load. At this time, the stable supply of liquid ammonia fuel can also be achieved by controlling the working state of the pressure stabilizing module. Specifically, since when the engine is running under typical load conditions, if there is a load adjustment, such as increasing from 25% of the engine's full power to 75% of the engine's full power, and the liquid ammonia fuel supply pressure after being pressurized by the low-pressure pump is 10 bar, it is estimated that there will be a pressure fluctuation of 0.5 to 5 bar based on relevant experience and data from papers. Therefore, this embodiment can set a pressure threshold of 2 bar as the judgment boundary to improve responsiveness.

[0086] In the embodiments of this application, such as Figure 3 As shown, the method in this embodiment also includes, but is not limited to, the following steps:

[0087] Step S310: Obtain the first temperature value collected by the first temperature sensor;

[0088] Step S320: Determine whether the first temperature value is less than the first temperature threshold. If yes, proceed to step S330; otherwise, proceed to step S340.

[0089] Step S330: Control the heater to perform an action to heat the liquid ammonia to the first temperature threshold (20°C);

[0090] Step S340: Obtain the second temperature value collected by the second temperature sensor;

[0091] Step S350: Determine whether the second temperature value is greater than or equal to the first temperature threshold. If yes, proceed to step S360; otherwise, proceed to step S330.

[0092] Step S360: Obtain the third temperature value collected by the third temperature sensor;

[0093] Step S370: Analyze the influence of the high-pressure pump on the ammonia fuel temperature based on the second and third temperature values, and control the heat exchanger to perform actions to heat the liquid ammonia.

[0094] Step S380: Obtain the fourth temperature value collected by the fourth temperature sensor;

[0095] Step S390: Determine whether the fourth temperature value is within the range of the second temperature threshold (45℃±3℃). If yes, determine that the liquid ammonia temperature meets the engine operation requirements; otherwise, proceed to step S370.

[0096] It is understandable that, since the preheated liquid ammonia fuel in this embodiment is pressurized by a high-pressure pump, it will heat the fuel and cause the heat exchanger to adjust sluggishly. Under high load operation, it will amplify temperature fluctuations. Therefore, this embodiment uses a third temperature sensor to feed back to the heat exchanger. At the same time, by comparing the second and third temperature sensors, it confirms the degree of influence of the high-pressure pump on fuel heating and feeds it back to the heat exchanger. This can improve the responsiveness of the heating process. In addition, the power demand of the heating process can be controlled by combining the heater outlet temperature of the fourth temperature sensor.

[0097] In summary, the embodiments of this application can ensure stable pipeline pressure after the low-pressure pump and liquefaction and recovery of ammonia gas. It significantly reduces the impact of pressure fluctuations in the initial stage of liquid ammonia pressure regulation and adjusts the heat exchanger heating temperature according to the temperature sensor. This can effectively solve the problem of high-pressure pumps being unable to cope with fluctuations in ammonia fuel supply, and also solve the problem of continuous temperature rise of ammonia fuel during the supply process, which causes sluggish response of the heat exchanger, thus ensuring stable delivery of ammonia fuel to the engine.

[0098] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0099] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0100] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0101] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0102] The terms "first," "second," "third," "fourth," etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0103] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0104] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0105] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0106] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A fuel supply system for a marine ammonia fuel engine, characterized in that The system comprises: a liquid ammonia storage tank for storing liquid ammonia; a first low-pressure pump, an input end of which is connected to a first output end of the liquid ammonia storage tank; a first pressure sensor arranged at an output end of the first low-pressure pump for detecting a first pressure value of the output end of the first low-pressure pump; a heater, a first end of which is connected to the output end of the first low-pressure pump; a pressure stabilizing module, which comprises a first buffer tank, a reversing valve, a gas-liquid separator, a pressure regulating valve and a liquefier; an input end of the first buffer tank is connected to an output end of the heater, an output end of the first buffer tank is connected to a first end of the reversing valve, a second end of the reversing valve is connected to an output end of the pressure regulating valve and serves as an output end of the pressure stabilizing module, a third end of the reversing valve is connected to an input end of the gas-liquid separator, a gas ammonia output end of the gas-liquid separator is connected to an input end of the liquefier, a liquid ammonia output end of the gas-liquid separator is connected to an input end of the pressure regulating valve, and an output end of the liquefier is connected to an input end of the liquid ammonia storage tank; a second pressure sensor arranged at the output end of the pressure stabilizing module for detecting a second pressure value of the output end of the pressure stabilizing module; a filter, an input end of which is connected to the output end of the pressure stabilizing module; a high-pressure pump, an input end of which is connected to an output end of the filter; a heat exchanger, an input end of which is connected to an output end of the high-pressure pump; a second buffer tank, an input end of which is connected to an output end of the heat exchanger, and an output end of which is connected to an ammonia fuel engine; wherein the working state of the pressure stabilizing module is controlled by the output power of the ship engine or the difference between the first pressure value and the second pressure value.

2. The system of claim 1, wherein, The system further comprises: a first temperature sensor arranged at the input end of the heater; a second temperature sensor arranged at the input end of the high-pressure pump; a third temperature sensor arranged at the output end of the high-pressure pump; a fourth temperature sensor arranged at the input end of the second buffer tank.

3. The system of claim 1, wherein, The system further comprises a first check valve; a first end of the first check valve is connected to the output end of the first low-pressure pump, and a second end of the first check valve is connected to the input end of the heater.

4. The system of claim 1, wherein, The system further comprises a second low-pressure pump and a second check valve; an input end of the second low-pressure pump is connected to a second output end of the liquid ammonia storage tank, an output end of the second low-pressure pump is connected to a first end of the second check valve, and a second end of the second check valve is connected to the input end of the heater.

5. The system of claim 4, wherein, The system further comprises a first regulating valve and a second regulating valve; the first regulating valve is arranged on a connecting pipeline between the first output end of the liquid ammonia storage tank and the input end of the first low-pressure pump; the second regulating valve is arranged on a connecting pipeline between the second output end of the liquid ammonia storage tank and the input end of the second low-pressure pump.

6. The system of claim 1, wherein, The system further comprises a third check valve; The first end of the third check valve is connected with the output end of the liquefier, and the second end of the third check valve is connected with the input end of the liquid ammonia storage tank.

7. The system of claim 1, wherein, The system further comprises a loop regulating valve, a fourth check valve and a pressure reducing valve; The first end of the loop regulating valve is connected with the input end of the heater, and the second end of the loop regulating valve is connected with the first end of the fourth check valve; The second end of the fourth check valve is connected with the first end of the pressure reducing valve; The second end of the pressure reducing valve is connected with the input end of the liquid ammonia storage tank.

8. The system of claim 1, wherein, The system further comprises a third pressure sensor and a fourth pressure sensor; The third pressure sensor is arranged at the input end of the high-pressure pump; The fourth pressure sensor is arranged at the input end of the second buffer tank.

9. A control method for a fuel supply system of the marine ammonia fuel engine according to any one of claims 1 to 8, characterized by, The method comprises the following steps: acquiring a current navigation working condition of a ship; acquiring a current output power of a ship engine according to the current navigation working condition of the ship; when it is determined that the current output power is in a first preset range or a second range, controlling the working state of a pressure stabilizing module to adjust the pressure of ammonia fuel input into the engine; when it is determined that the current output power is not in the first preset range or the second range, acquiring a first pressure value collected by a first pressure sensor and a second pressure value collected by a second pressure sensor; calculating the difference between the first pressure value and the second pressure value; when the difference is less than a pressure threshold value, controlling the working state of the pressure stabilizing module to adjust the pressure of ammonia fuel input into the engine.

10. The method of claim 9, wherein, The method further comprises the following steps: acquiring a first temperature value collected by a first temperature sensor; adjusting the preheating temperature of ammonia fuel by a heater according to the first temperature value; acquiring a second temperature value collected by a second temperature sensor; when the second temperature value is less than a first temperature threshold value, feeding back the preheating temperature of ammonia fuel by the heater again; when the second temperature value is greater than or equal to the first temperature threshold value, acquiring a third temperature value collected by a third temperature sensor; analyzing the influence state of a high-pressure pump on the temperature of ammonia fuel according to the second temperature value and the third temperature value; acquiring a fourth temperature value collected by a fourth temperature sensor; adjusting the heating process of liquid ammonia by a heat exchanger according to the fourth temperature value.

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