A dual-fuel power system, self-pressurized liquid ammonia supply device, and control method

Abstract

The present invention relates to a dual-fuel power system, a self-pressurized liquid ammonia supply device, and a control method. The self-pressurized liquid ammonia supply device of the dual-fuel power system includes a liquid ammonia storage tank, a liquid ammonia temperature sensor, a first heat exchanger, and an ammonia supply pipeline. The liquid ammonia temperature sensor and the first heat exchanger are installed in the liquid ammonia storage tank. The liquid ammonia temperature sensor is used to monitor the current liquid ammonia temperature value in the liquid ammonia storage tank; the first heat exchanger is used for heat exchange between coolant and liquid ammonia; the inlet end of the ammonia supply pipeline is connected to the bottom of the liquid ammonia storage tank and is equipped with a second solenoid valve for adjusting the liquid ammonia flow in the ammonia supply pipeline according to the current liquid ammonia temperature value. The self-pressurized liquid ammonia supply device uses heat exchange between coolant and liquid ammonia in its interior to increase the liquid ammonia temperature and vapor pressure, thereby achieving a stable liquid ammonia supply; the dual-fuel power system can also vaporize the injected liquid ammonia and control the temperature of the mixed gas by controlling the intake temperature, thereby improving the thermal efficiency of the entire machine.

Description

Technical Field

[0001] The present invention relates to the field of engines, and in particular to a dual-fuel power system, a self-pressurized liquid ammonia supply device, and a control method. Background Art

[0002] A dual-fuel powertrain primarily involves supplying diesel and ammonia to the engine in a specific manner for combustion. Typically, diesel, used as a pilot fuel, is injected into the cylinder through a fuel injector, while ammonia enters the cylinder through a separate intake system. During the intake process, ammonia and air mix to form a combustible mixture. Near the end of the intake compression stroke, diesel is injected into the cylinder and spontaneously ignites. This combustion ignites the ammonia, which reacts with oxygen, thus achieving dual-fuel combustion.

[0003] In existing dual-fuel power systems, liquid ammonia is heated and vaporized using engine coolant to form ammonia gas, which is then mixed with air and enters the intake manifold. However, this method has the problem of insufficient engine coolant vaporization capacity, liquefaction of the ammonia supply pipeline, resulting in unstable and insufficient ammonia supply, and the ammonia-air mixture entering the intake manifold, reducing the charging efficiency of the internal combustion engine. Although the use of liquid ammonia in-cylinder injection can effectively increase the amount of ammonia blended under high load, it has the problem of complex structure and difficult layout. Summary of the Invention

[0004] The present invention provides a dual-fuel power system, a self-pressurized liquid ammonia supply device, and a control method. The self-pressurized liquid ammonia supply device utilizes a thermal fluid to exchange heat with liquid ammonia inside the device to increase the liquid ammonia temperature and the gas pressure in the liquid ammonia storage tank, thereby improving the liquid ammonia supply stability and vaporization capacity. The dual-fuel power system is also provided with an intercooler air bypass device, which vaporizes and mixes the injected liquid ammonia through pressurized hot air, and utilizes the waste heat of the engine coolant and exhaust in stages, thereby improving the vaporization efficiency of the liquid ammonia.

[0005] The technical solutions provided by the present invention are as follows:

[0006] In a first aspect, the present invention provides a dual-fuel power system using NH3 as one of the fuels. The dual-fuel power system includes a self-pressurized liquid ammonia supply device, which includes:

[0007] Liquid ammonia storage tank, which is used to store liquid ammonia;

[0008] A liquid ammonia temperature sensor is installed in the liquid ammonia storage tank to monitor the current liquid ammonia temperature in the liquid ammonia storage tank;

[0009] A first heat exchanger is installed in the liquid ammonia storage tank and is used for heat exchange between the coolant and the liquid ammonia;

[0010] An ammonia supply pipeline, whose inlet end is connected to the bottom of the liquid ammonia storage tank, is used to output liquid ammonia; the ammonia supply pipeline is equipped with a second solenoid valve, which is used to adjust the liquid ammonia flow in the ammonia supply pipeline according to the current liquid ammonia temperature value in the liquid ammonia storage tank.

[0011] In combination with the first aspect of the present invention, in some embodiments, both ends of the first heat exchanger are connected to the engine coolant pipeline, and the engine coolant pipeline is configured with a first solenoid valve and a first temperature sensor. The first temperature sensor is used to monitor the current water temperature value of the engine coolant at the engine outlet, and the first solenoid valve is used to adjust the flow rate of the engine coolant flowing through the first heat exchanger according to the current water temperature value and the current liquid ammonia temperature value.

[0012] In combination with the first aspect of the present invention, in some embodiments, the dual-fuel power system further includes a gas-liquid mixer, which is provided with a liquid ammonia nozzle, a pressurized air inlet and a second temperature sensor; the liquid ammonia nozzle is connected to the outlet of the ammonia supply pipeline; the pressurized air inlet is used to supply pressurized air; the second temperature sensor is used to monitor the current air temperature value in the gas-liquid mixer; the outlet of the gas-liquid mixer is connected to the engine, so that the gas in the gas-liquid mixer enters the engine.

[0013] In conjunction with the first aspect of the present invention, in some embodiments, the dual-fuel power system is further configured with an intercooler air bypass device, the intercooler air bypass device comprising:

[0014] An air supply circuit, the air inlet end of which is used for the intake of pressurized air, and the air outlet end is connected to the pressurized air inlet; the air supply circuit includes a first air circuit and a second air circuit that are branched by a third solenoid valve; wherein, the first air circuit is equipped with an intercooler; the intercooler is used to cool the pressurized air flowing through the first air circuit, and the third solenoid valve is used to adjust the air flow ratio of the first air circuit and the second air circuit according to the current water temperature value and the current air temperature value.

[0015] In a second aspect, the present invention provides an intake control method for the dual-fuel power system, comprising:

[0016] Get the current liquid ammonia temperature in the liquid ammonia storage tank;

[0017] The liquid ammonia flow in the ammonia supply pipeline is adjusted according to the current liquid ammonia temperature value.

[0018] In conjunction with the second aspect of the present invention, in some embodiments, the intake control method for a dual-fuel power system further includes:

[0019] Get the current water temperature value in the engine coolant pipeline;

[0020] The flow rate of the engine coolant flowing through the first heat exchanger is adjusted according to the current water temperature value and the current liquid ammonia temperature value.

[0021] In conjunction with the second aspect of the present invention, in some embodiments, adjusting the flow rate of the engine coolant flowing through the first heat exchanger according to the current water temperature value and the current liquid ammonia temperature value includes:

[0022] When the current water temperature value is lower than the first preset water temperature value, the second solenoid valve is kept closed, and the first solenoid valve is adjusted so that the flow rate of the engine coolant flowing through the first heat exchanger is;

[0023] When the current water temperature is between the first preset water temperature and the second preset water temperature, regulating the engine coolant to flow entirely through the first heat exchanger;

[0024] When the current water temperature value is higher than the second preset water temperature value, the engine coolant is adjusted to flow through the first heat exchanger.

[0025] In conjunction with the second aspect of the present invention, in some embodiments, the intake control method for a dual-fuel power system further includes:

[0026] Get the current air temperature value in the gas-liquid mixer;

[0027] The air flow ratio between the first air path and the second air path is adjusted according to the current water temperature value and the current air temperature value.

[0028] In a third aspect, the present invention provides a self-pressurized liquid ammonia supply device, comprising:

[0029] Liquid ammonia storage tank, which is used to store liquid ammonia;

[0030] A liquid ammonia temperature sensor is installed in the liquid ammonia storage tank to monitor the current liquid ammonia temperature in the liquid ammonia storage tank;

[0031] a first heat exchanger, which is installed in the liquid ammonia storage tank and is used for heat exchange between the hot fluid and the liquid ammonia;

[0032] An ammonia supply pipeline, whose inlet end is connected to the bottom of the liquid ammonia storage tank, is used to output liquid ammonia; the ammonia supply pipeline is equipped with a second solenoid valve, which is used to adjust the liquid ammonia flow in the ammonia supply pipeline according to the current liquid ammonia temperature value in the liquid ammonia storage tank.

[0033] In a fourth aspect, the present invention provides a control method for the self-pressurized liquid ammonia supply device, comprising:

[0034] Get the current liquid ammonia temperature in the liquid ammonia storage tank;

[0035] The liquid ammonia flow in the ammonia supply pipeline is adjusted according to the current liquid ammonia temperature value.

[0036] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include:

[0037] 1. The dual-fuel power system provided by the embodiments of the present invention achieves self-supercharging by circulating cooling water to heat liquid ammonia. Simultaneously, waste heat from the compressor outlet air is used to heat the vaporized and injected liquid ammonia, improving the vaporization efficiency of the liquid ammonia. Furthermore, the high latent heat of vaporization of liquid ammonia can lower the engine intake temperature, thereby achieving intake temperature control.

[0038] 2. The self-pressurized liquid ammonia supply device provided in an embodiment of the present invention utilizes heat exchange between a hot fluid and liquid ammonia to increase the temperature of the liquid ammonia and the gas pressure in the liquid ammonia storage tank, thereby enabling stable output of liquid ammonia. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 A schematic diagram of the dual-fuel power system provided by the present invention;

[0041] Figure 2 A flow chart of an intake control method for a dual-fuel power system provided by the present invention;

[0042] Figure 3 A schematic diagram of a self-pressurized liquid ammonia supply device provided in an embodiment of the present invention;

[0043] In the picture:

[0044] 1. Liquid ammonia storage tank;

[0045] 2. Liquid ammonia temperature sensor;

[0046] 3. First heat exchanger;

[0047] 4. Engine coolant pipe; 41. First solenoid valve; 42. First temperature sensor; 43. Second heat exchanger;

[0048] 5. Ammonia supply pipeline; 51. Second solenoid valve;

[0049] 6. Gas-liquid mixer; 61. Liquid ammonia nozzle; 62. Pressurized air inlet; 63. Second temperature sensor;

[0050] 7. Turbine compressor; 71. Turbine; 72. Compressor;

[0051] 8. Air supply line; 81. First air line; 82. Second air line; 83. Intercooler; 84. Third solenoid valve;

[0052] 9. Fuel tank; 91. Fuel pump;

[0053] 10. Engine. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0055] Embodiments of the present invention provide a dual-fuel power system, a self-pressurized liquid ammonia supply device, and a control method. This self-pressurized liquid ammonia supply device can stably provide liquid ammonia with high vaporization capacity, resolving the issues of low gas supply efficiency when NH3 fuel is provided in the form of ammonia gas, as well as low vaporization efficiency when provided in the form of liquid ammonia. In addition to the aforementioned advantages, a dual-fuel power system utilizing this self-pressurized liquid ammonia supply device also achieves precise control of the engine 10 intake mixture temperature through an intercooler air bypass device.

[0056] like Figure 1 As shown, the dual-fuel power system provided by the present invention uses NH3 as one of the fuels. The dual-fuel power system includes a self-pressurized liquid ammonia supply device, which includes:

[0057] Liquid ammonia storage tank 1, which is used to store liquid ammonia;

[0058] a liquid ammonia temperature sensor 2, which is installed in the liquid ammonia storage tank 1 and is used to monitor the current liquid ammonia temperature value in the liquid ammonia storage tank 1;

[0059] A first heat exchanger 3 is installed in the liquid ammonia storage tank 1 and is used for heat exchange between the engine coolant and the liquid ammonia;

[0060] The ammonia supply pipeline 5 has its inlet end connected to the bottom of the liquid ammonia storage tank 1 for outputting liquid ammonia; the ammonia supply pipeline 5 is equipped with a second solenoid valve 51, which is used to adjust the liquid ammonia flow in the ammonia supply pipeline 5 according to the current liquid ammonia temperature value in the liquid ammonia storage tank 1.

[0061] The dual-fuel power system provided by the present invention uses NH3 as the first fuel, and the second fuel is selected from one of diesel, gasoline, hydrogen, and natural gas. NH3 can be used as the main fuel or auxiliary fuel. Preferably, diesel is used as the ignition fuel and NH3 is used as the main fuel. During the storage stage, NH3 is stored in the liquid ammonia storage tank 1 in the form of liquid ammonia, and the second fuel is stored in the fuel tank 9; during the combustion stage, NH3 enters the engine 10 in the form of ammonia gas, and the second fuel is pumped into the engine 10 through the fuel pump 91. In order to efficiently convert liquid ammonia into ammonia gas, the present invention sets a first heat exchanger 3 in the liquid ammonia storage tank 1, and uses the heat of the engine coolant to heat the liquid ammonia to increase the temperature of the liquid ammonia and the gas pressure in the liquid ammonia storage tank 1, so that the liquid ammonia has a higher outward injection speed and absorbs a small amount of heat in the mixer to vaporize.

[0062] In some embodiments of the present invention, the coolant is one or more of engine coolant, battery pack coolant, and air conditioning system coolant, preferably engine coolant. Figure 1 As shown, the dual-fuel power system of the present invention is equipped with an engine coolant pipeline 4. The engine coolant pipeline 4 comprises two parallel pipelines: one pipeline passes through the first heat exchanger 3 and enters the engine 10, and the other pipeline passes through the second heat exchanger 43 and enters the engine 10 directly. A first temperature sensor 42 is provided at the engine coolant outlet next to the engine 10 to monitor the current water temperature of the engine coolant at the engine 10 outlet. The first heat exchanger 3 is connected to the engine coolant pipeline 4 at both ends. The engine coolant pipeline 4 is equipped with a first solenoid valve 41. The first solenoid valve 41 is used to adjust the flow rate of the engine coolant flowing through the first heat exchanger 3 based on the current water temperature of the engine coolant pipeline 4 and the temperature of the liquid ammonia in the liquid ammonia storage tank 1.

[0063] The present invention utilizes a first temperature sensor 42 to monitor the current water temperature within the engine coolant pipe 4. When the water temperature is below a first preset water temperature, it indicates that the engine 10 is currently too low to be suitable for NH3 fuel combustion. At this point, the second solenoid valve 51 is kept closed, preventing liquid ammonia output. The first solenoid valve 41 is adjusted to reduce the flow rate of engine coolant through the first heat exchanger 3 to zero, allowing it to flow directly through the second heat exchanger 43 and into the engine 10. If the engine coolant were to flow through the first heat exchanger 3 at this point, the liquid ammonia would heat up slowly. Furthermore, the liquid ammonia within the liquid ammonia storage tank 1 would rise in temperature and vapor pressure, yet be unable to be output. This would increase the internal pressure of the liquid ammonia storage tank 1 and create a risk of tank explosion.

[0064] When the current water temperature is between the first preset water temperature and the second preset water temperature, the engine coolant is regulated to flow entirely through the first heat exchanger 3 to heat the liquid ammonia. Simultaneously, the current liquid ammonia temperature in the liquid ammonia storage tank 1 is obtained. When the current liquid ammonia temperature is lower than the first preset liquid ammonia temperature, the second solenoid valve 51 remains closed, and the engine 10 maintains a single-fuel combustion mode using the second fuel. When the current liquid ammonia temperature is not lower than the first preset liquid ammonia temperature, the second solenoid valve 51 is opened to discharge liquid ammonia, and the engine 10 enters a dual-fuel combustion mode using NH3 fuel and the second fuel. At this time, the second solenoid valve 51 is regulated based on the current liquid ammonia temperature to adjust the liquid ammonia flow rate in the ammonia supply pipeline 5 so that the changed liquid ammonia temperature falls within the preset liquid ammonia temperature range. The first solenoid valve 41 is regulated based on the current liquid ammonia temperature in the liquid ammonia storage tank 1 to adjust the engine coolant flow rate through the first heat exchanger 3 so that the changed liquid ammonia temperature falls within the preset liquid ammonia temperature range, thereby ensuring the safety of the liquid ammonia storage tank 1 and the stability of the liquid ammonia supply pressure. Specifically, when the liquid ammonia temperature sensor 2 detects that the current liquid ammonia temperature in the liquid ammonia storage tank 1 is higher than the upper limit of the preset liquid ammonia temperature range, the first solenoid valve 41 is adjusted to reduce the flow rate of the engine coolant through the first heat exchanger 3, reducing the heat exchange between the liquid ammonia and the engine coolant, thereby stabilizing the liquid ammonia temperature in the liquid ammonia storage tank 1. When the liquid ammonia temperature sensor 2 detects that the current liquid ammonia temperature in the liquid ammonia storage tank 1 is lower than the first preset liquid ammonia temperature value, the first solenoid valve 41 is adjusted to increase the flow rate of the engine coolant through the first heat exchanger 3, thereby increasing the heat exchange between the liquid ammonia and the engine coolant, and keeping the liquid ammonia temperature in the liquid ammonia storage tank 1 within the preset liquid ammonia temperature range. This configuration stabilizes the liquid ammonia temperature in the liquid ammonia storage tank 1 within the preset liquid ammonia temperature range, thereby stabilizing the liquid phase state and outward injection velocity of the liquid ammonia.

[0065] In some embodiments of the present invention, the dual-fuel power system also includes a gas-liquid mixer 6, which is provided with a liquid ammonia nozzle 61, a pressurized air inlet 62 and a second temperature sensor 63; the liquid ammonia nozzle 61 is connected to the outlet of the ammonia supply pipeline 5; the pressurized air inlet 62 is used to inject pressurized air; the second temperature sensor 63 is used to monitor the current air temperature value in the gas-liquid mixer 6; the outlet of the gas-liquid mixer 6 is connected to the engine 10, so that the gas in the gas-liquid mixer 6 enters the engine 10.

[0066] The dual-fuel power system of the present invention does not directly spray liquid nitrogen into engine 10. Instead, it mixes liquid nitrogen with pressurized air in a gas-liquid mixer 6 to form a mixed gas, which is then fed into engine 10. The gas-liquid mixer 6 of the present invention is equipped with a liquid ammonia nozzle 61 connected to the outlet of the ammonia supply pipeline 5 for injecting and vaporizing liquid ammonia. A pressurized air inlet 62 is also provided for injecting pressurized air. After being pressurized by the turbo compressor 7, the pressurized air heats up. Upon encountering the liquid ammonia in the gas-liquid mixer 6, heat exchange occurs. The highly vaporizable liquid ammonia rapidly vaporizes into ammonia gas, simultaneously cooling the pressurized air. Both enter the engine 10 as a mixture of air and ammonia.

[0067] In some embodiments of the present invention, the dual-fuel power system is further provided with an intercooler air bypass device, which includes: an air supply path 8, an air inlet end of which is used for the entry of pressurized air, and an air outlet end connected to the pressurized air inlet 62; the air supply path 8 includes a first air path 81 and a second air path 82 which are branched by a third solenoid valve 84; wherein, the first air path 81 is provided with an intercooler 83; the intercooler 83 is used to cool the pressurized air flowing through the first air path 81, and the third solenoid valve 84 is used to adjust the air flow ratio of the first air path 81 and the second air path 82 according to the current water temperature value and the current air temperature value.

[0068] The purpose of the intercooler air bypass device in the present invention is to regulate the temperature of the charge air entering the gas-liquid mixer 6. When the current water temperature is lower than a first preset water temperature, indicating that the engine 10 is at a low temperature, the second solenoid valve 51 is closed, preventing the ammonia supply pipeline 5 from delivering liquid ammonia to the gas-liquid mixer 6. The third solenoid valve 84 is controlled to prevent the high-temperature charge air from flowing through the intercooler 83 and directly into the gas-liquid mixer 6 via the uncooled second air path 82, where it then enters the engine 10 for warm-up. During this process, the charge air temperature does not decrease, allowing the engine 10 to quickly heat up and improve the combustion efficiency of the second fuel. When the current water temperature in the engine coolant pipeline 4 is no lower than the first preset water temperature, the third solenoid valve 84 is adjusted based on the current air temperature to adjust the ratio of charge air flowing through the first air path 81 and the second air path 82. After being cooled by the intercooler 83, the charge air in the first air path 81 is mixed with the uncooled charge air in the second air path 82 in the gas-liquid mixer 6 to produce a mixed gas at a suitable temperature.

[0069] In addition, the third solenoid valve 84 is further used to adjust the air flow ratio between the first air path 81 and the second air path 82 according to the current engine load requirement and the current temperature value.

[0070] In some embodiments of the present invention, the air inlet of air supply path 8 is connected to a turbo compressor 7, which includes a turbine 71 and a compressor 72, for providing pressurized air. Exhaust gas acts on turbine 71, driving compressor 72 to operate, thereby supercharging the air. The supercharged air temperature increases. The high-temperature supercharged air flowing through first air path 81 is cooled by intercooler 83, then enters the gas-liquid mixer 6 together with the high-temperature supercharged air flowing through second air path 82.

[0071] like Figure 2 As shown, the intake control method for the dual-fuel power system provided by the present invention includes:

[0072] Get the current liquid ammonia temperature value in liquid ammonia storage tank 1;

[0073] The liquid ammonia flow rate in the ammonia supply pipeline 5 is adjusted according to the current liquid ammonia temperature value.

[0074] The current liquid ammonia temperature is proportional to the vapor pressure in the liquid ammonia storage tank 1. The higher the current liquid ammonia temperature, the greater the vaporization capacity and injection velocity of the liquid ammonia. This intake control method regulates the liquid ammonia flow rate in the ammonia supply pipeline 5 based on the current liquid ammonia temperature, thereby ensuring a stable injection velocity and liquid phase of the liquid ammonia output from the liquid ammonia storage tank 1. Specifically, when the current liquid ammonia temperature is lower than a first preset liquid ammonia temperature, the vapor pressure within the liquid ammonia storage tank 1 is low, and the liquid ammonia vaporization capacity is low. The liquid ammonia flows out of the liquid ammonia storage tank 1 almost solely by gravity, without any pressurization. At this point, the second solenoid valve 51 should be closed. Once the liquid ammonia temperature is no lower than the first preset liquid ammonia temperature, the liquid ammonia in the liquid ammonia storage tank 1 has a high vaporization capacity and injection velocity. The second solenoid valve 51 should then be opened to allow the liquid ammonia to be ejected, mixed with air, and vaporized through heat exchange.

[0075] In some embodiments of the present invention, the control method for a dual-fuel power system further includes: obtaining the current water temperature value within the engine coolant pipeline 4; and adjusting the flow rate of the engine coolant flowing through the first heat exchanger 3 based on the current water temperature value and the current liquid ammonia temperature value. The temperature of the engine coolant affects the heating efficiency of the liquid ammonia, as well as the temperature and vapor pressure within the liquid ammonia storage tank 1. By detecting the current water temperature value of the engine coolant and adjusting the flow rate of the engine coolant flowing through the first heat exchanger 3, the present invention can adjust the heating efficiency of the liquid ammonia, thereby preventing the temperature and vapor pressure within the liquid ammonia storage tank 1 from being too low, which could affect the injection velocity of the liquid ammonia and the risk of phase change during transportation. It can also prevent the temperature and vapor pressure within the liquid ammonia storage tank 1 from being too high, which could cause a pipe burst hazard.

[0076] In some embodiments of the present invention, the flow rate of the engine coolant flowing through the first heat exchanger 3 is adjusted according to the current water temperature value and the current liquid ammonia temperature value, including: when the current water temperature value is lower than the first preset water temperature value, keeping the second solenoid valve 51 closed, and adjusting the first solenoid valve 41 so that the flow rate of the engine coolant flowing through the first heat exchanger 3 is 0; when the current water temperature value is between the first preset water temperature value and the second preset water temperature value, adjusting the entire engine coolant to flow through the first heat exchanger 3; when the current water temperature value is higher than the second preset water temperature value, adjusting the engine coolant to partially flow through the first heat exchanger 3.

[0077] When the current water temperature is lower than the first preset water temperature, it means that the temperature of the engine 10 is too low and is not suitable for NH3 fuel combustion. At this time, the second solenoid valve 51 is closed, liquid ammonia is not supplied, and the engine enters the single-fuel combustion mode of the second fuel; and the first solenoid valve 41 is closed so that the engine coolant does not pass through the first heat exchanger 3, to avoid the liquid ammonia temperature being too high when the first solenoid valve 41 is not opened, and the steam pressure in the liquid ammonia storage tank 1 is too high, causing the tank to explode. When the current water temperature is between the first preset water temperature and the second preset water temperature, the engine coolant is adjusted to flow through the first heat exchanger 3 to quickly heat the liquid ammonia; when the current liquid ammonia temperature is higher than the first preset liquid ammonia temperature, the second solenoid valve 51 is kept open, liquid ammonia is started to be output, and the engine 10 enters the dual-fuel combustion mode; when the current water temperature is higher than the second preset water temperature, the current liquid ammonia temperature is not lower than the first preset liquid ammonia temperature, and at this time, a portion of the engine coolant is allowed to flow through the first heat exchanger 3. The intake control method can control the intake of ammonia at different temperature stages of the engine 10, thereby ensuring that the engine has a higher combustion efficiency.

[0078] In some embodiments of the present invention, the air intake control method further includes: obtaining a current air temperature value in the gas-liquid mixer 6; and adjusting the air flow ratio of the first air path 81 and the second air path 82 according to the current water temperature value and the current air temperature value.

[0079] In some embodiments of the present invention, the air flow ratio of the first air path 81 and the second air path 82 is adjusted according to the current water temperature value and the current air temperature value, including: when the current water temperature value is lower than the first preset water temperature value, the flow rate of the pressurized air flowing through the first air path 81 is 0; when the current water temperature value is between the first preset water temperature value and the second preset water temperature value, the air temperature value in the gas-liquid mixer 6 is obtained; according to the current air temperature value, the air flow ratio of the first air path 81 and the second air path 82 is adjusted to control the changed air temperature within the preset air temperature range; when the current water temperature value is higher than the second preset water temperature value, the flow rate of the pressurized air flowing through the first air path 81 is 0. When the current water temperature is lower than the first preset water temperature, the engine 10 needs to be quickly warmed up. At this time, the cooling of the supercharged air should be omitted, so that the supercharged air can directly enter the engine 10 for warming up. When the current water temperature is between the first preset water temperature and the second preset water temperature, the second solenoid valve 51 is opened to output liquid ammonia. At this time, the uncooled supercharged air should be heat-exchanged with the liquid ammonia to quickly vaporize the liquid ammonia, while reducing the temperature of the supercharged air, thereby reducing the power consumption of the intercooler 83. When the current water temperature is higher than the second preset water temperature, it means that the engine 10 is under a high load condition. At this time, the amount of circulating fuel injection in the cylinder and the amount of ammonia required for combustion increase. The present invention adjusts the supercharged air to flow through the second air path 82 according to the current water temperature, and increases the opening of the second solenoid valve 51 to increase the supply of ammonia and the ammonia mixing ratio, thereby ensuring that the engine 10 has a larger power output. At the same time, the liquid ammonia cools the supercharged air, reducing the risk of engine explosion pressure, thereby achieving NO x Ultra-low emissions.

[0080] The intake control method also includes obtaining the current engine load requirement and adjusting the air flow ratio between the first air path 81 and the second air path 82 based on the current engine load requirement and the current temperature. The ECU collects the engine throttle signal to obtain the current engine load requirement. When the engine 10 enters dual-fuel combustion mode, the air flow ratio between the first air path 81 and the second air path 82 is adjusted by controlling the third solenoid valve 84. This allows for precise vaporization of the liquid ammonia and temperature control of the mixed gas, while simultaneously reducing the power consumption of the intercooler fan in the intercooler 83.

[0081] like Figure 3 As shown, the self-pressurized liquid ammonia supply device provided by the present invention includes:

[0082] Liquid ammonia storage tank 1, which is used to store liquid ammonia;

[0083] a liquid ammonia temperature sensor 2, which is installed in the liquid ammonia storage tank 1 and is used to monitor the current liquid ammonia temperature value in the liquid ammonia storage tank 1;

[0084] a first heat exchanger 3 , which is installed in the liquid ammonia storage tank 1 and allows the hot fluid to pass through the first heat exchanger 3 to exchange heat with the liquid ammonia;

[0085] The ammonia supply pipeline 5 has its inlet end connected to the bottom of the liquid ammonia storage tank 1 for outputting liquid ammonia; the ammonia supply pipeline 5 is equipped with a second solenoid valve 51, which is used to adjust the liquid ammonia flow in the ammonia supply pipeline 5 according to the current liquid ammonia temperature value in the liquid ammonia storage tank 1.

[0086] The self-pressurized liquid ammonia supply device includes a first heat exchanger 3 within the liquid ammonia storage tank 1. The hot fluid and liquid ammonia exchange heat in the first heat exchanger 3, thereby increasing the temperature and vapor pressure of the liquid ammonia within the liquid ammonia storage tank 1, thereby improving the vaporization efficiency of the liquid ammonia outside the liquid ammonia storage tank 1. Furthermore, the self-pressurized liquid ammonia supply device includes a second solenoid valve 51 that regulates the flow of liquid ammonia in the ammonia supply pipeline 5 based on the liquid ammonia temperature within the liquid ammonia storage tank 1. This prevents the liquid ammonia temperature within the liquid ammonia storage tank 1 from being too high, potentially leading to an explosion, and also prevents the liquid ammonia temperature from being too low due to rapid outflow. Layout-wise, the self-pressurized liquid ammonia supply device integrates the liquid ammonia temperature sensor 2 and the first heat exchanger 3 within the liquid ammonia storage tank 1, resulting in a simple structure and compact size. It can be generated separately and then installed in a dual-fuel power system using NH3 as one fuel, providing liquid ammonia with high vaporization efficiency.

[0087] The control method of the self-pressurized liquid ammonia supply device provided by the present invention includes:

[0088] Get the current liquid ammonia temperature value in liquid ammonia storage tank 1;

[0089] The liquid ammonia flow rate in the ammonia supply pipeline 5 is adjusted according to the current liquid ammonia temperature value.

[0090] Adjusting the liquid ammonia flow rate in the ammonia supply pipeline 5 according to the current liquid ammonia temperature value includes:

[0091] When the current liquid ammonia temperature value is lower than the first preset liquid ammonia temperature value, the second solenoid valve 51 is closed;

[0092] When the current liquid ammonia temperature value is not lower than the first preset liquid ammonia temperature value, the second solenoid valve 51 is opened, and the liquid ammonia flow in the ammonia supply pipeline 5 is adjusted according to the current liquid ammonia temperature value, so that the changed liquid ammonia temperature value is within the preset liquid ammonia temperature range.

[0093] In the control method of the self-pressurized liquid ammonia supply device, when the current liquid ammonia temperature value is lower than the first preset liquid ammonia temperature value, the vaporization capacity of the liquid ammonia in the liquid ammonia storage tank 1 is low, and it flows out of the liquid ammonia storage tank 1 only by its own gravity without any pressurization effect. At this time, the second solenoid valve 51 should be closed. When the current liquid ammonia temperature value is not lower than the first preset liquid ammonia temperature value, the liquid ammonia in the liquid ammonia storage tank 1 has a high spraying capacity, and the second solenoid valve 51 is opened to spray the liquid ammonia.

[0094] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0095] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0096] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A dual-fuel power system using NH3 as one of the fuels, characterized by: The dual-fuel power system includes a self-pressurized liquid ammonia supply device, which includes: A liquid ammonia storage tank (1), which is used to store liquid ammonia; a liquid ammonia temperature sensor (2), installed in the liquid ammonia storage tank (1) and used to monitor the current liquid ammonia temperature value in the liquid ammonia storage tank (1); a first heat exchanger (3) installed in the liquid ammonia storage tank (1) for heat exchange between the coolant and the liquid ammonia; both ends of the first heat exchanger (3) are connected to an engine coolant pipe (4); the engine coolant pipe (4) is provided with a first solenoid valve (41) and a first temperature sensor (42); the first temperature sensor (42) is used to monitor the current water temperature of the engine coolant at the outlet of the engine (10); an ammonia supply pipeline (5), the inlet end of which is connected to the bottom of the liquid ammonia storage tank (1) and is used to output liquid ammonia; the ammonia supply pipeline (5) is provided with a second solenoid valve (51), and the second solenoid valve (51) is used to adjust the liquid ammonia flow rate in the ammonia supply pipeline (5) according to the current liquid ammonia temperature value in the liquid ammonia storage tank (1); A gas-liquid mixer (6), the gas-liquid mixer (6) being provided with a liquid ammonia nozzle (61), a pressurized air inlet (62) and a second temperature sensor (63); the liquid ammonia nozzle (61) being connected to the outlet of the ammonia supply pipeline (5); the pressurized air inlet (62) being used to supply pressurized air; the second temperature sensor (63) being used to monitor the current air temperature value in the gas-liquid mixer (6); An intercooler air bypass device, the intercooler air bypass device comprising: an air supply path (8), an air inlet end of which is used for the inlet of pressurized air, and an air outlet end connected to the pressurized air inlet (62); the air supply path (8) comprises a first air path (81) and a second air path (82) which are branched by a third solenoid valve (84); wherein the first air path (81) is provided with an intercooler (83); the intercooler (83) is used to cool the pressurized air flowing through the first air path (81), and the third solenoid valve (84) is used to adjust the air flow ratio of the first air path (81) and the second air path (82) according to a current water temperature value and a current air temperature value.

2. The dual-fuel power system according to claim 1, characterized in that: The first solenoid valve (41) is used to adjust the flow rate of the engine coolant flowing through the first heat exchanger (3) according to the current water temperature value and the current liquid ammonia temperature value.

3. The dual-fuel power system according to claim 2, characterized in that: The outlet of the gas-liquid mixer (6) is in communication with the engine (10), so that the gas in the gas-liquid mixer (6) can enter the engine (10).

4. An intake control method for a dual-fuel power system according to any one of claims 1 to 3, characterized in that: include: Obtain the current liquid ammonia temperature value in the liquid ammonia storage tank (1); The liquid ammonia flow rate in the ammonia supply pipeline (5) is adjusted according to the current liquid ammonia temperature value.

5. The control method of the dual-fuel power system according to claim 4, characterized in that: The air intake control method for the dual fuel power system further includes: Obtain the current water temperature value in the engine coolant pipe (4); The flow rate of the engine coolant flowing through the first heat exchanger (3) is adjusted according to the current water temperature value and the current liquid ammonia temperature value.

6. The control method of the dual-fuel power system according to claim 5, characterized in that: Adjusting the flow rate of the engine coolant flowing through the first heat exchanger (3) according to the current water temperature value and the current liquid ammonia temperature value includes: When the current water temperature value is lower than the first preset water temperature value, the second solenoid valve (51) is kept closed, and the first solenoid valve (41) is adjusted so that the flow rate of the engine coolant flowing through the first heat exchanger (3) is 0; When the current water temperature is between the first preset water temperature and the second preset water temperature, regulating the entire engine coolant to flow through the first heat exchanger (3); When the current water temperature value is higher than the second preset water temperature value, the engine coolant is regulated to partially flow through the first heat exchanger (3).

7. The control method of the dual-fuel power system according to claim 5, characterized in that: The air intake control method for the dual fuel power system further includes: Obtain the current air temperature value in the gas-liquid mixer (6); The air flow ratio of the first air path (81) and the second air path (82) is adjusted according to the current water temperature value and the current air temperature value.

8. A self-pressurizing liquid ammonia supply device for a dual-fuel power system according to any one of claims 1 to 3, characterized in that: include: A liquid ammonia storage tank (1), which is used to store liquid ammonia; a liquid ammonia temperature sensor (2), installed in the liquid ammonia storage tank (1) and used to monitor the current liquid ammonia temperature value in the liquid ammonia storage tank (1); A first heat exchanger (3), which is installed in the liquid ammonia storage tank (1) and is used for heat exchange between the hot fluid and the liquid ammonia; An ammonia supply pipeline (5) has an inlet end connected to the bottom of the liquid ammonia storage tank (1) for outputting liquid ammonia; the ammonia supply pipeline (5) is provided with a second solenoid valve (51), and the second solenoid valve (51) is used to adjust the liquid ammonia flow in the ammonia supply pipeline (5) according to the current liquid ammonia temperature value in the liquid ammonia storage tank (1).

9. A control method for the self-pressurized liquid ammonia supply device according to claim 8, characterized in that: include: Obtain the current liquid ammonia temperature value in the liquid ammonia storage tank (1); The liquid ammonia flow rate in the ammonia supply pipeline (5) is adjusted according to the current liquid ammonia temperature value.

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