Ammonia fuel supply system for ammonia internal combustion engine

Abstract

The ammonia fuel supply system comprises a liquid ammonia supply assembly, an ammonia injection assembly and a pumping assembly, the pumping assembly comprises a liquid ammonia pump, the liquid ammonia pump is provided with a liquid ammonia pressurization cavity and a cooling expansion cavity which have a dividing wall heat exchange relation, and the liquid ammonia pressurization cavity is provided with a liquid ammonia inlet and a liquid ammonia outlet; the liquid ammonia inlet is connected with the liquid ammonia supply assembly, the liquid ammonia outlet is connected with the ammonia injection assembly, the cooling expansion cavity is provided with an expansion inlet and an expansion outlet, and an expansion valve is connected between the expansion inlet and the liquid ammonia supply assembly. Part of liquid ammonia is adopted as a refrigerant, normal-temperature ammonia can be filled, the liquid ammonia tank does not need heat insulation, liquid ammonia in the tank flows out automatically, a single-stage pump scheme can be adopted, the liquid supply amount can be accurately adjusted, oil return is not needed, and the system is simple, low in cost and high in efficiency.

Description

Technical Field

[0001] The invention relates to the field of liquid ammonia supply for an ammonia internal combustion engine, and in particular to an ammonia fuel supply system for an ammonia internal combustion engine. Background Art

[0002] Ammonia internal combustion engines are still in the research stage, especially the direct injection liquid ammonia supply system. In some known research and application examples, a two-stage pressurization scheme is usually adopted to achieve the pumping of low-temperature liquid ammonia, that is, the ammonia liquid in the ammonia tank is pressurized by the first-stage ammonia pump and then transported to the second-stage ammonia pump, which is pressurized again by the second-stage ammonia pump and supplied to the engine for use. A buffer device is also required between the first-stage pump and the second-stage pump, and ammonia liquid is required to flow back after the second-stage pump. In addition, due to the high operating temperature of the ammonia pump, only low-temperature ammonia can be transported to avoid liquid ammonia vaporization. It can be seen that the existing liquid ammonia supply system has the following problems: there is a risk of gas binding, only low-temperature ammonia can be transported, the overall volume is large, and the cost is high. In addition, if the workload of the ammonia internal combustion engine changes greatly, the load changes frequently, and the liquid supply pressure needs to be adjusted according to the working conditions, the pressure response is poor and it is difficult to achieve accurate pumping. Summary of the invention The object of the present invention is to provide an ammonia fuel supply system for an ammonia internal combustion engine, which is suitable for the storage and transportation of liquid ammonia at room temperature, can effectively avoid gas binding, and achieve precise pumping, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial choice or create conditions.

[0003] The technical solutions adopted to solve the above technical problems are: The present invention provides an ammonia fuel supply system for an ammonia internal combustion engine, comprising: A liquid ammonia supply component, used for supplying liquid ammonia; an ammonia injection assembly connected to the ammonia internal combustion engine; A pumping assembly comprises a liquid ammonia pump, wherein the liquid ammonia pump is provided with a liquid ammonia boosting chamber and a cooling expansion chamber having a partition heat exchange relationship, the liquid ammonia boosting chamber has a liquid ammonia inlet and a liquid ammonia outlet, the liquid ammonia inlet is connected to the liquid ammonia supply assembly, the liquid ammonia outlet is connected to the ammonia injection assembly, the cooling expansion chamber has an expansion inlet and an expansion outlet, and an expansion valve is connected between the expansion inlet and the liquid ammonia supply assembly.

[0004] The beneficial effects of the present invention are: When in use, the liquid ammonia supply component supplies liquid ammonia to the liquid ammonia pump. The liquid ammonia is divided into two paths in the liquid ammonia pump. One path enters from the liquid ammonia inlet, is pressurized through the liquid ammonia boosting chamber to form high-pressure liquid ammonia, and then is pumped out from the liquid ammonia outlet to the ammonia injection component, and is sprayed by the ammonia injection component to supply ammonia for combustion consumption by the internal combustion engine. The other path is vaporized and absorbs heat in the cooling expansion chamber through the expansion valve. The heat is exchanged through the partition wall between the liquid ammonia boosting chamber and the cooling expansion chamber, which reduces the temperature of the liquid ammonia boosting chamber, ensures that the liquid ammonia is not vaporized, and ensures that the pump works normally to generate pressure. The liquid ammonia pump is accurately pumped to the internal combustion engine for use according to demand without reflux. The present invention adopts a part of liquid ammonia as a refrigerant, and realizes the cooling of the liquid ammonia pump by virtue of the large latent heat of ammonia vaporization. It is suitable for the storage and transportation of liquid ammonia at room temperature, can effectively avoid gas binding, and realizes precise pumping.

[0005] As a further improvement of the above technical solution, the ammonia fuel supply system also includes an air intake assembly connected to the ammonia internal combustion engine, and the expansion outlet is connected to the air intake assembly.

[0006] As a further improvement of the above technical solution, the air intake assembly includes an air intake pipe, a compressor and a throttle valve sequentially arranged in the air intake pipe, and the air intake pipe is provided with at least one first ammonia access point connected to the expansion outlet.

[0007] As a further improvement of the above technical solution, the ammonia fuel supply system also includes an exhaust assembly connected to the ammonia internal combustion engine, and the expansion outlet is connected to the exhaust assembly.

[0008] As a further improvement of the above technical solution, the exhaust assembly includes an exhaust pipe and an exhaust gas processor arranged on the exhaust pipe, and the exhaust gas processor is provided with a second ammonia access point connected to the expansion outlet.

[0009] As a further improvement of the above technical solution, the liquid ammonia pump includes a pump head and a piston body, the pump head is provided with a piston cavity, the piston body is slidably arranged in the piston cavity to form the liquid ammonia boosting cavity, and the cooling expansion cavity is formed on the pump head.

[0010] As a further improvement of the above technical solution, the liquid ammonia outlet is provided with a one-way valve and a pressure relief valve arranged in parallel, and the liquid ammonia inlet is provided with a liquid inlet solenoid valve. The flow direction of the one-way valve is from the liquid ammonia boosting chamber to the ammonia injection assembly. The one-way valve is configured to open when the pressure on the inlet side of the one-way valve is greater than a first preset value so that the liquid ammonia outlet is connected to the ammonia injection assembly. The pressure relief valve is configured to open when the pressure on the outlet side of the one-way valve is greater than a second preset value so that the ammonia injection assembly is connected to the liquid ammonia boosting chamber and communicates with the liquid ammonia inlet when the liquid inlet solenoid valve is opened.

[0011] As a further improvement of the above technical solution, the liquid ammonia supply assembly includes a liquid ammonia tank, the liquid ammonia tank is provided with a liquid outlet and a pressurizing port, and the liquid outlet is connected to the liquid ammonia inlet.

[0012] As a further improvement of the above technical solution, the liquid outlet is connected to an ammonia filter.

[0013] As a further improvement of the above technical solution, the liquid ammonia inlet is connected to a vent port, and the vent port is provided with a vent valve.

[0014] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments; Figure 1 This is a structural schematic diagram of an embodiment of the ammonia fuel supply system provided by the present invention; Figure 2 This is a partial schematic diagram of an embodiment of the liquid ammonia pump provided by the present invention; Figure Number: Liquid ammonia supply assembly 100; liquid ammonia tank 110; liquid outlet 111; pressurizing port 112; ammonia filter 120; Ammonia injection assembly 200; Ammonia internal combustion engine 300; Liquid ammonia pump 400; liquid ammonia booster chamber 410; liquid ammonia inlet 411; liquid inlet solenoid valve 4111; liquid ammonia outlet 412; cooling expansion chamber 420; expansion inlet 421; expansion outlet 422; expansion valve 430; pump head 440; piston chamber 441; piston body 450; one-way valve 460; pressure relief valve 470; Intake assembly 500; intake pipe 510; first ammonia access point 511; compressor 520; throttle valve 530; Exhaust assembly 600; exhaust pipe 610; turbocharger 611; Tail gas processor 620; second ammonia access point 621; Ammonia internal combustion engine 300. DETAILED DESCRIPTION

[0016] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0017] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0018] In the description of the present invention, if there are words such as "several", it means one or more, "more" means more than two, greater than, less than, exceed, etc. are understood as not including the number, and above, below, within, etc. are understood as including the number.

[0019] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0020] The ammonia internal combustion engine 300 is still in the research stage, especially the direct injection liquid ammonia supply system in the cylinder. In some known research and application examples, a two-stage pressurization scheme is usually adopted, that is, the ammonia liquid in the ammonia tank is pressurized by the primary ammonia pump and then transported to the secondary ammonia pump, which is then pressurized again by the secondary ammonia pump and supplied to the engine for use. A buffer device may need to be added between the primary pump and the secondary pump, and the ammonia liquid may need to be refluxed after the secondary pump. Only low-temperature ammonia can be transported. In order to ensure the low temperature of ammonia, it is also necessary to use an insulated storage tank, a buffer tank, etc. to prevent the temperature of the stored ammonia from rising. In marine applications, the space is relatively ample, there is high voltage electricity, and the engine operating range is narrow, so it has been applied to a certain extent, but it is not very suitable for road vehicles, engineering machinery and other applications with small space, cost sensitivity and large changes in engine workload.

[0021] It can be seen that the existing ammonia supply system has the following problems: complex technology, large size, low efficiency, high cost, and usually only constant pressure and low temperature ammonia supply. In addition, if the ammonia internal combustion engine 300 has a large workload change, frequent load changes, and needs to adjust the liquid supply pressure according to the working conditions, the pressure response is poor, and there is a risk of gas binding at small flow rates.

[0022] The present invention proposes an ammonia fuel supply system for an ammonia internal combustion engine 300 to solve the above problems. Specifically, Figure 1 As shown, the ammonia fuel supply system according to the embodiment of the present invention includes a liquid ammonia supply component 100, an ammonia injection component 200 and a pumping component.

[0023] The liquid ammonia supply assembly 100 is used to supply liquid ammonia. The liquid ammonia supply assembly 100 of the embodiment of the present invention includes a liquid ammonia tank 110. The liquid ammonia tank 110 is used to store liquid ammonia. In some other embodiments, other containers can be used to store liquid ammonia. The liquid ammonia tank 110 has a certain thermal insulation performance, and the tank body does not need to be insulated, and it is sufficient to ensure that the ammonia in the tank does not significantly increase in temperature under direct sunlight. At room temperature, gas and liquid coexist in the ammonia tank, and the pressure is usually around 10 bar.

[0024] The liquid ammonia tank 110 is provided with a liquid outlet 111 and a pressurizing port 112. The liquid outlet 111 is used to output liquid ammonia. The liquid outlet 111 is arranged at the bottom of the liquid ammonia tank 110. The liquid ammonia in the tank flows to the liquid supply pipeline through the liquid outlet 111 at the bottom under the action of its own pressure. In some embodiments, an auxiliary suction pump can be installed, and a primary pump may be omitted.

[0025] In extremely cold regions, ammonia or inert gas (nitrogen) is filled into the liquid ammonia tank 110 through the pressurizing port 112 to make the pressure inside the tank meet the use requirements and ensure that both pumped ammonia and cooled ammonia can flow effectively. Therefore, a pump for discharging liquid from the liquid ammonia tank 110 is not necessary.

[0026] The liquid outlet 111 of this embodiment is connected to an ammonia filter 120 , and the liquid ammonia is filtered through the ammonia filter 120 .

[0027] The ammonia injection assembly 200 is connected to the ammonia internal combustion engine 300 for use. The ammonia injection assembly 200 is used to realize the injection of ammonia in the ammonia internal combustion engine 300. The ammonia injection assembly 200 includes an ammonia rail and a plurality of injectors. The injectors are connected to a plurality of driving cylinders of the internal combustion engine in a one-to-one correspondence, and the ammonia rail is connected to the plurality of injectors respectively.

[0028] The pumping assembly of the embodiment of the present invention includes a liquid ammonia pump 400, which is provided with a liquid ammonia boosting chamber 410 and a cooling expansion chamber 420, wherein the liquid ammonia boosting chamber 410 is used to pressurize liquid ammonia. The liquid ammonia boosting chamber 410 of this embodiment is provided with a liquid ammonia inlet 411 and a liquid ammonia outlet 412, the liquid ammonia inlet 411 is connected to the liquid outlet 111 through a liquid supply pipeline, and the liquid ammonia outlet 412 is connected to the ammonia injection assembly 200 through a pipeline.

[0029] The cooling expansion chamber 420 and the liquid ammonia boosting chamber 410 have a wall heat exchange relationship, and the cooling expansion chamber 420 is used to cool the liquid ammonia boosting chamber 410. The cooling expansion chamber 420 of the embodiment of the present invention has an expansion inlet 421 and an expansion outlet 422. The expansion inlet 421 is connected to the liquid outlet 111 through an expansion valve 430. When in use, the liquid ammonia supply component 100 supplies liquid ammonia to the liquid ammonia pump 400. The liquid ammonia is divided into two paths in the liquid ammonia pump 400, one of which enters from the liquid ammonia inlet 411, is pressurized through the liquid ammonia boosting chamber 410 to form high-pressure liquid ammonia, and then is pumped out from the liquid ammonia outlet 412 to the ammonia injection component 2 00, the ammonia is injected through the ammonia injection assembly 200 to supply ammonia for combustion consumption in the internal combustion engine 300, and the other way is vaporized and absorbs heat in the cooling expansion chamber 420 through the expansion valve 430, and the temperature of the liquid ammonia boost chamber 410 is reduced through the heat exchange between the liquid ammonia boost chamber 410 and the cooling expansion chamber 420, ensuring that the liquid ammonia is not vaporized and the pump can work normally to generate pressure. The liquid ammonia pump 400 is accurately pumped to the internal combustion engine for use according to demand without reflux. The present invention adopts a part of the liquid ammonia as the refrigerant, and realizes the cooling of the liquid ammonia pump 400 through the large latent heat of ammonia vaporization. It is suitable for the storage and transportation of liquid ammonia at room temperature, can effectively avoid gas binding, and realize precise pumping.

[0030] like Figure 2 As shown, the liquid ammonia pump 400 of the embodiment of the present invention includes a pump head 440 and a piston body 450, wherein the pump head 440 is provided with a piston cavity 441, and the piston body 450 is slidably arranged in the piston cavity 441 to form the above-mentioned liquid ammonia boosting cavity 410, and the cooling expansion cavity 420 is formed on the pump head 440. The cooling expansion cavity 420 of this embodiment is arranged around the liquid ammonia boosting cavity 410 to improve the heat exchange effect.

[0031] The present invention utilizes ammonia gasification to cool the pump head 440. After eliminating the gasification problem of the pump head 440, there is no need to worry about heat transfer. In some embodiments, the pump can be installed on the body of the ammonia internal combustion engine 300, and then driven by the power of the ammonia internal combustion engine 300, and the lubrication system can also be shared.

[0032] In some embodiments, the liquid ammonia pump 400 is an electrically controlled plunger pump, which controls the volume of the liquid ammonia boost chamber 410 during compression through an electromagnetic valve to change the flow rate of the compressed liquid, so as to dynamically adjust the supply according to the needs of the internal combustion engine, without the need for oil return, and the output pressure can reach 1,000 bar, with good pressure dynamic response.

[0033] The flow rate of the pump can be adjusted as needed. This is not limited to this example. In some other embodiments, heating, gasification, distribution, buffering and other devices can be added after the pump according to specific needs.

[0034] like Figure 2As shown, the liquid ammonia outlet 412 of the embodiment of the present invention is provided with a one-way valve 460 and a pressure relief valve 470, which are arranged in parallel, and the liquid ammonia inlet 411 is provided with a liquid inlet solenoid valve 4111, which is used to control the amount of liquid ammonia entering the liquid ammonia boosting chamber 410. When the piston body 450 moves downward, the liquid inlet solenoid valve 4111 opens, and when the piston body 450 moves upward, the closing time point of the liquid inlet solenoid valve 4111 is controlled according to the liquid ammonia delivery amount.

[0035] The flow direction of the one-way valve 460 is from the liquid ammonia boosting chamber 410 to the ammonia injection assembly 200. The one-way valve 460 is configured to open when the pressure on the inlet side of the one-way valve 460 is greater than a first preset value so that the liquid ammonia outlet 412 is connected to the ammonia injection assembly 200. During the upward movement of the piston body 450, when the ammonia liquid is pressurized to the pressure of the first preset value, the one-way valve 460 opens and the high-pressure ammonia is pumped out. When the piston body 450 has not yet reached the set height, the one-way valve 460 is in a closed state. When the piston body 450 is downward, the liquid ammonia will not flow back through the one-way valve 460, and the suction force generated by the downward movement of the piston body 450 is only used to absorb the supplied liquid ammonia.

[0036] The pressure relief valve 470 is configured to open when the outlet side pressure of the one-way valve 460 is greater than the second preset value so that the ammonia injection assembly 200 is connected to the liquid ammonia boost chamber 410 and communicates with the liquid ammonia inlet 411 when the liquid inlet solenoid valve 4111 is opened. In actual operation, high-pressure liquid ammonia is periodically pumped into the injector and the ammonia rail. When the pressure of the injector and the ammonia rail is too high, if ammonia is continued to be added, the injector or the ammonia rail will be damaged. In order to protect the injector and the ammonia rail at the rear end, the embodiment of the present invention is provided with a pressure relief valve 470. It can be understood that when the liquid ammonia pressure in the injector and the ammonia rail in the internal combustion engine is higher than the second preset value, the pressure relief valve 470 is opened to relieve the pressure of the liquid ammonia in the injector and the ammonia rail, and the pressure can be relieved to the supply end during the liquid inlet stage.

[0037] In some embodiments, the liquid ammonia inlet 411 is connected to a vent port, and the vent port is provided with a vent valve, which is used for release and purging during initial filling or maintenance.

[0038] Furthermore, the ammonia fuel supply system also includes an intake assembly 500 connected to the ammonia internal combustion engine 300. The intake assembly 500 realizes the intake of the ammonia internal combustion engine 300. In order to avoid pollution and waste, the expansion outlet 422 of the embodiment of the present invention is connected to the intake assembly 500 through a pipeline. The ammonia after cooling the pump head 440 can be recycled to the intake assembly 500 to serve as fuel.

[0039] Specifically, the air intake assembly 500 of the embodiment of the present invention includes an air intake pipe 510, a compressor 520 and a throttle 530. The compressor 520 and the throttle 530 are sequentially arranged in the air intake pipe 510. The air intake pipe 510 is provided with at least one first ammonia access point 511 connected to the expansion outlet 422. The number and position of the first ammonia access point 511 can be determined according to actual needs, such as Figure 1 As shown, the present invention is provided with a first ammonia access point 511 on the upstream side of the compressor 520, and first ammonia access points 511 are provided on the downstream side and the upstream side of the throttle 530. The expanded ammonia can be introduced into the intake pipe 510 from one of the first ammonia access points 511, or simultaneously introduced into the intake pipe 510 from multiple first ammonia access points 511. Depending on the type of the engine, the access position can be selected from the above-mentioned first ammonia access points 511.

[0040] In addition, the ammonia fuel supply system of the embodiment of the present invention also includes an exhaust component 600 connected to the ammonia internal combustion engine 300, and the exhaust component 600 is used to realize the exhaust of the ammonia internal combustion engine 300. The exhaust component 600 of the embodiment of the present invention includes an exhaust pipe 610 and an exhaust gas processor 620 arranged in the exhaust pipe 610. The exhaust gas processor 620 is provided with a second ammonia access point 621 connected to the expansion outlet 422. The expansion outlet 422 is connected to the second ammonia access point 621 through a pipeline. The ammonia after cooling the pump head 440 can be recycled to the exhaust gas processor 620 as a reactant for nitrogen oxides to reduce pollution emissions.

[0041] Furthermore, the embodiment of the present invention achieves the goal of gasifying ammonia and flowing it as needed to cool the pump chamber without causing pollution or waste.

[0042] The exhaust pipe 610 of the embodiment of the present invention is equipped with a vortex supercharger 611, which is drivingly connected to the compressor 520. The vortex supercharger 611 recovers the kinetic energy of the exhaust gas to drive the compressor 520 to operate.

[0043] The opening degree of the expansion valve 430 in the embodiment of the present invention can be adjusted. By controlling the expansion valve 430, the cooling ammonia flow rate can be adjusted, the temperature of the pump head 440 can be controlled within a reasonable range, and the emission parameters can also be adjusted.

[0044] Compared with the prior art which requires the use of an insulated ammonia tank, a two-stage pump, and the filling of low-temperature ammonia, the ammonia fuel supply system of the embodiment of the present invention does not require insulation, has no first-stage pump, uses room-temperature ammonia, solves the gas binding problem, and the ammonia pump is flexibly arranged and can be integrated with the engine. The cooled ammonia is effectively utilized by the engine without causing pollution or energy loss.

[0045] The present invention simplifies the design of the ammonia fuel supply system of the ammonia internal combustion engine 300, reduces energy consumption, and saves costs, thereby creating favorable conditions for improving system integration and reducing volume, expanding the application scope of the ammonia internal combustion engine 300, eliminating the need for low-temperature requirements for filling ammonia, and improving the convenience of ammonia transportation and storage, thereby indirectly reducing the use cost of the ammonia internal combustion engine 300.

[0046] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An ammonia fuel supply system for an ammonia internal combustion engine, characterized in that: include: A liquid ammonia supply assembly (100), used for supplying liquid ammonia; an ammonia injection assembly (200), connected to the ammonia internal combustion engine (300); A pumping assembly comprises a liquid ammonia pump (400), the liquid ammonia pump (400) being provided with a liquid ammonia boosting chamber (410) and a cooling expansion chamber (420) having a partition wall heat exchange relationship, the liquid ammonia boosting chamber (410) having a liquid ammonia inlet (411) and a liquid ammonia outlet (412), the liquid ammonia inlet (411) being connected to the liquid ammonia supply assembly (100), the liquid ammonia outlet (412) being connected to the ammonia injection assembly (200), the cooling expansion chamber (420) having an expansion inlet (421) and an expansion outlet (422), an expansion valve (430) being connected between the expansion inlet (421) and the liquid ammonia supply assembly (100).

2. The ammonia fuel supply system according to claim 1, characterized in that: The ammonia fuel supply system further comprises an air intake assembly (500) connected to the ammonia internal combustion engine (300), and the expansion outlet (422) is connected to the air intake assembly (500).

3. The ammonia fuel supply system according to claim 2, characterized in that: The air intake assembly (500) comprises an air intake pipe (510), a compressor (520) and a throttle valve (530) which are sequentially arranged on the air intake pipe (510), and the air intake pipe (510) is provided with at least one first ammonia access point (511) connected to the expansion outlet (422).

4. The ammonia fuel supply system according to claim 1, characterized in that: The ammonia fuel supply system further comprises an exhaust assembly (600) connected to the ammonia internal combustion engine (300), and the expansion outlet (422) is connected to the exhaust assembly (600).

5. The ammonia fuel supply system according to claim 4, characterized in that: The exhaust assembly (600) comprises an exhaust pipe (610) and an exhaust gas processor (620) arranged on the exhaust pipe (610); the exhaust gas processor (620) is provided with a second ammonia access point (621) connected to the expansion outlet (422).

6. The ammonia fuel supply system according to claim 1, characterized in that: The liquid ammonia pump (400) comprises a pump head (440) and a piston body (450); the pump head (440) is provided with a piston cavity (441); the piston body (450) is slidably disposed in the piston cavity (441) to form the liquid ammonia boosting cavity (410); and the cooling expansion cavity (420) is formed on the pump head (440).

7. The ammonia fuel supply system according to claim 6, characterized in that: The liquid ammonia outlet (412) is provided with a one-way valve (460) and a pressure relief valve (470) arranged in parallel, and the liquid ammonia inlet (411) is provided with a liquid inlet solenoid valve (4111). The flow direction of the one-way valve (460) is from the liquid ammonia boosting chamber (410) to the ammonia injection assembly (200). The one-way valve (460) is configured to open when the pressure on the inlet side of the one-way valve (460) is greater than a first preset value so that the liquid ammonia outlet (412) is connected to the ammonia injection assembly (200). The pressure relief valve (470) is configured to open when the pressure on the outlet side of the one-way valve (460) is greater than a second preset value so that the ammonia injection assembly (200) is connected to the liquid ammonia boosting chamber (410) and is connected to the liquid ammonia inlet (411) when the liquid inlet solenoid valve (4111) is opened.

8. The ammonia fuel supply system according to claim 1, characterized in that: The liquid ammonia supply assembly (100) comprises a liquid ammonia tank (110), wherein the liquid ammonia tank (110) is provided with a liquid outlet (111) and a pressurizing port (112), wherein the liquid outlet (111) is connected to the liquid ammonia inlet (411).

9. The ammonia fuel supply system according to claim 8, characterized in that: The liquid outlet (111) is connected to an ammonia filter (120).

10. The ammonia fuel supply system according to claim 1, characterized in that: The liquid ammonia inlet (411) is connected to a venting port, and the venting port is provided with a venting valve.

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