A vehicle-mounted high-pressure liquid ammonia supply and return control system and engine

Abstract

The present application relates to a vehicle-mounted high-pressure liquid ammonia supply and return control system and an engine. The system comprises: a liquid ammonia tank, a liquid ammonia pump mounted at the tank's liquid outlet; the pump's output end connected to a high-pressure plunger pump via a liquid inlet pipeline; a high-pressure liquid ammonia rail connected to the pump's output end; and a liquid return pipeline connected to the liquid return port of the liquid ammonia tank; a first-stage liquid inlet heat exchanger mounted on the liquid inlet pipeline; a liquid return heat exchanger mounted on the liquid return pipeline; and an on-board chiller thermally coupled to the first-stage liquid inlet heat exchanger and the liquid return heat exchanger. Direct injection is employed to optimize the combustion process and improve combustion efficiency. Heat exchange temperature control is performed during liquid inlet to ensure a liquid ammonia supply. During liquid return, the liquid ammonia temperature is prevented from rising and forming a gas-liquid mixed phase, thereby providing a stable and reliable liquid ammonia supply and return system for the engine.

Description

Technical Field

[0001] The present application relates to the field of automobile engine systems, and in particular to an on-vehicle high-pressure liquid ammonia supply and return control system and an engine. Background Art

[0002] Ammonia is a hydrogen-rich carrier fuel other than hydrogen. It contains no carbon and its complete combustion products are only nitrogen and water, making it a clean, renewable alternative fuel. Furthermore, ammonia offers significant advantages due to its low storage and transportation costs and mature production process.

[0003] Ammonia internal combustion engines have broad application prospects in multiple fields, including automobiles, aircraft, and ships. As the technology continues to develop and improve, ammonia internal combustion engines are expected to become an important alternative to traditional fuel engines in the future.

[0004] Among related technologies, the traditional technical solution mainly involves ammonia premix combustion, where ammonia is injected into the intake manifold and then ignited by diesel compression ignition or hydrogen ignition. The premixed combustion solution has two problems: high low-load N2O (nitrous oxide) emissions: Under low-load conditions, the low combustion temperature leads to high N2O emissions, which limits the increase in the ammonia blending ratio. High N2O emissions affect the environment; high-load explosion pressure limit: Under high-load conditions, the engine explosion pressure limit becomes the main factor limiting the increase in the ammonia blending ratio. Excessive explosion pressure can damage the engine. Summary of the Invention

[0005] The present application provides an on-vehicle high-pressure liquid ammonia supply and liquid return control system and an engine, which performs a first-stage heat exchange temperature control during liquid inlet to ensure that the ammonia supply is in liquid form, and prevents the liquid ammonia temperature from rising to form a gas-liquid mixed phase during liquid return, thereby providing a stable and reliable liquid ammonia supply and liquid return system for the engine, avoiding the ammonia premixed combustion method in the related art, which has high nitrous oxide emissions under low load conditions and limits the increase in the ammonia blending ratio under high load conditions.

[0006] In a first aspect, an embodiment of the present application provides a vehicle-mounted high-pressure liquid ammonia supply and return control system, comprising:

[0007] A liquid ammonia tank, wherein a liquid ammonia pump is installed at the liquid outlet of the liquid ammonia tank, the output end of the liquid ammonia pump is connected to a high-pressure plunger pump via a liquid inlet pipeline, the output end 1 of the high-pressure plunger pump is connected to a high-pressure liquid ammonia rail, the output end 2 of the high-pressure plunger pump is connected to a liquid return pipeline, and the liquid return pipeline is connected to the liquid return port of the liquid ammonia tank;

[0008] a first-stage liquid inlet heat exchanger, the first-stage liquid inlet heat exchanger being installed on the liquid inlet pipeline;

[0009] a liquid return heat exchanger, the liquid return heat exchanger being installed in the liquid return pipeline;

[0010] A vehicle-mounted chiller is thermally coupled to the first-stage liquid inlet heat exchanger and the liquid return heat exchanger.

[0011] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0012] A secondary liquid inlet heat exchanger is installed on the liquid inlet pipeline and thermally coupled with the vehicle-mounted chiller. Along the conveying direction of the liquid inlet pipeline, the secondary liquid inlet heat exchanger is located in front of the primary liquid inlet heat exchanger.

[0013] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0014] The liquid inlet electrically controlled valve is installed in the liquid inlet pipeline and is located between the first-stage liquid inlet heat exchanger and the high-pressure plunger pump.

[0015] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0016] A liquid return overflow valve is installed on the liquid return pipeline and is located between the liquid return heat exchanger and the high-pressure plunger pump, and the liquid return overflow valve is communicated with the liquid inlet pipeline.

[0017] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0018] An airbag-type pulse damper 1 is installed in the liquid inlet pipeline and is located between the first-stage liquid inlet heat exchanger and the high-pressure plunger pump.

[0019] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0020] The second airbag pulse damper is installed in the liquid return pipeline and is located between the liquid return heat exchanger and the liquid ammonia tank.

[0021] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0022] a second ball valve, one end of which is connected to the input end of the second airbag pulse damper;

[0023] A mechanical back-pressure valve, one end of which is connected in parallel with the liquid return pipeline, and the other end of which is connected with the other end of the second ball valve.

[0024] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0025] An ammonia rail safety valve is installed on the high-pressure liquid ammonia rail.

[0026] In combination with the first aspect, in one embodiment, the vehicle-mounted high-pressure liquid ammonia supply and return control system further includes:

[0027] A liquid return discharge stop valve is installed on the liquid return pipeline and is located between the liquid return heat exchanger and the high-pressure plunger pump.

[0028] In a second aspect, an embodiment of the present application provides an engine, which includes an on-board high-pressure liquid ammonia supply and liquid return control system as described in some of the above embodiments.

[0029] The beneficial effects of the technical solutions provided in the embodiments of the present application include:

[0030] The liquid ammonia pump controls the flow of low-pressure liquid ammonia into the high-pressure plunger pump. The high-pressure plunger pump's plunger pressurizes the ammonia and feeds it into the high-pressure liquid ammonia rail. The ammonia injector, installed on the high-pressure liquid ammonia rail, then injects it into the combustion chamber for combustion. Direct injection optimizes the combustion process, improves combustion efficiency, and helps reduce emissions. Furthermore, the coordination of a primary liquid inlet heat exchanger, a liquid return heat exchanger, and an onboard chiller ensures liquid ammonia is supplied in a liquid state. This prevents the liquid ammonia temperature from rising during liquid return, forming a gas-liquid mixture. This provides the engine with a stable and reliable liquid ammonia supply and return system, offering outstanding reliability, manageable costs, and a simple structure. This avoids the issues of ammonia premixed combustion in related technologies, which typically emits high nitrous oxide at low loads and limits the ammonia blend ratio at high loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 This is a structural diagram of the on-board high-pressure liquid ammonia supply and return control system.

[0033] Figure: 1. Liquid ammonia tank; 2. Liquid ammonia pump; 3. Liquid ammonia filling port; 4. Check valve; 5. Liquid and gas shut-off valves; 6. One-way valve (1); 7. Safety valve; 8. Shut-off valve; 9. Temperature sensor (1); 10. First-stage liquid inlet heat exchanger; 11. First airbag pulse dampener; 12. Second temperature sensor; 13. First pressure sensor; 14. Second-stage one-way valve; 15. Second-stage liquid inlet heat exchanger; 16. First pressure gauge; 17. Liquid inlet ball valve; 18. Liquid inlet electric control valve; 19. Liquid return relief valve; 20. High-pressure plunger pump; 21. High-pressure liquid ammonia rail. 22. Ammonia rail safety valve; 23. Liquid return ball valve; 24. Pressure gauge 2; 25. Liquid return discharge stop valve; 26. Liquid return safety valve; 27. Pressure sensor 2; 28. Temperature sensor 3; 29. ​​Liquid return heat exchanger; 30. Temperature sensor 4; 31. Airbag pulse damper 2; 32. Ball valve 1; 33. Electric pressure regulating valve; 34. Ball valve 2; 35. Mechanical back pressure valve; 36. Check valve 3; 37. Vent stop valve; 38. Ammonia tank safety valve; 39. Pressure gauge 3; 40. On-board chiller; 41. Liquid inlet and outlet air pressure regulating valve. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments 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 creative work are within the scope of protection of this application.

[0035] It's important to understand that ammonia is a hydrogen-rich carrier fuel, a carbon-free alternative. Its complete combustion products are nitrogen and water, making it a clean, renewable fuel alternative. Furthermore, ammonia offers significant advantages due to its low storage and transportation costs and mature production processes. Ammonia internal combustion engines hold broad application prospects in a variety of sectors, including automobiles, aircraft, and ships. With the continued development and improvement of technology, ammonia internal combustion engines are expected to become a significant alternative to traditional fuel engines in the future.

[0036] However, the traditional technical solution mainly relies on ammonia premix combustion, where ammonia is injected into the intake manifold and then ignited by diesel compression ignition or hydrogen ignition. The premixed combustion solution has two problems: high low-load N2O (nitrous oxide) emissions: Under low-load conditions, the low combustion temperature leads to high N2O emissions, which limits the increase in the ammonia blending ratio. High N2O emissions affect the environment; high-load explosion pressure limit: Under high-load conditions, the engine explosion pressure limit becomes the main factor limiting the increase in the ammonia blending ratio. Excessive explosion pressure can damage the engine.

[0037] The embodiments of the present application provide a vehicle-mounted high-pressure liquid ammonia supply and liquid return control system and an engine. A first-stage heat exchange temperature control is performed during liquid inlet to ensure that the ammonia supply is in a liquid state. During liquid return, the liquid ammonia temperature is prevented from rising to form a gas-liquid mixed phase. This provides a stable and reliable liquid ammonia supply and liquid return system for the engine, avoiding the ammonia premixed combustion method in the related art, which has high nitrous oxide emissions under low load conditions and limits the increase in the ammonia blending ratio under high load conditions.

[0038] First, as Figure 1 As shown, an embodiment of the present application provides a vehicle-mounted high-pressure liquid ammonia supply and liquid return control system, which includes: a liquid ammonia tank 1, a liquid ammonia pump 2 is installed at the liquid outlet of the liquid ammonia tank 1, the output end of the liquid ammonia pump 2 is connected to a high-pressure plunger pump 20 via a liquid inlet pipeline, the output end 1 of the high-pressure plunger pump 20 is connected to a high-pressure liquid ammonia rail 21, the output end 2 of the high-pressure plunger pump 20 is connected to a liquid return pipeline, and the liquid return pipeline is connected to the liquid return port of the liquid ammonia tank 1; a first-stage liquid inlet heat exchanger 10, the first-stage liquid inlet heat exchanger 10 is installed on the liquid inlet pipeline; a liquid return heat exchanger 29, the liquid return heat exchanger 29 is installed on the liquid return pipeline; and an on-board chiller 40, the on-board chiller 40 is thermally coupled with the first-stage liquid inlet heat exchanger 10 and the liquid return heat exchanger 29.

[0039] The liquid ammonia pump 2 controls the flow of low-pressure liquid ammonia into the high-pressure plunger pump 20. The ammonia is then pressurized by the plunger of the high-pressure plunger pump 20 and fed into the high-pressure liquid ammonia rail 21. The ammonia is then injected into the combustion chamber by a liquid ammonia injector mounted on the high-pressure liquid ammonia rail 21 for combustion and work. Direct injection optimizes the combustion process, improves combustion efficiency, and helps reduce emissions. Simultaneously, the first-stage liquid inlet heat exchanger 10, the liquid return heat exchanger 29, and the onboard chiller 40 coordinate to perform a first-stage heat exchange temperature control during liquid inlet, ensuring that the ammonia supply is liquid. During liquid return, the liquid ammonia temperature is prevented from rising and forming a gas-liquid mixed phase. This provides the engine with a stable and reliable liquid ammonia supply and liquid return system, offering outstanding reliability, manageable costs, and a simple structure. This avoids the problems of the ammonia premixed combustion method in related technologies, which has high nitrous oxide emissions at low loads and limits the increase in the ammonia blending ratio at high loads.

[0040] In combination with the first aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and return control system further includes a secondary liquid inlet heat exchanger 15, which is installed in the liquid inlet pipeline and thermally coupled to the on-board chiller 40. Along the delivery direction of the liquid inlet pipeline, the secondary liquid inlet heat exchanger 15 is located in front of the primary liquid inlet heat exchanger 10. Exemplarily, the liquid cooled by the primary liquid inlet heat exchanger 10 enters the secondary liquid inlet heat exchanger 15, where it is further cooled to maintain the liquid ammonia temperature and ensure a stable liquid phase of the supplied ammonia.

[0041] In combination with the first aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and return control system further includes an electrically controlled liquid inlet valve 18, which is installed in the liquid inlet pipeline and located between the primary liquid inlet heat exchanger 10 and the high-pressure plunger pump 20. For example, the high-pressure liquid ammonia supply rate is calculated based on a rail pressure feedback signal from the high-pressure liquid ammonia rail 21 and a throttle signal, and the liquid inlet opening can be controlled by the electrically controlled liquid inlet valve 18.

[0042] In combination with the first aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and return liquid control system further includes a return liquid relief valve 19, which is installed in the return liquid pipeline and located between the return liquid heat exchanger 29 and the high-pressure plunger pump 20. The return liquid relief valve 19 is also connected to the liquid inlet circuit. For example, the return liquid is controlled by the return liquid relief valve 19 to precisely control the flow of low-pressure liquid ammonia entering the high-pressure plunger pump 20.

[0043] In combination with the first aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and return control system further includes an airbag-type pulse damper 11, which is installed in the liquid inlet pipeline and located between the first-stage liquid inlet heat exchanger 10 and the high-pressure plunger pump 20. Exemplarily, after passing through the first-stage liquid inlet heat exchanger 10, the liquid continues to flow toward the airbag-type pulse damper 11 to reduce flow fluctuations.

[0044] In combination with the first aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and return control system further includes a second airbag-type pulse damper 31, which is installed in the return liquid pipeline and located between the return liquid heat exchanger 29 and the liquid ammonia tank 1. Exemplarily, the second airbag-type pulse damper 31 reduces fluctuations in the liquid flow in the return liquid pipeline.

[0045] In combination with the first aspect, in one embodiment, Figure 1As shown, the on-board high-pressure liquid ammonia supply and return control system also includes: a second ball valve 34, one end of which is connected to the input end of the second airbag pulse dampener 31; and a mechanical backpressure valve 35, one end of which is connected in parallel with the return line and the other end of which is connected to the other end of the second ball valve 34. Exemplarily, the system comprises the second ball valve 34 and the mechanical backpressure valve 35 in parallel, along with the second airbag pulse dampener 31, primarily to maintain pressure stability, protect equipment, and optimize pump performance. To maintain pressure stability, the mechanical backpressure valve 35 is used to maintain a constant pressure, while the second ball valve 34 assists in controlling fluid flow. The combination of the second airbag pulse dampener 31 and the mechanical backpressure valve 35 can reduce the risk of water hammer to the system and lower the peak value of flow rate fluctuations, thereby protecting pipelines, elbows, and joints from the impact of pressure fluctuations.

[0046] In combination with the first aspect, in one embodiment, Figure 1 As shown, the onboard high-pressure liquid ammonia supply and return control system also includes an ammonia rail safety valve 22, which is installed on the high-pressure liquid ammonia rail 21. Exemplarily, the ammonia rail safety valve 22 is installed on the high-pressure liquid ammonia rail 21 to monitor and control the rail pressure of the high-pressure liquid ammonia rail 21 to ensure it does not exceed a certain level. When the pressure within the rail reaches or exceeds the threshold set by the ammonia rail safety valve 22, the ammonia rail safety valve 22 automatically opens, releasing some liquid ammonia to reduce the pressure within the rail and prevent equipment damage or safety accidents caused by excessive pressure.

[0047] Furthermore, the ammonia rail safety valve 22 may be connected to the liquid inlet pipeline, so that the liquid ammonia discharged from the ammonia rail safety valve 22 can be returned to the pipeline.

[0048] In combination with the first aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and liquid return control system further includes a liquid return discharge stop valve 25, which is installed in the liquid return pipeline and is located between the liquid return heat exchanger 29 and the high-pressure plunger pump 20. Exemplarily, the reflux liquid passes through the liquid return discharge stop valve 25 and can be discharged through the liquid return discharge stop valve 25 if necessary.

[0049] In summary, if Figure 1As shown, some components are connected by dotted lines to indicate that these components can be connected to the outside world, so that the liquid ammonia or gaseous ammonia at the location of these components can be emptied to the outside world to ensure the safety of the system. The on-board high-pressure liquid ammonia supply and return liquid control system is mainly used to supply liquid ammonia and convert it into the required pressure and temperature state. The following is the function of each device and its role in the entire system: liquid ammonia tank 1 stores liquid ammonia; liquid ammonia pump 2 extracts liquid ammonia and sends it to subsequent equipment; liquid ammonia filling port 3 is used to add new liquid ammonia to the storage tank; check valve 4 prevents liquid backflow; liquid and gas outlet shut-off valve 5 controls the flow of liquid and gas; one-way valve 6 only allows liquid to flow in one direction; safety valve 7 automatically releases pressure to protect the system when the pressure is too high; shut-off valve 8 is used to completely close or open the flow of liquid. Temperature sensor 1 (9) monitors the liquid temperature; primary inlet heat exchanger 10 preheats the liquid entering the system; bladder-type pulse dampener 1 (11) reduces fluctuations in the liquid flow; temperature sensor 2 (12) monitors the liquid temperature after passing through the heat exchanger; pressure sensor 1 (13) monitors the system pressure; check valve 2 (14) allows liquid flow in only one direction; secondary inlet heat exchanger 15 further heats the liquid; pressure gauge 1 (16) displays the current pressure; inlet ball valve 17 controls the liquid flow; and inlet electric control valve 18 electronically controls the liquid flow. This is the liquid inlet control equipment before liquid ammonia enters the high-pressure plunger pump 20.

[0050] It also includes the functions of the following equipment and their role in the entire system: return liquid overflow valve 19, when the pressure exceeds the set value, the liquid will return to the storage tank through this valve; high-pressure plunger pump 20 increases the pressure of the liquid so that it can be transported to other equipment; high-pressure liquid ammonia rail 21 is a pipeline that withstands high pressure; ammonia rail safety valve 22 automatically releases pressure when the pressure in the rail is too high; return liquid ball valve 23 controls the flow of return liquid; pressure gauge 24 displays the current pressure value; return liquid discharge stop valve 25 controls the discharge of return liquid; return liquid safety valve 26 automatically releases pressure when the return liquid pressure is too high; pressure sensor 2 27 monitors the pressure of the system; temperature sensor 3 28 monitors the temperature of the liquid; return liquid heat exchanger 29 cools the return liquid The liquid return system consists of a liquid return valve (32), a temperature sensor (4), and a bladder-type pulse damper (2). The ball valve (32) controls the flow of the liquid. The electronically controlled pressure regulating valve (33) electronically adjusts the liquid pressure. The ball valve (2), also known as the back pressure valve, controls the flow of the liquid. A mechanical back pressure valve (35) maintains a constant outlet pressure. A check valve (36) allows liquid to flow in only one direction. A vent valve (37) controls gas emissions. The ammonia tank safety valve (38) automatically releases pressure if the pressure in the liquid ammonia tank (1) is too high. A pressure gauge (39) displays the current pressure. The onboard chiller (40) cools the liquid in the system. The inlet and outlet pressure regulating valves (41) maintain a constant pressure by adjusting the inflow and outflow of liquid. The above describes the liquid return control equipment after liquid ammonia enters the high-pressure plunger pump (20).

[0051] This system uses a series of heat exchangers (primary inlet heat exchanger 10, secondary inlet heat exchanger 15, and return heat exchanger 29) and a liquid ammonia pump 2 to adjust the temperature and pressure, ultimately achieving the desired conditions. The system is also equipped with multiple safety valves (safety valve 7, ammonia rail safety valve 22, return safety valve 26, and ammonia tank safety valve 38) and pressure gauges (pressure gauge 1 16, pressure gauge 24, and pressure gauge 39) to ensure safe and accurate operation.

[0052] Specifically, the system's operating process can be divided into the following steps: Liquid ammonia is pumped from the liquid ammonia tank 1 by a liquid ammonia pump 2. The extracted liquid ammonia passes through a check valve 4, a liquid and gas shut-off valve 5, and a one-way valve 6, ensuring that the liquid can only flow in one direction. The liquid then enters the first-stage liquid inlet heat exchanger 10, where it is cooled by heat exchange. After passing through the first-stage liquid inlet heat exchanger 10, the liquid continues to flow through the bladder-type pulse dampener 11 to reduce flow fluctuations. A temperature sensor 2 12 monitors the liquid temperature after passing through the first-stage liquid inlet heat exchanger 10. A pressure sensor 13 monitors the overall system pressure. A one-way valve 14 again ensures that the liquid can only flow in one direction. The liquid then enters the second-stage liquid inlet heat exchanger 15, where it is further cooled along with the return liquid, maintaining the liquid ammonia temperature and ensuring a stable ammonia supply. A high-pressure plunger pump 20 pressurizes the liquid so that it can pass through the high-pressure liquid ammonia rail 21. An ammonia rail safety valve 22 is installed on the high-pressure liquid ammonia rail 21 to prevent excessive pressure within the rail. The return ball valve 23 controls the flow of the returning liquid. The returning liquid passes through pressure gauge 24 and return drain shutoff valve 25 and can be discharged through these valves if necessary. The returning liquid also passes through return safety valve 26 to prevent excessive pressure. The returning liquid enters the return heat exchanger 29, where it is cooled. The cooled liquid passes through temperature sensor 4 30 to monitor its temperature. The bladder-type pulse dampener 2 31 further reduces fluctuations in the liquid flow. Ball valve 1 32 controls the liquid flow. The electrically controlled pressure regulating valve 33 electronically adjusts the liquid pressure. Another ball valve 2 34 controls the liquid flow. A mechanical backpressure valve 35 maintains a constant outlet pressure. Check valve 3 36 ensures that the liquid can only flow in one direction. The vent shutoff valve 37 controls the discharge of gases. The ammonia tank safety valve 38 automatically releases pressure in the liquid ammonia tank 1 if the pressure is too high. The onboard chiller 40 cools the liquid in the system. The inlet and outlet pressure regulating valve 41 maintains a constant pressure by regulating the inflow and outflow of liquid.

[0053] Important feature control schemes and strategies are as follows:

[0054] Liquid inlet pressure regulation: Liquid ammonia pump 2 is used to supply low-pressure liquid ammonia, and the pressure sensor 13 at the liquid supply outlet is used as feedback to control the pumping frequency of liquid ammonia pump 2 to achieve the purpose of controlling the liquid supply pressure.

[0055] Inlet liquid temperature control: The onboard chiller 40 is used to control the inlet liquid temperature through two-stage heat exchange (the first-stage inlet liquid heat exchanger 10 and the second-stage inlet liquid heat exchanger 15) to ensure that the ammonia supply is in liquid form. At the same time, the abnormal return liquid from the oil rail is cooled (the return liquid heat exchanger 29) to prevent the liquid ammonia temperature from rising and forming a gas-liquid mixed phase.

[0056] High-pressure liquid ammonia quantitative supply: The high-pressure liquid ammonia supply amount is calculated based on the rail pressure feedback signal of the high-pressure liquid ammonia rail 21 and the throttle signal. The liquid inlet opening is then controlled by the liquid inlet electric control valve 18, and the return liquid back pressure is controlled by the return liquid relief valve 19. The low-pressure liquid ammonia flow entering the high-pressure plunger pump 20 is precisely controlled. The low-pressure liquid ammonia is pressurized by the high-pressure plunger pump 20 and enters the high-pressure liquid ammonia rail 21. It is then injected into the combustion chamber through the liquid ammonia injector of the high-pressure liquid ammonia rail 21 to burn and produce work.

[0057] Return liquid pressure and temperature regulation: A set of pressure regulating devices is installed at the return port of the gas cylinder: it consists of an electronically controlled pressure regulating valve 33 and a mechanical back pressure valve 35 in parallel, and an air bag pulse damper 31 is configured to slow down the pressure wave; the vehicle-mounted chiller 40 and the return liquid heat exchanger 29 are used to control the heat exchange and temperature control of the return liquid to ensure that the return liquid is in liquid state and the supply pressure and liquid phase are stable.

[0058] Safety control and maintenance convenience design: Safety valves (safety valve 7, ammonia rail safety valve 22, liquid return safety valve 26 and ammonia tank safety valve 38) are designed for the liquid inlet and return lines of liquid ammonia tank 1 to prevent overpressure failures caused by high temperature and equipment abnormalities. At the same time, multiple stop valves (liquid and gas outlet stop valve 5, stop valve 8, liquid return discharge stop valve 25 and vent stop valve 37) and ball valves (liquid inlet ball valve 17, liquid return ball valve 23, ball valve 1 32 and ball valve 2 34) are set on the liquid inlet and return lines to effectively cut off and empty the system and pipelines during maintenance to prevent ammonia poisoning and injury during maintenance.

[0059] In a second aspect, an embodiment of the present application provides an engine, which includes a vehicle-mounted high-pressure liquid ammonia supply and liquid return control system as described in some of the above embodiments, such as Figure 1As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system includes: a liquid ammonia tank 1, a liquid ammonia pump 2 is installed at the liquid outlet of the liquid ammonia tank 1, the output end of the liquid ammonia pump 2 is connected to a high-pressure plunger pump 20 via a liquid inlet pipeline, the output end 1 of the high-pressure plunger pump 20 is connected to a high-pressure liquid ammonia rail 21, the output end 2 of the high-pressure plunger pump 20 is connected to a liquid return pipeline, and the liquid return pipeline is connected to the liquid return port of the liquid ammonia tank 1; a first-stage liquid inlet heat exchanger 10, the first-stage liquid inlet heat exchanger 10 is installed on the liquid inlet pipeline; a liquid return heat exchanger 29, the liquid return heat exchanger 29 is installed on the liquid return pipeline; and an on-board chiller 40, the on-board chiller 40 is thermally coupled with the first-stage liquid inlet heat exchanger 10 and the liquid return heat exchanger 29.

[0060] The liquid ammonia pump 2 controls the flow of low-pressure liquid ammonia into the high-pressure plunger pump 20. The ammonia is then pressurized by the plunger of the high-pressure plunger pump 20 and fed into the high-pressure liquid ammonia rail 21. The ammonia is then injected into the combustion chamber by a liquid ammonia injector mounted on the high-pressure liquid ammonia rail 21 for combustion and work. Direct injection optimizes the combustion process, improves combustion efficiency, and helps reduce emissions. Simultaneously, the first-stage liquid inlet heat exchanger 10, the liquid return heat exchanger 29, and the onboard chiller 40 coordinate to perform a first-stage heat exchange temperature control during liquid inlet, ensuring that the ammonia supply is liquid. During liquid return, the liquid ammonia temperature is prevented from rising and forming a gas-liquid mixed phase. This provides the engine with a stable and reliable liquid ammonia supply and liquid return system, offering outstanding reliability, manageable costs, and a simple structure. This avoids the problems of the ammonia premixed combustion method in related technologies, which has high nitrous oxide emissions at low loads and limits the increase in the ammonia blending ratio at high loads.

[0061] In conjunction with the second aspect, in one embodiment, Figure 1 As shown, the on-board high-pressure liquid ammonia supply and return control system further includes a secondary liquid inlet heat exchanger 15, which is installed in the liquid inlet pipeline and thermally coupled to the on-board chiller 40. Along the delivery direction of the liquid inlet pipeline, the secondary liquid inlet heat exchanger 15 is located in front of the primary liquid inlet heat exchanger 10. Exemplarily, the liquid cooled by the primary liquid inlet heat exchanger 10 enters the secondary liquid inlet heat exchanger 15, where it is further cooled to maintain the liquid ammonia temperature and ensure a stable liquid phase of the supplied ammonia.

[0062] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application 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 cannot be understood as a limitation on this application. 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 an indirect connection 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 this application can be understood according to the specific circumstances.

[0063] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any 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 comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0064] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. 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 application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A vehicle-mounted high-pressure liquid ammonia supply and return liquid control system, characterized in that: It includes: A liquid ammonia tank (1), wherein a liquid ammonia pump (2) is installed at the liquid outlet of the liquid ammonia tank (1), the output end of the liquid ammonia pump (2) is connected to a high-pressure plunger pump (20) via a liquid inlet pipeline, the output end 1 of the high-pressure plunger pump (20) is connected to a high-pressure liquid ammonia rail (21), the output end 2 of the high-pressure plunger pump (20) is connected to a liquid return pipeline, and the liquid return pipeline is connected to the liquid return port of the liquid ammonia tank (1); a first-stage liquid inlet heat exchanger (10), the first-stage liquid inlet heat exchanger (10) being installed on the liquid inlet pipeline; a liquid return heat exchanger (29), the liquid return heat exchanger (29) being installed on the liquid return pipeline; An on-board chiller (40) is thermally coupled to the first-stage liquid inlet heat exchanger (10) and the liquid return heat exchanger (29).

2. The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: A secondary liquid inlet heat exchanger (15) is installed on the liquid inlet pipeline and is thermally coupled to the vehicle-mounted chiller (40). Along the conveying direction of the liquid inlet pipeline, the secondary liquid inlet heat exchanger (15) is located in front of the primary liquid inlet heat exchanger (10).

3. The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: A liquid inlet electric control valve (18) is installed in the liquid inlet pipeline and is located between the first-stage liquid inlet heat exchanger (10) and the high-pressure plunger pump (20).

4. The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: A liquid return overflow valve (19) is installed on the liquid return pipeline and is located between the liquid return heat exchanger (29) and the high-pressure plunger pump (20), and the liquid return overflow valve (19) is connected to the liquid inlet pipeline.

5. The vehicle-mounted high-pressure liquid ammonia supply and return liquid control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: An airbag-type pulse damper (11) is installed on the liquid inlet pipeline and is located between the first-stage liquid inlet heat exchanger (10) and the high-pressure plunger pump (20).

6. The vehicle-mounted high-pressure liquid ammonia supply and return control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: The second airbag pulse damper (31) is installed in the liquid return pipeline and is located between the liquid return heat exchanger (29) and the liquid ammonia tank (1).

7. The vehicle-mounted high-pressure liquid ammonia supply and return control system according to claim 6, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: A second ball valve (34), one end of which is connected to the input end of the second airbag pulse damper (31); A mechanical back pressure valve (35), one end of which is connected in parallel to the liquid return pipeline, and the other end of which is communicated with the other end of the second ball valve (34).

8. The vehicle-mounted high-pressure liquid ammonia supply and return control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: An ammonia rail safety valve (22) is installed on the high-pressure liquid ammonia rail (21).

9. The vehicle-mounted high-pressure liquid ammonia supply and return control system according to claim 1, characterized in that: The vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: A liquid return discharge stop valve (25) is installed on the liquid return pipeline and is located between the liquid return heat exchanger (29) and the high-pressure plunger pump (20).

10. An engine, characterized in that: It includes the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system according to any one of claims 1 to 9.

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