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

Abstract

The invention relates to a vehicle-mounted high-pressure liquid ammonia supply and liquid return control system and an engine, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system comprises a liquid ammonia tank, a liquid ammonia pump is mounted at a liquid outlet of the liquid ammonia tank, the output end of the liquid ammonia pump is communicated with a high-pressure plunger pump through a liquid inlet pipeline, the first output end of the high-pressure plunger pump is communicated with a high-pressure liquid ammonia rail, and the second output end of the high-pressure plunger pump is communicated with a low-pressure liquid ammonia rail; the output end II of the high-pressure plunger pump is communicated with a liquid return pipeline; the liquid return pipeline is communicated with a liquid return opening of the liquid ammonia tank; the first-stage liquid inlet heat exchanger is mounted on the liquid inlet pipeline; the liquid return heat exchanger is mounted on the liquid return pipeline; and the vehicle-mounted water cooling machine is thermally coupled with the primary liquid inlet heat exchanger and the liquid return heat exchanger. In-cylinder direct injection is adopted, the combustion process is optimized, and the combustion efficiency is improved. Heat exchange temperature control is carried out during liquid feeding, it is guaranteed that ammonia supply is in a liquid state, the temperature of liquid ammonia is prevented from rising to form a gas-liquid mixed phase during liquid returning, and a stable and reliable liquid ammonia supply and liquid returning system is provided for an engine.

Description

Technical Field

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

[0002] Ammonia is a hydrogen-rich carrier fuel other than hydrogen. Ammonia does not contain carbon, and the only products of complete combustion are nitrogen and water. It is a clean, renewable alternative fuel. At the same time, ammonia has low storage and transportation costs and a very mature production process, so it has great application advantages.

[0003] Ammonia internal combustion engines have broad application prospects in many fields, including automobiles, airplanes, ships, etc. With the continuous development and improvement of technology, ammonia internal combustion engines are expected to become an important choice to replace traditional fuel engines in the future.

[0004] In the related technology, the traditional technical solution is mainly ammonia premixed combustion, in which ammonia is injected into the intake manifold, and then burned by diesel compression ignition or hydrogen ignition. There are two problems with the premixed combustion solution: high low-load N2O (nitrous oxide) emissions: under low-load conditions, due to the low combustion temperature, N2O emissions are high, which limits the increase in the ammonia blending ratio, and high N2O emissions affect the environment; high-load explosion pressure limit: under high-load conditions, the engine explosion pressure boundary 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 a vehicle-mounted high-pressure liquid ammonia supply and liquid return control system and an engine, which performs a primary heat exchange temperature control during liquid intake 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, the problem of high nitrous oxide emissions under low load conditions and limiting 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 liquid return control system, which includes:

[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 is installed on the liquid inlet pipeline;

[0009] A liquid return heat exchanger, the liquid return heat exchanger is installed on the liquid return pipeline;

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

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

[0014] The liquid inlet electric control 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 implementation, the vehicle-mounted high-pressure liquid ammonia supply and liquid 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 implementation, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes:

[0018] An airbag-type pulse damper 1 is installed on 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 implementation, the vehicle-mounted high-pressure liquid ammonia supply and liquid 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 implementation, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes:

[0022] A second ball valve, one end of which is connected to an 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 implementation, the vehicle-mounted high-pressure liquid ammonia supply and liquid 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 implementation, the vehicle-mounted high-pressure liquid ammonia supply and liquid 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 brought by the technical solution provided in the embodiments of the present application include:

[0030] The liquid ammonia pump can control the low-pressure liquid ammonia entering the high-pressure plunger pump, and the liquid ammonia is pressurized by the plunger of the high-pressure plunger pump to enter the high-pressure liquid ammonia rail, and then injected into the combustion chamber through the liquid ammonia injector installed on the high-pressure liquid ammonia rail for combustion and work. The direct injection method in the cylinder optimizes the combustion process, improves the combustion efficiency, and helps to reduce emissions. At the same time, with the cooperation of the first-level liquid inlet heat exchanger, the liquid return heat exchanger and the on-board chiller, the first-level heat exchange temperature control is carried out during the liquid inlet to ensure that the ammonia supply is liquid, and the liquid ammonia temperature is prevented from rising to form a gas-liquid mixed phase during the liquid return, providing the engine with a stable and reliable liquid ammonia supply and liquid return system, which has the advantages of outstanding reliability, controllable cost and simple structure, and avoids the ammonia premixed combustion method in the related technology, which has high nitrous oxide emissions under low load conditions and limits the increase of ammonia blending ratio under high load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 creative work.

[0032] Figure 1 This is a schematic diagram of the structure of the vehicle-mounted high-pressure liquid ammonia supply and return liquid control system.

[0033] In the figure: 1. Liquid ammonia tank; 2. Liquid ammonia pump; 3. Liquid ammonia filling port; 4. Check valve; 5. Liquid and gas outlet stop valve; 6. One-way valve 1; 7. Safety valve; 8. Stop valve; 9. Temperature sensor 1; 10. Primary liquid inlet heat exchanger; 11. Airbag pulse damper 1; 12. Temperature sensor 2; 13. Pressure sensor 1; 14. One-way valve 2; 15. Secondary liquid inlet heat exchanger; 16. Pressure gauge 1; 17. Liquid inlet ball valve; 18. Liquid inlet electric control valve; 19. Liquid return overflow 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 solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] It is important to understand that ammonia is a hydrogen-rich carrier fuel other than hydrogen, and ammonia does not contain carbon. The only products of complete combustion are nitrogen and water. It is a clean, renewable alternative fuel. At the same time, ammonia has low storage and transportation costs, and its production process is very mature, so it has great application advantages. Ammonia internal combustion engines have broad application prospects in many fields, including automobiles, airplanes, ships, etc. With the continuous development and improvement of technology, ammonia internal combustion engines are expected to become an important choice to replace traditional fuel engines in the future.

[0036] However, the traditional technical solution is mainly ammonia premixed combustion, where ammonia is injected into the intake manifold and then ignited by diesel compression ignition or hydrogen ignition. There are two problems with the premixed combustion solution: high N2O (nitrous oxide) emissions at low loads: under low load conditions, due to the low combustion temperature, N2O emissions are high, which limits the increase in the ammonia blending ratio, and high N2O emissions affect the environment; high load explosion pressure limit: under high load conditions, the engine explosion pressure boundary becomes the main factor limiting the increase in the ammonia blending ratio. Excessive explosion pressure can damage the engine.

[0037] The embodiment of the present application provides a vehicle-mounted high-pressure liquid ammonia supply and liquid return control system and an engine, which performs a primary heat exchange temperature control during liquid intake 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, the problem of high nitrous oxide emissions under low load conditions and limiting 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 primary liquid inlet heat exchanger 10, the primary 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 primary liquid inlet heat exchanger 10 and the liquid return heat exchanger 29.

[0039] The liquid ammonia pump 2 can control the low-pressure liquid ammonia entering the high-pressure plunger pump 20, and the liquid ammonia is pressurized by the plunger of the high-pressure plunger pump 20 to enter the high-pressure liquid ammonia rail 21, and then is injected into the combustion chamber by the liquid ammonia injector installed on the high-pressure liquid ammonia rail 21 to burn and do work. The direct injection method in the cylinder is adopted to optimize the combustion process, improve the combustion efficiency, and help reduce emissions. At the same time, with the cooperation of the first-level liquid inlet heat exchanger 10, the liquid return heat exchanger 29 and the on-board chiller 40, the first-level heat exchange temperature control is performed during the liquid inlet to ensure that the ammonia supply is liquid, and the liquid ammonia temperature is prevented from rising to form a gas-liquid mixed phase during the liquid return, providing the engine with a stable and reliable liquid ammonia supply and liquid return system, which has the advantages of outstanding reliability, controllable cost and simple structure, and avoids the ammonia premixed combustion method in the related technology, which has high nitrous oxide emissions under low load conditions and limits the increase of the ammonia blending ratio under high load conditions.

[0040] In combination with the first aspect, in one embodiment, Figure 1 As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes: a secondary liquid inlet heat exchanger 15, which is installed on the liquid inlet pipeline and thermally coupled with 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. Exemplarily, the liquid cooled by the primary liquid inlet heat exchanger 10 enters the secondary liquid inlet heat exchanger 15, where it will be further cooled to maintain the liquid ammonia temperature and ensure the stability of the ammonia supply liquid phase.

[0041] In combination with the first aspect, in one embodiment, Figure 1 As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes: a liquid inlet electric control valve 18, which is installed in the liquid inlet pipeline and is located between the primary liquid inlet heat exchanger 10 and the high-pressure plunger pump 20. Exemplarily, 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, and the liquid inlet opening can be controlled by the liquid inlet electric control valve 18.

[0042] In combination with the first aspect, in one embodiment, Figure 1 As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes: a liquid return relief valve 19, 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, and the liquid return relief valve 19 is connected to the liquid inlet circuit. Exemplarily, the liquid return is controlled by the liquid return relief valve 19 to accurately control the flow rate 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 vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes: an airbag 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 to the airbag pulse damper 11 to reduce fluctuations in the flow.

[0044] In combination with the first aspect, in one embodiment, Figure 1 As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes: an airbag-type pulse damper 2 31, which is installed in the liquid return pipeline and located between the liquid return heat exchanger 29 and the liquid ammonia tank 1. Exemplarily, in the liquid return route, the airbag-type pulse damper 2 31 reduces fluctuations in liquid flow.

[0045] In combination with the first aspect, in one embodiment, Figure 1As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system also includes: a ball valve 2 34, one end of which is connected to the input end of the airbag pulse damper 2 31; a mechanical back pressure valve 35, one end of which is connected in parallel with the liquid return pipeline, and the other end of which is connected to the other end of the ball valve 2 34. Exemplarily, the ball valve 2 34 and the mechanical back pressure valve 35 are connected in parallel, and the airbag pulse damper 2 31 is configured at the same time, which mainly plays the role of maintaining pressure stability, protecting equipment and optimizing pump working performance. To maintain pressure stability, the mechanical back pressure valve 35 is used to maintain a constant pressure, and the ball valve 2 34 plays the role of assisting in controlling the fluid on and off. The airbag pulse damper 2 31 and the mechanical back pressure valve 35 are used in conjunction to reduce the harm of water hammer to the system and reduce the peak value of flow velocity fluctuation, thereby protecting the pipeline, elbows and joints from the impact of pressure fluctuations.

[0046] 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: 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, and the ammonia rail safety valve 22 monitors and controls the rail pressure of the high-pressure liquid ammonia rail 21 to ensure that it is not too high. When the pressure in the rail reaches or exceeds the threshold set by the ammonia rail safety valve 22, the ammonia rail safety valve 22 will automatically open and release part of the liquid ammonia to reduce the pressure in 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 vehicle-mounted 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 parts are connected by dotted lines to indicate that these parts can be connected to the outside world, so that the liquid ammonia or gas ammonia at the location of these parts can be emptied to the outside world to ensure the safety of the system. The on-board high-pressure liquid ammonia supply and liquid return control system is mainly used to supply liquid ammonia and convert it into the required pressure and temperature state. The following is the role 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 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 19 monitors the temperature of the liquid; the first-stage liquid inlet heat exchanger 10 preheats the liquid entering the system; the airbag pulse damper 11 reduces the fluctuation in the liquid flow; the temperature sensor 2 12 monitors the temperature of the liquid after passing through the heat exchanger; the pressure sensor 13 monitors the pressure of the system; the one-way valve 2 14 only allows the liquid to flow in one direction; the second-stage liquid inlet heat exchanger 15 further heats the liquid; the pressure gauge 16: displays the current pressure value; the liquid inlet ball valve 17 controls the inflow of the liquid; the liquid inlet electric control valve 18 controls the inflow of the liquid electronically. The above is the liquid inlet control equipment before the liquid ammonia enters the high-pressure plunger pump 20.

[0050] It also includes the functions of the following equipment and their functions in the entire system: liquid return 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; liquid return ball valve 23 controls the flow of reflux liquid; pressure gauge 24 displays the current pressure value; liquid return discharge stop valve 25 controls the discharge of reflux liquid; liquid return safety valve 26 automatically releases pressure when the reflux 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; liquid return heat exchanger 29 cools the reflux liquid body; temperature sensor 4 30 monitors the temperature of the liquid after passing through the return liquid heat exchanger 29; airbag pulse damper 2 31 reduces the fluctuation in the liquid flow; ball valve 1 32 controls the flow of the liquid; the electric pressure regulating valve 33 adjusts the pressure of the liquid electronically; ball valve 2 34 controls the flow of the liquid; mechanical back pressure valve 35 maintains a certain outlet pressure; one-way valve 3 36 only allows the liquid to flow in one direction; vent stop valve 37 controls the discharge of gas; ammonia tank safety valve 38 automatically releases the pressure when the pressure in the liquid ammonia tank 1 is too high; pressure gauge 3 39 displays the current pressure value; vehicle-mounted chiller 40 is used to cool the liquid in the system; liquid inlet and outlet air pressure regulating valve 41 maintains a constant pressure by adjusting the inflow and outflow of the liquid. The above is the return liquid control equipment after the liquid ammonia enters the high-pressure plunger pump 20.

[0051] This system changes the temperature and pressure through a series of heat exchangers (primary liquid inlet heat exchanger 10, secondary liquid inlet heat exchanger 15 and liquid return heat exchanger 29) and liquid ammonia pump 2 to finally reach the required conditions. At the same time, the system is also equipped with multiple safety valves (safety valve 7, ammonia rail safety valve 22, liquid return safety valve 26 and ammonia tank safety valve 38) and pressure gauges (pressure gauge 1 16, pressure gauge 2 24 and pressure gauge 3 39) and other devices to ensure the safety and accuracy of operation.

[0052] Specifically, the working process of the system can be divided into the following steps: liquid ammonia is extracted from the liquid ammonia tank 1 by the liquid ammonia pump 2. The extracted liquid ammonia passes through the check valve 4, the liquid and gas outlet stop valve 5 and the one-way valve 6 to ensure that the liquid can only flow in one direction. The liquid enters the first-level liquid inlet heat exchanger 10, where it will be cooled by heat exchange. After passing through the first-level liquid inlet heat exchanger 10, the liquid continues to flow to the airbag pulse damper 11 to reduce fluctuations in the flow. The temperature sensor 12 monitors the temperature of the liquid after passing through the first-level liquid inlet heat exchanger 10. The pressure sensor 13 monitors the overall pressure of the system. The one-way valve 14 again ensures that the liquid can only flow in one direction. The liquid enters the second-level liquid inlet heat exchanger 15, where it will be further cooled with the return liquid to maintain the liquid ammonia temperature and ensure the stability of the ammonia liquid supply. The 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 in the rail. The return ball valve 23 controls the flow of the return liquid. The return liquid passes through the pressure gauge 24 and the return liquid discharge stop valve 25, and can be discharged through these valves if necessary. The return liquid also passes through the return liquid safety valve 26 to prevent the return liquid pressure from being too high. The return liquid enters the return liquid heat exchanger 29, where it is cooled. The cooled liquid passes through the temperature sensor 4 30 to detect the temperature. The airbag pulse damper 2 31 reduces the fluctuations in the liquid flow again. The ball valve 1 32 controls the flow of the liquid. The electric control pressure regulating valve 33 adjusts the pressure of the liquid electronically. Another ball valve 2 34 controls the flow of the liquid. The mechanical back pressure valve 35 maintains a certain outlet pressure. The check valve 3 36 ensures that the liquid can only flow in one direction. The vent stop valve 37 controls the discharge of gas. The ammonia tank safety valve 38 automatically releases the pressure in the liquid ammonia tank 1 when the pressure is too high. The on-board chiller 40 is used to cool the liquid in the system. The inlet and outlet air pressure regulating valve 41 maintains a constant pressure by adjusting the inflow and outflow of liquid.

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

[0054] Liquid inlet pressure regulation: Use liquid ammonia pump 2 to supply low-pressure liquid ammonia, and use the pressure sensor 13 at the liquid supply outlet as feedback to control the pumping frequency of liquid ammonia pump 2 to achieve the purpose of controlling the liquid supply pressure through the ECU (Electronic Control Unit), also known as the driving computer or on-board computer, which is a microcomputer controller dedicated to the car.

[0055] Inlet liquid temperature control: Use the on-board chiller 40 to control the inlet liquid to perform two-stage heat exchange temperature control (primary inlet liquid heat exchanger 10 and secondary inlet liquid heat exchanger 15) to ensure that the ammonia supply is in liquid state. At the same time, cool the abnormal return liquid from the oil rail (return liquid heat exchanger 29) to prevent the liquid ammonia temperature from rising to form a gas-liquid mixed phase.

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

[0057] Return liquid pressure and temperature regulation: A set of pressure regulating device is installed at the return port of the gas cylinder: it is composed 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 temperature of the return liquid to ensure that the return liquid is in liquid state and to ensure the stability of the supply pressure and liquid phase.

[0058] Design for safety control and maintenance convenience: 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 failure caused by high temperature and equipment abnormality. 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, which can 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 comprises: 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 primary liquid inlet heat exchanger 10, the primary 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 a vehicle-mounted chiller 40, the vehicle-mounted chiller 40 is thermally coupled with the primary liquid inlet heat exchanger 10 and the liquid return heat exchanger 29.

[0060] The liquid ammonia pump 2 can control the low-pressure liquid ammonia entering the high-pressure plunger pump 20, and the liquid ammonia is pressurized by the plunger of the high-pressure plunger pump 20 to enter the high-pressure liquid ammonia rail 21, and then is injected into the combustion chamber by the liquid ammonia injector installed on the high-pressure liquid ammonia rail 21 to burn and do work. The direct injection method in the cylinder is adopted to optimize the combustion process, improve the combustion efficiency, and help reduce emissions. At the same time, with the cooperation of the first-level liquid inlet heat exchanger 10, the liquid return heat exchanger 29 and the on-board chiller 40, the first-level heat exchange temperature control is performed during the liquid inlet to ensure that the ammonia supply is liquid, and the liquid ammonia temperature is prevented from rising to form a gas-liquid mixed phase during the liquid return, providing the engine with a stable and reliable liquid ammonia supply and liquid return system, which has the advantages of outstanding reliability, controllable cost and simple structure, and avoids the ammonia premixed combustion method in the related technology, which has high nitrous oxide emissions under low load conditions and limits the increase of the ammonia blending ratio under high load conditions.

[0061] In conjunction with the second aspect, in one implementation, Figure 1 As shown, the vehicle-mounted high-pressure liquid ammonia supply and liquid return control system further includes: a secondary liquid inlet heat exchanger 15, which is installed on the liquid inlet pipeline and thermally coupled with 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. Exemplarily, the liquid cooled by the primary liquid inlet heat exchanger 10 enters the secondary liquid inlet heat exchanger 15, where it will be further cooled to maintain the liquid ammonia temperature and ensure the stability of the ammonia supply liquid phase.

[0062] In the description of the present application, it should be noted that the terms "upper", "lower", etc. 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 the present application 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 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 it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present 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 only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply 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 including 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, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0064] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A vehicle-mounted high-pressure liquid ammonia supply and liquid return 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 water chiller (40), the on-board water chiller (40) being thermally coupled to the primary 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), the 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), the 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), the 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 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: An airbag-type pulse damper (11), the airbag-type pulse damper (11) 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).

6. 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: The second airbag type 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 liquid 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 an 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 connected to the other end of the second ball valve (34).

8. 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: An ammonia rail safety valve (22), wherein the 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 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 discharge stop valve (25), the liquid return discharge stop valve (25) is installed in 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 as described in any one of claims 1 to 9.

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