A power system based on an ammonia fuel internal combustion engine and a control method thereof

Abstract

The present invention discloses a power system based on an ammonia fuel internal combustion engine and a control method thereof. The internal combustion engine uses hydrogen produced by online cracking of ammonia as ignition chamber fuel and ammonia as main combustion chamber fuel to achieve zero carbon emissions. Through a cooling circulation pipeline, the cooling system of the ammonia fuel internal combustion engine and the waste heat of the cracked gas after catalytic cracking of ammonia are used to vaporize liquid ammonia; the characteristics of liquid ammonia vaporization and expansion and the momentum of the internal combustion engine exhaust gas are respectively used to drive the turbine generator device to output electricity, and the electricity is stored in a battery; the heat of the exhaust gas and a ruthenium-based catalyst are used by the ammonia catalytic cracker to crack ammonia and produce hydrogen, and electric heating is used as heat supplement; a thermal insulation coating is provided on the internal combustion engine piston to reduce heat loss; different control methods are used for the variable intake and exhaust valves and fuel supply mode to cope with changes in the load conditions of the ammonia fuel internal combustion engine, thereby improving the thermal efficiency of ammonia; the present invention realizes the efficient utilization of the waste heat of the power system, and the combustion control method can be selected according to the load conditions, so that the ammonia fuel internal combustion engine can operate stably and efficiently.

Description

Technical Field

[0001] The present invention belongs to the technical field of efficient and clean utilization of ammonia fuel, and in particular relates to a power system based on an ammonia fuel internal combustion engine and a control method thereof. Background Art

[0002] With global warming and other environmental issues becoming increasingly severe, reducing greenhouse gas emissions like carbon dioxide and achieving a low-carbon energy structure have become development goals for countries around the world. The development of clean combustion technologies that can replace traditional fossil fuels is urgent. The power systems of vehicles and ships are a major source of carbon dioxide emissions, making the development of clean fuel power systems characterized by low and no carbon emissions a key area of focus.

[0003] Hydrogen, as an ideal renewable energy source, offers advantages such as being green and pollution-free. However, hydrogen typically requires a pressure exceeding 25 MPa when stored at room temperature. Consequently, hydrogen faces storage and transportation challenges, with cost and safety constraints hindering its application. Ammonia is another carbon-free fuel that can be stored in a liquid state at 0.857 MPa at 20°C, making it inexpensive to store and transport. Furthermore, compared to liquid hydrogen, liquid ammonia has a higher energy density, a higher octane rating, and improved anti-knock properties, offering safety advantages due to its low chemical reactivity. However, ammonia also presents challenges such as a low flame propagation velocity, high minimum ignition energy, and narrow flammability limits. Therefore, research into ammonia's ignition and combustion processes is necessary to meet the requirements for its application in power systems. Previous research has demonstrated that the use of a pre-chamber jet ignition system in ammonia-fueled internal combustion engines can efficiently ignite ammonia fuel and improve its combustion characteristics. There are several fuel options for the precombustion chamber. Hydrogen has been widely studied as a precombustion chamber fuel due to its low ignition energy, high laminar flame speed, and enhanced ammonia mixture activity. Furthermore, ammonia can be cracked to produce hydrogen under high temperature and the presence of a catalyst. At 500°C and using a ruthenium-based catalyst, the cracking efficiency of ammonia can reach over 90%. Therefore, hydrogen produced by catalytic cracking of ammonia is a promising precombustion chamber fuel. Existing solutions typically use low-pressure ammonia or high-pressure liquid ammonia as the main combustion chamber fuel for ammonia-fueled internal combustion engines. However, ammonia has a low energy density and a high latent heat of vaporization. The injection of large amounts of ammonia fuel significantly lowers the ambient temperature, making stable and efficient combustion difficult. Furthermore, approximately 35% of the energy released by combustion in ammonia-fueled internal combustion engines is discharged in the exhaust, resulting in significant energy loss. The overall energy utilization of ammonia-fueled powertrains still has significant room for improvement. Furthermore, to ensure stable operation of ammonia-fueled internal combustion engines under various operating conditions, appropriate control methods are required. Summary of the Invention

[0004] The purpose of the present invention is to provide a power system based on an ammonia fuel internal combustion engine and a control method thereof, so as to solve one or more technical problems existing in the prior art, and to improve the comprehensive energy utilization rate of the ammonia fuel power system while achieving stable ignition and efficient combustion of the ammonia fuel internal combustion engine.

[0005] To achieve the above objectives, the present invention adopts the following technical solution, which includes a liquid ammonia tank 1, characterized in that the output port of the liquid ammonia tank 1 is connected to the input port of the liquid ammonia filter 2 via a forty-first regulating valve 41, the output port of the liquid ammonia filter 2 is connected to one end of a forty-third regulating valve 43 and one end of a forty-second regulating valve 42, respectively, the other end of the forty-third regulating valve 43 is connected to the liquid ammonia inlet 53 of the liquid ammonia vaporization power generation device 10, the other end of the forty-second regulating valve 42 is connected to the input end of the high-pressure liquid ammonia pump 3, and the output end of the high-pressure liquid ammonia pump 3 is connected to the liquid ammonia injector 27;

[0006] The power output port of the liquid ammonia vaporization power generation device 10 is connected to the battery 11. The coolant outlet 52 of the liquid ammonia vaporization power generation device 10 is connected to the input port of the circulation pump 9. The ammonia outlet 55 of the liquid ammonia vaporization power generation device 10 is respectively connected to one end of the first ammonia pipeline P2 and one end of the second ammonia pipeline P3. The other end of the first ammonia pipeline P2 is connected to the inlet of the ammonia storage tank 6 via the forty-fifth regulating valve 45 and the one-way valve 5. The outlet of the ammonia storage tank 6 is connected to the ammonia injector 23 via the forty-ninth regulating valve 49 and the ammonia booster pump 8. The other end of the second ammonia pipeline P3 is connected to the ammonia inlet of the ammonia catalytic cracker 12. The second ammonia pipeline P3 is provided with a forty-fourth regulating valve 44.

[0007] The battery 11 is connected to the power output port of the exhaust gas turbine generator 18. The air inlet of the exhaust gas turbine generator 18 is connected to the outlet of the exhaust duct 30 via the exhaust gas pipeline P4. The air outlet of the exhaust gas turbine generator 18 is connected to the exhaust gas inlet of the ammonia catalytic cracker 12. The power port of the ammonia catalytic cracker 12 is connected to the battery 11. The cracked gas outlet of the ammonia catalytic cracker 12 is connected to the air inlet of the heat exchanger 15. The air outlet of the heat exchanger 15 is connected to the hydrogen injector 25 and one end of the forty-eighth regulating valve 48 respectively through the purifier 16 and the one-way valve 17.

[0008] The coolant output end of the circulation pump 9 is connected to the internal combustion engine cooling system 32 through the forty-sixth regulating valve 46, and is connected to the coolant input end of the heat exchanger 15 through the forty-seventh regulating valve 47. The coolant output end of the heat exchanger 15 is connected to the coolant input end of the liquid ammonia vaporization power generation device 10.

[0009] As a preferred embodiment, the liquid ammonia vaporization power generation device 10 of the present invention includes a shell, in which an inverted X-shaped coolant pipe is provided. Both ends of the coolant pipe pass through the shell, one end of the coolant pipe is a liquid ammonia inlet 53, and the other end of the coolant pipe is connected to the air inlet of the turbine generator 54, and the air outlet of the turbine generator 54 is an ammonia outlet 55; a coolant inlet 51 is provided on one side of the shell, and a coolant outlet 52 is provided on the other side of the shell.

[0010] As another preferred embodiment, the upper end of the main combustion chamber 22 of the present invention is provided with an intake duct 29, a pre-combustion chamber 21, a liquid ammonia injector 27, and an exhaust duct 30 in sequence from one side to the other side, an ammonia injector 23 is provided on the intake duct 29, a variable intake valve 24 is provided at the connection between the intake duct 29 and the main combustion chamber 22, the lower end outlet of the liquid ammonia injector 27 is connected to the interior of the main combustion chamber 22, a variable exhaust valve 28 is provided at the connection between the exhaust duct 30 and the main combustion chamber 22, and a thermal insulation coating 31 is provided in the main combustion chamber 22; the pre-combustion chamber 21 is provided at the upper end of the main combustion chamber 22, a hydrogen injector 25 and a spark plug 26 are provided at the upper end of the pre-combustion chamber 21, and the lower end outlet of the pre-combustion chamber 21 is connected to the interior of the main combustion chamber 22; the inlet of the ammonia injector 23 is connected to the outlet of the ammonia booster pump 8, the liquid inlet end of the liquid ammonia injector 27 is connected to the output end of the high-pressure liquid ammonia pump 3, and the outlet of the exhaust duct 30 is connected to the exhaust pipe P4.

[0011] As a preferred solution, a temperature sensor 13 is provided on the ammonia catalytic cracker 12 of the present invention.

[0012] As another preferred embodiment, the tail gas outlet of the ammonia catalytic cracker 12 of the present invention is connected to a tail gas purifier 14 .

[0013] As another preferred solution, the hydrogen storage tank 19 of the present invention is provided with a pressure detection port, which is connected to the pressure sensor 20 .

[0014] Secondly, the high-pressure liquid ammonia pump 3 of the present invention is provided with a flow sensor 57 and a pressure sensor 4 .

[0015] In addition, a pressure sensor 7 is provided on the ammonia storage tank 6 of the present invention.

[0016] Beneficial effects of the present invention:

[0017] The present invention uses a cooling circulation pipeline to supply waste heat from the internal combustion engine cooling system and the nitrogen-containing hydrogen gas after catalytic cracking of ammonia to the liquid ammonia vaporization process. A turbine generator is installed at the liquid ammonia vaporization device. The expansion characteristics of ammonia during the liquid ammonia vaporization process are used to drive the turbine to generate electricity, and the electricity is stored in a battery, thereby improving the working efficiency and power utilization rate of the turbine generator device. The momentum of the internal combustion engine exhaust gas is used to drive the turbine generator device to output electricity, and the electricity is stored in the battery. The ammonia catalytic cracker uses the heat of the internal combustion engine exhaust gas and a ruthenium-based catalyst to carry out the ammonia cracking reaction, and the battery is used for electrical heating to cope with changes in the internal combustion engine operating conditions. The ammonia generated by vaporizing liquid ammonia and the hydrogen generated by cracking ammonia are stored in an ammonia storage tank and a hydrogen storage tank respectively to meet different combustion control methods; a thermal insulation coating is provided to increase the temperature of the main combustion chamber to ensure stable combustion of the ammonia fuel; in the face of changes in the load conditions of the ammonia fuel internal combustion engine, the present invention adopts different control methods for the variable intake and exhaust valves and fuel supply methods, which greatly improves the thermal efficiency of ammonia and realizes stable operation of the internal combustion engine; the ammonia fuel internal combustion engine of the present invention not only realizes the efficient utilization of the waste heat of the power system, but also can select the combustion control method according to the load conditions to realize stable and efficient operation of the ammonia fuel internal combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.

[0019] Figure 1 The present invention is a schematic diagram of a power system based on an ammonia fuel internal combustion engine and a control method thereof.

[0020] Figure 2 It is a schematic diagram of the related structures of the main combustion chamber and pre-combustion chamber of the ammonia fuel internal combustion engine of the present invention.

[0021] Figure 3 It is a structural schematic diagram of the liquid ammonia vaporization power generation device of the present invention.

[0022] In the figure, 1-liquid ammonia tank, 2-liquid ammonia filter, 3-high-pressure liquid ammonia pump, 4-pressure sensor, 5-check valve, 6-ammonia storage tank, 7-pressure sensor, 8-ammonia booster pump, 9-circulation pump, 10-liquid ammonia vaporization power generation device, 11-battery, 12-ammonia catalytic cracker, 13-temperature sensor, 14-exhaust gas purifier, 15-heat exchanger, 16-purifier, 17-check valve, 18-exhaust gas turbine power generation device, 19-hydrogen storage tank, 20-pressure sensor, 21-precombustion chamber, 22-main combustion chamber, 23-ammonia Injector, 24-variable intake valve, 25-hydrogen injector, 26-spark plug, 27-liquid ammonia injector, 28-variable exhaust valve, 29-intake duct, 30-exhaust duct, 31-thermal insulation coating, 32-internal combustion engine cooling system, 41-50-regulating valve, P1-liquid ammonia pipeline, P2-first ammonia pipeline, P3-second ammonia pipeline, P4-exhaust pipeline, P5-coolant circulation pipeline, 51-coolant inlet, 52-coolant outlet, 53-liquid ammonia inlet, 55-ammonia outlet, 54-turbine generator, 56-electric wires. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 As shown, the present invention includes a liquid ammonia tank 1, a portion of the liquid ammonia is used for vaporization to produce ammonia gas, and a portion of the liquid ammonia is directly injected into the main combustion chamber as fuel;

[0025] The output port of the liquid ammonia tank 1 is connected to the input port of the liquid ammonia filter 2 through the forty-first regulating valve 41. The output port of the liquid ammonia filter 2 is respectively connected to one end of the forty-third regulating valve 43 and one end of the forty-second regulating valve 42. The other end of the forty-third regulating valve 43 is connected to the liquid ammonia input port of the liquid ammonia vaporization power generation device 10. The other end of the forty-second regulating valve 42 is connected to the input end of the high-pressure liquid ammonia pump 3. The output end of the high-pressure liquid ammonia pump 3 is connected to the liquid ammonia injector 27.

[0026] The cooling circulation pipeline P5 supplies the waste heat of the internal combustion engine cooling system 32 and the cracked gas after catalytic cracking of ammonia to the liquid ammonia vaporization power generation device 10;

[0027] The cooling circulation pipeline P5 includes a circulation pump 9, a forty-sixth regulating valve 46, a forty-seventh regulating valve 47, a heat exchanger 15, a liquid ammonia vaporization power generation device 10, and an internal combustion engine cooling system 32. The coolant exchanges heat with the ammonia cracking gas at the heat exchanger 15, and with the internal combustion engine waste heat at the internal combustion engine cooling system 32. The coolant output end of the circulation pump 9 is connected to the coolant input end of the internal combustion engine cooling system 32 via the forty-sixth regulating valve 46, and is connected to the coolant input end of the heat exchanger 15 via the forty-seventh regulating valve 47. The coolant output ends of the internal combustion engine cooling system 32 and the heat exchanger 15 are connected to the coolant input end of the liquid ammonia vaporization power generation device 10, and the coolant output end of the liquid ammonia vaporization power generation device 10 is connected to the coolant input end of the circulation pump 9.

[0028] The cooling circulation pipeline P5 can use water as the circulating medium.

[0029] The liquid ammonia vaporization power generation device 10 performs the process of vaporizing liquid ammonia and generating electricity through turbines. Part of the vaporized ammonia is stored in the ammonia storage tank 6 for standby use, and part is used for cracking in the ammonia catalytic cracker 12 to produce hydrogen.

[0030] The ammonia output port of the liquid ammonia vaporization power generation device 10 is connected to one end of the first ammonia pipeline P2 and one end of the second ammonia pipeline P3, respectively. The other end of the first ammonia pipeline P2 is connected to the inlet of the ammonia storage tank 6 via the forty-fifth regulating valve 45 and the one-way valve 5 in sequence. The outlet of the ammonia storage tank 6 is connected to the ammonia injector 23 via the forty-ninth regulating valve 49 and the ammonia booster pump 8 in sequence. The other end of the second ammonia pipeline P3 is connected to the ammonia inlet of the ammonia catalytic cracker 12. The second ammonia pipeline P3 is provided with a forty-fourth regulating valve 44. The power output port of the liquid ammonia vaporization power generation device 10 is connected to the battery 11.

[0031] The liquid ammonia vaporization power generation device 10 includes a shell, and an inverted "X"-shaped coolant pipe is provided in the shell. Both ends of the coolant pipe pass through the shell, one end of the coolant pipe is a liquid ammonia inlet 53, and the other end of the coolant pipe is connected to the air inlet of the turbine generator 54, and the air outlet of the turbine generator 54 is an ammonia outlet 55; a coolant inlet 51 is provided on one side of the shell, and a coolant outlet 52 is provided on the other side of the shell. The use of an inverted "X"-shaped coolant pipe can effectively extend the heat exchange time of liquid ammonia in the shell and improve the heat exchange efficiency and effect. The coolant inlet 51 and the coolant outlet 52 are provided on both sides of the shell to increase the heat exchange time of the coolant in the shell and improve the heat exchange efficiency and effect. The ammonia gas after the liquid ammonia vaporizes and expands acts on the turbine blades, driving the turbine to generate electricity, and the generated electricity is passed into the battery 11;

[0032] The liquid ammonia vaporization power generation device 10 can also adopt a thermoelectric power generation device structure, using the liquid ammonia vaporization heat absorption process as a cold source and the coolant in the circulation pipeline P5 as a heat source. A semiconductor thermoelectric power generation sheet is provided at the location where the coolant and liquid ammonia exchange heat. Under the action of the temperature difference between the cold source and the heat source, electricity is generated and passed into the battery 11.

[0033] The electricity stored in the battery 11 can be used to supply power to other components of the vehicle.

[0034] The exhaust gas from the ammonia fueled internal combustion engine is used to generate electricity from the turbine and to heat the ammonia catalytic cracker 12;

[0035] The outlet of the exhaust passage 30 is connected to the air inlet of the exhaust gas turbine generator 18 via the exhaust gas pipeline P4. The power output port of the exhaust gas turbine generator 18 is connected to the battery 11. The air outlet of the exhaust gas turbine generator 18 is connected to the exhaust gas inlet of the ammonia catalytic cracker 12. The exhaust gas of the ammonia catalytic cracker 12 is purified by the exhaust gas purifier 14 and then discharged into the air. The electric heater of the ammonia catalytic cracker 12 is connected to the battery 11.

[0036] After being purified by the purifier 16, a portion of the cracked gas is stored in the hydrogen storage tank 19 for standby use, and a portion is directly introduced into the pre-combustion chamber 21 for combustion. The outlet of the ammonia catalytic cracker 12 is connected to the inlet of the heat exchanger 15. The outlet of the heat exchanger 15 is connected, in sequence, through the purifier 16 and the one-way valve 17 to the inlet of the hydrogen injector 25 and one end of the 48th regulating valve 48. The other end of the 48th regulating valve 48 is connected to the inlet of the hydrogen storage tank 19. The outlet of the hydrogen storage tank 19 is connected to one end of the 50th regulating valve 50. The other end of the 50th regulating valve 50 is connected to the inlet of the hydrogen injector 25.

[0037] The pre-combustion chamber 21 is arranged on the cylinder head, and a hydrogen injector 25 and a spark plug 26 are provided at the upper end thereof; an intake duct 29, a pre-combustion chamber 21, a liquid ammonia injector 27, and an exhaust duct 30 are provided at the upper end of the main combustion chamber 22 in sequence from one side to the other, and an ammonia injector 23 is provided on the intake duct 29; a variable intake valve 24 is provided at the connection between the intake duct 29 and the main combustion chamber 22, and the lower end outlet of the liquid ammonia injector 27 is connected to the interior of the main combustion chamber 22, and a variable exhaust valve 28 is provided at the connection between the exhaust duct 30 and the main combustion chamber 22, which improves the combustion of ammonia by controlling the face value and scavenging degree when the variable intake and exhaust valves are opened; a thermal insulation coating 31 is provided in the main combustion chamber 22, and the thermal insulation coating 31 is provided on the piston, firstly, to reduce the heat of the piston, ensure its working reliability and extend its service life; secondly, to reduce the heat loss in the cylinder, to meet the heat demand of liquid ammonia vaporization to a certain extent, and to ensure the stable combustion of ammonia; thirdly, to increase the exhaust temperature, which is conducive to the heat recovery and utilization of the exhaust gas.

[0038] The present invention proposes a combustion strategy that combines pre-chamber jet ignition with direct injection of liquid ammonia into the cylinder to achieve diffusion combustion of liquid ammonia, and solves the cold start problem of the ammonia fuel internal combustion engine by setting up ammonia and hydrogen storage tanks, reducing the complexity of the fuel supply system, ensuring the singleness of the fuel carried by the whole vehicle and the convenience of filling, while achieving stable operation of the ammonia fuel internal combustion engine.

[0039] The ammonia catalytic cracker 12 is equipped with a temperature sensor 13. The temperature sensor 13 monitors the reaction temperature within the ammonia catalytic cracker 12 in real time. The temperature sensor 13 transmits a temperature signal from the catalytic cracker 12. When the temperature in the catalytic cracker 12 does not reach 500°C, the temperature sensor 13 can be configured to control the battery 11 to power the heater in the catalytic cracker 12, providing the energy required for the ammonia cracking reaction in the catalytic cracker 12. This process primarily operates during the startup and idling conditions of an ammonia-fueled internal combustion engine.

[0040] The hydrogen storage tank 19 is provided with a pressure detection port, which is connected to the pressure sensor 20; the pressure sensor 20 can be connected to the detection signal input port of the 48th regulating valve 48 and the detection signal input port of the 50th regulating valve 50; the pressure sensor 20 can monitor the pressure value in the hydrogen storage tank in real time to control the opening and closing of the 48th regulating valve 48 and the 50th regulating valve 50.

[0041] The ammonia storage tank 6 is provided with a pressure detection port, which is connected to the pressure sensor 7; the detection signal output port of the pressure sensor 7 can be connected to the detection signal input port of the forty-fifth regulating valve 45 and the detection signal input port of the forty-ninth regulating valve 49; the pressure sensor 7 can monitor the pressure value in the ammonia storage tank in real time to control the opening and closing of the forty-fifth regulating valve 45 and the forty-ninth regulating valve 49, and the one-way valve 5 prevents the backflow of ammonia.

[0042] The high-pressure liquid ammonia pump 3 is equipped with a flow sensor 57 and a pressure sensor 4. The detection signal output port of the pressure sensor 4 can be connected to the detection signal input port of the controller of the high-pressure liquid ammonia pump 3 to ensure that the liquid ammonia reaches the required pressure. The detection signal output port of the flow sensor 57 can be connected to the detection signal input ports of the controllers of the 42nd regulating valve 42 and the 43rd regulating valve 43 to adjust the flow rates of the two pipelines.

[0043] When the internal combustion engine is running stably, the forty-fifth regulating valve 45 and the forty-eighth regulating valve 48 are opened, the forty-ninth regulating valve 49 and the fiftieth regulating valve 50 are closed, and ammonia and hydrogen enter the ammonia storage tank 6 and the hydrogen storage tank 19 through the regulating valves 45 and 48 respectively. After the pressure of the storage tank reaches the rated value, the forty-fifth regulating valve 45 and the forty-eighth regulating valve 48 are closed, and the ammonia and hydrogen stored in the storage tanks are used as fuel during the startup condition of the internal combustion engine.

[0044] During the startup condition, the 50th regulating valve 50 and the 49th regulating valve 49 are opened, the 48th regulating valve 48 and the 45th regulating valve 45 are closed, and the hydrogen storage tank 19 and the ammonia storage tank 6 provide hydrogen and ammonia to the pre-combustion chamber 21 and the main combustion chamber 22 respectively.

[0045] The combustion control method comprises the following steps:

[0046] During the starting operation, during the intake stroke, ammonia in the ammonia storage tank 6 enters the intake passage through the ammonia injector 23, and the piston is located between 360° and 180° before the top dead center. The ammonia injector (23) injects ammonia, which is mixed with air and enters the main combustion chamber 22; the opening face value of the variable intake valve 24 is increased to increase the intake volume so that the ammonia / air mixture can fully enter the cylinder, and the nitrogen-containing hydrogen in the hydrogen storage tank 19 enters the pre-combustion chamber 21 through the hydrogen injector 25; during the compression stroke, the piston is located between 40° and 20° before the top dead center, and the spark plug 26 ignites the hydrogen mixture in the pre-combustion chamber 21. The flame or jet product enters the main combustion chamber 22 through the through hole to ignite the ammonia mixture; during the exhaust stroke, the opening of the variable exhaust valve 28 is delayed to quickly increase the temperature in the cylinder.

[0047] During low and medium load conditions, during the intake stroke, when the piston is between 300° and 180° before top dead center (TBDC), liquid ammonia, after being pressurized by the high-pressure liquid ammonia pump 3, is directly injected into the cylinder through the liquid ammonia injector 27. The injection advance angle is increased, and the variable intake valve 24 is opened in advance. At the same time, the opening value of the variable intake valve is reduced to enhance the intake vortex intensity and promote the formation of a homogeneous premixed gas in the cylinder. The cracked gas produced by the ammonia catalytic cracking unit 12 is purified by the purifier 16, and the nitrogen-containing hydrogen enters the precombustion chamber through the hydrogen injector 25. During the compression stroke, when the piston is between 40° and 20° before top dead center (TBDC), the spark plug 26 ignites the hydrogen mixture in the precombustion chamber 21. The flame or jet products enter the main combustion chamber 22 through the through hole and ignite the ammonia mixture. During the exhaust stroke, the scavenging degree of the variable exhaust valve 28 is increased to prevent excessive pressure in the cylinder.

[0048] Under high-load conditions, during the intake stroke, liquid ammonia is pressurized by the high-pressure liquid ammonia pump 3 and then directly injected into the cylinder through the liquid ammonia injector 27. When the piston is between 260° and 180° before the top dead center, the liquid ammonia injector 27 injects an appropriate amount of liquid ammonia in advance for the first time, reducing the face value when the variable intake valve 24 is opened, forming a homogeneous ammonia / air premixed gas in the cylinder. The cracked gas generated by the ammonia catalytic cracking unit 12 is purified by the purifier 16, and the nitrogen-containing hydrogen enters the pre-combustion chamber through the hydrogen injector 25. 21. During the compression stroke, the piston is located between 60° and 40° before top dead center, the spark plug 26 ignites the hydrogen mixture in the pre-combustion chamber 21, and the flame or jet product enters the main combustion chamber 22 through the through hole to ignite the ammonia mixture. The piston is located between 30° and 10° before top dead center, and the liquid ammonia injector 27 injects a sufficient amount of liquid ammonia for the second time to achieve diffusion combustion of liquid ammonia and improve the power of the ammonia fuel internal combustion engine; during the exhaust stroke, the scavenging degree of the variable exhaust valve 28 is increased to prevent the pressure in the cylinder from being too high.

[0049] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the implementation examples of the present invention. Ordinary technicians in this field should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present invention.

Claims

1. A power system based on an ammonia fuel internal combustion engine, characterized in that: include: A liquid ammonia tank (1), wherein the output port of the liquid ammonia tank (1) is connected to the input port of the liquid ammonia filter (2) via a forty-first regulating valve (41), the output port of the liquid ammonia filter (2) is respectively connected to one end of the forty-third regulating valve (43) and one end of the forty-second regulating valve (42), the other end of the forty-third regulating valve (43) is connected to the liquid ammonia inlet (53) of the liquid ammonia vaporization power generation device (10), the other end of the forty-second regulating valve (42) is connected to the input end of the high-pressure liquid ammonia pump (3), and the output end of the high-pressure liquid ammonia pump (3) is connected to the liquid ammonia injector (27); A cooling circulation pipeline (P5) comprises a circulation pump (9), a forty-sixth regulating valve (46), a forty-seventh regulating valve (47), an internal combustion engine cooling system (32), a heat exchanger (15), and a liquid ammonia vaporization power generation device (10), wherein the coolant output end of the circulation pump (9) is connected to the internal combustion engine cooling system (32) via the forty-sixth regulating valve (46), and is connected to the coolant input end of the heat exchanger (15) via the forty-seventh regulating valve (47), the coolant inlet (51) of the liquid ammonia vaporization power generation device (10) is connected to the coolant output end of the heat exchanger (15) and the coolant output end of the internal combustion engine cooling system (32), and the coolant outlet (52) of the liquid ammonia vaporization power generation device (10) is connected to the coolant input end of the circulation pump (9); A liquid ammonia vaporization power generation device (10), wherein the power output port of the liquid ammonia vaporization power generation device (10) is connected to the battery (11), the ammonia output port (55) of the liquid ammonia vaporization power generation device (10) is respectively connected to one end of the first ammonia pipeline (P2) and one end of the second ammonia pipeline (P3), the other end of the first ammonia pipeline (P2) is connected to the inlet of the ammonia storage tank (6) through the forty-fifth regulating valve (45) and the one-way valve (5), the outlet of the ammonia storage tank (6) is connected to the ammonia injector (23) through the forty-ninth regulating valve (49) and the ammonia booster pump (8), the other end of the second ammonia pipeline (P3) is connected to the ammonia inlet of the ammonia catalytic cracker (12), and the second ammonia pipeline (P3) is provided with a forty-fourth regulating valve (44); An exhaust gas turbine generator device (18) has an air inlet connected to the outlet of the exhaust duct (30) via an exhaust gas pipeline (P4), an air outlet of the exhaust gas turbine generator device (18) is connected to the exhaust gas inlet of the ammonia catalytic cracker (12), and an electric energy output port of the exhaust gas turbine generator device (18) is connected to the battery (11).

2. The power system based on an ammonia fuel internal combustion engine according to claim 1, characterized in that: The electric heater of the ammonia catalytic cracker (12) is connected to the battery (11), the cracked gas outlet of the ammonia catalytic cracker (12) is connected to the air inlet of the heat exchanger (15), the air outlet of the heat exchanger (15) is connected to the hydrogen injector (25) and one end of the forty-eighth regulating valve (48) respectively through the purifier (16) and the one-way valve (17), the other end of the forty-eighth regulating valve (48) is connected to the air inlet of the hydrogen storage tank (19), and the air outlet of the hydrogen storage tank (19) is connected to the hydrogen injector (25) through the fiftieth regulating valve (50).

3. The power system based on an ammonia fuel internal combustion engine according to claim 1, characterized in that: The liquid ammonia vaporization power generation device (10) comprises a shell, wherein an inverted "X"-shaped coolant pipe is provided in the shell, and both ends of the coolant pipe pass through the shell, one end of the coolant pipe is a liquid ammonia inlet (53), and the other end of the coolant pipe is connected to the air inlet of the turbine generator (54), and the air outlet of the turbine generator (54) is an ammonia output port (55). A coolant inlet (51) is provided on one side of the shell, and a coolant outlet (52) is provided on the other side of the shell.

4. The power system based on an ammonia fuel internal combustion engine according to claim 1, characterized in that: An intake duct (29), a pre-combustion chamber (21), a liquid ammonia injector (27), and an exhaust duct (30) are sequentially arranged at the upper end of the main combustion chamber (22) from one side to the other side. An ammonia injector (23) is arranged on the intake duct (29). A variable intake valve (24) is arranged at the connection between the intake duct (29) and the main combustion chamber (22). The lower end outlet of the liquid ammonia injector (27) is communicated with the interior of the main combustion chamber (22). A variable exhaust valve (28) is arranged at the connection between the exhaust duct (30) and the main combustion chamber (22). A heat insulation coating (31) is arranged on the piston. The pre-combustion chamber (21) is arranged on the cylinder head. A hydrogen injector (25) and a spark plug (26) are arranged at the upper end of the pre-combustion chamber (21). The lower end outlet of the pre-combustion chamber (21) is communicated with the interior of the main combustion chamber (22).

5. The power system based on an ammonia fuel internal combustion engine according to claim 2, characterized in that: The hydrogen storage tank (19) and the ammonia storage tank (6) are respectively provided with a pressure sensor (20) and a pressure sensor (7).

6. The power system based on an ammonia fuel internal combustion engine according to claim 1, characterized in that: The high-pressure liquid ammonia pump (3) is provided with a flow sensor (57) and a pressure sensor (4).

7. A control method for an ammonia fuel internal combustion engine, characterized in that: The steps include: During the starting operation, during the intake stroke, ammonia from the ammonia storage tank (6) enters the intake passage through the ammonia injector (23), is mixed with air, and then enters the main combustion chamber (22), increasing the opening face value of the variable intake valve (24). Nitrogen-containing hydrogen from the hydrogen storage tank (19) enters the pre-combustion chamber (21) through the hydrogen injector (25). During the compression stroke, the spark plug (26) ignites the hydrogen mixture in the pre-combustion chamber (21), and the flame or jet product enters the main combustion chamber (22) through the through hole to ignite the ammonia mixture. During the exhaust stroke, the opening of the variable exhaust valve (28) is delayed. Under low and medium load conditions, during the intake stroke, liquid ammonia is pressurized by the high-pressure liquid ammonia pump (3) and then directly injected into the cylinder through the liquid ammonia injector (27), and the injection advance angle is increased and the variable intake valve (24) is opened in advance, while the face value of the variable intake valve opening is reduced. The cracked gas generated by the ammonia catalytic cracking device (12) is purified by the purifier (16), and the nitrogen-containing hydrogen enters the pre-combustion chamber (21) through the hydrogen injector (25). During the compression stroke, the spark plug (26) ignites the hydrogen mixture in the pre-combustion chamber (21), and the flame or jet product enters the main combustion chamber (22) through the through hole to ignite the ammonia mixture. During the exhaust stroke, the scavenging degree of the variable exhaust valve (28) is increased; Under high-load conditions, during the intake stroke, liquid ammonia is pressurized by the high-pressure liquid ammonia pump (3) and then directly injected into the cylinder through the liquid ammonia injector (27). The liquid ammonia injector (27) injects an appropriate amount of liquid ammonia in advance for the first time to reduce the face value when the variable intake valve (24) is opened. The cracked gas generated by the ammonia catalytic cracking device (12) is purified by the purifier (16), and the nitrogen-containing hydrogen enters the pre-combustion chamber (21) through the hydrogen injector (25). During the compression stroke, the spark plug (26) ignites the hydrogen mixture in the pre-combustion chamber (21), and the flame or jet product enters the main combustion chamber (22) through the through hole to ignite the ammonia mixture. The liquid ammonia injector (27) injects a sufficient amount of liquid ammonia for the second time. During the exhaust stroke, the scavenging degree of the variable exhaust valve (28) is increased.

8. The control method of an ammonia fuel internal combustion engine according to claim 7, characterized in that: During the intake stroke of the starting condition, the piston is located between 360° and 180° before top dead center, and the ammonia injector (23) injects ammonia. During the compression stroke, the piston is located between 40° and 20° before top dead center, and the spark plug (26) ignites the hydrogen mixture in the pre-combustion chamber (21).

9. The control method of an ammonia fuel internal combustion engine according to claim 7, characterized in that: During the intake stroke of the medium and low load working conditions, the piston is located between 300° and 180° before the top dead center, and the liquid ammonia injector (27) injects liquid ammonia. During the compression stroke, the piston is located between 40° and 20° before the top dead center, and the spark plug (26) ignites the hydrogen mixture in the pre-combustion chamber (21).

10. The control method of an ammonia fuel internal combustion engine according to claim 7, characterized in that: During the intake stroke of the high-load working condition, the piston is located between 260° and 180° before the top dead center, and the liquid ammonia injector (27) injects liquid ammonia for the first time. During the compression stroke, the piston is located between 60° and 40° before the top dead center, the spark plug (26) ignites the hydrogen mixture in the pre-combustion chamber (21), and the piston is located between 30° and 10° before the top dead center, and the liquid ammonia injector (27) injects liquid ammonia for the second time.

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