A heavy-duty equipment-based ammonia-hydrogen, internal combustion engine, and fuel cell hybrid system and its efficient control method

Abstract

The present invention discloses an ammonia-hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and an efficient control method thereof. The present invention controls the total amount of hydrogen entering the internal combustion engine and the fuel cell to be a constant value, and achieves power output within a certain range of the hydrogen input amount by regulating the hydrogen distribution ratio entering the fuel cell; since the efficiency of the fuel cell is higher than that of the internal combustion engine, the proportion allocated to the internal combustion engine can be limited within a lower operating load range, thereby using part of the power in exchange for efficiency improvement. This technical solution can also effectively reduce the final remaining power of the battery and reduce some of the demand for the battery; the efficient control method of the present invention improves the response speed and energy efficiency of the hybrid power generation system, reduces the demand for the battery's storage capacity and the amount of ammonia carried by heavy-duty equipment, reduces economic costs, and is conducive to reducing valve changes and improving the overall operating life of the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of hybrid power, and in particular relates to an ammonia-hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and an efficient control method thereof. Background Art

[0002] Heavy-duty equipment is subject to high frequency and large amplitude load fluctuations during operation, posing certain challenges to the power unit selected for its operation. These power units must possess high load output power, a wide output power range, fast load response, easy fuel portability, storage, and transportation, and simple control methods.

[0003] As a traditional power plant, the internal combustion engine has a long history of development and is widely used for its mature technology, rapid energy conversion, low cost, and high output power. As an emerging power plant, the proton exchange membrane fuel cell (PEMFC) utilizes a chemical reaction to convert hydrogen into electricity, surpassing the Carnot efficiency of traditional thermal power plants. It boasts high power generation efficiency and zero emissions. Furthermore, both are compact, allowing them to be integrated into heavy-duty equipment to form a hybrid power system, effectively leveraging their complementary strengths to improve efficiency when meeting the load requirements of high-power heavy-duty equipment.

[0004] Because the internal combustion engine generates high-temperature flue gas during operation, and the internal mechanical structure requires cooling water for cooling, and the proton exchange membrane fuel cell also requires cooling water during operation, two cooling water heat dissipation loops are formed between the internal combustion engine and the fuel cell, as well as a high-temperature flue gas heat source. By rationally utilizing these three waste heat resources, the hybrid system can effectively save fuel and improve its operating efficiency.

[0005] Both internal combustion engines and proton exchange membrane fuel cell hybrid systems used in heavy-duty equipment use hydrogen as their energy source, a clean and high-calorific value. However, the production, transportation, storage, and transport of hydrogen are currently costly, making its direct use on heavy-duty equipment difficult. Ammonia, on the other hand, has relatively mature technologies for production, transportation, storage, and transport. Furthermore, ammonia contains no carbon, making its production pollution-free. For these reasons, a hybrid power generation system based on ammonia-hydrogen-internal combustion engine-fuel cell system has been developed for heavy-duty equipment.

[0006] At present, the hybrid system mainly uses dynamic programming algorithm and Pontryagin minimum principle to achieve power following. Although this method can optimize the system's working efficiency, it takes a certain amount of time to solve in each time step, which reduces the response speed of the hybrid system. In addition, this algorithm is essentially a process of distributing fuel to the power unit according to load demand. The system involves two variables: the total amount of hydrogen entering the fuel cell and the internal combustion engine, and the amount distributed to the fuel cell. A large number of valves need to be controlled, which is prone to control errors and control lags.

[0007] By controlling the total amount of hydrogen fed to the fuel cell and internal combustion engine to a constant value, the hybrid system can be directly controlled, improving its responsiveness. The system's output power is related to the total amount of hydrogen fed to the internal combustion engine and fuel cell, as well as the proportion allocated to the fuel cell. However, a power-following strategy with a constant total amount of hydrogen fed can easily lead to power generation surpluses while also increasing material usage. This poses challenges for both ammonia storage equipment and power storage systems in heavy-duty equipment, necessitating further improvements. Summary of the Invention

[0008] The present invention provides an ammonia-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and its efficient control method, which can solve the power generation system design problems encountered in heavy-duty equipment, and improve the response speed and energy efficiency of the hybrid power generation system through the control method, thereby reducing the demand for battery storage capacity and the problem of ammonia carrying capacity of heavy-duty equipment.

[0009] To solve the above problems, the present invention provides the following technical solutions:

[0010] An embodiment of the present invention provides an ammonia hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment, comprising an ammonia storage tank (1), a pressure reducing valve (2), an ammonia regulating distribution valve (3), a multi-stream heat exchanger (4), a plate heat exchanger (5), an air-cooled heat exchanger (6), an internal combustion engine tail gas treatment device (7), an ammonia catalytic cracker (8), a hydrogen burner (9), a burner hydrogen inlet distribution regulating valve (10), a power unit hydrogen inlet distribution regulating valve (11), a hydrogen-nitrogen gas separator (12), an ammonia-hydrogen internal combustion engine unit (13), a hydrogen fuel cell device (14), a fuel cell output current converter (15), an internal combustion engine output current converter (16), a circuit merging device (17), a battery (18), a battery current converter (19) and heavy-duty equipment (20);

[0011] The output end of the ammonia storage tank (1) is connected to a first pipeline (21), and a pressure reducing valve (2) and an ammonia regulating distribution valve (3) are provided on the first pipeline (21); one distribution outlet of the ammonia regulating distribution valve (3) is connected to a multi-stream heat exchanger (4) through a second pipeline (22), and another distribution outlet of the ammonia regulating distribution valve (3) is connected to an ammonia-hydrogen internal combustion engine unit (13) through a third pipeline (23); the multi-stream heat exchanger (4) is connected to a plate heat exchanger (5) through a fourth pipeline (24), and the plate heat exchanger (5) is connected to an ammonia catalytic cracker (8) through a fifth pipeline (25);

[0012] The multi-stream heat exchanger (4) is connected to the air-cooled heat exchanger (6) via a sixth pipeline (26) and a ninth pipeline (29); the air-cooled heat exchanger (6) is connected to the hydrogen fuel cell device (14) via a seventh pipeline (27); the hydrogen fuel cell device (14) is connected to the multi-stream heat exchanger (4) via an eighth pipeline (28); the air-cooled heat exchanger (6) is connected to the ammonia-hydrogen internal combustion engine unit (13) via a tenth pipeline (30); the ammonia-hydrogen internal combustion engine unit (13) is connected to the hydrogen fuel cell device (14) via an eighth pipeline (28); The eleventh pipeline (31) is connected to the multi-stream heat exchanger (4); the ammonia-hydrogen internal combustion engine unit (13) is connected to the ammonia catalytic cracker (8) via the twelfth pipeline (32); the ammonia catalytic cracker (8) is connected to the internal combustion engine exhaust gas treatment device (7) via the thirteenth pipeline (33); the ammonia catalytic cracker (8) is connected to the plate heat exchanger (5) via the fourteenth pipeline (34); the plate heat exchanger (5) is connected to the hydrogen-nitrogen gas separator (12) via the fifteenth pipeline (35);

[0013] One output end of the hydrogen-nitrogen gas separator (12) is connected to a sixteenth pipeline (36), which serves as a nitrogen output pipe; the other output end of the hydrogen-nitrogen gas separator (12) is connected to an ammonia-hydrogen internal combustion engine unit (13) via a seventeenth pipeline (37); a burner hydrogen inlet distribution regulating valve (10) and a power unit hydrogen inlet distribution regulating valve (11) are provided on the seventeenth pipeline (37); the burner hydrogen inlet distribution regulating valve (10) is connected to a hydrogen burner (9) via an eighteenth pipeline (38); the power unit hydrogen inlet distribution regulating valve (11) is connected to a hydrogen fuel cell device (14) via a nineteenth pipeline (39); and the hydrogen burner (9) is connected to an ammonia catalytic cracker (8) via a twentieth pipeline (40);

[0014] The ammonia hydrogen internal combustion engine unit (13) is electrically connected to the internal combustion engine output current converter (16) via a first circuit (41), the hydrogen fuel cell device (14) is electrically connected to the fuel cell output current converter (15) via a second circuit (42), the fuel cell output current converter (15) and the internal combustion engine output current converter (16) are electrically connected to a circuit merging device (17), the circuit merging device (17) is electrically connected to a battery current converter (19) and a heavy-load equipment (20) via a third circuit (43), and the battery current converter (19) is electrically connected to a battery (18) via a fourth circuit (44).

[0015] According to an optional embodiment of the present invention, the ammonia storage tank (1) is used to store liquid ammonia and is the energy source of the entire system; the multi-stream heat exchanger (4) is a device used to recycle the internal combustion engine cylinder jacket water and fuel cell cooling water in the system to preheat low-temperature ammonia; the plate heat exchanger (5) is a device used to perform secondary preheating of the hydrogen-ammonia mixed gas to the ammonia gas; and the air-cooled heat exchanger (6) is a heat exchange device used to reduce the excess temperature of the internal combustion engine cylinder jacket water and fuel cell cooling water to a set temperature.

[0016] According to an optional embodiment of the present invention, the internal combustion engine exhaust gas treatment device (7) is used to remove nitrogen oxides generated in the internal combustion engine exhaust gas; the catalytic cracker (8) is used to decompose ammonia into hydrogen to provide fuel for the fuel cell, the internal combustion engine and the burner, and also includes a device for exchanging heat with the internal combustion engine exhaust gas to recover part of the heat of the internal combustion engine exhaust gas; the hydrogen burner (9) provides heat for the catalytic device to enable the catalytic process to proceed smoothly; the burner hydrogen inlet regulating distribution valve (10) is used to distribute the hydrogen required for partial combustion to the burner; the power unit hydrogen inlet distribution regulating valve (11) is used to distribute hydrogen to the internal combustion engine and the fuel cell; the hydrogen-nitrogen gas separator (12) is used to separate nitrogen and reduce the nitrogen distributed to the combustion device and the power unit, thereby reducing the generated nitrogen oxides and improving the energy conversion efficiency of the system.

[0017] According to an optional embodiment of the present invention, the ammonia-hydrogen internal combustion engine unit (13) and the hydrogen fuel cell device (14) are the main power units of the system. The generated current passes through the fuel cell output current converter (15) and the internal combustion engine output current converter (16), and is then integrated by the circuit merging device (17) to provide power for the heavy-load equipment (20); and when the power is insufficient or excessive, it is supplemented or stored by the battery (18).

[0018] The embodiment of the present invention further provides an efficient control method for ammonia-to-hydrogen, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment, the efficient control method comprising:

[0019] Step S1: Under the load condition that meets the requirements of the entire heavy-duty equipment process, the amount of hydrogen entering the internal combustion engine and the fuel cell is controlled to be constant, and a certain efficiency lower limit is set to ensure that the output efficiency of the system is always in the high-efficiency range during operation, thereby determining the output range;

[0020] Step S2, then adjusting the distribution ratio of hydrogen entering the fuel cell to achieve power output within a certain range of the hydrogen intake;

[0021] Step S3: When the load power is less than the power output range, the system output is at the minimum power output, and the excess power is provided to the battery for storage; when the load power is greater than the power output range, the system output is at the maximum power output, and the insufficient power is provided by the battery.

[0022] According to an optional embodiment of the present invention, in step S1, when the total amount of hydrogen entering the internal combustion engine and the fuel cell is a constant value, as the distribution ratio of hydrogen entering the fuel cell increases, the output power of the system decreases, and the distribution ratio of one fuel cell corresponds to one output power of the system.

[0023] According to an optional embodiment of the present invention, step S3 includes: step S31, when the load power is less than the power output range, determining the state of charge (SOC) of the battery; if the state of charge (SOC) of the battery does not exceed a set upper threshold, the system output is output at the minimum power, and excess power is provided to the battery for storage; if the SOC of the battery exceeds the set upper threshold, the system stops operating, and the load is entirely provided by the battery;

[0024] According to an optional embodiment of the present invention, step S3 also includes: step S32, if the SOC of the battery is not lower than the set lower threshold value, the system output is based on the maximum power output, and the insufficient power is provided by the battery; if the battery state of charge is lower than the set lower threshold value, the lower limit of the power is modified to increase the output power range of the system to supplement part of the battery power.

[0025] Beneficial Effects: The embodiments of the present invention provide a hybrid system for producing hydrogen from ammonia, an internal combustion engine, and a fuel cell based on heavy-duty equipment, and an efficient control method thereof. The present invention controls the total amount of hydrogen entering the internal combustion engine and the fuel cell to a constant value, and by adjusting the hydrogen distribution ratio entering the fuel cell, achieves power output within a certain range of the hydrogen input amount. This method can effectively reduce the number of valves to be controlled. The only active control valves in the entire system are the distribution ratio valves leading to the internal combustion engine and the fuel cell. This method can quickly respond to the operating conditions of the heavy-duty equipment and can solve the characteristics of the current power following algorithm for hydrogen distribution of the power unit, such as long response time of the transport process and a large number of active control valves. Because the efficiency of the fuel cell is higher than that of the internal combustion engine, the proportion allocated to the internal combustion engine can be limited in the lower operating load range, thereby exchanging part of the power for efficiency improvement. This technical solution can also effectively reduce the final remaining power of the battery and reduce some of the demand on the battery. Compared with the current power following algorithm to achieve power following of heavy-duty equipment, the present invention can effectively improve the response speed of the hybrid system, reduce the number of active control valves, and meet the requirements of heavy-duty equipment operation. At the same time, the present invention is optimized on the basis of existing technical solutions, which can effectively reduce the capacity required by the battery and the weight of ammonia carried by heavy-duty equipment, reduce economic costs, and at the same time help reduce valve changes and improve the overall operating life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A working principle diagram of an ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application.

[0028] Figure 2 A power-efficiency relationship diagram for a constant total amount of hydrogen input for a heavy-duty ammonia-to-hydrogen, internal combustion engine, and fuel cell hybrid system provided in an embodiment of the present application.

[0029] Figure 3 A power-fuel cell distribution ratio relationship diagram for a constant total hydrogen input of an ammonia-hydrogen production system, an internal combustion engine, and a fuel cell hybrid system based on heavy-duty equipment is provided in an embodiment of the present application.

[0030] Figure 4 A flow chart of an efficient control method for an ammonia-to-hydrogen, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application.

[0031] Figure 5 A power and efficiency relationship diagram of an efficient control method for an ammonia-to-hydrogen, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described 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 those skilled in the art without making creative efforts are within the scope of protection of this application.

[0033] The present invention provides an ammonia-hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and an efficient control method thereof, which relates to the field of hydrogen energy development and utilization and energy management of complex systems. Under known working conditions, by adopting a method of regulating the total amount of hydrogen input of the power system to be constant and keeping the system operating in a high-efficiency range, while taking into account the SOC charge state of the battery, the overall system efficiency, the overall system response speed and the battery service life are effectively improved, the battery storage capacity requirement is reduced, and the system ammonia consumption and economic cost are reduced.

[0034] like Figure 1 As shown, an ammonia hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment includes an ammonia storage tank 1, a pressure reducing valve 2, an ammonia regulating distribution valve 3, a multi-stream heat exchanger 4, a plate heat exchanger 5, an air-cooled heat exchanger 6, an internal combustion engine exhaust gas treatment device 7, an ammonia catalytic cracker 8, a hydrogen burner 9, a burner hydrogen inlet distribution regulating valve 10, a power unit hydrogen inlet distribution regulating valve 11, a hydrogen-nitrogen gas separator 12, an ammonia-hydrogen internal combustion engine unit 13, a hydrogen fuel cell device 14, a fuel cell output current converter 15, an internal combustion engine output current converter 16, a circuit merging device 17, a battery 18, a battery current converter 19 and heavy-duty equipment 20.

[0035] Among them, the outlet of the ammonia storage tank 1 is connected to the first pipeline 21, and the first pipeline 21 is provided with a pressure reducing valve 2 and an ammonia regulating distribution valve 3. One distribution outlet of the ammonia regulating distribution valve 3 is connected to the multi-stream heat exchanger 4 through a second pipeline 22, and the other distribution outlet of the ammonia regulating distribution valve 3 is connected to the ammonia-hydrogen internal combustion engine unit 13 through a third pipeline 23; the multi-stream heat exchanger 4 is connected to the plate heat exchanger 5 through a fourth pipeline 24, and the plate heat exchanger 5 is connected to the ammonia catalytic cracker 8 through a fifth pipeline 25.

[0036] Multi-stream heat exchanger 4 is connected to air-cooled heat exchanger 6 via sixth and ninth pipelines 26 and 29. Air-cooled heat exchanger 6 is connected to hydrogen fuel cell device 14 via seventh pipeline 27. Hydrogen fuel cell device 14 is connected to multi-stream heat exchanger 4 via eighth pipeline 28. Air-cooled heat exchanger 6 is connected to ammonia-hydrogen internal combustion engine unit 13 via tenth pipeline 30. Ammonia-hydrogen internal combustion engine unit 13 is connected to multi-stream heat exchanger 4 via eleventh pipeline 31. Ammonia-hydrogen internal combustion engine unit 13 is connected to ammonia catalytic cracker 8 via twelfth pipeline 32. Ammonia catalytic cracker 8 is connected to internal combustion engine exhaust treatment device 7 via thirteenth pipeline 33. Ammonia catalytic cracker 8 is connected to plate heat exchanger 5 via fourteenth pipeline 34. Plate heat exchanger 5 is connected to hydrogen-ammonia gas separator 12 via fifteenth pipeline 35.

[0037] One output end of the hydrogen-nitrogen gas separator 12 is connected to a sixteenth pipeline 36, which serves as a nitrogen output pipe. The other output end of the hydrogen-nitrogen gas separator 12 is connected to the ammonia-hydrogen internal combustion engine unit 13 via a seventeenth pipeline 37. The seventeenth pipeline 37 is provided with a burner hydrogen inlet distribution regulating valve 10 and a power unit hydrogen inlet distribution regulating valve 11. The burner hydrogen inlet distribution regulating valve 10 is connected to the hydrogen burner 9 via an eighteenth pipeline 38. The power unit hydrogen inlet distribution regulating valve 11 is connected to the hydrogen fuel cell device 14 via a nineteenth pipeline 39. The hydrogen burner 9 is connected to the ammonia catalytic cracker 8 via a twentieth pipeline 40.

[0038] The ammonia-hydrogen internal combustion engine unit 13 is electrically connected to the internal combustion engine output current converter 16 through a first line 41, the hydrogen fuel cell device 14 is electrically connected to the fuel cell output current converter 15 through a second line 42, the fuel cell output current converter 15 and the internal combustion engine output current converter 16 are electrically connected to the circuit merging device 17, the circuit merging device 17 is electrically connected to the battery current converter 19 and the heavy-load equipment 20 through a third line 43, and the battery current converter 19 is electrically connected to the battery 18 through a fourth line 44.

[0039] Ammonia storage tank 1 stores liquid ammonia and serves as the energy source for the entire system. Multi-stream heat exchanger 4 is used to recycle low-temperature ammonia from the system's internal combustion engine jacket water and fuel cell cooling water to preheat it. Plate heat exchanger 5 is used to preheat the ammonia gas with the hydrogen-ammonia mixture. Air-cooled heat exchanger 6 is used to reduce excess heat from the internal combustion engine jacket water and fuel cell cooling water to a set temperature.

[0040] In this embodiment, after the liquid ammonia and air have completed heat exchange, two pipelines are directly connected to the internal combustion engine and the ammonia catalytic cracker. After catalytic cracking, the produced hydrogen is divided into two pipelines: one to the burner to provide fuel for the burner, and the other to the power unit. The pipeline leading to the power unit is further divided into two, one to the internal combustion engine to provide fuel for the internal combustion engine, and the other to the fuel cell to provide fuel for the fuel cell. The amount of ammonia fed to the internal combustion engine is proportional to the amount of hydrogen fed to the internal combustion engine. The fuel required for burner heat supplementation is input in real time according to system requirements.

[0041] The internal combustion engine exhaust gas treatment device 7 is used to remove nitrogen oxides produced in the internal combustion engine exhaust gas. The catalytic cracker 8 is used to decompose ammonia into hydrogen to provide fuel for the fuel cell, internal combustion engine and burner. It also includes a device for heat exchange with the internal combustion engine exhaust gas to recover part of the heat of the internal combustion engine exhaust gas. The hydrogen burner 9 provides heat to the catalytic device to enable the catalytic process to proceed smoothly. The burner hydrogen inlet regulating distribution valve 10 is used to distribute the hydrogen required for partial combustion to the burner; the power unit hydrogen inlet distribution regulating valve 11 is used to distribute hydrogen to the internal combustion engine and fuel cell. The hydrogen-nitrogen gas separator 12 is used to separate nitrogen and reduce the nitrogen distributed to the combustion device and power unit, thereby reducing the generation of nitrogen oxides and improving the energy conversion efficiency of the system.

[0042] The ammonia-hydrogen internal combustion engine unit 13 and the hydrogen fuel cell device 14 are the main power units of the hybrid system. The current generated passes through the fuel cell output current converter 15 and the internal combustion engine output current converter 16, and is integrated through the circuit merging device 17 to provide power for the heavy-load equipment 20; when the power is insufficient or excessive, it is supplemented or stored by the battery 18.

[0043] like Figure 2 As shown in the figure, simulations of a hybrid power generation system show that when the total amount of hydrogen entering the internal combustion engine and fuel cell is constant, the system's power output has a certain range, and as the power increases, the system's power generation efficiency decreases. The specific value of the system's power output is related to the distribution ratio of hydrogen entering the fuel cell. As the amount of hydrogen entering the fuel cell increases, the overall system output decreases.

[0044] like Figure 3 As shown, through the simulation of the hybrid power generation system, it can be seen that when the total amount of hydrogen input to the internal combustion engine and the fuel cell is a constant value, as the distribution ratio of hydrogen entering the fuel cell increases, the output power of the system decreases, and the distribution ratio of one fuel cell corresponds to one output power of the system.

[0045] like Figure 4As shown, an embodiment of the present invention further provides an efficient control method for ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment, the efficient control method comprising:

[0046] Step S1: Under the load condition that meets the requirements of the entire heavy-duty equipment process, the amount of hydrogen entering the internal combustion engine and the fuel cell is controlled to be constant, and a certain efficiency lower limit is set to ensure that the output efficiency of the system is always in the high-efficiency range during operation, thereby determining the output range;

[0047] Step S2, then adjusting the distribution ratio of hydrogen entering the fuel cell to achieve power output within a certain range of the hydrogen intake;

[0048] Step S3: When the load power is less than the power output range, the system output is at the minimum power output, and the excess power is provided to the battery for storage; when the load power is greater than the power output range, the system output is at the maximum power output, and the insufficient power is provided by the battery.

[0049] In step S1 , when the total amount of hydrogen entering the internal combustion engine and the fuel cell is constant, as the distribution ratio of hydrogen entering the fuel cell increases, the output power of the system decreases, and the distribution ratio of one fuel cell corresponds to one output power of the system.

[0050] Step S3 includes: Step S31, when the load power is less than the power output range, determining the SOC (state of charge) of the battery; if the SOC of the battery does not exceed the upper threshold, the system output is at minimum power output, and the excess power is provided to the battery for storage; if the SOC of the battery exceeds the upper threshold, the system stops working, and the load is fully provided by the battery;

[0051] Step S3 also includes: Step S32, if the SOC of the battery is not lower than the set lower threshold, the system output is based on the maximum power output, and the insufficient power is provided by the battery; if the battery state of charge is lower than the set lower threshold, the lower limit of the power is modified to increase the output power range of the system to supplement part of the battery power.

[0052] In order to solve the problems of long response time and large number of active control valves in the current power following algorithm for hydrogen distribution of power units, this embodiment provides an efficient control method for ammonia hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment, that is, controlling the total amount of hydrogen entering the internal combustion engine and fuel cell to a constant value, and adjusting the hydrogen distribution ratio entering the fuel cell to achieve power output within a certain range of the hydrogen input amount. This method can effectively reduce the number of valves to be regulated. The active control valves of the entire system only have the distribution ratio valves leading to the internal combustion engine and fuel cell, which can quickly respond to the operating conditions of heavy-duty equipment. At the same time, it can also ensure that the SOC of the battery is in a healthy state and improve battery life. Since the efficiency of the fuel cell is higher than that of the internal combustion engine, the proportion allocated to the internal combustion engine can be limited in a lower operating load range, thereby using part of the power in exchange for efficiency improvement. This technical solution can also effectively reduce the final remaining power of the battery and reduce some of the demand for the battery.

[0053] like Figure 5 As shown, based on the above efficient control method, combined with Figure 2 To further clarify, because fuel cells are more efficient than internal combustion engines, they can operate more efficiently within a lower load range. Therefore, under load conditions that meet the requirements for heavy equipment operation, the system's lower efficiency limit can be set at 1. By limiting the upper limit of the hydrogen intake ratio for the internal combustion engine, the system's output power can be shifted from the upper limit to 1, thereby trading some power for increased efficiency. If the load exceeds the output range while the battery's SOC falls below the lower threshold, the lower efficiency limit is shifted from 1 to 1', increasing the system's output power range.

[0054] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention shall be determined by the appended claims and the scope defined therein.

Claims

1. A heavy-duty equipment-based ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system, characterized in that: The invention comprises an ammonia storage tank (1), a pressure reducing valve (2), an ammonia regulating and distributing valve (3), a multi-stream heat exchanger (4), a plate heat exchanger (5), an air-cooled heat exchanger (6), an internal combustion engine tail gas treatment device (7), an ammonia catalytic cracker (8), a hydrogen burner (9), a burner hydrogen inlet distribution regulating valve (10), a power unit hydrogen inlet distribution regulating valve (11), a hydrogen-nitrogen gas separator (12), an ammonia-hydrogen internal combustion engine unit (13), a hydrogen fuel cell device (14), a fuel cell output current converter (15), an internal combustion engine output current converter (16), a circuit merging device (17), a battery (18), a battery current converter (19), and a heavy-duty equipment (20); The output end of the ammonia storage tank (1) is connected to a first pipeline (21), and a pressure reducing valve (2) and an ammonia regulating distribution valve (3) are provided on the first pipeline (21); one distribution outlet of the ammonia regulating distribution valve (3) is connected to a multi-stream heat exchanger (4) through a second pipeline (22), and another distribution outlet of the ammonia regulating distribution valve (3) is connected to an ammonia-hydrogen internal combustion engine unit (13) through a third pipeline (23); the multi-stream heat exchanger (4) is connected to a plate heat exchanger (5) through a fourth pipeline (24), and the plate heat exchanger (5) is connected to an ammonia catalytic cracker (8) through a fifth pipeline (25); The multi-stream heat exchanger (4) is connected to the air-cooled heat exchanger (6) via a sixth pipeline (26) and a ninth pipeline (29); the air-cooled heat exchanger (6) is connected to the hydrogen fuel cell device (14) via a seventh pipeline (27); the hydrogen fuel cell device (14) is connected to the multi-stream heat exchanger (4) via an eighth pipeline (28); the air-cooled heat exchanger (6) is connected to the ammonia-hydrogen internal combustion engine unit (13) via a tenth pipeline (30); the ammonia-hydrogen internal combustion engine unit (13) is connected to the hydrogen fuel cell device (14) via an eighth pipeline (28); The eleventh pipeline (31) is connected to the multi-stream heat exchanger (4); the ammonia-hydrogen internal combustion engine unit (13) is connected to the ammonia catalytic cracker (8) via the twelfth pipeline (32); the ammonia catalytic cracker (8) is connected to the internal combustion engine exhaust gas treatment device (7) via the thirteenth pipeline (33); the ammonia catalytic cracker (8) is connected to the plate heat exchanger (5) via the fourteenth pipeline (34); the plate heat exchanger (5) is connected to the hydrogen-nitrogen gas separator (12) via the fifteenth pipeline (35); One output end of the hydrogen-nitrogen gas separator (12) is connected to a sixteenth pipeline (36), which serves as a nitrogen output pipe; the other output end of the hydrogen-nitrogen gas separator (12) is connected to an ammonia-hydrogen internal combustion engine unit (13) via a seventeenth pipeline (37); a burner hydrogen inlet distribution regulating valve (10) and a power unit hydrogen inlet distribution regulating valve (11) are provided on the seventeenth pipeline (37); the burner hydrogen inlet distribution regulating valve (10) is connected to a hydrogen burner (9) via an eighteenth pipeline (38); the power unit hydrogen inlet distribution regulating valve (11) is connected to a hydrogen fuel cell device (14) via a nineteenth pipeline (39); and the hydrogen burner (9) is connected to an ammonia catalytic cracker (8) via a twentieth pipeline (40); The ammonia hydrogen internal combustion engine unit (13) is electrically connected to the internal combustion engine output current converter (16) via a first circuit (41), the hydrogen fuel cell device (14) is electrically connected to the fuel cell output current converter (15) via a second circuit (42), the fuel cell output current converter (15) and the internal combustion engine output current converter (16) are electrically connected to a circuit merging device (17), the circuit merging device (17) is electrically connected to a battery current converter (19) and a heavy-load equipment (20) via a third circuit (43), and the battery current converter (19) is electrically connected to a battery (18) via a fourth circuit (44).

2. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 1 is characterized in that: The ammonia storage tank (1) is used to store liquid ammonia and is the energy source of the entire system; the multi-stream heat exchanger (4) is a device used to recycle the internal combustion engine cylinder jacket water and fuel cell cooling water in the system to preheat low-temperature ammonia; the plate heat exchanger (5) is a device used to perform secondary preheating of ammonia gas by using the hydrogen-ammonia mixed gas; and the air-cooled heat exchanger (6) is a heat exchange device used to reduce the excess temperature of the internal combustion engine cylinder jacket water and fuel cell cooling water to a set temperature.

3. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 1 is characterized in that: The internal combustion engine exhaust gas treatment device (7) is used to remove nitrogen oxides generated in the internal combustion engine exhaust gas; the catalytic cracker (8) is used to decompose ammonia into hydrogen to provide fuel for the fuel cell, the internal combustion engine and the burner, and also includes a device for exchanging heat with the internal combustion engine exhaust gas to recover part of the heat of the internal combustion engine exhaust gas; the hydrogen burner (9) provides heat for the catalytic device to enable the catalytic process to proceed smoothly; the burner hydrogen inlet regulating distribution valve (10) is used to distribute the hydrogen required for partial combustion to the burner; the power unit hydrogen inlet distribution regulating valve (11) is used to distribute hydrogen to the internal combustion engine and the fuel cell; the hydrogen-nitrogen gas separator (12) is used to separate nitrogen and reduce the nitrogen distributed to the combustion device and the power unit, thereby reducing the generated nitrogen oxides and improving the energy conversion efficiency of the system.

4. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 1 is characterized in that: The ammonia-hydrogen internal combustion engine unit (13) and the hydrogen fuel cell device (14) are the main power units of the system. The current generated passes through the fuel cell output current converter (15) and the internal combustion engine output current converter (16), and is then integrated through the circuit merging device (17) to provide power for the heavy-load equipment (20); and when the power is insufficient or excessive, it is supplemented or stored through the battery (18).

5. An efficient control method for ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to any one of claims 1 to 4, characterized in that: The efficient control method comprises: Step S1: Under the load condition that meets the requirements of the entire heavy-duty equipment process, the amount of hydrogen entering the internal combustion engine and the fuel cell is controlled to be constant, and a certain efficiency lower limit is set to ensure that the output efficiency of the system is always in the high-efficiency range during operation, thereby determining the output range; Step S2, then adjusting the distribution ratio of hydrogen entering the fuel cell to achieve power output within a certain range of the hydrogen intake; Step S3: When the load power is less than the power output range, the system output is at the minimum power output, and the excess power is provided to the battery for storage; when the load power is greater than the power output range, the system output is at the maximum power output, and the insufficient power is provided by the battery.

6. The efficient control method of ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 5 is characterized in that: In step S1 , when the total amount of hydrogen entering the internal combustion engine and the fuel cell is constant, as the distribution ratio of hydrogen entering the fuel cell increases, the output power of the system decreases, and the distribution ratio of one fuel cell corresponds to one output power of the system.

7. The efficient control method of ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 5 is characterized in that: Step S3 includes: Step S31, when the load power is less than the power output range, the SOC of the battery is judged. If the SOC of the battery does not exceed the set upper threshold, the system output is based on the minimum power output, and the excess power is provided to the battery for storage; if the SOC of the battery exceeds the set upper threshold, the system stops working and the load is entirely provided by the battery.

8. The efficient control method of ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 7 is characterized in that: Step S3 also includes: Step S32, if the SOC of the battery is not lower than the set threshold lower limit, the system output is based on the maximum power output, and the insufficient power is provided by the battery; if the SOC of the battery is lower than the set threshold lower limit, the lower limit of the efficiency is modified to increase the output power range of the system to supplement part of the battery power.

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