A hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and its step control method

Abstract

The present invention discloses a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and a step control method thereof. The step hydrogen advancement control method adopts an efficiency-main control mode, that is, when the operating load is lower than the output power corresponding to the highest efficiency of the original large total amount of hydrogen intake, the total amount of hydrogen intake is reduced to achieve the output efficiency in the original total amount of hydrogen intake mode under the condition of low operating load, and to a certain extent, expand the output power range, which can effectively improve the working efficiency of the whole system, and while reducing the demand for ammonia, it can also reduce the working time, peak value and capacity demand of the battery, and reduce the remaining power of the battery after the operation. The step hydrogen advancement control method of the present invention improves the response speed, working efficiency and working life of the battery of the whole system, reduces the working time, storage capacity and charging and discharging peak power of the battery, and reduces the amount of ammonia carried by heavy-duty equipment and the economic cost.

Description

Technical Field

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

[0002] During operation, heavy-load equipment has the characteristics of high load fluctuation frequency and large load fluctuation amplitude. Therefore, it poses certain challenges to the power unit selected during the operation of heavy-load equipment: the power unit of heavy-load equipment is required to have high load output power, a wide range of variable output power, fast load response speed, easy to carry, store and transport fuel, and simple control method.

[0003] As a traditional power plant, the internal combustion engine has a long history of development and is widely used due to its mature technology, rapid energy conversion, low cost, and high output power. As an emerging power plant, the proton exchange membrane fuel cell utilizes a chemical reaction to convert hydrogen into electricity, surpassing the "Carnot efficiency" of traditional thermal power plants, offering high power generation efficiency and zero emissions. Furthermore, both the internal combustion engine and fuel cell 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] The hybrid systems of internal combustion engines and proton exchange membrane fuel cells used in heavy-duty equipment both 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 transportation. 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 for heavy-duty equipment has been developed.

[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 strategy of feedback from the back end of the power unit to the front end of the hydrogen inlet of the hybrid system. A large number of valves need to be controlled, which is prone to control errors and control lags.

[0007] Through front-end control, the hybrid system can be directly regulated, 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, an inappropriate power-following strategy with a constant hydrogen intake can easily lead to a large power surplus and, due to the limited power output range, excessive battery operating time. Further improvements are needed. Summary of the Invention

[0008] The present invention provides a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and a step control method thereof, which can solve the problem that a power following strategy with a constant total amount of hydrogen intake in heavy-duty equipment easily generates a large power surplus, while also easily leading to an excessively long battery operating time due to a limited power output range.

[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 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; 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;

[0012] The internal combustion engine exhaust gas treatment device (7) is used to remove nitrogen oxides generated in the internal combustion engine exhaust gas; the ammonia 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 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 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;

[0013] 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 by 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).

[0014] According to an optional embodiment of the present invention, 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).

[0015] According to an optional embodiment of the present invention, the multi-stream heat exchanger (4) is connected to the air-cooled heat exchanger (6) through a sixth pipeline (26) and a ninth pipeline (29), the air-cooled heat exchanger (6) is connected to the hydrogen fuel cell device (14) through a seventh pipeline (27), and the hydrogen fuel cell device (14) is connected to the multi-stream heat exchanger (4) through an eighth pipeline (28); the air-cooled heat exchanger (6) is connected to the ammonia-hydrogen internal combustion engine unit (13) through a tenth pipeline (30), and the ammonia-hydrogen internal combustion engine unit (13) is connected to the multi-stream heat exchanger (4) through an eleventh pipeline (31); the ammonia-hydrogen internal combustion engine unit (13) is connected to the ammonia catalytic cracker (8) through a twelfth pipeline (32); the ammonia catalytic cracker (8) is connected to the internal combustion engine exhaust gas treatment device (7) through a thirteenth pipeline (33); the ammonia catalytic cracker (8) is connected to the plate heat exchanger (5) through a fourteenth pipeline (34); the plate heat exchanger (5) is connected to the hydrogen-nitrogen gas separator (12) through a fifteenth pipeline (35).

[0016] According to an optional embodiment of the present invention, one output end of the hydrogen-nitrogen gas separator (12) is connected to a sixteenth pipeline (36), and the sixteenth pipeline (36) 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) through 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) through an eighteenth pipeline (38); the power unit hydrogen inlet distribution regulating valve (11) is connected to a hydrogen fuel cell device (14) through a nineteenth pipeline (39); and the hydrogen burner (9) is connected to an ammonia catalytic cracker (8) through a twentieth pipeline (40).

[0017] According to an optional embodiment of the present invention, the ammonia hydrogen internal combustion engine unit (13) is electrically connected to the internal combustion engine output current converter (16) through a first circuit (41), the hydrogen fuel cell device (14) is electrically connected to the fuel cell output current converter (15) through a second circuit (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 circuit (43), and the battery current converter (19) is electrically connected to the battery (18) through a fourth circuit (44).

[0018] An embodiment of the present invention further provides a step control method for a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment. The step control method is implemented using a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment as described in the above embodiment. The step control method includes:

[0019] Step S1, before the heavy-load equipment is operated, the total amount of hydrogen in several steps is set and the corresponding power-efficiency diagram is determined;

[0020] Step S2: Starting from the maximum step hydrogen injection amount, determine the highest efficiency output power, and draw an isoefficiency line to connect to the previous step hydrogen injection amount curve, determine the output power corresponding to the highest efficiency of the previous hydrogen injection amount, and find the output power corresponding to the highest efficiency of the hydrogen injection amount. The two output powers correspond to the lowest output power and the highest output power of the hydrogen injection amount respectively; according to the above operation, the hydrogen injection amount is reduced in sequence to determine the power output range of all hydrogen injection amounts;

[0021] Step S3, setting the hydrogen input amount to a certain value for the internal combustion engine and the fuel cell, and starting operation, by adjusting the hydrogen distribution ratio entering the fuel cell, so as to achieve power output within a certain range of the hydrogen input amount;

[0022] When the load power is less than the power output range, the system will judge whether to reduce the total amount of hydrogen intake in a step-by-step manner: if the total amount of hydrogen intake after reduction is less than the set minimum value, and the battery SOC state of charge does not exceed the set upper threshold, the step will be canceled, the output will be based on the minimum power output, and the excess power will be provided to the battery for storage; if the battery SOC state of charge exceeds the set upper threshold, the minimum setting value will be lowered, and the total amount of hydrogen intake will be reduced in a step-by-step manner; if it is not less than the minimum setting value, the total amount of hydrogen intake will be reduced in a step-by-step manner;

[0023] When the load power is greater than the power output range, the system judges whether to increase the total amount of hydrogen intake in a step-by-step manner: if the total amount of hydrogen intake after the increase is greater than the set maximum value, and the battery SOC state of charge is not lower than the set threshold lower limit, the step is canceled, the output is based on the maximum power output, and the insufficient power is output by the battery; if the battery SOC state of charge is lower than the set threshold lower limit, the maximum set value is increased, and the total amount of hydrogen intake is increased in a step-by-step manner; if it is not greater than the maximum set value, the total amount of hydrogen intake is increased in a step-by-step manner.

[0024] According to an optional embodiment of the present invention, when the battery is working in step S3, the SOC state of charge of the battery is judged: when the SOC state of charge of the battery does not exceed the threshold value, the working state of the battery is maintained; when the SOC of the battery exceeds the upper threshold value, the minimum set value is lowered and the total amount of hydrogen intake is reduced in a stepwise manner, and the process of judging the total amount of hydrogen intake in step S3 is returned; when the SOC state of charge of the battery is lower than the lower threshold value, the maximum set value is increased and the total amount of hydrogen intake is increased in a stepwise manner, and the process of judging the total amount of hydrogen intake in step S3 is returned.

[0025] According to an optional embodiment of the present invention, the step control method further includes: step 4, changing the total amount of hydrogen intake of the internal combustion engine and the fuel cell in a stepwise and discontinuous manner within a specific load range.

[0026] Compared with the prior art, the embodiments of the present invention provide a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and a step control method thereof, which has the following beneficial effects:

[0027] (1) To address the long response time and large number of active control valves in the current power-following algorithm for hydrogen intake distribution, the present invention proposes a constant hydrogen intake control strategy: that is, the total amount of hydrogen entering the internal combustion engine and fuel cell is controlled to a constant value, and the hydrogen distribution ratio entering the fuel cell is controlled to achieve power output within a certain range of the hydrogen intake amount. This strategy can effectively reduce the number of valves to be regulated. The active control valves in the entire system are only 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.

[0028] (2) The constant hydrogen injection control strategy has a limited power coverage range, and at the same output power, the greater the constant hydrogen injection rate, the higher the efficiency. Therefore, to address the shortcomings of the constant hydrogen injection control strategy, the present invention proposes two step-type control strategies that complement different hydrogen injection characteristics and effectively improve the system's operating performance.

[0029] (3) In order to improve the output coverage of the hybrid power generation system, the step hydrogenation control method of the present invention can adopt a power-main control method, that is, when the operating load is lower than the minimum output power of the original larger total amount of hydrogen intake, the lower load following is achieved by reducing the total amount of hydrogen intake, which can effectively reduce the working time and working peak of the battery, as well as reduce the system's demand for battery capacity and reduce the remaining power of the battery after the operation is completed, effectively improving the performance requirements of the battery and maintaining the health of the battery.

[0030] (4) To effectively improve the output efficiency of the hybrid system, the step-by-step hydrogen injection control method of the present invention can adopt an efficiency-based control method. That is, when the operating load is lower than the output power corresponding to the highest efficiency of the original large total hydrogen injection, the total hydrogen injection amount is reduced to achieve the output efficiency under the original total hydrogen injection mode under the low operating load, and to a certain extent, expand the output power range. This can effectively improve the operating efficiency of the entire system, reduce the demand for ammonia, and also reduce the operating time, peak and capacity requirements of the battery, while also reducing the remaining battery power after the operation ends.

[0031] (5) Compared with the current power following algorithm to realize the power following strategy of heavy-load equipment, the technical solution mentioned in the present invention can effectively improve the response speed of the hybrid power generation system, reduce the number of active control valves, meet the operation requirements of heavy-load equipment, and effectively reduce the required capacity, operating time and charging and discharging peak of the battery, reduce the weight of ammonia carried by heavy-load 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

[0032] 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.

[0033] Figure 1 A schematic diagram of the functional module connections of a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application.

[0034] Figure 2 A schematic diagram of the main power control of a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment is provided in an embodiment of the present application.

[0035] Figure 3 A schematic diagram of the main efficiency control of a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment is provided in an embodiment of the present application.

[0036] Figure 4 A power-efficiency relationship diagram for different total hydrogen intake amounts of a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application.

[0037] Figure 5 A power-efficiency diagram of a power-main control system for a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application.

[0038] Figure 6 A power-efficiency diagram of another efficiency-mainly controlled system for hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] 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.

[0040] The present invention provides a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment and a step control method thereof, which relates to the field of hydrogen energy development and utilization and energy management of complex systems. It adopts a step-by-step hydrogen control strategy and takes into account the SOC health of the battery according to the control strategy, thereby improving the response speed and working efficiency of the overall system and the working life of the battery, reducing the battery's working time, storage capacity and charging and discharging peak power, and reducing the amount of ammonia carried by heavy-duty equipment and the economic cost.

[0041] like Figure 1 As shown, an embodiment of the present invention provides an ammonia hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment, including 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.

[0042] Ammonia storage tank 1 is used to store liquid ammonia and is the energy source of the entire system; 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; plate heat exchanger 5 is a device used to perform secondary preheating of ammonia gas with hydrogen-ammonia mixed gas; air-cooled heat exchanger 6 is a heat exchange device used to reduce excess temperature of the internal combustion engine cylinder jacket water and fuel cell cooling water to a set temperature.

[0043] 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.

[0044] The internal combustion engine exhaust gas treatment device 7 is used to remove nitrogen oxides generated in the internal combustion engine exhaust gas; the ammonia catalytic cracker 8 is used to decompose ammonia into hydrogen to provide fuel for the fuel cell, internal combustion engine and burner, and 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.

[0045] 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 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 through the battery 18.

[0046] The specific connection relationship of the functional modules of a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment is as follows:

[0047] The output end of the ammonia storage tank 1 is connected to a first pipeline 21, on which a pressure reducing valve 2 and an ammonia regulating distribution valve 3 are provided. 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.

[0048] 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 multi-stream heat exchanger 4 via an eleventh pipeline 31. The ammonia-hydrogen internal combustion engine unit 13 is connected to the ammonia catalytic cracker 8 via a twelfth pipeline 32. The ammonia catalytic cracker 8 is connected to the internal combustion engine exhaust treatment device 7 via a thirteenth pipeline 33. The ammonia catalytic cracker 8 is connected to the plate heat exchanger 5 via a fourteenth pipeline 34. The plate heat exchanger 5 is connected to the hydrogen-nitrogen gas separator 12 via a fifteenth pipeline 35.

[0049] 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.

[0050] 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.

[0051] like Figure 2 As shown in the figure: After testing, it was found that the power range and efficiency corresponding to different total hydrogen intake amounts are different. When the total hydrogen intake amount is small, the system's power generation range is small, but the system's power generation lower limit is widened and power generation efficiency is improved. When the total hydrogen intake amount is large, the system's power generation range is widened, with a higher lower limit but also a higher upper limit, and corresponding to the same output power, the efficiency is also higher.

[0052] like Figure 3 As shown, after testing, it was found that under the same total amount of hydrogen input, as the hydrogen input distribution ratio of the fuel cell increases, the output power of the system decreases, and one hydrogen input distribution ratio corresponds to one system output power.

[0053] like Figure 4 As shown, an embodiment of the present invention further provides a step control method for a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment. The step control method is implemented using a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment in the above embodiment, wherein the step control method includes:

[0054] Step S1, before the heavy-load equipment is operated, the total amount of hydrogen in several steps is set and the corresponding power-efficiency diagram is determined;

[0055] Step S2: Starting from the maximum step hydrogen injection amount, determine the highest efficiency output power, and draw an isoefficiency line to connect to the previous step hydrogen injection amount curve, determine the output power corresponding to the highest efficiency of the previous hydrogen injection amount, and find the output power corresponding to the highest efficiency of the hydrogen injection amount. The two output powers correspond to the lowest output power and the highest output power of the hydrogen injection amount respectively; according to the above operation, the hydrogen injection amount is reduced in sequence to determine the power output range of all hydrogen injection amounts;

[0056] Step S3, setting the hydrogen input amount to a certain value for the internal combustion engine and the fuel cell, and starting operation, by adjusting the hydrogen distribution ratio entering the fuel cell, so as to achieve power output within a certain range of the hydrogen input amount;

[0057] When the load power is less than the power output range, the system will judge whether to reduce the total amount of hydrogen intake in a step-by-step manner: if the total amount of hydrogen intake after reduction is less than the set minimum value, and the battery SOC state of charge does not exceed the set upper threshold, the step will be canceled, the output will be based on the minimum power output, and the excess power will be provided to the battery for storage; if the battery SOC state of charge exceeds the set upper threshold, the minimum setting value will be lowered, and the total amount of hydrogen intake will be reduced in a step-by-step manner; if it is not less than the minimum setting value, the total amount of hydrogen intake will be reduced in a step-by-step manner;

[0058] When the load power is greater than the power output range, the system judges whether to increase the total amount of hydrogen intake in a step-by-step manner: if the total amount of hydrogen intake after the increase is greater than the set maximum value, and the battery SOC state of charge is not lower than the set threshold lower limit, the step is canceled, the output is based on the maximum power output, and the insufficient power is output by the battery; if the battery SOC state of charge is lower than the set threshold lower limit, the maximum set value is increased, and the total amount of hydrogen intake is increased in a step-by-step manner; if it is not greater than the maximum set value, the total amount of hydrogen intake is increased in a step-by-step manner.

[0059] Preferably, when the battery is working in step S3, the SOC state of charge of the battery is judged: when the SOC state of charge of the battery does not exceed the threshold value, the working state of the battery is maintained; when the SOC state of charge of the battery exceeds the upper limit of the threshold value, the minimum setting value is lowered and the total amount of hydrogen intake is reduced in a stepwise manner, and the process of judging the total amount of hydrogen intake in step S3 is returned; when the SOC state of charge of the battery is lower than the lower limit of the threshold value, the maximum setting value is increased and the total amount of hydrogen intake is increased in a stepwise manner, and the process of judging the total amount of hydrogen intake in step S3 is returned.

[0060] Preferably, the step control method further includes: step 4, changing the total amount of hydrogen intake of the internal combustion engine and the fuel cell in a stepwise and discontinuous manner within a specific load range.

[0061] The present invention provides a step control method for a hydrogen production, internal combustion engine and fuel cell hybrid system based on heavy-load equipment, which can effectively reduce the number of valve controls. The active control valves of the entire system only have the distribution proportional valves leading to the internal combustion engine and the fuel cell, which can quickly respond to the operating conditions of the heavy-load equipment, while improving the SOC state of charge health of the battery. It can also effectively improve the output efficiency of the hybrid system on the basis of power main control and reduce the amount of ammonia carried by the heavy-load equipment.

[0062] like Figure 5 As shown, in order to understand the working principle of the power main control, combined with Figure 1 Explanation: When the load power is less than 1, the total amount of hydrogen intake by the internal combustion engine and fuel cell is maintained at a low level. When the load power is between 1 and 2, the total amount of hydrogen intake by the internal combustion engine and fuel cell is increased in steps to maintain the total amount of hydrogen intake at a normal level. When the load power is greater than 3, the total amount of hydrogen intake by the internal combustion engine and fuel cell is increased in steps to maintain the total amount of hydrogen intake at a higher level. By reducing the total amount of hydrogen intake to achieve lower load tracking, the battery's operating time and peak operating time can be effectively reduced, as well as the system's demand on battery capacity. This reduces the battery's remaining charge after operation, effectively improving performance requirements and maintaining battery health.

[0063] like Figure 6 As shown, in order to understand the working principle of efficiency main control, combined with Figure 1Expanded explanation: When the load power is less than 1, the total amount of hydrogen fed to the internal combustion engine and fuel cell remains low. When the load power is between 1 and 1', the total amount of hydrogen fed remains unchanged, and the system output is maintained at 1'. When the load power is between 1' and 2, the total amount of hydrogen fed to the internal combustion engine and fuel cell is increased in steps to maintain the total amount of hydrogen fed. When the load power is between 2 and 2', the total amount of hydrogen fed remains unchanged, and the system output is maintained at 2'. When the load power is greater than 3, the total amount of hydrogen fed to the internal combustion engine and fuel cell is increased in steps to maintain the total amount of hydrogen fed. By reducing the total amount of hydrogen fed, the output efficiency of the original total amount of hydrogen fed mode is improved at low operating loads, and the output power range is expanded to a certain extent. This effectively improves the operating efficiency of the entire system, reduces the demand for ammonia, and also reduces the operating time and peak value of the battery, increases the system's demand for battery capacity, and reduces the remaining battery charge at the end of operation.

[0064] 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 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; 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; The internal combustion engine exhaust gas treatment device (7) is used to remove nitrogen oxides generated in the internal combustion engine exhaust gas; the ammonia 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 to the catalytic device to enable the catalytic process to proceed smoothly; the burner hydrogen inlet distribution regulating 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; 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 by 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).

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 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).

3. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 2 is characterized in that: 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); and the plate heat exchanger (5) is connected to the hydrogen-nitrogen gas separator (12) via the fifteenth pipeline (35).

4. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 3 is characterized in that: 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).

5. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 4 is characterized in that: The ammonia hydrogen internal combustion engine unit (13) is electrically connected to the internal combustion engine output current converter (16) through a first circuit (41), the hydrogen fuel cell device (14) is electrically connected to the fuel cell output current converter (15) through a second circuit (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 circuit (43), and the battery current converter (19) is electrically connected to the battery (18) through a fourth circuit (44).

6. A step control method for a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment, wherein the step control method is implemented using a hydrogen production, internal combustion engine, and fuel cell hybrid system based on heavy-duty equipment as described in any one of claims 1 to 5, characterized in that: The step control method comprises: Step S1, before the heavy-load equipment is operated, the total amount of hydrogen in several steps is set and the corresponding power-efficiency diagram is determined; Step S2: Starting from the maximum step hydrogen injection amount, determine the highest efficiency output power, and draw an isoefficiency line to connect to the previous step hydrogen injection amount curve, determine the output power corresponding to the highest efficiency of the previous hydrogen injection amount, and find the output power corresponding to the highest efficiency of the hydrogen injection amount. The two output powers correspond to the lowest output power and the highest output power of the hydrogen injection amount respectively; according to the above operation, the hydrogen injection amount is reduced in sequence to determine the power output range of all hydrogen injection amounts; Step S3, setting the hydrogen input amount to a certain value for the internal combustion engine and the fuel cell, and starting operation, by adjusting the hydrogen distribution ratio entering the fuel cell, so as to achieve power output within a certain range of the hydrogen input amount; When the load power is less than the power output range, the system will judge whether to reduce the total amount of hydrogen intake in a step-by-step manner: if the total amount of hydrogen intake after reduction is less than the set minimum value and the battery SOC does not exceed the set upper threshold, the step will be canceled and the output will be at the minimum power output, and the excess power will be provided to the battery for storage; if the battery SOC exceeds the set upper threshold, the minimum setting value will be lowered and the total amount of hydrogen intake will be reduced in a step-by-step manner; if it is not less than the minimum setting value, the total amount of hydrogen intake will be reduced in a step-by-step manner; When the load power is greater than the power output range, the system judges whether to increase the total amount of hydrogen intake in a step-by-step manner: if the total amount of hydrogen intake after the increase is greater than the set maximum value and the battery SOC is not lower than the set threshold lower limit, the step is canceled, the output is based on the maximum power output, and the insufficient power is output by the battery; if the battery SOC is lower than the set threshold lower limit, the maximum set value is increased, and the total amount of hydrogen intake is increased in a step-by-step manner; if it is not greater than the maximum set value, the total amount of hydrogen intake is increased in a step-by-step manner.

7. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 6 is characterized in that: When the battery is working in step S3, the SOC of the battery is judged: when the SOC of the battery does not exceed the threshold, the working state of the battery is maintained; when the SOC of the battery exceeds the upper threshold, the minimum setting value is lowered and the total amount of hydrogen intake is reduced in a stepwise manner, and the process of judging the total amount of hydrogen intake in step S3 is returned; when the SOC of the battery is lower than the lower threshold, the maximum setting value is increased and the total amount of hydrogen intake is increased in a stepwise manner, and the process of judging the total amount of hydrogen intake in step S3 is returned.

8. The ammonia-to-hydrogen, internal combustion engine and fuel cell hybrid system based on heavy-duty equipment according to claim 6 is characterized in that: The step control method further includes: step 4, changing the total amount of hydrogen intake of the internal combustion engine and the fuel cell in a stepwise and discontinuous manner within a specific load range.

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