Vehicle-mounted ammonia cracking hydrogen generation system of an ammonia engine and associated thermal management process

Abstract

The present invention relates to a vehicle-mounted ammonia cracking hydrogen generation system for an ammonia engine and a thermal management method therefor. The system comprises a liquid ammonia storage tank, a liquid ammonia gasification preheating tank, a hydrogen generation line, a cracking gas storage line, an ammonia hydrogen inlet channel premixing pipe, an ammonia oxidation plant heat generation line, an air supply line, and an end gas supply line.The heat from the ammonia oxidation plant heat generation line not only provides heat for cracking ammonia, but also preheats the ammonia required for cracking; the ammonia required by the ammonia oxidation plant heat generation line is preheated, and the heat, along with the exhaust gas heat from an engine, is supplied to an aftertreatment system; the molar ratio of the supplied ammonia to that of the air is adjusted according to the engine's operating conditions to modify the heat release from the ammonia oxidation plant heat generation line, and the reaction is carried out according to the most suitable reaction equation, thus avoiding the generation of exhaust gas pollutants; furthermore, the heat is distributed and managed with the ammonia oxidation plant heat generation line as its core.

Description

A vehicle-mounted ammonia cracking hydrogen production system for an ammonia engine and a thermal management method thereof Technical Field

[0001] The present application relates to the field of energy-saving and new energy vehicle technology, and in particular to an on-board ammonia cracking hydrogen production system for an ammonia engine and a thermal management method thereof. Background Art

[0002] The fuel system of an ammonia fuel compression ignition internal combustion engine is divided into:

[0003] a) Mode: Ammonia + diesel mixed combustion, no hydrogen required.

[0004] b) Mode: Ammonia + hydrogen mixed combustion, the ammonia source is the on-board liquid ammonia storage tank; the hydrogen source is the on-board hydrogen storage tank and the on-board ammonia cracking hydrogen production system.

[0005] As the reverse reaction to ammonia synthesis, ammonia thermal cracking is an endothermic reaction, and under certain conditions, the ammonia conversion rate is subject to thermodynamic limitations. At 450°C, the thermodynamic equilibrium conversion rate of ammonia cracking is above 99%. However, due to the kinetic limitations of the reaction under practical conditions, achieving 99% conversion in on-board cracking, when equipped with a catalyst, requires increasing the reaction temperature to 600°C. Furthermore, considering heat losses during the heat exchange process, the hot flue gas temperature, which serves as the heat source for the ammonia cracking reaction, must be above 650°C.

[0006] In the prior art, hot flue gas comes from:

[0007] 1) The exhaust gas from the exhaust pipe is hot. Its disadvantage is that the exhaust gas temperature from the exhaust pipe is relatively low. Under most working conditions, the exhaust gas temperature cannot reach 650°C.

[0008] 2) Electric heating: The advantage is simple control, but its disadvantages are low heating power density and high cost;

[0009] 3) The ammonia oxidation reactor produces heat. The advantage is that the thermal power density is high, but the disadvantage is that the heat output is difficult to control. The reaction produces NOx and N2O, which worsens the exhaust emissions of the entire vehicle.

[0010] Therefore, in view of the above shortcomings of hot flue gas sources, a thermal management method for an ammonia internal combustion engine ammonia cracking hydrogen production system is proposed, which can solve the thermal management problem centered on the ammonia oxidation reactor.

[0011] Summary of the Invention

[0012] The embodiments of the present application provide an on-board ammonia cracking hydrogen production system for an ammonia engine and a thermal management method thereof to address the problem in the related art that the heat generation of an ammonia oxidation reactor is difficult to control, and the reaction produces NOx and N2O, which worsens the exhaust emissions of the entire vehicle.

[0013] In a first aspect, a vehicle-mounted ammonia cracking hydrogen production system for an ammonia engine is provided, comprising:

[0014] A liquid ammonia storage tank and a liquid ammonia gasification preheating tank are connected in sequence; the gas outlet of the liquid ammonia gasification preheating tank is connected to a first ammonia delivery pipe, a second ammonia delivery pipe, a third ammonia delivery pipe and a fourth ammonia delivery pipe;

[0015] A hydrogen generation pipeline, the gas inlet of which is connected to the first ammonia delivery pipeline, and the gas outlet of which is connected to the ammonia-hydrogen gas premixing pipe through the cracked gas storage pipeline; the ammonia-hydrogen gas premixing pipe is also connected to the second ammonia delivery pipeline;

[0016] an ammonia oxidizer heat generating pipeline connected to the third ammonia delivery pipeline and used to supply heat to the hydrogen generation pipeline; the ammonia oxidizer heat generating pipeline is connected to a first hydrogen oxidizing hot gas pipeline and a second hydrogen oxidizing hot gas pipeline; the first hydrogen oxidizing hot gas pipeline is used to preheat the ammonia in the first ammonia delivery pipeline;

[0017] An air delivery pipeline, which is used to supply oxygen to the ammonia-hydrogen gas premixing pipe and the ammonia oxidizer heat generation pipeline, and control the oxygen delivery amount;

[0018] The tail gas delivery pipeline includes a first tail gas branch and a second tail gas branch; the second tail gas branch is used to preheat the ammonia of the third ammonia delivery pipeline; the first tail gas branch is used to be connected to the air inlet of the tail gas after-treatment system, and the second hydrogen oxidizing hot gas pipeline and the fourth ammonia delivery pipeline are also used to be connected to the air inlet of the tail gas after-treatment system.

[0019] In some embodiments, the liquid ammonia vaporization preheating tank includes a primary preheating chamber and a secondary preheating chamber that are connected to each other;

[0020] The first-level preheating chamber is in communication with the second tail gas branch, and is connected to the third ammonia delivery pipe and the second ammonia delivery pipe;

[0021] The secondary preheating chamber is connected to the first ammonia delivery pipe and the fourth ammonia delivery pipe, and the first hydrogen oxidation hot gas pipeline is communicated with the secondary preheating chamber.

[0022] In some embodiments, the hydrogen generation pipeline includes a first stop valve, an ammonia cracker, a cracked gas collection pipe, and a second stop valve connected in sequence;

[0023] The heat-generating pipeline of the ammonia oxidizer includes a third stop valve, an ammonia oxidizer and an air outlet pipe which are connected in sequence; heat is exchanged between the ammonia oxidizer and the ammonia cracker via a heat exchanger.

[0024] In some embodiments, the cracked gas storage pipeline includes a mixed gas buffer tank, a hydrogen flow meter, and a sixth shut-off valve connected in sequence.

[0025] In some embodiments, the air delivery pipeline includes a first air branch and a second air branch; the first air branch is connected to the ammonia-hydrogen gas premixing pipe, and the second air branch is connected to the third ammonia delivery pipe through an air compression pump.

[0026] In some embodiments, the exhaust gas delivery pipeline further includes a third exhaust gas branch, and the third exhaust gas branch is connected to the first air branch through a seventh shut-off valve.

[0027] In a second aspect, a thermal management method for an on-board ammonia cracking hydrogen production system of an ammonia engine is provided, comprising the following steps:

[0028] Obtain the heating demand type of the on-board ammonia cracking hydrogen production system to derive the corresponding control strategy;

[0029] In response to the control strategy, the ammonia and oxygen supply amounts are controlled.

[0030] In some embodiments, when the heat supply demand is for an engine cold start condition, the control strategy is:

[0031] Controlling the supply rate of the third ammonia delivery pipeline and the oxygen supply rate of the air delivery pipeline according to gas distribution strategy 1, so that the heat generated by the heat generation pipeline of the ammonia oxidizer meets the heat required for ammonia cracking in the hydrogen generation pipeline, the heat required for the SCR catalyst to be ignited during cold start of the engine, and the heat required for preheating the ammonia in the first ammonia delivery pipeline;

[0032] The hydrogen generated by the hydrogen generation pipeline is transported to the ammonia-hydrogen premixing pipe through the cracked gas storage pipeline to ignite the ammonia transported by the second ammonia pipeline to complete the engine ignition; at the same time, the exhaust heat of the second exhaust branch preheats the ammonia in the third ammonia pipeline.

[0033] In some embodiments, when the heat demand is a steady-state engine operating condition, the control strategy is:

[0034] According to the second gas distribution strategy, the supply amount of the third ammonia pipeline and the oxygen supply amount of the air delivery pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline and the exhaust heat of the first exhaust branch jointly provide heat to the exhaust gas after-treatment system; at the same time, the exhaust heat of the second exhaust branch preheats the ammonia in the third ammonia pipeline.

[0035] In some embodiments, when the heat demand is at a high engine load condition, the control strategy is:

[0036] Controlling the supply rate of the third ammonia delivery pipeline and the oxygen supply rate of the air delivery pipeline according to gas distribution strategy three so that the heat generated by the ammonia oxidizer heat generation pipeline meets the heat required for ammonia cracking in the hydrogen generation pipeline, the heat required for preheating the ammonia in the first ammonia delivery pipeline, and the heat required by the second hydrogen oxidation hot gas pipeline;

[0037] The hydrogen generated by the hydrogen generation pipeline is transported to the ammonia-hydrogen premixing pipe through the cracked gas storage pipeline to ignite the ammonia transported by the second ammonia pipeline; at the same time, the exhaust heat of the second exhaust gas branch preheats the ammonia of the third ammonia pipeline; the exhaust heat of the first exhaust gas branch and the heat of the second hydrogen oxidation hot gas pipeline jointly provide heat for the exhaust gas after-treatment system.

[0038] The beneficial effects of the technical solution provided by this application include:

[0039] The embodiment of the present application provides an on-vehicle ammonia cracking hydrogen production system for an ammonia engine and a thermal management method thereof, wherein the outlet end of the ammonia gasification preheating tank is connected to the first ammonia delivery pipe, the second ammonia delivery pipe, the third ammonia delivery pipe and the fourth ammonia delivery pipe; the air inlet end of the hydrogen generation pipeline is connected to the first ammonia delivery pipe, and the air outlet end is connected to the ammonia-hydrogen gas channel premixing pipe through the cracked gas storage pipeline; the ammonia-hydrogen gas channel premixing pipe is also connected to the second ammonia delivery pipe; the ammonia oxidizer heat generation pipeline is connected to the third ammonia delivery pipe and is used to supply heat to the hydrogen generation pipeline; the ammonia oxidizer heat generation pipeline is connected to the first hydrogen oxidizer heat generation pipeline. The first hydrogen oxidizing hot gas pipeline is used to preheat the ammonia in the first ammonia pipeline; the air delivery pipeline is used to provide oxygen to the ammonia-hydrogen gas premixing pipe and the ammonia oxidizer heat production pipeline, and control the oxygen delivery amount; the exhaust gas delivery pipeline has a first exhaust gas branch and a second exhaust gas branch; the second exhaust gas branch is used to preheat the ammonia in the third ammonia pipeline; the first exhaust gas branch is connected to the air inlet of the exhaust gas after-treatment system, and the air inlet of the exhaust gas after-treatment system is also connected to the second hydrogen oxidizing hot gas pipeline and the fourth ammonia pipeline.

[0040] Through the above pipeline design, the heat of the ammonia oxidizer heat-generating pipeline not only provides heat for ammonia cracking, but also preheats the ammonia required for ammonia cracking and the ammonia required for the ammonia oxidizer, and cooperates with the heat of the engine exhaust gas to jointly provide heat for the after-treatment system. The above heat management method is selected and operated according to different engine operating conditions. At the same time, during operation, the molar ratio of the ammonia and air supply is adjusted according to different engine operating conditions through the third ammonia pipeline and the air delivery pipeline to determine the heat release, and the reaction is carried out with the most appropriate reaction formula to avoid the formation of exhaust pollutants N2O. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] FIG1 is a schematic diagram of an on-board ammonia cracking hydrogen production system for an ammonia engine provided in an embodiment of the present application.

[0043] In the figure: 1. Liquid ammonia storage tank; 2. Liquid ammonia vaporization preheating tank; 3. First ammonia pipeline; 4. Cracking gas storage pipeline; 5. Second ammonia pipeline; 6. Third ammonia pipeline; 7. Fourth ammonia pipeline; 8. Hydrogen generation pipeline; 9. Ammonia oxidizer heat generation pipeline; 10. First hydrogenation hot gas pipeline; 11. Second hydrogenation hot gas pipeline; 12. Ammonia-hydrogen gas premixing pipe; 13. First tail gas branch; 14. Second tail gas branch; 15. First air branch; 16. Second air branch; 17. First stop valve; 18. Second stop valve; 19. Third stop valve; 20. Sixth stop valve; 21. Seventh stop valve; 22. Fourth stop valve; 23. Ammonia cracker; 24. Ammonia oxidizer; 25. Fifth stop valve. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] The embodiments of the present application provide an on-board ammonia cracking hydrogen production system for an ammonia engine and a thermal management method thereof to address the problem in the related art that the heat generation of the ammonia oxidation reactor is difficult to control, and the reaction produces NOx and N2O, which worsens the exhaust emissions of the entire vehicle.

[0046] Please refer to Figure 1, which shows an on-vehicle ammonia cracking hydrogen production system for an ammonia engine, including a liquid ammonia storage tank 1, a liquid ammonia vaporization preheating tank 2, a hydrogen generation pipeline 8, a cracked gas storage pipeline 4, an ammonia-hydrogen gas premixing pipe 12, an ammonia oxidizer heat generation pipeline 9, an air delivery pipeline, and an exhaust gas delivery pipeline.

[0047] Among them, the gas outlet end of the liquid ammonia gasification preheating tank 2 is connected to the first ammonia delivery pipe 3, the second ammonia delivery pipe 5, the third ammonia delivery pipe 6 and the fourth ammonia delivery pipe 7.

[0048] The air inlet end of the hydrogen generation pipeline 8 is connected to the first ammonia pipeline 3, and the air outlet end is connected to the ammonia-hydrogen gas premixing pipe 12 through the cracked gas storage pipeline 4; the ammonia-hydrogen gas premixing pipe 12 is also connected to the second ammonia pipeline 5; the second ammonia pipeline 5 is connected to the ammonia-hydrogen gas premixing pipe 12 through an ammonia flow sensor and an eighth shut-off valve; the ammonia-hydrogen gas premixing pipe 12 is connected to the intake manifold of the engine.

[0049] The air inlet end of the ammonia oxidizer heat generating pipeline 9 is connected to the third ammonia delivery pipeline 6 and is used to supply heat to the hydrogen generation pipeline 8; the air outlet end of the ammonia oxidizer heat generating pipeline 9 is connected to the first hydrogen oxidation hot gas pipeline 10 and the second hydrogen oxidation hot gas pipeline 11; the first hydrogen oxidation hot gas pipeline 10 is used to preheat the ammonia in the first ammonia delivery pipeline 3;

[0050] An air delivery pipeline is used to supply oxygen to the air inlet of the ammonia-hydrogen gas premixing pipe 12 and the ammonia oxidizer heat generating pipeline 9, and to control the oxygen delivery amount;

[0051] The exhaust gas pipeline is the engine's exhaust system and includes a first exhaust gas branch 13 and a second exhaust gas branch 14. The second exhaust gas branch 14 is used to preheat ammonia from the third ammonia pipeline 6 to 550°C for cracking in the hydrogen generation pipeline 8. The first exhaust gas branch 13 is connected to the exhaust gas after-treatment system's air inlet, while the second hydrogen oxidizing gas pipeline 11 and the fourth ammonia pipeline 7 are also connected to the exhaust gas after-treatment system's air inlet. The ammonia reducing agent for the exhaust gas after-treatment system is provided by the vaporized liquid ammonia output from the fourth ammonia pipeline 7, replacing the urea system in the original after-treatment system.

[0052] Through the arrangement of the above pipelines, the heat of the ammonia oxidizer heat-generating pipeline 9 not only provides heat for ammonia cracking, but also preheats the ammonia required for ammonia cracking to quickly react; preheating the ammonia required for the ammonia oxidizer heat-generating pipeline 9 and co-heating the after-treatment system with the exhaust heat of the engine can replace the DOC unit function of the original after-treatment system; the above heat management method is selected for operation according to different engine operating conditions; at the same time, during operation, the molar ratio of the ammonia amount and the air amount supplied is adjusted according to different engine operating conditions through the third ammonia pipe 6 and the air delivery pipeline to determine the heat release of the ammonia oxidizer heat-generating pipeline 9, and the reaction is carried out with the most appropriate reaction formula to avoid the formation of exhaust pollutants N2O.

[0053] It should be understood that the above adjustment of the molar ratio of ammonia and oxygen air supply to change the chemical reaction formula of the operating reaction to avoid the formation of exhaust pollutants N2O; the reaction formula is as follows:

[0054] Reaction formula 1: (1) NH3 + 0.75O2 → 0.5N2 + 1.5H2O; ΔH = -2.26 × 10 5 j / moleNH3

[0055] Reaction formula 2: (2) NH3 + O2 → 0.5N2O + 1.5H2O; ΔH = -2.76 × 10 5 j / moleNH3

[0056] Reaction equation 3: (3) NH3 + 1.25O2 → NO + 1.5H2O; ΔH = -3.17 × 105 j / moleNH3

[0057] Reaction formula 4: (4) NH3 + 1.75O2 → NO2 + 1.5H2O; ΔH = -2.83 × 10 5 j / moleNH3

[0058] That is, by controlling the molar amounts of ammonia and oxygen air supplied, the ammonia reaction equation in the ammonia oxidizer heat generating pipeline 9 is prevented from operating in reaction equation 2, thereby preventing the generation of tail gas pollutants N2O.

[0059] In some preferred embodiments, the structure of the liquid ammonia gasification preheating tank 2 is configured as follows:

[0060] The liquid ammonia gasification preheating tank 2 includes a first-level preheating chamber and a second-level preheating chamber that are connected to each other; the first-level preheating chamber is connected to the second tail gas branch 14, and is connected to the third ammonia pipe 6 and the second ammonia pipe 5 to perform a first-level preheating of the ammonia therein to reach the ammonia oxidation ignition temperature point of 150°C for use in the ammonia oxidizer heat production pipeline 9; the second-level preheating chamber is connected to the first ammonia pipe 3 and the fourth ammonia pipe 7, and the first hydrogen oxidation hot gas pipeline 10 is connected to the second-level preheating chamber, which is used to preheat the ammonia in the third ammonia pipe 6 to reach 550°C.

[0061] In some preferred embodiments, the structures of the hydrogen generation pipeline 8 and the ammonia oxidizer heat generation pipeline 9 are described in detail:

[0062] The hydrogen generation pipeline 8 includes a first stop valve 17, an ammonia cracker 23, a cracked gas collection pipe and a second stop valve 18 connected in sequence;

[0063] The ammonia oxidizer heat generating pipeline 9 includes a third stop valve 19, an ammonia oxidizer 24 and an outlet pipe connected in sequence; heat is exchanged between the ammonia oxidizer 24 and the ammonia cracker 23 through a heat exchanger;

[0064] The efficiency of heat exchange between the ammonia in the inner flow channel of the ammonia cracker 23 and the hot flue gas from the ammonia oxidation in the outer flow channel of the ammonia oxidizer 24 is calibrated. The ammonia supply rate of the ammonia cracker 23 is matched with the cracking hydrogen production. That is, after the catalyst and heat exchanger of the ammonia cracker 23 are selected, the corresponding relationship between the two is calibrated through experiments.

[0065] Furthermore, the cracked gas storage pipeline 4 includes a mixed gas buffer tank, a hydrogen flowmeter, and a sixth shut-off valve 20 connected in sequence. The air delivery pipeline includes a first air branch 15 and a second air branch 16. The first air branch 15 is connected to the ammonia-hydrogen premixing pipe 12, and the second air branch 16 is connected to the third ammonia delivery pipe 6 via an air compression pump. The tail gas delivery pipeline also includes a third tail gas branch, which is connected to the first air branch 15 via a seventh shut-off valve 21. The second hydrogenation hot gas pipeline 11 includes a first pipeline and a fourth shut-off valve 22. The second tail gas branch 14 includes a second pipeline and a fifth shut-off valve 25.

[0066] The molar ratio of ammonia and oxygen air supply described above is controlled by an air compression pump to control the air supply, and the ammonia supply is controlled by the ammonia injectors of the corresponding ammonia pipes; the first ammonia pipe 3, the second ammonia pipe 5, the third ammonia pipe 6 and the fourth ammonia pipe 7 are all provided with corresponding ammonia injectors.

[0067] This application also proposes a thermal management method for an on-board ammonia cracking hydrogen production system of an ammonia engine, which includes the following steps:

[0068] S01. Obtain the heating demand type of the on-board ammonia cracking hydrogen production system to derive a corresponding control strategy;

[0069] S02. In response to the control strategy, control the supply of ammonia and oxygen. The specific description is as follows:

[0070] S020: When the heating demand is for the engine cold start condition, the control strategy is:

[0071] According to the gas distribution strategy one, the supply amount of the third ammonia pipeline 6 and the oxygen supply amount of the air delivery pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline 9 can meet the heat required for ammonia cracking in the hydrogen generation pipeline 8, the heat for ignition of the SCR catalyst during cold start of the engine, and the heat required for preheating the ammonia in the first ammonia pipeline 3; the gas distribution strategy one is reaction formula one.

[0072] The hydrogen generated by the hydrogen generation pipeline 8 is transported to the ammonia-hydrogen premixing pipe 12 by using the cracked gas storage pipeline 4 to ignite the ammonia transported by the second ammonia pipeline 5 to complete the engine ignition; at the same time, the exhaust heat of the second exhaust branch 14 preheats the ammonia in the third ammonia pipeline 6.

[0073] S021. When the heat demand is the engine steady-state operating condition, the control strategy is:

[0074] According to gas distribution strategy 2, the supply rate of the third ammonia pipeline 6 and the oxygen supply rate of the air delivery pipeline are controlled so that the heat generated by the ammonia oxidizer heat generation pipeline 9 and the exhaust heat from the first exhaust branch 13 jointly provide heat to the exhaust gas aftertreatment system. Simultaneously, the exhaust heat from the second exhaust branch 14 preheats the ammonia in the third ammonia pipeline 6. Gas distribution strategy 2 is represented by reaction equation 4.

[0075] S022. When the heat supply demand is under high engine load conditions, the control strategy is:

[0076] According to the gas distribution strategy three, the supply rate of the third ammonia delivery pipe 6 and the oxygen supply rate of the air delivery pipe are controlled so that the heat generated by the ammonia oxidizer heat generation pipe 9 can meet the heat required for ammonia cracking in the hydrogen generation pipe 8, the heat required for preheating the ammonia in the first ammonia delivery pipe 3, and the heat required by the second hydrogen oxidation hot gas pipe 11; the gas distribution strategy three is reaction formula three;

[0077] The hydrogen generated by the hydrogen generation pipeline 8 is transported to the ammonia-hydrogen premixing pipe 12 by the cracked gas storage pipeline 4 to ignite the ammonia transported by the second ammonia pipeline 5; at the same time, the exhaust heat of the second exhaust gas branch 14 preheats the ammonia in the third ammonia pipeline 6; the exhaust heat of the first exhaust gas branch 13 and the heat of the second hydrogen oxidation hot gas pipeline 11 jointly provide heat for the exhaust gas after-treatment system, which can replace the DOC unit function of the original after-treatment system.

[0078] Through the above structural setting and thermal management method, the on-board ammonia cracking hydrogen production system of the ammonia engine has the following heat distribution parts:

[0079] Part 1: The liquid ammonia vaporization preheating tank 2 absorbs heat, and the absorbed heat comes from the second tail gas branch 14 and the first hydrogen oxidation hot gas pipeline 10.

[0080] Part 2: Gas distribution and heat release of the ammonia oxidizer heat production pipeline 9; it uses the first ammonia pipe 3 and the second air branch 16 to provide ammonia and oxygen, and reacts with each other to release heat; the released heat participates in the ammonia cracking in the hydrogen generation pipeline 8, and is transmitted to the exhaust gas after-treatment system and the liquid ammonia gasification preheating tank 2.

[0081] Part 3: The hydrogen generation pipeline 8 absorbs heat to crack ammonia into hydrogen, and hydrogen and ammonia participate in the engine ignition and high-load movement of the engine.

[0082] Part 4: The exhaust gas after-treatment system absorbs heat from the first exhaust gas branch 13 and the second hydrogen oxidizing hot gas pipeline 11.

[0083] In summary, the thermal management problem centered on the ammonia oxidizer can be solved, and the ammonia reaction equation in the heat-generating pipeline 9 of the ammonia oxidizer can be prevented from operating in reaction equation 2, thereby avoiding the generation of exhaust pollutants N2O.

[0084] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0085] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0086] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0087] The present application is described with reference to the flow chart and / or block diagram of the method, device (system), and computer program product according to the embodiment of the present application. It should be understood that each flow process and / or box in the flow chart and / or block diagram and the combination of the flow process and / or box in the flow chart and / or block diagram can be realized by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processing machine or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for realizing the function specified in one flow chart flow or multiple flows and / or one box or multiple boxes of the block diagram.

[0088] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0089] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes of the flowchart and / or one or more blocks of the block diagram. In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory. Memory may include non-permanent memory in a computer-readable medium, random access memory (RAM), and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0090] Computer-readable media include permanent and non-permanent, removable and non-removable media that can store information using any method or technology. The information can be computer-readable instructions, data structures, program modules or other data.

[0091] Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory media such as modulated data signals and carrier waves. It should also be noted that the terms "comprises," "comprising," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus. In the absence of more constraints, an element defined by the phrase "comprises a . . . ..." does not preclude the existence of additional identical elements in the process, method, product, or apparatus that comprises the element.

[0092] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. An on-vehicle ammonia cracking hydrogen production system for an ammonia engine, characterized in that: It includes: A liquid ammonia storage tank (1) and a liquid ammonia gasification preheating tank (2) are connected in sequence; the gas outlet end of the liquid ammonia gasification preheating tank (2) is connected to a first ammonia delivery pipe (3), a second ammonia delivery pipe (5), a third ammonia delivery pipe (6) and a fourth ammonia delivery pipe (7); A hydrogen generation pipeline (8), the gas inlet end of which is connected to the first ammonia delivery pipeline (3), and the gas outlet end of which is connected to an ammonia-hydrogen gas channel premixing pipe (12) via a cracked gas storage pipeline (4); the ammonia-hydrogen gas channel premixing pipe (12) is also connected to the second ammonia delivery pipeline (5); an ammonia oxidizer heat generating pipeline (9), which is connected to the third ammonia delivery pipeline (6) and is used to supply heat to the hydrogen generation pipeline (8); the ammonia oxidizer heat generating pipeline (9) is connected to a first hydrogen oxidizing hot gas pipeline (10) and a second hydrogen oxidizing hot gas pipeline (11); the first hydrogen oxidizing hot gas pipeline (10) is used to preheat the ammonia in the first ammonia delivery pipeline (3); An air delivery pipeline, which is used to supply oxygen to the ammonia-hydrogen gas channel premixing pipe (12) and the ammonia oxidizer heat generating pipeline (9), and to control the oxygen delivery amount; The tail gas delivery pipeline comprises a first tail gas branch (13) and a second tail gas branch (14); the second tail gas branch (14) is used to preheat the ammonia in the third ammonia delivery pipeline (6); the first tail gas branch (13) is used to be connected to the air inlet of the tail gas post-treatment system, and the second hydrogen oxidizing hot gas pipeline (11) and the fourth ammonia delivery pipeline (7) are also used to be connected to the air inlet of the tail gas post-treatment system.

2. The vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: The liquid ammonia gasification preheating tank (2) comprises a primary preheating chamber and a secondary preheating chamber which are connected to each other; The primary preheating chamber is in communication with the second tail gas branch (14), and is connected to the third ammonia delivery pipe (6) and the second ammonia delivery pipe (5); The secondary preheating chamber is connected to the first ammonia delivery pipe (3) and the fourth ammonia delivery pipe (7), and the first hydrogen oxidation hot gas pipeline (10) is in communication with the secondary preheating chamber.

3. The vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: The hydrogen generation pipeline (8) comprises a first stop valve (17), an ammonia cracker (23), a cracked gas collection pipe and a second stop valve (18) which are connected in sequence; The ammonia oxidizer heat generating pipeline (9) comprises a third stop valve (19), an ammonia oxidizer (24) and an air outlet pipe which are connected in sequence; heat is exchanged between the ammonia oxidizer (24) and the ammonia cracker (23) via a heat exchanger.

4. The vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: The cracked gas storage pipeline (4) comprises a mixed gas buffer tank, a hydrogen flow meter and a sixth stop valve (20) which are connected in sequence.

5. The vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 1, characterized in that: The air delivery pipeline comprises a first air branch (15) and a second air branch (16); the first air branch (15) is connected to the ammonia-hydrogen gas premixing pipe (12), and the second air branch (16) is connected to the third ammonia delivery pipe (6) via an air compression pump.

6. The vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 5, characterized in that: The exhaust gas delivery pipeline also includes a third exhaust gas branch, which is connected to the first air branch (15) via a seventh stop valve (21).

7. A thermal management method for a vehicle-mounted ammonia cracking hydrogen production system of an ammonia engine as claimed in claim 1, characterized in that: Obtain the heating demand type of the on-board ammonia cracking hydrogen production system to derive the corresponding control strategy; In response to the control strategy, the ammonia and oxygen supply amounts are controlled.

8. The thermal management method of the vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 7, characterized in that: When the heating demand is the engine cold start condition, the control strategy is: According to the first gas distribution strategy, the supply amount of the third ammonia delivery pipe (6) and the oxygen supply amount of the air delivery pipe are controlled so that the heat generated by the ammonia oxidizer heat generation pipe (9) can meet the heat required for ammonia cracking in the hydrogen generation pipe (8), the heat required for the SCR catalyst to be ignited during the cold start of the engine, and the heat required for preheating the ammonia in the first ammonia delivery pipe (3); The hydrogen generated by the hydrogen generation pipeline (8) is transported to the ammonia-hydrogen gas premixing pipe (12) by means of the cracked gas storage pipeline (4) to ignite the ammonia transported by the second ammonia transport pipeline (5) to complete the engine ignition; at the same time, the exhaust heat of the second exhaust branch (14) preheats the ammonia in the third ammonia transport pipeline (6).

9. The thermal management method of the vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 7, characterized in that: When the heating demand is the engine steady-state operating condition, the control strategy is: According to the second gas distribution strategy, the supply amount of the third ammonia delivery pipe (6) and the oxygen supply amount of the air delivery pipe are controlled so that the heat generated by the ammonia oxidizer heat generation pipe (9) and the exhaust heat of the first exhaust gas branch (13) jointly provide heat for the exhaust gas after-treatment system; at the same time, the exhaust heat of the second exhaust gas branch (14) preheats the ammonia in the third ammonia delivery pipe (6).

10. The thermal management method of the vehicle-mounted ammonia cracking hydrogen production system of the ammonia engine according to claim 7, characterized in that: When the heat demand is under high engine load condition, the control strategy is: According to the gas distribution strategy three, the supply amount of the third ammonia delivery pipe (6) and the oxygen supply amount of the air delivery pipe are controlled so that the heat generated by the ammonia oxidizer heat generation pipe (9) can meet the heat required for ammonia cracking in the hydrogen generation pipe (8), the heat required for preheating the ammonia in the first ammonia delivery pipe (3), and the heat required by the second hydrogen oxidation hot gas pipe (11); The hydrogen generated by the hydrogen generation pipeline (8) is transported to the ammonia-hydrogen gas premixing pipe (12) by means of the cracked gas storage pipeline (4) to ignite the ammonia transported by the second ammonia transport pipeline (5); at the same time, the tail gas heat of the second tail gas branch (14) preheats the ammonia in the third ammonia transport pipeline (6); the tail gas heat of the first tail gas branch (13) and the heat of the second hydrogen oxidation hot gas pipeline (11) jointly supply heat to the tail gas post-treatment system.

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