Ammonia hydrogen production coupling biodiesel supply system and operation method

Abstract

The invention discloses an ammonia hydrogen production coupling biodiesel supply system and an operation method, and relates to the technical field of internal combustion engine fuel supply, the supply system comprises a biodiesel tank, the biodiesel tank is connected with a biodiesel injector, and biodiesel is injected into an engine cylinder through the biodiesel injector. According to the ammonia hydrogen production coupling biodiesel supply system and the operation method, in the system starting stage, through cooperation of electric heating and waste heat recovery, the ammonia decomposition reactor rapidly reaches the reaction temperature, and compared with a traditional pure electric heating mode, starting energy consumption is reduced; during low-load driving, the proportion of liquid ammonia is automatically reduced, stratified combustion is formed by hydrogen and biodiesel, and fuel consumption per hundred kilometers is remarkably reduced in cooperation with recovery of air energy by a large-area heat exchanger; during high-load climbing, the ammonia proportion is increased, the reactor is heated through double heat sources to ensure that ammonia is fully decomposed, and the problem of biodiesel power response lag is solved through the high combustion speed of hydrogen.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine fuel supply technology, and in particular to a supply system and operating method for ammonia-to-hydrogen coupled biodiesel. Background Technology

[0002] This has become one of the main causes of the decline in air quality during the morning rush hour in cities. Behind this scenario lies a long-standing technical dilemma faced by traditional diesel engines: when petroleum-based diesel is used as the sole fuel, the high-temperature and oxygen-rich environment during combustion easily leads to the generation of air pollutants, while incomplete combustion produces particulate matter. Even with the addition of an after-treatment system, it is difficult to balance the needs of emission control and power performance.

[0003] To solve this problem, the industry has gradually explored two alternative paths:

[0004] Biodiesel route: As a renewable energy source, biodiesel has a higher oxygen content, which can reduce particulate matter emissions when burned; however, in the actual operation of urban buses, drivers have found that biodiesel burns at a higher temperature than traditional diesel in the summer, which leads to an increase in the emission of certain pollutants, especially when there are frequent starts and stops in congested sections of the road.

[0005] Ammonia-to-hydrogen route: Liquid ammonia is used as a hydrogen storage carrier. The hydrogen produced after decomposition can significantly increase the combustion speed, while nitrogen can dilute the mixture and reduce the combustion temperature. However, in trials on long-haul trucks, ammonia decomposition needs to be carried out at higher temperatures, which requires a large amount of additional electrical energy to heat the reactor when the engine is cold-started. More importantly, when the vehicle climbs a hill and enters a high-load condition, the ammonia decomposition is not complete, and the undecomposed ammonia is discharged with the exhaust gas, which not only has a pungent odor but also corrodes the aftertreatment system.

[0006] The limitations of existing technologies are further amplified in real-world scenarios:

[0007] Significant energy waste: Monitoring data from the logistics park shows that diesel engine exhaust contains a large amount of waste heat, but it is directly discharged into the atmosphere due to the lack of effective recovery devices; and the pressure energy contained in liquid ammonia is also lost through the pressure reducing valve during the process of liquid ammonia dropping from storage pressure to reaction pressure, resulting in unnecessary fuel consumption.

[0008] Poor system coordination: In the mixed fuel test of cold chain transport vehicles, the biodiesel injection amount and the ammonia hydrogen production amount often show a mismatch - the excessive hydrogen at low load leads to unstable combustion, and the insufficient hydrogen at high load leads to a decrease in power. The driver has to make frequent manual adjustments, which seriously affects the operating efficiency.

[0009] Significant safety hazards: An internal report from a chemical industrial park pointed out that the ammonia-to-hydrogen system had repeatedly experienced ammonia concentration exceeding the standard during maintenance due to the lack of real-time concentration monitoring and emergency ventilation linkage, requiring the emergency evacuation of surrounding personnel. Furthermore, the existing fire extinguishing equipment was also inadequate to deal with the special characteristics of fires involving ammonia and biodiesel mixtures.

[0010] These issues all point to a core contradiction: single fuel substitution or simple mixing cannot meet the efficiency, emission, and safety requirements under complex operating conditions, and there is an urgent need for an integrated system that can achieve energy cascade utilization and dynamic coordinated control. Summary of the Invention

[0011] (a) Technical problems to be solved

[0012] To address the shortcomings of existing technologies, this invention provides a supply system and operating method for ammonia-to-hydrogen coupled biodiesel, thereby solving the problems of low ammonia decomposition efficiency, poor system integration, low energy utilization, and insufficient safety in existing technologies.

[0013] (II) Technical Solution

[0014] To achieve the above objectives, the present invention provides the following technical solution:

[0015] A supply system for ammonia-to-hydrogen coupled with biodiesel.

[0016] This system achieves efficient energy utilization and emission optimization through the coordinated operation of four core components: biodiesel supply, liquid ammonia supply, ammonia-to-hydrogen conversion, mixing and control, and a safety auxiliary module. Each component forms a closed-loop control system using the following formulas:

[0017] The biodiesel supply system consists of a biodiesel tank, a biodiesel pump, and a multi-nozzle biodiesel injector. The biodiesel tank is connected to the multi-nozzle biodiesel injector via a delivery pump and a high-pressure common rail. This injector injects biodiesel into the engine combustion cylinders, with the injection timing and pressure controlled by an electronic control unit (ECU). The biodiesel tank is equipped with a level monitoring device that triggers a replenishment warning when the level falls below a preset lower limit L1. The biodiesel injection quantity Q... BD With engine power demand P engine and real-time hydrogen production The correlation formula is:

[0018] ;

[0019] Where, η BD For biodiesel combustion efficiency, H BD The low calorific value of biodiesel, where α is the hydrogen substitution coefficient. To maximize hydrogen production, this formula ensures a stable total energy output;

[0020] Liquid ammonia supply section: includes a liquid ammonia storage tank, a liquid ammonia pump, and a pressure-controlled injection device (liquid ammonia injector); the liquid ammonia storage tank is connected to the pressure-controlled injection device via the liquid ammonia pump, which is installed at the inlet of the ammonia decomposition reactor; it is also equipped with an ammonia content detection device (ammonia concentration sensor), an emergency shut-off valve, and a pressure monitoring device. When the ammonia content exceeds the specified standard C1 or the pressure is abnormal, the emergency shut-off valve automatically stops the liquid ammonia supply; liquid ammonia supply volume... With biodiesel injection quantity Q BD The energy distribution relationship is as follows:

[0021] ;

[0022] in, β is the heat of combustion of ammonia, and β is the energy distribution coefficient. The electronic control device dynamically adjusts the value of β according to the engine load so that β∈[β1,β2] under low load and β∈[β3,β4] under high load (β1<β2<β3<β4). This can be preset.

[0023] The ammonia-to-hydrogen conversion process: The ammonia decomposition reactor has a corrosion-resistant metal shell and an internal honeycomb ceramic support structure with catalytic substances attached to it. The outer layer of the reactor is equipped with finned pipes to recover the residual heat from the exhaust gas from the biodiesel supply section. The inner layer is equipped with electric heating elements (i.e., electric heating devices) for heating during system startup. Heat conduction components and temperature sensors are installed inside to ensure that the temperature difference between different parts of the reaction bed does not exceed the set range ΔT.

[0024] Hydrogen production from ammonia decomposition reaction The relationship between the reaction temperature T and the catalytic activity A is as follows:

[0025] ;

[0026] Where k0 is the reaction rate constant, E is the activation energy of the reaction, and R is the gas constant. The ammonia concentration is given; the heat balance equation for the reactor is:

[0027] Q electrical +Q waste =Q reaction +Q loss ;

[0028] Among them, Q electrical The heat provided by the electric heating element, Q waste To recover waste heat from exhaust gas, Q reaction Q is the heat required for the ammonia decomposition reaction. loss To mitigate heat loss, the electric heating power is adjusted in real time using this equation to maintain the reaction temperature.

[0029] The mixing and control section includes a Venturi mixer and an intake manifold flow regulator. The mixer premixes hydrogen and nitrogen with air before sending the mixture into the combustion cylinder (engine cylinder) through the intake manifold. It also includes an electronic control unit, a microcomputer with built-in fuzzy control algorithms and a working condition database, which achieves optimized system control through the following formula chain:

[0030] Dynamic balance coefficient K (for evaluating overall system efficiency):

[0031] ;

[0032] In the formula, For ammonia decomposition efficiency, To maximize the hydrogen production power, parameters K are adjusted.

[0033] Air-fuel ratio λ (to ensure combustion efficiency):

[0034] ;

[0035] Among them, Q air For airflow, For hydrogen flow rate, γ air The oxygen content coefficient of air. γ is the oxygen demand coefficient for hydrogen combustion. BD The oxygen demand coefficient for biodiesel combustion is determined by adjusting the air flow rate Q. air To keep λ within the optimal range [λ1, λ2], a pre-defined setting is used;

[0036] Safety auxiliary module: includes explosion-proof device, fire extinguishing device and emergency ventilation system; explosion-proof device is installed in ammonia hydrogen production module and liquid ammonia storage area; fire extinguishing device is linked to temperature sensor and automatically activates when fire is detected;

[0037] The relationship between the ventilation volume V of the emergency ventilation system and the ammonia concentration C is as follows:

[0038] ;

[0039] In the formula, k4 is the ventilation coefficient, C2 is the safe concentration, and P system For system pressure, P atm For atmospheric pressure, P ref The reference pressure is used to ensure that harmful gases are discharged quickly.

[0040] Preferably, the biodiesel tank of the biodiesel supply section is made of corrosion-resistant material and has a leak-proof structure and insulation layer; the output pressure P of the biodiesel pump is not lower than the preset high pressure value P1 and is equipped with a pressure stabilizing device;

[0041] The multi-nozzle biodiesel injector's nozzle orifice diameter conforms to the micro-orifice standard d1, supports multiple injections, and its pre-injection volume Q pre With main injection volume Q main The relationship is:

[0042] ;

[0043] Where r8 is the pre-spray ratio, k pre ΔP is the load correction factor. engine P is the change in power. engine,base Using the base power, this formula enables dynamic adjustment of the pre-injection amount according to the load.

[0044] Preferably, the liquid ammonia storage tank in the liquid ammonia supply section adopts a double-layer vacuum insulation structure to maintain the storage of liquid ammonia at a low temperature. The container is equipped with an external heat insulation protective layer and a vacuum monitoring device; the liquid ammonia pump output pressure With reactor inlet pressure P reactor The relationship is:

[0045] ;

[0046] Where, ΔP pump ρ is the pump head, g is the density of liquid ammonia, h is the gravitational acceleration, and h is the conveying height, ensuring that liquid ammonia can overcome system resistance and enter the reactor.

[0047] Preferably, in the ammonia-to-hydrogen conversion process, the pore density of the honeycomb ceramic support structure meets a preset density standard ρ1, the loading of the catalyst is gradient-distributed along the reactor axis, and the inlet loading A... in With output load A out The relationship is:

[0048] A in =A out ×(1+δ);

[0049] Where δ is the gradient coefficient (15%≤δ≤20%), this distribution affects the ammonia decomposition efficiency. satisfy:

[0050] ;

[0051] Where η0 is the baseline efficiency, T is the reaction temperature, and T ref The reference temperature is used to maximize catalytic efficiency.

[0052] Preferably, the venturi mixer in the mixing and control section is equipped with a pressure balancing valve, whose adjustment ΔP balance The formula is:

[0053] ;

[0054] Among them, P mix For the mixed pressure, P target For target pressure, k p k i k d The system uses PID control parameters to ensure stable mixed air pressure; a flow meter and check valve are installed on the intake pipe to prevent gas backflow; the electronic control unit is connected to a human-machine interface, which can display system operating parameters and fault information, and supports manual parameter adjustment.

[0055] An operating method for an ammonia-to-hydrogen coupled biodiesel supply system includes the following steps:

[0056] The electronic control unit performs a self-check on the entire system, including parameters such as the status of each component, liquid level, pressure, and concentration. Upon successful self-check, the biodiesel pump is activated, injecting pure biodiesel at a preset starting pressure P4 for a cold start, continuing for a preset starting time t1. Simultaneously, the electric heating element raises the reactor temperature to the preset reaction initiation temperature T1 at maximum output power, and the liquid ammonia pump is activated, with the initial liquid ammonia injection amount being a preset initial ratio r1 of the biodiesel mass. The heat required for heating is Q. heat The calculation formula is:

[0057] Q heat =m×c p ×(T1-T initial )+Q reaction_init ;

[0058] Where m is the reactor mass, c p For specific heat capacity, T initial Q is the initial temperature. reaction_init This is the heat required for the decomposition reaction in the initial stage;

[0059] Under low load conditions (≤30%): the proportion of liquid ammonia is within the preset first ratio range [r2, r3]. A mixture of hydrogen and nitrogen is injected through the inlet pipe, forming stratified combustion with biodiesel. The reactor temperature is maintained within the preset first temperature range [T2, T3]. (Using the formula:)

[0060] ;

[0061] Dynamically adjust the liquid ammonia supply (k3 is the adjustment coefficient, η) current For the current decomposition efficiency, P engine For engine power requirements, P max (for rated power), ensuring that the decomposition efficiency reaches η1;

[0062] Medium load condition (30%~70%): The proportion of liquid ammonia is in the preset second ratio range [r4,r5], switch to direct injection and premixed combustion in the cylinder, and the reactor temperature is maintained in the preset second temperature range [T4,T5]; start the dual-cycle thermal management mode, and distribute the cylinder waste heat and exhaust waste heat to the ammonia decomposition device and biodiesel preheating stage according to the preset ratio k3.

[0063] Under high load conditions (>70%): the proportion of liquid ammonia is within the preset third ratio range [r6, r7]. Increase the reactor heating power to ensure that the ammonia decomposition ratio exceeds the second efficiency value η2; the adjustment formula for the biodiesel pre-injection ratio r8 is:

[0064] ;

[0065] Where, r 8_base Based on the pre-spray ratio, k load This is the load adjustment coefficient;

[0066] Shutdown Phase: The electronic control unit gradually reduces the liquid ammonia injection rate until it stops, while continuing to deliver biodiesel for a preset shutdown duration of t2. Residual ammonia is decomposed using residual heat from the exhaust gas. The residual ammonia decomposition time is t. clear The calculation formula is:

[0067] ;

[0068] Among them, C residual k represents the residual ammonia concentration. clear T is the decomposition rate coefficient. exhaust P is the exhaust temperature. engine_final The power level before shutdown; after reaching a safe concentration, shut down the delivery pump and heating device, and start the system cleaning program to purge the spraying device and pipelines.

[0069] Preferably, the process also includes a complete process for recycling residual heat: the high-temperature mixed gas generated in the ammonia-to-hydrogen conversion process is first preheated to biodiesel by a first waste heat recovery device, raising its temperature to a preset preheating range [T7, T8]; the cooled mixed gas enters the engine for combustion, and the exhaust gas after combustion drives a micro-generator to generate electricity through a second waste heat recovery device. The electricity is preferentially supplied to the electronic control device, induction device, and heating element in the system, and the remaining electricity is stored in a backup energy storage device; the residual heat of the exhaust gas after power generation is used to assist in heating the reactor through a third waste heat recovery device, with a waste heat recovery efficiency η. waste The calculation formula is:

[0070] ;

[0071] Among them, Q recovered1 Q recovered2 Qrecovered3 The heat recovered by the three waste heat recovery devices, Q exhaust_total For the total exhaust heat, T ambient For ambient temperature, T exhaust_avg To achieve the average exhaust temperature, the electronic control unit adjusts the waste heat distribution ratio using this formula to maximize η. waste .

[0072] Preferably, the explosion-proof device of the safety auxiliary module includes a pressure relief valve and a flame detector. When an explosion risk or flame is detected, the pressure relief valve quickly releases pressure and simultaneously closes the emergency shut-off valve. The fire extinguishing device uses a fire extinguishing medium suitable for extinguishing liquid fuel and gas fires and is linked to the system power supply. It automatically cuts off unnecessary power during fire extinguishing. The ventilation volume of the emergency ventilation system can be automatically adjusted according to the ammonia concentration to ensure that the concentration of harmful gases is quickly reduced to below the safe value.

[0073] Preferably, the system operation also includes dynamic diagnosis and fault tolerance steps: the electronic control device continuously compares the real-time data of each sensor with the standard parameter range, and initiates parameter self-calibration when a slight deviation occurs; when a component failure is detected, the corresponding fault tolerance strategy is activated according to the fault level, such as enabling redundant sensor data when a single sensor fails, and automatically switching to emergency operation mode to reduce the load and issue maintenance prompts when a critical component fails; fault records are automatically stored and can be queried through the human-machine interface, and the formula for calculating the fault diagnosis accuracy A is:

[0074] ;

[0075] Where, N correct N is the number of correct diagnoses. total This represents the total number of diagnoses.

[0076] Preferably, the system also includes an environmental adaptation module, which includes an ambient temperature sensor and an altitude sensor. The electronic control device adjusts the preheating time and heating power according to the ambient temperature, and corrects the air-fuel mixture ratio according to the altitude. The environmental correction coefficient K is... env The calculation formula is:

[0077] ;

[0078] Where k5 is the temperature coefficient, k6 is the altitude coefficient, k7 is the air density coefficient, and T env Here, H represents ambient temperature, and ρ represents altitude. air ρ is the air density. air_ref This coefficient, used as a reference for air density, is used to correct the biodiesel injection quantity, liquid ammonia supply, and air flow rate, ensuring that the system can maintain the preset operating efficiency under different environmental conditions.

[0079] (III) Beneficial Effects

[0080] This invention, through systematic integrated design and dynamic control strategies, demonstrates significant advantages in actual operation. The implementation process of its technical solution is deeply intertwined with its beneficial effects, as detailed below:

[0081] 1. During the system startup phase, the ammonia decomposition reactor is rapidly brought to the reaction temperature through the synergy of electric heating and waste heat recovery (external finned tubes recover exhaust heat + internal electric heating assistance), reducing startup energy consumption compared to traditional pure electric heating methods; after entering stable operation, the dynamic ratio mechanism of biodiesel and ammonia to hydrogen production begins to play its role:

[0082] When driving under low load (such as in congested urban areas), the proportion of liquid ammonia automatically decreases, and hydrogen and biodiesel form stratified combustion. Combined with the large-area heat exchanger to recover air energy, this significantly reduces fuel consumption per 100 kilometers.

[0083] During high-load ramp-up, the proportion of ammonia increases. The reactor uses dual heat sources (waste heat + electric assistance) to ensure the full decomposition of ammonia. The high combustion speed of hydrogen compensates for the lag in the power response of biodiesel. At the same time, the dilution effect of nitrogen reduces the combustion temperature and reduces nitrogen oxide emissions. Through the optimized control of the dynamic balance coefficient K throughout the process, the overall energy utilization rate of the system is significantly improved and carbon dioxide emissions are greatly reduced, perfectly meeting the city's requirements for energy conservation and emission reduction of commercial vehicles.

[0084] 2. When the vehicle travels from the plains to the plateau, the environmental adaptation module uses the altitude sensor to correct the air-fuel ratio in real time, adjusting the air-fuel mixture to the optimal ratio, thus avoiding the power loss caused by lack of oxygen in traditional systems.

[0085] When faced with sudden acceleration demands, the electronic control unit increases the supply of liquid ammonia in advance through a load prediction model, while adjusting the pre-injection ratio of biodiesel to improve the engine torque response speed, thus solving the industry pain point of "lag" in hybrid fuel systems.

[0086] This all-condition adaptive adjustment mechanism allows drivers to obtain stable power output without manual intervention, significantly improving one-way transportation efficiency in scenarios with high timeliness requirements, such as cold chain transportation.

[0087] 3. When a simulated ammonia leak occurs, the ammonia concentration sensor quickly detects the excessive signal, the emergency shut-off valve immediately shuts off the liquid ammonia supply, and the emergency ventilation system automatically adjusts the air volume according to the concentration, reducing the leak concentration to below the safe value in a short time, avoiding the delay risk of traditional systems that require manual shutdown.

[0088] During fire extinguishing tests, the special fire extinguishing medium can quickly control the fire in the case of a mixture of ammonia and biodiesel, and the system automatically cuts off unnecessary power to prevent secondary accidents.

[0089] In addition, the residual ammonia removal procedure during shutdown uses exhaust waste heat to continuously decompose residual ammonia, ensuring the safety of operators during maintenance and completely eliminating the "worries" about the ammonia-to-hydrogen system.

[0090] 4. The high-temperature mixed gas generated by the ammonia-to-hydrogen module preheats the biodiesel to improve its fluidity and reduce injection blockage problems caused by low temperatures in winter;

[0091] Waste heat from exhaust gas drives a micro gas turbine to generate electricity, meeting part of the electricity demand of the on-board refrigeration unit, reducing the impact on engine power, and indirectly reducing fuel consumption.

[0092] Ultimately, the remaining heat is returned to the reactor for auxiliary heating, shortening the working time of the electric heating element and extending the life of the components.

[0093] This closed-loop design of "hydrogen production - combustion - power generation - reheating" allows energy to be utilized in stages within the system, achieving the goal of "making full use of every resource". Attached Figure Description

[0094] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0095] Figure 1 This is an overall structural diagram of the system according to an embodiment of the present invention;

[0096] Figure 2 This is an overall flowchart of an embodiment of the present invention.

[0097] Explanation of reference numerals in the attached figures:

[0098] 11. Biodiesel tank; 12. Biodiesel pump; 13. Biodiesel injector; 14. Engine cylinder; 15. Filter; 16. High-pressure common rail;

[0099] 21. Liquid ammonia storage tank; 22. Liquid ammonia pump; 23. Liquid ammonia injector; 24. Emergency shut-off valve;

[0100] 31. Ammonia decomposition reactor; 32. Electric heating device; 33. Ammonia concentration sensor; 34. Waste heat boiler; 35. Inlet manifold;

[0101] 4. Mixer;

[0102] 5. ECU. Detailed Implementation

[0103] This application provides a supply system and operation method for ammonia-to-hydrogen coupled with biodiesel to address the problems of low ammonia decomposition efficiency, poor system integration, low energy utilization, and insufficient safety in existing technologies. During system startup, the system utilizes a combination of electric heating and waste heat recovery—specifically, the outer finned tube recovers exhaust heat while the inner electric heating assists—to quickly bring the ammonia decomposition reactor to the reaction temperature, reducing startup energy consumption compared to traditional pure electric heating methods. Once stable operation is achieved, the dynamic ratio mechanism of biodiesel to ammonia-to-hydrogen begins to function: under low-load conditions (such as in congested urban areas), the proportion of liquid ammonia... Automatic reduction in fuel consumption per 100 kilometers is achieved through stratified combustion of hydrogen and biodiesel, coupled with the recovery of air energy by a large-area heat exchanger. During high-load uphill driving, the proportion of ammonia increases, and the reactor ensures the full decomposition of ammonia through dual heat source heating (waste heat + electric assistance). The high combustion speed of hydrogen compensates for the lag in power response of biodiesel, while the dilution effect of nitrogen reduces the combustion temperature and decreases nitrogen oxide emissions. Through optimized control of the dynamic balance coefficient K throughout the process, the overall energy utilization rate of the system is significantly improved, and carbon dioxide emissions are greatly reduced, perfectly meeting the energy conservation and emission reduction requirements of cities for commercial vehicles.

[0104] With the global energy crisis and environmental problems becoming increasingly severe, the need for energy conservation and emission reduction in internal combustion engines, as the main power source, is becoming more and more urgent. Traditional diesel engines use petroleum-based diesel fuel, which produces large amounts of carbon dioxide and nitrogen oxides (NOx) during combustion. x The presence of particulate matter (PM) makes it difficult to meet increasingly stringent emission regulations; biodiesel, as a renewable fuel, has the advantages of high oxygen content and low sulfur content, but its high combustion temperature leads to increased NOx emissions. x Increased emissions; liquid ammonia, as an ideal hydrogen storage carrier, can improve combustion speed with the hydrogen produced after decomposition, and nitrogen can dilute and reduce combustion temperature. However, ammonia decomposition requires high-temperature conditions, typically >600℃, and there is a risk of incomplete decomposition leading to ammonia leakage. In existing technologies, the integrated application of ammonia-to-hydrogen and biodiesel faces three major bottlenecks: first, the ammonia decomposition efficiency is low and cannot be dynamically adjusted according to engine operating conditions; second, the system integration is poor, energy matching is insufficient, and hydrogen resources in the exhaust gas are not effectively utilized; and third, there is a lack of all-condition safety control strategies, making it difficult to adapt to complex environmental conditions. To address these issues, this paper proposes a supply system and operation method for ammonia-to-hydrogen coupled with biodiesel, achieving efficient and clean combustion through multi-module collaborative control and energy cascade utilization.

[0105] Example: The technical solutions in this application address the problems of low ammonia decomposition efficiency, poor system integration, low energy utilization, and insufficient safety in the prior art. The overall approach is as follows:

[0106] To address the problems existing in the prior art, this invention provides an ammonia-to-hydrogen coupled biodiesel supply system. The ammonia-to-hydrogen coupled biodiesel supply system adopts a "four-core + one auxiliary" architecture design. Each module forms a closed-loop control through parameter transmission and formula calculation. The overall architecture includes a biodiesel supply section, a liquid ammonia supply section, an ammonia-to-hydrogen processing section, and a mixing and control section, supplemented by a safety auxiliary module, to realize full-process management of fuel supply, conversion, combustion and safety assurance.

[0107] The biodiesel supply section consists of a biodiesel tank 11, a biodiesel pump 12, and a multi-nozzle biodiesel injector 13. A filter 15 is installed on the pipeline between the biodiesel tank 11 and the biodiesel pump 12 to filter gaseous impurities. The biodiesel tank 11 is connected to the biodiesel injector 13 through the biodiesel pump 12 and a high-pressure common rail 16. The storage tank is made of 304 stainless steel and has a double-layer leak-proof structure and insulation layer. The volume is matched according to the engine power. It is equipped with an ultrasonic level sensor. When the liquid level is lower than the preset lower limit value of 20% of the volume, an audible and visual replenishment prompt is triggered. The biodiesel pump 12 adopts a plunger structure, and the outlet pressure can be adjusted within the range of 160-200MPa with a pressure fluctuation of ≤±2%. The pressure is closed-loop controlled by an electromagnetic proportional valve. The mixer 4 can premix the mixture of hydrogen and nitrogen with air and send it into the combustion cylinder (engine cylinder 14) through the intake pipe.

[0108] The multi-nozzle biodiesel injector 13 adopts a 6-hole design with nozzle orifice diameters of 0.1 to 0.3 mm. It supports 3 injections: pre-injection, main injection, and post-injection. The injection timing and pressure are controlled by an electronic control unit (ECU5) through a high-speed solenoid valve.

[0109] The biodiesel injection quantity needs to be dynamically adjusted based on engine power requirements and hydrogen production from ammonia-to-hydrogen conversion. The calculation formula is as follows:

[0110] ;

[0111] In the formula, Q BD This refers to the biodiesel injection rate, expressed in kg / h, P. engine For engine power requirements, in kW, η BD For biodiesel combustion efficiency, a value of 0.85-0.9 is generally used. BD It has a low calorific value of biodiesel, approximately 42 MJ / kg, and α is the hydrogen substitution factor (0.3-0.5). This represents real-time hydrogen production, expressed in kg / h. The maximum hydrogen production is expressed in kg / h. This formula dynamically adjusts biodiesel consumption based on hydrogen production to ensure stable total energy output.

[0112] The liquid ammonia supply system adopts a -33℃ cryogenic storage scheme. The liquid ammonia storage tank 21 is made of 16MnDR cryogenic steel with a volume of 30-60L. It has a double-layer vacuum insulation structure with a vacuum degree of ≤1Pa. The interlayer is filled with perlite insulation material with a thermal conductivity of ≤0.03W / (m・K). A platinum resistance temperature sensor and a pressure transmitter are installed on the outside of the container to monitor the operating parameters in real time. The cryogenic liquid ammonia pump 22 is a magnetically driven centrifugal pump with a flow range of 0.5-5L / h and an outlet pressure of 1.5-2.5MPa. It is equipped with a mass flow controller and realizes closed-loop flow control through a PID algorithm.

[0113] This includes a -33℃ cryogenic liquid ammonia storage tank 21, a cryogenic liquid ammonia pump 22, a pressure-type liquid ammonia injector 23 installed at the reactor inlet, and an ammonia concentration sensor 33 with a detection limit of 50ppm that is linked to an emergency shut-off valve 24 to automatically cut off the liquid ammonia supply when the limit is exceeded.

[0114] A pressure-controlled injection device is installed at the inlet of ammonia decomposition reactor 31, using a pneumatic nozzle with an injection angle of 60° and an atomized particle size ≤50μm. System safety design includes: an ammonia concentration sensor 33 linked to an emergency shut-off valve; a level one warning is triggered when the ammonia concentration exceeds 25ppm, and the supply is automatically cut off when it exceeds 50ppm; a pressure monitoring device activates a pressure relief valve when the system pressure exceeds 3MPa, with a release rate of 50L / min; the energy distribution relationship between liquid ammonia and biodiesel is as follows:

[0115] ;

[0116] In the formula, β is the energy distribution coefficient (0.05-0.3). This refers to the supply rate of liquid ammonia, expressed in kg / h. The heat of combustion of ammonia is 18.6 MJ / kg. ECU5 dynamically adjusts the β value according to the engine load. For low load (≤30%), the value is 0.05-0.1, and for high load (>70%), the value is 0.2-0.3.

[0117] The ammonia decomposition reactor uses a 316L stainless steel shell; the internal core is a cordierite honeycomb ceramic carrier with a pore density of 400-600 cpsi and a coefficient of thermal expansion ≤1.5×10⁻⁶. -6 The reactor is equipped with a catalyst at a temperature of ℃, loaded with 0.5% Ru / Al2O3, with the loading rate gradient along the axial direction: 2.5 g / L at the inlet and 2.1 g / L at the outlet to match the decreasing ammonia concentration. The outer layer of the device is wound with spiral finned tubes for recovering exhaust heat from the engine (300-600℃). The inner layer incorporates nickel-chromium electric heating wires for heating during cold starts. An internal microchannel heat-conducting plate, coupled with distributed Pt100 temperature sensors (≥5 measurement points), ensures a temperature difference of ≤±5℃ between reaction beds. The hydrogen production from the ammonia decomposition reaction is closely related to the reaction conditions; the kinetic equation is as follows:

[0118] ;

[0119] In the formula, Let be the amount of hydrogen produced by the ammonia decomposition reaction, and k0 be the reaction rate constant, taken as 1.2 × 10⁻⁶. 6 A is the catalyst activity factor (0.8-1.0), E is the activation energy of the reaction (approximately 30 kJ / mol), R is the gas constant (8.314 J / (mol·K)), and T is the reaction temperature in K. Ammonia concentration, unit: mol / m³ 3 .

[0120] To maintain a stable reaction temperature, the heat balance equation is:

[0121] Q electrical +Q waste =Q reaction +Q loss ;

[0122] In the formula, Q electrical Electric heating power, unit: kW, Q waste The recovered waste heat is expressed in kW (Q). reaction The endothermic rate of the ammonia decomposition reaction is expressed in kW and Q. loss The heat loss is approximately 5% to 10%. By adjusting the ratio of electric heating power to waste heat distribution, the reaction temperature is ensured to remain stable at 450-550℃.

[0123] The mixing unit adopts a venturi structure, premixing the H2 / N2 mixture generated by ammonia decomposition with air at a volume ratio of 2:1. The premixed gas is then sent into the combustion chamber via the intake manifold 35 or direct injection into the cylinder. Simultaneously, the intake manifold 35 is connected to the waste heat boiler 34, which can preheat the mixed gas. The intake pipeline is equipped with an electromagnetic flow valve and a check valve to prevent gas backflow. The electronic control unit uses a 32-bit STM32H743 microcontroller with a built-in fuzzy PID algorithm and operating condition database, storing 1000+ typical operating condition parameters, a sampling frequency ≥1kHz, and a control cycle ≤10ms.

[0124] By collecting signals from 16 sensors, including engine speed, load, cylinder temperature, and air-fuel mixture concentration, the system outputs 12 control signals in real time, including injector drive and heating power adjustment. The core control parameters of the system include the dynamic balance coefficient K (to assess overall system efficiency) and the air-fuel ratio λ (to ensure combustion efficiency), calculated using the following formulas:

[0125] ;

[0126] ;

[0127] In the formula, Ammonia decomposition efficiency, in percentage. Hydrogen generation power, in kW, target value K opt =1.2±0.1; Q air For airflow, For hydrogen flow rate, γ air Oxygen content in the air γ is the oxygen demand coefficient for hydrogen combustion. BD γ is the oxygen demand coefficient for biodiesel combustion. air =0.23, =0.5, γ BD =14.5, control range λ=1.05-1.15, optimal combustion range.

[0128] The safety auxiliary module includes a triple protection mechanism: the explosion-proof device consists of a rupture disc (burst pressure 3.5MPa) and a flame detector; when a flame or overpressure is detected, the rupture disc ruptures to release pressure, simultaneously closing the emergency shut-off valve; the fire extinguishing device uses an ABC dry powder fire extinguisher, linked to a temperature sensor (detection range -50-1000℃); it automatically activates when the detected local temperature exceeds 80℃ and the rate of increase is >10℃ / s, simultaneously cutting off unnecessary power; the axial flow fan of the emergency ventilation system is linked to an ammonia concentration sensor 33, and the ventilation volume is dynamically adjusted according to the ammonia concentration.

[0129] ;

[0130] In the formula, V is the ventilation volume of the emergency ventilation system, C is the ammonia concentration, k4 is the ventilation coefficient, C2 is the safe concentration, and P system For system pressure, P atm For atmospheric pressure, P ref For reference pressure, k4=0.8, C2=25ppm, P ref =0.1MPa, ensuring that the ammonia concentration drops below the safe level within 30 seconds.

[0131] Running method

[0132] The system operation is divided into the startup phase, the dynamic load adjustment phase, and the shutdown phase, and runs through the waste heat recycling process. Efficient and safe operation is achieved through full-condition parameter optimization.

[0133] During the 0-60s startup phase, the system first performs a self-test: After ECU5 is powered on, it initializes and tests the sensors and actuators. If a fault is found (such as a sensor disconnection or valve jamming), a fault code is sent via the CAN bus and a warning light is illuminated.

[0134] After passing the self-test, biodiesel pump 12 injects pure biodiesel at a pressure of 160 MPa for 5–10 seconds to achieve a cold start of the engine, maintaining an initial speed of 800 ± 50 r / min. Simultaneously, the electric heating element is activated to raise the temperature of ammonia decomposition reactor 31 from ambient temperature to 450℃ at a rate of 5–8℃ / s. The heat required for this temperature rise is Q. heat :

[0135] Q heat =m×c p ×(T1-T initial )+Q reaction_init ;

[0136] In the formula, m is the reactor mass, and c p T represents the specific heat capacity of stainless steel, T1 is the preset reaction initiation temperature, and T... initial Q represents the ambient temperature. reaction_init The reaction is endothermic during the start-up phase, m = 20 kg, c p =450J / (kg·K), T1=450℃, Q reaction_init =1.2kW.

[0137] When the reactor temperature reaches 450℃, the liquid ammonia pump is started, with the initial ammonia supply being 5% of the biodiesel mass, and gradually increased to a stable value through the flow controller.

[0138] The load dynamic adjustment phase is divided into three adjustment ranges based on engine load detected by a throttle position sensor or torque sensor:

[0139] At low load (≤30%, speed ≤1500 r / min), liquid ammonia accounts for 5%–10% of the energy ratio, and biodiesel accounts for 90%–95%. The H2 / N2 mixture is injected through the intake manifold at 35°C, 120°CA before top dead center of the intake stroke, forming stratified combustion with the biodiesel. Hydrogen is in the upper part of the cylinder, and biodiesel is in the lower part. The reactor temperature is maintained at 450–500℃. By adjusting the proportion of waste heat recovery from the exhaust gas, which accounts for 60%–70% of the total heat, the consumption of electric heating is reduced. The decomposition efficiency is improved by using a liquid ammonia supply correction formula.

[0140] ;

[0141] In the formula, k3 is the adjustment coefficient, η1 is the target efficiency, and η current For current efficiency, P engine For engine power requirements, P max Given the rated power, k3=0.8, η1=90%.

[0142] At medium load (30%–70%, speed 1500–3000 r / min), liquid ammonia accounts for 10%–20%, and biodiesel accounts for 80%–90%. The system switches to in-cylinder direct injection premixed combustion. The H2 / N2 mixture is injected 60°CA before top dead center of the compression stroke. Biodiesel adopts a "pre-injection + main injection" strategy. The pre-injection amount accounts for 10%–15%, and the injection time is 30°CA before top dead center. The reactor temperature is maintained at 500–550℃. The dual-cycle thermal management mode is activated. The cylinder waste heat (80–90℃) and exhaust waste heat (300–400℃) are distributed to the ammonia decomposition unit and biodiesel preheating in a 3:7 ratio, heating the biodiesel from 25℃ to 40℃.

[0143] At high loads (>70%, speed >3000 r / min), liquid ammonia accounts for 20%–30%, biodiesel accounts for 70%–80%, the pre-injection ratio of biodiesel is increased to 15%–20%, the pre-injection time is 40°CA before top dead center, and the main injection time is advanced to 15°CA before top dead center. The formula for calculating the pre-injection amount is as follows:

[0144] ;

[0145] In the formula, r8 is the pre-injection ratio of biodiesel, r 8_base Based on the pre-spray ratio, k load r is the load regulation coefficient. 8_base =15%, k load =0.5, the reactor temperature is maintained at 550℃, and the electric heating power is increased to 3-5kW; when the reactor temperature exceeds 580℃, the liquid ammonia supply is automatically reduced by 5% to 10%, and the proportion of biodiesel is increased.

[0146] During the shutdown phase (120-180s), after receiving the shutdown signal, ECU5 linearly reduces the liquid ammonia supply to 0 within 10s, while maintaining a stable biodiesel supply. Biodiesel production continues for 1-2 minutes, utilizing exhaust waste heat (200-300℃) to decompose residual ammonia in the reactor. The residual ammonia decomposition time... :

[0147] ;

[0148] In the formula, C residual (initial residual concentration), k clear T is the decomposition rate coefficient. exhaust P is the exhaust temperature. engine_final C represents the power before shutdown. residual =500ppm, k clear =0.02ppm / (s·℃), T exhaust =250℃.

[0149] When the ammonia concentration sensor 33 detects a residual ammonia concentration ≤5ppm, the biodiesel pump 12 and the electric heating device 32 are shut down, and the compressed air purging program is started at 0.6MPa for 30 seconds to remove residual fuel from the injectors and pipelines. The ECU5 saves the operation data, including fuel consumption, emission indicators, fault records, etc., to local storage and completes the shutdown sequence.

[0150] Waste heat recycling adopts a three-stage recovery scheme:

[0151] In the primary waste heat recovery process, the high-temperature mixed gas produced by ammonia decomposition enters a shell-and-tube heat exchanger to exchange heat with biodiesel, heating the biodiesel from ambient temperature to 30-40°C, recovering approximately 15-20 kW of heat, and reducing the viscosity of the biodiesel from 80 mm. 2 / s decreased to 40mm 2 / s, to improve the atomization effect;

[0152] In the secondary waste heat recovery, the cooled air-fuel mixture (400-500℃) enters the engine for combustion, and the exhaust gas (300-400℃) drives a micro gas turbine to generate electricity. The electricity is preferentially supplied to ECU5, sensors and electric heating elements, and the remaining electricity is stored in a lithium-ion battery.

[0153] In the three-stage waste heat recovery process, the exhaust gas (150-200℃) after the gas turbine passes through a finned heat exchanger to provide auxiliary heating for the ammonia decomposition reactor 31, recovering approximately 5-8 kW of heat and reducing electric heating energy consumption. The overall waste heat recovery efficiency is... The calculation formula is:

[0154] ;

[0155] In the formula, Q recovered1 For primary heat recovery, Q recovered2 For secondary heat recovery, Q recovered3 For three-stage heat recovery, Q exhaust_total For the total exhaust heat, T ambient Ambient temperature, in K and T. exhaust_avg Q is the average exhaust temperature. recovered1 =15-20kW, Q recovered2 =5-10kW, Q recovered3 =5-8kW, Q exhaust_total =60-80kW, T exhaust_avg =500K.

[0156] The system achieves parameter self-correction under different operating conditions through an environment adaptation module, the core of which is the environment correction coefficient K. env Calculation:

[0157] ;

[0158] In the formula, k5 is the temperature coefficient, k6 is the altitude coefficient, k7 is the air density coefficient, and T env Ambient temperature (°C), H altitude (m), ρ air Local air density, unit: kg / m³ 3 , ρ air_ref Standard air density; K env Used to correct biodiesel injection rate, liquid ammonia supply, and airflow rate, k5=-0.002, k6=-0.0001, k7=0.5, ρ air_ref =1.225kg / m 3 For example, in a high-altitude environment, at an altitude of 3000m, the air density is 0.88kg / m³. 3 K env =0.85, the system automatically reduces fuel supply by 15% and increases airflow by 20% to compensate for combustion losses in a low-oxygen environment.

[0159] Dynamic diagnostics and fault-tolerant control employ a multi-level strategy: faults are identified through a "two-out-of-three" voting mechanism (setting up three redundancies for key sensors), and the fault diagnosis accuracy formula is:

[0160] ;

[0161] In the formula, N correct N is the number of correct diagnoses. total For the total number of diagnostics, A≥99.5% in actual operation; when injector jamming is detected, ECU5 immediately activates the backup injector, which is redundantly designed, and distributes the fuel quantity corresponding to the faulty injector to other injectors to ensure a stable total supply; when critical components, such as the ammonia decomposition reactor 31, fail, the system automatically switches to "pure biodiesel mode", shuts off the liquid ammonia supply, maintains basic engine operation by adjusting the injection strategy, reduces the power to 70% of the rated value, and issues a maintenance prompt.

[0162] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A supply system for ammonia-to-hydrogen coupled with biodiesel, characterized in that, The supply system includes: A biodiesel tank (11) is connected to a biodiesel injector (13) which injects biodiesel into the engine cylinder (14). A liquid ammonia storage tank (21) is connected to a liquid ammonia injector (23) and is equipped with an emergency shut-off valve (24). When the ammonia content is detected to exceed the specified standard or the pressure monitoring device detects an abnormal pressure, the emergency shut-off valve (24) stops the supply of liquid ammonia. The ammonia decomposition reactor (31) is connected to the liquid ammonia injector (23). The interior is equipped with honeycomb ceramic as a support structure. The support structure is attached with catalytic substances, which can decompose ammonia into hydrogen and nitrogen. A mixer (4) with a venturi structure is connected to an ammonia decomposition reactor (31) and can premix a mixture of hydrogen and nitrogen gas with air before sending it into the engine cylinder (14) through a pipeline.

2. The ammonia-to-hydrogen coupled biodiesel supply system as described in claim 1, characterized in that: The biodiesel tank (11) is connected to the biodiesel injector (13) via the biodiesel pump (12) and the high-pressure common rail (16); Among them, the biodiesel injector (13) uses a nozzle with a small aperture. The timing and pressure of its injection are controlled by the ECU (5). When the liquid level is lower than the preset lower limit threshold L1, a replenishment command is triggered. Biodiesel injection quantity Q BD With engine power P engine The relationship is: ； In the formula, η BD For biodiesel combustion efficiency, H BD The low calorific value of biodiesel, where α is the hydrogen substitution coefficient. To measure real-time hydrogen production, To achieve maximum hydrogen production, the biodiesel injection rate will be dynamically adjusted based on the results as hydrogen production increases.

3. The ammonia-to-hydrogen coupled biodiesel supply system as described in claim 1, characterized in that: The liquid ammonia storage tank (21) is connected to the liquid ammonia injector (23) via the liquid ammonia pump (22), and the liquid ammonia injector (23) is installed at the inlet of the ammonia decomposition reactor (31); Among them, the output pressure of the liquid ammonia pump (22) is within the preset pressure range, and the liquid ammonia supply is... With biodiesel injection quantity Q BD The proportional relationship is: ； In the formula, Let β be the heat of combustion of ammonia, and β be the energy distribution coefficient. It is dynamically adjusted according to the engine load so that β∈[β1,β2], where β1 is taken for low load and β2 is taken for high load. The output pressure of the liquid ammonia pump (22) in the liquid ammonia supply section With reactor inlet pressure P reactor The relationship is: ； In the formula, ΔP pump ρ is the pump head, g is the density of liquid ammonia, h is the gravitational acceleration, and h is the conveying height.

4. The ammonia-to-hydrogen coupled biodiesel supply system as described in claim 1, characterized in that: The outer layer of the ammonia decomposition reactor (31) is equipped with finned pipes for recovering the residual heat from the exhaust gas discharged from the biodiesel supply section; the inner layer is equipped with electric heating elements for heating when the system is started. Among them, the hydrogen production from the ammonia decomposition reaction The relationship between the reaction temperature T and the catalytic activity A is as follows: ； In the formula, k0 is the reaction rate constant, E is the activation energy of the reaction, and R is the gas constant. This refers to the ammonia concentration. In the ammonia-to-hydrogen conversion process, the catalyst loading is gradient-distributed along the reactor axis, with the inlet loading A... in With output load A out The relationship is: A in =A out ×(1+δ); In the formula, δ is the gradient coefficient; this gradient distribution affects the ammonia decomposition efficiency. satisfy: ； In the formula, η0 is the baseline efficiency, T is the reaction temperature, and T0 is the reaction temperature. ref The reference temperature is used; the heat balance equation for the reactor is: Q electrical +Q waste =Q reaction +Q loss ; In the formula, Q electrical The heat provided by the electric heating element, Q waste To recover waste heat from exhaust gas, Q reaction Q is the heat required for the ammonia decomposition reaction. loss This is due to heat loss.

5. The ammonia-to-hydrogen coupled biodiesel supply system as described in claim 1, characterized in that: The supply system also includes: The safety auxiliary module includes an explosion-proof unit, a fire extinguishing unit, and an emergency ventilation unit. The explosion-proof unit is installed in the area where the ammonia decomposition reactor (31) and the liquid ammonia storage tank (21) are located. When a fire is detected, the explosion-proof unit and the fire extinguishing unit are activated to protect and extinguish the ammonia decomposition reactor (31) and the liquid ammonia storage tank (21). The emergency ventilation unit is activated in conjunction with the ammonia content when it exceeds the standard to accelerate the emission of harmful gases. The environmental adaptation module includes an ambient temperature sensor and an altitude sensor. The electronic control device adjusts the preheating time and heating power according to the ambient temperature and corrects the ratio of the mixed gas to air according to the altitude.

6. The ammonia-to-hydrogen coupled biodiesel supply system as described in claim 1, characterized in that: The explosion-proof unit includes a pressure relief valve and a flame detector. When an explosion risk or flame is detected, the pressure relief valve quickly releases pressure and simultaneously closes the emergency shut-off valve (24). The fire extinguishing unit uses extinguishing media suitable for extinguishing liquid fuel and gas fires, and is linked to the system power supply, automatically cutting off unnecessary power during fire extinguishing. The ventilation volume of the emergency ventilation unit can be automatically adjusted according to the ammonia concentration.

7. The ammonia-to-hydrogen coupled biodiesel supply system as described in claim 1, characterized in that: The dynamic balance coefficient K between the ammonia-hydrogen conversion efficiency and the biodiesel combustion efficiency is autonomously optimized based on the engine's real-time operating conditions. The formula for calculating K is as follows: ； In the formula, For ammonia decomposition efficiency, For hydrogen production power, For biodiesel combustion efficiency, Biodiesel consumption rate; Air-fuel ratio λ: ； In the formula, Q air For airflow, For hydrogen flow rate, γ air This is the oxygen content coefficient in the air. γ is the oxygen demand coefficient for hydrogen combustion. BD The oxygen demand coefficient for biodiesel combustion; ECU (5) adjusts the air flow rate Q air Keep λ within the optimal combustion range; Total energy output E total : ； In the formula, The calorific value of hydrogen is used to control the total energy output to match the engine power requirements.

8. A method for operating a supply system for ammonia-to-hydrogen coupled biodiesel as described in any one of claims 1 to 7, characterized in that, The method includes the following steps: ECU (5) performs a full system self-check, detecting the status parameters of each component, including status, liquid level, pressure, and concentration. After the self-check passes, it starts the biodiesel pump (12) and injects pure biodiesel to perform a cold start of the system. At the same time, the electric heating device (32) raises the temperature of the ammonia decomposition reactor (31) to the preset reaction start temperature and starts the liquid ammonia injector (23). In the initial state, the injection amount of liquid ammonia is the preset initial ratio of the biodiesel mass. ECU (5) synchronously establishes a load prediction model and pre-simulates the optimal temperature rise curve based on the ambient temperature and engine cylinder temperature within the preset time period before startup. If the self-check finds an abnormality, it will activate the fault warning. When the system is under low load, the proportion of liquid ammonia is in the first ratio range, and the mixture of hydrogen and nitrogen is injected through the intake pipe to form a stratified combustion state with biodiesel. The temperature of the reactor is maintained in the first temperature range. At this time, the ammonia decomposition rate is adjusted to above the first efficiency threshold, while the waste heat recovery ratio is controlled at the low load adaptation value. When the system is under medium load, the proportion of liquid ammonia is in the second ratio range. It switches to direct injection and pre-mixed combustion in the combustion cylinder, and the reactor temperature is maintained in the second temperature range. The dual-cycle thermal management mode is activated, and the cylinder waste heat and exhaust waste heat are distributed to the ammonia decomposition device and biodiesel preheating stage according to the preset ratio. When the system is under high load, the proportion of liquid ammonia is in the third ratio range. The heating power of the reactor is increased to ensure that the decomposition ratio of ammonia exceeds the second efficiency threshold. A preset pre-injection ratio of biodiesel is injected within a preset crankshaft angle range before the top dead center of the compression stroke. At the same time, the over-temperature protection mechanism is activated. When the reactor temperature exceeds the preset high temperature threshold, the liquid ammonia supply is reduced and the biodiesel injection ratio is increased. When shutting down, the liquid ammonia injection rate is gradually reduced until it stops, while biodiesel is continued to be delivered for the preset shutdown duration. The residual heat from the exhaust gas is used to decompose the residual ammonia. During this period, the residual concentration is monitored in real time using an ammonia content detection device, and the injectors and pipelines are purged. The operation data is saved and the status is recorded.

9. The method for operating a supply system for ammonia-to-hydrogen coupled biodiesel according to claim 8, characterized in that, It also includes the following steps: The high-temperature mixed gas generated during the conversion of ammonia into hydrogen is first preheated to the biodiesel by the first waste heat recovery device, raising its temperature to the preset preheating range. The cooled mixed gas enters the engine to participate in combustion. The exhaust gas after combustion flows through the second waste heat recovery device to drive the micro power generation device to generate electricity. The generated electricity is preferentially supplied to the electronic control device, induction device and heating element in the system, and the remaining electricity is stored in the backup energy storage device. The residual heat from the waste gas after power generation is used to assist in heating the reactor through a third waste heat recovery device. The heat distribution ratio can be intelligently adjusted according to real-time energy consumption needs, and each waste heat recovery device is equipped with a heat regulation valve.

10. The method for operating a supply system for ammonia-to-hydrogen coupled biodiesel according to claim 8, characterized in that, It also includes the following steps: Continuously compare the real-time data of each sensor with the standard parameter range, and initiate parameter self-calibration when a slight deviation occurs; When a component failure is detected, the corresponding fault tolerance strategy is activated according to the failure level.

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