Range-extended Hybrid Hydrogen-based Engine System and Its Control Method

Abstract

The present invention belongs to the technical field of automotive power systems, and in particular relates to an extended-range hybrid hydrogen-based engine system and its control method, including an in-cylinder direct injection hydrogen engine, a power generation system, an ammonia fuel supply system, a hydrogen supply system, and a post-treatment system; the ammonia fuel supply system includes a cooling water heater, a liquid ammonia tank, a liquid ammonia vaporizer, and an ammonia buffer tank, and the cooling water heater is used to heat the cooling water output by the hydrogen engine; the post-treatment system includes a post-treatment heater and an SCR system; the hydrogen supply system includes a cracker heater, an ammonia cracker, and a hydrogen buffer tank arranged in sequence. By using the cooling water heater to heat the cooling water output by the hydrogen engine, the cooling water can reach the lowest temperature required for vaporizing liquid ammonia in the liquid ammonia vaporizer, ensuring the vaporization effect of liquid ammonia, and solving the problem that the cooling water temperature is too low to meet the vaporization of liquid ammonia during the cold start of the hydrogen engine; ensuring the stability of the hydrogen production flow rate cracked by the cracker.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive power systems, and in particular relates to an extended-range hybrid hydrogen-based engine system and its control method. Background Art

[0002] Global climate and environmental changes have posed severe challenges to the economic and social development of humanity. Low-carbon or even zero-carbon has become an inevitable trend in the world's economic development, and low-carbon technologies will become the new "engine" of global economic development. The essence of internal combustion engine zero-carbon technology is to achieve zero carbon emissions throughout the life cycle by burning carbon-neutral fuels. Ammonia only produces nitrogen and water when completely burned, and there is no carbon emission either, making it a very promising green energy source.

[0003] Compared with other fuels, ammonia as an engine fuel has the characteristics of slow combustion speed, low combustion temperature, and high minimum ignition energy. This makes ammonia as an engine fuel require an extremely high compression ratio and an ignition fuel at the same time. Common ignition fuels include acetylene, dimethyl ether, gasoline, diesel, and hydrogen. Among these, only hydrogen is a carbon-free fuel, which has the characteristics of low ignition energy, wide combustion limits, and high combustion temperature. Ammonia, as a natural carrier of hydrogen, can thus supply hydrogen by cracking ammonia fuel to produce hydrogen. Of course, ammonia will cause emissions of NOx and NH3 when incompletely burned. However, the cost of hydrogen storage and transportation is expensive, and it is usually stored in the form of liquid ammonia. Since the boiling point temperature of liquid ammonia is -33°C under atmospheric pressure and the gaseous ammonia can be liquefied into liquid ammonia by pressurizing to 10 bar at room temperature (about 25°C). Therefore, the gas-liquid phase conversion of ammonia is greatly affected by environmental temperature and pressure. This will directly affect the stability of the hydrogen production flow rate of the ammonia cracking hydrogen generator and the ammonia injection amount sprayed into the post-treatment system or device (SCR), and ultimately affect the efficiency of the SCR in treating NOx emissions from the exhaust gas. Summary of the Invention

[0004] The purpose of the present invention is to address the above problems and provide an extended-range hybrid hydrogen-based engine system and its control method.

[0005] To achieve the above object, in the first aspect, the present invention provides the following technical solution: An extended-range hybrid hydrogen-based engine system, comprising: an in-cylinder direct injection hydrogen engine, a power generation system, an ammonia fuel supply system, a hydrogen supply system, and a post-treatment system; the power generation system includes a generator and a power battery electrically connected; the hydrogen engine is connected to the generator, the power battery supplies power to the ammonia fuel supply system, the hydrogen supply system, and the post-treatment system, and a battery power sensor is provided on the power battery;

[0006] The ammonia fuel supply system includes a cooling water heater, and a liquid ammonia tank, a liquid ammonia vaporizer, and an ammonia buffer tank that are connected in sequence. The cooling water heater is used to heat the cooling water output by the hydrogen engine to a first target temperature and then input it into the liquid ammonia vaporizer;

[0007] The after-treatment system includes an after-treatment heater and an SCR system. The after-treatment heater is used to heat the SCR system to a second target temperature, and the SCR system processes the pollutant emissions of the hydrogen engine based on the ammonia injected from the ammonia buffer tank;

[0008] The hydrogen supply system includes a cracker heater, an ammonia cracker, and a hydrogen buffer tank arranged in sequence; the cracker heater is used to heat the gas output from the exhaust pipe of the hydrogen engine to a third target temperature and then input it into the ammonia cracker. The ammonia cracker receives the ammonia input from the ammonia buffer tank, cracks out hydrogen, and then outputs it to the hydrogen buffer tank, and the hydrogen buffer tank is connected to the hydrogen engine.

[0009] Further, the hydrogen supply system further includes a hydrogen booster pump; the hydrogen booster pump is connected between the ammonia cracker and the hydrogen buffer tank.

[0010] Further, the ammonia fuel supply system includes a cooling water pipeline that connects the hydrogen engine, the cooling water heater, and the liquid ammonia vaporizer; a cooling water temperature sensor and a cooling water switch valve are arranged on the cooling water pipeline.

[0011] Further, the ammonia fuel supply system further includes a first ammonia supply pipe and a second ammonia supply pipe, one ends of which are respectively connected to the ammonia buffer tank; the other end of the first ammonia supply pipe is connected to the ammonia cracker, and an ammonia cracking switch valve is arranged on the first ammonia supply pipe; the other end of the second ammonia supply pipe is provided with a post-treatment ammonia nozzle, and the post-treatment ammonia nozzle is connected to the SCR system.

[0012] Further, the after-treatment system further includes an after-treatment temperature sensor, and the after-treatment temperature sensor is arranged in the SCR system.

[0013] Further, the hydrogen supply system further includes an exhaust pipe temperature sensor, and the exhaust pipe temperature sensor is arranged on the exhaust pipe of the hydrogen engine.

[0014] Further, the hydrogen supply system further includes a hydrogen pressure sensor and a hydrogen mass sensor, and the hydrogen pressure sensor and the hydrogen mass sensor are arranged on the hydrogen buffer tank.

[0015] Compared with the prior art, the range-extended hybrid hydrogen-based engine system provided by the present invention has the following beneficial effects: By using the cooling water heater to heat the cooling water output by the hydrogen engine, the cooling water can reach the lowest temperature required for vaporizing liquid ammonia in the liquid ammonia vaporizer, ensuring the vaporization effect of liquid ammonia and solving the problem that the cooling water temperature is too low to meet the requirement of liquid ammonia vaporization during cold start of the hydrogen engine; By using the cracker heater to heat the exhaust pipe of the hydrogen engine and the after-treatment heater to heat the SCR system, the stability of the hydrogen production flow cracked by the cracker is ensured, and the ammonia injection amount of the SCR system is also ensured, improving the efficiency of the SCR system in treating NOx in the tail gas emissions.

[0016] In a second aspect, the present invention provides the following technical solution: A control method for the above range-extended hybrid hydrogen-based engine system, comprising the following steps:

[0017] Step S1: Use the battery power sensor to obtain the remaining available power of the power battery; when the remaining available power is lower than a preset first threshold, proceed to step S2;

[0018] Step S2: Obtain the hydrogen mass in the hydrogen buffer tank; when the hydrogen mass is lower than a preset second threshold, determine whether the operating temperature of the SCR system reaches the second target temperature. If not, use the after-treatment heater to heat the SCR system to the second target temperature; when the operating temperature of the SCR system reaches the second target temperature, use the SCR system to treat the pollutant emissions of the hydrogen engine, and the hydrogen engine ignites and operates;

[0019] Step S3: Obtain the temperature of the exhaust pipe of the hydrogen engine; when the temperature of the exhaust pipe does not reach the third target temperature, use the cracker heater to heat the exhaust pipe; when the temperature of the exhaust pipe reaches the third target temperature, use the ammonia cracker to crack the ammonia input from the ammonia buffer tank, and output the cracked hydrogen to the hydrogen buffer tank; use the hydrogen buffer tank to supply hydrogen to the hydrogen engine;

[0020] Step S4: Obtain the temperature of the cooling water output by the hydrogen engine; when the temperature of the cooling water does not reach the first target temperature, use the cooling water heater to heat the cooling water output by the hydrogen engine to the first target temperature and then input it into the liquid ammonia vaporizer.

[0021] In a further implementation manner of the above control method, in step S2, when the hydrogen mass is higher than or equal to the second threshold, return to step S1.

[0022] In a further implementation manner of the above control method, before the hydrogen gas cracked by the ammonia cracker is output to the hydrogen buffer tank in step S3, it further includes a step of boosting the hydrogen gas cracked by the ammonia cracker by using a hydrogen booster pump connected between the ammonia cracker and the hydrogen buffer tank.

[0023] Compared with the prior art, the control method of the range-extended hybrid hydrogen-based engine system provided by the present invention has the following beneficial effects:

[0024] By obtaining the temperature of the cooling water output by the hydrogen engine; when the temperature of the cooling water does not reach the first target temperature, the cooling water output by the hydrogen engine is heated to the first target temperature by using a cooling water heater and then input into the liquid ammonia vaporizer to ensure the liquid ammonia gasification effect, solving the problem that the liquid ammonia cannot be gasified due to the low temperature of the cooling water during the cold start of the hydrogen engine; by obtaining the temperature of the exhaust pipe of the hydrogen engine; when the temperature of the exhaust pipe does not reach the third target temperature, the exhaust pipe is heated by using a cracker heater; by obtaining the operating temperature of the SCR system, when its operating temperature does not reach the second target temperature, the SCR system is heated by using a post-treatment heater; ensuring the stability of the hydrogen production flow rate cracked by the cracker and also ensuring the ammonia injection amount of the SCR system, improving the efficiency of the SCR system in treating tail gas emissions of NOx. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of a range-extended hybrid hydrogen-based engine system proposed by the present invention;

[0026] Figure 2 It is a schematic control logic diagram of step S1 of the control method of the present invention.

[0027] Figure 3 It is a schematic control logic diagram of step S2 of the control method of the present invention.

[0028] Figure 4 It is a schematic control logic diagram of step S3 of the control method of the present invention.

[0029] Figure 5 It is a schematic control logic diagram of step S4 of the control method of the present invention.

[0030] In the figure: 1 - hydrogen engine; 2 - hydrogen gas rail; 3 - hydrogen in-cylinder direct injection injector; 5 - hydrogen gas rail pressure sensor; 6 - generator; 7 - power battery; 8 - motor; 9 - drive system; 10 - liquid ammonia tank; 11 - ammonia buffer tank; 12 - post-treatment ammonia switching valve; 13 - liquid ammonia vaporizer; 14 - cooling water heater; 15 - cooling water switching valve; 16 - cooling water temperature sensor; 18 - post-treatment system; 19 - post-treatment heater; 20 - ammonia cracking switching valve; 21 - hydrogen booster pump; 22 - hydrogen circuit switching valve; 23 - hydrogen buffer tank; 24 - hydrogen switching valve; 25 - hydrogen pressure regulating valve; 26 - exhaust pipe temperature sensor; 27 - exhaust pipe; 28 - ammonia cracker; 29 - post-treatment ammonia nozzle; 30 - cracker heater; 31 - battery charge sensor; 32 - hydrogen mass sensor; 33 - ammonia tank switching valve. Specific embodiments

[0031] The following embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0032] The essence of internal combustion engine zero-carbon technology is to achieve zero carbon emissions throughout the life cycle by burning carbon-neutral fuels. Ammonia only produces nitrogen and water when completely burned, and there is no carbon emission either, making it a promising green energy source. As an engine fuel, ammonia has the characteristics of slow combustion speed, low combustion temperature, and high minimum ignition energy, which means that ammonia as an engine fuel requires an extremely high compression ratio and an ignition fuel at the same time; common ignition fuels include acetylene, dimethyl ether, gasoline, diesel, and hydrogen, and only hydrogen among them is a carbon-free fuel, which has the characteristics of low ignition energy, wide combustion limit, and high combustion temperature. Ammonia, as a natural carrier of hydrogen, can thus supply hydrogen by cracking ammonia fuel to produce hydrogen. Of course, ammonia will cause emissions of NOx and NH3 when incompletely burned. However, the cost of hydrogen storage and transportation is expensive, and it is usually stored in the form of liquid ammonia. Since the boiling point temperature of liquid ammonia is -33°C under atmospheric pressure and the gaseous ammonia can be liquefied into liquid ammonia by pressurizing to 10 bar at normal temperature (about 25°C). Therefore, the gas-liquid phase conversion of ammonia is greatly affected by environmental temperature and pressure. This will directly affect the hydrogen output flow stability of the ammonia cracking hydrogen generator and the ammonia injection amount sprayed into the post-treatment system or device (SCR), and ultimately affect the efficiency of the SCR in treating NOx emissions from the exhaust gas.

[0033] To solve the above problems, the present invention proposes an extended-range hybrid hydrogen-based engine system and its control method.

[0034] As Figure 1As shown in the figure, the range-extended hybrid hydrogen-based engine system proposed by the present invention includes: an in-cylinder direct injection hydrogen engine 1, a power generation system, an ammonia fuel supply system, a hydrogen supply system, and a post-treatment system 18; the power generation system includes a generator 6 and a power battery 7 that are electrically connected; the hydrogen engine 1 is connected to the generator 6, the power battery 7 supplies power to the ammonia fuel supply system, the hydrogen supply system, and the post-treatment system 18, and a battery power sensor 31 is provided on the power battery 7; the battery power sensor 31 can obtain the remaining available power of the power battery 7, and according to the parameters of the power battery 7 and the vehicle, the driving time of the vehicle equipped with the power battery 7 can be obtained. The power battery 7 is electrically connected to a motor for supplying power to the motor, and the motor is connected to a transmission system 9. A hydrogen gas rail 2, a hydrogen in-cylinder direct injection injector 3, and a hydrogen rail pressure sensor 5 are provided in the hydrogen engine 1.

[0035] The ammonia fuel supply system includes a cooling water heater 14 and a liquid ammonia tank 10, a liquid ammonia vaporizer 13, and an ammonia buffer tank 11 that are connected in sequence. The cooling water heater 14 is used to heat the cooling water output by the hydrogen engine 1 to a first target temperature and then input it into the liquid ammonia vaporizer 13; an ammonia tank switch valve 33 is provided between the liquid ammonia tank 10 and the liquid ammonia vaporizer 13.

[0036] The post-treatment system 18 includes a post-treatment heater 19 and an SCR system. The post-treatment heater 19 is used to heat the SCR system to a second target temperature, and the SCR system treats the pollutant emissions of the hydrogen engine 1 based on the ammonia injected from the ammonia buffer tank 11;

[0037] The hydrogen supply system includes a cracker heater 30, an ammonia cracker 28, and a hydrogen buffer tank 23 that are arranged in sequence; the cracker heater 30 is used to heat the gas output from the exhaust pipe 27 of the hydrogen engine 1 to a third target temperature and then input it into the ammonia cracker 28. The ammonia cracker 28 receives the ammonia input from the ammonia buffer tank 11, cracks out hydrogen, and then outputs it to the hydrogen buffer tank 23. The hydrogen buffer tank 23 is connected to the hydrogen engine 1.

[0038] The hydrogen supply system further includes a hydrogen booster pump 21; the hydrogen booster pump 21 is connected between the ammonia cracker 28 and the hydrogen buffer tank 23. A hydrogen circuit switch valve 22 is provided between the hydrogen booster pump 21 and the hydrogen buffer tank 23. A hydrogen switch valve 24 is provided at the outlet end of the hydrogen buffer tank 23, and a hydrogen pressure regulating valve 25 is provided between the hydrogen switch valve 24 and the hydrogen engine 1.

[0039] The hydrogen engine 1 of this embodiment is a direct injection type in the cylinder, which requires a relatively high hydrogen injection pressure (20 bar - 40 bar). In order to achieve stable and relatively high pressure of hydrogen, a hydrogen booster pump 21 is equipped between the ammonia cracker 28 and the hydrogen buffer tank 23 in this embodiment to boost the low-pressure hydrogen (such as 5 - 8 bar) to 25 bar and store the boosted hydrogen in the hydrogen buffer tank 23.

[0040] The ammonia fuel supply system includes a cooling water pipeline, and the cooling water pipeline communicates with the hydrogen engine 1, the cooling water heater 14, and the liquid ammonia vaporizer 13; a cooling water temperature sensor 16 and a cooling water switch valve 15 are arranged on the cooling water pipeline. The cooling water temperature sensor 16 is arranged at the cooling water outlet of the hydrogen engine 1. In some embodiments, the cooling water pipeline includes a first pipeline and a second pipeline, the first pipeline and the second pipeline are in parallel, wherein the first pipeline directly communicates with the liquid ammonia vaporizer 13 and the hydrogen engine 1, and the second pipeline communicates with the liquid ammonia vaporizer 13, the cooling water heater 14, and the hydrogen engine 1; a cooling water switch valve 15 is arranged on each of the first pipeline and the second pipeline, or a cooling water switch valve 15 is only arranged on the second pipeline.

[0041] The ammonia fuel supply system further includes a first ammonia supply pipe and a second ammonia supply pipe, one ends of which are respectively communicated with the ammonia buffer tank 11; the other end of the first ammonia supply pipe is communicated with the ammonia cracker 28, and an ammonia cracking switch valve 20 is arranged on the first ammonia supply pipe; the other end of the second ammonia supply pipe is provided with a post-treatment ammonia nozzle 29, the post-treatment ammonia nozzle 29 communicates with the SCR system, and a post-treatment ammonia switch valve 12 is arranged on the second ammonia supply pipe.

[0042] The post-treatment system 18 further includes a post-treatment temperature sensor, and the post-treatment temperature sensor is arranged in the SCR system. The post-treatment temperature sensor is used to monitor the working temperature of the SCR system in real time and can also be used to monitor the heating temperature of the post-treatment heater 19.

[0043] The hydrogen supply system further includes an exhaust pipe temperature sensor 26, and the exhaust pipe temperature sensor 26 is arranged on the exhaust pipe 27 of the hydrogen engine 1. The exhaust pipe temperature sensor 26 is used to monitor the temperature of the exhaust pipe 27 and can also be used to monitor the temperature of the gas in the exhaust pipe 27.

[0044] The hydrogen supply system further includes a hydrogen pressure sensor and a hydrogen mass sensor 32, and the hydrogen pressure sensor and the hydrogen mass sensor 32 are arranged on the hydrogen buffer tank 23. The hydrogen pressure sensor monitors the pressure of the hydrogen in the hydrogen buffer tank 23 in real time, and the hydrogen mass sensor 32 monitors the mass of the hydrogen in the hydrogen buffer tank 23 in real time.

[0045] The ammonia in the ammonia buffer tank 11 and the hydrogen in the hydrogen buffer tank 23 are used as fuels required for the cold start of the hydrogen engine 1. It is necessary to ensure in real time that there is a certain amount of ammonia and hydrogen in the ammonia buffer tank 11 and the hydrogen buffer tank 23 to provide a fuel source for the next start of the hydrogen engine 1.

[0046] By using the cooling water heater 14 to heat the cooling water output by the hydrogen engine 1, the cooling water can reach the lowest temperature for vaporizing liquid ammonia in the liquid ammonia vaporizer 13, ensuring the vaporization effect of liquid ammonia and solving the problem that the cooling water temperature is too low to meet the vaporization of liquid ammonia during the cold start of the hydrogen engine 1; using the cracker heater 30 to heat the exhaust pipe 27 of the hydrogen engine 1 and using the post-treatment heater 19 to heat the SCR system, ensuring the stability of the hydrogen production flow cracked by the cracker and also ensuring the ammonia injection amount of the SCR system, and improving the efficiency of the SCR system in treating the tail gas emission NOx.

[0047] Based on the same inventive concept, the present invention proposes a control method for an extended-range hybrid hydrogen-based engine system. Among them, the extended-range hybrid hydrogen-based engine system includes an in-cylinder direct injection hydrogen engine 1, a power generation system, an ammonia fuel supply system, a hydrogen supply system, and a post-treatment system 18; the power generation system includes a generator 6 and a power battery 7 that are electrically connected; the hydrogen engine 1 is connected to the generator 6, the power battery 7 supplies power to the ammonia fuel supply system, the hydrogen supply system, and the post-treatment system 18, and a battery power sensor 31 is provided on the power battery 7; the ammonia fuel supply system includes a cooling water heater 14 and a liquid ammonia tank 10, a liquid ammonia vaporizer 13, and an ammonia buffer tank 11 that are connected in sequence, and the cooling water heater 14 is used to heat the cooling water output by the hydrogen engine 1 to a first target temperature and then input it into the liquid ammonia vaporizer 13; the post-treatment system 18 includes a post-treatment heater 19 and an SCR system, the post-treatment heater 19 is used to heat the SCR system to a second target temperature, and the SCR system treats the pollutant emissions of the hydrogen engine 1 based on the ammonia injected from the ammonia buffer tank 11; the hydrogen supply system includes a cracker heater 30, an ammonia cracker 28, and a hydrogen buffer tank 23 arranged in sequence; the cracker heater 30 is used to heat the gas output from the exhaust pipe 27 of the hydrogen engine 1 to a third target temperature and then input it into the ammonia cracker 28, the ammonia cracker 28 receives the ammonia input from the ammonia buffer tank 11, cracks out hydrogen and then outputs it to the hydrogen buffer tank 23, and the hydrogen buffer tank 23 is connected to the hydrogen engine 1.

[0048] The hydrogen supply system further includes a hydrogen booster pump 21; the hydrogen booster pump 21 is connected between the ammonia cracker 28 and the hydrogen buffer tank 23. The ammonia fuel supply system includes a cooling water pipeline, and the cooling water pipeline connects the hydrogen engine 1, the cooling water heater 14, and the liquid ammonia vaporizer 13; a cooling water temperature sensor 16 and a cooling water switch valve 15 are provided on the cooling water pipeline. The ammonia fuel supply system further includes a first ammonia supply pipe and a second ammonia supply pipe whose one ends are respectively connected to the ammonia buffer tank 11; the other end of the first ammonia supply pipe is connected to the ammonia cracker 28, and an ammonia cracking switch valve 20 is provided on the first ammonia supply pipe; the other end of the second ammonia supply pipe is provided with a post-treatment ammonia nozzle 29, and the post-treatment ammonia nozzle 29 is connected to the SCR system.

[0049] The post-treatment system 18 further includes a post-treatment temperature sensor, and the post-treatment temperature sensor is arranged in the SCR system. The hydrogen supply system further includes an exhaust pipe temperature sensor 26, and the exhaust pipe temperature sensor 26 is arranged on the exhaust pipe 27 of the hydrogen engine 1. The hydrogen supply system further includes a hydrogen pressure sensor and a hydrogen mass sensor 32, and the hydrogen pressure sensor and the hydrogen mass sensor 32 are arranged on the hydrogen buffer tank 23.

[0050] The control method of the above range-extended hybrid hydrogen-based engine system includes the following steps:

[0051] Step S1: Use the battery power sensor 31 to obtain the remaining available power of the power battery 7; when the remaining available power is lower than a preset first threshold, enter Step S2;

[0052] Step S2: Obtain the hydrogen mass in the hydrogen buffer tank 23; when the hydrogen mass is higher than or equal to the second threshold, return to Step S1; when the hydrogen mass is lower than a preset second threshold, determine whether the operating temperature of the SCR system reaches the second target temperature, if not, use the post-treatment heater 19 to heat the SCR system to the second target temperature; when the operating temperature of the SCR system reaches the second target temperature, use the SCR system to treat the pollutant emissions of the hydrogen engine 1, and the hydrogen engine 1 ignites and runs;

[0053] Step S3: Obtain the temperature of the exhaust pipe 27 of the hydrogen engine 1; when the temperature of the exhaust pipe 27 does not reach the third target temperature, heat the exhaust pipe 27 using the cracker heater 30; when the temperature of the exhaust pipe 27 reaches the third target temperature, crack the ammonia input from the ammonia buffer tank 11 using the ammonia cracker 28, and output the cracked hydrogen to the hydrogen buffer tank 23; use the hydrogen buffer tank 23 to supply hydrogen to the hydrogen engine 1; wherein, before outputting the cracked hydrogen to the hydrogen buffer tank 23 using the ammonia cracker 28, it further includes a step of pressurizing the hydrogen cracked by the ammonia cracker 28 using a hydrogen booster pump 21 connected between the ammonia cracker 28 and the hydrogen buffer tank 23.

[0054] Step S4: Obtain the temperature of the cooling water output by the hydrogen engine 1; when the temperature of the cooling water does not reach the first target temperature, heat the cooling water output by the hydrogen engine 1 to the first target temperature using the cooling water heater 14 and then input it into the liquid ammonia vaporizer 13.

[0055] The hydrogen engine 1 is only one power source and is not directly connected to the transmission system 9. When the power of the power battery 7 is low, the control logic for switching the working mode of the hydrogen engine 1: when the power of the power battery 7 is sufficient to drive the motor and the transmission system 9, the hydrogen engine 1 does not work. The power battery 7 serves as a power source to provide power for the motor. Only when the power of the power battery 7 is less than a certain period (such as: 30 min) required to supply the entire system, it will be judged whether to start the operation of the hydrogen engine 1. When judging whether to start the hydrogen engine 1, the hydrogen quantity in the hydrogen buffer tank 23 is monitored in real time, and its starting sequence and judgment basis are as Figure 2 shown in the control logic S1. The starting process and judgment basis of the hydrogen engine 1 are as Figure 3 shown in the control logic S2. The starting sequence and control logic S3 of the ammonia cracker 28 are as Figure 4 shown. The control logics S1, S2, and S3 have a sequential relationship, and the three are closely related. The control logic S2 can return to the control logic S1. The control logic S4 can operate independently.

[0056] Figure 2Description of the control logic or step S1: According to the power of the power battery 7 and the power consumption required by the vehicle working conditions, it is predicted in real time whether the power battery 7 can support the vehicle to travel for a certain period of time (for example: 30 minutes, i.e., the first threshold). (1): If it is predicted that the power battery 7 is not sufficient to support the vehicle to travel for a certain period of time (for example: 30 minutes), according to the hydrogen pressure and hydrogen mass in the hydrogen buffer tank 23 monitored in real time, enter the judgment logic S2 to judge whether to start the hydrogen engine 1 to work. (2): If it is predicted that the power battery 7 is sufficient to support the vehicle to travel for a certain period of time (for example: >30 minutes), then the power battery 7 drives the motor to drive the power transmission system to provide power for the vehicle, and the hydrogen engine 1 does not work. At the same time, the hydrogen pressure and hydrogen mass in the hydrogen buffer tank 23 are monitored in real time, and enter the judgment logic S2 to judge whether to start the hydrogen engine 1 to work.

[0057] Figure 3 Description of the control logic or step S2: Judge whether to start the hydrogen engine 1 according to the hydrogen mass sensor 32 in the hydrogen buffer tank 23. (1) If the hydrogen mass in the hydrogen buffer tank 23 can ensure that the hydrogen engine 1 runs smoothly for a certain period of time (for example, 30 minutes), then the hydrogen engine 1 does not work temporarily, the power of the vehicle is provided by the power battery 7, the ammonia cracker 28 is in the closed state, and then return to the control logic or step S1. (2) If the hydrogen mass in the hydrogen buffer tank 23 (for example, 2 kg, i.e., the second threshold) cannot ensure that the hydrogen engine 1 runs smoothly for a certain period of time (for example, 30 minutes), then enter the mode of starting the hydrogen engine 1. When the hydrogen engine 1 runs, pollutants such as NOx will be emitted. Therefore, before the hydrogen engine 1 ignites and runs, in order to ensure the effective treatment of NOx, it is necessary to ensure that the temperature of the NOx catalytic reduction device SCR system reaches the effective working temperature (for example, 300 °C, i.e., the second target temperature). If the SCR system does not reach the effective working temperature (for example, 300 °C), then use the after-treatment heater 19 electrically connected to the power battery 7 to heat the SCR system by electric heating. When the SCR system reaches the working temperature, open the hydrogen switch valve 24 provided at the outlet end of the hydrogen buffer tank 23, start the hydrogen engine 1, and inject ammonia into the SCR system at the same time, and use the SCR system to efficiently treat the pollutant emissions NOx of the hydrogen engine 1. Next, enter the control logic S3 to judge whether to start the ammonia cracker 28.

[0058] Figure 4 Description of the control logic or step S3: Judge whether to supply ammonia to the ammonia cracker 28 according to the temperature of the exhaust pipe 27. (1) If the temperature of the exhaust pipe 27 or the exhaust temperature is higher than a certain temperature (for example, 300 °C, i.e., the third target temperature), then open the ammonia cracking switch valve 20, supply ammonia to the ammonia cracker 28, and produce hydrogen. At the same time, open the hydrogen booster pump 21 to supply high-pressure hydrogen to the hydrogen buffer tank 23.

[0059] Figure 5 Description of the control logic or step S4: The heat source of the liquid ammonia vaporizer 13 is provided by the cooling water of the hydrogen engine 1. (1) When the temperature of the cooling water of the hydrogen engine 1 does not reach the first target temperature (80 - 90 °C) and the amount of ammonia in the ammonia buffer tank is low, the cooling water heater 14 will be started to heat the cooling water of the hydrogen engine 1 so that the water temperature quickly reaches the target value of the first target temperature (80 - 90 °C), enabling the normal operation of the liquid ammonia vaporizer 13. (2) When the temperature of the cooling water of the hydrogen engine 1 has reached the first target temperature and the amount of ammonia in the ammonia buffer tank is low, the cooling water enters the liquid ammonia vaporizer 13 to vaporize the liquid ammonia into ammonia, and the ammonia enters the ammonia buffer tank 11 for storage.

[0060] By obtaining the temperature of the cooling water output by the hydrogen engine 1; when the temperature of the cooling water does not reach the first target temperature, the cooling water output by the hydrogen engine 1 is heated to the first target temperature by the cooling water heater 14 and then input into the liquid ammonia vaporizer 13 to ensure the liquid ammonia vaporization effect, solving the problem that the liquid ammonia vaporization cannot be satisfied due to the low temperature of the cooling water during the cold start of the hydrogen engine 1; by obtaining the temperature of the exhaust pipe 27 of the hydrogen engine 1; when the temperature of the exhaust pipe 27 does not reach the third target temperature, the exhaust pipe 27 is heated by the cracker heater 30; by obtaining the operating temperature of the SCR system, when its operating temperature does not reach the second target temperature, the SCR system is heated by the aftertreatment heater 19; ensuring the stability of the hydrogen production flow rate cracked by the cracker and also ensuring the ammonia injection amount of the SCR system, improving the efficiency of the SCR system in treating tail gas emissions of NOx.

[0061] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control method for an extended-range hybrid hydrogen-based engine system, characterized in that, the extended-range hybrid hydrogen-based engine system includes: an in-cylinder direct-injection hydrogen engine, a power generation system, an ammonia fuel supply system, a hydrogen supply system, and a post-treatment system; the power generation system includes a generator and a power battery connected electrically; the hydrogen engine is connected to the generator, the power battery supplies power to the ammonia fuel supply system, the hydrogen supply system, and the post-treatment system, and a battery power sensor is provided on the power battery; the ammonia fuel supply system includes a cooling water heater and a liquid ammonia tank, a liquid ammonia vaporizer, and an ammonia buffer tank connected in sequence, and the cooling water heater is used to heat the cooling water output by the hydrogen engine to a first target temperature and then input it into the liquid ammonia vaporizer; the post-treatment system includes a post-treatment heater and an SCR system, the post-treatment heater is used to heat the SCR system to a second target temperature, and the SCR system treats the pollution emissions of the hydrogen engine based on the ammonia injected from the ammonia buffer tank; the hydrogen supply system includes a cracker heater, an ammonia cracker, and a hydrogen buffer tank arranged in sequence; the cracker heater is used to heat the gas output from the exhaust pipe of the hydrogen engine to a third target temperature and then input it into the ammonia cracker, the ammonia cracker receives the ammonia input from the ammonia buffer tank, cracks out hydrogen and then outputs it to the hydrogen buffer tank, and the hydrogen buffer tank is connected to the hydrogen engine; the control method for the extended-range hybrid hydrogen-based engine system includes the following steps: Step S1, use the battery power sensor to obtain the remaining available power of the power battery; when the remaining available power is lower than a preset first threshold, enter Step S2; Step S2, obtain the hydrogen mass in the hydrogen buffer tank; when the hydrogen mass is lower than a preset second threshold, judge whether the working temperature of the SCR system reaches the second target temperature, if not, use the post-treatment heater to heat the SCR system to the second target temperature; when the working temperature of the SCR system reaches the second target temperature, use the SCR system to treat the pollution emissions of the hydrogen engine, and the hydrogen engine ignites and runs; Step S3, obtain the temperature of the exhaust pipe of the hydrogen engine; when the temperature of the exhaust pipe does not reach the third target temperature, use the cracker heater to heat the exhaust pipe; when the temperature of the exhaust pipe reaches the third target temperature, use the ammonia cracker to crack the ammonia input from the ammonia buffer tank, output the cracked hydrogen to the hydrogen buffer tank; use the hydrogen buffer tank to supply hydrogen to the hydrogen engine; Step S4, obtain the temperature of the cooling water output by the hydrogen engine; when the temperature of the cooling water does not reach the first target temperature, use the cooling water heater to heat the cooling water output by the hydrogen engine to the first target temperature and then input it into the liquid ammonia vaporizer.

2. The control method for the extended-range hybrid hydrogen-based engine system according to claim 1, characterized in that, The hydrogen supply system further includes a hydrogen booster pump; the hydrogen booster pump is connected between the ammonia cracker and the hydrogen buffer tank.

3. The control method of the range-extended hybrid hydrogen-based engine system according to claim 1, characterized in that the ammonia fuel supply system includes a cooling water pipeline, and the cooling water pipeline is connected to the hydrogen engine, the cooling water heater and the liquid ammonia vaporizer; a cooling water temperature sensor and a cooling water switch valve are arranged on the cooling water pipeline.

4. The control method of the range-extended hybrid hydrogen-based engine system according to claim 1, characterized in that the ammonia fuel supply system further includes a first ammonia supply pipe and a second ammonia supply pipe, one ends of which are respectively connected to the ammonia buffer tank; the other end of the first ammonia supply pipe is connected to the ammonia cracker, and an ammonia cracking switch valve is arranged on the first ammonia supply pipe; the other end of the second ammonia supply pipe is provided with a post-treatment ammonia nozzle, and the post-treatment ammonia nozzle is connected to the SCR system.

5. The control method of the range-extended hybrid hydrogen-based engine system according to claim 1, characterized in that the post-treatment system further includes a post-treatment temperature sensor, and the post-treatment temperature sensor is arranged in the SCR system.

6. The control method of the range-extended hybrid hydrogen-based engine system according to claim 1, characterized in that the hydrogen supply system further includes an exhaust pipe temperature sensor, and the exhaust pipe temperature sensor is arranged on the exhaust pipe of the hydrogen engine.

7. The control method of the range-extended hybrid hydrogen-based engine system according to any one of claims 1 to 6, characterized in that the hydrogen supply system further includes a hydrogen pressure sensor and a hydrogen mass sensor, and the hydrogen pressure sensor and the hydrogen mass sensor are arranged on the hydrogen buffer tank.

8. The control method of the range-extended hybrid hydrogen-based engine system according to claim 1, characterized in that in step S2, when the hydrogen mass is higher than or equal to the second threshold, return to step S1.

9. The control method of the range-extended hybrid hydrogen-based engine system according to claim 1, characterized in that in step S3, before the hydrogen cracked by the ammonia cracker is output to the hydrogen buffer tank, it further includes a step of boosting the hydrogen cracked by the ammonia cracker by using a hydrogen booster pump connected between the ammonia cracker and the hydrogen buffer tank.

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