Hydrogen internal combustion engine injection control method based on pre-combustion chamber ignition and engine system

Abstract

The invention discloses a hydrogen internal combustion engine injection control method based on pre-combustion chamber ignition, which comprises the following steps of: when a piston is positioned in a range of a crankshaft angle of 50-70 degrees before a compression top dead center, starting to inject hydrogen into a pre-combustion chamber; the hydrogen injection duration of the pre-combustion chamber is controlled to be smaller than a 5-degree crankshaft angle, and the equivalence ratio of the pre-combustion chamber during ignition is 0.8-1.2; when the piston is close to an upper dead center, a pre-combustion chamber spark plug is triggered to ignite, so that a pre-combustion chamber flame kernel is formed within a crankshaft angle of 1-5 degrees after ignition; flame of the pre-combustion chamber is sprayed into the main combustion chamber through the jet flow channel, multi-point ignition flame cores are formed in the main combustion chamber, and combustion of mixed gas formed by mixing hydrogen and air is promoted. And when the compression stroke is finished, hydrogen injection of the pre-combustion chamber is stopped, and the total injection duration angle does not exceed the 100-degree crankshaft angle before the lower dead center of the piston. According to the hydrogen internal combustion engine injection control method based on pre-combustion chamber ignition, by optimizing the time, duration and control strategy of pre-combustion chamber fuel injection and cooperating with a corresponding sensing and feedback adjusting mechanism, stable and rapid ignition and flame propagation of hydrogen lean combustion are achieved, and the combustion efficiency is improved. The lean burn limit is widened, NOx emission is reduced, and the heat efficiency of the engine is remarkably improved. The invention further discloses an engine system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogen fuel internal combustion engines, and in particular, the present application relates to a hydrogen internal combustion engine injection control method based on pre-chamber ignition and an engine system. BACKGROUND

[0002] Under the global trend of energy saving and emission reduction, hydrogen is considered as one of the clean alternative fuels due to its high calorific value, renewable production potential and zero carbon emission. Hydrogen has the characteristics of fast burning speed and wide flammable equivalence ratio range, which has attracted widespread attention in the field of internal combustion engines. However, hydrogen internal combustion engines face many challenges in practical application, such as unstable combustion under high equivalence ratio conditions, increased tendency of knock and limited power density. Hydrogen is extremely easy to self-ignite at high temperature and the flame propagates rapidly, which requires very low ignition energy, resulting in problems such as abnormal combustion (such as knock, pre-ignition) and backfire. At the same time, hydrogen combustion still produces NOx pollution during chemical reaction, which needs to be effectively controlled.

[0003] In order to reduce NOx emissions, the industry often adopts the strategy of ultra-lean combustion, that is, running the hydrogen engine with an air excess coefficient much higher than λ=2, so that the NOx emission level can be almost negligible. Studies have shown that the TJI technology of hydrogen can extend the lean combustion limit to an equivalence ratio of about λ=4.5. Under such extremely lean combustion conditions, NOx emissions are greatly reduced, and even without aftertreatment, it can meet the stringent standards. However, the excessively lean mixture will reduce the combustion rate and engine power density, resulting in poor combustion stability. Another traditional measure is to use exhaust gas recirculation (EGR) to dilute, but the condensation of water after cooling and the low enthalpy limit the amount of EGR, and the EGR system needs additional exhaust pumping work, which reduces the engine efficiency. There is also a solution to dilute hydrogen by injecting liquid water into the intake air to reduce the combustion temperature and the temperature of the piston and other components, thereby suppressing knock and reducing NOx. For example, the prior art proposes a sequential control method of injecting water first and then hydrogen in the intake stroke to alleviate the problems of backfire, self-ignition and knock in hydrogen combustion. The above solutions solve the abnormal problems of hydrogen combustion to some extent, but also have the disadvantages of increasing cost and complexity due to the introduction of new systems (such as EGR, water injection), or the decline of engine performance.

[0004] To address the poor stability of hydrogen lean burn combustion and the high tendency of abnormal combustion, pre-chamber ignition (also known as turbulent jet ignition, TJI for short) technology has emerged in the prior art. This technology sets up a small pre-chamber outside the main combustion chamber, uses the relatively rich mixture in the pre-chamber to ignite and burn, and generates a high-speed flame jet that is injected into the main combustion chamber to achieve multi-point ignition of the lean mixture in the main combustion chamber. TJI can significantly accelerate flame propagation and shorten combustion duration, thereby improving engine thermal efficiency and expanding the equivalence ratio range of hydrogen lean stable combustion. Existing research has shown that, compared with traditional spark ignition, pre-chamber ignition achieves higher combustion efficiency at a lower equivalence ratio. TJI technology has been successfully applied to engines using fuels such as gasoline and natural gas, and has shown great potential for improving lean burn combustion and reducing emissions in hydrogen and ammonia fuel engines. For example, high-speed photography has found that TJI technology can expand the lean burn limit of methane combustion to λ≈2.5, and for hydrogen, it can expand to λ≈4.5.

[0005] However, applying pre-chamber ignition to hydrogen engines also needs to overcome some technical difficulties. One of them is that hydrogen fuel is too active, and even with TJI, knocking tendency may occur at high loads because multi-point ignition and faster combustion make the end mixture reach the self-ignition condition earlier. In addition, if the pre-chamber is designed or controlled improperly, it may also cause problems such as premature dissipation of spark energy, delay in formation of flame kernel, etc., thereby affecting combustion efficiency. Current academic and industry research on pre-chamber TJI systems mainly focuses on pre-chamber structure optimization, combustion process mechanism, and injection control strategies. For example, Chen et al. found that there is an optimal balance in pre-chamber volume: increasing the volume helps to improve combustion rate but increases heat loss; Liu et al. pointed out that reducing the pre-chamber nozzle diameter can enhance jet turbulence intensity, but jet collision with the piston can cause rapid decay of turbulence. In terms of control strategies, how to optimize the fuel injection timing and quantity of the pre-chamber to form a robust flame kernel and ensure rapid flame propagation is the key to improving hydrogen lean burn stability and efficiency. The existing technology has not yet formed a mature and efficient solution for precise control and performance synergy improvement of hydrogen internal combustion engines.

[0006] There is an in-cylinder direct injection ammonia-hydrogen internal combustion engine in the prior art, which switches between pure hydrogen, small ammonia mixture, high ammonia mixture and other modes according to different working conditions, controls hydrogen and liquid ammonia injection respectively, realizes small load stable combustion, medium load high efficiency and large load knock-free operation. This scheme uses the combustion characteristics of hydrogen to improve ammonia combustion, and ensures the combustion effect under each working condition through different injection timing strategies. For example, in the prior art, in view of the problem that ammonia fuel is difficult to ignite, hydrogen is injected and ignited in the pre-chamber (jet chamber), the layered rich liquid ammonia combustion in the main combustion chamber is guided, and the liquid ammonia is injected again in the later period to absorb heat and reduce temperature, and the knock caused by hydrogen spontaneous combustion is suppressed. This method sprays hydrogen flame in the pre-chamber to cause large-area hydrogen flame, thereby improving the speed and stability of ammonia combustion, and using the second injection to achieve anti-knock control. Furthermore, there is a "based on injection ignition" hydrogen-ammonia hybrid internal combustion engine hydrogen injection control method in the prior art, which sprays hydrogen into the combustion chamber twice in each compression stroke, and ignites by a spark plug to ignite the ammonia main fuel. This method dynamically adjusts the proportion of the two hydrogen injections according to the combustion condition of the previous cycle to ensure combustion efficiency and stability.

[0007] The above technical solutions are mostly aimed at ammonia-hydrogen mixed fuel or specific working conditions, and are difficult to be directly applied to hydrogen internal combustion engines, and cannot effectively solve the core problems of poor combustion stability, high knock risk and limited thermal efficiency of hydrogen internal combustion engines when used alone.

[0008] A hydrogen internal combustion engine injection control method based on pre-chamber ignition is provided, in particular, how to use the advantages of pre-chamber ignition to control the formation and propagation of flame kernel by optimizing the timing and amount of hydrogen injection, thereby improving the stability of lean combustion, avoiding abnormal combustion and further improving the thermal efficiency of the engine. SUMMARY

[0009] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a hydrogen internal combustion engine injection control method based on pre-chamber ignition, which aims to effectively utilize the advantages of pre-chamber ignition, control the formation and propagation of flame kernel by optimizing the timing and amount of hydrogen injection, improve the stability of lean combustion, avoid abnormal combustion and further improve the thermal efficiency of the engine.

[0010] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a hydrogen internal combustion engine injection control method based on pre-chamber ignition, comprising:

[0011] When the piston is located in the range of 50-70° crank angle before the compression top dead center, hydrogen is started to be injected into the pre-chamber;

[0012] The duration of hydrogen injection in the pre-chamber is controlled to be less than 5° crank angle, so that the equivalence ratio of the pre-chamber at the time of ignition is 0.8-1.2;

[0013] The pre-chamber spark plug is triggered to ignite when the piston is close to the top dead center, so as to form a pre-chamber flame kernel within 1-5° of the crank angle after ignition;

[0014] The pre-chamber flame is injected into the main combustion chamber through a jet channel, so as to form a multi-point ignition flame kernel in the main combustion chamber and promote the combustion of the mixed gas formed by the hydrogen and air.

[0015] The pre-chamber hydrogen injection is stopped at the end of the compression stroke, and the total injection duration is not more than 100° of the crank angle before the piston bottom dead center.

[0016] The duration of the pre-chamber hydrogen injection is controlled to be 2-3° of the crank angle, and the proportion of the pre-chamber hydrogen concentration in the total fuel is increased to 0.3%-0.7%.

[0017] The pre-chamber hydrogen injection is in a multi-pulse mode, including a first injection in the intake stroke and a second injection at the end of the compression stroke.

[0018] The first injection supplies the pre-chamber with initial fuel to promote mixing, and the second injection enriches the pre-chamber mixed gas before ignition, and the equivalence ratio of the pre-chamber mixed gas is adjusted to 1.0 through the two injections.

[0019] The hydrogen fuel in the main combustion chamber is supplied in a lean mixture mode, and the air excess coefficient λ is greater than or equal to 2.5.

[0020] The hydrogen in the main combustion chamber is injected into the main combustion chamber through manifold injection or in-cylinder direct injection in the interval of 90°-360° of the crank angle before the top dead center in the intake stroke or the compression stroke, so that the total equivalence ratio of the mixed gas in the main combustion chamber at the compression top dead center is maintained within the range of 0.3-0.6.

[0021] The hydrogen injection in the main combustion chamber is single injection in each working cycle, which occurs at 180° of the crank angle before the compression top dead center, so that the hydrogen and air are fully mixed to form a uniform ultra-lean mixed gas.

[0022] A closed-loop control strategy for pre-chamber hydrogen injection and ignition is set, specifically, a pressure detection element arranged in the cylinder is used to detect combustion phase parameters, and the pre-chamber injection advance angle and fuel quantity of the next working cycle are automatically corrected based on the characteristic value of the combustion pressure of the last working cycle.

[0023] When it is detected that the combustion center position of the last cycle is later than the target value, the pre-chamber injection advance angle is increased by 5°-10° of the crank angle, or the hydrogen injection quantity is increased by 5%-15%; when it is detected that the combustion center position is earlier than the target value, or the knocking trend is detected, the pre-chamber injection advance angle is reduced by 5°-10° of the crank angle, or the injection quantity is reduced by 5%-15%.

[0024] The present application also provides an engine system, comprising at least one cylinder, a piston, a main combustion chamber, a pre-chamber connected with the main combustion chamber, a spark plug and a hydrogen fuel injector arranged in the pre-chamber, an electronic control unit and a sensor assembly, wherein the electronic control unit is used to execute the hydrogen internal combustion engine injection control method, and the sensor assembly comprises an in-cylinder pressure detection element and a knock detection element, and is arranged to feed back signals to the electronic control unit to realize closed-loop control of pre-chamber injection and ignition.

[0025] The pre-chamber is connected with the main combustion chamber through a plurality of radially distributed jet holes, each jet hole has a diameter of 1-3 mm, the number of jet holes is 4-8, and each jet hole is directed towards a different area in the main combustion chamber to realize multi-point ignition of the lean mixture in the main combustion chamber.

[0026] The hydrogen fuel injector comprises a high-pressure hydrogen supply source and a direct injection nozzle, and the injection pressure is 5-15 MPa.

[0027] The pre-chamber fuel injector adopts an electromagnetic control injector or a piezoelectric control injector.

[0028] When the hydrogen supply mode of the main combustion chamber is manifold injection, a plurality of direct injection nozzles are arranged on the intake manifold.

[0029] Alternatively, when the hydrogen supply mode of the main combustion chamber is in-cylinder direct injection, a direct injection nozzle is additionally arranged on the top of each cylinder.

[0030] The present application is based on the hydrogen internal combustion engine injection control method based on pre-chamber ignition, and through optimization of the timing, duration and control strategy of pre-chamber fuel injection and cooperation of the corresponding sensing and feedback adjustment mechanism, stable and rapid ignition and flame propagation of hydrogen lean combustion are realized, the lean burn limit is widened, the NOx emission is reduced, and the thermal efficiency of the engine is significantly improved. Therefore, the technical problems of poor combustion stability, high risk of knock and pre-ignition and limited thermal efficiency of the existing hydrogen lean internal combustion engine are overcome. BRIEF DESCRIPTION OF DRAWINGS

[0031] The present specification includes the following drawings, and the contents shown are as follows:

[0032] Figure 1 is a structural schematic diagram of the engine system of the present application;

[0033] Figure 2a and Figure 2b is a comparison diagram of in-cylinder pressure and heat release rate of the pre-chamber ignition hydrogen engine under different loads;

[0034] Figure 3a and Figure 3bis a curve chart of the influence of start of injection (SOI) of the pre-chamber hydrogen injection on the combustion characteristics;

[0035] Figure 4 is a schematic diagram of selected cross-section positions for analyzing the pre-chamber flow field;

[0036] Figure 5 is a comparative schematic diagram of the hydrogen concentration distribution and flow field in the pre-chamber and the main combustion chamber under different pre-chamber injection start point (SOI) conditions

[0037] Figure 6 is a conceptual layout schematic diagram of an engine test bench;

[0038] marked as in the figure:

[0039] 1, spark plug; 2, hydrogen injector; 3, injection hole;

[0040] 4, data collector; 5, turbocharger; 6, intercooler; 7, pre-chamber; 8, hydrogen rail; 9, intake pipe; 10, dynamometer; 11, hydrogen tank; 12, flame arrester; 13, hydrogen flowmeter; 14, pressure reducing valve; 15, solenoid valve; 16, computer; 17, exhaust pipe. DETAILED DESCRIPTION

[0041] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings, and the purpose of the description of the embodiments with reference to the accompanying drawings is to help the person skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present application, and to help the implementation thereof.

[0042] In a first aspect, the embodiment of the present application provides a hydrogen internal combustion engine injection control method based on pre-chamber ignition, which is used for a hydrogen internal combustion engine with a pre-chamber to realize stable ignition of lean combustion,

[0043] characterized in that: a part of hydrogen fuel is quantitatively injected into the pre-chamber during the compression stroke of each working cycle, and the hydrogen mixture in the pre-chamber is ignited near the top dead center to produce a high-speed flame jet to ignite the lean hydrogen mixture in the main combustion chamber.

[0044] The hydrogen internal combustion engine injection control method based on pre-chamber ignition provided by the embodiment of the present application comprises the following steps:

[0045] When the piston is located in the range of 50-70° crank angle before the compression top dead center, hydrogen injection to the pre-chamber is started;

[0046] The duration of the pre-chamber hydrogen injection is controlled to be less than 5° crank angle, so that the equivalence ratio of the pre-chamber at the time of ignition is 0.8-1.2;

[0047] The pre-chamber spark plug is triggered to ignite when the piston is close to the top dead center (TDC) (within 10°CA before and after TDC), to form a pre-chamber flame kernel within 1-5°CA after ignition;

[0048] The pre-chamber flame is injected into the main combustion chamber through the jet channel, to form a multi-point ignition flame kernel in the main combustion chamber and to promote the combustion of the mixture of hydrogen and air.

[0049] The pre-chamber hydrogen injection is stopped at the end of the compression stroke, and the total injection duration is no more than 100°CA before the piston bottom dead center (BDC).

[0050] Specifically, in the embodiments of the present application, a hydrogen internal combustion engine injection control method based on pre-chamber ignition is provided, which is applied to a hydrogen-fueled internal combustion engine system with a pre-chamber. The internal combustion engine comprises a main combustion chamber and a pre-chamber in communication with the main combustion chamber, a spark plug is arranged in the pre-chamber for ignition, and a hydrogen fuel injector is arranged in the pre-chamber and / or the main combustion chamber. The method achieves control through the following steps:

[0051] 1. Pre-chamber fuel distribution and mixing: In the compression stroke of each working cycle, a portion of hydrogen fuel is quantitatively injected into the pre-chamber to form ignitable combustible mixture. The pre-chamber hydrogen injection adopts direct injection, and the injection is preferably started at a specific crank angle interval during the piston compression upstroke. The start of injection (SOI) is set between 50°-70°CA before the piston top dead center (TDC), to ensure that the pre-chamber has sufficient hydrogen mixture at the ignition time. For example, when the SOI is set to about 60°CA before TDC, the pre-chamber can obtain a uniform and moderately rich mixture, which is beneficial to the rapid formation of the flame kernel.

[0052] 2. Pre-chamber injection duration and pulse control: The duration of pre-chamber hydrogen injection (DOI) is controlled, so that the single injection lasts for less than a predetermined crank angle range (for example, less than 5°CA). The preferred injection duration is about 2°CA-3°CA, at which the amount of hydrogen obtained by the pre-chamber accounts for 0.3%-0.7% of the total fuel, which can significantly accelerate the formation of the flame kernel and increase the jet flame intensity. Experiments show that increasing the pre-chamber injection duration from 1°CA to 2°CA can stabilize the flame kernel and accelerate the flame propagation in the main combustion chamber, while further increasing to 4°CA will cause the ignition delay to become longer due to the disturbance of the flow field in the pre-chamber. Therefore, the present method limits the amount of pre-chamber single injection to be moderate, to avoid excessive hydrogen injection causing excessive dissipation of spark energy. In other embodiments, the pre-chamber injection can adopt a multi-pulse mode, for example, one hydrogen injection in the intake stroke and one in the compression stroke, to improve the temporal and spatial distribution of the pre-chamber mixture concentration. Specifically, a small amount of hydrogen is injected in the first pulse during the intake process to pre-mix a small amount of fuel, and a major amount of hydrogen is injected in the second pulse at the end of the compression stroke, so that the ideal equivalence ratio (close to stoichiometric ratio) is achieved in the pre-chamber before ignition.

[0053] 3. Main combustion chamber lean mixture supply: The remaining majority of hydrogen fuel is supplied to the main combustion chamber to form a lean mixture, with more hydrogen entering the main combustion chamber than the pre-chamber. The hydrogen in the main combustion chamber can be introduced by port fuel injection (PFI) or direct injection (DI). In the preferred embodiment, the hydrogen injector injects hydrogen into the main combustion chamber one or more times during the early intake or compression stroke (e.g. 90°-360° CA before top dead center). This ensures that a uniform lean mixture is formed in the main combustion chamber before compression ignition. The lean mixture preferably has an air excess ratio λ greater than 2.5 to significantly reduce NOx formation. By distributing the fuel as described above between the pre-chamber and the main combustion chamber, the present application implements a "pre-chamber rich + main combustion chamber lean" split charge strategy: the near-stoichiometric mixture in the pre-chamber ensures reliable ignition, while the ultra-lean mixture in the main combustion chamber enables ultra-low NOx combustion.

[0054] 4. Ignition timing control: The pre-chamber is ignited by the spark plug when the piston is near the compression top dead center. The ignition timing is optimally controlled according to engine operating conditions, and is generally set near the top dead center (e.g. within a few degrees after top dead center). Preferably, the ignition is completed within about 7° CA after top dead center, after the pre-chamber injection is completed. This allows the mixture in the pre-chamber to be sufficiently swirled without being diluted too much, so that a stable flame kernel is quickly formed within 1-5° CA after ignition. For example, with SOI = 90° CA BTDC (Before Top Dead Center), a flame kernel appears about 1° CA after ignition; with SOI = 50° CA BTDC, a flame kernel forms about 4° CA after ignition; and with SOI = 30° CA BTDC, a clear flame kernel forms about 12° CA after ignition. Therefore, by choosing an appropriate ignition advance angle in conjunction with the injection strategy described above, a flame kernel can be ensured to appear in time and be sufficiently robust.

[0055] 5. Jet flame propagation: The high-temperature and high-pressure flame generated by hydrogen combustion in the pre-chamber is ejected through the jet holes between the pre-chamber and the main combustion chamber, forming multiple flame jet cores in the main combustion chamber. With the help of strong turbulent disturbance and multi-point ignition of the jet, the lean hydrogen mixture in the main combustion chamber is quickly ignited and forms a flame front that spreads from multiple ignition points to the surrounding. By optimizing the layout of the pre-chamber jet channel (such as hole diameter and number) and the direction of the jet, the invention ensures that the flame jet can cover most of the area of the main combustion chamber, achieving uniform and rapid combustion. Test results show that under different pre-chamber injection conditions, the main combustion duration from ejection to reaching the cylinder wall is in the range of about 11°CA~15°CA, which is closely related to the intensity and coverage of the jet flame. By increasing the hydrogen concentration in the pre-chamber and appropriately increasing the jet kinetic energy, the flame propagation speed in the main combustion chamber can be accelerated. For example, when the hydrogen concentration in the pre-chamber is increased (corresponding to longer injection duration or larger injection amount), the main combustion period can be shortened from 14°CA to 12°CA. However, it is necessary to avoid excessive jet speed that may cause local strong turbulent flow to wash away the spark, hindering the formation of flame cores.

[0056] 6. Feedback control and adaptive adjustment: The injection control system of the invention is equipped with sensors and an electronic control unit (ECU) to achieve closed-loop feedback control. Preferably, a high-speed pressure sensor is installed on the engine cylinder to monitor the combustion pressure curve of each working cycle (each working cycle refers to the period of a complete energy conversion process of the hydrogen internal combustion engine, specifically corresponding to one working cycle of the internal combustion engine, including four consecutive strokes of intake, compression, work, and exhaust). The ECU adjusts the pre-chamber injection time and injection amount of the next cycle according to the feedback combustion indicators (such as ignition delay, combustion duration CA10-CA90, pressure peak position CA50, cycle variation rate, etc.). For example, if the ignition delay of the previous cycle is detected to be too long, the ECU can appropriately advance the pre-chamber injection time or increase the injection amount; if the combustion is too fast or there is a tendency to knock, the ignition can be slightly delayed or the pre-chamber fuel amount can be reduced to alleviate it. In particular, when switching between different operating conditions (such as from low load to high load), the control system can use a self-learning algorithm (such as LSTM long short-term memory neural network) based on historical data to predict the optimal injection parameters, reducing the impact of sensor response lag on control. Through the above closed-loop correction mechanism, the pre-chamber injection parameters are always maintained within the optimal range, adapting to changes in engine load, speed, and environment, ensuring the sustained stability and efficiency of hydrogen lean-burn combustion.

[0057] As a preferred, the control pre-chamber hydrogen injection duration is 2~3° crank angle, and the pre-chamber hydrogen concentration ratio is increased to 0.3%~0.7% of the total fuel, thereby accelerating the formation of flame cores and increasing the intensity of jet flame.

[0058] In the embodiment of the present application, the injection of hydrogen in the pre-chamber is in multiple pulses, including a first injection in the intake stroke and a second injection at the end of the compression stroke; wherein the first injection supplies the pre-chamber with initial fuel to promote mixing, and the second injection enriches the pre-chamber mixture before ignition, and the equivalence ratio of the pre-chamber mixture is adjusted to 1.0 by the two injections. The amount of hydrogen injected in the pre-chamber for the first time is less than the amount of hydrogen injected in the pre-chamber for the second time, a small amount of hydrogen is injected during the intake process to premix a small amount of fuel, and the second injection sprays the main amount of hydrogen at the end of compression, so that the ideal equivalence ratio in the pre-chamber is achieved before ignition.

[0059] The start time of the hydrogen injection in the pre-chamber is defined as the second pre-chamber injection at the end of the compression stroke, followed by ignition immediately after the completion of the second pre-chamber injection, and the ignition time is within 0-5°CA after the end of the second injection, so that efficient ignition is achieved by using the instantaneous optimal state of the mixture after injection.

[0060] In the embodiment of the present application, the hydrogen fuel in the main combustion chamber is supplied in a lean mixture mode, and the air excess coefficient λ≥2.5;

[0061] The supply mode of hydrogen in the main combustion chamber is: in the 90°-360° crank angle interval before the top dead center of the intake or compression stroke, hydrogen is injected into the main combustion chamber through manifold injection or in-cylinder direct injection, so that the total equivalence ratio of the mixture in the main combustion chamber at the compression top dead center is maintained within the range of 0.3-0.6.

[0062] In the embodiment of the present application, the hydrogen injection in the main combustion chamber is single injection in each working cycle, which occurs at 180° crank angle before the compression top dead center, so that hydrogen and air are fully mixed to form a uniform ultra-lean mixture.

[0063] In the embodiment of the present application, a closed-loop control strategy for pre-chamber hydrogen injection and ignition is provided, which specifically includes: detecting combustion phase parameters using a pressure detection element arranged in the cylinder, automatically correcting the pre-chamber injection advance angle and fuel quantity of the next working cycle based on the characteristic value of the combustion pressure of the last working cycle, and the combustion pressure characteristic value includes ignition delay (usually in units of crank angle “°CA”), CA50 (combustion center position), and pressure rise rate, etc.;

[0064] When it is detected that the combustion center position of the last cycle is later than the target value, the pre-chamber injection advance angle is increased by 5°-10° crank angle, or the hydrogen injection amount is increased by 5%-15%;

[0065] When it is detected that the combustion center position is earlier than the target value or a knocking trend is detected, the pre-chamber injection advance angle is reduced by 5°-10° crank angle, or the injection amount is reduced by 5%-15%, so as to maintain the optimal combustion phase.

[0066] In a second aspect, the embodiments of the present application provide an engine system, which comprises at least one cylinder, a cylinder head, a piston, a main combustion chamber, a pre-chamber connected with the main combustion chamber, the pre-chamber being arranged in the cylinder head, the pre-chamber being provided with a spark plug and a hydrogen fuel injector, the engine system further comprising an electronic control unit and a sensor assembly, the electronic control unit being electrically connected with the hydrogen fuel injector, the spark plug, the sensor assembly and the like, the electronic control unit being used to execute the hydrogen internal combustion engine injection control method of the above-mentioned embodiments, the sensor assembly comprising an in-cylinder pressure detection element and a knock detection element, the sensor assembly being arranged to feed back signals to the electronic control unit, so as to realize closed-loop control of pre-chamber injection and ignition.

[0067] As shown in Figure 1 FIG. 1 is a structural schematic diagram of an engine system of the present application, which shows an engine cylinder body geometry and a cylinder head model with a pre-chamber, wherein the pre-chamber is arranged in the cylinder head and connected with the main combustion chamber through jet holes.

[0068] In the embodiments of the present application, the pre-chamber is connected with the main combustion chamber through a plurality of radially distributed jet holes, each jet hole having a diameter of 1-3 mm, the number of jet holes being 4-8, the opening direction of each jet hole being directed to different regions in the main combustion chamber, so as to realize multi-point ignition of the lean mixture in the main combustion chamber. The axis direction of the jet hole extends along the radial direction of the pre-chamber, i.e. the jet hole is arranged outward from the vicinity of the central axis of the pre-chamber, so that the pre-chamber is connected with the main combustion chamber through these radial holes, the jet holes are uniformly arranged around the spark plug, so that the jet flame can be shot to each main region of the main combustion chamber. The electrode position of the spark plug is arranged relative to the jet hole of the pre-chamber, so that the ignition kernel directly contacts the hydrogen-rich mixture in the pre-chamber and avoids being extinguished by high-speed jet.

[0069] In the embodiments of the present application, the volume of the pre-chamber accounts for 1-5% of the compression top dead center volume of the main combustion chamber (i.e. the total volume of the main combustion chamber at the end of the compression stroke), the electrode of the spark plug is located in the center of the pre-chamber and slightly biased to the direction of the jet hole, so as to avoid the influence of high-speed jet on the spark extinguishing; the material and structure design of the pre-chamber can withstand high-temperature high-speed jet scouring and reduce heat loss.

[0070] In the embodiments of the present application, the sensor assembly further comprises an exhaust oxygen sensor and a temperature sensor, the ECU adjusts the hydrogen injection amount of the main combustion chamber based on the air-fuel ratio information fed back by the oxygen sensor, so as to maintain the air excess coefficient in a preset range, thereby taking into account the combustion stability and low NOx emission; based on the cylinder head or exhaust temperature monitored by the temperature sensor, the ECU can appropriately increase the inert gas (such as CO2 or N2) in the pre-chamber injection or adopt a rich strategy to protect the engine components during high-temperature period.

[0071] In the embodiment of the present application, the hydrogen fuel injector comprises a high-pressure hydrogen supply source and a direct injection nozzle, the hydrogen fuel injector adopts high-pressure hydrogen supply, and the injection pressure is 5-15 MPa, so as to ensure good atomization effect.

[0072] The hydrogen fuel injector arranged on the pre-chamber can adopt an electromagnetic control injector or a piezoelectric control injector, the piezoelectric control injector can obtain more precise injection amount control; when the hydrogen supply mode of the main combustion chamber is manifold injection, a plurality of injection nozzles are arranged on the intake manifold; or, when the hydrogen supply mode of the main combustion chamber is direct injection in the cylinder, a direct injection nozzle is additionally arranged on the top of each cylinder.

[0073] When the engine is in a high load condition (at this time, the engine load is greater than or equal to 70%), a small amount of hydrogen or inert gas is injected into the main combustion chamber (for example, the amount of hydrogen or inert gas injected accounts for less than 5% of the total fuel mass), so as to absorb heat and cool, and create an anti-knock environment.

[0074] The volume of the pre-chamber and the size of the injection hole are designed according to the engine displacement, the volume is about 2%-5% of the volume of the main combustion chamber after compression, and the diameter and total cross-sectional area of the injection hole are ensured to ensure that the jet penetrates the combustion chamber without excessive heat loss.

[0075] Fig. 2 is a comparison diagram of in-cylinder pressure and heat release rate of the pre-chamber ignition hydrogen engine under different loads: (a) BMEP = 2 bar medium load; (b) BMEP = 5 bar higher load. The solid line in the figure is the simulation result, and the symbol is the test measured value.

[0076] Fig. 3 is a curve diagram of the influence of the start of injection (SOI) of the pre-chamber hydrogen injection on the combustion characteristics: (a) the relationship between the ignition delay, the combustion duration and the combustion phase (CA50) and the SOI; (b) the change trend of the hydrogen amount per specific power consumption and the indicated thermal efficiency (ITE) under different SOI.

[0077] Figure 4 Fig. 4 is a schematic diagram of selected cross-sectional positions for analyzing the flow field of the pre-chamber. The red plane represents a horizontal cross-section, and the blue plane represents a vertical cross-section, which is used to show the concentration and flow distribution inside the pre-chamber at different injection times.

[0078] Figure 5 Fig. 5 is a comparison diagram of the hydrogen concentration distribution and flow field in the pre-chamber and the main combustion chamber under different pre-chamber injection start point (SOI) conditions. Each group of diagrams corresponds to one SOI condition, and shows that the higher the hydrogen concentration in the pre-chamber at the ignition time, the greater the jet intensity.

[0079] The hydrogen internal combustion engine injection control method and the engine system based on the pre-chamber ignition provided by the embodiment of the present application have the following beneficial effects:

[0080] 1. Significant improvement in lean combustion stability: By means of pre-chamber multi-point jet ignition, the present invention can extend the equivalence ratio of hydrogen lean burn operation to λ≈3.0 or even higher, while maintaining reliable ignition and stable combustion. The ultra-lean mixture in the main combustion chamber is simultaneously ignited by multiple jet flame kernels, which burn rapidly and uniformly, avoiding the problems of incomplete combustion and increased cycle-to-cycle variation that are prone to occur in traditional single spark ignition under lean conditions. Experimental results show that the hydrogen engine with pre-chamber TJI can still operate smoothly in the range of λ=3-4, with significantly reduced NOx emissions and good combustion stability.

[0081] 2. Improved combustion speed and shortened combustion duration: The pre-chamber flame jet significantly enhances the turbulence intensity and flame propagation speed in the main combustion chamber, resulting in a significant reduction in total combustion duration. By optimizing the pre-chamber injection strategy, the CA10-CA90 combustion duration can be shortened to about 10°CA. For example, when the pre-chamber injection advance angle is 70°CA BTDC, the shortest measured combustion duration is about 9.8°CA. The acceleration of combustion allows the optimal combustion center (CA50) to be reached in time, releasing more expansion work while maintaining cycle stability. In contrast, single spark plug ignition often has a significantly prolonged combustion duration under extremely lean conditions, and the present invention effectively overcomes this shortcoming.

[0082] 3. Reduced ignition delay: By regulating the mixture concentration and flow field in the pre-chamber, the present invention significantly shortens the ignition delay (the interval between CA0 and CA10) after spark ignition. Optimized pre-chamber injection timing (such as 50°-70° BTDC) can shorten the ignition delay to within 10°CA, while late injection (30° BTDC) can have an ignition delay of up to about 17°CA. The shortening of ignition delay means that the flame kernel appears earlier, and the combustion phase is closer to top dead center, which helps to improve expansion work efficiency and reduce the risk of unburned mixture knock at high loads.

[0083] 4. Improved thermal efficiency: Due to the optimal combustion phase, shortened combustion duration, and reduced heat loss under lean conditions, the thermal efficiency of the engine is significantly improved. Simulation and experimental results show that the present invention can achieve a brake thermal efficiency (BTE) of up to about 47% at the optimal injection timing (about 50° BTDC). Within a wide range of pre-chamber injection duration (DOI 1°-3°CA), the indicated thermal efficiency (ITE) of the engine remains above 46.8%. Compared to the baseline hydrogen engine without a pre-chamber, which has a thermal efficiency of about 42%, the thermal efficiency of the engine of the present invention can be increased by about 5 percentage points. In addition, due to the reduction of in-cylinder heat loss and compression work loss under ultra-lean operation, the thermal efficiency under part-load conditions is more significantly improved.

[0084] 5. Significant reduction of NOx emissions: With the help of pre-chamber ignition to support ultra-lean combustion, the present application can control NOx emissions at a very low level or even close to zero without additional aftertreatment. When λ > 2.5, the high-temperature thermal NOx generation is almost negligible, and the strong disturbance of the pre-chamber jet also helps to reduce the formation of local high-temperature hot spots. Compared with traditional lean-burn ignition, which needs to work at a lower air excess coefficient to maintain stable combustion, the present application can achieve stable combustion under higher excess air conditions, thereby inhibiting NOx from the source. Since hydrogen combustion itself does not produce soot, carbon monoxide and hydrocarbon emissions are also very low, so the present application is expected to achieve clean combustion with near-zero pollutant emissions.

[0085] 6. Suppression of knock and avoidance of backfire: Pre-chamber jet ignition reduces the knock tendency on the one hand by dilution, and on the other hand by multi-point ignition, which shortens the flame propagation path and reduces the residence time of unburned mixture at the end, thereby reducing the possibility of knock. In addition, the present application method sets up a jet hole between the pre-chamber and the main combustion chamber as a flame isolation, which to some extent prevents the flame from returning to the intake pipe and avoids the backfire phenomenon. For high load conditions, the present application can cooperate with the second fuel injection (such as injecting a small amount of hydrogen or inert medium into the main combustion chamber later) to absorb heat and cool down, creating an anti-knock environment. Tests show that compared with pure hydrogen single-stage direct injection, the engine using the pre-chamber multi-stage injection ignition strategy runs more smoothly under high pressure and high temperature conditions without knock.

[0086] 7. Self-adaptive control to improve reliability: The present application introduces sensor feedback and intelligent control algorithm, so that the injection parameters can be adjusted in real time, greatly enhancing the adaptability to environmental changes and engine aging. The various sensors (pressure, temperature, knock, etc.) work together to use the predictive control model to correct the injection strategy in advance, avoiding the control lag caused by the inconsistent response of multiple sensors. Therefore, whether the engine is cold-starting, changing load or long-running, the present application system can automatically maintain the best injection and ignition settings, ensuring the reliability and efficiency of the combustion process. This adaptive injection control greatly reduces the tuning workload and improves the robustness of the system.

[0087] Example 1

[0088] In this embodiment, the pre-chamber single-time hydrogen direct injection control method is used.

[0089] Figure 1The engine in this example is a single-cylinder hydrogen-fueled internal combustion engine, which consists of a main combustion chamber and a pre-chamber. The pre-chamber is located above the cylinder head and is connected to the main combustion chamber through six 1.5 mm diameter jet holes. An electric spark plug is installed in the center of the pre-chamber. A hydrogen direct injection nozzle is installed on the side wall of the pre-chamber, pointing towards the area near the spark plug electrode. The main combustion chamber is supplied with hydrogen through the intake port (port injection) to form a homogeneous lean mixture. The engine is equipped with in-cylinder pressure and knock sensors, which transmit signals to the electronic control unit (ECU).

[0090] In this example, the ECU controls hydrogen injection and ignition according to the following strategy: In each working cycle, the piston rises from bottom dead center to top dead center during the compression stroke. When the crank angle is about 60° before top dead center (SOI = 60° BTDC), the ECU triggers the pre-chamber direct injection nozzle to start injecting hydrogen. The nozzle instantaneously injects a fixed amount of hydrogen at a pressure of about 10 MPa, with an injection duration of about 2.5° CA, stopping at about 57.5° before top dead center. In this way, a hydrogen-air mixture with an equivalence ratio of about Φ ≈ 1.2 (slightly richer than stoichiometric to enhance the flame) is formed in the pre-chamber at the end of compression. At the same time, the amount of hydrogen supplied to the main combustion chamber through the intake manifold is adjusted so that the overall equivalence ratio of the main combustion chamber is about Φ ≈ 0.5 (i.e., the air excess ratio λ ≈ 2.0) at compression, representing an extremely lean mixture.

[0091] When the piston approaches top dead center (about 5° after top dead center, i.e., at crank angle 355° CA), the ECU triggers the spark plug to ignite. Due to the high hydrogen concentration in the pre-chamber and the appropriate turbulence arrangement, a clear visible flame kernel appears only about 3° CA after spark discharge. The flame kernel rapidly expands, filling the entire pre-chamber in 0.0005 s, causing a sudden increase in pressure. As the pre-chamber pressure exceeds that of the main combustion chamber, the high-temperature combustion products are ejected into the main combustion chamber through the jet holes, forming six high-speed jet flames. At this time, the piston has just passed top dead center and is beginning to descend, and the ultra-lean hydrogen-air mixture in the main combustion chamber is ignited almost simultaneously by the multiple jet flames. Due to the multi-point ignition and strong turbulent disturbance, the combustion in the main combustion chamber rapidly and nearly simultaneously spreads everywhere. According to the data recorded by the pressure sensor, 50% of the combustion heat release (CA50) is reached in the main combustion chamber about 12° CA after ignition (i.e., about 12° after top dead center), indicating that the combustion phase is close to optimal. About 11° CA later (around 23° CA after top dead center), the cylinder pressure reaches a peak of 3.5 MPa, and 90% of the combustion is completed (CA90).

[0092] Compared with the same engine without pre-chamber ignition, the present embodiment achieves robust and fast combustion at equivalence ratio Φ ≈ 0.5, with ignition delay (CA10) of only about 5°CA, while conventional spark ignition often fails to ignite or requires > 15°CA to reach CA10 at such lean mixture; combustion duration (CA10-90) is about 18°CA, much shorter than ordinary spark ignition (usually > 40°CA). Moreover, the engine's indicated thermal efficiency at this operating condition reaches 45.6%, about 10 percentage points higher than the baseline condition, and the exhaust gas contains nearly zero NOx, with only trace amounts of NO and NO2 generated.

[0093] During operation, the ECU continuously monitors combustion characteristics using the pressure sensor signal. When it detects that the combustion center (CA50) of a certain cycle deviates from the target value of 8°CA after top dead center, the ECU will adjust the injection or ignition of the next cycle according to the deviation: for example, if CA50 is delayed to 12°CA, the pre-chamber injection is appropriately advanced to 62°BTDC; if CA50 is advanced to 4°CA, the pre-chamber injection amount is slightly reduced to slow down combustion. Through this inter-cycle adaptive correction, the engine can maintain the optimal combustion phase under different speed and load conditions. After long-term testing and verification, the system in this embodiment runs smoothly within the range of 1200-3000 rpm and IMAP (indicated mean effective pressure) 2-8 bar, without knocking or backfiring, with a cycle variation coefficient COV(IMEP) maintained below 2%, showing excellent combustion stability and adaptability.

[0094] Example 2

[0095] In this embodiment, the pre-chamber double-pulse injection and stratified ignition control are targeted.

[0096] This embodiment targets larger-bore, multi-cylinder hydrogen-fueled engines, using a pre-chamber double-pulse injection strategy to further improve combustion control under high load. The engine structure is as shown in Figure 1 , but the pre-chamber nozzle is replaced with a two-stage injection capability (double solenoid valves controlled by the ECU). The hydrogen supply to the main combustion chamber uses in-cylinder direct injection to facilitate accurate control of hydrogen concentration at different stages.

[0097] At low and medium loads, the present embodiment can degenerate into the control scheme of Embodiment 1. At high loads (e.g. BMEP > 8 bar), the ECU performs double-pulse injection control: first, a first injection of hydrogen into the pre-chamber is performed at the late intake stroke (about 30°CA before intake valve closing), with about 30% of the total pre-chamber fuel being hydrogen. Since the in-cylinder pressure is low at this time, the pressure difference between the pre-chamber and the main combustion chamber is small, and a portion of the hydrogen diffuses into the main combustion chamber with the air flow, but a considerable proportion remains in the pre-chamber to form a pre-mixed hydrogen layer. Subsequently, a second injection into the pre-chamber is performed at the end of the compression stroke (about 50°CA before top dead center), with the remaining about 70% of the hydrogen, i.e. about 70% of the total pre-chamber fuel, being injected, so that the hydrogen equivalence ratio in the pre-chamber reaches about 1.0. The second injection is performed close to the end of the compression stroke, so that most of the hydrogen remains in the pre-chamber, and because the initial concentration in the pre-chamber is increased by the hydrogen left over from the first pulse, the mixture in the pre-chamber is very rich and uniformly distributed at this time. Ignition is then performed at about 10°CA before top dead center, and a strong flame is rapidly generated in the pre-chamber. Compared with Embodiment 1, double-pulse injection causes a layer of pilot flame to exist in the pre-chamber before ignition (a small amount of burned hydrogen formed by the first pulse begins to pre-combust, but is not ignited), and the second pulse strengthens this pilot flame. When the spark ignites, a large-area flame kernel is more quickly formed in the pre-chamber, and the jet flame is also higher in speed and temperature. The main combustion chamber is rapidly combusted under the action of the jet flame. In the case of high loads and large fuel quantities, this strategy can effectively prevent spark extinguishment or jet deficiency caused by a single large injection, while ensuring the combustion rate. Tests show that, under the condition of BMEP ≈ 12 bar, using this strategy, the engine does not appear to knock, and the second derivative of the cylinder pressure has no abnormal peak, proving that the combustion is stable and controlled. In addition, because the intensity of the jet flame is increased, the duration of the main combustion chamber combustion is shortened by about 20% compared with single-pulse injection, so that high-load combustion can also be maintained at a phase close to top dead center, avoiding excessive dwell combustion that leads to a decrease in efficiency.

[0098] Embodiment 3

[0099] In the present embodiment, the pre-chamber fuel ratio and feedback control are targeted.

[0100] The present embodiment investigates the influence of the fuel ratio in the pre-chamber on combustion and realizes optimization through closed-loop control. The engine structure is the same as that in Embodiment 1. The ratio of the fuel in the pre-chamber to the total hydrogen supply is set as a variable parameter, which is automatically adjusted by the ECU according to the target working condition. In the steady state working condition, it is known through experiments that when the hydrogen amount in the pre-chamber accounts for about 1% of the total fuel (a very small ratio), the pre-chamber flame is not sufficient to fully ignite the ultra-lean mixture in the main combustion chamber, resulting in a long ignition delay (about 13°CA) and a rough combustion; when the pre-chamber ratio is increased to 5%, the ignition delay is significantly shortened, but the jet effect is enhanced, leading to a too fast combustion and even a slight tendency to knock; when the pre-chamber ratio is in the range of about 2% to 3%, the combustion delay, rate and stability are the best. Based on this, the present embodiment sets the pre-chamber fuel basis as 2.5% of the total fuel.

[0101] The ECU controls this ratio in real time through feedback: at the end of each working cycle, the actual CA50 position is calculated according to the data collected by the pressure sensor, and compared with the target value.

[0102] If CA50 is later than the target value, it means that the combustion is too slow, and the pre-chamber fuel ratio K% can be increased, for example, the hydrogen injection amount in the pre-chamber is increased by 5% to 15% during the next working cycle; if CA50 is earlier than the target value or there are signs of knock, then the pre-chamber fuel K% is reduced, for example, the hydrogen injection amount in the pre-chamber is reduced by 5% to 15% during the next working cycle. Here, K is given by an empirical matrix or an online model, or predicted by a machine learning algorithm according to historical data. After several cycle iterations, the pre-chamber fuel ratio gradually approaches the optimal value. In actual tests, when the speed or load fluctuates, this self-adjusting mechanism can quickly pull the combustion phase back to normal. For example, when the throttle opening is suddenly increased, causing the mixture to become dense and the combustion to speed up, CA50 is advanced to 2°CA, the ECU reduces the pre-chamber fuel ratio from 2.5% to 1.8% in the next cycle, and as a result, CA50 is adjusted back to 6°CA, and the combustion returns to normal. Conversely, if the load is reduced, causing CA50 to be delayed, the ECU increases the pre-chamber injection ratio to strengthen the ignition. As can be seen, through the feedback control of the pre-chamber fuel distribution, the present embodiment realizes intelligent optimization under different working conditions, eliminates the tediousness of manual calibration, and improves the adaptability and robustness of the system.

[0103] The above describes the present application by way of example with reference to the drawings. Obviously, the specific implementation of the present application is not limited to the above-described manner. As long as various non-essential improvements are made using the inventive concept and technical solution, or the above-described concept and technical solution of the present application is directly applied to other occasions without improvement, they are all within the protection scope of the present application.

Claims

1. A hydrogen internal combustion engine injection control method based on prechamber ignition, characterized by, The application relates to a hydrogen internal combustion engine system and a hydrogen internal combustion engine injection control method. The hydrogen injection into the precombustion chamber is started when the piston is located in a 50-70-degree crank angle range before the compression top dead center; The hydrogen injection duration into the precombustion chamber is controlled to be less than 5 degrees of crank angle, so that the equivalence ratio of the precombustion chamber at the time of ignition is 0.8-1.2; The precombustion chamber spark plug is triggered to ignite when the piston approaches the top dead center, so that a precombustion chamber flame core is formed within 1-5 degrees of crank angle after ignition; The precombustion chamber flame is injected into the main combustion chamber through the jet channel, so that a multi-point ignition flame core is formed in the main combustion chamber and the mixed gas formed by mixing hydrogen and air is combusted; The hydrogen injection into the precombustion chamber is stopped at the end of the compression stroke, and the total injection duration is not more than 100 degrees of crank angle before the piston bottom dead center.

2. The pre-chamber ignition-based hydrogen internal combustion engine injection control method according to claim 1, characterized by, The hydrogen injection duration into the precombustion chamber is controlled to be 2-3 degrees of crank angle, and the hydrogen concentration ratio in the precombustion chamber is increased to 0.3%-0.7% of the total fuel.

3. The pre-chamber ignition-based hydrogen internal combustion engine injection control method according to claim 1, characterized by, The hydrogen injection into the precombustion chamber is in a multi-pulse mode, including first injection in the intake stroke and second injection at the end of the compression stroke; The first injection supplies initial fuel to the precombustion chamber to promote mixing, and the second injection enriches the precombustion chamber mixed gas before ignition, and the equivalence ratio of the precombustion chamber mixed gas is adjusted to 1.0 through the two injections.

4. The pre-chamber ignition-based hydrogen internal combustion engine injection control method according to any one of claims 1 to 3, characterized by, The hydrogen fuel in the main combustion chamber is supplied in a lean mixture mode, and the air excess coefficient lambda is greater than or equal to 2.

5. The hydrogen supply mode of the main combustion chamber is that the hydrogen is injected into the main combustion chamber through manifold injection or in-cylinder direct injection in a 90-360-degree crank angle range before the top dead center of the intake stroke or the compression stroke, so that the total equivalence ratio of the mixed gas in the main combustion chamber at the compression top dead center is kept in the range of 0.3-0.

6.

5. The pre-chamber ignition-based hydrogen internal combustion engine injection control method according to claim 4, characterized by, The hydrogen injection into the main combustion chamber is single injection in each working cycle and occurs at 180 degrees of crank angle before the compression top dead center, so that the hydrogen and air are fully mixed to form uniform ultra-lean mixed gas.

6. The pre-chamber ignition-based hydrogen internal combustion engine injection control method according to any one of claims 1 to 3, characterized by, A closed-loop control strategy of the hydrogen injection into the precombustion chamber and ignition is arranged, and the strategy is as follows: a pressure detection element arranged in the cylinder is used to detect the combustion phase parameter, and the precombustion chamber injection advance angle and fuel quantity of the next working cycle are automatically corrected based on the characteristic value of the combustion pressure of the last working cycle; When it is detected that the combustion center position of the last cycle is later than the target value, the precombustion chamber injection advance angle is increased by 5-10 degrees of crank angle, or the hydrogen injection quantity is increased by 5%-15%; when it is detected that the combustion center position is earlier than the target value or an explosion trend is detected, the precombustion chamber injection advance angle is decreased by 5-10 degrees of crank angle, or the injection quantity is decreased by 5%-15%.

7. An engine system comprising at least one cylinder, a piston, a main combustion chamber, a pre-chamber in communication with the main combustion chamber, a spark plug and a hydrogen fuel injector disposed within the pre-chamber, characterized by, The engine system further comprises an electronic control unit and a sensor assembly, the electronic control unit is used to execute the hydrogen internal combustion engine injection control method in any one of claims 1 to 6, and the sensor assembly comprises an in-cylinder pressure detection element and an explosion detection element, and the sensor assembly is arranged to feed signals to the electronic control unit.

8. The engine system of claim 7, wherein, The precombustion chamber is communicated with the main combustion chamber through a plurality of radial jet holes, each jet hole has a diameter of 1-3 mm, the number of jet holes is 4-8, and the opening directions of the jet holes are towards different regions in the main combustion chamber.

9. The engine system of claim 7, wherein: The hydrogen fuel injector comprises a high-pressure hydrogen supply source and a direct injection nozzle, and the injection pressure is 5-15 MPa; The pre-chamber fuel injector adopts an electromagnetic control injector or a piezoelectric control injector; When the hydrogen supply mode of the main combustion chamber is manifold injection, a plurality of injection nozzles are arranged on the intake manifold. Alternatively, when the hydrogen supply mode of the main combustion chamber is direct injection, a direct injection nozzle is additionally arranged on the top of each cylinder.

10. The engine system of claim 7, wherein: The electronic control unit comprises an adaptive control algorithm module, and the algorithm comprises a long short-term memory neural network (LSTM) or a fuzzy control model, which is used for predicting and compensating for the response time difference of each sensor.

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