Control method and device for integrated pre-combustion chamber of hydrogen fuel internal combustion engine

Abstract

The invention discloses a control method and device for an integrated pre-combustion chamber of a hydrogen fuel internal combustion engine, and the method comprises the steps: obtaining operation parameters such as pressure, temperature, crankshaft phase and equivalence ratio through a sensing module arranged in the pre-combustion chamber, and combining with a water mist vaporization and dilution model; and on the basis of comprehensively considering the water mist evaporation time, the airflow transportation time and the current rotating speed of the engine, the injection advance angle and the injection amount are calculated. The control unit calculates an injection correction factor and drives a micro-mist injector located on the side wall of the pre-combustion chamber to accurately inject water mist with the particle size of about 5-20 microns according to the deviation between the predicted peak temperature and the target temperature in combination with the knocking risk and the ignition stability requirement, so that the water mist is basically vaporized before spark discharge; therefore, peak temperature fine adjustment, NOx emission suppression and knocking protection are achieved. According to the invention, a very small amount of superfine water mist is accurately jetted in CA at 3-5 degrees before ignition, and the temperature of the hydrogen flame is finely adjusted by utilizing the dual effects of water evaporation heat absorption and steam dilution, so that the emission of NOx is obviously reduced, the knocking is inhibited, and the ignition reliability is ensured at the same time.

Description

Technical Field

[0001] This invention relates to the technical field of engines, and in particular to a control method and device for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine. Background Technology

[0002] The pre-combustion chamber ignition system, by introducing the flame into the main combustion chamber first, can significantly improve combustion speed and thermal efficiency, and also extend the lean combustion boundary to λ>2.0 or higher, thereby achieving ultra-lean combustion and reducing combustion instability. Existing research shows that using active pre-combustion chamber technology in hydrogen fuel cell internal combustion engines can utilize a high-pressure hydrogen jet to form a flame that triggers rapid combustion of the air-fuel mixture in the main combustion chamber. The peak pressure rise rate is controllable, and combustion efficiency can be improved by 5–10%, reducing NO... x Emissions can be reduced by 20–50%.

[0003] On the other hand, injecting water or steam into the combustion chamber to utilize its high latent heat of vaporization and dilution effect to lower the combustion temperature has been widely proven to suppress NO. x An effective way to reduce NO is through direct or steam injection. x Emissions can be reduced by 40–70%, and the impact on combustion performance is minimal while suppressing knocking; especially when the water mist particle size is <20 μm, vaporization is faster and more uniform, and temperature control is more precise.

[0004] Patent GB2594165A (corresponding to US Patent US11047341B2) proposes an apparatus and method for injecting fluid (including water) into the cavity after combustion in the pre-combustion chamber, and using a pressure sensor signal to trigger the injection to achieve cooling and flushing effects. However, the injection timing of this scheme is in the later stage of combustion, and its mechanism of action is completely different from the "micro-water mist temperature adjustment before ignition" of this invention. At the same time, it does not limit the droplet size range, nor does it perform fine closed-loop control of timing and injection volume for the lean combustion characteristics of the hydrogen pre-combustion chamber.

[0005] Patent US6988492B2 invented a hydrogen and liquid fuel injection system. This invention patent provides an independent injection device for hydrogen and liquid fuel. It can inject water in the combustion chamber at different times to delay hydrogen combustion. However, the water injection position is at the main combustion chamber inlet. There is no dedicated atomizing nozzle design for the pre-combustion chamber. The injection particle size and timing are not finely controlled. Moreover, the entire system requires extensive modifications to engine components.

[0006] Patent US11828220B1 invented a multimodal hydrogen injection scheme that utilizes pre-combustion chamber jet ignition to optimize combustion under different loads. However, it focuses on the injection and multiple ignition of hydrogen and air mixtures, without involving any form of water or water-alcohol mixture injection or micro-atomization temperature control, nor does it have closed-loop water volume regulation based on dP / dθ and λ feedback.

[0007] The aforementioned existing technologies either focus on the hydrogen injection and ignition process in the hydrogen pre-combustion chamber, or implement water injection for cooling or temperature reduction in the later stage of combustion or in the intake duct, none of which maintain the original overall structure of the pre-combustion chamber unchanged. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a control method and device for an integrated pre-combustion chamber in a hydrogen fuel cell internal combustion engine. This method involves adding a dedicated water mist injector to the side wall to precisely inject ultrafine water mist at 3–5°C CA before ignition. Combined with closed-loop regulation using pre-combustion chamber pressure, temperature, and equivalence ratio sensors, real-time fine-tuning of peak temperature and NO₂ levels are achieved. x Effective emission suppression and active protection against knocking. This invention addresses this gap by proposing a comprehensive solution that is structurally simplified, easy to modify, and balances heat absorption and cooling, gas dilution, and ignition reliability. To achieve the above-mentioned objectives and other advantages of this invention, a control method for an integrated pre-combustion chamber in a hydrogen fuel cell internal combustion engine is provided, comprising: Obtain engine operating parameters and identify operating conditions based on the operating parameters; The target peak temperature is generated and the temperature difference is calculated based on the results of the operating condition identification. The temperature difference is used to determine whether cooling is needed. Then, the control system adjusts the spray volume and angle of the side-mounted micro water mist nozzles to automatically adjust the spray volume according to changes in working conditions, so as to balance the cooling effect and ignition stability. When it is determined that cooling is required, the control system calculates the required injection advance angle value based on the influencing factors; then, based on the required advance angle value and the temperature difference, the control system calculates the injection correction factor and the final injection pulse width target, and can then perform closed-loop regulation of the pressure through the feedback signal of the water pressure sensor.

[0009] Preferably, the operating parameters include the pre-combustion chamber pressure P. pc Temperature T pc Crankshaft phase θ crank The operating parameters, including the equivalence ratio (lambda), water pressure, and knock index, are entered into a buffer with timestamps and then aligned.

[0010] Preferably, the operating conditions include speed, load, and lambda range.

[0011] Preferably, generating the target peak temperature and calculating the temperature difference based on the results of the operating condition identification specifically involves: The peak temperature prediction model and the water mist vaporization and dilution model are called by the results of the operating condition identification, and then the predicted peak temperature, uncertainty and water mist vaporization and transport time are estimated. The control system generates a target peak temperature based on the predicted peak temperature, uncertainty, and estimated water mist vaporization and transport time, and calculates the temperature difference as input for subsequent advance angle and injection volume calculations.

[0012] Preferably, the need for cooling is determined by the temperature difference, and then the control system adjusts the spray volume and angle of the side-mounted micro-water mist nozzles to automatically adjust the spray volume according to changes in operating conditions, thus balancing cooling effect and ignition stability. Specifically: When the temperature difference calculated by the control system requires cooling, the control system combines the evaporation time and transport time output by the water mist vaporization and dilution model with the current engine speed to calculate the required injection advance angle value. Taking into account the advance angle requirement and the temperature difference, the control system calculates the injection correction factor and the final injection pulse width target; The system determines whether the injection pressure has been established and stabilized. If not, an alarm is triggered and the water circuit is shut off. Alternatively, if the injection pressure has been established and stabilized, the control system sends a PWM control signal to the solenoid metering valve and executes the injection. The system assesses whether the pressure and condensation risk are normal during operation. If the assessment is abnormal, an alarm is triggered and the water circuit is shut off. Alternatively, if the assessment is normal, the system enters the injection and ignition standby phase.

[0013] Preferably, when the engine enters the target operating condition, the control system makes a comprehensive judgment on whether water spraying is needed for cooling and checks the current load and temperature conditions; if the load is low or the temperature is low, the water spraying is reduced or turned off to avoid excessive dilution even if the temperature difference is >0.

[0014] Preferably, a device for an integrated pre-combustion chamber for a hydrogen fuel cell internal combustion engine includes: The parameter acquisition module is used to acquire operating parameters in real time. The calculation module is used to calculate the target peak temperature and temperature difference; The control module is used to determine whether cooling is needed based on the temperature difference, and then to control the spray volume and angle of the side-mounted micro water mist nozzles through the control system, so as to automatically adjust the spray volume according to the changes in working conditions to balance the cooling effect and ignition stability.

[0015] Preferably, this invention acquires operating parameters such as pressure, temperature, crankshaft phase, and equivalence ratio through a sensing module arranged in the pre-combustion chamber. Combined with a water mist vaporization and dilution model, and taking into account water mist evaporation time, airflow transport time, and the current engine speed, it calculates the injection advance angle and injection quantity. The advance angle is preferably 3–5°CA within the engineering range and can be adjusted appropriately according to different operating conditions and calibration results. The control unit calculates the injection correction factor based on the deviation between the predicted peak temperature and the target temperature, combined with knock risk and ignition stability requirements. It then drives a micro-mist injector located on the side wall of the pre-combustion chamber to precisely inject water mist with a particle size of approximately 5–20 μm, ensuring that it is essentially vaporized before spark discharge, thereby achieving peak temperature fine-tuning and NO reduction. x Emission suppression and knock protection. Under low load or low temperature conditions, the system can automatically reduce or shut off injection to ensure ignition reliability.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are: 1) Without changing the structure of the hydrogen injector and spark plug, the peak temperature of the pre-combustion chamber can be precisely controlled by side injection.

[0017] 2) Employing micro-fine water mist injection before ignition effectively reduces NO. x It reduces emissions and increases knock margin.

[0018] 3) By introducing a closed-loop control strategy, the injection quantity can be automatically adjusted according to changes in operating conditions to balance cooling effect and ignition stability. Attached Figure Description

[0019] Figure 1 A schematic diagram of the pre-combustion chamber structure with a water mist temperature control device, according to the control method and apparatus for the integrated pre-combustion chamber of a hydrogen fuel internal combustion engine of the present invention. Figure 2 A schematic diagram of the water mist-hydrogen injection dual-loop control system for the control method and apparatus of the integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine according to the present invention. Figure 3 A flowchart of data acquisition and peak temperature prediction for the control method and apparatus of the integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine according to the present invention; Figure 4 A flowchart of the actuator and closed-loop control of the control method and device for the integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine according to the present invention; Figure 5 A flowchart illustrating the working process of the control method and apparatus for the integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine according to the present invention. Detailed Embodiments The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figure 1 A pre-combustion chamber device with a water mist temperature control device, comprising: The spark plug structure 2 includes a pre-combustion chamber shell 4. A hydrogen injector 1 is inserted into the upper end of the spark plug structure 2, and a pre-combustion chamber 3 is disposed in the lower part of the spark plug structure 2. The pre-combustion chamber 3 is connected to a side-mounted micro-water mist nozzle 5. The hydrogen injector 1 and the spark plug 2 are placed inside the shell 4 using the existing installation interface. The pre-combustion chamber 3 is connected to the main combustion chamber through a spray hole. The side-mounted micro-water mist nozzle 5 extends radially from the side wall of the shell 4, and the spray direction is directed towards the spark gap and the intersection area of ​​the hydrogen jets to ensure that the water mist covers the ignition core area before spark discharge, and the droplet size of the side-mounted micro-water mist nozzle 5 is controlled within 5–20 μm.

[0021] Furthermore, such as Figure 2 As shown, a water mist-hydrogen injection dual-loop control system includes: a control module, which is signal-connected to an on-board control unit, a hydrogen injection solenoid valve, a metering pump, and an electromagnetic metering valve; the on-board control unit is signal-connected to the electromagnetic metering valve and the hydrogen injection solenoid valve; the hydrogen injection solenoid valve is signal-connected to a hydrogen injector 1, which is connected to a pre-combustion chamber 3; the metering pump is signal-connected to the electromagnetic metering valve, which is signal-connected to a side-mounted micro-water mist nozzle 5, which is connected to the pre-combustion chamber 3.

[0022] The hydrogen injection solenoid valve is connected to a pressure reducing valve, the pressure reducing valve is connected to a hydrogen shut-off valve, and the hydrogen shut-off valve is connected to a hydrogen supply system.

[0023] The metering pump is connected to a water circuit shut-off valve, which in turn is connected to a water supply system. In summary, the hydrogen supply system enters the hydrogen injection solenoid valve via the hydrogen shut-off valve and pressure reducing valve, which drives the hydrogen injector 1 to supply hydrogen to the pre-combustion chamber 3. The water supply system enters the metering pump via the water circuit shut-off valve, with the pump outlet connected to the solenoid metering valve, and downstream connected to the side-mounted micro-water mist nozzle 5. The vehicle control unit (ECU) and control module are positioned at the top, respectively outputting control / regulation signals to the hydrogen injection solenoid valve and sending start / stop signals to the metering pump. The dashed lines represent electrical signals, and the solid lines represent the medium flow direction. Both nozzles point towards the pre-combustion chamber 3.

[0024] Furthermore, such as Figure 3 As shown, a control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine includes: Obtain engine operating parameters and perform operating condition identification based on these parameters, specifically: The system triggers parallel acquisition of operating parameters such as pre-combustion chamber pressure Ppc, temperature Tpc, crankshaft phase θcrank, equivalence ratio lambda, water circuit pressure, and knock index using a fixed crankshaft angle or time reference. The collected runtime parameters are buffered and aligned with timestamps; Operating conditions are identified based on operating parameters, including speed, load, and lambda range. Based on the results of operating condition identification, the peak temperature prediction model and the water mist vaporization and dilution model are invoked. These models are then used to predict peak temperature, uncertainty, output evaporation time, and transportation time. The peak temperature prediction model can be any type or combination of a mapping model, thermodynamic model, or adaptive prediction model; the specific modeling method is not limited. The water mist vaporization and dilution model can be established based on existing general droplet evaporation and heat and mass transfer calculation methods, such as using D... 2 The law of evaporation and the corresponding heat transfer and diffusion relationships have inputs including droplet diameter, temperature, pressure, local airflow velocity, etc., and outputs including the time required for droplet vaporization and dilution ratio. The specific model form and parameter sources can be determined through experiments, simulations or published literature, and are not limited.

[0025] The control system predicts the peak temperature T. pred Uncertainty U pred The target peak temperature T is generated from the estimated values ​​of water mist vaporization and transport time. target And calculate the temperature difference δ T As input for subsequent advance angle and injection volume calculations.

[0026] The temperature difference is used to determine whether cooling is needed. The control system then adjusts the spray volume and angle of the side-mounted micro water mist nozzles to automatically adjust the spray volume according to changes in operating conditions, thus balancing cooling effect and ignition stability.

[0027] Furthermore, such as Figure 4 As shown, the temperature difference is used to determine whether cooling is needed. The control system then adjusts the spray volume and angle of the side-mounted micro-water mist nozzles to automatically adjust the spray volume according to changes in operating conditions, balancing cooling effect and ignition stability. Specifically, this includes: For temperature difference δ T The system determines whether the temperature difference δ is greater than 0. T When the temperature difference δ is less than 0, dry ignition is maintained and the current control cycle ends. TWhen the value is greater than 0, the control system calculates the advance angle requirement value by combining the evaporation time, transportation time and engine angular velocity. The advance angle is 3–5°CA in the preferred range of engineering and can be adjusted within the allowable range according to the working conditions and calibration results. The control system has a comprehensive temperature difference δ T Calculate the injection correction factor to generate the final lead angle and pulse width target; Further determine whether the injection pressure has been established and is stable. If it is determined that the injection pressure has not been established and is unstable, an alarm will be triggered and the water circuit will be shut off. When it is determined that the injection pressure has been established and is stable, a PWM control signal is sent to the solenoid metering valve and injection is executed; The system further assesses whether the pressure and condensation risk are normal during operation. If the pressure and condensation risk are abnormal, an alarm is triggered and the water circuit is shut off. If the pressure and condensation risk are normal, the system enters the injection and ignition standby phase. The control system sends a pre-charge pressure build-up command to the metering pump and uses feedback signals from the water circuit pressure sensor to perform closed-loop pressure regulation, ensuring that the water circuit pressure meets the set requirements at the start of injection. When the pressure is normal and there is no condensation risk, a PWM control signal is sent to the solenoid metering valve to execute injection. During operation, the system continuously monitors the pressure and condensation risk. If an abnormality is detected, the water circuit actuator is immediately shut off and the system reverts to dry ignition mode; if operation is normal, the system enters the injection and ignition standby state. The above closed-loop control can be implemented by hardware logic, software algorithms, or a combination of both, and is not limited to a specific actuator type.

[0028] Furthermore, such as Figure 5 As shown, once the engine enters the target operating condition, the control system comprehensively determines whether water injection is needed for cooling and checks the current load and temperature conditions; if the load is low or the temperature is low, the water injection is reduced or shut off, even if δ T >0 also avoids excessive dilution. Specifically: Determine δ T If the value is greater than 0 and the operating condition is stable, and the result is no, then the dry ignition mode is maintained for cyclic detection, repeating until the operating condition changes or the machine is shut down. If the result is yes, then the load and temperature conditions are checked, and further determination is made as to whether the load or temperature is low. If the load or temperature is low, then the water injection is reduced or turned off to avoid excessive dilution, repeating until the operating condition changes or the machine is shut down. If the load or temperature is not low, then the injection advance angle θ generated by the execution layer is used. injstart If the pulse width target is met, the metering pump is activated for pre-charging and pressure build-up, and the solenoid metering valve is opened to execute injection when the crankshaft rotates to the injection advance angle position. Injection continues until the set ignition timing θ is reached. ig At this time, the spark plug ignites the mixture, and the high-temperature flame generated in the pre-combustion chamber ignites the air-fuel mixture in the main combustion chamber through the nozzle. After ignition, the control system monitors the pre-combustion chamber pressure P in real time within a short monitoring window.pc The system monitors the pressure rise rate (dP / dθ) and knock and misfire indicators; it then checks for any detected anomalies. If no anomalies are detected, the current control parameters are maintained, and the cycle repeats until the operating conditions change or the machine is shut down. If an anomaly is detected, the PWM opening, injection pulse width, or the water spray retraction dry mode is turned off, and the cycle repeats until the operating conditions change or the machine is shut down.

[0029] In summary, this invention, while maintaining the original overall structure of the pre-combustion chamber, achieves real-time fine adjustment of peak temperature and NO by adding a dedicated water mist injector to the side wall to precisely spray ultrafine water mist 3–5°C before ignition, combined with closed-loop regulation of pre-combustion chamber pressure, temperature, and equivalence ratio sensors. x Effective emission suppression and active protection against knocking. This invention addresses this gap by proposing a comprehensive solution that is structurally simplified, easy to modify, and takes into account heat absorption and cooling, gas dilution, and ignition reliability.

[0030] The number of devices and processing scale described herein are for simplification of the invention. Applications, modifications, and variations of this invention will be readily apparent to those skilled in the art. Although embodiments of the invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine, characterized in that, include: Obtain engine operating parameters and identify operating conditions based on the operating parameters; The target peak temperature is generated and the temperature difference is calculated based on the results of the operating condition identification. The temperature difference is used to determine whether cooling is needed. Then, the control system adjusts the spray volume and angle of the side-mounted micro water mist nozzles to automatically adjust the spray volume according to changes in working conditions, so as to balance the cooling effect and ignition stability. When it is determined that cooling is required, the control system calculates the required injection advance angle value based on the influencing factors; then, based on the required advance angle value and the temperature difference, the control system calculates the injection correction factor and the final injection pulse width target, and can then perform closed-loop regulation of the pressure through the feedback signal of the water pressure sensor.

2. The control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine as described in claim 1, characterized in that, The operating parameters include the pre-combustion chamber pressure P. pc Temperature T pc Crankshaft phase θ crank The operating parameters, including the equivalence ratio (lambda), water pressure, and knock index, are entered into a buffer with timestamps and then aligned.

3. The control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine as described in claim 1, characterized in that, The operating conditions include speed, load, and lambda range.

4. The control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine as described in claim 1, characterized in that, The specific steps for generating the target peak temperature and calculating the temperature difference based on the results of the aforementioned operating condition identification are as follows: The peak temperature prediction model and the water mist vaporization and dilution model are called by the results of the operating condition identification, and then the predicted peak temperature, uncertainty and water mist vaporization and transport time are estimated. The control system generates a target peak temperature based on the predicted peak temperature, uncertainty, and estimated water mist vaporization and transport time, and calculates the temperature difference as input for subsequent advance angle and injection volume calculations.

5. The control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine as described in claim 4, characterized in that, The temperature difference is used to determine whether cooling is needed. The control system then adjusts the spray volume and angle of the side-mounted micro-water mist nozzles to automatically adjust the spray volume according to changes in operating conditions, balancing cooling effectiveness and ignition stability. Specifically: When the temperature difference calculated by the control system requires cooling, the control system combines the evaporation time and transport time output by the water mist vaporization and dilution model with the current engine speed to calculate the required injection advance angle value. Taking into account the advance angle requirement and the temperature difference, the control system calculates the injection correction factor and the final injection pulse width target; The system determines whether the injection pressure has been established and stabilized. If not, an alarm is triggered and the water circuit is shut off. Alternatively, if the injection pressure has been established and stabilized, the control system sends a PWM control signal to the solenoid metering valve and executes the injection. The system assesses whether the pressure and condensation risk are normal during operation. If the assessment is abnormal, an alarm is triggered and the water circuit is shut off. Alternatively, if the assessment is normal, the system enters the injection and ignition standby phase.

6. The control method for an integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine as described in claim 1, characterized in that, It also includes the control system making a comprehensive judgment on whether water spraying is needed to cool the engine when it enters the target operating condition, and checking the current load and temperature conditions; if the load is low or the temperature is low, the water spraying is reduced or turned off, and excessive dilution is avoided even if the temperature difference is >0.

7. A device for an integrated pre-combustion chamber for a hydrogen fuel cell internal combustion engine, characterized in that, The control method for the integrated pre-combustion chamber of a hydrogen fuel cell internal combustion engine, as described in any one of claims 1-6, specifically includes: The parameter acquisition module is used to acquire operating parameters in real time. The calculation module is used to calculate the target peak temperature and temperature difference; The control module is used to determine whether cooling is needed based on the temperature difference, and then to control the spray volume and angle of the side-mounted micro water mist nozzles through the control system, so as to automatically adjust the spray volume according to the changes in working conditions to balance the cooling effect and ignition stability.

8. An electronic device, characterized in that, The electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the control method for the integrated pre-combustion chamber of the hydrogen fuel cell internal combustion engine according to any one of claims 1-6.

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