Constant-speed load self-adaption method for hydrogen internal combustion engine without throttle valve control and application of constant-speed load self-adaption method

Abstract

The invention discloses a hydrogen internal combustion engine constant speed load self-adaption method without throttle valve control and application, and belongs to the technical field of spark ignition type hydrogen internal combustion engine control. The invention discloses a constant-speed load self-adaption method for a hydrogen internal combustion engine without throttle valve control. The method comprises the following steps that throttle valve opening degree setting is conducted on the starting working condition, the warming-up working condition and the power output working condition of the hydrogen internal combustion engine; performing constant-speed operation control on a warm-up working condition; and carrying out constant-speed load self-adaptive control on a power output working condition. By the adoption of the hydrogen internal combustion engine constant-speed load self-adaption method without throttle valve control and the application, constant-speed operation and load self-adaption of the hydrogen internal combustion engine without depending on throttle valve adjustment are achieved, and air inflow control of the hydrogen internal combustion engine in the starting, warming-up and power output states better meets the working condition requirement; the hydrogen internal combustion engine is faster in response to the real-time change of the load and more stable in rotating speed.

Description

Technical Field

[0001] The present invention relates to the technical field of control of spark-ignition hydrogen internal combustion engines, and in particular to a constant speed load self-adaptive method for hydrogen internal combustion engines separated from throttle control and its application. Background Art

[0002] Hydrogen is a clean fuel with zero carbon emissions, making it an ideal "green" fuel. In the future industrial power sector, the development of hydrogen internal combustion engines has an important strategic position.

[0003] Due to the unique physical properties of hydrogen, its combustion characteristics are significantly different from those of traditional internal combustion engines. Unlike the ignition method of traditional diesel engines, hydrogen has a high auto-ignition temperature, making compression ignition difficult to achieve. The ignition method of hydrogen internal combustion engines is mainly spark ignition. Unlike traditional gasoline and natural gas internal combustion engines, which are limited by the three-way catalytic converter and can only burn near the chemical equivalence ratio, hydrogen has a wide flammability range and the pollutant emissions generated are mainly nitrogen oxides. Therefore, the concentration of the mixture in the cylinder of a hydrogen internal combustion engine can vary over a wide range, and when the mixture is burned at a relatively lean concentration, the emission level of nitrogen oxides can be effectively reduced, and even zero nitrogen oxide emissions can be achieved. Therefore, based on the unique combustion characteristics of hydrogen internal combustion engines, their control methods are also significantly different from those of traditional internal combustion engines.

[0004] On the one hand, due to the characteristics of spark-ignition internal combustion engines, the intake air volume of spark-ignition hydrogen internal combustion engines must be controlled through the throttle to adjust the mixture concentration in the cylinder according to the operating conditions. This is especially true during startup and under low-load conditions. To ensure stable startup and combustion stability under low-load conditions, throttle control of the intake air volume is essential to maintain an appropriate mixture concentration. On the other hand, due to hydrogen's wide flammability range and emission advantages under lean-burn conditions, the throttle opening can be maintained at a wide or even fully open position under medium- and high-load conditions. Therefore, when hydrogen internal combustion engines need to operate under constant speed and load adaptive conditions, control methods developed for existing compression-ignition diesel engines or spark-ignition gasoline and natural gas internal combustion engines are not applicable. This is because compression-ignition diesel engine control methods do not include throttle control, while spark-ignition gasoline and natural gas internal combustion engines rely primarily on feedback from exhaust gas oxygen sensors and throttle control to achieve constant speed operation.

[0005] To achieve adaptive control of hydrogen internal combustion engines at constant speed and load, new control methods are essential for their application. For example, hydrogen internal combustion engines can generate electricity at a constant frequency, converting hydrogen energy into high-quality electricity. This electricity can then be transported across regions via the power grid, indirectly resolving the storage and transportation difficulties associated with hydrogen's low density. This, in turn, promotes the widespread use of hydrogen energy and reduces carbon emissions. Summary of the Invention

[0006] The purpose of the present invention is to provide a method and application for constant speed and load adaptation of a hydrogen internal combustion engine without throttle control, so as to realize constant speed operation and load adaptation of the hydrogen internal combustion engine without relying on throttle adjustment, so that the intake volume control of the hydrogen internal combustion engine during startup, warm-up and power output states is more in line with the working conditions; the hydrogen internal combustion engine responds faster to real-time changes in load and has a more stable speed.

[0007] To achieve the above object, the present invention provides a method for self-adapting a constant speed load of a hydrogen internal combustion engine without throttle control, comprising the following steps:

[0008] S1. Setting the throttle opening for the hydrogen internal combustion engine under starting condition, warm-up condition, and power output condition respectively.

[0009] Because the combustion characteristics of hydrogen internal combustion engines differ from those of traditional compression-ignition diesel engines and other internal combustion engines, such as gasoline and natural gas spark-ignition engines, achieving constant speed and load-adaptive control cannot be completely separated from, nor can it be completely reliant on, throttle control. Instead, the throttle opening must be fixed at a certain level to control the air intake of the hydrogen internal combustion engine according to different operating conditions. Specifically, during hydrogen engine startup, the throttle opening must be kept small to ensure a smooth start. During warm-up, the throttle opening is kept small to medium to control the lean burn rate, minimize cyclic variation, and ensure stable operation and rapid warm-up. During power output, the throttle opening is kept wide open to increase the air intake, allowing the hydrogen internal combustion engine to operate with a lean fuel mixture as much as possible, thereby reducing the formation and emission of nitrogen oxides.

[0010] Preferably, a fixed throttle opening is maintained under starting conditions, warm-up conditions and constant speed power output conditions.

[0011] Preferably, the throttle opening is 5%-8% under the starting condition, 10%-15% under the warm-up condition, and 15%-100% under the power output condition.

[0012] Preferably, under the power output operating condition, when the hydrogen internal combustion engine is running at a target speed of 25%-40% of the maximum speed, the throttle opening is 15%-20%; when the hydrogen internal combustion engine is running at a target speed of 40%-50% of the maximum speed, the throttle opening is 20%-25%; when the hydrogen internal combustion engine is running at a target speed of more than 50% of the maximum speed, the throttle opening is 100%.

[0013] Under the above-mentioned warm-up condition and power output condition, the corresponding fixed throttle opening is maintained, and the hydrogen internal combustion engine is controlled to operate at a constant speed and to adapt to the load.

[0014] S2. Constant speed operation control in warm-up condition.

[0015] To ensure good lubrication between the various friction pairs during operation, thereby reducing mechanical wear, extending the engine's service life, and improving its reliability, the engine oil must be maintained within a certain temperature range before the engine enters power output mode. Therefore, a warm-up period is required between startup and power output. Furthermore, to ensure stable operation and a relatively stable noise level during the warm-up period, the engine is controlled to operate at a constant speed.

[0016] Unlike traditional spark-ignition gasoline and natural gas internal combustion engines, which achieve constant speed control by adjusting the throttle opening and fuel injection pulse width based on feedback from exhaust oxygen sensors, hydrogen internal combustion engines maintain a fixed throttle opening during warm-up. Therefore, speed feedback adjustment is required through the acquisition of other physical quantities to achieve constant speed control.

[0017] Preferably, in S2, the constant speed operation control in the warm-up condition includes the following steps:

[0018] S21. Under the calibrated basic warm-up MAP and warm-up throttle opening, the hydrogen internal combustion engine operates at an actual speed, where the actual speed is 80%-120% of the target speed;

[0019] S22, obtaining a PID control adjustment amount of an operating parameter based on the speed difference between the actual speed and the target speed;

[0020] S23, obtaining MAP execution parameters based on the current actual speed and oil temperature of the hydrogen internal combustion engine and data in the calibrated basic warm-up MAP;

[0021] S24, adding the PID control adjustment amount and the MAP execution parameter to obtain the actual operating parameters of the hydrogen internal combustion engine, and obtaining a new actual speed;

[0022] S25. Repeat S22-S24, the actual speed converges to the target speed, and the hydrogen internal combustion engine maintains stable operation at the target speed until the warm-up process is completed.

[0023] Preferably, in S21, the actual speed and oil temperature are used as independent variables to calibrate the basic warm-up MAP, and the parameter data of the calibrated basic warm-up MAP include hydrogen injection pulse width, ignition advance angle and hydrogen injection start time.

[0024] The parameters of MAP are expressed as:

[0025] y=f(n,T)

[0026] Where y represents the hydrogen injection pulse width, ignition advance angle, or the start time of hydrogen injection; n represents the actual operating speed of the hydrogen internal combustion engine; and T represents the engine oil temperature. The MAP calibration variable T replaces the throttle opening in traditional spark-ignition internal combustion engine constant speed control, eliminating the influence of this key control parameter on the warm-up MAP data.

[0027] In S23, the hydrogen injection pulse width, ignition advance angle, and hydrogen injection timing at different speeds and oil temperatures in the MAP data are obtained during the calibration process of the hydrogen internal combustion engine. Since only discrete values of the speed and oil temperature can be obtained during the calibration process, when the actual speed and oil temperature are values at non-calibrated points, the MAP execution parameters are determined by performing two-dimensional linear interpolation using the data from the nearest calibration point.

[0028] By querying the basic warm-up MAP, the speed is roughly feedback-adjusted; by using the PID control adjustment amount, fine feedback adjustment is performed; the two work together to make the hydrogen internal combustion engine speed converge quickly to the warm-up target speed.

[0029] S3. Constant speed load adaptive control of power output condition.

[0030] Similar to the control of constant speed operation in the warm-up condition, constant speed operation and load adaptive control in the power output condition also require feedback adjustment of the speed through other physical quantities.

[0031] Preferably, in S3, the constant speed load adaptive control of the power output working condition includes the following steps:

[0032] S31, determining a power output throttle opening according to a target speed of the hydrogen internal combustion engine;

[0033] S32. Under the calibrated basic operating MAP and power output throttle opening, the hydrogen internal combustion engine operates at an actual speed, where the actual speed is 80%-120% of the target speed;

[0034] S33, reading the transient speed several times, and averaging the transient speed results read several times to obtain an average actual speed;

[0035] S34, obtaining a PID control adjustment amount of the operating parameter by averaging the speed difference between the actual speed and the target speed;

[0036] S35. Combining the calibrated basic operating MAP, the average actual speed, and the load variable to obtain MAP execution parameters in the calibrated basic operating MAP;

[0037] S36, adding the MAP execution parameter and the PID control adjustment amount to obtain the actual operating parameter of the hydrogen internal combustion engine, and obtaining a new actual speed;

[0038] S37. Repeat S33-S36, the actual speed converges to the target speed, and the hydrogen internal combustion engine maintains stable operation at the target speed.

[0039] Preferably, in said S32, the actual speed and the load variable are used as independent variables to calibrate the basic working MAP.

[0040] The basic working MAP data includes hydrogen injection pulse width, ignition advance angle and hydrogen injection start time. All three are discrete functions of speed and load, expressed as:

[0041] y1=f1(n,load)

[0042] Among them, y1 represents the hydrogen injection pulse width, ignition advance angle or hydrogen injection start time, n represents the speed of the hydrogen internal combustion engine, and load is a dummy variable.

[0043] In the above S35, the hydrogen injection pulse width, ignition advance angle and hydrogen injection timing at different speeds and loads in the MAP data are obtained during the calibration process of the hydrogen internal combustion engine. Since only discrete values of speed and load can be taken during the calibration process, when the actual speed and load variables are values of non-calibrated points, the MAP execution parameters are determined by performing two-dimensional linear interpolation using the data of the nearest calibration point.

[0044] When a hydrogen internal combustion engine's load changes, it causes changes in engine speed, causing the queried MAP execution parameters to deviate significantly from those before the load change. This accelerates rapid load adaptation and quickly achieves speed stabilization. Similarly, querying the basic operating MAP allows for rough feedback adjustment of the speed, which allows for rapid changes in the engine's load. Fine feedback adjustment is achieved through PID control, and the two work together to quickly converge the engine's speed toward the power output target speed.

[0045] In the warm-up condition, the hydrogen internal combustion engine only needs to overcome its own friction work and the work consumed by other accessories, and does not output power to the outside. Its load is basically stable, so the injection pressure of the nozzle remains basically unchanged under this condition. As for the power output condition, since the hydrogen internal combustion engine needs to face variable load conditions and the demand for hydrogen is different, the injection pressure fluctuation range of the hydrogen nozzle during the load change process is much larger than the fluctuation range in the warm-up working state. Therefore, in order to reduce the impact of rail pressure changes on the constant speed operation and load adaptation of the hydrogen internal combustion engine, the load parameter considers the impact of speed difference and rail pressure deviation (i.e., injection pressure deviation) at the same time. In addition, in order to eliminate the impact of high transient speed of the hydrogen internal combustion engine on the control, the specific method is to take the average of the transient speed of the hydrogen internal combustion engine read multiple times, and then calculate the speed deviation with the target speed.

[0046] Preferably, the load variable is a function of the speed difference between the average actual speed and the target speed, and the rail pressure difference between the actual rail pressure and the calibrated rail pressure, and is expressed as:

[0047] load=z(diff_a_n,diff_p)

[0048] Wherein, load represents the load of the hydrogen internal combustion engine during power generation, diff_a_n represents the speed difference between the average speed and the target speed, and diff_p represents the difference between the calibrated rail pressure and the actual rail pressure.

[0049] The load data is obtained during the hydrogen internal combustion engine calibration process. Since only discrete values of speed and rail pressure deviation can be obtained during the calibration process, when the values of diff_a_n and diff_p are values of non-calibrated points, the load variable value is determined by two-dimensional linear interpolation using the data of the nearest calibration point.

[0050] By averaging the speed, the influence of instantaneous speed reading on constant speed operation control is eliminated; by introducing the virtual variable load, not only the influence of the throttle on the calibration of the basic working MAP is eliminated, so that the throttle can always be kept fully open or in a certain state during power output conditions, but also the influence of the difference between the actual injection pressure and the injection pressure used during calibration on constant speed control is reduced; at the same time, the use of the virtual variable load makes the basic working MAP calibration of the hydrogen internal combustion engine under different load conditions more accurate, makes the MAP execution parameters closer to the target speed and target load requirements, and improves the accuracy of rough feedback adjustment; finally, through the joint adjustment of more accurate MPA execution parameters and PID control adjustment amount, the hydrogen internal combustion engine always maintains a constant speed during load changes, ensuring its tolerance and dynamic response to load changes.

[0051] The above-mentioned constant speed load self-adaptive method of a hydrogen internal combustion engine without throttle control is applied in the constant frequency power generation and propeller driving of a hydrogen internal combustion engine.

[0052] The advantages and positive effects of the method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control and its application described in the present invention are: in combination with the working characteristics of the hydrogen internal combustion engine, the throttle, a key control parameter in the spark-ignition internal combustion engine, is separated from the load of the hydrogen internal combustion engine during control, so that the intake volume control of the hydrogen internal combustion engine during startup, warm-up and power output states is more in line with the working conditions; by introducing the virtual control parameter load, the relationship between the basic working MAP of the hydrogen internal combustion engine and different loads is made more precise, and the response to changes in the load of the hydrogen internal combustion engine is more accurate; by simultaneously feeding back and correcting the actual execution parameters in real time through load and PID control adjustment amounts, the hydrogen internal combustion engine responds faster to real-time changes in load and makes the speed more stable.

[0053] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a control principle diagram of an embodiment of the present invention;

[0055] Figure 2 This is a flow chart of independent throttle control according to an embodiment of the present invention;

[0056] Figure 3 This is a flow chart of warm-up condition control according to an embodiment of the present invention;

[0057] Figure 4 This is a flow chart of power output working condition control according to an embodiment of the present invention;

[0058] Figure 5 This is a flow chart of power output load calculation according to an embodiment of the present invention;

[0059] Figure 6 This is a diagram of the propeller speed and power and the corresponding hydrogen internal combustion engine speed and output power in Example 1 of the present invention. DETAILED DESCRIPTION

[0060] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. In the event of any inconsistency, the meaning described in this specification or the meaning derived from the contents recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application. In order to accurately describe the technical content in this application and to accurately understand the present invention, the following explanations or definitions are given for the terms used in this specification before describing the specific embodiments:

[0061] 1) Hydrogen internal combustion engine: This refers to an internal combustion engine that uses hydrogen as fuel. The combustion of a mixture of hydrogen and air drives the reciprocating motion of the piston, which pushes the connecting rod, which in turn rotates the crankshaft, generating rotational power. This differs from a hydrogen fuel cell, which is a power generation device that directly converts the chemical energy of hydrogen and oxygen into electrical energy.

[0062] 2) Transient speed of hydrogen internal combustion engine: It is the crankshaft speed of the hydrogen internal combustion engine collected multiple times in one working cycle. The instantaneous speed is lower during the intervals between cylinders working and higher when each cylinder is working. It varies within a certain range within the same cycle, and the size of the variation range is related to the number of cylinders in the hydrogen internal combustion engine.

[0063] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0064] Example 1

[0065] Based on a 2.0L hydrogen internal combustion engine used to drive the propeller, constant speed operation and load adaptive control of the hydrogen internal combustion engine are achieved. The hydrogen internal combustion engine and propeller are mechanically connected through a transmission with a transmission ratio of 2.0, and the hydrogen internal combustion engine speed range is 0-6000r / min.

[0066] like Figure 1 As shown, a constant speed load adaptive control method for a hydrogen internal combustion engine without throttle control is used to control the hydrogen internal combustion engine to drive a propeller to provide power, comprising the following steps:

[0067] First, the throttle opening of the hydrogen internal combustion engine is independently controlled, such as Figure 2 As shown. In the starting condition, in order to ensure the stable starting of the hydrogen internal combustion engine, a smaller throttle opening of 8% is selected. In the warm-up condition, combined with Figure 6 The propeller speed characteristics shown here select a lower propeller speed for warm-up to reduce load and save fuel. A propeller speed of 600 rpm is selected for the warm-up condition, corresponding to a hydrogen internal combustion engine speed of 1200 rpm. To achieve stable combustion and rapid warm-up during this condition, a small to medium throttle opening of 12% is selected. This ensures a small intake volume and a rich in-cylinder mixture, minimizing combustion cycle variability and reducing the amount of heat required to heat excess air, accelerating oil temperature rise. Under power output conditions, the propeller speed ranges from 750 rpm to 2450 rpm, corresponding to a hydrogen internal combustion engine speed range of 1500 rpm to 4900 rpm. Under the constraints of combustion stability and reduction of nitrogen oxide emissions, the throttle opening is 15%-20% in the stable lean-burn condition when the speed is in the range of 1500r / min-2500r / min; the throttle opening is 20%-25% in the range of 2500r / min-3000r / min; when the speed is higher than 3000r / min, the throttle opening is 100%.

[0068] Then, the constant speed operation control of the hydrogen internal combustion engine in the warm-up condition is carried out, such as Figure 3 The warm-up target speed is 1200 rpm. Maintaining a 12% throttle opening, the calibrated base warm-up MAP is shown in Table 1. The top row indicates the speed, which is near the warm-up target speed, ranging from 1050 rpm to 1350 rpm in 10 rpm increments. The leftmost column indicates the oil temperature (T), ranging from -20°C to 90°C in 5°C increments.

[0069] Table 1 Schematic diagram of calibration contents of basic warm-up MAP

[0070]

[0071] The specific control method is as follows: Maintaining a throttle opening of 12%, the MAP execution parameters are obtained by performing two-dimensional linear interpolation on the base warm-up MAP using the real-time engine speed n and oil temperature T. Rough control parameters, including hydrogen injection pulse width, ignition advance angle, and injection timing, are obtained from the calibrated MAP. PID control calculations are performed based on the speed difference between the real-time speed n and the warm-up target speed of 1200 r / min, resulting in fine PID control adjustments for hydrogen injection pulse width, ignition advance angle, and injection timing. The actual control parameters are then added to the MAP execution parameters to control the hydrogen engine speed to converge toward the warm-up target speed of 1200 r / min and maintain stability until the warm-up process is complete.

[0072] Finally, the constant speed load adaptive control of the hydrogen internal combustion engine under power output condition is carried out, such as Figure 4 The speed range of hydrogen internal combustion engine in power output condition is 1500r / min-4900r / min. Figure 6 The propeller speed characteristics shown in the figure correspond to the required power and speed of the hydrogen internal combustion engine. When the propeller is operating in a certain state, the hydrogen internal combustion engine is required to operate stably at a certain speed and achieve the corresponding power output, which is called load adaptation in the constant speed operation state. The throttle state for power output conditions is described in the section on independent throttle control. As shown in Table 2, the top row indicates the speed, ranging from 1400 rpm to 5000 rpm in 100 rpm steps; the leftmost column represents the dummy variable load, ranging from 0% to 100% in 10% steps.

[0073] Table 2 Basic work of calibration MAP calibration content diagram

[0074]

[0075] The calculation method of the virtual variable load is as follows Figure 5 As shown. It is determined by speed deviation and rail pressure deviation, and its calibration table is shown in Table 3. Based on the reference speed and reference rail pressure (injection pressure), the load variable is calibrated with speed deviation and rail pressure deviation reaching ±50% as the calibration boundaries. The injection pressure is 100 bar in the calibrated state. When the load of the hydrogen internal combustion engine changes with the operating requirements of the propeller, the hydrogen consumption rate fluctuates, causing fluctuations in the hydrogen injection pressure. Since the hydrogen flow rate of the hydrogen nozzle is strongly correlated with the injection pressure, fluctuations in the injection pressure can easily cause changes in the hydrogen injection amount, resulting in large speed fluctuations. The load variable actively eliminates this effect.

[0076] Table 3 Schematic diagram of virtual variable load calibration content

[0077]

[0078] The specific control method is as follows: The propeller power demand derives the corresponding propeller speed, thereby determining the corresponding target speed and output power of the hydrogen internal combustion engine. The throttle state is determined based on the target engine speed. A specific engine speed is determined by combining it with the basic operating map. To eliminate the influence of the hydrogen internal combustion engine's instantaneous speed on constant speed control, the engine speed is averaged. Specifically, 50 instantaneous speed averages (M = 50) are taken to obtain the average speed a_n. Two-dimensional linear interpolation is performed on the average speed a_n and the load value within the calibrated basic operating map to obtain the MAP execution parameters, which are used to make a rough correction to the speed over a large range. The speed difference between the average speed a_n and the hydrogen internal combustion engine's target speed is calculated to obtain the PID control adjustment variable. The PID adjustment parameters are then determined to make a fine correction to the speed over a small range. Finally, the actual execution parameters are obtained by adding the MAP execution parameters and the PID control adjustment variable to control the hydrogen internal combustion engine's speed to converge toward the power output target speed and maintain stability.

[0079] When the propeller is required to maintain a constant power output, such as when propulsing a ship or aircraft at a constant speed, the propeller's operating characteristics dictate a one-to-one correspondence between output power and speed. In this case, the hydrogen internal combustion engine is controlled to maintain constant power output as needed. When the propeller is required to output variable power, such as during acceleration or deceleration of a ship or aircraft, varying propeller power demands are issued, causing speed changes and, consequently, the target speed of the hydrogen internal combustion engine. This control method uses MAP interpolation to rapidly control the hydrogen internal combustion engine speed toward the target speed, while the PID control adjustment ensures rapid and stable convergence to the target speed, thus achieving load adaptation and constant speed operation control for the hydrogen internal combustion engine.

[0080] Through this control method, in the application of driving propellers, the load and throttle state of the hydrogen internal combustion engine are decoupled, so that the hydrogen internal combustion engine can output power stably as required under lean-burn conditions, and achieve constant speed operation and load adaptation.

[0081] Example 2

[0082] The control method of the present invention is implemented in combination with a 1.0L inline 4-cylinder naturally aspirated intake port injection hydrogen internal combustion engine generator set. The allowable speed range of the hydrogen internal combustion engine is 0-6000r / min, the target power generation frequency of the generator set is 50±0.2Hz, 50Hz corresponds to a power generation speed of 3000r / min, and the rated power generation power is 10kW.

[0083] like Figure 1 As shown, a constant speed load adaptive control method for a hydrogen internal combustion engine without throttle control is used to control the hydrogen internal combustion engine to drive a propeller to provide power, comprising the following steps:

[0084] First, the throttle opening of the hydrogen internal combustion engine is independently controlled, such as Figure 2 As shown. During startup, to ensure stable startup of the hydrogen internal combustion engine, a relatively small throttle opening of 8% is selected. During warm-up, a speed of 1500 rpm is selected as the warm-up condition. To achieve stable combustion and rapid warm-up during warm-up, a small to medium throttle opening of 15% is selected to ensure a small intake volume and a richer in-cylinder mixture, reducing combustion cycle variations, while also reducing the amount of heat required to heat excess air and accelerating the oil temperature rise process. During power output, the target speed for the hydrogen internal combustion engine's power output is fixed at 3000 rpm, controlled by the output AC power frequency requirements of the fixed-frequency generator set. The throttle opening is always maintained at 100%, controlling the in-cylinder mixture to a lean burn state and minimizing the generation and emission of nitrogen oxide pollutants.

[0085] Then, the constant speed operation control of the hydrogen internal combustion engine in the warm-up condition is carried out, such as Figure 3 The warm-up target speed is 1500 rpm. Maintaining a 15% throttle opening, the calibrated basic warm-up MAP is shown in Table 4. The top row indicates the speed, which is near the warm-up target speed, ranging from 1450 rpm to 1650 rpm in 10 rpm increments. The leftmost column indicates the oil temperature (T), which ranges from -20°C to 90°C in 5°C increments.

[0086] Table 4 Schematic diagram of calibration contents of basic warm-up MAP

[0087]

[0088] The specific control method is as follows: Maintaining a throttle opening of 15%, the engine's real-time speed n and oil temperature T are used to perform two-dimensional linear interpolation within the base warm-up MAP to obtain MAP execution parameters. Using the calibrated MAP, the coarse control parameters, including hydrogen injection pulse width, ignition advance angle, and injection timing, are obtained. PID control calculations are performed based on the speed deviation between the real-time speed n and the warm-up target speed of 1500 rpm to obtain fine PID control adjustments, including those for hydrogen injection pulse width, ignition advance angle, and injection timing. These two parameters are summed to obtain the actual execution control parameters, controlling the engine speed to converge toward the warm-up target speed of 1500 rpm and maintain stability until the warm-up process is complete.

[0089] Finally, the constant speed load adaptive control of the hydrogen internal combustion engine under power output condition is carried out, such as Figure 4The target speed for the hydrogen internal combustion engine under the power output condition is 3000 rpm, and the throttle is always kept at 100%. The calibrated base MAP is shown in Table 5. The top row represents the speed, ranging from 2850 rpm to 3150 rpm in 10 rpm steps. The leftmost column represents the dummy variable load, ranging from 0% to 100% in 5% steps.

[0090] Table 5 Basic work of calibration MAP calibration content diagram

[0091]

[0092] The calculation method of the virtual variable load is as follows Figure 5 As shown, it is determined by the speed deviation and rail pressure deviation, and its calibration table is shown in Table 6. Based on the reference speed and reference rail pressure (injection pressure), the load variable is calibrated with the speed deviation reaching ±10% and the rail pressure deviation reaching ±50% as the calibration boundaries. Among them, the reference speed is 3000r / min and the calibration rail pressure is 6bar. When the load demand of the hydrogen internal combustion engine fixed-frequency generator set changes, the hydrogen injection pressure fluctuates due to the change in hydrogen consumption rate. The hydrogen flow rate of the hydrogen nozzle is strongly correlated with the injection pressure. Therefore, fluctuations in the injection pressure can easily cause changes in the hydrogen injection amount, resulting in large speed fluctuations. The load variable calculation fully considers the rail pressure change, thereby eliminating this effect and improving the stability of the power generation frequency.

[0093] Table 6 Load variable calibration content diagram

[0094]

[0095] The specific control method is as follows: the throttle state is determined by the target speed of the hydrogen internal combustion engine, which is 3000 rpm, and the throttle state is maintained at 100%. A fixed engine speed is determined based on the basic operating map. To eliminate the influence of the hydrogen internal combustion engine's instantaneous speed on constant speed control, the engine speed is averaged. Specifically, 20 instantaneous speed averages (M = 20) are taken to obtain the average speed a_n. Two-dimensional linear interpolation is performed on the average speed a_n and the load value within the calibrated basic operating map to obtain the MAP execution parameters, which are used to make a rough correction to the speed over a large range. The speed deviation is calculated between the average speed a_n and the hydrogen internal combustion engine's target speed to obtain the PID control adjustment variable. The PID adjustment parameters are then determined to make a fine correction to the speed over a small range. Finally, the actual execution parameters are obtained by adding the MAP execution parameters and the PID control adjustment variable. The hydrogen internal combustion engine speed is controlled to converge to the power output target speed and maintain stability, achieving constant speed operation of the hydrogen internal combustion engine fixed-frequency generator set.

[0096] When the power supply load corresponding to the hydrogen internal combustion engine fixed-frequency generator set remains constant, under this control method, the unit maintains a constant speed and power generation power, and outputs a stable current; when the load demand for power generation power changes, it will cause a disturbance in the speed of the hydrogen internal combustion engine. Under this control method, the hydrogen internal combustion engine set responds quickly to this disturbance, so that the speed is always maintained at the target power generation speed of 3000r / min, ensuring the stability of the power generation frequency, and the power generation power is quickly adjusted to the power matching the load demand, realizing the self-adaptation of the power generation power of the hydrogen internal combustion engine set, that is, the self-adaptation of the hydrogen internal combustion engine load.

[0097] Through this control method, in the application of driving propellers, the load and throttle state of the hydrogen internal combustion engine are decoupled, so that the hydrogen internal combustion engine can output power stably as required under lean-burn conditions, and achieve constant speed operation and load adaptation.

[0098] Through this control method, in the application of controlling the fixed-frequency power generation of hydrogen internal combustion engines, the load of the hydrogen internal combustion engine generator set is adaptively adjusted within the power range of 0-10kW. When the load changes, the frequency of the output three-phase AC power is always controlled at 50±0.2Hz, realizing the control of the dynamic load fixed-frequency power generation of the hydrogen internal combustion engine generator set.

[0099] Therefore, the method and application of the constant speed and load adaptation of the hydrogen internal combustion engine without throttle control described in the present invention are adopted to realize the constant speed operation and load adaptation of the hydrogen internal combustion engine without relying on throttle adjustment, so that the intake volume control of the hydrogen internal combustion engine during startup, warm-up and power output states is more in line with the working conditions; the hydrogen internal combustion engine responds faster to real-time changes in load and has a more stable speed.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for self-adapting constant speed load of a hydrogen internal combustion engine without throttle control, characterized in that: The following steps are involved: S1. setting the throttle opening under the starting condition, warm-up condition, and power output condition of the hydrogen internal combustion engine respectively; S2, constant speed operation control in warm-up condition; S3. Constant speed load adaptive control of power output condition.

2. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 1, characterized in that: In S1 , a fixed throttle opening is maintained under the starting condition, the warm-up condition, and the constant speed power output condition.

3. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 2, characterized in that: The throttle opening is 5%-8% under the starting working condition, 10%-15% under the warm-up working condition, and 15%-100% under the power output working condition.

4. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 3, characterized in that: Under the power output operating condition, when the hydrogen internal combustion engine is running at a target speed of 25%-40% of the maximum speed, the throttle opening is 15%-20%; when the hydrogen internal combustion engine is running at a target speed of 40%-50% of the maximum speed, the throttle opening is 20%-25%; when the hydrogen internal combustion engine is running at a target speed of more than 50% of the maximum speed, the throttle opening is 100%.

5. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 1, characterized in that: In S2, the constant speed operation control in the warm-up condition includes the following steps: S21. Under the calibrated basic warm-up MAP and warm-up throttle opening, the hydrogen internal combustion engine operates at an actual speed, where the actual speed is 80%-120% of the target speed; S22, obtaining a PID control adjustment amount of an operating parameter based on the speed difference between the actual speed and the target speed; S23, obtaining MAP execution parameters based on the current actual speed and oil temperature of the hydrogen internal combustion engine and data in the calibrated basic warm-up MAP; S24, adding the PID control adjustment amount and the MAP execution parameter to obtain the actual operating parameters of the hydrogen internal combustion engine, and obtaining a new actual speed; S25. Repeat S22-S24, the actual speed converges to the target speed, and the hydrogen internal combustion engine maintains stable operation at the target speed until the warm-up process is completed.

6. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 5, characterized in that: In the step S21, the actual speed and the oil temperature are used as independent variables to calibrate the basic warm-up MAP. The parameter data of the calibrated basic warm-up MAP include the hydrogen injection pulse width, the ignition advance angle, and the hydrogen injection start time. In S23 , when the actual speed and the oil temperature are values of non-calibrated points, the MAP execution parameters are determined by performing two-dimensional linear interpolation on the data of the nearest calibration point.

7. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 1, characterized in that: In S3, the constant speed load adaptive control of the power output condition includes the following steps: S31, determining a power output throttle opening according to a target speed of the hydrogen internal combustion engine; S32. Under the calibrated basic operating MAP and power output throttle opening, the hydrogen internal combustion engine operates at an actual speed, where the actual speed is 80%-120% of the target speed; S33, reading the transient speed several times, and averaging the transient speed results read several times to obtain an average actual speed; S34, obtaining a PID control adjustment amount of the operating parameter by averaging the speed difference between the actual speed and the target speed; S35. Combining the calibrated basic working MAP, the average actual speed, and the load variable to obtain the MAP execution parameters in the calibrated basic working MAP; the load variable is a dummy variable; S36, adding the MAP execution parameter and the PID control adjustment amount to obtain the actual operating parameter of the hydrogen internal combustion engine, and obtaining a new actual speed; S37. Repeat S33-S36, the actual speed converges to the target speed, and the hydrogen internal combustion engine maintains stable operation at the target speed.

8. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 7, characterized in that: In the step S32, the actual speed and the load variable are used as independent variables to calibrate the basic working MAP, and the parameter data of the calibrated basic working MAP include the hydrogen injection pulse width, the ignition advance angle and the hydrogen injection start time; In the above S35 , when the actual speed and the load variable are values of non-calibrated points, the MAP execution parameters are determined by performing two-dimensional linear interpolation on the data of the nearest calibration point.

9. The method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control according to claim 7, characterized in that: The load variable is a function of the speed difference between the average actual speed and the target speed, and the rail pressure difference between the actual rail pressure and the calibrated rail pressure. When the speed difference and rail pressure difference are taken as values at non-calibrated points, the load variable value is determined by two-dimensional linear interpolation using the data from the nearest calibration point.

10. A method for self-adapting constant speed and load of a hydrogen internal combustion engine without throttle control as claimed in any one of claims 1 to 9, applied in constant frequency power generation and propeller driving of a hydrogen internal combustion engine.

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