Buffer tank pressure control system and method for alcohol hydrogen fuel engine

Abstract

The invention discloses a pressure control system and method for a buffer tank of an alcohol-hydrogen fuel engine. The system comprises a measuring unit, a processing unit, an execution unit and related accessory equipment. The measuring unit is used for measuring the pressure and the temperature of internal gas and converting a state quantity into an electric signal; the processing unit is connected with the measuring unit, comprises a fuzzy controller and an electronic control unit, and is used for processing a signal from the measuring unit, outputting a PWM (Pulse Width Modulation) signal according to a preset fuzzy control strategy and determining a duty ratio d; the execution unit is connected with the processing unit and comprises a high-speed electromagnetic valve for controlling ethanol supply of the reformer, and the execution unit controls the opening time of the high-speed electromagnetic valve according to the duty ratio d of a PWM signal output by the processing unit, so that the pressure of the buffer tank is adjusted; by adopting the fuzzy PWM control method, accurate control over the pressure of the buffer tank of the alcohol-hydrogen fuel engine is achieved, and the stability, robustness and adaptability of the system are improved.

Description

Technical Field

[0001] The invention relates to the field of engine fuel supply system control, and in particular to a pressure control system and method for a buffer tank of an alcohol-hydrogen fuel engine. Background Art

[0002] As a new type of renewable energy power device, alcohol hydrogen fuel engine has received widespread attention in recent years. With the continuous growth of global energy demand and the increasing depletion of fossil fuel resources, it has become a top priority to find a clean, efficient and sustainable energy alternative. Alcohol hydrogen fuel engine has gradually become a hot topic of research due to its high efficiency, environmental protection and sustainability.

[0003] However, in practical applications, alcohol-hydrogen fuel engines face many technical challenges. In particular, in the fuel supply system of the reformer online hydrogen production, the control of the buffer tank pressure has become an urgent problem to be solved. As an important component connecting the reformer and the engine, the stability of the internal pressure of the buffer tank is directly related to the working state of the engine. Due to the hysteresis of the vaporization of water-containing ethanol inside the reformer and various nonlinear factors in the ethanol supply process, such as changes in the chemical reaction rate and the dynamic characteristics of the fluid in the pipeline, the buffer tank pressure is prone to fluctuations, which in turn affects the power output, fuel economy and emission performance of the engine.

[0004] In response to the above challenges, the prior art has proposed a variety of solutions to improve the stability of the fuel supply system of the alcohol hydrogen fuel engine. One of the more common methods is to use a proportional integral differential (PID) controller to adjust the buffer tank pressure. Although the PID control strategy is simple in structure, easy to implement, and has been widely used in many industrial fields, it relies on an accurate mathematical model. For systems with uncertainty and nonlinear characteristics, the control effect is often unsatisfactory. Especially when there is hysteresis in the pressure change, PID control is difficult to achieve advance prediction and precise adjustment, resulting in the difficulty in effectively suppressing pressure fluctuations.

[0005] Based on the above analysis, it can be seen that there is currently a lack of an effective pressure control system on the market that can overcome the limitations of traditional control methods and meet the special needs of alcohol-hydrogen fuel engines. Therefore, it is particularly urgent to explore more advanced and reasonable control strategies to improve the pressure control accuracy of the buffer tank of alcohol-hydrogen fuel engines and enhance the system robustness and adaptability. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a pressure control system and method for a buffer tank of an alcohol-hydrogen fuel engine. The present invention achieves accurate control of the pressure of the buffer tank of an alcohol-hydrogen fuel engine by adopting a fuzzy PWM control method, thereby improving the stability, robustness and adaptability of the system. At the same time, the present invention also optimizes the switching process of the fuel supply mode, improves energy utilization efficiency, reduces costs, and is easy to debug and maintain.

[0007] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0008] In a first aspect, the present invention provides a pressure control system for a buffer tank of an alcohol hydrogen fuel engine, characterized in that it comprises:

[0009] The measuring unit is arranged on the buffer tank and the reformer, and is used to measure the pressure and temperature of the internal gas and convert the state quantity into an electrical signal;

[0010] a processing unit connected to the measuring unit, comprising a fuzzy controller and an electronic control unit, for processing the signal from the measuring unit, and outputting a PWM signal and determining a duty cycle d according to a preset fuzzy control strategy;

[0011] an execution unit connected to the processing unit, comprising a high-speed solenoid valve for controlling the supply of ethanol to the reformer, wherein the execution unit controls the opening time of the high-speed solenoid valve according to the duty cycle d of the PWM signal output by the processing unit, thereby adjusting the pressure of the buffer tank;

[0012] A mode switching valve switches between a gasoline fuel mode and an alcohol hydrogen fuel mode according to the pressure and / or temperature conditions of the buffer tank; wherein the reformer is directly connected to the buffer tank.

[0013] As a further technical solution of the present invention, the fuzzy controller adopts a fuzzy PWM control method, establishes fuzzy rules based on expert experience or existing data experience, and performs fuzzy reasoning through the Mamdani reasoning method. The clarification process adopts the area centroid method to achieve predictive control of the buffer tank pressure change.

[0014] As a further technical solution of the present invention, the fuzzy controller is designed with three variable inputs, including pressure difference ΔP, reformer pressure change rate dP1 / dt and reformer temperature T1, where ΔP=P–P1, P is the target pressure, and P1 is the reformer pressure.

[0015] As a further technical solution of the present invention, the fuzzy controller is designed with two variable inputs, including the dimension number X of the reformer pressure P1 and the temperature T1 and the reformer pressure change rate dP1 / dt, where X=P1 / T1.

[0016] As a further technical solution of the present invention, the domain boundary of the fuzzy controller adopts a bell-shaped membership function, and the remaining elements are trapezoidal or triangular membership functions.

[0017] As a further technical solution of the present invention, the duty cycle d∈[0,1], 0 represents that the high-speed solenoid valve is fully closed, and 1 represents that it is fully open; the corresponding control strategy is: when the pressure value ΔP≤P min -P, d = 0; when the pressure value is P min -P<ΔP<0, d∈(0,1]; when the pressure value ΔP=0, d=0; when the pressure value 0<ΔP <P max -P, d∈(0,1]; when the pressure value P max -P≤ΔP, d=0; where P min is the lower limit of pressure allowance, P max The upper limit of the allowable pressure.

[0018] In a second aspect, the present invention provides a method for controlling the pressure of a buffer tank of an alcohol hydrogen fuel engine, the method comprising the following steps:

[0019] The engine is started in gasoline fuel mode, using the heat generated by gasoline combustion to preheat the reformer;

[0020] When the pressure and temperature of the reformer reach the preset reaction conditions, it switches to alcohol-hydrogen fuel mode;

[0021] In alcohol-hydrogen fuel mode, the pressure and temperature signals of the reformer and buffer tank are collected in real time through the measuring unit, and these signals are input into the processing unit;

[0022] The fuzzy controller in the processing unit performs fuzzy reasoning based on the input pressure, temperature and their change rate using preset fuzzy rules and outputs the duty cycle of the PWM signal;

[0023] The execution unit controls the opening time of the high-speed solenoid valve according to the duty cycle, thereby adjusting the amount of ethanol entering the reformer and achieving precise control of the buffer tank pressure;

[0024] The actual pressure of the buffer tank is fed back to the processing unit, the output value is continuously corrected for closed-loop control, and the subsequent fuel mode is determined based on the pressure value.

[0025] As a further technical solution of the present invention, if the buffer tank pressure is lower than the preset pressure range, the alcohol-hydrogen fuel mode is exited and switched to the gasoline fuel mode for fuel supply, and the alcohol-hydrogen fuel mode is entered again after the pressure and temperature meet the conditions; if the buffer tank pressure is within the preset pressure range, the alcohol-hydrogen fuel mode is continued to be maintained; if the buffer tank pressure is higher than the preset pressure range, the safety valve is opened, and the alcohol-hydrogen fuel mode remains during this period.

[0026] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the buffer tank pressure control system for an alcohol-hydrogen fuel engine.

[0027] In a fourth aspect, the present invention provides a computer device, including a processor and a memory, wherein the memory stores a computer program, and when the processor executes the computer program, the buffer tank pressure control system for an alcohol-hydrogen fuel engine is implemented.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) By adopting the fuzzy PWM control method, the present invention can effectively solve the problem of pressure fluctuation in the buffer tank of the alcohol hydrogen fuel engine. The fuzzy controller can dynamically adjust the opening time of the high-speed solenoid valve based on the real-time collected pressure and temperature data, thereby realizing accurate control of the buffer tank pressure. This control method is more flexible and intelligent than traditional PWM control, and can significantly reduce the large fluctuation of pressure and improve the stability of the engine.

[0030] (2) The design of the fuzzy controller fully considers the hysteresis of the gasification of aqueous ethanol in the reformer and the nonlinearity and uncertainty of pressure changes. Through the fuzzy rules established by expert experience and existing data, the present invention can maintain high control accuracy and stability under different working conditions and environments. This design enables the system to maintain excellent robustness and adaptability in the face of complex and changeable operation.

[0031] (3) The present invention optimizes the switching of fuel supply modes, and realizes smooth switching between gasoline fuel mode and alcohol hydrogen fuel mode by real-time monitoring of the pressure and temperature of the reformer and the pressure of the buffer tank. This switching method not only improves the reliability and safety of the engine, but also can extend the service life of the engine to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the schematic diagram of the buffer tank pressure control technology for alcohol hydrogen fuel engines.

[0033] Figure 2 This is a diagram of the fuel supply system for an alcohol-hydrogen fuel engine.

[0034] Figure 3 This is the schematic diagram of the three-variable fuzzy controller.

[0035] Figure 4 This is the schematic diagram of the two-variable fuzzy controller.

[0036] Figure numerals: 1-high-speed solenoid valve; 2-reformer; 3-pressure sensor; 4-temperature sensor; 5-safety valve; 6-buffer tank; 7-engine; 8-drain valve; 9-mode switching valve; 10-processing unit. DETAILED DESCRIPTION

[0037] The specific implementation of the present invention is described below in conjunction with the accompanying drawings to facilitate the understanding of the present invention by those skilled in the art. Obviously, the present invention is not limited to the scope of the specific implementation. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are non-creative work, and all inventions and creations using the invention concept of this law are protected.

[0038] Example 1: Application of three-variable input fuzzy PWM control system in alcohol-hydrogen fuel engine

[0039] like Figure 1-Figure 3 As shown, this embodiment provides a pressure control system for a buffer tank of an alcohol-hydrogen fuel engine, including a measuring unit, a processing unit, an execution unit and related auxiliary equipment. The measuring unit includes a pressure sensor 3 and a temperature sensor 4, both of which are arranged on the buffer tank 6 and the reformer 2, for measuring the pressure and temperature of the internal gas and converting the state quantity into an electrical signal. The processing unit 10 is connected to the measuring unit, including a fuzzy controller FC and an electronic control unit ECU, for processing the signal from the measuring unit, and outputting a PWM signal and determining the duty cycle d according to a preset fuzzy control strategy. The execution unit is connected to the processing unit, including a high-speed solenoid valve 1 for controlling the ethanol supply of the reformer, and the execution unit controls the opening time of the high-speed solenoid valve according to the duty cycle d of the PWM signal output by the processing unit, thereby adjusting the pressure of the buffer tank. The high-speed solenoid valve 1 has a continuous output characteristic similar to that of a proportional valve.

[0040] Related auxiliary equipment includes a mode switching valve 9, a residual discharge valve 8 and a safety valve 5. The mode switching valve 9 switches between the gasoline fuel mode and the alcohol hydrogen fuel mode according to the pressure and / or temperature conditions of the reformer; wherein, the reformer 2 is directly connected to the buffer tank 6, and there are no valves in the connecting pipeline. The pressures of the two are balanced with each other, and the pressure of the buffer tank 6 can be indirectly controlled by controlling the pressure of the reformer 2. When the pressure is too high, the safety valve 5 opens to prevent overpressure. The residual discharge valve 8 is used to return the residual liquid in the buffer tank 6 to the ethanol storage container. The reformer 2 and the buffer tank 6 should have insulation facilities to reduce the impact of heat transfer on the cracking rate and the consistency of temperature.

[0041] The engine 7 is started in the gasoline fuel mode, and gasoline is initially supplied to the engine through the mode switching valve. The temperature sensor on the reformer collects temperature value signals and inputs them into the processing unit.

[0042] Further, when the temperature reaches the threshold value T, the ECU switches the fuel mode and the engine enters the alcohol-hydrogen fuel mode. The reformer alcohol supply high-speed solenoid valve opens and ethanol enters the reformer.

[0043] Further, when the reformer pressure reaches the pressure threshold value P, the mode switching valve opens the ethanol supply passage and cuts off the gasoline supply passage, and ethanol is supplied to the engine as fuel.

[0044] The linkage modes of the mode switching valve ethanol valve and gasoline valve are summarized in the following table:

[0045]

[0046] Furthermore, in the alcohol hydrogen fuel mode, when the reformer pressure and temperature reach the expected range, the pressure and temperature sensors collect pressure signals, and the pressure and temperature signals enter the fuzzy controller. The fuzzy controller outputs a duty cycle value, which determines the opening time of the high-speed solenoid valve, and takes the reformer as the controlled object to further control the buffer tank pressure.

[0047] Furthermore, in the fuzzy controller design process:

[0048] The target pressure P(P should be within the range pressure(P min ,P max ), P1 is the reformer pressure, P2 is the buffer tank pressure, ΔP=P–P1 is the difference between the target pressure and the reformer pressure, where P1≈P2. The reformer reaction temperature is T1, the buffer tank temperature is T2, where T1≈T2.

[0049] Fuzzy controller configuration: When three variables are used as input FC, the domain is ΔP (P-P1), dP1 / dt (reformer pressure change rate), T1 (reformer temperature), and the output variable is PWM duty cycle d. The domain can be divided into different symmetric intervals [-n, n] according to the applicable scenario, and the level of fuzzy subsets can be divided according to the control accuracy (for example, when there are 7 fuzzy levels, they are negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM) and positive large (PB)). The domain boundaries of input quantities ΔP, dP1 / dt, and T1 preferably use bell-shaped membership functions, and the other levels use triangular membership functions to improve input sensitivity.

[0050] The domain of the output value d can be divided into different levels in the interval [0,1] according to the applicable scenario, and the domain level is set according to the control accuracy (for example, when there are 5 fuzzy levels, they are negative large (NB), negative small (NS), zero (ZO), positive small (PS), and positive large (PB)). The domain boundary of the output value d preferably uses a bell-shaped function as the membership function, and the remaining elements are trapezoidal membership functions to ensure a certain plateau period, so that the output is far away from the domain boundary while improving its stability. When evaluating the value range of d, this method adopts the following steps:

[0051] ① Fixed step length sampling airspeed Q;

[0052] ②Determine the mass flow rate v m Range:

[0053] v m =Q*V*ρ

[0054] V is the volume of the catalyst stack; ρ is the density of the gas at the temperature and pressure;

[0055] ③ Determine the pulse width at maximum flow and the pulse width at minimum flow according to the valve aperture and other parameters;

[0056] ④ The maximum pulse width is determined to be 1, and the minimum pulse width is determined to be a value to the right of 0 (which is less than 1).

[0057] Fuzzy rule establishment: Establish a fuzzy rule base based on expert experience and existing data experience.

[0058] For the establishment of fuzzy rules in this method, tabular fuzzy rules established through experimental data are more appropriate, and their accuracy and program execution efficiency are higher.

[0059] The output and input are divided into n+1 levels (n is usually 2, 4, 6). For the output, a discrete number is used to represent each level. The 5-level output d is taken as an example to illustrate the specific fuzzy rule establishment method.

[0060] ① Use <-2, -1, 0, 1, 2> to represent the five different levels of d (NM, NS, ZO, PS, PM);

[0061] ② For each experimental data, it corresponds to a fuzzy rule, which summarizes the relationship between input and output, and the same ones are assigned to one rule;

[0062] ③ For the case of the same input but different output, a weighted rounding method is adopted. The specific steps are as follows:

[0063] Ⅰ Repeat the experiment n times and record;

[0064] Ⅱ There are x times of the same input, with a -2 output, b -1 output, c 0 output, e 1 output, and f 2 output;

[0065] III For each output weighted value, take

[0066]

[0067] IV Weighted d i for:

[0068] d i =∑ω j N,N=-2,-1,0,1,2

[0069] After weighting, we can take the following approach to round to get d j :

[0070]

[0071] The "sgn" operator represents the i Take the same sign;

[0072] The "int" operator represents the value of (|d i |+0.5).

[0073] ④Convert the obtained discrete digital levels into corresponding symbolic levels, or use them directly to improve convenience;

[0074] ⑤Finally, organize each rule to obtain the final tabular fuzzy rules.

[0075] This method is used to establish fuzzy rules, which reduces the degree of dependence on the membership function and also reduces the complexity of the model to a certain extent.

[0076] The fuzzy logic reasoning process is performed using the Mamdani reasoning method.

[0077] In the reasoning process, the reasoning form of if..., then... is adopted. For the total implication relation R, not all rules will be activated every time an input is input, so only the activated rules need to be operated. Its operation form is:

[0078]

[0079] R j represents the jth fuzzy rule;

[0080] represents the relational composition operator;

[0081] It represents the transpose of the input quantity relationship after synthesis and straightening;

[0082] D represents the output quantity inferred according to fuzzy rules.

[0083] Clarification: After fuzzy reasoning, the area centroid method is used for clarification to obtain an accurate duty cycle d value. The area centroid method is: synthesize the relationship between each input obtained after reasoning and the activated fuzzy rule, take the union, and use the fuzzy function of the output value to form a closed figure, and obtain the centroid coordinates of this figure, and its corresponding horizontal coordinate is the output value.

[0084] PWM signal output and execution: The duty cycle d output by the fuzzy controller controls the opening time of the high-speed solenoid valve, adjusts the amount of ethanol entering the reformer, and thus indirectly controls the buffer tank pressure.

[0085] In PWM control:

[0086] The duty cycle d is used to represent the control of the valve under PWM state, where d∈[0,1]. In this control cycle, 0 represents the fully closed switch valve, and 1 represents the fully opened valve. The corresponding control strategy is summarized as:

[0087] Pressure value <![CDATA[ΔP≤P min -P]]> <![CDATA[P min -P<ΔP<0]]> ΔP=0 <![CDATA[0<ΔP<P max -P]]> <![CDATA[P max -P≤ΔP]]> Spool status 0 (0，1] 0 (0，1] 0

[0088] Allowable lower limit of pressure: P min ; Upper limit of pressure allowance: P max .

[0089] Set the valve core power-on time to t on , the valve core power-off time is t off , the entire signal period is t.

[0090] The entire response process of the switch valve can be divided into three areas: dead zone, linear zone and saturation zone. In the dead zone, the PWM high-level signal time is less than the opening time of the switch valve, and the solenoid valve core cannot be opened; in the linear zone, the effective cross-sectional area of ​​the solenoid valve core and the duty cycle are approximately linearly related; in the saturation zone, the low-level signal time is less than the closing time, and the solenoid valve core cannot be closed. Carrier signal period selection principle:

[0091] t≥t on +t off

[0092] Due to the inertia of the valve, magnetic hysteresis and the delay in pressure rise, the duty cycle has a maximum value.

[0093]

[0094] During the opening time of the high-speed solenoid valve at the input duty cycle, aqueous ethanol enters the reformer and is then fed back to the processing module based on the buffer tank pressure to determine subsequent input.

[0095] Actual pressure feedback: The actual pressure P2 of the buffer tank is fed back to the fuzzy controller through the sensor, and the duty cycle d is continuously adjusted to form a closed-loop control.

[0096] Furthermore, the actual pressure is fed back to the processing unit, and the subsequent mode is determined according to the pressure value. The subsequent mode can be summarized into three situations:

[0097] Ⅰ. If the pressure is lower than the ideal pressure range, exit the alcohol-hydrogen fuel mode and switch to the gasoline fuel mode for fuel supply. When the pressure and temperature meet the conditions, enter the alcohol-hydrogen fuel mode again.

[0098] Ⅱ. If the pressure value is ideal, continue to maintain the alcohol hydrogen fuel mode.

[0099] Ⅲ. If the pressure is too high, the safety valve opens and the fuel mode remains alcohol-hydrogen fuel mode.

[0100] Furthermore, the residual liquid in the buffer tank flows back to the ethanol storage container through the residual drain valve.

[0101] Example 2: Application of two-variable input fuzzy PWM control system in alcohol-hydrogen fuel engine

[0102] like Figure 2 As shown, the main difference between this embodiment and embodiment 1 lies in the design of the fuzzy controller. When two variables are input to FC, similar to three variables FC, when setting the fuzzy subset, the two inputs P1 and T1 are coupled. In this scheme, let the FC input be X (X = P1 / T1) and dP1 / dt, the domain of X is (0, n], the domain of dP1 / dt is [-n, n], and the rest of the steps are the same as the three variables FC. Compared with the three variables FC, although the control accuracy is reduced, the response time can be significantly improved.

[0103] Fuzzy rule adjustment: According to the changes of X and dP1 / dt, the PWM duty cycle d is adjusted to quickly respond to pressure fluctuations.

[0104] The remaining steps: fuel mode switching, PWM signal output and execution, feedback and adjustment, and system maintenance are the same as those in Example 1.

[0105] The present invention adopts fuzzy PWM control, sets fuzzy sets for input and output, and in the fuzzy rules established by expert experience, elements of different levels in the set correspond to different numerical intervals. By adjusting the value range of the elements in the fuzzy set, the parameters of the membership function and adopting different fuzzy rules, a good control effect is achieved on the hysteresis of pressure rise and the excessively fast pressure change exceeding the lower limit of the tolerable pressure. The fuzzy rules designed by expert experience can realize the effective control of the complex system of pressure change, and its robustness and adaptability can easily meet the requirements after actual debugging.

[0106] The present invention provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the pressure control system for a buffer tank of an alcohol-hydrogen fuel engine is realized.

[0107] The present invention provides a computer device, comprising a processor and a memory, wherein a computer program is stored in the memory, and when the processor executes the computer program, the pressure control system for a buffer tank of an alcohol-hydrogen fuel engine is realized.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0109] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. A pressure control system for a buffer tank of an alcohol hydrogen fuel engine, characterized in that: include: The measuring unit is arranged on the buffer tank and the reformer, and is used to measure the pressure and temperature of the internal gas and convert the state quantity into an electrical signal; a processing unit connected to the measuring unit, comprising a fuzzy controller and an electronic control unit, for processing the signal from the measuring unit, and outputting a PWM signal and determining a duty cycle d according to a preset fuzzy control strategy; an execution unit connected to the processing unit, comprising a high-speed solenoid valve for controlling the supply of ethanol to the reformer, wherein the execution unit controls the opening time of the high-speed solenoid valve according to the duty cycle d of the PWM signal output by the processing unit, thereby adjusting the pressure of the buffer tank; A mode switching valve switches between a gasoline fuel mode and an alcohol hydrogen fuel mode according to the pressure and / or temperature conditions of the buffer tank; wherein the reformer is directly connected to the buffer tank.

2. The pressure control system for the buffer tank of an alcohol hydrogen fuel engine according to claim 1, characterized in that: The fuzzy controller adopts a fuzzy PWM control method, establishes fuzzy rules based on expert experience or existing data experience, and performs fuzzy reasoning through the Mamdani reasoning method. The clarification process adopts the area centroid method to achieve predictive control of buffer tank pressure changes.

3. The pressure control system for a buffer tank of an alcohol hydrogen fuel engine according to claim 1 or 2, characterized in that: The fuzzy controller is designed with three variable inputs, including the pressure difference ΔP, the reformer pressure change rate dP1 / dt and the reformer temperature T1, where ΔP = P-P1, P is the target pressure, and P1 is the reformer pressure.

4. The pressure control system for a buffer tank of an alcohol hydrogen fuel engine according to claim 1 or 2, characterized in that: The fuzzy controller is designed for two variable inputs, including the dimension number X of the reformer pressure P1 and temperature T1 and the reformer pressure change rate dP1 / dt, where X=P1 / T1.

5. The pressure control system for the buffer tank of an alcohol hydrogen fuel engine according to claim 1, characterized in that: The domain boundary of the fuzzy controller adopts a bell-shaped membership function, and the remaining elements are trapezoidal or triangular membership functions.

6. The pressure control system for the buffer tank of an alcohol hydrogen fuel engine according to claim 1, characterized in that: The duty cycle d∈[0,1], 0 represents that the high-speed solenoid valve is fully closed, and 1 represents that it is fully open; the corresponding control strategy is: when the pressure value ΔP≤P min -P, d = 0; when the pressure value is P min -P<ΔP<0, d∈(0,1]; When the pressure value ΔP=0, d=0; when the pressure value 0<ΔP <P max -P, d∈(0,1]; when the pressure value P max -P≤ΔP, d=0; where P min is the lower limit of pressure allowance, P max The upper limit of the allowable pressure.

7. A method for controlling the pressure of a buffer tank of an alcohol hydrogen fuel engine, characterized in that: Using the buffer tank pressure control system for an alcohol hydrogen fuel engine according to any one of claims 1 to 6, the method comprises the following steps: The engine is started in gasoline fuel mode, using the heat generated by gasoline combustion to preheat the reformer; When the pressure and temperature of the reformer reach the preset reaction conditions, it switches to alcohol-hydrogen fuel mode; In alcohol-hydrogen fuel mode, the pressure and temperature signals of the reformer and buffer tank are collected in real time through the measuring unit, and these signals are input into the processing unit; The fuzzy controller in the processing unit performs fuzzy reasoning based on the input pressure, temperature and their change rate using preset fuzzy rules and outputs the duty cycle of the PWM signal; The execution unit controls the opening time of the high-speed solenoid valve according to the duty cycle, thereby adjusting the amount of ethanol entering the reformer and achieving precise control of the buffer tank pressure; The actual pressure of the buffer tank is fed back to the processing unit, the output value is continuously corrected for closed-loop control, and the subsequent fuel mode is determined based on the pressure value.

8. The method for controlling the pressure of a buffer tank of an alcohol hydrogen fuel engine according to claim 7, characterized in that: If the buffer tank pressure is lower than the preset pressure range, the alcohol-hydrogen fuel mode is exited and switched to the gasoline fuel mode for fuel supply. The alcohol-hydrogen fuel mode is entered again after the pressure and temperature meet the conditions. If the buffer tank pressure is within the preset pressure range, the alcohol-hydrogen fuel mode will continue to be maintained; If the buffer tank pressure is higher than the preset pressure range, the safety valve opens and the alcohol-hydrogen fuel mode remains during this period.

9. A computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the buffer tank pressure control system for an alcohol-hydrogen fuel engine according to any one of claims 1 to 6 is implemented.

10. A computer device, comprising a processor and a memory, wherein the memory stores a computer program, and when the processor executes the computer program, the pressure control system for a buffer tank of an alcohol hydrogen fuel engine according to any one of claims 1 to 6 is implemented.

Images