A buffer tank pressure control system and method for alcohol hydrogen fuel engines

Abstract

The application discloses a kind of for alcohol hydrogen fuel engine buffer tank pressure control system and method, the system includes measurement unit, processing unit, execution unit and related accessory equipment.Measurement unit is used to measure the pressure and temperature of internal gas, and state quantity is converted into electrical signal;Processing unit is connected with measurement unit, including fuzzy controller and electronic control unit, for processing signal from measurement unit, and according to the preset fuzzy control strategy output PWM signal and determine duty cycle d;Execution unit is connected with processing unit, including control reformer ethanol supply's high-speed electromagnetic valve, execution unit according to the duty cycle d of PWM signal output by processing unit to control the opening time of high-speed electromagnetic valve, to adjust the pressure of buffer tank;The present application realizes the accurate control of alcohol hydrogen fuel engine buffer tank pressure by adopting fuzzy PWM control method, improves the stability, robustness and adaptability of system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine fuel supply system control, in particular to a buffer tank pressure control system and method for alcohol hydrogen fuel engine. BACKGROUND

[0002] Alcohol hydrogen fuel engine as a new type of renewable energy power device has received widespread attention in recent years. With the growing global energy demand and the depletion of fossil fuel resources, it has become urgent to find a clean, efficient and sustainable energy alternative. Alcohol hydrogen fuel engine has gradually become a research hotspot due to its high efficiency, environmental protection and sustainability.

[0003] However, in practical applications, alcohol hydrogen fuel engine faces many technical challenges. In particular, in the fuel supply system of the reformer online hydrogen production, the control of the buffer tank pressure becomes a 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 water-containing ethanol gasification in the reformer and various nonlinear factors in the ethanol liquid supply process, such as changes in chemical reaction rate, dynamic characteristics of fluid in the pipeline, etc., the buffer tank pressure is prone to fluctuation, which in turn affects the power output, fuel economy and emission performance of the engine.

[0004] In view of the above challenges, the existing technology proposes various solutions to improve the stability of the fuel supply system of alcohol hydrogen fuel engine. One of the more common methods is to use a proportional-integral-derivative (PID) controller to adjust the pressure of the buffer tank. Although the PID control strategy is simple in structure and easy to implement, and has been widely used in many industrial fields, due to its dependence on accurate mathematical models, for systems with uncertainty and nonlinear characteristics, the control effect is often not satisfactory. Especially in the case of hysteresis of pressure change, PID control is difficult to achieve advanced prediction and accurate adjustment, resulting in difficulty in effectively suppressing pressure fluctuations.

[0005] In view of the above analysis, it can be seen that there is a lack of an effective pressure control system in the market that can overcome the limitations of traditional control methods and meet the special needs of alcohol hydrogen fuel engine. Therefore, it is particularly urgent to explore more advanced and reasonable control strategies to improve the control precision of the buffer tank pressure of alcohol hydrogen fuel engine, enhance the robustness and adaptive ability of the system. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application aims to provide a buffer tank pressure control system and method for alcohol-hydrogen fuel engine. The present application realizes accurate control of the buffer tank pressure of the alcohol-hydrogen fuel engine by adopting a fuzzy PWM control method, and improves the stability, robustness and adaptability of the system. Meanwhile, the present application also optimizes the switching process of the fuel supply mode, improves the energy utilization efficiency, reduces the cost, and is easy to debug and maintain.

[0007] To solve the above technical problems, the present application realizes the following technical solutions:

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

[0009] a measurement unit arranged on the buffer tank and the reformer, for measuring the pressure and temperature of the internal gas and converting the state quantity into an electrical signal;

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

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

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

[0013] As a further technical solution of the present application, the fuzzy controller adopts a fuzzy PWM control method, establishes fuzzy rules based on expert experience or existing data experience, and performs fuzzy reasoning by Mamdani reasoning method, and the defuzzification process adopts area barycenter method, so as to realize the predictive control of the pressure change of the buffer tank.

[0014] As a further technical solution of the present application, the fuzzy controller is designed as a three-variable input, including the pressure difference ΔP, the reformer pressure change rate dP1 / dt and the reformer temperature T1, wherein ΔP=P-P1, P is the target pressure, and P1 is the reformer pressure.

[0015] As a further technical solution of the present application, the fuzzy controller is designed as a two-variable input, including the dimensionless number X of the reformer pressure P1 and temperature T1 and the reformer pressure change rate dP1 / dt, wherein X=P1 / T1.

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

[0017] As a further technical scheme of the present application, the duty cycle d∈[0,1], 0 represents that the high-speed electromagnetic valve is completely closed, and 1 represents that the high-speed electromagnetic valve is completely opened; the corresponding control strategy is: when the pressure value ΔP≤P min -P, d=0; when the pressure value 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; wherein P min is a lower limit of pressure tolerance, and P max is an upper limit of pressure tolerance.

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

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

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

[0021] In the alcohol hydrogen fuel mode, the pressure and temperature signals of the reformer and the buffer tank are collected in real time by a measurement unit, and the signals are input to a processing unit;

[0022] A fuzzy controller in the processing unit performs fuzzy reasoning according to the input pressure, temperature and their change rates, and outputs the duty cycle of the PWM signal by using preset fuzzy rules;

[0023] The execution unit controls the opening time of the high-speed electromagnetic valve according to the duty cycle, so as to adjust the amount of ethanol entering the reformer, and realizes accurate 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 according to the pressure value.

[0025] As a further technical scheme of the present application, if the buffer tank pressure is lower than the preset pressure range, the alcohol hydrogen fuel mode is exited, the gasoline fuel mode is switched to 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 continuously maintained; if the buffer tank pressure is higher than the preset pressure range, the safety valve is opened, and the alcohol hydrogen fuel mode is still maintained during the period.

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

[0027] In a fourth aspect, the present application provides a computer device comprising a processor and a memory, wherein the memory has stored thereon a computer program which, when executed by the processor, implements the buffer tank pressure control system for alcohol-hydrogen fuel engine.

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

[0029] (1) By adopting the fuzzy PWM control method, the present application can effectively solve the problem of pressure fluctuation of the alcohol-hydrogen fuel engine buffer tank. The fuzzy controller can dynamically adjust the opening time of the high-speed electromagnetic 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 the traditional PWM control, 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 water-containing ethanol gasification in the reformer and the nonlinearity and uncertainty of pressure change. Through the fuzzy rules established based on expert experience and existing data, the present application can maintain high control precision and stability under different working conditions and environments. This design enables the system to maintain excellent robustness and adaptability when facing complex and variable operation.

[0031] (3) The present application optimizes the switching of the fuel supply mode, realizes smooth switching between the gasoline fuel mode and the 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 prolong the service life of the engine to a certain extent. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The technical principle diagram for the buffer tank pressure control of the alcohol-hydrogen fuel engine.

[0033] Figure 2 The composition diagram of the fuel supply system of the alcohol-hydrogen fuel engine.

[0034] Figure 3 The principle diagram of the three-variable fuzzy controller.

[0035] Figure 4 The principle diagram of the two-variable fuzzy controller.

[0036] Reference numerals: 1-High-speed solenoid valve; 2-Reformer; 3-Pressure sensor; 4-Temperature sensor; 5-Safety valve; 6-Buffer tank; 7-Engine; 8-Residual discharge valve; 9-Mode switching valve; 10-Processing unit. Detailed Implementation

[0037] The specific embodiments of the present invention will now be described with reference to the accompanying drawings to enable those skilled in the art to understand the invention. Obviously, the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, any modifications within the spirit and scope of the invention as defined and determined by the appended claims are considered non-creative and all inventions utilizing the inventive concept of this method are protected.

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

[0039] like Figures 1-3 As shown, this embodiment provides a pressure control system for a buffer tank in an alcohol-hydrogen fuel cell engine, including a measurement unit, a processing unit, an execution unit, and related auxiliary equipment. The measurement unit includes a pressure sensor 3 and a temperature sensor 4, both arranged on the buffer tank 6 and the reformer 2, for measuring the pressure and temperature of the internal gas and converting the state variables into electrical signals. The processing unit 10 is connected to the measurement unit and includes a fuzzy controller FC and an electronic control unit ECU, for processing signals from the measurement 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 and includes a high-speed solenoid valve 1 that controls the ethanol supply to the reformer. 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 regulating the pressure of the buffer tank. The high-speed solenoid valve 1 has a continuous output characteristic similar to a proportional valve.

[0040] Related auxiliary equipment includes a mode switching valve 9, a residual liquid discharge valve 8, and a safety valve 5. The mode switching valve 9 switches between gasoline fuel mode and ethanol-hydrogen fuel mode based on the reformer's pressure and / or temperature conditions. The reformer 2 and buffer tank 6 are directly connected without valves in the connecting pipeline; their pressures are balanced, and controlling the pressure of the reformer 2 indirectly controls the pressure of the buffer tank 6. When the pressure is too high, the safety valve 5 opens to prevent overpressure. The residual liquid discharge valve 8 is used to return the residual liquid in the buffer tank 6 to the ethanol storage container. The reformer 2 and buffer tank 6 should have insulation to reduce the impact of heat transfer on the cracking rate and ensure temperature consistency.

[0041] Engine 7 starts in gasoline fuel mode, initially supplying fuel to the engine with gasoline through the mode switching valve. A temperature sensor on the reformer collects temperature signals and inputs them to the processing unit.

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

[0043] Further, when the reformer pressure reaches the pressure threshold P, the mode switching valve alcohol supply path opens, and the gasoline supply path is disconnected, and alcohol is supplied as fuel to the engine.

[0044] The linkage mode of the mode switching valve alcohol valve and the gasoline valve is summarized as follows:

[0045]

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

[0047] Further, in the design process of the fuzzy controller:

[0048] Target pressure P (P should be within the range of pressure (P min ,P max ), which meets the engine demand), 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, wherein P1≈P2. Let the reformer reaction temperature be T1, and the buffer tank temperature be T2, wherein T1≈T2.

[0049] Fuzzy controller configuration: when using three-variable input FC, the domain is ΔP (P-P1), dP1 / dt (reformer pressure change rate), and T1 (reformer temperature), and the output variable is PWM duty cycle d. Among them, the domain can be divided into different symmetric intervals [-n, n] according to the applicable situation, and the level of fuzzy subsets is 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 input quantity ΔP, dP1 / dt, and T1 domain boundary preferentially adopts a bell-shaped membership function, and the remaining levels select a triangular membership function to improve input sensitivity.

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

[0051] ①Fixed step sampling air speed Q;

[0052] ②Determine the range of mass flow v m :

[0053] v m = Q*V*ρ

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

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

[0056] ④Set the maximum pulse width to 1, and set the minimum pulse width to 0 on the right side of a certain value (which is less than 1).

[0057] Fuzzy rule establishment: according to expert experience and existing data experience, establish a fuzzy rule base.

[0058] For the establishment of fuzzy rules in this method, the table type fuzzy rules established by experimental data are more suitable, and the accuracy and program execution efficiency are higher.

[0059] Divide the output and input into n+1 (n is generally taken as 2, 4, 6) levels. For the output, take discrete numbers to represent each level. Take the 5-level output d as an example to illustrate the specific fuzzy rule establishment method.

[0060] ①Use <-2, -1, 0, 1, 2> to represent the 5 different levels of d (NM, NS, ZO, PS, PM);

[0061] ②For each experimental data, it corresponds to a fuzzy rule, and the relationship between the input and output is summarized, and the same is summarized as one;

[0062] ③For the case where the output is different for the same input, a weighted rounding method is adopted, and the specific steps are as follows:

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

[0064] II Total x times the same input, a times -2 output, b times -1 output, c times 0 output, e times 1 output, f times 2 output;

[0065] III For each output of the weighted value, take

[0066]

[0067] IV After weighting d i is:

[0068] d i =∑ω j N,N = -2,-1,0,1,2

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

[0070]

[0071] The "sgn" operator means to take the same sign as d i ;

[0072] The "int" operator means to take the integer part of (|d i |+0.5).

[0073] IV The obtained discrete digital level is converted into the corresponding symbol level, or directly used to improve convenience;

[0074] V Finally, each rule is sorted to obtain the final tabular fuzzy rule.

[0075] Using this method to establish fuzzy rules, while reducing the degree of dependence on membership functions, also reduces the complexity of the model to a certain extent.

[0076] Mamdani inference method is used to perform fuzzy logic reasoning process.

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

[0078]

[0079] R j represents the jth fuzzy rule;

[0080] represents the relationship composition operator;

[0081] represents the input quantity relationship composition after straightening the transpose;

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

[0083] Clearing processing: after fuzzy inference, the area barycenter method is used for clearing processing to obtain the accurate duty cycle d value. Among them, the area barycenter method is: the relationship between each input obtained after inference and the activated fuzzy rule is synthesized, the union is taken, and the fuzzy function of the output value is used to express it, and a closed figure is constructed. The barycentric coordinates of this figure are obtained, and the corresponding abscissa 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 electromagnetic valve, adjusts the amount of ethanol entering the reformer, and 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], 0 represents that the on-off valve is completely closed, and 1 represents that it is completely opened. The corresponding control strategy is summarized as:

[0087] Pressure value ΔP ≤ P min -P]]> P min -P<ΔP<0]]> ΔP = 0 0 < ΔP < P max -P]]> P max -P≤ΔP]]> Valve core state 0 (0，1] 0 (0，1] 0

[0088] Lower limit of pressure tolerance: P min ; Upper limit of pressure tolerance: P max .

[0089] The valve core energizing time is set as t on , the valve core de-energizing time is t off , and the whole signal period is t.

[0090] The whole response process of the on-off valve can be divided into three regions: dead zone, linear region and saturation region. In the dead zone, the PWM high level signal time is less than the opening time of the on-off valve, and the electromagnetic valve core cannot be opened; in the linear region, the effective cross-sectional area of the electromagnetic valve core is approximately linearly related to the duty cycle; in the saturation region, the low level signal time is less than the closing time, and the electromagnetic valve core cannot be closed. The selection principle of the carrier signal period is:

[0091] t≥t on +t off

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

[0093]

[0094] The high-speed electromagnetic valve is opened for a certain time under the input duty cycle, and then the water-containing ethanol enters the reformer, and then according to the buffer tank pressure, feedback to the processing module to determine the subsequent input.

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

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

[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, the alcohol hydrogen fuel mode is entered again.

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

[0099] III. If the pressure is too high, the safety valve is opened, and the alcohol hydrogen fuel mode is still used.

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

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

[0102] As shown in Figure 2 , the main difference between this embodiment and example 1 is the design of the fuzzy controller. When using two-variable input FC, similar to three-variable FC, the input P1 and T1 are coupled when setting the fuzzy subsets. In this scheme, the FC input is X (X=P1 / T1) and dP1 / dt, the domain of X is (0,n], and the domain of dP1 / dt is [-n,n]. The remaining steps are the same as those of three-variable FC. Compared with three-variable FC, although the control accuracy decreases, 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 operations are the same as those of example 1.

[0105] The present application uses fuzzy PWM control, sets fuzzy sets for input and output, and in the fuzzy rules established by expert experience, different levels of elements in the set correspond to different value intervals. By adjusting the value range of elements in the fuzzy set, the parameters of membership functions, and adopting different fuzzy rules, the hysteresis of pressure rise and the rapid pressure change exceeding the lower limit of tolerance pressure can be well controlled. Through the fuzzy rules designed by expert experience, the complex system of pressure change can be effectively controlled, and the robustness and adaptability can easily meet the requirements after actual debugging.

[0106] The application provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the alcohol hydrogen fuel engine buffer tank pressure control system.

[0107] The application provides a computer device, which comprises a processor and a memory, and the memory stores a computer program, and the processor executes the computer program to realize the alcohol hydrogen fuel engine buffer tank pressure control system.

[0108] The above merely describes preferred embodiments of the application and is not used to limit the application, and any modification, equivalent replacement and improvement within the spirit and principle of the application should be included in the protection scope of the application.

[0109] The content not described in detail in the specification of the application belongs to the prior art known by the person skilled in the art.

Claims

1. A buffer tank pressure control system for an alcohol hydrogen fuel engine, characterized by, The system comprises: a measuring unit arranged on the buffer tank and the reformer for measuring the pressure and temperature of the gas inside the reformer and converting the state quantities into electrical signals; a processing unit connected with the measuring unit, comprising a fuzzy controller and an electronic control unit, for processing the signals from the measuring unit and outputting a PWM signal and determining the duty cycle d according to a preset fuzzy control strategy; an execution unit connected with the processing unit, comprising a high-speed electromagnetic valve for controlling the supply of ethanol to the reformer, the execution unit controlling the opening time of the high-speed electromagnetic valve according to the duty cycle d of the PWM signal output by the processing unit, so as to adjust the pressure of the buffer tank; a mode switching valve for switching between the gasoline fuel mode and the alcohol-hydrogen fuel mode according to the pressure and / or temperature conditions of the buffer tank; wherein the reformer is directly connected with the buffer tank.

2. The buffer tank pressure control system for alcohol hydro- fuel engine according to claim 1, wherein The fuzzy controller adopts a fuzzy PWM control method, establishes fuzzy rules based on expert experience or existing data experience, and performs fuzzy reasoning by the Mamdani reasoning method, and the defuzzification process adopts the area barycenter method, so as to realize the prediction control of the pressure change of the buffer tank.

3. The buffer tank pressure control system for an alcohol hydro- fuel engine according to claim 1 or 2, characterized by, The fuzzy controller is designed as a three-variable input, comprising a reformer pressure difference ΔP, a reformer pressure change rate dP1 / dt and a reformer temperature T1, wherein ΔP = P - P1, P is a target pressure, and P1 is a reformer pressure.

4. The buffer tank pressure control system for alcohol hydrogen fuel engine according to claim 1 or 2, characterized in that, The fuzzy controller is designed as a two-variable input, comprising a dimensionless number X of the reformer pressure P1 and temperature T1 and a reformer pressure change rate dP1 / dt, wherein X = P1 / T1.

5. The buffer tank pressure control system for alcohol hydro- fuel engine according to claim 1, wherein The universe boundary of the fuzzy controller adopts a bell-shaped membership function, and the rest of the elements are trapezoidal or triangular membership functions.

6. The buffer tank pressure control system for alcohol hydrox fuel engine according to claim 3, wherein The duty cycle d∈[0,1], 0 represents that the high-speed electromagnetic valve is completely closed, and 1 represents that the high-speed electromagnetic valve is completely opened; and the corresponding control strategy is: when the pressure value ΔP≤P min -P, d=0; when the pressure value P min -P <ΔP<0, d∈(0,1]. d = 0 when the pressure value ΔP = 0; d ∈ (0, 1] when the pressure value 0 < ΔP < P max -P; d = 0 when the pressure value P max -P ≤ ΔP; where P min is the lower limit of the pressure tolerance, and P max is the upper limit of the pressure tolerance.

7. A method for buffer tank pressure control of an alcohol hydrogen fuel engine, characterized by, The method using the buffer tank pressure control system for an alcohol-hydrogen fuel engine according to any one of claims 1-6 comprises the following steps: starting the engine in the gasoline fuel mode, and preheating the reformer by using the heat generated by gasoline combustion; when the pressure and temperature of the reformer reach the preset reaction conditions, switching to the alcohol-hydrogen fuel mode; in the alcohol-hydrogen fuel mode, collecting the pressure and temperature signals of the reformer and the buffer tank in real time by the measuring unit, and inputting these signals into the processing unit; the fuzzy controller in the processing unit performs fuzzy reasoning according to the input pressure, temperature and pressure change rate, and outputs the duty cycle of the PWM signal by using the preset fuzzy rules; the execution unit controls the opening time of the high-speed electromagnetic valve according to the duty cycle, so as to adjust the amount of ethanol entering the reformer, and realizes the accurate control of the pressure of the buffer tank; 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 according to the pressure value.

8. The method for controlling the pressure of the buffer tank of an alcohol-hydrogen fuel engine according to claim 7, wherein if the pressure of the buffer tank is lower than the preset pressure range, the alcohol-hydrogen fuel mode is exited, the fuel supply is switched to the gasoline fuel mode, and the alcohol-hydrogen fuel mode is entered again after the pressure and temperature meet the conditions; if the pressure of the buffer tank is within the preset pressure range, the alcohol-hydrogen fuel mode is continuously maintained. If the pressure of the buffer tank is higher than the preset pressure range, the safety valve is opened, and the alcohol hydrogen fuel mode is still used. 9.A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method for buffer tank pressure control of an alcohol hydrogen fuel engine according to claim 7 or 8. 10.A computer device comprising a processor and a memory, wherein the memory has stored thereon a computer program, and the processor implements the method for buffer tank pressure control of an alcohol hydrogen fuel engine according to claim 7 or 8 when executing the computer program.

Images