A control method for an aero-engine acceleration state braking system

Abstract

The application belongs to the field of brake system control, and is an aero-engine acceleration state brake system control method. Key parameters of engine acceleration process control are selected first, each key parameter is provided with a target limit value, and a deviation threshold is set between each key parameter and the corresponding target limit value. When the deviation of engine acceleration process control exceeds the deviation threshold, the acceleration state is exited. At this time, the control value obtained by the acceleration fuel supply exit PID regulation is controlled, the brake oil amount is obtained, and the brake control is switched. The deviation threshold is set to realize the switching between the engine acceleration process control and the brake control, to realize that the engine acceleration state fuel supply PID regulator meets the acceleration requirement, and to realize the requirement of rapid braking when the acceleration state is exited, so as to avoid engine over-temperature, over-speed and over-pressure, thereby solving the shortcoming that the acceleration fuel supply PID regulator cannot be compatible with acceleration and over-regulation limitation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of brake system control, and particularly relates to an aero-engine acceleration state brake system control method. BACKGROUND

[0002] When the aircraft throttle lever is stepped up, the engine will increase the fuel flow according to the pre-set fuel supply law until the engine reaches the expected speed in order to reach the target state corresponding to the throttle lever position. The user has quantitative technical index requirements for engine acceleration, in order to meet the requirement that the engine speed rising rate reaches the user specified time, a good acceleration rate line is expected, and it is expected to exit acceleration when approaching the target speed state, but exiting acceleration when approaching the target speed state will cause over-speed, over-temperature and over-pressure due to excessive acceleration fuel supply; in severe cases, engine over-speed, over-temperature and over-pressure alarms are triggered.

[0003] Currently, after the engine enters the acceleration working state, the control system uses a PID regulator to control the fuel supply according to the target speed corresponding to the throttle lever; at the same time, a fuel supply limit line needs to be developed according to the remaining stability margin of the engine in the acceleration working state.

[0004] When the current engine enters the acceleration working state, the acceleration is good in the early stage of acceleration, and in the later stage of acceleration, in order to avoid speed and temperature and pressure overshoot due to excessive fuel quantity when approaching the target speed, the control parameters of the PID regulator need to be adjusted to reduce the fuel supply increment rising rate, but at the same time the acceleration is lost.

[0005] It is difficult to have a set of control parameters that can meet the engine overshoot requirement and acceleration requirement in engineering applications, especially when the engine is used as an industrial product, the performance has dispersion, and at the same time, the performance will also show a trend of attenuation with the accumulation of service life. The control system parameters cannot be compatible with the above performance differences and meet the overshoot requirement and acceleration requirement.

[0006] Therefore, how to simultaneously meet the overshoot requirement and acceleration requirement of the PID regulator is a problem to be solved. SUMMARY

[0007] The purpose of the present application is to provide an aero-engine acceleration state brake system control method to solve the problem that the PID regulator is difficult to simultaneously meet the overshoot requirement and acceleration requirement in the prior art.

[0008] The technical solution of the present application is: an aero-engine acceleration state brake system control method, comprising:

[0009] The key parameters of engine acceleration process control are selected, including speed n, temperature Tg and compressor rear pressure P3, and each key parameter is correspondingly provided with a target limit value, including speed target value ndem , temperature target value Tg dem , pressure target value P3 after compressor dem ; deviation threshold is set for the deviation between each key parameter and corresponding target limit value, and then engine acceleration process control is carried out by PID regulator oil supply;

[0010] When the deviation of engine acceleration process control exceeds the deviation threshold, the acceleration state is exited; at this time, the control value obtained by the PID regulation is exited for acceleration oil supply, the braking oil amount is obtained and switched to braking control;

[0011] After engine braking M cycles are controlled by the braking oil amount, the braking oil amount control is exited and the PID regulator oil supply control is restored.

[0012] Preferably, the braking oil amount Wzd obtaining method is:

[0013] Engine acceleration process control is carried out by PID regulator oil supply, and the data of high-pressure rotor conversion speed and conversion oil-gas ratio are collected until the exit acceleration moment;

[0014] The acceleration moment high-pressure rotor conversion speed n 2R-tcjs of the engine at the exit acceleration moment is obtained. 2R-tcjs , and the acceleration moment pressure P3 after the compressor -tcjs ;

[0015] The exit acceleration moment high-pressure rotor conversion speed n 2R-tcjs is obtained by interpolation according to the acceleration moment high-pressure rotor conversion speed n 2R-tcjs and the acceleration moment pressure P3 after the compressor P3 -tcjs . 2R-tcjs The corresponding conversion oil-gas ratio (W ZD / P3) R ; the braking oil amount at the next moment is calculated.

[0016] Preferably, the calculation formula of the braking oil amount at the next moment is:

[0017] W ZD =(W ZD / P3) R *P3 -tcjs *k*(T1 / 288.15)^ α

[0018] In the formula, T1 is the atmospheric temperature at the time; α is the temperature conversion index; k is the reserved oil supply correction coefficient.

[0019] Preferably, the relationship between the high-pressure rotor conversion speed and the conversion oil-gas ratio is expressed in the form of a number table.

[0020] Preferably, the deviation threshold is set as:

[0021] 1) When n dem -n < A%, and the duration is greater than or equal to N control cycles;

[0022] 2) When T g dem -T g <B℃, and the duration is greater than or equal to N control cycles;

[0023] 3) When P3 dem -P3 < CkPa, and the duration is greater than or equal to N control cycles.

[0024] Preferably, the specific values of A, B and C are determined by collecting parameters through experiments, and N is set according to experience.

[0025] The aero-engine acceleration state braking system control method provided by the application realizes the switching between the engine acceleration process control and the braking control by setting the deviation threshold, realizes that the oil supply PID regulator in the engine acceleration state meets the acceleration requirement, and realizes the requirement of rapid braking when the acceleration state exits, thereby avoiding the engine over-temperature, over-speed and over-pressure, and solving the shortcoming that the acceleration oil supply PID regulator cannot be compatible with acceleration and over-regulation limitation. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions provided by the application, the following will briefly introduce the drawings. Obviously, the drawings described below are only some embodiments of the application.

[0027] Figure 1 It is a schematic diagram of the overall process of the application;

[0028] Figure 2 It is a scatter plot of the high-pressure rotor conversion speed and oil-gas ratio relationship of the application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0030] An aero-engine acceleration state braking system control method, as shown in Figure 1 , comprising the following steps:

[0031] Step S100, setting the acceleration process exit control condition

[0032] The key parameters for engine acceleration process control mainly include engine speed n, temperature Tg, and compressor afterpressure P3. Each key parameter has a corresponding target limit value, including the target engine speed n. dem Target temperature value Tg dem Target pressure value P3 after compressor dem .

[0033] Set deviation thresholds for the deviations between each key parameter and its corresponding target limit, specifically as follows:

[0034] 1) When n satisfies dem -n < A%, and the duration is greater than or equal to N control cycles;

[0035] 2) When T is satisfied g dem –T g <B℃, and the duration is greater than or equal to N control cycles;

[0036] 3) When P3 is satisfied dem –P3 < CkPa, and the duration is greater than or equal to N control cycles.

[0037] A, B, and C can be selected or added according to the specific characteristics of the controlled object; the specific values ​​of A, B, and C are determined through experimental parameter collection and then statistical analysis, while N is set based on experience. Increasing the deviation threshold affects the timing of exiting acceleration control earlier, while decreasing the deviation threshold delays the timing of exiting acceleration control. Setting N judgment cycles is to avoid misjudgments caused by parameter disturbances.

[0038] After the deviation threshold is set, the engine acceleration process is controlled by fuel supplied by a PID controller.

[0039] Step S200: When the deviation of the engine acceleration process control exceeds the deviation threshold, exit the acceleration state; at this time, control the acceleration fuel supply to exit the control value obtained by PID regulation, obtain the brake fluid quantity and switch to brake control. The brake fluid quantity symbol is defined as Wzd, and the unit is kg / hour.

[0040] The method for obtaining brake fluid level Wzd is as follows:

[0041] Step S210: Perform engine acceleration process control using a PID controller for fuel supply, collecting data on the high-pressure rotor's converted speed and the converted air-fuel ratio until the acceleration phase ends. The engine operates at the same high-pressure rotor converted speed (n... 2R If the nozzle area is constant, then the converted oil-gas ratio (W) ZD / P3) R It is also certain; the converted air-fuel ratio generally refers to the ratio of the amount of fuel supplied to the engine's combustion chamber to the total pressure after the compressor. For example... Figure 2As shown, it shows the oil-gas ratio corresponding to different conversion speeds under different height and Mach number conditions. In order to facilitate control, the relationship between the high-pressure rotor conversion speed and the conversion oil-gas ratio is expressed in the form of a numerical table, so as to facilitate subsequent calculation. The numerical table format is shown in the following table:

[0042] n 2R (%)]] … … … … … … … … (W ZD / P3) R ]]> … … … … … … … …

[0043] Step S220, obtaining the engine acceleration time high-pressure rotor conversion speed n 2R-tcjs and the acceleration time compressor rear pressure P3 -tcjs .

[0044] Step S230, according to the acceleration time high-pressure rotor conversion speed n 2R-tcjs and the acceleration time compressor rear pressure P3 -tcjs interpolation to obtain the exit acceleration time high-pressure rotor conversion speed n 2R-tcjs corresponding conversion oil-gas ratio (W ZD / P3) R ;

[0045] Step S240, calculating the brake oil amount at the next time, the brake oil amount corresponding to the next time after the exit acceleration time is:

[0046] W ZD =(W ZD / P3) R *P3 -tcjs *k*(T1 / 288.15)^ α

[0047] In the formula: T1 is the atmospheric temperature at the time (unit: K), which is the data for engine test; α is the temperature conversion index, which is obtained according to the engine temperature performance influence test; k is the reserved oil supply correction coefficient, which is recommended to be less than 1, to obtain lower brake oil amount.

[0048] Step S300, controlling the engine brake through the brake oil amount for M cycles, until the speed acceleration action is completed, the brake oil amount control is exited, and the PID regulator oil supply control is restored. Since the engine speed deviation from the target speed is small at this time, the engine can smoothly transition to the steady-state control of the target speed.

[0049] In summary, the application realizes the switching between engine acceleration process control and brake control by setting a deviation threshold, realizes that the engine acceleration state oil supply PID regulator meets the acceleration requirement, and at the same time realizes the requirement of rapid braking when the acceleration state exits, avoids engine over-temperature, over-speed and over-pressure, and solves the shortcomings that the acceleration oil supply PID regulator cannot be compatible with acceleration and overshoot limitation.

[0050] Finally, it needs to be explained that: the present application discloses the embodiment in the drawing, only relates to the structure involved in the present application, other structures can refer to the usual design, under the condition of not conflicting, the same embodiment and different embodiments of the present application can be combined with each other;

[0051] Finally: the above only for the preferred embodiment of the present application, and not for limiting the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. An aircraft engine acceleration state brake system control method, characterized by, The method comprises the following steps: Key parameters of the engine acceleration process control are selected, including the rotation speed n, the temperature Tg, and the compressor rear pressure P3, each of which is provided with a target limit value, including the rotation speed target value n dem , the temperature target value Tg dem , and the compressor rear pressure target value P3 dem ; a deviation threshold value is set for the deviation between each key parameter and the corresponding target limit value, and then the engine acceleration process control is performed by the PID regulator oil supply. When the deviation of the engine acceleration process control exceeds a deviation threshold, the acceleration state is exited; at this time, the control value obtained by exiting the PID regulation of the acceleration fuel supply is controlled, the braking oil amount is obtained, and the braking control is switched to; After the engine braking is controlled by the braking oil amount for M cycles until the end of the speed acceleration action, the braking oil amount control is exited, and the PID regulator fuel supply control is restored; The amount of brake oil W ZD The acquisition method is: The engine acceleration process control with the PID regulator fuel supply is performed, the data of the high-pressure rotor converted speed and the converted oil-gas ratio are collected, and the process is continued until the exit of the acceleration; The engine acceleration time high-pressure rotor conversion speed n at the exit acceleration time 2R-tcjs The compressor rear pressure P3 at the acceleration time -tcjs ; According to the high-pressure rotor conversion speed n at the acceleration time 2R-tcjs With the compressor rear pressure P3 at the acceleration time -tcjs Interpolation to obtain the high-pressure rotor conversion speed n at the exit acceleration time 2R-tcjs The corresponding conversion oil-gas ratio (φ) W ZD / P 3) R ; The braking oil amount of the next moment is calculated; The calculation formula of the braking oil amount of the next moment is: W ZD W ZD P 3) R *P3 -tcjs *k*( T 1 / 288.15 α ​​ In the formula: T 1 is the temperature of the atmosphere at the time; α is the index of temperature conversion; and k is the correction coefficient for the amount of oil reserved.

2. The control method of claim 1, wherein: The relationship between the high-pressure rotor converted speed and the converted oil-gas ratio is expressed in the form of a numerical table.

3. The control method of claim 1, wherein, The deviation threshold is set as: 1) when n dem - n <A% and the duration is greater than or equal to N control cycles; 2) when the following conditions are met T g dem - T g B < T < B + C, and the duration is greater than or equal to N control cycles; 3) when the following are satisfied P 3 dem - P 3 < CkPa and the duration is greater than or equal to N control periods.

4. The control method of claim 3, wherein: The specific values of A, B and C are determined by collecting parameters through experiments and statistics, and N is set according to experience.

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