Alpha2 advance control method for a digital full authority engine control system

Abstract

The application belongs to the technical field of aero-engine control, and particularly relates to an alpha2 advance control method of a digital full-authorization engine control system, comprising the following steps: increasing an N2 re-adjusting amount to ensure that a backup advance mechanism can exit work when not in an alpha2 advance control state under electric-governor main control; setting an N2 re-adjusting electromagnetic valve working logic to synchronize a working time of the backup advance mechanism under the electric-governor main control with an alpha2 advance control state; and setting a delay fault judgment logic for an alpha2 control loop when the electric-governor main control enters and exits the alpha2 advance control. The control method can meet the requirement of partial-governor control when in the alpha2 advance control state under the electric-governor main control, and can avoid the interference of the alpha2 control by the backup advance mechanism when not in the alpha2 advance control state, and can consider the alpha2 control quality in a steady state / transient state under the electric-governor main control, and can solve the problem of alpha2 control loop fault caused by the interference of alpha2 by the backup system.

Description

Technical Field

[0001] This application belongs to the field of aero-engine control technology, and specifically relates to an α2 advance control method for a digital full authority engine control system. Background Technology

[0002] For a certain type of turbofan engine, in order to ensure surge margin during deceleration, it is necessary to control the compressor guide vane angle α2 in advance so that α2 is relatively off-center in steady state during deceleration.

[0003] The existing digital full authority engine control system with mechanical hydraulic backup is controlled by the digital electronic controller (hereinafter referred to as "electronic controller system") when the CNC system is normal, and makes precise adjustments according to the normal working state of the engine. This is called "electronic controller master control". When the CNC system fails, the mechanical hydraulic backup system (hereinafter referred to as "backup system") takes over the basic functions of the digital electronic controller to realize the control of the engine in a lower working state. This is called "backup master control".

[0004] I. Interference of the backup system on the α2 control of the ESC system

[0005] In existing control systems, the timing of α2 advance entry and exit is asynchronous between the ESC and backup systems. Furthermore, the α2 control of the ESC is limited by the backup system, making the α2 control during ESC master control susceptible to interference from the backup system. This will be discussed from two aspects below:

[0006] (a) Under the existing control system architecture, the conditions for entering α2 advance control are different for the main ESC and the backup main ESC.

[0007] Under ESC master control, the conditions for entering α2 lead control are:

[0008] N2-N2Dem_dt≥Δ2 (1)

[0009] Under ESC master control, the condition for exiting α2 lead control is:

[0010] N2-N2Dem_dt≤Δ4 (2)

[0011] Under the backup master controller, the conditions for entering α2 advanced control are:

[0012] N2-N2Dem_bf≥Δ3 (3)

[0013] Under the backup master controller, the conditions for exiting α2 advance control are:

[0014] N2-N2Dem_bf<Δ3 (4)

[0015] N2 is the high-pressure rotor speed (%). The electronic speed control system transmits the electrical signal collected by the magnetoresistive speed sensor to the digital electronic controller, while the backup system transmits the mechanical signal from the centrifugal speed sensor to the speed regulator in the main fuel pump regulator.

[0016] N2Dem_dt is the set value (%) of N2 when the ESC is in main control, which is set by the control software in the digital electronic controller;

[0017] N2Dem_bf is the set value (%) of N2 when the main controller is backed up, which is set by the mechanical structure inside the main fuel pump regulator.

[0018] In the existing system, Δ3≤Δ4<Δ2.

[0019] Under the main control of the electronic speed controller, the entry / exit conditions of α2 advance control are accurately determined by the digital electronic controller after direct calculation, and Δ2 and Δ4 are both fixed values; under the backup main control, the entry / exit conditions of α2 advance control are determined by the α2 advance mechanism of the main fuel pump regulator in the backup system (hereinafter referred to as "backup advance mechanism") based on mechanical signals, and Δ3 varies to some extent for different engines.

[0020] (ii) Under the existing control system architecture, the adjustment range of α2 under the main ESC is limited by the backup system.

[0021] Under the main control of the electronic speed controller, the controller calculates the duty cycle PWMα2 (adjustable range 0~100%) based on the deviation between α2 and the set value α2Dem, and sends it to the main fuel pump regulator α2 duty cycle solenoid valve to adjust the angle of α2. During the main control of the electronic speed controller, although the backup system's N2Dem_bf does not affect the adjustment of the main fuel, that is, it does not affect the actual adjustment of N2, the backup advance mechanism still enters or exits operation according to the conditions of equations (3)~(4).

[0022] α2Dem is a function of the converted speed N2r of the high-pressure rotor. Where T1 is the engine intake total temperature (in K). In this paper, the larger the α2 angle value, the more off-center the corresponding compressor guide vane angle.

[0023] 1) When the backup lead mechanism is not in operation, the limitations of the backup system on the adjustment range of the power control system are as follows: Figure 1 .

[0024] Figure 1 In the diagram, the solid line on the left represents the steady-state α2Dem under the main ESC control, and the solid line on the right represents the α2Dem during the α2 advance control process under the main ESC control. The area between the two dashed lines represents the adjustment range of the ESC system's α2 when the backup advance mechanism is not in operation.

[0025] 2) When the backup advance mechanism is put into operation, the limitations of the backup system on the adjustment range of the electronic control system are as follows: Figure 2 .

[0026] Figure 2 In the middle, the solid line has the same meaning as Figure 1 The area between the two dashed lines represents the adjustment range of the ESC system α2 when the backup advance mechanism is in operation.

[0027] 3) The impact of the backup advance mechanism being put into operation under the main control of the ESC on the control of ESC α2:

[0028] The relationship between the steady-state high-pressure rotor speed setpoint N2Dem (%) at the intake total temperature T1 (K) and the throttle lever angle PLA (°) is usually referred to as the "throttle characteristic".

[0029] N2Dem_dt=f1(T1, PLA) (5)

[0030] N2Dem_bf=f2(T1, PLA) (6)

[0031] Comparison of throttle characteristics between electronic speed control system and backup system, for example Figure 3 Under the same T1 and PLA conditions, the N2Dem_dt of the main ESC controller is higher than that of the backup main controller, and there is...

[0032] N2Dem_dt - N2Dem_bf>Δ3 (7)

[0033] Therefore, when the ESC system under the master control does not meet the conditions for entering α2 lead control, the backup lead mechanism is prone to activating. Figure 2 This situation will cause α2 to deviate from the ESC system setpoint α2Dem.

[0034] II. Measures to overcome interference from the backup lead mechanism to the α2 control of the electronic control system in the existing control system

[0035] To address the issue of α2 control in the aforementioned electronic control system being susceptible to interference from the backup system, the existing control system incorporates an N2 recalibration function for the backup system. The N2 recalibration function is achieved through the operating state of the "N2 recalibration solenoid valve" of the main fuel pump regulator: when the "N2 recalibration solenoid valve" is energized, N2 recalibration is performed, causing the N2 setpoint N2Dem_ct sensed by the backup lead mechanism (i.e., the N2 setpoint sensed by the backup lead mechanism when the recalibration solenoid valve is energized) to increase by a recalibration amount Δ compared to N2Dem_bf (e.g., ...). Figure 3 When the "N2 readjustment solenoid valve" is de-energized, N2 readjustment is not performed, and the N2 setpoint sensed by the backup advance mechanism remains N2Dem_bf. That is:

[0036] When the N2 readjustment solenoid valve is energized, the conditions for the backup advance mechanism to activate become as follows:

[0037] N2-N2Dem_ct≥Δ3

[0038] When the N2 readjustment solenoid valve is energized, the condition for the backup advance mechanism to disengage becomes:

[0039] N2-N2Dem_ct<Δ3

[0040] When the N2 readjustment solenoid valve is de-energized, the conditions for the backup advance mechanism to operate remain the same.

[0041] N2-N2Dem_bf≥Δ3

[0042] When the N2 readjustment solenoid valve is de-energized, the conditions for the backup advance mechanism to exit operation remain the same.

[0043] N2-N2Dem_bf<Δ3

[0044] In the formula, N2Dem_ct= N2Dem_bf+Δ

[0045] The operating state of the aforementioned main fuel pump regulator's "N2 readjustment solenoid valve" is set by a digital electronic controller sending commands according to a pre-defined operating logic. The operating logic of the existing control system's N2 readjustment solenoid valve is as follows: during main electronic control, the "N2 readjustment solenoid valve" is continuously energized, causing the N2 setpoint N2Dem_ct (the N2 setpoint sensed by the backup advance mechanism when the readjustment solenoid valve is energized) to increase by a readjustment amount Δ compared to N2Dem_bf (e.g., ...). Figure 3 When the main control is backed up, the "N2 readjustment solenoid valve" remains de-energized, and the α2 control function of the backup system remains unchanged.

[0046] It is important to emphasize that during ESC master control, the existing control system controls the high-pressure rotor speed N2 according to the algorithm set within the digital control electronics. The aforementioned N2 readjustment function adjusts the N2 setting value obtained by the backup advance mechanism through the mechanical hydraulic system, thereby adjusting the timing of the backup advance mechanism's activation, and does not affect the control of the high-pressure rotor speed N2 during ESC master control.

[0047] Depend on Figure 1 , Figure 2 To ensure that α2 follows the set value α2Dem under the ESC master control, in this scheme, on the one hand, the value of Δ cannot be too small; Δ should be greater than Δ3 to ensure that the backup lead mechanism of the ESC master control does not operate under steady state, thus ensuring that α2 of the ESC system has... Figure 1 Instead Figure 2 The adjustment range; on the other hand, Δ cannot be too large, so that the backup advance mechanism can be put into operation when the ESC enters the α2 advance control condition under the main control of the ESC in all operating states of the engine, so that α2 has Figure 2 Instead Figure 1The adjustment range. This requires:

[0048] N2Dem_ct<N2Dem_dt+Δ2

[0049] Also, N2Dem_ct = N2Dem_bf + Δ.

[0050] N2 readjustment amount Δ < N2Dem_dt - N2Dem_bf + Δ2;

[0051] The "throttle characteristics" of the ESC system and backup system introduced in the background technology section have...

[0052] N2Dem_dt=f1(T1, PLA)

[0053] N2Dem_bf=f2(T1, PLA)

[0054] Therefore, the N2 readjustment amount Δ should satisfy the following:

[0055] Δ<min[f1(T1,PLA)-f2(T1,PLA)]+ Δ2

[0056] Based on the above analysis, the range of the N2 readjustment amount Δ is set as follows:

[0057] Δ>Δ3 and Δ<min[f1(T1,PLA)-f2(T1,PLA)]+Δ2

[0058] In the formula, T1 and PLA cover all operating conditions of the engine. The specific value of the N2 readjustment can be achieved by adjusting the extension of the corresponding adjusting screw on the main fuel pump regulator.

[0059] The existing α2 control system architecture that has implemented the aforementioned N2 readjustment measures is as follows: Figure 4 The control system mainly consists of a digital electronic controller, a main fuel pump regulator, actuators, and sensors. The main fuel pump regulator sets the N2 readjustment amount, while the control software of the digital electronic controller controls the operating logic of the N2 readjustment solenoid valve.

[0060] In this architecture, the control software of the digital electronic controller determines the working command of the N2 readjustment solenoid valve of the main fuel pump regulator based on the main control status and the α2 advance control status, and calculates the duty cycle signal PWMα2 of the α2 duty cycle solenoid valve of the main fuel pump regulator based on the PID control algorithm. The architecture includes a main control judgment module, an α2 advance control judgment module and a PID control module.

[0061] The aforementioned main control judgment module can determine whether the electronic control system (ECS) is activated based on the operating mode of the digital electronic controller. The aforementioned α2 advance control judgment module can receive engine onboard parameters to determine whether the ECS system is in the α2 advance control state. The PID control module is used to receive the compressor guide vane angle α2 collected by the actuator sensor, determine the setting of N2 during ECS ​​main control and the setting value of N2 and the α2 setting value α2Dem during backup main control, and calculate the duty cycle signal PWMα2 output to the main fuel pump regulator α2 duty cycle solenoid valve.

[0062] The N2 readjustment amount is controlled by the main fuel pump regulator, which includes an N2 readjustment solenoid valve and an α2 duty cycle solenoid valve. The N2 readjustment solenoid valve is used to receive the working command of the digital electronic controller to perform N2 readjustment (powered on, readjustment is performed; de-powered, readjustment is not performed). The α2 duty cycle solenoid valve is used to receive the duty cycle signal PWMα2 of the digital electronic controller and adjust the pressure of the rod chamber and rodless chamber of the actuator.

[0063] III. Problems with Existing Control Systems

[0064] As mentioned above, existing control systems can overcome the interference of the backup lead mechanism on the ESC α2 control by addressing the following issues:

[0065] 1) It can prevent the backup lead mechanism from working in the steady state of the ESC main control, thus avoiding the backup system from interfering with the α2 control of the ESC system;

[0066] 2) Under the main control of the ESC, after the ESC system meets the conditions for entering α2 advance control, the backup advance mechanism can be put into operation, so that the α2 angle meets the requirements of the off-center control.

[0067] However, because the timing of the ESC system and the backup system entering / exiting α2 advance control is not synchronized, the following problems still exist:

[0068] 1) Under the main control of the ESC, during the process of slightly pulling down the throttle lever, the ESC system may not enter the α2 advance control and the backup advance mechanism may not be engaged, causing α2 to be off relative to the set value α2Dem, thus affecting the following performance of the ESC system α2.

[0069] 2) When the aforementioned situation occurs where the ESC system fails to engage α2 advance control and the backup advance mechanism is activated, due to limitations imposed by the backup system, α2 remains continuously off relative to the setpoint α2Dem, and the ESC system continuously adjusts α2 in the off direction. At the moment the backup advance mechanism disengages, both the ESC system and the backup system adjust α2 in the off direction, often resulting in α2 deviating excessively from the setpoint α2Dem, causing α2 control loop malfunctions. This increases the interpretation and maintenance work for ground personnel and affects aircraft sorties.

[0070] IV. Existing technical solutions related to this invention and their disadvantages

[0071] 1) The existing solution of adding speed N2 readjustment function solves the problem that the ESC does not advance in steady state but the backup advances in. However, before the ESC advances in α2, it is necessary to use the backup system to advance in (the backup advance mechanism is put into operation) to meet the requirements of α2 off control. The current speed N2 readjustment amount must ensure that the backup system does not advance in steady state (i.e., the readjustment amount cannot be too large), and also ensure that the backup system can advance in the process of the ESC advancing in (i.e., the readjustment amount cannot be too small).

[0072] The existing speed regulation effectively balances the above two aspects and can achieve steady-state backup α2 without advance. However, during the transition process of throttle pull-down, due to the asynchronous entry / exit of the backup and ESC advance, sometimes α2 deviates from the setpoint due to interference from the backup system under the ESC main control, causing the α2 control loop to malfunction.

[0073] 2) To address the issues with the throttle transition state in the above-mentioned scheme, an algorithm can be designed to identify the backup-in-advance and non-advance modes using existing engine onboard parameters. On one hand, identifying this mode can delay fault reporting, reducing α2 control loop fault reports caused by interference from the backup system to the ESC system, thus reducing user interpretation and maintenance work. On the other hand, identifying this mode allows for timely adjustment of the α2 control loop parameters, minimizing interference from the backup-in-advance mechanism on α2 control and improving α2's tracking performance.

[0074] However, this method does not substantially solve the problem of mismatch between the ESC / backup system and cannot avoid interference from the backup lead mechanism on the control of ESC α2.

[0075] 3) The scheme of separate design of electronic control / backup α2 control oil circuit can avoid the interference of backup system to electronic control system α2 control, but this requires changing the existing control system architecture and redesigning the main fuel pump regulator. The changes are large, the development and verification costs are high, and the cycle is long.

[0076] Therefore, how to achieve more effective advanced control of a digital full authority engine control system with mechanical and hydraulic backup with a shorter development cycle and lower economic cost is a problem that needs to be solved. Summary of the Invention

[0077] To address the aforementioned issues, this application provides an α2 advance control method for a digital full authority engine control system, which solves the problem of poor α2 tracking and easy failure caused by interference from the backup advance mechanism during the main control of the electronic speed controller in the existing system architecture.

[0078] The technical solution of this application is: an α2 advance control method for a digital full authority engine control system, comprising:

[0079] The method for setting the N2 readjustment amount is as follows: By increasing the N2 readjustment amount of the main fuel pump regulator, it is ensured that when the engine is not in α2 lead control state under the electronic speed controller (ESC), the energization of the N2 readjustment solenoid valve can disengage the backup lead mechanism. This requires that, in this situation, the readjusted speed N2 setpoint sensed by the backup lead mechanism is higher than the speed N2 threshold that causes the ESC system to enter α2 lead control, i.e., N2Dem_ct > N2Dem_dt + Δ2.

[0080] If the aforementioned N2 readjustment setting allows N2Dem_ct > N2Dem_dt + Δ2 to hold true, then according to N2Dem_dt - N2Dem_bf > Δ3, when the engine is in α2 advance control state under the electronic speed controller, N2Dem_ct > N2Dem_bf + Δ2 + Δ3, thus N2 - N2Dem_bf ≥ Δ3 must hold true. That is, in this case, if the N2 readjustment solenoid valve is de-energized, it ensures that the backup advance mechanism disengages.

[0081] By setting an appropriate N2 readjustment amount, under the control of the electronic speed controller, the following can be achieved: when the engine is not in the α2 advance control state, energizing the N2 readjustment solenoid valve can disengage the backup advance mechanism; when the engine is in the α2 advance control state, de-energizing the N2 readjustment solenoid valve can disengage the backup advance mechanism.

[0082] The operating logic of the N2 readjustment solenoid valve is configured as follows: By adjusting the energizing / de-energizing conditions of the N2 readjustment solenoid valve, the timing of the backup advance mechanism's engagement / disengagement under the ESC main control is synchronized with the timing of the α2 advance control state's entry / exit. This operating logic ensures that, under the aforementioned N2 readjustment values, the operating timing of the backup advance mechanism is synchronized with the ESC system's α2 advance control state.

[0083] Set the delay fault diagnosis logic for the α2 control loop: within the first time threshold after the ESC α2 advance control state entry condition is met, do not judge the α2 control loop fault; within the second time threshold after the ESC α2 advance control state exit condition is met, do not judge the α2 control loop fault.

[0084] Improvements were made to the α2 advance control system: This control system mainly consists of a digital electronic controller, a main fuel pump regulator, actuators, and sensors. Specifically, the main fuel pump regulator sets the aforementioned N2 readjustment amount, and the control software of the digital electronic controller implements the operating logic of the aforementioned N2 readjustment solenoid valve and sets the delay fault-detection logic for the α2 control loop.

[0085] Preferably, the value of the N2 readjustment amount Δ should satisfy:

[0086] Δ>max[f1(T1,PLA)-f2(T1,PLA)]+Δ2 and Δ≤Δ_JXmax

[0087] The numerical range of the N2 readjustment Δ setting can be derived as follows:

[0088] To ensure that the backup advance mechanism does not engage when the N2 readjustment solenoid valve is energized under the main control of the electronic speed controller (ESC), the readjusted engine speed N2 under the ESC's main control must be higher than the speed N2 required to trigger the ESC to enter α2 advance control in all engine operating states.

[0089] N2Dem_ct>N2Dem_dt+Δ2;

[0090] Also, N2Dem_ct = N2Dem_bf + Δ.

[0091] N2 readjustment Δ>N2Dem_dt-N2Dem_bf+Δ2;

[0092] The "throttle characteristics" of the ESC system and backup system introduced in the background technology section have...

[0093] N2Dem_dt=f1(T1, PLA)

[0094] N2Dem_bf=f2(T1, PLA)

[0095] Therefore, the N2 readjustment amount Δ should satisfy the following:

[0096] Δ>max[f1(T1,PLA)-f2(T1,PLA)]+ Δ2

[0097] Due to the hardware limitations of the main fuel pump regulator, it is also necessary to meet the following requirements.

[0098] Δ≤Δ_JXmax,

[0099] That is, the set range of N2 readjustment Δ values ​​is:

[0100] Δ>max[f1(T1,PLA)-f2(T1,PLA)]+Δ2 and Δ≤Δ_JXmax

[0101] In the formula, Δ represents the N2 readjustment amount, Δ2 is a constant value, N2Dem_ct is the N2 setpoint sensed by the backup advance mechanism when the readjustment solenoid valve is energized, N2Dem_dt is the N2 setpoint when the electronic speed controller is in main control, N2Dem_bf is the N2 setpoint when the backup main control is in main control, Δ_JXmax is the maximum N2 readjustment amount under the limitations of the existing mechanical structure of the main fuel pump regulator, T1 is the intake air total temperature, and PLA is the throttle lever angle. The ranges of T1 and PLA should encompass all operating conditions of the engine.

[0102] In the existing control system, the adjustment space of the main fuel pump regulator N2 readjustment amount is sufficient, that is, Δ_JXmax is large enough. Without changing the materials and structure of the internal components of the main fuel pump regulator, only the extension of the internal adjusting screw is adjusted (without changing the outer contour of the main fuel pump regulator), satisfying Δ>max[f1(T1,PLA)-f2(T1,PLA)]+ Δ2, so as to achieve the design value of N2 readjustment amount in this scheme with a small modification.

[0103] Preferably, the working logic of the N2 readjustment solenoid valve is as follows: when the ESC is in main control and the engine is in α2 advance control state, the N2 readjustment solenoid valve is de-energized; when the ESC is in main control and the engine is not in α2 advance control state, the N2 readjustment solenoid valve is energized; when the backup main control is in operation, the N2 readjustment solenoid valve is de-energized.

[0104] Preferably, the first time threshold is 0.1s (adjustable range 0.1s to 3s), and the second time threshold is 0.5s (adjustable range 0.1s to 5s).

[0105] Preferably, in the improved α2 advance control system, the digital electronic controller determines the N2 readjustment solenoid valve working command output to the main fuel pump regulator based on the main control state and the α2 advance control state, and calculates the duty cycle signal PWMα2 output to the α2 duty cycle solenoid valve of the main fuel pump regulator based on the PID control algorithm, including a main control judgment module, an advance control judgment module and a PID control module.

[0106] The main control judgment module can determine whether the electronic control system (ECS) is activated based on the operating mode of the digital electronic controller. The advanced control judgment module can receive engine onboard parameters to determine whether the ECS is in the α2 advanced control state. The PID control module is used to receive the compressor guide vane angle α2 collected by the actuator sensor, determine the set value of N2 and the set value of α2 α2Dem when the ECS is in operation, and calculate the duty cycle signal PWMα2 output to the main fuel pump regulator α2 duty cycle solenoid valve.

[0107] Preferably, in the improved α2 advance control system, the N2 readjustment amount control is performed by the main fuel pump regulator. The main fuel pump regulator includes an N2 readjustment solenoid valve and an α2 duty cycle solenoid valve. The N2 readjustment solenoid valve is used to receive the working command of the digital electronic controller to perform N2 readjustment control. The α2 duty cycle solenoid valve is used to receive the duty cycle signal PWMα2 of the digital electronic controller to adjust the rod chamber of the actuator and the rod chamber pressure.

[0108] The α2 advance control method of the digital full authority engine control system of this application has the following advantages:

[0109] In both steady-state and transient states under ESC master control, the backup lead mechanism and the ESC α2 lead can be synchronized to meet the conditions for entering / exiting α2 lead control. This not only satisfies the requirements of off-center control during ESC master control but also avoids interference from the backup lead mechanism during α2 lead control when not in α2 lead control. Therefore, it can better balance the α2 control quality under ESC master control in both steady-state and transient states, as well as in and out of α2 lead control processes. This method can be implemented on existing control systems with minor modifications, resulting in a short improvement cycle and low cost. Attached Figure Description

[0110] Figure 1 This is a schematic diagram of the α2 adjustment range when the backup advance mechanism of the main electronic control unit in the background technology is not in operation;

[0111] Figure 2 This is a schematic diagram of the α2 adjustment range when the backup advance mechanism of the main electronic control unit in the background technology is put into operation;

[0112] Figure 3 This is a schematic diagram of the electronic speed control / backup throttle characteristics and the readjusted throttle characteristics under the same intake air temperature T1 in the background technology.

[0113] Figure 4 This is a schematic diagram of the existing α2 control advanced control system architecture in the background technology;

[0114] Figure 5 This is a schematic diagram of the α2 advanced control system architecture of this application. Detailed Implementation

[0115] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only a part of the embodiments of this application, not all of them. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0116] This application provides an α2 advance control method for a digital full-authority engine control system, which solves the problem that in the existing control system architecture, during the transition process of throttle pull-down, the backup system and the electronic speed controller (ESC) system are not synchronized when entering / exiting α2 advance control. Sometimes, under the main control of the ESC, poor α2 control quality occurs due to interference from the backup advance mechanism, and sometimes the α2 control loop even malfunctions due to deviation from the setpoint. The method includes the following steps:

[0117] Step S100: Set the N2 readjustment amount. By increasing the N2 readjustment amount, ensure that the readjusted speed N2 setpoint sensed by the backup advance mechanism is higher than the speed N2 required for the ESC system to enter α2 advance control. This prevents the backup advance mechanism from operating when the N2 readjustment solenoid valve is energized under the ESC main control. Here, N2 is the high-pressure rotor speed, and α2 is the compressor guide vane angle.

[0118] Preferably, the value of the N2 readjustment amount Δ should satisfy:

[0119] Δ>max[f1(T1,PLA)-f2(T1,PLA)]+ Δ2 and Δ≤Δ_JXmax

[0120] The range of the N2 readjustment amount Δ mentioned above is determined according to the following process:

[0121] 1) Based on the condition that the high-voltage rotor speed N2 under the main control of the ESC enters α2 advance control in the existing control system, the deviation between the high-voltage rotor speed N2 and the high-voltage rotor speed setpoint N2Dem_dt is N2-N2Dem_dt≥Δ2, determine the speed deviation threshold Δ2.

[0122] 2) Based on the existing control system engine's electronic speed control throttle characteristics, determine the relationship between the steady-state high-pressure rotor speed setpoint N2Dem_dt under electronic speed control and the intake air total temperature T1 and throttle lever angle PLA, i.e., N2Dem_dt=f1(T1, PLA).

[0123] 3) Based on the backup throttle characteristics of the engine in the existing control system, determine the relationship between the steady-state high-pressure rotor speed setpoint N2Dem_dt under the electronic speed controller and the intake total temperature T1 and the throttle lever angle PLA, i.e., N2Dem_bf=f2(T1, PLA);

[0124] 4) Determine the ranges of T1 and PLA in steps 2) and 3) above, based on the temperature range of the engine's operating environment and the throttle lever angle range under operating conditions;

[0125] 5) Based on the relationships in 2) and 3) above, and the ranges of T1 and PLA in 4), find the maximum value of the speed deviation between the existing control system's electronic throttle characteristic and the backup throttle characteristic, i.e., max[f1(T1, PLA)-f2(T1, PLA)];

[0126] 6) Based on the adjustment range of the main fuel pump regulator N2 readjustment in the existing control system, determine the maximum value Δ_JXmax of the N2 readjustment under the constraints of the existing mechanical structure;

[0127] 7) Based on 5) and 6) above, the range for selecting the N2 readjustment amount Δ is determined as follows:

[0128] Δ>max[f1(T1,PLA)-f2(T1,PLA)]+ Δ2 and Δ≤Δ_JXmax

[0129] In the formula, Δ is the N2 readjustment amount, Δ2 is a constant value (Formula (5) in the background section), N2Dem_ct is the N2 set value sensed by the backup advance mechanism when the readjustment solenoid valve is energized, N2Dem_dt is the N2 set value when the electronic speed controller is in main control, N2Dem_bf is the N2 set value when the backup main control is in main control, Δ_JXmax is the maximum value of N2 readjustment amount under the existing mechanical structure limitation of the main fuel pump regulator, T1 is the intake air total temperature, and PLA is the throttle lever angle. In the formula, the range of T1 and PLA should cover all operating conditions of the engine.

[0130] Step S200: Set the operating logic of the N2 readjustment solenoid valve. When the ESC is in master control and the engine is in α2 advance control state, the N2 readjustment solenoid valve is de-energized; when the ESC is in master control and the engine is not in α2 advance control state, the N2 readjustment solenoid valve is energized; when the backup master control is in operation, the N2 readjustment solenoid valve is de-energized. Determine the timing for the backup advance mechanism to engage / disengage under ESC master control.

[0131] Preferably, the conditions for entering / exiting α2 lead control in the control software of the digital electronic controller are the same as those in the existing control system: under the electronically controlled master controller, the condition for entering α2 lead control is N2 - N2Dem_dt ≥ Δ2; under the electronically controlled master controller, the condition for exiting α2 lead control is N2 - N2Dem_dt ≤ Δ4. Where Δ2 and Δ4 are both constant values, and Δ4 < Δ2.

[0132] Step S300: When the ESC main controller enters and exits α2 advance control, a delay fault judgment logic is set for the α2 control loop.

[0133] The aforementioned design of the main fuel pump regulator N2 readjustment amount and the N2 readjustment solenoid valve's working logic ensures that, under the main control of the electronic speed controller (ESC), the backup advance mechanism and the ESC α2 advance mechanism are synchronized to meet the conditions for entering / exiting α2 advance control. However, because the backup advance mechanism requires a certain amount of time for the mechanical structure to move into position before it can engage, the actual backup advance mechanism lags slightly behind the ESC α2 setpoint during the entry / exit process.

[0134] To avoid the above process from causing short-term interference to the α2 control, and to prevent the α2 control loop from malfunctioning due to a short-term deviation of the α2 feedback value from its setpoint, a delayed fault-determination logic needs to be set. After the α2 advance entry / exit conditions are met, i.e., after the N2 re-adjustment solenoid valve is de-energized / re-energized for a period of time, the α2 control loop will not be judged as faulty.

[0135] Specifically: within the first time threshold after the conditions for entering the α2 advanced control state of the electronic speed controller are met, the fault of the α2 control loop is not judged; within the second time threshold after the conditions for exiting the α2 advanced control state of the electronic speed controller are met, the fault of the α2 control loop is not judged.

[0136] Preferably, the first time threshold is 0.1s (adjustable range 0.1s to 3s), and the second time threshold is 0.5s (adjustable range 0.1s to 5s). The aforementioned time thresholds can be adjusted based on the analysis of the motion characteristics of the backup advance mechanism according to the mechanical structure parameters, or based on the statistical analysis of the entry / exit time of the backup advance mechanism according to the data of the existing control system.

[0137] Step S400: Complete the improvement of the α2 advanced control system, such as... Figure 5 The control system mainly consists of a digital electronic controller, a main fuel pump regulator, actuators, and sensors. The N2 readjustment amount set in step S200, implemented by the main fuel pump regulator, can be achieved by adjusting the extension of the adjusting screw inside the main fuel pump regulator (without affecting the external dimensions of the main fuel pump regulator). The working logic of the N2 readjustment solenoid valve in step S200 and the delay fault-detection logic for the α2 control loop in step S300, implemented by the digital electronic controller, can be achieved by modifying the control software of the digital electronic controller. Thus, the working state of the backup advance mechanism is synchronized with the α2 advance control state of the electronic control system.

[0138] The improved α2 advance control system operates as follows:

[0139] The digital electronic controller determines the N2 readjustment solenoid valve operating command to the main fuel pump regulator based on the main control status and α2 advance control status, and calculates the duty cycle signal PWMα2 to be output to the α2 duty cycle solenoid valve of the main fuel pump regulator based on the PID control algorithm. It includes a main control judgment module, an advance control judgment module and a PID control module.

[0140] The main control judgment module can determine whether the electronic control system (ECS) is activated based on the operating mode of the digital electronic controller. The advanced control judgment module can receive engine onboard parameters to determine whether the ECS is in the α2 advanced control state. The PID control module is used to receive the compressor guide vane angle α2 collected by the actuator sensor, determine the setting of N2 during ECS ​​and the setting value of N2 and α2 set value α2Dem during backup ECS, and calculate the duty cycle signal PWMα2 output to the main fuel pump regulator α2 duty cycle solenoid valve.

[0141] The N2 readjustment amount is controlled by the main fuel pump regulator. The main fuel pump regulator includes an N2 readjustment solenoid valve and an α2 duty cycle solenoid valve. The N2 readjustment solenoid valve is used to receive the working command of the digital electronic controller to perform N2 readjustment (energized, readjustment is performed; de-energized, readjustment is not performed); the α2 duty cycle solenoid valve is used to receive the duty cycle signal PWMα2 from the digital electronic controller to adjust the pressure of the rod chamber and rodless chamber of the actuator.

[0142] In summary, this application has the following advantages:

[0143] 1) In both steady-state and transient states under the ESC master control, the backup lead mechanism and the ESC α2 lead can be synchronized to meet the conditions for entering / exiting α2 lead control. This can satisfy the requirements of off-center control during the ESC master control α2 lead control process, and avoid interference from the backup lead mechanism when the ESC is not in the α2 lead control process. This better balances the α2 control quality under the ESC master control in steady-state / transient state and when in / out of the α2 lead control process.

[0144] 2) Instead of shielding the α2 control loop from fault reports and adjusting control parameters to overcome the interference of the backup advance mechanism when the α2 control is identified as being interfered with by the backup system, it can achieve synchronous entry and exit of the α2 advance mechanism by the ESC / backup system, fundamentally avoiding interference from the backup advance mechanism with the control of α2 under the ESC master control: because the timing of the backup advance mechanism's entry into operation is controllable, the entry / exit process of the advance mechanism can be accurately determined without complex pattern recognition algorithms, thereby setting targeted delay fault judgment logic to avoid α2 control loop fault reports during the transition process; because it is not interfered with by the backup advance mechanism, there is no need to tune the control parameters for the identified special modes, which can improve the control quality of the α2 control loop during the transition process.

[0145] 3) The modifications are minimal, involving only changes to the digital electronic controller software and adjustments to the extension of the internal adjusting screw of the main fuel pump regulator (without affecting the external dimensions of the main fuel pump regulator). No hardware changes are required in terms of structure or materials, resulting in a short improvement cycle and low cost. For existing control system products, the design of this application can be implemented without re-fabricating the hardware.

[0146] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An α2 advance control method for a digital full-authority engine control system, characterized in that, include: Increase the N2 readjustment amount so that when the ESC main control is not in the α2 lead control state, the readjusted speed N2 setpoint obtained by the backup lead mechanism is higher than the speed N2 threshold that makes the ESC system enter the α2 lead control; where N2 is the high-pressure rotor speed and α2 is the compressor guide vane angle. Configure the N2 readjustment solenoid valve's operating logic to synchronize with the timing of entering / exiting the α2 advanced control state; A delayed fault detection logic is set for the α2 control loop. Within the first time threshold after the condition for entering the α2 advanced control state is met, the fault of the α2 control loop is not detected; within the second time threshold after the condition for exiting the α2 advanced control state is met, the fault of the α2 control loop is not detected. Based on the N2 readjustment amount, the working logic of the N2 readjustment solenoid valve, and the delay fault judgment logic of the α2 control loop, the α2 advance control system is improved, thus forming a new α2 advance control system architecture.

2. The α2 advance control method for a digital full-authority engine control system as described in claim 1, characterized in that, The N2 readjustment amount satisfies: Δ>max[f1(T1,PLA)-f2(T1,PLA)]+ Δ2 and Δ≤Δ_JXmax Furthermore, the range of the aforementioned N2 readjustment amount Δ is determined according to the following process: 1) Based on the condition of the deviation between the high-voltage rotor speed N2 and the high-voltage rotor speed setpoint N2Dem_dt when the ESC system enters α2 advance control under the main control of the existing control system, i.e. N2-N2Dem_dt≥Δ2, determine the speed deviation threshold Δ2. 2) Based on the existing control system engine's electronic speed control throttle characteristics, determine the relationship between the steady-state high-pressure rotor speed setpoint N2Dem_dt under electronic speed control and the intake air total temperature T1 and throttle lever angle PLA, i.e., N2Dem_dt=f1(T1, PLA). 3) Based on the backup throttle characteristics of the engine in the existing control system, determine the relationship between the steady-state high-pressure rotor speed setpoint N2Dem_dt under the electronic speed controller and the intake total temperature T1 and the throttle lever angle PLA, i.e., N2Dem_bf=f2(T1, PLA); 4) Determine the ranges of T1 and PLA in steps 2) and 3) above, based on the temperature range of the engine's operating environment and the throttle lever angle range under operating conditions; 5) Based on the relationships in 2) and 3) above, and the ranges of T1 and PLA in 4), find the maximum value of the speed deviation between the existing control system's electronic throttle characteristic and the backup throttle characteristic, i.e., max[f1(T1, PLA)-f2(T1, PLA)]; 6) Based on the adjustment range of the main fuel pump regulator N2 readjustment in the existing control system, determine the maximum value Δ_JXmax of the N2 readjustment under the constraints of the existing mechanical structure; 7) Based on 5) and 6) above, the range for selecting the N2 readjustment amount Δ is determined as follows: Δ>max[f1(T1,PLA)-f2(T1,PLA)]+ Δ2 and Δ≤Δ_JXmax In the formula, Δ is the N2 readjustment amount, Δ2 is a constant value, N2Dem_ct is the N2 set value sensed by the backup advance mechanism when the readjustment solenoid valve is energized, N2Dem_dt is the N2 set value when the ESC is in main control, N2Dem_bf is the N2 set value when the backup is in main control, Δ_JXmax is the maximum value of N2 readjustment amount under the existing mechanical structure limitation of the main fuel pump regulator, T1 is the intake total temperature, and PLA is the throttle lever angle.

3. The α2 advance control method for a digital full-authority engine control system as described in claim 1, characterized in that, When the system is in ESC master control and the engine is in α2 advance control state, the N2 readjustment solenoid valve is de-energized; when the system is in ESC master control and the engine is not in α2 advance control state, the N2 readjustment solenoid valve is energized; when the system is in backup master control, the N2 readjustment solenoid valve is de-energized.

4. The α2 advance control method for a digital full-authority engine control system as described in claim 3, characterized in that, The first time threshold is 0.3s, with an adjustable range of 0.1s to 3s; the second time threshold is 0.5s, with an adjustable range of 0.1s to 5s.

5. The α2 advance control method for a digital full-authority engine control system as described in claim 4, characterized in that, The improved α2 advanced control system architecture operates as follows: The digital electronic controller determines the N2 readjustment solenoid valve operation command output to the main fuel pump regulator based on the main control status and α2 advance control status, and calculates the duty cycle signal PWMα2 output to the α2 duty cycle solenoid valve of the main fuel pump regulator based on the PID control algorithm. The controller includes a main control judgment module, an advance control judgment module, and a PID control module. The main control judgment module can determine whether the electronic control system (ECS) is activated based on the operating mode of the digital electronic controller (DEC). The advanced control judgment module can receive engine onboard parameters to determine whether the ESC system is in α2 advanced control state. The PID control module receives the compressor guide vane angle α2 collected by the actuator sensor, determines the N2 setting during ESC main control and the N2 setting value and α2 setting value α2Dem during backup main control, and calculates the duty cycle signal PWMα output to the main fuel pump regulator α2 duty cycle solenoid valve. 2； The main fuel pump regulator performs N2 readjustment control. The main fuel pump regulator includes an N2 readjustment solenoid valve and an α2 duty cycle solenoid valve. The N2 readjustment solenoid valve is used to receive the working command of the digital electronic controller to execute the N2 readjustment function. The α2 duty cycle solenoid valve receives the duty cycle signal PWMα2 of the digital electronic controller and adjusts the pressure of the rod chamber and rodless chamber of the actuator.

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