Method for avoiding interference of electrically adjustable and mechanically controlled fan blade angle

Abstract

The application belongs to the technical field of aero-engines, and particularly relates to a method for avoiding interference between electrically-controlled and mechanically-controlled fan adjustable blade angles, obtaining an inlet total temperature sensed by a main fuel pump regulator when an engine is on a test bench; obtaining an inlet total temperature collected by a digital electronic controller when the engine is on the test bench; calculating a temperature difference value AT of the inlet total temperature sensed by the main fuel pump regulator and the inlet total temperature collected by the digital electronic controller, calculating a deviation amount AN2r of a converted rotating speed based on the temperature difference value AT; and revising an initial upper and lower limit value of an A1 starting rotating speed out-of-factory test vehicle inspection requirement through the deviation amount AN2r. The application solves the A1 interference problem between electrically-controlled and mechanically-controlled systems by adjustment in the case of matching problems of temperature signals of a mechanical hydraulic system and a numerical control system without changing the system architecture and the hardware state.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine technology, and in particular relates to a method for avoiding interference between electrically controlled and mechanically controlled fan adjustable blade angles. Background Art

[0002] Aircraft engine control systems have gradually evolved from mechanical hydraulic control to electronically controlled systems with digital electronic controllers as their core. Control signals are converted from mechanical displacements into discrete digital quantities, significantly improving control precision. The state in which the digital electronic controller fully controls the entire process is called electronic control. The fan's adjustable blade angle A1 (herein, symbol A1 represents the adjustable blade angle of an aircraft engine fan) is a key component in regulating the engine's fan intake airflow.

[0003] The control principle of the electronically controlled state A1 is as follows: the engine low-pressure converted speed is calculated based on the relationship between the engine low-pressure speed and the inlet total temperature, expressed as N1r, and then the current A1 expected value, i.e. the given value, is calculated based on the current low-pressure converted speed; the A1 deviation value is obtained by subtracting the given value from the collected value; the A1 deviation value is calculated using the PID algorithm to obtain the duty cycle of the A1 control solenoid valve; after the duty cycle pulse acts on the solenoid valve, it controls the opening of the oil distribution valve, thereby controlling the pressure in the rod chamber and rodless chamber of the A1 actuator, ultimately achieving control of A1; the angle of A1 is then collected by the sensor and transmitted back to the controller to realize a closed loop.

[0004] The control principle of A1 in the mechanical backup state is as follows: based on the relationship between the engine high-pressure speed and the inlet total temperature, the engine high-pressure converted speed is obtained, expressed as N2r. Then, based on the current high-pressure converted speed, the current A1 expected value is obtained through the three-dimensional cam and the command lever. The A1 angle is transmitted to the main fuel pump regulator A1 control module through the feedback cable, and the mechanical signal is transmitted to the internal feedback cam. The deviation with the set planned given value is calculated, and the lever displacement is output to control the backup A1 valve position, thereby controlling the rod chamber and rodless chamber pressure of the A1 actuator, and finally achieving control of A1; the A1 angle is then transmitted back to the main fuel pump regulator by the feedback cable to realize a closed loop.

[0005] Because the ESC and backup system are two separate control systems, their inlet total temperature collection methods differ. The ESC's inlet total temperature is converted into an electrical signal and transmitted to the controller using the temperature-dependent behavior of resistance. The backup system's inlet total temperature utilizes the thermal expansion and contraction properties of rare gases to convert the temperature into control oil pressure, which is then transmitted to the main fuel pump regulator. Therefore, the two systems use different temperature measurement principles and are installed in different locations. Consequently, the measured temperatures differ, and the calculated expected A1 values ​​differ, leading to interference between the ESC and mechanical control's A1 values.

[0006] Since the currently used A1 electronic control system with mechanical backup has advantages such as high maturity, it is very necessary to avoid interference between the electronic control and the mechanical control A1 through adjustment measures without changing its architecture. Summary of the Invention

[0007] In order to solve the above problems, the present application provides a method to avoid interference between the electric control and the mechanical control of the fan's adjustable blade angle.

[0008] Obtain the total inlet temperature sensed by the main fuel pump regulator while the engine is on the test bench; Obtain the total inlet temperature sensed by the digital electronic controller while the engine is on the test bench;

[0009] calculating a temperature difference ΔT between the inlet total temperature sensed by the main fuel pump regulator and the inlet total temperature collected by the digital electronic controller, and calculating a deviation ΔN2r of the converted speed based on the temperature difference ΔT;

[0010] When the main fuel pump regulator is installed on the engine, the factory test inspection requirements for α1 starting speed adjustment are as follows: When the main fuel pump regulator is installed on the aircraft with the engine, the α1 start-up speed adjustment test inspection requirements are as follows: a, b, c, and d are all constants, a≤b≤c≤d, min and max are the initial upper and lower limits set according to the factory test inspection requirements of α1 starting speed.

[0011] Preferably,

[0012]

[0013] Among them, T1 is the total inlet temperature collected by the digital electronic controller, and n2 is the engine high-pressure rotor speed.

[0014] Preferably, the difference between a and b, and the difference between c and d increase with the increase of the temperature difference ΔT.

[0015] Preferably, when ΔT<5°C, b=k1*a; when 5°C≤ΔT≤8°C, b=k2*a; when ΔT>8°C, b=k3*a; and k3>k2>k1.

[0016] Preferably, k3=2.5; k2=2; k1=1.5.

[0017] Preferably, a takes the value 1.

[0018] The advantages of this application include: when there is a matching problem between the temperature signals of the mechanical hydraulic system and the CNC system and without changing the system architecture and hardware status, the interference problem between the electronic control and the mechanical control A1 can be solved by adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a method for avoiding interference between the electrically controlled and mechanically controlled fan blade angles in a preferred embodiment of the present application. DETAILED DESCRIPTION

[0020] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0021] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0022] The inlet total temperature T1 signal sensed by the main fuel pump regulator is the difference △P between the temperature command pressure from the inlet temperature sensing accessory (temperature package) and the stable oil discharge pressure. t The inlet total temperature (T1) signal collected by the digital electronic controller is measured by the engine inlet temperature sensor. Due to the different measurement principles and different engine installation locations, which are affected by intake airflow velocity, and the fact that both systems were tested both on the test bench and on the aircraft, the overall T1 temperature variation trends of the two systems are consistent. When the engine is on the test bench, the T1 temperature sensed by the main fuel pump regulator is approximately 4-5°C higher than the T1 temperature sensed by the digital electronic controller. When the engine is installed on the aircraft, the T1 temperature sensed by the main fuel pump regulator is approximately 7-8°C higher than the T1 temperature sensed by the digital electronic controller.

[0023] When the main fuel pump regulator is inspected at the factory, the difference between the temperature command pressure of the inlet temperature sensing accessory (temperature package) and the stable oil discharge pressure △P t The temperature signal transmitted is used to check the α1 starting speed (the converted speed when α1 starts to act). The inspection requirements are as follows:

[0024] When the main fuel pump regulator is assembled to the engine for the whole machine test run, due to the difference in T1 temperature signals of the two systems, the high pressure rotor conversion speed of the mechanical hydraulic system Lower than the calculated value of the ESC system You will find that the backup state α1 starting speed does not meet the requirements The inspection requirements are met by adjusting the adjustment pin on the main fuel pump regulator to reduce the α1 starting speed. The inspection requirement causes the α1 backup control law to shift to the left.

[0025] When the main fuel pump regulator is installed with the engine on the aircraft and the whole machine is tested and inspected, the difference in T1 temperature between the two systems becomes larger after installation, resulting in the high pressure rotor conversion speed of the mechanical hydraulic system after installation. Calculated by the ESC system The difference is larger than that of the engine on the test bench. It can be found that the α1 start speed adjustment of the engine on the test bench meets the requirements. After the inspection requirements, the α1 start speed adjustment after installation on the aircraft did not meet the requirements again. After adjusting the adjustment pin on the main fuel pump regulator to reduce the α1 start speed, it met the requirements. The inspection requirement causes the α1 backup control law to shift further to the left.

[0026] Because the backup system It cannot be displayed through the computer interface, so it can only be adjusted by electronic control. Adjusting the adjustment pin on the main fuel pump regulator caused the α1 backup control law to shift significantly to the left after installation compared to the factory main fuel pump regulator, while the ESC law remained unchanged. This could potentially interfere with the engine ESC control law.

[0027] The above problem is related to the matching of the T1 temperature signals of the mechanical hydraulic system and the CNC system. Without changing the system architecture and hardware status, the interference between the α1 electronic control and the backup law can only be avoided by correcting the α1 control law of the electronic control or adjusting the α1 control law requirements of the mechanical backup system.

[0028] 2. Solution

[0029] Through the mechanism analysis, we know that since the inspection requirement of α1 starting speed regulation is Furthermore, there is a difference in the T1 temperature signals of the two systems. Adjusting the adjustment pin of the main fuel pump regulator causes the α1 backup control law to deviate, which in turn causes interference. A solution is proposed as follows:

[0030] Step 1:

[0031] Formula (2) is obtained based on formula (1) and temperature deviation, which is the deviation of the converted speed.

[0032]

[0033] T1 is the total inlet temperature collected by the digital electronic controller, and n2 is the engine high-pressure rotor speed.

[0034] Step 2:

[0035] Set the inspection requirements for the α1 starting speed when the main fuel pump regulator is in different states:

[0036] Set the main fuel pump regulator α1 starting speed factory inspection requirements, for example

[0037] Step 3:

[0038] The main fuel pump regulator is installed on the engine and the factory test run inspection requirements for the α1 start speed adjustment on the test bench are as follows:

[0039] Step 4:

[0040] The main fuel pump regulator is installed on the aircraft with the engine. The inspection requirements for the α1 start speed adjustment test run are as follows:

[0041] The α1 starting speed inspection requirements must be met in different states. If any unqualified phenomenon occurs, the adjustment pin on the main fuel pump regulator can be adjusted to meet the requirements to avoid interference between the electric control and the mechanically controlled fan adjustable blade angle.

[0042] This method can be directly applied to aircraft engines with electric control as the main control and mechanical hydraulic backup system, and has good market application prospects.

[0043] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for avoiding interference between electrically controlled and mechanically controlled fan blade angles, characterized in that: Obtain the total inlet temperature sensed by the main fuel pump regulator while the engine is on the test bench; Obtain the total inlet temperature sensed by the digital electronic controller while the engine is on the test bench; calculating a temperature difference ΔT between the inlet total temperature sensed by the main fuel pump regulator and the inlet total temperature collected by the digital electronic controller, and calculating a deviation ΔN2r of the converted speed based on the temperature difference ΔT; When the main fuel pump regulator is installed on the engine, the factory test inspection requirements for α1 starting speed adjustment are as follows: When the main fuel pump regulator is installed on the aircraft with the engine, the α1 start-up speed adjustment test inspection requirements are as follows: a, b, c, and d are all constants, a≤b≤c≤d, min and max are the initial upper and lower limits set according to the factory test inspection requirements of α1 starting speed.

2. The method for avoiding interference between electrically controlled and mechanically controlled fan blade angles as claimed in claim 1, wherein: Among them, T1 is the total inlet temperature collected by the digital electronic controller, and n2 is the engine high-pressure rotor speed.

3. The method for avoiding interference between electrically controlled and mechanically controlled fan blade angles as claimed in claim 1, wherein: The difference between a and b, and the difference between c and d increase as the temperature difference △T increases.

4. The method for avoiding interference between electrically controlled and mechanically controlled fan blade angles as claimed in claim 3, wherein: When △T<5℃, b=k1*a; 5℃≤△T≤8℃, b=k2*a; △T>8℃, b=k3*a; k3>k2>k1.

5. The method for avoiding interference between electrically controlled and mechanically controlled fan blade angles as claimed in claim 4, wherein: k3=2.5; k2=2; k1＝1.5。 6. The method for avoiding interference between electrically controlled and mechanically controlled fan blade angles as claimed in claim 4, wherein: a takes the value 1.

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