A fault diagnosis method for engine speed non-following based on fuel parameters

Abstract

This invention discloses a fault diagnosis method for engine speed non-following based on fuel parameters, comprising: acquiring measured values ​​through engine sensors, including fuel flow setpoint, fuel flow feedback value, and current engine speed; acquiring engine function-related design values, including the maximum designed engine speed and fault judgment parameter thresholds; performing data conversion based on the measured values ​​and calculating the fault duration; calculating fault judgment parameters based on the fault duration, including the maximum main fuel following deviation WF_gs; and determining whether an engine speed non-following fault has occurred based on the fault judgment parameters and the fault judgment parameter thresholds. Based on the above technical solution, the engine speed non-following fault diagnosis algorithm can be improved and modified. Compared with existing engine speed non-following fault diagnosis schemes, this method can significantly eliminate interference factors caused by different flight states, and significantly improve the accuracy of fault isolation and diagnosis results.

Description

Technical Field

[0001] This invention relates to the field of aircraft engine health management, and more specifically, to a fault diagnosis method for engine speed non-following based on fuel parameters. Background Technology

[0002] The main pump regulator is the core of the aero-engine control system. It regulates the engine's fuel supply by sensing two parameters: atmospheric temperature and pressure, and compressor air pressure, thereby ensuring the safety, stability, and reliability of the aircraft in various flight states. To ensure the aircraft can respond quickly and enter combat, it is necessary to ensure the engine is fault-free during acceleration. Aero-engine fault diagnosis technology is one of the key technologies in the evolution of aero-engine maintenance strategies from planned maintenance to dynamic, condition-based maintenance. It aims to monitor and isolate faults in real time based on engine sensor measurements.

[0003] Domestic research and development companies primarily extract fault information from historical engine test data and limited fault data, establishing fault diagnosis methods based on this historical data. However, in real-world conditions, the fuel supply during engine acceleration is determined by the acceleration controller of the main pump regulator. Given the uncertain engine state when throttle response fails to follow the engine speed, existing fault diagnosis methods based on historical data are not precise enough for accurate fault location and still require manual screening and confirmation. Therefore, a technical solution is needed that can accurately locate engine faults and diagnose speed-following faults, unaffected by flight conditions. Summary of the Invention

[0004] To achieve the above objectives, this application provides a fault diagnosis method for engine speed non-following based on fuel parameters, comprising:

[0005] The engine sensors acquire measurement values, including fuel flow setpoint, fuel flow feedback value, and current engine speed; and the engine function-related design values ​​are acquired, including the maximum design engine speed and fault judgment parameter thresholds.

[0006] Data is converted based on measured values, and the duration of the fault is statistically analyzed.

[0007] The fault judgment parameters are calculated based on the fault duration. The fault judgment parameters include the maximum value of the main fuel following deviation, WF_gs.

[0008] Determine whether a speed non-following fault has occurred based on the fault judgment parameters and fault judgment parameter thresholds.

[0009] The data transformation includes the following steps:

[0010] Calculate the first fuel flow parameter, which is generated from the given fuel flow value;

[0011] A speed non-following fault counter is generated based on the first fuel flow parameter and the fuel flow feedback value.

[0012] Furthermore, generating a speed-following fault counter includes:

[0013] Obtain the fuel flow feedback value at a given time point;

[0014] If the fuel flow feedback value is less than the first fuel flow parameter, set the engine speed non-following fault count to 1 at the set time point; otherwise, set the engine speed non-following fault count to 0.

[0015] The storage time point and the corresponding non-following fault count constitute the generation speed non-following fault counter.

[0016] The fault duration is generated based on the duration of time when the speed does not follow the fault counter and the count value is 1.

[0017] Furthermore, when calculating the maximum value of the main fuel follow-up deviation WF_gs, it is determined whether the ratio of the current engine speed to the designed maximum engine speed is greater than or equal to 70%. If so, the fault duration is multiplied by the current engine speed to obtain the maximum value of the main fuel follow-up deviation WF_gs. Otherwise, it is determined that no engine failure to follow the engine speed has occurred, and the maximum value of the main fuel follow-up deviation WF_gs is not calculated.

[0018] Furthermore, if the fault judgment parameter is greater than the fault judgment parameter threshold, it is determined that a speed non-following fault has occurred; otherwise, it is determined that no speed non-following fault has occurred.

[0019] According to the present invention, the fault diagnosis algorithm for non-following speed can be improved and modified. Compared with the existing fault diagnosis scheme for non-following speed speed, the method can significantly eliminate interference factors caused by different flight states and significantly improve the accuracy of fault isolation and diagnosis results. Attached Figure Description

[0020] Figure 1 This is a flowchart of a fault diagnosis method for engine speed not following according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the engine working normally diagnostic results provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of an engine speed not following the specified state according to an embodiment of the present invention;

[0023] Figure 4This is a schematic diagram of the fault diagnosis results for engine speed not following according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the fault diagnosis results for engine speed not following in the existing method. Detailed Implementation

[0025] This invention provides a method for diagnosing engine speed non-following faults by combining dynamic data such as engine speed with design data and calculating the maximum value of the main fuel following deviation in the program. Through this method, the isolation and diagnosis of engine speed non-following faults can be accurately achieved.

[0026] The specific implementation of the present invention will now be described in detail with reference to the accompanying drawings.

[0027] Figure 1 A fault diagnosis method flowchart for engine speed not following is provided, as shown in the figure, including the following steps:

[0028] Step S100: Obtain measurement values ​​through engine sensors; obtain engine function-related design values;

[0029] The measurements obtainable from the engine's sensors include: fuel flow setpoint, fuel flow feedback, and current engine speed;

[0030] Engine function-related design values ​​include the maximum designed engine speed and predefined threshold parameters, such as fault diagnosis parameter thresholds. In practical applications, fault diagnosis parameter thresholds are defined based on experience, for example, set to 50.

[0031] Step S110: Perform data conversion based on the measured values ​​and calculate the fault duration;

[0032] The data conversion in this step can be achieved using a data conversion algorithm program run in MATLAB. The conversion process yields parameters such as the main fuel following deviation and the duration of the deviation. The specific conversion process includes the following steps:

[0033] 1) Calculate the first fuel flow parameter: The first fuel flow parameter is a parameter related to a given value, which is generated by multiplying a given coefficient by the given fuel flow value; where the given coefficient is usually assigned a value of 0.99;

[0034] 2) Generate a speed non-following fault counter based on the first fuel flow parameter and the fuel flow feedback value:

[0035] Specifically, the process of generating a speed counter that does not follow the fault includes:

[0036] Obtain fuel flow feedback values ​​at specific time points;

[0037] Compare the fuel flow feedback value with the first fuel flow parameter: If the fuel flow feedback value is less than the first fuel flow parameter, set the engine speed non-following fault count value to 1 at that time point; otherwise, set the engine speed non-following fault count value to 0.

[0038] The time points and corresponding non-following fault counts in the above comparison process are stored to form a speed non-following fault counter.

[0039] In subsequent judgment applications, when the speed non-following fault count is 0, it can be determined that the engine has not experienced a speed non-following fault.

[0040] Step S120: Calculate the fault judgment parameters based on the fault duration, wherein the fault judgment parameters include the maximum value of the main fuel following deviation WF_gs;

[0041] The fault duration in this step is generated based on the duration of the time when the speed does not follow the fault counter and the count is 1.

[0042] When calculating fault diagnosis parameters, determine whether the ratio of the current engine speed to the maximum designed engine speed is greater than or equal to 70%. If so, calculate the maximum value of the main fuel following deviation WF_gs, i.e.: WF_gs = fault time length × current engine speed; otherwise, determine that no engine speed following failure has occurred.

[0043] In practical applications, when the engine is at idle speed or below, the sensitivity of interference factors to engine performance becomes very prominent: even a small change in conditions, such as a slight fluctuation in fuel flow, can cause a large change in engine speed, making fault diagnosis of engine speed not keeping up meaningless. Therefore, in this invention, fault diagnosis is only performed when the ratio of the current engine speed to the designed maximum engine speed is greater than or equal to a certain fixed value (e.g., 70%), in order to eliminate the influence of interference factors.

[0044] Step S130: Determine whether a speed non-following fault has occurred based on the fault judgment parameters and the fault judgment parameter threshold.

[0045] Specifically, if the fault judgment parameter at a given time point is greater than the fault judgment parameter threshold, it is determined that a speed non-following fault has occurred at that time point; otherwise, it is determined that no speed non-following fault has occurred.

[0046] The diagnostic method in this step is essentially based on the engine's given speed and actual speed. Figure 3 A comparison chart of the engine's set speed and actual speed is provided when the engine speed does not follow the speed fault diagnosed by WF_gs. The vertical axis represents the speed, N2 represents the actual speed, and N2dem represents the set speed. It can be seen that when the speed does not follow the speed fault is detected, there is a large difference between the actual speed and the set speed.

[0047] For example, a fault judgment parameter threshold of 50 can be predefined, such as... Figure 2 As shown: the horizontal axis represents the running time, and the vertical axis represents the parameter used to determine the fault (maximum value of main fuel follower deviation WF_gs) obtained according to this method. Since the maximum value of the main fuel follower deviation WF_gs is 35, it does not exceed the threshold of the fault determination parameter. Figure 2 During the indicated time period, the engine did not experience a speed misalignment fault. When the maximum main fuel follow-through deviation WF_gs is greater than 50, such as... Figure 4 As shown by the peak point of the curve, WF_gs reaches 250 at 250s, which greatly exceeds the fault judgment parameter threshold. It can be located that the speed non-following fault occurred at this time point. It can be seen that the fault diagnosis method provided by the present invention can accurately diagnose the speed non-following fault, accurately locate the time of the fault occurrence, and facilitate finding problems in the control of the main pump device.

[0048] Figure 5 A schematic diagram of the diagnostic results for speed non-following faults using existing methods is provided. The horizontal axis of the diagram represents the running time, and the vertical axis represents the parameters used to determine the fault based on existing technology. Due to the excessive number of pulses in the diagram, it is impossible to accurately pinpoint the time of the fault occurrence.

[0049] Overall, this invention achieves fault diagnosis based on a comprehensive algorithm by acquiring and transforming data: First, engine fuel flow information is acquired and transformed to construct a speed non-following fault counter. Then, the length of each segment of the counter is statistically analyzed, and the obtained length is compared with the current engine speed to generate a parameter for fault judgment. This parameter is then compared with a threshold, enabling precise isolation of engine speed faults using this method. This solves the problems of insufficient fault diagnosis and location, and interference from engine status, inherent in existing speed non-following fault diagnosis methods.

[0050] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the present invention is not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A fault diagnosis method for engine speed non-following based on fuel parameters, characterized in that, include: The engine sensors acquire measurement values, including fuel flow setpoint, fuel flow feedback value, and current engine speed; and the engine function-related design values ​​are acquired, including the maximum design engine speed and fault judgment parameter thresholds. Data conversion is performed based on the measured values ​​to calculate the fault duration. The data conversion includes the following steps: calculating a first fuel flow parameter, which is generated from a given fuel flow value; generating a speed non-following fault counter based on the first fuel flow parameter and a fuel flow feedback value; generating the speed non-following fault counter includes: acquiring the fuel flow feedback value at a given time point; if the fuel flow feedback value is less than the first fuel flow parameter, setting the speed non-following fault count at that time point to 1, otherwise setting the speed non-following fault count to 0; storing the time point and the corresponding non-following fault count to form the generated speed non-following fault counter. The fault duration is generated based on the duration of time when the count value is 1 in the fault counter for non-following rotation speed. The fault judgment parameters are calculated based on the fault duration. The fault judgment parameters include the maximum value of the main fuel follow-up deviation WF_gs. Specifically, it is determined whether the ratio of the current engine speed to the maximum designed engine speed is greater than or equal to 70%. If so, the fault duration is multiplied by the current engine speed to obtain the maximum value of the main fuel follow-up deviation WF_gs. Otherwise, it is determined that no speed non-following fault has occurred. The fault judgment parameters and the fault judgment parameter threshold are used to determine whether a speed non-following fault has occurred; if the fault judgment parameters are greater than the fault judgment parameter threshold, it is determined that a speed non-following fault has occurred; otherwise, it is determined that no speed non-following fault has occurred.

Images