A method and system for diagnosing a sudden change in the rotational speed of an auxiliary power unit

Abstract

The application provides a kind of auxiliary power device revolution abrupt change fault diagnosis method and system, comprising: collecting fault information, drawing fault analysis tree, determine the multiple bottom events that cause fault;Based on determining the multiple bottom events that cause fault, carry out fault reproduction verification test, install the multiple accessories of fault section to qualified section auxiliary power device, observe whether the fault reproduces;When fault reproduces, by the way of replacing the accessory of fault section with qualified piece one by one to carry out test, lock the fault source accessory that causes fault.Repeatable, comparable test replaces the blind disassembly and replacement that depends on personal experience, quickly peels out the real fault piece from the multiple systems that interweave, solves the problem that it is difficult to accurately locate in traditional troubleshooting because of involving multiple systems, complex associated factors, significantly improves the diagnosis efficiency of revolution mutation, overtemperature and the like, reduces the probability of repeated fault occurrence.

Description

Technical Field

[0001] This invention belongs to the field of fault diagnosis technology for aero-engines, and specifically relates to a method and system for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit. Background Technology

[0002] The aircraft auxiliary power unit (APU) consists of a gas turbine engine, a gearbox, a DC starter generator, etc. It is mainly used to start aircraft engines, supply power to the onboard electrical grid, and can be used as an emergency power source to supply power to airborne equipment in the air. In-flight starting must meet specific performance requirements.

[0003] An malfunction of the APU can lead to ground or in-flight start-up failures. The small gas turbine engine it contains has a complex structure, multiple failure modes, and many related factors, making troubleshooting difficult and directly affecting the normal operation of the aircraft.

[0004] Currently, for APU in-flight start-up performance, a given start-up and fuel control program is used. The core is to ignite the combustion chamber within a specified time and accelerate the APU engine to a loadable speed while ensuring that the compressor does not surge and the turbine inlet temperature does not exceed the limit, thereby ensuring the start-up effect.

[0005] The existing control program is designed only for the normal start-up process and does not fully consider the complex fault characteristics of the APU gas turbine engine. It cannot effectively deal with various fault modes such as sudden speed changes and overheating, nor can it solve the problem of many fault-related factors. It is difficult to fundamentally avoid abnormal situations such as unsuccessful start-up and cannot completely solve the impact of APU faults on the normal operation of the aircraft. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit, in order to solve the problem of being unable to effectively deal with various fault modes such as sudden changes in rotational speed and overheating.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit, comprising: Collect fault information, draw a fault analysis tree, and identify multiple underlying events that caused the fault; Based on the identified multiple underlying events leading to the failure, a failure reproduction verification test was conducted. Multiple accessories of the faulty unit were installed on the auxiliary power unit of the qualified unit, and the failure was observed to see if it was reproduced. When the fault recurs, the faulty component is identified by replacing each accessory with a qualified one and conducting a test run.

[0008] Furthermore, the collection of fault information includes: A fault diagnosis framework is developed based on the fault symptoms, which include a sudden change in the speed of the auxiliary power unit or an overheating phenomenon.

[0009] Furthermore, the process of drawing a fault analysis tree to identify multiple underlying events leading to the fault includes: Draw a fault analysis tree for the rapid change in the speed of the auxiliary power unit, and determine the corresponding base events of the fault tree for the auxiliary power unit, accessories, and flight attachments.

[0010] Furthermore, the fault reproduction verification test involves installing multiple accessories from the faulty unit onto the auxiliary power unit of the qualified unit and observing whether the fault is reproduced, including: Install all the accessories to be checked from the faulty unit onto the auxiliary power unit of the qualified unit and test run it. If the fault recurs, it is confirmed that there is a source of the fault among all the attachments to be investigated.

[0011] Furthermore, the process of replacing the accessories of the faulty unit one by one with qualified parts and then testing the unit to pinpoint the faulty accessory includes checking one or more of the following in sequence: cables, centrifugal switches, fuel pumps, starter valves, solenoid valves, and starter generators.

[0012] Furthermore, the troubleshooting method for the cable is as follows: replace all accessories of the faulty unit except the cable with qualified parts, and conduct a test run. If the start-up fails or the speed drops, the cable is determined to be the source of the fault. The troubleshooting method for the centrifugal switch is as follows: replace all accessories except the centrifugal switch of the faulty unit with qualified parts, conduct a test run, and determine whether the centrifugal switch is working properly by checking the first signal. If the first signal is abnormal and the speed drops, the centrifugal switch is determined to be a faulty part. The troubleshooting method for the fuel pump is as follows: replace all accessories except the fuel pump of the faulty unit with qualified parts, and test drive it. If the speed drops, the fuel pump is determined to be the source of the fault. The troubleshooting method for the starting valve is as follows: replace all accessories of the faulty unit except the starting valve with qualified parts, and conduct a test run. If the speed drops, the starting valve is determined to be the source of the fault. The troubleshooting method for the solenoid valve is as follows: replace all accessories of the faulty unit except the solenoid valve with qualified parts, and perform a test run. If the speed drops, the solenoid valve is determined to be the source of the fault. The troubleshooting method for the starter generator is as follows: replace all accessories of the faulty unit except the starter generator with qualified parts, and conduct a test run. If the speed drops, the starter generator is determined to be the source of the fault.

[0013] Furthermore, if the fault does not recur after installing all the accessories to be checked on the faulty unit onto the auxiliary power unit of the qualified unit and conducting a test run, then the control system of the aircraft accessories should be checked.

[0014] Secondly, the present invention provides a fault diagnosis system for sudden changes in the rotational speed of an auxiliary power unit, comprising: The information collection module is used to collect fault information, draw fault analysis trees, and identify multiple underlying events that cause the fault. The verification module is used to perform a fault reproduction verification test based on multiple identified underlying events that cause the fault. Multiple accessories of the faulty unit are installed on the auxiliary power unit of the qualified unit, and the fault is observed to be reproduced. The output module is used to identify the faulty accessory by replacing each accessory of the faulty unit with a qualified part and conducting a test run when the fault is reproduced.

[0015] Thirdly, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit.

[0016] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit.

[0017] Compared with the prior art, the present invention has the following technical effects: This application analyzes fault phenomena, collects fault information, and elucidates the working principles of electrical, fuel, and control systems to develop a clear troubleshooting framework. Based on this, a fault tree is drawn, categorizing all relevant factors that could cause drastic changes in engine speed as base events to avoid overlooking potential fault points. In the verification phase, the fault is reproduced by installing the entire set of accessories from the faulty assembly onto a qualified device, confirming that the fault source indeed exists within that batch of accessories. Subsequently, a test run is conducted by replacing qualified parts one by one, sequentially verifying accessories such as cables, centrifugal switches, fuel pumps, starter valves, solenoid valves, and starter generators. The absence of speed drops and overheating phenomena after each replacement is observed, thus gradually narrowing down the fault cause to a specific component. This process replaces blind replacement based on personal experience with repeatable and comparable testing, quickly identifying the true faulty component from multiple intertwined systems. It solves the problem of difficulty in accurately locating faults in traditional troubleshooting due to the involvement of multiple systems and complex related factors, significantly improving the diagnostic efficiency of faults such as sudden speed changes and overheating, and reducing the probability of recurring faults. Attached Figure Description

[0018] Figure 1 Fault diagnosis process for rapid changes in the rotational speed of auxiliary power unit.

[0019] Figure 2 Fault analysis tree for rapid changes in the rotational speed of the auxiliary power unit.

[0020] Figure 3 Flowchart of troubleshooting method for overheating faults in auxiliary power unit.

[0021] Figure 4 This is a flowchart of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings: Example 1: This invention provides a method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit, comprising: Collect fault information, draw a fault analysis tree, and identify multiple underlying events that caused the fault; Based on the identified multiple underlying events leading to the failure, a failure reproduction verification test was conducted. Multiple accessories of the faulty unit were installed on the auxiliary power unit of the qualified unit, and the failure was observed to see if it was reproduced. When the fault recurs, the faulty component is identified by replacing each accessory with a qualified one and conducting a test run.

[0023] Step 1: Collect fault information. Based on the fault symptoms, analyze the working principles of the related electrical system, fuel system, and control system, and formulate an overall fault diagnosis strategy. (See...) Figure 1 .

[0024] Step 2: Draw a fault analysis tree for the rapid change in the speed of the auxiliary power unit, and determine the corresponding base events of the fault tree for the auxiliary power unit, accessories, and flight attachments; Step 3: Verify each APU speed change fault according to the fault tree, observe whether the auxiliary power unit experiences a speed drop and overheating, and determine the fault point by reproducing the fault (see...). Figure 3 ): 1. Install all six accessories (cable, starter valve, fuel pump, centrifugal switch, fuel solenoid valve, and starter generator) of the faulty auxiliary power unit onto the qualified auxiliary power unit and conduct a verification test run. During the process, run the unit idle twice to check the sealing and performance parameters. If the start is unsuccessful, it indicates that there is a fault among the six accessories, and proceed to step 2. Otherwise, run the generator for 5 minutes to check whether the motor is working properly and observe whether the fault recurs. 2. If the fault recurs, continue to pinpoint the source of the fault. Replace all accessories of the auxiliary power unit of the faulty unit except for the cable with qualified parts, run it idle once to check the sealing, apply load to multiple units and observe whether the speed drops. If the start is unsuccessful or the start is successful but the speed drops, then the cable is the source of the fault. 3. If the start-up is successful and the speed does not drop, and the cable is not faulty, then continue to pinpoint the source of the fault. Replace all accessories of the auxiliary power unit except the centrifugal switch with qualified parts, run it idle to check the sealing, check the first signal, and determine if the centrifugal switch is working properly. If the first signal is abnormal and the speed of the auxiliary power unit drops, then simultaneously observe the change in exhaust temperature. If an abnormal operating temperature occurs, stop the machine immediately. At this point, the centrifugal switch is the faulty component.

[0025] 4. If the engine speed does not decrease, continue to pinpoint the source of the fault. Replace all accessories except the fuel pump with qualified parts, run the engine idle twice to check the sealing and performance parameters, and observe whether the engine speed decreases under load multiple times. If the engine speed does not decrease, the fuel pump is normal and there is no fault; if the engine speed decreases, the fuel pump is the source of the fault.

[0026] 5. If the speed does not decrease, continue to pinpoint the source of the fault. Replace all accessories except the starting valve with qualified parts, run the valve idle once to check the sealing, and observe whether the speed decreases under load multiple times. If the speed does not decrease, the starting valve is normal and there is no fault; if the speed decreases, the starting valve is the source of the fault.

[0027] 6. If the speed does not decrease, continue to pinpoint the source of the fault. Replace all accessories except the solenoid valve with qualified parts, check the sealing during no-load operation, and observe whether the speed decreases under load multiple times. If the speed does not decrease, the solenoid valve is normal and not faulty; if the speed decreases, the solenoid valve is the source of the fault.

[0028] 7. If the speed does not decrease, continue to lock the source of the speed decrease fault. Replace all accessories except the starter generator with qualified parts, proceed to step one, and observe whether the test run phenomena are the same. Check the sealing and performance parameter status during no-load operation. If starting is unsuccessful, there is a fault among the six accessories, and proceed to step one. Otherwise, generate electricity for 5 minutes, apply load to multiple units, and observe whether the speed decreases. If the speed decreases, the starter generator is faulty.

[0029] 8. If the fault does not recur, investigate the aircraft accessory control system. Check the aircraft accessory starter control box, the interlocking devices in the aircraft electrical system, and the aircraft electrical control system test plan to determine the fault location.

[0030] 9. The order of 2-7 above can be changed arbitrarily.

[0031] This invention addresses the failure of an engine to start in the air and the corresponding sudden drop in the speed of its turbine generator unit. It involves conducting troubleshooting simulation tests, drawing a fault tree, and systematically checking each component. This method allows for the scientific, orderly, and rapid identification and pinpointing of the fault source and the faulty component. Verification is then performed through fault reproduction to accurately locate the cause of the fault and develop troubleshooting measures for the sudden drop in the auxiliary power unit's speed. This provides a reference for diagnosing faults such as unsuccessful in-air starts, sudden speed changes, and overheating. Currently, this method has been applied in practical work, with good test results, significantly reducing the failure rate.

[0032] Example 2: During the startup process of a turbine generator, the start-up failed, the speed dropped, and the exhaust temperature exceeded the limit for more than 20 seconds. Ground inspection revealed that the turbine generator exhibited signs of burning. To quickly diagnose the cause of the fault, the following methods were adopted: The first step, based on the above situation, is to collect fault information. Analyzing the auxiliary power unit's working principle based on the fault symptoms reveals that the speed drop is caused by excessive load or insufficient fuel supply, leading to an unstable and inefficient operating range. This further causes a sharp increase in exhaust temperature, exceeding the temperature limit. Possible causes include: faults in the unit itself, faults in unit accessories, and faults in aircraft accessories. Based on this, the overall fault diagnosis approach is as follows: Figure 1 As shown.

[0033] The second step was to draw a fault analysis tree for the rapid change in the device's rotational speed in order to find the specific cause of the fault and to investigate the relevant fault factors.

[0034] The third step is to perform fault reproduction verification tests according to the events listed in the fault tree. The cables, starter valve, fuel pump, centrifugal switch, fuel solenoid valve, and starter generator of the faulty device are installed on a qualified device. The fault is verified and tested one by one, observing whether the device experiences a drop in speed and overheating. The fault source is determined by reproducing the fault, and the faulty component is identified. 1) Install all six accessories (cable, starter valve, fuel pump, centrifugal switch, fuel solenoid valve, and starter generator) of the faulty auxiliary power unit onto the qualified auxiliary power unit and conduct a verification test run to reproduce the speed drop and overheating. During the process, the unit was run idle twice; the sealing was checked and it was found to be working normally (n=96%, T=380℃). After six load tests, the performance parameters were checked, and the unit was found to be malfunctioning, with speed drop and unsuccessful starting. This was repeated twice, with the same symptoms, and the unit could not complete a 56-60KW load. This indicates that there is a fault source among the six accessories. 2) If the fault recurs, continue to pinpoint the source of the fault. Replace all accessories of the auxiliary power unit of the faulty unit except for the cable with qualified parts, run it idle once to check the sealing, and apply load four times to observe whether the speed drops. 3) If the start-up is successful and the speed does not drop, and the cable is fault-free, then continue to pinpoint the fault source. Replace all accessories of the faulty auxiliary power unit except for the centrifugal switch with qualified parts, perform an no-load test to check the sealing, check the first signal, and determine if the centrifugal switch is working properly. The no-load test was normal, but an abnormal situation occurred when the return oil valve was opened. The eddy current set the speed continuously, dropping from 96% to 80%, with a continuing downward trend. At this point, manually closing the return oil valve restored the speed to normal. The centrifugal switch's function is to disconnect the generator load when the speed drops to 80%~83%.

[0035] 4) The engine speed does not decrease. Having ruled out a centrifugal switch issue, continue to pinpoint the source of the fault. Replace all accessories except the faulty fuel pump with qualified parts. Run the generator idle twice to check sealing and performance parameters, and observe for a decrease in engine speed after four load cycles. The eddy current generator equipped with the faulty fuel pump malfunctioned under load for six cycles, with the engine speed decreasing. However, the centrifugal switch functioned protectively, automatically disconnecting the generator load when the speed dropped to 81%. This was repeated twice, with the same phenomenon observed, failing to complete a 56-60 kW load. Therefore, the fuel pump was determined to be the source of the fault.

[0036] 5) To simulate fault reproduction, the turbine's speed was maintained at 4800 r / min for one minute. Afterward, the speed dropped to 4500 r / min, and the flow rate increased rapidly from 42 L / h to 110 L / h. Replacing the faulty fuel pump immediately restored normal operation. In conclusion, the cause of the turbine generator speed drop was determined to be a fuel pump regulator malfunction.

[0037] This embodiment takes a fault in which a turbine generator fails to start in the air, its speed drops, and its exhaust temperature exceeds the limit as the diagnostic object, and describes in detail the implementation process of this method.

[0038] During the startup process, the turbine generator failed to start, the speed dropped, the exhaust temperature exceeded the limit, and the duration exceeded 20 seconds. Ground inspection revealed that the turbine generator had ablation.

[0039] The first step is to collect fault information and formulate an overall fault diagnosis strategy based on the fault symptoms. Analysis of the auxiliary power unit's operating principle based on the fault symptoms indicates that the speed drop is caused by excessive load or insufficient fuel supply, leading to an unstable and inefficient operating range. This further causes a sharp increase in exhaust temperature, exceeding the temperature limit. Possible causes include: faults in the unit itself, faults in unit accessories, and faults in aircraft accessories. Based on this, the overall fault diagnosis strategy is formulated as follows: Figure 1 As shown.

[0040] The second step is to draw a fault analysis tree to identify multiple underlying events causing the fault. To pinpoint the specific cause of the fault, a fault analysis tree for sudden changes in unit speed is drawn. All relevant factors that could lead to sudden speed changes are categorized into multiple underlying events for systematic investigation, avoiding overlooking potential fault points. The fault analysis tree is as follows: Figure 2 As shown.

[0041] The third step is to perform fault reproduction verification tests according to the events listed in the fault tree. The specific process is as follows: Figure 3 As shown, multiple accessories from the faulty unit were installed on the auxiliary power unit of a qualified unit, and the fault was observed to reappear. When the fault reappeared, the faulty unit's accessories were replaced one by one with qualified parts for testing, thus pinpointing the faulty accessory. Applying this method in practical work, repeatable and comparable testing replaces blind replacement based on personal experience, quickly identifying the true faulty component from multiple intertwined systems. This solves the problem of difficulty in accurately locating the fault in traditional troubleshooting due to the involvement of multiple systems and complex related factors.

[0042] The specific verification process is as follows: All six accessories of the faulty auxiliary power unit—cable, starter valve, fuel pump, centrifugal switch, fuel solenoid valve, and starter generator—were installed on a qualified auxiliary power unit for verification testing. The resulting speed drop and overheating were reproduced, confirming the fault source was within that batch of accessories. During the process, the unit was run idle twice; the sealing was checked and it appeared to be functioning normally (n=96%, T=380℃). Six load tests were then conducted to check the performance parameters; abnormal operation was observed, with speed drop and unsuccessful starts. This was repeated twice, with the same symptoms, failing to complete a 56-60KW load. This indicates that a fault exists among the six accessories.

[0043] After the fault was reproduced, the source of the fault was further identified. The accessories of the faulty unit were replaced one by one with qualified parts for test runs to pinpoint the specific faulty component. First, the cables were checked. All accessories of the auxiliary power unit of the faulty unit, except for the cables, were replaced with qualified parts. The unit was run idle once to check for leaks. Four load tests were then conducted to observe whether the speed dropped. The result was a successful start without speed drop, and the cables were found to be faulty.

[0044] Continue troubleshooting the centrifugal switch. Replace all accessories of the faulty auxiliary power unit (excluding the centrifugal switch) with qualified parts. Run the unit idle once to check the sealing and the first signal to determine if the centrifugal switch is working properly. The unit worked normally during idle, but an abnormal situation occurred when the return oil valve was opened. The eddy current generator speed continuously decreased from 96% to 80%, with a continuing downward trend. Manually closing the return oil valve at this point restored the speed to normal. The centrifugal switch's function is to disconnect the generator load when the speed drops to 80%–83%. In this step, the speed did not decrease, ruling out a problem with the centrifugal switch.

[0045] The fuel pump was further investigated. All accessories except the fuel pump were replaced with qualified parts. The unit was run idle twice to check sealing and performance parameters, and then loaded four times to observe if the speed dropped. The eddy current device with the faulty fuel pump failed to operate properly under load for six cycles, with the speed dropping. However, the centrifugal switch functioned correctly, automatically disconnecting the generator load when the speed dropped to 81%. This was repeated twice, with the same phenomenon observed, failing to complete the 56-60 kW load. Therefore, the fuel pump was identified as the source of the fault. Thus, by replacing and verifying each component one by one, the cause of the fault was gradually narrowed down to a specific part, accurately pinpointing the cause.

[0046] To simulate fault reproduction, the turbine's speed was maintained at 4800 r / min for one minute. Afterward, the speed dropped to 4500 r / min, and the flow rate increased rapidly from 42 L / h to 110 L / h. Replacing the faulty fuel pump immediately restored normal operation. In conclusion, the cause of the turbine generator speed drop was determined to be a fuel pump regulator malfunction. This method scientifically and systematically identified and determined the fault source quickly, and then verified it through fault reproduction, accurately pinpointing the cause. The test run verification showed good results, significantly reducing the failure rate and providing a reliable reference for diagnosing faults such as unsuccessful in-flight starts, sudden speed changes, and overheating.

[0047] It should be noted that during the troubleshooting of cables, centrifugal switches, fuel pumps, starting valves, solenoid valves, and starter generators, the order in which these accessories are inspected can be arbitrarily changed and is not limited to the order described in this embodiment. If the fault does not recur after installing all the accessories to be inspected from the faulty unit onto the auxiliary power unit of the qualified unit for testing, then the control system of the aircraft accessories should be checked. This includes inspecting the aircraft accessory starter adjustment box, the interlocking devices in the aircraft electrical system, and the test plan for the aircraft electrical control system to determine the fault location.

[0048] In another embodiment of the present invention, a fault diagnosis system for abrupt changes in the rotational speed of an auxiliary power unit is provided, which can be used to implement the above-mentioned fault diagnosis method for abrupt changes in the rotational speed of an auxiliary power unit. Specifically, the system includes: The information collection module is used to collect fault information, draw fault analysis trees, and identify multiple underlying events that cause the fault. The verification module is used to perform a fault reproduction verification test based on multiple identified underlying events that cause the fault. Multiple accessories of the faulty unit are installed on the auxiliary power unit of the qualified unit, and the fault is observed to be reproduced. The output module is used to identify the faulty accessory by replacing each accessory of the faulty unit with a qualified part and conducting a test run when the fault is reproduced.

[0049] The module division in this embodiment of the invention is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the invention can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0050] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used in the operation of a fault diagnosis method for rapid changes in the rotational speed of an auxiliary power unit.

[0051] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the operating system of the terminal. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for diagnosing a sudden change in the rotational speed of an auxiliary power unit in the above embodiments.

[0052] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0053] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0054] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0055] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit, characterized in that, include: Collect fault information, draw a fault analysis tree, and identify multiple underlying events that caused the fault; Based on the identified multiple underlying events leading to the failure, a failure reproduction verification test was conducted. Multiple accessories of the faulty unit were installed on the auxiliary power unit of the qualified unit, and the failure was observed to see if it was reproduced. When the fault recurs, the faulty component is identified by replacing each accessory with a qualified one and conducting a test run.

2. The method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit according to claim 1, characterized in that, The collection of fault information includes: A fault diagnosis framework is developed based on the fault symptoms, which include a sudden change in the speed of the auxiliary power unit or an overheating phenomenon.

3. The method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit according to claim 1, characterized in that, The process of drawing a fault analysis tree identifies multiple underlying events that cause the fault, including: Draw a fault analysis tree for the rapid change in the speed of the auxiliary power unit, and determine the corresponding base events of the fault tree for the auxiliary power unit, accessories, and flight attachments.

4. The method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit according to claim 1, characterized in that, The fault reproduction verification test involves installing multiple accessories from the faulty unit onto the auxiliary power unit of the qualified unit and observing whether the fault is reproduced. This includes: Install all the accessories to be checked from the faulty unit onto the auxiliary power unit of the qualified unit and test run it. If the fault recurs, it is confirmed that there is a source of the fault among all the attachments to be investigated.

5. The method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit according to claim 4, characterized in that, The process of replacing each accessory of the faulty unit with a qualified one and then testing the unit to pinpoint the faulty accessory involves checking one or more of the following in sequence: cables, centrifugal switches, fuel pumps, starter valves, solenoid valves, and starter generators.

6. The method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit according to claim 5, characterized in that, The troubleshooting method for the cable is as follows: replace all accessories of the faulty unit except the cable with qualified parts, and test run. If the start-up fails or the speed drops, the cable is determined to be the source of the fault. The troubleshooting method for the centrifugal switch is as follows: replace all accessories except the centrifugal switch of the faulty unit with qualified parts, conduct a test run, and determine whether the centrifugal switch is working properly by checking the first signal. If the first signal is abnormal and the speed drops, the centrifugal switch is determined to be a faulty part. The troubleshooting method for the fuel pump is as follows: replace all accessories except the fuel pump of the faulty unit with qualified parts, and test drive it. If the speed drops, the fuel pump is determined to be the source of the fault. The troubleshooting method for the starting valve is as follows: replace all accessories of the faulty unit except the starting valve with qualified parts, and conduct a test run. If the speed drops, the starting valve is determined to be the source of the fault. The troubleshooting method for the solenoid valve is as follows: replace all accessories of the faulty unit except the solenoid valve with qualified parts, and perform a test run. If the speed drops, the solenoid valve is determined to be the source of the fault. The troubleshooting method for the starter generator is as follows: replace all accessories of the faulty unit except the starter generator with qualified parts, and conduct a test run. If the speed drops, the starter generator is determined to be the source of the fault.

7. The method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit according to claim 1, characterized in that, If the fault does not recur after installing all the faulty components onto the auxiliary power unit of a qualified component and conducting a test run, then the control system of the aircraft components should be investigated.

8. A fault diagnosis system for abrupt changes in the rotational speed of an auxiliary power unit, characterized in that, include: The information collection module is used to collect fault information, draw fault analysis trees, and identify multiple underlying events that cause the fault. The verification module is used to perform a fault reproduction verification test based on multiple identified underlying events that cause the fault. Multiple accessories of the faulty unit are installed on the auxiliary power unit of the qualified unit, and the fault is observed to be reproduced. The output module is used to identify the faulty accessory by replacing each accessory of the faulty unit with a qualified part and conducting a test run when the fault is reproduced.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for diagnosing faults caused by rapid changes in the rotational speed of an auxiliary power unit as described in any one of claims 1 to 7.

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