Acoustic sensor monitoring for turbine engine gearbox

Abstract

A system may include a first acoustic sensor, a processor operably connected to the first acoustic sensor, and a memory operably connected to the processor. The memory stores therein a plurality of acoustic features indexed according to associated operating conditions of the turbine engine. The processor is configured to receive acoustic data from the first acoustic sensor, identify a current operating condition of the turbine engine, select one of the plurality of acoustic features in the memory based on the current operating condition, generate a comparison result using the selected one of the plurality of acoustic features and the acoustic data, and transmit the comparison result to the first acoustic sensor. And identifying that the gearbox of the turbine engine has a maintenance condition when the comparison result indicates a deviation greater than or equal to a preset threshold.

Description

Technical Field

[0001] The present disclosure generally relates to jet engines, and more particularly, to acoustic sensor monitoring for a turbine engine gearbox. Background Art

[0002] Aircraft typically employ various types of sensors to gather information regarding flight conditions, engine operating conditions, and / or conditions of specific sub-components of the aircraft engines. In particular, temperature sensors or similar sensors can be used to monitor whether various engine sub-components have issues that require maintenance and / or replacement. Brief Description of the Drawings

[0003] Various needs are at least partially met by providing the first acoustic sensor monitoring for a turbine engine gearbox as described in the following detailed description, particularly when studied in conjunction with the accompanying drawings. Aspects of the present specification for a person of ordinary skill in the art are set forth in a complete and enabling disclosure, including its best mode, in the specification with reference to the accompanying drawings, wherein:

[0004] Figure 1 is a cross-sectional view of a gas turbine engine for an aircraft;

[0005] Figure 2 is a block diagram of a monitoring system according to various embodiments of the present disclosure;

[0006] Figure 3 is a block diagram of another monitoring system according to various embodiments of the present disclosure;

[0007] Figure 4A is a cross-sectional view of a mounted gearbox according to various embodiments of the present disclosure;

[0008] Figure 4B shows Figure 4A an enlarged partial cross-sectional side view of a portion of the mounted gearbox; and

[0009] Figure 5 is a flowchart of a method according to various embodiments of the present disclosure.

[0010] The elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions and / or relative positions of some elements in the drawings may be exaggerated relative to other elements to assist in enhancing the understanding of the various embodiments of the present disclosure. Additionally, common but well-understood elements that are useful or necessary in commercially viable embodiments are typically not depicted so as to provide a less obstructed view of these different embodiments of the present disclosure. Certain actions and / or steps may be described or depicted in a particular order of occurrence, but those skilled in the art will understand that such specificity of sequence is not actually required. Detailed Implementation Modes

[0011] Except as otherwise set forth herein with different specific meanings, the terms and expressions used herein have the ordinary technical meanings given to them by those skilled in the above technical field. Unless otherwise specifically indicated, the word "or" used herein shall be construed to have a disjunctive structure rather than a conjunctive structure. Unless otherwise stated herein, terms such as "coupled", "fixed", "attached to", etc. refer to both direct coupling, fixing or attachment and indirect coupling, fixing or attachment through one or more intermediate components or features.

[0012] Unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" include plural references.

[0013] As used throughout the specification and claims herein, approximating language is applied to modify any quantitative representation that can vary without resulting in a change in the basic function associated therewith. Accordingly, values modified by terms such as "about", "approximately", and "substantially" are not limited to the precise values specified. In at least some instances, the approximating language can correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the components and / or systems. For example, the approximating language can refer to within a margin of 10%.

[0014] Current systems for monitoring the health of a turbofan engine and / or its specific components, such as a gearbox, rely on sensors that are physically attached to a moving element of the turbofan engine or gearbox in order to provide useful measurements. Because the sensors are attached to the moving element, the placement location within the turbofan engine can be limited. Additionally, current health monitoring systems are typically limited to searching for a single type of fault and do not have much flexibility in updating the faults being monitored after installation. These are significant challenges in the context of an aviation application environment.

[0015] Generally, aspects of the present disclosure can be employed with an acoustic sensor that is used in combination with a processor and memory of an aircraft control system to sense acoustic characteristics or data of an aircraft engine or a sub-component thereof, such as a gearbox. Such a system can compare the sensed acoustic characteristics or data with “control” characteristics of a normally operating engine or gearbox. A first acoustic sensor can be configured to monitor or target frequencies and amplitudes representative of a given component or interface. If the processor identifies a sufficient shift in the acoustic characteristics (e.g., a detected difference from the control characteristics reaches or exceeds a preset threshold), the processor can trigger an alert or a similar indicator regarding the need for a maintenance action to prevent future failures of the engine and / or gearbox. Compared to currently utilized sensors, using acoustic sensors can increase placement flexibility within a turbofan engine because acoustic sensors do not need to be physically located on a moving element to provide meaningful data. Additionally, compared to some types of existing sensors, acoustic sensors can reduce weight, can be set to identify different types of fault conditions, and / or have improved processing flexibility to update specific faults monitored after installation.

[0016] Referring now to the drawings, where like numerals indicate like elements throughout the several views, Figure 1 is a cross-sectional view of a gas turbine engine. The gas turbine engine is a high-bypass turbofan jet engine, referred to herein as “turbine engine 10”. Turbine engine 10 defines an axial direction A (extending parallel to a longitudinal centerline 12 for reference) and a radial direction R. Generally, turbine engine 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of fan section 14.

[0017] The depicted example core turbine engine 16 generally includes a generally tubular outer casing 18 that defines an annular inlet 20. Tubular outer casing 18 surrounds, in serial flow relationship: a compressor section that includes a low-pressure (LP) compressor 22 and a high-pressure (HP) compressor 24; a combustion section 26; a turbine section that includes a high-pressure (HP) turbine 28 and a low-pressure (LP) turbine 30; and an exhaust nozzle section 32. A high-pressure (HP) shaft or spool 34 drivingly connects HP turbine 28 to HP compressor 24. A low-pressure (LP) spool 36 drivingly connects LP turbine 30 to LP compressor 22.

[0018] The fan section 14 includes a variable pitch fan 38 having a plurality of fan blades 40 coupled to a disk 42 in a spaced apart manner. As depicted, the fan blades 40 extend generally radially outward from the disk 42 along a radial direction R. Each of the fan blades 40 is rotatable relative to the disk 42 about a pitch axis P by being operably connected to a suitable actuating member 44, and the actuating member 44 is configured to collectively and uniformly change the pitch of the fan blades 40. The fan blades 40, disk 42, and actuating member 44 together are rotatable about a longitudinal centerline 12 via a low pressure spool 36 across a gearbox 46. The gearbox 46 includes a plurality of gears for reducing the rotational speed of the LP spool 36 to a more efficient rotational fan speed.

[0019] Still referring Figure 1 to the example embodiment of, the disk 42 is covered by a rotatable front hub 48 that is aerodynamically shaped to facilitate airflow through the plurality of fan blades 40. Additionally, the exemplary fan section 14 includes an annular fan casing or nacelle 50 that circumferentially surrounds at least a portion of the variable pitch fan 38 and / or the core turbine engine 16. It should be understood that the nacelle 50 can be configured to be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced outlet guide vanes 52. Further, a downstream section 54 of the nacelle 50 can extend over an outer portion of the core turbine engine 16 to define a bypass airflow passage 56 therebetween.

[0020] During operation of the turbine engine 10, a quantity of air 58 enters the turbine engine 10 through an associated inlet 60 of the nacelle 50 and / or the fan section 14. As the quantity of air 58 passes through the fan blades 40, a first portion 62 of the air 58, as indicated by the arrow, is directed or guided into the bypass airflow passage 56, and a second portion 64 of the air 58, as indicated by the arrow, is directed or guided into the LP compressor 22. The ratio between the first portion 62 of the air 58 and the second portion 64 of the air 58 is commonly referred to as the bypass ratio. Then, as the second portion 64 of the air 58 is directed through the HP compressor 24 and into the combustion section 26, the pressure of the second portion 64 of the air 58 increases, and in the combustion section 26, the second portion 64 of the air 58 is mixed with fuel and burned to provide combustion gases 66. Subsequently, the combustion gases 66 are directed through a hot flow path or hot section flow path of the HP turbine 28 and the LP turbine 30, where a portion of the thermal energy and / or kinetic energy is extracted from the combustion gases 66.

[0021] Then, the combustion gases 66 are directed through an exhaust nozzle section 32 of the core turbine engine 16 to provide propulsion thrust. At the same time, as the first portion 62 of the air 58 is directed through the bypass airflow passage 56 before being exhausted from an exhaust nozzle section 76 of the fan of the turbine engine 10, the pressure of the first portion 62 of the air 58 significantly increases, also providing propulsion thrust.

[0022] However, it should be understood that Figure 1 the exemplary turbine engine 10 depicted in is merely an example, and in other example embodiments, aspects of the present disclosure may additionally or alternatively be applied to any other suitable gas turbine engine. For example, in other example embodiments, the turbine engine 10 may include an open fan architecture in which the outer nacelle 50 is omitted, or may alternatively be any other suitable aero gas turbine engine, such as a turbojet engine, a turboprop engine, a turbofan engine, etc. Additionally, in still other example embodiments, the exemplary turbine engine 10 may include or be operably connected to any other suitable accessory system. Additionally or alternatively, the exemplary turbine engine 10 may not include or be inoperably connected to one or more of the aforementioned accessory systems.

[0023] Now referring to Figure 2 , a turbine engine gearbox monitoring system 100 is shown. The turbine engine gearbox monitoring system 100 may be used in conjunction with the turbine engine 10, particularly in conjunction with the gearbox 46 shown in Figure 2 . Specifically, the turbine engine gearbox monitoring system 100 may include a first acoustic sensor 102 located near the gearbox 46 of the turbine engine 10 (e.g., the first acoustic sensor 102 is located at a position where the first acoustic sensor 102 can receive audio from the gearbox 46, such as between the gearbox 46 and the inlet of the HP turbine 28 of Figure 1 ), a processor 104 operably connected to the first acoustic sensor 102, and a memory 106 operably connected to the processor 104. A plurality of acoustic signatures 108 indexed according to one or more associated operating conditions of the turbine engine 10 may be stored in the memory 106. In some embodiments, the turbine engine gearbox monitoring system 100 may further include a temperature sensor 110 located near the gearbox 46 and operably coupled to the processor 104.

[0024] The processor 104 may include, for example, a microprocessor, a system-on-chip, an application specific integrated circuit (ASIC), and / or a field programmable gate array (FPGA). The memory 106 may include, for example, a charge-based storage medium (such as an electrically erasable programmable read only memory (EEPROM) or a random access memory (RAM)), or other non-transitory computer-readable media (such as an optically or magnetically based storage device). The processor 104 may be operably coupled to or be part of a full-authority digital engine controller (FADEC). The FADEC typically has full authority over the operating parameters of the turbine engine 10 and cannot be manually overridden. The FADEC typically operates by receiving a plurality of input variables of the current flight conditions, including but not limited to air density, throttle lever position, engine temperature, engine pressure, etc. It receives, analyzes the inputs and is used to determine operating parameters, such as but not limited to the fuel flow rate of the turbine engine 10, the stator vane position, the bleed valve position, etc. The FADEC may also control the start-up and / or restart operations of the turbine engine 10.

[0025] The operating conditions to which each of the plurality of acoustic signatures 108 is indexed may include specific operating states of the turbine engine 10. These operating states may include a ground idle state, a takeoff thrust state, a flight idle state, cruise, and other dynamic or steady-state operating states of the turbine engine 10 that can be well-defined and last for a sufficient time for the first acoustic sensor 102 and the processor 104 to be able to monitor.

[0026] In operation, the first acoustic sensor 102 is configured to output acoustic data representative of the sound 112 emitted from and / or around the gearbox 46. The processor 104 is configured to receive the acoustic data from the first acoustic sensor 102 and identify the current operating conditions of the turbine engine 10. In some embodiments, the processor 104 identifies the current operating conditions from flight data or additional sensor inputs received by the processor 104 (such as engine speed, wind speed, thrust demand, altitude, etc.). Additionally or alternatively, when the processor 104 is separated from the FADEC, the processor 104 may receive a direct indicator of the current operating conditions from other processing components of the turbine engine 10, such as the FADEC. Further, the processor 104 may be configured to identify the current operating conditions after the current operating conditions or an indicator thereof occur within a minimum time period associated with achieving thermal equilibrium with the turbine engine 10.

[0027] The processor 104 is also configured to select one of the plurality of acoustic signatures 108 in the memory 106 based on current operating conditions and use the selected one of the plurality of acoustic signatures 108 and the acoustic data to generate a comparison result. The processor 104 is generally also configured to identify a maintenance condition for the gearbox 46 and / or the turbine engine 10 when the comparison result indicates a deviation greater than or equal to a preset threshold (e.g., a difference compared to the selected one of the plurality of acoustic signatures 108). In some embodiments, the preset threshold is at least three decibels. As described in more detail below, the deviation can represent a difference in the amplitude and / or frequency of the acoustic data. In some embodiments, the deviation can also correspond to the presence of a sound in the gearbox 46 or other monitored components of the turbine engine 10 at an unexpected time. In some embodiments, once the deviation has been present for at least a minimum time period, the processor 104 identifies the maintenance condition as present.

[0028] The maintenance condition can include a specific component failure or damage that generally degrades the performance of the gearbox 46 and / or the turbine engine 10 and for which corrective action should be taken as soon as possible. However, in some embodiments, the maintenance condition can generally include a prediction of an impending component failure or damage relative to the gearbox 46 and / or the turbine engine 10. In these embodiments, the turbine engine gearbox monitoring system 100 can predict the maintenance condition before the performance of the gearbox 46 and / or the turbine engine 10 has substantially degraded.

[0029] Generally, the acoustic data output by the first acoustic sensor 102 is a digital or analog representation of the sound 112 (e.g., a varying voltage and / or current signal corresponding to the sound 112). The acoustic data can be a continuous signal between the first acoustic sensor 102 and the processor 104 or can be a time-limited analog or digital sample of the sound 112. As described in more detail below, the acoustic data can be time-domain data or frequency-domain data.

[0030] The plurality of acoustic signatures 108 can include prior acoustic data generated by the first acoustic sensor 102 during one or more test operations of the turbine engine 10 at each associated operating condition. Specifically, the plurality of acoustic signatures 108 can include digital or analog representations of the sounds 112 output by a normal operating version of the turbine engine 10 at each operating condition. The one or more test operations can include an engine break-in or power assurance procedure performed after an initial build of the turbine engine 10 or after a subsequent maintenance action on the turbine engine 10. Additionally, in some embodiments, the processor 104 can be configured to populate the plurality of acoustic signatures 108 with characteristics of the operating conditions of the turbine engine 10 for which no associated signatures are yet stored in the memory 106. This population of the plurality of acoustic signatures 108 can be done during the first opportunity identified by the processor 104, such as the first steady flight operation for a duration of at least a minimum period of time to allow the turbine engine 10 to reach thermal equilibrium (e.g., the first flight after installation of the turbine engine 10 on an aircraft or after maintenance of the turbine engine 10). Because the plurality of acoustic signatures 108 are populated at the earliest opportunity, the risk that one of the populated signatures does not correspond to normal operation of the turbine engine 10 is minimized.

[0031] The prior acoustic data that constitutes the plurality of acoustic signatures 108 can be time-domain data, frequency-domain data, or both. Such time-domain and frequency-domain data corresponds to normal or expected operation of the turbine engine 10 at a particular corresponding operating condition or set of conditions. As described above, the plurality of acoustic signatures 108 are indexed in the memory 106 according to the corresponding operating condition or set of conditions so that the processor 104 can select the time-domain and / or frequency-domain data associated with one or more current operating conditions of the turbine engine 10 identified by the processor 104 during operation of the turbine engine gearbox monitoring system 100. The plurality of acoustic signatures 108 can also include frequency-domain data and / or time-domain data generated from one or more acoustic sensors of a turbine engine different from the turbine engine 10 in which the turbine engine gearbox monitoring system 100 is employed. Similarly, in some embodiments, the plurality of acoustic signatures 108 includes default acoustic data corresponding to the expected operation of the turbine engine 10 at each associated operating condition.

[0032] In some embodiments, the plurality of acoustic features 108 include steady-state features that do not correspond to previous acoustic data generated by the first acoustic sensor 102 during one or more test operations of the turbine engine 10. Instead, the steady-state features include a running average of previous acoustic data output from the first acoustic sensor 102 during a current steady-state operation of the turbine engine 10 (e.g., a situation where the turbine engine 10 maintains a constant speed and / or altitude). Thus, the operating conditions to which the steady-state features are indexed include the steady-state operating conditions of the turbine engine 10. In this way, the plurality of acoustic features 108 do not need to include separate features for each possible steady-state operation of the aircraft, but can track deviations under the general expectation that the acoustic data corresponding to the sound 112 output from the gearbox 46 during any steady-state operation or its running average is approximately uniform under normal operating conditions.

[0033] Additionally, in some embodiments, other features among the plurality of acoustic features 108 (such as the steady-state features described above) can be features that do not correspond to previous acoustic data generated by the first acoustic sensor 102 during one or more test operations of the turbine engine 10. In these embodiments, the plurality of acoustic features 108 can include a similar running average of previous acoustic data output from the first acoustic sensor 102, and / or the maximum or minimum value of the acoustic data received from the first acoustic sensor 102 at a specific frequency, frequency range, or all frequencies (e.g., the maximum or minimum sound level in time-domain analysis or the maximum or minimum frequency intensity in frequency-domain analysis). Additionally, in some embodiments, the value of the preset threshold can be different for each of the associated operating conditions of the turbine engine 10. For example, in a case where a selected one of the plurality of acoustic features 108 includes a maximum or minimum value, the processor 104 can compare the acoustic data received from the first acoustic sensor 102 at each frequency or at a specified frequency value or range with the maximum or minimum value, and identify the presence of a maintenance condition when the deviation between the acoustic data and the maximum or minimum value is greater than or equal to the preset threshold. In some of these embodiments, for this type of plurality of acoustic features 108, the preset threshold can be set to zero or close to zero, such that any deviation of the acoustic data below or above the maximum or minimum value will trigger the identification of a maintenance condition.

[0034] In a case where the plurality of acoustic features 108 include time-domain data, such time-domain data can be output by the first acoustic sensor 102 during one or more test operations of the turbine engine 10. In these embodiments, the acoustic data includes current time-domain data corresponding to the sound 112 emitted from the gearbox 46. Additionally, the processor 104 is configured to compare the current time-domain data with the corresponding time-domain data of one of the plurality of acoustic features 108 selected by the processor 104 to generate a comparison result.

[0035] In cases where multiple acoustic features 108 include frequency domain data, such frequency domain data can be generated from the output of the first acoustic sensor 102 during one or more test operations of the turbine engine 10. In particular, the frequency domain data can be the Fourier transform (e.g., fast Fourier transform "FFT" or a similar transform) of the time domain data output by the first acoustic sensor 102 during one or more test operations of the turbine engine 10. This Fourier transform can be done by the processor 104, or by another similar system that is part of or separate from the turbine engine 10 and the turbine engine gearbox monitoring system 100. Additionally, in some embodiments, the first acoustic sensor 102 can be configured to directly output frequency domain data rather than time domain data.

[0036] However, in cases where multiple acoustic features 108 include frequency domain data and the first acoustic sensor 102 outputs time domain data, the processor 104 is further configured to transform (e.g., perform an FFT or a similar transform) the current time domain data from the sound 112 output by the first acoustic sensor 102 into current frequency domain data. The processor 104 can then compare the current frequency domain data with the corresponding frequency domain data of one of the multiple acoustic features 108 selected by the processor 104 to generate a comparison result.

[0037] Various embodiments for determining when the comparison result indicates a deviation greater than or equal to a preset threshold are possible. For example, in some embodiments, when the average difference between one of the multiple acoustic features 108 selected by the processor 104 and the acoustic data or its transform is greater than or equal to the preset threshold, the comparison result indicates a deviation greater than or equal to the preset threshold. Additionally, in some embodiments, when the difference between one of the multiple acoustic features 108 selected by the processor 104 and the acoustic data or its transform at one or more comparison points is greater than or equal to the preset threshold, the comparison result indicates a deviation greater than or equal to the preset threshold.

[0038] The comparison points between one of the multiple acoustic features 108 selected by the processor 104 and the acoustic data can include the same relative time position within each data set of the time domain variation of the data, as well as the same frequency value or the binned range of frequency values of the frequency domain variation of the data. In some embodiments, the data compared at each comparison point can include the decibel level or a similar indicator of the amplitude or loudness of the sound 112 at a particular comparison point (e.g., relative time position or frequency value or the binned range of frequency values).

[0039] Now refer to Figure 3, showing that in some embodiments, the turbine engine gearbox monitoring system 100 may include one or more additional acoustic sensors 202 different from the first acoustic sensor 102. The one or more additional acoustic sensors 202 may be located near the gearbox 46 and are configured to output additional corresponding acoustic data in response to sound 112 emitted from the gearbox 46. In these embodiments, the plurality of acoustic features 108 are further indexed according to an association with one of the first acoustic sensor 102 or one of the one or more additional acoustic sensors 202. In these embodiments, the processor 104 is further configured to receive additional corresponding acoustic data from the one or more additional acoustic sensors 202. The processor 104 is also configured to additionally select one of the plurality of acoustic features 108 in the memory 106 based on an association with the first acoustic sensor 102, and to select additional acoustic features among the plurality of acoustic features 108 in the memory 106 based on an association with the one or more additional acoustic sensors 202 and the current operating conditions of the turbine engine 10 identified by the processor 104. The processor 104 is also configured to generate a comparison result using the additional acoustic features and the additional acoustic data among the selected plurality of acoustic features 108, such as by comparing the additional acoustic features among the selected plurality of acoustic features 108 with the additional corresponding acoustic data or its transformation.

[0040] In addition, in these embodiments, when the acoustic data or its transform deviates from one of the plurality of acoustic features 108 selected at at least one comparison point by at least a preset threshold, the comparison result may indicate a deviation greater than or equal to the preset threshold. When the additional corresponding acoustic data or its transform deviates from an additional acoustic feature among the plurality of acoustic features 108 selected at one or more comparison points by at least the preset threshold, the comparison result also indicates a deviation greater than or equal to the preset threshold (e.g., when the acoustic data from the first acoustic sensor 102 and any of the one or more additional acoustic sensors 202 shows a deviation, a maintenance condition is identified as present). Alternatively, in some embodiments, when the acoustic data or its transform deviates from one of the plurality of acoustic features 108 selected at one or more comparison points by at least the preset threshold, and when the additional corresponding acoustic data or its transform deviates from an additional acoustic feature among the plurality of acoustic features 108 selected at one or more comparison points by at least the preset threshold, the comparison result indicates a deviation greater than or equal to the preset threshold (e.g., when the acoustic data from all sensors of the first acoustic sensor 102 and the one or more additional acoustic sensors 202 indicates a deviation, a maintenance condition is identified as present). In other embodiments, when the acoustic data from at least a preset number of sensors of the first acoustic sensor 102 and the one or more additional acoustic sensors 202 shows a deviation, a maintenance condition may be similarly identified as present. For example, if the turbine engine gearbox monitoring system 100 includes four or more acoustic sensors, when the acoustic data from at least two acoustic sensors shows a deviation, a maintenance condition may be similarly identified as present. It should be understood that different values of the preset number of acoustic sensors are possible.

[0041] The first acoustic sensor 102 and / or one or more additional acoustic sensors 202 can be configured to generate acoustic data from portions of the sound 112 within different frequency ranges. For example, in some embodiments, the portions of the sound 112 that are converted into acoustic data can include portions having frequencies in the range of about 25 Hz to about 250 Hz, which corresponds to the frequencies generated by the input shaft speed of the LP turbine 30 (e.g., about 1500 rpm to about 15000 rpm). In other embodiments, the portions of the sound 112 that are converted into acoustic data can include portions having frequencies in the range of about 20 Hz to about 20 kHz, which corresponds to the audible frequency range. In still other embodiments, the portions of the sound 112 that are converted into acoustic data can include portions having frequencies in the range of about 300 Hz to about 3 kHz, which corresponds to the tooth passing frequencies of the gears of the gearbox 46. In some embodiments, instead of the first acoustic sensor 102 and / or one or more additional acoustic sensors 202 converting portions of the sound 112 having frequencies within one or more of the ranges described herein, the processor 104 and / or other components of the turbomachine gearbox monitoring system 100 (such as low-pass filters, high-pass filters, band-pass filters, etc.) can further process the acoustic data to remove portions of the signals outside of the relevant frequency ranges (e.g., about 25 Hz to about 250 Hz, about 20 Hz to about 20 kHz, and / or about 300 Hz to about 3 kHz).

[0042] The first acoustic sensor 102 and / or one or more additional acoustic sensors 202 can be located at various different positions near the gearbox 46 and / or the drive system of the turbomachine 10, such as juxtaposed or adjacent to a bearing, to detect bearing faults based on location and processing. For example, in Figure 4A and Figure 4BTherein, a mounted gearbox 46 according to some embodiments is shown. The first acoustic sensor 102 and / or one or more additional acoustic sensors 202 may be mounted on the flexible mount 300, the torque cone 302, the engine static structure 304, the gearbox housing 306, the gearbox mount 308, and / or other static or rotating engine structures near the gearbox 46. The first acoustic sensor 102 and / or one or more additional acoustic sensors 202 may be located within and / or on the gearbox 46 and / or on a nearby frame / ground plane to enable differential signal analysis. The flexible mount 300, the torque cone 302, and the engine static structure 304 for mounting the first acoustic sensor 102 or one or more additional acoustic sensors 202 are further shown and described in U.S. Patent Publication 2023 / 0212987, which is incorporated herein by reference in its entirety. The gearbox housing 306, the gearbox mount 308, and other internal gearbox locations are further shown and described in U.S. Patents 11,287,353 and 10,788,394, which are incorporated herein by reference in their entirety.

[0043] The first acoustic sensor 102 and one or more additional acoustic sensors 202 may include uniaxial omnidirectional microphones, triaxial multi-directional microphones, etc. Additionally, in some embodiments, the first acoustic sensor 102 and one or more additional acoustic sensors 202 may be replaced or supplemented by capacitive or inductive proximity sensors (such as piezoelectric sensors or accelerometers). Further, in any embodiment, the first acoustic sensor 102 and one or more additional acoustic sensors 202 may be connected to the processor 104 either wired or wirelessly.

[0044] In some embodiments, the processor 104 may activate an indicator 204 electrically coupled to the processor 104 in response to identifying the presence of a maintenance condition ( Figure 3) The indicator 204 can be used to notify the pilot and / or ground personnel of maintenance issues. In some embodiments, the indicator 204 can include maintenance messages and / or notifications generated by the processor 104. The message or notification can be transmitted to and displayed on a display in the flight deck of the aircraft to notify the pilot of the issue. The message or notification can also be transmitted to one or more ground sources immediately or upon the next landing of the aircraft to trigger a maintenance process to correct the identified maintenance condition. In some embodiments, the indicator 204 can include a light in the flight deck or elsewhere on the aircraft that is activated by the processor 104 when a maintenance condition is identified as present. Additionally, in some embodiments, the indicator 204 can be configured to output or indicate different severities depending on the magnitude, duration, and number of differences detected between the acoustic data from the first acoustic sensor 102 and / or one or more additional acoustic sensors 202 and the relevant acoustic features among the plurality of acoustic features 108 of the current operating conditions of the turbine engine 10.

[0045] Additionally, in some embodiments, the processor 104 is further configured to use the temperature data of the gearbox 46 received from the temperature sensor 110 to verify the existence of a maintenance condition. The temperature data can include the oil temperature or a dedicated temperature of the gearbox 46. The memory 106 can also store therein temperature values associated with the normal operation of the gearbox 46 and / or the turbine engine 10 for comparison with the temperature data when used to confirm the existence of a maintenance condition.

[0046] Reference Figure 5 and Figure 2 and, the turbine engine gearbox monitoring system 100 can be used in conjunction with a method 400 for monitoring the turbine engine 10 and / or the gearbox 46. The method 400 includes receiving acoustic data from the first acoustic sensor 102 at the processor 104, as shown at 402. The method 400 then includes identifying the current operating conditions of the turbine engine 10, as shown at 404. Next, the method 400 includes selecting one of the plurality of acoustic features 108 in the memory 106 based on the current operating conditions, as shown at 406. Then, the method 400 includes generating a comparison result using the selected one of the plurality of acoustic features 108 and the acoustic data, as shown at 408. Next, the method 400 includes determining whether the comparison result indicates a deviation greater than or equal to a preset threshold, as shown at 410. When there is a deviation greater than or equal to the preset threshold, the method 400 includes identifying that there is a maintenance condition in the gearbox 46, as shown at 412. Then, after identifying the existence of a maintenance condition or determining that there is no deviation greater than or equal to the preset threshold, the method 400 includes returning to step 402 to receive acoustic data from the first acoustic sensor 102 again.

[0047] It should now be understood that the turbine engine gearbox monitoring system 100 disclosed herein represents an improved system and an improved method for monitoring whether components of a turbine engine are in a maintenance condition. In particular, the turbine engine gearbox monitoring system 100 utilizes a more flexible acoustic sensor in combination with audio signal processing to identify when a turbine engine component is experiencing a maintenance condition. Compared to current systems, using an acoustic sensor provides improved flexibility in terms of sensor location and processing modifications.

[0048] A further aspect of the present disclosure is provided by the subject matter of the following clauses:

[0049] A turbine engine gearbox monitoring system, the system comprising: a first acoustic sensor located near the gearbox of the turbine engine, the first acoustic sensor being configured to output acoustic data representative of sound emitted from the gearbox; a processor operably connected to the first acoustic sensor; a memory operably connected to the processor, the memory storing therein a plurality of acoustic characteristics indexed according to associated operating conditions of the turbine engine, wherein the processor is configured to: receive the acoustic data from the first acoustic sensor; identify the current operating condition of the turbine engine; select one of the plurality of acoustic characteristics in the memory based on the current operating condition; use the selected one of the plurality of acoustic characteristics and the acoustic data to generate a comparison result; and when the comparison result indicates a deviation greater than or equal to a preset threshold, identify that the gearbox is in a maintenance condition.

[0050] The system according to any of the preceding clauses, further comprising one or more additional acoustic sensors different from the first acoustic sensor, the one or more additional acoustic sensors being located near the gearbox of the turbine engine and being configured to output respective additional acoustic data in response to the sound emitted from the gearbox, wherein the plurality of acoustic characteristics are further indexed according to an association with one of the first acoustic sensor or the one or more additional acoustic sensors, and wherein the processor is further configured to: receive the respective additional acoustic data from the one or more additional acoustic sensors; additionally select the one of the plurality of acoustic characteristics in the memory based on the association with the first acoustic sensor; select additional acoustic characteristics of the plurality of acoustic characteristics in the memory based on the association with the one or more additional acoustic sensors and the current operating condition of the turbine engine; and use the selected additional acoustic characteristics of the plurality of acoustic characteristics and the respective additional acoustic data to generate the comparison result.

[0051] The system according to any of the preceding clauses, wherein the processor is configured to generate the comparison result by comparing the one of the selected plurality of acoustic features with the acoustic data or its transform, and comparing the additional acoustic feature of the selected plurality of acoustic features with the corresponding additional acoustic data or its transform, wherein when the acoustic data or its transform deviates from the one of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, the comparison result indicates the deviation greater than or equal to the preset threshold, and wherein when the corresponding additional acoustic data or its transform deviates from the additional acoustic feature of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, the comparison result also indicates the deviation greater than or equal to the preset threshold.

[0052] The system according to any of the preceding clauses, wherein the processor is configured to generate the comparison result by comparing the one of the selected plurality of acoustic features with the acoustic data or its transform, and comparing the additional acoustic feature of the selected plurality of acoustic features with the corresponding additional acoustic data or its transform, wherein when the acoustic data or its transform deviates from the one of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, and when the corresponding additional acoustic data or its transform deviates from the additional acoustic feature of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, the comparison result indicates the deviation greater than or equal to the preset threshold.

[0053] The system according to any of the preceding clauses, further comprising a temperature sensor located near the gearbox, and wherein the processor is further configured to use the temperature data of the gearbox received from the temperature sensor to verify the existence of the maintenance condition.

[0054] A method for monitoring a turbine engine gearbox, the method comprising: receiving, at a processor, acoustic data from a first acoustic sensor, the acoustic data representing sounds emitted from a gearbox of a turbine engine; identifying a current operating condition of the turbine engine; selecting, based on the current operating condition, one of a plurality of acoustic features in a memory, the plurality of acoustic features being indexed in the memory according to associated operating conditions of the turbine engine; using the one of the selected plurality of acoustic features and the acoustic data to generate a comparison result; and identifying a maintenance condition of the gearbox when the comparison result indicates a deviation greater than or equal to a preset threshold.

[0055] The method according to any of the preceding clauses further includes: transforming current time-domain data corresponding to the sound emitted from the gearbox into current frequency-domain data, the acoustic data including the current time-domain data, wherein the plurality of acoustic features includes corresponding frequency-domain data generated from the output of the first acoustic sensor during one or more test operations of the turbine engine; and comparing the current frequency-domain data with the corresponding frequency-domain data of one of the plurality of acoustic features to generate the comparison result.

[0056] The system and method according to any of the preceding clauses, wherein the first acoustic sensor is located at a gearbox housing, a gearbox mount, a flexible mount, a torque cone, or other static or rotating engine structures near the gearbox.

[0057] The system and method according to any of the preceding clauses, wherein the first acoustic sensor includes a uniaxial unidirectional microphone or a triaxial multi-directional microphone.

[0058] The system and method according to any of the preceding clauses, wherein when the average difference between one of the selected plurality of acoustic features and the acoustic data or its transformation is greater than or equal to the preset threshold, the comparison result indicates a deviation greater than or equal to the preset threshold.

[0059] The system and method according to any of the preceding clauses, wherein when the difference between one of the selected plurality of acoustic features and the acoustic data or its transformation at one or more comparison points is greater than or equal to the preset threshold, the comparison result indicates a deviation greater than or equal to the preset threshold.

[0060] The system and method according to any of the preceding clauses, wherein the plurality of acoustic features includes default acoustic data corresponding to the expected operation of the turbine engine under each associated operating condition.

[0061] The system and method according to any of the preceding clauses, wherein the plurality of acoustic features includes previous acoustic data generated by the first acoustic sensor during one or more test operations of the turbine engine under each associated operating condition.

[0062] The system and method according to any of the preceding clauses, wherein the plurality of acoustic features includes steady-state features, and the associated operating conditions to which the steady-state features are indexed include steady-state operating conditions of the turbine engine, and the steady-state operating conditions include the running average of the previous acoustic data output from the first acoustic sensor during the current steady-state operation of the turbine engine.

[0063] The system and method according to any of the preceding clauses, wherein the preset threshold is at least three decibels.

[0064] The system and method according to any of the preceding clauses, wherein the first acoustic sensor converts a portion of the sound having a frequency in the range of 25 Hz to 250 Hz emitted from the gearbox into the acoustic data.

[0065] The system and method according to any of the preceding clauses, wherein the first acoustic sensor converts a portion of the sound having a frequency in the range of 20 Hz to 20 kHz emitted from the gearbox into the acoustic data.

[0066] The system and method according to any of the preceding clauses, wherein the first acoustic sensor converts a portion of the sound having a frequency in the range of 300 Hz to 3 kHz emitted from the gearbox into the acoustic data.

[0067] The system and method according to any of the preceding clauses, wherein the plurality of acoustic features include respective time-domain data output by the first acoustic sensor during one or more test operations of the turbine engine, wherein the acoustic data includes current time-domain data corresponding to the sound emitted from the gearbox, and wherein the processor is further configured to compare the current time-domain data with the respective time-domain data of one of the plurality of acoustic features to generate the comparison result.

[0068] The system and method according to any of the preceding clauses, wherein the plurality of acoustic features include respective frequency-domain data generated from the output of the first acoustic sensor during one or more test operations of the turbine engine, wherein the acoustic data includes current time-domain data corresponding to the sound emitted from the gearbox, and wherein the processor is further configured to transform the current time-domain data into current frequency-domain data and compare the current frequency-domain data with the respective frequency-domain data of one of the plurality of acoustic features to generate the comparison result.

[0069] The system and method according to any of the preceding clauses, wherein the indicator is activated in response to identifying the presence of the maintenance condition.

[0070] The system and method according to any of the preceding clauses, wherein the indicator includes a maintenance message and / or notification.

[0071] The system and method according to any of the preceding clauses, wherein the message or notification is transmitted to and displayed on a display in the cockpit of the aircraft to notify the pilot of the problem.

[0072] The system and method according to any of the preceding clauses, wherein the message or notification is transmitted to one or more ground sources immediately or upon the next landing of the aircraft to trigger a maintenance process to correct the maintenance condition.

[0073] The system and method according to any of the preceding clauses, wherein the indicator includes a light in the cockpit or elsewhere on the aircraft, and the light is activated when the maintenance condition is identified as present.

[0074] The system and method according to any of the preceding clauses, wherein the indicator is configured to output or indicate different severities depending on the magnitude, duration, and number of differences detected between the acoustic data from the first acoustic sensor and / or the one or more additional acoustic sensors and the plurality of acoustic signatures.

[0075] The system and method according to any of the preceding clauses, wherein the maintenance condition is identified as present once the deviation has been present for at least a minimum time period.

[0076] The system and method according to any of the preceding clauses, wherein the one or more test operations include an engine break - in or power assurance procedure performed after an initial build of the turbine engine or after a subsequent maintenance action on the turbine engine.

[0077] The system and method according to any of the preceding clauses, wherein the plurality of acoustic signatures includes frequency - domain data and / or time - domain data generated from one or more acoustic sensors of a turbine engine different from the turbine engine in which the first acoustic sensor is located.

[0078] The system and method according to any of the preceding clauses, wherein the plurality of acoustic signatures is populated with additional characteristics of the operating conditions of the turbine engine for which no associated characteristics are yet stored in the memory.

[0079] The system and method according to any of the preceding clauses, wherein the population of the plurality of acoustic signatures is completed during a first stable flight operation after installation of the turbine engine on the aircraft or after maintenance of the turbine engine, the first stable flight operation specifying a minimum time period to allow the turbine engine to reach thermal equilibrium.

Claims

1. A turbine engine gearbox monitoring system, characterized in that, The system includes: A first acoustic sensor located near a gearbox of a turbine engine, the first acoustic sensor being configured to output acoustic data representative of sound emitted from the gearbox; A processor operatively connected to the first acoustic sensor; and A memory operatively connected to the processor, the memory storing therein a plurality of acoustic signatures indexed according to associated operating conditions of the turbine engine, wherein the processor is configured to: Receive the acoustic data from the first acoustic sensor; Identify a current operating condition of the turbine engine; Select one of the plurality of acoustic signatures in the memory based on the current operating condition; Use the selected one of the plurality of acoustic signatures and the acoustic data to generate a comparison result; and Identify a maintenance condition of the gearbox when the comparison result indicates a deviation greater than or equal to a preset threshold.

2. The system according to claim 1, characterized in that, Wherein, The first acoustic sensor converts a portion of the sound emitted from the gearbox having a frequency in the range of 25 Hz to 250 Hz into the acoustic data.

3. The system according to claim 1, characterized in that, Wherein, The first acoustic sensor converts a portion of the sound emitted from the gearbox having a frequency in the range of 20 Hz to 20 kHz into the acoustic data.

4. The system according to claim 1, characterized in that, Wherein, The first acoustic sensor converts a portion of the sound emitted from the gearbox having a frequency in the range of 300 Hz to 3 kHz into the acoustic data.

5. The system according to claim 1, wherein Wherein, The plurality of acoustic signatures include respective time-domain data output by the first acoustic sensor during one or more test operations of the turbine engine, wherein the acoustic data includes current time-domain data corresponding to the sound emitted from the gearbox, and wherein the processor is further configured to compare the current time-domain data with the respective time-domain data of the selected one of the plurality of acoustic signatures to generate the comparison result.

6. The system according to claim 1, wherein Wherein, The plurality of acoustic signatures include respective frequency-domain data generated from the output of the first acoustic sensor during one or more test operations of the turbine engine, wherein the acoustic data includes current time-domain data corresponding to the sound emitted from the gearbox, and wherein the processor is further configured to transform the current time-domain data into current frequency-domain data and compare the current frequency-domain data with the respective frequency-domain data of the selected one of the plurality of acoustic signatures to generate the comparison result.

7. The system according to claim 1, wherein Further includes one or more additional acoustic sensors different from the first acoustic sensor, the one or more additional acoustic sensors being located near the gearbox of the turbine engine and being configured to output additional respective acoustic data in response to the sound emitted from the gearbox, wherein the plurality of acoustic signatures are further indexed according to an association with one of the first acoustic sensor or the one or more additional acoustic sensors, and wherein the processor is further configured to: Receive the additional respective acoustic data from the one or more additional acoustic sensors; Additionally select the one of the plurality of acoustic features in the memory based on the association with the first acoustic sensor; Select additional acoustic features of the plurality of acoustic features in the memory based on the associations with the one or more additional acoustic sensors and the current operating conditions of the turbomachine; And Generate the comparison result using the additional acoustic features of the selected plurality of acoustic features and the additional respective acoustic data.

8. The system according to claim 7, wherein Wherein, the processor is configured to generate the comparison result by comparing the one of the selected plurality of acoustic features with the acoustic data or a transformation thereof and comparing the additional acoustic features of the selected plurality of acoustic features with the additional respective acoustic data or a transformation thereof, wherein when the acoustic data or a transformation thereof deviates from the one of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, the comparison result indicates the deviation greater than or equal to the preset threshold, and wherein when the additional respective acoustic data or a transformation thereof deviates from the additional acoustic features of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, the comparison result also indicates the deviation greater than or equal to the preset threshold.

9. The system according to claim 7, wherein Wherein, the processor is configured to generate the comparison result by comparing the one of the selected plurality of acoustic features with the acoustic data or a transformation thereof and comparing the additional acoustic features of the selected plurality of acoustic features with the additional respective acoustic data or a transformation thereof, wherein when the acoustic data or a transformation thereof deviates from the one of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold and when the additional respective acoustic data or a transformation thereof deviates from the additional acoustic features of the selected plurality of acoustic features at one or more comparison points by at least the preset threshold, the comparison result indicates the deviation greater than or equal to the preset threshold.

10. The system according to claim 1, wherein, Wherein, when the average difference between the one of the selected plurality of acoustic features and the acoustic data or a transformation thereof is greater than or equal to the preset threshold, the comparison result indicates the deviation greater than or equal to the preset threshold.

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