Monitoring anti-leak valves in jet engines

Abstract

Method for monitoring a leakproof valve (110) of a circuit (11) supplying oil between an oil reservoir (10) of a jet engine and an element (2) to be lubricated, comprising the steps of: - measuring (E1, E3) an oil level value (EOL 停止 , EOL 空转 ) in the reservoir at the beginning of the start of the jet engine and at the end of the start of the jet engine, - calculating (E4) a difference value (EOL 测量 ) between the measured oil levels to form a measured variation value of the oil level, - measuring (E2) an oil temperature value (EOT 启动 ), - determining (E5) an estimated variation value (EOL 模型 ) of the oil level in the reservoir as a function of said oil temperature, - calculating (E6) a difference value (ΔEOL) between said measured variation value and said estimated variation value of the oil level for said measured temperature, - comparing (E7) the calculated difference value with a detection threshold, - activating (E9) an alert as a function of the comparison result.

Description

Technical Field

[0001] This invention generally relates to systems for lubricating jet engines. More specifically, this invention relates to monitoring a leak-proof valve in the circuit supplying oil between the oil reservoir of a jet engine and the components to be lubricated. Background Technology

[0002] The jet engine includes a lubrication system directly mounted on the accessory gearbox (AGB). This lubrication system includes an oil reservoir, an oil supply circuit for distributing oil to the components of the jet engine to be lubricated, and an oil recovery circuit for ensuring the return of oil to the reservoir. A series of pumps, actuators, and sensors enable oil to flow from the reservoir to the components of the jet engine via the supply circuit and to flow back from the jet engine to the reservoir via the recovery circuit.

[0003] The lubrication system has two main functions: to lubricate and cool the components of the jet engine, and to maintain the oil temperature at an acceptable level. Comprehensive monitoring of the lubrication system is performed by control software that obtains data from oil temperature and pressure sensors located on the accessory gearbox, and from an oil level sensor located in the oil reservoir.

[0004] The circuit used to supply oil between the components to be lubricated and the oil reservoir in a jet engine includes an anti-leak valve (ALV). The anti-leak valve is an on / off type: it opens according to operating conditions and is not controlled by the jet engine computer. The purpose of the anti-leak valve is to prevent oil in the reservoir from draining into the jet engine's accessory gearbox under gravity when the jet engine is stopped.

[0005] In the event of a leak-proof valve failure, the valve ceases to function, which could negatively impact the jet engine.

[0006] In fact, when the jet engine stops, the various pumps in the lubrication system's supply and recovery circuits are not operating, and without anti-leak valves, oil drains from the oil reservoir into the jet engine's accessory transmission housing. This presents a problem, particularly the risk that the empty reservoir may not be filled with oil during maintenance operations, leading to oil spillage from the jet engine. Oil spillage can have detrimental effects on the jet engine.

[0007] Therefore, it is necessary to monitor the anti-leak valve in the circuit that supplies oil between the lubricated components and the oil reservoir of the jet engine in order to detect any malfunctions of the anti-leak valve. Summary of the Invention

[0008] The object of this invention is to solve the problems of the prior art by providing a method for monitoring the oil supply circuit between the oil reservoir and the lubricated components of a jet engine, characterized in that the method includes the following steps:

[0009] - Indicates that the oil level in the reservoir is measured at the start of the jet engine startup and at the end of the jet engine startup, respectively.

[0010] - Calculate the difference between the oil level in the reservoir at the start of the jet engine startup and at the end of the jet engine startup to form a measured change value of the oil level in the reservoir.

[0011] -Indicates the measured oil temperature value

[0012] - Determine the estimated change in oil level in the storage section based on the oil temperature value.

[0013] - Calculate the difference between the measured change in oil level in the storage compartment and the estimated change in oil level in the storage compartment for the measured temperature value.

[0014] - Compare the calculated difference with the detection threshold.

[0015] - If the calculated difference is lower than the detection threshold, an alarm is activated.

[0016] Thanks to this invention, leak-proof valves can be monitored in circuits supplying oil between the lubricated components and the oil reservoir in a jet engine without the need for a position sensor. Such sensors would otherwise impact the weight, cost, and complexity of the product.

[0017] This invention also avoids preventative maintenance operations to ensure the proper operation of the leak-proof valve, which would significantly increase maintenance limitations and not be part of a possible operational solution.

[0018] According to a preferred feature, the start-up and end-up of the jet engine are detected based on the speed measurement of the high-pressure shaft of the jet engine.

[0019] According to a preferred feature, the alarm is activated if the comparison result of a first predetermined number of jet engine starts for a second predetermined number of recent jet engine starts is lower than the detection threshold.

[0020] The present invention also relates to a device for monitoring a leak-proof valve in a circuit supplying oil between an oil reservoir and a component to be lubricated in a jet engine, characterized in that the device comprises:

[0021] - A sensor capable of measuring the oil level in the oil reservoir at the start of the jet engine's startup and at the end of the jet engine's startup, respectively.

[0022] - A sensor capable of measuring oil temperature.

[0023] - A calculator capable of calculating the difference between the oil level value in the storage compartment at the start of the jet engine and at the end of the jet engine's start, to form a measured change value of the oil level in the storage compartment, determining an estimated change value of the oil level in the storage compartment based on the oil temperature value, calculating the difference between the measured change value of the oil level in the storage compartment and the estimated change value of the oil level in the storage compartment for the measured temperature value, comparing the calculated difference with a detection threshold, and activating an alarm if the calculated difference is lower than the detection threshold.

[0024] The present invention also relates to a jet engine equipped with a device as described above for monitoring a leak-proof valve in the oil supply circuit between the oil reservoir and the components to be lubricated in the jet engine.

[0025] The present invention also relates to an aircraft equipped with a jet engine as described above.

[0026] The device, jet engine, and aircraft have similar advantages to those previously described.

[0027] In one particular embodiment, the steps of the method according to the invention are implemented by computer program instructions.

[0028] Therefore, another object of the present invention is a computer program on an information medium, which can be implemented in a computer, the program comprising instructions adapted to implement the steps of the method as described above.

[0029] Another object of the present invention is an information medium readable by a computer, the information medium comprising computer program instructions adapted to implement the steps of the method described above. Attached Figure Description

[0030] Other features and advantages will become apparent from the following description of preferred embodiments, given only by non-limiting example, with reference to the accompanying drawings:

[0031] Figure 1 A jet engine is shown with a circuit equipped with a leak-proof valve for monitoring the circuit of the supply lubrication system, according to an embodiment of the present invention.

[0032] Figure 2A method for monitoring a leak-proof valve in a circuit supplying a lubrication system, according to an embodiment of the present invention, is shown.

[0033] Figure 3 The change in oil level in the reservoir is shown during jet engine startup.

[0034] Figure 4 The diagram shows the oil level in the reservoir related to oil temperature during jet engine startup.

[0035] Figure 5 The oil temperature-related indicator values ​​generated according to the present invention are shown.

[0036] Figure 6 It shows Figure 5 The distribution of the indicated values ​​is shown.

[0037] Figure 7 The indicated values ​​determined for jet engine startup and the distribution of these indicated values ​​are shown.

[0038] Identical, similar or equivalent parts in each figure have the same reference numerals to facilitate transition from one figure to another.

[0039] The parts shown in the accompanying drawings are not necessarily to a uniform scale in order to make the drawings easier to read.

[0040] Various options (alternative embodiments and implementations) should be understood as not mutually exclusive and can be combined with each other. Detailed Implementation

[0041] according to Figure 1 In the preferred embodiment shown, the jet engine includes a lubrication system 1 for lubricating the components 2 of the jet engine that are to be lubricated.

[0042] The lubrication system includes: an oil reservoir 10, an oil supply circuit 11 for distributing oil to the components of the jet engine to be lubricated, and an oil recovery circuit 12 for ensuring that oil is returned to the reservoir. The jet engine also includes an accessory transmission housing (not shown).

[0043] More specifically, there is interest in the leak-proof valve (ALV) 110 of the oil supply circuit 11, which is disposed between the storage section 10 and the assembly 2 of the component to be lubricated.

[0044] The anti-leakage valve is an on / off type. Its purpose is to prevent oil in the fuel reservoir from flowing into the engine's accessory transmission box under gravity when the jet engine is stopped.

[0045] The jet engine includes sensors, particularly an oil temperature sensor 3 placed in the accessory transmission box, a high-pressure shaft speed sensor 4 of the jet engine, and an oil level sensor 5 placed in the oil storage compartment 10.

[0046] Only elements that help to understand the invention have been described. Other elements of the jet engine and its lubrication system are known to those skilled in the art and will not be described in detail here.

[0047] The jet engine includes a circuit 6 for monitoring a leak-proof valve 110 in the oil supply circuit. The circuit for monitoring the leak-proof valve may be a dedicated calculator or a sub-component of a calculator that comprehensively monitors the oil circuit via control software that receives data from sensors.

[0048] The monitoring loop 6 has a general computer structure. Specifically, the monitoring loop includes a processor 60, a memory 61, an input interface 62, and an output interface 63 that execute a computer program implementing the method according to the present invention.

[0049] These different components are typically connected via bus 65.

[0050] Input interface 62 is connected to the corresponding output terminals of sensors 3, 4 and 5, and is used to receive variables measured by these sensors.

[0051] Processor 60 executes the following disclosed processing procedure. This processing procedure is executed in the form of code instructions from a computer program, which are stored in memory 61 before being executed by processor 60.

[0052] The memory 61 stores the measured values ​​and calculated values.

[0053] Output interface 63 is connected to alarm system 7, which may or may not be integrated into monitoring loop 6, and is activated based on monitoring results. Alarm system 7 is conventional and includes an interface for operators to issue alarms to it.

[0054] Figure 2 An embodiment of a method for monitoring a leak-proof valve 110 of an oil supply circuit 11 for a jet engine is shown. The method includes steps E0 to E9 performed by a monitoring circuit 6 during jet engine startup.

[0055] Step E0 is the standby step, in which the jet engine stops. When the jet engine is started, the next steps E1 through E9 are executed.

[0056] During jet engine startup, in the absence of leakage in the anti-leak valve 110 of the oil supply circuit 11, the change in oil quantity in the component 2 of the jet engine to be lubricated is a reproducible phenomenon, in which only the change in oil temperature from one flight to another causes slight dispersion.

[0057] In the event of a leak in the anti-leak valve 110 of the oil supply circuit 11, oil flows between the reservoir and the accessory transmission box when the jet engine stops. This results in an abnormally high oil level in assembly 2 of the jet engine's components to be lubricated before and at the start of startup. In this situation, the change in oil level in assembly 2 of the jet engine's components to be lubricated during jet engine startup will therefore differ from the changes typically encountered.

[0058] Step E1 is to indicate the oil level EOL in the measuring reservoir 10 when the jet engine is started. 停止 (EOL stop The oil level in the storage compartment 10 is measured by sensor 5. The total amount of oil in the jet engine is approximately equal to the sum of the amount of oil present in the storage compartment 10 and the amount of oil present in assembly 2 of the jet engine's components to be lubricated. Therefore, the measured value of the oil level in the storage compartment 10 is an indication of the amount of oil present in assembly 2 of the jet engine's components to be lubricated.

[0059] The start-up of a jet engine is detected by the speed N2 of the high-pressure shaft. In fact, during the start-up process, the speed N2 of the high-pressure shaft varies between zero (at the beginning of start-up) and a speed characterizing idle power (at the end of start-up). This idle power speed is, for example, equal to 70% of the jet engine's maximum power.

[0060] The speed N2 of the high-pressure shaft is measured by sensor 4.

[0061] The start-up of a jet engine is detected by the zero speed N2 of the high-pressure shaft of the jet engine.

[0062] The result of step E1 is the measured oil level (EOL) in the reservoir 10 when the jet engine is started. 停止 .

[0063] The next step, E2, is to instruct the oil temperature to be measured via the oil temperature sensor 3.

[0064] The result of step E2 is the temperature measurement value EOT during jet engine startup. 启动 (EOT start ).

[0065] The next step, E3, is to measure the oil level (EOL) in the storage compartment 10 at the end of the jet engine's startup. 空转 (EOLralenti Once again, the oil level in the storage compartment is measured by sensor 5 and is a representation of the amount of oil present in component 2 of the jet engine's lubricated parts.

[0066] The start-up of a jet engine is determined by the fact that the N2 of the high-pressure shaft of the jet engine equals the idle speed of the jet engine.

[0067] The result of step E3 is the measured oil level (EOL) in the reservoir 10 at the end of the jet engine's start-up. 空转 .

[0068] Alternatively, the measurement timing during startup is different and is determined by other velocity values ​​N2 of the high-pressure shaft of the jet engine.

[0069] Figure 3 The diagram shows the change in oil level EOL in the storage section 10 with the speed N2 of the high-pressure shaft of the jet engine during jet engine startup (i.e., from the start of startup to the end of startup). Figure 3 An example of nominal operation is shown when the anti-leakage valve 110 is in normal operation.

[0070] The speed N2 of the high-pressure shaft of the jet engine varies between zero speed and idle speed, and is expressed as a percentage of the jet engine's maximum power.

[0071] In the event of a leak in the anti-leak valve 110, the following warning will be issued upon startup: oil spillage exists in assembly 2 of the jet engine's components to be lubricated, resulting in an abnormal distribution of oil within the jet engine. Upon completion of startup, operation will stabilize as the oil recovery pump in the oil recovery circuit recovers all or part of the oil initially stored in assembly 2 of the jet engine's components to be lubricated.

[0072] The next step, E4, is to calculate an indicated value equal to the measured oil level (EOL) in the reservoir at the start of jet engine startup. 停止 And the measured oil level (EOL) in the reservoir at the end of jet engine startup. 空转 The difference between them:

[0073] EOL 测量 =EOL 停止 -EOL 空转 (E1)

[0074] This indication value represents the measured change in oil level in the reservoir. Its purpose is to detect any abnormal operation of the anti-leakage valve 110 during startup, based on the change in oil level in the reservoir between the start of startup (zero engine power) and the end of startup (engine idling).

[0075] Therefore, the result of step E4 is the indicator value EOL. 测量 (EOL Measure The value of ).

[0076] Simultaneous with or after step E4, step E5 calculates the estimated change in oil level in storage unit 10 based on the oil temperature at the time the jet engine is started. The oil temperature is measured by sensor 3.

[0077] The inventors noted that the dispersion in the oil level in the reservoir observed when starting a jet engine was primarily related to oil temperature. To improve the accuracy of these indicated values, oil temperature was taken into account.

[0078] Figure 4 The oil level EOL in the reservoir 10 during jet engine startup is shown, and it is related to the oil temperature.

[0079] There is a significant correlation between the oil level in the reservoir during jet engine startup and the oil temperature at startup.

[0080] Therefore, the oil temperature change during startup can be simulated by creating a model of the oil level in the reservoir when the jet engine is started, in the following form:

[0081] EOL 模型 =α×EOT 启动 +b(E2)

[0082] Among them, EOT 启动 This represents the oil temperature at the start of the jet engine, and a and b are constants.

[0083] Therefore, the result of step E5 is the oil temperature EOT measured in the storage unit 10 when the jet engine is started. 启动 Estimated oil level (EOL) 模型 (EOL Modèle ).

[0084] Steps E4 and E5 are followed by step E6, in which the value EOL calculated in step E4 is... 测量 The value EOL calculated in step E5 模型 The difference ΔEOL between them is calculated:

[0085] ΔEOL=EOL 测量 -EOL 模型 (E3)

[0086] The difference ΔEOL is an indication value that eliminates the influence of temperature.

[0087] Therefore, the result of step E6 is the value of the indicator value ΔEOL.

[0088] Figure 5 The difference ΔEOL in relation to oil temperature is shown in a series of measurements performed on a given jet engine. This is achieved through... Figure 5 and Figure 4 In comparison, it is worth noting that the indicated value is centered at zero regardless of the temperature within the operating range.

[0089] Figure 6 The distribution of the indicated value ΔEOL in a series of measurements performed on a given jet engine is shown. This distribution can be approximated by a not-very-discrete Gaussian distribution.

[0090] The next step, E7, is to perform a test to determine if the oil level in the storage compartment is normal, i.e., whether the anti-leakage valve is working properly.

[0091] Therefore, the value of the indication value ΔEOL determined in the previous step will be compared with the detection threshold (e.g., ...). Figure 7 As shown, the detection threshold is equal to -2) for comparison. The comparison result is stored.

[0092] exist Figure 7 On the left side of the graph, each point above the detection threshold corresponds to an indication value ΔEOL for starting the jet engine through a healthy leak-proof valve, while each point below the detection threshold corresponds to an indication value ΔEOL for starting the jet engine through a faulty leak-proof valve. The right side of the graph shows the distribution of the points on the left side.

[0093] If the indicated value ΔEOL is higher than the detection threshold, the oil level is normal, and the already described step E0 is performed after step E7.

[0094] Conversely, if the indicated value ΔEOL is lower than the detection threshold, the oil level is abnormal, and step E8 is performed after step E7. Step E8 is a test to determine whether N abnormal oil levels have been detected in the most recent M jet engine starts, where N is a first predetermined number, for example, equal to three, and M is a second predetermined number greater than N, for example, equal to five.

[0095] If the response is negative, then proceed to the previously described step E0 after step E8.

[0096] Conversely, if the response is positive, it means that the abnormal oil level detection is a recurring phenomenon. Step E9, which triggers an alarm, then follows step E8. For example, this alarm might be a message for maintenance personnel of a jet engine.

Claims

1. A method for monitoring a leak-proof valve (110) of a circuit (11) supplying oil between an oil reservoir (10) and a component (2) to be lubricated in a jet engine, characterized in that, The method includes the following steps: - Measure the oil level (EOL) in the oil reservoir (E1, E3) at the start of the jet engine startup and at the end of the jet engine startup, respectively. 停止 EOL 空转 ), - Calculate (E4) the first difference (EOL) between the oil level in the oil reservoir at the start of the jet engine startup and at the end of the jet engine startup. 测量 (), to generate a measured change in the oil level in the oil storage section, - Measure the (E2) oil temperature value (EOT) 启动 ), - Determine the estimated change in oil level (EOL) in the oil storage section based on the oil temperature value (E5). 模型 ), - Calculate (E6) the second difference (ΔEOL) between the measured change in oil level in the oil storage unit and the estimated change in oil level in the oil storage unit for the measured temperature value. - Compare the calculated second difference with the detection threshold (E7). - If the calculated second difference is lower than the detection threshold, then an (E9) alarm is activated.

2. The method according to claim 1, wherein, The start-up and end-up of the jet engine are detected based on the speed measurement (N2) of the high-pressure shaft of the jet engine.

3. The method according to claim 1 or 2, wherein, The alarm is activated if the comparison result of the first predetermined number (N) jet engine starts among the most recent second predetermined number (M) jet engine starts is lower than the detection threshold.

4. A device for monitoring a leak-proof valve (110) of a circuit (11) supplying oil between an oil reservoir (10) and a component (2) to be lubricated in a jet engine, characterized in that, The device includes: - Sensor (5), which is capable of measuring the oil level in the oil storage section (10) at the start of the jet engine and at the end of the start of the jet engine, respectively. - A sensor capable of measuring oil temperature (3). - Calculator (6), the calculator is capable of calculating a first difference between the oil level value in the oil reservoir at the start of the jet engine and at the end of the jet engine start to form a measured change value of the oil level in the oil reservoir, determining an estimated change value of the oil level in the oil reservoir based on the oil temperature value, calculating a second difference between the measured change value of the oil level in the oil reservoir and the estimated change value of the oil level in the oil reservoir for the measured temperature value, comparing the calculated second difference with a detection threshold, and activating an alarm if the calculated second difference is lower than the detection threshold.

5. A jet engine equipped with a device according to claim 4 for monitoring a leak-proof valve in the oil supply circuit between the oil reservoir of the jet engine and the components to be lubricated.

6. An aircraft equipped with a jet engine according to claim 5.

7. A computer program product comprising a computer program, the computer program including instructions that, when executed by a computer, are used to perform the steps of the method according to any one of claims 1 to 3.

8. A recording medium readable by a computer, the recording medium storing a computer program, the computer program including instructions for performing the steps of the method according to any one of claims 1 to 3.

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