Engine fuel oil leakage detection method based on multiple engines of unmanned aerial vehicle

Abstract

The invention belongs to the technical field of engines, and provides an engine fuel oil leakage detection method based on multiple engines of an unmanned aerial vehicle, which comprises the following steps: acquiring parameters corresponding to at least three engines, acquiring corresponding parameters from the parameters, and calculating to obtain a first fuel oil pressure extreme value, a second fuel oil pressure extreme value and a third fuel oil pressure extreme value; the first fuel pressure extreme value meets a first condition, the second fuel pressure extreme value and the third fuel pressure extreme value respectively meet a second condition, the existence of the fuel leakage risk is preliminarily confirmed, the inlet temperature of each engine turbine is calculated by obtaining corresponding parameters, the inlet temperature of the first engine turbine meets a third condition, and the inlet temperature of the second engine turbine meets a fourth condition. And when the inlet temperatures of the other two power turbines meet a fourth condition, it is confirmed that the fuel oil leakage risk exists again, the corresponding parameters are obtained, the first oil supply amount and the second oil supply amount are obtained through calculation, and when the first oil supply amount and the second oil supply amount meet a fifth condition, it is confirmed that fuel oil leakage exists in the first engine. Accurate monitoring of engine fuel oil leakage is achieved, and safety is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engines, and in particular relates to a method for detecting fuel leakage of an engine based on multiple engines of an unmanned aerial vehicle. Background Art

[0002] The fuel system of an aircraft engine is composed of many pipes, valves, etc. It is a highly integrated system. After the system is installed on the aircraft, the engine will be subjected to vibrations of different frequencies, which may cause damage and leakage of the fuel system. Fuel leakage is a very harmful failure mode. If it is not discovered in time, it may cause the fuel to fail to enter the engine body and burn according to the preset amount, affecting the working stability of the engine, and even causing serious consequences such as fire and shutdown.

[0003] In order to monitor the fuel flow, a metering needle is installed in the engine fuel system. The fuel flow is automatically calculated according to the angle of the needle. The control system also sets the fault mode and countermeasures of the needle, as follows:

[0004] Metering oil needle extreme failure mode: Metering oil needle <-30°

[0005] Metering oil needle change rate fault mode: |Δ metering oil needle|>60° / 24ms (milliseconds)

[0006] However, the above failure modes and countermeasures are all aimed at the metering needle itself. The numerical settings are very extreme. They will only be triggered when the needle itself fails or the fuel flow changes extremely abnormally. Under normal circumstances, the aircraft will not be triggered when operating at high and low temperatures or at the maximum flight altitude. Therefore, it is also impossible to detect the failure of slow fuel leakage.

[0007] In order to avoid the above situation, in addition to the sensors built into the engine, many monitoring devices are installed on the vehicle platform to monitor the engine status during the engine bench test. The number of monitoring devices is often higher than the sensors built into the engine. The fuel flow meter on the vehicle platform is one of them. By comparing the fuel flow on the vehicle platform with the metering value of the engine oil needle, the fuel leakage fault is found. However, in the case of installation, except for the sensors built into the engine, most of the monitoring equipment on the vehicle platform will be streamlined, and the fuel leakage monitoring means of the vehicle platform cannot be adopted, resulting in the engine fuel leakage being in an unmonitored state, which increases the risk. Summary of the invention

[0008] In view of the above problems, the present invention proposes a method for detecting fuel leakage of an engine based on multiple engines of a UAV, the method comprising:

[0009] Acquiring normal parameters, current parameters and parameter benchmarks corresponding to at least three engines;

[0010] Obtain the corresponding pressure parameters from the normal parameters and the current parameters to calculate the first engine fuel pressure extreme value, as well as the second and third engine fuel pressure extreme values. The first engine fuel pressure extreme value satisfies the first condition, and the second and third engine fuel pressure extreme values respectively satisfy the second condition, preliminarily confirming that there is a risk of fuel leakage in the first engine;

[0011] Obtain the corresponding temperature parameters from the normal parameters and the current parameters to calculate the inlet temperature of the power turbine for each engine. The inlet temperature of the power turbine of the first engine satisfies the third condition, and the inlet temperatures of the power turbines of the other two engines respectively satisfy the fourth condition, further confirming that there is a risk of fuel leakage in the first engine;

[0012] Obtain the corresponding parameters from the normal parameters, the current parameters and the parameter reference to calculate the first fuel supply amount and the second fuel supply amount. When the first fuel supply amount and the second fuel supply amount respectively satisfy the fifth condition, it is confirmed that there is fuel leakage in the first engine.

[0013] Optionally, obtaining the first engine fuel pressure extreme value by obtaining the corresponding pressure parameters from the normal parameters and the current parameters includes:

[0014] Obtain the first engine pressure difference based on the difference between the current first engine fuel pressure extreme value and the normal first engine fuel pressure extreme value;

[0015] The ratio of the first engine pressure difference to the normal first engine fuel pressure extreme value gives the first engine fuel pressure extreme value.

[0016] Optionally, obtaining the second and third engine fuel pressure extreme values by obtaining the corresponding pressure parameters from the normal parameters and the current parameters includes:

[0017] Obtain the second engine pressure difference based on the difference between the current second engine fuel pressure extreme value and the normal second engine fuel pressure extreme value;

[0018] The ratio of the second engine pressure difference to the normal second engine fuel pressure extreme value gives the second engine fuel pressure extreme value;

[0019] Obtain the third engine pressure difference based on the difference between the current third engine fuel pressure extreme value and the normal third engine fuel pressure extreme value;

[0020] The ratio of the third engine pressure difference to the normal third engine fuel pressure extreme value gives the third engine fuel pressure extreme value.

[0021] Optionally, the first engine fuel pressure extreme value satisfies the first condition, including:

[0022]

[0023] Among them, P-1当前极值 Indicates the current extreme value of the fuel pressure of the first engine, P -1正常极值 Indicates the normal extreme value of the fuel pressure of the first engine.

[0024] Optionally, the extreme values of the fuel pressures of the second and third engines respectively satisfy the second condition, including:

[0025]

[0026] P -2当前极值 Indicates the current extreme value of the fuel pressure of the second engine, P -2正常极值 Indicates the normal extreme value of the fuel pressure of the second engine, P -3当前极值 Indicates the current extreme value of the fuel pressure of the third engine, P -3正常极值 Indicates the normal extreme value of the fuel pressure of the third engine.

[0027] Optionally, the inlet temperatures of the power turbines of each engine are calculated by obtaining the corresponding temperature parameters from the normal parameters and the current parameters, including:

[0028] The inlet temperatures of the power turbines of each engine are obtained based on the difference between the average value of the current inlet temperatures of the power turbines of each engine and the average value of the normal inlet temperatures of the power turbines of each engine, where the average value of the normal inlet temperatures of the power turbines of each engine is the average value of the normal inlet temperatures of the power turbines of each engine within the previous 3 s compared to the current inlet temperatures of the power turbines of each engine.

[0029] Optionally, the inlet temperature of the first power turbine satisfies the third condition, including:

[0030] |Tt45 -1当前 -Tt45 -1平均 |≥8℃

[0031] where Tt45 -1当前 Indicates the current inlet temperature of the first power turbine, Tt45 -1平均 Indicates the average value of the normal inlet temperatures of the first power turbine.

[0032] Optionally, the inlet temperatures of the power turbines of the other two engines respectively satisfy the fourth condition, including:

[0033] |Tt45 -2当前 -Tt45 -2平均 |<6℃

[0034] |Tt45 -3当前 -Tt45 -3平均 |<6℃

[0035] where Tt45 -2当前 Indicates the current inlet temperature of the first power turbine, Tt45 -2平均 Indicates the average value of the normal inlet temperatures of the first power turbine, Tt45-3当前 Denoted as the current inlet temperature of the first power turbine, Tt45 -3平均 Denotes the average value of the normal inlet temperature of the first power turbine.

[0036] Optionally, the first fuel supply amount and the second fuel supply amount are calculated according to the corresponding parameters obtained from the normal parameters, the current parameters, and the parameter reference, including:

[0037] Calculate the fuel amount A required for each 1°C increase of the first engine according to the relationship between the inlet temperature of the power turbine and the engine fuel supply amount;

[0038] Re-confirm the current fuel supply amount of the first engine, and the specific steps are as follows:

[0039] Wf -1当前 = Wf -1正常 +(Tt45 -1当前 - Tt45 -1正常 )×A

[0040] Where, Wf -1正常 is the normal fuel supply amount of the first engine, Tt45 -1当前 is the current inlet temperature of the first power turbine, Tt45 -1正常 is the normal inlet temperature of the first power turbine, and A is the fuel amount;

[0041] Calculate the first fuel supply amount and the second fuel supply amount according to the re-confirmed current fuel supply amount of the first engine, and the specific calculation steps are as follows:

[0042]

[0043] Wf1 当前变化 - Wf1 基准变化 = the first fuel supply amount

[0044]

[0045] Wf2 当前变化 - Wf2 基准变化 = the first fuel supply amount

[0046] Where, Wf1 当前变化 is the current fuel supply change amount between the first engine and the second engine, Wf1 基准变化 is the reference fuel supply change amount between the first engine and the second engine, Wf -1当前 is the current fuel supply amount of the first engine, Wf -2当前 is the current fuel supply amount of the second engine, Wf -3当前 is the current fuel supply amount of the third engine, Wf -1基准 is the reference fuel supply amount of the first engine, Wf -2基准 is the reference fuel supply amount of the second engine, Wf -3基准 is the reference fuel supply amount of the third engine.

[0047] Optionally, the first fuel supply amount and the second fuel supply amount respectively satisfy a fifth condition, including:

[0048]

[0049] Wf -1当前 is the current fuel supply amount of the first engine, Wf -2当前 is the current fuel supply amount of the second engine, Wf -3当前 is the current fuel supply amount of the third engine, Wf -1基准 is the reference fuel supply amount of the first engine, Wf -2基准 is the reference fuel supply amount of the second engine, Wf -3基准 is the reference fuel supply amount of the third engine.

[0050] The present invention has the following advantages compared with the prior art:

[0051] By comparing the fuel pressure, the inlet temperature of the power turbine, and the fuel supply amount of at least three engines to determine whether there is a leak. Specifically, first, the fuel pressure of each engine is used to meet the corresponding conditions for a preliminary confirmation of the risk of oil leakage. Then, when the inlet temperature of the power turbine of each engine meets the corresponding conditions, the risk of oil leakage is further confirmed. Finally, the fuel supply amount is used to confirm that there is fuel leakage in the engine, avoiding the occurrence of missed inspections, achieving accurate monitoring of engine fuel leakage, improving the speed of detecting oil leakage, and enhancing safety.

[0052] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structure pointed out in the specification and the drawings. Brief Description of the Drawings

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1 Shows a schematic flow chart of the method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle in an embodiment of the present invention. Detailed Embodiments

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0056] As Figure 1 shown, the present invention provides a method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle (UAV). The method includes:

[0057] Step S10, obtaining normal parameters, current parameters, and parameter references corresponding to at least three engines. It should be noted that in this embodiment, a 3-engine UAV is taken as an example. Assuming that the first engine has fuel leakage, this method is described based on this, and fuel leakage of other engines can be judged according to this method. The main parameters measured by the sensors of the 3 engines are defined as follows in Table 1:

[0058] Table 1

[0059]

[0060]

[0061] Specifically, before installation, the main bench performance data of the 3 engines are input into the control system as the reference performance, mainly including Tt45, Wf, and P under different gas generator speeds Ng (such as 80% Ng, 85% Ng, 90% Ng, 95% Ng, 100% Ng, etc.). Since the efficiencies in different speed ranges are different, each speed range presents a piecewise function characteristic. For example, the Tt45-Wf functions in the two speed ranges of 80% - 85% Ng and 90% - 95% Ng are different.

[0062] The normal parameters include calculating the average value of all parameters 3 seconds before the engine anomaly, as shown in Table 2 below:

[0063] Table 2 below

[0064] Symbol Meaning Single-shot Symbol Two-shot Symbol Three-shot Symbol Average Gas Generator Speed in the First 3s <![CDATA[Ng -1正常 > <![CDATA[Ng -2正常 > <![CDATA[Ng -3正常 > Average Power Turbine Inlet Temperature in the First 3s <![CDATA[Tt45 -1正常 > <![CDATA[Tt45 -2正常 > <![CDATA[Tt45 -3正常 > Average Engine Fuel Supply in the First 3s <![CDATA[Wf -1正常 > <![CDATA[Wf -2正常 > <![CDATA[Wf -3正常 > Extreme Value of Engine Fuel Pressure in the First 3s <![CDATA[P -1正常极值 > <![CDATA[P -2正常极值 > <![CDATA[P -3正常极值 >

[0065] When it is determined that the fuel pressure and Tt45 of one engine are abnormal at the same time, the current parameters are recorded simultaneously. The current parameters include locking the abnormal fuel pressure state and recording all parameter values, as shown in Table 3 below:

[0066] Table 3 below

[0067] Symbol Meaning Single-shot Symbol Two-shot Symbol Three-shot Symbol Current Gas Generator Speed <![CDATA[Ng -1当前 > <![CDATA[Ng -2当前 > <![CDATA[Ng -3当前 > Current Power Turbine Inlet Temperature <![CDATA[Tt45 -1当前 > <![CDATA[Tt45 -2当前 > <![CDATA[Tt45 -3当前 > Current Engine Fuel Supply <![CDATA[Wf -1当前 > <![CDATA[Wf -2当前 > <![CDATA[Wf -3当前 > Extreme Value of Current Engine Fuel Pressure <![CDATA[P -1当前极值 > <![CDATA[P -2当前极值 > <![CDATA[P -3当前极值 >

[0068] The parameter reference is based on Ng-1正常 , Ng -2正常 , Ng -3正常 , perform linear interpolation on the baseline performance entered in the first step to obtain the corresponding Tt45 基准 , Wf 基准 , P 基准 , for example: if Ng -1 is normally 92%, then perform linear interpolation between 90% Ng and 95% Ng according to the relationships such as Ng - Wf, Ng - Tt45, Ng - P, etc., and calculate the fuel quantity A required for each 1°C increase in the first engine according to the functional relationship between Tt45 - Wf within this speed range. The interpolated parameters are shown in Table 4 below:

[0069] Table 4

[0070]

[0071] Step S20, obtain the corresponding pressure parameters from the normal parameters and the current parameters to calculate the extreme value of the fuel pressure of the first engine, as well as the extreme values of the fuel pressures of the second and third engines. The extreme value of the fuel pressure of the first engine satisfies the first condition, and the extreme values of the fuel pressures of the second and third engines respectively satisfy the second condition, initially confirming that there is a risk of fuel leakage in the first engine. It should be noted that under normal circumstances, the fuel systems of different engines on the UAV are independent of each other, and the fuel pressure P fluctuates stably within a certain range. Even if the first engine leaks fuel, it will not affect the working stability of the other two engines. Therefore, when the first engine (the first engine) leaks fuel, the current extreme value of the fuel pressure P -1 After the current extreme value exceeds the normal extreme value by a certain range (the normal value is the maximum value P of the current fuel pressure in the previous 3s -1 normal extreme value), then it is suspected that the first engine leaks fuel, and at the same time, the fuel flow measurement system is considered unreliable.

[0072] Due to the different installation positions of the three engines, there are their unique particularities, and in order to avoid the interference of factors such as aircraft attitude changes, flight environment, and the matching of the three engines (three engines) on the fuel pressure of the engine and affecting the judgment accuracy of this logic, it cannot be determined that there may be a leak just because the fuel of the first engine is abnormal. Only when the current extreme values of the fuel pressures of all three engines simultaneously satisfy the corresponding first condition and the second condition, the control system initially suspects that the fuel system of one engine leaks and executes the subsequent steps. Otherwise, it is considered that the engine fuel system is normal and continues to execute the judgment of this logic.

[0073] Step S30: Obtain the corresponding temperature parameters from the normal parameters and the current parameters to calculate the inlet temperature of each power turbine. The inlet temperature of the first power turbine satisfies the third condition, or its slope remains positive or negative for a duration greater than 2 s, and the inlet temperatures of the other two power turbines respectively satisfy the fourth condition, further confirming that there is a risk of fuel leakage in the first engine. It should be noted that even if the oil pressure fluctuates, it cannot be directly determined that there is fuel leakage. The abnormal change of Tt45 (inlet temperature of the power turbine) is another prominent feature of fuel leakage. Fuel leakage will directly affect Tt45, but different leakage conditions result in different change trends of Tt45: for example, a large amount of fuel leaking quickly will cause the overall state of the engine to decrease and Tt45 to drop rapidly; if a small amount of fuel leaks slowly, it will cause the oil pressure to be unstable, and the amount of fuel entering the engine body will fluctuate, resulting in frequent or intermittent fluctuations of Tt45, and the fluctuation range exceeds the normal level; if the fuel leaks into the flow channel (manifold flow channel), it will cause the Tt45 of this engine to rise slowly continuously. Under normal circumstances, the fluctuation range of Tt45 is ±6°C. When the inlet temperature of the first power turbine satisfies the third condition, or its slope remains positive or negative for a duration greater than 2 s, and the inlet temperatures of the other two power turbines respectively satisfy the fourth condition, it is determined that Tt45 is abnormal, and the next step is executed; otherwise, return to the first step. For the slope of the inlet temperature of the first power turbine to remain positive or negative for a duration greater than 2 s, under normal circumstances, when the load lever of the first engine remains unchanged, the parameter Tt45 of the engine fluctuates frequently within a small tolerance range, and the fluctuation phenomenon is that the slope of Tt45 is positive or negative alternately. However, when additional fuel leaks into the engine body and burns, it will cause Tt45 to rise continuously (2 s is an empirical value, and the duration will be different for different engines and can be adjusted according to the actual situation). At this time, the slope of Tt45 is positive (the slope is the change of Tt45 with time). When the set fuel leaks outside the engine, it will cause Tt45 to drop continuously (2 s is an empirical value, which can be appropriately modified for different engines). At this time, the slope of Tt45 is negative. The determination time of 2 s should not be too long because fuel leakage is an important fault, and long-term leakage may lead to harmful consequences such as the engine losing power / stopping / firing. Once a fault is determined, the next step should be executed as soon as possible, and stop / land / return as early as possible.

[0074] Step S40: Calculate the first fuel supply amount and the second fuel supply amount based on the corresponding parameters obtained from the normal parameters, current parameters, and parameter reference. The parameters obtained may include rotational speed, temperature, and fuel supply amount. When the first fuel supply amount and the second fuel supply amount respectively meet the fifth condition, it is confirmed that there is a fuel leak in the first engine. It should be noted that the corresponding parameters are obtained from the normal parameters, current parameters, and parameter reference, and these parameters include the fuel supply amount parameter and the turbine inlet temperature parameter. To ensure the balanced load of the engine, multi-engine aircraft will automatically trim to make each engine in a similar load state as much as possible. However, due to factors such as individual differences in engines and different degrees of performance attenuation, even in the trimmed state, there will be certain differences in the state parameters of each engine. However, no matter how they change, under normal circumstances, the relative fuel quantity among the three engines basically remains stable. If one engine leaks, the relative fuel quantity of the leaking engine compared to the other two engines will exceed the relative fuel quantity of the reference performance. Therefore, when the fuel flow simultaneously meets the fifth condition, it is finally determined that there is a fuel leak in one engine. Specifically, the first fuel supply amount and the second fuel supply amount are obtained by respectively extracting the corresponding parameters from the normal parameters, current parameters, and parameter reference. Specifically, the fuel supply amounts of the reference engines of each corresponding engine, the current fuel supply amount of the engine, the current power turbine inlet temperature, and the normal power turbine inlet temperature can be extracted, so that the first fuel supply amount and the second fuel supply amount can be calculated.

[0075] First, initially confirm the risk of oil leakage by the fuel pressure of each engine meeting the corresponding conditions, then further confirm the risk of oil leakage by the power turbine inlet temperature of each engine meeting the corresponding conditions, and finally confirm the fuel leakage of the engine by the fuel supply amount, realizing the accurate monitoring of the engine fuel leakage, improving the speed of detecting oil leakage, and enhancing safety. By comparing the parameters of multiple engines, detect the engine fuel leakage in advance and issue an alarm to avoid serious consequences such as fire caused by further fuel leakage, and improve the flight safety performance. This method is applicable to the installation environment.

[0076] Specifically, obtain the extreme value of the first engine fuel pressure by calculating the corresponding pressure parameters from the normal parameters and current parameters, including:

[0077] Obtain the first engine pressure difference based on the difference between the current extreme value of the first engine fuel pressure and the normal extreme value of the first engine fuel pressure.

[0078] The ratio of the first engine pressure difference to the normal extreme value of the first engine fuel pressure gives the extreme value of the first engine fuel pressure. It should be noted that the current extreme value of the first engine fuel pressure and the normal extreme value of the first engine fuel pressure can be obtained from the normal parameters and current parameters. The normal parameters and current parameters are obtained by automatically recording each parameter from the system. The extreme value of the first engine fuel pressure calculated is convenient for subsequent judgment of the oil leakage situation.

[0079] In one embodiment, obtaining the second and third engine fuel pressure extremes from the normal parameters and the current parameters includes:

[0080] Obtaining the second engine pressure difference based on the difference between the current second engine fuel pressure extreme and the normal second engine fuel pressure extreme;

[0081] Obtaining the second engine fuel pressure extreme from the ratio of the second engine pressure difference to the normal second engine fuel pressure extreme;

[0082] Obtaining the third engine pressure difference based on the difference between the current third engine fuel pressure extreme and the normal third engine fuel pressure extreme;

[0083] Obtaining the third engine fuel pressure extreme from the ratio of the third engine pressure difference to the normal third engine fuel pressure extreme. It should be noted that the current second engine fuel pressure extreme, the normal second engine fuel pressure extreme, the current third engine fuel pressure extreme, and the normal third engine fuel pressure extreme can be obtained from the normal parameters and the current parameters. The normal parameters and the current parameters are obtained by automatically recording each parameter from the system. The second engine fuel pressure extreme and the third engine fuel pressure extreme obtained by calculation facilitate subsequent judgment of the fuel leakage situation.

[0084] In one embodiment, the first engine fuel pressure extreme satisfies the first condition, including:

[0085]

[0086] where P -1当前极值 represents the current first engine fuel pressure extreme, and P -1正常极值 represents the normal first engine fuel pressure extreme.

[0087] Specifically, the second and third engine fuel pressure extremes respectively satisfy the second condition, including:

[0088]

[0089] P -2当前极值 represents the current second engine fuel pressure extreme, P -2正常极值 represents the normal second engine fuel pressure extreme, P -3当前极值 represents the current third engine fuel pressure extreme, and P -3正常极值 represents the normal third engine fuel pressure extreme. Only by simultaneously satisfying the conditions corresponding to the fuel limit pressure values of the above three engines can the risk of fuel leakage be initially confirmed. Otherwise, it is considered that the engine fuel system is normal, and the above steps are continued.

[0090] In one embodiment, obtaining the inlet temperature of the power turbine for each engine by obtaining the corresponding temperature parameters from the normal parameters and the current parameters includes:

[0091] The inlet temperature of each engine turbine is obtained based on the difference between the current inlet temperature of each engine turbine and the average value of the normal inlet temperatures of each engine turbine. Here, the average value of the normal inlet temperatures of each engine turbine is the average value of the normal inlet temperatures of each engine turbine in the previous 3 seconds compared to the current ones. It should be noted that the inlet temperature of each engine turbine and the average value of the normal inlet temperatures of each engine turbine respectively include the current inlet temperature of the first engine turbine, the average value of the normal inlet temperatures of the first engine turbine, the inlet temperature of the second engine turbine, the average value of the normal inlet temperatures of the second engine turbine, the inlet temperature of the third engine turbine, and the average value of the normal inlet temperatures of the third engine turbine. The average value of the normal inlet temperatures of the first engine turbine, the average value of the normal inlet temperatures of the second engine turbine, and the average value of the normal inlet temperatures of the third engine turbine are all average values calculated from the normal values in the previous (abnormal) three seconds.

[0092] Specifically, the inlet temperature of the first engine turbine satisfying the third condition includes:

[0093] |Tt45 -1当前 -Tt45 -1平均 |≥8℃

[0094] Wherein, Tt45 -1当前 represents the current inlet temperature of the first engine turbine, and Tt45 -1平均 represents the average value of the normal inlet temperatures of the first engine turbine.

[0095] Furthermore, the inlet temperatures of the other two engine turbines respectively satisfy the fourth condition, including:

[0096] |Tt45 -2当前 -Tt45 -2平均 |<6℃

[0097] |Tt45 -3当前 -Tt45 -3平均 |<6℃

[0098] Wherein, Tt45 -2当前 represents the current inlet temperature of the first engine turbine, Tt45 -2平均 represents the average value of the normal inlet temperatures of the first engine turbine, Tt45 -3当前 represents the current inlet temperature of the first engine turbine, and Tt45 -3平均 represents the average value of the normal inlet temperatures of the first engine turbine.

[0099] Only by calculating the inlet temperatures of the above-mentioned engine turbines respectively satisfying the corresponding conditions, and adding that the three fuel limit pressure values satisfy the corresponding conditions, can it be further determined that there is a risk of oil leakage and continue to confirm the oil leakage. Otherwise, the first step is re-executed.

[0100] In one embodiment, calculating the first fuel supply amount and the second fuel supply amount according to the corresponding parameters obtained from the normal parameters, the current parameters, and the parameter reference includes:

[0101] Calculating the fuel amount A required for each 1°C increase of the first engine according to the relationship between the power turbine inlet temperature and the engine fuel supply amount. Specifically, obtaining the corresponding parameters of Tt45 and Wf from Table 2 and Table 4 above, so as to obtain the relationship of Tt45 - Wf, and calculating the fuel amount A required for each 1°C increase of the first engine according to this relationship. In order to finally determine whether there is fuel leakage in the first engine, it is also necessary to confirm whether the increase in the fuel flow rate of the first engine is larger than that of the second and third engines. However, since the measurement of the fuel flow rate of the first engine is not reliable, therefore, this method reconstructs the fuel flow rate of the first engine through the reference performance, and finally determines whether the first engine leaks after comparing the fuel flow rates of the three engines. Specifically, for the relationship of Tt45 - Wf, it is described as follows based on this example: The performances at 90% ng (gas generator speed) and 95% ng speed are respectively recorded, that is, Tt45, Wf (fuel supply amount), and P (extreme fuel pressure) at 90% ng speed. Respectively represented by Tt45 90 , Wf 90 , P 90 and Tt45 95 , Wf 95 , P 95 , it is possible to obtain the linear equation Tt45 = f(ng) based on the two known points of (90% ng, Tt45 90 ) and (95% ng, Tt45 95 ). Substituting 92% ng, the Tt45 92 at 92% ng speed can be obtained. By analogy, the linear equations Wf = f(ng) and P = f(ng) can be obtained, and then Wf 92 , P 92 . Thus, calculating the power turbine inlet temperature, the engine fuel supply amount, and the extreme engine fuel pressure is realized, and finally the fuel amount A required for each 1°C increase of the first engine is obtained.

[0102] According to the calculated fuel amount A required for each 1°C increase of the first engine, the fuel flow rate of the first engine can be inversely calculated based on the abnormal temperature rise to obtain the abnormally entered fuel flow rate, and then reconstructed by adding the fuel flow rate Wf -1正常 under normal conditions.

[0103] Reconfirm the current fuel supply amount of the first engine, and the specific steps are as follows:

[0104] Wf -1当前 = Wf -1正常 + (Tt45 -1当前 - Tt45 -1正常)×A

[0105] Among them, Wf -1正常 is the normal fuel supply for the first engine, Tt45 -1当前 is the current turbine inlet temperature of the first engine, Tt45 -1正常 is the normal turbine inlet temperature of the first power turbine, and A is the fuel quantity;

[0106] Calculate the first fuel supply and the second fuel supply according to the reconfirmed current fuel supply of the first engine. The specific calculation steps are as follows:

[0107]

[0108]

[0109] Wf1 当前变化 -Wf1 基准变化 = the first fuel supply

[0110]

[0111] Wf2 当前变化 -Wf2 基准变化 = the first fuel supply

[0112] Among them, Wf1 当前变化 is the current fuel supply change between the first engine and the second engine, Wf1 基准变化 is the reference fuel supply change between the first engine and the second engine, Wf -1当前 is the current fuel supply of the first engine, Wf -2当前 is the current fuel supply of the second engine, Wf -3当前 is the current fuel supply of the third engine, Wf -1基准 is the reference fuel supply of the first engine, Wf -2基准 is the reference fuel supply of the second engine, Wf -3基准 is the reference fuel supply of the third engine.

[0113] It should be noted that the above parameters can all be obtained from the corresponding normal parameters and the current parameter reference. Calculate the first fuel supply and the second fuel supply through the above parameters, and then the fuel leakage situation can be judged according to the first fuel supply and the second fuel supply. In addition, the engine fuel leakage will directly cause large fluctuations in the fuel pressure P and Tt45, and the fluctuation range exceeds the normal level. Due to the fuel fluctuation, the fuel flow measurement of this engine is inaccurate or unreliable, and it cannot directly judge whether this engine leaks according to the fuel flow. Therefore, this method is based on the fluctuation characteristics of the fuel pressure P and Tt45 and the reference performance of 3 engines, judges the change trend of Tt45, reconstructs the fuel flow of this engine, and finally determines whether the fuel leaks through multi-engine comparison.

[0114] In one embodiment, the first fuel supply amount and the second fuel supply amount respectively satisfy a fifth condition, including:

[0115]

[0116] Wf -1当前 is the current fuel supply amount of the first engine, Wf -2当前 is the current fuel supply amount of the second engine, Wf -3当前 is the current fuel supply amount of the third engine, Wf -1基准 is the reference fuel supply amount of the first engine, Wf -2基准 is the reference fuel supply amount of the second engine, Wf -3基准 is the reference fuel supply amount of the third engine. By making the fuel supply amount satisfy the corresponding conditions, the determination of oil leakage is finally achieved. And in combination with the fact that the fuel pressures of each engine in the above steps satisfy the corresponding conditions to preliminarily confirm the existence of an oil leakage risk, and the inlet temperatures of the power turbines of each engine satisfy the corresponding conditions to further confirm the existence of an oil leakage risk, the accurate monitoring of engine fuel leakage is realized, the speed of detecting oil leakage is increased, and the safety is improved.

[0117] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting engine fuel leakage based on multiple drones, characterized in that, The method includes: Obtaining the normal parameters, current parameters, and parameter benchmarks corresponding to at least three engines; Obtaining the corresponding pressure parameters from the normal parameters and the current parameters to calculate the extreme value of the fuel pressure of the first engine, as well as the extreme values of the fuel pressures of the second and third engines. The extreme value of the fuel pressure of the first engine meets the first condition, and the extreme values of the fuel pressures of the second and third engines respectively meet the second condition, preliminarily confirming that there is a risk of fuel leakage in the first engine; Obtaining the corresponding temperature parameters from the normal parameters and the current parameters to calculate the inlet temperature of the power turbine for each engine. The inlet temperature of the power turbine of the first engine meets the third condition, and the inlet temperatures of the power turbines of the other two engines respectively meet the fourth condition, further confirming that there is a risk of fuel leakage in the first engine; Obtaining the corresponding parameters from the normal parameters, the current parameters, and the parameter benchmarks to calculate the first fuel supply amount and the second fuel supply amount. When the first fuel supply amount and the second fuel supply amount respectively meet the fifth condition, it is confirmed that there is fuel leakage in the first engine.

2. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, wherein Obtaining the corresponding pressure parameters from the normal parameters and the current parameters to calculate the extreme value of the fuel pressure of the first engine, including: Obtaining the pressure difference of the first engine according to the difference between the current extreme value of the fuel pressure of the first engine and the normal extreme value of the fuel pressure of the first engine; Obtaining the extreme value of the fuel pressure of the first engine by the ratio of the pressure difference of the first engine to the normal extreme value of the fuel pressure of the first engine.

3. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, characterized in that Obtaining the extreme values of the fuel pressures of the second and third engines by obtaining the corresponding pressure parameters from the normal parameters and the current parameters, including: Obtaining the pressure difference of the second engine according to the difference between the current extreme value of the fuel pressure of the second engine and the normal extreme value of the fuel pressure of the second engine; Obtaining the extreme value of the fuel pressure of the second engine by the ratio of the pressure difference of the second engine to the normal extreme value of the fuel pressure of the second engine; Obtaining the pressure difference of the third engine according to the difference between the current extreme value of the fuel pressure of the third engine and the normal extreme value of the fuel pressure of the third engine; Obtaining the extreme value of the fuel pressure of the third engine by the ratio of the pressure difference of the third engine to the normal extreme value of the fuel pressure of the third engine.

4. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, wherein The extreme value of the fuel pressure of the first engine meets the first condition, including: Among them, P -1当前极值 represents the current extreme value of the fuel pressure of the first engine, and P -1正常极值 represents the extreme value of the normal fuel pressure of the first engine.

5. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, wherein The extreme values of the fuel pressures of the second and third engines respectively meet the second condition, including: P -2当前极值 represents the current extreme value of the fuel pressure of the second engine, P -2正常极值 represents the normal extreme value of the fuel pressure of the second engine, P -3当前极值 represents the current extreme value of the fuel pressure of the third engine, P -3正常极值 represents the normal extreme value of the fuel pressure of the third engine.

6. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, wherein, Obtaining the inlet temperature of the power turbine for each engine by obtaining the corresponding temperature parameters from the normal parameters and the current parameters, including: Obtaining the inlet temperature of the power turbine for each engine according to the difference between the current inlet temperature of the power turbine for each engine and the average value of the normal inlet temperatures of the power turbines for each engine, where the average value of the normal inlet temperatures of the power turbines for each engine is the average value of the normal inlet temperatures of the power turbines for each engine in the previous 3 s compared to the current inlet temperature of the power turbine for each engine.

7. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, characterized in that The inlet temperature of the power turbine of the first engine meets the third condition, including: |Tt45 -1当前 -Tt45 -1平均 |≥8 °C Among them, Tt45 -1当前 represents the current inlet temperature of the first power turbine, Tt45 -1平均 represents the average value of the normal inlet temperature of the first power turbine.

8. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, wherein The inlet temperatures of the power turbines of the other two engines respectively meet the fourth condition, including: |Tt45 -2当前 -Tt45 -2平均 |<6℃ |Tt45 -3当前 -Tt45 -3平均 |<6℃ Among them, Tt45 -2当前 represents the current inlet temperature of the first power turbine, Tt45 -2平均 represents the average value of the normal inlet temperature of the first power turbine, Tt45 -3当前 represents the current inlet temperature of the first power turbine, Tt45 -3平均 represents the average value of the normal inlet temperature of the first power turbine.

9. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 1, wherein Obtaining the first fuel supply amount and the second fuel supply amount by obtaining the corresponding parameters from the normal parameters, the current parameters, and the parameter benchmarks, including: Calculating the fuel amount A required for the first engine to increase by 1 °C according to the relationship between the inlet temperature of the power turbine and the fuel supply amount of the engine; Reconfirming the current fuel supply amount of the first engine, and the specific steps are as follows: Wf -1当前 = Wf -1正常 + (Tt45 -1当前 - Tt45 -1正常 ) × A Among them, Wf -1正常 is the normal fuel supply for the first engine, Tt45 -1当前 is the current turbine inlet temperature of the first engine, Tt45 -1正常 is the normal power turbine inlet temperature of the first engine, and A is the fuel quantity; Calculate the first fuel supply amount and the second fuel supply amount according to the reconfirmed current fuel supply amount of the first shot. The specific calculation steps are as follows: Wf1 当前变化 -Wf1 基准变化 = First fuel supply amount Wf2 当前变化 -Wf2 基准变化 = First fuel supply amount Among them, Wf1 当前变化 is the current fuel supply change amount between the first and the second engines, and Wf1 基准变化 is the reference fuel supply change amount between the first and the second engines, and Wf -1当前 is the current fuel supply amount of the first engine, and Wf -2当前 is the current fuel supply amount of the second engine, and Wf -3当前 is the current fuel supply amount of the third engine, and Wf -1基准 is the reference fuel supply amount of the first engine, and Wf -2基准 is the reference fuel supply amount of the second engine, and Wf -3基准 is the reference fuel supply amount of the third engine.

10. The method for detecting engine fuel leakage based on multiple engines of an unmanned aerial vehicle according to claim 9, characterized in that, The first fuel supply amount and the second fuel supply amount respectively meet the fifth condition, including: Wf -1当前 is the current fuel supply of the first engine, Wf -2当前 is the current fuel supply of the second engine, Wf -3当前 is the current fuel supply of the third engine, Wf -1基准 is the reference fuel supply of the first engine, Wf -2基准 is the reference fuel supply of the second engine, Wf -3基准 is the reference fuel supply of the third engine.

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