An aero-engine automatic re-ignition method based on characteristic parameter change

Abstract

The application belongs to the field of aero-engine control, and particularly relates to an aero-engine automatic re-ignition method based on characteristic parameter change. The method comprises the following steps: step one, obtaining an entering-out condition, and entering step two when the entering-out condition is met; step two, obtaining an engine-out condition, identifying engine-out according to the engine-out condition, and entering step three when engine-out is identified; step three, igniting through an engine igniter, and supplying oil according to a preset engine oil supply rule, and entering step four when the engine igniter is turned off after continuous ignition of the engine igniter for T C seconds; and step four, obtaining a re-ignition success condition, judging whether re-ignition is successful according to the re-ignition success condition, and ending if yes. The application can quickly identify the engine-out state of an engine and automatically re-ignite, and avoids signal misjudgment caused by single signal interference or disturbance, or failure to judge engine-out caused by single signal failure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engine control, and particularly relates to an aero-engine automatic re-ignition method based on characteristic parameter change. BACKGROUND

[0002] During the working process of an aero-engine, if fuel supply interruption, pilot error operation, and inlet distortion or severe weather conditions occur, the engine combustion chamber may be extinguished, resulting in unstable engine operation. If ignition is not restored in time, the engine may be shut down in the air, causing the engine to lose thrust, which is very serious for single-engine aircraft and may result in aircraft damage and loss of life. For multi-engine aircraft, it also affects flight safety and causes additional operating burden on the pilot. Therefore, the aircraft has more stringent requirements for in-flight extinction of the engine, requiring quick judgment and re-ignition when the engine is extinguished to ensure that the engine can stably and reliably provide the required thrust for the aircraft.

[0003] Common engine restart methods after extinction include windmill starting and inertia starting. Windmill starting is a method in which the engine is completely stopped, and the engine rotor is rotated by ram pressure generated by the aircraft in flight. Within a certain starting envelope, windmill starting is achieved by pilot instructions. Inertia starting is a method in which the engine is extinguished, the speed is reduced to the inertia starting speed, and the engine is automatically ignited by the engine control system to restart the engine. The main disadvantages of the current technical solution are as follows: Windmill starting is a method in which the engine is stopped after the combustion chamber is extinguished and enters the windmill state. However, in the windmill state, the air flow rate into the combustion chamber is high, and the pressure and temperature are low, making it difficult to ignite and stabilize combustion. Therefore, windmill starting cannot be successful under any flight conditions and requires certain height and speed conditions. The higher the flight altitude, the lower the pressure and temperature of the air entering the combustion chamber, making it difficult to ignite the combustion chamber. If the flight speed is too high, the air flow rate into the combustion chamber is too large, making it difficult to ignite the fuel-air mixture and stabilize the flame. If the flight speed is too low, the windmill speed may be too low, and if the fuel supply is too low, the turbine output power may be insufficient, causing the starting to be suspended. If the fuel supply is too high, the temperature before the turbine may be too high. Inertia starting is an automatic starting program executed by the engine control system after the engine is accidentally stopped in the air. Although it is an automatic starting method, the logic is triggered only when the core engine speed is reduced to the target speed, which is generally lower than the idle speed. Therefore, if the engine is running at a high state, the engine thrust will change greatly, resulting in a long period of thrust loss.

[0004] Therefore, it is desirable to have a technical solution to overcome or at least alleviate at least one of the aforementioned deficiencies of the prior art. SUMMARY

[0005] The purpose of the present application is to provide an aero-engine automatic re-ignition method based on characteristic parameter change to solve at least one problem existing in the prior art.

[0006] The technical solution of the present application is:

[0007] An aero-engine automatic re-ignition method based on characteristic parameter change, comprising:

[0008] Step one, obtaining an entering-out condition, when the entering-out condition is met, entering step two;

[0009] Step two, obtaining an engine-out condition, identifying engine-out according to the engine-out condition, when engine-out is identified, entering step three;

[0010] Step three, igniting by an engine igniter and supplying oil according to a preset engine oil supply rule, when the engine igniter is continuously ignited for T C s and the engine igniter is turned off, entering step four;

[0011] Step four, obtaining a re-ignition success condition, judging whether re-ignition is successful according to the re-ignition success condition, if yes, ending.

[0012] In at least one embodiment of the present application, the entering-out condition is:

[0013] X D -X F >Δ

[0014] Wherein, X F is a feedback value of a closed-loop control loop or a limiting loop, X D is a first threshold value, and Δ is a deviation.

[0015] In at least one embodiment of the present application, in step two, the obtaining of the engine-out condition and the identification of engine-out according to the engine-out condition comprise:

[0016] The engine characteristic parameter change rate is calculated as:

[0017]

[0018] Wherein, k represents a current period, the k period is defined as the period when the out condition is entered, k-1 represents a previous period, T represents a collection period, and Y represents an engine characteristic parameter measurement value;

[0019] Then, the engine characteristic parameter change rates of the last five periods are respectively:

[0020]

[0021] wherein the engine characteristic parameters include high-pressure rotor speed N2, low-pressure rotor speed N1, turbine after-exhaust temperature T5;

[0022] The high-pressure rotor speed N2 change rates of the continuous 5 cycles are respectively:

[0023]

[0024] The low-pressure rotor speed N1 change rates of the continuous 5 cycles are respectively:

[0025]

[0026] The turbine after-exhaust temperature T5 change rates of the continuous 5 cycles are respectively:

[0027]

[0028] When any 4 of the high-pressure rotor speed N2 change rates of the continuous 5 cycles are greater than the second threshold value ΔY N2 , it is considered that the first engine flameout condition is met;

[0029] When any 4 of the low-pressure rotor speed N1 change rates of the continuous 5 cycles are greater than the third threshold value ΔY N1 , it is considered that the second engine flameout condition is met;

[0030] When any 4 of the turbine after-exhaust temperature T5 change rates of the continuous 5 cycles are greater than the fourth threshold value ΔY T5 , it is considered that the third engine flameout condition is met;

[0031] When at least 2 of the first engine flameout condition, the second engine flameout condition, and the third engine flameout condition are met, it is considered that the engine is flamed out.

[0032] In at least one embodiment of the present application, in step four, the re-ignition success condition is obtained, and whether the re-ignition is successful is judged according to the re-ignition success condition, which includes:

[0033] The turbine after-exhaust temperature T5 rise rates of the continuous 5 cycles after entering the flameout judgment are respectively:

[0034]

[0035] wherein l represents a cycle after k cycles;

[0036] When the turbine after-exhaust temperature T5 rise rates of the continuous 5 cycles after entering the flameout judgment are all greater than the fifth threshold value ΔZ T5 , it is considered that the engine re-ignition is successful.

[0037] In at least one embodiment of the present application, the method further comprises step five: when it is determined that the re-ignition is unsuccessful according to the re-ignition success condition, entering engine inertia start or airborne start.

[0038] In at least one embodiment of the present application, the method further comprises step five: when it is determined that the re-ignition is unsuccessful according to the re-ignition success condition, entering engine inertia start, and when the engine inertia start is unsuccessful, entering airborne start.

[0039] The present application has at least the following beneficial technical effects:

[0040] The automatic re-ignition method for an aero-engine based on characteristic parameter change of the present application can quickly identify the engine flameout state and automatically re-ignite, without requiring additional operations by the pilot. Meanwhile, the use of multiple characteristic parameter changes for judgment can avoid signal misjudgment caused by single signal interference or disturbance, or the inability to determine flameout caused by single signal failure. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a flow chart of the automatic re-ignition method for an aero-engine based on characteristic parameter change according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] To make the purposes, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings. In the drawings, the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some of the embodiments of the present application, rather than all the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0043] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship shown in the drawings, and are only intended to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0044] The embodiments of the present application will be described below with reference to the drawings. Figure 1The application is further described in detail.

[0045] The application provides an aero-engine automatic re-ignition method based on characteristic parameter change, comprising the following steps:

[0046] Step one, obtaining an entering-out condition, when the entering-out condition is met, entering step two;

[0047] Step two, obtaining an engine-out condition, identifying engine-out according to the engine-out condition, when the engine-out is identified, entering step three;

[0048] Step three, igniting through an engine igniter and supplying oil according to a preset engine oil supply rule, when the engine igniter is closed after continuously igniting for T C s, entering step four;

[0049] Step four, obtaining a re-ignition success condition, judging whether the re-ignition is successful according to the re-ignition success condition, if yes, ending.

[0050] The aero-engine automatic re-ignition method based on characteristic parameter change of the application is relatively easy to start again when the engine is hot and has not been completely cooled after being just out, so the earlier the engine-out is judged and the ignition is performed in time, the higher the success rate of starting again is when the engine is still hot. When the engine is stably working, the parameters such as rotation speed and exhaust temperature remain relatively stable, when the engine appears abnormal engine-out phenomenon, the engine rotation speed drops and the exhaust temperature decreases, by monitoring the change trend of the above parameters, whether the engine is abnormally out can be judged. At this time, if the engine-out state is judged through the engine related working parameters, the measures such as increasing oil supply and continuously igniting can be taken to make the engine return to normal working state in time, improving the safety and reliability of the control system.

[0051] The aero-engine automatic re-ignition method based on characteristic parameter change of the application comprises four main steps of entering-out condition judgment, engine-out condition judgment based on parameter change, automatic re-ignition logic execution and re-ignition success condition judgment, in addition, other re-starting logic execution steps are adopted when the automatic re-ignition is not successful, such as shown in the figure. Figure 1

[0052] Firstly, S001, entering-out condition judgment

[0053] ​When the engine is normally in steady state, the parameters such as speed, temperature and pressure also remain in a relatively stable state, and the feedback signal measured by the sensor is close to the given value calculated by the engine control system. Therefore, when the engine is in normal operation, if the feedback value of the closed-loop control loop or the limiting loop is less than the given value, and the deviation is greater than the preset value, it indicates that the engine may be off. In this embodiment, the entering off condition is:

[0054] X D -X F >Δ

[0055] Wherein, X F is the feedback value of the closed-loop control loop or the limiting loop, X D is the first threshold value, and Δ is the deviation (the value of Δ should be selected in combination with engineering practice).

[0056] S002, off condition judgment based on parameter change

[0057] When the engine is in stable operation, the characteristic parameters such as the speed and temperature of the engine remain relatively stable, and when the engine is off, the speed and temperature of the engine will quickly drop, so by identifying the speed and temperature drop rate, it can be judged whether the engine is off abnormally. In order to avoid signal misjudgment caused by single signal interference or disturbance, or unable to judge off due to single signal failure, in this embodiment, the changes of three characteristic parameters of the high-pressure rotor speed N2, the low-pressure rotor speed N1 and the turbine exhaust temperature T5 of the engine are used to identify the engine off.

[0058] Specifically, the engine off condition is obtained, and the engine off identification is performed according to the engine off condition, which includes:

[0059] The engine characteristic parameter change rate is calculated as:

[0060]

[0061] Wherein, k represents the current period, the k period is defined as the period when the off judgment is entered, k-1 represents the previous period, and the same applies to the subsequent periods, T represents the collection period, and Y represents the engine characteristic parameter measurement value.

[0062] Then, the engine characteristic parameter change rates of the continuous 5 periods are respectively:

[0063]

[0064] Wherein, the engine characteristic parameters include the high-pressure rotor speed N2, the low-pressure rotor speed N1 and the turbine exhaust temperature T5.

[0065] Then, the high-pressure rotor speed N2 change rates of the continuous 5 periods are respectively:

[0066]

[0067] The change rates of the low-pressure rotor speed N1 of the continuous 5 cycles are respectively:

[0068]

[0069] The change rates of the turbine exhaust temperature T5 of the continuous 5 cycles are respectively:

[0070]

[0071] When any 4 of the change rates of the high-pressure rotor speed N2 of the continuous 5 cycles are greater than the second threshold value ΔY N2 , it is considered that the first engine stall condition is met;

[0072] When any 4 of the change rates of the low-pressure rotor speed N1 of the continuous 5 cycles are greater than the third threshold value ΔY N1 , it is considered that the second engine stall condition is met;

[0073] When any 4 of the change rates of the turbine exhaust temperature T5 of the continuous 5 cycles are greater than the fourth threshold value ΔY T5 , it is considered that the third engine stall condition is met;

[0074] When at least 2 of the first engine stall condition, the second engine stall condition and the third engine stall condition are met, it is considered that the engine is stalled.

[0075] Wherein, the specific values of the second threshold value ΔY N2 , the third threshold value ΔY N1 and the fourth threshold value ΔY T5 are determined according to engineering practice.

[0076] S003, executing automatic re-ignition logic

[0077] When it is judged that the engine is stalled, the engine is ignited and fuel is supplied, the engine igniter is continuously ignited for T C s, and fuel is supplied according to the given fuel supply rule of the engine.

[0078] The continuous ignition time is determined according to engineering practice, and the engine igniter is turned off after the engine igniter is continuously ignited for T C s.

[0079] Further, S004, re-ignition success condition judgment

[0080] When the engine is successfully ignited, the exhaust temperature of the engine will rapidly rise, and by identifying the rise in exhaust temperature, it can be determined whether the re-ignition is successful. In the preferred embodiment of the present application, after entering the flameout judgment logic, when the turbine rear exhaust temperature T5 rise rate of the consecutive 5 cycles is greater than the preset fifth threshold value ΔZ T5 , the engine is considered to have successfully re-ignited, and the re-ignition judgment logic is exited. The turbine rear exhaust temperature T5 rise rate of the consecutive 5 cycles after entering the flameout judgment is:

[0081]

[0082] Wherein, I represents the period after k period.

[0083] S005, other restart logic execution

[0084] When the re-ignition success condition is determined to be unsuccessful, the engine inertia start or in-flight start is entered. When the re-ignition success condition is determined to be unsuccessful, the engine inertia start can also be entered, and when the engine inertia start is unsuccessful, the in-flight start is entered.

[0085] In this embodiment, if the engine high pressure physical speed drops to the inertia start speed and the re-ignition success logic has not been triggered, the engine inertia start logic is entered, and the re-ignition logic is exited if the start is successful; if the inertia start is not successful, the pilot operates the in-flight start logic, and after the in-flight start logic is executed, the re-ignition judgment logic is exited regardless of whether the restart is successful. This part of the content is prior art, and there is relevant engineering practice, and the specific control logic will not be described again.

[0086] The automatic re-ignition method for an aero-engine based on characteristic parameter changes of the present application can quickly identify the engine flameout state and automatically re-ignite by identifying the change characteristics of the engine characteristic parameters, without the need for additional pilot operations. On the other hand, multiple characteristic parameter changes are used for judgment, avoiding signal misjudgment due to single signal interference or disturbance, or being unable to judge the flameout due to a single signal fault.

[0087] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An automatic re-ignition method for an aeroengine based on a characteristic parameter variation, characterized in that, The method comprises the following steps: Step 1: obtaining an entering-off condition, and entering step 2 when the entering-off condition is met; Step 2: obtaining an engine-off condition, identifying engine-off according to the engine-off condition, and entering step 3 when engine-off is identified; Step three, ignite by engine igniter, and fuel according to preset engine fueling law, when engine igniter continues to ignite T C seconds, turn off engine igniter, enter step four; Step 4: obtaining a re-ignition success condition, judging whether re-ignition is successful according to the re-ignition success condition, and ending if yes; The entering-off condition is: X D -X F >△ Wherein, X F is the feedback value of the closed-loop control loop or the limiting loop, X D is the first threshold value, and △ is the deviation. In step 2, the engine-off condition is obtained, and engine-off is identified according to the engine-off condition, which comprises the following steps: The engine characteristic parameter change rate is calculated as follows: Wherein, k represents the current period, k period is defined as the period when the off condition is entered, k-1 represents the previous period, T represents the collection period, and Y represents the engine characteristic parameter measurement value; Then, the engine characteristic parameter change rates of the last five periods are respectively as follows: Wherein, the engine characteristic parameters comprise high-pressure rotor speed N2, low-pressure rotor speed N1 and turbine exhaust temperature T5; The high-pressure rotor speed N2 change rates of the last five periods are obtained respectively as follows: The low-pressure rotor speed N1 change rates of the last five periods are obtained respectively as follows: The turbine exhaust temperature T5 change rates of the last five periods are obtained respectively as follows: When any 4 of the change rates of the high-pressure rotor rotational speed N2 for 5 consecutive periods are greater than the second threshold value ΔY N2 , it is considered that the first engine stall condition is satisfied. When any 4 of the low-pressure rotor speed N1 change rates of 5 consecutive cycles are greater than the third threshold value ΔY N1 , it is considered that the second engine stall condition is satisfied. When any 4 of the change rates of the turbine exhaust gas temperature T5 for 5 consecutive periods are greater than the fourth threshold value ΔY T5 , it is considered that the third engine stall condition is satisfied. When at least two of the first engine-off condition, the second engine-off condition and the third engine-off condition are met, the engine is considered to be off; Step 5: when it is judged that re-ignition is unsuccessful according to the re-ignition success condition, entering engine inertia starting or air starting.

2. The method of claim 1, wherein, In step 4, the re-ignition success condition is obtained, and whether re-ignition is successful is judged according to the re-ignition success condition, which comprises the following steps: The turbine exhaust temperature T5 rise rates of the last five periods after entering the off condition are obtained respectively as follows: Wherein, l represents the period after k period; When the rise rate of the turbine exhaust gas temperature T5 in the successive 5 cycles after the entry into the misfire judgment is greater than the fifth threshold value ΔZ T5 , it is considered that the engine is successfully re-ignited.

3. The method of claim 2, wherein, Step 5: when it is judged that re-ignition is unsuccessful according to the re-ignition success condition, entering engine inertia starting, and entering air starting when engine inertia starting is unsuccessful.

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