Lubricating oil supply system and high temperature limit test method for lubricating oil

Abstract

This invention provides a lubricating oil supply system and a method for testing the high-temperature limitation of lubricating oil. The lubricating oil supply system is used for high-temperature limitation testing of lubricating oil. The system includes a supply assembly for conveying self-circulating lubricating oil stored in an oil tank, and a first heat exchange device for supplying the lubricating oil to the transmission system after cooling it. The inlet of the first heat exchange device is connected to the supply assembly; the outlet of the first heat exchange device is connected to the transmission system. The lubricating oil supply system also includes a first bypass pipeline, a first valve, and a second valve. The first bypass pipeline connects the supply assembly and the outlet of the first heat exchange device; the first valve is located on the first bypass pipeline; and the second valve is located on the supply pipeline connecting the supply assembly and the inlet of the first heat exchange device. The above-described lubricating oil supply system and high-temperature limitation testing method can achieve temperature regulation of the lubricating oil system and meet the airworthiness test conditions for high-temperature limitation of lubricating oil.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil system technology for aircraft engines, and in particular to a lubricating oil supply system and a method for testing the high temperature limitation of lubricating oil. Background Technology

[0002] The lubricating oil system is a crucial subsystem of an aero-engine. It must provide efficient cooling and lubrication, ensuring proper operation under all operating conditions within the declared engine operating envelope. Bearings and transmission systems generate significant heat during operation; the lubricating oil flowing through these systems prevents heat buildup and excessive damage. However, as a relatively closed, self-circulating system, the lubricating oil system can experience temperature increases during actual aero-engine operation. In cases of insufficient fuel cooling at idle or prolonged operation under high loads, the temperature in the lubricating oil flow path may rise continuously due to insufficient cooling, leading to decreased heat dissipation efficiency in the main bearings and transmission system, and ultimately causing overheating damage to related components.

[0003] According to the CCAR33.71 airworthiness regulations for aircraft engines under CCAR33, to ensure that the damage and lifespan of lubricating oil system components and accessories meet expectations, the lubricating oil system should be able to operate stably for extended periods under limited high-temperature oil environments without incurring damage exceeding the limits. Verification of the lubricating oil's high-temperature limits is conducted during the CCAR33.87 engine 150-hour endurance test, ensuring that the disassembly inspection of lubricating oil system components and accessories after the test does not reveal excessive damage or performance degradation.

[0004] However, the steady-state long-term rated operating conditions in the endurance test require the lubricating oil temperature to be kept at the limit high temperature. Since the engine's lubricating oil system supply circuit is equipped with accessories such as fuel lubricating oil cooler, air lubricating oil heat exchanger, and servo fuel heater for lubricating oil cooling, and the heat dissipation is affected by many factors such as fuel flow, ambient temperature, and lubricating oil temperature, the lubricating oil system cannot be stably maintained at the lubricating oil high temperature limit conditions that need to be verified. Summary of the Invention

[0005] The purpose of this invention is to provide a lubricating oil supply system and a lubricating oil high-temperature limitation test method, which can realize the temperature regulation of the lubricating oil system and meet the airworthiness test conditions requirements for lubricating oil high-temperature limitation.

[0006] One aspect of the present invention provides a lubricating oil supply system for use in high-temperature limit tests of lubricating oil. The lubricating oil supply system includes a supply assembly for conveying self-circulating lubricating oil stored in an oil tank, and a first heat exchange device for supplying the lubricating oil to a transmission system after cooling it. The inlet of the first heat exchange device is connected to the supply assembly; the outlet of the first heat exchange device is connected to the transmission system. The lubricating oil supply system further includes a first bypass pipeline, a first valve, and a second valve. The first bypass pipeline connects the supply assembly and the outlet of the first heat exchange device. The first valve is disposed in the first bypass pipeline; the second valve is disposed in the supply pipeline connecting the supply assembly and the inlet of the first heat exchange device. The first valve and the second valve are respectively used to control the flow rate of the lubricating oil flowing through the first bypass pipeline and the first heat exchange device to adjust the temperature of the lubricating oil, thereby enabling the lubricating oil temperature to reach the target high-temperature limit value required for the high-temperature limit test.

[0007] In one embodiment, the lubricating oil supply system further includes a second heat exchange device; the second heat exchange device is connected to the outlet of the first heat exchange device and the transmission system; the lubricating oil supply system further includes a second bypass pipeline and a third valve; the second bypass pipeline is connected to the inlet and outlet of the heat exchange medium that exchanges heat with the lubricating oil in the second heat exchange device; the third valve is disposed on the second bypass pipeline.

[0008] In one embodiment, the second heat exchange device is a lubricating oil radiator; the lubricating oil radiator includes a lubricating oil inlet, a lubricating oil outlet, a fuel inlet, and a fuel outlet, the lubricating oil inlet and the lubricating oil outlet are connected, the fuel inlet and the fuel outlet are connected; the lubricating oil inlet of the lubricating oil radiator is connected to the outlet of the first heat exchange device; the lubricating oil outlet of the lubricating oil radiator is connected to the transmission system; the second bypass pipeline connects the fuel inlet and the fuel outlet.

[0009] In one embodiment, the first valve is a first flow regulating valve, which can adjust its opening degree according to the relationship between the lubricating oil temperature and the target high temperature limit value; the second valve is a second flow regulating valve, which can adjust its opening degree according to the relationship between the lubricating oil temperature and the target high temperature limit value; and the third valve is a third flow regulating valve, which can adjust its opening degree according to the relationship between the lubricating oil temperature and the target high temperature limit value.

[0010] In one embodiment, the first heat exchange device includes a servo fuel heater and an air-oil radiator; the oil inlet of the servo fuel heater is connected to the oil supply assembly via the oil supply line; the oil outlet of the servo fuel heater is connected to the oil inlet of the air-oil radiator; the oil outlet of the air-oil radiator is connected to the oil inlet of the fuel oil radiator; a first end of the first bypass line is connected to the oil supply line at a position upstream of the second flow control valve, and a second end of the first bypass line is connected to the line at the oil outlet of the air-oil radiator, so as to bypass the upstream side of the second flow control valve and the oil outlet of the air-oil radiator.

[0011] Another aspect of the present invention provides a method for testing the high temperature limit of lubricating oil, applied to the aforementioned lubricating oil supply system. The method includes: obtaining a target high temperature limit value required for the high temperature limit test and the real-time temperature of the lubricating oil at the lubricating oil outlet of the lubricating oil radiator; adjusting the opening of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve according to the relative relationship between the real-time lubricating oil temperature and the target high temperature limit value; and starting the timing of the high temperature limit test if the real-time lubricating oil temperature reaches the target high temperature limit value.

[0012] In one embodiment, adjusting the opening of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve based on the relative relationship between the real-time lubricating oil temperature and the target high-temperature limit value includes: closing the first flow regulating valve and opening the second flow regulating valve; if the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value is less than a preset temperature difference, increasing the opening of the first flow regulating valve and decreasing the opening of the second flow regulating valve; if the opening of the first flow regulating valve is 100%, the opening of the second flow regulating valve is 0%, and the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value is still less than the preset temperature difference, adjusting the opening of the third flow regulating valve.

[0013] In one embodiment, closing the first flow regulating valve and opening the second flow regulating valve further includes: closing the third flow regulating valve; adjusting the opening of the third flow regulating valve if the opening of the first flow regulating valve is 100%, the opening of the second flow regulating valve is 0%, and the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value is still less than the preset temperature difference includes: opening the third flow regulating valve if the opening of the first flow regulating valve is 100%, the opening of the second flow regulating valve is 0%, and the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value is less than the preset temperature difference; adjusting the opening of the third flow regulating valve according to the upward trend of the real-time lubricating oil temperature.

[0014] In one embodiment, adjusting the opening of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve according to the relative relationship between the real-time lubricating oil temperature and the target high-temperature limit value further includes: acquiring the lubricating oil heat generation and the total heat dissipation of the servo fuel heater, the air-lubricating oil radiator, and the fuel-lubricating oil radiator; and adjusting the opening of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve according to the lubricating oil heat generation and the total heat dissipation.

[0015] In one embodiment, the calorific value of the lubricating oil is obtained according to the following formula:

[0016] Q a =Q1+Q2+Q3

[0017] Among them, Q a Q1 is the heat generation of the lubricating oil, Q2 is the heat generation of the bearing, Q3 is the heat generation of the gearbox, and Q4 is the heat generation of the lubricating oil pump gear.

[0018] The total heat dissipation is obtained according to the following formula:

[0019]

[0020] Where Q4+Q5 is the total heat dissipation, Q4 is the heat dissipation of the servo fuel heater and the air lubricating oil cooler, Q5 is the heat dissipation of the fuel lubricating oil cooler, and W f Φ1 is the opening degree of the first flow regulating valve, Φ2 is the opening degree of the second flow regulating valve, Φ3 is the opening degree of the third flow regulating valve, ε1 is the flow resistance of the servo fuel heater and the air-lubricating oil radiator, ε2 is the flow resistance of the fuel-lubricating oil radiator, and ΔT is the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value.

[0021] The lubricating oil supply system of the present invention dynamically regulates the temperature of the lubricating oil through the first valve and the second valve, so as to reduce or completely block the heat dissipation of the lubricating oil. As a self-circulating system, the lubricating oil system temperature continues to rise under the continuous heating and insufficient cooling of the bearing until it reaches the high temperature limit value required for the airworthiness test. This can solve the problem that the lubricating oil temperature cannot be stably maintained at the high temperature limit value for a long time in the engine whole lubricating oil high temperature limit test. Attached Figure Description

[0022] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0023] Figure 1 This is a schematic diagram of an embodiment of the lubricating oil supply system according to the present invention;

[0024] Figure 2 This is a schematic flowchart of an embodiment of the lubricating oil high-temperature limitation test method according to the present invention;

[0025] Figure 3 This is a schematic flowchart of another embodiment of the lubricating oil high-temperature limitation test method according to the present invention. Detailed Implementation

[0026] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0027] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0028] A self-circulating system is a relatively closed system where the working fluid does not directly exchange with the outside environment and circulation is limited to the system's internal systems. The working envelope typically refers to various engine envelopes, such as the starting envelope, speed envelope, atmospheric temperature-pressure-altitude envelope, and operating attitude envelope.

[0029] The lubricating oil system of an aircraft engine is one of the important subsystems of an aircraft engine. The lubricating oil system needs to provide efficient cooling and lubrication for the engine and ensure that it can work normally under all operating conditions within the declared engine operating envelope. Bearings and transmission systems generate a lot of heat during operation. The lubricating oil flowing through the main bearings and transmission systems can prevent heat accumulation and avoid excessive damage to the bearings and transmission systems.

[0030] Figure 1 The lubricating oil supply system of this invention is shown as a subsystem within a lubricating oil system. This lubricating oil supply system is used for high-temperature limit testing of lubricating oil. According to the requirements of CCAR33.71, the airworthiness regulations for aircraft engines under CCAR33, to ensure that the damage and lifespan of lubricating oil system components and accessories meet expectations, the lubricating oil system should be able to operate stably for extended periods in a limited high-temperature oil environment without causing damage exceeding the limits. The high-temperature limit test is performed on a CCAR33.87 engine and lasts for 150 hours to ensure that the disassembly inspection of lubricating oil system components and accessories after the test does not show excessive damage or performance degradation. During the steady-state long-term rated operating conditions in the high-temperature limit test, the lubricating oil temperature needs to be maintained at the target high-temperature limit value.

[0031] The lubricating oil supply system of the present invention includes an oil supply assembly 14 for conveying self-circulating lubricating oil stored in an oil tank (not shown) and a first heat exchange device 15 for supplying lubricating oil to the transmission system after cooling the lubricating oil. The inlet of the first heat exchange device 15 is connected to the oil supply assembly 14. The outlet of the first heat exchange device 15 is connected to the transmission system (not shown). The transmission system includes bearings, a gearbox, and a lubricating oil pump gear. During the actual operation of an aero-engine, an increase in the temperature of the lubricating oil may lead to a decrease in the heat dissipation efficiency of the transmission system, causing overheating damage to related components. The first heat exchange device 15 includes a servo fuel heater 4 and an air-oil radiator 9. The lubricating oil inlet of the servo fuel heater 4 is connected to the oil supply assembly 14 via an oil supply line 16. Specifically, the first end of the oil supply line 16 is connected to the oil outlet of the servo oil supply assembly 14, and the second end of the oil supply line 16 is connected to the lubricating oil inlet 4-1 of the servo fuel heater 4. The lubricating oil outlet 4-2 of the servo fuel heater 4 and the lubricating oil inlet 9-1 of the air-oil radiator 9 are connected by the first lubricating oil connection pipe 18.

[0032] The lubricating oil supply system also includes a first bypass line 6, a first valve 7, and a second valve 8. The second valve 8 is located in the supply line 16. The first end of the first bypass line 6 is connected to the supply line 16 upstream of the second valve 8, and the second end is connected to the second lubricating oil connection line 19 of the lubricating oil outlet 9-2 of the air-oil radiator 9, bypassing the upstream side of the second valve 8 and the lubricating oil outlet 9-2 of the air-oil radiator 9, thus connecting the supply assembly 14 and the lubricating oil outlet 9-2 of the air-oil radiator 9. The first valve 7 is located in the first bypass line 6.

[0033] The first valve 7 is used to control the flow rate of lubricating oil flowing through the first bypass pipe 6, and the second valve 8 is used to control the flow rate of lubricating oil in the servo fuel heater 4 and the air lubricating oil radiator 9, so as to adjust the temperature of the lubricating oil and thus enable the temperature of the lubricating oil to reach the target high temperature limit value required for the high temperature limit test.

[0034] The lubricating oil supply system of the present invention dynamically regulates the temperature of the lubricating oil through the first valve 7 and the second valve 8, so as to reduce or completely block the heat dissipation of the lubricating oil. As a self-circulating system, the lubricating oil system temperature continues to rise under the continuous heating and insufficient cooling of the bearing until it reaches the high temperature limit value required for the airworthiness test. This can solve the problem that the lubricating oil temperature cannot be stably maintained at the high temperature limit value for a long time in the engine whole lubricating oil high temperature limit test.

[0035] In one embodiment, the lubricating oil supply system further includes a second heat exchange device. Specifically, the second heat exchange device is a fuel oil radiator 11. The fuel oil radiator 11 includes a lubricating oil inlet 11-1, a lubricating oil outlet 11-2, a fuel inlet 13-1, and a fuel outlet 13-2. The lubricating oil inlet 11-1 and the lubricating oil outlet 9-2 of the air-fuel radiator 9 are connected via a second lubricating oil connecting pipe 19. The lubricating oil outlet 11-2 of the fuel oil radiator 11 and the transmission system are connected via a third lubricating oil connecting pipe 20.

[0036] The lubricating oil supply system also includes a second bypass line 12 and a third valve 13. The second bypass line 12 connects the fuel inlet 13-1 and the fuel outlet 13-2. The third valve 13 is located on the second bypass line 12.

[0037] The third valve 13 and the second bypass line 12 constitute the bypass flow path of the controllable flow rate of the fuel-oil radiator 11. When the third valve 13 is fully open, the entire flow of fuel passes through the second bypass line 12 and no longer exchanges heat with the lubricating oil, thereby achieving the purpose of preventing the lubricating oil from dissipating heat.

[0038] The servo fuel heater 4, air-oil radiator 9, and fuel-oil radiator 11 in this invention are all accessories used for cooling the lubricating oil. The servo fuel heater 4 exchanges heat between the high-temperature lubricating oil and the servo fuel, preventing the servo fuel from thickening or freezing due to low temperatures, thus ensuring normal supply and combustion of the servo fuel in low-temperature environments. The air-oil radiator 9 dissipates the heat of the lubricating oil into the air through heat exchange between the air and the lubricating oil, thereby lowering the lubricating oil temperature. The fuel-oil radiator 11 transfers the heat of the lubricating oil to the fuel through heat exchange between the fuel and the lubricating oil, preventing the fuel from thickening or freezing due to low temperatures, thus ensuring normal supply and combustion of the fuel in low-temperature environments.

[0039] In one embodiment, the first valve 7 is a first flow regulating valve (hereinafter referred to as 7 in the reference numerals), the second valve 8 is a second flow regulating valve (hereinafter referred to as 8 in the reference numerals), and the third valve 13 is a third flow regulating valve (hereinafter referred to as 13 in the reference numerals). The first flow regulating valve 7, the second flow regulating valve 8, and the third flow regulating valve 13 can all adjust their opening degree according to the relationship between the lubricating oil temperature and the target high-temperature limit value. The flow regulating valves can control the flow rate of the medium in the pipeline by controlling the valve opening degree. The flow regulating valves can be ball valves, butterfly valves, or other types of regulating valves, and the control type can be electric control, hydraulic control, or pneumatic control; this invention is not limited to any of these types. The first flow regulating valve 7, the second flow regulating valve 8, and the third flow regulating valve 13 can be connected to a control device to achieve dynamic adjustment of the opening degree.

[0040] The opening degree of the first flow regulating valve 7, the second flow regulating valve 8, and the third flow regulating valve 13 can be expressed as a percentage. An opening degree of 100% indicates that the valve is fully open; an opening degree of 0% indicates that the valve is fully closed, and the medium (in this invention, lubricating oil) cannot pass through the valve.

[0041] like Figure 1 As shown, the oil supply assembly 14 includes an oil supply pump 2, a return oil pump 1, and an oil supply filter 3. The inlet of the oil supply pump 2 and the outlet of the return oil pump 1 are connected to the lubricating oil tank, and the oil supply filter 3 is connected to the outlet of the oil supply pump 2. When the first flow regulating valve 7 and the third flow regulating valve 13 are fully closed, the lubricating oil, after being pressurized by the oil supply pump 2 and filtered by the oil supply filter 3, flows sequentially through the servo fuel heater 4, the air-lubricating oil radiator 9, and the fuel-lubricating oil radiator 11 for cooling, and then supplies oil to the bearing cavity and the squeeze oil film.

[0042] Continue to refer to Figure 1The lubricating oil supply system also includes a first bypass three-way valve 5 and a second bypass three-way valve 10. The first bypass three-way valve 5 is located in the oil supply line 16 and upstream of the second flow regulating valve 8. The second bypass three-way valve 6 is located in the second lubricating oil connection line 19. The first bypass line 6 is connected between the upstream side of the second regulating valve 8 and the lubricating oil outlet 9-2 of the air-oil radiator 9 through the first bypass three-way valve 5 and the second bypass three-way valve 10.

[0043] The lubricating oil supply system also includes a one-way valve 17 installed in the oil supply line 16. The one-way valve 17 is located upstream of the first bypass three-way valve 5, ensuring that the lubricating oil can only flow along... Figure 1 The flow should follow the direction indicated by the arrow to prevent lubricating oil from flowing back into the oil supply filter 3.

[0044] In another embodiment, the servo fuel heater 4, air-oil radiator 9, and fuel-oil radiator 11 are bypassed. Specifically, a bypass pipeline is provided between the oil inlet 4-1 and oil outlet 4-2 of the servo fuel heater 4, between the oil inlet 9-1 and oil outlet 9-2 of the air-oil radiator 9, and between the oil inlet 11-1 and oil outlet 11-2 or between the fuel inlet 13-1 and fuel inlet 13-2 of the fuel-oil radiator 11. A flow regulating valve is installed on each bypass pipeline, enabling precise control of the heat dissipation efficiency of the three radiators with higher accuracy.

[0045] In such Figure 1 In the embodiment shown, by bypassing the servo fuel heater 4 and the air lubricating oil radiator 9, the lubricating oil can be controlled to reach the target high temperature limit value as much as possible. Furthermore, by bypassing the fuel inlet 13-1 and fuel outlet 13-2 of the fuel lubricating oil radiator 11, all lubricating oil temperature control scenarios can be covered, and fewer pipes and valves are required, resulting in better cost control.

[0046] Figure 2 The following is a detailed flowchart of an embodiment of the lubricating oil high-temperature limitation test method of the present invention. The lubricating oil high-temperature limitation test method of the present invention is applied to a lubricating oil supply system. In conjunction with the above embodiment of the lubricating oil supply system, the lubricating oil high-temperature limitation test method includes steps S100 to S300:

[0047] In step S100, the target high temperature limit value required for the high temperature limit test and the real-time temperature of the lubricating oil at the lubricating oil outlet of the lubricating oil radiator 11 are obtained.

[0048] In step S200, the opening degrees of the first flow regulating valve 7, the second flow regulating valve 8, and the third flow regulating valve 13 are adjusted according to the relative relationship between the real-time lubricating oil temperature and the target high temperature limit value.

[0049] In step S300, if the real-time temperature of the lubricating oil reaches the target high-temperature limit value, the high-temperature limit test is started.

[0050] Optionally, in step S100, the real-time temperature of the lubricating oil is monitored by installing a temperature sensor (not shown) at the lubricating oil outlet of the lubricating oil radiator 11, such as at the lubricating oil outlet 11-2 and the third lubricating oil connection pipe 20.

[0051] Figure 3 The following is a detailed flowchart of another embodiment of the lubricating oil high-temperature limitation test method of the present invention. Figure 3 As shown, the lubricating oil high-temperature limitation test method of the present invention further includes steps S101 to S901:

[0052] In step S101, the engine is started to the target test rated thrust and kept stable. The target high-temperature limit value required for the high-temperature limit test and the real-time lubricating oil temperature at the lubricating oil outlet of the fuel oil radiator 11 are obtained. In this step, to avoid overheating of the lubricating oil due to the air lubricating oil radiator 9 being short-circuited at low operating conditions such as ground idle, the self-circulating heating function of the present invention should be activated after the engine reaches a higher target operating condition and stabilizes.

[0053] In step S201, the first flow regulating valve 7 is closed, the second flow regulating valve 8 is opened, and the third flow regulating valve 13 is closed. That is, the opening degree of the first flow regulating valve 7 and the third flow regulating valve 13 is 0%, and the opening degree of the second flow regulating valve 8 is 100%. At this time, the lubricating oil supply system is in the reference state, and the lubricating oil is normally cooled.

[0054] In step S301, it is determined whether the temperature difference between the real-time temperature of the lubricating oil and the target high-temperature limit value is less than the preset temperature difference;

[0055] If the temperature difference between the real-time temperature of the lubricating oil and the target high-temperature limit value is greater than or equal to the preset temperature difference, then proceed to step S401.

[0056] If the temperature difference between the real-time temperature of the lubricating oil and the target high-temperature limit value is less than the preset temperature difference, then step S901 is executed.

[0057] In step S401, the opening degree of the first flow regulating valve 7 is increased, and the opening degree of the second flow regulating valve 8 is decreased.

[0058] In step S501, it is determined whether the opening degree of the first flow regulating valve 7 is 100% and whether the opening degree of the second flow regulating valve 8 is 0%.

[0059] If the opening of the first flow regulating valve 7 is 100% and the opening of the second flow regulating valve 8 is 0%, then step S601 is executed; at this time, the servo fuel heater 4 and the air lubricating oil radiator 9 are completely bypassed and short-circuited, and the lubricating oil can achieve no heat dissipation.

[0060] If the opening degree of the first flow regulating valve 7 is not 100% or the opening degree of the second flow regulating valve 8 is not 0%, then step S301 is executed.

[0061] In step S601, the third flow regulating valve 13 is opened. Furthermore, the opening degree of the third flow regulating valve 13 can be dynamically adjusted according to the rising trend of the lubricating oil temperature in real time, thereby dynamically adjusting the fuel flow rate that exchanges heat with the lubricating oil in the fuel-oil radiator 11.

[0062] In step S701, the total heat generation of the lubricating oil and the heat dissipation of the servo fuel heater 4, the air lubricating oil radiator 9 and the fuel lubricating oil radiator 11 are obtained.

[0063] In step S801, the opening degrees of the first flow regulating valve 7, the second flow regulating valve 8, and the third flow regulating valve 13 are adjusted based on the sum of the heat generated and the heat dissipated by the lubricating oil. In this step, the valve opening degrees can be further adjusted in conjunction with the ambient temperature, and can be adjusted online via a control device.

[0064] In step S901, if the heat generated by the lubricating oil equals the total heat dissipation, and the real-time temperature of the lubricating oil remains stable at slightly above the target high-temperature limit value, then the high-temperature limit test is started. Otherwise, continue with step S801.

[0065] In steps S801 and S901, the calorific value of the lubricating oil is obtained according to equation (1):

[0066] Q a =Q1+Q2+Q3 (1)

[0067] Among them, Q a Q1 represents the heat generated by the lubricating oil, Q2 represents the heat generated by the bearing, Q3 represents the heat generated by the gearbox, and Q4 represents the heat generated by the lubricating oil pump gear.

[0068] The total heat dissipation is obtained according to equation (2):

[0069]

[0070] Where Q4 + Q5 is the total heat dissipation, Q4 is the heat dissipation of the servo fuel heater 4 and the air lubricating oil radiator 9, and Q5 is the heat dissipation of the fuel lubricating oil radiator 11. W f Φ1 is the opening degree of the first flow regulating valve 7, Φ2 is the opening degree of the second flow regulating valve 8, Φ3 is the opening degree of the third flow regulating valve 13, ε1 is the flow resistance of the servo fuel heater 4 and the air lubricating oil radiator 9, ε2 is the flow resistance of the fuel lubricating oil radiator 11, and ΔT is the temperature difference between the real-time lubricating oil temperature and the target high temperature limit value.

[0071] ΔT=TTmax

[0072] Where T is the real-time temperature of the lubricating oil, T max The target high temperature limit value.

[0073] According to the above relationship, in step S401, by increasing the opening of the first flow regulating valve 7 and decreasing the opening of the second flow regulating valve 8, the heat dissipation Q4 of the servo fuel heater 4 and the air-oil radiator 9 decreases, while the heat dissipation Q5 of the fuel-oil radiator 11 increases, and the heat generation Q of the lubricating oil increases. a Decrease, dynamic value Q a -Q4-Q5 saw steady growth.

[0074] In step S601, the first flow regulating valve 7 is fully opened, the second flow regulating valve 8 is fully closed, and the third flow regulating valve 13 is opened, i.e., Φ1 = 100% and Φ2 = 0%. The opening degree Φ3 of the third flow regulating valve 13 is increased, so that the heat dissipation Q4 of the servo fuel heater 4 and the air lubricating oil radiator 9 is 0, the heat dissipation Q5 of the fuel lubricating oil radiator 11 is reduced, and the heat generation Q of the lubricating oil is reduced. a Decrease, dynamic value Q a -Q4-Q5 rise steadily until T=T max .

[0075] Through the aforementioned high-temperature limit test method for lubricating oil, the lubricating oil that has not been cooled or has not been sufficiently cooled in the lubricating oil supply system further enters the bearing cavity to cool and lubricate the bearing and remove a large amount of heat. Since the lubricating oil system is an approximately self-circulating system, under the continuous heating and insufficient cooling of the bearing, the temperature of the entire flow path of the lubricating oil system will rise rapidly until it reaches the high-temperature limit of the test target. Based on the lubricating oil heat generation power under the target test conditions, by adjusting the opening of the first flow regulating valve 7, the second flow regulating valve 8, and the third flow regulating valve 13, the heat dissipation power of the three accessories with lubricating oil cooling function is made equal to the lubricating oil heat generation power, thus maintaining a relatively stable lubricating oil temperature. This solves the problem of difficulty in maintaining a stable lubricating oil system temperature during the engine lubricating oil high-temperature limit test.

[0076] The target high-temperature limit value required for the high-temperature limitation test is determined according to the actual airworthiness test conditions, and this invention does not impose any restrictions. Real-time lubricating oil temperature reaching the target high-temperature limit value can be understood as: the real-time lubricating oil temperature remaining stably within a high-temperature fluctuation range with the target high-temperature limit value as the median value within a preset time period, i.e., T∈[T...]. max -t,T max +t]. The preset duration and high temperature fluctuation range can be determined according to the actual test requirements and conditions.

[0077] In step S301, the preset temperature difference is t, and the upward trend of the lubricating oil temperature can be observed. If the real-time lubricating oil temperature rises rapidly and approaches the high-temperature limit value or the high-temperature limit range, the opening of the second flow regulating valve 8 is increased, and the opening of the first flow regulating valve 7 is decreased to slow down the rate of increase of the real-time lubricating oil temperature. This continues until the real-time lubricating oil temperature stabilizes within the high-temperature fluctuation range. If the real-time lubricating oil temperature rises slowly and the temperature limit margin is large, step S401 is continued.

[0078] The lubricating oil high-temperature limit test method of the present invention can dynamically adjust the real-time temperature of the lubricating oil by adjusting the opening degree of three valves online. Further, the lubricating oil high-temperature limit test method of the present invention includes a processor and a memory. The memory stores non-transitory computer instructions, which, when executed by the processor, execute the lubricating oil high-temperature limit test method of any embodiment of the present invention. The storage medium of the present invention is used to store non-transitory computer instructions, which, when executed, execute the lubricating oil high-temperature limit test method of any embodiment of the present invention.

[0079] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A lubricating oil supply system for use in a high-temperature limit test of lubricating oil, the lubricating oil supply system comprising a supply component for conveying self-circulating lubricating oil stored in a lubricating oil tank and a first heat exchange device for supplying the lubricating oil to a transmission system after cooling the lubricating oil. The inlet of the first heat exchange device is connected to the oil supply assembly; The outlet of the first heat exchange device is connected to the transmission system; Its features are, The lubricating oil supply system further includes a first bypass pipeline, a first valve, and a second valve; wherein... The first bypass line connects the oil supply assembly and the outlet of the first heat exchange device; The first valve is installed in the first bypass pipeline; The second valve is installed in the oil supply line connecting the oil supply assembly and the inlet of the first heat exchange device; The first valve and the second valve are used to control the flow rate of lubricating oil flowing through the first bypass pipeline and the first heat exchange device, respectively, so as to adjust the temperature of the lubricating oil and thus enable the temperature of the lubricating oil to reach the target high temperature limit value required for the high temperature limit test.

2. The lubricating oil supply system as described in claim 1, characterized in that, The lubricating oil supply system also includes a second heat exchange device; The second heat exchange device is connected to the outlet of the first heat exchange device and the transmission system; The lubricating oil supply system also includes a second bypass pipeline and a third valve; The second bypass pipeline connects the inlet and outlet of the heat exchange medium that exchanges heat with the lubricating oil inside the second heat exchange device; The third valve is located in the second bypass pipeline.

3. The lubricating oil supply system as described in claim 2, characterized in that, The second heat exchange device is a lubricating oil radiator; The lubricating oil radiator includes an oil inlet, an oil outlet, a fuel inlet, and a fuel outlet. The oil inlet and the oil outlet are connected, and the fuel inlet and the fuel outlet are connected. The lubricating oil inlet of the lubricating oil radiator is connected to the outlet of the first heat exchange device; The lubricating oil outlet of the lubricating oil radiator is connected to the transmission system; The second bypass line connects the fuel inlet and the fuel outlet.

4. The lubricating oil supply system as described in claim 3, characterized in that, The first valve is a first flow regulating valve, which can adjust its opening degree according to the relationship between the temperature of the lubricating oil and the target high temperature limit value; The second valve is a second flow regulating valve, which can adjust its opening degree according to the relationship between the temperature of the lubricating oil and the target high temperature limit value; The third valve is a third flow regulating valve, which can adjust its opening degree according to the relationship between the temperature of the lubricating oil and the target high temperature limit value.

5. The lubricating oil supply system as described in claim 4, characterized in that, The first heat exchange device includes a servo fuel heater and an air-oil radiator; The lubricating oil inlet of the servo fuel heater is connected to the oil supply pipeline and the oil supply assembly; The lubricating oil outlet of the servo fuel heater is connected to the lubricating oil inlet of the air-oil radiator; The lubricating oil outlet of the air lubricating oil radiator is connected to the lubricating oil inlet of the fuel lubricating oil radiator; The first end of the first bypass line is connected to the oil supply line located upstream of the second flow regulating valve, and the second end of the first bypass line is connected to the oil outlet of the air-oil radiator to bypass the upstream side of the second flow regulating valve and the oil outlet of the air-oil radiator.

6. A method for testing the high-temperature limitation of lubricating oil, characterized in that, The lubricating oil high-temperature limitation test method, applied to the lubricating oil supply system as described in claim 5, includes: Obtain the target high-temperature limit value required for the high-temperature limit test and the real-time temperature of the lubricating oil at the lubricating oil outlet of the lubricating oil radiator; Based on the relative relationship between the real-time lubricating oil temperature and the target high-temperature limit value, adjust the opening of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve; If the real-time temperature of the lubricating oil reaches the target high-temperature limit value, then the high-temperature limit test will begin.

7. The method for testing the high-temperature limitation of lubricating oil as described in claim 6, characterized in that, The step of adjusting the opening of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve according to the relative relationship between the real-time lubricating oil temperature and the target high-temperature limit value includes: Close the first flow regulating valve and open the second flow regulating valve; If the temperature difference between the real-time temperature of the lubricating oil and the target high-temperature limit value is less than the preset temperature difference, then the opening of the first flow regulating valve is increased and the opening of the second flow regulating valve is decreased. If the opening of the first flow regulating valve is 100%, the opening of the second flow regulating valve is 0%, and the temperature difference between the real-time temperature of the lubricating oil and the target high-temperature limit value is still less than the preset temperature difference, then the opening of the third flow regulating valve is adjusted.

8. The method for testing the high temperature limit of lubricating oil as described in claim 7, characterized in that, The step of closing the first flow regulating valve and opening the second flow regulating valve further includes: Close the third flow regulating valve; If the opening degree of the first flow regulating valve is 100%, the opening degree of the second flow regulating valve is 0%, and the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value is still less than the preset temperature difference, then adjusting the opening degree of the third flow regulating valve includes: If the opening degree of the first flow regulating valve is 100%, the opening degree of the second flow regulating valve is 0%, and the temperature difference between the real-time temperature of the lubricating oil and the target high temperature limit value is less than the preset temperature difference, then the third flow regulating valve is opened. The opening degree of the third flow regulating valve is adjusted according to the rising trend of the real-time temperature of the lubricating oil.

9. The method for testing the high-temperature limitation of lubricating oil as described in claim 7 or 8, characterized in that, The step of adjusting the openings of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve based on the relative relationship between the real-time lubricating oil temperature and the target high-temperature limit value further includes: The heat generation of the lubricating oil and the total heat dissipation of the servo fuel heater, the air-lubricating oil radiator, and the fuel-lubricating oil radiator are obtained; The opening degrees of the first flow regulating valve, the second flow regulating valve, and the third flow regulating valve are adjusted according to the sum of the heat generated by the lubricating oil and the heat dissipation.

10. The method for testing the high-temperature limitation of lubricating oil as described in claim 9, characterized in that, The calorific value of the lubricating oil is obtained according to the following formula: Q a Q1+Q2+Q3 Among them, Q a Q1 is the heat generation of the lubricating oil, Q2 is the heat generation of the bearing, Q3 is the heat generation of the gearbox, and Q4 is the heat generation of the lubricating oil pump gear. The total heat dissipation is obtained according to the following formula: Where Q4+Q5 is the total heat dissipation, Q4 is the heat dissipation of the servo fuel heater and the air lubricating oil cooler, Q5 is the heat dissipation of the fuel lubricating oil cooler, and W f Φ1 is the opening degree of the first flow regulating valve, Φ2 is the opening degree of the second flow regulating valve, Φ3 is the opening degree of the third flow regulating valve, ε1 is the flow resistance of the servo fuel heater and the air-lubricating oil radiator, ε2 is the flow resistance of the fuel-lubricating oil radiator, and ΔT is the temperature difference between the real-time lubricating oil temperature and the target high-temperature limit value.

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