Connecting pipe type high-altitude test bed and standard atmospheric environment simulation control method

Abstract

The invention discloses a connecting pipe type high-altitude test bed and a standard atmospheric environment simulation control method, relates to the technical field of engine benchmark testing, and solves the problem that the engine benchmark test result measured by the test bed is not accurate enough due to large deviation between the engine air inlet condition and the standard atmospheric environment. The medium-pressure gas source system, the main gas inlet pipeline, the engine gas inlet path and the exhaust bypass are arranged, the accuracy of the inlet pressure of the engine can be guaranteed through cooperative work of the main path adjusting valve and the secondary path adjusting valve, and the bypass adjusting valve does not pass through the engine, so that the characteristic that the bypass adjusting valve is decoupled from the engine is utilized; the pressure adjusting time is shortened, and the rapidity and the accuracy of the pressure are improved to a certain degree at the same time. In addition, closed-loop control based on rotating speed compensation interpolation and closed-loop control based on PID are adopted for controlling the main path adjusting valve and the secondary path adjusting valve in real time at the same time, and the working stability of the engine and the rapidity of flow response are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of engine benchmark testing technology, and in particular to a tubular high-altitude test bench and a standard atmospheric environment simulation control method. Background Technology

[0002] The standard atmospheric environment for benchmark testing of an aero-engine (hereinafter referred to as engine) refers to the environment at the engine inlet that must be maintained under standard atmospheric conditions during benchmark performance testing to eliminate the influence of environmental fluctuations and ensure the accuracy and comparability of test results. Specifically, the parameters of the standard atmospheric environment under static conditions at sea level are: ambient pressure of 101.325 kPa, ambient temperature of 15 degrees Celsius (i.e., 288.15 Kelvin), and relative humidity of 0%. Only by conducting tests under such standard atmospheric conditions can the objectivity and comparability of engine performance results be guaranteed, thereby providing a reliable reference for engine design, improvement, and evaluation.

[0003] Traditional ground-based engine test benches typically employ natural air intake for benchmark engine testing, meaning the engine draws air directly from the environment surrounding the test bench. However, this method has several drawbacks. First, intake air temperature is affected by various factors such as seasonal changes, day-night cycles, and weather conditions, making it impossible to consistently maintain a standard sea-level temperature. For example, in hot summer weather, intake air temperature may rise significantly, while in cold winter weather or during nighttime low temperatures, it may drop noticeably. This temperature fluctuation can alter engine performance parameters, affecting the accuracy of test results. Second, intake pressure also fluctuates with atmospheric pressure, making it impossible to consistently maintain a standard sea-level pressure value. Atmospheric pressure fluctuations can be influenced by weather systems, altitude changes, and other factors, which also affect key performance indicators such as engine intake volume and combustion efficiency. In summary, the significant deviation between engine intake conditions and the standard atmospheric environment is the fundamental reason for the inaccurate benchmark engine test results measured by the test bench.

[0004] Therefore, a tubular high-altitude test stand and a standard atmospheric environment simulation control method are needed. Summary of the Invention

[0005] To address the problem in existing technologies where engine intake conditions deviate significantly from standard atmospheric conditions, leading to inaccurate benchmark test results from test benches, this invention provides a pipe-connected high-altitude test bench and a standard atmospheric environment simulation control method. This method actively compensates for engine intake demand via the test bench, resolving the issue of large deviations between intake conditions and standard atmospheric conditions during atmospheric extraction. Furthermore, the coordinated operation of the main and secondary regulating valves ensures the accuracy of the engine inlet pressure. The specific technical solution is as follows: A tubular high-altitude test stand includes: Medium-pressure air source system: includes a medium-pressure air tank and a first switching valve 102, wherein the medium-pressure air tank is connected to the main air intake pipe through the switching valve; Main intake pipe: includes a first pressure regulating valve, a second pressure regulating valve and a first pressure rake, wherein the first pressure regulating valve is located between the main intake pipe and the medium-pressure air source system, the first pressure rake is located between the first pressure regulating valve and the second pressure regulating valve, and the main intake pipe is connected to the engine intake passage through the second pressure regulating valve. Engine intake passage: includes a second pressure rake and an intake pipe. The second pressure rake is located on the intake pipe and is used to test the pressure of the intake pipe. The output end of the intake pipe is connected to the engine. Exhaust bypass: Connected to the main intake pipe and located between the first pressure regulating valve and the second pressure regulating valve, it does not pass through the engine. The exhaust bypass is equipped with a third pressure regulating valve and a third pressure rake in sequence. The third pressure rake is used to test the air pressure after being regulated by the third pressure regulating valve.

[0006] Preferably, it also includes an air heating system and an air cooling system, wherein: The air heating system includes a second switching valve, an electric heater, and a third switching valve. The electric heater is connected to the main air intake pipe through the first and third switching valves, and the connection points of the second and third switching valves to the main air intake pipe are both located between the first and second pressure regulating valves. The air cooling system includes a fourth switching valve, an air wave generator, and a fifth switching valve. The air wave generator is connected to the main air intake pipe through the fourth and fifth switching valves. The connection between the fourth switching valve and the main air intake pipe is located between the first switching valve and the medium-pressure air source system. The connection between the fifth switching valve and the main air intake pipe is located between the first pressure regulating valve and the second pressure regulating valve.

[0007] Preferably, it also includes a first air filter, which is located between the first switch valve and the medium-pressure air source system, specifically at the outlet of the medium-pressure air tank.

[0008] Preferably, it also includes a second air filter, which is located between the exhaust bypass and the second pressure regulating valve, specifically at the air inlet of the intake pipe. The gas processed by the main pipeline is filtered by the second air filter before being input into the engine intake pipe.

[0009] Preferably, it further includes a first temperature rake and a second temperature rake, wherein the first temperature rake is disposed between the first pressure regulating valve and the second pressure regulating valve, and the second temperature rake is disposed on the air intake pipe.

[0010] Preferably, the third pressure regulating valve and the second pressure regulating valve are equal-diameter fast-reading opening valves.

[0011] A standard atmospheric environment simulation and control method, applied to the above-mentioned tubular high-altitude test stand, includes the following steps: When the first switch valve is opened, the air in the medium-pressure air tank enters the main air intake pipe, and the opening of the first pressure regulating valve is controlled so that the air pressure measured by the first pressure rake is more than 3 times the simulated air intake pressure of 103.23 kPa. By adjusting the outlet temperatures of the air cooling system and the air heating system to ensure that the temperature measured by the first temperature rake remains within 15℃±1.5℃ after mixing; The engine test bench sets a speed threshold. When the engine speed is less than the set threshold, the speed compensation control strategy controls the opening of the second and third pressure regulating valves to maintain the temperature measured by the second temperature rake at 15℃ and the second pressure rake at 101kPa, thereby ensuring that the engine is always in a standard environment. If the engine speed exceeds the set threshold, it is determined to be in a steady-state operation, and the PID closed-loop control is switched.

[0012] The preferred control process based on the speed compensation control strategy is as follows: To determine if the engine is in the starting phase, a lookup list of pressure at a specified speed n and the opening value of the main second pressure regulating valve is used. Then, by calculating the engine intake pressure value, and based on the intake pipe pressure value and the engine speed, the main second pressure regulating valve is dynamically adjusted to different opening degrees. The opening degree of the secondary third pressure regulating valve follows the change of the main valve, satisfying the condition that the opening ratio of the second pressure regulating valve + the opening ratio of the third pressure regulating valve = 100%.

[0013] Preferably, the closed-loop control process is as follows: S1: Input the target and actual values; S2: Initialize PID parameters; S3: Calculate the third error coefficient and the target error value; S4: Determine if the error value is greater than the acceptable error range. If so, the control quantity is zero; otherwise, start PID calculation and provide the control quantity.

[0014] Preferably, the process of ensuring that the temperature measured by the first temperature rake is maintained within 15℃±1.5℃ is as follows: When the temperature is above 15℃±1.5℃, the temperature is lowered by air cooling control method. The air cooling control method is as follows: by opening the fourth switch valve, the air in the medium pressure gas tank enters the air wave machine through the main air intake, and then the fifth switch valve is opened to connect the air outlet of the air wave machine to the main air intake system, so that air enters the air wave machine. When the temperature is below 15℃±1.5℃, the temperature is raised by air heating control method. Specifically, the air heating control method is as follows: by opening the second switch valve, air from the medium-pressure gas tank enters the electric heater through the main air intake, and by opening the third switch valve, the air outlet of the electric heater is connected to the main air intake system.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention includes a medium-pressure air source system, a main intake pipe, an engine intake path, and an exhaust bypass. The medium-pressure air source system includes a medium-pressure air tank and a first switching valve 102. The medium-pressure air tank is connected to the main intake pipe via the switching valve. The main intake pipe includes a first pressure regulating valve, a second pressure regulating valve, and a first pressure rake. The first pressure regulating valve is located between the main intake pipe and the medium-pressure air source system, and the first pressure rake is located between the first and second pressure regulating valves. The main intake pipe is connected to the engine intake path via the second pressure regulating valve. The engine intake path includes a second pressure rake and an intake pipe. The second pressure rake is located on the intake pipe and is used to test the pressure of the intake pipe. The output end of the intake pipe is connected to the engine. The exhaust bypass is connected to the main intake pipe and is located between the first and second pressure regulating valves, bypassing the engine. A third pressure regulating valve and a third pressure rake are sequentially arranged on the exhaust bypass. The third pressure rake is used to test the air pressure after being regulated by the third pressure regulating valve. In summary, the present invention can ensure the accuracy of engine inlet pressure through the coordinated operation of the main regulating valve and the secondary regulating valve.

[0016] 2. Conventional engines exhibit significant inertia in inlet pressure and flow rate during the start-up phase, resulting in long adjustment times and slow responses. This is primarily due to the abrupt changes in intake air demand caused by rapid changes in engine speed, which conventional control strategies handle with slow valve response. The speed compensation control and PID closed-loop composite control proposed in this invention effectively address the issue of rapid engine response to compensated inlet flow and pressure at different stages. Furthermore, by utilizing the bypass regulating valve's decoupling from the engine, it reduces pressure adjustment time and, to a certain extent, simultaneously improves both the speed and accuracy of pressure regulation.

[0017] 3. The control method proposed in this invention simultaneously employs closed-loop control based on speed compensation interpolation and closed-loop control based on PID to perform real-time control of both the main and secondary regulating valves, ensuring engine stability and rapid flow response. The lookup-table linear closed-loop control adjusts the opening of the main and bypass regulating valves, ensuring engine stability and preventing instability caused by abnormal engine speed regulation. When the error is small, this regulating valve is used to correct the pressure, ensuring pressure accuracy. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of a tubular high-altitude test bench system; Figure 2 A schematic diagram of the standard atmospheric environment control method for simulating an aero-engine on a tubular high-altitude test stand. Figure 3 Here is the PID control flowchart; Figure 4 This is a diagram illustrating the pressure adjustment principle. In the picture: 101 - Medium-pressure gas tank; 102 - First switch valve; 103 - First air filter; 201-First pressure regulating valve, 202-Second air filter, 203-First pressure rake, 204-First temperature rake; 301 - Second switching valve, 302 - Electric heater, 303 - Third switching valve; 401 - Airwave Unit, 402 - Fourth Switch Valve, 403 - Fifth Switch Valve; 501-Second pressure regulating valve, 502-Second temperature rake, 503-Second pressure rake, 504-Inlet pipe, 504-Inlet pipe; 601 - Third pressure regulating valve; 602 - Third pressure rake; 700-Engine. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0023] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] In one embodiment of the present invention, a tubular high-altitude test stand is provided, such as... Figure 1 As shown, it includes: 1. Medium-pressure air source system: including medium-pressure air tank 101, first switch valve 102, and first air filter 103; 2. Main intake pipe: including first pressure regulating valve 201, second air filter 202, first pressure rake 203, and first temperature rake 204; 3. Air heating system: including a second switching valve 301, an electric heater 302, and a third switching valve 303; 4. Air refrigeration system: including air wave generator 401, fourth switching valve 402, and fifth switching valve 403; 5. Engine intake passage: including second pressure regulating valve 501, second temperature rake 502, second pressure rake 503, intake pipe 504, engine 700; intake pipe 504; 6. Exhaust bypass: includes third pressure regulating valve 601 and third pressure rake 602; 4. Test bench adjustment system: including adjustment devices; 4. Engine: Includes the engine block.

[0025] The test bench adjustment system described in this embodiment consists of a medium-pressure air source system, a main intake system, an air heating system, an air cooling system, an engine intake passage, an exhaust bypass and valve, and an adjustment system. The test bench controls the medium-pressure air source system to supply dry air (or ambient temperature air) to the air heating system or air cooling system via the main intake system. This air must be clean and have an intake pressure exceeding the engine's maximum intake pressure requirement. The test bench adjustment system uses closed-loop control of the heating system or cryogenic system to adjust the air in the main intake pipe to the target temperature, thereby providing the engine with air meeting national atmospheric standards. Simultaneously, the open-loop control of the bypass releases excess air, ensuring the speed and accuracy of the intake environment. Since the air temperature, humidity, and cleanliness of the test bench intake conditions are constant, pressure adjustment is the primary consideration during testing. The following is a brief description of the pressure adjustment process: The second pressure regulating valve is a fast-opening valve, also known as the main valve. The test bench adjustment system adjusts the pressure value measured by the second pressure rake 503 to the target pressure, controlling the opening of the second pressure regulating valve 501 to change, thus altering the engine speed at 700 rpm. This affects the pressure value measured by the second pressure rake 503, and the control system again changes the opening of the second pressure regulating valve 501. This process repeats until pressure equilibrium is reached. The entire dynamic process of pressure regulation can be summarized as follows: the main valve opening changes, the engine speed changes, the engine intake pressure changes, the main valve opening changes again, and after multiple rounds of changes in engine speed and engine intake pressure, these physical quantities tend to stabilize, and a new equilibrium state is reached between engine speed and engine intake pressure. Due to the large rotor inertia of the engine, the transition time from the initial stage to the target stage of intake pressure is relatively long, resulting in a relatively slow pressure regulation time.

[0026] The third pressure regulating valve 601 is also a quick-opening valve, i.e., a bypass regulating valve. This regulating valve and the second pressure regulating valve 501 are equal-diameter quick-opening valves, and the regulating range of the bypass regulating valve is equal to that of the main regulating valve. The third pressure regulating valve 601 and the second pressure regulating valve form a pressure regulating system, i.e., this path, with the purpose of quickly adjusting pressure and improving control accuracy. When the engine speed changes, the engine inlet pressure changes, thus affecting the opening of the second pressure regulating valve 501. Simultaneously, the opening of the third pressure regulating valve 601 also changes, allowing residual gas entering the engine to be discharged into the atmosphere through the bypass passage, resulting in a rapid response of the main pressure.

[0027] The pressure regulation process of the main regulating valve and the bypass regulating valve has been briefly described above. The control method for the air intake conditions of this test bench, as described in this patent, will be briefly described below. The specific steps are as follows: Work process: Open the first switch valve 102, and the air in the medium pressure air tank 101 enters the main air intake pipe through the first air filter 103. The air is controlled by the opening of the first pressure regulating valve 201 so that the air pressure measured by the first pressure rake 203 is more than 3 times the simulated air intake pressure of 103.23 kPa. By adjusting the outlet temperatures of the air cooling system (see Air Cooling Control Method) and the air heating system (see Air Heating Control Method), the mixed temperature can ensure that the temperature measured by the first temperature rake 204 remains within 15℃ ± 1.5℃. When the engine test bench sets a speed threshold, if the engine speed is less than the set threshold (the threshold can be changed according to the engine model), the opening of the second pressure regulating valve 501 and the third pressure regulating valve 601 is controlled according to the speed compensation control strategy (details of the speed compensation control strategy are explained in detail) to maintain the temperature measured by the second temperature rake 502 at 15℃ and the second pressure rake 503 at 101kPa, thereby ensuring that the engine 700 is always in a standard environment. If the engine speed is greater than the set threshold, it is judged to be in a steady-state operating state, and then the closed-loop control is switched (details of the control are explained in the notes of the speed compensation control strategy).

[0028] In one embodiment of the present invention, a standard atmospheric environment simulation and control method is provided, comprising the following steps: Step 1: Open the first switch valve, and the air in the medium-pressure air tank enters the main air intake pipe. The opening of the first pressure regulating valve is controlled so that the air pressure measured by the first pressure rake is more than 3 times the simulated air intake pressure of 103.23 kPa. Step 2: Adjust the outlet temperatures of the air cooling system and the air heating system to ensure that the temperature measured by the first temperature rake remains within 15℃±1.5℃ after mixing. Step 3: Set the engine speed threshold on the engine test bench. When the engine speed is less than the set threshold, control the opening of the second and third pressure regulating valves according to the speed compensation control strategy to maintain the temperature measured by the second temperature rake at 15℃ and the second pressure rake at 101kPa, thereby ensuring that the engine is always in a standard environment. Step 4: If the engine speed is greater than the set threshold, it is determined to be in a steady-state operation, and then the PID closed-loop control is switched.

[0029] During engine startup, the intake air requirements change abruptly due to the rapid change in engine speed. However, once the engine reaches a stable operating condition, the intake air requirements stabilize. This embodiment addresses the conflict between rapid response and stable adjustment accuracy by employing two different algorithms in the control strategy to precisely ensure the engine's intake conditions. The control strategy is as follows: during engine startup, open-loop control with speed compensation is used to control the engine's intake conditions. During the engine's steady-state and operating condition transition phases, closed-loop PID control is used. The aim is to achieve both the rapid response of an open-loop control system and the adjustment accuracy of a closed-loop control system. The test bench adjustment system involved in this patent has a bleed bypass path, where the air bypasses the engine. This is intended to quickly stabilize the engine's intake conditions and improve the speed of intake condition response.

[0030] Test bench control strategy: The air source supplies medium-pressure air downstream. The test bench provides downstream airflow (1.5 times the maximum flow required by the engine) through an opening regulating valve. The air temperature is ambient. After passing through an electric heater or refrigeration system, the incoming air temperature is adjusted from ambient to 15°C, which is the standard ambient air temperature. At the same time, the test bench control system dynamically maintains the engine inlet conditions at the standard atmospheric environment, i.e., a total intake pressure of 103.125 kPa and an intake temperature of 15°C, by changing the opening value of the engine intake path regulating valve (main path) and the exhaust bypass valve (bypass) (main path valve + bypass valve = 100%). Excess air is discharged into the atmosphere through the bypass.

[0031] The speed-compensation control strategy is used when the engine is in the starting phase. During the test run, the air supply is based on the relationship between engine speed and flow rate. Since the bypass air does not pass through the engine, it can be directly discharged into the atmosphere, avoiding the large inertia of the main circuit adjustment, solving the problem of slow intake adjustment of the matched engine, and ensuring the stability of the intake environment of the engine under various operating conditions of the calibrated reference thrust.

[0032] Stability is achieved when the engine is at the end of the starting phase. Once starting is complete, a closed-loop control strategy is implemented. During the test run, the opening of the regulating valve can be changed based on the engine intake pressure using the pressure deviation, thereby ensuring that the target pressure is consistent with the set pressure and performing closed-loop control.

[0033] The following is a further refinement of the above steps: Air cooling control method: The air cooling system consists of a wave machine 401, a fourth switch valve 402, and a fifth switch valve 403. Specifically, by opening the fourth switch valve 402, air from the medium-pressure air tank enters the wave machine 401 through the main air intake. By opening the fifth switch valve 403, the air outlet of the wave machine 401 is connected to the main air intake system, and air enters the wave machine 401. The output temperature range of the wave machine 401 is controlled to be -80℃ to 0℃. Air heating system: The air heating system consists of a second switching valve 301, an electric heater 302, and a third switching valve 303. Specifically, by opening the second switching valve 301, air from the medium-pressure air tank enters the electric heater 302 through the main air intake path. By opening the third switching valve 303, the air outlet of the electric heater 302 is connected to the main air intake system. The output temperature range of the air electric heater 302 is 0℃~180℃. The following is the overall process for pressure adjustment: 1. Engine start-up phase control: The test bench sets a speed threshold. When the engine speed is less than the set threshold (the threshold can be changed according to the engine model), the speed compensation control strategy is applied. When the engine speed is greater than the set threshold, it is judged to be in a steady-state operation state, and closed-loop control is switched.

[0034] Speed ​​compensation control strategy: Determine if the engine is in the starting phase, and look up the pressure at a specified speed n and the opening value of the main circuit 501 regulating valve. By calculating the engine intake pressure, and based on the intake pipe pressure and engine speed, dynamically adjust the main circuit second pressure regulating valve 501 to different openings. The opening of the secondary circuit third pressure regulating valve 601 follows the changes in the main circuit valves. The relationship is that the main circuit valve + bypass valve is associated with 100%. The lookup table obtained from the fluid flow results is shown in Table 1 below. Table 1 Query List Second: If the engine is determined to be in a steady-state operation, then the PID closed-loop control strategy is entered until the test ends.

[0035] The principle of a PID controller is that once an error (target value minus actual value) occurs, the PID controller needs to operate by providing a control quantity u(t). The control quantity and the error are related through three mathematical methods: proportional, integral, and differential coefficients, forming a PID control algorithm. By combining these three algorithms, the deviation of the controlled object is effectively corrected, thereby enabling it to reach a stable state.

[0036] In the formula: K p Proportional gain is a proportional response control system that reacts proportionally to the deviation signal. Once a deviation occurs, control is immediately activated to reduce the deviation.

[0037] Tt: Integral time, representing error accumulation, used to eliminate steady-state error and improve the system's error rate.

[0038] Td: Differential time, which can detect the trend of the deviation signal and introduce an effective early signal into the system before the value of the deviation signal becomes too large, thereby speeding up the system's response.

[0039] u(t): The output signal of the PID controller, i.e., the control quantity.

[0040] e(t): The difference between the given target value and the actual value.

[0041] Here, assuming the sampling interval is T, the deviation at the k-th time T is: e （k） =i （k） -o （k） The integral part is expressed in the form of summation, that is... e （k） +e （k+1） +e （k+2） +… The differential element is expressed in terms of slope, that is: (e) （k） -e （k+1） ) / T Discretization formula for PID algorithm: Incremental PID represents each PID correction, which can be obtained from the above expression: Therefore, the incremental PID is: The extraction error coefficients are: 3. Maintain the total pressure Pt at the engine intake port at the standard atmospheric pressure value. The control objects are the opening of the main line 501 valve and the bypass 601 valve, and the feedback pressure Pt value. Since the main line valve + bypass valve (as an associated valve) = 100%, the control quantity is given to the main line valve, and the bypass valve can be calculated.

[0042] In summary, this invention ensures the accuracy of engine inlet pressure through the coordinated operation of the main and secondary regulating valves. Specifically, the proposed speed compensation control and PID closed-loop composite control effectively address the issue of rapid engine response to compensated inlet flow and pressure at different stages. Furthermore, by utilizing the bypass regulating valve's decoupling from the engine (as it bypasses the engine), the pressure regulation time is reduced, and the speed and accuracy of pressure regulation are improved simultaneously to a certain extent. Moreover, the proposed control method employs both speed compensation interpolation-based closed-loop control and PID-based closed-loop control to simultaneously control the main and secondary regulating valves in real time, ensuring engine stability and rapid flow response. The lookup-table linear closed-loop control adjusts the opening of the main and bypass regulating valves, ensuring engine stability and preventing instability caused by abnormal engine speed regulation. When the error is small, this regulating valve is used to correct the pressure, ensuring accuracy.

[0043] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0044] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical functional division. In actual implementation, there may be other division methods, such as multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored.

[0045] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0046] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A continuous high altitude test stand, characterized in that, include: Medium-pressure gas source system: including medium-pressure gas tank and first switching valve, wherein the medium-pressure gas tank is connected to the main air intake pipeline through the switching valve; Main intake pipe: includes a first pressure regulating valve, a second pressure regulating valve and a first pressure rake, wherein the first pressure regulating valve is located between the main intake pipe and the medium-pressure air source system, the first pressure rake is located between the first pressure regulating valve and the second pressure regulating valve, and the main intake pipe is connected to the engine intake passage through the second pressure regulating valve. Engine intake passage: includes a second pressure rake and an intake pipe. The second pressure rake is located on the intake pipe and is used to test the pressure of the intake pipe. The output end of the intake pipe is connected to the engine. Exhaust bypass: Connected to the main intake pipe and located between the first pressure regulating valve and the second pressure regulating valve, it does not pass through the engine. The exhaust bypass is equipped with a third pressure regulating valve and a third pressure rake in sequence. The third pressure rake is used to test the air pressure after being regulated by the third pressure regulating valve.

2. A continuous tube altitude test stand according to claim 1, characterized in that It also includes air heating systems and air cooling systems, among which: The air heating system includes a second switching valve, an electric heater, and a third switching valve. The electric heater is connected to the main air intake pipe through the first and third switching valves, and the connection points of the second and third switching valves to the main air intake pipe are both located between the first and second pressure regulating valves. The air cooling system includes a fourth switching valve, an air wave generator, and a fifth switching valve. The air wave generator is connected to the main air intake pipe through the fourth and fifth switching valves. The connection between the fourth switching valve and the main air intake pipe is located between the first switching valve and the medium-pressure air source system. The connection between the fifth switching valve and the main air intake pipe is located between the first pressure regulating valve and the second pressure regulating valve.

3. The continuous pipe altitude test stand of claim 1, wherein, It also includes a first air filter, which is located between the first switch valve and the medium-pressure air source system, specifically at the outlet of the medium-pressure air tank.

4. The continuous high altitude test stand of claim 1 wherein, It also includes a second air filter, which is located between the exhaust bypass and the second pressure regulating valve, specifically at the air inlet of the intake pipe. The gas that has been processed by the main pipeline is filtered by the second air filter before being input into the engine intake pipe.

5. A continuous tube altitude test stand according to claim 2, wherein It also includes a first temperature rake and a second temperature rake, wherein the first temperature rake is located between the first pressure regulating valve and the second pressure regulating valve, and the second temperature rake is located on the air intake pipe.

6. A continuous tube altitude test stand according to claim 1, characterized in that The third pressure regulating valve and the second pressure regulating valve are equal-diameter, fast-reading opening valves.

7. A standard atmospheric environment simulation control method characterized by, The application of the tubular high-altitude test stand as described in claim 5 includes the following steps: When the first switch valve is opened, the air in the medium-pressure air tank enters the main air intake pipe, and the opening of the first pressure regulating valve is controlled so that the air pressure measured by the first pressure rake is more than 3 times the simulated air intake pressure of 103.23 kPa. By adjusting the outlet temperatures of the air cooling system and the air heating system to ensure that the temperature measured by the first temperature rake remains within 15℃±1.5℃ after mixing; The engine test bench sets a speed threshold. When the engine speed is less than the set threshold, the speed compensation control strategy controls the opening of the second and third pressure regulating valves to maintain the temperature measured by the second temperature rake at 15℃ and the second pressure rake at 101kPa, thereby ensuring that the engine is always in a standard environment. If the engine speed exceeds the set threshold, it is determined to be in a steady-state operation, and the PID closed-loop control is switched.

8. The standard atmospheric environment simulation control method according to claim 7, wherein, The specific process of control based on the speed compensation control strategy is as follows: To determine if the engine is in the starting phase, a lookup list of pressure at a specified speed n and the opening value of the main second pressure regulating valve is used. Then, by calculating the engine intake pressure value, and based on the intake pipe pressure value and the engine speed, the main second pressure regulating valve is dynamically adjusted to different opening degrees. The opening degree of the secondary third pressure regulating valve follows the change of the main valve, satisfying the condition that the opening ratio of the second pressure regulating valve + the opening ratio of the third pressure regulating valve = 100%.

9. The standard atmospheric environment simulation control method according to claim 7, wherein, The closed-loop control process is as follows: S1: Input the target and actual values; S2: Initialize PID parameters; S3: Calculate the third error coefficient and the target error value; S4: Determine if the error value is greater than the acceptable error range. If so, the control quantity is zero; otherwise, start PID calculation and provide the control quantity.

10. The standard atmospheric environment simulation control method according to claim 7, wherein, The specific process for ensuring that the temperature measured by the first temperature rake is maintained within 15℃±1.5℃ is as follows: When the temperature is above 15℃±1.5℃, the temperature is lowered by air cooling control method. The air cooling control method is as follows: by opening the fourth switch valve, the air in the medium pressure gas tank enters the air wave machine through the main air intake, and then the fifth switch valve is opened to connect the air outlet of the air wave machine to the main air intake system, so that air enters the air wave machine. When the temperature is below 15℃±1.5℃, the temperature is raised by air heating control method. Specifically, the air heating control method is as follows: by opening the second switch valve, air from the medium-pressure gas tank enters the electric heater through the main air intake, and by opening the third switch valve, the air outlet of the electric heater is connected to the main air intake system.

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