Automobile environment wind tunnel sunlight simulation safe operation system and method

Abstract

The application relates to the technical field of wind tunnel safe operation, and discloses a sunlight simulation safe operation system and method for an automobile environment wind tunnel, which comprises a control system, a temperature control system, a fresh air and humidity control system, a sunlight simulation device arranged in the wind tunnel, a main fan, a nozzle and a collecting port, a main airflow is formed between the nozzle and the collecting port, the sunlight simulation device is located above the main airflow, the nozzle is provided with an idling speed damper, a bypass air duct is arranged above the nozzle, a bypass damper is arranged in the bypass air duct, a bypass airflow is formed between the bypass air duct and the collecting port, and the sunlight simulation device is located in the bypass airflow, so that the problem that the preparation stage is long and the wind tunnel test efficiency is low when the low-temperature working condition of the existing wind tunnel is changed into a high-temperature working condition is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind tunnel safe operation, and particularly relates to a sunlight simulation safe operation system and method for an automobile environment wind tunnel. BACKGROUND

[0002] An automobile environment wind tunnel is a very important laboratory in automobile research and development. The wind tunnel can simulate real external climate environment. The temperature can be simulated to be -40-60 DEG C, the humidity can be simulated to be 5-95% relative humidity, the wind speed can be simulated to be 0-200 km / h, and the rain and snow simulation, sunlight simulation, etc. can be performed to perform extreme environment test on the automobile in the wind tunnel, such as high temperature heat balance / heat damage test, air conditioning cooling / heating test, low temperature cold start test, rain and snow test, etc. At the same time, the rotating drum arranged on the ground of the wind tunnel can make the automobile in the wind tunnel perform road driving state simulation and ensure that the resistance of the automobile driving on the rotating drum is consistent with the resistance of the automobile driving on the real road.

[0003] The sunlight simulation equipment is a very important system in the wind tunnel, which is installed above the wind tunnel chamber. The accurate simulation of the sunlight intensity, spectral band, uniformity and real-time in nature is an important environmental parameter necessary for high temperature and normal temperature test. The sunlight simulation complete equipment is expensive, generally about 4 million yuan. The number of lamp groups of a set of sunlight simulation equipment is 20-40, and the lamp tube in each lamp group is a consumable material, the service life is usually 2000 hours, and the price of a lamp tube is about 3000 yuan. Once damaged, it needs to be replaced immediately to ensure the uniformity and intensity of the light when the wind tunnel performs sunlight simulation test. The working environment of the sunlight simulation equipment is poor. The temperature in the wind tunnel is -40-60 DEG C, the humidity is 5-95%, and the service temperature of the sunlight simulation equipment after being turned on is usually above 25 DEG C. When the test condition in the wind tunnel changes from low temperature to high temperature, the surface of the sunlight simulation lamp group glass lamp shade is easy to condense water. When the light is turned on in the state of condensation of water, the sunlight simulation lamp group and the glass lamp shade are easy to burst, which not only seriously affects the service life of the equipment, but also has certain safety risk.

[0004] Currently, to avoid glass shattering accidents during the transition from low to high temperatures in solar simulation equipment, the safe practice is to keep the solar simulation off throughout the transition and to avoid humidification or humidity control during the heating process. For example, when changing a wind tunnel from -20℃ to 40℃ with 50% relative humidity, only heating is performed during the wind tunnel preparation phase, raising the internal temperature from -20℃ to 40℃. Humidification is not performed during this process. Often, after the mainstream air temperature inside the wind tunnel reaches 40℃, it is necessary to wait for more than an hour to observe whether condensation has formed on the surface of the solar simulation glass lamp cover. Only after confirming that there is no condensation on the glass lamp cover can the solar simulation equipment be pre-activated. The purpose of pre-activating the solar simulation is to allow the lamp assembly to heat up; it is usually turned off after 5 minutes. Finally, humidification is started through the new air humidity control system to bring the relative humidity inside the wind tunnel to the test setting of 50%. This entire preparation phase wastes 2 hours, significantly reducing the efficiency of the wind tunnel test. Summary of the Invention

[0005] The present invention aims to provide a safe operation system and method for automotive environmental wind tunnel sunlight simulation, in order to solve the problem that the preparation stage is time-consuming and the wind tunnel test efficiency is low when the wind tunnel is switched from low temperature to high temperature.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a safe operation system for automotive environmental wind tunnel sunlight simulation, comprising a control system, a temperature control system, a fresh air humidity control system, and a sunlight simulation device, a main fan, a nozzle, and a collection port installed inside the wind tunnel. A main airflow is formed between the nozzle and the collection port. The sunlight simulation device is located above the main airflow. The nozzle is equipped with an idle speed damper. A bypass air duct is provided above the nozzle. A bypass damper is provided inside the bypass air duct. A bypass airflow is formed between the bypass air duct and the collection port. The sunlight simulation device is located in the bypass airflow.

[0007] The beneficial effects of this scheme are as follows: By innovatively proposing to simultaneously open the main airflow and the bypass airflow during the preparation stage of the wind tunnel transition from low temperature to high temperature, the bypass airflow is used to blow the sunlight simulation equipment to rapidly raise its temperature while normal preparation and debugging are carried out, thereby greatly shortening the preparation time and achieving the goal of improving the wind tunnel operating efficiency.

[0008] Preferably, the wind tunnel is equipped with an air duct, and a wind tunnel temperature sensor and a wind tunnel humidity sensor are installed inside the air duct. The wind tunnel temperature sensor and the wind tunnel humidity sensor acquire the actual values ​​of the wind tunnel temperature and the wind tunnel humidity, respectively. A sunlight simulation temperature sensor is installed on the sunlight simulation equipment, and a bypass airflow temperature sensor and a bypass airflow humidity sensor are installed in the bypass airflow. The sunlight simulation temperature sensor acquires the surface temperature of the sunlight simulation equipment, and the bypass airflow temperature sensor and the bypass airflow humidity sensor acquire the actual values ​​of the bypass airflow temperature and the bypass airflow humidity, respectively. The wind tunnel temperature sensor, the wind tunnel humidity sensor, the sunlight simulation temperature sensor, the bypass airflow temperature sensor, and the bypass airflow humidity sensor are all connected to the control system.

[0009] Preferably, it also includes a method for safe operation of automotive environmental wind tunnel sunlight simulation, which determines whether the wind tunnel is in preparation mode based on the above-mentioned automotive environmental wind tunnel sunlight simulation safe operation system.

[0010] If the wind tunnel is in preparation mode, determine whether the preparation mode is a low temperature to high temperature transition state;

[0011] If the wind tunnel is transitioning from a low temperature to a high temperature state, and the test requires the sunlight simulation equipment to be turned on, then control the bypass damper and idle speed damper to open, and the bypass airflow to blow the sunlight simulation equipment.

[0012] During the bypass airflow purging process, it is further determined whether the surface temperature of the solar simulation equipment is greater than the wind tunnel test set dew point temperature under the wind tunnel test set conditions;

[0013] If the surface temperature of the sunlight simulation equipment is higher than the dew point temperature set for the wind tunnel test, then the sunlight simulation equipment will be turned on.

[0014] The beneficial effects of this solution are as follows: While conducting normal preparation and commissioning, the bypass airflow is used to purge the sunlight simulation equipment, rapidly raising its temperature and significantly shortening preparation time, thereby improving wind tunnel operating efficiency. Simultaneously, the timing of starting the sunlight simulation equipment is further assessed to ensure timely activation while maintaining safety, further reducing the preparation time. Furthermore, in the actual operation of the automotive environmental wind tunnel, the main fan operates at a relatively high speed during the testing phase. However, during the preparation phase, when the environmental wind tunnel is undergoing temperature and humidity control, with the vehicle and drum not started, and the main fan, sunlight simulation system, temperature control system, and fresh air humidity control system all operating, the maximum wind speed of the main airflow after the main fan starts is below 30 kph. Therefore, even with the bypass airflow activated during the preparation phase, although the main fan's operating power increases, its total power remains low, ensuring the safety of the main fan's operation.

[0015] Preferably, the specific method for determining whether the preparation mode is transitioning from a low-temperature to a high-temperature state is as follows:

[0016] The actual wind tunnel temperature is determined to be less than the first threshold, and the wind tunnel temperature setpoint is greater than the actual wind tunnel temperature.

[0017] At the same time, it was determined that the wind tunnel humidity setpoint was greater than the second threshold.

[0018] Preferably, the specific method for determining whether a wind tunnel is in preparation mode is as follows:

[0019] Ensure that the main fan, temperature control system, and fresh air humidity control system are all in operation.

[0020] Preferably, after the sunlight simulation equipment is turned on, the idle speed damper is closed to prepare for the wind tunnel test phase after the preparation phase.

[0021] Preferably, the wind tunnel preparation stage also includes a heating and humidification control strategy, specifically:

[0022] Determine the deviation value of the simulated solar humidity based on the set value of the simulated solar humidity and the actual value of the simulated solar humidity;

[0023] The wind tunnel humidity setpoint was determined based on the humidity deviation value simulated by sunlight.

[0024] The opening degree of the humidity spray gun in the new air control system is determined based on the wind tunnel humidity setpoint and the actual wind tunnel humidity value.

[0025] The beneficial effects of this solution are as follows: The heating and humidification control strategy includes an outer loop control loop and an inner loop control loop. The inner loop control loop, based on the actual humidity value inside the wind tunnel and the set humidity value inside the wind tunnel, achieves coarse adjustment of the opening of the humidity spray gun in the new air humidification system. The outer loop control loop, based on the actual and set humidity value of the bypass airflow in the environment where the sunlight simulation equipment is located, achieves coarse adjustment of the opening of the humidity spray gun in the new air humidification system. This allows for rapid and precise adjustment of the opening of the humidity spray gun in the new air humidification system, enabling simultaneous humidification of the wind tunnel during the preparation phase and preventing condensation and cracking on the surface of the sunlight simulation equipment by controlling the dew point temperature of the bypass airflow to always be lower than the actual surface temperature of the sunlight simulation.

[0026] Preferably, when determining the opening degree of the humidity spray gun, the method further includes:

[0027] The wind tunnel humidity deviation value is determined based on the wind tunnel humidity setpoint and the actual wind tunnel humidity value.

[0028] The opening of the humidity spray gun is calculated based on the humidity deviation value in the wind tunnel.

[0029] Preferably, the specific method for determining the simulated humidity setting value is as follows:

[0030] Determine the dew point temperature of the bypass airflow based on the actual temperature and humidity values ​​of the bypass airflow.

[0031] The humidity setpoint for sunlight simulation is calculated based on the dew point temperature of the bypass airflow and the surface temperature of the sunlight simulation device.

[0032] Preferably, the formula for calculating the simulated humidity setpoint is:

[0033]

[0034] In the formula: t set dewpoint t is the dew point temperature of the bypass airflow. sun This represents the actual temperature of the bypass airflow. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the wind tunnel structure in the front view direction in Embodiment 1 of the present invention;

[0036] Figure 2 This is a flowchart illustrating the control method in Embodiment 1 of the present invention;

[0037] Figure 3 This is a schematic diagram of the wind tunnel structure in the front view direction in Embodiment 2 of the present invention;

[0038] Figure 4 This is a flowchart illustrating the control strategy in Embodiment 2 of the present invention. Detailed Implementation

[0039] The following detailed description illustrates the specific implementation method:

[0040] The reference numerals in the accompanying drawings include: first corner 101, second corner 102, third corner 103, fourth corner 104, nozzle 105, sump chamber 106, insulation plate 107, collection port 108, tracked drum pit cover 109, drum 110, drum pit 111, main fan 112, main heat exchanger 113, bypass damper 114, bypass duct 115, bypass airflow 116, connecting mechanism 117, sunlight simulation equipment 118, bypass airflow temperature sensor 119, bypass airflow humidity sensor 120, sunlight simulation temperature sensor 121, idling damper 122, main airflow 123, wind tunnel temperature sensor 124, and wind tunnel humidity sensor 125.

[0041] Example 1

[0042] Example 1 is basically as shown in the appendix. Figures 1-2 As shown, Figure 1The illustrated automotive environmental wind tunnel sunlight simulation safety operation system includes a wind tunnel and a temperature control system, a fresh air humidity control system, and a control system connected to the wind tunnel. The temperature control system enables precise control of the temperature inside the wind tunnel, the fresh air humidity control system enables precise control of the humidity inside the wind tunnel, and the control system, i.e., the intelligent control platform, enables automated control of the wind tunnel test environment. These are all existing technologies in automotive environmental wind tunnels and will not be elaborated upon here.

[0043] The wind tunnel is equipped with a first bend 101, a second bend 102, a third bend 103, and a fourth bend 104. The first bend 101, the second bend 102, the third bend 103, and the fourth bend 104 are the airflow circulation ducts inside the wind tunnel. The first bend 101 is the passage for the car to enter and exit the wind tunnel. A main fan 112 is installed between the second bend 102 and the third bend 103. The main fan 112 provides power for the car environmental wind tunnel test to accelerate the air inside the wind tunnel to form the wind speed required for the test. In this embodiment, the main fan 112 works to make the air circulate counterclockwise along the air duct. A testing chamber 106 is located between the first corner 101 and the fourth corner 104. The testing chamber 106 serves as the vehicle's testing lab. The side walls of the testing chamber 106 are equipped with insulated panels 107. The bottom of the testing chamber 106 includes a tracked drum pit cover 109, a drum 110, and a drum pit 111. The insulated panels 107 ensure that the test temperature is controlled within the set temperature. The drum 110 simulates vehicle road dynamics to further ensure the accuracy of test parameters. A sunlight simulation device 118 is located directly above the drum 110. A connecting mechanism 117 connects the sunlight simulation device 118 to the top of the testing chamber 106, allowing the connected sunlight simulation device 118 to move vertically within the testing chamber 106. A nozzle 105 is installed at one end of the air duct at the fourth corner 104 extending into the sump chamber 106, and a collection port 108 is installed at one end of the air duct at the first corner 101 extending into the sump chamber 106. A main airflow 123 is formed between the nozzle 105 and the collection port 108. During the test, the car needs to be placed in the main airflow 123. A main heat exchanger 113 is installed at the third corner 103. The main heat exchanger 113 is an important device in the temperature control system. When the main fan 112 is working, the air continuously flows through the main heat exchanger 113 for heat exchange and cooling. After reaching the set temperature required for the test, the air is guided through the third corner 103 and the fourth corner 104 and sprayed out from the nozzle 105 into the sump chamber 106 to blow air onto the test car. Then, the air is guided through the collection port 108, the first corner 101, and the second corner 102 to the rear end of the main fan 112, thus completing one cycle.

[0044] like Figure 1As shown, the nozzle 105 is equipped with an idle speed damper 122, which is an electric roller shutter door. The nozzle 105 can be closed and opened through the idle speed damper 122. When the test needs to be set to an idle state or a stationary state (the idle state is the test state where the car engine is running but the car is stationary), since there is no wind blowing in front of the car in the real environment, the wind tunnel test also needs to pull down and close the idle speed damper 122 to prevent the nozzle 105 from blowing air onto the car, ensuring that the relative wind speed of the environment in which the car is located is 0 kph under the idle state or stationary simulation test. However, precise control of temperature and humidity during wind tunnel testing requires fresh air circulation. Therefore, a bypass duct 115 is connected at the fourth corner 104. The bypass duct 115 extends into the interior of the chamber 106, located above the nozzle 105. A bypass damper 114 is installed inside the bypass duct 115. Opening the bypass damper 114 allows air circulation within the wind tunnel to occur even with the idle damper 122 closed. This ensures that the airflow continues to exchange heat and maintain temperature and humidity effectively with the main heat exchanger 113 and the fresh air humidity control system, driven by the main fan 112. Simultaneously, a bypass airflow 116 is formed between the upper bypass duct 115 and the collection port 108, within which the sunlight simulation device 118 is located.

[0045] When a wind tunnel finishes one test and begins the next, it undergoes a preparation phase. During this phase, relevant equipment in various systems within the wind tunnel begins operation to adjust the internal temperature and humidity to the values ​​required for the next test. Solar simulation is the most common test environment in wind tunnels. If the upcoming test requires the activation of the solar simulation device 118, and the preparation phase involves transitioning the wind tunnel from a low-temperature to a high-temperature state, condensation will form on the glass covers and lamps of the solar simulation device 118 during the temperature rise process. If the lights are turned on at this time, the internal temperature of the lamps will rise rapidly, potentially causing the glass to shatter. Existing methods to prevent the solar simulation device 118 from shattering prolong the preparation phase, increase wind tunnel operating costs, and reduce wind tunnel test efficiency.

[0046] Therefore, as Figure 2As shown, this embodiment also provides a safe operation method for automotive environmental wind tunnel sunlight simulation. Based on the above-mentioned wind tunnel internal structure, it innovatively proposes that during the preparation stage of the wind tunnel from low temperature to high temperature, the circulating airflow inside the wind tunnel is divided into two paths to enter the wind tunnel. The main airflow 123 ensures the normal preparation of the vehicle's temperature and humidity, while the bypass airflow 116 enters the sump chamber 106 from the upper part and blows through the sunlight simulation equipment 118, effectively making the sunlight simulation equipment 118 heat up rapidly and preventing the glass lamp cover from cracking due to condensation. Ultimately, while preventing the sunlight simulation equipment 118 from cracking, the time required for the wind tunnel preparation stage can be reduced, and the wind tunnel operation efficiency can be improved.

[0047] The control system monitors the wind tunnel's current mode and parameters such as wind speed, temperature, and humidity inside the wind tunnel in real time.

[0048] like Figure 2 As shown, firstly, the control system determines whether the wind tunnel is in preparation mode. If it determines that the wind tunnel is not in preparation mode, it indicates that the wind tunnel is currently in test mode or shutdown mode. In shutdown mode, the sunlight simulation equipment 118 is stopped, so there is no need to consider the risk of explosion, and therefore there is no need to consider opening or closing the bypass damper 114. If the wind tunnel is in test mode, the bypass damper 114 is not allowed to be opened to prevent the main fan 112 from exceeding its power and causing a safety accident. In test mode (i.e., in the automotive environment wind tunnel, under normal automotive test conditions), the wind speed of the main airflow 123 will generally exceed 30 kph, and can reach a maximum of 200 kph. If the bypass damper 114 is kept open at this time, the main fan 112 will exceed its power limit in order to ensure the test set wind speed, which may lead to a safety accident. Therefore, the bypass damper 114 needs to be closed. If the control system determines that the wind tunnel is in preparation mode, it continues to the next step of judgment.

[0049] After confirming that the wind tunnel is in preparation mode, it is further determined whether temperature and humidity control is being implemented inside the wind tunnel. The specific method for judgment is as follows: check whether the main fan 112, temperature control system, and fresh air humidity control system are operating. If all these systems and equipment are operating, it indicates that the wind tunnel is in preparation mode and temperature and humidity control is in progress. If some systems and equipment are not operating, it means that temperature and humidity control is not required inside the wind tunnel in preparation mode; that is, the conditions before and after the test are not significantly different, the preparation mode is about to end, there is no heating or humidification operation, the sunlight simulation equipment 118 does not pose a risk of explosion, and therefore there is no need to initiate the next step of safety operation control to improve efficiency.

[0050] Once it's confirmed that the wind tunnel is in preparation mode and undergoing temperature and humidity control, further determination is needed to determine if the wind tunnel is transitioning from a low-temperature to a high-temperature state. The criteria for this determination are: whether the actual wind tunnel temperature is less than a first threshold, whether the wind tunnel temperature setpoint is greater than the actual wind tunnel temperature, and whether the wind tunnel humidity setpoint is greater than a second threshold. If all three conditions are met—actual wind tunnel temperature < first threshold, wind tunnel temperature setpoint > actual wind tunnel temperature + Δt1, and wind tunnel humidity setpoint > second threshold—it can be determined that the wind tunnel is transitioning from a low-temperature to a high-temperature state and is undergoing humidity control. Additionally, if... Figure 1 As shown, the actual wind tunnel temperature is obtained by a wind tunnel temperature sensor installed at the third corner. The first threshold is customized according to the wind tunnel test temperature control conditions. The first threshold represents the temperature of the wind tunnel in a low-temperature environment. In this embodiment, the first threshold is 15℃, that is, if the actual temperature inside the wind tunnel is less than 15℃, it indicates that the wind tunnel is currently in a low-temperature environment. If the wind tunnel temperature setpoint is greater than the actual wind tunnel temperature, it indicates that the current preparation stage is in a heating state. Δt1 is the temperature difference margin between the wind tunnel temperature setpoint and the actual wind tunnel temperature. If the difference between the wind tunnel temperature setpoint and the actual wind tunnel temperature is too small, and the heating process in the preparation stage is relatively fast, the control of safe operation of the sunlight simulation is not very meaningful. Therefore, Δt1 is set to increase the difference between the wind tunnel temperature setpoint and the actual wind tunnel temperature when making the judgment. The setting of Δt1 can be customized according to the heating efficiency of the wind tunnel in the automotive environment. If the wind tunnel humidity setpoint is determined to be greater than the second threshold, it means that the wind tunnel currently has a set relative humidity, and humidity control is still required. This means that the wind tunnel will be subjected to high temperature and high humidity test conditions in the future, and there is a risk that the sunlight simulation equipment will explode after the lights are turned on. The next step of safe operation needs to be performed. The second threshold can be determined based on the actual environment of the wind tunnel and is not limited in this embodiment.

[0051] Meanwhile, to further ensure the accuracy of the safe operation control of the sunlight simulation, after confirming that the wind tunnel is in a humidity-controlled state transitioning from low to high temperature, it is also necessary to determine whether the environmental wind tunnel has executed the idle mode command and the command to activate the sunlight simulation equipment 118. If the control system issues the idle mode command, it needs to control the idle damper 122 to close and the bypass damper 114 to open, so that the wind tunnel enters the normal idle mode; otherwise, it continues to the next step of judgment. Determining whether the control system has activated the sunlight simulation equipment 118 is equivalent to determining whether to click on the pre-selected sunlight simulation. If not, it means that although the next step of the wind tunnel is a high temperature and high humidity test, the test conditions do not require the activation of the sunlight simulation equipment 118, and therefore it is not necessary to activate the bypass damper 114 to perform the safety control method of rapidly heating the sunlight simulation equipment 118; if so, it means that the subsequent test environment requires the activation of the sunlight simulation equipment 118, and the control system enters the next safety control process.

[0052] Once the wind tunnel is determined to be in a humidity-controlled preparation mode transitioning from low to high temperature, and the sunlight simulation equipment 118 requires lighting during the testing phase, the control system opens the bypass damper 114 and the idle damper 122. The bypass airflow 116 enters the sump chamber 106 via the bypass duct, purging the sunlight simulation equipment 118. In this temperature-raising preparation mode, all airflow is high-temperature. Therefore, under the continuous purging action of the high-temperature bypass airflow 116, the lamp assembly and glass cover of the sunlight simulation equipment 118 can be rapidly heated, preventing condensation from adhering to the glass surface and the risk of cracking after lighting is turned on. The rapid heating of the sunlight simulation equipment 118 significantly shortens the anti-condensation waiting time during the preparation phase, thereby reducing the time required for the wind tunnel preparation phase and improving wind tunnel operating efficiency.

[0053] Furthermore, to further ensure the safe operation of the sunlight simulation device, this control method also further controls the lighting time of the sunlight simulation equipment 118. Specifically, as follows... Figure 2 As shown, it is determined whether the surface temperature of the sunlight simulation device 118 is greater than the wind tunnel temperature setting value, and whether the surface temperature of the sunlight simulation device 118 is greater than the dew point temperature corresponding to the wind tunnel humidity setting value (i.e., the wind tunnel test dew point temperature). If the surface temperature of the sunlight simulation device 118 is greater than both the wind tunnel temperature setting value and the wind tunnel humidity setting value corresponding to the dew point temperature, it indicates that the temperature of the sunlight simulation device 118 is high enough and higher than the dew point temperature of the wind tunnel under test conditions. This ensures that condensation will not occur on the surface of the sunlight simulation device 118, and at this time, the sunlight simulation device 118 can be turned on as needed to prepare for the test phase. Figure 1 As shown, the surface temperature of the sunlight simulation device is obtained by a sunlight simulation temperature sensor 121 installed on the surface of the sunlight simulation device 118. Furthermore, when judging the surface temperature of the sunlight simulation device against the dew point temperature corresponding to the wind tunnel humidity setting, a margin temperature difference Δt2 is also provided; that is, the judgment criterion is: sunlight simulation device surface temperature > wind tunnel humidity setting dew point temperature + Δt2. There will be a certain delay in the control process of the control system. The margin temperature difference Δt2 is set to compensate for the delay and further prevent condensation on the surface of the sunlight simulation device. In this embodiment, Δt2 is 5°C. Finally, when the surface temperature of the sunlight simulation device 118 rises to a level where the lights can be turned on, the bypass damper 114 is closed, allowing the airflow to circulate only the main airflow. The wind tunnel preparation stage is completed, and the experiment can begin.

[0054] This embodiment innovatively proposes to simultaneously activate both the main airflow 123 and the bypass airflow 116 during the preparation stage of the wind tunnel transition from low to high temperature. While normal preparation and debugging are being carried out, the bypass airflow 116 is used to purge the sunlight simulation equipment 118, causing it to heat up rapidly, thereby greatly shortening the preparation time and improving the operating efficiency of the wind tunnel. At the same time, the timing of activating the sunlight simulation equipment 118 is further judged and selected to ensure that the sunlight simulation equipment 118 is activated in a timely manner while ensuring safety, further shortening the time required for the preparation stage. In addition, during the actual operation of the automotive environmental wind tunnel, the main fan 112 operates at a relatively high speed during the test phase. However, during the preparation phase, the environmental wind tunnel is prepared for temperature and humidity control. The vehicle is not started, the drum 110 is not started, and the main fan 112, the sunlight simulation system, the temperature control system, and the fresh air humidity control system are all in operation. Even with the main fan 112 running, the maximum wind speed of the main airflow 123 is still below 30 kph. Therefore, even if the bypass airflow 116 is turned on during the preparation phase and the operating power of the main fan 112 increases, its total power remains low, ensuring the safety of the main fan 112's operation.

[0055] Example 2

[0056] like Figures 3-4 The automotive environmental wind tunnel sunlight simulation safety operation system and method shown differs from Embodiment 1 in that it also includes a heating and humidification control strategy. In Embodiment 1, although the sunlight simulation device 118 is purged and heated by the bypass airflow 116 during the preparation stage, which allows the sunlight simulation device 118 to heat up quickly and reduces the time required for the preparation stage, the wind tunnel remains in a stopped humidification state during the heating process of the sunlight simulation device 118 and until the heating process is completed, and the humidification process still requires a relatively long wait.

[0057] To reduce the humidification waiting time during the preparation phase and further improve the wind tunnel's operating efficiency, this embodiment proposes a heating and humidification control strategy. This strategy ensures safe operation of the solar simulation while initiating humidification during the heating phase of the solar simulation equipment 118. Humidification of the wind tunnel is achieved by spraying water vapor from humidity spray guns in the new air control and humidification system. Meanwhile, as... Figure 3 As shown, a bypass airflow temperature sensor 119 and a bypass airflow humidity sensor 120 are installed above the sump 106, both located within the bypass airflow 116. These sensors acquire real-time temperature and humidity values ​​of the bypass airflow 116, thus providing real-time information on the temperature and humidity of the environment surrounding the sunlight simulation device 118 located within the bypass airflow 116. Simultaneously, a wind tunnel humidity sensor 125 is installed at the third corner 103, acquiring real-time humidity values ​​from the wind tunnel.

[0058] like Figure 4As shown, the heating and humidification control strategy includes an outer loop control loop and an inner loop control loop. The inner loop control loop, based on the actual humidity value inside the wind tunnel and the set humidity value inside the wind tunnel, achieves coarse adjustment of the opening of the humidity spray gun in the new air humidification system. The outer loop control loop, based on the actual and set humidity values ​​of the bypass airflow 116 in the environment where the sunlight simulation device 118 is located, achieves coarse adjustment of the opening of the humidity spray gun in the new air humidification system. This allows for rapid and precise adjustment of the opening of the humidity spray gun in the new air humidification system, enabling simultaneous humidification of the wind tunnel during the preparation phase and preventing condensation and cracking on the surface of the sunlight simulation device 118 by controlling the dew point temperature of the bypass airflow to always be lower than the actual value of the sunlight simulation surface temperature.

[0059] Wherein: Φsun is the actual value of the simulated humidity of sunlight (i.e., the actual value of the humidity of the bypass airflow, obtained by the bypass airflow humidity sensor 120), Φsun set is the set value of the simulated humidity of sunlight (calculated based on the surface temperature of the simulated sunlight equipment and the dew point temperature of the bypass airflow), E1(S) is the deviation value (i.e., the difference) between Φsun set and Φsun, and PID1 is the PID calculation of the outer loop control loop; Φwind tunnel is the actual value of the humidity of the wind tunnel (obtained by the wind tunnel humidity sensor 125), Φwindtunnel set is the set value of the humidity of the wind tunnel (obtained by PID1 and dynamically adjusted), E2(S) is the deviation value between Φwind tunnel set and Φwind tunnel, and PID2 is the PID calculation of the inner loop control loop; u(s) is the opening degree of the humidity spray gun in the new air humidity control system, and the opening degree of the humidity spray gun controls the humidity of the main airflow 123 and the bypass airflow 116, G1(s) is the transfer function between Φwindtunnel and u(s), and G2(s) is the transfer function between Φwind tunnel and Φsun.

[0060] In the process of wind tunnel humidity control, the control process between the opening degree u(s) of the humidity spray gun and the actual value of the simulated humidity Φsun is a large-inertia, large-delay, and nonlinear control system, making it extremely difficult to control. However, by setting up an outer loop control loop combined with an inner loop control loop, the control response between the humidity spray gun opening degree u(s) and the actual wind tunnel humidity value Φwindtunnel is relatively fast, allowing for rapid control of the actual wind tunnel humidity value to the set humidity level, thus accelerating the response speed of the entire control system. Therefore, the design first uses the inner loop control loop to quickly and coarsely adjust the opening degree u(s) of the humidity spray gun. Then, based on this coarse adjustment, the outer loop control loop is used to finely adjust the opening degree u(s), and minor corrections are made to the humidity control in the simulated sunlight area after the coarse adjustment by the inner loop control loop, achieving the goal of rapid fine adjustment. The specific control process is as follows:

[0061] The deviation between the simulated sunlight humidity setpoint Φsun set and the actual simulated sunlight humidity value Φsun is calculated to obtain E1(S). This deviation is then processed by PID1 to obtain the wind tunnel humidity setpoint Φwind tunnel set. This constitutes the outer loop control, which enables precise control of the humidity in the simulated sunlight area. The actual wind tunnel humidity value Φwind tunnel and the opening degree u(s) of the humidity spray gun are related by a transfer function G1(s).

[0062] The deviation between the wind tunnel humidity setpoint Φwind tunnel set and the actual wind tunnel humidity value Φwind tunnel is calculated to obtain E2(S). This deviation is then corrected using PID2 to adjust the opening degree u(s) of the humidity spray gun. Real-time precise control of the humidity spray gun opening allows for precise control of the wind tunnel humidity; this is the inner loop control loop. The controlled object of the inner loop control loop (wind tunnel humidity) and the controlled object of the outer loop control loop (humidity in the sunlight simulation area) are related by a transfer function G2(s). The transfer functions G1(s) and G2(s) vary depending on the wind tunnel system and equipment conditions, and since these transfer functions are existing technologies, they will not be elaborated upon here.

[0063] Furthermore, in the aforementioned temperature and humidification control strategy, determining the setpoint Φsun set for the simulated sunlight humidity is crucial. Φsun set cannot be set too high, as this will cause condensation on the surface of the simulated sunlight device, while setting it too low will delay the humidification control time and reduce wind tunnel testing efficiency. Therefore, real-time calculation and determination of the simulated sunlight humidity setpoint Φsun set is particularly important. Based on Example 1, a simulated sunlight temperature sensor is installed on the surface of the simulated sunlight device. This sensor monitors the surface temperature of the simulated sunlight device in real time. Therefore, to ensure that condensation does not form on the surface of the simulated sunlight device, the bypass airflow dew point temperature (i.e., the real-time dew point temperature of the area where the simulated sunlight device is located), calculated from the bypass airflow temperature and humidity values, must be lower than the surface temperature of the simulated sunlight device. Further, considering a safety margin, the bypass airflow dew point temperature is set lower than the surface temperature of the simulated sunlight device plus a third threshold. In this embodiment, the third threshold is set to 5°C, i.e.:

[0064] t set dewpoint <t sun surface -5 (1)

[0065] In the formula: t sun surface For the surface temperature of the sunlight simulation device, t set dewpoint t is the dew point temperature of the bypass airflow. set dewpointThe bypass airflow dew point temperature is calculated from the actual bypass airflow temperature and the actual bypass airflow humidity.

[0066] The solar simulation humidity setpoint Φsun set is calculated from the actual bypass airflow temperature and the bypass airflow dew point temperature, using the following formula:

[0067]

[0068] In the formula: t set dewpoint t is the dew point temperature of the bypass airflow. sun This represents the actual temperature of the bypass airflow.

[0069] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for safe operation of a car environment wind tunnel under sunlight simulation, based on a car environment wind tunnel under sunlight simulation safe operation system, for determining whether the wind tunnel is in a ready mode; characterized in that: A safe operation system for simulating sunlight in an automotive environmental wind tunnel includes a control system, a temperature control system, a fresh air humidity control system, and a sunlight simulation device, a main fan, nozzles, and a collection port installed inside the wind tunnel. A main airflow is formed between the nozzles and the collection port. The sunlight simulation device is located above the main airflow. The nozzles are equipped with idle speed dampers. A bypass duct is located above the nozzles, and a bypass damper is installed within the bypass duct. A bypass airflow is formed between the bypass duct and the collection port. The sunlight simulation device is located within the bypass airflow. An air duct is provided inside the wind tunnel, and a wind tunnel temperature sensor and a wind tunnel humidity sensor are installed within the air duct. The wind tunnel temperature sensor... The wind tunnel temperature sensor and the wind tunnel humidity sensor acquire the actual values ​​of the wind tunnel temperature and humidity, respectively. The sunlight simulation equipment is equipped with a sunlight simulation temperature sensor, and the bypass airflow is equipped with a bypass airflow temperature sensor and a bypass airflow humidity sensor. The sunlight simulation temperature sensor acquires the surface temperature of the sunlight simulation equipment, and the bypass airflow temperature sensor and the bypass airflow humidity sensor acquire the actual values ​​of the bypass airflow temperature and the bypass airflow humidity, respectively. The wind tunnel temperature sensor, the wind tunnel humidity sensor, the sunlight simulation temperature sensor, the bypass airflow temperature sensor, and the bypass airflow humidity sensor are all connected to the control system. If the wind tunnel is in preparation mode, determine whether the preparation mode is a low temperature to high temperature transition state; If the wind tunnel is in a low-temperature to high-temperature state and the test requires the sunlight simulation equipment to be turned on, then control the bypass damper and idle damper to open, and the bypass airflow to blow the sunlight simulation equipment. During the bypass airflow purging process, it is further determined whether the surface temperature of the solar simulation equipment is greater than the wind tunnel test set dew point temperature under the wind tunnel test set conditions; If the surface temperature of the sunlight simulation equipment is higher than the dew point temperature set for the wind tunnel test, then the sunlight simulation equipment will be turned on. The wind tunnel preparation phase also includes heating and humidification control strategies, specifically: Determine the deviation value of the simulated solar humidity based on the set value of the simulated solar humidity and the actual value of the simulated solar humidity; The wind tunnel humidity setpoint was determined based on the humidity deviation value simulated by sunlight. The opening degree of the humidity spray gun in the new air control system is determined based on the wind tunnel humidity setpoint and the actual wind tunnel humidity value.

2. The safe operation method for automotive environmental wind tunnel sunlight simulation according to claim 1, characterized in that: The specific method to determine whether the preparation mode is transitioning from a low temperature to a high temperature state is as follows: The actual wind tunnel temperature is determined to be less than the first threshold, and the wind tunnel temperature setpoint is greater than the actual wind tunnel temperature. At the same time, it was determined that the wind tunnel humidity setpoint was greater than the second threshold.

3. The safe operation method for automotive environmental wind tunnel sunlight simulation according to claim 2, characterized in that: The specific method for determining whether a wind tunnel is in ready mode is as follows: Ensure that the main fan, temperature control system, and fresh air humidity control system are all in operation.

4. The safe operation method for automotive environmental wind tunnel sunlight simulation according to claim 3, characterized in that: After the sunlight simulation equipment is turned on, the idle speed damper is closed to prepare for the wind tunnel test phase after the preparation phase.

5. The safe operation method for automotive environmental wind tunnel sunlight simulation according to claim 4, characterized in that: Determining the opening of the humidity spray gun also includes: The wind tunnel humidity deviation value is determined based on the wind tunnel humidity setpoint and the actual wind tunnel humidity value. The opening of the humidity spray gun is calculated based on the humidity deviation value in the wind tunnel.

6. The safe operation method for automotive environmental wind tunnel sunlight simulation according to claim 5, characterized in that: The specific method for determining the simulated humidity setting for sunlight is as follows: Determine the dew point temperature of the bypass airflow based on the actual temperature and humidity values ​​of the bypass airflow. The humidity setpoint for sunlight simulation is calculated based on the dew point temperature of the bypass airflow and the surface temperature of the sunlight simulation device.

7. A method for safe operation of a vehicle environment wind tunnel under sunlight simulation according to claim 6, characterized in that: The formula for calculating the simulated humidity setpoint is: In the formula: t set dewpoint t is the dew point temperature of the bypass airflow. sun This represents the actual temperature of the bypass airflow.

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