Vehicle wind resistance coefficient testing system and method

Abstract

The invention relates to the technical field of vehicle monitoring, and discloses a vehicle drag coefficient test system. The air pressure sensor is used for collecting the air pressure at the test point; the air velocity sensor is used for collecting the velocity of air at the test point; the temperature sensor is used for collecting the air temperature at a test point, and the data analysis module is used for analyzing the air temperature of the test point according to the parameters of the air velocity sensor and the temperature sensor at the test point, the vehicle speed monitored by the GPS positioning module, the vehicle front projection area provided by the data acquisition module and the wind resistance borne by the vehicle at the corresponding vehicle speed. And the wind resistance coefficients of the vehicle in different air temperature environments are determined. According to the invention, when the wind resistance coefficient of the vehicle is tested, more test points are used, and each test point can be tested in different climatic environments, so that the wind resistance of the vehicle test tends to reality, and the wind resistance coefficient of the vehicle is ensured to be closer to the actual situation.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle monitoring, and in particular to a vehicle drag coefficient testing system and method. Background Art

[0002] Vehicle sliding resistance is composed of chassis resistance and wind resistance. Vehicle wind resistance and drag coefficient are usually measured using wind tunnel tests. However, wind tunnel tests often cannot better fit actual driving conditions.

[0003] The existing patent discloses a vehicle drag coefficient test method (CN115266015A), which includes: step S1, sliding the vehicle on the road to obtain the road sliding resistance coefficient and road resistance; step S2, placing the vehicle on a hub test bench, performing a hub test, and obtaining the hub chassis resistance coefficient and hub chassis resistance; step S3, obtaining the windward area of ​​the vehicle; step S4, using the road resistance and hub chassis resistance, under set conditions, converting the hub chassis resistance into a road chassis resistance related to both the hub chassis resistance coefficient and the road sliding resistance coefficient. In the technology disclosed in the patent, due to factors such as engine heating at different positions of the vehicle, the air density and air flow rate above the vehicle will not be the same. Therefore, when testing the vehicle drag coefficient, more test points are required to make the wind resistance of the vehicle test more realistic. In addition, the sensors at each test point will interfere with each other, thereby increasing the measurement error. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a vehicle drag coefficient testing system and method, which solves the problems in the above-mentioned background technology.

[0005] To solve the above technical problems, according to one aspect of the present invention, more specifically, a vehicle drag coefficient test system includes a data analysis module, a compensation optimization module, a GPS positioning module, a data acquisition module and a sensor; The sensors include an air pressure sensor, an air flow rate sensor and a temperature sensor: the air pressure sensor is used to collect the air pressure at the test point; the air flow rate sensor is used to collect the air flow rate at the test point; and the temperature sensor is used to collect the air temperature at the test point.

[0006] The data analysis module is used to determine the drag coefficient of the vehicle under different temperature environments based on the parameters of the air velocity sensor and the temperature sensor at the test point, the vehicle speed monitored by the GPS positioning module, and the vehicle front projection area and the wind resistance suffered by the vehicle at the corresponding vehicle speed provided by the data acquisition module; The compensation optimization module provides compensation for the data monitored by the main sensor at the same time according to the data monitored by the three correction sensors at each test point.

[0007] Furthermore, the data analysis module determines the drag coefficient of the vehicle at different sensor test positions and different temperature environments according to the vehicle speed, the air resistance received by the vehicle, the speed of the air flow and the front projection area of ​​the vehicle, so:

[0008] In the formula, It indicates the drag coefficient of the vehicle. It represents the air resistance of the vehicle at the corresponding speed. Indicates the air velocity measured at the test point. represents the frontal projection area of ​​the vehicle, Represents the air density at different sensor positions.

[0009] Furthermore, the data analysis module determines the air density at different test locations based on the temperature, gas constant of the air and air pressure measured by the sensors at different test locations, as follows:

[0010] In the formula, represents the air density at different sensor positions, is the gas constant of air, represents the temperature measured by the sensor at the test location, Indicates the air pressure at different sensor positions.

[0011] Furthermore, the compensation optimization module provides compensation for the data monitored by the main sensor at the same time according to the compensation data monitored by the three correction sensors at the corresponding time and the composition weights of the data detected by the three correction sensors, so:

[0012] In the formula, Represents the sensor data after data compensation by three calibration sensors, Indicates the data monitored by the main sensor. represents the data monitored by the i-th calibration sensor, represents the weight of the data detected by the i-th calibration sensor, Indicates the number of the calibration sensor.

[0013] Furthermore, the compensation optimization module determines the weight of the detected data according to the average value of the data collected by the straightening sensor at the same time, which is:

[0014] In the formula, represents the weight of the data detected by the i-th calibration sensor, represents the data monitored by the i-th calibration sensor, It represents the average value of the data collected by three alignment sensors at the same time.

[0015] Furthermore, the GPS positioning module is used to collect the real-time driving speed of the vehicle and feed the collected real-time speed back to the data analysis module.

[0016] Furthermore, the data acquisition module is used to obtain the front projection area of ​​the vehicle and the air resistance of the vehicle model at different vehicle speeds collected from the wind tunnel experiment.

[0017] A method for testing a vehicle drag coefficient testing system comprises the following steps: S1. Calculate the frontal projection area of ​​the vehicle and use the vehicle model to obtain the vehicle's air resistance in a wind tunnel experiment; S2. Four test positions are divided on the front of the vehicle, and each test position includes a main sensor and three calibration sensors; S3, collecting data from three correction sensors through the compensation optimization module, calculating the weight of the data collected by each correction sensor, and compensating the main sensor data according to the calculated weight; S4, feeding back the compensated collected data to the data analysis module; S5. The data analysis module analyzes the vehicle's drag coefficient according to the vehicle speed measured by the GPS and the vehicle front projection area and air resistance provided by the data acquisition module.

[0018] Beneficial effects: 1. The present invention uses more test points when testing the drag coefficient of a vehicle, and each test point can be tested under different climatic environments, which can make the wind resistance of the vehicle test more realistic, thereby ensuring that the vehicle's drag coefficient is closer to the actual situation.

[0019] 2. The present invention provides compensation for the data monitored by the main sensor at the same time by using three correction sensors to monitor compensation data at corresponding times and the composition weights of the data detected by the three correction sensors, so that the data monitored by the sensor at the test position is more consistent with the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the test position of the front side of the vehicle in the present invention; Figure 2 is a flow chart of the present invention; Figure 3 Schematic diagram of the main sensor and the calibration sensor at the test point 1 in the present invention. DETAILED DESCRIPTION

[0021] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 2 , 3 As shown, a method for testing a vehicle drag coefficient testing system comprises the following steps: Step 1: Calculate the front projection area of ​​the vehicle and use the vehicle model to obtain the vehicle's air resistance in a wind tunnel experiment.

[0023] Step 2: Four test positions are set up on the front of the vehicle, and each test position contains a main sensor and three calibration sensors. The main sensor and calibration sensor are composed of an air pressure sensor, an air velocity sensor, and a temperature sensor (such as Figure 3 as shown).

[0024] Step 3: Collect data from three correction sensors through the compensation optimization module, calculate the weight of the data collected by each correction sensor, and compensate the main sensor data according to the calculated weight.

[0025] Step 4: Feedback the compensated collected data to the data analysis module. The data analysis module analyzes the vehicle's drag coefficient based on the vehicle speed measured by the GPS and the vehicle front projection area and air resistance provided by the data acquisition module.

[0026] Example 1 like Figure 1 - As shown in Figure 3, according to one aspect of the present invention, a vehicle drag coefficient testing system is provided, including a data analysis module, a compensation optimization module, a GPS positioning module, a data acquisition module and a sensor; the sensor includes an air pressure sensor, an air flow rate sensor and a temperature sensor: the air pressure sensor is used to collect the air pressure at the test point; the air flow rate sensor is used to collect the air flow rate at the test point; the temperature sensor is used to collect the air temperature at the test point.

[0027] The data analysis module is used to determine the drag coefficient of the vehicle under different temperature environments based on the parameters of the air velocity sensor and temperature sensor at the test point, the vehicle speed monitored by the GPS positioning module, and the vehicle front projection area and the wind resistance of the vehicle at the corresponding speed provided by the data acquisition module; the compensation optimization module provides compensation for the data monitored by the main sensor at the same time based on the data monitored by the three correction sensors at each test point. The GPS positioning module is used to collect the real-time driving speed of the vehicle and feed the collected real-time speed back to the data analysis module. The data acquisition module is used to obtain the vehicle front projection area and the air resistance of the vehicle model at different speeds collected from the wind tunnel experiment.

[0028] Example 2 like Figure 1 As shown, the data analysis module determines the air density at different test locations based on the temperature, gas constant and air pressure measured by the sensors at different test locations, which are:

[0029] In the formula, represents the air density at different sensor positions, is the gas constant of air, represents the temperature measured by the sensor at the test location, Indicates the air pressure at different sensor positions.

[0030] The data analysis module determines the drag coefficient of the vehicle at different sensor test locations and different temperature environments based on the vehicle's speed, the air resistance received by the vehicle, the speed of the air flow, and the front projection area of ​​the vehicle. Then:

[0031] In the formula, It indicates the drag coefficient of the vehicle. It represents the air resistance of the vehicle at the corresponding speed. Indicates the air velocity measured at the test point. represents the frontal projection area of ​​the vehicle, Represents the air density at different sensor positions.

[0032] Among them, the data of the sensor at the test position 1 is collected. The temperature measured by the sensor at the test position 1 is (℃). The air pressure at the sensor position at test position 1 is (Pa). The gas constant of air is J / (kg·K). Then we have:

[0033] From the above calculation, we can know that the air density at test position 1 is ( ).

[0034] Among them, the air flow rate measured at test point 1 is (m / s). The air resistance of the vehicle at the corresponding speed is (N). The front projection area of ​​the vehicle is (㎡), then we have:

[0035] From the above calculation, we can know that taking the parameters of test position 1 as the reference index, the drag coefficient of the vehicle is . Then when other test positions are used as reference indicators, there are: From the above table data, we can know that due to factors such as engine heat, the air density and air flow rate above the vehicle will be different at different locations on the front of the vehicle. Therefore, when testing the vehicle's drag coefficient, more test points are needed to make the vehicle's wind resistance more realistic, so as to ensure that the vehicle's drag coefficient is closer to the actual situation.

[0036] Example 3 like Figure 3 As shown, the compensation optimization module determines the weight of the detected data according to the average value of the data collected by the straightening sensor at the same time, which is:

[0037] In the formula, represents the weight of the data detected by the i-th calibration sensor, represents the data monitored by the i-th calibration sensor, It represents the average value of the data collected by three alignment sensors at the same time.

[0038] The compensation optimization module provides compensation for the data monitored by the main sensor at the same time according to the compensation data monitored by the three correction sensors at the corresponding time and the composition weights of the data detected by the three correction sensors. Then:

[0039] In the formula, Represents the sensor data after data compensation by three calibration sensors, Indicates the data monitored by the main sensor. represents the data monitored by the i-th calibration sensor, represents the weight of the data detected by the i-th calibration sensor, Indicates the number of the calibration sensor.

[0040] The temperature sensor in the main sensor at test point 1 monitors the temperature of test position 1. The temperature parameter range of the main sensor is (℃), and the temperature parameters collected by calibration sensors 1, 2, and 3 are taken in turn (℃) (℃) (℃). Then we can take: , , , , so the average value of the data collected by the three alignment sensors at the same time is:

[0041] Then, the weight of the data detected by the i-th correction sensor is: Then we have:

[0042] From the above calculation, we can know that the sensor data after the data compensation of the three calibration sensors is (℃).

[0043] The above method provides compensation for the data monitored by the main sensor at the same time by monitoring the compensation data at the corresponding time through the three correction sensors and the composition weights of the data detected by the three correction sensors, so that the data monitored by the sensor at the test position is more consistent with the actual situation.

[0044] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A vehicle drag coefficient testing system, characterized in that: It includes data analysis module, compensation optimization module, GPS positioning module, data acquisition module and sensor; The sensor includes an air pressure sensor, an air flow rate sensor and a temperature sensor: the air pressure sensor is used to collect the air pressure at the test point; the air flow rate sensor is used to collect the air flow rate at the test point; the temperature sensor is used to collect the air temperature at the test point; The data analysis module is used to determine the drag coefficient of the vehicle under different temperature environments based on the parameters of the air velocity sensor and the temperature sensor at the test point, the vehicle speed monitored by the GPS positioning module, and the vehicle front projection area and the wind resistance suffered by the vehicle at the corresponding vehicle speed provided by the data acquisition module; The compensation optimization module provides compensation for the data monitored by the main sensor at the same time according to the data monitored by the three correction sensors at each test point.

2. The vehicle drag coefficient testing system according to claim 1, characterized in that: The data analysis module determines the drag coefficient of the vehicle at different sensor test positions and different temperature environments based on the vehicle speed, the air resistance received by the vehicle, the speed of air flow and the front projection area of ​​the vehicle. Then:

3. In the formula, It indicates the drag coefficient of the vehicle. It represents the air resistance of the vehicle at the corresponding speed. Indicates the air velocity measured at the test point. represents the frontal projection area of ​​the vehicle, Represents the air density at different sensor positions.

4. The vehicle drag coefficient testing system according to claim 2, characterized in that: The data analysis module determines the air density at different test locations based on the temperature, gas constant and air pressure measured by the sensors at different test locations, including:

5. In the formula, represents the air density at different sensor positions, is the gas constant of air, represents the temperature measured by the sensor at the test location, Indicates the air pressure at different sensor positions.

6. The vehicle drag coefficient testing system according to claim 1, characterized in that: The compensation optimization module provides compensation for the data monitored by the main sensor at the same time according to the compensation data monitored by the three correction sensors at the corresponding time and the composition weights of the data detected by the three correction sensors, so:

7. In the formula, Represents the sensor data after data compensation by three calibration sensors, Indicates the data monitored by the main sensor. represents the data monitored by the i-th calibration sensor, represents the weight of the data detected by the i-th calibration sensor, Indicates the number of the calibration sensor.

8. The vehicle drag coefficient testing system according to claim 4, characterized in that: The compensation optimization module determines the weight of the detected data according to the average value of the data collected by the straightening sensor at the same time, which is:

9. In the formula, represents the weight of the data detected by the i-th calibration sensor, represents the data monitored by the i-th calibration sensor, It represents the average value of the data collected by three alignment sensors at the same time.

10. The vehicle drag coefficient testing system according to claim 1, characterized in that: The GPS positioning module is used to collect the real-time driving speed of the vehicle and feed the collected real-time speed back to the data analysis module.

11. The vehicle drag coefficient testing system according to claim 1, characterized in that: The data acquisition module is used to acquire the front projection area of ​​the vehicle and the air resistance of the vehicle model at different vehicle speeds collected from a wind tunnel experiment.

12. A vehicle drag coefficient test system test method according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Calculate the frontal projection area of ​​the vehicle and use the vehicle model to obtain the vehicle's air resistance in a wind tunnel experiment; S2. Four test positions are divided on the front of the vehicle, and each test position includes a main sensor and three calibration sensors; S3, collecting data from three correction sensors through the compensation optimization module, calculating the weight of the data collected by each correction sensor, and compensating the main sensor data according to the calculated weight; S4, feeding back the compensated collected data to the data analysis module; S5. The data analysis module analyzes the vehicle's drag coefficient according to the vehicle speed measured by the GPS and the vehicle front projection area and air resistance provided by the data acquisition module.

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