Vehicle airtightness air volume test method

Abstract

The present invention relates to the technical field of vehicle performance testing, and discloses a vehicle airtightness air volume test method, which includes the following steps: Connect the vehicle to an air volume test bench, and set a first pressure measuring device to obtain the air volume and first supercharging value curve of the vehicle in the exhaust port sealed state and the air volume and second supercharging value curve of the vehicle in the exhaust port open state. Then, obtain the drain port supercharging value and second supercharging value curve in each mode and gear of the air conditioner, and the leakage area and vehicle air volume can be calculated. The vehicle airtightness air volume test method of the present invention comprehensively evaluates the vehicle airtightness performance and ventilation performance by calculating two indicators, namely the leakage area and the proportion of air outlet at the exhaust port, and solves the problem that the air volume of the internal circulation or partial internal circulation cannot be measured.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle performance testing, and particularly relates to a method for testing the airtightness air volume of a whole vehicle. Background Art

[0002] The existing mainstream methods for testing the airtightness and air volume of a whole vehicle are two separate tests. The airtightness evaluation method is also to seal the exhaust port and give a certain pressure inside the vehicle, and then test the leakage air volume of the whole vehicle. However, for the overall evaluation of the airtightness of the whole vehicle, the relationship between its leakage air volume and the pressure inside the vehicle is a curve, rather than a point, and there are sometimes certain errors in the evaluation results. In addition, this test method does not test the open state of the exhaust port and cannot evaluate the ventilation performance of the whole vehicle.

[0003] In terms of the detection of the airtightness of a whole vehicle, Liuzhou Wuling (CN 104865019A) proposed to create smoke inside the vehicle by arranging smoke cakes inside the vehicle, and continuously observe and record the smoke leakage parts around the outside of the whole vehicle after closing the doors and windows, and judge the sealing performance of the whole vehicle by the size of the smoke leakage. This method is extremely effective for finding the leakage position, but it cannot quantitatively judge the size of the leakage volume, nor can it evaluate the actual airtightness of the whole vehicle. While Shenlong Automobile (CN104792476A) proposed to seal the exhaust port of the whole vehicle, blow air into the vehicle through a wind volume device, give a pressure, and check the leakage volume of the air volume to judge the airtightness. Compared with the method of Liuzhou Wuling, it is more intuitive and effective to judge the airtightness of the whole vehicle by the size of the leakage air volume value. However, for the overall evaluation of the airtightness of the whole vehicle, the relationship between its leakage air volume and the pressure inside the vehicle is a curve, rather than a point, and there are sometimes certain errors in the evaluation results. In addition, this test method does not test the open state of the exhaust port and cannot evaluate the ventilation performance of the whole vehicle.

[0004] In terms of the air volume test of a whole vehicle, the traditional method generally measures the air volume of each air outlet by multiplying the air speed measured by an anemometer at each air outlet by the area, and then calculates the total air volume by linearly adding the air volumes of each air outlet. Due to reasons such as the irregular shape of the air duct and the air outlet, this method cannot ensure the uniformity of the air speed at the air outlet, so the calculation accuracy of the total air volume is not high, especially when the air conditioner is in a low gear, the accuracy is even worse.

[0005] Another air volume test method is to connect the whole vehicle and the air volume device with an air duct, and suck air through the air volume device to make the differential pressure between the cabin pressure and the atmosphere 0 (that is, the amount of air entering the vehicle is the same as the amount of air sucked away by the air volume device). Finally, the air volume recorded by the air volume device in the balanced state is the air volume of the whole vehicle. This method has a higher accuracy in the test result of the total air volume, but the pressure balance time is very long, and the air volume test at different gears takes a long time. In addition, in the internal circulation mode, the air volume of the whole vehicle is in a closed internal circulation closed loop (air enters from inside the vehicle and exits from the air outlet inside the vehicle), and back pressure cannot be established, and this method cannot test the air volume of the internal circulation or partial internal circulation. Summary of the Invention

[0006] The object of the present invention is to address the deficiencies of the above technologies by providing a method for testing the airtightness air volume of a whole vehicle. By calculating two indicators, namely the leakage area and the proportion of air flow at the exhaust port, the airtightness performance and ventilation performance of the whole vehicle are comprehensively evaluated, and the problem that the air volume of the internal circulation or partial internal circulation cannot be measured is solved.

[0007] To achieve the above object, the method for testing the airtightness air volume of a whole vehicle according to the present invention includes the following steps:

[0008] A) Test preparation: Place the vehicle statically in the test chamber, lower the glass of a front window of the vehicle, seal it with a sealing plate, and open a suitable round hole in the sealing plate to connect the air duct of the air volume test bench. A first pressure measuring device is provided inside the vehicle.

[0009] B) Seal the exhaust port of the vehicle with tape, set the air conditioner to the internal circulation mode and seal the air inlet of the front panel of the air conditioner with tape. Turn off the air conditioner, blow air into the vehicle through the air duct, gradually increase the air volume, and obtain the pressure difference between the inside of the vehicle and the external atmospheric pressure through the first pressure measuring device, which is recorded as the first pressure increase value. Record the air volume and the first pressure increase value to obtain the curve of the air volume and the first pressure increase value of the vehicle in the sealed exhaust port state.

[0010] C) Stop blowing air, remove the tape on the exhaust port, and then blow air through the air duct. Gradually increase the air volume, and obtain the pressure difference between the inside of the vehicle and the external atmospheric pressure through the first pressure measuring device, which is recorded as the second pressure increase value. Record the air volume and the second pressure increase value to obtain the curve of the air volume and the second pressure increase value of the vehicle in the open exhaust port state.

[0011] D) Stop blowing air, remove the sealing plate, close all the doors and windows, remove the tape on the air inlet of the front panel of the air conditioner, connect a second pressure measuring device to the air conditioner drain port through a rubber tube, turn on the external circulation mode of the air conditioner, and record the pressure difference between the inside of the vehicle and the external atmospheric pressure in each mode and each gear of the air conditioner through the first pressure measuring device, which is recorded as the second pressure increase value. Record the pressure difference between the drain port and the inside of the vehicle in each mode and each gear of the air conditioner through the second pressure measuring device, which is recorded as the drain port pressure increase value, and obtain the curve of the drain port pressure increase value and the second pressure increase value in each mode and each gear of the air conditioner.

[0012] E) Leakage area calculation: Due to the relationship of system air resistance: Obtain the equivalent leakage area In the formula, Δp is the first pressure increase value and the second pressure increase value in steps C) and D), with the unit of Pa, ρ is the air density, with the unit of kg / m 3 , v is the total air leakage velocity, Q m is the air volume blown by the blower, with the unit of kg / h, and the unit of S is cm 2, the equivalent leakage area in the exhaust port sealed state and the open state is obtained, and then the ratio of the equivalent leakage area in the exhaust port sealed state to the equivalent leakage area in the exhaust port open state is obtained, denoted as the leakage ratio. The lower the leakage ratio, the better the airtight performance of the whole vehicle;

[0013] F) Calculation of the total vehicle air volume: When the vehicle air conditioner is in the external circulation mode, according to the pressure difference between the inside of the vehicle and the external atmospheric pressure, that is, the second supercharging value, combined with the air volume and the second supercharging curve, the air volume of the air conditioner in the external circulation mode can be obtained, and substituting it into the drain port supercharging value and the second supercharging value curve, the drain port supercharging value and the air volume curve are obtained;

[0014] When the vehicle is in the internal circulation mode, the drain port supercharging value is obtained, and substituting it into the drain port supercharging value and the air volume curve, the air volume of the air conditioner in the internal circulation mode is obtained;

[0015] When the vehicle is in the partial internal circulation mode, the drain port supercharging value and the second supercharging value are obtained. Substituting the drain port supercharging value into the drain port supercharging value and the air volume curve to obtain the total air volume, and obtaining the air volume of the external circulation in the partial internal circulation mode by combining the second supercharging value air volume and the second supercharging curve. The internal circulation air volume is the total air volume minus the air volume of the external circulation in the internal circulation mode.

[0016] Preferably, in the step A), the first pressure measuring device is placed on the rear seat of the vehicle.

[0017] Preferably, in the steps B) and C), the air volume of the blower gradually increases from 100 kg / h to 600 kg / h, and the increment per step is 50 kg / h.

[0018] Preferably, in the step D), each mode of the air conditioner includes the external circulation face full cold, external circulation foot full heat, defrosting full heat and face full cold modes.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. Based on the overall vehicle wind resistance characteristics, the total leakage area of the whole vehicle can be obtained, which can more intuitively determine the airtightness and ventilation performance of the whole vehicle;

[0021] 2. Using the measured wind resistance characteristic line, based on the measured pressure values of the drain port and the vehicle interior under different mode gears, the corresponding air volume can be quickly calculated, supplementing the problem that the conventional air volume test cannot test the internal circulation and partial internal circulation air volume;

[0022] 3. The solved air resistance characteristic line can form a continuous curve to replace the original discrete air volume results, providing a method and basis for continuous recording of the air volume in the vehicle's loop mold. At the same time, the method of converting the air volume through pressure testing is simpler and more efficient than the direct measurement method of air volume, greatly shortening the test time. The air resistance characteristic curve can also be used for the subsequent design and selection of HVAC blowers, reducing the vehicle's power consumption and improving the NVH performance of the ventilation system. Description of the Drawings

[0023] Figure 1 It is the vehicle air resistance characteristic curve under two states of the exhaust port switch in the vehicle airtightness air volume test method of the present invention;

[0024] Figure 2 It is the fitting characteristic curve of the vehicle back pressure and the drainage port boost value versus the air volume under the external circulation mode of the present invention;

[0025] Figure 3 It is the function curve of the vehicle air volume versus the air conditioner drainage port and the vehicle back pressure under the face-blowing internal circulation mode of the present invention. Detailed Embodiment

[0026] The present invention will be further described in detail below with reference to specific embodiments.

[0027] A vehicle airtightness air volume test method includes the following steps:

[0028] A) Test preparation: Place the vehicle statically in the test chamber, lower the glass of one front window of the vehicle, seal it with a sealing plate, and open a suitable round hole on the sealing plate to connect the air duct of the air volume test bench. A first pressure measuring device is provided inside the vehicle;

[0029] B) Seal the exhaust port of the vehicle with tape, set the air conditioner to the internal circulation mode and seal the air inlet of the air conditioner front panel with tape, turn off the air conditioner, blow air into the vehicle through the air duct, gradually increase the air volume of the blower from 100 kg / h to 600 kg / h, with a step increase of 50 kg / h each time. Obtain the pressure difference between the inside of the vehicle and the external atmospheric pressure through the first pressure measuring device, record it as the first boost value, record the air volume and the first boost value, as shown in Table 1, obtain the curve of the air volume and the first boost value of the vehicle in the exhaust port sealed state, and organize it into a curve, as shown in Figure 1 the curve in the exhaust port closed state shown;

[0030] C) Stop the air blowing, remove the tape on the exhaust port, and then blow air through the air duct. The air volume of the blower gradually increases from 100 kg / h to 600 kg / h, with each step increasing by 50 kg / h. Obtain the pressure difference between the inside of the vehicle and the external atmospheric pressure through the first pressure measuring device, denoted as the second pressurization value. Record the air volume and the second pressurization value, as shown in Table 1. Obtain the curve of the air volume and the second pressurization value of the vehicle in the exhaust port open state, and organize it into a curve, as shown in Figure 1 The curve shown in the exhaust port open state:

[0031] Table 1: Vehicle wind resistance data with the exhaust port closed and open (the inside vehicle back pressure, i.e., the first pressurization value and the second pressurization value);

[0032]

[0033] D) Stop the air blowing, remove the sealing plate, close all the doors and windows, remove the tape on the air intake port of the air conditioner front panel, connect the second pressure measuring device through a rubber tube at the air conditioner drain port, turn on the air conditioner external circulation mode, record the pressure difference between the inside of the vehicle and the external atmospheric pressure in each mode and each gear of the air conditioner through the first pressure measuring device, denoted as the second pressurization value, and record the pressure difference between the drain port and the inside of the vehicle in each mode and each gear of the air conditioner through the second pressure measuring device, denoted as the drain port pressurization value. Obtain the curve of the drain port pressurization value and the second pressurization value in each mode and each gear of the air conditioner, as shown in Table 2;

[0034] Table 2: Vehicle external circulation air volume

[0035]

[0036] E) Leakage area calculation: Since there is a relationship in the system wind resistance: Obtain the equivalent leakage area In the formula, Δp is the first pressurization value and the second pressurization value in steps C) and D), with the unit of Pa, ρ is the air density, with the unit of kg / m 3 , v is the total air leakage flow rate, Q m is the air volume blown by the blower, with the unit of kg / h, and the unit of S is cm 2 , obtain the equivalent leakage areas in the exhaust port sealed state and the open state, and then obtain the ratio of the equivalent leakage area in the exhaust port sealed state to the equivalent leakage area in the exhaust port open state, denoted as the leakage ratio. The lower the leakage ratio, the better the airtight performance of the vehicle, as shown in Table 3;

[0037] Table 3: Calculation results of the vehicle airtightness leakage area

[0038]

[0039] F) Calculation of the total vehicle air volume: When the vehicle air conditioner is in the external circulation mode, according to the pressure difference between the inside and outside of the vehicle, that is, the second supercharging value, combined with the air volume and the second supercharging curve, the air volume of the air conditioner in the external circulation mode can be obtained. Substituting it into the curve of the drain port supercharging value and the second supercharging value, the curve of the drain port supercharging value and the air volume is obtained. As Figure 2 shown, the functional relationship between the fitted function air volume and pressure in this embodiment is y = -0.0082*x 2 + 3.8523*x + 120.78, where x is the drain port supercharging value in Pa, and y is the mass air volume in kg / h;

[0040] When the vehicle is in the internal circulation mode, the drain port supercharging value is obtained and substituted into the curve of the drain port supercharging value and the air volume to obtain the air volume of the air conditioner in the internal circulation mode;

[0041] When the vehicle is in the partial internal circulation mode, taking the face-blowing internal circulation as an example in this embodiment, combined with Figure 3 shown, the drain port supercharging value and the second supercharging value are obtained. The drain port supercharging value is substituted into the curve of the drain port supercharging value and the air volume to obtain the total air volume, and the second supercharging value air volume and the second supercharging curve are used to obtain the air volume of the external circulation in the partial internal circulation mode. The internal circulation air volume is the total air volume minus the air volume of the external circulation in the internal circulation mode.

[0042] Among them, in step A), the first pressure measuring device is placed on the rear seat of the vehicle to avoid the influence of the air pressure at the air conditioner outlet on the measurement result.

[0043] In steps B) and C), the air volume of the blower gradually increases from 100 kg / h to 600 kg / h, with each step increasing by 50 kg / h.

[0044] In addition, in step D), each mode of the air conditioner includes the external circulation face-blowing full cold, external circulation foot-blowing full heat, defrosting full heat, and face-blowing full cold modes.

[0045] The present invention obtains the total vehicle leakage area and the air outlet area of the exhaust port through the airtightness test, and more intuitively and clearly obtains the airtightness and ventilation performance of the whole vehicle. Then, based on the vehicle aerodynamic resistance characteristic curve and the function curve of the pressure difference between the drain port and the inside of the vehicle and the air volume, the pressure values in different gear modes are tested, and the total vehicle air volume results in different modes (including the internal circulation air volume) of the air conditioner are obtained. The test efficiency is higher and the test results are more accurate. It solves the problems that the position of the previous circulation air door cannot be accurately calibrated and the air volume cannot be continuously monitored and recorded. The environmental chamber test can accurately evaluate the influence of the air volume on the cooling or heating performance of the whole vehicle. The above is the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any method or replacement that can be easily thought of should be within the protection scope of this invention patent.

Claims

1. A method for testing the airtightness air volume of a whole vehicle, characterized in that: It includes the following steps: A) Test preparation: Place the vehicle statically in the laboratory, lower the glass of one front window of the vehicle, seal it with a sealing plate, and open a suitable round hole on the sealing plate to connect the air duct of the air volume test bench. A first pressure measuring device is provided inside the vehicle; B) Seal the exhaust port of the vehicle with tape, set the air conditioner to the internal circulation mode and seal the air inlet of the air conditioner front panel with tape. Turn off the air conditioner, blow air into the vehicle through the air duct, gradually increase the air volume, obtain the pressure difference between the inside of the vehicle and the external atmospheric pressure through the first pressure measuring device, record it as the first pressurization value, record the air volume and the first pressurization value, and obtain the air volume and the first pressurization value curve of the vehicle in the sealed exhaust port state; C) Stop blowing air, remove the tape on the exhaust port, and then blow air through the air duct. Gradually increase the air volume, obtain the pressure difference between the inside of the vehicle and the external atmospheric pressure through the first pressure measuring device, record it as the second pressurization value, record the air volume and the second pressurization value, and obtain the air volume and the second pressurization value curve of the vehicle in the open exhaust port state; D) Stop blowing air, remove the sealing plate, close all the doors and windows, remove the tape on the air inlet of the air conditioner front panel, connect a second pressure measuring device to the air conditioner drain port through a rubber tube, turn on the external circulation mode of the air conditioner, record the pressure difference between the inside of the vehicle and the external atmospheric pressure in each mode and each gear of the air conditioner through the first pressure measuring device, record it as the second pressurization value, record the pressure difference between the drain port and the inside of the vehicle in each mode and each gear of the air conditioner through the second pressure measuring device, record it as the drain port pressurization value, and obtain the drain port pressurization value and the second pressurization value curve in each mode and each gear of the air conditioner; E) Leakage area calculation: Due to the relationship of the system wind resistance: The equivalent leakage area is obtained In the formula, Δp is the first supercharging value and the second supercharging value in step C) and step D), with the unit of Pa, ρ is the air density, with the unit of kg / m 3 , v is the total flow velocity of air leakage, Q m is the air volume blown in by the blower, with the unit of kg / h, and the unit of S is cm 2 , the equivalent leakage areas in the sealed state and the opened state of the exhaust port are obtained, and then the ratio of the equivalent leakage area in the sealed state of the exhaust port to the equivalent leakage area in the opened state of the exhaust port is obtained, denoted as the leakage ratio. The lower the leakage ratio, the better the airtight performance of the whole vehicle; F) Calculation of the total vehicle air volume: When the vehicle air conditioner is in the external circulation mode, according to the pressure difference between the inside of the vehicle and the external atmospheric pressure, that is, the second pressurization value, combined with the air volume and the second pressurization curve, the air volume of the air conditioner in the external circulation mode can be obtained. Substitute it into the drain port pressurization value and the second pressurization value curve to obtain the drain port pressurization value and the air volume curve; When the vehicle is in the internal circulation mode, obtain the drain port pressurization value, substitute it into the drain port pressurization value and the air volume curve, and obtain the air volume of the air conditioner in the internal circulation mode; When the vehicle is in the partial internal circulation mode, obtain the drain port pressurization value and the second pressurization value. Substitute the drain port pressurization value into the drain port pressurization value and the air volume curve to obtain the total air volume. Obtain the air volume of the external circulation in the partial internal circulation mode from the second pressurization value air volume and the second pressurization curve. The internal circulation air volume is the total air volume minus the air volume of the external circulation in the internal circulation mode.

2. The vehicle airtightness air volume test method according to claim 1, characterized in that: In the step A), the first pressure measuring device is placed on the rear seat of the vehicle.

3. The vehicle airtightness air volume test method according to claim 1, characterized in that: In the steps B) and C), the air volume of the blower gradually increases from 100 kg / h to 600 kg / h, and the increase in each step is 50 kg / h.

4. The method for testing the airtightness air volume of a whole vehicle according to claim 1, characterized in that: In the step D), each mode of the air conditioner includes the external circulation blowing face full cold, external circulation blowing feet full heat, defrosting full heat and blowing face full cold modes.

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