A method and device for simulating air tightness test of a whole vehicle equipped with a rubber tube

Abstract

The application provides a kind of rubber pipe whole vehicle equipment simulation airtight test method and detection device, belongs to sealed detection technical field, method includes: first step, preparation stage, continuously monitor the pressure change value in pipe, when change value approaches zero, establish physical zero point, record initial pressure;Second step, low pressure detection, total control valve switches low pressure gas source, fast inflation to low pressure target value, detection record data, calculate leakage rate;If leakage rate is greater than or equal to set threshold, it is judged as unqualified, then terminate detection and deflation;If leakage rate is less than set threshold, it is judged as qualified, enter next step;Third step, high pressure detection, for low pressure qualified product, total control valve switches high pressure gas source with pressure, does not deflate directly to high pressure target value, detection is carried out.This method uses the control device that can switch with pressure, continuously detects low pressure and high pressure for pipe, ensures that the quality of pipe leaving factory is reliable, and does not need secondary detection, detection efficiency is high.

Description

Technical Field

[0001] This application belongs to the field of water pipe quality testing technology, and relates to sealing testing, specifically a method and testing device for simulating airtightness testing of rubber hoses in a vehicle. Background Technology

[0002] The engine water hose uses a three-layer composite rubber hose and is an important component connecting the engine, radiator, thermostat, and heater core. As the core component of the cooling system, the engine water hose must undergo rigorous physical and chemical performance verification to ensure that it will not burst or leak under extreme environments of high temperature, high pressure, and vibration.

[0003] During production, engine water hoses undergo multiple testing steps, including appearance, airtightness, explosion-proof performance, joint reliability, aging resistance, and pressure resistance. Airtightness testing is a mandatory requirement for all hoses, and the experiment is divided into high-pressure and low-pressure tests. High-pressure airtightness testing on the production line is done by sampling, simulating extreme pressure shocks to the cooling system under fault conditions (such as thermostat failure or overheating). Products that pass the high-pressure airtightness test are usually considered airtight and do not require a second airtightness test.

[0004] However, subsequent customer feedback and investigations revealed that the rubber hoses installed in the vehicle operate at low pressure most of the time in real-world environments, only operating at high pressure in extreme cases. However, actual testing showed that some water hoses that passed high-pressure testing without leaks actually leaked under normal pressure. Research has identified this phenomenon as "pressure-compensated pseudo-compliance." Specifically, when there are tiny gaps in the water hose or joint, uneven sealing surfaces, or defects in the O-ring groove design, the strong air pressure forces the soft rubber material against the sealing surface or joint wall. This pressure acts like an invisible hand, flattening and sealing the existing gaps. At this point, the elastic sealing force generated by the rubber's deformation under pressure overshadows the leakage, and the pressure drop detected by the sensor is very small, thus deeming it acceptable. However, when returning to low-pressure operation, the elastic deformation of the rubber is insufficient to fill the gaps, and gas leaks through these tiny channels. In short, high-pressure testing cannot detect minute flaws or defects in the internal channels of the hoses. However, if the hoses are subjected to high-pressure and low-pressure tests separately, the operation process will be significantly more difficult, resulting in low overall testing efficiency. Summary of the Invention

[0005] Based on the shortcomings and problems of existing technologies, this application provides a simulated airtightness test method for rubber hoses in vehicle equipment, which can simulate the high and low pressure switching scenario of the vehicle equipment state and ensure the accuracy of the test results.

[0006] The purpose of this application is achieved as follows: A method for simulating airtightness testing of rubber hoses in vehicle equipment, the specific steps of which are as follows: The first step, the preparation stage, involves continuously monitoring the pressure changes inside the pipe fittings. Once the pressure changes reach a stable state, a physical zero point is established, and the initial pressure is recorded. The second step is low-pressure testing. The main control valve switches to the low-pressure gas source, and the gas is filled to the low-pressure target value. The data is recorded and the leakage rate is calculated. If the leakage rate is greater than or equal to the set threshold, it is judged as unqualified, and the test is terminated and the gas is released. If the leakage rate is less than the set threshold, it is judged as qualified and proceeds to the next step. The third step is high-pressure testing. For products that pass the low-pressure test, the main control valve is switched to the high-pressure air source while under pressure. Without releasing air, the pressure is directly replenished to the high-pressure target value. After the pressure stabilizes, high-pressure testing is performed, and the pressure change curve is output.

[0007] Furthermore, the specific steps for detecting the leakage rate under low pressure include: After rapidly inflating to the target low pressure value, perform a 1.5s pressure stabilization and balancing process to eliminate the effects of temperature rise. Once the change value approaches zero, continue for 2 seconds to monitor and record the data. Record the stable low pressure P1, the ambient temperatures T0 and T1 at the start and end of the monitoring, and record the atmospheric pressure P during the monitoring using a barometer. atm ; Based on the ideal gas law, considering the effect of temperature change on pressure, the initial pressure P0 is first corrected to the corrected initial pressure P at the same temperature as the steady-state pressure measurement time. 0修正 ; In the formula, P0 is the initial pressure; Then calculate the pressure change after considering atmospheric pressure and temperature correction. : The leakage rate L is calculated using the following formula: , Leakage rate represents the relative proportion of pressure change per unit time. If the calculated leakage rate is within the allowable range, the water pipe is considered to be airtight and there is no obvious small leak; if it exceeds the range, it is judged that there is a small leak.

[0008] Furthermore, the specific steps of the high-voltage detection are as follows: After passing the low-pressure test, record the current pressure value inside the water pipe, and denote it as the starting pressure P of the high-pressure test. low-end The preset high-pressure detection target pressure value is denoted as P. high-set ; During the process of increasing the pressure from the low-pressure final pressure to the high-pressure set pressure, the pressure value P in the water pipe is recorded at fixed time intervals. tThis forms pressure-time series data; After reaching the set high pressure, maintain the pressure for a period of time to allow it to stabilize, and record the stable pressure value in the water pipe during this period, denoted as P. high-stable ; During the test, changes in ambient temperature will affect the gas pressure. Record the ambient temperature T once at the end of the low-pressure test. low-end Record the ambient temperature T again during the high-pressure stabilization phase. high-stable Based on the ideal gas law, the temperature change is corrected. First, the final pressure P of the low-pressure detection is... low-end The pressure P is adjusted to the same temperature as the high-pressure steady-state phase. low-corrected : , Then calculate the corrected pressure change ΔP. corrected : , The pressure drop rate R during the high-pressure steady-state phase is calculated using the following formula: , In the formula, ΔP corrected This is the corrected pressure change, t stable This refers to the entire high-pressure stabilization phase. Plot a pressure-time curve using the pressure change data during the pressurization process, and observe whether the pressure increase trend is smooth and linear. If the curve shows abnormal fluctuations, it may indicate problems such as local blockage, gas leakage, or measurement error inside the water pipe.

[0009] A simulated airtightness testing device for rubber hoses in vehicles, used to implement the simulated airtightness testing method for rubber hoses in vehicles as described in claim 1, includes a main control valve, an inflation connector, a safety chamber, a quick-connect connector, and an electronic control module. The main control valve has two inlets and one outlet. The two inlets are connected to a high-pressure gas source and a low-pressure gas source, respectively. The outlet is connected to an inflation connector via a pipeline. The inflation connector is located inside the safety chamber, which also contains a quick-connect connector. The inflation connector and the quick-connect connector are used to seal both ends of the pipe fitting to be tested, so that the cavity inside the pipe fitting forms a closed inner cavity that communicates with the gas path inside the pipeline. A pressure sensor is installed inside the inflation connector and / or the quick-connect connector. The pressure sensor is electrically connected to the electronic control module via a circuit, and the electronic control module is electrically connected to the control terminal of the main control valve.

[0010] Furthermore, the main control valve includes a valve body, a gate, and a valve seat. The valve body has a first channel and a second channel respectively connecting to high-pressure and low-pressure gas sources. A third channel is located in the middle of the other side of the valve body. Both the first and second channels are longitudinal channels, and they are connected to the third channel, which connects to the gas outlet. A gate is transversely located in the middle of the valve body, with one end extending outwards to connect to the control end of the main control valve. The gate's installation position within the valve body sequentially passes transversely through the first and second channels and can block either the first or second channel. Valve seats are installed in the corresponding first and second channels on both sides of the gate, with the valve seats abutting against the gate. An annular spring abuts between the valve seats and the longitudinal contact ends of the first or second channel. Multiple annular packings are spaced apart on the outer periphery of the valve seats in the first and second channels, in contact with the valve body.

[0011] Furthermore, the gate is provided with a first through hole and a second through hole at intervals in the middle. The distance between the first through hole and the second through hole is greater than the distance between the first channel and the second channel. Moving the gate can switch between the first channel and the second channel, thereby switching between the high-pressure gas source and the low-pressure gas source.

[0012] Furthermore, valve seats with high-pressure sealing structures are installed in the second channels on both sides of the gate. Specifically, an annular groove is provided in the valve body corresponding to the axial end face of the valve seat, and an O-ring is pressed in the annular groove. A hard sealing layer is provided on the longitudinal end face of the valve seat that contacts the gate, and an annular buffer groove is provided at the end of the valve seat that contacts the gate.

[0013] Furthermore, a buffer groove is provided in the middle of the valve body between the first channel and the second channel.

[0014] Furthermore, the interface body of the inflation connector is provided with a transverse gas channel. One end of the interface body is connected to the gas outlet of the main control valve through a pipeline, and the other end of the interface body is coaxially and sealed to a pressure sleeve. The end of the pressure sleeve is provided with a sealing socket that mates with the pipe fitting. A high-pressure sealing assembly is provided inside the pressure sleeve. The high-pressure sealing assembly includes a pressure block, a first end plate, a spring, and a second end plate. The first end plate and the second end plate are spaced apart inside the pressure sleeve, and a spring connects the first end plate and the second end plate. The second end plate is provided with a limiting groove that can seal with the pipe fitting port, and a through hole is provided in the middle of the second end plate. A pressure block that can move laterally back and forth is provided inside the transverse gas channel of the interface body. A through hole is provided in the middle of the pressure block, through which gas can pass. The pressure block can move back and forth within the gas channel. When the gas pressure increases, the pressure block moves and squeezes the first end plate. The first end plate moves, thereby driving the second end plate to press the pipe fitting port. The second end plate further forms a high-pressure seal on the pipe opening inside the pressure sleeve.

[0015] Furthermore, a detection tube is connected to the radial side of the interface body, and the detection tube is connected to the inner cavity of the interface body to collect the internal gas pressure in real time.

[0016] In summary, the technical solutions provided in the embodiments of this application have the following technical effects or advantages: This device and method employs a control unit that can switch between low and high pressure to continuously test pipe fittings, ensuring the reliability of the quality of pipe fittings leaving the factory. Moreover, it eliminates the need for secondary testing and has high testing efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the detection device of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of the main control valve.

[0019] Figure 3 yes Figure 2 A magnified view of part M in the middle.

[0020] Figure 4 This is a schematic diagram of the inflation connector (low pressure).

[0021] Figure 5 This is a schematic diagram of the air inflator (high pressure).

[0022] Reference numerals: 1. Main control valve; 2. Inflation connector; 3. Safety chamber; 4. Quick-connect connector; 5. Electrical control module; 6. Pipe fitting; 11. Valve body; 12. Gate; 13. Valve seat; 14. Annular spring; 15. Cavity; 16. Elastic element; 17. Hard sealing layer; 18. Buffer groove; 19. Sealing packing; 21. Interface body; 22. Pressure block; 23. First end plate; 24. Pressure sleeve; 25. Spring; 26. Second end plate; 27. Detection tube. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0024] A method for simulating airtightness testing of rubber hoses in vehicle equipment, the specific steps of which are as follows: The first step, the preparation stage, involves continuously monitoring the pressure changes inside the pipe fittings. When the pressure changes reach a stable state, a physical zero point is established, and the initial pressure is recorded as P0. The second step is low-pressure detection. The main control valve switches to the low-pressure gas source, quickly filling the gas to the target low-pressure value, which is set to 30 kPa in this embodiment, but is usually 10-50 kPa. A 1.5-second pressure stabilization and balancing process is performed to eliminate the influence of temperature rise. Once the change value approaches zero, the data is monitored and recorded for another 2 seconds, recording the stable low-pressure pressure P1. The ambient temperatures T0 and T1 at the start and end of the test were recorded using a barometer, and the atmospheric pressure P during the test was recorded. atm , Based on the ideal gas law, consider the effect of temperature change on pressure. First, correct the initial pressure P0 to the corrected initial pressure P at the same temperature as the steady-state pressure measurement time. 0修正 ; , Then calculate the pressure change after considering atmospheric pressure and temperature correction. : The leakage rate L is calculated using the following formula: Leakage rate represents the relative proportion of pressure change per unit time. Different types of engine water hoses have different allowable leakage rate ranges, generally between 0.5% and 2% per minute. If the calculated leakage rate is within the allowable range, the water hose can be considered to have good airtightness and no obvious small leaks; if it exceeds the range, it is judged that there are small leaks. If the leakage rate reaches or exceeds the set threshold, it is deemed unqualified, and the program will shut off and release the gas. Under low pressure, the rubber hose deforms very little, and the calculated initial leakage rate is closest to the actual physical value. If the low-pressure test fails, it indicates that there are holes in the pipeline or the joints are not sealed, and the pipe should be scrapped directly without high-pressure testing.

[0025] If the leakage rate is less than the set threshold, it is considered qualified and proceeds to the next step.

[0026] The third step is high-pressure testing. For products that pass the low-pressure test, the main control valve is switched to the high-pressure air source while under pressure. Without releasing air, the pressure is directly increased to the target high-pressure value. After the pressure stabilizes, high-pressure testing is performed. The purpose of this test is primarily to detect pinholes, micro-cracks, or material leakage under high pressure within the rubber layer. The specific steps are as follows: When the low-pressure test passes, record the pressure value inside the water pipe at this time, and denote it as the starting pressure P of the high-pressure test. low-end The preset high-pressure detection target pressure value is denoted as P. high-set In this embodiment, the detection pressure is set to 300 kPa, while the pressure setting for high-pressure detection is usually 200-400 kPa.

[0027] During the process of increasing the pressure from the low-pressure final pressure to the high-pressure set pressure, the pressure value Pt in the water pipe is recorded at certain time intervals (e.g., every 1-5 seconds) to form pressure-time series data. If the pressure increases too quickly or too slowly, it may indicate a malfunction in the air filling equipment or abnormal resistance in the water pipe.

[0028] After reaching the set high pressure, maintain it for a period of time (e.g., 3-10 minutes) to allow the pressure to stabilize. Record the stable pressure value in the water pipe during this period, denoted as P. high-stable During the test, changes in ambient temperature will affect the gas pressure. Record the ambient temperature T once at the end of the low-pressure test. low-end Record the ambient temperature T again during the high-pressure stabilization phase. high-stable Based on the ideal gas law, the temperature change is corrected. First, the final pressure P of the low-pressure detection is... low-end The pressure P is adjusted to the same temperature as the high-pressure steady-state phase. low-corrected : , Then calculate the corrected pressure change ΔP. corrected : , The pressure drop rate R during the high-pressure steady-state phase is calculated using the following formula: , In the formula, ΔP corrected This is the corrected pressure change, t stable This refers to the entire high-pressure stabilization phase. Plot a pressure-time curve using the pressure change data during the pressurization process, and observe whether the pressure increase trend is smooth and linear. Abnormal fluctuations in the curve may indicate problems such as localized blockages, gas leaks, or measurement errors inside the water pipes.

[0029] The step-by-step pressure boosting process, which involves testing at low pressure first and then at high pressure, balances testing accuracy with equipment safety.

[0030] The following variables are captured in real time using sensors: Real-time pressure (P): Acquired by a high-precision pressure transmitter with an accuracy of 0.05% FS or higher.

[0031] Real-time temperature (T): Monitors the temperature of the test medium or environment. A temperature fluctuation of 1°C will directly cause a significant shift in air pressure.

[0032] Acquisition time (t): High-frequency sampling, with a frequency of 10Hz or higher, to capture the instantaneous slope of the pressure drop.

[0033] See appendix Figure 1As shown, this embodiment also provides a simulated airtightness testing device for rubber hoses in vehicles, used to implement the above-mentioned simulated airtightness testing method for rubber hoses in vehicles. The device includes a main control valve 1, an inflation connector 2, a safety chamber 3, a quick-connect connector 4, and an electronic control module 5. The main control valve 1 has two inlets and one outlet. The two inlets of the main control valve 1 are connected to a high-pressure gas source and a low-pressure gas source, respectively. The outlet of the main control valve 1 is connected to an inflation connector 2 via a pipeline. The inflation connector 2 is located inside the safety chamber 3. The safety chamber 3 is also equipped with a quick-connect connector 4. The inflation connector 2 and the quick-connect connector 4 are used to seal both ends of the tube 27 to be tested 6, so that the cavity inside the tube 6 forms a closed inner cavity that is connected to the gas passage inside the pipeline. The tube 6 to be tested is tested inside the safety chamber 3 to prevent the danger of high-pressure explosion.

[0034] Pressure sensors are installed inside the inflation connector 2 and / or quick-connect connector 4. The pressure sensors are electrically connected to the electronic control module 5 via wiring. At the same time, the electronic control module 5 is electrically connected to the control terminal of the main control valve 1.

[0035] An infrared temperature sensor is installed inside the safety chamber 3 to detect the temperature of the pipe fitting 6.

[0036] See appendix Figure 2 , Figure 3 The diagram shows the internal structure of the main control valve 1. The main control valve 1 can switch between high and low pressure air sources under pressure. The main control valve 1 includes a valve body 11, a gate 12, and a valve seat 13. A first channel A and a second channel B are provided inside the valve body 11. A third channel C is provided in the middle of the other side inside the valve body 11. Both the first channel A and the second channel B are longitudinal channels. One end of the first channel A and the second channel B is provided with a gas inlet that connects to the outside of the valve body 11. The other end of the first channel A and the second channel B are connected to the third channel C. The other longitudinal end of the third channel C is connected to the gas outlet. A gate 12 is arranged laterally in the middle of the valve body 11. One end of the gate 12 extends to the control end of the main control valve 1 outside the valve body 11. The control end is equipped with a motor and a handwheel, which can drive the gate 12 to move laterally back and forth.

[0037] The gate 12 inside the valve body 11 is installed laterally through the first channel and the second channel, and the gate 12 can block either the first channel or the second channel. Specifically, the gate 12 has a first through hole and a second through hole spaced apart in the middle, and the distance between the first through hole and the second through hole is greater than the distance between the first channel and the second channel. Moving the gate 12 can switch between the first channel and the second channel, thereby switching between a high-pressure air source and a low-pressure air source.

[0038] See appendix Figure 2As shown, when the first through hole is aligned with the first channel, the second through hole is misaligned with the second channel, and the gate 12 closes the second channel. When it is necessary to switch the air source, the second channel and the second channel are aligned and connected, and the gate 12 closes the first channel.

[0039] To ensure sealing, valve seats 13 are installed in the corresponding second channels on both sides of the gate 12. The valve seats 13 abut against the gate 12, and the annular spring 14 abuts against the longitudinal contact end of the valve seats 13 and the second channel to maintain pressure sealing contact between the valve seats 13 and the gate 12.

[0040] The first channel is used to connect to a high-pressure gas source; see appendix. Figure 3 As shown, valve seats 13 with high-pressure sealing structures are installed in the second channels on both sides of the gate 12. Specifically, an annular groove is provided in the valve body 11 corresponding to the axial end face of the valve seat 13, and an O-ring is pressed in the annular groove, which together with the annular spring 14 provides pressure sealing contact for the valve seat 13. A hard sealing layer 17 is provided on the longitudinal end face of the valve seat 13 that contacts the gate 12 to improve the sealing effect. An annular buffer groove 18 is provided at the end of the valve seat 13 that contacts the gate 12. The buffer groove 18 can compensate for the deformation of the valve seat 13 when the high-pressure airflow is applied, thereby improving the durability of the valve seat 13.

[0041] A buffer groove 18 is provided in the middle of the valve body 11 between the first channel and the second channel to reduce the contact area between the gate 12 and the valve body 11, reduce resistance, and ensure smooth sliding.

[0042] Multiple annular packings are provided at intervals on the outer periphery of the valve seat 13 in the first and second channels and the contact surface with the valve body 11 to ensure the sealing performance of the valve seat 13.

[0043] See appendix Figure 4 , 5 As shown, the air inflator 2 automatically switches between high-pressure and low-pressure testing to ensure the reliability of the test and avoid excessive sealing pressure at low pressure.

[0044] The interface body 21 of the air inflator 2 is provided with a transverse gas channel. One end of the interface body 21 is connected to the gas outlet of the main control valve 1 through a pipeline. The other end of the interface body 21 is coaxially and sealed with a pressure sleeve 24. The end of the pressure sleeve 24 is provided with a sealing socket that mates with the fitting 6. A high-pressure sealing assembly is provided inside the pressure sleeve 24. The high-pressure sealing assembly includes a pressure block 22, a first end plate 23, a spring 25, and a second end plate 26. The first end plate 23 and the second end plate 26 are spaced apart inside the pressure sleeve 24. The spring 25 connects the first end plate and the second end plate 26. The second end plate 26 is provided with a limiting groove that can seal with the port of the pipe fitting 6. A through hole is provided in the middle of the second end plate 26. A pressure block 22 capable of reciprocating laterally is provided in the transverse gas channel of the interface body 21. The pressure block 22 has a through hole in the middle. When a low-pressure gas source is connected, the gas can pass through the through hole in the middle of the pressure block 22 without the pressure block 22 itself moving. When high-pressure gas is filled in, the pressure block 22 can move in the gas channel. When the gas pressure increases, the pressure block 22 moves and squeezes the first end plate 23. The first end plate 23 moves, thereby driving the second end plate 26 to press the port of the pipe fitting 6. The second end plate 26 further forms a high-pressure seal on the pipe opening in the pressure sleeve 24 to ensure the reliability of the seal.

[0045] The outer edge of the second end slides into contact with the inner wall of the pressure sleeve 24, and the spring 25 acts as a buffer against the pressure. When the high pressure is released, the spring 25 is released from its compressed state and returns to its original position, pushing the pressure block 22 back towards the interface body 21.

[0046] When the low-pressure gas source is connected, the high-pressure sealing component has no pressure contact with the end of the pipe 6, and only the pressure sleeve 24 maintains a single-layer seal.

[0047] A detection tube 27 is also connected to the radial side of the interface body 21. The detection tube 27 is connected to the inner cavity of the interface body 21 and can collect the internal gas pressure in real time.

[0048] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of other embodiments of this disclosure upon considering the specification and the disclosure of practical truth. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A method for simulating airtightness testing of rubber hoses in a vehicle assembly, characterized in that, The specific steps are as follows: The first step, the preparation stage, involves continuously monitoring the pressure changes inside the pipe fittings. Once the pressure changes reach a stable state, a physical zero point is established, and the initial pressure is recorded. The second step is low-pressure testing. The main control valve switches to the low-pressure gas source, and the gas is filled to the low-pressure target value. The data is recorded and the leakage rate is calculated. If the leakage rate is greater than or equal to the set threshold, it is judged as unqualified, and the test is terminated and the gas is released. If the leakage rate is less than the set threshold, it is considered qualified and proceeds to the next step; The third step is high-pressure testing. For products that pass the low-pressure test, the main control valve is switched to the high-pressure air source while under pressure. Without releasing air, the pressure is directly replenished to the high-pressure target value. After the pressure stabilizes, high-pressure testing is performed, and the pressure change curve is output.

2. The method for simulating airtightness testing of rubber hoses in a vehicle according to claim 1, characterized in that, The leakage rate detection under low pressure includes the following specific steps: After rapidly inflating to the target low pressure value, perform a 1.5s pressure stabilization and balancing process to eliminate the effects of temperature rise. Once the change value approaches zero, continue for 2 seconds to monitor and record the data. Record the stable low pressure P1, the ambient temperatures T0 and T1 at the start and end of the monitoring, and record the atmospheric pressure P during the monitoring using a barometer. atm ; Based on the ideal gas law, considering the effect of temperature change on pressure, the initial pressure P0 is first corrected to the corrected initial pressure P at the same temperature as the steady-state pressure measurement time. 0修正 ; ， In the formula, P0 is the initial pressure. Then calculate the pressure change after considering atmospheric pressure and temperature correction. : The leakage rate L is calculated using the following formula: , Leakage rate represents the relative proportion of pressure change per unit time. If the calculated leakage rate is within the allowable range, the water pipe is considered to be airtight and there is no obvious small leak; if it exceeds the range, it is judged that there is a small leak.

3. The method for simulating airtightness testing of rubber hoses in a vehicle according to claim 1, characterized in that, The specific steps for the high-voltage detection are as follows: After passing the low-pressure test, record the current pressure value inside the water pipe, and denote it as the starting pressure P of the high-pressure test. low-end The preset high-pressure detection target pressure value is denoted as P. high-set ; During the process of increasing the pressure from the low-pressure final pressure to the high-pressure set pressure, the pressure value P in the water pipe is recorded at fixed time intervals. t This generates pressure-time series data; after reaching the high-pressure set pressure, it is maintained for a period of time to stabilize the pressure, and the stable pressure value in the water pipe during this period is recorded as P. high-stable ; During the test, changes in ambient temperature will affect the gas pressure. Record the ambient temperature T once at the end of the low-pressure test. low-end Record the ambient temperature T again during the high-pressure stabilization phase. high-stable Based on the ideal gas law, the temperature change is corrected. First, the final pressure P of the low-pressure detection is... low-end The pressure P is adjusted to the same temperature as the high-pressure steady-state phase. low-corrected : ， Then calculate the corrected pressure change ΔP. corrected : ， The pressure drop rate R during the high-pressure steady-state phase is calculated using the following formula: ， In the formula, ΔP corrected This is the corrected pressure change, t stable This refers to the entire high-pressure stabilization phase. Plot a pressure-time curve using the pressure change data during the pressurization process, and observe whether the pressure increase trend is smooth and linear; if the curve shows abnormal fluctuations, it indicates that there is a problem inside the water pipe.

4. A simulated airtightness testing device for a rubber hose in a vehicle, characterized in that, The method for simulating airtightness testing of rubber hoses in a vehicle as described in claim 1 includes a main control valve, an inflation connector, a safety chamber, a quick-connect connector, and an electronic control module. The main control valve has two inlets and one outlet. The two inlets are connected to a high-pressure gas source and a low-pressure gas source, respectively. The outlet is connected to an inflation connector via a pipeline. The inflation connector is located inside the safety chamber, which also contains a quick-connect connector. The inflation connector and the quick-connect connector are used to seal both ends of the pipe fitting to be tested, so that the cavity inside the pipe fitting forms a closed inner cavity that communicates with the gas path inside the pipeline. A pressure sensor is installed inside the inflation connector and / or the quick-connect connector. The pressure sensor is electrically connected to the electronic control module via a circuit, and the electronic control module is electrically connected to the control terminal of the main control valve.

5. The vehicle equipment simulated airtightness testing device for rubber hoses according to claim 4, characterized in that, The main control valve includes a valve body, a gate, and a valve seat. The valve body has a first channel and a second channel respectively connecting to high-pressure and low-pressure gas sources. A third channel is located in the middle of the other side of the valve body. Both the first and second channels are longitudinal channels, and they are connected to the third channel, which leads to the gas outlet. A gate is transversely located in the middle of the valve body, with one end extending outwards to connect to the control end of the main control valve. The gate's position within the valve body transversely passes through the first and second channels and can block either the first or second channel. Valve seats are installed in the corresponding first and second channels on both sides of the gate, abutting against the gate. An annular spring abuts between the valve seat and the longitudinal contact end of the first or second channel. Multiple annular packing rings are spaced apart on the outer periphery of the valve seats in the first and second channels, on the contact surface with the valve body.

6. The vehicle equipment simulated airtightness testing device for rubber hoses according to claim 5, characterized in that, The gate is provided with a first through hole and a second through hole at intervals in the middle. The distance between the first through hole and the second through hole is greater than the distance between the first channel and the second channel. Moving the gate can switch between the first channel and the second channel, thereby switching between the high-pressure gas source and the low-pressure gas source.

7. The vehicle equipment simulated airtightness testing device for rubber hoses according to claim 5, characterized in that, Valve seats with high-pressure sealing structures are installed in the second channels on both sides of the gate. Specifically, an annular groove is provided in the valve body corresponding to the axial end face of the valve seat, and an O-ring is pressed in the annular groove. A hard sealing layer is provided on the longitudinal end face of the valve seat that contacts the gate, and an annular buffer groove is provided at the end of the valve seat that contacts the gate.

8. The vehicle equipment simulated airtightness testing device for rubber hoses according to claim 5, characterized in that, A buffer groove is provided in the middle of the valve body between the first channel and the second channel.

9. The vehicle equipment simulated airtightness testing device for rubber hoses according to claim 4, characterized in that, The inflatable connector has a transverse gas channel within its interface body. One end of the interface body is connected to the gas outlet of the main control valve via a pipeline, and the other end of the interface body is coaxially and sealed to a pressure sleeve. The end of the pressure sleeve has a sealing socket that mates with the pipe fitting. A high-pressure sealing assembly is installed inside the pressure sleeve, comprising a pressure block, a first end plate, a spring, and a second end plate. The first and second end plates are spaced apart within the pressure sleeve, and a spring connects the first and second end plates. The second end plate has a limiting groove that seals with the pipe fitting port, and a through hole in its center. A pressure block capable of transverse reciprocating movement is installed within the transverse gas channel of the interface body. The pressure block has a through hole in its center, allowing gas to pass through. The pressure block reciprocates within the gas channel. When the gas pressure increases, the pressure block moves and presses against the first end plate, which in turn moves and causes the second end plate to press against the pipe fitting port. The second end plate further forms a high-pressure seal on the pipe opening within the pressure sleeve.

10. The vehicle assembly simulated airtightness testing device for rubber hoses according to claim 9, characterized in that, A detection tube is also connected to the radial side of the interface body. The detection tube is connected to the inner cavity of the interface body and can collect the internal gas pressure in real time.

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