Method and apparatus for detecting leaks during vehicle fluid filling

Abstract

The present invention relates to a method for detecting leaks during the process of filling a vehicle with a fluid. The method includes a positive pressure process, a negative pressure process, and a filling process. By means of a filling gun, high-pressure gas is respectively charged into the fluid pipeline system of the vehicle, vacuum is pumped, and the fluid is filled through the fluid filling port of the vehicle during the positive pressure process, the negative pressure process, and the filling process. The method includes: respectively collecting, at least in part of the time period, the curves of the change of pressure with time during the positive pressure process and the negative pressure process through a sensor provided in the filling gun barrel; based on the analysis of the characteristics of the collected change curves, determining whether there is a leak during the process of filling the vehicle with the fluid, and diagnosing the cause of the leak in the case of a leak. The present invention further relates to a device for detecting leaks during the process of filling a vehicle with a fluid and a vehicle production line.

Description

Technical Field

[0001] The present invention relates to a method for detecting leaks during the fluid filling process of a vehicle, a device for detecting leaks during the fluid filling process of a vehicle, and a vehicle production line including the device. Background Art

[0002] During the vehicle production process, filling fluids such as refrigerant, antifreeze, and brake fluid is an important step. Once a leak occurs during the filling process, it will affect production efficiency, increase repair time, and seriously affect the subsequent sales of the vehicle and the market reputation of the brand.

[0003] During the assembly process of the vehicle production line, a filling gun is used to fill the fluid into the fluid pipeline system of the vehicle, especially into the container kettle of the fluid pipeline system. Currently, in order to detect whether there is a leak in the fluid pipeline system, the injection volume of the filling fluid is monitored and compared with the standard injection volume. If the error between the injected volume and the standard injection volume is less than a predetermined threshold, there is no leak in the filling process. In addition, sensors (such as temperature sensors, pressure sensors, flow sensors, etc.) can be set on the filling gun side to assist in monitoring the filling process. A warning is issued in the event of a leak to promptly stop the filling process and repair the vehicle.

[0004] However, in the prior art process, the values of the sensors are read at predetermined successive moments based on the sensor data, the difference between the front and back is calculated, and it is judged whether there is a leak by comparing with the allowable error. Therefore, in the existing process, it is only possible to simply judge whether there is a leak during the filling process, but it is impossible to judge the cause of the leak. Therefore, maintenance personnel still need a long time to check one by one the fluid pipeline system of the vehicle and even the filling equipment.

[0005] Therefore, there is an urgent need for a method that can diagnose the cause of a leak during the fluid filling process of a vehicle. Summary of the Invention

[0006] The object of the present invention is to provide a method, a device for detecting leaks during the fluid filling process of a vehicle, and a vehicle production line, so that it is possible to accurately identify whether there is a leak during the fluid filling process, and to diagnose the cause of the leak in the event of a leak, thereby saving leak detection and repair time.

[0007] The first aspect of the present invention relates to a method for detecting leaks during the fluid filling process of a vehicle. The method includes a positive pressure process, a negative pressure process, and a filling process. During the positive pressure process, a high-pressure gas is filled into the fluid pipeline system of the vehicle, particularly the container kettle of the fluid pipeline system, through the fluid filling port of the vehicle via a filling gun. During the negative pressure process, the fluid pipeline system is evacuated, and during the filling process, fluid is filled.

[0008] It is characterized in that the method includes:

[0009] - By means of a sensor provided in the filling gun barrel, the change curves of the pressure over time during the positive pressure process and the negative pressure process are respectively collected at least during part of the time period.

[0010] - Based on the analysis of the characteristics of the collected change curves, it is judged whether there is a leak during the fluid filling process of the vehicle, and the cause of the leak is diagnosed in the case of a leak.

[0011] According to the present invention, the method includes a positive pressure process, a negative pressure process, and a filling process. During the positive pressure process, a high-pressure gas is filled into the fluid pipeline system of the vehicle, particularly the container kettle of the fluid pipeline system, through the fluid filling port of the vehicle via a filling gun. During this process, for example, the pressure in the filling gun barrel and / or in the fluid pipeline system being filled can be collected by a pressure sensor provided in the pipeline for injecting the high-pressure gas in the filling gun barrel, and the change curve of the pressure over time is recorded. Here, the curve characteristics are extracted, and the curve characteristics can include slope, amplitude, type and parameters of curve fitting, etc. The characteristics of the collected change curves are analyzed. For example, the extracted curve characteristics are compared with the characteristics of a standard curve without a leak. If the difference between the two is less than a predetermined threshold, it is judged that there is no leak during the fluid filling process of the vehicle. If there are significant differences between the extracted curve characteristics and the characteristics of the standard curve, the curve characteristics are respectively compared with the curve characteristics of known different types of leak curves, so as to diagnose the cause of the leak.

[0012] Preferably, immediately following the positive pressure process, the negative pressure process is carried out. During the negative pressure process, a vacuum is drawn on the fluid pipeline system of the vehicle, particularly the container pot of the fluid pipeline system, via a filling gun through the fluid filling port of the vehicle. Here, for example, the pressure inside the gun barrel can be detected by a pressure sensor provided in the pipeline for vacuum extraction in the filling gun barrel, and the variation curve of the pressure over time can be collected. The negative pressure process can particularly verify the leakage causes determined in the positive pressure process, thereby improving the accuracy rate of diagnosing the leakage type. In particular, it can be stipulated that the negative pressure process is carried out adjacent to the filling process. Since the fluid pipeline system has been evacuated during the negative pressure process, this helps the fluid to be injected into it, increases the filling speed and avoids gas occupancy after filling.

[0013] Finally, if no leakage is detected at the fluid filling port and the fluid pipeline system of the vehicle during both the positive pressure process and the negative pressure process, the filling process is carried out. During the filling process, the filling fluid is injected into the fluid pipeline system of the vehicle via the fluid filling port by means of a filling gun. In addition, during the filling process, the variation curve of the filling fluid volume can also be monitored and compared with the standard curve for the absence of leakage, so that the presence of leakage can be finally verified again.

[0014] According to the present invention, both the positive pressure process and the negative pressure process are carried out on the fluid pipeline system of the vehicle, so that it can be fully ensured that the airtightness and compressive strength of the fluid pipeline system to be filled meet the standards, thereby ensuring the quality of the vehicles leaving the factory.

[0015] It should be noted that compared with the prior art method of judging whether there is leakage in the link of filling the vehicle with fluid by the measured value of the sensor at a specific moment, the method according to the present invention collects in real time the variation curves of the measured values of the sensor over time during the positive pressure process and the negative pressure process. Different leakage causes are distinguished according to the different trends of the pressure variation curves, and it can be timely and accurately understood whether there is leakage during the filling process and the cause of the leakage can be judged. Thereby, it provides effective assistance and support not only for the on-site operators but also for the subsequent maintenance personnel, saves the time for cause investigation and maintenance, and improves the production efficiency of the filling link.

[0016] It should be noted that in the prior art, in the actual process of vehicle fluid filling, the steps are not carried out sequentially, but intersect with each other. Therefore, it is difficult to accurately read information from the data output by the sensor for analyzing the filling process, which results in opaque data and is difficult for the operator to interpret. According to the method of the present invention, the positive pressure process, the negative pressure process, and the filling process are carried out sequentially. By using the sensors provided on the filling gun barrel, especially the pressure sensor and / or the vacuum sensor, the pressure changes in the positive pressure process and the negative pressure process can be respectively collected to form separate pressure change curves, which can make the data of the filling link transparent and simplify the complexity of data analysis.

[0017] According to an implementation form of the present invention, with the thimble of the filling gun barrel closed, high-pressure gas is filled into the filling gun barrel during the positive pressure process to reach a predetermined positive pressure, and the pressure is maintained continuously, and / or the filling gun barrel is evacuated to reach a predetermined negative pressure during the negative pressure process, and the pressure is maintained continuously, and the change curve of the pressure in the filling gun barrel over time is collected. Here, the thimble is located at the outlet of the filling gun, which can control the discharge and suction of fluid (gas or liquid) from the filling gun. With the thimble of the filling gun barrel closed, the filling gun is not connected to the fluid filling port of the vehicle and the fluid pipeline system of the vehicle, and a separate gas space is formed in the filling gun. Here, high-pressure gas is filled into or the filling gun barrel is evacuated, and the pressure sensor provided in the filling gun barrel detects that the pressure reaches the predetermined positive pressure or negative pressure. Here, the predetermined positive pressure is, for example, P0 = 15 bar, and the predetermined negative pressure is, for example, P0' = 0.01 bar. After reaching the predetermined pressure value, the pressurization or evacuation is stopped, and the pressure is maintained continuously. The change curve of the pressure in the filling gun pipeline over time is collected during the pressure maintenance stage. If the change amount of the pressure of the filling gun exceeds a predetermined value within a predetermined time period after the start of pressure maintenance, it is determined that there is a leak in the filling gun barrel. In this case, the filling gun barrel needs to be repaired or replaced with a new one.

[0018] According to an implementation form of the present invention, during the positive pressure process, the fluid pipeline system is pre-filled with high-pressure gas up to a predetermined positive pressure and maintained at a constant pressure; and / or during the negative pressure process, the fluid pipeline system is pre-evacuated to a predetermined negative pressure and maintained at a constant pressure. When the thimble of the filling gun barrel is closed, during the positive pressure process, for example, the fluid pipeline system can be pre-filled with high-pressure gas so that the fluid pipeline system of the vehicle reaches the predetermined positive pressure, such as 15 bar. That is, when the thimble is closed, the pressure of the high-pressure gas filled in the filling gun barrel is the same as the positive pressure pre-filled in the fluid pipeline system, and after the fluid pipeline system reaches the predetermined positive pressure, the pressurization is stopped and the pressure is maintained. Similarly, during the negative pressure process, the negative pressure of the vacuum extraction in the filling gun barrel is the same as the negative pressure of the pre-evacuation of the fluid pipeline system, such as 0.01 bar, and after the fluid pipeline system reaches the predetermined negative pressure, the vacuum extraction is stopped and the pressure is maintained. During the positive pressure process and the negative pressure process, after reaching the predetermined pressure, for example, the pressure is maintained for several minutes to several hours. Preferably, during the positive pressure process, the pressure is maintained for two hours after reaching the predetermined positive pressure.

[0019] According to an implementation form of the present invention, it is judged whether there is a leak according to the amplitude fluctuation of the change curve before and after the thimble of the filling gun barrel is opened. After the end of the pressure maintenance stage, the thimble of the filling gun barrel is opened, and the filling gun barrel is communicated with the fluid filling port of the vehicle and the fluid pipeline system. It is judged whether there is a leak by observing the amplitude fluctuation of the curve within a period of time after the thimble is opened, such as within 2 s. If there is an amplitude fluctuation, this means that after the thimble is opened, the pressure in the fluid filling port of the vehicle and the fluid pipeline system is no longer consistent with the pressure in the filling gun barrel, so there is a pressure change during the pressure maintenance stage, which is caused by a leak between the fluid filling port of the vehicle and the fluid pipeline system. Here, if the amplitude fluctuation exceeds 550 mbar, for example, it is diagnosed that there is a leak in the fluid filling port of the vehicle and / or the fluid pipeline system.

[0020] According to an implementation form of the present invention, a curve segment from the moment when the thimble is opened until the moment when the exhaust valve is opened is intercepted, and the cause of the leak is diagnosed by performing regression analysis on the curve segment. The sensor provided in the filling gun barrel detects the pressure measurement value at a predetermined time interval. Here, the discrete measurement values obtained from the sensor are represented by a discrete point group (t, y), where t represents the measurement moment from the moment when the thimble is opened until the moment when the exhaust valve is opened, and y represents the measurement value of the sensor at time t. In order to fully reflect the change law of these measurement values over time, through the discrete point groups (t1, y1), (t2, y2)... (t m , y m)To establish a regression function y = f(t) between y and t to best approximate or fit a known set of discrete points.

[0021] According to an embodiment of the present invention, the cause of leakage is determined by the type of regression function of the regression of the curve segment. Here, for example, the least squares method is used to perform regression analysis on the set of discrete points. Based on the correlation coefficients obtained from regression analysis under different regression models, the regression function corresponding to the curve is specifically determined. The regression models can include, for example, a linear model and non-linear models such as an exponential model, a logarithmic model, a polynomial model, and the like.

[0022] According to an embodiment of the present invention, when the regression function is a linear function and especially when the slope of the regression function is less than a predetermined slope threshold, the cause of leakage is diagnosed as poor sealing at the connection position between the filling gun and the fluid filling port. When fitting the regression function y = f(t) to a linear function y = kt + b, the parameters k and b of the linear function are determined by minimizing the sum of the squared residuals between the measured values of the sensor and the amplitude of the regression function. Especially if the absolute value of the slope k of the regression function is less than the predetermined slope threshold, that is, the inclination angle of the regression function is less than the predetermined inclination angle threshold, the cause of leakage is diagnosed as poor sealing at the connection position between the filling gun and the fluid filling port. Here, for example, the inclination angle threshold of the regression function is specified as 30°, that is, the slope threshold is tan(30°) = 0.5778. In this case, since the leakage occurs at the connection position between the filling gun and the fluid filling port, that is, when the filling gun is connected to the fluid filling port, especially when the ejector pin is opened, a slight leakage occurs due to poor airtightness. Here, it can be considered that there is no leakage on the vehicle side, and the reason for the pressure drop may be that the sealing ring of the filling gun does not fully fit the filling port, the filling port is uneven, or the pressing force of the filling gun is insufficient.

[0023] According to an embodiment of the present invention, in the case where the regression function is an exponential function, the leakage position and degree are determined based on the exponential term coefficient and the constant term. The exponential function can be expressed as y = a + P0e xt. During the positive pressure process, the measured value of the sensor gradually decreases with the leakage process. In this case, x < 0. While during the negative pressure process, the measured value of the sensor gradually increases with the leakage process. In this case, x > 0. The absolute value of the exponential term coefficient can reflect the change rate of the exponential function. If there is a leakage on the vehicle side, then during the pressure holding stage, the pressure in the fluid filling port and the fluid pipeline system of the vehicle deviates from the pressure in the filling gun. After the thimble is opened, the change curve will first change rapidly, and then the change rate gradually decreases. The constant term a reflects the pressure value in the fluid filling port and the fluid pipeline system of the vehicle during the stage when the change rate decreases and the pressure change is relatively stable. Therefore, the leakage location and degree can be judged by the exponential term coefficient and the constant term.

[0024] According to an embodiment of the present invention, during the positive pressure process, when the constant term of the exponential function is lower than a predetermined positive pressure threshold, it is determined that the connection between the filling gun barrel and the fluid filling port fails or the fluid pipeline system is not pre-pressurized; and / or during the negative pressure process, when the constant term of the exponential function is higher than a predetermined negative pressure threshold, it is determined that the connection between the filling gun and the filling port fails or the fluid pipeline system is not pre-vacuumed. Here, during the positive pressure process, if the constant term of the exponential function is lower than a predetermined positive pressure threshold, such as lower than 12 bar, especially close to the atmospheric pressure, this indicates that the pressure of the communication chamber including the filling gun barrel, the fluid filling port and the fluid pipeline system of the vehicle detected by the sensor provided in the filling gun barrel significantly decreases between the moment when the thimble is opened and the moment when the exhaust valve is opened, which may be caused by the failure of the connection between the filling gun barrel and the fluid filling port or the fluid pipeline system not being pre-pressurized. During the negative pressure process, if the constant term of the exponential function is higher than a predetermined negative pressure threshold, such as higher than 0.3 bar, especially close to the atmospheric pressure, this may be caused by the failure of the connection between the filling gun barrel and the fluid filling port or the fluid pipeline system not being pre-vacuumed.

[0025] According to an implementation form of the present invention, when the absolute value of the exponential term coefficient is less than or equal to the first threshold, it is determined that there is a leak point in the distal pipeline of the fluid pipeline system; when the absolute value of the exponential term coefficient is greater than the first threshold, it is determined that there is a leak point in the container kettle of the fluid pipeline system. Herein, the first threshold is set to 0.015. When the absolute value of the exponential term coefficient is less than or equal to the first threshold, the pressure detected by the sensor changes slowly, which may be due to a small leakage amount and a long distance between the leakage position and the sensor, resulting in a slow pressure response. Herein, possible leakage reasons are, for example, that there are sand holes in the pipe wall of the pipeline in the fluid pipeline system of the vehicle, the plug at the end of the pipeline is not tightly plugged, the valve body in the pipeline is not sealed, etc. When the absolute value of the exponential term coefficient is greater than the first threshold, this may be due to a small leakage amount and a short distance between the leakage position and the sensor, resulting in a fast pressure response. Herein, possible leakage reasons are, for example, that there are sand holes in the wall of the container kettle of the fluid pipeline system, the plug of the container kettle is not tightly plugged, the interface between the container kettle and the pipeline of the fluid pipeline system is not sealed, etc.

[0026] According to an implementation form of the present invention, the leakage rate of the leak hole is calculated based on the regressed exponential function and the size of the leak hole is estimated. The leakage rate of the leak hole represents the gas volume of the gas flowing through the leak hole per unit time, that is where Q represents the leakage rate of the leak hole, and P represents the pressure of the current container. Herein, the pressure P of the current container can be calculated by using the regressed curve P = a + P0e xt V represents the volume of the current container, which can be approximately equal to the volume of the communication chamber including the filling gun barrel, the fluid filling port and the fluid pipeline system of the vehicle, and it is assumed that the volume remains unchanged during this time period. Thus, the leakage rate of the leak hole is specifically calculated by using the difference between the constant term of the regressed exponential function and the predetermined positive pressure / negative pressure, as well as the pressure holding time. Further, the size of the leak hole can also be estimated through the leakage rate of the leak hole. When the leakage rate is greater than 10 - 6 Pa·m 3 / s, the flow state of the gas in the leak hole can be regarded as the viscous flow state, and the corresponding leak hole diameter is greater than 5μm. When the leakage rate is less than 10 -9 Pa·m 3 / s, the flow state of the gas in the leak hole can be regarded as the molecular state, and the corresponding leak hole diameter is less than 1μm. Preferably, the temperature measured by the temperature sensor is used to perform temperature compensation on the calculation result during the calculation process to improve the accuracy of the calculation result. Herein, the corresponding fluid pipeline system is evaluated according to the calculated leakage rate of the leak hole and the estimated size of the leak hole, and effective data assistance is further provided to the operators and maintenance personnel.

[0027] The second aspect of the present invention relates to a device for detecting leakage during the fluid filling process of a vehicle, and the device includes:

[0028] - A filling gun that can fill high-pressure gas, evacuate, and fill fluid into the fluid pipeline system of a vehicle, particularly the container pot of the fluid pipeline system, via the fluid filling port of the vehicle during the positive pressure process, negative pressure process, and filling process respectively;

[0029] - A control device for controlling the filling gun to perform the positive pressure process, negative pressure process, and filling process;

[0030] It is characterized in that the equipment includes:

[0031] - A sensor disposed in the filling gun barrel and capable of collecting the curve of the pressure change in the filling gun barrel over time during the positive pressure process and negative pressure process;

[0032] - An analysis and diagnosis device that, based on the analysis of the characteristics of the collected change curve, determines whether there is a leak during the filling process and diagnoses the cause of the leak in the case of a leak.

[0033] Preferably, the method according to the present invention is implemented by means of the above-mentioned equipment.

[0034] According to an implementation form of the present invention, the fluid pipeline system of the vehicle at least includes a coolant pipeline system, a refrigerant pipeline system, an antifreeze pipeline system, a brake fluid pipeline system, a brake oil pipeline system, a power steering and hydraulic system oil pipeline system, a PAG oil pipeline system, an engine pipeline system, an axle pipeline system, a gearbox and differential oil pipeline system, a glass cleaner pipeline system, an aqueous urea solution pipeline system, a compressed air pipeline system, a test and synthesis gas pipeline system, a fuel pipeline system, a diesel additive pipeline system, etc.; and / or the filling fluid at least includes coolant (ethylene glycol), refrigerant (R134a, R744, R1234yf), antifreeze, brake fluid (DOT), brake oil, power steering and hydraulic system oil, PAG oil, engine oil, axle oil, gearbox oil and differential oil, glass cleaner, aqueous urea solution (Urea, AUS 32, DEF, SCR, ), (such as compressed air for air springs), (such as test and synthesis gas for leak testing), fuel (gasoline, diesel, ethanol), diesel additive ( DPX), etc.

[0035] The third aspect of the present invention relates to a vehicle production line that includes the equipment according to the present invention for detecting leaks during the fluid filling link of a vehicle.

[0036] It should be noted that the features, functions, effects, advantages, etc. according to one aspect of the present invention can also be referred to the above descriptions of other aspects of the present invention. In addition, the various aspects described in this document can be combined with each other diversely. The features disclosed in this application document are important and can be implemented not only individually but also in any combination for the implementation of the embodiments in terms of different design solutions. Description of the Drawings

[0037] Figure 1 A flowchart showing an embodiment of a method for detecting leaks during the fluid filling process of a vehicle;

[0038] Figure 2 A flowchart showing an embodiment of a method for detecting leaks during the positive pressure process;

[0039] Figure 3 An embodiment showing the diagnosis of the cause of a leak by performing a regression analysis on the pressure change curve during the positive pressure process;

[0040] Figure 4 An embodiment showing the diagnosis of the cause of a leak by performing a regression analysis on the pressure change curve during the positive pressure process;

[0041] Figure 5 An embodiment showing the diagnosis of the cause of a leak by performing a regression analysis on the pressure change curve during the positive pressure process;

[0042] Figure 6 An embodiment showing the diagnosis of the cause of a leak by performing a regression analysis on the pressure change curve during the positive pressure process;

[0043] Figure 7 A block diagram showing a device for detecting leaks during the fluid filling process of a vehicle. Detailed Embodiments

[0044] Figure 1 A flowchart showing an embodiment of a method for detecting leaks during the fluid filling process of a vehicle. The method includes a positive pressure process, a negative pressure process, and a filling process. During the positive pressure process, the negative pressure process, and the filling process, a high-pressure gas, a vacuum, and a fluid are respectively filled into the fluid pipeline system of the vehicle, particularly the container pot of the fluid pipeline system, through the fluid filling port of the vehicle by means of a filling gun.

[0045] The method includes:

[0046] - At least during some periods, respectively collect the curves of the pressure change over time during the positive pressure process and the negative pressure process through a sensor provided in the filling gun barrel;

[0047] - Based on the analysis of the characteristics of the collected change curves, it is determined whether there is a leak in the vehicle fluid filling process, and the cause of the leak is diagnosed in the case of a leak.

[0048] According to the method of the present invention, the positive pressure process, the negative pressure process, and the filling process are preferably carried out in sequence. By using sensors respectively arranged on the filling pipeline and the vacuum extraction pipeline, the pressure changes in the filling process and the negative pressure process can be collected respectively to form separate pressure change curves. By analyzing the curve characteristics of the change curves, it is possible to timely and accurately understand whether there is a leak in the vehicle fluid filling process, and it is possible to judge the cause of the leak. Therefore, corresponding maintenance measures can be taken in the case of a leak, saving maintenance time. Finally, if no leak is detected in the vehicle fluid filling port and the fluid pipeline system during the positive pressure process and the negative pressure process, the filling process is carried out.

[0049] Figure 2 A flowchart showing an embodiment of the method for detecting a leak during the positive pressure process is shown. First, the filling gun is connected to the vehicle fluid filling port, the thimble is closed, and during the positive pressure process, high-pressure gas is filled into the filling gun barrel to reach a predetermined positive pressure. Here, the predetermined positive pressure is, for example, P0 = 15 bar. After reaching the predetermined pressure value, the pressurization is stopped and the pressure is maintained continuously. During this period, the change curve of the pressure in the filling gun pipeline over time is collected. If the change amount of the pressure of the filling gun barrel exceeds a predetermined value, for example, 100 mbar, within a predetermined time period after the start of pressure maintenance, there is a leak in the filling gun barrel. In the case of a leak in the filling gun barrel, the filling gun barrel is repaired or a new filling gun barrel is replaced.

[0050] At the same time, the fluid pipeline system is pre-filled with high-pressure gas up to the predetermined positive pressure by another filling device and the pressure is maintained continuously. It is also conceivable that the pre-filling of the fluid pipeline system is carried out before or after filling the filling gun barrel with high-pressure gas, and the pressure of the high-pressure gas filled into the filling gun barrel is the same as the positive pressure pre-filled in the fluid pipeline system. In the current embodiment, after the pressure of the fluid pipeline system reaches P0 = 15 bar, the pressure is maintained. Then the thimble is opened, and the change curve of the pressure over time during the positive pressure process is collected by the sensor arranged in the filling gun barrel. Whether there is a leak is judged according to the amplitude fluctuation of the change curve before and after the thimble of the filling gun barrel is opened. In the current embodiment, if the amplitude fluctuation is less than 550 mbar, it is determined that there is no leak in the vehicle fluid filling port and the fluid pipeline system, and the vehicle is detected as qualified during the positive pressure process, and then the vehicle is subjected to subsequent negative pressure detection. If the amplitude fluctuation exceeds 550 mbar, it is diagnosed that there is a leak in the vehicle fluid filling port and the fluid pipeline system.

[0051] In the case of leakage in the fluid filling port of the vehicle and the fluid pipeline system, a curve segment from the moment when the thimble is opened until the moment when the exhaust valve is opened is intercepted, and the cause of the leakage is diagnosed by performing regression analysis on the curve segment. Preferably, the cause of the leakage is judged by the type of the regression function of the regression of the curve segment. If the regression function is a linear function and the slope of the regression function is less than a predetermined slope threshold, the cause of the leakage is diagnosed as poor sealing at the connection position between the filling gun and the fluid filling port. In the current embodiment, the inclination angle threshold of the regression function is specified as 30°, that is, the slope threshold is tan(30°) = 0.5778. If the slope of the linear function is less than 0.5778, it is determined that the leakage occurs at the connection position between the filling gun and the fluid filling port, and the leakage is only caused by a poor connection. Thus, it is judged that there is no leakage on the vehicle side, and then the vehicle is subjected to subsequent negative pressure detection.

[0052] In the case where the regression function is an exponential function, the leakage position and degree are judged based on the judgment of the exponential term coefficient and the constant term. When the constant term of the exponential function is lower than a predetermined positive pressure threshold, it is judged that the connection between the filling gun barrel and the fluid filling port fails or the fluid pipeline system is not pre-pressurized. In the current embodiment, if the constant term of the exponential function is lower than 12 bar, especially close to the atmospheric pressure, this indicates that the pressure of the communication chamber including the filling gun barrel, the fluid filling port and the fluid pipeline system of the vehicle detected by the sensor provided in the filling gun barrel significantly decreases between the moment when the thimble is opened until the moment when the exhaust valve is opened, which may be caused by the failure of the connection between the filling gun barrel and the fluid filling port or the fluid pipeline system not being pre-pressurized. Thus, it is judged that there may be no leakage on the vehicle side and the vehicle can then be subjected to subsequent negative pressure detection.

[0053] If the constant term of the exponential function is not lower than a predetermined positive pressure threshold, then a judgment is made based on the coefficient of the exponential term of the exponential function. When the absolute value of the coefficient of the exponential term is less than or equal to the first threshold, it is determined that there is a leak in the distal pipeline in the fluid pipeline system. In the current embodiment, the first threshold is set to 0.015. When the absolute value of the coefficient of the exponential term is less than or equal to the first threshold, the pressure detected by the sensor changes slowly, which may be due to a small leakage amount and a long distance between the leakage position and the sensor, resulting in a slow pressure response. Here, possible leakage reasons are, for example, that there are sand holes in the pipe wall of the pipeline in the fluid pipeline system, the end plug of the pipeline is not tightly plugged, the valve body in the pipeline is not sealed, etc. When the absolute value of the coefficient of the exponential term is greater than the first threshold, this may be due to a small leakage amount and a short distance between the leakage position and the sensor, resulting in a fast pressure response. Here, possible leakage reasons are, for example, that there are sand holes in the wall of the container pot in the fluid pipeline system, the plug of the container pot is not tightly plugged, the interface between the container pot and the pipeline of the fluid pipeline system is not sealed, etc. In this case, since there is a leak on the vehicle side, the vehicle needs to be repaired offline or the tail line equipment needs to be supplemented. Preferably, the leak rate of the leak hole is calculated based on the regressed exponential function and the size of the leak hole is estimated.

[0054] Figure 3 An embodiment of diagnosing the leakage cause by performing regression analysis on the pressure change curve during the positive pressure process is shown. Here, the abscissa represents time and the ordinate represents the measured value in the sensor provided in the filling gun barrel. In the current implementation, the thimble is opened at time t1 and the exhaust valve is opened at time t2. The curve segment from the thimble opening time t1 until the exhaust valve opening time t2 is intercepted. Within this curve segment, the regression function can be fitted with a linear function y = kt + b. The slope of the regression function within this curve segment is calculated as This slope is less than the predetermined slope threshold of 0.5778. Therefore, in this embodiment, it can be diagnosed that the leakage occurs at the connection position between the filling gun and the fluid filling port.

[0055] Figure 4 An embodiment of diagnosing the leakage cause by performing regression analysis on the pressure change curve during the positive pressure process is shown. In the current embodiment, within the curve segment from the thimble opening time t1 until the exhaust valve opening time t2, the regression function can be fitted with an exponential function y = a + P0e xt First, the constant term a of the exponential function is compared with the predetermined positive pressure threshold. Here, the measured value of the sensor drops rapidly from the thimble opening time t1 and has approached the atmospheric pressure before the exhaust valve opening time t2. At this time, a ≈ 1, and this constant term is less than the predetermined positive pressure threshold of 12 bar. Therefore, in this implementation, it can be diagnosed that the leakage is due to the failure of the connection between the filling gun barrel and the fluid filling port or the fluid pipeline system not being pre-pressurized.

[0056] Figure 5 An embodiment of diagnosing the leakage cause by performing regression analysis on the pressure change curve during the positive pressure process is shown. In the current embodiment, within the curve segment from the moment t1 when the thimble is opened to the moment t2 when the exhaust valve is opened, the exponential function y = a + P0e xt can be used to fit the regression function. The measured value of the sensor starts to slowly decrease after dropping close to P t3 = 12.5 bar. Thus, the constant term a ≈ 12.5 bar is greater than the predetermined positive pressure threshold of 12 bar. Calculate the coefficient of the exponential term Here, the absolute value of the coefficient of the exponential term is less than or equal to the first threshold of 0.015. Therefore, it is determined that there is a leak point in the distal pipeline of the fluid pipeline system. This may be due to a small leakage amount and the leakage position being far from the sensor, resulting in a slow pressure response. Here, possible leakage causes include, for example, the presence of sand holes in the pipe wall of the pipeline in the fluid pipeline system, the plug at the end of the pipeline not being tightly plugged, the valve body in the pipeline not being airtight, etc.

[0057] Figure 6 An embodiment of diagnosing the leakage cause by performing regression analysis on the pressure change curve during the positive pressure process is shown. In the current embodiment, within the curve segment from the moment t1 when the thimble is opened to the moment t2 when the exhaust valve is opened, the exponential function y = a + P0e xt can be used to fit the regression function. The measured value of the sensor starts to slowly decrease after dropping close to P t3 = 14 bar. Thus, the constant term a ≈ 14 bar is greater than the predetermined positive pressure threshold of 12 bar. Calculate the coefficient of the exponential term Here, the absolute value of the coefficient of the exponential term is greater than the first threshold of 0.015. Therefore, it is determined that there is a leak point in the container pot of the fluid pipeline system. This may be due to a relatively small leakage amount and the leakage position being relatively close to the sensor, resulting in a fast pressure response. Here, possible leakage causes include, for example, the presence of sand holes in the wall of the container pot of the fluid pipeline system, the plug of the container pot not being tightly plugged, the interface between the container pot and the pipeline of the fluid pipeline system not being sealed, etc.

[0058] Figure 7 An apparatus 1 for detecting leakage during the process of filling a vehicle with fluid is shown. The apparatus 1 includes:

[0059] - A filling gun that can fill high-pressure gas, evacuate, and fill fluid into the vehicle's fluid pipeline system, particularly the container pot of the fluid pipeline system, via the vehicle's fluid filling port during the positive pressure process, negative pressure process, and filling process respectively; -

[0060] - A control device for controlling the filling gun to perform the positive pressure process, the negative pressure process, and the filling process;

[0061] - A sensor, which is arranged in the filling gun barrel and can collect the curve of the change of the pressure in the filling gun barrel over time during the positive pressure process and the negative pressure process;

[0062] - An analysis and diagnosis device, which judges whether there is a leak during the filling process based on the analysis of the characteristics of the collected change curve, and diagnoses the cause of the leak in case of a leak.

[0063] Preferably, the device is arranged to implement the method according to the present invention.

[0064] Although the present invention has been disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the disclosed methods and technical contents without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change and decoration made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention all belong to the protection scope of the technical solution of the present invention.

Claims

1. A method for detecting leaks during the fluid filling process of a vehicle, characterized in that, The method includes a positive pressure process, a negative pressure process, and a filling process. During the positive pressure process, the negative pressure process, and the filling process, a high-pressure gas, a vacuum, and a fluid are respectively filled into the fluid pipeline system of the vehicle through the fluid filling port of the vehicle by means of a filling gun. The positive pressure process, the negative pressure process, and the filling process are carried out in sequence. Wherein, the method includes: - At least during some periods, respectively collect the curves of the pressure change with time during the positive pressure process and the negative pressure process through a sensor provided in the filling gun barrel; - Extract the curve features of the curves of the pressure change with time during the positive pressure process and the negative pressure process. The curve features include slope, amplitude, and / or the type and parameters of curve fitting; - Based on the analysis of the features of the collected change curves, judge whether there is a leak in the link of filling the fluid into the vehicle, and diagnose the cause of the leak in the case of a leak. Compare the extracted curve features with the features of the standard curve without a leak. If the difference between the two is less than a predetermined threshold, it is judged that there is no leak in the link of filling the fluid into the vehicle. Compare the curve features with the curve features of known different types of leak curves respectively to diagnose the cause of the leak, and the negative pressure process can verify the cause of the leak determined in the positive pressure process.

2. The method according to claim 1, wherein When the thimble of the filling gun barrel is closed, a high-pressure gas is filled into the filling gun barrel during the positive pressure process to reach a predetermined positive pressure, and the pressure is maintained continuously; and / or during the negative pressure process, the filling gun barrel is evacuated to reach a predetermined negative pressure, and the pressure is maintained continuously, and the curve of the pressure change with time in the filling gun barrel is collected.

3. The method according to claim 2, wherein During the positive pressure process, the fluid pipeline system is pre-filled with a high-pressure gas to reach the predetermined positive pressure, and the pressure is maintained continuously; and / or During the negative pressure process, the fluid pipeline system is pre-evacuated to reach the predetermined negative pressure, and the pressure is maintained continuously.

4. The method according to claim 3, wherein Judge whether there is a leak according to the amplitude fluctuation of the change curve before and after the thimble of the filling gun barrel is opened.

5. The method according to claim 3 or 4, characterized in that, Intercept the curve segment from the moment when the thimble is opened until the moment when the exhaust valve is opened, and diagnose the cause of the leak by performing regression analysis on the curve segment.

6. The method according to claim 5, wherein Judge the cause of the leak through the type of the regression function of the regression of the curve segment.

7. The method according to claim 6, characterized in that When the regression function is a linear function, diagnose the cause of the leak as poor sealing at the connection position between the filling gun and the fluid filling port.

8. The method according to claim 6 or 7, characterized in that, When the regression function is an exponential function, judge the leak position and degree based on the exponential term coefficient and the constant term.

9. The method according to claim 8, characterized in that, During the positive pressure process, when the constant term of the exponential function is lower than the predetermined positive pressure threshold, judge that the connection between the filling gun barrel and the fluid filling port fails or the fluid pipeline system is not pre-pressurized; and / or during the negative pressure process, when the constant term of the exponential function is higher than the predetermined negative pressure threshold, judge that the connection between the filling gun barrel and the fluid filling port fails or the fluid pipeline system is not pre-evacuated.

10. The method according to claim 8, characterized in that When the absolute value of the coefficient of the exponential term is less than or equal to the first threshold, it is determined that there is a leak in the distal pipeline of the fluid pipeline system; When the absolute value of the coefficient of the exponential term is greater than the first threshold, it is determined that there is a leak in the container kettle in the fluid pipeline system.

11. The method according to claim 8, wherein, Calculate the leak rate of the leak hole and estimate the size of the leak hole based on the regressed exponential function.

12. The method according to any one of claims 1 to 4, characterized in that During the positive pressure process, the negative pressure process, and the filling process, high-pressure gas, vacuum, and fluid are respectively filled into the container kettle of the fluid pipeline system through the fluid filling port of the vehicle.

13. The method according to claim 7, wherein When the slope of the regression function is less than the predetermined slope threshold, the cause of the leakage is diagnosed as poor sealing at the connection position between the filling gun and the fluid filling port.

14. An apparatus for detecting leaks during the fluid filling process of a vehicle, characterized in that, Implement the method according to any one of claims 1 to 13 by means of the device, the device comprising: - A filling gun that can fill high-pressure gas, vacuum, and fluid into the fluid pipeline system of the vehicle through the fluid filling port of the vehicle during the positive pressure process, the negative pressure process, and the filling process respectively; - A control device for controlling the filling gun to implement the positive pressure process, the negative pressure process, and the filling process, wherein the positive pressure process, the negative pressure process, and the filling process are carried out in sequence; Wherein, the device comprises: - A sensor disposed in the filling gun barrel and capable of collecting the curve of the pressure change in the filling gun barrel over time during the positive pressure process and the negative pressure process; - An analysis and diagnosis device that determines whether there is a leak during the filling process based on the analysis of the characteristics of the collected change curve, and diagnoses the cause of the leak in the case of a leak.

15. The device according to claim 14, characterized in that, The fluid pipeline system of the vehicle at least includes: a coolant pipeline system, a refrigerant pipeline system, an antifreeze pipeline system, a brake fluid pipeline system, a brake fluid pipeline system, a power steering and hydraulic system oil pipeline system, a PAG oil pipeline system, an engine pipeline system, an axle pipeline system, a gearbox and differential oil pipeline system, a glass cleaner pipeline system, an aqueous urea solution pipeline system, a compressed air pipeline system, a test and synthesis gas pipeline system, a fuel pipeline system, a diesel additive pipeline system; and / or The filling fluid at least includes: coolant, refrigerant, antifreeze, brake fluid, brake fluid, power steering and hydraulic system oil, PAG oil, engine oil, axle oil, gearbox oil and differential oil, glass cleaner, aqueous urea solution, compressed air, test and synthesis gas, fuel, diesel additive.

16. A vehicle production line, comprising the device for detecting leaks in the link of filling fluid into the vehicle according to claim 14 or 15.

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