Method for detecting leakage of refrigerant for vehicle

Abstract

The present application relates to the technical field of refrigeration systems, and specifically provides a vehicle refrigerant leakage detection method, aiming to solve the problem of inaccurate refrigerant leakage detection results in the vehicle refrigeration system in the prior art. To this end, the detection method of the present application excludes the existence of refrigeration system component level faults or system faults by obtaining relevant parameters, uses a digital twin model to output simulated operating characteristic parameters, further decouples the attenuation factor of key components when there is a difference between the output results and the existing operating characteristics of the system, calibrates the digital twin model, uses the calibrated model to perform characteristic parameter operation again, and if there is still a difference, it is judged as refrigerant leakage. This method uses the flexible modeling characteristics of digital twins, is compatible with all configured and designed refrigerant systems, can match the vehicle state and operating environment in real time, and introduces the component attenuation factor to avoid the influence of component level performance degradation on the diagnosis result, so that the detection result is more accurate.

Description

Technical Field

[0001] This invention relates to the field of refrigeration system technology, and specifically provides a method for detecting refrigerant leaks in vehicles. Background Technology

[0002] As society develops and vehicle ownership continues to grow, people are increasingly focusing on vehicle comfort in addition to performance. The vehicle's cooling system, as a crucial component, significantly impacts comfort; therefore, effective testing of vehicle cooling systems is essential to enhance the user experience.

[0003] Refrigerant leakage in vehicles is one of the most common causes of refrigeration system failure or performance degradation. Current technologies mostly rely on comparing the operating status of components with predetermined values, which makes it difficult to account for the impact of environmental changes or component degradation on the detection results. For example, patent application number 2017103964430 describes a refrigerant leakage protection method that uses the electrical parameters of the compressor to detect refrigerant leakage. However, automotive compressors experience rapid performance degradation, making it difficult to isolate the impact of unhealthy compressor conditions on the detection results. Another example is patent application number 2016103082337, which describes a refrigerant leakage detection method and air conditioning device that uses coil temperature, indoor temperature, and low-pressure parameters for judgment. This method can only detect system performance degradation. In automotive scenarios with drastic changes in sunlight and fresh air load, or when other system or component failures cause poor cabin cooling performance, misjudgments may occur.

[0004] Accordingly, there is a need in the field for a new method for detecting refrigerant leaks in vehicles to address the aforementioned problems. Summary of the Invention

[0005] This invention aims to solve the aforementioned technical problem, namely, the inaccurate detection results in refrigerant leakage detection in automotive refrigeration systems in the prior art. To this end, this invention provides a method for detecting refrigerant leakage in automotive applications, which includes the following steps:

[0006] Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands; use the refrigeration system twin model to calculate and output simulated characteristic parameters; and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold.

[0007] If the first threshold is not reached, the test ends to confirm that there is no refrigerant leakage in the system; if the first threshold is reached, the attenuation factor of the terminal component is decoupled according to the operating parameters of the refrigeration system, the attenuation factor of the terminal component is substituted into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters, and it is determined whether the difference between the corrected simulation characteristic parameters and the actual characteristic parameters reaches the second threshold.

[0008] If the second threshold is not reached, it is determined that there is no refrigerant leak in the system; if the second threshold is reached, it is determined that there is a refrigerant leak in the system.

[0009] In the specific implementation of the above-mentioned method for detecting refrigerant leaks in vehicles, the step "decoupling the attenuation factor of the terminal component based on the operating parameters of the refrigeration system" specifically includes:

[0010] Based on the refrigeration system operating parameters, decouple at least one of the following: compressor efficiency attenuation factor, valve flow attenuation factor, high-pressure heat transfer attenuation factor, and low-pressure heat transfer attenuation factor.

[0011] In the specific implementation of the above-mentioned method for detecting refrigerant leaks in vehicles, the isentropic efficiency of the compressor is calculated based on the feedback values ​​of the high and low pressure temperature and pressure sensors at the compressor's suction and discharge ports and the compressor's feedback power. This is then compared with the initial isentropic efficiency in the twin model to obtain the compressor efficiency decay factor.

[0012] In the specific implementation of the above-mentioned method for detecting refrigerant leaks in vehicles, the valve flow rate attenuation factor is calculated based on the refrigerant flow rate output by the twin model of the refrigeration system.

[0013] In the specific implementation of the above-mentioned refrigerant leak detection method, the high-pressure heat transfer attenuation factor is calculated based on the system high pressure, ambient temperature, refrigerant flow rate, and PWM feedback value of the condenser fan.

[0014] In the specific implementation of the above-mentioned method for detecting refrigerant leaks in vehicles, the low-pressure heat transfer attenuation factor is calculated based on the system low pressure, HVAC intake air temperature and humidity, and blower airflow.

[0015] In the specific embodiments of the above-described method for detecting refrigerant leaks in vehicles, the environmental parameters include at least one of sunlight, ambient temperature and humidity, and cabin temperature and humidity; and / or

[0016] The refrigeration system setting parameters include at least one of the following: set temperature, air volume setting, internal / external circulation setting, and cooling / heating setting; and / or

[0017] The vehicle operating parameters include vehicle speed; and / or

[0018] The system terminal component control commands include at least one of the following: compressor speed command, valve opening degree command, valve opening degree command, fan PWM command, fresh air damper opening degree command, and mixing air damper opening degree command.

[0019] In the specific implementation of the above-mentioned method for detecting refrigerant leaks in vehicles, the step "using a twin model of the refrigeration system to calculate and output simulated characteristic parameters, and determining whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold" specifically means:

[0020] The outlet air temperature of the simulated evaporator cooling mode is calculated and output using a twin model of the refrigeration system. The difference between the simulated outlet air temperature and the actual outlet air temperature is compared to see if it is greater than 5°C and lasts for 5 minutes.

[0021] In the specific embodiment of the above-described method for detecting refrigerant leaks in vehicles, after the step of "decoupling the attenuation factor of the terminal component based on the operating parameters of the refrigeration system", the detection method further includes:

[0022] Compare whether the attenuation factor of the terminal component is greater than a set percentage. If it is greater than the set percentage, it is determined that there is an attenuation fault in the terminal component; if it is not greater than the set percentage, it is determined that there is no attenuation fault in the terminal component.

[0023] In the specific implementation of the above-mentioned method for detecting refrigerant leaks in vehicles, the step "acquiring at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands, calculating and outputting simulated characteristic parameters using a refrigeration system twin model, and determining whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold" is further defined as follows:

[0024] Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands, and determine whether there is a refrigeration system component-level fault or a system-level fault.

[0025] If a component-level or system-level fault exists, the test ends; if no component-level or system-level fault exists, the refrigeration system twin model is used to calculate and output simulated characteristic parameters to determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold.

[0026] In the specific embodiments of the above-described automotive refrigerant leak detection method, the component-level fault includes at least one of the following: compressor shutdown, valve shutdown, fan degradation or shutdown, and refrigerant temperature and pressure sensor failure; and / or

[0027] The system-level faults include congestion.

[0028] Solution 1. A method for detecting refrigerant leakage in vehicles, characterized in that the detection method includes the following steps:

[0029] Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands; use the refrigeration system twin model to calculate and output simulated characteristic parameters; and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold.

[0030] If the first threshold is not reached, the test ends to confirm that there is no refrigerant leakage in the system; if the first threshold is reached, the attenuation factor of the terminal component is decoupled according to the operating parameters of the refrigeration system, the attenuation factor of the terminal component is substituted into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters, and it is determined whether the difference between the corrected simulation characteristic parameters and the actual characteristic parameters reaches the second threshold.

[0031] If the second threshold is not reached, it is determined that there is no refrigerant leak in the system; if the second threshold is reached, it is determined that there is a refrigerant leak in the system.

[0032] Option 2. The automotive refrigerant leakage detection method according to Option 1, characterized in that the step "decoupling the attenuation factor of the terminal component based on the operating parameters of the refrigeration system" specifically includes:

[0033] Based on the refrigeration system operating parameters, decouple at least one of the following: compressor efficiency attenuation factor, valve flow attenuation factor, high-pressure heat transfer attenuation factor, and low-pressure heat transfer attenuation factor.

[0034] Scheme 3. The automotive refrigerant leakage detection method according to Scheme 2 is characterized in that, based on the feedback values ​​of the high and low pressure temperature and pressure sensors at the compressor's suction port and discharge port and the compressor's feedback power, the compressor's isentropic efficiency is calculated and compared with the initial isentropic efficiency in the twin model to obtain the compressor efficiency decay factor.

[0035] Scheme 4. The automotive refrigerant leakage detection method according to Scheme 2 is characterized in that the valve flow rate attenuation factor is calculated based on the refrigerant flow rate output by the twin model of the refrigeration system.

[0036] Scheme 5. The automotive refrigerant leakage detection method according to Scheme 2 is characterized in that the high-pressure heat transfer attenuation factor is calculated based on the system high pressure, ambient temperature, refrigerant flow rate and PWM feedback value of the condenser fan.

[0037] Scheme 6. The automotive refrigerant leakage detection method according to Scheme 2 is characterized in that the low-pressure heat transfer attenuation factor is calculated based on the system low pressure, HVAC intake air temperature and humidity, and blower air volume.

[0038] Option 7. A method for detecting refrigerant leaks in vehicles according to any one of Options 1 to 6, characterized in that the environmental parameters include at least one of sunlight, ambient temperature and humidity, and cabin temperature and humidity; and / or

[0039] The refrigeration system setting parameters include at least one of the following: set temperature, air volume setting, internal / external circulation setting, and cooling / heating setting; and / or

[0040] The vehicle operating parameters include vehicle speed; and / or

[0041] The system terminal component control commands include at least one of the following: compressor speed command, valve opening degree command, valve opening degree command, fan PWM command, fresh air damper opening degree command, and mixing air damper opening degree command.

[0042] Scheme 8. The automotive refrigerant leakage detection method according to any one of Schemes 1 to 7, characterized in that the step "using a twin model of the refrigeration system to calculate and output simulated characteristic parameters, and determining whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold" specifically comprises:

[0043] The outlet air temperature of the simulated evaporator cooling mode is calculated and output using a twin model of the refrigeration system. The difference between the simulated outlet air temperature and the actual outlet air temperature is compared to see if it is greater than 5°C and lasts for 5 minutes.

[0044] Scheme 9. A method for detecting refrigerant leakage in vehicles according to any one of Schemes 1 to 8, characterized in that, after the step of "decoupling the attenuation factor of the terminal component based on the operating parameters of the refrigeration system", the detection method further includes:

[0045] Compare whether the attenuation factor of the terminal component is greater than a set percentage. If it is greater than the set percentage, it is determined that there is an attenuation fault in the terminal component; if it is not greater than the set percentage, it is determined that there is no attenuation fault in the terminal component.

[0046] Scheme 10. The automotive refrigerant leakage detection method according to any one of Schemes 1 to 9, characterized in that the step of "acquiring at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands, calculating and outputting simulated characteristic parameters using a refrigeration system twin model, and determining whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold" is further defined as follows:

[0047] Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands, and determine whether there is a refrigeration system component-level fault or a system-level fault.

[0048] If a component-level or system-level fault exists, the test ends; if no component-level or system-level fault exists, the refrigeration system twin model is used to calculate and output simulated characteristic parameters to determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold.

[0049] Option 11. The automotive refrigerant leak detection method according to Option 10, characterized in that the component-level fault includes at least one of compressor shutdown, valve shutdown, fan degradation or shutdown, and refrigerant temperature and pressure sensor fault; and / or

[0050] The system-level faults include congestion.

[0051] By adopting the above technical solution, this invention can eliminate component-level or system-level faults in the vehicle itself by acquiring vehicle parameters. Using digital twins as a diagnostic tool, it outputs operating characteristic parameters in real time through a calibrated digital twin model of the refrigerant system. When there are differences between the output results and the existing operating characteristics of the system, the attenuation factors of key components are further decoupled to calibrate the digital twin model. The characteristic parameters are calculated again using the calibrated model. If there are still differences, it is judged to be a refrigerant leak, thereby improving the accuracy of refrigerant detection in automotive refrigeration systems. This method utilizes the flexible modeling characteristics of digital twins, is compatible with all configurations and designs of refrigerant systems, and can match vehicle status and operating environment in real time. At the same time, it introduces component attenuation factors to avoid the impact of component-level performance degradation on diagnostic results. After calculation, component attenuation faults and refrigerant leakage faults can be output simultaneously. Attached Figure Description

[0052] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0053] Figure 1 This is a schematic diagram of the main steps of the detection method in this invention;

[0054] Figure 2 This is a layout diagram of an automotive air conditioning system according to one embodiment of the present invention;

[0055] Figure 3 This is a diagram illustrating the threshold determination criteria in one embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram of one embodiment of the detection method in this invention, showing the steps for determining vehicle component-level or system-level faults;

[0057] Figure 5 This is a schematic diagram of one embodiment of the detection method in this invention, showing the steps for determining the degradation performance of vehicle components.

[0058] In the diagram: 1. External condenser, 2. First valve group, 3. Second valve group, 4. Third valve group, 5. Fourth valve group, 6. Fifth valve group, 7. Sixth valve group, 8. Internal condenser, 9. Evaporator, 10. Battery cooler, 11. Compressor, 12. High pressure temperature and pressure sensor, 13. Low pressure temperature and pressure sensor. Detailed Implementation

[0059] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings and in conjunction with an automotive air conditioning refrigeration system. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the invention and are not intended to limit the scope of protection of the invention. Those skilled in the art can make adjustments as needed to adapt to specific applications. For example, although the specification describes the invention in conjunction with an automotive air conditioning refrigeration system, this is not limiting. Those skilled in the art can apply the invention to any other refrigeration system as needed, as long as the refrigeration system requires the detection of refrigerant leakage, even if component degradation affects the accuracy of the detection results.

[0060] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] Furthermore, in order to more clearly demonstrate the core technical solution of the present invention, the description of the known structure of the vehicle air conditioning system is omitted in the following description. However, this omission is only for the convenience of description and does not mean that the vehicle air conditioning system can be without these structures.

[0062] like Figure 1 As shown, this invention proposes a method for detecting refrigerant leaks in vehicles, which includes the following steps:

[0063] S100: Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands; use the refrigeration system twin model to calculate and output simulated characteristic parameters;

[0064] S200: Determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold;

[0065] S210: If the first threshold is not reached, the test ends and it is confirmed that there is no refrigerant leakage in the system;

[0066] S220: If the first threshold is reached, the attenuation factor of the terminal component is decoupled according to the operating parameters of the refrigeration system, the attenuation factor of the terminal component is substituted into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters.

[0067] S300: Determine whether the difference between the corrected simulated characteristic parameters and the actual characteristic parameters reaches the second threshold;

[0068] S310: If the second threshold is not reached, it is determined that there is no refrigerant leak in the system;

[0069] S320: If the second threshold is reached, a refrigerant leak in the system is determined.

[0070] In this embodiment, by using a digital twin model of the refrigeration system, the parameters are obtained and then input into the digital twin model to obtain simulated characteristic parameters, which are used to make a preliminary judgment on whether there is a refrigerant leak in the refrigeration system. Then, in order to make the detection results more accurate and avoid the impact of the performance degradation of the refrigeration system components on the detection results, the degradation factor of the refrigeration system components is decoupled, the digital twin model of the refrigeration system is corrected, and the parameters are substituted into the model again for calculation and output of simulated characteristic parameters. These simulated characteristic parameters are compared with the actual characteristic parameters to obtain a final accurate conclusion.

[0071] It should be noted that in the above embodiments, the digital twin model of the refrigeration system is based on physical principles, mathematics, and computer modeling to digitally construct a model of the real refrigeration system. By substituting the operating environment and control commands of the actual refrigeration system into the twin model in digital form, the twin model can simulate the operation of the refrigeration system to obtain simulated characteristic parameters, which facilitates comparison with the actual operating parameters of the refrigeration system. In addition, the digital twin model of the refrigeration system can be adjusted accordingly based on the performance parameter decay of the terminal components, thereby maintaining consistency with the vehicle refrigeration system.

[0072] The digital information required for the aforementioned twin model can be obtained through sensors, monitoring equipment, computer software, and other means. The parameters required for the initial detection may vary in certain detection scenarios, but this does not affect the scope of protection of this invention. In other words, without departing from the technical concept of this invention, embodiments that obtain other relevant parameters and use digital twin models to eliminate the attenuation effect and thus improve the accuracy of detection results should also fall within the scope of protection of this invention.

[0073] Based on the above embodiments, see Figure 2The vehicle's air conditioning system operates in cooling mode. The arrows indicate the direction of refrigerant flow. This invention is described in conjunction with the vehicle's air conditioning system. Environmental parameters are collected, including but not limited to sunlight, ambient temperature and humidity, and the temperature and humidity inside the vehicle. Air conditioning setting parameters are collected, including but not limited to the set temperature, airflow, internal / external circulation settings, and cooling or heating mode settings. Vehicle operating parameters are collected, such as vehicle speed. Control commands for the refrigeration system's terminal components are collected, including but not limited to compressor speed commands, valve opening / closing degree commands, valve opening degree commands, fan PWM commands, fresh air damper opening degree, and mixing air damper opening degree commands. The collected parameters can be adaptively adjusted based on the parameters calculated using the digital twin model of the refrigeration system. After substituting the parameters into the twin model, the refrigeration system is simulated, and simulated characteristic parameters are output. In this embodiment, the evaporator outlet temperature in the evaporator cooling mode is compared to determine if there is a refrigerant leak. Therefore, the simulated characteristic parameter is the simulated evaporator outlet temperature. It should be noted that other characteristic parameters can be selected when testing other refrigeration systems. The simulated values ​​are compared with the actual values ​​of the vehicle to preliminarily determine if there is a refrigerant leak.

[0074] The comparison between the simulated evaporator outlet temperature and the actual evaporator outlet temperature uses a first threshold and a second threshold. The first threshold can be set to be the same or different depending on the test requirements. In this embodiment, it is set to whether the temperature difference between the simulated evaporator outlet temperature and the actual evaporator outlet temperature is greater than 5°C and lasts for 5 minutes. It should be noted that the first threshold and the second threshold are used to judge specific situations and need to be adjusted accordingly based on the specific situation of the target being tested.

[0075] The basis for adopting the above threshold in this embodiment is as follows, please refer to [link / reference]. Figure 2 and Figure 3 The operating system adopts Figure 2 The air conditioning system shown was operated in cooling mode, and it was confirmed that the performance of each component was not degraded. The relevant test parameters were as follows: ambient temperature: 30℃, RH 52%, no sunlight; vehicle speed: idle; air conditioning settings: temperature 23℃, fan speed automatic, internal and external circulation automatic.

[0076] The initial charge was 300g, then 100g was added each time until the minimum nominal charge was 700g. At 300g, the actual temperature difference between the outlet and theoretical outlet air was approximately 25℃; at 400g, the difference was 20℃; and at 500g and 600g, the difference was approximately 10℃. Upon reaching the nominal charge, the temperature difference test result was -2℃. Considering the expectation of detecting refrigerant leakage within 100g, a temperature difference of 5℃ was set to determine refrigerant leakage. Simultaneously, considering that the system is transient and unstable during the initial 100s of compressor operation, the error in the twin model calculations might be slightly larger at this time; therefore, a temperature difference duration of 5 minutes was set to avoid misjudgment.

[0077] Based on the above, when the simulated evaporator outlet temperature and the actual evaporator outlet temperature are within the first threshold, it can be determined that there is no refrigerant leakage. When the temperature exceeds the first threshold, it is necessary to decouple the attenuation factors. The attenuation factors of each component of the air conditioning system are obtained through system calculation. In this embodiment, the compressor efficiency attenuation factor, valve flow attenuation factor, high-pressure heat transfer attenuation factor, and low-pressure heat transfer attenuation factor are obtained. The refrigeration system twin model contains twin models of other components. For example, the valve flow attenuation factor can be calculated through the compressor twin model and the valve twin model. The system high pressure and system low pressure are obtained by the high-pressure temperature and pressure sensor and the low-pressure temperature and pressure sensor, respectively, and participate in the calculation of the corresponding attenuation factors. After obtaining the attenuation factors of each component, the refrigeration system digital twin model is corrected, and then substituted into the model to obtain the second simulated evaporator outlet temperature. If it does not exceed the second threshold at this time, it means that the evaporator outlet temperature is difficult to reach the standard due to component performance degradation, and it is not a refrigerant leak. However, if it still exceeds the second threshold at this time, it can be determined that there is a refrigerant leak in the refrigeration system.

[0078] Furthermore, such as Figure 4 As shown, the detection method includes the following steps:

[0079] S100: Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands;

[0080] S200: Determine if there is a component-level or system-level fault in the refrigeration system;

[0081] S210: If a component-level fault or a system-level fault is found, the test is terminated;

[0082] S220: If there is no component-level or system-level fault, use the refrigeration system twin model to calculate and output the simulated characteristic parameters;

[0083] S300: Determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold;

[0084] S310: If the first threshold is not reached, the test ends and it is confirmed that there is no refrigerant leakage in the system;

[0085] S320: If the first threshold is reached, the attenuation factor of the terminal component is decoupled according to the operating parameters of the refrigeration system, and the attenuation factor of the terminal component is substituted into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters.

[0086] S400: Determine whether the difference between the corrected simulated characteristic parameters and the actual characteristic parameters reaches the second threshold;

[0087] S410: If the second threshold is not reached, it is determined that there is no refrigerant leak in the system;

[0088] S420: If the second threshold is reached, a refrigerant leak in the system is determined.

[0089] In this embodiment, after initially obtaining the relevant parameters, a preliminary judgment is made on whether there is a component-level fault or system fault in the vehicle's refrigeration system. If such a fault exists, the test is stopped directly, and the component-level fault or system fault in the vehicle's refrigeration system is resolved first. If the component-level fault or system fault in the refrigeration system is ruled out, subsequent tests are performed as described in the above embodiment to determine whether there is a refrigerant leak in the refrigeration system.

[0090] Furthermore, such as Figure 5 As shown, the detection method includes the following steps:

[0091] S100: Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands;

[0092] S200: Determine if there is a component-level or system-level fault in the refrigeration system;

[0093] S210: If a component-level fault or a system-level fault is found, the test is terminated;

[0094] S220: If there is no component-level or system-level fault, use the refrigeration system twin model to calculate and output the simulated characteristic parameters;

[0095] S300: Determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold;

[0096] S310: If the first threshold is not reached, the test ends and it is confirmed that there is no refrigerant leakage in the system;

[0097] S320: If the first threshold is reached, the attenuation factor of the terminal component is decoupled according to the operating parameters of the refrigeration system, and the attenuation factor of the terminal component is substituted into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters.

[0098] S340: Compare whether the attenuation factor of the terminal component is greater than 20%;

[0099] S341: If it is greater than 20%, the output terminal component has an attenuation fault;

[0100] S342: If it is not greater than 20%, then there is no output attenuation fault in the terminal component;

[0101] S330: Substitutes the attenuation factor of the terminal component into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters;

[0102] S400: Determine whether the difference between the corrected simulated characteristic parameters and the actual characteristic parameters reaches the second threshold;

[0103] S410: If the second threshold is not reached, it is determined that there is no refrigerant leak in the system;

[0104] S420: If the second threshold is reached, a refrigerant leak in the system is determined.

[0105] In this embodiment, after decoupling and obtaining the attenuation factors of each component of the refrigeration system, the attenuation factors of each component are judged and compared to determine whether the attenuation factor is greater than 20%. If it is greater than 20%, an attenuation fault of the terminal component of the refrigeration system will be output, which means that the performance of the terminal component of the refrigeration system is poor and needs to be maintained or replaced. However, this does not mean that the refrigerant is leaking, which allows the user to perform more targeted maintenance on the refrigeration system. If the attenuation factor is not greater than 20%, there is no attenuation fault of the terminal component, which means that the performance of the terminal component of the refrigeration system can still meet the usage requirements. It should be noted that the value of the attenuation factor can be selected according to different detection scenarios.

[0106] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for detecting refrigerant leaks in vehicles, characterized in that, The detection method includes the following steps: Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands; use the refrigeration system twin model to calculate and output simulated characteristic parameters; and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold. If the first threshold is not reached, the test ends to confirm that there is no refrigerant leakage in the system; if the first threshold is reached, the attenuation factor of the terminal component is decoupled according to the operating parameters of the refrigeration system, the attenuation factor of the terminal component is substituted into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters, and it is determined whether the difference between the corrected simulation characteristic parameters and the actual characteristic parameters reaches the second threshold. If the second threshold is not reached, it is determined that there is no refrigerant leak in the system; if the second threshold is reached, it is determined that there is a refrigerant leak in the system.

2. The method for detecting refrigerant leakage in vehicles according to claim 1, characterized in that, The step "Decouple the attenuation factor of the terminal component based on the operating parameters of the refrigeration system" is as follows: Based on the refrigeration system operating parameters, decouple at least one of the following: compressor efficiency attenuation factor, valve flow attenuation factor, high-pressure heat transfer attenuation factor, and low-pressure heat transfer attenuation factor.

3. The method for detecting refrigerant leakage in vehicles according to claim 2, characterized in that, Based on the feedback values ​​of the high and low pressure temperature and pressure sensors at the compressor's intake and exhaust ports, and the compressor's feedback power, the compressor's isentropic efficiency is calculated and compared with the initial isentropic efficiency in the twin model to obtain the compressor efficiency decay factor.

4. The method for detecting refrigerant leakage in vehicles according to claim 2, characterized in that, The valve flow rate attenuation factor is calculated based on the refrigerant flow rate output from the twin model of the refrigeration system.

5. The method for detecting refrigerant leakage in vehicles according to claim 2, characterized in that, The high-pressure heat transfer attenuation factor is calculated based on the system high pressure, ambient temperature, refrigerant flow rate, and PWM feedback value of the condenser fan.

6. The method for detecting refrigerant leakage in vehicles according to claim 2, characterized in that, The low-pressure heat transfer attenuation factor is calculated based on the system low pressure, HVAC inlet air temperature and humidity, and blower air volume.

7. The method for detecting refrigerant leakage in vehicles according to any one of claims 1 to 6, characterized in that, The environmental parameters include at least one of sunlight, ambient temperature and humidity, and cabin temperature and humidity; and / or The refrigeration system setting parameters include at least one of the following: set temperature, air volume setting, internal / external circulation setting, and cooling / heating setting; and / or The vehicle operating parameters include vehicle speed; and / or The system terminal component control commands include at least one of the following: compressor speed command, valve opening degree command, valve opening degree command, fan PWM command, fresh air damper opening degree command, and mixing air damper opening degree command.

8. The method for detecting refrigerant leakage in vehicles according to claim 1, characterized in that, The step "Use a twin model of the refrigeration system to calculate and output simulated characteristic parameters, and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold" specifically involves: The outlet air temperature of the simulated evaporator cooling mode is calculated and output using a twin model of the refrigeration system. The difference between the simulated outlet air temperature and the actual outlet air temperature is compared to see if it is greater than 5°C and lasts for 5 minutes.

9. The method for detecting refrigerant leakage in vehicles according to claim 1, characterized in that, Following the step "decoupling the attenuation factor of the terminal component based on the operating parameters of the refrigeration system", the detection method further includes: Compare whether the attenuation factor of the terminal component is greater than a set percentage. If it is greater than the set percentage, it is determined that there is an attenuation fault in the terminal component; if it is not greater than the set percentage, it is determined that there is no attenuation fault in the terminal component.

10. The method for detecting refrigerant leakage in vehicles according to claim 1, characterized in that, The step "obtain at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands; calculate and output simulated characteristic parameters using a refrigeration system twin model; and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches a first threshold" further includes: Acquire at least one of the following: environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control commands, and determine whether there is a refrigeration system component-level fault or a system-level fault. If a component-level or system-level fault exists, the test ends; if no component-level or system-level fault exists, the refrigeration system twin model is used to calculate and output simulated characteristic parameters to determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold.

Images