CN116373541A - Leak detection method of vehicle refrigerant - Google Patents

Abstract

The invention relates to the technical field of refrigeration systems, in particular to a method for detecting leakage of a vehicle refrigerant, and aims to solve the problem that in the prior art, the detection result of the leakage of the refrigerant in the vehicle refrigeration system is inaccurate. Therefore, the detection method of the invention eliminates the fault of the refrigeration system component level or the system fault by acquiring the related parameters, uses the digital twin model to output the simulation operation characteristic parameters, further decouples the attenuation factors of the key components when the output result and the existing operation characteristics of the system are different, calibrates the digital twin model, uses the calibrated model to carry out characteristic parameter operation again, judges the refrigerant leakage if the difference still exists, utilizes the flexible modeling characteristics of the digital twin, is compatible with all configured and designed refrigerant systems, can match the vehicle state and the operation environment in real time, simultaneously introduces the component attenuation factors to avoid the influence of the component level performance attenuation on the diagnosis result, and has more accurate detection result.

Description

Leak detection method of vehicle refrigerant

technical field

The invention relates to the technical field of refrigeration systems, and specifically provides a vehicle refrigerant leakage detection method.

Background technique

With the development of society, the number of vehicles is still growing. People are more and more chasing the comfort of vehicles in addition to the performance of vehicles. The refrigeration system for vehicles is an important part of the vehicle, and the quality of the refrigeration system affects the comfort of the vehicle to a certain extent. Therefore, it is necessary to carry out effective testing for the vehicle refrigeration system to improve the user experience.

Leakage of refrigerant used in vehicles is one of the most common causes of refrigeration system failure or performance degradation. In the prior art, most of the components rely on the comparison between the operating status of the components and the established preset values, and it is difficult to consider the impact of environmental changes or component attenuation changes. The impact of detection results, such as a patented refrigerant leakage protection method with application number 2017103964430, uses the electrical parameters of the compressor to detect refrigerant leakage, but the performance of the car compressor decays quickly, and it is difficult to separate the unhealthy state of the compressor from the detection The impact of the results; another example is the patent application number 2016103082337, a refrigerant leakage detection method and air-conditioning device, using the coil temperature, indoor temperature and low-pressure parameters to judge, only the system performance can be judged to be attenuated, and the sunlight and fresh air load are severe Misjudgments may occur when changing vehicle scenarios, or other system or component failures cause poor cooling performance in the cabin.

Correspondingly, there is a need in the art for a new vehicle refrigerant leakage detection method to solve the above problems.

Contents of the invention

The present invention aims to solve the above-mentioned technical problems, that is, to solve the problem of inaccurate detection results in the refrigerant leakage detection in the refrigeration system for vehicles in the prior art. For this purpose, the present invention provides a kind of vehicle refrigerant leakage detection method, and this detection method comprises the following steps:

Obtain at least one of the environmental parameters, refrigeration system setting parameters, vehicle operating parameters and system terminal component control instructions, use the twin model of the refrigeration system to calculate and output the simulation characteristic parameters, and determine whether the difference between the simulation characteristic parameters and the actual characteristic parameters reaches the second a threshold;

If it does not reach the first threshold, end the test and determine that there is no refrigerant leakage in the system; if it reaches the first threshold, decouple the attenuation factor of the terminal components according to the refrigeration system operating parameters, and substitute the attenuation factor of the terminal components into the refrigeration system twin model calculation And output the corrected analog characteristic parameter, and determine whether the difference between the corrected simulated characteristic parameter and the actual characteristic parameter reaches the second threshold;

If the second threshold is not reached, it is determined that there is no refrigerant leakage in the system; if the second threshold is reached, it is determined that the system refrigerant is leaking.

In the above-mentioned specific implementation of the method for detecting refrigerant leakage in a vehicle, the step "decoupling the attenuation factor of the terminal components according to the operating parameters of the refrigeration system" is specifically:

At least one of the compressor efficiency attenuation factor, the valve flow attenuation factor, the high-pressure heat transfer attenuation factor, and the low-pressure heat transfer attenuation factor is decoupled according to the refrigeration system operating parameters.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, the isentropic efficiency of the compressor is calculated and compared with The initial isentropic efficiency in the twin model is compared and the compressor efficiency decay factor is obtained.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, the valve flow attenuation factor is calculated according to the refrigerant flow output by the twin model of the refrigeration system.

In the above specific implementation of the refrigerant leakage detection method, the high-pressure side heat transfer attenuation factor is calculated according to the system high pressure, ambient temperature, refrigerant flow rate, and the PWM feedback value of the condensing fan.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, the heat transfer attenuation factor at the low pressure side is calculated according to the low pressure of the system, the temperature and humidity of the HVAC inlet air, and the air volume of the blower.

In the above-mentioned specific implementation of the method for detecting refrigerant leakage in a vehicle, 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 set temperature, air volume setting, internal and external cycle setting, and cooling and heating setting; and/or

The vehicle operating parameters include vehicle speed; and/or

The system terminal component control command includes at least one of compressor speed command, valve opening and closing degree command, valve opening degree command, fan PWM command, fresh air damper opening degree and mixed air damper opening degree command.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, the step "use the twin model of the refrigeration system to calculate and output the simulated characteristic parameters, and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold" is specifically:

Use the twin model of the refrigeration system to calculate and output the simulated evaporator cooling mode outlet air temperature, and compare whether the difference between the simulated evaporator cooling mode outlet air temperature and the actual outlet air temperature is greater than 5°C and lasts for 5 minutes.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, after the step "decoupling the attenuation factor of the terminal component according to the refrigeration system operating parameters", the detection method further includes:

Comparing whether the attenuation factor of the terminal component is greater than the set percentage, if it is greater than the set percentage, it is determined that there is an attenuation fault of the terminal component; if it is not greater than the set percentage, it is determined that there is no attenuation fault of the terminal component.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, the step "acquire at least one of the environmental parameters, refrigeration system setting parameters, vehicle operating parameters and system terminal component control instructions, use the twin model of the refrigeration system to calculate and output Simulate the characteristic parameter, determine whether the difference between the simulated characteristic parameter and the actual characteristic parameter reaches the first threshold value” is further:

Obtain at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control instructions, and determine whether there is a refrigeration system component-level fault or a system-level fault;

If there is a component-level fault or system-level fault, end the test; if there is no component-level fault or system-level fault, use the twin model of the refrigeration system to calculate and output the simulated characteristic parameters, and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters is reached the first threshold.

In the above-mentioned specific implementation of the vehicle refrigerant leakage detection method, the component-level failure includes at least one of compressor shutdown, valve shutdown, fan degradation or shutdown, and refrigerant temperature and pressure sensor failure; and/or

The system level faults include blockages.

Scheme 1. A method for detecting leakage of vehicle refrigerant, characterized in that the detection method comprises the following steps:

Obtain at least one of the environmental parameters, refrigeration system setting parameters, vehicle operating parameters and system terminal component control instructions, use the twin model of the refrigeration system to calculate and output the simulation characteristic parameters, and determine whether the difference between the simulation characteristic parameters and the actual characteristic parameters reaches the second a threshold;

If it does not reach the first threshold, end the test and determine that there is no refrigerant leakage in the system; if it reaches the first threshold, decouple the attenuation factor of the terminal components according to the refrigeration system operating parameters, and substitute the attenuation factor of the terminal components into the refrigeration system twin model calculation And output the corrected analog characteristic parameter, and determine whether the difference between the corrected simulated characteristic parameter and the actual characteristic parameter reaches the second threshold;

If the second threshold is not reached, it is determined that there is no refrigerant leakage in the system; if the second threshold is reached, it is determined that the system refrigerant is leaking.

Scheme 2. The vehicle refrigerant leakage detection method according to Scheme 1, characterized in that the step "decoupling the attenuation factor of the terminal components according to the refrigeration system operating parameters" is specifically:

At least one of the compressor efficiency attenuation factor, the valve flow attenuation factor, the high-pressure heat transfer attenuation factor, and the low-pressure heat transfer attenuation factor is decoupled according to the refrigeration system operating parameters.

Scheme 3. According to the vehicle refrigerant leakage detection method described in Scheme 2, it is characterized in that, according to the high and low pressure temperature and pressure sensor feedback values and compressor feedback power of the air inlet and exhaust port of the compressor, the compressor is calculated. The isentropic efficiency is compared with the initial isentropic efficiency in the twin model to obtain the compressor efficiency decay factor.

Scheme 4. The vehicle refrigerant leakage detection method according to scheme 2, characterized in that the valve flow attenuation factor is calculated according to the refrigerant flow rate output by the twin model of the refrigeration system.

Scheme 5. The vehicle refrigerant leakage detection method according to scheme 2, characterized in that the heat transfer attenuation factor on the high pressure side is calculated according to the system high pressure, ambient temperature, refrigerant flow rate and the PWM feedback value of the condensing fan.

Scheme 6. The vehicle refrigerant leakage detection method according to scheme 2, characterized in that the heat transfer attenuation factor on the low pressure side is calculated according to the low pressure of the system, the temperature and humidity of the HVAC inlet air, and the air volume of the blower.

Scheme 7. The vehicle refrigerant leakage detection method according to any one of schemes 1 to 6, wherein 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 set temperature, air volume setting, internal and external cycle setting, and cooling and heating setting; and/or

The vehicle operating parameters include vehicle speed; and/or

The system terminal component control command includes at least one of compressor speed command, valve opening and closing degree command, valve opening degree command, fan PWM command, fresh air damper opening degree and mixed air damper opening degree command.

Scheme 8. The vehicle refrigerant leakage detection method according to any one of schemes 1 to 7, characterized in that the step "uses the twin model of the refrigeration system to calculate and output the simulated characteristic parameters, and determines the difference between the simulated characteristic parameters and the actual characteristic parameters. Whether the difference reaches the first threshold" is specifically:

Use the twin model of the refrigeration system to calculate and output the simulated evaporator cooling mode outlet air temperature, and compare whether the difference between the simulated evaporator cooling mode outlet air temperature and the actual outlet air temperature is greater than 5°C and lasts for 5 minutes.

Scheme 9. The vehicle refrigerant leakage detection method according to any one of schemes 1 to 8, characterized in that, after the step "decoupling the attenuation factor of the terminal components according to the refrigeration system operating parameters", the detection method further includes :

Comparing whether the attenuation factor of the terminal component is greater than the set percentage, if it is greater than the set percentage, it is determined that there is an attenuation fault of the terminal component; if it is not greater than the set percentage, it is determined that there is no attenuation fault of the terminal component.

Scheme 10. The vehicle refrigerant leakage detection method according to any one of schemes 1 to 9, characterized in that the step "obtain at least one of the environmental parameters, refrigeration system setting parameters, vehicle operating parameters and system terminal component control instructions One, use the twin model of the refrigeration system to calculate and output the simulated characteristic parameters, and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters reaches the first threshold" is further:

Obtain at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control instructions, and determine whether there is a refrigeration system component-level fault or a system-level fault;

If there is a component-level fault or system-level fault, end the test; if there is no component-level fault or system-level fault, use the twin model of the refrigeration system to calculate and output the simulated characteristic parameters, and determine whether the difference between the simulated characteristic parameters and the actual characteristic parameters is reached the first threshold.

Solution 11. The vehicle refrigerant leakage detection method according to solution 10, wherein the component-level failure includes at least one of compressor shutdown, valve shutdown, fan downgrade or shutdown, and refrigerant temperature and pressure sensor failure ; and/or

The system level faults include blockages.

In the case of adopting the above technical solution, the present invention can obtain vehicle parameters, eliminate component-level faults or system-level faults of the vehicle itself, use the digital twin as a diagnostic tool, and output in real time through the digital twin model of the refrigerant system that has been checked Operating characteristic parameters, when there are differences between the output results and the existing operating characteristics of the system, further decouple the attenuation factors of key components, calibrate the digital twin model, and use the calibrated model to perform characteristic parameter calculations again. If there are still differences, then It is judged as refrigerant leakage, so as to improve the detection accuracy of refrigerant in the vehicle refrigeration system; this method uses the flexible modeling characteristics of digital twins, is compatible with all configured and designed refrigerant systems, and can match the vehicle status and operating environment in real time. The component attenuation factor avoids the impact of component-level performance attenuation on the diagnosis results. After calculation, component attenuation faults and refrigerant leakage faults can be output synchronously.

Description of drawings

Describe preferred embodiment of the present invention below in conjunction with accompanying drawing, in the accompanying drawing:

Fig. 1 is a schematic diagram of the main steps of the detection method in the present invention;

Fig. 2 is a layout diagram of a vehicle air-conditioning system according to one embodiment of the present invention;

Fig. 3 is a threshold judgment basis diagram of one embodiment of the present invention;

Fig. 4 is a schematic diagram of the steps of one embodiment of the detection method in the present invention, which shows the steps of judging vehicle component level or system level faults;

Fig. 5 is a schematic diagram of the steps of one embodiment of the detection method in the present invention, which shows the steps of judging the attenuation performance of the vehicle components.

In the figure: 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 ways

The preferred embodiment of the present invention will be described below with reference to the accompanying drawings and in combination with the vehicle air-conditioning and refrigeration system. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention, and are not used to limit the protection scope of the present invention. Those skilled in the art can make adjustments as needed so as to adapt to specific applications. For example, although the description is described in conjunction with the vehicle air-conditioning and refrigeration system, this is not limiting, and those skilled in the art can apply the present invention to any other refrigeration system as required, as long as the refrigeration system has the ability to detect refrigerant Leakage is required, but the functional attenuation of the components will affect the accuracy of the test results.

In addition, it should be noted that, in the description of the present invention, unless otherwise specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection Or integrated connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Moreover, in order to show the core technical solution of the present invention more clearly, the description of the known structures of the air-conditioning system for vehicles is omitted in the following description, but this omission is only for convenience of description, and does not mean that the air-conditioning system for vehicles These structures may not exist.

As shown in Figure 1, the present invention proposes a kind of vehicle refrigerant leakage detection method, and this detection method comprises the following steps:

S100: Obtain at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control instructions, and use the refrigeration system twin model to calculate and output simulation characteristic parameters;

S200: Determine whether the difference between the simulated characteristic parameter and the actual characteristic parameter reaches a first threshold;

S210: If the first threshold is not reached, end the test, and determine that there is no refrigerant leakage in the system;

S220: If the first threshold is reached, decoupling the attenuation factor of the terminal component according to the refrigeration system operating parameters, substituting the attenuation factor of the terminal component into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters;

S300: Determine whether the difference between the corrected simulated characteristic parameter and the actual characteristic parameter reaches a second threshold;

S310: If the second threshold is not reached, determine that the system has no refrigerant leakage;

S320: If the second threshold is reached, determine that the system refrigerant leaks.

In this embodiment, by using the digital twin model of the refrigeration system, the parameters are obtained and then substituted into the digital twin model of the refrigeration system to obtain the simulated characteristic parameters, and a preliminary judgment is made on whether there is refrigerant leakage in the refrigeration system, and then in order to make the detection results more accurate, avoid refrigeration The performance attenuation of the components of the system affects the detection results. The attenuation factors of the refrigeration system components are decoupled, the digital twin model of the refrigeration system is corrected, and the parameters are substituted into the model to calculate again and output the simulation characteristic parameters, which are compared with the actual characteristic parameters. comparison, to obtain the final accurate conclusion.

It should be noted that, in the above-mentioned embodiments, the digital twin model of the refrigeration system is based on physical principles, mathematics and computer modeling, etc., and digitally constructs a real refrigeration system model. By combining the operating environment and The control instructions are substituted into the twin model in digital form. The twin model can simulate the operation of the refrigeration system to obtain simulated characteristic parameters, so as to facilitate comparison with the actual operating parameters of the refrigeration system. In addition, the digital twin model of the refrigeration system can be based on the performance of the terminal components The parameter decay is adjusted accordingly to be consistent with the vehicle cooling system.

The digital information required by the above-mentioned twin model can be obtained by means of sensors, monitoring equipment, computer software, etc., and the parameters required for the relevant detection initially obtained may change in some detection scenarios, which does not affect the scope of the present invention. The scope of protection, that is to say, without deviating from the technical concept of the present invention, embodiments that obtain other relevant parameters and adopt a digital twin model to eliminate the attenuation effect and thereby improve the accuracy of detection results should also fall within the scope of protection of the present invention.

Based on the above-mentioned embodiment, referring to Fig. 2, the vehicle air-conditioning system operates in cooling mode, and the arrow indicates the direction of refrigerant flow. The embodiment of the present invention will be described in conjunction with the vehicle air-conditioning system, and environmental parameters will be collected, including but not limited to sunshine conditions, Ambient temperature and humidity, temperature and humidity inside the car; air conditioner setting parameters, including but not limited to air conditioner set temperature, air volume, internal and external circulation settings, cooling mode or heating mode setting; vehicle operating parameter collection such as vehicle speed Conditions; the control commands of the terminal components of the refrigeration system include but are not limited to the compressor speed command, valve opening and closing degree, valve opening degree command, fan PWM command, fresh air damper opening degree, mixed air damper opening degree command, etc. The above parameters can be collected according to The parameters required for the calculation of the digital twin model of the refrigeration system are adjusted adaptively. After the parameters are substituted into the twin model, the simulation characteristic parameters of the refrigeration system are simulated and output. To judge whether there is refrigerant leakage in the refrigeration system, the simulated characteristic parameters are used to simulate the outlet air temperature of the evaporator. It should be noted that when testing other refrigeration systems, the characteristic parameters can have other options. The above simulated values and the actual vehicle Values are compared to preliminarily determine whether there is refrigerant leakage.

The first threshold and the second threshold are used to compare the air outlet temperature of the simulated evaporator with the actual air outlet temperature of the evaporator. The first threshold can be set to be the same or different according to the test requirements. In this embodiment, it is set to simulate evaporation. Whether the temperature difference between the air outlet temperature of the evaporator and the actual air outlet temperature of the evaporator is greater than 5°C and lasts for 5 minutes, it needs to be explained that the first threshold and the second threshold determine the specific situation, and corresponding adjustments need to be made according to the specific conditions of the detected target.

In this embodiment, the basis for adopting the above threshold value is as follows. Referring to Figure 2 and Figure 3, the operating system adopts the air conditioning system shown in Figure 2, operates in cooling mode, and confirms that the performance of each component has no attenuation. The relevant test parameter is the test ambient temperature : Ambient temperature 30°C, RH52%, no sunshine; vehicle speed: idling speed; air conditioning setting: temperature 23°C, automatic air volume, automatic internal and external circulation.

The initial charging amount is 300g, and then refill according to 100g each time until the minimum nominal charging amount is 700g; when the charging amount is 300g, the temperature difference between the actual air outlet and the theoretical air outlet is about 25°C, and the actual air outlet corresponding to 400g The temperature difference from the theoretical air outlet is 20°C, the temperature difference between 500g and 600g is about 10°C, and when the nominal charge is reached, the temperature difference test result is -2°C. Considering that the refrigerant leakage is expected to be detected within 100g, the temperature difference is set at 5°C to judge the refrigerant leakage, and at the same time, when the compressor starts to run (about 100s), the system is in a transient state and the operation is unstable. At this time, the error of the calculation result of the twin model It will be slightly larger, so set the temperature difference duration to 5 minutes to avoid misjudgment.

Based on the above basis, when the first simulated evaporator outlet temperature and the actual evaporator outlet temperature are within the first threshold, it can be judged that there is no refrigerant leakage; when it exceeds the first threshold range, the attenuation factor needs to be decoupled, 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 twin model of the refrigeration system contains other The twin model of the component, for example, the valve flow attenuation factor can be calculated through the twin model of the compressor and the twin model of the valve, in which the high pressure and low pressure of the system are respectively obtained by the high pressure temperature and pressure sensor and the low pressure temperature and pressure sensor and participate in the calculation of the corresponding attenuation factor; After the attenuation factor of each component, the digital twin model of the refrigeration system is corrected, and then substituted into the model to obtain the second simulated evaporator outlet air temperature. If it does not exceed the second threshold at this time, it means that the evaporator air outlet is caused by component performance attenuation. If the temperature is difficult to reach the standard, it is not a refrigerant leakage; and if it still exceeds the second threshold at this time, it can be determined that there is a refrigerant leakage in the refrigeration system.

Further, as shown in Figure 4, the detection method includes the following steps:

S100: Obtain at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control instructions;

S200: Determine whether there is a refrigeration system component-level fault or a system-level fault;

S210: If there is a component-level fault or a system-level fault, end the test;

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

S300: Determine whether the difference between the simulated characteristic parameter and the actual characteristic parameter reaches a first threshold;

S310: If the first threshold is not reached, end the test, and determine that there is no refrigerant leakage in the system;

S320: If the first threshold is reached, decoupling the attenuation factor of the terminal component according to the refrigeration system operating parameters, substituting the attenuation factor of the terminal component into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters;

S400: Determine whether the difference between the corrected simulated characteristic parameter and the actual characteristic parameter reaches a second threshold;

S410: If the second threshold is not reached, determine that the system has no refrigerant leakage;

S420: If the second threshold is reached, determine that the system refrigerant leaks.

In this embodiment, after the initial acquisition of relevant parameters, a preliminary judgment will be made on whether there is a failure at the refrigeration system component level or a system failure in the refrigeration system of the vehicle. Faults or system faults, if component-level faults or system faults of the refrigeration system are ruled out, follow-up tests are performed as described in the above embodiments to determine whether there is refrigerant leakage in the refrigeration system.

Further, as shown in Figure 5, the detection method includes the following steps:

S100: Obtain at least one of environmental parameters, refrigeration system setting parameters, vehicle operating parameters, and system terminal component control instructions;

S200: Determine whether there is a refrigeration system component-level fault or a system-level fault;

S210: If there is a component-level fault or a system-level fault, end the test;

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

S300: Determine whether the difference between the simulated characteristic parameter and the actual characteristic parameter reaches a first threshold;

S310: If the first threshold is not reached, end the test, and determine that there is no refrigerant leakage in the system;

S320: If the first threshold is reached, decoupling the attenuation factor of the terminal component according to the refrigeration system operating parameters, substituting the attenuation factor of the terminal component into the twin model of the refrigeration system to calculate and output the corrected simulation characteristic parameters;

S340: comparing whether the attenuation factor of the terminal part is greater than 20%;

S341: If it is greater than 20%, the attenuation failure of the output terminal part;

S342: If it is not greater than 20%, the output has no terminal component attenuation failure;

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

S400: Determine whether the difference between the corrected simulated characteristic parameter and the actual characteristic parameter reaches a second threshold;

S410: If the second threshold is not reached, determine that the system has no refrigerant leakage;

S420: If the second threshold is reached, determine that the system refrigerant leaks.

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%, and if it is greater than 20%, the attenuation of the terminal components of the refrigeration system will be output Failure means that the performance of the terminal parts of the refrigeration system is poor and needs to be maintained or replaced, but this is not a refrigerant leakage, which enables users to maintain the refrigeration system more targetedly; if the attenuation factor is not greater than 20%, then There is no attenuation failure of terminal components, that is, the performance of the terminal components of the refrigeration system can still meet the requirements of use. It should be noted that the value of the attenuation factor can be selected under different detection scenarios.

So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings, but those skilled in the art will easily understand that the protection scope 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 relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims (10)

1. A refrigerant leakage detection method for a vehicle, characterized by comprising the steps of:

acquiring at least one of environmental parameters, refrigerating system setting parameters, vehicle running parameters and system terminal component control instructions, calculating and outputting simulation characteristic parameters by using a refrigerating system twin model, and determining whether the difference value between the simulation characteristic parameters and actual characteristic parameters reaches a first threshold value;

if the first threshold is not reached, ending the test, and determining that the system has no refrigerant leakage; if the first threshold is reached, decoupling the attenuation factor of the terminal part according to the operation parameter of the refrigeration system, substituting the attenuation factor of the terminal part into the twin model of the refrigeration system to calculate and output a correction simulation characteristic parameter, and determining whether the difference value between the correction simulation characteristic parameter and the actual characteristic parameter reaches a second threshold;

if the second threshold is not reached, determining that the system is free of refrigerant leakage; if the second threshold is reached, a system refrigerant leak is determined.

2. The refrigerant leakage detection method for a vehicle according to claim 1, wherein the step of decoupling the attenuation factor of the terminal member according to the operation parameter of the refrigeration system is specifically:

at least one of the compressor efficiency decay factor, the valve flow decay factor, the high pressure heat transfer decay factor, the low pressure heat transfer decay factor is decoupled based on the refrigeration system operating parameters.

3. The refrigerant leakage detecting method for vehicles according to claim 2, wherein the isentropic efficiency of the compressor is calculated based on the feedback values of the high and low pressure temperature and pressure sensors of the suction port and the discharge port of the compressor and the feedback power of the compressor, and is compared with the initial isentropic efficiency in the twin model to obtain the efficiency attenuation factor of the compressor.

4. The refrigerant leak detection method for a vehicle as recited in claim 2, wherein the valve flow rate attenuation factor is calculated from a refrigerant flow rate output from a refrigerant system twinning model.

5. The refrigerant leakage detection method for a vehicle according to claim 2, wherein the high-pressure side heat transfer attenuation factor is calculated based on a system high pressure, an ambient temperature, a refrigerant flow rate, and a PWM feedback value of a condensing fan.

6. The method of claim 2, wherein the low pressure side heat transfer attenuation factor is calculated based on system low pressure, HVAC inlet air temperature and humidity, and blower air volume.

7. The refrigerant leak detection method for a vehicle according to any one of claims 1 to 6, characterized in that the environmental parameter includes at least one of sunlight, ambient temperature and humidity, cabin temperature and humidity; and/or

The refrigerating system setting parameters comprise at least one of a set temperature, an air quantity setting, an internal and external circulation setting and a refrigerating and heating setting; and/or

The vehicle operating parameters include vehicle speed; and/or

The system terminal component control instruction comprises at least one of a compressor rotating speed instruction, a valve opening and closing degree instruction, a valve opening instruction, a fan PWM instruction, a fresh air door opening and a mixed air door opening instruction.

8. The refrigerant leakage detection method for a vehicle according to any one of claims 1 to 7, wherein the step of calculating and outputting the simulated characteristic parameter using the refrigeration system twin model, and determining whether the difference between the simulated characteristic parameter and the actual characteristic parameter reaches the first threshold value is specifically:

and calculating and outputting the air-out temperature of the simulated evaporator refrigeration mode by using the refrigeration system twin model, and comparing whether the difference between the air-out temperature of the simulated evaporator refrigeration mode and the actual air-out temperature is greater than 5 ℃ for 5min.

9. The refrigerant leakage detection method for a vehicle according to any one of claims 1 to 8, wherein after the step of decoupling the attenuation factor of the terminal member according to the refrigeration system operation parameter, the detection method further comprises:

comparing whether the attenuation factor of the terminal component is larger than a set percentage, and if so, determining that the attenuation fault of the terminal component exists; if not greater than the set percentage, no termination component attenuation fault is determined.

10. The refrigerant leakage detection method for a vehicle according to any one of claims 1 to 9, wherein the step of "obtaining at least one of an environmental parameter, a refrigeration system setting parameter, a vehicle running parameter, and a system terminal part control instruction, calculating and outputting a simulated characteristic parameter using a refrigeration system twin model, determining whether a difference between the simulated characteristic parameter and an actual characteristic parameter reaches a first threshold value" is further:

acquiring at least one of environment parameters, refrigerating system setting parameters, vehicle running parameters and system terminal component control instructions, and judging whether refrigerating system component level faults or system level faults exist or not;

ending the test if there is a component level failure or a system level failure; if there is no component level fault or system level fault, calculating and outputting simulation characteristic parameters by using a twin model of the refrigeration system, and determining whether the difference value between the simulation characteristic parameters and the actual characteristic parameters reaches a first threshold value.

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