Test method for refrigerant charge quantity of double independent air conditioning system and filling system

Abstract

The invention discloses a testing method and a filling system for the refrigerant charge quantity of a double-independent air-conditioning system, and belongs to the technical field of vehicle tests.The testing method includes the steps that a rear air conditioner is filled with a refrigerant according to a theoretical charge quantity value, the refrigerant is charged into a front air conditioner from the initial charge quantity, and the front air conditioner is filled with the refrigerant from the initial charge quantity; the filling amount is gradually increased until the first preset filling amount is reached; in this way, according to the filling range from the initial filling amount to the first preset filling amount of the refrigerant, the optimal filling amount of the refrigerant of the air conditioner can be obtained through calculation; according to the filling range from the initial filling amount to the second preset filling amount of the refrigerant, the optimal filling amount of the refrigerant of the rear air conditioner is calculated, and therefore the optimal filling amount of the refrigerant of the front air conditioner and the optimal filling amount of the refrigerant of the rear air conditioner can be accurately calculated. And an important reference can be provided for the charge quantity confirmation test of the double-independent air-conditioning system.

Description

Technical Field

[0001] This invention relates to the field of vehicle testing technology, and in particular to a test method and charging system for the refrigerant charge of a dual independent air conditioning system. Background Technology

[0002] With the continuous advancement of new energy vehicle technology and the reduction in costs, the competitiveness of hybrid buses is constantly increasing. Compared with traditional fuel buses, hybrid buses have significant advantages in energy conservation, emission reduction, and operating costs, and are therefore widely used in urban public transportation.

[0003] However, in the automotive air conditioning sector, the existing market lacks large-displacement electric compressors, making it difficult to meet the summer cooling needs of buses. Furthermore, the large size of the vehicles makes refrigerant flow distribution difficult. To address these issues, some buses employ dual independent air conditioning systems. Traditional fuel-powered buses and new energy vehicles each have only one air conditioning system. Therefore, the market only offers refrigerant charge verification test methods for single air conditioning systems. If traditional refrigerant charge verification test methods are used, it is impossible to accurately verify the refrigerant charge of dual air conditioning systems, and there is a risk of battery overheating and test failure. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a test method for the refrigerant charge of a dual independent air conditioning system, which can effectively improve the accuracy of test results and provide an important reference for the charge verification test of dual independent air conditioning systems.

[0005] The present invention also provides a charging system and control device for applying the above-described test method for refrigerant charge amount in a dual independent air conditioning system.

[0006] According to the test method for refrigerant charge of a dual independent air conditioning system of the first aspect of the present invention, applied to a hybrid bus having a dual independent air conditioning system, the dual independent air conditioning system including a front air conditioner and a rear air conditioner, the test method includes: Sensors were installed on the test vehicle and calibrated. The test vehicle was placed in an environmental chamber, and the temperature inside the environmental chamber was adjusted to reach the set temperature. Refrigerant is charged into the rear air conditioner according to the theoretical charge amount, and the refrigerant pipeline of the front air conditioner is evacuated. Start the test vehicle and turn on the front air conditioner and the rear air conditioner. Start charging the front air conditioner with refrigerant from the initial charge amount and gradually increase the charge amount until the first preset charge amount is reached. The optimal refrigerant charge for the front air conditioner is calculated based on the refrigerant charge range from the initial charge amount to the first preset charge amount. The refrigerant lines of the rear air conditioner were evacuated, and the test vehicle was restarted, with both the front and rear air conditioners turned on. The refrigerant is charged into the rear air conditioner starting from the initial charge amount, and the charge amount is gradually increased until the second preset charge amount is reached; The optimal refrigerant charge for the rear air conditioner is calculated based on the refrigerant charge range from the initial charge amount to the second preset charge amount.

[0007] The test method for refrigerant charge of a dual independent air conditioning system according to an embodiment of the present invention has at least the following beneficial effects: The experimental method of this invention first involves installing sensors on a test vehicle and calibrating them; then, placing the test vehicle in an environmental chamber and adjusting the temperature within the chamber to a set temperature that simulates real-world ambient temperature; next, charging refrigerant into the rear air conditioner according to the theoretical charge amount, and evacuating the refrigerant piping of the front air conditioner; starting the test vehicle and turning on both the front and rear air conditioners, charging the front air conditioner with refrigerant starting from the initial charge amount and gradually increasing the charge amount until a first preset charge amount is reached; thus, based on the charge range from the initial charge amount to the first preset charge amount, the optimal refrigerant charge amount for the front air conditioner can be calculated; after determining the optimal charge amount for the front air conditioner... After determining the optimal refrigerant charge level for the air conditioner, the test vehicle is shut down, and the refrigerant lines of the rear air conditioner are evacuated. The test vehicle is then restarted, and both the front and rear air conditioners are turned on. Refrigerant is added to the rear air conditioner starting from the initial charge level, gradually increasing the charge until the second preset charge level is reached. The optimal refrigerant charge level for the rear air conditioner is then calculated based on the charge range from the initial charge level to the second preset charge level. This method accurately calculates the optimal refrigerant charge levels for both the front and rear air conditioners, offering high accuracy. It is suitable for hybrid buses with dual independent air conditioning systems and provides an important reference for confirming the refrigerant charge level for dual independent air conditioning systems, reducing the risk of refrigerant charging failure.

[0008] According to some embodiments of the present invention, the step of charging the refrigerant into the front air conditioner starting from an initial charge amount and gradually increasing the charge amount until a first preset charge amount is reached includes: The refrigerant is charged into the front air conditioner according to the initial charge amount, and then the refrigerant is added multiple times in succession with the charge amount increasing each time. The initial charge amount is the difference between the theoretical charge amount and the preset amount. When the refrigerant charge of the front air conditioner reaches the first preset charge amount, the control stops injecting refrigerant into the front air conditioner.

[0009] According to some embodiments of the present invention, controlling the stopping of refrigerant injection into the front air conditioner when the refrigerant charge of the front air conditioner reaches the first preset charge amount includes: Obtain the outlet pressure value of the indoor heat exchanger of the aforementioned air conditioner; When the outlet pressure of the indoor heat exchanger is greater than or equal to the first preset pressure value, the current refrigerant charge of the front air conditioner is determined to be the first preset charge, and the injection of refrigerant into the front air conditioner is stopped.

[0010] According to some embodiments of the present invention, the step of charging the refrigerant into the rear air conditioner starting from an initial charge amount and gradually increasing the charge amount until a second preset charge amount is reached includes: The refrigerant is charged into the rear air conditioner according to the initial charge amount, and then the refrigerant is added multiple times in succession with the charge amount increasing each time. The initial charge amount is the difference between the theoretical charge amount and the preset amount. When the refrigerant charge of the rear air conditioner reaches the second preset charge amount, the control stops injecting refrigerant into the rear air conditioner.

[0011] According to some embodiments of the present invention, controlling the stopping of refrigerant injection into the rear air conditioner when the refrigerant charge of the rear air conditioner reaches the second preset charge amount includes: Obtain the outlet pressure value of the indoor heat exchanger of the rear air conditioner; When the outlet pressure of the indoor heat exchanger is greater than or equal to the second preset pressure value, the current refrigerant charge of the rear air conditioner is determined to be the second preset charge, and the injection of refrigerant into the rear air conditioner is stopped.

[0012] According to some embodiments of the present invention, charging the rear air conditioner with refrigerant according to the theoretical charge amount includes: The theoretical value of the injection volume is calculated using the following formula: Q=(Vcomp +Vcond +Vevap +Vpipe) ρ; Where Q represents the theoretical charge of refrigerant (in kg), Vcomp represents the internal volume of the compressor (in m³), ​​Vcond represents the internal volume of the condenser (in m³), ​​Vevap represents the internal volume of the evaporator (in m³), ​​Vpipe represents the internal volume of the refrigerant piping (in m³), ​​and ρ represents the saturated liquid density of the refrigerant at 40℃ (in kg / m³).

[0013] According to some embodiments of the present invention, calculating the optimal refrigerant charge of the front air conditioner based on the refrigerant charge range from the initial charge amount to the first preset charge amount includes: Based on the refrigerant charging process from the initial charge amount to the first preset charge amount, a first lower limit and a first upper limit of the refrigerant charge amount are determined; The optimal refrigerant charge of the front air conditioner is calculated based on the first lower limit, the first upper limit, and the optimal charge calculation formula. The step of calculating the optimal refrigerant charge for the rear air conditioner based on the refrigerant charge range from the initial charge amount to the second preset charge amount includes: Based on the refrigerant charging process from the initial charge amount to the second preset charge amount, a second lower limit value and a second upper limit value of the refrigerant charge amount are determined; The optimal refrigerant charge of the rear air conditioner is calculated based on the second lower limit, the second upper limit, and the optimal charge calculation formula. The formula for calculating the optimal refrigerant charge is: MO = ML + 0.75 × (MU - ML), where MO represents the optimal refrigerant charge; when calculating the optimal refrigerant charge of the front air conditioner, ML represents the first lower limit value; MU represents the first upper limit value; when calculating the optimal refrigerant charge of the rear air conditioner, ML represents the second lower limit value; MU represents the second upper limit value.

[0014] According to some embodiments of the present invention, the sensor includes a first sensor, a second sensor, a third sensor, a fourth sensor, and a fifth sensor, and the installation of the sensor on the test vehicle includes: The first sensor is installed at the front of the test vehicle, at the center height of the front of the test vehicle, to obtain the ambient temperature; The second sensor is installed at the air outlet of the test vehicle to obtain the air outlet temperature of the test vehicle. The third sensor is installed at the head of the passenger compartment of the test vehicle to obtain the temperature at the head of the passenger compartment. The fourth sensor is installed at the refrigerant outlet of the indoor heat exchanger of the front air conditioner and the rear air conditioner to obtain the outlet temperature of the indoor heat exchanger. The fifth sensor is installed at the refrigerant outlet of the indoor heat exchanger of the front air conditioner and the rear air conditioner to obtain the outlet pressure of the indoor heat exchanger.

[0015] According to the second aspect of the present invention, a refrigerant charge system for a dual independent air conditioning system is applicable to the test method for the refrigerant charge of a dual independent air conditioning system described in the above embodiments, the charge system comprising: An environmental chamber for housing test vehicles, wherein the environmental chamber is configured to have an adjustable interior temperature to achieve a set temperature; The charging device is configured to charge the refrigerant into the rear air conditioner according to the theoretical charging amount and to perform vacuuming on the refrigerant pipeline of the front air conditioner. Start the test vehicle and turn on the front air conditioner and the rear air conditioner. Start charging the front air conditioner with refrigerant from the initial charge amount and gradually increase the charge amount until the first preset charge amount is reached. Calculate the optimal charge amount of refrigerant for the front air conditioner based on the charge range from the initial charge amount to the first preset charge amount. The refrigerant lines of the rear air conditioner are evacuated, and the test vehicle is restarted. The front and rear air conditioners are then turned on. Refrigerant is introduced into the rear air conditioner starting from the initial charge amount, and the charge amount is gradually increased until the second preset charge amount is reached. The optimal charge amount of refrigerant for the rear air conditioner is calculated based on the charge range from the initial charge amount to the second preset charge amount.

[0016] The refrigerant charging system for a dual independent air conditioning system according to an embodiment of the present invention has at least the following beneficial effects: The refrigerant charging system places the test vehicle in an environmental chamber, which regulates the indoor temperature to a set level. The charging device first charges the rear air conditioner with refrigerant according to the theoretical charge amount, and then evacuates the refrigerant lines of the front air conditioner. After starting the test vehicle and turning on both the front and rear air conditioners, refrigerant is charged into the front air conditioner starting from the initial charge amount, gradually increasing the charge until a first preset charge amount is reached. Then, based on the charge range from the initial charge amount to the first preset charge amount, the optimal refrigerant charge amount for the front air conditioner is calculated. After determining the optimal refrigerant charge amount for the front air conditioner, the test system is shut down. The vehicle undergoes a vacuum process to evacuate the refrigerant piping of the rear air conditioner. The test vehicle is then restarted, and both the front and rear air conditioners are turned on. Refrigerant is then added to the rear air conditioner starting from the initial charge amount, gradually increasing the charge amount until a second preset charge amount is reached. Based on the charge range from the initial charge amount to the second preset charge amount, the optimal refrigerant charge amount for the rear air conditioner is calculated. This method accurately calculates the optimal refrigerant charge amounts for both the front and rear air conditioners with high accuracy. It is suitable for hybrid buses with dual independent air conditioning systems and provides an important reference for confirming the charge amount of dual independent air conditioning systems, reducing the risk of refrigerant charging failure.

[0017] According to a third aspect of the present invention, the control device includes at least one processor; and a memory storing instructions that, when executed by the at least one processor, perform the test method for refrigerant charge quantity of the dual independent air conditioning system described in the first aspect of the present invention.

[0018] Since the control device adopts all the technical solutions of the test method for refrigerant charge of the dual independent air conditioning system in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments, which will not be repeated here.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a dual independent air conditioning system according to an embodiment of the present invention; Figure 2 This is a flowchart of a test method for refrigerant charge amount in a dual independent air conditioning system according to an embodiment of the present invention; Figure 3 This is a flowchart of the refrigerant charging steps for a front air conditioner according to an embodiment of the present invention; Figure 4 This is a flowchart of the refrigerant charging steps for a rear air conditioner according to an embodiment of the present invention; Figure 5 This is an example table of measurement parameters and sensor installation locations in one embodiment of the present invention; Figure 6 This is a test condition table for determining the refrigerant charge of an air conditioner in one embodiment of the present invention; Figure 7 This is a coordinate graph showing the trend of subcooling and charge amount during the refrigerant charging process in one embodiment of the present invention; Figure 8 This is an example table of subcooling calculation results for a front air conditioner in one embodiment of the present invention; Figure 9 This is an example table of subcooling calculation results for the rear air conditioner in one embodiment of the present invention; Figure 10 This is a graph showing the subcooling of the front air conditioner, the temperature of the air outlet, and the high pressure of the air conditioning system as a function of the charge amount in one embodiment of the present invention. Figure 11 This is a graph showing the changes in subcooling of the rear air conditioning system, air outlet temperature, and high pressure of the air conditioning system with the amount of charge in one embodiment of the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this invention, it should be noted that terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0026] Hybrid buses offer significant advantages in energy conservation, emission reduction, and operating costs, leading to their widespread adoption in urban public transportation. However, due to the large size of these buses and the resulting difficulties in refrigerant flow distribution, some have adopted dual independent air conditioning systems. Yet, directly applying the refrigerant charging methods of traditional single-air conditioning systems to dual-air conditioning systems fails to accurately determine the refrigerant charge, resulting in uneven refrigerant distribution and increased risk of battery overheating. Particularly in high-temperature summer conditions, improper refrigerant flow control during simultaneous operation of the front and rear air conditioners can easily lead to decreased system efficiency or component damage.

[0027] To address the aforementioned issues, the inventors discovered that the independent operation of dual air conditioning systems renders traditional charging methods ineffective. Analysis revealed that a uniform charging method cannot accurately assess the optimal operating state of each system. Therefore, a phased independent testing scheme was proposed. While testing the refrigerant charge of one air conditioning system, the normal operation of the other system is ensured. This invention provides a testing method for the refrigerant charge of dual independent air conditioning systems, applicable to hybrid buses with dual independent air conditioning systems. This method effectively improves the accuracy of test results and provides an important reference for confirming the refrigerant charge of dual independent air conditioning systems.

[0028] Reference Figure 2 As shown, this embodiment of the invention provides a test method for the refrigerant charge of a dual independent air conditioning system, including the following steps: Step S100: Install sensors on the test vehicle and calibrate the sensors; Step S200: Place the test vehicle in the environmental chamber and adjust the temperature inside the environmental chamber to reach the set temperature. Step S300: Charge the refrigerant into the rear air conditioner according to the theoretical charge amount, and perform vacuuming on the refrigerant pipeline of the front air conditioner. Step S400: Start the test vehicle and turn on the front and rear air conditioners. Start charging the front air conditioner with refrigerant from the initial charge amount and gradually increase the charge amount until the first preset charge amount is reached. Step S500: Calculate the optimal refrigerant charge for the front air conditioner based on the refrigerant charge range from the initial charge amount to the first preset charge amount. Step S600: Vacuum the refrigerant lines of the rear air conditioner, restart the test vehicle, and turn on both the front and rear air conditioners. Step S700: Refrigerant is charged into the air conditioner starting from the initial charge amount, and the charge amount is gradually increased until the second preset charge amount is reached; Step S800: Calculate the optimal refrigerant charge for the rear air conditioner based on the refrigerant charge range from the initial charge amount to the second preset charge amount.

[0029] Reference Figure 1As shown, the test vehicle used in the proposed test method is a hybrid bus, which includes a dual independent air conditioning system. Specifically, this system comprises a front air conditioner and a rear air conditioner. The front air conditioner is installed at the front of the test vehicle, and the rear air conditioner is installed at the rear. Sensors are installed on the test vehicle. These sensors may include pressure sensors, temperature sensors, or other data acquisition sensors. The pressure sensor is used to detect the pressure in the refrigerant lines of the front and rear air conditioners, and the temperature sensor is used to detect the air outlet temperature and ambient temperature inside the vehicle. Taking the pressure and temperature sensors as examples, after installation, the pressure and temperature sensors are calibrated to ensure the accuracy of data acquisition.

[0030] In this embodiment, the test vehicle is placed inside an environmental chamber. The temperature inside the chamber is stabilized within a set range by a constant temperature control system, for example, by using a PID control algorithm to adjust the heating and cooling modules. Sensor calibration involves zero-point drift correction and range calibration of the temperature and pressure sensors. Testing the vehicle inside the environmental chamber allows for more accurate simulation of real-world temperatures, improving test accuracy. In some embodiments, the temperature inside the environmental chamber is set to 40°C, and after stabilization, the temperature range within the chamber is ensured to be 40°C ± 1°C.

[0031] Reference Figure 1 As shown, the front and rear air conditioners are understood to be independent air conditioning systems. Each system includes a compressor, indoor heat exchanger, outdoor heat exchanger, and a throttling device. These components form a refrigerant circulation loop, and the refrigerant charge can be understood as the refrigerant capacity within that loop. In cooling mode, the outdoor heat exchanger acts as a condenser, and the indoor heat exchanger as an evaporator; in heating mode, the outdoor heat exchanger acts as an evaporator, and the indoor heat exchanger as a condenser. During operation, the front and rear air conditioners work independently. Therefore, the testing method requires separate testing of the front and rear air conditioners. When testing the refrigerant charge of one system, it is essential to ensure the other system is operating normally to accurately determine the optimal refrigerant charge for each.

[0032] In step S300 above, refrigerant is charged into the rear air conditioner according to the theoretical charge amount, and the refrigerant pipeline of the front air conditioner is evacuated. The theoretical charge amount can be understood as the amount of refrigerant required for the rear air conditioner to operate normally. The evacuation process involves using a vacuum pump to reduce the pipeline pressure to below a set threshold, for example, below 50 Pa, and maintaining this pressure for 10 minutes to eliminate the influence of residual refrigerant and ensure accurate measurement of the refrigerant charge amount.

[0033] After charging the rear air conditioner with refrigerant, start the test vehicle and simultaneously turn on both the front and rear air conditioners. At this point, the rear air conditioner is in normal operating condition. Begin charging the front air conditioner with refrigerant starting from the initial charge amount, gradually increasing the charge amount until the first preset charge amount is reached. In other words, a staged charging mode is used: first, the initial charge amount is added, and then the charge amount is increased each time, with the increase being proportional to a set percentage, for example, 5%-10% of the theoretical value each time. This charging process is repeated multiple times until the total charge amount in the front air conditioner reaches the first preset charge amount.

[0034] During the continuous charging test, the optimal refrigerant charge of the air conditioner can be calculated based on the charging range of the refrigerant from the initial charge amount to the first preset charge amount. The calculation of the optimal charge amount can be based on the identification of the inflection point of system performance within the charging range, for example, by determining the critical point through the change in the slope of the refrigeration efficiency curve.

[0035] After determining the optimal charge amount for the front air conditioner, steps S600 to S800 are performed to measure the optimal charge amount for the rear air conditioner. The specific principle is similar to that of steps S300 to S500. Specifically, since the optimal charge amount for the front air conditioner has been determined, charging the front air conditioner with refrigerant according to the optimal charge amount ensures that the front air conditioner can operate stably.

[0036] The refrigerant lines of the rear air conditioner were evacuated, and the test vehicle was restarted. Both the front and rear air conditioners were simultaneously turned on, with the front air conditioner operating normally. Refrigerant was then added to the rear air conditioner starting with the initial charge amount, gradually increasing the charge until the second preset charge amount was reached. The rear air conditioner was also charged using a tiered charging method: the initial charge amount was added first, followed by an increase in charge amount each time, which could be proportional to a set increment, for example, 5%-10% of the theoretical value each time. This process was repeated multiple times until the total charge amount of the rear air conditioner reached the second preset charge amount.

[0037] During the continuous charging test, the optimal refrigerant charge of the air conditioner can be calculated based on the charging range of the refrigerant from the initial charge amount to the second preset charge amount. The calculation of the optimal refrigerant charge of the air conditioner can also be based on the identification of the inflection point of system performance within the charging range, for example, by determining the critical point through the change in the slope of the refrigeration efficiency curve.

[0038] The above-described test method, applied to dual independent air conditioning systems, allows for a more realistic simulation of actual usage scenarios. This enables a more accurate determination of the optimal refrigerant charge for both the front and rear air conditioners, providing a crucial reference for refrigerant charge verification tests on dual independent air conditioning systems. It also reduces the risk of refrigerant charging failures and is particularly suitable for hybrid buses with dual independent air conditioning systems, addressing the issues of test failures and inaccurate results caused by the complexity of dual air conditioning systems.

[0039] Understandably, traditional methods only design charging procedures for single air conditioning systems and cannot solve the dynamic refrigerant balance problem when operating dual air conditioning systems. This invention, through a time-sharing isolation testing mechanism, effectively eliminates mutual interference between dual air conditioning systems. During the charging process, it monitors key node pressure parameters in real time, ensuring that each air conditioner determines its optimal charging amount under independent optimization. Furthermore, the step-by-step independent testing process avoids refrigerant distribution imbalances caused by simultaneous charging of both air conditioning systems, ensuring that both the front and rear air conditioners operate at their optimal efficiency points and effectively preventing battery overheating failures due to improper charging.

[0040] In some embodiments, the front air conditioner is charged in stages starting from an initial charge amount, with the heat exchanger outlet pressure monitored after each charge. Charge is stopped when the pressure reaches a preset threshold, and the charge amount at this point is recorded as the upper limit. Based on the range between the initial charge amount and the upper limit, the optimal charge amount is calculated using a linear interpolation formula. After optimizing the front air conditioner, the rear air conditioner piping is evacuated, and the same process is repeated to ultimately obtain the optimal charge parameters for each of the two air conditioning systems independently.

[0041] Reference Figure 3 As shown, step S400 above specifically includes, but is not limited to, the following steps: Step S410: Charge the refrigerant into the front air conditioner according to the initial charge amount, and then charge it multiple times in succession, increasing the charge amount each time. Step S420: Obtain the outlet pressure value of the indoor heat exchanger of the front air conditioner; Step S430: When the outlet pressure of the indoor heat exchanger is greater than or equal to the first preset pressure value, determine that the current refrigerant charge of the front air conditioner is the first preset charge, and control to stop injecting refrigerant into the front air conditioner.

[0042] The initial charge amount is the difference between the theoretical charge amount and the preset charge amount. Specifically, it can be determined by subtracting a fixed value from the theoretical value. For example, if the theoretical value is 500g, the preset charge amount could be 200g, and the initial charge amount would be 300g. Multiple continuous charges with progressively increasing charge amounts can be understood as gradually increasing the charge amount in fixed increments each time, such as increasing by 50g each time. This staged charging achieves precise control of the charge amount. The first preset charge amount can be a charge termination threshold determined by pressure monitoring. The first preset charge amount for the current air conditioner could be 700g, 800g, etc. For example, when the current air conditioner's charge amount reaches 700g, the indoor heat exchanger outlet pressure reaches 2.5MPa, triggering a stop command. This threshold can be preset according to the system design parameters.

[0043] Specifically, during the charging process, the initial charging amount is first determined based on the difference between the theoretical value and the preset amount. Then, the charging is done in multiple increments, for example, 50g each time, while the outlet pressure of the indoor heat exchanger of the front air conditioner is monitored in real time. When the pressure reaches a preset threshold, such as 2.5MPa, it is determined that the charging amount has reached the first preset amount, and charging stops at this point. This process, through the combination of staged incremental charging and a pressure feedback mechanism, achieves dynamic adjustment of the charging amount, avoiding abnormal system pressure caused by a single overcharging.

[0044] Understandably, traditional methods typically employ single-charge or fixed-increment refrigerant addition, lacking a dynamic control mechanism based on pressure feedback, which can easily lead to refrigerant charge deviations. However, this invention, through preset initial charge, phased incremental refrigerant addition, and pressure threshold determination, forms a closed-loop control logic. This makes the refrigerant charge adjustment process more precise and controllable, effectively solving the problem of inaccurate refrigerant charge control in dual independent air conditioning systems. Through the synergistic effect of phased incremental refrigerant addition and pressure feedback, it ensures that the charge meets cooling requirements while avoiding system pressure anomalies caused by overcharging, thereby improving the operational stability of dual air conditioning systems.

[0045] In some embodiments, the pressure of the heat exchanger is used to determine whether the first preset charge amount has been reached. Specifically, the outlet pressure value of the indoor heat exchanger of the front air conditioner is obtained. When the outlet pressure value of the indoor heat exchanger is greater than or equal to the first preset pressure value, the current refrigerant charge amount of the front air conditioner is determined to be the first preset charge amount, and the injection of refrigerant into the front air conditioner is stopped.

[0046] The outlet pressure of the indoor heat exchanger is the pressure parameter formed at the outlet of the indoor heat exchanger after the refrigerant flows through it. This pressure can be monitored in real time using a pressure sensor installed at the outlet pipe of the heat exchanger. The first preset pressure value can be understood as a pressure threshold pre-set based on the air conditioning system design parameters or experimental data. Specifically, it can be determined by comprehensively considering the compressor performance curve, refrigerant properties, and system operating conditions. This pressure threshold characterizes the critical point at which the refrigerant charge reaches the system's optimal operating state.

[0047] Specifically, during the gradual charging of refrigerant into the air conditioner, a pressure sensor continuously collects the outlet pressure data of the indoor heat exchanger. When the detected pressure rises to equal or exceed a first preset pressure value, it indicates that the charging amount has met the operating requirements of the air conditioning system. At this point, the charging operation is immediately terminated to avoid overcharging, which could lead to excessive compressor load or decreased system efficiency. For example, when using R134a refrigerant, the first preset pressure value can be set to the pressure value corresponding to a saturation temperature of 40°C, specifically within the range of 2.0 MPa to 2.5 MPa.

[0048] Understandably, traditional methods typically rely on fixed charge amounts or empirical values ​​to determine the charging endpoint, failing to dynamically respond to the actual operating status of the system. However, this invention, by monitoring the outlet pressure parameters of the heat exchanger in real time, accurately reflects the dynamic balance between refrigerant charge and system pressure, thereby precisely determining the optimal charge amount. Through this technical solution, this invention achieves precise control of the refrigerant charge, effectively preventing increased compressor power consumption or reduced system efficiency due to overcharging, while also avoiding a decrease in cooling effect caused by insufficient charging. This pressure criterion method can adapt to different ambient temperatures and system operating conditions, ensuring that each of the two independent air conditioning systems is in its optimal charging state when working collaboratively.

[0049] Reference Figure 4 As shown, step S700 above specifically includes, but is not limited to, the following steps: Step S710: Charge the refrigerant into the air conditioner according to the initial charge amount, and then charge it multiple times in succession, increasing the charge amount each time. Step S720: Obtain the outlet pressure value of the indoor heat exchanger of the rear air conditioner; Step S730: When the outlet pressure of the indoor heat exchanger is greater than or equal to the second preset pressure value, determine that the current refrigerant charge of the rear air conditioner is the second preset charge, and control to stop injecting refrigerant into the rear air conditioner.

[0050] In this embodiment, the initial charge amount of the rear air conditioner is the same as that of the front air conditioner. Specifically, it can be determined by subtracting a fixed value from the theoretical value. Continuous charging multiple times with progressively increasing charge amounts can be understood as gradually increasing the charge amount in fixed increments each time, for example, increasing the charge amount by 50g each time. This staged charging achieves precise control of the charge amount. The second preset charge amount can be a charge termination threshold determined by pressure monitoring. For example, a stop command is triggered when the outlet pressure of the indoor heat exchanger reaches 2.5MPa. This threshold can be preset according to the system design parameters.

[0051] In some embodiments, the pressure of the heat exchanger is used to determine whether the second preset charge amount has been reached. Specifically, the outlet pressure value of the indoor heat exchanger of the rear air conditioner is obtained. When the outlet pressure value of the indoor heat exchanger is greater than or equal to the second preset pressure value, the current refrigerant charge amount of the rear air conditioner is determined to be the second preset charge amount, and the injection of refrigerant into the rear air conditioner is stopped.

[0052] The outlet pressure of the indoor heat exchanger in the air conditioner is the pressure parameter formed at the outlet of the refrigerant after it flows through the indoor heat exchanger. This pressure can be monitored in real time using a pressure sensor installed at the outlet pipe of the heat exchanger. The second preset pressure value can be understood as a pressure threshold pre-set based on the air conditioning system design parameters or experimental data. Specifically, it can be determined by comprehensively considering the compressor performance curve, refrigerant properties, and system operating conditions. This pressure threshold characterizes the critical point at which the refrigerant charge reaches the system's optimal operating state.

[0053] Specifically, during the gradual charging of refrigerant into the air conditioner, pressure sensors continuously collect pressure data at the outlet of the indoor heat exchanger. When the detected pressure rises to equal or exceed a second preset pressure value, it indicates that the charging amount has met the operating requirements of the air conditioning system. At this point, the charging operation is immediately terminated to prevent overcharging, which could lead to excessive compressor load or decreased system efficiency.

[0054] Understandably, traditional methods typically rely on fixed charge amounts or empirical values ​​to determine the charging endpoint, failing to dynamically respond to the actual operating status of the system. However, this invention, by monitoring the outlet pressure parameters of the heat exchanger in real time, accurately reflects the dynamic balance between refrigerant charge and system pressure, thereby precisely determining the optimal charge amount. Through this technical solution, this invention achieves precise control of the refrigerant charge, effectively preventing increased compressor power consumption or reduced system efficiency due to overcharging, while also avoiding a decrease in cooling effect caused by insufficient charging. This pressure criterion method can adapt to different ambient temperatures and system operating conditions, ensuring that each of the two independent air conditioning systems is in its optimal charging state when working collaboratively.

[0055] This invention further proposes charging the air conditioner with refrigerant according to the theoretical charge amount, which is calculated using the following formula: Q = (Vcomp + Vcond + Vevap + Vpipe). ρ, where Q represents the theoretical value of refrigerant charge, Vcomp represents the internal volume of the compressor, Vcond represents the internal volume of the condenser, Vevap represents the internal volume of the evaporator, Vpipe represents the internal volume of the piping, and ρ is the saturated liquid density of the refrigerant at a temperature of 40℃.

[0056] The compressor internal volume, measured in m³, refers to the space inside the compressor that can hold refrigerant. This volume can be obtained using the compressor's factory parameters or by measuring through 3D modeling, and reflects the compressor's refrigerant requirements. The condenser internal volume, measured in m³, refers to the effective internal volume of the condenser's piping. This volume can be determined through geometric measurement or fluid displacement methods, and characterizes the refrigerant storage space during the condensation stage. The evaporator internal volume, measured in m³, refers to the effective internal volume of the evaporator. This volume can be obtained through structural parameter calculations or experimental calibration, and measures the refrigerant capacity requirements during the evaporation stage. The refrigerant piping internal volume, measured in m³, refers to the internal volume of the pipes connecting various components of the air conditioning system. This volume can be calculated by multiplying the pipe length by its cross-sectional area, and is used to compensate for the amount of refrigerant retained in the piping. The saturated liquid density of the refrigerant refers to the density value of the refrigerant in its liquid state at a standard temperature of 40°C. This density can be obtained by consulting a property table or through experimental measurement, and is used to convert volume parameters into mass parameters.

[0057] Specifically, when determining the theoretical charge quantity, the internal volumes of the compressor, condenser, evaporator, and piping are first measured. For example, 3D scanning technology can be used to obtain internal structural data of the compressor, or the evaporator volume can be measured using the water injection method. Then, the volumes of each component are substituted into the formula and summed, multiplied by the refrigerant's saturated liquid density at 40°C. For example, the density of R134a refrigerant at this temperature is approximately 1205 kg / m³. This calculation method yields a theoretical charge quantity benchmark based on the system's physical structure, providing a scientific basis for subsequent charge tests. In actual operation, this theoretical value can be used as an initial reference value and dynamically adjusted based on pressure monitoring data during the charge process.

[0058] Through the above technical solution, this invention solves the technical problem of lacking theoretical calculation basis for refrigerant charge in dual independent air conditioning systems. By establishing a multi-component collaborative calculation model, it ensures that the calculated theoretical charge value matches the actual system requirements. This method provides an accurate benchmark value for subsequent charging tests, avoiding repeated adjustments due to initial charge deviations, and reducing the risk of system efficiency degradation caused by insufficient or excessive refrigerant.

[0059] In some embodiments, step S500 above, calculating the optimal refrigerant charge for the front air conditioner based on the refrigerant charge range from the initial charge amount to the first preset charge amount, specifically includes the following steps: Step S510: Based on the refrigerant charging process from the initial charge amount to the first preset charge amount, determine the first lower limit and the first upper limit of the refrigerant charge amount; Step S520: Calculate the optimal refrigerant charge for the front air conditioner based on the first lower limit, the first upper limit, and the optimal charge calculation formula.

[0060] In step S800 above, the optimal refrigerant charge for the air conditioner is calculated based on the refrigerant charge range from the initial charge amount to the second preset charge amount. This specifically includes the following steps: Step S810: Based on the refrigerant charging process from the initial charge amount to the second preset charge amount, determine the second lower limit value and the second upper limit value of the refrigerant charge amount; Step S820: Calculate the optimal refrigerant charge for the rear air conditioner based on the second lower limit, the second upper limit, and the optimal charge calculation formula.

[0061] It should be noted that the optimal refrigerant charge calculation formula in the embodiment is: MO = ML + 0.75 × (MU - ML), where MO represents the optimal refrigerant charge; ML represents the lower limit of the charge; and MU represents the upper limit of the charge. For example, when calculating the optimal refrigerant charge for the front air conditioner, ML represents the first lower limit of the charge; and MU represents the first upper limit of the charge. The optimal refrigerant charge for the front air conditioner can be calculated according to the above formula. When calculating the optimal refrigerant charge for the rear air conditioner, ML represents the second lower limit of the charge; and MU represents the second upper limit of the charge. The optimal refrigerant charge for the rear air conditioner can be calculated according to the above formula.

[0062] The first and second preset charge amounts can be experimentally determined upper limit thresholds for the charge amount. Specifically, this can be determined by monitoring the heat exchanger outlet pressure to reach a preset pressure value. For example, charging can be stopped when the pressure exceeds the set threshold, thus ensuring the system operates within a safe range. The optimal charge amount calculation formula MO = ML + 0.75 × (MU - ML) refers to determining the optimal value based on the linear relationship between the upper and lower limits of the charge amount. Specifically, this can be achieved by selecting a specific percentage point within the charge range as the optimal value, for example, by verifying through multiple experiments that the system energy efficiency reaches its peak at this percentage.

[0063] Specifically, during the charging process, the initial charge amount serves as the starting point for the test. By gradually increasing the refrigerant charge and monitoring system performance parameters, such as heat exchanger outlet pressure and temperature, the effective range of the charge amount is determined. When the charge amount reaches the lower limit, the system begins to produce an effective cooling effect; when the charge amount reaches the upper limit, the system pressure approaches the safety threshold. By recording the impact of charge amount changes within this range on the cooling efficiency, and using the formula MO = ML + 0.75 × (MU - ML), the optimal charge amount that balances system performance and stability can be calculated. For example, if the lower limit for the air conditioner is measured to be 1.2 kg and the upper limit to be 1.8 kg, then the optimal charge amount is 1.2 + 0.75 × (1.8 - 1.2) = 1.65 kg.

[0064] Existing single-air conditioning systems typically determine the charge volume using fixed empirical values ​​or a single test point. This solution, however, dynamically tests the charge range and calculates the optimal value using mathematical formulas, enabling more precise adaptation to the complex operating conditions of dual independent air conditioning systems. For example, traditional methods might estimate the charge volume solely based on compressor volume, while this solution effectively avoids charge errors caused by differences in piping layout or environmental changes by actually testing the upper and lower limits and introducing a proportional coefficient.

[0065] Through the above technical solution, this invention can accurately determine the optimal refrigerant charge for the front and rear air conditioners in a dual independent air conditioning system, solving the problems of reduced energy efficiency or battery overheating caused by uneven refrigerant distribution in the dual air conditioning system. For example, through dynamic testing and formula calculation, it can avoid the rear air conditioner from being under-charged due to overcharging of the front air conditioner, or the compressor from being under-charged due to insufficient cooling, thereby improving the overall operational stability and cooling efficiency of the system.

[0066] This invention further proposes a sensor installation method, wherein the sensors include a first sensor, a second sensor, a third sensor, a fourth sensor, and a fifth sensor. When installing the sensors on the test vehicle, the first sensor is installed at the front of the test vehicle, at the center height of the front fascia, to obtain the ambient temperature; the second sensor is installed at the air vent inside the test vehicle to obtain the outlet air temperature; the third sensor is installed at the head of the passenger compartment to obtain the head temperature inside the compartment; the fourth sensor is installed at the refrigerant outlet of the indoor heat exchanger of the front and rear air conditioners to obtain the outlet temperature; and the fifth sensor is installed at the refrigerant outlet of the indoor heat exchanger of the front and rear air conditioners to obtain the outlet pressure.

[0067] The system comprises five sensors: The first sensor is a temperature sensor used to monitor the external ambient temperature of the vehicle. This can be implemented using a thermocouple or a thermistor. Its installation position at the center of the front of the vehicle avoids direct sunlight and interference from localized heat sources, ensuring accurate ambient temperature data. The second sensor measures the temperature of the air conditioning vents. This can be implemented using a patch-type temperature probe and is installed at the vents to reflect the real-time impact of the air conditioning's cooling effect on the interior temperature. The third sensor monitors the temperature in the head area of ​​the passenger compartment. This can be implemented using a suspended temperature sensor and is installed at the head position to assess passenger comfort and the air conditioning system's ability to regulate the cabin temperature distribution. The fourth sensor detects the refrigerant temperature at the heat exchanger outlet. This can be implemented using a high-pressure resistant temperature sensor and is installed at the outlet to obtain information about the heat exchange state of the refrigerant within the heat exchanger. The fifth sensor measures the refrigerant pressure at the heat exchanger outlet. This can be implemented using a piezoelectric pressure sensor and is installed at the outlet to monitor pressure changes in the refrigerant circulation system.

[0068] Specifically, the first sensor is installed at the center height of the front of the test vehicle to accurately reflect the ambient temperature and avoid temperature measurement distortion caused by installation position deviation. The second sensor at the air vent is mounted inside the air duct using a fixed bracket, ensuring full contact between the probe and the airflow to record the impact of refrigerant charge changes on the outlet temperature in real time. The third sensor at the head of the passenger compartment is fixed to the cabin roof liner using an adjustable clamp, its height level with the passenger's head, and is used to evaluate the air conditioning system's temperature control effect on the passenger activity area. The fourth and fifth sensors are installed on the refrigerant outlet pipes of the front and rear air conditioner interior heat exchangers using dedicated interfaces. The temperature and pressure sensors are installed in parallel, with sealed connections ensuring pipe sealing, and simultaneously collecting outlet temperature and pressure data to provide key parameters for calculating the refrigerant charge.

[0069] Traditional methods typically use only a single pressure sensor in the air conditioning duct, failing to comprehensively monitor ambient temperature, outlet air temperature, cabin temperature distribution, and heat exchanger operating status. Furthermore, the sensor placement lacks systematic planning; for example, an ambient temperature sensor might be installed on the side of the vehicle, causing measurements to be affected by localized airflow, or a cabin temperature sensor placed in the foot area might not reflect actual passenger comfort. This solution, through the coordinated arrangement of five sensors, constructs a multi-dimensional monitoring network covering environmental parameters, air conditioning output, passenger experience, and system operating status. In particular, grouping the pressure and temperature sensors at the heat exchanger outlet allows for precise determination of the refrigerant's phase change state during heat exchange.

[0070] Through the above technical solution, this invention achieves comprehensive monitoring of the operating status of a dual air conditioning system, providing a reliable basis for refrigerant charge calculation through multi-dimensional data acquisition. Simultaneous monitoring of ambient temperature and outlet air temperature can assess the cooling efficiency of the air conditioning system under different operating conditions; cabin head temperature measurement directly reflects passenger comfort; and the combined data of heat exchanger outlet temperature and pressure can accurately determine whether the refrigerant charge has reached its optimal state. This arrangement effectively avoids misjudgments of charge caused by the incompleteness of data from a single sensor, ensuring that the optimized charge calculations for both the front and rear air conditioners when operating independently are based on complete system status information.

[0071] The following example illustrates the test method for refrigerant charge of the aforementioned dual independent air conditioning system.

[0072] The test method in the embodiment includes three parts: vehicle inspection and preparation, environmental chamber setting, and whole vehicle bench test.

[0073] The verification preparation steps include: in addition to meeting the requirements of GB / T 12534, the test vehicle shall also meet the following requirements: vehicle system integrity check, system cleaning and drying, refrigerant type and quality verification, test equipment calibration, environmental condition control and system initial state check.

[0074] Vehicle system integrity checks include the following: Component Installation Correctness Check: Ensure all components of the air conditioning system (such as compressor, condenser, evaporator, expansion valve, etc.) are correctly installed and securely connected, without looseness or leaks. Piping Sealing Check: Inspect refrigerant piping and connections to ensure no leaks and prevent refrigerant loss or outside air entering the system. Electrical Connection Reliability Check: Inspect electrical wiring and control system connections to ensure no short circuits, open circuits, or poor contact. Air Conditioning Supply Piping Unobstructed: Confirm all air supply duct interfaces are leak-free and all air outlet valves operate smoothly. Operating System Reliability Check: Confirm temperature control switches, airflow control switches, airflow direction selection switches, and internal / external circulation control switches are operating normally. Vehicle Sealing and Software Integrity Check: Ensure the vehicle's airtightness meets the vehicle's technical requirements and confirm the vehicle software strategy has reached its final development state.

[0075] System cleaning and drying includes the following: ensuring the system is free of impurities, oil, or other contaminants to prevent blockages or impaired refrigerant flow. A thorough vacuum is then performed to ensure no moisture remains, preventing the reaction of moisture with the refrigerant to form acidic substances that could corrode system components.

[0076] Refrigerant type and quality verification includes the following: ensuring that the type of refrigerant used is consistent with the system design requirements (e.g., R134a, R1234yf, etc.). Using high-purity, uncontaminated refrigerants is crucial to avoid affecting test results due to refrigerant quality issues.

[0077] The calibration of the test equipment includes the following: calibrating pressure sensors, temperature sensors, and measuring devices to ensure the accuracy of data acquisition; and ensuring the accuracy of the refrigerant charging equipment to avoid charging errors.

[0078] Environmental condition control includes the following: ensuring that the environmental simulation device can accurately simulate the environmental conditions required for the test; ensuring that the test environment is free from external interference, such as strong winds or direct sunlight; removing any camouflage materials in the front area of ​​the vehicle and inside the engine compartment that may affect or change the temperature inside the engine compartment; and ensuring that the air intake volume and direction at the front of the vehicle are consistent with the design.

[0079] The initial system condition check includes the following: Before charging refrigerant, check the system pressure to ensure the system is in normal condition. Confirm that the compressor can start and run normally without abnormal noise or vibration.

[0080] See Figure 5 As shown, Figure 5 The measurement parameters and sensor installation locations are shown in the diagram.

[0081] In some embodiments, the setup of the environmental chamber includes the following steps: setting the ambient temperature to 40°C, and ensuring that the temperature inside the experimental chamber is controlled at 40°C ± 1°C after the temperature stabilizes.

[0082] In some embodiments, the whole vehicle bench test includes the following steps: Step 10: Vacuum the front and rear air conditioners.

[0083] Step 20: The theoretical value of the refrigerant charge is then added to the air conditioner.

[0084] Step 30: Start the vehicle and turn on the front and rear air conditioners. Begin charging the front air conditioner with refrigerant starting at an initial charge amount M1 via the low-pressure line, increasing by 25g each time, continuing until the final charge amount Mx is reached. Here, the initial charge amount M1 is the theoretical refrigerant charge amount minus 300g; the final charge amount Mx is the charge amount corresponding to when the refrigerant outlet pressure of the indoor condenser begins to exceed 2.5MPa during the continuous charge test.

[0085] Reference Figure 6 As shown, Figure 6 The test conditions for determining the refrigerant charge of an air conditioner are shown.

[0086] Reference Figure 7 As shown, a graph depicting the relationship between subcooling and charge quantity is plotted with charge quantity as the X-axis and subcooling as the Y-axis. The lower limit ML and upper limit MU of the refrigerant charge quantity at low temperatures are determined.

[0087] Step 40: Calculate and determine the refrigerant charge range. The optimal refrigerant charge for air conditioning is MO, which is calculated using the following formula: MO = ML + 0.75 × (MU - ML) In the formula: MO is the optimal charge volume; ML is the lower limit of the charge volume; MU is the upper limit of the charge volume.

[0088] Step 50: Charge the front air conditioner with the optimal amount of refrigerant.

[0089] Step 60: Repeat steps 30 and 40 above to confirm the optimal refrigerant charge for the air conditioner.

[0090] Reference Figure 8 and Figure 9 As shown, when the front air conditioner reached a charge of 750g, the high-pressure end pressure of the air conditioning system rose to 2.5MPa, and the test ended. When the rear air conditioner reached a charge of 1150g, the high-pressure end pressure of the air conditioning system rose to 2.5MPa, and the test ended.

[0091] Reference Figure 10 and Figure 11 As shown, Figure 10 The curves showing the changes in subcooling of the front air conditioning system, air outlet temperature, and high pressure of the air conditioning system with the charge amount are shown. Figure 11 The curves showing the changes in subcooling of the rear air conditioning system, air outlet temperature, and high pressure of the air conditioning system with the charge amount are presented.

[0092] This invention provides a refrigerant charging system for a dual independent air conditioning system, comprising an environmental chamber and a charging device. The environmental chamber is used to house a test vehicle, and its interior temperature can be adjusted to reach a set temperature. The charging device is configured to charge refrigerant into the rear air conditioner according to the theoretical charging amount, and to evacuate the refrigerant lines of the front air conditioner. The test vehicle is started and both the front and rear air conditioners are turned on. Refrigerant is charged into the front air conditioner starting from the initial charging amount and gradually increased to a first preset charging amount, and the optimal charging amount for the front air conditioner is calculated. After evacuating the rear air conditioner lines, the vehicle and air conditioner are restarted. Refrigerant is charged into the rear air conditioner starting from the initial charging amount and gradually increased to a second preset charging amount, and the optimal charging amount for the rear air conditioner is calculated.

[0093] The environmental chamber refers to a sealed test space capable of simulating different temperature conditions. Specifically, it can be implemented using a temperature-controlled chamber with a temperature control module, adjusting the temperature inside the chamber to maintain the test vehicle under target operating conditions. The refrigerant charging device refers to equipment with refrigerant charging and pipeline vacuuming functions. Specifically, it can be implemented using an automatic refrigerant charging machine with a vacuum pump and metering valve, achieving staged charging through precise control of the charging amount. The optimal charging amount calculation refers to the process of calculating the optimal amount based on the upper and lower limits determined within the charging range, using a formula. Specifically, a preset algorithm module can process sensor data and automatically generate the result using the formula MO=ML+0.75×(MU-ML).

[0094] Specifically, after the test vehicle was placed in the environmental chamber, the temperature inside was adjusted to the target value to simulate actual operating conditions. The refrigerant charging device first charged the rear air conditioner with the theoretically calculated amount of refrigerant, while simultaneously evacuating the front air conditioner piping to remove residual gas. After the vehicle was started, both air conditioners operated simultaneously. The front air conditioner was charged in stages, starting from the initial charge amount, with each stage increasing by a fixed increment until the first preset amount was reached. During this process, the heat exchanger outlet pressure was monitored by sensors to determine the charging endpoint. Based on the charging range from the initial amount to the first preset amount, the upper and lower limits were determined, and the optimal charge amount for the front air conditioner was calculated using a formula. Subsequently, the rear air conditioner piping was evacuated and the system was restarted, and the staged charging process was repeated to determine the optimal charge amount for the rear air conditioner.

[0095] Traditional single-air conditioning system charging methods cannot handle the refrigerant distribution problem when dual air conditioning systems operate independently. Existing technologies lack a step-by-step processing mechanism for dual air conditioners, easily leading to uneven refrigerant distribution or system pressure imbalance. This solution uses an environmental chamber to precisely control test conditions, employing staged charging and independent vacuuming operations to ensure that the charging processes of the front and rear air conditioners do not interfere with each other. Simultaneously, pressure monitoring and formula calculations achieve precise matching of the charging amount for the dual air conditioning systems.

[0096] Through the above technical solution, this invention can accurately determine the optimal refrigerant charge for each unit in a dual independent air conditioning system, avoiding problems such as decreased cooling efficiency or battery overheating caused by charge deviation. The step-by-step design of the air conditioner charging process before and after processing effectively solves the technical challenge of refrigerant flow distribution in dual air conditioning systems, improving the operational reliability of the hybrid bus air conditioning system.

[0097] The present invention further proposes a control device, including at least one processor and a memory, the memory storing instructions, which, when executed by at least one processor, perform a test method for the refrigerant charge of a dual independent air conditioning system.

[0098] The processor, or processor, is a hardware unit capable of executing computer program instructions. It can be implemented using a central processing unit (CPU) or a microcontroller. It controls the test process for refrigerant charging, including starting the vehicle, adjusting the ambient chamber temperature, and controlling the charging device to perform vacuuming and charging operations. The memory, or memory medium, is used to store program instructions and data. It can be implemented using flash memory or a hard disk. It stores the execution logic of the test method and real-time data collected by sensors, ensuring the repeatability of the test process and the traceability of the data.

[0099] Specifically, the control unit executes instructions from its memory via a processor to automatically complete the refrigerant charge test for the dual independent air conditioning system. First, the ambient temperature in the cabin is controlled to a set value, and refrigerant is charged into the rear air conditioner according to the theoretical charge amount, while the front air conditioner piping is evacuated. Then, the vehicle is started and the dual air conditioning systems are activated, gradually charging the front air conditioner with refrigerant until the first preset charge amount is reached. Sensors collect pressure and temperature data at the heat exchanger outlet to calculate the optimal charge amount for the front air conditioner. After completing the front air conditioner test, the rear air conditioner piping is evacuated again, and the charging process is repeated to determine the optimal charge amount for the rear air conditioner. Throughout the process, the control unit dynamically adjusts the charging parameters through real-time data analysis and algorithm calculations to ensure the accuracy of the test results.

[0100] Through the above technical solution, the present invention can efficiently and accurately determine the refrigerant charge of a dual independent air conditioning system, avoiding the risk of decreased cooling efficiency or battery overheating due to improper charge. At the same time, the controllability and consistency of the test process are improved through automated control.

[0101] Taking the example of a processor and memory in a control device being connected via a bus, memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the control processor, and these remote memories can be connected to the controller via a network.

[0102] The non-transient software program and instructions required to implement the monitoring method of the above embodiments are stored in memory. When executed by a processor, the monitoring method in the above embodiments is executed, for example, the method described above is executed. Figure 2 Method steps S100 to S800 Figure 3 The method steps S410 to S430, etc.

[0103] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0104] Since the control device adopts all the technical solutions of the test method of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0105] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A test method for refrigerant charge quantity of a dual independent air conditioning system, applied to a hybrid bus with a dual independent air conditioning system, wherein the dual independent air conditioning system includes a front air conditioner and a rear air conditioner, characterized in that, The test method includes: Sensors were installed on the test vehicle and calibrated. The test vehicle was placed in an environmental chamber, and the temperature inside the environmental chamber was adjusted to reach the set temperature. Refrigerant is charged into the rear air conditioner according to the theoretical charge amount, and the refrigerant pipeline of the front air conditioner is evacuated. Start the test vehicle and turn on the front air conditioner and the rear air conditioner. Start charging the front air conditioner with refrigerant from the initial charge amount and gradually increase the charge amount until the first preset charge amount is reached. The optimal refrigerant charge for the front air conditioner is calculated based on the refrigerant charge range from the initial charge amount to the first preset charge amount. The refrigerant lines of the rear air conditioner were evacuated, and the test vehicle was restarted, with both the front and rear air conditioners turned on. The refrigerant is charged into the rear air conditioner starting from the initial charge amount, and the charge amount is gradually increased until the second preset charge amount is reached; The optimal refrigerant charge for the rear air conditioner is calculated based on the refrigerant charge range from the initial charge amount to the second preset charge amount.

2. The test method for refrigerant charge of a dual independent air conditioning system according to claim 1, characterized in that, The step of charging the refrigerant into the front air conditioner starting from an initial charge amount and gradually increasing the charge amount until a first preset charge amount is reached includes: The refrigerant is charged into the front air conditioner according to the initial charge amount, and then the refrigerant is added multiple times in succession with the charge amount increasing each time. The initial charge amount is the difference between the theoretical charge amount and the preset amount. When the refrigerant charge of the front air conditioner reaches the first preset charge amount, the control stops injecting refrigerant into the front air conditioner.

3. The test method for refrigerant charge of a dual independent air conditioning system according to claim 2, characterized in that, The step of controlling the cessation of refrigerant injection into the front air conditioner when the refrigerant charge of the front air conditioner reaches the first preset charge amount includes: Obtain the outlet pressure value of the indoor heat exchanger of the aforementioned air conditioner; When the outlet pressure of the indoor heat exchanger is greater than or equal to the first preset pressure value, the current refrigerant charge of the front air conditioner is determined to be the first preset charge, and the injection of refrigerant into the front air conditioner is stopped.

4. The test method for refrigerant charge of a dual independent air conditioning system according to claim 1, characterized in that, The step of charging the refrigerant into the rear air conditioner starting from an initial charge amount and gradually increasing the charge amount until a second preset charge amount is reached includes: The refrigerant is charged into the rear air conditioner according to the initial charge amount, and then the refrigerant is added multiple times in succession with the charge amount increasing each time. The initial charge amount is the difference between the theoretical charge amount and the preset amount. When the refrigerant charge of the rear air conditioner reaches the second preset charge amount, the control stops injecting refrigerant into the rear air conditioner.

5. The test method for refrigerant charge of a dual independent air conditioning system according to claim 4, characterized in that, When the refrigerant charge of the rear air conditioner reaches the second preset charge amount, controlling the stopping of refrigerant injection into the rear air conditioner includes: Obtain the outlet pressure value of the indoor heat exchanger of the rear air conditioner; When the outlet pressure of the indoor heat exchanger is greater than or equal to the second preset pressure value, the current refrigerant charge of the rear air conditioner is determined to be the second preset charge, and the injection of refrigerant into the rear air conditioner is stopped.

6. The test method for refrigerant charge of a dual independent air conditioning system according to claim 1, characterized in that, The step of charging the rear air conditioner with refrigerant according to the theoretical value of the charge amount includes: The theoretical value of the injection volume is calculated using the following formula: Q=(Vcomp +Vcond +Vevap +Vpipe) ρ ; Where Q represents the theoretical charge of refrigerant (in kg), Vcomp represents the internal volume of the compressor (in m³), ​​Vcond represents the internal volume of the condenser (in m³), ​​Vevap represents the internal volume of the evaporator (in m³), ​​Vpipe represents the internal volume of the refrigerant piping (in m³), ​​and ρ represents the saturated liquid density of the refrigerant at 40℃ (in kg / m³).

7. The test method for refrigerant charge of a dual independent air conditioning system according to claim 1, characterized in that, The step of calculating the optimal refrigerant charge for the front air conditioner based on the refrigerant charge range from the initial charge amount to the first preset charge amount includes: Based on the refrigerant charging process from the initial charge amount to the first preset charge amount, a first lower limit and a first upper limit of the refrigerant charge amount are determined; The optimal refrigerant charge of the front air conditioner is calculated based on the first lower limit, the first upper limit, and the optimal charge calculation formula. The step of calculating the optimal refrigerant charge for the rear air conditioner based on the refrigerant charge range from the initial charge amount to the second preset charge amount includes: Based on the refrigerant charging process from the initial charge amount to the second preset charge amount, a second lower limit value and a second upper limit value of the refrigerant charge amount are determined; The optimal refrigerant charge of the rear air conditioner is calculated based on the second lower limit, the second upper limit, and the optimal charge calculation formula. The formula for calculating the optimal refrigerant charge is: MO = ML + 0.75 × (MU - ML), where MO represents the optimal refrigerant charge; when calculating the optimal refrigerant charge of the front air conditioner, ML represents the first lower limit value; MU represents the first upper limit value; when calculating the optimal refrigerant charge of the rear air conditioner, ML represents the second lower limit value; MU represents the second upper limit value.

8. The test method for refrigerant charge of a dual independent air conditioning system according to claim 1, characterized in that, The sensors include a first sensor, a second sensor, a third sensor, a fourth sensor, and a fifth sensor. Installing the sensors on the test vehicle includes: The first sensor is installed at the front of the test vehicle, at the center height of the front of the test vehicle, to obtain the ambient temperature; The second sensor is installed at the air outlet of the test vehicle to obtain the air outlet temperature of the test vehicle. The third sensor is installed at the head of the passenger compartment of the test vehicle to obtain the temperature at the head of the passenger compartment. The fourth sensor is installed at the refrigerant outlet of the indoor heat exchanger of the front air conditioner and the rear air conditioner to obtain the outlet temperature of the indoor heat exchanger. The fifth sensor is installed at the refrigerant outlet of the indoor heat exchanger of the front air conditioner and the rear air conditioner to obtain the outlet pressure of the indoor heat exchanger.

9. A refrigerant charge system for a dual independent air conditioning system, applicable to the test method for the refrigerant charge of a dual independent air conditioning system as described in any one of claims 1 to 8, characterized in that, The refueling system includes: An environmental chamber for housing test vehicles, wherein the environmental chamber is configured to have an adjustable interior temperature to achieve a set temperature; The charging device is configured to charge the refrigerant into the rear air conditioner according to the theoretical charging amount and to perform vacuuming on the refrigerant pipeline of the front air conditioner. Start the test vehicle and turn on the front air conditioner and the rear air conditioner. Start charging the front air conditioner with refrigerant from the initial charge amount and gradually increase the charge amount until the first preset charge amount is reached. Calculate the optimal charge amount of refrigerant for the front air conditioner based on the charge range from the initial charge amount to the first preset charge amount. The refrigerant lines of the rear air conditioner are evacuated, and the test vehicle is restarted. The front and rear air conditioners are then turned on. Refrigerant is introduced into the rear air conditioner starting from the initial charge amount, and the charge amount is gradually increased until the second preset charge amount is reached. The optimal charge amount of refrigerant for the rear air conditioner is calculated based on the charge range from the initial charge amount to the second preset charge amount.

10. A control device, characterized in that, include: At least one processor; And a memory storing instructions that, when executed by at least one processor, perform the test method for refrigerant charge of a dual independent air conditioning system as described in any one of claims 1 to 8.

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