Vehicle air conditioning system, control method, and vehicle

Abstract

This invention discloses a control method for a vehicle air conditioning system. Based on the deviation between the target and actual outlet air temperature of the front air conditioning assembly, the compressor speed is adjusted to change the condenser outlet subcooling, thus bringing the actual outlet air temperature of the front air conditioning assembly closer to the target outlet air temperature. Based on the deviation between the target and actual outlet air temperature of the rear air conditioning assembly, the opening of the electronic expansion valve is adjusted to change the refrigerant distribution ratio, thus bringing the actual outlet air temperature of the rear air conditioning assembly closer to the target outlet air temperature. This control method, by linking the outlet air temperature control of the front air conditioning assembly to the condenser subcooling and the outlet air temperature control of the rear air conditioning assembly to the opening of the electronic expansion valve, decouples the direct competition between the front and rear air conditioning systems for refrigerant distribution from a control logic perspective. This can improve the mutual disturbance of outlet air temperatures between the front and rear air conditioning systems and enhance the uniformity of refrigerant distribution in the evaporators of both systems. This invention also discloses a vehicle air conditioning system and a vehicle.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology for pure electric vehicles. Specifically, this invention relates to a vehicle air conditioning system, control method, and vehicle. Background Technology

[0002] Pure electric vehicles have large passenger cabins, so front and rear dual air conditioning systems have become the mainstream configuration in existing pure electric vehicles.

[0003] However, existing front and rear dual air conditioning systems generally use independent control logic for the front and rear, controlling the refrigerant flow to the corresponding evaporator by adjusting the opening of the front and rear electronic expansion valves to achieve independent adjustment of the outlet air temperature. But the front and rear evaporators share the compressor and condenser, and the adjustment of the two electronic expansion valves interferes with each other, resulting in uneven refrigerant distribution. This causes the outlet air temperature of the front and rear air conditioning systems to disturb each other, which not only affects passenger comfort but also reduces air conditioning energy efficiency and shortens the vehicle's range.

[0004] A control method for a vehicle air conditioning system is provided, particularly concerning the improvement of the mutual disturbance of the outlet air temperature between the front and rear air conditioning systems, the enhancement of the uniformity of refrigerant distribution in the evaporators of the front and rear air conditioning systems, and the improvement of passenger comfort. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a control method for a vehicle air conditioning system, the purpose of which is to improve the mutual disturbance of the outlet air temperature between the front and rear air conditioning systems, enhance the uniformity of refrigerant distribution in the evaporators of the front and rear air conditioning systems, and improve passenger comfort.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a control method for a vehicle air conditioning system, the vehicle air conditioning system including a compressor, a condenser, a front air conditioning assembly and a rear air conditioning assembly, the front air conditioning assembly including a front evaporator and a first electronic expansion valve, and the rear air conditioning assembly including a rear evaporator; the control method includes: Based on the first deviation between the target air outlet temperature and the actual air outlet temperature of the front air conditioning assembly, the target speed of the compressor is adjusted to change the outlet subcooling of the condenser, so that the actual air outlet temperature of the front air conditioning assembly approaches the target air outlet temperature. Based on the second deviation between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly, the opening of the first electronic expansion valve is adjusted to change the refrigerant distribution ratio in the system, so that the actual air outlet temperature of the rear air conditioning assembly approaches the target air outlet temperature.

[0007] Based on a first deviation between the target outlet air temperature and the actual outlet air temperature of the front air conditioning assembly, the target speed of the compressor is adjusted to change the outlet subcooling of the condenser, including: The target subcooling degree set for the condenser is calculated based on the first deviation. The actual subcooling degree at the condenser outlet is obtained, and the actual subcooling degree is determined based on the refrigerant temperature and condensing pressure at the condenser outlet. Based on the difference between the target subcooling and the actual subcooling, a target speed command for the compressor is output through a preset control algorithm, and the compressor is driven to run at the target speed.

[0008] When the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, the compressor speed is reduced to reduce the subcooling of the condenser outlet and increase the enthalpy difference of the refrigerant entering the front evaporator, thereby reducing the air outlet temperature of the front air conditioning assembly.

[0009] The preset control algorithm includes a proportional-integral-derivative control algorithm or a proportional-integral control algorithm.

[0010] Based on the second deviation between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly, the opening degree of the first electronic expansion valve controlling the refrigerant flow in the front air conditioning assembly is adjusted, including: Calculate the target opening command of the first electronic expansion valve based on the second deviation; The first electronic expansion valve is driven to adjust according to the target opening command; When the actual air outlet temperature of the rear air conditioner is higher than the target air outlet temperature, the opening of the first electronic expansion valve is reduced to increase the proportion of refrigerant flowing to the rear evaporator and improve the cooling capacity of the rear air conditioner assembly.

[0011] The step of changing the outlet subcooling of the condenser specifically includes: When the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, the target subcooling of the condenser is reduced, and the speed of the compressor is reduced accordingly, so as to increase the refrigerant enthalpy difference entering the front evaporator of the front air conditioning assembly.

[0012] The present invention also provides a vehicle air conditioning system, including a controller, a compressor, a condenser, a front air conditioning assembly, and a rear air conditioning assembly; The front air conditioning assembly includes a front evaporator and a first electronic expansion valve for controlling the refrigerant flow of the front air conditioning assembly, and the rear air conditioning assembly includes a rear evaporator; The controller is electrically connected to the compressor and the first electronic expansion valve, and the controller is configured to perform the control method.

[0013] The controller is configured to: calculate the target subcooling degree set for the condenser based on the first deviation between the target outlet air temperature and the actual outlet air temperature of the front air conditioning assembly, and adjust the target speed command of the compressor through a preset control algorithm based on the deviation between the target subcooling degree of the condenser and the actual subcooling degree determined based on the outlet temperature and the condensing pressure.

[0014] The controller is configured to calculate and output a target opening command for the first electronic expansion valve based on a second deviation between the target outlet air temperature and the actual outlet air temperature of the rear air conditioning assembly, so as to change the refrigerant flow rate entering the rear evaporator.

[0015] The vehicle air conditioning system also includes multiple temperature sensors, each electrically connected to the controller, and the multiple temperature sensors include: A front air outlet temperature sensor is used to detect the actual air outlet temperature of the front air conditioning assembly; The rear air outlet temperature sensor is used to detect the actual air outlet temperature of the rear air conditioning assembly; A condenser outlet temperature sensor is used to detect the refrigerant temperature at the condenser outlet.

[0016] The vehicle air conditioning system further includes a one-way valve and a third electronic expansion valve. The one-way valve is located on the refrigerant line between the outlet of the condenser and the inlet of the first electronic expansion valve, and the third electronic expansion valve is located on the refrigerant line between the inlet of the condenser and the outlet of the compressor.

[0017] When the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, the controller controls the compressor speed to be reduced, thereby reducing the subcooling of the condenser outlet.

[0018] The present invention also provides a vehicle including the aforementioned vehicle air conditioning system.

[0019] The vehicle air conditioning system control method of the present invention decouples the direct competition between the front and rear air conditioning assemblies for refrigerant distribution from the control logic by associating the air outlet temperature control of the front air conditioning assembly with the subcooling of the condenser and the air outlet temperature control of the rear air conditioning assembly with the opening of the first electronic expansion valve. This can improve the mutual disturbance of the air outlet temperature between the front and rear air conditioning systems, improve the uniformity of refrigerant distribution in the evaporators of the front and rear air conditioning systems, and improve passenger comfort. Attached Figure Description

[0020] Figure 1 This is a system schematic diagram of the front air conditioner of the present invention during operation; Figure 2 This is a system schematic diagram of the front and rear dual air conditioners of the present invention during operation; The markings in the above diagrams are as follows: 1. Compressor; 2. Third electronic expansion valve; 3. Condenser; 4. Check valve; 5. First electronic expansion valve; 6. Front evaporator; 7. Front compartment fan; 8. Second electronic expansion valve; 9. Rear evaporator; 10. Rear compartment fan. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," and similar expressions used in this document are for illustrative purposes only.

[0023] It should be noted that in the following embodiments, the terms "first," "second," and "third" do not represent an absolute distinction in structure and / or function, nor do they represent the order of execution; they are merely for the convenience of description.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] The technical concept of this invention includes: With the rapid development of new energy vehicle technology, pure electric vehicles have been widely used due to their advantages such as zero emissions and low energy consumption. Unlike traditional fuel vehicles, pure electric vehicles eliminate the internal combustion engine power system, and the entire vehicle's air conditioning system relies entirely on electric power, making it impossible to utilize engine waste heat for heating. Meanwhile, to meet consumers' growing demand for passenger comfort, especially in mid-to-large-sized pure electric SUVs and MPVs, where passenger cabin space is significantly increased, the cooling and heating needs of the rear passenger area are as important as those of the front. Therefore, more and more pure electric vehicles are beginning to be equipped with dual independent air conditioning systems, providing independent temperature control functions for the front and rear passenger cabins respectively. In the prior art, pure electric vehicles equipped with dual air conditioning systems generally adopt the logic of independent control of the front and rear air conditioning. Specifically, the front air conditioning circuit is equipped with a front electronic expansion valve. The vehicle air conditioning controller adjusts the opening of the front electronic expansion valve to change the refrigerant flow into the front evaporator, thereby controlling the front air conditioning outlet temperature. Correspondingly, the rear air conditioning circuit is equipped with a rear main electronic expansion valve. The opening of the rear main electronic expansion valve is adjusted to control the refrigerant flow into the rear evaporator, thereby achieving independent adjustment of the rear air conditioning outlet temperature.

[0026] However, the aforementioned traditional independent control method has significant drawbacks in practical applications. Since the front and rear evaporators share the same compressor and condenser system, the total refrigerant flow in the air conditioning system is limited by the compressor's operating status. When the front and rear air conditioners operate simultaneously and their refrigerant demands differ, the adjustment actions of the front electronic expansion valve and the rear main electronic expansion valve interfere with each other, failing to effectively balance the refrigerant distribution ratio between the front and rear circuits within the system. For example, when rear passengers increase their rear air conditioning cooling demand, the rear main electronic expansion valve opens more to increase the refrigerant flow to the rear evaporator, leading to insufficient refrigerant supply to the front evaporator. This causes the front air conditioning outlet temperature to rise, deviating from the front passengers' set value. Conversely, when the front air conditioning demand increases, it causes abnormal fluctuations in the rear air conditioning outlet temperature. This mutual disturbance of the front and rear air conditioning outlet temperatures not only severely affects the comfort experience of both front and rear passengers but also causes the air conditioning system to frequently adjust, increasing unnecessary energy consumption, reducing the overall energy efficiency of the air conditioning system, and consequently shortening the driving range of pure electric vehicles. The technical solution of this invention is as follows: Firstly, such as Figure 1 and Figure 2 As shown, this embodiment of the invention provides a vehicle air conditioning system, including a controller, a compressor 1, a condenser 3, a front air conditioning assembly, and a rear air conditioning assembly. The components are connected by refrigerant pipelines to form a refrigeration cycle loop. The compressor 1 is used to compress the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant, providing power for the entire refrigeration cycle.

[0027] The vehicle is divided into two passenger areas: a front cabin and a rear cabin. The front cabin is located in front of the rear cabin. The front cabin is equipped with a front air conditioning unit, and the rear cabin is equipped with a rear air conditioning unit.

[0028] The front air conditioning assembly includes a front evaporator 6 and a first electronic expansion valve 5 for controlling the refrigerant flow of the front air conditioning assembly; the rear air conditioning assembly includes a rear evaporator 9 and a second electronic expansion valve 8. The controller is electrically connected to the compressor 1 and the first electronic expansion valve 5, and the controller is configured to perform a control method for the vehicle air conditioning system.

[0029] Specifically, the vehicle air conditioning system and its control method provided in this embodiment of the invention aim to solve the problem of mutual disturbance of air outlet temperature caused by uneven refrigerant distribution between the front and rear evaporators 9 when the front and rear dual air conditioning systems are controlled independently in the prior art, thereby improving the control stability of the air conditioning system and passenger comfort, while optimizing system energy efficiency.

[0030] like Figure 1 and Figure 2 As shown, the front air conditioning assembly includes a front compartment fan 7 and a first electronic expansion valve 5. The first electronic expansion valve 5 is a motor-driven electronic expansion valve, and its opening degree can be adjusted by a pulse signal output by the controller, with an adjustment range of 0% to 100%. The inlet of the first electronic expansion valve 5 is connected to the outlet of the one-way valve 4, and the outlet of the first electronic expansion valve 5 is connected to the inlet of the front evaporator 6. The front evaporator 6 is used to evaporate and absorb heat from the throttled low-temperature, low-pressure gas-liquid two-phase refrigerant, cooling the air flowing through the front evaporator 6. The front compartment fan 7 is a blower, installed inside the front HVAC assembly (heating, ventilation, and air conditioning system) corresponding to the front evaporator 6, to drive the air inside the vehicle or fresh outside air to flow through the front evaporator 6, and to deliver the cooled air into the front compartment of the vehicle through the front compartment air outlet, thereby achieving cooling of the front compartment of the vehicle.

[0031] like Figure 1 and Figure 2 As shown, the rear air conditioning assembly includes a second electronic expansion valve 8 and a rear compartment fan 10. The second electronic expansion valve 8 is a motor-driven electronic expansion valve, and its opening degree can be adjusted by a pulse signal output by the controller, with an adjustment range of 0% to 100%. The inlet of the second electronic expansion valve 8 is connected to the outlet of the one-way valve 4, and the outlet of the second electronic expansion valve 8 is connected to the inlet of the rear evaporator 9. The structure of the rear evaporator 9 is the same as that of the front evaporator 6, and it is used to cool the air flowing through the rear evaporator 9. The rear compartment fan 10 is also a blower, installed inside the rear HVAC assembly (heating, ventilation and air conditioning system) corresponding to the rear evaporator 9, and is used to drive the air to flow through the rear evaporator 9, sending the cooled air into the rear compartment of the vehicle through the rear compartment air outlet to achieve cooling of the rear compartment of the vehicle.

[0032] like Figure 1 and Figure 2As shown, the outlets of the front evaporator 6 and the rear evaporator 9 are connected to the return port of the compressor 1 through refrigerant pipelines, thus forming a complete refrigeration cycle loop.

[0033] The vehicle air conditioning system of this embodiment of the invention also includes multiple temperature sensors, which are electrically connected to the controller to collect the operating parameters of the air conditioning system in real time. The multiple temperature sensors include: The front air outlet temperature sensor is used to detect the actual air outlet temperature of the front air conditioning assembly; The rear air outlet temperature sensor is used to detect the actual air outlet temperature of the rear air conditioning assembly; The condenser 3 outlet temperature sensor is used to detect the refrigerant temperature at the outlet of condenser 3.

[0034] Specifically, the front air outlet temperature sensor is located at the air outlet of the front air conditioning assembly to detect the actual air outlet temperature of the front air conditioning assembly in real time. The rear air outlet temperature sensor is located at the air outlet of the rear air conditioning assembly to detect the actual air outlet temperature of the rear air conditioning assembly in real time. The condenser 3 outlet temperature sensor is located on the outlet pipe of the condenser 3 to detect the refrigerant temperature at the outlet of the condenser 3 in real time.

[0035] like Figure 1 and Figure 2 As shown, the vehicle air conditioning system of this embodiment further includes a one-way valve 4 and a third electronic expansion valve 2. The one-way valve 4 is disposed on the refrigerant pipeline between the outlet of the condenser 3 and the inlet of the first electronic expansion valve 5, and the third electronic expansion valve 2 is disposed on the refrigerant pipeline between the inlet of the condenser 3 and the outlet of the compressor 1. The condenser 3 is disposed in the front-end heat dissipation module of the vehicle and is integrated with components such as the radiator. The condenser 3 is used to perform forced convection heat exchange between the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 and the outside air, so that the gaseous refrigerant is condensed into high-pressure liquid refrigerant. The inlet of the condenser 3 is connected to the outlet of the compressor 1 through a refrigerant pipeline, and the outlet of the condenser 3 is connected to the inlet of the one-way valve 4 through a refrigerant pipeline.

[0036] like Figure 1 and Figure 2 As shown, a one-way valve 4 is installed on the refrigerant line between the outlet of the condenser 3 and the inlets of the front and rear air conditioning assemblies to prevent refrigerant backflow and ensure the unidirectional nature of the refrigeration cycle. The outlet of the one-way valve 4 is divided into two paths via a tee connector: the first path connects to the inlet of the front air conditioning assembly, and the second path connects to the inlet of the rear air conditioning assembly, thus forming a refrigerant circuit architecture with the front and rear evaporators 9 connected in parallel. The third electronic expansion valve 2 is installed on the high-pressure refrigerant line between the outlet of the compressor 1 and the inlet of the condenser 3. In cooling mode, the third electronic expansion valve 2 remains in the fully open position and is used only as a refrigerant passage, without participating in the flow or temperature regulation of the refrigeration cycle.

[0037] When the actual air outlet temperature of the current air conditioning unit is higher than the target air outlet temperature, the controller controls the speed of compressor 1 to be reduced, thereby reducing the subcooling of the condenser 3 outlet.

[0038] In this embodiment of the invention, the controller is configured to: calculate the target subcooling degree set for the condenser 3 based on the first deviation between the target outlet air temperature and the actual outlet air temperature of the front air conditioning assembly, and adjust the target speed command of the compressor 1 through a preset control algorithm based on the deviation between the target subcooling degree of the condenser 3 and the actual subcooling degree determined based on the outlet temperature and condensing pressure.

[0039] In this embodiment of the invention, the controller is configured to: calculate and output a target opening command for the first electronic expansion valve 5 based on a second deviation between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly, so as to change the refrigerant flow rate entering the rear evaporator 9.

[0040] Figure 1 This diagram illustrates the system operation of the vehicle air conditioning system according to an embodiment of the present invention when only the front compartment requires cooling. Solid lines in the diagram represent pipelines where refrigerant actually flows under this condition, while dashed lines represent pipelines where no refrigerant flows. The connections of each component are as follows: The outlet of compressor 1 is connected sequentially to the inlet of the third electronic expansion valve 2 and the condenser 3 via refrigerant pipelines; the outlet of condenser 3 is connected to the inlet of one-way valve 4 via a refrigerant pipeline; the outlet of one-way valve 4 is connected to the inlet of the first electronic expansion valve 5 and the inlet of the second electronic expansion valve 8; the outlet of the first electronic expansion valve 5 is connected to the inlet of the front evaporator 6, and the outlet of the second electronic expansion valve 8 is connected to the inlet of the rear evaporator 9; the outlets of the front evaporator 6 and the rear evaporator 9 merge via refrigerant pipelines and are connected to the return port of compressor 1. The front compartment fan 7 is correspondingly positioned to the front evaporator 6, and the rear compartment fan 10 is correspondingly positioned to the rear evaporator 9.

[0041] Under this operating condition, the refrigerant flow is as follows: the high-temperature, high-pressure gaseous refrigerant discharged from compressor 1 enters condenser 3 through the third electronic expansion valve 2 (fully open), where it undergoes forced convection heat exchange with the outside air and is cooled into high-pressure subcooled liquid refrigerant; the high-pressure subcooled liquid refrigerant flows into the first electronic expansion valve 5 after passing through the one-way valve 4, and becomes low-temperature, low-pressure two-phase gas-liquid refrigerant after being throttled and depressurized by the first electronic expansion valve 5; the low-temperature, low-pressure refrigerant enters the front evaporator 6, absorbs heat from the air flowing through the front evaporator 6 and evaporates into gaseous refrigerant; the evaporated low-temperature, low-pressure gaseous refrigerant returns to compressor 1, completing a complete refrigeration cycle.

[0042] Figure 2 This diagram illustrates the system operation of a vehicle air conditioning system under the embodiment of the present invention when both the front and rear compartments require cooling. All pipes in the diagram are solid lines, indicating that refrigerant flows in both the front and rear air conditioning branches under this condition.

[0043] Under this operating condition, the refrigerant flow is as follows: the high-temperature, high-pressure gaseous refrigerant discharged from compressor 1 enters condenser 3 through the third electronic expansion valve 2, where it undergoes forced convection heat exchange with the outside air and is cooled into high-pressure subcooled liquid refrigerant. The high-pressure subcooled liquid refrigerant is then divided into two paths after passing through check valve 4. The first path flows into the first electronic expansion valve 5 and enters the front evaporator 6 to evaporate and absorb heat. The second path flows into the second electronic expansion valve 8 and enters the rear evaporator 9 to evaporate and absorb heat. The low-temperature, low-pressure gaseous refrigerant from the two paths merges in the low-pressure pipeline and returns to compressor 1, completing a complete refrigeration cycle.

[0044] At this time, both the front cabin fan 7 and the rear cabin fan 10 operate according to the air volume setting set by the user. When the cooling demand of the rear air conditioner suddenly increases, that is, when the rear air conditioner assembly requests to reduce the outlet air temperature, the outlet air temperature of the front air conditioner is controlled by adjusting the speed of the compressor 1 to change the subcooling of the condenser 3 outlet, and the outlet air temperature of the rear air conditioner is controlled by adjusting the opening of the first electronic expansion valve 5 to change the refrigerant distribution ratio of the front and rear branches.

[0045] Secondly, embodiments of the present invention provide a control method for a vehicle air conditioning system, comprising: Based on the first deviation ΔTf between the target air outlet temperature and the actual air outlet temperature of the front air conditioning assembly, the target speed of the compressor 1 is adjusted to change the subcooling of the condenser 3 outlet, so that the actual air outlet temperature of the front air conditioning assembly approaches the target air outlet temperature. Based on the second deviation ΔTr between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly, the opening of the first electronic expansion valve 5 controlling the refrigerant flow in the front air conditioning assembly is adjusted to change the refrigerant distribution ratio in the system, so that the actual air outlet temperature of the rear air conditioning assembly approaches the target air outlet temperature.

[0046] When only the front compartment of the vehicle requires cooling, and the rear compartment does not, the air conditioning system operates in a single front air conditioning mode. At this time, the rear compartment fan 10 of the rear air conditioning assembly stops operating, the second electronic expansion valve 8 remains closed, the rear compartment fan 10 does not operate, there is no airflow on the surface of the rear evaporator 9, heat exchange cannot occur, the refrigerant does not flow through the rear air conditioning branch, and all the refrigerant in the entire refrigeration cycle flows through the front air conditioning branch.

[0047] In the single-front air conditioning operating mode, the refrigerant flow is as follows: the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 enters the condenser 3 through the third electronic expansion valve 2, where it undergoes forced convection heat exchange with the outside air and is cooled into high-pressure subcooled liquid refrigerant; the high-pressure subcooled liquid refrigerant flows into the first electronic expansion valve 5 after passing through the one-way valve 4, and becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant after being throttled and depressurized by the first electronic expansion valve 5; the low-temperature and low-pressure refrigerant enters the front evaporator 6, where it absorbs heat from the air flowing through the front evaporator 6 and evaporates completely into gaseous refrigerant; the evaporated low-temperature and low-pressure gaseous refrigerant returns to the compressor 1 through the compressor 1 return port, completing a complete refrigeration cycle.

[0048] The control method for single-front air conditioning operation mode specifically includes the following steps: S101: The controller receives the target air outlet temperature Tf_set set by the user for the front air conditioning assembly.

[0049] S102: The front air outlet temperature sensor detects the actual air outlet temperature Tf_act of the front air conditioning assembly in real time and transmits the detected temperature signal to the controller.

[0050] S103: The controller calculates the first deviation ΔTf between the target air outlet temperature Tf_set and the actual air outlet temperature Tf_act of the air conditioning assembly, where ΔTf = Tf_set - Tf_act.

[0051] S104: The controller calculates the target subcooling degree SC_target of the condenser 3 using a first preset control algorithm (e.g., PI control algorithm) based on the first deviation ΔTf.

[0052] Specifically, when the first deviation ΔTf is positive, it means that the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, and the cooling capacity of the front air conditioning needs to be increased. At this time, the controller will output a lower target subcooling degree SC_target. When the first deviation ΔTf is negative, it means that the actual air outlet temperature of the front air conditioning assembly is lower than the target air outlet temperature, and the cooling capacity of the front air conditioning needs to be reduced. At this time, the controller will output a higher target subcooling degree SC_target.

[0053] S105: The controller obtains the actual subcooling degree SC_act at the outlet of condenser 3.

[0054] Specifically, the steps to obtain the actual supercooling degree SC_act include: S1051: The condenser 3 outlet temperature sensor detects the refrigerant temperature Tc_out at the outlet of condenser 3 in real time and transmits the detected temperature signal to the controller. S1052: A condensing pressure sensor installed at the outlet of condenser 3 detects the condensing pressure of condenser 3 in real time and transmits the detected pressure signal to the controller; S1053: The controller retrieves the saturation temperature Tsat corresponding to the condensing pressure by referring to the refrigerant saturation temperature-pressure mapping table pre-stored in the controller. S1054: The controller calculates the difference between the saturation temperature Tsat and the refrigerant temperature Tc_out at the outlet of condenser 3 to obtain the actual subcooling SC_act, i.e., SC_act = Tsat - Tc_out; S106: The controller calculates the deviation ΔSC between the target subcooling SC_target and the actual subcooling SC_act, where ΔSC = SC_target - SC_act; S107: The controller calculates the target speed N_comp_target of compressor 1 according to the deviation ΔSC using the second preset control algorithm, and outputs the target speed command to the compressor 1 driver via the CAN bus; The second preset control algorithm is a proportional-integral-derivative (PID) control algorithm, with the input being the deviation ΔSC and the output being the target speed of compressor 1, N_comp_target.

[0055] When the deviation ΔSC is negative, it means that the actual subcooling SC_act is higher than the target subcooling SC_target, and the subcooling of condenser 3 needs to be reduced. At this time, the controller will output a lower target speed of compressor 1 N_comp_target. When the deviation ΔSC is positive, it means that the actual subcooling SC_act is lower than the target subcooling SC_target, and the subcooling of condenser 3 needs to be increased. At this time, the controller will output a higher target speed of compressor 1 N_comp_target.

[0056] S108: The compressor 1 driver adjusts the actual speed of the compressor 1 according to the received target speed command, thereby changing the refrigerant flow and condensation effect through the condenser 3, so that the actual subcooling degree SC_act of the condenser 3 gradually approaches the target subcooling degree SC_target, and thus the actual air outlet temperature Tf_act of the front air conditioning assembly gradually approaches the target air outlet temperature Tf_set. The control method of this invention adopts a cross-control strategy to control the air outlet temperature of the front air conditioning assembly and the rear air conditioning assembly. The cross-control strategy includes: the air outlet temperature of the front air conditioning assembly is achieved by controlling the subcooling of the condenser 3, and the subcooling of the condenser 3 is adjusted by controlling the speed of the compressor 1; and the air outlet temperature of the rear air conditioning assembly is achieved by controlling the opening degree of the first electronic expansion valve 5 of the front air conditioning assembly.

[0057] The air outlet temperature of the front air conditioning assembly is achieved by controlling the subcooling of the condenser 3. Specifically, this includes adjusting the condenser 3 to set a target subcooling value based on the deviation between the target air outlet temperature and the actual air outlet temperature of the front air conditioning assembly, and adjusting the compressor 1 speed based on this target subcooling value.

[0058] The subcooling of condenser 3 is adjusted by controlling the speed of compressor 1. Specifically, based on the deviation between the actual subcooling at the outlet of condenser 3 and the target subcooling, the target speed command of compressor 1 is adjusted by PID (proportional-integral-derivative) or other control algorithms, and compressor 1 is driven to run at this target speed, thereby changing the subcooling of the refrigerant at the outlet of condenser 3 to the target value.

[0059] The outlet air temperature of the rear air conditioning assembly is controlled by adjusting the opening of the first electronic expansion valve 5 of the front air conditioning assembly. This includes: adjusting the target opening of the first electronic expansion valve 5 of the front air conditioning assembly based on the deviation between the target and actual outlet air temperature of the rear air conditioning assembly; influencing the refrigerant distribution within the system by changing the opening of the first electronic expansion valve 5; and adjusting the outlet air temperature of the rear air conditioning assembly to the target value. When the rear air conditioning assembly requests a reduction in outlet air temperature (i.e., the actual outlet air temperature of the rear air conditioning assembly is higher than the target outlet air temperature), the first electronic expansion valve 5 of the front air conditioning assembly is controlled to reduce its opening to increase the proportion of refrigerant flowing to the rear evaporator 9. When the front air conditioning assembly requests a reduction in outlet air temperature (i.e., the actual outlet air temperature of the front air conditioning assembly is higher than the target outlet air temperature), a lower subcooling is required at the refrigerant outlet of the condenser 3. This is achieved by reducing the speed of the compressor 1 to achieve a lower subcooling, thereby increasing the enthalpy difference of the refrigerant entering the front evaporator 6 and reducing the outlet air temperature of the front air conditioning assembly.

[0060] In this embodiment of the invention, adjusting the target speed of compressor 1 to change the outlet subcooling of condenser 3 based on the first deviation ΔTf between the target outlet air temperature and the actual outlet air temperature of the front air conditioning assembly includes: The target subcooling degree set for condenser 3 is calculated based on the first deviation ΔTf. Obtain the actual subcooling at the outlet of condenser 3. The actual subcooling is determined based on the refrigerant temperature and condensing pressure at the outlet of condenser 3. Based on the difference between the target subcooling and the actual subcooling, the target speed command of compressor 1 is output through a preset control algorithm, and compressor 1 is driven to run at the target speed.

[0061] In this embodiment of the invention, when the actual air outlet temperature of the current air conditioning assembly is higher than the target air outlet temperature, the speed of the compressor 1 is reduced to reduce the subcooling of the condenser 3 outlet and increase the enthalpy difference of the refrigerant entering the front evaporator 6, thereby reducing the air outlet temperature of the front air conditioning assembly.

[0062] In this embodiment of the invention, adjusting the opening of the first electronic expansion valve 5 controlling the refrigerant flow in the front air conditioning assembly based on the second deviation ΔTr between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly includes: The target opening command for the first electronic expansion valve 5 is calculated based on the second deviation. The first electronic expansion valve 5 is driven to adjust according to the target opening degree command; When the actual air outlet temperature of the rear air conditioner is higher than the target air outlet temperature, the first electronic expansion valve 5 is controlled to reduce its opening, increasing the proportion of refrigerant flowing to the rear evaporator 9 and improving the cooling capacity of the rear air conditioner assembly.

[0063] In this embodiment of the invention, the step of changing the outlet subcooling of the condenser 3 specifically includes: When the actual air outlet temperature of the current air conditioning assembly is higher than the target air outlet temperature, the target subcooling of the condenser 3 is reduced, and the speed of the compressor 1 is reduced accordingly, so as to increase the refrigerant enthalpy difference entering the front evaporator 6 of the front air conditioning assembly.

[0064] Furthermore, the following is combined with Figure 2 The control method of the vehicle air conditioning system in the simultaneous operation mode of the front and rear air conditioners according to the embodiments of the present invention will be described in detail.

[0065] When both the front and rear compartments of the vehicle require cooling, the air conditioning system operates in a dual-air conditioning mode. At this time, both the front compartment fan 7 and the rear compartment fan 10 operate according to the airflow setting set by the user, and the refrigerant flows through both the front and rear air conditioning circuits simultaneously, providing cooling for the front and rear compartments respectively.

[0066] The control logic of the front air conditioning outlet temperature control loop is basically the same as that of the single front air conditioning working mode. By adjusting the speed of compressor 1, the subcooling of condenser 3 outlet is changed, thereby changing the cooling capacity of front evaporator 6, so as to control the front air conditioning outlet temperature and make the actual outlet temperature of the front air conditioning assembly approach the target outlet temperature.

[0067] When both front and rear air conditioners are operating simultaneously, the temperature control of the rear air conditioner's outlet air includes the following steps: S201: The controller receives the target air outlet temperature Tr_set set by the user for the rear air conditioning assembly.

[0068] S202: The rear air outlet temperature sensor detects the actual air outlet temperature Tr_act of the rear air conditioning assembly in real time and transmits the detected temperature signal to the controller.

[0069] S203: The second deviation ΔTr between the target air outlet temperature Tr_set and the actual air outlet temperature Tr_act after the controller calculation, where ΔTr = Tr_set - Tr_act.

[0070] S204: The controller calculates the target opening degree Opening_f_target of the first electronic expansion valve 5 based on the second deviation ΔTr using the third preset control algorithm.

[0071] The third preset control algorithm is also a PI control algorithm, with the second deviation ΔTr as input and the target opening degree of the first electronic expansion valve 5 as output. In this embodiment of the invention, in order to ensure that the front air conditioning branch always has a certain refrigerant flow and to prevent the front air conditioning from completely losing its cooling capacity, the minimum opening degree of the first electronic expansion valve 5 is limited to 15%, and the maximum opening degree is 100%. This minimum opening value can be adjusted according to the characteristics of the air conditioning system of different vehicle models.

[0072] For example, when the rear air conditioning assembly requires a lower temperature, and the absolute value of ΔTr is positive and large, the controller will issue a command to reduce the opening of the first electronic expansion valve 5 (reduction valve).

[0073] The actuator of the first electronic expansion valve 5 adjusts its opening according to the calculated target opening degree Opening_f_target. When the opening degree of the first electronic expansion valve 5 decreases, its throttling effect is enhanced, which will cause more refrigerant to flow to the relatively low-pressure rear evaporator 9, thereby increasing the refrigerant flow to the rear evaporator 9, increasing the cooling capacity of the rear air conditioning assembly, and reducing the actual outlet air temperature Tr_act.

[0074] S205: The controller outputs a target opening pulse command to the motor of the first electronic expansion valve 5, driving the first electronic expansion valve 5 to adjust according to the target opening Opening_f_target.

[0075] S206: By adjusting the opening of the first electronic expansion valve 5, the proportion of refrigerant flowing to the rear evaporator 9 is indirectly controlled, so that the actual air outlet temperature Tr_act of the rear air conditioning assembly approaches the target air outlet temperature Tr_set.

[0076] In the aforementioned control logic, the control of the front air conditioning assembly is primarily achieved through the compressor speed 1 and the subcooling degree of the condenser 3. This loop is relatively independent and not directly affected by the control of the second electronic expansion valve 8. The control of the rear air conditioning assembly is achieved through the adjustment of the opening degree of the first electronic expansion valve 5, utilizing the coupling characteristics of the system's refrigerant distribution to achieve indirect but effective control of the rear air conditioning assembly. This cross-control strategy breaks the traditional direct and independent control mode, fundamentally avoiding the direct conflict in refrigerant distribution caused by the adjustment of the second electronic expansion valve 8, thereby effectively solving the problem of mutual disturbance between the front and rear air outlet temperatures.

[0077] For example, when the rear air conditioning unit requests a low outlet temperature, the system instructs the first electronic expansion valve 5 to close, increasing the refrigerant supply to the rear evaporator 9. At this time, the cooling demand of the front air conditioning unit is met by adjusting the subcooling of the condenser 3 (i.e., the compressor 1 speed), and the impact of the adjustment of the first electronic expansion valve 5 on its own outlet temperature is compensated by the adjustment of the compressor 1 speed. Similarly, when the front air conditioning unit requests a low outlet temperature, the system reduces the subcooling of the condenser 3 (by reducing the compressor 1 speed). If this affects the temperature of the rear air conditioning unit, the temperature of the rear air conditioning unit can be corrected by further fine-tuning the opening of the first electronic expansion valve 5.

[0078] When the second deviation ΔTr is positive, it indicates that the actual outlet air temperature of the rear air conditioning unit is higher than the target outlet air temperature, requiring an increase in the cooling capacity of the rear air conditioning system. At this time, the controller will output a command to reduce the opening of the first electronic expansion valve 5. As the opening of the first electronic expansion valve 5 decreases, the flow resistance in the front air conditioning branch increases. The refrigerant flow in the rear air conditioning branch will increase, while the refrigerant flow in the front air conditioning branch will decrease. The refrigerant flow in the rear evaporator 9 increases, increasing its total cooling capacity, thereby lowering the outlet air temperature of the rear air conditioning system.

[0079] When the second deviation ΔTr is negative, it indicates that the actual outlet air temperature of the rear air conditioning unit is lower than the target outlet air temperature, requiring a reduction in the cooling capacity of the rear air conditioning system. At this time, the controller will output a command to increase the opening of the first electronic expansion valve 5. As the opening of the first electronic expansion valve 5 increases, the flow resistance in the front air conditioning branch decreases. The refrigerant flow in the rear air conditioning branch will decrease, reducing the total cooling capacity of the rear evaporator 9, thereby increasing the outlet air temperature of the rear air conditioning system.

[0080] Furthermore, when the opening of the first electronic expansion valve 5 changes, causing a change in the refrigerant flow rate of the front air conditioning branch, the front air conditioning outlet temperature control loop will detect the change in the front air conditioning outlet temperature and compensate for the impact of the refrigerant flow rate change on the cooling capacity of the front air conditioning by adjusting the speed of the compressor 1 and changing the subcooling of the condenser 3.

[0081] The cross-control strategy proposed in this invention decouples the direct competition between the front and rear air conditioning assemblies for refrigerant distribution by associating the outlet air temperature control of the front air conditioning assembly with the subcooling degree of the condenser 3 (compressor 1 speed) and the outlet air temperature control of the rear air conditioning assembly with the opening degree of the first electronic expansion valve 5. This innovation enables: 1. Fundamentally Solving the Mutual Disturbance Problem: This invention employs an innovative cross-control strategy, linking the outlet air temperature control of the front air conditioning assembly to the subcooling of the condenser 3 (via the compressor 1 speed), thus freeing it from direct influence by the second electronic expansion valve 8. The outlet air temperature control of the rear air conditioning assembly is then linked to the first electronic expansion valve 5, forming a new closed-loop control logic. This design makes the temperature control links of the front and rear air conditioning assemblies relatively independent, avoiding temperature fluctuations caused by direct mutual interference in refrigerant distribution during traditional independent control. This fundamentally solves the problem of mutual disturbance between the front and rear outlet air temperatures, improving the stability and control accuracy of the air conditioning system.

[0082] 2. Enhanced comfort: Eliminating the mutual disturbance between the front and rear air vent temperatures allows the temperature in the front and rear passenger areas to reach and maintain the set target value more quickly and stably, significantly improving the comfort experience for passengers.

[0083] 3. Optimize system energy efficiency potential: By precisely controlling the subcooling of condenser 3 and the speed of compressor 1, the efficiency of the entire refrigeration cycle can be optimized. Combined with reasonable refrigerant distribution, this helps to improve the overall energy efficiency ratio of the air conditioning system and reduce energy consumption.

[0084] Thirdly, embodiments of the present invention also provide a vehicle including a vehicle air conditioning system with the above-described structure. The vehicle is a new energy vehicle, and this vehicle air conditioning system can be referred to... Figures 1 to 2 Further details will not be elaborated here. Since the vehicle of the present invention includes the vehicle air conditioning system described in the above embodiments, it possesses all the advantages of the aforementioned vehicle air conditioning system.

[0085] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A control method for a vehicle air conditioning system, the vehicle air conditioning system comprising a compressor, a condenser, a front air conditioning assembly, and a rear air conditioning assembly, the front air conditioning assembly comprising a front evaporator and a first electronic expansion valve, and the rear air conditioning assembly comprising a rear evaporator; characterized in that, The control method includes: Based on the first deviation between the target air outlet temperature and the actual air outlet temperature of the front air conditioning assembly, the target speed of the compressor is adjusted to change the outlet subcooling of the condenser, so that the actual air outlet temperature of the front air conditioning assembly approaches the target air outlet temperature. Based on the second deviation between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly, the opening of the first electronic expansion valve is adjusted to change the refrigerant distribution ratio in the system, so that the actual air outlet temperature of the rear air conditioning assembly approaches the target air outlet temperature.

2. The control method according to claim 1, characterized in that, Based on a first deviation between the target outlet air temperature and the actual outlet air temperature of the front air conditioning assembly, the target speed of the compressor is adjusted to change the outlet subcooling of the condenser, including: The target subcooling degree set for the condenser is calculated based on the first deviation. The actual subcooling degree at the condenser outlet is obtained, and the actual subcooling degree is determined based on the refrigerant temperature and condensing pressure at the condenser outlet. Based on the difference between the target subcooling and the actual subcooling, a target speed command for the compressor is output through a preset control algorithm, and the compressor is driven to run at the target speed.

3. The control method according to claim 2, characterized in that, When the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, the compressor speed is reduced to reduce the subcooling of the condenser outlet and increase the enthalpy difference of the refrigerant entering the front evaporator, thereby reducing the air outlet temperature of the front air conditioning assembly.

4. The control method for a vehicle air conditioning system according to claim 3, characterized in that, The preset control algorithm includes a proportional-integral-derivative control algorithm or a proportional-integral control algorithm.

5. The control method according to claim 1, characterized in that, Based on the second deviation between the target air outlet temperature and the actual air outlet temperature of the rear air conditioning assembly, the opening degree of the first electronic expansion valve controlling the refrigerant flow in the front air conditioning assembly is adjusted, including: Calculate the target opening command of the first electronic expansion valve based on the second deviation; The first electronic expansion valve is driven to adjust according to the target opening command; When the actual air outlet temperature of the rear air conditioner is higher than the target air outlet temperature, the opening of the first electronic expansion valve is reduced to increase the proportion of refrigerant flowing to the rear evaporator and improve the cooling capacity of the rear air conditioner assembly.

6. The control method according to claim 1, characterized in that, The step of changing the outlet subcooling of the condenser specifically includes: When the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, the target subcooling of the condenser is reduced, and the speed of the compressor is reduced accordingly, so as to increase the refrigerant enthalpy difference entering the front evaporator of the front air conditioning assembly.

7. A vehicle air conditioning system, characterized in that, This includes the controller, compressor, condenser, front air conditioning assembly, and rear air conditioning assembly; The front air conditioning assembly includes a front evaporator and a first electronic expansion valve for controlling the refrigerant flow of the front air conditioning assembly, and the rear air conditioning assembly includes a rear evaporator; The controller is electrically connected to the compressor and the first electronic expansion valve, and the controller is configured to perform the control method as described in any one of claims 1 to 6.

8. The vehicle air conditioning system according to claim 7, characterized in that, The controller is configured to: calculate the target subcooling degree set for the condenser based on the first deviation between the target outlet air temperature and the actual outlet air temperature of the front air conditioning assembly, and adjust the target speed command of the compressor through a preset control algorithm based on the deviation between the target subcooling degree of the condenser and the actual subcooling degree determined based on the outlet temperature and the condensing pressure.

9. The vehicle air conditioning system according to claim 7, characterized in that, The controller is configured to calculate and output a target opening command for the first electronic expansion valve based on a second deviation between the target outlet air temperature and the actual outlet air temperature of the rear air conditioning assembly, so as to change the refrigerant flow rate entering the rear evaporator.

10. The vehicle air conditioning system according to claim 7, characterized in that, It also includes multiple temperature sensors, each electrically connected to the controller, and the multiple temperature sensors include: A front air outlet temperature sensor is used to detect the actual air outlet temperature of the front air conditioning assembly; The rear air outlet temperature sensor is used to detect the actual air outlet temperature of the rear air conditioning assembly; A condenser outlet temperature sensor is used to detect the refrigerant temperature at the condenser outlet.

11. The vehicle air conditioning system according to claim 6, characterized in that, It also includes a one-way valve and a third electronic expansion valve. The one-way valve is located on the refrigerant line between the outlet of the condenser and the inlet of the first electronic expansion valve, and the third electronic expansion valve is located on the refrigerant line between the inlet of the condenser and the outlet of the compressor.

12. The vehicle air conditioning system according to claim 6, characterized in that, When the actual air outlet temperature of the front air conditioning assembly is higher than the target air outlet temperature, the controller controls the compressor speed to be reduced, thereby reducing the subcooling of the condenser outlet.

13. A vehicle, characterized in that, Includes the vehicle air conditioning system as described in any one of claims 7 to 12.

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