Vehicle air conditioning box, vehicle air conditioning system and control method of vehicle air conditioning system

Abstract

The invention provides a vehicle air conditioning box, a vehicle air conditioning system and a control method thereof.The vehicle air conditioning box comprises a box body shell, the box body shell is provided with an inner space, a main heat exchange air duct is formed in the inner space, and an air inlet and an air supply outlet are formed in the box body shell; an in-vehicle heat exchanger and an in-vehicle fan corresponding to the in-vehicle heat exchanger are arranged in the main heat exchange air duct, an inlet of the air return duct is controllably communicated with an air outlet side space of the in-vehicle heat exchanger, and an outlet of the air return duct is communicated with an air inlet side space of the in-vehicle heat exchanger. The air inlet side space and the air outlet side space are both located in the main heat exchange air duct. The air return duct is arranged on the air conditioning box, so that part of airflow subjected to heat exchange with the in-vehicle heat exchanger can be guided into the air inlet side space of the in-vehicle heat exchanger to enter the in-vehicle heat exchanger again for secondary heat exchange, and it is guaranteed that the air outlet temperature of the air conditioning system can reach the temperature value set by a user; and the use comfort and the satisfaction degree of the user are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioning, and in particular relates to a vehicle air conditioning box, a vehicle air conditioning system and a control method thereof. Background Art

[0002] When the new energy vehicle thermal management system uses R290 refrigerant, the indirect heat exchange method can reduce the amount of refrigerant, reduce possible leakage points, and prevent the refrigerant from entering the passenger compartment, thereby effectively solving the safety problem of R290 being flammable and explosive; but the indirect heat exchange system also brings new problems. In the air-conditioning cooling mode, the refrigerant circulates in the evaporator in the car for heat exchange. Compared with the direct cooling heat exchange of the refrigerant (refrigerant), the refrigerant heat exchange lacks the latent heat of phase change. This means that when the evaporator inlet temperature is the same, other conditions (return air temperature and humidity, evaporator volume, wind speed and air volume, etc.) are the same, the heat exchange capacity of the refrigerant is 15-32% lower than that of the refrigerant, and the outlet air temperature is 2-7°C higher. When the cooling demand is high, the air outlet of the indirect heat exchange system will give the user a poor experience. Therefore, how to solve the problem that the air outlet of the indirect heat exchange system will give the user a poor experience when the cooling demand is high is an urgent problem to be solved in this field. Summary of the invention

[0003] Therefore, the present invention provides a vehicle air-conditioning box, a vehicle air-conditioning system and a control method thereof, which can overcome the technical problems in the related art that the air-conditioning outlet temperature of the vehicle indirect heat exchange system is high when the cooling demand is high, resulting in poor user experience.

[0004] In order to solve the above problems, the present invention provides a vehicle air-conditioning box, including a box shell, the box shell having an internal space, a main heat exchange duct being formed in the internal space, the box shell being configured with an air inlet and an air supply outlet, an in-vehicle heat exchanger and a corresponding in-vehicle fan being arranged in the main heat exchange duct, the vehicle air-conditioning box also includes a return air duct, the inlet of the return air duct is controllably connected to the outlet side space of the in-vehicle heat exchanger, the outlet of the return air duct is connected to the inlet side space of the in-vehicle heat exchanger, and the inlet side space and the outlet side space are both in the main heat exchange duct.

[0005] In some embodiments, the return air duct is located in the internal space.

[0006] In some embodiments, a partition is provided in the internal space, and the partition divides the internal space into the main heat exchange air duct and the return air duct.

[0007] In some embodiments, the entrance of the return air duct is formed by the partition and the box shell; and / or a return air damper is provided in the entrance of the return air duct, and the return air damper has a connecting position for connecting the entrance of the return air duct with the air outlet side space and a truncation position for truncation.

[0008] In some embodiments, a water collecting structure is formed on the top surface of the partition, and the in-vehicle heat exchanger is disposed in an area above the partition and at a position corresponding to the water collecting structure.

[0009] In some embodiments, the in-vehicle fan is located between the in-vehicle heat exchanger and the inlet of the return air duct.

[0010] In some embodiments, the air inlet has an indoor return air area and an outdoor air inlet area, and an internal and external circulation air door is provided in the air inlet. The internal and external circulation air door has an internal circulation position that cuts off the outdoor air inlet area and connects to the indoor return air area, and an external circulation position that connects the outdoor air inlet area and cuts off the indoor return air area.

[0011] In some embodiments, a warm air heat exchanger is further provided in the main heat exchange air duct, and the in-vehicle fan is located between the in-vehicle heat exchanger and the warm air heat exchanger.

[0012] The present invention also provides a vehicle air-conditioning system, comprising the above-mentioned vehicle air-conditioning box, the vehicle air-conditioning system also comprising a refrigerant circulation system, the refrigerant circulation system comprising a plate heat exchanger, and the coolant in the vehicle heat exchanger and the refrigerant in the refrigerant circulation system realize indirect heat exchange in the plate heat exchanger.

[0013] In some embodiments, when the vehicle air conditioning box includes a warm air heat exchanger, an engine heat exchanger of the vehicle and the warm air heat exchanger form a brine circulation.

[0014] The present invention also provides a control method for the vehicle air conditioning system as described above, comprising the following steps:

[0015] Get the system operation mode signal;

[0016] When the system operation mode instruction is a cooling mode signal, the vehicle return air temperature tn and the air conditioning set temperature ts are obtained, and tn is compared with ts;

[0017] When tn≥ts, the inlet of the return air duct is controlled to be in communication with the air outlet side space, and the outlet of the return air duct is controlled to be in communication with the air inlet side space.

[0018] In some embodiments, when an internal and external circulation damper is set in the air inlet, when tn≥ts, the internal and external circulation damper is also controlled to be in the internal circulation position; and / or, when the system operates in a cooling mode, the supply air temperature tc at the supply air outlet is also obtained, and when tc≤ts-t1, the inlet of the return air duct is controlled to be cut off from the outlet side space, and t1 is the cooling temperature limit difference.

[0019] The vehicle air conditioning box, vehicle air conditioning system and control method thereof provided by the present invention have the following beneficial effects:

[0020] By setting a return air duct on the air conditioning box, a part of the airflow after heat exchange with the in-vehicle heat exchanger can be guided to the air inlet side space of the in-vehicle heat exchanger to enter the in-vehicle heat exchanger again for secondary heat exchange, so as to increase or decrease the temperature of the outlet airflow of the in-vehicle heat exchanger, ensure that the outlet air temperature of the air conditioning system can reach the user-set temperature value, and improve the user's comfort and satisfaction. It can be understood that in the present invention, by guiding part of the airflow after heat exchange with the heat exchanger to conduct secondary heat exchange with the heat exchanger, the heat exchange time between the airflow and the heat exchanger is objectively increased, and the heat exchange area is objectively increased without changing the size of the heat exchanger, thereby significantly improving the heat exchange efficiency of the heat exchanger, and more efficiently improving the temperature adjustment effect, especially for the in-vehicle heat exchanger of the present invention, which indirectly exchanges heat with the refrigerant circulation system through the refrigerant, to prevent the indirect heat exchange air conditioning system from having a relatively high outlet air temperature at the heat exchange end (that is, the in-vehicle heat exchanger) due to the lack of the phase change latent heat of the refrigerant system when the air conditioning system has a high load cooling demand. When the aforementioned in-car heat exchanger is used as an evaporator, the air outlet temperature can be lowered, thereby improving the user's cooling experience;

[0021] The return air duct is arranged in the internal space, which can improve the compactness of the structure of the vehicle air conditioning box, and does not occupy the space of the vehicle passenger compartment, the structural change is small, and the modification cost is low;

[0022] By arranging a partition in the aforementioned internal space, the internal space is divided into the aforementioned main heat exchange air duct and the return air duct, which has a simple structure and is easy to manufacture. The aforementioned partition is specifically assembled on the inner wall surface of the box shell to ensure that the two air ducts are relatively sealed and independent;

[0023] The inlet of the return air duct is formed by the partition plate and the box shell, so there is no need to process the inlet of the return air duct separately, which further simplifies the manufacturing process;

[0024] A water collection structure is arranged on the top surface of the partition and the in-vehicle heat exchanger is further arranged in the upper area of ​​the water collection structure, so that the condensed water generated during the operation of the in-vehicle heat exchanger can be collected and discharged to a target space, such as outside the vehicle or other condensed water utilization containers;

[0025] The in-vehicle fan is arranged at the upstream side of the inlet of the return air duct, so that the positive pressure formed by the in-vehicle fan in the aforementioned air outlet side space and the negative pressure formed in the aforementioned air inlet side space can be used to form the flow drive of the air flow in the return air duct, and there is no need to separately configure a corresponding return air fan in the return air duct, which simplifies the structural design and reduces the cost;

[0026] By arranging internal and external circulation dampers in the air inlet, selective blocking and conduction of the air inlet can be achieved, so that the air inlet can be used as an internal circulation air inlet and an external circulation air inlet. There is no need to separately configure corresponding dampers for the internal circulation air inlet and the external circulation air inlet of the vehicle air-conditioning system, which further simplifies the structural design and reduces the design and manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0028] Figure 1 Schematic diagram of the internal structure of a vehicle air conditioning box in an embodiment of the present invention, wherein arrows in the figure indicate the flow path of air flow;

[0029] Figure 2 is a schematic structural diagram of a vehicle air conditioning system in an embodiment of the present invention, wherein a refrigerant circulation system is partially schematically illustrated;

[0030] Figure 3 is a schematic diagram of the steps of a control method for a vehicle air conditioning system in an embodiment of the present invention;

[0031] Figure 4 Schematic diagram of the control logic of the vehicle air conditioning system in an embodiment of the present invention.

[0032] The accompanying drawings are marked as follows:

[0033] 1. Box shell; 11. Main heat exchange air duct; 12. Air inlet; 121. Internal and external circulation damper; 13. Air supply outlet; 14. In-vehicle heat exchanger; 15. In-vehicle fan; 16. Partition; 161. Water collection structure; 17. Warm air heat exchanger; 2. Return air duct; 21. Return air damper; 31. Return air temperature sensor; 32. Outlet air temperature sensor; 101. Plate heat exchanger; 102. First water pump; 103. Compressor; 104. Four-way valve; 105. External heat exchanger; 1051. External fan; 106. Electronic expansion valve; 107. Gas-liquid separator; 200. Engine heat exchanger; 201. Second water pump. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0036] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0037] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0038] See also Figure 1 and Figure 4 As shown, according to an embodiment of the present invention, a vehicle air conditioning box (i.e., HVAC) is provided, comprising a box shell 1, the box shell 1 having an internal space (not labeled in the figure), a main heat exchange air duct 11 is formed in the internal space, an air inlet 12 and an air supply port 13 are constructed on the box shell 1, an in-vehicle heat exchanger 14 and an in-vehicle fan 15 correspondingly configured therewith are arranged in the main heat exchange air duct 11, it can be understood that under the driving action of the aforementioned in-vehicle fan 15, the air flow will enter the main heat exchange air duct 11 from the air inlet 12 and exchange heat with the in-vehicle heat exchanger 14, and the air supply port 13 will be provided in the in-vehicle heat exchange air duct 11. The air is discharged from the outlet 13 to a temperature-controlled space (e.g., a passenger compartment of a vehicle). The vehicle air-conditioning box further comprises a return air duct 2, the inlet of the return air duct 2 being controllably connected to the outlet side space of the in-vehicle heat exchanger 14, the outlet of the return air duct 2 being connected to the inlet side space of the in-vehicle heat exchanger 14, and both the inlet side space and the outlet side space are located in the main heat exchange duct 11. In a specific embodiment, a coolant flows through the in-vehicle heat exchanger 14 to form indirect heat exchange with the refrigerant in a plate heat exchanger (e.g., the plate heat exchanger 101 described later) in the refrigerant circulation system.

[0039] In this technical solution, by arranging a return air duct 2 on the air-conditioning box, a part of the airflow after heat exchange with the in-vehicle heat exchanger 14 can be guided to the air inlet side space of the in-vehicle heat exchanger 14 and re-enter the in-vehicle heat exchanger 14 for secondary heat exchange, thereby increasing the temperature of the outlet airflow of the in-vehicle heat exchanger 14, ensuring that the outlet air temperature of the air-conditioning system can reach the temperature value set by the user, thereby improving the user's comfort and satisfaction. It can be understood that in the present invention, by guiding part of the airflow after heat exchange with the heat exchanger to perform secondary heat exchange with the heat exchanger, the heat exchange time between the airflow and the heat exchanger is objectively increased, and the heat exchange area is objectively increased without changing the size of the heat exchanger, thereby significantly improving the heat exchange efficiency of the heat exchanger, and more efficiently improving the temperature control effect, especially for the in-vehicle heat exchanger 14 of the present invention, which indirectly exchanges heat with the refrigerant circulation system through the refrigerant, to prevent the indirect heat exchange air conditioning system from having a relatively high air outlet temperature at the heat exchange end (that is, the in-vehicle heat exchanger 14) due to the lack of the phase change latent heat of the refrigerant system when the air conditioning system has a high load cooling demand, which brings a poor experience to the user. When the aforementioned in-vehicle heat exchanger 14 is used as an evaporator, the air outlet temperature can be reduced at this time, thereby improving the user's cooling experience.

[0040] In a feasible embodiment, the aforementioned return air duct 2 can be separately arranged outside the aforementioned box shell 1, and only form a controllable connection with the main heat exchange duct 11 in the aforementioned internal space through the inlet and outlet of the return air duct 2. However, since this structural design has the return air duct 2 on the outside of the box shell 1, the structural design is not compact enough, and the structural changes to the vehicle air-conditioning box are relatively large, and the modification cost is relatively high. As a preferred implementation method, the return air duct 2 is located in the internal space.

[0041] In this technical solution, the return air duct 2 is arranged in the internal space, which can improve the structural compactness of the vehicle air-conditioning box, and does not occupy the space of the vehicle passenger compartment. The structural change is small and the modification cost is low.

[0042] In a specific embodiment, see Figure 1 As shown, a partition 16 is provided in the internal space, and the partition 16 divides the internal space into the main heat exchange air duct 11 and the return air duct 2.

[0043] In this technical solution, a partition 16 is provided in the internal space so that the internal space is divided into the main heat exchange air duct 11 and the return air duct 2, which has a simple structure and is easy to manufacture. The partition 16 is specifically assembled on the inner wall surface of the box shell 1 to ensure that the two air ducts are relatively sealed and independent.

[0044] In some embodiments, the inlet of the return air duct 2 is formed by the partition plate 16 and the cabinet shell 1, so that there is no need to separately process the inlet of the return air duct 2, further simplifying the manufacturing process.

[0045] A return air damper 21 is provided in the entrance of the return air duct 2 to achieve controllable connection between the return air duct 2 and the air outlet side space, that is, the return air damper 21 has a connecting position for connecting the entrance of the return air duct 2 with the air outlet side space and a disconnecting position for disconnecting the entrance of the return air duct 2. The return air damper 21 is provided with a rotary motor (not shown in the figure), and the return air damper 21 is switched between the connecting position and the disconnecting position by controlling the rotary motor.

[0046] In some embodiments, a water collecting structure 161 is formed on the top surface of the partition 16, and the in-vehicle heat exchanger 14 is arranged in the upper area of ​​the partition 16 and its position corresponds to the water collecting structure 161. The aforementioned water collecting structure 161 is specifically a pit structure formed on the top surface of the partition 16. In another preferred embodiment, a drain pipe is provided at the low point of the pit structure.

[0047] In this technical solution, a water collecting structure 161 is arranged on the top surface of the partition 16 and the in-vehicle heat exchanger 14 is further arranged in the upper area of ​​the water collecting structure 161, so that the condensed water generated during the operation of the in-vehicle heat exchanger 14 can be collected and discharged to the target space, such as outside the vehicle or other condensed water utilization containers.

[0048] In a preferred embodiment, the in-vehicle fan 15 is located between the in-vehicle heat exchanger 14 and the inlet of the return air duct 2 , and the in-vehicle fan 15 may be a cross-flow fan.

[0049] In this technical solution, the in-vehicle fan 15 is arranged on the upstream side of the inlet of the return air duct 2, so that the positive pressure formed by the in-vehicle fan 15 in the aforementioned air outlet side space and the negative pressure formed in the aforementioned air inlet side space can be utilized to form a flow drive of air flow in the return air duct 2. There is no need to separately configure a corresponding return air fan in the return air duct 2, which simplifies the structural design and reduces costs.

[0050] In some embodiments, the air inlet 12 has an indoor return air area and an outdoor air inlet area, and an internal and external circulation damper 121 is provided in the air inlet 12. The internal and external circulation damper 121 has an internal circulation position that cuts off the outdoor air inlet area and connects to the indoor return air area, and an external circulation position that connects the outdoor air inlet area and cuts off the indoor return air area. That is, the air inlet 12 can be used as an external circulation air inlet or as an internal circulation air inlet, which further simplifies the design of the box shell 1.

[0051] In this technical solution, the air inlet 12 is selectively blocked and connected by setting an internal and external circulation damper 121 in the air inlet 12, so that the air inlet 12 can be used as an internal circulation air inlet and an external circulation air inlet. There is no need to separately configure corresponding dampers for the internal circulation air inlet and the external circulation air inlet of the vehicle air-conditioning system, which further simplifies the structural design and reduces the design and manufacturing costs.

[0052] The aforementioned internal and external circulation damper 121 is specifically configured with a rotary motor fixed to the box shell 1 to achieve position switching of the internal and external circulation damper 121, thereby ensuring reliable switching of the vehicle's internal and external circulation operating modes.

[0053] In some embodiments, a warm air heat exchanger 17 is also provided in the main heat exchange duct 11, and the in-vehicle fan 15 is located between the in-vehicle heat exchanger 14 and the warm air heat exchanger 17. At this time, in a preferred embodiment, the inlet of the return air duct 2 is set between the in-vehicle fan 15 and the warm air heat exchanger 17, so as to utilize the larger wind resistance of the warm air heat exchanger 17 to improve the reflux smoothness of the secondary heat exchange airflow.

[0054] In this technical solution, by arranging a warm air heat exchanger 17 in the main heat exchange air duct 11, when there is a heating demand in the passenger compartment, the warm air heat exchanger 17 can heat the outlet air flow to meet the user's heating demand.

[0055] A return air temperature sensor 31 is arranged on the inner side of the aforementioned air inlet 12 and in the indoor return air area to detect the temperature of the return air flow in real time. An outlet air temperature sensor 32 is arranged on the inner side of the air supply outlet 13 to detect the temperature of the outlet air flow (also known as the supply air flow) in real time. The aforementioned outlet air temperature sensor 32 is specifically arranged between the air supply outlet 13 and the warm air heat exchanger 17 to make the temperature detection of the outlet air flow more reliable and accurate.

[0056] According to an embodiment of the present invention, a vehicle air-conditioning system is also provided, comprising the above-mentioned vehicle air-conditioning box, the vehicle air-conditioning system also comprising a refrigerant circulation system (not labeled in the figure), the refrigerant circulation system comprising a plate heat exchanger 101, the coolant in the in-vehicle heat exchanger 14 and the refrigerant in the refrigerant circulation system realize indirect heat exchange in the plate heat exchanger 101, that is, the aforementioned plate heat exchanger 101 has a first heat exchange pipeline for circulating the coolant and a second heat exchange pipeline for circulating the refrigerant, so that heat exchange between the coolant and the refrigerant is realized in the same heat exchanger, that is, physical isolation of the refrigerant and the passenger compartment is achieved, effectively preventing the introduction of the refrigerant into the passenger compartment, which may cause refrigerant leakage, fire and other safety hazards.

[0057] See Figure 2As shown, the refrigerant circulation system is also equipped with a compressor 103, an off-vehicle heat exchanger 105, a four-way valve 104, an electronic expansion valve 106, and a gas-liquid separator 107. Each component is connected through a refrigerant pipeline to achieve the refrigerant circulation requirements of the refrigeration mode or heating mode of the refrigerant circulation system. For the refrigerant circulation where the in-vehicle heat exchanger 14 is located, a first water pump 102 is also configured to drive the refrigerant to circulate between the in-vehicle heat exchanger 14 and the plate heat exchanger 101 to ensure efficient heat exchange.

[0058] In another preferred embodiment, when the vehicle air conditioning box includes a warm air heat exchanger 17 (also called a warm air core), the vehicle's engine heat exchanger 200 and the warm air heat exchanger 17 form a coolant circulation. It should be noted that the coolant circulation and the circulation of the coolant in the aforementioned in-vehicle heat exchanger 14 are independent of each other.

[0059] In this technical solution, the warm air heat exchanger 17 can utilize the heat of the coolant in the engine heat exchanger 200 to heat the outlet air flow, which is more energy-saving and environmentally friendly.

[0060] According to an embodiment of the present invention, there is also provided a control method for the vehicle air conditioning system as described above, comprising the following steps:

[0061] Obtain system operation mode signal (also known as work instruction);

[0062] When the system operation mode instruction is a cooling mode signal, the return air temperature tn in the vehicle (specifically detected by the return air temperature sensor 31) and the air conditioning set temperature ts (specifically set by the user via the air conditioning operator (hand operator, central control screen, etc.)) are obtained, and the sizes of tn and ts are compared;

[0063] When tn≥ts, the inlet of the return air duct 2 is controlled to be connected with the air outlet side space, and the outlet of the return air duct 2 is controlled to be connected with the air inlet side space. It can be understood that at this time, the compressor 103 of the refrigerant circulation system is running, and the flow path switching of the four-way valve 104 is controlled so that the plate heat exchanger 101 can be used as an evaporator, so that the airflow entering the in-vehicle heat exchanger 14 can be cooled after heat exchange and part of it can enter the in-vehicle heat exchanger 14 again for secondary heat exchange, ensuring that the temperature of the outlet airflow is lower to meet the user's cooling demand; and when tn<ts, the return air duct 2 is kept cut off and no secondary heat exchange is performed.

[0064] In some embodiments, when an internal and external circulation damper 121 is provided in the air inlet 12, when tn≥ts, the internal and external circulation damper 121 is also controlled to be in the internal circulation position, that is, the air-conditioning system in the aforementioned cooling mode is in the internal circulation process, so that energy-saving and consumption-reducing operation can be achieved to meet a lower air outlet temperature.

[0065] During the system operation in the cooling mode, the supply air temperature tc at the supply air outlet 13 is also obtained (specifically detected by the aforementioned outlet air temperature sensor 32). When tc≤ts-t1, the inlet of the return air duct 2 is controlled to be cut off from the outlet side space to ensure the stability and durability of the cooling temperature. The aforementioned t1 is the cooling temperature limit difference, which generally ranges from 2-10°C. In a specific embodiment, it is 6°C. It can be specifically set by the user and can of course be preset in the control logic before leaving the factory.

[0066] Figure 4 Schematic diagram of the control logic of the vehicle air conditioning system in the embodiment of the present invention, which is specifically described as follows:

[0067] Step S110: the air conditioning control and adjustment unit receives a cooling mode signal and proceeds to step S210;

[0068] Step S210: Determine whether the return air temperature tn in the vehicle is greater than or equal to the air conditioning set temperature ts. If the return air temperature tn in the vehicle is greater than or equal to the air conditioning set temperature ts, proceed to step S220; if the return air temperature tn in the vehicle is less than the air conditioning set temperature ts, proceed to step S310;

[0069] Step S220: judging whether the internal and external circulation mode is the internal circulation according to the operation control unit signal, if the internal and external circulation mode is the internal circulation, proceeding to step S230; if the internal and external circulation mode is the external circulation, proceeding to step S221;

[0070] Step S221: The air conditioning control and adjustment unit sends a signal to the internal and external circulation mode damper, and the driving unit executes it, switches to the internal circulation, and enters step S230;

[0071] Step S230: The return air damper opening signal is sent by the air conditioning control and adjustment unit, and the drive unit executes it, and the return air damper is opened, and the process proceeds to step S240;

[0072] Step S240: Determine whether the outlet air temperature tc is less than or equal to the air conditioning set temperature ts cooling temperature limit difference t1. If the outlet air temperature tc is less than or equal to the air conditioning set temperature ts cooling temperature limit difference t1, proceed to step S250; if the outlet air temperature tc is greater than the air conditioning set temperature ts cooling temperature limit difference t1, return to step S240;

[0073] Step S250: The return air damper opening signal is sent by the air conditioning control and adjustment unit, and the drive unit executes it, and the return air damper is closed, and the process proceeds to step S310;

[0074] Step S310: End.

[0075] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A vehicle air conditioning box, comprising a box shell (1), the box shell (1) having an internal space, a main heat exchange air duct (11) formed in the internal space, an air inlet (12) and an air outlet (13) configured on the box shell (1), an in-vehicle heat exchanger (14) and an in-vehicle fan (15) correspondingly arranged therein are arranged in the main heat exchange air duct (11), characterized in that: It is characterized in that It also includes a return air duct (2), the inlet of the return air duct (2) being controllably connected to the air outlet side space of the in-vehicle heat exchanger (14), the outlet of the return air duct (2) being connected to the air inlet side space of the in-vehicle heat exchanger (14), and the air inlet side space and the air outlet side space are both located in the main heat exchange duct (11).

2. The vehicle air conditioning box according to claim 1, characterized in that: The return air duct (2) is located in the internal space.

3. The vehicle air conditioning box according to claim 2, characterized in that: A partition (16) is provided in the internal space, and the partition (16) divides the internal space into the main heat exchange air duct (11) and the return air duct (2).

4. The vehicle air conditioning box according to claim 3, characterized in that: The inlet of the return air duct (2) is formed by the partition plate (16) and the box shell (1); and / or a return air damper (21) is provided at the inlet of the return air duct (2), and the return air damper (21) has a connecting position for connecting the inlet of the return air duct (2) with the air outlet side space and a cutting-off position for cutting off the inlet of the return air duct (2).

5. The vehicle air conditioning box according to claim 3, characterized in that: A water collecting structure (161) is formed on the top surface of the partition (16), and the in-vehicle heat exchanger (14) is arranged in the upper area of ​​the partition (16) and its position corresponds to the water collecting structure (161).

6. The vehicle air conditioning box according to claim 3, characterized in that: The in-vehicle fan (15) is located between the in-vehicle heat exchanger (14) and the inlet of the return air duct (2).

7. The vehicle air conditioning box according to claim 1, characterized in that: The air inlet (12) has an indoor return air area and an outdoor air inlet area. An internal and external circulation damper (121) is provided in the air inlet (12). The internal and external circulation damper (121) has an internal circulation position that cuts off the outdoor air inlet area and connects to the indoor return air area, and an external circulation position that connects to the outdoor air inlet area and cuts off the indoor return air area.

8. The vehicle air conditioning box according to claim 1, characterized in that: A warm air heat exchanger (17) is also provided in the main heat exchange air duct (11), and the in-vehicle fan (15) is located between the in-vehicle heat exchanger (14) and the warm air heat exchanger (17).

9. A vehicle air conditioning system, characterized in that: The vehicle air conditioning box comprises any one of claims 1 to 8, and also comprises a refrigerant circulation system, wherein the refrigerant circulation system comprises a plate heat exchanger (101), and the coolant in the in-vehicle heat exchanger (14) and the refrigerant in the refrigerant circulation system realize indirect heat exchange in the plate heat exchanger (101).

10. The vehicle air conditioning system according to claim 9, characterized in that: When the vehicle air conditioning box includes a warm air heat exchanger (17), an engine heat exchanger (200) of the vehicle and the warm air heat exchanger (17) form a brine circulation.

11. A method for controlling a vehicle air conditioning system as claimed in claim 9, characterized in that: The steps include: Get the system operation mode signal; When the system operation mode instruction is a cooling mode signal, the return air temperature tn and the air conditioning set temperature ts in the vehicle are obtained, and the sizes of tn and ts are compared; When tn≥ts, the inlet of the return air duct (2) is controlled to be in communication with the air outlet side space, and the outlet of the return air duct (2) is controlled to be in communication with the air inlet side space.

12. The control method of the vehicle air conditioning system according to claim 11, characterized in that: When an internal and external circulation damper (121) is provided in the air inlet (12), when tn≥ts, the internal and external circulation damper (121) is also controlled to be in the internal circulation position; and / or, when the system is operating in a cooling mode, the supply air temperature tc at the supply air outlet (13) is also obtained, and when tc≤ts-t1, the inlet of the return air duct (2) is controlled to be cut off from the air outlet side space, and t1 is the cooling temperature limit difference.

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