HVAC system of vehicle and control method thereof

Abstract

The invention relates to an HVAC system of a vehicle and a control method thereof. A heating, ventilation, and air conditioning (HVAC) system of a vehicle includes a compressor, an internal condenser located on a downstream side of the compressor and disposed in an HVAC housing, a heating side expansion valve located on a downstream side of the internal condenser, a water-cooled heat exchanger located on a downstream side of the heating side expansion valve, and a controller. The controller is configured to adjust an opening degree of the heating-side expansion valve based on a temperature difference between air flowing from the internal condenser to a front seat of a cabin of the vehicle and air flowing from the internal condenser to a rear seat of the cabin. The controller is further configured to adjust the opening degree based on heat (heat release amount) transferred from the internal condenser to the air.

Description

[0001] Cross - reference to related applications

[0002] This application is based on and claims priority and benefit from Korean Patent Application No. 10 - 2023 - 0178071, filed with the Korean Intellectual Property Office on December 8, 2023, the entire content of which is incorporated herein by reference. Technical field

[0003] The present invention relates to a heating, ventilation, and air - conditioning (HVAC) system for a vehicle and a control method thereof. More specifically, the present invention relates to an HVAC system for a vehicle and a control method thereof, which are designed to adjust the opening degree of a heating - side expansion valve. Background art

[0004] With the increasing concerns about energy efficiency and environmental issues, there is a need to develop eco - friendly vehicles that can replace internal combustion engine vehicles. Such eco - friendly vehicles are classified into electric vehicles that use fuel cells or electricity as a power source for driving and hybrid vehicles that use an engine and a battery for driving.

[0005] An electric vehicle or a hybrid vehicle may include a vehicle thermal management system for heating, ventilation, and air - conditioning (HVAC) in a passenger compartment (or cabin). In addition, the vehicle thermal management system can keep the battery and / or power electronics (PE) components at an appropriate temperature. The vehicle thermal management system may include: an HVAC system for HVAC in the passenger compartment, a PE cooling system for keeping the PE components at an appropriate temperature, and a battery cooling system for keeping the battery at an appropriate temperature.

[0006] To operate in the heating mode, the HVAC system may include a compressor, an internal condenser arranged downstream of the compressor, a heating - side expansion valve arranged downstream of the internal condenser, and a water - cooled heat exchanger arranged downstream of the heating - side expansion valve. The internal condenser may be arranged in the HVAC housing. When the refrigerant flows through the internal passage of the internal condenser and air passes over the outer surface of the internal condenser, the air can be heated by the internal condenser.

[0007] To avoid operation limitations caused by a pressure drop of the refrigerant, the internal condenser disposed in the HVAC housing may be configured such that the refrigerant can flow in one direction. Accordingly, the temperature of the air passing over the outer surface of the internal condenser may vary depending on the portion of the outer surface of the internal condenser. For example, the internal condenser may have an inlet header located above an outlet header and may have a plurality of tubes connecting the inlet header and the outlet header. As the refrigerant flows from the inlet header to the outlet header through the plurality of tubes, the refrigerant may exchange heat with the air. In addition, a temperature difference may occur between the air passing over the upper portion of the internal condenser and the air passing over the lower portion of the internal condenser. The air passing over the upper portion of the internal condenser may be directed toward the front seats of the vehicle through an outlet of the HVAC housing. The air passing over the lower portion of the internal condenser may be directed toward the rear seats of the passenger compartment through a rear seat duct. Accordingly, a temperature difference may occur between the temperature of the air directed toward the front seats of the passenger compartment and the temperature of the air directed toward the rear seats of the passenger compartment. Hereinafter, the term "temperature difference" is used to denote the temperature difference between the temperature of the air flowing from the internal condenser to the front seats of the passenger compartment and the temperature of the air flowing from the internal condenser to the rear seats of the passenger compartment.

[0008] In a state where the HVAC system is operating in a heating mode, when the opening degree of the heating-side expansion valve increases, the flow resistance of the refrigerant may relatively decrease. Since the difference between the suction pressure (suction temperature) of the compressor and the discharge pressure (discharge temperature) of the compressor relatively decreases, the temperature and pressure of the refrigerant flowing into the internal condenser decrease, and the flow rate of the refrigerant flowing into the internal condenser increases. As the opening degree of the heating-side expansion valve increases, the amount of heat transferred from the internal condenser to the air (heat release amount) relatively decreases. In addition, as the flow rate of the refrigerant flowing into the internal condenser increases, the difference between the temperature of the refrigerant flowing into the inlet header and the temperature of the refrigerant discharged from the outlet header decreases. Accordingly, the temperature difference may be relatively reduced.

[0009] As the opening degree of the heating-side expansion valve increases, the heat release amount can be relatively reduced. Accordingly, the cabin heating performance of the HVAC system may decrease. As the opening degree of the heating-side expansion valve decreases, the heat release amount can be relatively increased. Accordingly, the cabin heating performance of the HVAC system can be improved. In other words, the heat release amount and the cabin heating performance of the HVAC system can be inversely proportional to the opening degree of the heating-side expansion valve. In addition, as the opening degree of the heating-side expansion valve increases, the temperature of the air guided to the rear seats in the cabin will relatively increase, resulting in a decrease in the temperature difference. As the opening degree of the heating-side expansion valve decreases, the temperature of the air guided to the rear seats in the cabin will relatively decrease, resulting in an increase in the temperature difference. In other words, the temperature of the air guided to the rear seats in the cabin can be directly proportional to the opening degree of the heating-side expansion valve, and the temperature difference can be inversely proportional to the opening degree of the heating-side expansion valve. According to the opening degree of the heating-side expansion valve, the cabin heating performance and the temperature difference may conflict with each other. Therefore, under heating conditions, in order to reduce the temperature difference, cabin heating may not be effectively carried out.

[0010] The above information described in this background art section is provided to assist in understanding the background of the inventive concept. Therefore, the information described in the background art section may include any technical concepts known to those of ordinary skill in the art that are not considered prior art. Summary of the Invention

[0011] The present invention is dedicated to solving the above problems arising in the prior art while fully maintaining the advantages achieved by the prior art.

[0012] One aspect of the present invention provides a heating, ventilation, and air conditioning (HVAC) system for a vehicle and a control method thereof. The HVAC system is configured to adjust the opening degree of the heating-side expansion valve according to a uniform discharge temperature mode and a heating enhancement mode when the HVAC system is operating in a heating mode. As a result, the system appropriately addresses the conflict between the cabin heating performance and the temperature difference.

[0013] According to one aspect of the present invention, there is provided a vehicle HVAC system. The system may include: a compressor, an internal condenser, a heating-side expansion valve, a water-cooled heat exchanger, and a controller; the internal condenser is located downstream of the compressor and is arranged in the HVAC housing; the heating-side expansion valve is located downstream of the internal condenser; the water-cooled heat exchanger is located downstream of the heating-side expansion valve. The controller is configured to: adjust the opening degree of the heating-side expansion valve based on the temperature difference between the air flowing from the internal condenser to the front seats in the vehicle cabin and the air flowing from the internal condenser to the rear seats in the cabin. In addition, the controller is configured to adjust the opening degree of the heating-side expansion valve based on the heat (heat release amount) transferred from the internal condenser to the air.

[0014] The controller can be configured to determine a first opening degree of the heating-side expansion valve according to a uniform discharge temperature mode based on the temperature difference, or can be configured to determine a second opening degree of the heating-side expansion valve according to a heating enhancement mode based on the heat release amount.

[0015] The controller can be configured to determine a minimum opening degree of the heating-side expansion valve based on the revolutions per minute (RPM) of the compressor and the outside air temperature. The controller can be configured to determine a target opening degree of the heating-side expansion valve based on the RPM of the compressor, the outside air temperature, and the discharge pressure of the compressor.

[0016] The controller can be configured to determine an acceptable temperature difference based on the temperature drop rate of the air flowing from the internal condenser to the rear seats in the vehicle compartment.

[0017] The controller can be configured to calculate the temperature drop rate based on the discharge mode of the air discharged through the outlet of the HVAC housing, the flow rate of the air guided toward the rear seats in the vehicle compartment, and the outside air temperature.

[0018] The controller can be configured to calculate the acceptable temperature difference by subtracting the temperature drop rate from the reference temperature difference.

[0019] The controller can be configured to determine a lower limit opening degree of the heating-side expansion valve based on the acceptable temperature difference, the temperature and flow rate of the refrigerant flowing into the internal condenser, and the temperature and flow rate of the air passing through the outer surface of the internal condenser.

[0020] The controller can be configured to determine the first opening degree of the heating-side expansion valve by selecting the highest opening degree among the minimum opening degree, the target opening degree, and the lower limit opening degree.

[0021] The controller can be configured to determine the second opening degree of the heating-side expansion valve by selecting the target opening degree.

[0022] According to an aspect of the present invention, a method for controlling an HVAC system of a vehicle, the HVAC system of the vehicle including a compressor, an internal condenser located downstream of the compressor and arranged in an HVAC housing, a heating-side expansion valve located downstream of the internal condenser, and a water-cooled heat exchanger located downstream of the heating-side expansion valve. The method can include: using a controller to determine an opening degree of the heating-side expansion valve based on the temperature difference between the air flowing from the internal condenser to the front seats in the vehicle compartment and the air flowing from the internal condenser to the rear seats in the vehicle compartment, and the heat (heat release amount) transferred from the internal condenser to the air.

[0023] Determining the opening degree of the heating-side expansion valve can include: using a controller to determine a first opening degree of the heating-side expansion valve according to a uniform discharge temperature mode based on the temperature difference; or can include: using a controller to determine a second opening degree of the heating-side expansion valve according to a heating enhancement mode based on the heat release amount.

[0024] Determining the opening degree of the heating-side expansion valve may include: using a controller to determine the minimum opening degree of the heating-side expansion valve based on the RPM of the compressor and the outside air temperature. In addition, determining the opening degree of the heating-side expansion valve may include: using a controller to determine the target opening degree of the heating-side expansion valve based on the RPM of the compressor, the outside air temperature, and the discharge pressure of the compressor.

[0025] Determining the opening degree of the heating-side expansion valve may include: using a controller to determine an acceptable temperature difference based on the temperature drop rate of the air flowing from the internal condenser to the rear seats in the passenger compartment.

[0026] Determining the acceptable temperature difference may include: using a controller to calculate the temperature drop rate based on the discharge mode in which the air is discharged through the outlet of the HVAC housing, the flow rate of the air guided toward the rear seats in the passenger compartment, and the outside air temperature.

[0027] Determining the acceptable temperature difference may include: using a controller to calculate the acceptable temperature difference by subtracting the temperature drop rate from a reference temperature difference.

[0028] Determining the opening degree of the heating-side expansion valve may include: using a controller to determine the lower limit opening degree of the heating-side expansion valve based on the acceptable temperature difference, the temperature and flow rate of the refrigerant flowing into the internal condenser, and the temperature and flow rate of the air passing over the outer surface of the internal condenser.

[0029] Determining the opening degree of the heating-side expansion valve may include: using a controller to determine the first opening degree of the heating-side expansion valve by selecting the highest opening degree among the minimum opening degree, the target opening degree, and the lower limit opening degree.

[0030] Determining the opening degree of the heating-side expansion valve may include: using a controller to determine the second opening degree of the heating-side expansion valve by selecting the target opening degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other objects, features, and advantages of the present invention should become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0032] Figure 1 shows the configuration of a heating, ventilation, and air conditioning (HVAC) system of a vehicle according to an embodiment of the present invention;

[0033] Figure 2 shows a graph of the relationship between the opening degree of the heating-side expansion valve, the heat release amount, and the temperature of the air guided toward the rear seats when the HVAC system of a vehicle according to an embodiment of the present invention is operating in a heating mode;

[0034] Figure 3A flowchart of a method for controlling a vehicle's HVAC system according to an embodiment of the present invention is shown.

[0035] Description of reference numerals:

[0036] 11: Heating, Ventilation, and Air Conditioning (HVAC) system

[0037] 12: Battery cooling system

[0038] 13: Power Electronics (PE) cooling system

[0039] 15: Cooling side expansion valve

[0040] 16: Chiller side expansion valve

[0041] 21: Refrigerant circulation path

[0042] 22: Battery coolant circulation path

[0043] 23: PE coolant circulation path

[0044] 26: Dehumidification bypass pipeline

[0045] 27: Shut-off valve

[0046] 30: HVAC housing

[0047] 31: Evaporator

[0048] 32: Compressor

[0049] 33: Internal condenser

[0050] 35: External heat exchanger

[0051] 36: Branch pipeline

[0052] 37: Battery chiller

[0053] 41: Battery

[0054] 42: Heater

[0055] 43: Battery radiator

[0056] 44: First battery pump

[0057] 45: Second battery pump

[0058] 46: First battery bypass pipeline

[0059] 47: Second battery bypass pipeline

[0060] 51a, 51b, 52a, 52b, 52c: PE components

[0061] 53: PE radiator

[0062] 54: PE pump

[0063] 61: Three-way valve

[0064] 70: Water-cooled heat exchanger

[0065] 75: Cooling fan

[0066] 85: Rear seat duct

[0067] 100: Controller. Detailed implementation manners

[0068] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are always used to denote the same or equivalent elements. In addition, to avoid unnecessarily obscuring the gist of the present invention, detailed descriptions of known technologies related to the present invention are omitted.

[0069] Terms such as first, second, A, B, (a), and (b) may be used to describe elements in the embodiments of the present invention. These terms are only used to distinguish one element from another, and the essential features, order, or sequence, etc. of the corresponding elements are not limited by the terms. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms defined in a commonly used dictionary should be interpreted as having a meaning consistent with the contextual meaning in the relevant field. Unless clearly defined in this application as having an ideal or overly formal meaning, these terms should not be interpreted as having an ideal or overly formal meaning.

[0070] When a controller, component, device, element, part, unit, module, etc. of the present invention is described as having a purpose or performing an operation, function, etc., the controller, component, device, element, part, unit, or module should be regarded herein as "configured to" meet the purpose or perform the operation or function. Each controller, component, device, element, part, unit, module, etc. can be implemented separately or include a processor and a memory (such as a non-volatile computer-readable medium) as part of the device.

[0071] Refer to Figure 1, according to an embodiment of the present invention, a thermal management system for a vehicle may include a heating, ventilation, and air conditioning (HVAC) system 11, which is designed to heat or cool the air in the vehicle's cabin (or passenger compartment). The system may further include: a battery cooling system 12 configured to cool the battery 41, and may include a power electronics (PE) cooling system 13 configured to cool a plurality of PE components 51a, 51b, 52a, 52b, 52c.

[0072] According to an embodiment of the present invention, a thermal management system for a vehicle may include a water-cooled heat exchanger 70, which is configured to transfer heat between a refrigerant circulation path 21 of the HVAC system 11, a battery coolant circulation path 22 of the battery cooling system 12, and a PE coolant circulation path 23 of the PE cooling system 13.

[0073] The HVAC system 11 may include a refrigerant circulation path 21 through which refrigerant circulates. The refrigerant circulation path 21 may be fluidly connected to an evaporator 31, a compressor 32, an internal condenser 33, a heating-side expansion valve 17, a water-cooled heat exchanger 70, an external heat exchanger 35, and a cooling-side expansion valve 15.

[0074] The evaporator 31 may be configured to cool air using refrigerant cooled by the external heat exchanger 35.

[0075] The compressor 32 may be configured to compress refrigerant received from the evaporator 31 and / or a battery chiller 37. According to an embodiment, the compressor 32 may be an electric compressor driven by electric energy.

[0076] The internal condenser 33 may be configured to condense the refrigerant received from the compressor 32. The refrigerant flowing through the internal channel of the internal condenser 33 may heat the air passing over the outer surface of the internal condenser 33. The air passing over the outer surface of the internal condenser 33 may be directed to the front seats and rear seats (not shown) of the vehicle's cabin (not shown), so that heating of the front seats and rear seats may be performed.

[0077] The water-cooled heat exchanger 70 may be configured to return the waste heat of the PE components 51a, 51b, 52a, 52b, 52c of the PE cooling system 13 to the HVAC system 11 and / or the battery cooling system 12 during the heating operation of the HVAC system 11. Specifically, the water-cooled heat exchanger 70 may include: a first channel 71 fluidly connected to the refrigerant circulation path 21, a second channel 72 fluidly connected to the battery coolant circulation path 22, and a third channel 73 fluidly connected to the PE coolant circulation path 23.

[0078] The water-cooled heat exchanger 70 can be configured to transfer heat between the refrigerant circulation path 21 of the HVAC system 11, the battery coolant circulation path 22 of the battery cooling system 12, and the PE coolant circulation path 23 of the PE cooling system 13. Accordingly, the refrigerant circulating in the refrigerant circulation path 21 can flow through the first channel 71 of the water-cooled heat exchanger 70. The battery coolant circulating in the battery coolant circulation path 22 of the battery cooling system 12 can flow through the second channel 72 of the water-cooled heat exchanger 70. In addition, the PE coolant circulating in the PE coolant circulation path 23 of the PE cooling system 13 can flow through the third channel 73 of the water-cooled heat exchanger 70. As a result, heat can be transferred between the refrigerant flowing through the first channel 71, the battery coolant flowing through the second channel 72, and / or the PE coolant flowing through the third channel 73. Specifically, the first channel 71 of the water-cooled heat exchanger 70 can be arranged between the internal condenser 33 and the external heat exchanger 35 in the refrigerant circulation path 21.

[0079] The water-cooled heat exchanger 70 can be configured to use the heat received from the battery cooling system 12 and the PE cooling system 13 to evaporate the refrigerant expanded by the heating-side expansion valve 17 during the heating operation of the HVAC system 11. In other words, during the heating operation of the HVAC system 11, the water-cooled heat exchanger 70 can be used as an evaporator that evaporates the refrigerant by recovering the waste heat generated by the PE components 51a, 51b, 52a, 52b, 52c of the battery cooling system 12 and the PE cooling system 13.

[0080] The water-cooled heat exchanger 70 can be configured to condense the refrigerant received from the internal condenser 33 during the cooling operation of the HVAC system 11. The water-cooled heat exchanger 70 can be used as a condenser that condenses the refrigerant by using the battery coolant circulating in the battery coolant circulation path 22 and the PE coolant circulating in the PE coolant circulation path 23 to cool the refrigerant.

[0081] The HVAC system 11 may further include a heating bypass line 78 configured such that refrigerant discharged from the first passage 71 of the water-cooled heat exchanger 70 can be directed to the compressor 32. The heating bypass line 78 may be configured to connect a downstream point of the first passage 71 of the water-cooled heat exchanger 70 and an upstream point of the compressor 32. The inlet of the heating bypass line 78 may be fluidly connected to the refrigerant circulation path 21 at a downstream point of the first passage 71 of the water-cooled heat exchanger 70. Specifically, the inlet of the heating bypass line 78 may be fluidly connected to the refrigerant circulation path 21 at a point between the outlet of the first passage 71 of the water-cooled heat exchanger 70 and the inlet of the external heat exchanger 35. The outlet of the heating bypass line 78 may be fluidly connected to the refrigerant circulation path 21 at an upstream point of the compressor 32. Specifically, the outlet of the heating bypass line 78 may be fluidly connected to the refrigerant circulation path 21 at a point between the outlet of the evaporator 31 and the inlet of the compressor 32. Additionally, the outlet of the heating bypass line 78 may be fluidly connected to the refrigerant circulation path 21 at an upstream point of the accumulator 32a or the accumulator 32a.

[0082] During the heating operation of the HVAC system 11, the heating bypass line 78 may enable the refrigerant evaporated by the water-cooled heat exchanger 70 to directly flow into the inlet of the compressor 32.

[0083] The HVAC system 11 may further include a three-way valve 77 configured to control the flow of refrigerant in a manner that selectively directs the refrigerant discharged from the first passage 71 of the water-cooled heat exchanger 70 to the external heat exchanger 35 and / or the heating bypass line 78.

[0084] The three-way valve 77 can be arranged at the connection point between the inlet of the heating bypass line 78 and the refrigerant circulation path 21. The three-way valve 77 can include: a first port 77a communicating with the first passage 71 of the water-cooled heat exchanger 70, a second port 77b communicating with the external heat exchanger 35, and a third port 77c communicating with the inlet of the heating bypass line 78. The three-way valve 77 can perform a switching operation that enables the first port 77a to selectively communicate with either the second port 77b or the third port 77c. For example, when the three-way valve 77 is switched so that the third port 77c can communicate with the first port 77a (i.e., the three-way valve 77 opens the inlet of the heating bypass line 78), the refrigerant discharged from the first passage 71 of the water-cooled heat exchanger 70 can be guided to the compressor 32 through the heating bypass line 78. In other words, when the inlet of the heating bypass line 78 is opened by the switching of the three-way valve 77, the refrigerant can bypass the external heat exchanger 35. When the three-way valve 77 is switched so that the second port 77b can communicate with the first port 77a (i.e., the three-way valve 77 closes the inlet of the heating bypass line 78), the refrigerant discharged from the first passage 71 of the water-cooled heat exchanger 70 may not flow through the heating bypass line 78 but can be guided to the external heat exchanger 35.

[0085] The heating-side expansion valve 17 can be arranged in the refrigerant circulation path 21 on the upstream side of the first passage 71 of the water-cooled heat exchanger 70. Specifically, the heating-side expansion valve 17 can be arranged between the internal condenser 33 and the water-cooled heat exchanger 70. The heating-side expansion valve 17 can regulate the flow and / or the flow rate of the refrigerant flowing into the first passage 71 of the water-cooled heat exchanger 70 during the heating operation of the HVAC system 11. In addition, the heating-side expansion valve 17 can be configured to expand the refrigerant received from the internal condenser 33 during the heating operation of the HVAC system 11.

[0086] The heating-side expansion valve 17 can be a fully open type electronic expansion valve (EXV). Accordingly, the heating-side expansion valve 17 can be fully opened during the cooling operation of the HVAC system 11 (i.e., the opening degree of the heating-side expansion valve 17 can be 100%). During the cooling operation of the HVAC system 11, the refrigerant may not expand when flowing through the heating-side expansion valve 17.

[0087] According to an embodiment, the heating-side expansion valve 17 may be an EXV having a drive motor 17a. The drive motor 17a may have a shaft that may be moved to open or close an orifice defined in the valve body of the heating-side expansion valve 17. The position of the shaft may vary according to the rotation direction, rotation degree, etc. of the drive motor 17a. Accordingly, the opening degree of the orifice of the heating-side expansion valve 17 may vary. The controller 100 may control the operation of the drive motor 17a. The opening degree of the heating-side expansion valve 17 may vary under the control of the controller 100. As the opening degree of the heating-side expansion valve 17 varies, the flow rate of the refrigerant flowing into the first passage 71 of the water-cooled heat exchanger 70 may vary. The heating-side expansion valve 17 may be controlled by the controller 100 during the heating operation of the HVAC system 11.

[0088] The external heat exchanger 35 may be adjacent to the front grille (not shown) of the vehicle. The external heat exchanger 35 may be configured to condense the refrigerant received from the internal condenser 33. In particular, the external heat exchanger 35 may be configured to use the outside air forcedly blown by the cooling fan 75 to cool the refrigerant so that the refrigerant may condense.

[0089] The external heat exchanger 35 may be adjacent to the front grille of the vehicle. The external heat exchanger 35 may be exposed to the outside air so that heat may be transferred between the external heat exchanger 35 and the outside air. An active air damper (not shown) may be provided to open or close the front grille of the vehicle. In particular, the external heat exchanger 35 may exchange heat with the outside air forcedly blown by the cooling fan 75, thereby further increasing the heat transfer rate between the external heat exchanger 35 and the outside air. During the cooling operation of the HVAC system 11, the external heat exchanger 35 may be configured to condense the refrigerant received from the internal condenser 33. In other words, during the cooling operation of the HVAC system 11, the external heat exchanger 35 may be used as a condenser that condenses the refrigerant by transferring heat to the outside air. During the heating operation of the HVAC system 11, the external heat exchanger 35 may be configured to evaporate the refrigerant received from the first passage 71 of the water-cooled heat exchanger 70 using the outside air. In other words, during the heating operation of the HVAC system 11, the external heat exchanger 35 may be used as an evaporator that evaporates the refrigerant by absorbing heat from the outside air.

[0090] The cooling-side expansion valve 15 may be arranged between the external heat exchanger 35 and the evaporator 31 in the refrigerant circulation path 21. The cooling-side expansion valve 15 may be arranged on the upstream side of the evaporator 31, so that the flow and / or the flow rate of the refrigerant flowing into the evaporator 31 can be adjusted. In addition, the cooling-side expansion valve 15 may be configured to expand the refrigerant received from the external heat exchanger 35. The cooling-side expansion valve 15 may be a thermostatic expansion valve (TXV) that senses the temperature and / or pressure of the refrigerant and adjusts the opening degree of the cooling-side expansion valve 15.

[0091] According to an embodiment of the present invention, the cooling-side expansion valve 15 may be a TXV having a shut-off valve 15a that selectively blocks or does not block the refrigerant from flowing into the internal passage of the cooling-side expansion valve 15. The shut-off valve 15a may be an electromagnetic valve. When the controller 100 controls the shut-off valve 15a, the shut-off valve 15a may be opened or closed so that the shut-off valve 15a can block or not block the refrigerant from flowing into the cooling-side expansion valve 15. When the shut-off valve 15a is opened, the refrigerant may flow into the cooling-side expansion valve 15. When the shut-off valve 15a is closed, the refrigerant may be prevented from flowing into the cooling-side expansion valve 15. According to an embodiment, the shut-off valve 15a may be installed in the valve body of the cooling-side expansion valve 15 to open or close the internal passage of the cooling-side expansion valve 15. According to another embodiment, the shut-off valve 15a may be arranged on the upstream side of the cooling-side expansion valve 15 to selectively open or close the inlet of the cooling-side expansion valve 15.

[0092] When the shut-off valve 15a is closed, the cooling-side expansion valve 15 may be blocked. Accordingly, the refrigerant is not guided to the cooling-side expansion valve 15 and the evaporator 31, but is only guided to the battery chiller 37. In other words, when the shut-off valve 15a is closed, the cooling operation of the HVAC system 11 is not performed. When the shut-off valve 15a is opened, the refrigerant may be guided to the cooling-side expansion valve 15 and the evaporator 31. In other words, when the shut-off valve 15a of the cooling-side expansion valve 15 is opened, the cooling operation of the HVAC system 11 can be performed.

[0093] The HVAC system 11 may include an HVAC housing 30 configured to blow air into the passenger compartment of the vehicle. The HVAC housing 30 may have an inlet and an outlet through which air flows in and through which air is discharged into the passenger compartment.

[0094] The evaporator 31, the internal condenser 33, and the electric heater 34 may be located in the HVAC housing 30. The evaporator 31, the internal condenser 33, and the electric heater 34 may be arranged in the HVAC housing 30 in sequence from upstream to downstream along the air flow direction. The air mixing door 39 may be arranged between the evaporator 31 and the internal condenser 33. The electric heater 34 may be arranged on the downstream side of the internal condenser 33 along the air flow direction. The electric heater 34 may be a positive temperature coefficient (PTC) heater. The electric heater 34 may operate to assist in heating the passenger compartment, thereby relatively increasing the temperature of the air blown into the passenger compartment.

[0095] The HVAC system 11 may further include a receiver 32a, which is arranged between the evaporator 31 and the compressor 32 in the refrigerant circulation path 21. The receiver 32a may be located on the downstream side of the evaporator 31. The receiver 32a may separate the liquid refrigerant from the refrigerant received from the evaporator 31, thereby preventing the liquid refrigerant from flowing into the compressor 32.

[0096] The HVAC system 11 may further include a branch pipeline 36, which enables the refrigerant discharged from the external heat exchanger 35 to be guided to the compressor 32. The inlet of the branch pipeline 36 may be fluidly connected to the refrigerant circulation path 21 at an upstream point of the expansion valve 15 on the cooling side. Specifically, the inlet of the branch pipeline 36 may be fluidly connected to the refrigerant circulation path 21 at a point between the external heat exchanger 35 and the expansion valve 15 on the cooling side. The outlet of the branch pipeline 36 may be fluidly connected to the refrigerant circulation path 21 at an upstream point of the compressor 32. Specifically, the outlet of the branch pipeline 36 may be fluidly connected to the refrigerant circulation path 21 at a point between the outlet of the evaporator 31 and the inlet of the compressor 32. In addition, the outlet of the branch pipeline 36 may be fluidly connected to the refrigerant circulation path 21 at an upstream point of the receiver 32a.

[0097] The HVAC system 11 may include a battery chiller 37 fluidly connected to the branch pipeline 36. The battery chiller 37 and the evaporator 31 may be fluidly connected in parallel to the compressor 32. The battery chiller 37 may be thermally connected to the battery cooling system 12. The battery chiller 37 may be configured to transfer heat between the refrigerant flowing through the branch pipeline 36 and the coolant flowing through the battery coolant circulation path 22. The battery chiller 37 may include a first channel 37a fluidly connected to the branch pipeline 36, and may include a second channel 37b fluidly connected to the battery coolant circulation path 22. In the battery chiller 37, the first channel 37a and the second channel 37b may be adjacent to each other or in contact with each other, and the first channel 37a may be fluidly separated from the second channel 37b. Accordingly, the battery chiller 37 may be configured to transfer heat between the coolant flowing through the second channel 37b and the refrigerant flowing through the first channel 37a.

[0098] The expansion valve 16 on the chiller side can be arranged upstream of the battery chiller 37 in the branch pipeline 36. The expansion valve 16 on the chiller side can adjust the flow and / or the flow rate of the refrigerant flowing into the battery chiller 37. The expansion valve 16 on the chiller side can be configured to expand the refrigerant received from the external heat exchanger 35.

[0099] According to an embodiment, the expansion valve 16 on the chiller side can be an EXV having a drive motor 16a. The drive motor 16a can have a shaft that can be moved to open or close an internal passage defined in the valve body of the expansion valve 16 on the chiller side. The position of the shaft can vary according to the rotation direction, rotation degree, etc. of the drive motor 16a. Accordingly, the opening degree of the internal passage of the expansion valve 16 on the chiller side can vary. The controller 100 can control the operation of the drive motor 16a.

[0100] As the opening degree of the expansion valve 16 on the chiller side varies, the flow rate of the refrigerant flowing into the battery chiller 37 can vary. For example, when the opening degree of the expansion valve 16 on the chiller side is greater than the reference opening degree, the flow rate of the refrigerant flowing into the battery chiller 37 can relatively increase above the reference flow rate. When the opening degree of the expansion valve 16 on the chiller side is less than the reference opening degree, the flow rate of the refrigerant flowing into the battery chiller 37 can be similar to the reference flow rate or relatively decrease below the reference flow rate. The reference opening degree refers to the opening degree of the expansion valve 16 on the chiller side required to maintain the target temperature of the evaporator. The reference flow rate refers to the flow rate of the refrigerant flowing into the battery chiller 37 when the expansion valve 16 on the chiller side is opened to the reference opening degree. Accordingly, when the expansion valve 16 on the chiller side is opened to the reference opening degree, the refrigerant can flow into the battery chiller 37 at the corresponding reference flow rate.

[0101] When the opening degrees of the expansion valve 15 on the cooling side and the expansion valve 16 on the chiller side are adjusted by the controller 100, the refrigerant can be distributed to the evaporator 31 and the battery chiller 37 in a predetermined ratio. Accordingly, the cooling of the HVAC system 11 and the cooling of the battery chiller 37 can be performed simultaneously or selectively. The controller 100 can be configured to control the corresponding operations of the expansion valve 15 on the cooling side, the expansion valve 16 on the chiller side, the compressor 32, etc. of the HVAC system 11. As a result, the overall operation of the HVAC system 11 can be controlled by the controller 100.

[0102] The HVAC system 11 may further include a dehumidification bypass line 26 configured to direct at least a portion of the refrigerant discharged from the heating-side expansion valve 17 to the evaporator 31. The inlet of the dehumidification bypass line 26 may be fluidly connected to the refrigerant circulation path 21 at a point between the heating-side expansion valve 17 and the first passage 71 of the water-cooled heat exchanger 70. The outlet of the dehumidification bypass line 26 may be fluidly connected to the refrigerant circulation path 21 at a point upstream of the evaporator 31. A shutoff valve 27 may be provided to open or close the dehumidification bypass line 26. When dehumidification of the passenger compartment is required during the heating operation of the HVAC system 11, the shutoff valve 27 may be opened so that at least a portion of the refrigerant flowing from the heating-side expansion valve 17 to the first passage 71 of the water-cooled heat exchanger 70 may be directed to the evaporator 31 through the dehumidification bypass line 26. Accordingly, the refrigerant directed to the evaporator 31 may absorb heat from the air passing over the outer surface of the evaporator 31. Thus, heating and dehumidification of the passenger compartment may be performed simultaneously.

[0103] The battery cooling system 12 may include a battery coolant circulation path 22 through which battery coolant circulates. The battery coolant circulation path 22 may be fluidly connected to the battery 41, the battery heater 42, the battery chiller 37, the second passage 72 of the water-cooled heat exchanger 70, the battery radiator 43, the battery reservoir 76a, the second battery pump 45, and the first battery pump 44. In Figure 1 this case, the coolant may flow sequentially through the battery 41, the battery heater 42, the battery chiller 37, the second passage 72 of the water-cooled heat exchanger 70, the battery radiator 43, the battery reservoir 76a, the second battery pump 45, and the first battery pump 44 in the battery coolant circulation path 22.

[0104] The battery 41 may have a coolant passage provided inside or outside, and the battery coolant may flow through the coolant passage. The battery coolant circulation path 22 may be fluidly connected to the coolant passage of the battery 41.

[0105] The battery heater 42 may be disposed between the battery chiller 37 and the battery 41. The battery heater 42 may have an internal passage fluidly connected to the battery coolant circulation path 22. The battery heater 42 may be configured to heat the battery coolant flowing through its internal passage. According to an embodiment, the battery heater 42 may be an electric heater. To maintain the temperature of the battery 41 at the optimum operating temperature, when preheating of the battery 41 is required, the battery heater 42 may operate, thereby heating the battery coolant. The heated battery coolant may flow through the coolant passage of the battery 41 so that the temperature of the battery 41 may be increased to the optimum operating temperature.

[0106] The battery radiator 43 can be adjacent to the front grille of the vehicle. The outside air forcedly blown by the cooling fan 75 can be used to cool the battery radiator 43. The battery radiator 43 can be adjacent to the external heat exchanger 35.

[0107] The first battery pump 44 can be configured to enable the coolant to circulate through the battery coolant circulation path 22. The first battery pump 44 can be located at an upstream point of the battery 41. Specifically, the first battery pump 44 can be fluidly connected to the battery coolant circulation path 22 at a point adjacent to the inlet of the battery 41.

[0108] The second battery pump 45 can be configured to enable the coolant to circulate through the battery coolant circulation path 22. The second battery pump 45 can be located at a downstream point of the battery radiator 43. Specifically, the second battery pump 45 can be fluidly connected to the battery coolant circulation path 22 at a point adjacent to the outlet of the battery radiator 43.

[0109] The battery cooling system 12 can include a battery reservoir 76a located at a downstream point of the battery radiator 43. The battery reservoir 76a can be located between the battery radiator 43 and the second battery pump 45. The battery reservoir 76a can temporarily store and supplement the battery coolant, so that the flow rate of the battery coolant circulating in the battery coolant circulation path 22 can be constantly maintained.

[0110] The battery cooling system 12 can further include a first battery bypass line 46 that enables the battery coolant to bypass the battery radiator 43. The first battery bypass line 46 can be configured to directly connect a downstream point and an upstream point of the battery radiator 43 in the battery coolant circulation path 22.

[0111] The inlet of the first battery bypass line 46 can be fluidly connected to the battery coolant circulation path 22 at a point between the second channel 37b of the battery chiller 37 and the battery radiator 43. Specifically, the inlet of the first battery bypass line 46 can be fluidly connected to the battery coolant circulation path 22 at a point between the second channel 37b of the battery chiller 37 and the second channel 72 of the water-cooled heat exchanger 70.

[0112] The outlet of the first battery bypass line 46 can be fluidly connected to the battery coolant circulation path 22 at a point between the battery 41 and the battery radiator 43. Specifically, the outlet of the first battery bypass line 46 can be fluidly connected to the battery coolant circulation path 22 at a point between the inlet of the first battery pump 44 and the outlet of the battery reservoir 76a.

[0113] When the battery coolant flows from the downstream side of the battery chiller 37 to the upstream side of the first battery pump 44 through the first battery bypass line 46, the battery coolant can bypass the second battery pump 45, the battery radiator 43, the battery reservoir 76a, and the second passage 72 of the water-cooled heat exchanger 70. Accordingly, the battery coolant flowing through the first battery bypass line 46 can sequentially flow through the battery 41, the battery heater 42, and the battery chiller 37 by virtue of the first battery pump 44.

[0114] The battery cooling system 12 can further include a second battery bypass line 47 that enables the battery coolant to bypass the first battery pump 44, the battery 41, the battery heater 42, and the battery chiller 37. The second battery bypass line 47 can be configured to directly connect a downstream point of the battery chiller 37 and an upstream point of the battery 41 in the battery coolant circulation path 22.

[0115] The inlet of the second battery bypass line 47 can be fluidly connected to the battery coolant circulation path 22 at a point between the outlet of the first battery bypass line 46 and the outlet of the battery radiator 43. Specifically, the inlet of the second battery bypass line 47 can be fluidly connected to the battery coolant circulation path 22 at a point between the outlet of the first battery bypass line 46 and the outlet of the second battery pump 45.

[0116] The outlet of the second battery bypass line 47 can be fluidly connected to the battery coolant circulation path 22 at a point between the inlet of the first battery bypass line 46 and the inlet of the battery radiator 43. Specifically, the outlet of the second battery bypass line 47 can be fluidly connected to the battery coolant circulation path 22 at a point between the inlet of the first battery bypass line 46 and the inlet of the second passage 72 of the water-cooled heat exchanger 70.

[0117] When the battery coolant is guided to the battery radiator 43 through the second battery bypass line 47 by virtue of the second battery pump 45, the battery coolant can bypass the battery 41, the battery heater 42, and the battery chiller 37. Accordingly, the battery coolant flowing through the second battery bypass line 47 can sequentially flow through the second passage 72 of the water-cooled heat exchanger 70, the battery radiator 43, and the battery reservoir 76a by virtue of the second battery pump 45.

[0118] The first battery bypass line 46 and the second battery bypass line 47 can be parallel to each other.

[0119] The battery cooling system 12 may further include a three-way valve 61 disposed at the inlet of the first battery bypass line 46. In other words, the three-way valve 61 may be disposed at the confluence between the inlet of the first battery bypass line 46 and the battery coolant circulation path 22. The three-way valve 61 may include: a first port 61a fluidly connected to the battery chiller 37, a second port 61b fluidly connected to the second passage 72 of the water-cooled heat exchanger 70, and a third port 61c fluidly connected to the first battery bypass line 46. The three-way valve 61 may perform a switching operation that enables at least two of the first port 61a, the second port 61b, and the third port 61c to be selectively in communication with each other. The first battery pump 44 and the second battery pump 45 may be selectively operated based on the switching operation of the three-way valve 61.

[0120] When the three-way valve 61 is switched such that the second port 61b can communicate with the first port 61a (i.e., the three-way valve 61 is switched to close the inlet of the first battery bypass line 46), the battery coolant may not flow through the first battery bypass line 46 and the second battery bypass line 47. Alternatively, the battery coolant may flow sequentially through the battery 41, the battery heater 42, the battery chiller 37, the second passage 72 of the water-cooled heat exchanger 70, and the battery radiator 43.

[0121] When the three-way valve 61 is switched such that the third port 61c can communicate with the first port 61a (i.e., the three-way valve 61a is switched to open the inlet of the first battery bypass line 46), a portion of the battery coolant may flow through the first battery bypass line 46 so that it can bypass the second battery pump 45, the second passage 72 of the water-cooled heat exchanger 70, and the battery radiator 43. Alternatively, a portion of the battery coolant may flow sequentially through the battery 41, the battery heater 42, and the battery chiller 37 by virtue of the first battery pump 44. The remaining portion of the battery coolant may flow through the second battery bypass line 47 so that it can bypass the first battery pump 44, the battery 41, the battery heater 42, and the battery chiller 37. The remaining portion of the battery coolant may flow sequentially through the second passage 72 of the water-cooled heat exchanger 70 and the battery radiator 43 by virtue of the second battery pump 45.

[0122] As described above, the three-way valve 61 may be configured to regulate the flow of the battery coolant in the battery coolant circulation path 22. The first battery pump 44 and the second battery pump 45 may be selectively operated based on the switching operation of the three-way valve 61.

[0123] The battery cooling system 12 can be controlled by the battery management system 110 and the controller 100. The battery management system 110 can monitor the state of the battery 41 and perform cooling of the battery 41 when the temperature of the battery 41 is higher than or equal to a threshold temperature. The battery management system 110 can send an instruction for cooling the battery 41 to the controller 100. Accordingly, the controller 100 can cause the compressor 32 to operate and cause the chiller side expansion valve 16 to open. When the operation of the HVAC system 11 is not required during the cooling operation of the battery 41, the controller 100 can close the cooling side expansion valve 15. In addition, the battery management system 110 can control the operation of the first battery pump 44 and the switching operation of the three-way valve 61, so that the battery coolant can bypass the battery radiator 43 and flow through the battery 41 and the battery chiller 37 as needed.

[0124] The PE cooling system 13 can be configured to cool a plurality of PE components 51a, 51b, 52a, 52b, and 52c using PE coolant circulating in the PE coolant circulation path 23.

[0125] The PE cooling system 13 can include a PE coolant circulation path 23 through which the PE coolant circulates. The PE coolant circulation path 23 can be fluidly connected to a plurality of PE components 51a, 51b, 52a, 52b, and 52c, a PE radiator 53, a PE pump 54, and a PE reservoir 76b.

[0126] According to an embodiment, the plurality of PE components can include a front wheel side motor 51a that drives the front wheels and a rear wheel side motor 51b that drives the rear wheels. The plurality of PE components can further include a front wheel side inverter 52a that controls the speed and direction of the front wheel side motor 51a, an integrated charging control unit (ICCU) 52b that charges the high-voltage battery and the auxiliary battery of the electric vehicle, and a rear wheel side inverter 52c that controls the speed and direction of the rear wheel side motor 51b.

[0127] Each of the PE components 51a, 51b, 52a, 52b, and 52c can have a coolant passage provided inside or outside. The coolant can flow through the coolant passage. The PE coolant circulation path 23 can be fluidly connected to the coolant passage of each of the PE components 51a, 51b, 52a, 52b, and 52c.

[0128] The PE radiator 53 can be adjacent to the vehicle's front grille. The outside air forcedly blown by the cooling fan 75 can be used to cool the PE radiator 53. The external heat exchanger 35, the battery radiator 43, and the PE radiator 53 can be arranged adjacent to each other at the front of the vehicle. The cooling fan 75 can be arranged behind the external heat exchanger 35, the battery radiator 43, and the PE radiator 53.

[0129] The PE pump 54 can be arranged on the upstream side of the PE components 51a, 51b, 52a, 52b, and 52c, and the PE pump 54 can enable the coolant to circulate in the PE coolant circulation path 23. The operation of the PE pump 54 can be controlled by the controller 100.

[0130] The PE reservoir 76b can be arranged on the downstream side of the PE radiator 53. In particular, the PE reservoir 76b can be arranged between the PE radiator 53 and the PE pump 54 in the PE coolant circulation path 23.

[0131] The PE cooling system 13 can further include a PE bypass line 57 that enables the PE coolant discharged from the third channel 73 of the water-cooled heat exchanger 70 to bypass the PE radiator 53 and be guided to the PE components 52a, 52b, 52c, 51a, and 51b. The PE bypass line 57 can be configured to directly connect an upstream point and a downstream point of the PE radiator 53 in the PE coolant circulation path 23. The inlet of the PE bypass line 57 can be fluidly connected to the PE coolant circulation path 23 at a point between the third channel 73 of the water-cooled heat exchanger 70 and the inlet of the PE radiator 53. The outlet of the PE bypass line 57 can be fluidly connected to the PE coolant circulation path 23 at a point between the outlet of the PE radiator 53 and the PE reservoir 76b.

[0132] The PE cooling system 13 may include a three-way valve 55 disposed at the outlet of the PE bypass line 57. The three-way valve 55 may be disposed at the confluence between the outlet of the PE bypass line 57 and the PE coolant circulation path 23. When the three-way valve 55 is switched to close the outlet of the PE bypass line 57, the PE coolant may not flow through the PE bypass line 57. Alternatively, the PE coolant may flow sequentially through the PE components 52a, 52b, 52c, 51a and 51b, the third channel 73 of the water-cooled heat exchanger 70, the PE radiator 53, and the PE liquid tank 76b. When the three-way valve 55 is switched to open the outlet of the PE bypass line 57, the PE coolant may flow through the PE bypass line 57 so that it can bypass the PE radiator 53. As a result, the PE coolant may flow sequentially through the PE components 52a, 52b, 52c, 51a and 51b, the third channel 73 of the water-cooled heat exchanger 70, and the PE liquid tank 76b. The three-way valve 55 may regulate the flow of the PE coolant in the PE coolant circulation path 23.

[0133] According to an embodiment, the battery liquid tank 76a and the PE liquid tank 76b may be joined to form an integral liquid tank 76. The battery liquid tank 76a and the PE liquid tank 76b may be fluidly separated from each other by a partition or the like.

[0134] According to another embodiment, the battery liquid tank 76a and the PE liquid tank 76b may be fluidly connected to each other in the integral liquid tank 76. Accordingly, the battery coolant and the PE coolant may be mixed in the integral liquid tank 76.

[0135] The vehicle thermal management system according to an embodiment of the present invention may include: an outside air temperature sensor (not shown) for measuring the outside air temperature of the vehicle, a coolant temperature sensor (not shown) for measuring the temperature of the coolant circulating in the battery coolant circulation path, a refrigerant pressure / temperature sensor (not shown) for measuring the pressure and temperature of the low-pressure refrigerant, an evaporator temperature sensor (not shown) disposed adjacent to the evaporator, and an interior temperature sensor (not shown) for measuring the interior temperature of the passenger compartment.

[0136] The outside air temperature sensor may be adjacent to the front grille of the vehicle so that it can measure the outside air temperature of the vehicle. The outside air temperature measured by the outside air temperature sensor may be used for the optimal control of the HVAC system 11 and the battery cooling system 12.

[0137] The coolant temperature sensor can be disposed in the battery coolant circulation path 22 and can measure the temperature of the coolant circulating in the battery coolant circulation path 22. The temperature of the coolant measured by the coolant temperature sensor can be used for the optimal control of the HVAC system 11 and the battery cooling system 12. According to an embodiment, the coolant temperature sensor can be arranged on the downstream side of the battery radiator 43 in the battery coolant circulation path 22. In Figure 1 this case, the coolant temperature sensor can be located between the outlet of the battery radiator 43 and the inlet of the second battery pump 45.

[0138] The refrigerant pressure / temperature sensor can be located on the downstream side of the battery chiller 37 and can measure the pressure and temperature of the low-pressure refrigerant expanded by the chiller-side expansion valve 16. The pressure and temperature of the refrigerant measured by the refrigerant pressure / temperature sensor can be used for the optimal control of the HVAC system 11 and the battery cooling system 12.

[0139] The evaporator temperature sensor can be disposed on the outer surface of the evaporator 31 or can be adjacent to the evaporator 31. The evaporator temperature sensor can measure the temperature of the evaporator 31 and the temperature of the air passing through the outer surface of the evaporator 31. The temperature of the evaporator 31 and the temperature of the air passing through the outer surface of the evaporator 31 measured by the evaporator temperature sensor can be used for the optimal control of the HVAC system 11 and the battery cooling system 12.

[0140] The interior temperature sensor can be disposed in the passenger compartment and can measure the interior temperature of the passenger compartment. The interior temperature of the passenger compartment measured by the interior temperature sensor can be used for the optimal control of the HVAC system 11 and the battery cooling system 12.

[0141] The controller 100 can use the information received from various sensors such as the outside air temperature sensor, the coolant temperature sensor, the refrigerant pressure / temperature sensor, the evaporator temperature sensor, and the interior temperature sensor to appropriately control the operations of the HVAC system 11, the battery cooling system 12, and the PE cooling system 13. For example, the controller 100 can control the operations of the shut-off valve 15a of the cooling-side expansion valve 15, the electric heater 34, the air mix door 39, the compressor 32, the cooling fan 75, the drive motor 16a of the chiller-side expansion valve 16, the drive motor 17a of the heating-side expansion valve 17, the first battery pump 44, the second battery pump 45, the PE pump 54, the three-way valves 55, 61, and 77, etc. As a result, the cooling and heating of the passenger compartment, the cooling of the battery 41, and the cooling of the PE components 51a, 51b, 52a, 52b, and 52c can be appropriately performed. According to an embodiment, the controller 100 can be a full automatic temperature control (FATC) system or a dual automatic temperature control (DATC) system.

[0142] The controller 100 may include a processor and a memory. The processor may be programmed to receive instructions stored in the memory. The processor may send the instructions to the HVAC system 11, the battery cooling system 12, and the PE cooling system 13. The memory may be a data storage device such as a hard disk drive, a solid state drive, a server, a volatile storage medium, and a non-volatile memory medium.

[0143] When the HVAC system 11 operates in a heating mode to heat the passenger compartment, the shut-off valve 15a of the cooling-side expansion valve 15 may be closed, the opening degree of the heating-side expansion valve 17 may be adjusted, and the three-way valve 77 may be switched to connect the third port 77c to the first port 77a. The refrigerant compressed by the compressor 32 may be condensed in the internal condenser 33. The refrigerant condensed by the internal condenser 33 may expand in the heating-side expansion valve 17. The expanded refrigerant may evaporate in the first channel 71 of the water-cooled heat exchanger 70, and the evaporated refrigerant may be guided to the compressor 32 through the heating bypass line 78. In other words, the refrigerant may flow through the compressor 32, the internal condenser 33, the heating-side expansion valve 17, and the water-cooled heat exchanger 70 in sequence. The air passing through the outer surface of the internal condenser 33 may be heated by the refrigerant flowing through the internal channel of the internal condenser 33. The heated air may be guided toward the front seats of the passenger compartment through the outlet of the HVAC housing 30, and the heated air may be guided toward the rear seats of the passenger compartment through the rear seat duct 85, so that the heating of the front seats and the rear seats of the passenger compartment may be performed.

[0144] To avoid operational limitations caused by a pressure drop of the refrigerant, the internal condenser 33 may be configured such that the refrigerant can flow in one direction. Accordingly, the temperature of the air passing through the outer surface of the internal condenser 33 may be different depending on the flow direction of the refrigerant. For example, the internal condenser 33 may have an inlet header located above the outlet header, and a plurality of tubes may be configured to connect the inlet header and the outlet header. When the refrigerant flows from the inlet header to the outlet header through the plurality of tubes, a temperature difference may occur between the air passing through the upper portion of the internal condenser 33 and the air passing through the lower portion of the internal condenser 33. The air passing through the upper portion of the internal condenser 33 may be guided toward the front seats of the passenger compartment through the outlet of the HVAC housing 30. The air passing through the lower portion of the internal condenser 33 may be guided toward the rear seats of the passenger compartment through the rear seat duct 85, so that a temperature difference may occur between the air guided toward the front seats of the passenger compartment and the air guided toward the rear seats of the passenger compartment. Herein, the term "temperature difference" is used to represent the temperature difference between the air flowing from the internal condenser 33 to the front seats of the passenger compartment and the air flowing from the internal condenser 33 to the rear seats of the passenger compartment.

[0145] In a state where the HVAC system 11 is operating in a heating mode, when the opening degree of the heating-side expansion valve 17 increases, the flow resistance of the refrigerant will relatively decrease. Since the difference between the suction pressure (suction temperature) and the discharge pressure (discharge temperature) of the compressor 32 relatively decreases, the temperature and pressure of the refrigerant flowing into the internal condenser 33 will decrease, and the flow rate of the refrigerant flowing into the internal condenser 33 will increase. In other words, as the opening degree of the heating-side expansion valve 17 increases, the temperature and pressure of the refrigerant flowing into the internal condenser 33 will relatively decrease. As Figure 2 shown, as the opening degree of the heating-side expansion valve 17 increases, the amount of heat Q transferred from the internal condenser 33 to the air (hereinafter referred to as "heat release amount Q") will relatively decrease, and the temperature Tr of the air guided toward the rear seats of the passenger compartment will relatively increase.

[0146] Referring to Figure 2 , as the opening degree of the heating-side expansion valve 17 increases, the heat release amount Q will relatively decrease. Accordingly, the passenger compartment heating performance of the HVAC system 11 will decrease. In addition, as the opening degree of the heating-side expansion valve 17 decreases, the heat release amount Q will relatively increase, and accordingly, the passenger compartment heating performance of the HVAC system 11 can be improved. In other words, the heat release amount Q and the passenger compartment heating performance of the HVAC system 11 can be inversely proportional to the opening degree of the heating-side expansion valve 17. In addition, as the opening degree of the heating-side expansion valve 17 increases, the temperature Tr of the air guided toward the rear seats will relatively increase, thereby reducing the temperature difference. As the opening degree of the heating-side expansion valve 17 decreases, the temperature Tr of the air guided toward the rear seats will relatively decrease, thereby increasing the temperature difference. In other words, the temperature Tr of the air guided toward the rear seats of the passenger compartment can be directly proportional to the opening degree of the heating-side expansion valve 17. In addition, the temperature difference can be inversely proportional to the opening degree of the heating-side expansion valve 17.

[0147] Referring to Figure 2 , when the opening degree of the heating-side expansion valve 17 is higher than the lower limit opening degree c, the heat release amount Q (i.e., the amount of heat released) will relatively decrease, and the temperature Tr of the air flowing from the internal condenser 33 to the rear seats will relatively increase, thereby relatively reducing the temperature difference. When the opening degree of the heating-side expansion valve 17 is lower than the lower limit opening degree c, the heat release amount Q will relatively increase, but the temperature Tr of the air flowing from the internal condenser 33 to the rear seats will relatively decrease, thereby relatively increasing the temperature difference. The lower limit Th of the temperature Tr of the air flowing from the internal condenser 33 to the rear seats can correspond to the lower limit opening degree c of the heating-side expansion valve 17. In addition, the lower limit Th of the temperature Tr of the air is the temperature corresponding to an acceptable temperature difference. In other words, the lower limit opening degree c is the limit of the opening degree of the heating-side expansion valve 17 corresponding to an acceptable temperature difference. As described above, based on the lower limit opening degree c of the heating-side expansion valve 17, the passenger compartment heating performance and the temperature difference may conflict with each other.

[0148] According to an embodiment of the present invention, when the HVAC system 11 operates in the heating mode, a passenger can select either a uniform discharge temperature mode or a heating enhancement mode. The uniform discharge temperature mode refers to a mode in which the temperature difference is minimized so that the temperature of the front row seats and the temperature of the rear row seats can become uniform. The heating enhancement mode refers to a mode in which both the amount of heat released from the internal condenser 33 to the air and the associated heating performance are maximized regardless of the temperature difference. The controller 100 can adjust the opening degree of the heating-side expansion valve 17 based on the temperature difference between the air flowing from the internal condenser 33 to the front row seats in the vehicle compartment and the air flowing from the internal condenser 33 to the rear row seats in the vehicle compartment. In addition, the controller 100 can adjust the opening degree of the heating-side expansion valve 17 based on the amount of heat release Q from the internal condenser 33 to the air.

[0149] According to an embodiment of the present invention, the controller 100 can be configured to determine a first opening degree of the heating-side expansion valve 17 according to the uniform discharge temperature mode based on the temperature difference, or can be configured to determine a second opening degree of the heating-side expansion valve 17 according to the heating enhancement mode based on the amount of heat release Q. When the HVAC system 11 operates in the heating mode, the controller 100 can adjust the opening degree of the heating-side expansion valve 17 to either the uniform discharge temperature mode or the heating enhancement mode. Accordingly, the HVAC system 11 can appropriately handle the conflict between the vehicle compartment heating performance and the temperature difference.

[0150] Referring to Figure 3 , the HVAC system 11 can operate in the heating mode (S1). The controller 100 can determine a minimum opening degree a of the heating-side expansion valve 17 based on the revolutions per minute (RPM) of the compressor 32 and the outside air temperature Tb (S2).

[0151] The controller 100 can determine a target opening degree b of the heating-side expansion valve 17 based on the RPM of the compressor 32, the outside air temperature Tb, and the discharge pressure Ph of the compressor 32 (S3). The target opening degree b can be higher than the minimum opening degree a.

[0152] The controller 100 can determine whether the passenger has selected the uniform discharge temperature mode (S4). In the case where the passenger occupies both the front row seats and the rear row seats in the vehicle compartment, the uniform discharge temperature mode can be selected to uniformly maintain the temperature of the front row seats and the temperature of the rear row seats.

[0153] When the controller 100 determines that the passenger has selected the uniform discharge temperature mode, the controller 100 can calculate a temperature drop rate d, that is, the temperature drop of the air flowing from the internal condenser 33 to the rear row seats in the vehicle compartment (S5). Specifically, the temperature drop rate d refers to the temperature drop rate of the air temperature reduced when the air is guided from the internal condenser 33 to the rear row seats in the vehicle compartment through the rear row seat duct 85.

[0154] According to an embodiment, based on the discharge mode in which air heated by the internal condenser 33 is discharged through the outlet of the HVAC housing 30, the flow rate Fr of the air guided to the rear seats of the passenger compartment through the rear seat ducts 85, and the outside air temperature Tb, the controller 100 may calculate the temperature drop rate d.

[0155] The controller 100 may calculate an acceptable temperature difference f (f = e - d) by subtracting the temperature drop rate d from a predetermined reference temperature difference e (S6). The reference temperature difference e refers to the maximum temperature difference that a passenger can tolerate or accept. The reference temperature difference e may be determined in advance according to the vehicle specifications, external environmental conditions, heating settings of the HVAC system 11, etc. The reference temperature difference e may be pre-input into the memory of the controller 100. The acceptable temperature difference f may be the acceptable temperature difference on the downstream side of the internal condenser 33.

[0156] The controller 100 may apply the acceptable temperature difference f, the temperature Tr and flow rate Fc of the refrigerant flowing into the internal condenser 33, and the temperature Ta and flow rate Fa of the air passing through the outer surface of the internal condenser 33 to a map (S7). The controller 100 may determine the lower limit opening c of the heating-side expansion valve 17 through the map (S8). The map may be map data including the opening of the heating-side expansion valve 17 and the corresponding temperature difference. In other words, based on the acceptable temperature difference f, the temperature Tr and flow rate Fc of the refrigerant flowing into the internal condenser 33, and the temperature Ta and flow rate Fa of the air passing through the outer surface of the internal condenser 33, the controller 100 may determine the lower limit opening c of the heating-side expansion valve 17.

[0157] The controller 100 may select the highest opening among the minimum opening a, the target opening b, and the lower limit opening c. As a result, the controller may determine the first opening of the heating-side expansion valve 17 so that the HVAC system 11 operates in a uniform discharge temperature mode (S9). The controller 100 may determine the first opening of the heating-side expansion valve 17 so as to minimize the temperature difference between the air flowing from the internal condenser 33 toward the front seats and the air flowing from the internal condenser 33 toward the rear seats. As a result, the HVAC system 11 may operate in a uniform discharge temperature mode, in which the temperatures of the front seats and the rear seats become uniform.

[0158] When the controller 100 determines in S4 that the uniform discharge temperature mode is not selected, the heating enhancement mode can be automatically selected to maximize the cabin heating performance of the HVAC system 11. Accordingly, the controller 100 can open or close the outlet of the HVAC housing 30 or the outlet of the rear seat duct 85 so that the air heated by the internal condenser 33 can be guided to the front seats or the rear seats. When it is determined in S4 that the uniform discharge temperature mode is not selected, the controller 100 can select the target opening degree b to determine the second opening degree of the heating-side expansion valve 17 so that the HVAC system 11 operates in the heating enhancement mode (S10).

[0159] As described above, according to an embodiment of the present invention, when the HVAC system operates in the heating mode, the controller can adjust the opening degree of the heating-side expansion valve to any one of the selected uniform discharge temperature mode and the heating enhancement mode. Accordingly, the HVAC system can appropriately handle the conflict between the cabin heating performance and the temperature difference.

[0160] In the above, although the present invention has been described with reference to the embodiments and the drawings, the present invention is not limited thereto. Various modifications and changes can be made by those of ordinary skill in the art to which the present invention pertains without departing from the spirit and scope of the present invention protected by the claims.

Claims

1. A HVAC system for a vehicle, the HVAC system for the vehicle comprising: compressor; an internal condenser located downstream of the compressor and disposed in the HVAC housing; a heating-side expansion valve located on the downstream side of the internal condenser; a water-cooled heat exchanger located downstream of the heating-side expansion valve; as well as A controller is configured to adjust the opening of the heating-side expansion valve based on a temperature difference between air flowing from the interior condenser to front seats of a vehicle cabin and air flowing from the interior condenser to rear seats of the vehicle cabin and heat transferred from the interior condenser to the air.

2. The HVAC system of a vehicle according to claim 1, wherein: The controller is configured as follows: determining a first opening degree of the heating-side expansion valve according to a uniform discharge temperature pattern based on the temperature difference; or The second opening degree of the heating-side expansion valve is determined according to the heating enhancement mode based on the heat release amount.

3. The HVAC system for a vehicle according to claim 1, wherein: The controller is configured to: determine a minimum opening degree of the heating-side expansion valve based on the revolutions per minute of the compressor and the outside air temperature; The controller is configured to determine a target opening degree of the heating-side expansion valve based on the revolutions per minute of the compressor, an outside air temperature, and a discharge pressure of the compressor.

4. The HVAC system of a vehicle according to claim 3, wherein: The controller is configured to determine an acceptable temperature difference based on a rate of temperature drop of air flowing from an interior condenser to rear seats of a vehicle cabin.

5. The HVAC system for a vehicle according to claim 4, wherein: The controller is configured to calculate the temperature drop rate based on a discharge pattern of air discharged through an outlet of the HVAC housing, a flow rate of air directed toward a rear seat of a vehicle cabin, and an outside air temperature.

6. The HVAC system for a vehicle according to claim 4, wherein: The controller is configured to calculate the acceptable temperature difference by subtracting the temperature drop rate from a reference temperature difference.

7. The HVAC system for a vehicle according to claim 6, wherein: The controller is configured to determine a lower limit opening degree of the heating-side expansion valve based on the acceptable temperature difference, the temperature and flow rate of the refrigerant flowing into the interior condenser, and the temperature and flow rate of the air passing through the outer surface of the interior condenser.

8. The HVAC system for a vehicle according to claim 7, wherein: The controller is configured to determine a first opening degree of the heating-side expansion valve by selecting a highest opening degree among the minimum opening degree, the target opening degree, and the lower limit opening degree.

9. The HVAC system for a vehicle according to claim 3, wherein: The controller is configured to determine a second opening degree of the heating-side expansion valve by selecting the target opening degree.

10. A method for controlling an HVAC system of a vehicle, the HVAC system of the vehicle comprising a compressor, an interior condenser located on a downstream side of the compressor and arranged in an HVAC housing, a heating-side expansion valve located on a downstream side of the interior condenser, and a water-cooled heat exchanger located on a downstream side of the heating-side expansion valve, the method comprising: With the controller, the opening degree of the heating-side expansion valve is determined based on the temperature difference between air flowing from the interior condenser to the front seats of the vehicle cabin and air flowing from the interior condenser to the rear seats of the vehicle cabin and the heat transferred from the interior condenser to the air.

11. The method according to claim 10, wherein: Determining the opening of the heating side expansion valve includes: Determining, by a controller, a first opening degree of the heating-side expansion valve according to a uniform discharge temperature pattern based on a temperature difference; or The second opening degree of the heating-side expansion valve is determined by the controller according to the heating enhancement mode based on the heat release amount.

12. The method according to claim 10, wherein: Determining the opening of the heating side expansion valve includes: Determining, by a controller, a minimum opening degree of the heating-side expansion valve based on the revolutions per minute of the compressor and the outside air temperature; The target opening degree of the heating-side expansion valve is determined by the controller based on the revolutions per minute of the compressor, the outside air temperature, and the discharge pressure of the compressor.

13. The method according to claim 12, wherein: Determining the opening degree of the heating-side expansion valve includes determining, by a controller, an acceptable temperature difference based on a temperature drop rate of air flowing from an interior condenser to a rear seat of a vehicle cabin.

14. The method according to claim 13, wherein: Determining the acceptable temperature difference includes calculating, by the controller, the temperature drop rate based on a discharge pattern of air discharged through an outlet of the HVAC housing, a flow rate of air directed toward rear seats of the vehicle cabin, and an outside air temperature.

15. The method according to claim 13, wherein: Determining the acceptable temperature difference includes: calculating, by a controller, the acceptable temperature difference by subtracting the temperature drop rate from a reference temperature difference.

16. The method according to claim 15, wherein: Determining the opening of the heating side expansion valve includes: using a controller to determine the lower limit opening of the heating side expansion valve based on the acceptable temperature difference, the temperature and flow rate of the refrigerant flowing into the internal condenser, and the temperature and flow rate of the air passing through the outer surface of the internal condenser.

17. The method according to claim 16, wherein: Determining the opening degree of the heating-side expansion valve includes: using a controller to determine a first opening degree of the heating-side expansion valve by selecting a maximum opening degree among the minimum opening degree, the target opening degree, and the lower limit opening degree.

18. The method according to claim 12, wherein: Determining the opening degree of the heating-side expansion valve includes: using a controller to determine a second opening degree of the heating-side expansion valve by selecting the target opening degree.

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