Vehicle heating, ventilation and air conditioning system

Abstract

The present invention relates to a vehicle heating, ventilation and air conditioning system, comprising: a compressor; an internal condenser provided on the downstream side of the compressor; a heat exchanger disposed on a downstream side of the internal condenser, in which the heat exchanger is configured to transfer heat between the refrigerant and the coolant circulating in the coolant system; an evaporator provided on the downstream side of the heat exchanger and on the upstream side of the compressor; a first bypass line connecting a downstream point of the heat exchanger and an upstream point of the compressor; and a second bypass line connecting a downstream point of the internal condenser and an upstream point of the evaporator.

Description

[0001] Cross-references to related applications

[0002] This application is based on and claims the priority of Korean Patent Application No. 10-2024-0160361, filed with the Korean Intellectual Property Office on November 12, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a vehicle heating, ventilation and air conditioning (HVAC) system. Background Technology

[0004] In recent years, with increasing attention to energy efficiency and environmental issues, there has been a need to develop environmentally friendly vehicles that can replace internal combustion engine vehicles. These environmentally friendly vehicles are divided into electric vehicles that use fuel cells or electricity as a power source and hybrid vehicles that use both engines and batteries.

[0005] Electric or hybrid vehicles may include a heating, ventilation, and air conditioning (HVAC) system for air conditioning the passenger compartment (or passenger cabin). This HVAC system can be configured to heat and cool the air in the passenger compartment to ensure passenger comfort.

[0006] To ensure driving safety, electric or hybrid vehicles may include a PE cooling system that maintains the PE components of the power electronics (PE) system at an appropriate temperature, and a battery cooling system that maintains the battery at an appropriate temperature. The PE cooling system can cool PE components, such as the motor, inverter, on-board charger (OBC), and low-voltage DC-DC converter (LDC), thereby maintaining the PE components at their respective appropriate temperatures. The battery cooling system can cool the battery, thereby maintaining the battery at its appropriate temperature.

[0007] The refrigerant circulating in the HVAC system of an electric vehicle can be configured to absorb heat from the PE coolant circulating in the PE cooling system and be evaporated via a water-cooled heat exchanger.

[0008] However, under relatively low ambient temperatures (e.g., -20°C to -5°C), the temperature of the PE refrigerant may decrease relatively, thus preventing the refrigerant from fully absorbing heat from the PE refrigerant. Consequently, refrigerant evaporation decreases, and the compressor suction pressure may drop below the threshold pressure. When the compressor suction pressure falls below the threshold pressure (e.g., 0.2 kgf / cm²), the refrigerant's evaporation decreases. 2When refrigerant flow is interrupted, the compressor's efficiency decreases, potentially causing the compressor's RPM to drop below the threshold RPM, or the compressor to stop due to low-pressure protection. Consequently, the refrigerant flow rate may decrease relatively, and the temperature of the refrigerant discharged from the compressor may also decrease, potentially degrading the HVAC system's coefficient of performance (COP). Furthermore, since heating the passenger compartment using refrigerant is not feasible and is instead achieved through electric heaters, the electrical efficiency of electric vehicles may be reduced.

[0009] In existing HVAC systems, the refrigerant's heat absorption decreases at relatively low ambient temperatures, potentially leading to a relative decrease in compressor suction pressure. Consequently, as the compressor's RPM decreases or stops, refrigerant heating of the passenger compartment may not function smoothly, potentially requiring an electric heater and reducing the electric efficiency of the electric vehicle.

[0010] The information described in this background section is provided to aid in understanding the background of the invention and may include technical concepts that are not considered to be prior art that has been disclosed, is known, is available, or is in use. Summary of the Invention

[0011] This invention relates to a vehicle heating, ventilation and air conditioning (HVAC) system, and more particularly to a vehicle HVAC system designed to use a refrigerant to improve heating performance, thereby improving the electrical efficiency of an electric vehicle.

[0012] The embodiments of the present invention can solve the above-mentioned problems in the prior art, while maintaining the advantages of the prior art.

[0013] Embodiments of the present invention may provide a vehicle heating, ventilation and air conditioning (HVAC) system designed to use refrigerant to improve heating performance, thereby improving the electrical efficiency of electric vehicles.

[0014] According to an embodiment of the present invention, a vehicle HVAC system may include: a compressor; an internal condenser disposed downstream of the compressor; a heat exchanger disposed downstream of the internal condenser and configured to transfer heat between a refrigerant and a coolant circulating in a coolant system; an evaporator disposed downstream of the heat exchanger and upstream of the compressor; a first bypass line connecting a downstream point of the heat exchanger and an upstream point of the compressor; and a second bypass line connecting a downstream point of the internal condenser and an upstream point of the evaporator.

[0015] The vehicle HVAC system may also include an external heat exchanger disposed between the heat exchanger and the evaporator, and configured to transfer heat between the refrigerant and ambient air. A first bypass line may be configured such that at least a portion of the refrigerant discharged from the heat exchanger is directed from an upstream point of the external heat exchanger to an upstream point of the compressor.

[0016] The vehicle HVAC system may also include: a cooling-side expansion valve disposed between the external heat exchanger and the evaporator; and a heating-side expansion valve disposed between the heat exchanger and the internal condenser. A second bypass line may be configured such that at least a portion of the refrigerant discharged from the internal condenser can be guided from an upstream point of the heating-side expansion valve to an upstream point of the evaporator.

[0017] The vehicle HVAC system may also include a control valve configured to control the flow of refrigerant in such a way that refrigerant discharged from the heat exchanger can be directed to at least one of the external heat exchanger and the compressor.

[0018] The control valve may include: an inlet connected to a heat exchanger; a first outlet connected to an external heat exchanger; and a second outlet connected to a first bypass line.

[0019] The control valve can be switched so that the inlet can be fluidly connected to at least one of the first outlet and the second outlet.

[0020] When the HVAC system is operating in heating mode, the control valve can be switched so that the inlet can be fluidly connected to the second outlet.

[0021] The vehicle's HVAC system may also include an auxiliary expansion valve located on a second bypass line. The auxiliary expansion valve may be located upstream of the evaporator on the second bypass line.

[0022] When the HVAC system is running in heating mode, the auxiliary expansion valve can be fully opened.

[0023] The vehicle's HVAC system may also include a regulating valve positioned between the evaporator and the compressor. The regulating valve can adjust its opening to regulate the flow rate of refrigerant discharged from the evaporator.

[0024] A heat exchanger may include a first channel through which refrigerant passes and a second channel through which coolant passes. The second channel of the heat exchanger may be fluidly connected to a power electronics (PE) coolant system. Attached Figure Description

[0025] The above and other features and advantages of exemplary embodiments of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1A vehicle heating, ventilation, and air conditioning (HVAC) system according to an example embodiment of the present invention is shown;

[0027] Figure 2 This illustrates the flow of refrigerant when a vehicle HVAC system according to an example embodiment of the present invention is operating in heating mode;

[0028] Figure 3 This illustrates the flow of refrigerant when the vehicle HVAC system according to an example embodiment of the invention is operating in cooling mode; and

[0029] Figure 4 This illustrates the flow of refrigerant when a vehicle HVAC system according to an example embodiment of the present invention is operating in back-blowing mode. Detailed Implementation

[0030] In the following, exemplary embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals may be used to denote the same or equivalent elements. Detailed descriptions of well-known techniques associated with the invention are omitted so as not to unnecessarily obscure the essential points of the invention.

[0031] Terms such as “first,” “second,” “A,” “B,” “(a),” and “(b)” may be used to describe elements in exemplary embodiments of the invention. These terms may be used only to distinguish one element from another, and the inherent characteristics, order, or sequence of the corresponding elements are not necessarily limited by these terms. Unless otherwise defined, the terms used herein (including technical or scientific terms) may have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries may be interpreted as having a meaning equivalent to that in the context of the relevant field.

[0032] refer to Figure 1 According to an exemplary embodiment of the present invention, a vehicle heating, ventilation, and air conditioning (HVAC) system can be configured to heat and cool the air in the vehicle's cabin (or passenger compartment) by means of a phase change in a circulating refrigerant. The HVAC system may include a refrigerant circulation path 30 through which the refrigerant circulates, and an HVAC housing 20. The refrigerant circulation path 30 may be fluidly connected to a compressor 11, an internal condenser 12, a heat exchanger 13, an external heat exchanger 14, a cooling-side expansion valve 15, and an evaporator 16. The refrigerant circulation path 30 is capable of altering the flow of the refrigerant according to various operating modes of the vehicle's thermal management system.

[0033] Compressor 11 can compress refrigerant and circulate the refrigerant. Specifically, compressor 11 can be configured to compress refrigerant received from evaporator 16 and / or battery cooler 18. Compressor 11 may include a compressor motor and a compression section operated by the compressor motor. Refrigerant circulation path 30 may be fluidly connected to the compression section of compressor 11.

[0034] The HVAC system may include a receiver 17 located upstream of the compressor 11. The receiver 17 may be located between the evaporator 16 and the compressor 11, and the receiver 17 can separate the liquid refrigerant from the refrigerant received from the evaporator 16, thereby preventing the liquid refrigerant from flowing into the compressor 11.

[0035] An internal condenser 12 may be located downstream of the compressor 11 and is configured to condense the refrigerant received from the compressor 11. That is, the refrigerant compressed by the compressor 11 can transfer heat to the air and condense in the internal condenser 12. Therefore, the internal condenser 12 can use the refrigerant compressed by the compressor 11 to heat the air. When the air heated by the internal condenser 12 is directed into the passenger compartment, the passenger compartment can be heated. The internal condenser 12 corresponds to the heater core of the HVAC system in an internal combustion engine vehicle.

[0036] The heat exchanger 13 may be located downstream of the internal condenser 12, and the heat exchanger 13 may be thermally connected to the power electronics (PE) coolant system 50. The heat exchanger 13 may be configured to transfer heat between the PE coolant circulating in the PE coolant system 50 and the refrigerant circulating in the refrigerant circulation path 30.

[0037] According to an example embodiment, the PE coolant system 50 may include: a PE coolant circulation path 51 through which PE coolant circulates, a PE component 52 fluidly connected to the PE coolant circulation path 51, a PE pump 53 forcing PE coolant circulation, and a PE radiator 54 fluidly connected to the PE coolant circulation path 51. The PE component may be a motor, inverter, power conversion component, etc. The PE radiator 54 may be positioned adjacent to the front grille of the vehicle, and the PE coolant passing through the PE radiator 54 may be cooled by ambient air forced in by a cooling fan. The PE component 52 may have coolant passages disposed inside or outside it, and PE coolant may pass through these coolant passages. The coolant passages of the PE component 52 may be fluidly connected to the PE coolant circulation path 51.

[0038] The heat exchanger 13 may include a first channel 13a fluidly connected to the refrigerant circulation path 30 and a second channel 13b fluidly connected to the PE coolant circulation path 51. When the temperature of the PE assembly rises, the PE coolant can absorb heat from the PE assembly, causing the temperature of the PE coolant to rise relatively. The refrigerant passing through the first channel 13a of the heat exchanger 13 can exchange heat with the PE coolant passing through the second channel 13b of the heat exchanger 13.

[0039] An external heat exchanger 14 can be disposed downstream of the first channel 13a of the heat exchanger 13, and can also be disposed upstream of the evaporator 16. That is, the external heat exchanger 14 can be disposed between the first channel 13a of the heat exchanger 13 and the evaporator 16. The external heat exchanger 14 can have a refrigerant channel disposed therein, and refrigerant can pass through the refrigerant channel. The external heat exchanger 14 can be disposed adjacent to the front grille of the vehicle, and can be exposed to the outside. In particular, the external heat exchanger 14 can exchange heat with ambient air forced by the cooling fan 24, thereby further increasing the heat transfer rate between the refrigerant and the air. (Reference) Figure 3 During cooling operation of the HVAC system, the external heat exchanger 14 can be configured to condense the refrigerant received from the internal condenser 12. That is, the external heat exchanger 14 can function as an external condenser that condenses the refrigerant by releasing heat from the refrigerant to the ambient air during cooling operation of the HVAC system. (Reference) Figure 2 During the heating operation of the HVAC system, refrigerant can be prevented from flowing into the external heat exchanger 14.

[0040] The cooling-side expansion valve 15 can be located downstream of the external heat exchanger 14 and upstream of the evaporator 16. That is, the cooling-side expansion valve 15 can be located between the external heat exchanger 14 and the evaporator 16. The cooling-side expansion valve 15 can regulate the flow of refrigerant and / or the flow rate of refrigerant entering the evaporator 16. When the HVAC system is operating in cooling mode, the cooling-side expansion valve 15 can open to a set, selected, or predetermined opening degree to allow the refrigerant guided to the evaporator 16 to expand.

[0041] According to an example embodiment, the cooling-side expansion valve 15 may be a thermal expansion valve (TXV) that senses the temperature and / or pressure of the refrigerant and adjusts the opening of the cooling-side expansion valve 15. When the cooling-side expansion valve 15 is used as a TXV, a solenoid valve may be disposed in the cooling-side expansion valve 15 or on the upstream side of the cooling-side expansion valve 15.

[0042] According to an example embodiment, the cooling-side expansion valve 15 may be an electronic expansion valve (EXV) with an actuator. The actuator may have a shaft that is movable to open or close an orifice defined in the valve body of the cooling-side expansion valve 15, and the position of the shaft may vary depending on the direction and degree of rotation of the actuator, thus the opening degree of the orifice of the cooling-side expansion valve 15 may vary. A controller may control the operation of the actuator.

[0043] The evaporator 16 can be located downstream of the cooling-side expansion valve 15 and configured to receive refrigerant expanded by the cooling-side expansion valve 15. The evaporator 16 can be configured to use the refrigerant received from the cooling-side expansion valve 15 to cool air. That is, the refrigerant expanded by the cooling-side expansion valve 15 can absorb heat from the air and evaporate in the evaporator 16. During cooling operation of the HVAC system, the evaporator 16 can be configured to cool the air flowing into the vehicle compartment using the refrigerant cooled by the external heat exchanger 14 and expanded by the cooling-side expansion valve 15. The evaporator 16 can be located upstream of the compressor 11, and the refrigerant discharged from the evaporator 16 can be guided to the compressor 11 via the receiver 17.

[0044] refer to Figure 1 The refrigerant circulation path 30 may include: a first refrigerant line 31 extending from the outlet of the compressor 11 to the internal condenser 12, a second refrigerant line 32 extending from the internal condenser 12 to the heat exchanger 13, a third refrigerant line 33 extending from the heat exchanger 13 to the external heat exchanger 14, a fourth refrigerant line 34 extending from the external heat exchanger 14 to the cooling-side expansion valve 15, a fifth refrigerant line 35 extending from the cooling-side expansion valve 15 to the evaporator 16, and a sixth refrigerant line 36 extending from the evaporator 16 to the compressor 11.

[0045] The heating-side expansion valve 21 can be located upstream of the first channel 13a of the heat exchanger 13, and downstream of the internal condenser 12. That is, the heating-side expansion valve 21 can be located between the internal condenser 12 and the heat exchanger 13. When the refrigerant subsystem operates in heating mode to heat the passenger compartment, the heating-side expansion valve 21 can regulate the flow of refrigerant and / or the flow rate of refrigerant entering the first channel 13a of the heat exchanger 13, and allow the refrigerant to expand.

[0046] According to an example embodiment, the heating-side expansion valve 21 may be an electronic expansion valve (EXV) with an actuator. The actuator may have a shaft movable to open or close an orifice defined in the valve body of the heating-side expansion valve 21, and the position of this shaft may vary depending on the direction and degree of rotation of the actuator, thus varying the opening degree of the orifice of the heating-side expansion valve 21. A controller may control the operation of the actuator. The heating-side expansion valve 21 may be a fully open EXV. When the refrigerant subsystem is operating in cooling mode, the heating-side expansion valve 21 may be fully open to 100%. When refrigerant passes through the heating-side expansion valve 21 with it fully open to 100%, the refrigerant is not expanded by the heating-side expansion valve 21. When the refrigerant subsystem is operating in heating mode, the heating-side expansion valve 21 may be opened to a set, selected, or predetermined opening degree, allowing the refrigerant to expand through the heating-side expansion valve 21 as it passes through.

[0047] The HVAC housing 20 may have an inlet and an outlet, and the HVAC housing 20 may be configured to allow air to be directed into the vehicle compartment. An evaporator 16 and an internal condenser 12 may be located inside the HVAC housing 20. An electric heater, such as a positive temperature coefficient (PTC) heater, may be positioned downstream or upstream of the internal condenser 12 in the direction of airflow.

[0048] An HVAC system according to an exemplary embodiment of the present invention may include a distribution line 38 fluidly connected to a refrigerant circulation path 30, and the distribution line 38 may connect an upstream point of a cooling-side expansion valve 15 and an upstream point of a compressor 11. The inlet of the distribution line 38 may connect to a connection point 34a of a fourth refrigerant line 34 upstream of the cooling-side expansion valve 15, and the outlet of the distribution line 38 may connect to a first connection point 36a of a sixth refrigerant line 36 upstream of the compressor 11. The distribution line 38 may be configured to allow at least a portion of the refrigerant discharged from the external heat exchanger 14 to bypass the cooling-side expansion valve 15 and the evaporator 16.

[0049] An HVAC system according to an exemplary embodiment of the present invention may include a battery cooler 18, which is thermally connected to a distribution line 38 of a refrigerant circulation path 30 and a battery coolant circulation path 61 of a battery coolant system 60. The battery cooler 18 may be configured to transfer heat between the battery coolant circulating in the battery coolant system 60 and the refrigerant circulating in the refrigerant circulation path 30.

[0050] According to an example embodiment, the battery coolant system 60 may include: a battery coolant circulation path 61 through which battery coolant circulates, a battery 62 fluidly connected to the battery coolant circulation path 61, a battery pump 63 forcing battery coolant circulation, and a battery radiator 64 fluidly connected to the battery coolant circulation path 61. The battery radiator 64 may be positioned adjacent to the front grille of the vehicle, and the battery coolant passing through the battery radiator 64 may be cooled by ambient air forced in by a cooling fan. The battery 62 may have coolant passages disposed inside or outside it, and battery coolant may pass through these coolant passages. The coolant passages of the battery 62 may be fluidly connected to the battery coolant circulation path 61.

[0051] The battery cooler 18 may be fluidly connected to the distribution line 38, and the battery cooler 18 may be configured to transfer heat between the refrigerant passing through the distribution line 38 and the battery coolant passing through the battery coolant circulation path 61 of the battery coolant system 60. The battery cooler 18 may include a first channel 18a fluidly connected to the distribution line 38 of the refrigerant circulation path 30, and a second channel 18b fluidly connected to the battery coolant circulation path 61 of the battery coolant system 60. The refrigerant passing through the first channel 18a may absorb heat from the battery coolant passing through the second channel 18b, thus the refrigerant may be evaporated and the battery coolant may be cooled.

[0052] A cooler-side expansion valve 22 may be located upstream of the battery cooler 18. The cooler-side expansion valve 22 can regulate the flow of refrigerant and / or the flow rate of refrigerant entering the battery cooler 18, and can be configured to cause the refrigerant received from the external heat exchanger 14 to expand. According to an example embodiment, the cooler-side expansion valve 22 may be an electronic expansion valve (EXV) with an actuator. The actuator may have a shaft movable to open or close an orifice defined in the valve body of the cooler-side expansion valve 22, and the position of the shaft may vary depending on the direction and degree of rotation of the actuator, thus varying the opening degree of the orifice of the cooler-side expansion valve 22. A controller may control the operation of the actuator. The cooler-side expansion valve 22 may be a fully open EXV. As the opening degree of the cooler-side expansion valve 22 changes, the flow rate of refrigerant entering the first channel 18a of the battery cooler 18 may change. When adjusting the opening of the cooling-side expansion valve 15 and the cooler-side expansion valve 22, the refrigerant can be distributed to the evaporator 16 and the battery cooler 18 in a set, selected, or predetermined ratio.

[0053] An HVAC system according to an exemplary embodiment of the present invention may include a first bypass line 41 connecting a downstream point of a first channel 13a of a heat exchanger 13 and an upstream point of a compressor 11. The inlet of the first bypass line 41 may be fluidly connected to a third refrigerant line 33 upstream of an external heat exchanger 14, and the outlet of the first bypass line 41 may be fluidly connected to a second connection point 36b of a sixth refrigerant line 36 downstream of an evaporator 16. The first bypass line 41 may connect the point between the external heat exchanger 14 and the heat exchanger 13 to the point between the evaporator 16 and the compressor 11.

[0054] The first bypass line 41 can be configured to allow at least a portion of the refrigerant discharged from the first channel 13a of the heat exchanger 13 to be guided from an upstream point of the external heat exchanger 14 to an upstream point of the compressor 11. The refrigerant passing through the first bypass line 41 can bypass the external heat exchanger 14 and be guided to the compressor 11 via the receiver 17. That is, the first bypass line 41 can be configured to allow at least a portion of the refrigerant discharged from the heat exchanger 13 to bypass the external heat exchanger 14. Therefore, when the HVAC system is operating in heating mode, at least a portion of the refrigerant discharged from the first channel 13a of the heat exchanger 13 can be guided to the compressor 11 via the first bypass line 41.

[0055] An HVAC system according to an exemplary embodiment of the present invention may include a control valve 25 located between a heat exchanger 13, an external heat exchanger 14, and a first bypass line 41. The control valve 25 may be configured to control the flow of refrigerant (direction of refrigerant, flow rate of refrigerant, etc.) between a first passage 13a of the heat exchanger 13, the external heat exchanger 14, and the compressor 11. Specifically, the control valve 25 may be configured to control the flow of refrigerant in such a way that refrigerant discharged from the first passage 13a of the heat exchanger 13 can be directed to at least one of the external heat exchanger 14 and the compressor 11.

[0056] The control valve 25 may include an inlet 25a communicating with a first channel 13a of the heat exchanger 13, a first outlet 25b communicating with an external heat exchanger 14, and a second outlet 25c communicating with a first bypass line 41. The control valve 25 may be switched under the control of a controller so that the inlet 25a can be fluidly connected to at least one of the first outlet 25b and the second outlet 25c.

[0057] According to an example embodiment, when the HVAC system is operating in cooling mode, control valve 25 can be switched under the control of the controller to connect inlet 25a to the first outlet 25b, and refrigerant discharged from the first channel 13a of heat exchanger 13 can be guided to the external heat exchanger 14. When the HVAC system is operating in heating mode, control valve 25 can be switched under the control of the controller to connect inlet 25a to the second outlet 25c, and refrigerant discharged from the first channel 13a of heat exchanger 13 can be guided to compressor 11 through the first bypass line 41.

[0058] The HVAC system according to an exemplary embodiment of the present invention may further include a second bypass line 42, configured such that at least a portion of the refrigerant discharged from the internal condenser 12 can be guided from an upstream point of the heating-side expansion valve 21 to an upstream point of the evaporator 16. The inlet of the second bypass line 42 may be fluidly connected to a connection point 32a of the second refrigerant line 32 upstream of the heating-side expansion valve 21, and the outlet of the second bypass line 42 may be fluidly connected to a connection point 35a of the fifth refrigerant line 35 upstream of the evaporator 16. The second bypass line 42 may connect the point between the internal condenser 12 and the heat exchanger 13 to the point between the cooling-side expansion valve 15 and the evaporator 16. Therefore, refrigerant passing through the second bypass line 42 can bypass the heating-side expansion valve 21 and the heat exchanger 13 and be guided to the evaporator 16. That is, the second bypass line 42 may be configured such that at least a portion of the refrigerant discharged from the internal condenser 12 bypasses the heating-side expansion valve 21 and the heat exchanger 13. When the HVAC system is operating in heating mode, at least a portion of the refrigerant discharged from the internal condenser 12 can be guided to the evaporator 16 through the second bypass line 42.

[0059] An HVAC system according to an exemplary embodiment of the present invention may include an auxiliary expansion valve 23 disposed on a second bypass line 42. The auxiliary expansion valve 23 may be disposed upstream of the evaporator 16 on the second bypass line 42. The auxiliary expansion valve 23 may regulate the flow of refrigerant and / or the flow rate of refrigerant into the evaporator 16, and the auxiliary expansion valve 23 may be configured to cause the refrigerant guided to the evaporator 16 to expand.

[0060] According to an example embodiment, the auxiliary expansion valve 23 may be an electronic expansion valve (EXV) with an actuator. The actuator may have a shaft movable to open or close an orifice defined in the valve body of the auxiliary expansion valve 23, and the position of this shaft may vary depending on the direction and degree of rotation of the actuator, thus varying the opening degree of the orifice of the auxiliary expansion valve 23. A controller may control the operation of the actuator. As the opening degree of the auxiliary expansion valve 23 changes, the flow rate of refrigerant entering the evaporator 16 may vary. The auxiliary expansion valve 23 may be a fully open EXV. When the HVAC system is operating in heating and back-blowing modes, the auxiliary expansion valve 23 may be fully open to 100%. When the refrigerant passes through the auxiliary expansion valve 23 with it fully open to 100%, the refrigerant is not expanded by the auxiliary expansion valve 23. When the HVAC system is operating in cooling mode, the auxiliary expansion valve 23 may be completely closed.

[0061] An HVAC system according to an exemplary embodiment of the present invention may include a regulating valve 70 disposed between an evaporator 16 and a compressor 11. The regulating valve 70 may be disposed downstream of the evaporator 16 and configured to regulate the flow rate of refrigerant flowing from the evaporator 16 into the compressor 11. The regulating valve 70 may be disposed upstream of a first connection point 36a of a sixth refrigerant line 36, and a distribution line 38 may be connected to the first connection point 36a of the sixth refrigerant line 36, such that refrigerant discharged from the first passage 18a of the battery cooler 18 and refrigerant discharged from the evaporator 16 may converge at the first connection point 36a of the sixth refrigerant line 36.

[0062] The regulating valve 70 can be configured to regulate the flow rate of refrigerant discharged from the evaporator 16 by adjusting the opening of an orifice defined in its valve body. Specifically, when the HVAC system is operating in heating mode, the opening of the regulating valve 70 can be adjusted, thereby regulating the flow rate of refrigerant discharged from the evaporator 16. When the HVAC system is operating in cooling mode, the regulating valve 70 can be fully opened to 100%.

[0063] The controller can be configured to control the corresponding operations of the compressor 11, cooling-side expansion valve 15, heating-side expansion valve 21, cooler-side expansion valve 22, auxiliary expansion valve 23, regulating valve 70, etc., so the overall operation of the HVAC system can be controlled by the controller.

[0064] Figure 2 This illustrates the refrigerant flow when the HVAC system according to an exemplary embodiment of the present invention is operating in heating mode. (Reference) Figure 2When compressor 11 operates at a set, selected, or predetermined RPM, compressor 11 can compress refrigerant, and the refrigerant discharged from the outlet of compressor 11 can be in a high-temperature, high-pressure state. The refrigerant compressed by compressor 11 can be directed to internal condenser 12, and internal condenser 12 can be cooled by air passing through HVAC housing 20, so that the refrigerant passing through internal condenser 12 can be condensed by the air, and the air is heated.

[0065] Refrigerant discharged from the internal condenser 12 can be directed to the heating-side expansion valve 21. When the HVAC system is operating in heating mode, the heating-side expansion valve 21 can open to a set, selected, or predetermined opening degree, allowing the refrigerant passing through the heating-side expansion valve 21 to expand. The expanded refrigerant can then pass through the first channel 13a of the heat exchanger 13. The refrigerant passing through the first channel 13a of the heat exchanger 13 can absorb heat from the coolant passing through the second channel 13b of the heat exchanger 13, thus allowing the refrigerant to evaporate within the heat exchanger 13.

[0066] When the HVAC system is operating in heating mode, the control valve 25 can be switched under the control of the controller so that the inlet 25a can be fluidly connected to the second outlet 25c, so that the refrigerant discharged from the first channel 13a of the heat exchanger 13 can be guided to the compressor 11 through the first bypass line 41.

[0067] When the HVAC system is operating in heating mode, the auxiliary expansion valve 23 can be fully opened, and at least a portion of the refrigerant discharged from the internal condenser 12 can pass through the auxiliary expansion valve 23. The refrigerant passing through the fully open auxiliary expansion valve 23 does not expand within it. The refrigerant discharged from the auxiliary expansion valve 23 can pass through the evaporator 16. When the regulating valve 70 is opened to a set, selected, or predetermined opening degree, the flow rate of the refrigerant discharged from the evaporator 16 can be regulated, and the refrigerant discharged from the regulating valve 70 and the refrigerant discharged from the second outlet 25c of the control valve 25 can merge at the second connection point 36b of the sixth refrigerant line 36, and then be guided to the compressor 11 through the receiver 17.

[0068] In existing HVAC systems, when the system operates in heating mode at relatively low ambient temperatures, the refrigerant may not be able to fully absorb heat from the PE coolant. Because the refrigerant does not evaporate sufficiently in the heat exchanger, the compressor suction pressure may drop to the threshold pressure (e.g., 0.2 kgf / cm²). 2When the compressor's suction pressure falls below the threshold pressure, the compressor's efficiency may decrease, causing the compressor's RPM to drop below the threshold RPM, or the compressor to stop due to low-pressure protection. Consequently, the refrigerant flow rate decreases relatively, and the temperature of the refrigerant discharged from the compressor decreases relatively, potentially degrading the HVAC system's coefficient of performance (COP).

[0069] According to an exemplary embodiment of the present invention, when the HVAC system is operating in heating mode, the auxiliary expansion valve 23 can be fully opened, and the pressure and temperature of the refrigerant discharged from the evaporator 16 can be higher than the pressure and temperature of the refrigerant discharged from the first channel 13a of the heat exchanger 13. After the refrigerant discharged from the evaporator 16 and the refrigerant discharged from the first channel 13a of the heat exchanger 13 merge, the refrigerant can be directed to the compressor 11, so that the suction pressure of the compressor 11 can be maintained above the threshold pressure. Since the suction pressure of the compressor 11 can be relatively high, the RPM of the compressor 11 can be appropriately controlled to meet the target heating temperature of the cabin set by the user, thus improving the heating performance of the HVAC system by using refrigerant.

[0070] Figure 3 This illustrates the refrigerant flow when the HVAC system according to an exemplary embodiment of the present invention is operating in cooling mode. (Reference) Figure 3 When compressor 11 operates at a set, selected, or predetermined RPM, compressor 11 can compress refrigerant, and the refrigerant discharged from the outlet of compressor 11 can be in a high-temperature, high-pressure state. The refrigerant compressed by compressor 11 can pass through internal condenser 12.

[0071] When the HVAC system is operating in cooling mode, the heating-side expansion valve 21 can be fully opened, preventing the refrigerant passing through it from expanding, and allowing the refrigerant discharged from the heating-side expansion valve 21 to be guided to the first channel 13a of the heat exchanger 13. The refrigerant passing through the first channel 13a of the heat exchanger 13 can exchange heat with the coolant passing through the second channel 13b of the heat exchanger 13.

[0072] When the HVAC system is operating in cooling mode, control valve 25 can be switched under the control of the controller to allow inlet 25a to be fluidly connected to the first outlet 25b. Therefore, refrigerant discharged from the first channel 13a of heat exchanger 13 can be directed to the external heat exchanger 14 instead of the first bypass line 41. Refrigerant discharged from the external heat exchanger 14 can be directed to the cooling-side expansion valve 15. When the cooling-side expansion valve 15 opens to a set, selected, or predetermined opening, the refrigerant can expand through the cooling-side expansion valve 15. Refrigerant discharged from the cooling-side expansion valve 15 can pass through the evaporator 16, and refrigerant discharged from the evaporator 16 can be directed to the compressor 11 through the receiver 17.

[0073] When the HVAC system is running in cooling mode, regulating valve 70 can be fully opened.

[0074] When the cooler-side expansion valve 22 opens to a set, selected, or predetermined opening degree, a portion of the refrigerant discharged from the external heat exchanger 14 can pass through the cooler-side expansion valve 22 and expand. The refrigerant passing through the first channel 18a of the battery cooler 18 can absorb heat from the battery coolant passing through the second channel 18b, thus allowing the refrigerant to evaporate and the battery coolant to be cooled. The refrigerant discharged from the first channel 18a of the battery cooler 18 can be guided to the compressor 11 through the receiver 17.

[0075] Figure 4 The diagram illustrates the refrigerant flow when the HVAC system according to an exemplary embodiment of the invention is operating in back-blowing mode. In back-blowing mode, when the HVAC system is not operating in cooling mode, the blower of the HVAC housing 20 can run for a set, selected, or predetermined period of time, such that the evaporator 16 of the HVAC housing 20 can be dried by the air blown by the blower.

[0076] refer to Figure 4 When the HVAC system operates in back-blowing mode, the auxiliary expansion valve 23 can be fully opened, allowing the refrigerant discharged from the internal condenser 12 to pass through the evaporator 16, and the evaporator 16 can be quickly dried by the refrigerant discharged from the internal condenser 12. Therefore, the operating time of the HVAC system in back-blowing mode can be significantly reduced.

[0077] As described above, the HVAC system according to an exemplary embodiment of the present invention can be designed to improve heating performance by utilizing refrigerant circulation when the HVAC system operates in heating mode under relatively low ambient temperature conditions, by preventing the compressor suction pressure from dropping below a threshold pressure. By minimizing the use of electric heaters, embodiments of the present invention can reduce energy waste and improve the electrical efficiency of electric vehicles.

[0078] According to an exemplary embodiment of the present invention, when the HVAC system is operating in heating mode, the auxiliary expansion valve can be fully opened, and the pressure and temperature of the refrigerant discharged from the evaporator can be higher than the pressure and temperature of the refrigerant discharged from the first channel of the heat exchanger. After the refrigerant discharged from the evaporator and the refrigerant discharged from the first channel of the heat exchanger merge, the refrigerant can be directed to the compressor, so that the compressor's suction pressure can be maintained above a threshold pressure. Because the compressor's suction pressure is relatively high, the compressor's RPM can be appropriately controlled to meet the user-set target heating temperature of the vehicle compartment, thus the heating performance of the HVAC system can be improved using the refrigerant of the embodiments of the present invention.

[0079] Several embodiments have been disclosed herein. It will be understood that various features of different embodiments can be combined.

[0080] Although the present invention has been described above with reference to exemplary embodiments and accompanying drawings, the present invention is not necessarily limited thereto. Various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the invention as claimed in the appended claims, or equivalent solutions can be adopted.

Claims

1. A vehicle heating, ventilation, and air conditioning system, comprising: compressor; An internal condenser is located downstream of the compressor; A heat exchanger is disposed downstream of the internal condenser, wherein the heat exchanger is configured to transfer heat between the refrigerant and the coolant circulating in the coolant system; An evaporator is located downstream of the heat exchanger and upstream of the compressor. A first bypass line connects the downstream point of the heat exchanger and the upstream point of the compressor; and The second bypass line connects the downstream point of the internal condenser and the upstream point of the evaporator.

2. The vehicle heating, ventilation, and air conditioning system according to claim 1 further includes an external heat exchanger, wherein the external heat exchanger is disposed between the heat exchanger and the evaporator, wherein, The external heat exchanger is configured to transfer heat between the refrigerant and ambient air, wherein the first bypass line is configured such that at least a portion of the refrigerant discharged from the heat exchanger can be guided from an upstream point of the external heat exchanger to an upstream point of the compressor.

3. The vehicle heating, ventilation and air conditioning system according to claim 2 further includes: A cooling-side expansion valve is disposed between the external heat exchanger and the evaporator; as well as A heating-side expansion valve is disposed between the heat exchanger and the internal condenser, wherein the second bypass line is configured such that at least a portion of the refrigerant discharged from the internal condenser can be guided from an upstream point of the heating-side expansion valve to an upstream point of the evaporator.

4. The vehicle heating, ventilation and air conditioning system of claim 2, further comprising a control valve configured to control the flow of refrigerant in such a way that refrigerant discharged from the heat exchanger can be directed to at least one of the external heat exchanger and the compressor.

5. The vehicle heating, ventilation, and air conditioning system according to claim 4, wherein, The control valve includes: An inlet connected to the heat exchanger; The first outlet connected to the external heat exchanger; and A second outlet connected to the first bypass pipeline.

6. The vehicle heating, ventilation, and air conditioning system according to claim 5, wherein, The control valve is configured to be switched so that the inlet can be fluidly connected to at least one of the first outlet and the second outlet.

7. The vehicle heating, ventilation, and air conditioning system according to claim 5, wherein, The control valve is configured to be switched based on the vehicle's HVAC system operating in heating mode so that the inlet can be fluidly connected to the second outlet.

8. The vehicle heating, ventilation, and air conditioning system according to claim 1 further includes an auxiliary expansion valve disposed on the second bypass pipeline, wherein, The auxiliary expansion valve is located on the upstream side of the evaporator on the second bypass pipeline.

9. The vehicle heating, ventilation, and air conditioning system according to claim 8, wherein, The auxiliary expansion valve is configured to be fully opened based on the vehicle's HVAC system operating in heating mode.

10. The vehicle heating, ventilation, and air conditioning system according to claim 1, further comprising a regulating valve disposed between the evaporator and the compressor, wherein, The regulating valve is configured to adjust its opening degree to regulate the flow rate of refrigerant discharged from the evaporator.

11. The vehicle heating, ventilation, and air conditioning system according to claim 1, wherein, The coolant system is a power electronic coolant system, and the heat exchanger includes: The first channel through which the refrigerant passes; and The coolant passes through a second channel, wherein the second channel of the heat exchanger is fluidly connected to the power electronic coolant system.

12. A vehicle heating, ventilation, and air conditioning system, comprising: Power electronics cooling system; compressor; An internal condenser is located downstream of the compressor; Evaporator; A power electronic heat exchanger is thermally connected to the power electronic cooling system, wherein the power electronic heat exchanger is located downstream of the internal condenser; An external heat exchanger, wherein the external heat exchanger is located downstream of the power electronic heat exchanger, and wherein the external heat exchanger is located upstream of the evaporator; A cooling-side expansion valve is disposed between the external heat exchanger and the evaporator; A refrigerant circulation line configured to allow refrigerant to flow through the vehicle's heating, ventilation, and air conditioning system, wherein the refrigerant circulation line includes: The first refrigerant line extends from the outlet of the compressor to the internal condenser. A second refrigerant line extends from the internal condenser to the power electronic heat exchanger. A third refrigerant line extends from the power electronic heat exchanger to the external heat exchanger. The fourth refrigerant line extends from the external heat exchanger to the cooling-side expansion valve. The fifth refrigerant line extends from the cooling-side expansion valve to the evaporator. The sixth refrigerant line extends from the evaporator to the inlet of the compressor. The seventh refrigerant line extends through the power electronic heat exchanger, and The first bypass refrigerant line has its first end connected to the first connection point on the sixth refrigerant line; A control valve is located between the power electronic heat exchanger, the external heat exchanger, and the first bypass refrigerant line, wherein the control valve is connected to a second end of the first bypass refrigerant line, wherein a third refrigerant line extends from the control valve to the external heat exchanger, and wherein the control valve is configured to control the flow of refrigerant discharged from the seventh refrigerant line of the power electronic heat exchanger to achieve at least one of the following: guiding refrigerant to the external heat exchanger via the third refrigerant line; or guiding refrigerant to the compressor via the sixth refrigerant line.

13. The vehicle heating, ventilation, and air conditioning system according to claim 12, wherein, The refrigerant circulation line further includes a second bypass refrigerant line, the first end of which is connected to a second connection point on the second refrigerant line between the internal condenser and the power electronic heat exchanger, and wherein the second end of the second bypass refrigerant line is connected to a third connection point on the fifth refrigerant line between the cooling-side expansion valve and the evaporator.

14. The vehicle heating, ventilation, and air conditioning system according to claim 13, further comprising an auxiliary expansion valve located on the second bypass refrigerant line, wherein, The auxiliary expansion valve is configured to regulate the flow of refrigerant into the evaporator via the third connection point on the fifth refrigerant line and from the internal condenser via the second connection point on the second refrigerant line.

15. The vehicle heating, ventilation and air conditioning system according to claim 12, further comprising a heating-side expansion valve, the heating-side expansion valve being located on the second refrigerant line between the internal condenser and the power electronic heat exchanger.

16. The vehicle HVAC system according to claim 12, further comprising an HVAC housing, wherein, The internal condenser is at least partially located within the HVAC housing, and the evaporator is at least partially located within the HVAC housing.

17. The vehicle HVAC system according to claim 12, further comprising a battery cooler, wherein, The refrigerant circulation line also includes a refrigerant distribution line, which is connected to the fourth refrigerant line between the external heat exchanger and the cooling-side expansion valve, and to the sixth refrigerant line, and extends through the battery cooler.

18. A vehicle heating, ventilation, and air conditioning system, comprising: Power electronics cooling system; compressor; An internal condenser is located downstream of the compressor; Evaporator; A power electronic heat exchanger is thermally connected to the power electronic cooling system, wherein the power electronic heat exchanger is located downstream of the internal condenser; An external heat exchanger, wherein the external heat exchanger is located downstream of the power electronic heat exchanger, and wherein the external heat exchanger is located upstream of the evaporator; A cooling-side expansion valve is disposed between the external heat exchanger and the evaporator; A refrigerant circulation line configured to allow refrigerant to flow through the vehicle's heating, ventilation, and air conditioning system, wherein the refrigerant circulation line includes: The first refrigerant line extends from the outlet of the compressor to the internal condenser. A second refrigerant line extends from the internal condenser to the power electronic heat exchanger. A third refrigerant line extends from the power electronic heat exchanger to the external heat exchanger. The fourth refrigerant line extends from the external heat exchanger to the cooling-side expansion valve. The fifth refrigerant line extends from the cooling-side expansion valve to the evaporator. The sixth refrigerant line extends from the evaporator to the inlet of the compressor. The seventh refrigerant line extends through the power electronic heat exchanger. The first bypass refrigerant line has its first end connected to the first connection point on the sixth refrigerant line, and A second bypass refrigerant line has its first end connected to a second connection point on the second refrigerant line between the internal condenser and the power electronic heat exchanger, and its second end connected to a third connection point on the fifth refrigerant line between the cooling-side expansion valve and the evaporator; and A control valve is located between the power electronic heat exchanger, the external heat exchanger, and the first bypass refrigerant line, wherein the control valve is connected to a second end of the first bypass refrigerant line, wherein a third refrigerant line extends from the control valve to the external heat exchanger, and wherein the control valve is configured to control the flow of refrigerant discharged from the seventh refrigerant line of the power electronic heat exchanger to achieve at least one of the following: guiding refrigerant to the external heat exchanger via the third refrigerant line; or guiding refrigerant to the compressor via the sixth refrigerant line.

19. The vehicle heating, ventilation, and air conditioning system according to claim 18, further comprising an auxiliary expansion valve located on the second bypass refrigerant line, wherein, The auxiliary expansion valve is configured to regulate the flow of refrigerant into the evaporator via the third connection point on the fifth refrigerant line and from the internal condenser via the second connection point on the second refrigerant line.

20. The vehicle heating, ventilation and air conditioning system according to claim 19 further includes a heating-side expansion valve, the heating-side expansion valve being located on the second refrigerant pipeline between the second connection point on the second refrigerant pipeline and the power electronic heat exchanger.

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