Heat pump system with multi-way position valve

Abstract

The present disclosure provides "Heat pump system with multi-pass position valve". A vehicle heat pump system is provided that includes a thermal loop, an eight-way valve, and a controller. The thermal loop includes a compressor, a first portion, and a second portion. The first portion includes an exterior heat exchanger. The second portion includes a cabin heat exchanger. The eight-way valve is downstream of the compressor and has a first position in which refrigerant flows within the portion in a cooling mode and a second position in which refrigerant flows within the portion in a heating mode. The controller switches the eight-way valve between the first position and the second position. The exterior heat exchanger operates as a condenser in the cooling mode and the eight-way valve directs refrigerant flow from the exterior heat exchanger to the cabin heat exchanger.

Description

Technical Field

[0001] This disclosure relates to a heat pump system for helping to manage the thermal condition of a vehicle. Background Technology

[0002] Air-to-air heat pump systems may require complex control systems, incur high costs due to the need for additional hardware, and may operate under charge imbalance conditions in cooling and heating modes due to the different sizes of indoor and outdoor condensers. Summary of the Invention

[0003] The vehicle heat pump system includes a thermal loop, an eight-way valve, and a controller. The thermal loop includes a compressor, a first section, and a second section. The first section includes an external heat exchanger. The second section includes a passenger compartment heat exchanger. The eight-way valve is located downstream of the compressor and has a first position and a second position. In the first position, refrigerant flows within the section in a cooling mode, while in the second position, refrigerant flows within the section in a heating mode. The controller switches the eight-way valve between the first and second positions. The external heat exchanger operates as a condenser in the cooling mode, and the eight-way valve directs the refrigerant flow from the external heat exchanger to the passenger compartment heat exchanger. In the heating mode, the external heat exchanger operates as an evaporator, and the eight-way valve directs the refrigerant flow from the passenger compartment heat exchanger to the external heat exchanger. The system may also include an air-side heater. The system may further include an air-side heater that, when a sensor detects a temperature below a predetermined threshold, supplements heat in heating mode to deliver to the passenger compartment, or reheats dehumidified air to a predetermined temperature in dehumidification and reheating mode. The system may also include a mixing gate to control the temperature of the air supplied to the passenger compartment. The section may further include: an expansion device for reducing the pressure of the refrigerant flow; an internal heat exchanger located upstream of the expansion device; a flash tank located downstream of the expansion device to separate the vapor-liquid mixture; and a control valve located downstream of the flash tank to balance the pressure of the refrigerant flowing from the flash tank and the eight-way valve. The eight-way valve may include a valve cover having eight ports. The eight-way valve may be arranged with the first and second sections to influence the refrigerant's phase transition state, wherein components of the sections are arranged relative to each other to influence the refrigerant's phase transition state, wherein the refrigerant is in liquid or liquid-vapor mixture form when flowing to the passenger compartment heat exchanger in cooling mode, and in vapor form when flowing to the passenger compartment heat exchanger in heating mode. The refrigerant may be one of R134a, R1234yf, R152a, R410A, hydrocarbons, ammonia, and R744. The second part of the thermal loop may also include a flash tank arranged with an eight-way valve to substantially remove vapor from the refrigerant, such that the refrigerant is substantially entirely liquid when entering a compartment heat exchanger in cooling mode or an external heat exchanger in heating mode. The thermal loop may include only two heat exchangers and only one expansion device.

[0004] A vehicle heat pump system includes a compressor configured to increase refrigerant pressure through an external heat exchanger in a cooling mode, defining a first position of a multi-position valve, and to increase refrigerant pressure through a passenger compartment heat exchanger in a heating mode, defining a second position of the multi-position valve. The compressor and multi-position valve are arranged such that the refrigerant pressure is substantially the same in both cooling and heating modes. The system may include an expansion device, a flash tank, and control valves arranged relative to each other to balance the pressure of refrigerant flowing into and out of the heat exchangers. The system may include a sensor, a controller, and an air-side heater in fluid communication with the passenger compartment heat exchanger. The controller may be programmed to activate the air-side heater to provide supplemental heat to the passenger compartment in response to the sensor detecting a temperature below a predetermined threshold. The refrigerant associated with the refrigerant pressure may be one of R134a, R1234yf, R152a, R410A, hydrocarbons, ammonia, and R744. The flash tank may be arranged with the multi-position valve such that the refrigerant is substantially entirely liquid when entering the passenger compartment heat exchanger in cooling mode. The system may include only two heat exchangers and only one expansion device.

[0005] The vehicle heat pump system includes a pair of conduit sections of a heat loop and components in fluid communication with each other, including only one internal heat exchanger, a compressor, an external heat exchanger, a passenger compartment heat exchanger, only one expansion device, a flash tank, only one control valve, and an eight-way valve arranged within the pair of conduit sections to switch between a first position in cooling mode and a second position in heating mode. Refrigerant flows directly from the external heat exchanger to the internal heat exchanger in cooling mode, and refrigerant flowing out of the external heat exchanger in heating mode is pressure-balanced via the only control valve leading to the internal heat exchanger in heating mode. Refrigerant can flow directly from the compressor to the external heat exchanger in cooling mode, and refrigerant can flow directly from the compressor to the passenger compartment heat exchanger in heating mode. The system may also include an air-side heater. When the passenger compartment heat exchanger operates as a condenser, the air-side heater can supplement the heat distribution to the passenger compartment in heating mode, or when the passenger compartment heat exchanger operates as an evaporator, it can reheat dehumidified air to a predetermined temperature in dehumidification and reheating mode. The external heat exchanger can operate as a condenser in cooling mode and as an evaporator in heating mode. The flash tank can be arranged with an eight-way valve such that the refrigerant flowing to the compartment heat exchanger in cooling mode or to the external heat exchanger in heating mode is essentially a liquid. The eight-way valve can include a valve housing with eight ports, a first pair of which can be located on a first side of the valve housing, opposite a second pair of eight ports located on a second side of the valve housing. Four of the eight ports are located on a third side of the valve housing. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of an example of an electrified vehicle.

[0007] Figure 2 This is a schematic diagram of a vehicle's heat pump system.

[0008] Figure 3 yes Figure 2 A perspective view of an example of an eight-way two-position valve for a vehicle heat pump system.

[0009] Figure 4 yes Figure 2 A schematic diagram of a vehicle heat pump system operating in the first mode is shown.

[0010] Figure 5 yes Figure 2 A schematic diagram of a vehicle heat pump system operating in the second mode is shown.

[0011] Figure 6 yes Figure 2 A schematic diagram of a vehicle heat pump system operating in the third mode is shown.

[0012] Figure 7 This is a graph illustrating an example of the pressure-enthalpy relationship in a vehicle heat pump system. Detailed Implementation

[0013] This document describes embodiments of the present disclosure. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various forms and alternatives. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art to employ embodiments of the present disclosure in different ways. As will be understood by those skilled in the art, various features shown and described with reference to any of the drawings may be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of this disclosure may be desired for particular applications or implementations.

[0014] In certain situations, electrified vehicles such as BEVs and PHEVs may require alternative heat sources to replace or increase the amount of heat discharged by a conventional internal combustion engine to meet cabin heating targets. Vapor compression heat pump (VCHP) technology can provide cabin heating by extracting energy from the vehicle's surrounding environment. Compared to other thermal systems that use high-voltage positive temperature coefficient (HV-PTC) heaters or phase change materials (PCMs) for heat storage, heat pump systems can extend the driving range by up to 30%.

[0015] Figure 1 This is a schematic diagram of an example of an electrified vehicle 10. The vehicle 10 may include one or more power sources 12, which may be used to propel the vehicle 10 and / or power vehicle components. The vehicle 10 may include a passenger compartment 20, an engine compartment 22, and a heat pump system 24. The heat pump system 24 may include a coolant subsystem 30, a refrigerant subsystem 32, and a ventilation subsystem 34.

[0016] The coolant subsystem 30 can circulate a fluid, such as coolant, to cool the power source 12. The coolant subsystem 30 may include a coolant pump 40, an intermediate heat exchanger 42, a heater core 44, and a bypass loop 48, which are fluidly interconnected via conduits. The coolant subsystem 30 may include a secondary heat source 49. The secondary heat source 49 may be, for example, a positive temperature coefficient (PTC) heater. In vehicle embodiments including an engine, the engine may also operate as a secondary heat source.

[0017] The refrigerant subsystem 32 may include a compressor 60, a first control valve 62, a first expansion device 64, an external heat exchanger 66, a second control valve 68, a third control valve 70, an accumulator 72, a second expansion device 74, an internal heat exchanger 76, and an optional internal heat exchanger 78. The components of the heat pump subsystem 32 may be fluidly connected in a closed loop via one or more conduits.

[0018] Compared to conventional air conditioning and heating systems, Figure 1 The heat pump system includes at least one or more heat exchangers (e.g., intermediate heat exchanger 42), an expansion device (e.g., expansion device 64), and multiple control valves (e.g., valves 62, 68, 70). The added hardware increases system cost and control complexity.

[0019] Figure 2 This is a schematic diagram of a vehicle heat pump system including an eight-way dual-position valve, typically referred to as heat pump system 120. The thermal loop of heat pump system 120 includes components that help manage the vehicle's thermal condition. Heat pump system 120 may include a heat exchanger 124, at least one compressor 126, an eight-way valve 130, an external heat exchanger 134, a passenger compartment heat exchanger 142, and an expansion device 136. Compressor 126 may be powered by an electric or non-electric power source and operates before the refrigerant enters the eight-way dual-position valve (eight-way valve 130) to compress the refrigerant from a low-pressure state to a high-pressure state.

[0020] Figure 3 A detailed view of an example of the structure of an eight-way valve 130 is shown. Figure 3Two of the ports 131 of the eight-way valve 130 are not visible but are shown in dashed lines. Various configurations can be used to orient the eight-way valve 130 within a heat pump system such as heat pump system 120. For example, the ports 131 of the eight-way valve 130 can be configured to guide fluid between each of the eight ports 131. The values ​​for the low-pressure and high-pressure states will vary based on the refrigerant type, components of heat pump system 120, and passenger-selected inputs. The external heat exchanger 134 functions as a condenser in cooling mode to dissipate heat to the surrounding air and as an evaporator in heating mode to absorb heat from the surrounding air. Before supplying the incoming airflow to the compartment, the compartment heat exchanger 142 functions as an evaporator in cooling mode to cool the incoming airflow and as a condenser in heating mode to heat the incoming airflow. The expansion device 136 can be a fixed orifice tube (FOT), a thermal expansion device (TXV), or an electronic expansion device (EXV).

[0021] The heat pump system 120 may further include: a flash tank 138 for separating the vapor-liquid mixture after the expansion device 136 and supplying liquid refrigerant to the compartment heat exchanger 142; an air-side heater 144 as a supplementary heat source; a temperature mixing gate 145; a control valve 143 for allowing vapor refrigerant to combine with outlet refrigerant from the evaporator; and a heat exchanger 124 for improving system efficiency.

[0022] While various types of refrigerants can be used with the heat pump system 120, non-limiting examples of refrigerants include R134a, R1234yf, R410A, hydrocarbons, ammonia, R744, and R152a.

[0023] Compared with previous thermal system architectures (such as Figure 1 Compared to the architecture described above, the heat pump system 120 improves energy efficiency, simplifies control logic, and reduces costs by eliminating several components. Furthermore, there is no refrigerant charge imbalance problem because the system volume remains substantially the same in cooling and heating modes. Additionally, the heat pump system 120 may include only two heat exchangers and only one expansion device.

[0024] Figure 4An example of operation of the heat pump system 120 in cooling mode is shown. When the heat pump system 120 operates in cooling mode, the eight-way valve 130 can be in a first position and direct refrigerant to the external heat exchanger 134 for thermal communication with the surrounding air. The first heating section 121 and the second heating section 123 operate together with the components of the heat pump system 120 to manage the vehicle's thermal condition. In cooling mode, the first heating section 121 can be a high-pressure section, while the second heating section 123 can be a low-pressure section. Refrigerant can flow through the first heating section 121 and the second heating section 123. In cooling mode, the external heat exchanger 134 can operate as a condenser to move heat to the outside of the vehicle. The refrigerant can then pass through the eight-way valve 130 to the heat exchanger 124. Due to the pressure drop, the expansion device 136 can convert the refrigerant into a mixture of liquid and vapor, which then enters the flash tank 138. The flash tank 138 can separate the liquid and mixture portions from each other and direct the liquid portion to the cabin heat exchanger 142 via the eight-way valve 130. The control valve 143 can be operated to allow vaporized refrigerant to bypass and combine with the outlet refrigerant from the evaporator, and to balance the refrigerant pressure.

[0025] Components of the heat pump system 120 can be operated to adjust the temperature of the refrigerant. For example, for R134a refrigerant, the dashed line along the hot section indicates a refrigerant temperature and high-pressure condition of approximately 100°C to 120°C. The solid line along the hot section indicates a refrigerant temperature and low-pressure condition of approximately 1°C to 8°C.

[0026] In cooling mode, the compartment heat exchanger 142 can operate as an evaporator, where liquid refrigerant absorbs heat from the incoming air. Cooled air is then supplied to the compartment. Refrigerant exiting the compartment heat exchanger 142 can flow back to the eight-way valve 130 and combine with a vapor portion of the refrigerant mixture from the flash tank 138. The combined vapor and liquid refrigerant can then pass through the heat exchanger 124 and return to the compressor 126 to complete the cycle.

[0027] By receiving refrigerant in a liquid state, the compartment heat exchanger 142 can be shown to have improved efficiency due to the improved refrigerant distribution in the manifold of the compartment heat exchanger 142 and the reduced pressure drop on the compartment heat exchanger 142.

[0028] Air-side heaters 144, such as PTC heaters, can operate in two main functions. The first function involves providing supplemental heat at low temperatures when the system cannot provide sufficient heat to the passenger compartment. The second function involves the system's dehumidification and reheating modes. Air-side heaters 144 can be operated to warm the air before it is supplied to the passenger compartment. In cooling mode, heaters 144 can be turned off and the mixing door 145 can be closed.

[0029] Figure 5 An example of operation of the heat pump system 120 in heating mode is shown. The compressor 126 can be operated to compress the refrigerant from a low-pressure state to a high-pressure state before the refrigerant enters the eight-way valve 130. When the heat pump system 120 operates in heating mode, the eight-way valve 130 can be in a second position and direct the refrigerant to the passenger compartment heat exchanger 142. The passenger compartment heat exchanger 142 can operate as a condenser, where the high-temperature refrigerant dissipates heat to the incoming air. The heated air is then supplied to the passenger compartment. Cooled refrigerant exiting the passenger compartment heat exchanger 142 can be directed by the eight-way valve 130 to the heat exchanger 124.

[0030] The refrigerant can then pass through expansion device 136 and be expanded into a mixture of vapor and liquid before entering flash tank 138. Flash tank 138 separates the liquid and mixture portions from each other and directs the liquid portion to external heat exchanger 134 via eight-way valve 130. In heating mode, the external heat exchanger can operate as an evaporator to absorb heat from the external environment. The boiling refrigerant exiting external heat exchanger 134 can flow back to eight-way valve 130 and merge with the vapor portion of the mixture from flash tank 138. The combined refrigerant can then pass through heat exchanger 124 and return to compressor 126 to complete the cycle.

[0031] Similarly, by receiving refrigerant in a liquid state, the external heat exchanger 134 can be shown to have improved efficiency due to the improved refrigerant distribution in the manifold of the external heat exchanger 134 and the reduced pressure drop on the external heat exchanger 134.

[0032] In heating mode, if the heat pump system 120 cannot provide sufficient capacity, for example in low ambient conditions, the air-side heater 144 can be turned on as a supplementary heating source.

[0033] Figure 6 An example of operation of the heat pump system 120 in dehumidification and reheating mode is shown. In this mode, the refrigerant circuit can follow a similar pattern to that described in the cooling mode to cool and dehumidify the humid air. The air-side heater 144 can be turned on to heat the dry air to a predetermined comfort temperature before supplying it to the passenger cabin. The state of the mixing door 145 can be adjusted to help achieve the predetermined comfort temperature.

[0034] The heat pump system 120 offers several advantages over previous architectures. For example, compared to previous systems, the heat pump system 120 has a simplified architecture and control logic through the use of an eight-way valve 130. This design eliminates at least one expansion device, one or more flow control valves, and two heat exchangers. System performance is also improved due to increased evaporator efficiency. Furthermore, there is no refrigerant charge imbalance problem because the system volume remains substantially the same in cooling and heating modes.

[0035] Figure 7 This is a graph illustrating an example of a pressure-enthalpy (ph) diagram 160 for a heat pump system 120. The Y-axis 164 represents pressure, while the X-axis 166 represents enthalpy. The portion of diagram 160 below and inside the area defined by line 198 and the X-axis 166 represents the two-phase form of the refrigerant, comprising liquid and vapor.

[0036] At point 200, the refrigerant is in a low-pressure vapor state and enters compressor 126, where it is compressed into a high-temperature, high-pressure vapor, indicated by point 202. The transition from point 200 to point 202 corresponds to the movement of the refrigerant through compressor 126 to eight-way valve 130. During this transition, the pressure of the refrigerant in its vapor form increases. The high-temperature, high-pressure vapor at point 202 is cooled to point 206 in an external heat exchanger 134 in cooling or dehumidification mode, or in a cabin heat exchanger 142 in heating mode, where the refrigerant transitions to a two-phase form and then to a liquid. The transition from point 206 to point 208 corresponds to the movement of the refrigerant through heat exchanger 124, where it is further cooled. The transition from point 208 to point 210 corresponds to the movement of the refrigerant through expansion device 136 to expand the vapor into a low-pressure, vapor-liquid mixture, which is then separated in flash tank 138. In this transition, the refrigerant pressure decreases, and the refrigerant transforms into a two-phase form. The transitions from point 210 to points 212 and 218 correspond to the movement of the refrigerant in flash tank 138, where the vapor-liquid mixture (e.g., the refrigerant at point 210) is separated into a pure liquid at point 212 and into a pure vapor at point 218. The transition from point 212 to point 220 corresponds to the movement of the refrigerant in the evaporator, where the refrigerant absorbs heat. In this example, the evaporator is a cabin heat exchanger 142 in cooling or dehumidification mode and an external heat exchanger 134 in heating mode. Point 218 corresponds to the condition where the refrigerant moves from flash tank 138 to control valve 143. Point 219 corresponds to the merging of the refrigerant with saturated vapor. Point 220 corresponds to the condition where the refrigerant moves from the evaporator to heat exchanger 124.

[0037] While various embodiments have been described above, it is not intended that these embodiments describe all possible forms covered by the claims. The language used in this specification is descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of this disclosure. As previously described, features of the various embodiments may be combined to form further embodiments that may not be explicitly described or illustrated in this disclosure. While various embodiments may have been described as providing advantages or superiority over other embodiments or prior art implementations with respect to one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, merchantability, appearance, consistency, robustness, customer acceptability, reliability, accuracy, etc. Therefore, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are also within the scope of this disclosure and may be desirable for a particular application.

[0038] According to the present invention, a vehicle heat pump system is provided, the vehicle heat pump system comprising: a heat loop including a compressor; a first portion of the heat loop including an external heat exchanger; a second portion of the heat loop including a passenger compartment heat exchanger; an eight-way valve located downstream of the compressor and having a first position and a second position, wherein in the first position refrigerant flows in a portion in a cooling mode, and in the second position refrigerant flows in a portion in a heating mode; and a controller for switching the eight-way valve between the first position and the second position; wherein the external heat exchanger operates as a condenser in the cooling mode, and the eight-way valve directs refrigerant flow from the external heat exchanger to the passenger compartment heat exchanger, and wherein the external heat exchanger operates as an evaporator in the heating mode, and the eight-way valve directs refrigerant flow from the passenger compartment heat exchanger to the external heat exchanger.

[0039] According to an embodiment, the invention is further characterized by: an air-side heater, which, when a sensor detects a temperature below a predetermined threshold, supplements heat in a heating mode to deliver it to the passenger compartment, or reheats the dehumidified air to a predetermined temperature in a dehumidification and reheating mode; and a mixing door, which controls the temperature of the air supplied to the passenger compartment.

[0040] According to an embodiment, the portion further includes: an expansion device for reducing the pressure of the refrigerant flow; an internal heat exchanger located upstream of the expansion device; a flash tank located downstream of the expansion device to separate the vapor-liquid mixture; and a control valve located downstream of the flash tank to balance the pressure of the refrigerant flowing from the flash tank and the eight-way valve.

[0041] According to an embodiment, the eight-way valve includes a valve cover having eight ports.

[0042] According to an embodiment, an eight-way valve is arranged with a first portion and a second portion to influence the phase transition state of the refrigerant, wherein the components of the portions are arranged with each other to influence the phase transition state of the refrigerant, wherein the refrigerant is in liquid or liquid-vapor mixture form when flowing to a compartment heat exchanger in cooling mode, and in vapor form when flowing to a compartment heat exchanger in heating mode.

[0043] According to the embodiments, the refrigerant is one of R134a, R1234yf, R152a, R410A, hydrocarbon, ammonia and R744.

[0044] According to an embodiment, the second part of the thermal loop also includes a flash tank arranged with the eight-way valve to substantially remove vapor from the refrigerant, such that the refrigerant is substantially entirely liquid when entering a cabin heat exchanger in cooling mode or an external heat exchanger in heating mode.

[0045] According to an embodiment, the thermal loop includes only two heat exchangers and only one expansion device.

[0046] According to the present invention, a vehicle heat pump system is provided, the vehicle heat pump system having a compressor configured to increase refrigerant pressure through an external heat exchanger in a cooling mode, which defines a first position of a multi-position valve, and to increase refrigerant pressure through a passenger compartment heat exchanger in a heating mode, which defines a second position of a multi-position valve, wherein the compressor and the multi-position valve are arranged such that the refrigerant pressure is substantially the same in the cooling mode and the heating mode.

[0047] According to an embodiment, the invention is further characterized by an expansion device, a flash tank, and a control valve, which are arranged together to balance the pressure of the refrigerant flowing into and out of the heat exchanger.

[0048] According to an embodiment, the invention is further characterized by a sensor, a controller, and an air-side heater in fluid communication with a compartment heat exchanger, wherein the controller is programmed to activate the air-side heater to provide supplemental heat to the compartment in response to the sensor detecting a temperature below a predetermined threshold.

[0049] According to an embodiment, the refrigerant associated with the refrigerant pressure is one of R134a, R1234yf, R152a, R410A, hydrocarbon, ammonia, and R744.

[0050] According to an embodiment, the invention is further characterized by a flash tank and a compartment heat exchanger, wherein the flash tank is arranged with a multi-position valve such that the refrigerant is substantially entirely liquid when entering the compartment heat exchanger in cooling mode.

[0051] According to an embodiment, the invention is further characterized by having only two heat exchangers and only one expansion device.

[0052] According to the present invention, a vehicle heat pump system is provided, the vehicle heat pump system having a pair of conduit portions of a heat loop and components in fluid communication with each other, including only one internal heat exchanger, a compressor, an external heat exchanger, a passenger compartment heat exchanger, only one expansion device, a flash tank, only one control valve, and an eight-way valve arranged within the pair of conduit portions to switch between a first position in a cooling mode and a second position in a heating mode, wherein refrigerant flows directly from the external heat exchanger to the internal heat exchanger in the cooling mode, and refrigerant flowing out of the external heat exchanger in the heating mode is pressure balanced by only one control valve leading to the internal heat exchanger in the heating mode.

[0053] According to an embodiment, refrigerant flows directly from the compressor to an external heat exchanger in cooling mode, and refrigerant also flows directly from the compressor to a vehicle compartment heat exchanger in heating mode.

[0054] According to an embodiment, the invention is further characterized by an air-side heater, wherein when the compartment heat exchanger operates as a condenser, the air-side heater supplements the heat distribution of the compartment in a heating mode, or when the compartment heat exchanger operates as an evaporator, the dehumidified air is reheated to a predetermined temperature in a dehumidification and reheating mode.

[0055] According to an embodiment, the external heat exchanger operates as a condenser in cooling mode and as an evaporator in heating mode.

[0056] According to an embodiment, the flash tank is arranged with an eight-way valve so that the refrigerant flowing to the compartment heat exchanger in cooling mode or to the external heat exchanger in heating mode is essentially a liquid.

[0057] According to an embodiment, the eight-way valve includes a valve cover having eight ports, a first pair of the eight ports being disposed on a first side of the valve cover opposite to a second pair of the eight ports being disposed on a second side of the valve cover, and wherein four of the eight ports are disposed on a third side of the valve cover.

Claims

1. A vehicle heat pump system, the vehicle heat pump system comprising: Including the compressor's thermal loop; The first thermal section of the thermal loop includes an external heat exchanger. The second thermal section of the thermal loop includes a carriage heat exchanger; An eight-way valve is located downstream of the compressor and has a first position and a second position, in which refrigerant flows in the first hot section and the second hot section in a cooling mode, while in the second position the refrigerant flows in the first hot section and the second hot section in a heating mode. A controller for switching the eight-way valve between the first position and the second position; An expansion device for reducing the pressure of a refrigerant flow; A flash tank, located downstream of the expansion device, is used to separate the vapor-liquid mixture; as well as A control valve, located downstream of the flash tank, In the cooling mode, the external heat exchanger operates as a condenser, and the eight-way valve directs the refrigerant flow from the external heat exchanger to the passenger compartment heat exchanger. In the heating mode, the external heat exchanger operates as an evaporator, and the eight-way valve directs the refrigerant flow from the passenger compartment heat exchanger to the external heat exchanger. The flash tank is arranged with the eight-way valve to substantially remove vapor from the refrigerant, such that when the refrigerant enters the passenger compartment heat exchanger in the cooling mode or the external heat exchanger in the heating mode, the refrigerant is substantially entirely liquid, and the pressure of the refrigerant flowing from the flash tank and the eight-way valve is balanced by a control valve located downstream of the flash tank.

2. The vehicle heat pump system of claim 1, further comprising an air-side heater, wherein when a sensor detects a temperature below a predetermined threshold, the air-side heater operates in the heating mode to supplement heat for delivery to the passenger compartment, or operates in a dehumidification and reheating mode to reheat dehumidified air to a predetermined temperature.

3. The vehicle heat pump system of claim 1, wherein the vehicle heat pump system further includes an internal heat exchanger located upstream of the expansion device.

4. The vehicle heat pump system of claim 3, wherein the eight-way valve is arranged with the first and second heating sections to influence the phase transition state of the refrigerant, wherein components of the first and second heating sections are arranged with each other to influence the phase transition state of the refrigerant, wherein the refrigerant is in liquid or liquid-vapor mixture form when flowing to the passenger compartment heat exchanger in the cooling mode, and in vapor form when flowing to the passenger compartment heat exchanger in the heating mode.

5. The vehicle heat pump system of claim 1, wherein the refrigerant is one of R134a, R1234yf, R152a, R410A, hydrocarbon, ammonia, and R744.

6. The vehicle heat pump system of claim 1, wherein the vehicle heat pump system comprises only two heat exchangers and only one expansion device.

7. A vehicle heat pump system, the vehicle heat pump system comprising: Carriage heat exchanger and external heat exchanger; A multi-position valve having a first position and a second position; A compressor located upstream of a multi-position valve and configured to increase refrigerant pressure through an external heat exchanger in a cooling mode, the cooling mode defining a first position of the multi-position valve, and to increase refrigerant pressure through a passenger compartment heat exchanger in a heating mode, the heating mode defining a second position of the multi-position valve. An expansion device for reducing the pressure of a refrigerant flow; A flash tank, located downstream of the expansion device, is used to separate the vapor-liquid mixture; as well as A control valve, located downstream of the flash tank, The compressor and the multi-position valve are arranged such that the refrigerant pressure is substantially the same in the cooling mode and the heating mode. The flash tank is arranged with the multi-position valve to substantially remove vapor from the refrigerant, such that the refrigerant is substantially entirely liquid when it enters the vehicle compartment heat exchanger in the cooling mode or the external heat exchanger in the heating mode. The pressure of the refrigerant flowing from the flash tank and the multi-position valve is balanced by the control valve located downstream of the flash tank.

8. The vehicle heat pump system of claim 7, wherein the multi-position valve is arranged with the compressor, the passenger compartment heat exchanger, and the external heat exchanger to facilitate a phase transition of the refrigerant as it flows through the passenger compartment heat exchanger and the external heat exchanger, and the expansion device is used to convert the refrigerant into a mixture of vapor and liquid such that the refrigerant is a mixture of vapor and liquid when it flows to the flash tank.

9. The vehicle heat pump system of claim 7, further comprising a sensor, a controller, and an air-side heater in fluid communication with the passenger compartment heat exchanger, wherein the controller is configured to activate the air-side heater to provide supplemental heat to the passenger compartment in response to the sensor detecting a temperature below a predetermined threshold.

10. The vehicle heat pump system of claim 7, wherein the refrigerant associated with the refrigerant pressure is one of R134a, R1234yf, R152a, R410A, hydrocarbon, ammonia, and R744.

11. The system of claim 7, wherein the vehicle heat pump system comprises only two heat exchangers and only one expansion device.

12. A vehicle heat pump system, the vehicle heat pump system comprising: The thermal loop comprises a pair of conduit sections and components in fluid communication with each other, including only one internal heat exchanger, a compressor, an external heat exchanger, a compartment heat exchanger, only one expansion device, a flash tank, only one control valve, and an eight-way valve. The eight-way valve is arranged within the pair of conduit sections to switch between a first position in a cooling mode and a second position in a heating mode. The flash tank is located downstream of the only expansion device to separate the vapor-liquid mixture. The eight-way valve is located downstream of the compressor, and the only control valve is located downstream of the flash tank. The refrigerant flows directly from the external heat exchanger to the internal heat exchanger in the cooling mode, and the refrigerant flowing out of the external heat exchanger in the heating mode is pressure balanced by a single control valve leading to the internal heat exchanger in the heating mode. The flash tank is arranged with the eight-way valve to substantially remove vapor from the refrigerant, such that the refrigerant is substantially entirely liquid when it enters the compartment heat exchanger in the cooling mode or the external heat exchanger in the heating mode.

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