Coolant loop based heat pump for vehicle thermal management

Abstract

A thermal management system for an electric vehicle includes a coolant circuit having a pump configured to circulate coolant in the coolant circuit and one or more valves. A controller is adapted to control respective positions of the one or more valves for modifying a coolant pathway in the coolant circuit. The system includes a coolant-to-refrigerant (C2R) heat exchanger fluidly connected to a coolant circuit and a refrigerant circuit. A low temperature radiator is located in the coolant circuit downstream of the C2R heat exchanger. A coolant heater is positioned in the coolant circuit downstream of the cryogenic heat sink, and a compressor is positioned in the refrigerant circuit. The controller is adapted to minimize energy usage for cabin heating in the electric vehicle by minimizing a respective load of the coolant heater, maximizing a respective load of the compressor, and maintaining a threshold suction pressure for compressor operation.

Description

Technical Field

[0001] The present disclosure generally relates to thermal management systems for electric vehicles. More specifically, the present disclosure relates to a coolant loop-based heat pump for thermal management in electric vehicles. Background Art

[0002] Over the past few years, the use of mobile platforms that employ rechargeable energy sources (both as dedicated and non-dedicated energy sources) has increased significantly. Rechargeable energy storage devices with battery packs can store and release electrochemical energy as needed during a given operating mode. Electrochemical energy can be used for propulsion, heating or cooling the cabin compartment, powering vehicle accessories, and other purposes. During cold weather, a relatively large amount of energy may be consumed to heat the cabin compartment. Summary of the Invention

[0003] Disclosed herein is a thermal management system for an electric vehicle. The system includes a coolant circuit having a pump and one or more valves configured to circulate a coolant in the coolant circuit. A controller is adapted to control the respective positions of the one or more valves to modify the coolant path in the coolant circuit. The controller includes a processor and a tangible, non-transitory memory on which instructions are recorded. A coolant-to-refrigerant (C2R) heat exchanger is fluidly connected to the coolant circuit and the refrigerant circuit. The C2R heat exchanger is configured to transfer heat between the coolant circulating in the coolant circuit and the refrigerant circulating in the refrigerant circuit.

[0004] A low-temperature radiator is located in the coolant circuit, downstream of the C2R heat exchanger. The low-temperature radiator is adapted to extract heat from ambient air to warm the coolant when the coolant temperature is below ambient temperature. A coolant heater is located in the coolant circuit, downstream of the low-temperature radiator, and a compressor is located in the refrigerant circuit. A controller is adapted to minimize energy usage for cabin heating in an electric vehicle by minimizing a corresponding load on the coolant heater, maximizing a corresponding load on the compressor, and maintaining a threshold suction pressure for compressor operation.

[0005] In some embodiments, the threshold suction pressure is between 120 kPa and 140 kPa, and the target load of the compressor is between 4000 rpm and 5000 rpm. The controller is adapted to identify a target coolant temperature at a corresponding inlet of the C2R heat exchanger in response to an input signal indicating a demand for cabin heating. The controller is adapted to increase the corresponding load of the coolant when the coolant temperature at the corresponding inlet of the C2R heat exchanger is at or above the target temperature. The target temperature may be between -5 degrees Celsius and -9 degrees Celsius.

[0006] The controller may be adapted to direct the coolant path through the low-temperature radiator when the coolant temperature at the respective inlet of the low-temperature radiator is below the ambient temperature. The controller may be adapted to direct the coolant path around the low-temperature radiator when the coolant temperature at the respective inlet of the low-temperature radiator is at or above the ambient temperature. The controller may be adapted to increase the compressor load if the low-side refrigerant pressure is at or above a threshold suction pressure, and to decrease the compressor load if the low-side refrigerant pressure is below the threshold suction pressure.

[0007] The system may include a rechargeable energy storage system (RESS) segment located in the coolant loop downstream of the low-temperature radiator, the RESS segment having a traction battery pack. The controller may be adapted to direct the coolant path through the RESS segment when the coolant temperature at the respective inlet of the RESS segment is below the RESS temperature, the coolant receiving heat from the RESS segment. The controller may be adapted to direct the coolant path around the RESS segment when the coolant temperature at the respective inlet of the RESS segment is at or above the RESS temperature.

[0008] A power electronics (PE) section may be located in the coolant circuit, downstream of the low-temperature radiator. The controller may be adapted to direct the coolant path through the PE section when the coolant temperature at the corresponding inlet of the PE section is lower than the PE section temperature, with the coolant receiving heat from the PE section. The controller may be adapted to direct the coolant path around the PE section when the coolant temperature at the corresponding inlet of the PE section is at or above the PE section temperature.

[0009] The system may include a surge tank adapted to store additional coolant, the controller adapted to selectively draw additional coolant into the coolant circuit. In some embodiments, a condensing heater is located in the refrigerant circuit downstream of the compressor, the condensing heater adapted to transfer heat to the vehicle cabin.

[0010] Disclosed herein is a method for thermal management in an electric vehicle, the electric vehicle having a controller and a coolant circuit, the controller having a processor and tangible, non-transitory memory. The method includes circulating a coolant in a coolant circuit via a pump, the coolant circuit having one or more valves. The method includes modifying a coolant path by controlling the respective positions of the one or more valves via the controller. The method includes transferring heat between a coolant circulating in the coolant circuit and a refrigerant circulating in the refrigerant circuit via a coolant-to-refrigerant (C2R) heat exchanger fluidly connected to the coolant circuit and the refrigerant circuit. The method includes, when the coolant temperature is below ambient temperature, extracting heat from ambient air to warm the coolant via a low-temperature radiator located in the coolant circuit, downstream of the C2R heat exchanger. The method includes positioning a coolant heater in the coolant circuit, downstream of the low-temperature radiator, and positioning a compressor in the refrigerant circuit. The method includes minimizing energy usage for cabin heating in the electric vehicle by minimizing a respective load on the coolant heater, maximizing a respective load on the compressor, and maintaining a threshold suction pressure for compressor operation via the controller.

[0011] This application may also include the following options:

[0012] Solution 1. A thermal management system for an electric vehicle, the system comprising: a coolant circuit having a pump and one or more valves configured to circulate coolant in the coolant circuit; a controller adapted to control respective positions of the one or more valves for modifying the coolant pathway, the controller having a processor and tangible, non-transitory memory having instructions recorded thereon; a coolant-to-refrigerant (C2R) heat exchanger fluidly connected to the coolant circuit and the refrigerant circuit, the C2R heat exchanger configured to transfer heat between the coolant circulating in the coolant circuit and the refrigerant circulating in the refrigerant circuit; a low-temperature radiator located in the coolant circuit downstream of the C2R heat exchanger, the low-temperature radiator being adapted to extract heat from ambient air to warm the coolant when the coolant temperature is lower than the ambient temperature; a compressor and a coolant heater, the compressor being located in the refrigerant circuit and the coolant heater being located in the coolant circuit downstream of the low-temperature radiator; and Wherein the controller is adapted to minimize energy usage for cabin heating in the electric vehicle by minimizing a corresponding load on the coolant heater, maximizing a corresponding load on the compressor, and maintaining a threshold suction pressure for compressor operation.

[0013] Option 2. The system of Option 1, wherein the controller is adapted to: identifying a target temperature for the coolant at a respective inlet of the C2R heat exchanger in response to an input signal indicative of a demand for cabin heating; and When the coolant temperature at the corresponding inlet of the C2R heat exchanger is at or above the target temperature, the corresponding load of the coolant is increased.

[0014] Option 3. The system of Option 2, wherein the target temperature is between -5 degrees Celsius and -9 degrees Celsius.

[0015] Option 4. The system of Option 1, wherein the controller is adapted to: directing the coolant path to flow through the low-temperature radiator when the coolant temperature at the corresponding inlet of the low-temperature radiator is lower than the ambient temperature; and When the coolant temperature at the corresponding inlet of the low-temperature radiator is at or above the ambient temperature, the coolant path is directed to bypass the low-temperature radiator.

[0016] Option 5. The system according to Option 1, wherein the controller is adapted to: increasing the compressor load if the low-side refrigerant pressure is at or above the threshold suction pressure; and If the low-side refrigerant pressure is below the threshold suction pressure, the compressor load is reduced.

[0017] Solution 6. The system according to solution 1, further comprising: a rechargeable energy storage system (RESS) section located in the coolant circuit downstream of the low-temperature radiator, the RESS section having a traction battery pack, the controller being adapted to: directing the coolant path through the RESS segment when the coolant temperature at the respective inlets of the RESS segment is lower than the RESS temperature, the coolant receiving heat from the RESS segment; and The coolant path is directed around the RESS segment when the coolant temperature at the respective inlet of the RESS segment is at or above the RESS temperature.

[0018] Embodiment 7. The system of embodiment 1, wherein the threshold suction pressure is between 120 kPa and 140 kPa, and the target load of the compressor is between 4000 rpm and 5000 rpm.

[0019] Solution 8. The system according to solution 1, further comprising: a power electronics (PE) section located in the coolant circuit downstream of the low-temperature radiator; and Wherein, the controller is suitable for: When the coolant temperature at the corresponding inlet of the PE section is lower than the PE section temperature, directing the coolant path to flow through the PE section, the coolant receiving heat from the PE section; and When the coolant temperature at the corresponding inlet of the PE section is at or above the PE section temperature, the coolant path is directed to bypass the PE section.

[0020] Solution 9. The system according to solution 1, further comprising: A surge tank is adapted to store additional coolant, and the controller is adapted to selectively draw the additional coolant into the coolant circuit.

[0021] Solution 10. The system according to solution 1, further comprising: A condensing heater is located in the refrigerant circuit downstream of the compressor, the condensing heater being adapted to transfer heat to a vehicle cabin.

[0022] Embodiment 11. A method for thermal management in an electric vehicle having a coolant circuit and a controller having a processor and tangible, non-transitory memory, the method comprising: circulating a coolant in the coolant circuit via a pump, the coolant circuit having one or more valves; modifying a coolant path by controlling respective positions of the one or more valves via the controller; transferring heat between the coolant circulating in the coolant circuit and the refrigerant circulating in the refrigerant circuit via a coolant-to-refrigerant (C2R) heat exchanger fluidly connected to the coolant circuit and the refrigerant circuit; When the coolant temperature is lower than the ambient temperature, extracting heat from the ambient air through a low-temperature radiator located in the coolant circuit downstream of the C2R heat exchanger to warm the coolant; positioning a coolant heater in the coolant circuit downstream of the low temperature radiator and positioning a compressor in the refrigerant circuit; and Energy usage for cabin heating in the electric vehicle is minimized by minimizing a corresponding load on the coolant heater, maximizing a corresponding load on the compressor, and maintaining a threshold suction pressure for compressor operation via the controller.

[0023] Option 12. The method according to Option 11, further comprising: identifying a target temperature for the coolant at a respective inlet of the C2R heat exchanger in response to an input signal indicating a demand for cabin heating, the target temperature being between -5 degrees Celsius and -9 degrees Celsius; and When the coolant temperature at the corresponding inlet of the C2R heat exchanger is at or above the target temperature, the corresponding load of the coolant is increased.

[0024] Option 13. The method according to Option 11, further comprising: directing the coolant path to flow through the low-temperature radiator when the coolant temperature at the corresponding inlet of the low-temperature radiator is lower than the ambient temperature; and When the coolant temperature at the corresponding inlet of the low-temperature radiator is at or above the ambient temperature, the coolant path is directed to bypass the low-temperature radiator.

[0025] Solution 14. The method according to solution 11, further comprising: increasing the compressor load if the low-side refrigerant pressure is at or above the threshold suction pressure, the threshold suction pressure being between 120 kPa and 140 kPa; and If the low-side refrigerant pressure is lower than the threshold suction pressure, the compressor load is reduced, with a target load of the compressor being between 4,000 rpm and 5,000 rpm.

[0026] Option 15. The method according to Option 11, further comprising: positioning a rechargeable energy storage system (RESS) section in the cooling circuit downstream of the low-temperature radiator, the RESS section having a traction battery pack; directing the coolant path through the RESS segment when the coolant temperature at the respective inlets of the RESS segment is lower than the RESS temperature, the coolant receiving heat from the RESS segment; and The coolant path is directed around the RESS segment when the coolant temperature at the respective inlet of the RESS segment is at or above the RESS temperature.

[0027] Option 16. The method according to Option 11, further comprising: positioning a powertrain drive unit (PDU) in the cooling circuit downstream of the low-temperature radiator; When the coolant temperature at the corresponding inlet of the PDU is lower than the PDU temperature, directing the coolant path to flow through the PDU, the coolant receiving heat from the PDU; and When the coolant temperature at the corresponding inlet of the PDU is at or above the PDU temperature, the coolant path is directed to bypass the PDU.

[0028] Solution 17. An electric vehicle, comprising: a coolant circuit having a pump configured to circulate coolant in the coolant circuit; one or more valves adapted to modify the path of the coolant in the coolant circuit; a controller adapted to select respective positions of the one or more valves, the controller having a processor and tangible, non-transitory memory having instructions recorded thereon; a refrigerant circuit in thermal communication with the coolant circuit, the refrigerant circuit having a compressor; a coolant-to-refrigerant (C2R) heat exchanger fluidly connected to the coolant circuit and the refrigerant circuit, the C2R heat exchanger configured to transfer heat between the coolant circulating in the coolant circuit and the refrigerant circulating in the refrigerant circuit; a low-temperature radiator located in the coolant circuit downstream of the C2R heat exchanger, the low-temperature radiator being adapted to extract heat from the ambient air to warm the coolant when the corresponding temperature of the coolant is lower than the ambient temperature; a coolant heater located in the coolant circuit downstream of the low-temperature radiator; and Wherein, the controller is suitable for: identifying a target temperature for the coolant at a respective inlet of the C2R heat exchanger in response to an input signal indicative of a demand for cabin heating in the electric vehicle; When the coolant temperature at the corresponding inlet of the C2R heat exchanger is at or above the target temperature, increasing the corresponding load of the coolant; and Energy usage for cabin heating is minimized by maximizing a corresponding load on the compressor, minimizing a corresponding load on the coolant heater, and maintaining a threshold suction pressure for compressor operation.

[0029] Option 18. The electric vehicle according to Option 17, wherein the controller is adapted to: directing the coolant path to flow through the low-temperature radiator when the coolant temperature at the corresponding inlet of the low-temperature radiator is lower than the ambient temperature; and When the coolant temperature at the corresponding inlet of the low-temperature radiator is at or above the ambient temperature, the coolant path is directed to bypass the low-temperature radiator.

[0030] Option 19. The electric vehicle according to Option 17, wherein the controller is adapted to: increasing the compressor load if the low-side refrigerant pressure is at or above the threshold suction pressure; and If the low-side refrigerant pressure is below the threshold suction pressure, the compressor load is reduced.

[0031] Option 20. The electric vehicle according to Option 17, further comprising: a rechargeable energy storage system (RESS) section located in the coolant circuit downstream of the low-temperature radiator, the RESS section having a traction battery pack, the controller being adapted to: directing the coolant path through the RESS segment when the coolant temperature at the respective inlets of the RESS segment is lower than the RESS temperature, the coolant receiving heat from the RESS segment; and The coolant path is directed around the RESS segment when the coolant temperature at the respective inlet of the RESS segment is at or above the RESS temperature.

[0032] The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of a coolant-based heat pump system in a vehicle, the system having a controller;

[0034] Figure 2 is able to be Figure 1 A schematic flow chart of a method performed by a controller;

[0035] Figure 3yes Figure 1 a schematic diagram of a portion of a system; and

[0036] Figure 4 It is a schematic coordinate diagram of pressure versus enthalpy in a refrigeration cycle.

[0037] Representative embodiments of the present disclosure are shown in the accompanying drawings by way of non-limiting examples and are described in further detail below. However, it should be understood that the novel aspects of the present disclosure are not limited to the specific forms illustrated in the accompanying drawings listed above. On the contrary, the present disclosure is intended to cover modifications, equivalents, combinations, sub-combinations, permutations, groupings, and alternatives that fall within the scope of the present disclosure, such as those encompassed by the appended claims. DETAILED DESCRIPTION

[0038] Referring to the drawings, wherein like reference numerals refer to like parts, Figure 1 A thermal management system 10 (hereinafter referred to as the "system") for an electric vehicle 12 is schematically illustrated. As described below, the system 10 includes a coolant loop-based heat pump 14 that improves the range of the electric vehicle 12 during cold ambient conditions. The electric vehicle 12 can be partially electric or fully electric. The electric vehicle 12 can be a mobile platform such as, but not limited to, a passenger vehicle, a sport utility vehicle, a light truck, a heavy vehicle, an ATV, a minivan, a bus, a transit vehicle, a bicycle, a mobile robot, an agricultural implement (e.g., a tractor), sports-related equipment (e.g., a golf cart), a boat, an airplane, and a train. It should be understood that the electric vehicle 12 can take many different forms.

[0039] refer to Figure 1 The coolant circuit 16 includes a pump 18 configured to circulate a coolant 20 in the coolant circuit 16. The coolant 20 may be a water-based coolant containing additives for various purposes (e.g., antifreeze). The coolant circuit may employ an oil-based coolant. In one embodiment, the coolant 20 is ethylene glycol. Figure 3 A portion of the system 10 is shown. Figure 1 and Figure 3 A coolant-to-refrigerant (C2R) heat exchanger 22 (also referred to as a chiller 22) is fluidly connected to the coolant circuit 16 and the refrigerant circuit 24. The C2R heat exchanger 22 is configured to transfer heat between the coolant circulating in the coolant circuit and the refrigerant 26 circulating in the refrigerant circuit. In some embodiments, the C2R heat exchanger 22 is a compact plate-to-plate heat exchanger.

[0040] refer to Figure 1, the coolant circuit 16 includes a buffer tank 28, which serves as a regulating component for the amount of coolant 20 in the coolant circuit 16. Coolant overflow can be directed toward the buffer tank 28 via a path 30. Figure 1 and Figure 3 A low-temperature radiator 32 is located downstream of the C2R heat exchanger 22. As described below, the low-temperature radiator 32 is adapted to extract heat from the ambient air to warm the coolant 20 circulating in the coolant loop when the coolant temperature is lower than the ambient temperature. The low-temperature radiator 32 may be configured with channels or tubes for circulating the coolant therein, and metal fins to facilitate heat transfer.

[0041] As will be appreciated by those skilled in the art, low temperature radiators operate within a lower temperature range than conventional radiators. For example, the low temperature radiator 32 may be adapted to operate within a range of approximately 25 degrees Celsius to 60 degrees Celsius. In one embodiment, the low temperature radiator 32 has an operating range of 40 degrees Celsius to 50 degrees Celsius.

[0042] refer to Figure 1 The system 10 includes a controller C having at least one processor P and at least one memory M (or a non-transitory, tangible computer-readable storage medium), on which is recorded the instructions for executing the following instructions: Figure 2 Instructions for the method 100 of operating the coolant loop based heat pump 14 are described. The memory M may store an executable instruction set, and the processor P may execute the instruction set stored in the memory M.

[0043] refer to Figure 1 The coolant circuit 16 includes one or more valves (e.g., a first valve 34A and a second valve 34B), each having a corresponding variable position. The controller C is adapted to adjust or control the respective positions of the valves to modify the path of the coolant along the coolant circuit 16, referred to herein as the coolant path. For example, the controller C is adapted to modify the position of the first valve 34A to direct the coolant path around the low-temperature radiator 32 (via coolant path A1) when the coolant temperature at the inlet 31 of the low-temperature radiator 32 is at or above ambient temperature.

[0044] refer to Figure 1 The coolant circuit 16 includes a rechargeable energy storage system (herein referred to as the RESS section 36) having a traction battery pack used to power the electric vehicle 12. The battery cells in the RESS section 36 may have different chemistries, including but not limited to lithium-ion batteries, lithium-iron batteries, nickel-metal hydride batteries, and lead-acid batteries. It should be understood that the configuration, number, and type of battery cells in the RESS section 36 may vary based on the application at hand.

[0045] refer to Figure 1 A powertrain drive unit (PDU) 38 and a power electronics (PE) section 40 are each positioned downstream of the low-temperature radiator 32 in the coolant loop. The PDU 38 includes an electric motor (not shown) that transmits torque to the wheels of the electric vehicle 12. The PE section 40 generally includes a traction power inverter module, an auxiliary power module, and / or an onboard charging module (not shown).

[0046] refer to Figure 1 and Figure 3 The coolant heater 42 is positioned in the coolant circuit 16 downstream of the low temperature radiator 32. The refrigerant circuit 24 includes Figure 1 and Figure 3 An expansion valve 44 is shown in FIG. 4 , which is adapted to control the flow of the refrigerant 26 . The expansion valve 44 may also reduce the pressure on the refrigerant 26 .

[0047] refer to Figure 3 The refrigerant circuit 24 includes a compressor 46 located downstream of the C2R heat exchanger 22. The compressor 46 compresses the refrigerant 26, converting it into a heated, high-pressure gas that is pumped into a condensing heater 48. As the refrigerant 26 moves through the condensing heater 48, converting from a liquid to a gas, heat is released and discharged into the vehicle cabin 50. The high-voltage accessory load for cabin heating is a combination of the compressor load and the coolant heater load. Therefore, there is a trade-off between the compressor load during high-speed compressor operation in the refrigeration circuit 24 and the resistive load of the coolant heater 42 in the coolant circuit 16 for cabin heating.

[0048] Controller C is adapted to minimize energy usage by minimizing the corresponding load on coolant heater 42, maximizing the corresponding load on compressor 46, and maintaining a threshold suction pressure for compressor operation. Because refrigerant circuit 24 is relatively more efficient, this mode of operation reduces the overall high voltage accessory load consumed by cabin heating.

[0049] The system 10 identifies a target temperature for the coolant 20 at the inlet 21 of the C2R heat exchanger 22 in response to an input signal indicating the cabin heating demand of the electric vehicle 12. When the coolant temperature at the inlet 21 of the C2R heat exchanger 22 is at or above the target temperature, the coolant heater load is increased. The controller C determines the target temperature based on the cabin heating demand of the electric vehicle 12 and the specifications of the various components in the heat pump 14 using a calibration process or simulation / modeling process available to those skilled in the art. The target temperature may be between -5 degrees Celsius and -9 degrees Celsius. In one example, the target temperature is approximately -7 degrees Celsius.

[0050] As discussed below, the system 10 involves mechanization of the coolant circuit 16 and changes in operating modes to ensure that the coolant temperature is elevated before reaching the inlet 21 of the C2F exchanger 22 , either from ambient heat via the low temperature radiator 32 , and / or from waste heat from the RESS section 36 or the powertrain drive unit 38 or the power electronics section 40 .

[0051] Now refer to Figure 2 , showing the storage Figure 1 Flowchart of method 100 on and executable by controller C. Method 100 may be embodied as a flowchart stored in Figure 1 The method 100 is a computer-readable code or instruction that is executed on and in part by the controller C. The method 100 need not be applied in the specific order described herein. Furthermore, it should be understood that some steps may be eliminated. The method 100 may be executed dynamically. The method 100 is not limited to the specific type or configuration of the components described above (e.g., the low-temperature radiator 32, the compressor 46, etc.).

[0052] according to Figure 2 At block 102 , controller C is adapted to receive an input signal indicative of cabin heating demand for the electric vehicle 12 (e.g., for the cabin). Cabin heating varies with refrigerant discharge pressure, which is achieved through the corresponding load on the coolant heater and compressor. From block 102 , method 100 may proceed simultaneously to one or more of blocks 110 , 120 , 130 , and 140 to manage compressor operation, low-temperature radiator bypass operation, RESS bypass operation, and coolant heater operation, respectively.

[0053] According to box 110, the controller C is adapted to determine whether the low-side refrigerant pressure (LSRP) is at or above a threshold suction pressure (SP). If so (box 110=Yes), the method 100 proceeds to box 112, where the controller C is adapted to increase the compressor load. If the low-side refrigerant pressure is below the threshold suction pressure (box 110=No), the controller C is adapted to decrease the compressor load according to box 114.

[0054] According to block 120, the controller C is adapted to determine whether the coolant temperature (CT1) at the inlet 31 of the low-temperature radiator 32 is below the outside ambient temperature (OAT), which is referred to herein as the ambient temperature. If so (block 120 = Yes), the method 100 proceeds to block 122, where the controller C is adapted to direct the coolant path through the low-temperature radiator 32, where the coolant receives heat. If the coolant temperature at the inlet 31 of the low-temperature radiator 32 is at or above the ambient temperature (block 120 = No), the controller C is adapted to modify the position of the first valve 34A, according to block 124, to direct the coolant path around the low-temperature radiator 32 (via coolant path A1) when the coolant temperature at the inlet 31 of the low-temperature radiator 32 is at or above the ambient temperature.

[0055] According to box 130, the controller C is adapted to determine whether the coolant temperature (CT2) at the inlet 35 of the RESS section 36 is lower than the RESS temperature (T1). If so (box 130=yes), the method 100 proceeds to box 132, where the controller C is adapted to direct the coolant path through the RESS section, where the coolant receives waste heat from the RESS section. If not (box 130=no), according to box 134, the controller C is adapted to modify the position of the second valve 34B to direct the coolant path around the RESS section 36 (via coolant path B1).

[0056] According to block 140, the controller C is adapted to determine whether the coolant temperature (CT3) at the inlet 21 of the C2R heat exchanger 22 is below the target temperature. If so (block 140=Yes), the controller C is adapted to increase the corresponding load of the coolant heater 42 according to block 144. If not (block 140=No), the method 100 proceeds to block 142, where the controller C is adapted to maintain (or not increase) the corresponding load of the coolant heater 42. The method 100 may be repeated continuously or at predetermined time intervals during operation of the vehicle 12.

[0057] By extracting heat from the increased coolant volume in the coolant loop 16, for example by increasing the size of the buffer tank 28, an energy benefit can be achieved during the initial phase of heat pump operation. The controller C is adapted to selectively draw excess coolant into the coolant loop 16 to improve heat pump operation by reducing high-voltage accessory loads. For example, an additional 10 liters can ensure heating for approximately 2 minutes, and 20 liters can ensure heating for approximately 3 minutes.

[0058] Now refer to Figure 4, which is a schematic graph with a vertical axis 202 representing pressure (in bar) and a horizontal axis 204 representing enthalpy in kilojoules per kilogram (kJ / kg). Various temperatures (e.g., 0, 20, 40, and 60 degrees Celsius) are indicated by contour lines 206. Curves 208 separate the various phases of the refrigerant (e.g., liquid, solid). Figure 4 As shown in FIG, trace 210 indicates the evaporation process, wherein the coolant temperature at the corresponding inlet of the C2R heat exchanger is approximately 15 degrees Celsius. Trace 212 indicates the compression process, wherein the compressor load is 2000 RPM. Trace 214 and trace 216 indicate the condensation process and the expansion process, respectively. Trace 214 indicates an inlet temperature of -7 degrees Celsius and an outlet temperature of 45 degrees Celsius.

[0059] System 10 can be achieved by Figure 4 The energy minimization path shown by (dashed) lines 220 and 222 in FIG. Line 220 indicates the evaporation process, where the coolant temperature at the corresponding inlet of the C2R heat exchanger is approximately -7 degrees Celsius. Line 222 indicates the compression process, where the compressor load is 4500 RPM, reaching trajectory 214 at point 224. Thus, system 10 minimizes energy usage by minimizing the corresponding load of the coolant heater, maximizing the corresponding load of the compressor, and maintaining a threshold suction pressure for compressor operation.

[0060] refer to Figure 1 , the controller C may be configured to communicate with or access data from a cloud unit 52 via a wireless network 54. The cloud unit 52 may include one or more servers hosted on the Internet to store, manage, and process data. Figure 1 The wireless network 54 may be a wireless local area network (LAN) that links multiple devices using a wireless distribution method, a wireless metropolitan area network (MAN) that connects several wireless LANs, or a wireless wide area network (WAN) that covers a large area such as a neighboring town or city. The wireless network 54 may be WIFI or Bluetooth. TM A connection is defined as a short-range radio technology (or wireless technology) designed to facilitate communications between Internet devices and between devices and the Internet. Other types of connections may be employed.

[0061] In summary, system 10 (via execution of method 100) enables implementation of a heat pump mode operating strategy developed for cabin heating during cold ambient conditions. System 10 reduces voltage loads, thereby increasing the range of electric vehicle 12 in those cold conditions. As used herein, the terms "dynamic" and "dynamically" describe steps or processes that are performed in real time and are characterized by monitoring or otherwise determining the state of a parameter and periodically or periodically updating the state of the parameter during or between iterations of the routine.

[0062] Figure 1 The controller C may be an integral part of the other controllers of the electric vehicle 12 , or a separate module operatively connected to the other controllers of the electric vehicle 12 . Figure 1 The controller C includes a computer-readable medium (also known as a processor-readable medium), which includes a non-transitory (e.g., tangible) medium that participates in providing data (e.g., instructions) that can be read by a computer (e.g., a processor of a computer). Such media can take a variety of forms, including but not limited to non-volatile media and volatile media. Non-volatile media can include, for example, optical or magnetic disks and other permanent memories. Volatile media can include, for example, dynamic random access memory (DRAM), which can constitute main memory. Such instructions can be transmitted by one or more transmission media, including coaxial cables, copper wires, and optical fibers, including lines comprising a system bus connected to the processor of the computer. Some forms of computer-readable media include, for example, floppy disks, floppy disks, hard disks, magnetic tape, other magnetic media, CD-ROMs, DVDs, other optical media, physical media with a pattern of holes, RAM, PROMs, EPROMs, FLASH-EEPROMs, other memory chips or cassettes, or other media from which a computer can read.

[0063] The lookup tables, databases, data repositories or other data stores described herein may include various types of mechanisms for storing, accessing and retrieving various types of data, including hierarchical databases, a set of files in a file system, an application database in a proprietary format, a relational database management system (RDBMS), etc. Each such data store may be included in a computing device that utilizes a computer operating system (such as one of those operating systems mentioned above) and may be accessed via a network in one or more of a variety of ways. The file system may be accessible from a computer operating system and may include files stored in various formats. In addition to the language used to create, store, edit and execute stored procedures, an RDBMS may also employ structured query language (SQL), such as the PL / SQL language mentioned above.

[0064] Figure 2The (one or more) flowchart illustrations shown in the illustrative embodiments of the present invention illustrate the architecture, functions and operations of possible implementations of the systems, methods and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing (one or more) specified logical functions. It will also be noted that each box in the block diagram and / or flowchart illustration and the combination of boxes in the block diagram and / or flowchart illustration can be implemented by a dedicated hardware-based system that performs the specified function or action, or a combination of dedicated hardware and computer instructions. These computer program instructions may also be stored in a computer-readable medium that can instruct a controller or other programmable data processing device to act in a particular manner so that the instructions stored in the computer-readable medium produce an article of manufacture including instructions for implementing the functions / actions specified in the flowchart and / or block diagram boxes.

[0065] The numerical values ​​of parameters (e.g., amounts or conditions) in this specification (including the appended claims) should be understood as being modified by the term "approximately" in each corresponding case, regardless of whether "approximately" actually appears before the numerical value. "Approximately" means that the numerical value allows some slight imprecision (close to the exact value to a certain extent; approximately or reasonably close to the value; almost). If the imprecision provided by "approximately" is not understood to have such ordinary meaning in the art, then the "approximately" used herein at least represents the possible changes that may arise from the ordinary methods of measuring and using such parameters. In addition, the disclosure of a range includes disclosing each value within the entire range and the range further divided. Each value within the range and the endpoints of the range are disclosed here as separate embodiments.

[0066] The detailed description and the accompanying drawings or figures support and describe the present disclosure, but the scope of the present disclosure is limited only by the claims. Although the best mode and some of the other embodiments for carrying out the claimed disclosure have been described in detail, there are various alternative designs and embodiments for practicing the disclosure defined in the appended claims. In addition, the embodiments shown in the drawings or the features of the various embodiments mentioned in this description are not necessarily to be understood as embodiments that are independent of each other. On the contrary, it is possible that each feature described in one of the examples of an embodiment can be combined with one or more other desired features from other embodiments to produce other embodiments that are not described in words or by reference to the drawings. Therefore, such other embodiments fall within the framework of the scope of the appended claims.

Claims

1. A thermal management system for an electric vehicle, the system comprising: a coolant circuit having a pump and one or more valves configured to circulate coolant in the coolant circuit; a controller adapted to control respective positions of the one or more valves for modifying the coolant pathway, the controller having a processor and tangible, non-transitory memory having instructions recorded thereon; a coolant-to-refrigerant (C2R) heat exchanger fluidly connected to the coolant circuit and the refrigerant circuit, the C2R heat exchanger configured to transfer heat between the coolant circulating in the coolant circuit and the refrigerant circulating in the refrigerant circuit; a low-temperature radiator located in the coolant circuit downstream of the C2R heat exchanger, the low-temperature radiator being adapted to extract heat from ambient air to warm the coolant when the coolant temperature is lower than the ambient temperature; a compressor and a coolant heater, the compressor being located in the refrigerant circuit and the coolant heater being located in the coolant circuit downstream of the low-temperature radiator; and Wherein the controller is adapted to minimize energy usage for cabin heating in the electric vehicle by minimizing a corresponding load on the coolant heater, maximizing a corresponding load on the compressor, and maintaining a threshold suction pressure for compressor operation.

2. The system according to claim 1, wherein: The controller is suitable for: identifying a target temperature for the coolant at a respective inlet of the C2R heat exchanger in response to an input signal indicative of a demand for cabin heating; and When the coolant temperature at the corresponding inlet of the C2R heat exchanger is at or above the target temperature, the corresponding load of the coolant is increased.

3. The system according to claim 2, wherein: The target temperature is between -5 degrees Celsius and -9 degrees Celsius.

4. The system according to claim 1, wherein: The controller is suitable for: directing the coolant path to flow through the low-temperature radiator when the coolant temperature at the corresponding inlet of the low-temperature radiator is lower than the ambient temperature; and When the coolant temperature at the corresponding inlet of the low-temperature radiator is at or above the ambient temperature, the coolant path is directed to bypass the low-temperature radiator.

5. The system according to claim 1, wherein: The controller is suitable for: increasing the compressor load if the low-side refrigerant pressure is at or above the threshold suction pressure; and If the low-side refrigerant pressure is below the threshold suction pressure, the compressor load is reduced.

6. The system of claim 1 , further comprising: a rechargeable energy storage system (RESS) section located in the coolant circuit downstream of the low-temperature radiator, the RESS section having a traction battery pack, the controller being adapted to: directing the coolant path through the RESS segment when the coolant temperature at the respective inlets of the RESS segment is lower than the RESS temperature, the coolant receiving heat from the RESS segment; and The coolant path is directed around the RESS segment when the coolant temperature at the respective inlet of the RESS segment is at or above the RESS temperature.

7. The system according to claim 1, wherein: The threshold suction pressure is between 120 kPa and 140 kPa, and the target load of the compressor is between 4000 rpm and 5000 rpm.

8. The system of claim 1 , further comprising: a power electronics (PE) section located in the coolant circuit downstream of the low-temperature radiator; and Wherein, the controller is suitable for: When the coolant temperature at the corresponding inlet of the PE section is lower than the PE section temperature, directing the coolant path to flow through the PE section, the coolant receiving heat from the PE section; and When the coolant temperature at the corresponding inlet of the PE section is at or above the PE section temperature, the coolant path is directed to bypass the PE section.

9. The system of claim 1 , further comprising: A surge tank is adapted to store additional coolant, and the controller is adapted to selectively draw the additional coolant into the coolant circuit.

10. The system of claim 1, further comprising: A condensing heater is located in the refrigerant circuit downstream of the compressor, the condensing heater being adapted to transfer heat to a vehicle cabin.

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