Method and system for managing vehicle thermal conditions

Abstract

The present disclosure relates to methods and systems for managing vehicle thermal conditions. A vehicle climate control system for an electrified vehicle is provided, comprising a thermal circuit and a controller. The thermal circuit comprises a heat pump and a positive temperature coefficient (PTC) heater. The controller is configured to direct the operation of the heat pump and the PTC heater in response to receiving a request for simultaneous cooling and heating based on a heat source mode table and detecting a system configuration that allows flow through one of a fixed orifice expansion device (FOT), a thermal expansion valve (TXV), and an electronic expansion valve (EXV). When the heater core coolant is identified as warm and the ambient temperature is greater than a predetermined threshold, the heat source mode table may require the heat pump to operate in a cooling mode and the PTC heater to operate in a heating mode.

Description

Technical Field

[0001] The present disclosure relates to a heat pump system for assisting in managing thermal conditions of a vehicle. Background Art

[0002] Electrified vehicles such as battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), mild hybrid electric vehicles (MHEVs), or full hybrid electric vehicles (FHEVs) include energy storage devices such as high voltage batteries to serve as a propulsion source for the vehicle. The high voltage battery may include components and systems for assisting in managing vehicle performance and operation. The vehicle cabin climate control system may operate in conjunction with the engine thermal management system to provide efficient heat distribution via refrigerants and coolants flowing throughout the heat pump system. The control system may direct the operation of the various components of the climate control system and thermal management system based on inputs received from sensors monitoring vehicle and ambient conditions. Summary of the invention

[0003] A vehicle climate control system for an electrified vehicle includes a thermal circuit and a controller. The thermal circuit includes a heat pump and a positive temperature coefficient (PTC) heater. The controller is configured to: in response to receiving a request for simultaneous cooling and heating based on a heat source mode table and detecting a system configuration that allows flow through one of a fixed orifice expansion device (FOT), a thermal expansion valve (TXV), and an electronic expansion valve (EXV), direct the operation of the heat pump and the PTC heater. When the heater core coolant is identified as warm and the ambient temperature is greater than a predetermined threshold, the heat source mode table may require the heat pump to operate in a cooling mode and require the PTC heater to operate in a heating mode. When the heater core coolant is identified as hot and the ambient temperature is greater than a predetermined threshold, the heat source mode table may require the heat pump to operate in a cooling mode and require the PTC heater to be deactivated. When the heater core coolant is identified as warm and the ambient temperature is less than or equal to a predetermined threshold, the heat source mode table may require the PTC heater to output heat. The activation of simultaneous cooling and heating operations may also be based on a relationship between the heater core coolant temperature and the target heater core coolant temperature, a climate heating request, a climate cooling request, and the ambient temperature. The heater core coolant temperature can be measured by a sensor and input into the heat source mode table as one of cold, warm and hot based on a calibrable constant. During cooling mode, the operating state of the FOT, TXV or EXV can be enabled. During heating mode, the operating state of the FOT, TXV or EXV can be disabled. The vehicle climate control system can include another FOT, TXV or EXV. During dehumidification mode, the operating state of the FOT, TXV or EXV can be enabled for the cooling expansion device, and the operating state of the other FOT, TXV or EXV can be enabled for the heating expansion device. The operation of the heat pump and the PTC heater can be based on a predetermined temperature threshold and a measured ambient temperature.

[0004] A vehicle climate control system for an electrified vehicle includes a thermal loop and a controller. The thermal loop includes one of a FOT, a TXV, or an EXV, a heat pump, and an auxiliary heat source. The controller is configured to enable the auxiliary heat source based on the operating state of the FOT, TXV, or EXV and a mode command table. During the heating mode, the auxiliary heat source can be enabled, and the FOT, TXV, or EXV can be instructed to operate as enabled. The auxiliary heat source can be a positive temperature coefficient heater. When the temperature of the heater core coolant is identified as warm and the ambient temperature is greater than a predetermined threshold, the mode command table can require the heat pump to operate in a dehumidification mode and require the positive temperature coefficient heater to be disabled. When the heater core coolant is identified as hot and the ambient temperature is greater than a predetermined threshold, the mode command table can require the heat pump to operate in a cooling mode and require the positive temperature coefficient heater to be disabled. When the heater core coolant is identified as cold and the ambient temperature is greater than a predetermined threshold, the mode command table can require the heat pump to operate in a dehumidification mode and require the positive temperature coefficient heater to be disabled. The auxiliary heat source can be an engine.

[0005] A method for operating a vehicle climate control system includes: in response to receiving a cooling mode request and a heating mode request simultaneously, outputting, via a controller, a command to enable an auxiliary heat source based on an ambient temperature and a predetermined calibratable constant temperature. The method may also include: in response to detecting a flow change in one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve, outputting, via the controller, a heat pump operation command to adjust the vehicle climate based on the ambient temperature, a heater core coolant temperature, a target heater core coolant temperature, and a climate control request. The auxiliary heat source may be one of a positive temperature coefficient heater and an engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic representation of an example of a vehicle.

[0007] Figure 2A is a schematic representation of an example of a valve expansion device.

[0008] Figure 2B is a schematic representation of another example of a valve expansion device.

[0009] Figure 3 It is shown in the Figure 1 A table of example component operating states during various operating modes of an example vapor compression heat pump (VCHP) subsystem of a vehicle.

[0010] Figure 4 It is shown for Figure 1 State diagram of an example of the control strategy of the VCHP subsystem of a vehicle.

[0011] Figure 5is a table illustrating an example of a heat pump mode control strategy for a VCHP subsystem including one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve.

[0012] Figure 6 is a flow chart illustrating an example of an algorithm for the operation of the VCHP subsystem. DETAILED DESCRIPTION

[0013] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are only examples, and other embodiments may take various alternative forms. The drawings need not be drawn to scale; some features may be exaggerated or minimized to show the details of specific components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limitations, but only as a representative basis for teaching those skilled in the art to utilize the embodiments of the present disclosure in various forms. As will be understood by those of ordinary skill in the art, the various features shown and described with reference to any of the figures may be combined with the features shown in one or more other figures to produce embodiments that are not explicitly shown or described. The combination of features shown provides representative embodiments for typical applications. However, various combinations and variations of features consistent with the teachings of the present disclosure may be desired for specific applications or implementations.

[0014] In certain situations, electrified vehicles such as BEVs and PHEVs may require an alternative heat source to replace or supplement the amount of heat rejected by a conventional internal combustion engine in order to meet vehicle cabin heating targets. Vapor compression heat pump (VCHP) technology can provide acceptable vehicle cabin heating by extracting energy from the vehicle's surroundings.

[0015] Reference Figure 1 , a schematic diagram of a vehicle 10 is shown. The vehicle 10 may be a motor vehicle, such as a car or a truck. The vehicle 10 may have any suitable drive train and may include one or more power sources 12 that may be used to propel the vehicle 10 and / or provide power to vehicle components. Figure 1 In the figure, the vehicle 10 is shown as having a single power source 12, which can be configured as an internal combustion engine that can be adapted to burn any suitable type of fuel, such as gasoline, diesel fuel, or hydrogen. Alternatively, the vehicle 10 can be configured as a hybrid vehicle that can have multiple power sources, such as an electric power source and a non-electric power source like an engine.

[0016] The vehicle 10 may include a passenger compartment 20, an engine compartment 22, and a climate control system 24. The passenger compartment 20 may be disposed within the vehicle 10 and may accommodate one or more passengers. A portion of the climate control system 24 may be disposed in the passenger compartment 20. The engine compartment 22 may be disposed adjacent to the passenger compartment 20. One or more power sources 12 and a portion of the climate control system 24 may be disposed in the engine compartment 22. The engine compartment 22 may be separated from the passenger compartment 20 by a bulkhead 26. The climate control system 24 may circulate air and / or control or change the temperature of the air circulated in the passenger compartment 20. The climate control system 24 may include a coolant subsystem 30, a heat pump subsystem 32, and a ventilation subsystem 34.

[0017] The coolant subsystem 30 (which may also be referred to as a coolant loop) can circulate a fluid such as a coolant to cool the power source 12. For example, waste heat generated by the power source 12 when the power source is running or operating can be transferred to the coolant and then circulated to one or more heat exchangers, thereby transferring thermal energy from the coolant. In at least one embodiment, the coolant subsystem 30 may include a coolant pump 40, an intermediate heat exchanger 42, a heater core 44, and a bypass loop 48 that can be fluidly interconnected by conduits such as pipes, hoses, and conduits. The coolant subsystem 30 may include a radiator (not shown) that can be disposed in the engine compartment 22 for transferring thermal energy to the ambient air surrounding the vehicle 10. The coolant subsystem 30 may include an auxiliary heat source 49. The auxiliary heat source 49 may be, for example, a positive temperature coefficient (PTC) heater. In embodiments that include an engine, the engine may also operate as an auxiliary heat source.

[0018] The coolant pump 40 can circulate the coolant through the coolant subsystem 30. The coolant pump 40 can be powered by an electric power source or a non-electric power source. For example, the coolant pump 40 can be operably coupled to the power source 12 configured as an internal combustion engine via a belt, or can be driven by an electric motor. The coolant pump 40 can receive coolant from the power source 12 and circulate the coolant in a closed loop. For example, when the climate control system 24 is in a heating mode, the coolant can flow from the coolant pump 40 to the intermediate heat exchanger 42 and then to the heater core 44 before returning to the power source 12, as represented by the arrowed line.

[0019] The intermediate heat exchanger 42 can facilitate the transfer of thermal energy between the coolant subsystem 30 and the heat pump subsystem 32. The intermediate heat exchanger 42 can be part of the coolant subsystem 30 and the heat pump subsystem 32. The intermediate heat exchanger 42 can have any suitable configuration. For example, the intermediate heat exchanger 42 can have a plate-fin, tube-fin, or shell-and-tube configuration that can facilitate the transfer of thermal energy without mixing the heat transfer fluids in the coolant subsystem 30 and the heat pump subsystem 32. When the climate control system 24 is in a heating mode, heat can be transferred from the heat pump subsystem 32 to the coolant via the intermediate heat exchanger 42, as will be discussed in more detail below.

[0020] The heater core 44 can transfer heat energy from the coolant to the air in the passenger compartment 20. The heater core 44 can be disposed in the ventilation subsystem 34 in the passenger compartment 20 and can have any suitable configuration. For example, in one or more embodiments, the heater core 44 can have a plate-fin or tube-fin configuration.

[0021] The coolant subsystem 30 may optionally include an auxiliary heat source 49 for heating the coolant. In at least one embodiment, the auxiliary heat source 49 may be an electric coolant heater, such as a high voltage coolant heater or a low voltage coolant heater, that may be disposed upstream of the heater core 44 and may use electrical energy to heat the coolant. The electric coolant heater may receive power from an electric power source on the vehicle 10 and / or an electric power source remote from the vehicle 10 (such as via an electrical outlet). Alternatively or additionally, the auxiliary heat source 49 may be a non-electric coolant heater, such as a fuel-operated or fuel-driven heater.

[0022] The bypass circuit 48 can guide the coolant so that the coolant is not heated by the power source 12 or the engine. The bypass circuit control valve 50 can control the flow of the coolant through the bypass circuit 48. More specifically, when the bypass circuit control valve 50 is in the first position, the bypass circuit control valve 50 can allow the coolant to flow through the bypass line 52 and prevent the coolant from flowing from the power source 12 to the intermediate heat exchanger 42. In such a position, the second coolant pump 54 can circulate the coolant through the bypass circuit 48, from the intermediate heat exchanger 42 to the heater core 44, to the bypass line 52 and return to the second coolant pump 54. Therefore, in some operating modes, the coolant in the coolant subsystem 30 can be independently heated by the heat pump subsystem 32 via the intermediate heat exchanger 42. The second coolant pump 54 can also be referred to as an auxiliary coolant pump. When the bypass circuit control valve 50 is in the second position, the bypass circuit control valve 50 can also prevent the coolant from flowing through the bypass line 52. The second coolant pump 54 may or may not circulate coolant when coolant is not flowing through the bypass line 52 .

[0023] The heat pump subsystem 32 can transfer heat energy to or from the passenger compartment 20, and transfer heat energy to or from the coolant subsystem 30. In at least one embodiment, the heat pump subsystem 32 can be configured as a VCHP subsystem, wherein a fluid circulates through the heat pump subsystem 32 to transfer heat energy to or from the passenger compartment 20. In this example, the VCHP subsystem can operate with an expansion device. The expansion device can operate in response to a received control signal, for example, operating a motor to selectively switch the operating state of an electronic expansion valve (EXV) between an open position and a closed position of a valve outlet. The heat pump subsystem 32 can operate in various modes, including but not limited to a cooling mode, a heating mode, a dehumidification mode, and a deicing mode.

[0024] In cooling mode, the heat pump subsystem 32 can circulate a heat transfer fluid, which may be referred to as a refrigerant, to transfer thermal energy from inside the passenger compartment 20 to outside the passenger compartment 20. In heating mode, the heat pump subsystem 32 can transfer thermal energy from the refrigerant to the coolant via the intermediate heat exchanger 42 without circulating the refrigerant through a heat exchanger in the passenger compartment 20, as will be discussed in more detail below. For the sake of brevity, a brief discussion of the heat pump subsystem 32 is provided below, which focuses on the vapor compression cycle that may be employed in heating mode. In such a configuration, the heat pump subsystem 32 may include a pump 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 (such as pipes, hoses, etc.). In Figure 1 In FIG. 1 , the refrigerant circulation path in the heating mode is indicated by the line with an arrow.

[0025] Each of the first expansion device 64 and the second expansion device 74 may be a cooling expansion device or a heating expansion device. The first expansion device 64 and the second expansion device 74 may be an EXV. Another example of a VCHP subsystem may operate using an assembly including a fixed orifice expansion device (FOT) or a thermal expansion valve (TXV) instead of an EXV. Figure 2A An example of an assembly 77 is shown in which the first expansion device 64 includes a FOT or TXV 79 and a bypass shutoff valve 81 . Figure 2B An example of an assembly 83 is shown in which the second expansion device 74 includes a FOT or TXV 79 and a shutoff valve 85. In general, the EXV may be replaced by a FOT or TXV and a bypass shutoff valve or shutoff valve in the hot circuit.

[0026] Refer again Figure 1, the pump 60 (which may also be referred to as a compressor) can pressurize the refrigerant and circulate the coolant through the heat pump subsystem 32. The pump 60 can be powered by an electric power source or a non-electric power source. For example, the pump 60 can be operably coupled to the power source 12 configured as an internal combustion engine via a belt, or can be driven by an electric motor. In the heating mode, the pump 60 can provide the high-pressure refrigerant to the intermediate heat exchanger 42, which in turn can transfer heat from the high-pressure refrigerant to the coolant passing through the intermediate heat exchanger 42 to heat the coolant.

[0027] The first control valve 62 can be disposed along a bypass path 80 that can be disposed between the intermediate heat exchanger 42 and the first expansion device 64. When the first control valve 62 is open, the bypass path 80 can allow some refrigerant to bypass the first expansion device 64 and the external heat exchanger 66 and flow to the internal heat exchanger 78 (if provided), the second expansion device 74, and the internal heat exchanger 76. When in a heating mode, the first control valve 62 can be closed to prevent refrigerant from flowing to the internal heat exchanger 76 through the bypass path 80.

[0028] The first expansion device 64 can be disposed between the intermediate heat exchanger 42 and the external heat exchanger 66 and can be fluidly connected to the intermediate heat exchanger 42 and the external heat exchanger 66. The first expansion device 64 can be configured to change the pressure of the refrigerant. The first expansion device 64 can reduce the pressure of the refrigerant passing through the first expansion device 64 from the intermediate heat exchanger 42 to the external heat exchanger 66. Therefore, in the heating mode, the high-pressure refrigerant received from the intermediate heat exchanger 42 can leave the first expansion device 64 at a lower pressure and in the form of a mixture of liquid and vapor.

[0029] The external heat exchanger 66 may be disposed outside the passenger compartment 20. In a cooling mode or air conditioning environment, the external heat exchanger 66 may function as a condenser and may transfer heat to the surrounding environment to condense the refrigerant from a vapor to a liquid. In a heating mode, the external heat exchanger 66 may function as an evaporator and may transfer heat from the surrounding environment to the refrigerant, thereby evaporating the refrigerant.

[0030] The second control valve 68 may be disposed between the external heat exchanger 66 and the bypass path 80. The second control valve 68 may be configured as a check valve and may prevent refrigerant from flowing from the bypass path 80 to the external heat exchanger 66. Thus, when the climate control system 24 is in the heating mode, refrigerant exiting the external heat exchanger 66 may be directed to the third control valve 70.

[0031] A third control valve 70 may be disposed between the external heat exchanger 66 and the accumulator 72. The third control valve 70 may help control the flow of refrigerant exiting the external heat exchanger 66. In a heating mode, the third control valve 70 may be open to allow refrigerant to flow from the external heat exchanger 66 to the accumulator 72. In other modes, such as a cooling mode, the third control valve 70 may be closed and the second expansion device 74 may be open.

[0032] The accumulator 72 may serve as a reservoir for storing any residual liquid refrigerant so that vapor refrigerant rather than liquid refrigerant may be provided to the pump 60. The accumulator 72 may include a desiccant that absorbs a small amount of moisture from the refrigerant.

[0033] The second expansion device 74 can be disposed between the external heat exchanger 66 and the internal heat exchanger 76 and can be fluidly connected to the external heat exchanger 66 and the internal heat exchanger 76. The second expansion device 74 can have a similar configuration to the first expansion device 64 and can be configured to change the pressure of the refrigerant similar to the first expansion device 64. In addition, the second expansion device 74 can be closed to prevent the flow of the refrigerant. More specifically, in the heating mode, the second expansion device 74 can be closed to prevent the refrigerant from flowing from the external heat exchanger 66 to the internal heat exchanger 76. Therefore, closing the second expansion device 74 can prevent the refrigerant from flowing through the second control valve 68 to the internal heat exchanger 78 (if provided) and flowing through the internal heat exchanger 76.

[0034] The internal heat exchanger 76 may be fluidly connected to the second expansion device 74. The internal heat exchanger 76 may be disposed inside the passenger compartment 20. In a cooling mode or air conditioning environment, the internal heat exchanger 76 may function as an evaporator and may receive heat from the air in the passenger compartment 20 to evaporate the refrigerant. The refrigerant exiting the internal heat exchanger 76 may be directed to the accumulator 72. In a heating mode, the refrigerant may not be directed to the internal heat exchanger 76 due to the closure of the second expansion device 74.

[0035] The internal heat exchanger 78, if provided, can transfer thermal energy between refrigerant flowing through different areas of the heat pump subsystem 32. The internal heat exchanger 78 can be disposed outside of the passenger compartment 20. In a cooling mode or air conditioning environment, heat can be transferred from refrigerant directed from the external heat exchanger 66 to the internal heat exchanger 76 to refrigerant directed from the accumulator 72 to the pump 60. In a heating mode, the internal heat exchanger 78 does not transfer thermal energy between these refrigerant flow paths because the second expansion device 74 is closed, thereby preventing refrigerant from flowing through a portion of the internal heat exchanger 78.

[0036] In the series dehumidification mode, the VCHP subsystem operates similarly to the heating mode except that the third control valve 70 is closed and the second expansion device 74 allows coolant flow. In the parallel dehumidification mode, the VCHP subsystem operates similarly to the heating mode except that the first control valve 62 is open and the second expansion device 74 allows coolant flow.

[0037] In the de-ice mode, the VCHP subsystem operates similar to the heating mode, although the first expansion device 64 may be throttled or may be unthrottled (if an EXV) or bypassed (if a FOT or TXV) with the second expansion device 74 closed.

[0038] The ventilation subsystem 34 may circulate air within the passenger compartment 20 of the vehicle 10. The ventilation subsystem 34 may have a housing 90, a blower 92, and a temperature door 94.

[0039] Housing 90 may house components of ventilation subsystem 34. Figure 1 In the figure, for the sake of clarity, the housing 90 is shown so that the internal components are visible rather than hidden. In addition, the airflow through the housing 90 and the internal components is represented by the line with arrows. The housing 90 can be at least partially arranged in the passenger compartment 20. For example, the housing 90 or a part of the housing 90 can be arranged under the dashboard of the vehicle 10. The housing 90 can have an air intake 100, which can receive air from the outside of the vehicle 10 and / or from the inside of the passenger compartment 20. For example, the air intake 100 can receive ambient air from the outside of the vehicle 10 via an air intake channel, a duct or an opening, and the air intake channel, duct or opening can be located in any suitable position, such as near the front panel, wheel well or other body panels. The air intake 100 can also receive air from the inside of the passenger compartment 20 and recirculate such air through the ventilation subsystem 34. One or more doors or shutters can be provided to allow or prevent air recirculation.

[0040] The blower 92 may be disposed in the housing 90 . The blower 92 (which may also be referred to as a blower fan) may be disposed near the air intake 100 and may be configured as a centrifugal fan that may circulate air through the ventilation subsystem 34 .

[0041] A temperature door 94 may be disposed between the internal heat exchanger 76 and the heater core 44. In the illustrated embodiment, the temperature door 94 is disposed downstream of the internal heat exchanger 76 and upstream of the heater core 44. The temperature door 94 may block or allow airflow through the heater core 44 to help control the temperature of the air in the passenger compartment 20. For example, in a heating mode, the temperature door 94 may allow airflow through the heater core 44 so that heat may be transferred from the coolant to the air passing through the heater core 44. This heated air may then be provided to an air chamber for distribution to ducts and vents or outlets located in the passenger compartment 20. The temperature door 94 may be moved between a plurality of positions to provide air having a desired temperature. Figure 1 , temperature door 94 is shown in a full-heat position in which airflow is directed through heater core 44 .

[0042] The climate control system described above can help reduce the energy cost of the heat provided by supplementing the heat provided by the engine or vehicle power source. More specifically, the heat pump subsystem can generate additional heat and provide the additional heat to the coolant that can be used to heat the passenger compartment of the vehicle. In addition, the climate control system can promote the commonality of climate control system components (such as heater core and / or ventilation system designs). Therefore, a common heater core and / or ventilation system can be provided for vehicles with different powertrain configurations (such as models with internal combustion engines and hybrid electric powertrain options). This commonality can significantly reduce the associated processing and manufacturing costs by providing a common component design between different vehicle models (providing multiple powertrain configurations) and / or between different vehicle platforms.

[0043] Figure 3 250 is a table showing an example of component states during various operating modes of the VCHP subsystem. In this example, component states for a VCHP subsystem including an EXV are shown, however, it should be understood that as described below with respect to Figure 5 As further described, the table showing component states for a VCHP subsystem including a FOT or TXV will be modified to account for different expansion device assemblies (such as Figure 2A and 2B2 (as shown in FIG. 2 ). Hardware components are identified in column 252, and the operating mode is identified in operating mode column 254. For example, pump 60 is represented in row 256, second coolant pump 54 is represented in row 258, first expansion device 64 is represented in row 262, second expansion device 74 is represented in row 260, first control valve 62 is represented in row 266, and third control valve 70 is represented in row 264. Operating mode column 254 is further divided into a plurality of columns including cooling mode column 270, heating mode column 272, series dehumidification mode column 274, parallel dehumidification mode column 276, and de-icing mode column 278. As described above, table 250 can be used to identify component states during the operating mode of the VCHP subsystem. For example, during the heating mode, pump 60 is on, second coolant pump 54 is on, first expansion device 64 is throttled, second expansion device 74 is closed, first control valve 62 is closed, and third control valve 70 is open.

[0044] Figure 4 An example of a control strategy for a VCHP subsystem is shown, generally referred to herein as control strategy 300. Operation 304 represents a decision node in control strategy 300. In operation 304, the controller checks a comparison of the actual heater core temperature to the requested heater core temperature to identify whether to transition to operation 306, operation 308, or operation 310. Operations 306, 308, and 310 relate to heater core temperature conditions and the relationship between the requested heater core temperature and the actual heater core temperature. The system may remain at operation 306, operation 308, or operation 310 for a predetermined amount of time, or indefinitely, or until a predetermined condition occurs. For example, if the actual heater core temperature is less than the heater core temperature request, the heater core is operated in a cold mode in operation 306. If the actual heater core temperature is greater than or equal to the heater core temperature request, the heater core is operated in a warm mode in operation 308. If the actual heater core temperature is greater than or equal to the heater core temperature request plus a predetermined hysteresis (such as the second hysteresis described below), the heater core is operated in the hot mode in operation 310. The controller will continue to monitor the relationship between the actual heater core temperature and the heater core temperature request and direct appropriate transitions between operations 306, 308, and 310. The resulting state (e.g., cold, warm, or hot) is used in the control strategy to command the desired system mode, as further described below and in Figure 5 The desired system mode is used to determine commands for the various actuators or valves of the system.

[0045] Figure 5An example of a table used with a control strategy for a VCHP subsystem including an expansion device is shown, generally referred to as table 354. In one example, table 354 can be accessed via a controller that directs the operation of the VCHP subsystem. The commands included in table 354 assist in directing the operation of the heat pump mode and auxiliary heat source to identify effective operation based on hardware conditions and environmental conditions. In this example, T1 and T2 can be calibrated constants. For example, T1 can be approximately negative ten degrees Celsius and T2 can be approximately zero degrees Celsius. Table 354 includes a case type column 358, a climate cooling request column 360, a climate heating request column 362, a heater core coolant temperature status (hct_stat) column 364, and a column group 368 indicating various VCHP mode commands. Column group 368 is divided into three columns based on thermal conditions. Column 368A includes commands for situations where the ambient temperature (AAT) is less than T1. Column 368B includes commands for situations where T1 is less than or equal to AAT and AAT is less than T2. Column 368C includes commands for situations where AAT is greater than or equal to T2. A "*" is included to indicate situations where an auxiliary heat source may be operated to achieve the desired thermal conditions based on whether the heat pump can meet the amount of heat required.

[0046] In the climate cooling request column 360 of table 354, "0" indicates no cooling request, "1" indicates an opportunistic cooling request, "2" indicates a rapid cooling request, and "3" indicates a defrost / defog request. The case type column 358 may indicate a request from another system, a manual user input, or an automatic mode. In the climate heating request column 362 of table 354, "0" indicates no heating request, "1" indicates an opportunistic heating request, "2" indicates a rapid heating request, and "3" indicates a defrost / defog request.

[0047] The hct_stat column 364 represents the results from a state machine such as the control strategy 300 and describes the relationship of the heater core coolant temperature to the target heater core coolant temperature. For example, when the heater core coolant temperature is measured to be less than the target heater core coolant temperature, the hct_stat column 364 indicates COLD. When the heater core coolant temperature is measured to be greater than the target heater core coolant temperature but less than the sum of the target heater core coolant temperature and the first hysteresis, the hct_stat column 364 indicates WARM. When the heater core coolant temperature is measured to be greater than the sum of the target heater core coolant temperature and the second hysteresis, the hct_stat column 364 indicates HOT.

[0048] The VCHP modes represented by VCHP mode columns 368A, 368B, and 368C may be selected based on reference table 354. Table 354 may help determine the most efficient heat pump operating mode to achieve the desired vehicle operating conditions, thereby (for example) allowing the vehicle to operate at a lower energy state. If cooling and heating are requested simultaneously, the priority of cooling or heating will be determined based on ambient conditions to improve the efficiency of the heat pump subsystem 32 and also improve electric driving range. In certain circumstances, the auxiliary heat source 49 or power source 12 may be operated in place of the heat pump to provide supplemental heat to the system.

[0049] In another example, if the ambient temperature is measured to be below a predetermined threshold, it may be more efficient to operate the heat pump in a heating mode until hct_stat is WARM, and then provide vehicle dehumidification by operating the heat pump in a cooling mode and using an auxiliary heat source (such as a PTC heater) to heat the coolant. Operating in this manner can also speed up the amount of time required to make vehicle occupants feel comfortable. In yet another example, if the ambient temperature is measured to be greater than a predetermined threshold, the heat pump will be directed to operate in a cooling mode and use an auxiliary heat source to heat the coolant.

[0050] Figure 6 An example of an algorithm for operation of a VCHP subsystem is shown. The algorithm is generally represented by reference numeral 500. In operation 502, one or more sensors may measure an ambient temperature, and a controller may monitor a vehicle condition (such as a thermal condition) via a vehicle sensor. One or more sensors may send a signal to the controller including information related to the measured condition. Examples of vehicle conditions include an actual heater core coolant temperature, a target heater core coolant temperature, an occurrence of a climate control heating request, and an occurrence of a climate control cooling request. In operation 506, the controller may access a table (such as table 354) including operating directions for a heat pump and an auxiliary heat source. As described above, examples of auxiliary heat sources include a PTC heater and an engine. In operation 510, the controller may direct the operation of a heat pump and / or an auxiliary heat source based on the table to affect the efficiency of vehicle thermal management.

[0051] Although exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms covered by the claims. The words used in the specification are descriptive rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously mentioned, the features of each embodiment can be combined to form further embodiments of the present disclosure that may not be clearly described or illustrated. Although each embodiment has been described as providing advantages or being superior to other embodiments or prior art implementations in terms of one or more desired characteristics, it is recognized by those of ordinary skill in the art that, according to specific applications and implementations, one or more features or characteristics can be compromised to achieve the desired overall system properties. These properties may include, but are not limited to, marketability, appearance, consistency, robustness, customer acceptability, reliability, accuracy, etc. Therefore, embodiments described as being less desirable than other embodiments or prior art implementations in terms of one or more characteristics are not outside the scope of the present disclosure, and can be expected to be used for specific applications.

Claims

1. A vehicle climate control system for an electrified vehicle, comprising: a thermal circuit including a vapor compression heat pump and a positive temperature coefficient heater operating in a cooling mode and a heating mode; A controller configured to perform the following operations based on a heat source mode table in which cooling and heating are prioritized based on detected ambient conditions to increase an electric driving range of the vehicle: In response to receiving a request for simultaneous cooling and heating and detecting a system configuration that permits flow through the expansion device, directing operation of the vapor compression heat pump and the positive temperature coefficient heater, and In response to the heater core coolant being identified as warm and the ambient temperature being greater than a predetermined threshold, the controller requests the vapor compression heat pump to operate in a dehumidification mode based on the heat source mode table and requests the positive temperature coefficient heater to be deactivated.

2. The vehicle climate control system of claim 1, wherein: In simultaneous cooling and heating operation, when the heater core coolant is identified as warm and the ambient temperature is greater than a predetermined threshold, the controller requests the vapor compression heat pump to operate in a cooling mode and the positive temperature coefficient heater to operate in a heating mode based on the heat source mode table.

3. The vehicle climate control system of claim 1, wherein: In simultaneous cooling and heating operation, when the heater core coolant is identified as hot and the ambient temperature is greater than a predetermined threshold, the controller requests the vapor compression heat pump to operate in a cooling mode and requests the positive temperature coefficient heater to be deactivated based on the heat source mode table.

4. The vehicle climate control system of claim 1, wherein: In the simultaneous cooling and heating operation, when the heater core coolant is identified as warm and the ambient temperature is less than or equal to a predetermined threshold, the controller requests the positive temperature coefficient heater to output heat based on the heat source mode table.

5. The vehicle climate control system of claim 1, wherein: The simultaneous cooling and heating operation is also based on the relationship between the heater core coolant temperature and the target heater core coolant temperature, as well as the climate heating request, the climate cooling request, and the ambient temperature.

6. The vehicle climate control system of claim 1, wherein: The temperature of the heater core coolant is measured by a sensor and entered into the heat source mode table as one of cold, warm, and hot based on a calibratable constant.

7. The vehicle climate control system of claim 1, wherein: The expansion device is one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve, and during the cooling mode, an operating state of the fixed orifice expansion device, the thermal expansion valve, or the electronic expansion valve is enabled.

8. The vehicle climate control system of claim 1, wherein: The expansion device is one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve, and during the heating mode, an operating state of the fixed orifice expansion device, the thermal expansion valve, or the electronic expansion valve is not enabled.

9. The vehicle climate control system of claim 1, wherein: The expansion device is one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve, and the vehicle climate control system also includes another fixed orifice expansion device, a thermal expansion valve, or an electronic expansion valve, wherein, during a dehumidification mode, an operating state of the fixed orifice expansion device, the thermal expansion valve, or the electronic expansion valve is enabled for the expansion device for cooling, and an operating state of the other fixed orifice expansion device, the thermal expansion valve, or the electronic expansion valve is enabled for the expansion device for heating.

10. The vehicle climate control system of claim 1, wherein: The operation of the vapor compression heat pump and the positive temperature coefficient heater is based on predetermined temperature thresholds and the measured ambient temperature.

11. A vehicle climate control system for an electrified vehicle, comprising: a thermal circuit including an expansion device, a vapor compression heat pump operating in a cooling mode and a heating mode, and an auxiliary heat source; a controller configured to: enable the auxiliary heat source based on an operating state of the expansion device and a mode command table in which cooling and heating are prioritized based on detected ambient conditions to increase an electric driving range of the vehicle, Wherein, the auxiliary heat source is a positive temperature coefficient heater, and Wherein, when the heater core coolant is identified as warm and the ambient temperature is greater than a predetermined threshold, the controller requests the vapor compression heat pump to operate in a dehumidification mode based on the mode command table and requests the positive temperature coefficient heater to be deactivated.

12. The vehicle climate control system of claim 11, wherein: The expansion device is one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve, and during the heating mode, when the auxiliary heat source is activated, the fixed orifice expansion device, the thermal expansion valve, or the electronic expansion valve is directed to operate to be activated.

13. A method for operating a vehicle climate control system, comprising: In response to receiving both a cooling mode request and a heating mode request, outputting via the controller a command to enable an auxiliary heat source based on the ambient temperature and a predetermined calibratable constant temperature, and In response to the heater core coolant being identified as warm and the ambient temperature being greater than a predetermined threshold, the vapor compression heat pump is requested, via the controller, to operate in a dehumidification mode and the positive temperature coefficient heater is requested to be deactivated.

14. The method according to claim 13, further comprising: In response to detecting a change in flow of the expansion device, a vapor compression heat pump operating command is output via a controller to adjust the vehicle climate based on the ambient temperature, the heater core coolant temperature, the target heater core coolant temperature, and the climate control request.

15. The method according to claim 13, wherein: The auxiliary heat source is one of a positive temperature coefficient heater and an engine.

16. The method according to claim 14, wherein: The expansion device is one of a fixed orifice expansion device, a thermal expansion valve, and an electronic expansion valve.

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