VEHICLE WITH A CONTROL UNIT FOR THE THERMAL SYSTEM OF A VEHICLE

Abstract

Vehicle, including: a passenger compartment; A thermal energy management system (12) comprising a first and a second thermofluid circuit (14), wherein the first thermofluid circuit (14) includes a coolant pump (26) configured to circulate a coolant (28) through a power electronics module (34), an electric motor (40), a coolant heater (30), a chiller (50), and a vehicle battery (38) in the specified order, such that the first thermofluid circuit (14) is configured to selectively transfer thermal energy between the vehicle battery (38) and the chiller (50), and the second thermofluid circuit (14) is configured to circulate a refrigerant (74) through at least the chiller (50), a compressor (80), an evaporator (94), and an external condenser (90), such that the second thermofluid circuit (14) is configured to transfer thermal energy between the chiller (50) and the external condenser. (90) transfers,wherein the second thermofluid circuit (14) downstream of the compressor (80) further comprises a passenger compartment condenser (86) connected in parallel with the external condenser (90) for the transfer of thermal energy into the passenger compartment; and , a controller (16) configured to control the thermal energy management system (12) according to a passenger compartment cooling mode for cooling the passenger compartment and a battery cooling mode for cooling the vehicle battery (38); wherein the external condenser (90) is configured to transfer thermal energy from the second thermofluid circuit (14) directly to the ambient air.

Description

INTRODUCTION

[0001] The present invention relates to a vehicle with a thermal management system for controlling the operation of sources and sinks of thermal energy within a motor vehicle.

[0002] DE 11 2013 001 769 T5, for example, describes a vehicle with a first and a second thermofluid circuit, wherein the first thermofluid circuit contains a coolant pump by means of which a coolant is circulated through a vehicle battery. The second thermofluid circuit is thermally coupled to the first thermofluid circuit via a heat exchanger, and its compressor circulates a refrigerant through a condenser to transfer thermal energy between the heat exchanger and the condenser.

[0003] Further state of the art can also be found in publications WO 2021 / 259 513 A1, WO 2021 / 009 309 A1 and US 2019 / 0 070 924 A1, although the two WO publications were not yet known on the relevant priority date.

[0004] Emissions standards, environmental concerns, and driver perception regarding responsiveness, smoothness, noise, vibration, and harshness (NVH), as well as driver comfort, dictate many of the ways in which thermal energy is managed within a motor vehicle. Traditionally, efforts have focused on maximizing efficiency within the limitations of internal combustion engines (ICEs) used as propulsion units for motor vehicles. Such advances have generally taken the form of improving combustion efficiency (maximizing the conversion of combustion energy into motive power), recovering or utilizing thermal combustion energy to operate heating, ventilation, and air conditioning (HVAC) systems, recovering kinetic energy during braking to charge the battery, and similar approaches.The recovery functions are often implemented in dedicated heating, cooling, or electrical circuits, resulting in a relatively complex series of circuits, many of which operate almost completely independently of each other.

[0005] Although internal combustion engines have become increasingly efficient and are likely to continue to do so, they still generate significant amounts of thermal energy, a substantial portion of which is typically released into the vehicle's environment. In other words, a vehicle with an internal combustion engine produces excess thermal energy that cannot be effectively or efficiently retained within the vehicle. Consequently, a significant amount of so-called "high-quality" thermal energy is often released from the vehicle into the atmosphere.In an effort to mitigate the inefficient use of internal combustion engines, reduce emissions and environmental impact, and improve responsiveness, smoothness, NVH (noise, vibration, and harshness), and driver comfort, motor vehicles are increasingly relying on electric power for both propulsion and passenger compartment management. However, the growing use of electric power, as generated by innovative drive systems such as hybrid systems, batteries, fuel cells, and the like, has drastically reduced the quantity and quality of thermal energy produced by vehicles with such innovative drive systems.

[0006] Accordingly, while conventional thermal management systems and methods originally developed for internal combustion engines can be applied to innovative propulsion systems such as battery electric vehicles (BEVs)—which rely primarily on a battery and an electric motor-generator for propulsion—the excess thermal energy is much lower than in an internal combustion engine. Therefore, while conventional thermal management systems and methods can serve their purpose in internal combustion engines, there is a need for improved thermal management systems and methods for vehicles in which the use of internal combustion engines is reduced and / or eliminated entirely.Therefore, there is a need for new and improved thermal management systems and procedures that efficiently collect, store and distribute thermal energy to vehicle systems that require this energy, while simultaneously reducing hardware costs and complexity, improving reliability, and providing enhanced safety and redundancy as well as reduced range anxiety for vehicle operators. SUMMARY

[0007] A vehicle according to the present invention is characterized by the features of claim 1 and comprises a passenger compartment, a thermal energy management system, and a controller. The thermal energy management system has a first and a second thermofluid circuit. The first thermofluid circuit comprises a coolant pump configured to circulate a coolant through at least one vehicle battery and a chiller, such that the first thermofluid circuit is configured to selectively transfer thermal energy between the vehicle battery and the chiller. The second thermofluid circuit is configured to circulate a refrigerant through at least one chiller, a compressor, and at least one condenser, such that the second thermofluid circuit is configured to transfer thermal energy between the chiller and the condenser.The second thermofluid circuit, downstream of the compressor, further comprises a passenger compartment condenser connected in parallel with the condenser for transferring thermal energy into the passenger compartment. The controller is configured to manage the thermal energy system according to a passenger compartment cooling mode for cooling the passenger compartment and a battery cooling mode for cooling the battery. The condenser is configured to transfer thermal energy from the second thermofluid circuit directly to the ambient air. In passenger compartment cooling mode, the compressor operates at a first power setting. In an exemplary embodiment, in battery cooling mode, the compressor operates at a second power setting, and the chiller is controlled to transfer thermal energy from the first thermofluid circuit to the second thermofluid circuit.The second power setting is lower than the first power setting.

[0008] In one exemplary embodiment, the second power setting is a setting for minimum operating power for the compressor.

[0009] In one exemplary embodiment, the external condenser can be operated with a first airflow rate and a second airflow rate. The second airflow rate is greater than the first airflow rate. In battery cooling mode, the condenser is operated with the second airflow rate. In such embodiments, the second airflow rate can be a maximum passive airflow rate for the condenser.

[0010] In an exemplary embodiment, the thermofluid in the condenser is kept in a subcritical state during the second power setting.

[0011] Embodiments according to the present invention offer a number of advantages. For example, thermal management systems according to the present invention can have lower complexity, lower costs and lower mass (and thus a greater range) compared to known solutions.

[0012] The above advantage and other advantages and features of the present invention will be evident from the following detailed description of the preferred embodiments when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic representation of a vehicle according to an embodiment of the present invention; Fig. Figure 2 is a schematic representation of a thermal management system according to an embodiment of the present invention; and Fig. 3A and Fig. Figure 3B shows flowchart representations of a method for controlling a thermal management system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0013] In Fig. Figure 1 represents a motor vehicle and is generally designated by the reference number 10. While the motor vehicle 10 is represented as a passenger car, it could be a passenger car, a truck, an off-road vehicle, a van, a semi-trailer truck, a tractor, a bus, a go-kart, or any other such motor vehicle 10. The motor vehicle 10 is equipped with a thermal management system 12, referred to here simply as the management system 12. In general terms, the thermal management system 12 operates by selectively transporting thermal energy from a heat source within the thermal management system 12 to a heat sink within the thermal management system 12, or from a heat source or a heat sink to a location within the thermal management system 12 where the thermal energy is desired. The thermal management system 12 comprises a variety of different thermofluid circuits 14 for various subsystems of the motor vehicle 10.Each of the different thermofluid circuits 14 has heat sources and heat sinks connected to one or more of the vehicle subsystems 10. However, some heat sinks are significantly larger and can therefore store more thermal energy than others. Accordingly, depending on the thermal energy storage capacities of different heat sinks within the thermal management system 12, thermal energy can be transferred from one of the different thermofluid circuits 14 to another.

[0014] As already mentioned, the motor vehicle can circulate or transfer thermal energy via a reduced number of thermofluid circuits compared to previous approaches. In the Fig. In the example shown, the motor vehicle 10 circulates the thermal energy generated on board the vehicle only via the two thermofluid circuits 14. In other words, the thermal requirements of the motor vehicle 10, i.e., the need for heating or cooling components of the motor vehicle 10 as well as for heating or cooling the passenger compartment, can be met by using only the two thermofluid circuits 14. The thermal energy can be transferred via the thermofluid circuits 14 by conduction, convection, or any other suitable heat transfer mechanism.

[0015] A controller 16, which is electronically connected to a variety of actuators, valves, and the like, controls the operation of the thermal management system 12, including the variety of different thermofluid circuits 14. The controller 16 is a non-generalized electronic control device with a pre-programmed digital computer or processor 18, a memory or non-transient, computer-readable medium 20 for storing data such as control logic, instructions, lookup tables, etc., and a variety of input / output peripherals or ports 22. The processor 18 is configured to execute the control logic or instructions. The controller 16 may have additional processors or additional integrated circuits that communicate with the processor 18, such as logic circuits for analyzing thermal management data.In some examples, the controller 16 can be better described as a plurality of controllers 16, each designed to interact with and manage specific components within the motor vehicle 10, and each of the plurality of controllers 16 is in electronic communication with the others. Although more than one controller 16 may be used in some examples, the following description focuses, for the sake of clarity, on a thermal management system 12 with only a single controller 16.

[0016] Referring to Fig. 2 and with further reference to Fig. 1 is a first of the different thermofluid circuits 14, a coolant circuit 24. The coolant circuit 24 comprises a coolant pump 26, which is arranged to selectively pump coolant 28 from a coolant filling bottle 39 through a plurality of coolant lines 32. The coolant lines 32 are in fluid communication with various components of the coolant circuit 24. In the illustrated embodiment, the components of the coolant circuit 24 include an integrated power electronics module 34. The power electronics module 34 is an electronic device with a plurality of accessories that can be used by the vehicle operator. In the illustrated embodiment, the power electronics module 34 comprises an inverter / converter module 31, an accessory power module 33, and an onboard charging module (OBCM) 36.Other embodiments within the scope of the present invention may include one or more additional accessories instead of those specified in . Fig. 2 shown or included in addition to these. When the power electronics module 34 is operated, the electronics within the power electronics module 34 convert electrical energy into a variety of functions that can be used by the vehicle and / or the operator. Additionally, thermal energy is generated as a byproduct of the use of electrical energy within the power electronics module 34. The coolant 28 carries the thermal energy from the power electronics module 34 to other locations in the coolant circuit 24.

[0017] As discussed below, the thermal energy of the power electronics module 34 may not exhibit significant power output and, in this sense, may be relatively "inferior" compared to sources such as an internal combustion engine. However, as described below, the thermal energy management system 12 can facilitate the accumulation of such inferior thermal energy so that it can subsequently be used in the passenger compartment or elsewhere in the vehicle 10 in a manner consistent with previous approaches that utilize "high-quality" thermal energy sources such as internal combustion engines. Thus, the thermal energy management system 12 can still provide sufficient heating power despite the absence of an internal combustion engine in the vehicle 10.

[0018] The OBCM 36 is electrically coupled to a high-voltage battery 38, also referred to here as battery 38. The OBCM 36 is an electrical device that serves to transfer energy to a secondary cell or rechargeable battery 38 by forcing an electric current through the battery 38. In some examples, a single-phase OBCM 36 with a power output of 3.5 kW to 22 kW is installed in the electrical system of the motor vehicle 10 and charges the motor vehicle 10's battery 38 from a power grid. In other examples, the motor vehicle 10's battery 38 can be used as a power source, and therefore the OBCM 36 can also transfer electrical energy to the power grid or to accessories or auxiliary equipment within the motor vehicle 10.Furthermore, the OBCM 36 can also supply electrical energy to devices such as mobile phones and the like, which an operator of the motor vehicle 10 can power via electrical connections within the power electronics module 34 of the motor vehicle 10. In some cases, the OBCM 36 is therefore a bidirectional device for charging and discharging the battery 38.

[0019] In many cases, battery 38 is charged most efficiently when it is heated to a predetermined setpoint temperature. In one instance, the predetermined setpoint temperature is approximately 25° Celsius. However, depending on the configuration and thermal requirements of the components of the thermal management system 12, the predetermined setpoint temperature of battery 38 can vary. In one example, to reach the setpoint temperature, battery 38 can be heated electrically using the electrical energy supplied by the OBCM 36. In this example, the controller 16 effectively overrides the OBCM 36 or controls the OBCM 36 in a deliberately inefficient manner to convert a predetermined amount of electrical energy into thermal energy, for example, to increase the temperature of battery 38. In another example, battery 38 itself is charged in a deliberately inefficient manner.This means that the battery 38 is charged inefficiently, so that some of the electrical energy driven into the battery 38 by the OBCM 36 is converted into thermal energy, which is then stored in the mass of the battery 38 while the battery 38 is being charged. In another example, thermal energy from other heat sources inside and outside the coolant circuit 24 is transferred to the battery 38 via the coolant 28 carried by the coolant circuit 24. In the illustrated embodiment of the invention, the coolant circuit 24 includes a coolant heater 30. The coolant heater 30 is an electrically operated heater that adds thermal energy to the coolant 28 and thereby helps to bring the battery 38 to an optimal charging temperature. In some examples, after the battery 38 has been sufficiently charged electrically and with sufficient thermal energy, the temperature of the battery 38 is regulated by the OBCM 36.

[0020] The battery 38 is electrically coupled to an electric motor 40. The electric motor 40 is configured to selectively deliver drive torque to the vehicle wheels, for example, via a transmission. When delivering drive torque, the energy stored in the battery 38 is supplied to the electric motor 40 and converted into drive torque. In some embodiments of motor vehicles 10 with regenerative braking systems, the electric motor 40 is also used as an electric generator. If the controller 16 and the OBCM 36 determine that the battery 38 is fully charged or if additional heating is otherwise required, the electricity generated by the electric motor 40 can be converted into thermal energy and stored in the mass of the battery 38 or other components of the thermal management system 12.

[0021] The coolant circuit 24 additionally directs the coolant 28 through a chiller 50, which is arranged in the second of the different thermofluid circuits 14, in particular a refrigerant circuit 52. The chiller 50 is a heat exchanger that provides a means for the transfer of thermal energy between the coolant circuit 24 and the refrigerant circuit 52. The chiller 50 comprises at least two spatially separated passages. That is, on a first side of the chiller 50, a coolant passage (not shown) carries coolant 28 through the chiller 50 as part of the coolant circuit 24. On a second side of the chiller 50, a refrigerant passage (not shown) carries a refrigerant 74 through the chiller 50 as part of the refrigerant circuit 52.However, it should be understood that despite the fact that the chiller 50 contains part of both the coolant circuit 24 and the refrigerant circuit 52, there is no liquid interface between coolant 28 and refrigerant 74 within the chiller 50, thus preventing a mixing of coolant 28 and refrigerant 74.

[0022] The refrigerant circuit 52 comprises a multitude of refrigerant lines 76 that fluidically connect a multitude of devices for the thermal regulation of a passenger compartment (not specifically shown) in the motor vehicle 10. The passenger compartment may be thermally insulated from other heat-generating vehicle components and may be supplied with thermal energy via one or more vents or other lines (not specifically shown) of the HVAC system 78. The refrigerant circuit 52 also transports thermal energy to and from the coolant circuit 24 via the chiller 50. The refrigerant circuit 52 includes a multitude of operator comfort systems, such as a heating, ventilation, and air conditioning (HVAC) system 78. Essentially, the refrigerant circuit 52 has a heating function and a cooling function. Within the refrigerant circuit 52, the HVAC system 78 supplies a passenger compartment of the motor vehicle 10 with heated and / or cooled air.In other words, the HVAC system 78 transports thermal energy from a cooler location to a warmer location within the refrigerant circuit 52. In several respects, the HVAC system 78 functions as a heat pump. That is to say, the HVAC system 78 is an air conditioning unit capable of both heating and cooling functions.

[0023] In an exemplary operating mode, the operator of the motor vehicle 10 determines a desired passenger compartment air temperature and selects a heating cycle for the HVAC system 78. The HVAC system 78 contains a compressor 80. The refrigerant 74 enters the compressor 80 via a refrigerant line 76, the so-called suction line. The compressor 80 compresses the gaseous refrigerant 74, thereby increasing its temperature and pressure. The refrigerant 74, now under high pressure and high temperature, then leaves the compressor 80 via a refrigerant line 76, referred to as the pressure line 84, and flows into a passenger compartment condenser 86. In some aspects, the passenger compartment condenser 86 is a heat exchanger with a multitude of condenser coils through which the refrigerant 74 flows. The coils are in contact with the passenger compartment atmosphere.An HVAC blower or fan (not shown) blows air over the passenger compartment condenser 86, thereby transferring thermal energy from the passenger compartment condenser 86 to the passenger compartment atmosphere. In some aspects, the refrigerant circuit 52 includes a second or external condenser 90. The external condenser 90 is in contact with the atmosphere outside the vehicle 10 and, when switched on, transfers thermal energy from the refrigerant 74 from the vehicle 10 to the atmosphere.

[0024] The HVAC system 78 also includes a variety of expansion valves 92. Depending on the design parameters of the HVAC system 78, the expansion valves 92 can be mechanical thermostatic expansion valves (TXV) (not shown) and / or electronic expansion valves (EXV) (not shown). The expansion rate of the refrigerant 74 can be controlled more directly and precisely with EXVs than with TXVs; however, in some cases it is desirable to use TXVs for reasons of cost, simplicity, etc. The condensed, pressurized, and still somewhat warm refrigerant 74 from the passenger compartment condenser 86 and / or external condenser 90 is passed through an expansion valve 92. As the refrigerant 74 is depressurized by the expansion valve 92, it cools down. The refrigerant 74 then passes through an evaporator 94.The evaporator 94 is a heat exchanger in which a series of cooling coils (not shown) carry a flow of chilled refrigerant 74. The cooling coils exchange thermal energy with the passenger compartment atmosphere. The HVAC blower or fan blows air over the evaporator 94, thereby cooling the passenger compartment of the vehicle 10. After passing through the evaporator 94, the refrigerant 74 is returned to the compressor 80. The refrigerant 74 is also selectively routed through an expansion valve 92 downstream of the chiller 50, where thermal energy is either extracted from or supplied to the coolant circuit 24, depending on the relative temperatures of the coolant 28 and the refrigerant 74 and the thermal requirements of the battery 38 and other components of the thermal management system 12.

[0025] In one example, the HVAC system 78 can be operated intermittently or continuously by the occupants in the passenger compartment or by the controller 16, depending on the optimal heating and / or cooling requirements of the passenger compartment or the optimal heating and / or cooling requirements of other components of the thermal management system 12. In another example, the HVAC system 78 operates continuously as a heat pump. As mentioned earlier, when operating as a heat pump, the HVAC system 78 circulates the refrigerant 74 through the passenger compartment condenser 86, thereby transferring the thermal energy in the refrigerant 74 to the passenger compartment and cooling the refrigerant 74. While the refrigerant 74 releases thermal energy as it passes through the passenger compartment condenser 86 and the external condenser 90, thermal energy is gained as it passes through the chiller 50.Similarly, in a second example, the controller 16 directs the refrigerant 74 through the external condenser 90, where the refrigerant 74 is cooled by releasing thermal energy to the atmosphere, but since the refrigerant 74 also flows through the chiller 50, thermal energy is transferred and gained as the refrigerant 74 passes through the chiller 50.

[0026] Conventional vehicles with an internal combustion engine may contain one or more additional fluid circuits, e.g., a lubrication circuit for the internal combustion engine. However, in the illustrated embodiment of a battery-electric vehicle 10, no internal combustion engine is provided, and therefore no such circuits are present.

[0027] State-of-the-art thermal management systems incorporate a passive cooling mechanism into the coolant circuit 24. Such thermal management systems would, for example, include a radiator for exchanging thermal energy between the coolant 28 and the atmosphere outside the vehicle 10. While such passive cooling mechanisms can dissipate thermal energy from the vehicle 10, they also contribute to the weight and cost of the thermal management system.

[0028] As can be seen, the embodiments according to the present invention do without such a passive cooling mechanism. Instead, embodiments according to the present invention, as further below with reference to Fig. 3 is described in more detail, a novel control scheme to achieve high coefficient of performance (CoP) cooling via the refrigerant circuit without a passive cooling mechanism in the coolant circuit.

[0029] In Fig. Figure 3 now presents a method for controlling a thermal management system, e.g., thermal management system 12, in the form of a flowchart. In general terms, the controller 16 controls the functions of the coolant circuit 24 and the refrigerant circuit 52 via the chiller 50 to transfer thermal energy to devices within the motor vehicle 10 where the thermal energy is required.

[0030] The heat management procedure begins in block 100, where a continuous control loop of the heat management system 12 is initiated.

[0031] The procedure continues to block 102, where the controller 16 calculates a critical temperature for one or more components of the thermal management system 12. Such components can be the battery 38, the electric motor 40, the power electronics module 34, and other components in the thermal management system 12. The critical drive temperature refers to a temperature at which the measured temperature for a particular component exceeds the optimal range for that component and approaches a state of overheating. The calculation of the critical temperature can be based on a variety of factors, including, but not limited to, a temperature rise rate, vehicle loads, customer operating modes, and other factors. In some embodiments, the critical temperature can be defined such that, when exceeded, the controller 16 is configured to prioritize cooling over energy consumption.The controller 16 also determines the current temperature of one or more components, e.g. via thermal sensors attached to these components or other suitable means.

[0032] The procedure continues to operation 104, which determines whether the current temperature of one or more components of the thermal management system 12 is greater than the calculated critical temperature for that component.

[0033] If the determination of Operation 104 is negative, i.e., the current temperature does not exceed the critical temperature for any component of the thermal management system 12, the procedure proceeds to Operation 106, which determines whether the criteria for an opportunity cooling mode are met. Opportunity cooling refers to a mode in which the critical temperature is not currently exceeded, but a future cooling requirement is foreseeable and the conditions for cooling are present. The criteria for the opportunity cooling mode may include limits for the ambient temperature, the airflow at the front, the current temperatures of various components of the thermal management system 12, the estimated temperature based on the load, and lower and upper limits of the desired operating temperatures of the various components of the thermal management system 12.

[0034] If the determination of operation 106 is negative, i.e., the criteria for the opportunity cooling mode are not met, the controller 16 operates the thermal management system 12 according to a standard thermal operating mode, as shown in block 108. An example of such standard operation is described in jointly filed US patent application US 2020 / 0047586A1.

[0035] The process then returns to block 102, so the process is an endless loop.

[0036] In response to a positive determination of either Operation 104 or 106, meaning that the current temperature exceeds the critical temperature or that opportunity cooling is available, the procedure proceeds to Operation 110. In Operation 110, Controller 16 determines whether a passenger compartment heat change is currently being requested. A passenger compartment heat change refers to a request to heat or cool a passenger compartment. If Operation 110 is positive, the procedure proceeds to Block 108 as described above.

[0037] If the result of Operation 110 is negative, i.e., no change in passenger compartment temperature is requested, the procedure proceeds to Operation 112. In Operation 112, the controller determines whether the difference between the temperature of the coolant 28 at the chiller 50 inlet and the ambient temperature near the vehicle 10 exceeds a predefined threshold. The predefined threshold is a positive, non-zero value defined by a cost function based on the airflow at the front of the vehicle and calculated to ensure sufficient heat transfer between the coolant 28 and the ambient air near the vehicle 10. In an exemplary embodiment, the threshold can be set in the range of 7° to 10° C.

[0038] If the determination of Operation 112 is negative, the procedure continues with Block 108 as described above.

[0039] In response to the positive determination of operation 112, i.e., that the difference between the temperature of the refrigerant 28 at the inlet of the chiller 50 and the ambient temperature is at least equal to the predefined threshold, the refrigerant circuit is controlled according to an increased CoP mode, as shown in block 114. The increased CoP mode is described in Fig. 3B is described in more detail. The control then returns to block 102.

[0040] As in Fig.As shown in Figure 3B, in the increased CoP mode, the front airflow to the external condenser 90 is controlled to increase it, as shown in Block 114a. In one exemplary embodiment, this is achieved by controlling an aperture system that opens and increases the airflow to the external condenser 90. The aperture system can be fully opened to maximize the passive airflow to the external condenser 90. In some embodiments, a front fan connected to the external condenser 90 can also be activated to further increase the airflow by active means. In such embodiments, the fans can be controlled to a low power setting to minimize power consumption.

[0041] The controller 16 then controls the compressor 80 at a reduced power setting, as shown in block 114b. In one exemplary embodiment, at the reduced power setting, the refrigerant 74 is kept in a subcritical state, i.e., no liquid-to-gas phase transition occurs during compression. In another exemplary embodiment, the reduced power can be a minimum operating power of the compressor 80, i.e., the lowest non-zero power at which the compressor 80 is configured to operate.

[0042] Then the electronic expansion valve (EXV) for the chiller 50 is switched on to allow heat transfer between the coolant 28 and the refrigerant 74, as shown in block 114c.

[0043] An optimized superheat setpoint for the EXV is then calculated and updated, as shown in Block 114d. In one exemplary embodiment, the superheat setpoint is calculated based on a desired heat transfer between the coolant 28 and the refrigerant 74, e.g., using a cost function to determine a heat transfer rate to maximize the CoP. The controller can then actuate the EXV and set the valve setpoint to this calculated superheat setpoint.

[0044] The exemplary thermal energy management system 12 can advantageously transfer thermal energy between the two thermofluid circuits, as mentioned above. In this way, excess thermal energy from heat sources such as the vehicle battery 38 or other electronics can be released to the atmosphere via the refrigerant circuit 52 with relatively little energy expenditure. In contrast, previous approaches to vehicle heating would require a separate radiator within the coolant circuit 24. Compared to known solutions, embodiments according to the present invention are therefore less complex, less expensive, have a lower mass (and thus a greater range), and produce less noise and vibration.

Claims

[1] Vehicle, comprising: a passenger compartment; A thermal energy management system (12) comprising a first and a second thermofluid circuit (14), wherein the first thermofluid circuit (14) includes a coolant pump (26) configured to circulate a coolant (28) through a power electronics module (34), an electric motor (40), a coolant heater (30), a chiller (50), and a vehicle battery (38) in the specified order, such that the first thermofluid circuit (14) is configured to selectively transfer thermal energy between the vehicle battery (38) and the chiller (50), and the second thermofluid circuit (14) is configured to circulate a refrigerant (74) through at least the chiller (50), a compressor (80), an evaporator (94), and an external condenser (90), such that the second thermofluid circuit (14) is configured to transfer thermal energy between the chiller (50) and the external condenser. (90) transfers,wherein the second thermofluid circuit (14) downstream of the compressor (80) further comprises a passenger compartment condenser (86) connected in parallel with the external condenser (90) for the transfer of thermal energy into the passenger compartment; and, a controller (16) configured to control the thermal energy management system (12) according to a passenger compartment cooling mode for cooling the passenger compartment and a battery cooling mode for cooling the vehicle battery (38); wherein the external condenser (90) is configured to transfer thermal energy from the second thermofluid circuit (14) directly to the ambient air. [2] Vehicle according to claim 1, wherein in passenger compartment cooling mode the compressor (80) is operated with a first power setting and wherein in battery cooling mode the compressor (80) is operated with a second power setting and the chiller (50) is controlled such that it transfers thermal energy from the first thermofluid circuit (14) to the second thermofluid circuit (14), wherein the second power setting is lower than the first power setting. [3] Vehicle according to claim 1, wherein the second power setting is a setting of minimum operating power for the compressor (80). [4] Vehicle according to claim 1, wherein the external condenser (90) can be operated with a first airflow rate and a second airflow rate, wherein the second airflow rate is greater than the first airflow rate, and wherein the external condenser (90) is operated with the second airflow rate in battery cooling mode. [5] Vehicle according to claim 4, wherein the second airflow rate is a maximum passive airflow rate for the external condenser (90). [6] Vehicle according to claim 1, wherein the first thermofluid circuit (14) is a coolant circuit (24) and the second thermofluid circuit (14) is a refrigerant circuit (52). [7] Vehicle according to claim 1, wherein in the second power setting the thermofluid in the external condenser (90) is kept in a subcritical state.

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