Method and apparatus for determining a compressor energy cost for a thermal management system of an electric vehicle

Abstract

There is provided a method of determining a compressor energy cost associated with a compressor of a climate control system of an electric vehicle. The method comprises obtaining a plurality of compressor models, each compressor model associated with a respective one of the plurality of configurations of the climate control system, receiving an indication of a configuration of the climate control system, receiving an indication of an amount of transferable thermal energy associated with a powertrain of the electric vehicle, selecting a compressor model based on the indication of the configuration of the climate control system, determining a compressor energy cost associated with the compressor of the climate control system based on the transferable thermal energy value and the selected compressor model, and providing an output signal based on the compressor energy cost.

Description

[0001] METHOD AND APPARATUS FOR DETERMINING A COMPRESSOR ENERGY COST FOR A THERMAL MANAGEMENT SYSTEM OF AN ELECTRIC VEHICLE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method and apparatus for determining a compressor energy cost for a thermal management system of an electric vehicle. In particular, the present disclosure relates to a method and apparatus for determining compressor energy costs for a compressor in a climate control system of the thermal management system and based on an indication of an amount of transferable thermal energy associated with a power train of the electric vehicle. Aspects of the invention relate to a method, a computer readable medium, computer readable instructions, a control system and a vehicle.

[0004] BACKGROUND

[0005] A thermal management system of an electric vehicle may allow thermal energy to be transferred between components of the vehicle. Careful management of heat transfer between components of the vehicle may reduce the amount of electrical power that would otherwise be expended to power a resistive heater to provide thermal energy, or to reject thermal energy to the ambient environment. Thus, selecting an appropriate operating mode for the thermal management system may significantly reduce the amount of power used to manage the temperature of components of the vehicle, thereby improving range of the electric vehicle. However, it can be difficult to accurately determine the energy used by the thermal management system. One component of the vehicle thermal management system that may expend a significant amount of energy is a compressor forming part of a refrigerant circuit of a climate control system. However, when operating the compressor, a portion of the work expended is converted to thermal energy within the refrigerant. As such, it can be particularly difficult to predict the overall energy cost associated with operation of the compressor within the thermal management system.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide an method of determining an operating mode of a thermal management system of an electric vehicle, a computer program, a control system, and a vehicle as claimed in the appended claims.

[0009] According to an aspect of the present invention there is provided a method of determining a compressor energy cost associated with a compressor of a climate control system of an electric vehicle, the method comprising obtaining a compressor model associated with a configuration of the thermal management system and determining the compressor energy costs based on the obtained model and an indication of an amount of transferable energy associated with the powertrain of the vehicle. Advantageously, an accurate determination of an energy cost associated with operating a compressor in a refrigerant circuit of a climate control system can be made.

[0010] According to an aspect of the present invention, there is provided a method of determining a compressor energy cost associated with a compressor of a climate control system of an electric vehicle, the climate control system operable in a plurality of configurations, the method comprising obtaining a plurality of compressor models, each compressor model associated with a respective one of the plurality of configurations of the climate control system, receiving an indication of a configuration of the climate control system, receiving an indication of an amount of transferable thermal energy associated with a powertrain of the electric vehicle, selecting a compressor model based on the indication of the configuration of the climate control system, determining a compressor energy cost associated with the compressor of the climate control system based on the indicated amount of transferable thermal energy and the selected compressor model, and providing an output signal based on the compressor energy cost.

[0011] Advantageously, an accurate determination of an energy cost associated with operating a compressor in a refrigerant circuit of a climate control system can be made. In particular, different operating configurations of the climate control system, relating to different sources / sinks of thermal energy to be used, can be associated with different models of the compressor operation to allow an accurate determination to be made for each configuration. In embodiments, the transferable thermal energy associated with a powertrain of the electric vehicle comprises an amount of thermal energy that is available to be transferred from the powertrain of the electric vehicle to a refrigerant of the climate control system via a heat exchanger.

[0012] Optionally, each compressor model defines a relationship between operating parameters of the climate control system and an energy cost of operating the compressor.

[0013] Optionally, the output signal may be representative of the determined compressor energy cost.

[0014] In embodiments, receiving an indication of a configuration of climate control system comprises receiving an indication of a first configuration while the climate control system is operating in a second configuration, wherein the first configuration is different from the second configuration.

[0015] Advantageously, a compressor model can be selected that is for a configuration other than the current configuration in which the climate control system is operating. That is the compressor model can be applied for different operating configurations of the climate control system to generate a compressor energy cost value for the different target configurations.

[0016] Optionally, the determined compressor energy cost comprises a predicted compressor energy cost for the first configuration of the thermal management system while the climate control system is operating in a second configuration.

[0017] Advantageously, a compressor energy can be predicted for different configurations than the current configuration.

[0018] In embodiments, determining the compressor energy cost associated with the compressor comprises determining, for each configuration of the plurality of operating configurations of the climate control system, the compressor energy cost associated with the compressor when operating in the respective operating configuration, selecting an operating configuration for the climate control system based on the plurality of determined compressor energy costs, and wherein the output signal indicates the selected operating configuration.

[0019] Advantageously, compressor energy values for multiple different operating configurations of the climate control system can be determined and used to guide selection of a particular operating configuration that is at least in part based on the determined compressor energy costs, e.g. by selecting an operating configuration associated with a lower or lowest energy cost.

[0020] Optionally, the compressor energy cost is further determined based on a thermal energy demand associated with the climate control system.

[0021] A parameter that correlates strongly with the compressor energy cost in some operating configurations is a thermal energy demand associated with the climate control system, that is, an amount of thermal energy that is to be transferred to, or extracted from, the climate control system.

[0022] In embodiments, the method comprises, in response to the thermal energy demand having a magnitude less than a first threshold value, determining the compressor energy cost further based on an ambient temperature value.

[0023] Advantageously, in the case that the magnitude of the thermal energy demand is less than a threshold value, i.e. that the amount of energy to be transferred to, or extracted from the climate control system, is small, for example when the climate control system is switched off, then ambient temperature may be used to accurately determine the compressor energy cost for certain operating configurations.

[0024] In embodiments, the method comprises, in response to the indicated amount of transferable thermal energy having a magnitude less than a second threshold value, determining the compressor energy cost further based on an ambient temperature value.

[0025] Advantageously, in the case that the magnitude of the indicated amount of transferable thermal energy is less than a threshold value, i.e. that the amount of energy that may be transferred to, or extracted from the powertrain is small, then ambient temperature may be used to accurately determine the compressor energy cost for certain operating configurations. Optionally, the indicated amount of transferable thermal energy comprises an upper threshold amount of thermal energy that may be exchanged between the powertrain and the climate control system over a predetermined period of time.

[0026] Advantageously, the method is able to use an indication of an amount of thermal energy that may be exchanged between the powertrain and the climate control system over a predetermined period of time to allow for dynamic effects, for example by choosing to rely on thermal energy that is expected to be generated in a component of the powertrain in the near future to provide thermal energy to the climate control system, and determining the compressor energy cost on that basis.

[0027] Optionally, the electric vehicle powertrain comprises at least one of a traction battery and an electric drive unit.

[0028] Advantageously, thermal energy can be transferred between the CCS and a traction battery and / or electric drive units of the vehicle, thereby allowing excess thermal energy generated in those components to be used to heat a passenger compartment of the electric vehicle, or alternatively, allowing excess thermal energy from the passenger compartment to be transferred to those components, e.g. to store the thermal energy for later use.

[0029] Optionally, each compressor model comprises a 2D map of defining a relationship between a compressor energy costs and any two of: the thermal energy demand; the indicated amount of transferable thermal energy; and an ambient temperature value, and a corresponding compressor energy cost.

[0030] Advantageously, using values for two of: the thermal energy demand; the indicated amount of transferable thermal energy; and an ambient temperature value in conjunction with a 2D map of a relationship between those values has been found to provide for an accurate determination of compressor energy cost values in different operating modes of the climate control system, and can be readily implemented in real-time on common automotive controllers.

[0031] According to another aspect of the invention, there are provided computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform a method as described above.

[0032] Optionally, the computer readable instructions may be stored on a computer readable medium.

[0033] According to an embodiment, the control system for controlling a thermal management system comprises one or more controllers collectively comprising at least one electronic processor having an electrical input for receiving an input signal; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to perform any of the methods as described herein.

[0034] According to a further aspect of the invention, there is provided a control system for controlling a thermal management system of a vehicle, the control system comprising one or more processors collectively configured to obtain a plurality of compressor models, each compressor model associated with a respective one of the plurality of configurations of the climate control system, receive an indication of a configuration of the climate control system, receive an indication of an amount of transferable thermal energy associated with a powertrain of the electric vehicle, select a compressor model based on the indication of the configuration of the climate control system, determine a compressor energy cost associated with the compressor of the climate control system based on the indicated amount of transferable thermal energy and the selected compressor model, and provide an output signal based on the compressor energy cost.

[0035] Advantageously, the control system is operable to make an accurate determination of an energy cost associated with operating a compressor in a refrigerant circuit of a climate control system. In particular, different operating configurations of the climate control system, relating to different sources / sinks of thermal energy to be used, can be associated with different models of the compressor operation to allow an accurate determination to be made for each configuration.

[0036] Optionally, the indication of a configuration of the climate control system comprises an indication of a first configuration while the climate control system operates in a second configuration, wherein the first configuration is different from the second configuration.

[0037] In embodiments, the one or more processors are further configured to determine a predicted compressor energy cost for the first configuration of the thermal management system while the climate control system is operating in a second configuration.

[0038] In embodiments the one or more processors are configured to determine the compressor energy costs associated with the compressor by determining, for each configuration of the plurality of operating configurations of the climate control system, a compressor energy cost associated with the respective configuration, selecting an operating configuration for the climate control system based on the plurality of determined compressor energy costs, and providing the output signal, the output signal indicating the selected operating configuration.

[0039] According to an aspect of the present invention there is provided a vehicle comprising a control system as described above and a thermal management system communicatively coupled to the control system.

[0040] Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner.

[0041] BRIEF DESCRIPTION OF THE DRAWINGS

[0042] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0043] Figure 1 shows a system suitable for implementing embodiments of the invention;

[0044] Figure 2 illustrates a vehicle including the system of Figure 1 and suitable for implementing embodiments of the invention;

[0045] Figure 3 illustrates a schematic representation of a climate control system suitable for implementing embodiments of the invention;

[0046] Figure 4 illustrates a method of selecting an operating mode of a vehicle thermal management system according to embodiments of the invention; and

[0047] Figure 5 illustrates a control system suitable for performing the method of Figure 4, according to embodiments of the invention.

[0048] DETAILED DESCRIPTION

[0049] Components of an electric vehicle, such as a battery electric vehicle (BEV) , or plug-in hybrid electric vehicle (PHEV), may have target operating temperature ranges in which they are generally most efficient. Thermal management of the components of the electric vehicle to maintain the operating temperatures of the components in the target temperature ranges may therefore have a significant effect on the overall efficiency of the vehicle. Retaining thermal energy within the vehicle, for example by transferring heat energy from components having an excess of thermal energy to other components requiring heating, may reduce the amount of energy drawn from a fraction battery of the vehicle to supply heat energy.

[0050] Reconfigurable thermal management systems may facilitate transfer of thermal energy between different components of the electric vehicle. Estimating or predicting an energy cost associated with each configuration, or operating mode, of the thermal energy management system, may allow an operating mode having a low energy cost to be identified that is able satisfy thermal transfer requirements of components of the vehicle in an energy efficient way. However, with such reconfigurable thermal management systems, it may be difficult to accurately determine the amount of energy used by the thermal management system itself to transfer heat around the components of the vehicle to meet the various thermal transfer requirements of all of the components.

[0051] A thermal management system of an electric vehicle includes a climate control system, comprising heating, ventilation and air conditioning (HVAC), to manage the temperature of a cabin of the vehicle for occupant comfort. Such climate control systems are based on a refrigerant circuit that includes a compressor to increase the pressure of a working gas, or refrigerant, and drive the operation of the refrigeration circuit. In the case that the climate control system is operable in multiple different configurations, as part of a reconfigurable thermal management system, it may be difficult to accurately estimate energy use of the compressor when operating the climate control circuit to meet the thermal requirements of the vehicle.

[0052] According to embodiments of the invention, a control system may be operable to determine and output a compressor energy cost based on an amount of thermal energy transferable from a powertrain of the vehicle to the climate control system and a predictive model associated with a configuration of the climate control system.

[0053] With reference to Figure 1 , there is illustrated a vehicle thermal management system 100 for an electric vehicle in accordance with an embodiment of the present invention. The vehicle thermal management system 100 includes at least one controller 106 that is communicatively coupled to a powertrain thermal management system (PTM) 102 and a climate control system (CCS) 104 that comprises a heating, ventilation and air conditioning (HVAC) system, to receive state information and / or sensor readings from one or more components of the PTM 102 and HVAC, e.g. coolant or refrigerant temperature and mass flow rate measurements.

[0054] In embodiments, the controller 106 may be communicatively coupled to one or more components of the electric vehicle, for example via a Control Area Network (CAN) bus or similar network present on the vehicle 200, and operable to obtain thermal energy information from the components. The thermal energy information defines a thermal energy transfer requirement for each of the components of the electric vehicle. The controller 106 is further arranged to provide indications of a selected operating mode to the PTM 102 and CCS 104 to influence the operation of those subsystems.

[0055] The vehicle thermal management system 100 as illustrated in Figure 1 comprises one controller 106, although it will be appreciated that this is merely illustrative. The controller 106 comprises processing means 108 and memory means 110. The processing means 108 may be one or more electronic processing device 108 which operably executes computer-readable instructions. The memory means 110 may be one or more memory device 110. The memory means 110 is electrically coupled to the processing means 108. The memory means 110 is configured to store instructions, and the processing means 108 is configured to access the memory means 110 and execute the instructions stored thereon.

[0056] In Figure 2, controller 106, PTM 102, and CCS 104 are provided in electric vehicle 200, such as an automobile. A powertrain of the vehicle 200 comprises at least one electric drive unit 202a / b and a traction battery 204. The electric drive units 202a / b comprise one or more electric traction motors for propelling the vehicle 200. The fraction battery 204 is a high voltage (HV) battery and is configured to supply electrical current to the at least one drive unit 202a / b. In the present embodiment, the vehicle 200 comprises a front electric drive unit 202a for driving the front wheels of the vehicle 200; and a rear electric drive unit 202b for driving the rear wheels of the vehicle 200. In use, the front and rear electric drive units 202a, 202b are both powered by the traction battery 204. Each electric drive unit 202a / b may include power electronics, such as an inverter, to convert DC current sourced from the fraction battery 204 to AC current to be supplied to the electric traction motors. As illustrated in Figure 1 , the PTM 102 is coupled to the CCS 104 of the cabin of the vehicle which is able to control a temperature of the vehicle cabin for occupant comfort.

[0057] While the traction battery 204, electric drive units 202a / b and HVAC may be the most significant generators and / or users of thermal energy supplied by the PTM 102, it will be recognized that other vehicle components may be coupled to the PTM 102 and may have thermal requirements to be met by the PTM. For example, in embodiments, the vehicle 200 may further include separate power electronics, such as an on-board AC charger, that may be significant generators of thermal energy while requiring cooling to maintain an operating temperature. Similarly, in embodiments, the electrical vehicle 200 may be provided with computer processing hardware that requires active cooling.

[0058] The components of the vehicle may have associated target operating temperature ranges and operating a component outside of the respective target range may lead to increased power consumption of the component and the vehicle 200 as a whole. For example, when the temperature of the traction battery 204 increases, internal resistive losses within the traction battery 204 may also be expected to increase, while chemical reactions in the traction battery 204 may be inhibited when cold, similarly leading to increased losses in the battery. Such losses, when the powertrain components are not maintained within the desired operating temperature range, will result in reduced range for the vehicle 200.

[0059] The vehicle thermal management system 100 is operable as a supply or sink of thermal energy to components of the vehicle 200, and in particular PTM 102 is thermally coupled to the traction battery 204 and electric drive units 202a / b and able to extract or supply thermal energy to satisfy thermal energy transfer requirements of these components.

[0060] A heat exchanger, or chiller, is provided to allow thermal energy to be transferred from the PTM 102 to the CCS 104. Excess thermal energy generated in the electric drive units 202a / b, the traction battery 204, or other components coupled to the PTM 102 can be transferred through the heat exchanger to a refrigerant of the CCS 104 and used, for example, to provide heat to raise the temperature of the cabin to a desired level.

[0061] In an illustrative example of operation of the vehicle, thermal energy may be supplied via the PTM 102 to the traction battery 204 and electric drive units 202a / b when beginning operation of the vehicle 200 from cold to more quickly bring the components to the desired operating temperature range. During further operation of the vehicle 200, heat may be generated in the fraction battery 204 and electric drive units 202a / b, for example due to internal resistance of the cells of the traction battery 204. To maintain the temperature of the powertrain components within the desired temperature range, heat generated in the powertrain components of the vehicle 200 may be extracted by the thermal management system 102. The extracted thermal energy may be transferred between components of the vehicle 200, for example thermal energy extracted from the battery 204 may be supplied to CCS 104 for use in heating the cabin of the vehicle 200, or may be transferred off the vehicle 200, for example via a low temperature radiator to transfer the thermal energy to the outside environment.

[0062] The components of the vehicle may include one or more thermal customers. Each thermal customer may have a respective target operating temperature range, or a target operating temperature (for example where the upper and lower limits of the target operating temperature range may be considered to be the same). The vehicle thermal management system 100 may be arranged to control temperatures of the thermal customers, e.g., to cause the thermal customers to have respective temperatures that are in respective target operating temperature ranges. The traction battery 204; electric drive units 202; and vehicle cabin and / or CCS 104 are examples of thermal customers.

[0063] The vehicle thermal management system 100 may be operable in a large number of different modes of operation to meet the various thermal transfer requirements of the components. Identifying an operating mode having a lowest, or at least a reduced, energy cost for operation of the vehicle thermal management system 100, to meet the current thermal energy transfer requirements of the vehicle components, may be difficult and may depend on a range of factors. Some of those factors may be external to the vehicle, such as an ambient temperature.

[0064] Furthermore, selecting an operating mode based only on a current state of the vehicle component may not allow changes in the generation of heat in the vehicle to be taken into account. For example, for an electric vehicle 200 being driven on a clear highway, the power supplied by the battery may be relatively high, leading to significant heat generation within the traction battery 204 due to internal resistance. At the same time, significant airflow may be expected over a low temperature radiator of the vehicle. An operating mode for the vehicle thermal management system 100 may be selected to extract heat generated within the traction battery 204 and reject that heat through the low temperature radiator to the environment, while providing a portion of the heat energy to the CCS 104 for cabin heating. The electric vehicle 200 may then slow, for example due to congestion on the highway or leaving the highway for a local road, resulting in reduced heat generation in the traction battery 102 which may now be insufficient for cabin heating. In order to maintain a comfortable temperature for the cabin occupants, thermal energy may be supplied from another source, such as a heater drawing power from the traction battery 204, which undesirably uses power drawn from the traction battery.

[0065] A schematic representation of an example refrigerant circuit of a climate control system 104 is shown in Figure 3. The refrigerant circuit of Figure 3 includes an outside heat exchanger 302, chiller 304, in-vehicle evaporator 306, and in-vehicle condenser 308 arranged in a circuit. In-vehicle evaporator 306 may comprise more than one evaporator operable to provide multi-zone climate control within the vehicle. As would be appreciated by the skilled person, other components, such as one or more expansion valves, bypass conduits, etc. may be provided in the refrigerant circuit, but are not shown in Figure 3 for clarity and brevity. In operation, the compressor 310 operates to raise the pressure of the refrigerant which is then supplied to an input of condenser 308 where heat may be released for use in heating the cabin, if required. An output of condenser 308 is coupled to an input of the outside heat exchanger 302 which may be bi-directional and capable of recovering or rejecting heat energy from / to an ambient environment. An output of the outside heat exchanger 302 is coupled to an input of the chiller 304.

[0066] The chiller 304 is configured to selectively cool a thermal transfer fluid, or coolant, of the PTM 102 to allow heat energy to be transferred from the PTM 102 to the refrigerant of the CCS 104. An output of the chiller 302 is coupled to an input of the in-vehicle evaporator 306 where the refrigerant may absorb heat energy from the cabin (i.e. provide cooling). An output of the in-vehicle evaporator 306 is coupled to the compressor 310 to complete the refrigerant circuit. In some embodiments, the chiller 304 may be bi-directional and can be configured to transfer heat energy from the refrigerant of the CCS 104 to the coolant of the PTM 102, for example to allow heat energy recovered by cooling the cabin of the vehicle to be used in warming the fraction battery 204 to a target operating temperature.

[0067] One or more electric blowers, or fans, may be provided associated with in-vehicle evaporator 306 and / or in-vehicle condenser 308 to provide airflow over the evaporator / condenser and distribute thermal energy through the cabin. Similarly, airflow may be provided to outside heat exchanger 302 through the use of an electric fan, or by one or more controllable ducts, arranged to direct air from the outside environment over the outside heat exchanger 302.

[0068] Also provided in the refrigerant circuit are a number of bypass valves to allow components of the refrigerant circuit to be selectively bypassed according to a desired operating configuration of the climate control system 104. A first bypass valve 312 is arranged to selectively bypass refrigerant around the outside heat exchanger 302. A second bypass valve 314 is arranged to selectively bypass refrigerant around the chiller 304. A third bypass valve 316 is arranged to selectively bypass refrigerant around in-vehicle evaporator 306. Bypassing a component effectively removes that component from the refrigerant circuit so that no heat transfer occurs in that component. For example, by selectively bypassing chiller 304 using second bypass valve 314, heat exchange between the CCS 104 and PTM 102 is disabled.

[0069] Example operating modes, or configurations, of the CCS 104 may include:

[0070] • Cabin cooling with thermal energy rejected to ambient via the outside heat exchanger 302. In this configuration, second bypass valve 314 is selectively controlled to bypass chiller 304, while first and third bypass valves are selectively controlled to cause the refrigerant to pass through the outside heat exchanger 302 and in-vehicle evaporator 306;

[0071] • Cabin cooling and assisted powertrain cooling with thermal energy rejected to ambient via the outside heat exchanger 302. In this configuration, first, second and third bypass valves are selectively controlled to cause the refrigerant to pass through the outside heat exchanger 302, chiller 304, and in-vehicle evaporator 306. Thermal energy is transferred from PTM 102 via the chiller 304 providing increased cooling to the powertrain components coupled to the PTM 102;

[0072] • No cabin thermal demand with assisted powertrain cooling. In this configuration, first and second bypass valves are selectively controlled to cause the refrigerant to pass through the outside heat exchanger 302 and chiller 304. Third bypass valve 316 is selectively controlled to bypass in-vehicle evaporator 306 as there is no heat / cooling demanded by the cabin;

[0073] • Cabin heating supplied by ambient heat recovery. In this configuration, the second bypass valve 314 is selectively controlled to bypass chiller 304 and the third bypass valve 316 is selectively controlled to bypass in-vehicle evaporator 306, while first valve 312 is selectively controlled to cause the refrigerant to pass through the outside heat exchanger 302. Heat energy is recovered from ambient via the outside heat exchanger 302 and provided to the cabin via condenser 308;

[0074] • Cabin heating supplied by powertrain heat recovery. In this configuration, the first bypass valve 312 is selectively controlled to bypass the outside heat exchanger 302 and the third bypass valve 316 is selectively controlled to bypass in-vehicle evaporator 306, while second valve 314 is selectively controlled to cause the refrigerant to pass through the chiller 304. Heat energy is transferred from PTM 102 to the refrigerant via chiller 104 and provided to the cabin via condenser 308;

[0075] • Cabin heating supplied by ambient heat recovery and powertrain heat recovery. In this configuration, first and second bypass valves are selectively controlled to cause the refrigerant to pass through the outside heat exchanger 302 and chiller 304. Third bypass valve 316 is selectively controlled to bypass in-vehicle evaporator 306. Heat energy recovered from both ambient and the powertrain to provide a thermal energy requirement of the cabin. For the climate control system 104 illustrated in Figure 3, there may be more than one configuration that is able to meet a thermal energy demand associated with the cabin of the vehicle 200, or associated with the climate control system 104 controlling the temperature of the cabin,. For example, to supply heat to the cabin, different operating modes may be available to source thermal energy either from the powertrain via PTM 102 and chiller 304, and / or from ambient via outside heat exchanger 302. Furthermore, the relative efficiency of each available operating mode of the CCS 104 may depend on an operating mode of PTM 102 which may itself be reconfigurable to allow thermal energy transfer requirements of powertrain components to be met. Therefore, a whole system approach may be taken to identify a low energy cost operating mode or configuration for the vehicle thermal energy management system 100.

[0076] One approach to selecting an operating mode for the vehicle thermal management system 100 that is operable in a large number of operating modes, or configurations, is to determine energy costs associated with each of the different operating modes capable of meeting the thermal requirements of the vehicle components and select an operating mode to be implemented based on a lowest determined cost. This may allow for more reliable selection of an energy efficient operating mode. However, determining an energy cost for a particular configuration of the thermal management system may rely on one or more parameter values relating to operation of the thermal management system in that operating mode. An energy cost associated with operation of compressor 310 may be a significant contributor to the overall energy cost of an operating mode of the vehicle thermal management system 100.

[0077] According to embodiments, compressor energy costs are estimated using a predictive model associated with an indicated configuration of the climate control system 104. Figure 4 illustrates a method 400 of determining the compressor energy cost associated with a compressor of an electric vehicle 200, such as compressor 310. According to the illustrated method 400, a plurality of compressor models may be obtained 402, each compressor model associated with a configuration of the climate control system 104. An indication of a particular configuration of the climate control system 104 is received at block 404. The indicated configuration may be a current operating configuration of the climate control system 104 or may be for a different configuration from the current operating configuration.

[0078] An indication of an amount of transferable thermal energy associated with the powertrain of the electric vehicle, e.g. (electric drive units 202a / b, fraction battery 204, and / or a resistive heater of the PTM 102) is received at block 406. The amount of transferable thermal energy may be an amount of energy that may be transferred from PTM 102 to climate control system 104 via the chiller 304, either for use in cabin heating or to support cooling of the powertrain components. In some embodiments, the amount of transferable thermal energy may be an amount of thermal energy that may be transferred from the climate control system 104 to the PTM 102, for example to assist in raising a temperature of the traction battery 204 to a target operating range when initially operating the vehicle 100. In some embodiments, the amount of transferable energy may indicate that the powertrain, and PTM 102, is unable to provide a source or a sink of thermal energy at that time.

[0079] Based on the indicated configuration of the climate control system 104, a compressor model is selected at block 408, and a compressor energy cost is then determined 410 based on the selected compressor model and transferable thermal energy value. A signal representative of the compressor energy cost is then output at block 412, for example for use in predicting an energy cost associated with the indicated configuration of the climate control system 104.

[0080] In some embodiments, the compressor energy cost may be further based on the thermal energy demand associated with the climate control system 104. That is, the compressor energy cost may be determined based at least in part on an amount of energy to be transferred to / from the climate control system 104, for example to control the temperature of the vehicle cabin.

[0081] Should the thermal energy demand of the climate control system have a magnitude less than a first threshold value, the compressor energy cost may further be based on an ambient temperature value. That is, if the climate control system makes no demand for gain or loss of thermal energy, or at least less than the first threshold, then the compressor energy cost may be based significantly on the ambient environmental temperature.

[0082] Likewise, should a transferable energy value, based on the available transferable thermal energy associated with a powertrain of the electric vehicle, have a magnitude less than a second threshold value (which may be the same or different to the first threshold), the compressor energy cost may be further based on the ambient temperature value. That is, if the power train thermal management system has no requirement to gain or lose thermal energy, then the compressor energy cost may again be based significantly on the ambient environmental temperature. The available transferable thermal energy of the powertrain employed to determine the compressor energy cost for a given mode may be a maximum quantity transferable over a given period of time, i.e. an upper threshold amount of transferable energy.

[0083] In some embodiments, energy costs associated with a plurality of configurations may be determined based on compressor energy values, and therefore the method of Figure 4 may be repeated for each configuration of the plurality of configurations to predict compressor energy costs for each configuration. In this way, compressor energy costs for a number of different operating modes of the climate control system 104 can be predicted without changing the operating mode of the climate control system 104. An operating mode for the climate control system 104 may then be selected based on the determined compressor energy costs, for example by selecting an operating mode associated with a lowest compressor energy cost or lowest total energy cost, including the compressor energy cost.

[0084] In some embodiments, the determined compressor energy cost may be combined with other energy cost values associated with an operating mode of the climate control system 104, such as energy costs associated with operating electric fans, a drag cost associated with providing airflow to outside heat exchanger 302, etc. to determine an energy cost value associated with the operating mode of the climate control system 104. The energy cost value associated with the operating mode of the climate control system 104 may be further combined with a predicted energy cost for an operating mode of PTM 102 to provide a total energy cost associated with operating the vehicle thermal management system 100 in a particular operating mode, or configuration. The total energy cost may be used to select a low, or lowest, energy cost operating mode capable of meeting the thermal demands placed on the system for the vehicle thermal management system 100.

[0085] In embodiments, the compressor energy cost associated with each operating mode can be calculated for a certain period of time, for example the next five minutes, providing a prediction of the energy cost for each operating mode. In such embodiments, the transferable thermal energy value may be representative of a maximum amount of thermal energy that may be exchanged between the powertrain and the climate control system over the predetermined period of time, and the cabin demand may be representative of an amount of thermal energy to be supplied to (or extracted from) the cabin over the predetermined period of time.

[0086] The compressor models may be determined by identifying correlations between sensor measurements and / or parameter values in a data set capturing sensor measurements and operating parameter values for a wide range of operating conditions and for each of the configurations of the climate control system 104. For example, each compressor model may define a relationship between the energy cost of operating the compressor in the associated configuration with one or more of an ambient temperature of the outside environment, a cabin thermal energy demand, and an amount of transferable energy associated with the powertrain via the chiller 304.

[0087] The data set may be generated empirically on a instrumented test system of the vehicle thermal management system, or using a numerical model to simulate the thermal management system, (i.e. a computer aided engineering (CAE) model of the vehicle thermal management system 100 or climate control system 104). According to embodiments, multiple simulations of the climate control system 104 can be performed for each operating mode of the CCS 104, and covering the full range of expected environmental and operating conditions. For example, simulations may be performed for each operating mode of the CCS 104 for a wide range of ambient temperature and humidity values covering the range of conditions that may be experienced in the real world.

[0088] To generate each compressor model, a regression analysis may be performed on the portion of the data set corresponding to the operating mode associated with that compressor model, for example a multi-factor linear regression analysis can be performed, to identify a relationship between a simulated compressor energy cost and the one or more of the ambient temperature of the outside environment, cabin thermal energy demand, and amount of transferable energy associated with the powertrain via the chiller 304.

[0089] In embodiments, sensitivity analysis may be applied to the data set for each compressor model to determine which one, or two, of the one or more of the ambient temperature of the outside environment, cabin thermal energy demand, and amount of transferable energy associated with the powertrain via the chiller 304 have the greatest impact on the predicted compressor energy cost. Having identified the most parameters having the greatest correlation with the compressor energy cost, the model to determine the compressor energy cost may then be generated based on the relationship between the identified most impactful parameter values and the predicted compressor energy cost, according to the regression analysis. In embodiments, the model may be provided as coefficients of an equation defining the determined relationship, as a look- up-table (LUT) of compressor energy costs and associated parameter values, as a map, such as a 2D map, of a relationship between parameter values and a corresponding compressor energy cost, etc.

[0090] Certain methods and systems as described herein may be implemented by one or more processors that processes program code that is retrieved from a non-fransitory storage medium. Figure 5 shows an example of a device 500 comprising a computer-readable storage medium 520 coupled to at least one processor 510. The computer-readable media 520 can be any media that can contain, store, or maintain programs and data for use by or in connection with an instruction execution system. Computer-readable media can comprise any one of many physical media such as, for example, electronic, magnetic, optical, electromagnetic, or semiconductor media. More specific examples of suitable machine-readable media include, but are not limited to, a hard drive, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory, or a portable disc. In Figure 5, the computer-readable storage medium comprises program code to perform a method corresponding to the embodiment shown in Figure 4, that is: obtaining 402 a plurality of compressor models; receiving 404 an indication of a configuration of the climate control system 104; receiving 406 an indication of an amount of transferable thermal energy associated with the powertrain of the vehicle 200; selecting 408 a compressor model based on the indication of the configuration of the climate control system 104; determining 410 a compressor energy cost based on the transferable thermal energy value and the selected compressor model; and providing 412 an output representative of the compressor energy cost.

[0091] The device 500 may be included in controller 106 of an electric vehicle 200, as illustrated in FIG. 2, for example.

[0092] It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1 . A method of determining a compressor energy cost associated with a compressor of a climate control system of an electric vehicle, the climate control system operable in a plurality of configurations, the method comprising: obtaining a plurality of compressor models, each compressor model associated with a respective one of the plurality of configurations of the climate control system; receiving an indication of a configuration of the climate control system; receiving an indication of an amount of transferable thermal energy associated with a powertrain of the electric vehicle; selecting a compressor model based on the indication of the configuration of the climate control system; determining a compressor energy cost associated with the compressor of the climate control system based on the indicated amount of transferable thermal energy and the selected compressor model; and providing an output signal based on the compressor energy cost.

2. The method of claim 1 , wherein receiving an indication of a configuration of climate control system comprises receiving an indication of a first configuration while the climate control system is operating in a second configuration, wherein the first configuration is different from the second configuration.

3. The method of claim 2, wherein the determined compressor energy cost comprises a predicted compressor energy cost for the first configuration of the climate control system while the climate control system is operating in a second configuration.

4. The method of any preceding claim, the method further comprising: wherein determining the compressor energy cost associated with the compressor comprises determining, for each configuration of the plurality of operating configurations of the climate control system, the compressor energy cost associated with the compressor when operating in the respective operating configuration; selecting an operating configuration for the climate control system based on the plurality of determined compressor energy costs; and wherein the output signal indicates the selected operating configuration.

5. The method of any preceding claim, wherein the compressor energy cost is further determined based on a thermal energy demand associated with the climate control system.

6. The method of claim 5, further comprising, in response to the thermal energy demand having a magnitude less than a first threshold value, determining the compressor energy cost further based on an ambient temperature value.

7. The method of any of claims 1 to 5 further comprising, in response to the indicated amount of transferable thermal energy having a magnitude less than a second threshold value, determining the compressor energy cost further based on an ambient temperature value.

8. The method of any preceding claim, wherein the indicated amount of transferable thermal energy comprises an upper threshold amount of thermal energy that may be exchanged between the powertrain and the climate control system over a predetermined period of time.

9. The method of any preceding claim, wherein each compressor model comprises a map of defining a relationship between a compressor energy cost and any two of: the thermal energy demand; the indicated amount of transferable thermal energy; and an ambient temperature value.

10. Computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method according to any of claims 1 to 9.

11. A control system for controlling a thermal management system of a vehicle, the control system comprising one or more processors collectively configured to: obtain a plurality of compressor models, each compressor model associated with a respective one of a plurality of configurations of a climate control system; receive an indication of a configuration of the climate control system; receive an indication of an amount of transferable thermal energy associated with a powertrain of the electric vehicle; select a compressor model based on the indication of the configuration of the climate control system; determine a compressor energy cost associated with a compressor of the climate control system based on the indicated amount of transferable thermal energy and the selected compressor model; and provide an output signal based on the compressor energy cost.

12. The control system of claim 11 , wherein the indication of a configuration of the climate control system comprises an indication of a first configuration while the climate control system operates in a second configuration, wherein the first configuration is different from the second configuration.

13. The control system of claim 12, wherein the one or more processors are further configured to determine a predicted compressor energy cost for the first configuration of the climate control system while the climate control system is operating in a second configuration.

14. The control system of any of claims 11 to 13, wherein the one or more processors are configured to determine the compressor energy costs associated with the compressor by: determining, for each configuration of the plurality of operating configurations of the climate control system, a compressor energy cost associated with the respective configuration; selecting an operating configuration for the climate control system based on the plurality of determined compressor energy costs; and providing the output signal, the output signal indicating the selected operating configuration.

15. A vehicle comprising: the control system of any of claims 11 to 14; and a thermal management system comprising a climate control system communicatively coupled to the control system.

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