Control of vehicle thermal managment systems

Abstract

A method for controlling a thermal management system of an electric vehicle, the thermal management system having a plurality of operating modes. In each operating mode the thermal management system is configured to transfer thermal energy among a respective set of components of the electric vehicle via one or more thermal transfer fluids. For at least one component, a target thermal energy transfer between the component and the one or more thermal transfer fluids is obtained. An aggregated thermal energy transfer availability for the respective set of components is obtained, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective set of components is collectively able to exchange with the one or more thermal transfer fluids in the operating mode. Based on the aggregated thermal energy transfer availability it is determined whether the target thermal energy transfers of the at least one component in the respective set of components are achievable in the operating mode.

Description

[0001] CONTROL OF VEHICLE THERMAL MANAGEMENT SYSTEMS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method and control system for controlling a thermal management system of an electric vehicle. Aspects of the invention relate to a method, to a control system, to computer readable instructions, a computer readable medium, and to a vehicle.

[0004] BACKGROUND

[0005] The temperature of certain components of electric vehicles may have a significant effect on the efficiency of operation of those components. For example, when the temperature is cold, chemical reactions in traction batteries may be inhibited, and in extreme cold the battery electrolyte may freeze, significantly increasing losses in the battery. Conversely, as the temperature of a traction battery increases, resistive losses in the battery may increase. Thus, it may be beneficial to maintain the traction battery of an electric vehicle within a certain range of temperatures. Similarly motors, electronics, and other components of the vehicle, along with the vehicle cabin for human comfort, may have desired temperature ranges in which they should ideally be maintained.

[0006] However, managing the temperature of components in the system may draw a significant amount of power from the fraction battery, for example when powering a resistive heater, which itself may reduce the efficiency of the use of electrical power provided from the traction battery and therefore reduce the range of the electric vehicle.

[0007] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0008] SUMMARY OF THE INVENTION

[0009] Aspects and embodiments of the invention provide a method for controlling a thermal management system, and an associated control system, computer readable instructions, computer readable medium, and vehicle, as claimed in the appended claims.

[0010] Disclosed arrangements provide a method for controlling a thermal management system of an electric vehicle, the thermal management system configured to transfer thermal energy between components of a first set of components in a first operating mode of the thermal management system, the method comprising: determining whether energy transfers requested by components of the first set of components are achievable in the first operating mode; and in dependence on the determining, providing an output indicating whether the energy transfers requested by the components are achievable in the first operating mode.

[0011] Accordingly, compatibility of an operating mode with thermal demands may be efficiently determined in order to provide selection of an appropriate operating mode.

[0012] An aspect of the invention provides a method for controlling a thermal management system of an electric vehicle, wherein the thermal management system has a plurality of operating modes, and wherein in each operating mode the thermal management system is configured to transfer thermal energy among a respective set of components of the electric vehicle via one or more thermal transfer fluids, the method comprising, for one or more of the operating modes: obtaining, for at least one component in the respective set of components, a respective target thermal energy transfer between the component and the one or more thermal transfer fluids; obtaining an aggregated thermal energy transfer availability for the respective set of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective set of components is collectively able to exchange with the one or more thermal transfer fluids in the operating mode; and determining, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of the at least one component in the respective set of components are achievable in the operating mode.

[0013] Accordingly, compatibility of an operating mode with thermal demands may be efficiently determined in order to provide selection of an appropriate operating mode.

[0014] The method may comprise providing an output indicating the result of the determining.

[0015] The output may be used, for example, in selecting an operating mode. In some examples, the result of the determining may be used to eliminate an operating mode from consideration.

[0016] The method may comprise selecting an operating mode based on the determination. The method may comprise selecting an operating mode based on the output. The method may comprise, when it is determined that target thermal energy transfers in the set of components are not achievable in the operating mode, outputting an error margin (or error value) indicating a difference between the target thermal energy transfers and the aggregated thermal energy transfer availability.

[0017] In some examples, when it is determined that the target thermal energy transfers in the set of components are not achievable in the operating mode, a circuit error margin (or circuit error value) may be output. The circuit error margin indicates a difference between the target thermal energy transfer and the thermal energy transfer that is achievable (i.e. , the thermal energy transfer that comes closest to meeting the target thermal energy transfers) in the thermal circuit. In other words, the error margin indicates how close the operating mode can come to achieving the target thermal energy transfers, and may correspond with a portion of the target thermal energy transfers that is not balanced by the achievable thermal energy transfers.

[0018] In some examples respective circuit error margins (circuit error values) may be determined for each thermal circuit of an operating mode and an overall error margin (or overall error value) may be determined for the operating mode by combining the circuit error margins for each of the thermal circuits of the operating mode. This may include, for example, adding absolute values of the circuit error margins to obtain the overall error margin of the operating mode.

[0019] In some examples, an operating mode may be considered for selection even when it is determined that the operating mode does not achieve the target thermal energy transfers. For example when all candidate operating modes are determined not to achieve target thermal energy transfers, an operating mode may be selected based on how close the candidate modes are to achieving target thermal energy transfers.

[0020] The method may comprise selecting an operating mode based on the error margin.

[0021] The selected operating mode may be an operating mode to be implemented in the electric vehicle. An output may be provided as a signal to the thermal management system to provide an indication of a recommended operating mode of the system. In some examples, the output causes the thermal management system to transition to the selected operating mode.

[0022] In some examples, the aggregated thermal energy transfer availability indicates a controllable, or variable, rate at which thermal energy is transferable from the set of components to the thermal transfer fluids beyond, or in addition to, the target thermal energy transfers. For example, the aggregated thermal energy transfer availability may be indicative of transfer capacities of components that are in excess of any target transfer associated with the respective components.

[0023] In some examples each of the target thermal energy transfers may correspond with an amount of thermal energy to be transferred. For example, a requested amount of thermal energy, or an amount of excess thermal energy associated with a component. The aggregated thermal energy transfer availability may correspond with an amount of thermal energy that is transferrable, e.g. an amount of thermal energy that can be provided to components of the set of components or an amount of thermal energy that can be removed from components of the set of components.

[0024] In some examples, each of the target thermal energy transfers corresponds with a target rate of transfer of thermal energy between the respective component and the one or more thermal transfer fluids.

[0025] In some examples, the aggregated thermal energy transfer availability corresponds with a rate at which thermal energy is transferrable, by the components of the set of components, to or from the one or more thermal transfer fluids.

[0026] In some examples, the aggregated thermal energy transfer availability is indicative of a range of rates at which thermal energy is transferrable between components in the set of components and the thermal transfer fluids, the target thermal energy transfers are indicative of a target rate of transfer of thermal energy between the at least one component and the one or more thermal transfer fluids, and determining whether target thermal energy transfers in the set of components are achievable in the operating mode comprises determining whether the range of rates is compatible with the target rate of transfer of thermal energy.

[0027] In some examples, the method includes aggregating the target thermal energy transfers of the one or more components to obtain an aggregated target thermal energy transfer rate for the set of components, and wherein the range of rates is determined to be compatible with the target rate of transfer of thermal energy if the aggregated target thermal energy transfer rate is balanced by a rate within the range of rates. For example, a rate in the range of rates may balance the aggregated target thermal energy transfer rate if there is a rate in the range of rates that sums to zero with the aggregated target thermal energy transfer rate.

[0028] The respective set of components may include one or more components that are not associated with a respective target thermal energy transfer. The one or more components that are not associated with a respective target thermal energy transfer may be capable of transferring thermal energy to or from the one or more thermal transfer fluids. The one or more components that are not associated with a respective target thermal energy transfer may include one or more of a coolant heater, a radiator, an outside heat exchanger, or a chiller.

[0029] The electric vehicle may include a set of components having respective target temperature ranges, with the components in the set of components being thermal customers. The thermal management system may be arranged to control temperatures of the thermal customers, e.g. to cause the thermal customers have respective temperatures that are in respective target temperature ranges. As such a thermal customer may also be referred to as a controlled component or control target, as the thermal customers may be viewed as components of the electric vehicle that are ultimately controlled by the thermal management system. In some examples, the thermal customers are not components of the thermal management system, but are in thermal communication with the thermal management system.

[0030] Each thermal customer may have a respective target thermal energy transfer. Each of the at least one component having a respective target thermal energy may be a thermal customer. The thermal management system may be arranged to control temperatures of thermal customers, e.g. to cause the thermal customers to have respective temperatures that are in respective target operating temperature ranges.

[0031] Accordingly, the method may determine whether thermal energy requirements of the thermal customers is achievable in the operating modes. The thermal management system may provide an energy efficient approach to controlling the temperature of thermal customers.

[0032] The thermal customers may include one or more of: a traction battery, an electric drive unit, or a cabin.

[0033] Accordingly, the thermal management system may control the temperature of a traction battery, an electric drive unit, or a cabin.

[0034] In some examples, obtaining an aggregated thermal energy transfer availability comprises obtaining upper and lower aggregated thermal energy transfer availability values indicative of a range of achievable thermal transfers, the upper aggregated thermal energy transfer availability value greater than the lower aggregated thermal energy transfer availability value.

[0035] In some examples, the method comprises: obtaining an aggregated target thermal energy transfer value for the at least one component, based on the one or more target thermal energy transfers; obtaining an upper energy balance value indicative of a sum of the upper aggregated thermal energy transfer availability value and the aggregated target thermal energy transfer value; and obtaining a lower energy balance value indicative of a sum of the lower aggregated thermal energy transfer availability value and the aggregated target thermal energy transfer value, wherein the target thermal energy transfers of the at least one component are determined to be achievable if the upper energy balance value is greater than or equal to zero and the lower energy balance value is less than or equal to zero.

[0036] In some examples, each component of the set of components has an associated thermal energy transfer availability value indicative of a thermal transfer, between the respective component and the thermal transfer fluids, beyond (or in addition to) any target thermal energy transfer associated with the component. The upper aggregated thermal energy transfer availability value is based on positive thermal energy transfer availability values, and the lower aggregated thermal energy transfer availability is based on negative thermal energy transfer availability values. For example, the upper aggregated thermal energy transfer availability value may be a sum of positive thermal energy transfer availability values, and the lower aggregated thermal energy transfer availability may be a sum of negative thermal energy transfer availability values.

[0037] A thermal energy transfer capability value of a component may be indicative of a thermal transfer achievable by the respective component. For example, the thermal energy transfer capability value of a component may be indicative of a thermal energy transfer that has the greatest magnitude achievable by the component. The thermal energy transfer capability value may be positive when the thermal energy transfer capability value is indicative of a transfer of thermal energy from the component to the thermal transfer fluids, and may be negative when the thermal energy transfer capability value is indicative of a transfer of thermal energy to the component from the thermal transfer fluids.

[0038] For a component that is not a thermal customer, the thermal energy transfer availability value may be the thermal energy transfer capability value of the component. For a thermal customer, the thermal energy transfer availability value may be indicative of a thermal energy transfer that the component is able to provide beyond the target thermal energy transfer value.

[0039] In some examples, a component having a thermal energy deficit has a target thermal energy transfer with opposite sign to a target thermal energy transfer of a component having a thermal energy excess.

[0040] In some examples, the target thermal energy transfer value of each of the one or more components indicates an energy transfer to change the temperature of the component to be closer to a target operating temperature range of the component. For example, the target thermal energy transfer value may be a first sign (e.g . positive) if the component is above an upper value (or upper limit) of its target operating temperature range. The target thermal energy transfer value may be a second sign (e.g. negative) if the component is below a lower value (or lower limit) of its target operating temperature range. The target thermal energy transfer value may be zero if the component is in its target operating temperature range (i.e. has a temperature between the upper and lower values / limits of its target operating temperature range).

[0041] For example, a component having a thermal energy excess may have a positive target thermal energy transfer, and a component having a thermal energy deficit may have a negative target thermal energy transfer.

[0042] Accordingly, thermal energy excesses and deficits may be represented in a consistent manner.

[0043] In some examples, the aggregated thermal energy transfer availability of a set of components may be based on aggregating respective thermal energy transfer availability values of the components in the set. In some examples, upper and lower aggregated thermal energy transfer availability values may be determined, wherein only positive thermal energy transfer availability values contribute to the upper aggregated thermal energy transfer availability value, and only negative thermal energy transfer availability values contribute to the lower aggregated thermal energy transfer availability value.

[0044] In some examples, each operating mode of the thermal management system defines one or more thermal circuits, each thermal circuit comprising a subset of components that are in thermal communication with each other via a respective subset of thermal transfer fluids, and wherein the method comprises, for each thermal circuit in each of the one or more operating modes: obtaining, for at least one component in the respective subset of components, a respective target thermal energy transfer between the component and the respective subset of thermal transfer fluids in the thermal circuit in the operating mode; obtaining an aggregated thermal energy transfer availability for the respective subset of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective subset of components is collectively able to exchange with the respective subset of thermal transfer fluids in the thermal circuit in the operating mode; and determining, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the thermal circuit in the operating mode.

[0045] Accordingly, multiple thermal circuits of an operating mode may be considered.

[0046] Components in different thermal circuits may be considered to be not in thermal communication, e.g. such that there is no thermal energy transfer between the thermal circuits, or the thermal energy transfer between the thermal circuits is negligible. In other words, where a first set of components is in a first thermal circuit of an operating mode and a second set of components is in a second thermal circuit of the operating mode, the first and second sets may be non-overlapping, such that there are no components that are in both the first set and in the second set.

[0047] In some examples, the method comprises: determining whether all target thermal energy transfers of the thermal management system are achievable in each respective operating mode, based on the determination, for each of the one or more thermal circuits defined by the operating mode, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the operating mode; and providing one or more outputs indicating the result of the determining whether all target thermal energy transfers of the thermal management system are achievable in each respective operating mode.

[0048] Accordingly, the determination of whether the target thermal energy transfers of the thermal management system are achievable in the operating mode may take into account all of the thermal circuits of the operating mode.

[0049] In examples, all target thermal energy transfers of the thermal management system are determined to be achievable in an operating mode if it is determined that each of the target thermal energy transfers in each of the respective thermal circuits are achievable in the operating mode.

[0050] Accordingly, the determination of whether the target thermal energy transfers of the thermal management system are achievable in the first operating mode may take into account all of the thermal circuits of the first operating mode.

[0051] In some examples, the method comprises: determining respective energy costs associated with the operating modes.

[0052] In some examples, the method comprises: determining respective energy costs associated with the operating modes for operating modes in which the respective target thermal energy transfers are determined to be achievable.

[0053] Herein a subset of a set may be a proper subset, i.e. a subset that does not include all of the elements of the set, or an improper subset, i.e. a subset that includes all of the elements of the set.

[0054] In some examples, a first subset of components associated with a first operating mode may have one or more components in common with a second subset of components associated with a second operating mode. In some examples, the first and second subsets of components have no components in common. In some examples, all components in the first subset of components may be included in the second subset of components. In some examples, at least one of: the first subset of components includes at least one component that is not in the second subset of components, and the second subset of components includes at least one component that is not in the first subset of components.

[0055] The examples can conform to various operating modes having different groupings of the components into different thermal circuits.

[0056] In some examples, the first operating mode has a first set of thermal circuits, and the second operating mode has a second set of thermal circuits, wherein components of each thermal circuit are in thermal communication with other components of the same thermal circuit. Put another way, for each thermal circuit, thermal energy is transferred between the components of the thermal circuit (via one or more thermal transfer fluids). Thermal energy transfer between different thermal circuits in the same set of thermal circuits may be negligible.

[0057] The method may include outputting a result of the determining operating modes in which the respective target thermal energy transfers are achievable.

[0058] In some examples, wherein when it is determined that target thermal energy transfers of the at least one component in the respective set of components are not achievable in the operating mode the method further comprises: outputting a circuit error margin, the circuit error margin indicating a difference between the target thermal energy transfer and a thermal energy transfer that is achievable; and determining for each thermal circuit of the operating mode an overall error margin by combining the circuit error margins for each of the thermal circuits of the operating mode.

[0059] In some examples, the method comprises: determining, for operating modes in which the respective target thermal energy transfers are determined to be achievable, respective energy costs associated with the operating modes, and selecting an operating mode based on the energy costs.

[0060] Accordingly, it is possible to select an operating mode of the thermal management system taking into consideration an energy cost associated with the operating mode as well as energy transfer requirements of components of the vehicle. This facilitates energy efficiency, e.g. by allowing an operating mode with a low (or lowest) energy cost to be selected from among operating modes that satisfy the requirements of the components.

[0061] In some examples, the energy cost of an operating mode comprises a thermal energy cost value representing an amount of thermal energy transferred off the vehicle in that operating mode and an actuator energy cost value representing an energy cost associated with operating the thermal management system in that operating mode.

[0062] Accordingly, an energy cost for each potential operating mode of the thermal management system of the electric vehicle may be evaluated and a mode may be selected based on this (e.g. having a lowest energy cost, such that the most efficient operating mode to meet the required thermal transfer requirements of the components of the vehicle may be selected). In particular (but not exclusively), the energy cost may include both the cost of operating the thermal management system, for example energy required to operate a compressor, and also a thermal energy cost value representing an amount of thermal energy lost from the vehicle, e.g. via a radiator to the environment. Thus, the method is able to select an operating mode for the thermal management system that retains as much thermal energy as possible while meeting the required cooling and / or heating requirements of the components, leading to increased efficiency overall.

[0063] In some examples, the actuator energy cost value associated with an operating mode is representative of at least one of: an energy cost of operating a compressor according to that operating mode; a valve actuation energy cost associated with that operating mode; a vehicle drag cost associated with operation of a heat exchanger according to that operating mode; an energy cost of operating a pump according to that operating mode; and an energy cost of operating a fan according to that operating mode.

[0064] Accordingly, the method is able to take into account a range of energy costs associated with the operation of the thermal management system, including energy costs associated with transitioning the thermal management system from a first operating mode to a second operating mode, e.g. valve actuation costs.

[0065] In some examples, the method further comprises selecting an operating mode based on the determinations as described. The selection of an operating mode may be based on one or more determinations as described. Furthermore, the selection of an operating mode may instead or additionally be based upon outputs of differences or outputs of determinations as described.

[0066] Accordingly, an operating mode may be selected based fully or partially on the determination of whether the target thermal energy transfers of the at least one component in the respective set of components are achievable in the operating mode. Such determination may be based on the aggregated thermal energy transfer availability,

[0067] An operating mode may be selected based fully or partially on determining whether the range of rates at which thermal energy is transferrable between components in the set of components and the one or more thermal transfer fluids is compatible with the target rate of transfer of thermal energy between the at least one component and the one or more thermal transfer fluids. An operating mode may be selected based fully or partially on determining that the range of rates is compatible with the target rate of transfer of thermal energy if the aggregated target thermal energy transfer rate is balanced by a rate within the range of rates. Such aggregated thermal energy transfer availability may then comprise obtaining upper and lower aggregated thermal energy transfer availability values indicative of a range of achievable thermal transfers, the upper aggregated thermal energy transfer availability value being greater than the lower aggregated thermal energy transfer availability value.

[0068] An operating mode may be selected based fully or partially on determining that the target thermal energy transfers of the at least one component are achievable if the upper energy balance value is greater than or equal to zero and the lower energy balance value is less than or equal to zero.

[0069] An operating mode may be selected based fully or partially on determining whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the thermal circuit in the operating mode. Such determination may be based on the aggregated thermal energy transfer availability.

[0070] An operating mode may be selected based fully or partially on determining whether all target thermal energy transfers of the thermal management system are achievable in each respective operating mode, based on the determination, for each of the one or more thermal circuits defined by the operating mode, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the operating mode.

[0071] An operating mode may be selected based fully or partially on determining, for operating modes in which the respective target thermal energy transfers are determined to be achievable, respective energy costs associated with the operating modes.

[0072] Accordingly, an operating mode may be selected which achieves target thermal energy transfers whilst also minimizing the energy costs associated with the operating mode.

[0073] An operating mode may be selected based fully or partially on the output of a circuit error margin, the circuit error margin indicating a difference between the target thermal energy transfer and a thermal energy transfer that is achievable.

[0074] An operating mode may be selected based fully or partially on determining for each thermal circuit of the operating mode an overall error margin by combining the circuit error margins for each of the thermal circuits of the operating mode.

[0075] Accordingly, when it is determined that target thermal energy transfers of the at least one component in the respective set of components are not achievable in the operating mode an operating mode may be selected which minimizes circuit error margins. An operating mode may then be selected based additionally on minimizing the energy costs associated with the operating mode as well as minimizing circuit error margins.

[0076] Aspects provide a control system for controlling a thermal management system of an electric vehicle, the control system comprising one or more processors collectively configured to perform any of the methods described herein.

[0077] Aspects provide a control system for controlling a thermal management system of an electric vehicle, the control system comprising one or more processors collectively configured to: determine whether energy transfers requested by components of the first set of components is achievable in the first operating mode; and in dependence on the determining, provide an output indicating whether the energy transfers requested by the components are achievable in the first operating mode.

[0078] Aspects provide a control system for controlling a thermal management system of an electric vehicle, wherein the thermal management system has a plurality of operating modes, and wherein in each operating mode the thermal management system is configured to transfer thermal energy among a respective set of components of the electric vehicle via one or more thermal transfer fluids, the control system comprising one or more processors collectively configured to, for one or more of the operating modes: obtain, for at least one component in the respective set of components, a respective target thermal energy transfer between the component and the one or more thermal transfer fluids; obtain an aggregated thermal energy transfer availability for the respective set of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective set of components is collectively able to exchange with the one or more thermal transfer fluids in the operating mode; and determine, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of the at least one component in the respective set of components are achievable in the operating mode.

[0079] Aspects provide computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform any of the methods described herein. Aspects provide a computer readable medium comprising computer readable instructions that, when executed by a processor, cause performance of any of the methods described herein.

[0080] The computer readable medium may be a non-transitory computer readable medium.

[0081] Aspects provide a vehicle comprising a control system, as described herein, and a thermal management system communicatively coupled to the control system.

[0082] 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.

[0083] BRIEF DESCRIPTION OF THE DRAWINGS

[0084] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which, in accordance with embodiments of the invention:

[0085] FIG. 1 illustrates a thermal management system for an electric;

[0086] FIG. 2 illustrates a vehicle including the system of FIG.;

[0087] FIG. 3 illustrates a schematic representation of a powertrain thermal management system;

[0088] FIG. 4A to FIG. 4F illustrate example configurations of the thermal management;

[0089] FIG. 5 illustrates a method 500 for controlling a thermal management system of an electric vehicle;

[0090] FIG. 6 illustrates an example of an algorithm 600;

[0091] FIG. 7 shows a method 700 for obtaining a thermal energy transfer availability value for a thermal customer;

[0092] FIG. 8 illustrates a method 800; and

[0093] FIG. 9 illustrates a control system suitable for performing methods described herein.

[0094] DETAILED DESCRIPTION

[0095] A control system may evaluate operating modes of a thermal management system of an electric vehicle, such as a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV). The control system may determine whether target transfers of thermal energy between components of the electric vehicle are achievable in each operating mode. This can facilitate selection of an appropriate operating mode of the electric vehicle's thermal management system, given its current condition and taking into account thermal targets for the components of the electric vehicle.

[0096] With reference to FIG. 1 , there is illustrated a thermal management system 100 for an electric vehicle 200 in accordance with an embodiment of the present invention. The thermal management system 100 includes a controller 106 that is communicatively coupled to a powertrain thermal management system (PTM) 102 and a climate control system 104. The climate control system 104 may comprise heating, ventilation and air conditioning (HVAC) system. The controller 106 is to receive state information and / or sensor readings from one or more components of the powertrain thermal management system 102 and the climate control system 104, e.g., temperature and mass flow rate values (e.g., based on measurements or models). The mass flow rate may indicate, for example, one or more of a mass flow of a coolant of a cooling circuit, a refrigerant of a refrigerant circuit, or air flow in an air conditioning unit.

[0097] In embodiments, the controller 106 may be communicatively coupled to one or more components of the electric vehicle 200, for example via a controller area network (CAN) bus or similar network present on the electric vehicle 200, and operable to obtain operating state information from the components, the operating state information defining a thermal energy transfer requirement for each of the components of the electric vehicle 200. The controller 106 is further arranged to provide indications of a selected operating mode to the powertrain thermal management system 102 and a climate control system 104 to influence the operation of those systems.

[0098] In the arrangement of FIG. 1 , the thermal management system 100 comprises one controller 106, although it will be appreciated that this is merely illustrative. The controller comprises processing means (e.g., processor 108) and memory means (e.g., memory device 110). The processing means may be one or more electronic processing device which operably executes computer-readable instructions 112. The memory means may be one or more memory device 110. The memory means is electrically coupled to the processing means. The memory means is configured to store instructions 112, and the processing means is configured to access the memory means and execute the instructions 112 stored thereon. FIG. 2 illustrates an electric vehicle 200, such as an automobile, provided with a controller 106, powertrain thermal management system 102, and the climate control system 104, as shown in FIG. 1 . A powertrain of the electric vehicle 200 comprises at least one electric drive unit 202 (e.g., front electric drive unit 202a and rear electric drive unit 202b) and a traction battery 204. The electric drive units 202 comprise one or more electric traction motors for propelling the electric vehicle 200. The fraction battery 204 is a high voltage (HV) battery and is configured to supply electrical current to the at least one electric drive unit 202. In the present embodiment, the electric vehicle 200 comprises a front electric drive unit 202a for driving the front wheels of the electric vehicle 200; and a rear electric drive unit 202b for driving the rear wheels of the electric vehicle 200. In use, the front electric drive unit 202a and rear electric drive unit 202b are both powered by the traction battery 204. Each electric drive unit 202 may include power electronics, such as an inverter, to convert DC current sourced from the traction battery 204 to AC current to be supplied to the electric traction motors. As illustrated in FIG. 1 , the powertrain thermal management system 102 is coupled to the climate control system 104 of the cabin of the electric vehicle 200 which is able to control a temperature of the vehicle cabin for occupant comfort.

[0099] While the fraction battery 204, electric drive units 202 and climate control system 104 may be the most significant generators and / or users of thermal energy supplied by the powertrain thermal management system 102, it will be recognized that other vehicle components may be coupled to the powertrain thermal management system 102 and may have thermal requirements to be met by the powertrain thermal management system 102. For example, in embodiments, the electric 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, the electric vehicle 200 may be provided with computer processing hardware that requires active cooling.

[0100] The components of the electric vehicle 200 may have target operating temperature ranges, and operating a component outside of an associated target operating temperature range may lead to increased power consumption by the component or by the electric vehicle 200. For example, when the temperature of the traction battery 204 increases, internal resistive losses within the fraction 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 204. Such losses may result in reduced range for the electric vehicle 200 when the powertrain components are not maintained within the desired operating temperature range.

[0101] The thermal management system 100 is operable as a source (supply) or sink of thermal energy to components of the vehicle 200. The powertrain thermal management system 102 is thermally coupled to the traction battery 204 and electric drive units 202 and is able to extract or supply thermal energy to satisfy thermal energy transfer requirements of these components. Similarly, thermal energy may be transferred between the cabin and the climate control system 104. For example, energy may be supplied to the fraction battery 204 and electric drive units 202 when beginning operation of the electric vehicle 200 from cold to more quickly bring the components to the desired operating temperature range. During operation of the electric vehicle 200, heat may be generated in the fraction battery 204 and electric drive units 202, 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 electric vehicle 200 may be extracted by the thermal management system 100. The extracted thermal energy may be transferred between components of the electric vehicle 200 or may be transferred off the electric vehicle 200, for example via a low temperature radiator, to transfer the thermal energy to the outside environment.

[0102] The 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 a most efficient operating mode for the thermal management system 100, based on the current thermal requirements of the vehicle’s 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.

[0103] A schematic representation of an example powertrain thermal management system 102 is shown in FIG. 3. A control valve apparatus 302 is configured to control the circulation of thermal transfer fluid, or coolant, to manage a thermal load of the front electric drive unit 202a, the rear electric drive unit 202b, the battery 204 and the climate control system 104 of the vehicle cabin for occupant comfort. The powertrain thermal management system 102 comprises a coolant heater 304; a first heat exchanger 306; and a second heat exchanger 308. The coolant heater 304 is configured to heat the coolant, for example to provide fast warm-up of traction battery 204 when initially operating the electric vehicle 200. The coolant heater 304 may be a high voltage (HV) heater that draws electrical power directly from fraction battery 204. In some examples the cooling system comprises, or is in thermal communication with, at least one of a fraction battery; an electric drive unit; a radiator (second heat exchanger 308); and a coolant heater.

[0104] The first heat exchanger 306 can be configured selectively to cool the coolant of the powertrain thermal management system 102. A refrigerant circuit of the climate control system 104 is coupled to a refrigerant side of the first heat exchanger 306 to cause the first heat exchanger 306 to operate as a chiller. Thus, the first heat exchanger 306 enables the transfer of heat energy extracted from the coolant to the refrigerant of the climate control system 104. In this way, excess thermal energy may be transferred from powertrain components for use in heating the cabin of the vehicle. In some embodiments, the first heat exchanger 306 may be bi-directional and allow the transfer of thermal energy from the refrigerant of the climate control system 104 to the coolant of the powertrain thermal management system 102, for example to allow for the supply heat from the outside environment via an outside heat exchanger of the climate control system 104 to heat the coolant. The refrigerant circuit may be coupled to an outside heat exchanger operable to transfer heat between the refrigerant and the outside environment. The supply of refrigerant can be halted to reduced or prevent heat exchange in the first heat exchanger 306. The second heat exchanger 308 is a low temperature heat exchanger (or a low temperature radiator) and is operative to reject heat from the coolant to the outside environment.

[0105] The control valve apparatus 302 comprises a first pump 310 and a second pump 312. The powertrain thermal management system 102 comprises a first coolant circulation loop 314; and a second coolant circulation loop 316. A liquid coolant, or thermal transfer fluid, is circulated through the first coolant circulation loop 314 and second coolant circulation loop 316 to perform supply or sink of thermal energy to the front electric drive unit 202a and rear electric drive unit 202b and the battery 204. At least one coolant temperature sensor 318 may be provided for measuring the temperature of the coolant. In the illustrated example, the coolant temperature sensor 318 is provided at an inlet to the second pump 312. The coolant temperature sensor 318 measures the temperature of the coolant supplied to the second pump 312. An electric fan (not shown) may optionally be provided to circulate air over the second heat exchanger 308 to promote cooling of the coolant.

[0106] The first coolant circulation loop 314 is configured to supply coolant to the fraction battery 204. The coolant heater 304 and the first heat exchanger 306 are provided in the first coolant circulation loop 314. The coolant heater 304 is provided downstream of the fraction battery 204 and, in use, is operative to heat the coolant. The first heat exchanger 306 is disposed upstream of the traction battery 204 and, in use, can be configured to cool the coolant prior to introduction into the traction battery 204. As described herein, the first coolant circulation loop 314 and second coolant circulation loop 316 may be selectively connected to each other to enable the supply of coolant from the first heat exchanger 306 to the front electric drive unit 202a and rear electric drive unit 202b.

[0107] Bypass conduits may be provided for one or more components of the first 314 or second 316 coolant loops. A bypass conduit may control lably opened or closed by a valve to control the supply of coolant to the respective component. For example, the first coolant circulation loop 314 comprises a battery supply conduit 320, and a battery bypass conduit 322. The battery supply conduit 320 is configured to supply coolant to the battery 204. The battery bypass conduit 322 can be selectively opened and closed to control the supply of coolant to perform cooling of the battery 204.

[0108] The second coolant circulation loop 316 is configured to supply coolant to the front electric drive unit 202a and rear electric drive unit 202b. The second heat exchanger 308 is provided in the second coolant circulation loop 316 downstream of the front electric drive unit 202a and rear electric drive unit 202b. In some examples, the front 202a and rear 202b electric drive units may each be provided with a respective bypass conduit (not shown) to selectively bypass the respective electric drive unit 202a, 202b, accordingly, transfer of thermal energy to or from the front 202a and rear 202b electric drive units may be permitted when the respective electric drive unit 202 is not bypassed and may be avoided when the respective electric drive unit 202 is bypassed.

[0109] In use, the second heat exchanger 308 rejects thermal energy from the coolant to the external environment. The second coolant circulation loop 316 comprises a heat exchanger coolant conduit 324 for supplying coolant to the second heat exchanger 308; and a heat exchanger bypass conduit 326 for selectively bypassing the second heat exchanger 308. The control valve apparatus 302 may provide proportional control of the coolant flow rate through the heat exchanger bypass conduit 326, thereby confrollably increasing or decreasing the flow through the second heat exchanger 308.

[0110] Control valve apparatus 302 includes crossflow valves 328 that are arranged to couple or decouple the first coolant circulation loop 314 (battery coolant circulation loop) and second coolant circulation loop 316 (electric drive unit coolant circulation loop). In addition, the crossflow valves 328 determine whether the first heat exchanger 306 is coupled in a coolant circulation loop with the battery 204 or the electric drive units 202. In other words, the crossflow valves 328 determine whether the first heat exchanger 306 is coupled in the first coolant circulation loop 314 or the second coolant circulation loop 316, or both when the first 314 and second 316 coolant circulation loops are coupled. The coupling and decoupling of the first coolant circulation loop 314, second coolant circulation loop 316 and first heat exchanger 306, as well as a state (on or off) of the first heat exchanger 306 defines the configuration of the thermal management system 100.

[0111] The first heat exchanger 306, when activated, couples the coolant circulation loop that it is in with the refrigerant circuit. As such, the first heat exchanger 306 is an example of a thermal link component of the powertrain thermal management system 102. A thermal link component is a component that is switchable between a first state, in which the thermal link component provides thermal communication between the cooling system and the refrigerant system, and a second state, in which the thermal link component does not provide thermal communication between the cooling system and the refrigerant system. For example, the thermal link component may be placed in the first state by including the thermal link component in both the coolant circulation loop and the refrigerant circuit (e.g., by not bypassing the thermal link component in the cooling system and not bypassing the thermal link component in the refrigerant system) . Similarly, the thermal link component may be placed in the second state by bypassing the thermal link component in one or both of the cooling system and the refrigerant system.

[0112] Herein coupling between the first coolant circulation loop 314, second coolant circulation loop 316 and / or the refrigerant circuit indicates that the first coolant circulation loop 314, second coolant circulation loop 316 and / or refrigerant circuit are in thermal communication, such that thermal energy may be transferred between them. Similarly, when they are decoupled, they are not in thermal communication, and no thermal energy (or a negligible amount of thermal energy) is transferred between them.

[0113] The control valve apparatus 302 allows the thermal management system 100 to be controlled to selectively bypass certain components of the powertrain thermal management system 102, such as the second heat exchanger 308, as well as to selectively couple the first coolant circulation loop 314 and second coolant circulation loop 316 together to allow transfer of thermal energy between the components served by the different coolant circulation loops. This means that there may exist a large number of possible arrangements of the thermal management system 100. For each arrangement, one or more components may be controlled to different states, for example the first heat exchanger 306 may be on or off depending on whether refrigerant is provided to the first heat exchanger 306, the second heat exchanger 308 may be selectively bypassed, etc. As such, there may be multiple operating modes of the thermal management system 100 for each of the configurations of the thermal management system 100, resulting in a large total number of possible operating modes for the thermal management system 100 from which an operating mode is to be selected by controller 106.

[0114] In embodiments, climate control system 104 includes the refrigerant circuit, the refrigerant circuit including a compressor, at least one internal evaporator operable to extract thermal energy from air in the cabin, at least one internal condenser operable to supply thermal energy to the air in the cabin and an outside heat exchanger for exchanging thermal energy with an outside environment. As discussed above, refrigerant of the climate control system 104 may be selectively provided to first heat exchanger 306 to allow heat energy to be transferred between the coolant of the powertrain thermal management system 102 and the refrigerant of the climate control system 104. Thus, climate control system 104 may be operable in multiple modes. In some embodiments, selection of an operating mode for the climate control system 104 may be coordinated with a selected operating mode for powertrain thermal management system 102 to further improve overall efficiency of the vehicle thermal management system 100. In some examples, the refrigerant system may have a plurality of refrigerant configurations, and each refrigerant configuration defines a direction of flow of thermal transfer fluid to at least one component of the refrigerant system.

[0115] In examples, the thermal management system 100 may include a cooling system and a refrigerant system.

[0116] The cooling system may be operable in a plurality of coolant configurations, each coolant configuration defining a direction of flow of thermal transfer fluid to at least one component of the cooling system, and each operating mode may be associated with a respective coolant configuration.

[0117] In some examples, the refrigerant system may be operable in a plurality of refrigerant configurations, each refrigerant configuration defining a direction of flow of thermal transfer fluid to at least one component of the refrigerant system, where each operating mode is associated with a respective refrigerant configuration.

[0118] In some examples, each operating mode may be associated with a respective coolant configuration and a respective refrigerant configuration. In some examples, each operating mode may further be associated with a respective state of a thermal link component of the thermal management system 100, such that the operating mode depends on whether or not a coolant circulation loop is in thermal communication with a refrigerant circuit via the thermal link component.

[0119] 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 thermal management system 100 may be arranged to control temperatures of the thermal customers, e.g., to cause the thermal customers have respective temperatures that are in respective target operating temperature ranges. The fraction battery 204; electric drive units 202; and vehicle cabin (or cabin air conditioning unit) are examples of thermal customers.

[0120] When a thermal customer is above its target operating temperature range the thermal customer is to act as a source of thermal energy, whereas when the thermal customer is below its target operating temperature range, the thermal customer is to act as a sink of thermal energy, and when the thermal customer is within its target operating temperature range, where that is of sufficient breadth, the thermal customer is either available to act as a source or a sink of thermal energy, or to act as neither a source nor a sink of thermal energy. FIG. 4A to FIG. 4F show examples of configurations of a thermal management system that includes the powertrain thermal management system of FIG. 3. Here, the first coolant circulation loop 314 includes the battery 204 and the coolant heater 304, the second coolant circulation loop 316 includes the electric drive units 202 and the second heat exchanger 308. For illustration purposes, a refrigerant circuit 408 is shown as having an internal evaporator 404 and an outside heat exchanger 406, but the refrigerant circuit 408 may include other additional or alternative components.

[0121] The first coolant circulation loop 314 and second coolant circulation loop 316 may be selectively coupled or decoupled by the crossflow valves 328. Further the first heat exchanger 306 may be coupled with either of the first coolant circulation loop 314 or the second coolant circulation loop 316 (or both when the first coolant circulation loop 314 and the second coolant circulation loop 316 are coupled with each other) by the crossflow valves 328. As shown in FIG. 3, the valves 328 in the first and second coolant circulation loops 314, 316 may be arranged in multiple operational positions interconnecting their respective ports 1 -4 and 5-8. In FIGS. 4A-4F they have the following arrangements, as will become evident from the description below of the circulation loops resulting when the valves are so arranged:

[0122] FIGS. 4A and 4B: as shown in FIG. 3, with ports 1 and 3, 2 and 4, 5 and 7 and 6 and 8 being interconnected;

[0123] FIGS. 4C and 4D: different from FIG 3 and 4A, having ports 5 and 8 interconnected and ports 6 and 7 interconnected; and FIG. 4E and 4F: as for FIGS. 4C and 4D, except ports 1 and 4 are interconnected, as are ports 2 and 3.

[0124] In FIG. 4A the first coolant circulation loop 314 and second coolant circulation loop 316 are decoupled, and the first heat exchanger 306 is in the first coolant circulation loop 314. The first heat exchanger 306 is not active, such that the first coolant circulation loop 314 is decoupled from the refrigerant circuit 408. This leads to three thermal circuits being formed. The first thermal circuit 402a corresponds with the first coolant circulation loop 314 and includes the battery 204 and coolant heater 304. The second thermal circuit 402b corresponds with the second coolant circulation loop 316 and includes the electric drive units 202 and the second heat exchanger 308. The third thermal circuit 402c corresponds with the refrigerant circuit 408 and includes the internal evaporator 404 and the outside heat exchanger 406.

[0125] FIG. 4B shows the same configuration as FIG. 4A, with the first coolant circulation loop 314 and second coolant circulation loop 316 being decoupled and the first heat exchanger 306 being in the first coolant circulation loop 314. However, in FIG. 4B the first heat exchanger 306 is active, and so the first coolant circulation loop 314 is coupled with the refrigerant circuit 408. This leads to two thermal circuits. A first thermal circuit 402a includes battery 204, coolant heater 304, first heat exchanger 306, internal evaporator 404 and outside heat exchanger 406. The second thermal circuit 402b includes the electric drive units 202 and the second heat exchanger 308.

[0126] In FIG. 4C the first coolant circulation loop 314 and second coolant circulation loop 316 are coupled. The first heat exchanger 306 is also coupled in the first coolant circulation loop 314 and the second coolant circulation loop 316. The first heat exchanger 306 is not active, such that the first coolant circulation loop 314 and second coolant circulation loop 316 are decoupled from the refrigerant circuit 408. This leads to two thermal circuits being formed. The first thermal circuit 402a corresponds with the combined first coolant circulation loop 314 and second coolant circulation loop 316, and includes the battery 204, coolant heater 304, electric drive units 202, and second heat exchanger 308. The second thermal circuit 402b corresponds with refrigerant circuit 408.

[0127] FIG. 4D shows the same configuration as FIG. 4C, with the first coolant circulation loop 314 and second coolant circulation loop 316 being coupled. However, in FIG. 4D the first heat exchanger 306 is active, and so the first coolant circulation loop 314 and second coolant circulation loop 316 are coupled with the refrigerant circuit 408. This leads to an arrangement with one thermal circuit 402a that includes all of the illustrated components.

[0128] In FIG. 4E the first coolant circulation loop 314 and second coolant circulation loop 316 are decoupled, as in FIG. 4A, but now the first heat exchanger 306 is in the second coolant circulation loop 316. The first heat exchanger 306 is not active, such that the second coolant circulation loop 316 is decoupled from the refrigerant circuit 408. This leads to three thermal circuits being formed. These thermal circuits are the same as in FIG. 4A, except that the first heat exchanger 306 is in the second coolant circulation loop 316. As such, the thermal transfer in this arrangement is the same or similar to the arrangement of FIG. 4A. However, these modes of operation are not necessarily equivalent. For example, an energy cost to transition to the mode of FIG. 4A may be less than the energy cost to transition to the mode of FIG. 4E, and so the mode of FIG. 4A may be a better selection than the mode of FIG. 4E in that case. The energy cost of transitioning may be associated with driving actuators to control the crossflow valves 328, for example.

[0129] FIG. 4F shows the same configuration as FIG. 4E, with the first coolant circulation loop 314 and second coolant circulation loop 316 being decoupled and the first heat exchanger 306 being in the second coolant circulation loop 316. However, in FIG. 4F the first heat exchanger 306 is active, and so the second coolant circulation loop 316 is coupled with the refrigerant circuit 408. This leads to two thermal circuits. A first thermal circuit 402a includes battery 204 and coolant heater 304. The second thermal circuit 402b includes the electric drive units 202, the second heat exchanger 308, the first heat exchanger 306, the internal evaporator 404, and outside heat exchanger 406.

[0130] Each operating mode may be associated with a corresponding set of thermal circuits. For example the operating mode illustrated in FIG. 4A is associated with a set of three thermal circuits, while the operating mode illustrated in FIG. 4B is associated with a set of two thermal circuits. Components of each thermal circuit are in thermal communication with other components of the same thermal circuit (via the thermal transfer fluids) . For each thermal circuit, thermal energy is transferred, or transferrable, between the components of the thermal circuit (via one or more thermal transfer fluids). Thermal energy transfer between different thermal circuits in the same set of thermal circuits may be negligible.

[0131] Components in different thermal circuits may be considered to be not in thermal communication, e.g., such that there is no thermal energy transfer between the thermal circuits, or the thermal energy transfer between the thermal circuits is negligible. In other words, where a first set of components is in a first thermal circuit of an operating mode and a second set of components is in a second thermal circuit of the operating mode, the first and second sets may be non-overlapping, such that there are no components that are in both the first set and in the second set.

[0132] Some thermal customers may be indicated as usable either to receive or supply thermal energy (e.g., act as a source or a sink) when the thermal customer is within its target operating temperature range. For example, when the thermal customer is within its target operating temperature range and has capacity to either provide thermal energy to other components, or to store excess thermal energy. Such thermal customers may be designated as thermal storage components.

[0133] A component designated as a thermal storage component has an associated operating temperature range, and is to be used to store excess thermal energy when the thermal storage component is within its target operating temperature range. This may reduce the transfer of thermal energy off of the electric vehicle 200, instead retaining the thermal energy on the electric vehicle 200 for possible future use. Accordingly, if a component has a subsequent deficit in thermal energy, the previously stored excess thermal energy may be extracted from the thermal storage component and be provided to the component having the deficit. This may, for example, avoid or reduce usage of the coolant heater 304 to address the thermal energy deficit, leading to a corresponding reduction in electrical energy drawn from the traction battery 204 to power the coolant heater 304. When a component designated as a thermal storage component is within its target operating temperature range, the component is to act as a source or a sink of thermal energy.

[0134] In some examples, one or both of a fraction battery or an electric drive unit may be designated as a thermal storage component.

[0135] Some thermal customers may be indicated as not to receive or supply thermal energy when the thermal customer is in its target operating temperature range. That is, in some examples one or more thermal customers are not designated as thermal storage components (or are designated as not thermal storage components). When a component designated as not a thermal storage component is within its target operating temperature range, the component is to act as neither a source nor a sink of thermal energy (i.e. , is to act as neither a heat source nor a heat sink when it is in its target operating temperature range).

[0136] Accordingly, where the thermal customer is designated as not to be used as a thermal storage component, an indication that the thermal customer is below its target operating temperature range may correspond with a state in which thermal energy is to be supplied to the thermal customer (i.e., it is to act as a heat sink); an indication that the thermal customer is above its target operating temperature range may correspond with a state in which thermal energy is to be extracted from the thermal customer (i.e., it is to act as a heat source); and an indication that the thermal customer is within its target operating temperature range may correspond with a state in which no thermal energy is to be transferred from or to the thermal customer (i.e., it is to act as neither a heat source nor a heat sink).

[0137] In some examples a cabin of the electric vehicle 200 may be designated as not usable as a thermal storage component. This may avoid unwanted temperature changes in the cabin, for example.

[0138] Arrangements, such as those shown in FIG. 3 and FIG. 4A to FIG. 4F, lead to a significant number of possible operating modes for the thermal management system 100. In each of the configurations, components such as the second heat exchanger 308, coolant heater 304 and outside heat exchanger 406 may each be active or inactive. Similarly, one or more components may be bypassed in the thermal transfer fluid loop, such that bypassed components do not exchange thermal energy via that thermal management system 100. In some examples the number of modes may exceed one hundred. In some examples, the number of modes may exceed two hundred.

[0139] Where a system is capable of fewer configurations, a smaller number of potential operating modes exist and there are fewer options for heat transfer among the components of a vehicle. In such systems, the selection of an operating mode may be straightforward, e.g., using a lookup table that indicates a mode based on temperatures of components of the vehicle (e.g., taking into account the temperatures of three or fewer components). However, the reduced options for transferring heat between components may limit the achievable energy efficiency.

[0140] In some systems that provide a range of configurations of the thermal management system 100 that are comparable to the examples in FIG. 3 and FIG. 4A to FIG. 4F, the full benefit of these configurations may not be achieved where the system significantly limits selectable combinations of configurations with operation states of components (such as a heater on / off or radiator used / bypassed). In such systems, only a small subset of the potential modes is selectable. Similarly to the case where few configurations are available, in such systems, a mode of the thermal system may be selected based on relative temperatures of the components according to a table of selectable modes. In such systems, the number of selectable modes may be fewer than 20 or fewer than 15, for example. Accordingly, these systems provide limited flexibility in controlling heat transfer between components, potentially losing opportunities for energy efficiency.

[0141] As noted above, in systems having a relatively small number of selectable operating modes (e.g., 20 or fewer), an operating mode may be selected in a relatively straightforward way, e.g. from a table based on temperatures of the components. The table (or other mode selection method) may be defined in advance based on engineer intuition.

[0142] Where the number of selectable operating modes significantly increases, a selection of a mode based on engineer intuition becomes impractical, and reliably selecting an appropriate operating mode becomes increasingly difficult using a simple table-based, rules-based or similar, approach.

[0143] Where a large number of operating modes are to be considered, detailed consideration of each operating mode (e.g., by obtaining energy costs for every operating mode) may be computationally prohibitive. This may be ameliorated by removing non-compliant operating modes from consideration without obtaining associated energy costs. Computational efficiency may be important where computational resources are limited, such as in some on-board controllers in vehicles. In addition, in some implementations, interfaces with other elements of the vehicle control system may place strict time constraints on the selection of the operating mode, and for this reason also, computational efficiency may be important when implementing the selection of the operating mode.

[0144] According to some examples, compatible operating modes are determined. Compatible operating modes are operating modes in which thermal energy is removed from components that have excess thermal energy, and thermal energy is provided to components that have a thermal energy deficit. Accordingly, compatible operating modes may be considered to be operating modes that have thermal energy transfer directions that are consistent with the requirements of the thermal customers (i.e. , cool, or remove thermal energy from thermal customers that are indicated as too hot; and heat, or provide thermal energy to, thermal customers that are too cool). In addition, where a thermal customer is indicated as being to neither receive nor supply thermal energy (e.g., where the thermal customer is not designated as a thermal storage component and is in its target operating temperature range), the compatible operating modes may be modes that do not transfer thermal energy to or from the thermal customer when it is in range (in addition to having appropriate thermal energy transfers with thermal customers that request thermal energy transfers).

[0145] A recommended operating mode (e.g., an operating mode to be implemented in the thermal management system 100) may be selected based on the determination of compatible operating modes. For example, the compatible operating modes may form a shortlist of operating modes from which a recommended operating mode may be selected.

[0146] This may be more computationally efficient than directly selecting a single operating mode from among the full set of operating modes. This approach may be particularly beneficial, albeit not necessarily essential, where there are a large number of operating modes, e.g., by reducing the number of operating modes that are to be assessed in detail when selecting a recommended operating mode.

[0147] In some examples, energy costs associated with different operating modes are determined and used in the selection of an operating mode to be implemented. This may allow for more reliable selection of an energy efficient operating mode. Moreover, the selection of the operating mode may better take into account the current state of the components of the vehicle compared with temperature-based or table-based approaches.

[0148] FIG. 5 illustrates a method 500 for controlling a thermal management system 100 of an electric vehicle 200. As described above, the thermal management system 100 has a plurality of operating modes, and in each operating mode the thermal management system 100 is configured to transfer thermal energy among a respective set of components of the electric vehicle via one or more thermal transfer fluids. Each of the components of the set of components are capable of transferring thermal energy to or from the one or more thermal transfer fluids. According to the method 500, the operations 502, 504 and 506 are carried out for one or more of the operating modes. For example, the operations 502, 504 and 506 may be carried out for each operating mode of thermal management system 100. In some examples, the operations 502, 504 and 506 may be carried out for a subset of operating modes. One or more target thermal energy transfers are obtained at operation 502. Each target thermal energy transfer is associated with a respective component of the electric vehicle 200. The one or more components may be, for example, thermal customers that are in the same thermal circuit in the operating mode under consideration. The target thermal energy transfer describes a target, or desired, thermal energy transfer between the component and one or more thermal transfer fluids. As described above, the thermal transfer fluids may include one or more of a coolant of a coolant circuit, and a refrigerant of a refrigerant circuit 408, for example. Obtaining the target thermal energy transfers may include receiving data indicating the target thermal energy transfers, or may include calculating the target thermal energy transfers based on received data, e.g., data indicating measurements obtained by sensors of the thermal management system 100.

[0149] An aggregated thermal energy transfer availability is obtained at operation 504. The aggregated thermal energy transfer availability is associated with a set of components of the electric vehicle 200, and includes the one or more components for which target thermal energy transfers were obtained at operation 502. The set of components may be components that are in thermal communication via the thermal management system 100 in the operating mode under consideration. The aggregated thermal energy transfer availability is indicative of the thermal energy that the set of components is collectively able to exchange with the thermal transfer fluids in the operating mode. Obtaining the aggregated thermal energy transfer availability may include receiving data indicating the aggregated thermal energy transfer availability, or may include calculating the aggregated thermal energy transfer availability based on received data, e.g., data indicating measurements obtained by sensors of the thermal management system 100.

[0150] At operation 506 it is determined whether the target thermal energy transfers of the at least one component are achievable in the operating mode. The determination is based on the aggregated thermal energy transfer availability.

[0151] Accordingly, the method 500 assesses whether a desired thermal energy transfer is achievable in the operating mode. An operating mode to implement in the thermal management system 100 may be selected based on the determination. In some examples, the determination may be used to generate a shortlist of operating modes for further consideration.

[0152] An output indicative of the determination may be provided, for example, to a module that is to carry out a selection of an operating mode to implement in the thermal management system 100. In some examples, the output may be provided as a signal to a module of the controller 106. In some examples, the output is provided to a module of the controller 106 in order to select a recommended operating mode that is to be implemented in the thermal management system 100. In some examples, the module of the controller 106 may be a hardware module, a software module, a routine, etc.

[0153] In some examples, when it is determined that the target thermal energy transfers in the set of components are not achievable in the operating mode, a circuit error margin (or circuit error value) may be output. The circuit error margin indicates a difference between the target thermal energy transfer and the thermal energy transfer that is achievable in the thermal circuit. That is, a difference between the target thermal energy transfer and the achievable thermal energy transfer that comes closest to meeting the target thermal energy transfers in the thermal circuit. In other words, the error margin may indicate how close the operating mode can come to achieving the target thermal energy transfers. The error margin may correspond with a portion of the target thermal energy transfers that are not balanced (or not balanceable) by the achievable thermal energy transfers.

[0154] Accordingly, this allows selection of an operating mode based, at least in part, on how well the target thermal energy transfers are achieved in each mode. An operating mode may be selected based on the error margin. For example, where it is determined that the target thermal energy transfers are not achievable in any of the operating modes, an operating mode having a lowest error margin (i.e., coming closest to achieving the target thermal energy transfers) may be selected.

[0155] The set of components may correspond with the components in a thermal circuit of the mode under consideration, and the one or more components having target thermal energy transfers may be thermal customers of the thermal circuit. Taking the example of thermal circuit 402a of FIG. 4A, the set of components includes the battery 204 and coolant heater 304. The one or more components in this case is battery 204. Similarly, in the thermal circuit 402b of FIG. 4A, the set of components would be the front electric drive unit 202a, the rear electric drive unit 202b and the second heat exchanger 308, with the front electric drive unit 202a and rear electric drive unit 202b being the one or more components having target thermal energy transfers.

[0156] The set of components may include components that do not have target thermal energy transfers. The one or more components that do not have target thermal energy transfers may include one or more of a coolant heater 304, a radiator (e.g., second heat exchanger 308), an outside heat exchanger 406 heat exchanger, or a chiller. For example, in the thermal circuit 402b of FIG. 4A, the second heat exchanger 308 is an example of a component of the set of components that does not have a target thermal energy transfer, and so is not one of the one or more components.

[0157] The one or more target thermal energy transfers obtained at operation 502 may be indicative of rates of target thermal energy transfer between the respective component and the thermal transfer fluid. That is, the target thermal energy transfer may be a measure of energy per unit time, or power (e.g., measured in Watts). In other examples, the target thermal energy transfers could be indicated in terms of a desired (or target) rate of change of temperature (e.g., measured in degrees per minute). The heat capacity of the component relates the temperature change in the component with the heat (thermal energy) transferred to or from the component, as would be understood by the skilled person.

[0158] The target thermal energy transfers may be based on information from sensors, such as coolant temperature sensor 318, that provide information on a status of components of the electric vehicle 200. The sensors may indicate temperatures of respective components of the electric vehicle 200. The status of some components that are not directly monitored by a sensor may be derived using available sensor measurements and a model of the thermal management system 100, or based on a look up table, for example.

[0159] In some examples, received information may indicate current temperatures of thermal customers, and the target thermal energy transfers be derived from the indicated temperatures and other information about the system, such as a lookup table storing target operating temperature ranges associated with the thermal customers, and / or information indicating whether a component is usable to store excess thermal energy. In this way, the target thermal energy transfers may be indicated by the received information without being explicitly included in the received information. In other examples, the target thermal energy transfers may be explicitly included in received operating state information.

[0160] The target thermal energy transfers may be obtained from a lookup table, derived from a predetermined formula, or based on a simulation, etc. In some examples, each thermal customer may be associated with a value indicative of the rate of thermal energy transfer that is determined to cause the temperature of the component to approach its target operating temperature range at a satisfactory rate or in a satisfactory time (e.g. , as determined during design of the system). For example, a component may be associated with a fixed value as its target thermal energy transfer. In other examples, the target thermal energy transfer value may be set based on a difference between the current temperature of the component and a target temperature range of the component. For example, the target thermal energy transfer value may be set in order to bring the component within its target operating temperature range within a predetermined period of time.

[0161] In some examples the target thermal energy transfer rate may be based on a model of the thermal customer. In some examples, the target thermal energy transfer rate may be obtained from a lookup table.

[0162] The target thermal energy transfer may be indicative of a thermal energy transfer that will change the temperature of the component (e.g., a thermal customer) to be closer to its target operating temperature range.

[0163] A thermal customer that is above its target operating temperature range may be considered to have an excess of thermal energy, and similarly, a thermal customer that is below its target operating temperature range may be considered to have a deficit of thermal energy. A component having a thermal energy deficit may be indicated as having a target thermal energy transfer with opposite sign to a target thermal energy transfer of a component having a thermal energy excess. The examples herein indicate the target thermal energy transfer as positive for a component having excess thermal energy, and negative for a component having a deficit of thermal energy. According to this convention, components that are too hot, and so are to provide thermal energy to the thermal transfer fluids have a positive target thermal energy transfer and components that are too cool, and so are to receive thermal energy from the thermal transfer fluids have a negative target thermal energy transfer. A component having a temperature within its target operating temperature range may have a target thermal energy transfer of zero.

[0164] In some examples, an aggregated target thermal energy transfer value may be determined for the set of components by aggregating the target thermal energy transfers of the one or more components. In some examples, the aggregated target thermal energy transfer value is the sum of the target thermal energy transfers. Where the target thermal energy transfers are indicative of thermal energy transfer rates, the aggregated target thermal energy transfer value may be an aggregated target thermal energy transfer rate.

[0165] Returning to the example of FIG. 4A, the aggregated target thermal energy transfer value of the first thermal circuit 402a merely corresponds with the target thermal energy transfer of the battery 204, as this is the only thermal customer in the first thermal circuit 402a. In comparison, the aggregated target thermal energy transfer value of the second thermal circuit 402b is the sum of the target thermal energy transfers of the front electric drive unit 202a and rear electric drive unit 202b.

[0166] The aggregated thermal energy transfer availability that is received at operation 504 may be indicative of a rate at which thermal energy is transferable, by the set of components, to or from the one or more thermal transfer fluids. The aggregated thermal energy transfer availability may be based on statuses of one or more of the components, such as temperatures of the components. The statuses may be obtained using sensors, such as coolant temperature sensor 318. In some examples, one or more statuses may be derived using a model of the thermal management system 100 or using a lookup table. Some components may be operable with different operating states, such as different flow rates of thermal transfer fluid, or different power levels (such as electrical power supplied to coolant heater 304, or electrical power supplied to a fan of second heat exchanger 308). This may permit each component to controllably vary the rate at which thermal energy is transferred between the component and the thermal transfer fluids. As such, the aggregated thermal energy transfer availability may be indicative of a range of transfer values at which thermal energy is transferable between the components of the set of components and the thermal transfer fluids. For example, the aggregated thermal energy transfer availability may indicate an upper aggregated thermal energy transfer availability value and lower aggregated thermal energy transfer availability value (e.g ., corresponding with maximum and minimum thermal transfer values) achievable by the components of the first set of components. Accordingly, the upper and lower aggregated thermal energy transfer availability values may indicate a range of achievable thermal transfers.

[0167] Obtaining the aggregated thermal energy transfer availability at operation 504 may include obtaining the upper and lower aggregated thermal energy transfer availability values. Herein, the upper aggregated thermal energy transfer availability value is greater than the lower aggregated thermal energy transfer availability value.

[0168] Herein, transfers of energy to the thermal transfer fluid are represented with positive sign and transfers from the thermal transfer fluid have a negative sign, although example implementations are not limited to this convention.

[0169] An aggregated target thermal energy transfer value may be obtained for the at least one component, based on the one or more target thermal energy transfers by aggregating the target thermal energy transfers associated with the one or more components. For example, the aggregated target thermal energy transfer value may be obtained by summing the target thermal energy transfers.

[0170] An upper energy balance value may be obtained. The upper energy balance value indicating a sum of the upper aggregated thermal energy transfer availability value and the aggregated target thermal energy transfer value. Similarly, a lower energy balance value may be obtained, with the lower energy balance value indicating a sum of the lower aggregated thermal energy transfer availability value and the aggregated target thermal energy transfer value. The upper and lower energy balance values may indicate whether the overall thermal transfers that can be achieved in the thermal circuit can balance the aggregated target thermal energy transfer value. As such, the target thermal energy transfers of the at least one component may be determined to be achievable if the upper energy balance value is greater than or equal to zero and the lower energy balance value is less than or equal to zero. An energy balance of zero indicates that the achievable thermal energy transfers are able to provide the target thermal energy transfers (i.e., are able to balance the target thermal energy transfers).

[0171] A circuit error value, Ac, may be obtained by adding the smaller of the upper energy balance value, Bu, and zero to the greater of the lower energy balance value, Bl, and zero. That is, Ac = min(Bu, 0) + max(BI, 0). Accordingly, if Bl < 0 < Bu, then Ac = 0. On the other hand, if 0 < Bl < Bu, then Ac = Bl. Similarly, if Bl < Bu < 0, then Ac = Bu. Thus, the circuit error value represents the value in the range between the upper energy balance value and the lower energy balance value that is closest to 0, and so represents the smallest error possible for the thermal circuit in the thermal operating mode.

[0172] The aggregated thermal energy transfer availability of a set of components may be based on aggregating respective thermal energy transfer availability values of the components in the set. In some examples, upper and lower aggregated thermal energy transfer availability values may be determined, wherein only positive thermal energy transfer availability values contribute to the upper aggregated thermal energy transfer availability value, and only negative thermal energy transfer availability values contribute to the lower aggregated thermal energy transfer availability value.

[0173] Each component of the set of components may be associated with a thermal energy transfer capability indicative of a thermal transfer achievable by the component. The thermal energy transfer capability value may indicate a thermal energy transfer corresponding with the largest magnitude energy transfer (with the thermal transfer fluids) that the component is capable of. For example, if the component is able to transfer thermal energy to the thermal transfer fluids, the thermal energy transfer capability value may be a positive value indicating the greatest rate that the component is able to transfer thermal energy to the thermal transfer fluids. Similarly, if the component is able to receive thermal energy from the thermal transfer fluids, the thermal energy transfer capability value may be a negative value indicating the greatest rate that the component is able to transfer thermal energy from the thermal transfer fluids.

[0174] A thermal energy transfer availability value may be indicative of a thermal transfer (between the respective component and the thermal transfer fluids) beyond (in addition to) any target thermal energy transfer associated with the component. As such, for a component that is not a thermal customer, the thermal energy transfer availability value may be the thermal energy transfer capability value of the component. For a thermal customer, the thermal energy transfer availability value may be indicative of a thermal energy transfer that the component is able to provide beyond the target thermal energy transfer value. The upper aggregated thermal energy transfer availability value may be based on positive thermal energy transfer availability values of components in the set of components. Similarly, the lower aggregated thermal energy transfer availability value may be based on the negative thermal energy transfer availability values of components in the set of components. The upper aggregated thermal energy transfer availability value may be the sum of the positive thermal energy transfer availability values associated with the components of the set of components. Similarly, the lower aggregated thermal energy transfer availability value may be the sum of the negative thermal energy transfer availability values associated with the components of the set of components.

[0175] In some examples, the aggregated thermal energy transfer availability may be indicative of a range of rates at which thermal energy is transferable between the components of the set of components and the thermal transfer fluids. For example, the aggregated thermal energy transfer availability may indicate upper and lower thermal transfer rates (e.g., maximum and minimum thermal transfer rates) achievable by the components of the first set of components beyond the target thermal energy transfers associated with the components.

[0176] At operation 506 it is determined whether the target thermal energy transfers are achievable in the operating mode. This may include checking an energy balance for the operating mode by determining whether the desired (target) thermal energy transfers can be met by the thermal energy transfers that are possible in the operating mode. For example, it may be determined whether the aggregated thermal energy transfer availability is able to balance the aggregated target thermal energy transfer value.

[0177] In some examples, the determination in operation 506 may be based on a comparison between the target thermal energy transfers (or the aggregated target thermal energy transfer value) and the achievable thermal energy transfer.

[0178] Where the aggregated thermal energy transfer availability indicates a range of thermal energy transfers that are achievable in the operating mode, the determining at operation 506 may include determining whether the range of thermal energy transfers is compatible with the target thermal energy transfers. For example, the aggregated target thermal energy transfer value may be compared with the range of thermal energy transfers. In some examples, the determining in operation 506 may include determining whether the aggregated target thermal energy transfer value is balanced by a thermal energy transfer value within the range of thermal energy transfers. If the aggregated target thermal energy transfer value is balanced by a value in the range of thermal energy transfers, it indicates that, for the set of components, the operating mode is able to perform the desired transfers of thermal energy.

[0179] Where the target thermal energy transfers and aggregated thermal energy transfer availability are indicated as rates of thermal energy transfer, the range of thermal energy transfers corresponds with a range of rates, and the aggregated target thermal energy transfer value corresponds with an aggregated target thermal energy transfer rate.

[0180] The operations 502, 504 and 506 may be performed for each thermal circuit in each operating mode to be considered. Accordingly, it can be determined, for each thermal circuit of each operating mode whether target thermal energy transfers associated with each respective thermal circuit are achievable in each respective operating mode.

[0181] In more detail, each operating mode of the thermal management system 100 may define one or more thermal circuits, each thermal circuit comprising a subset of components that are in thermal communication with each other via a respective subset of thermal transfer fluids. According to examples, the method comprises, for each thermal circuit in each of the one or more operating modes: obtaining, for at least one component in the respective subset of components, a respective target thermal energy transfer between the component and the respective subset of thermal transfer fluids in the thermal circuit in the operating mode. An aggregated thermal energy transfer availability is obtained for the respective subset of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective subset of components is collectively able to exchange with the respective subset of thermal transfer fluids in the thermal circuit in the operating mode. Accordingly, it may be determined, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the thermal circuit in the operating mode.

[0182] Herein a subset of a set may refer to a proper subset, i.e. a subset that does not include all of the elements of the set, or to an improper subset, i.e. a subset that includes all of the elements of the set.

[0183] In some examples, the first subset of components associated with a first operating mode may have one or more components in common with a second subset of components associated with a second operating mode. In some examples, the first and second subsets of components have no components in common. In some examples, all components in the first subset of components may be included in the second subset of components. In some examples, at least one of: the first subset of components includes at least one component that is not in the second subset of components, and the second subset of components includes at least one component that is not in the first subset of components. The components of the first subset may contain the components in a thermal circuit of the first operating mode, and the second subset may contain the components of a thermal circuit of the second operating mode.

[0184] In some examples, the suitability of an operating mode is dependent on the performance of each thermal circuit of the operating mode. As such, assessing the performance of the operating mode may take into account whether all of the target thermal energy transfers in all of the thermal circuits of the operating mode are achievable.

[0185] As such, in some examples it is determined whether all target thermal energy transfers of the thermal management system 100 are achievable in each respective operating mode, based on the determination, for each of the one or more thermal circuits defined by the operating mode, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the operating mode. An operating mode may be determined to be able to satisfy all of the target thermal energy transfers of the thermal management system if each thermal circuit of the operating mode is determined to be able to satisfy all of the target thermal energy transfers of the components in that thermal circuit.

[0186] One or more outputs may be provided to indicate the result of the determining whether all target thermal energy transfers of the thermal management system 100 are achievable in each respective operating mode. In some examples, where one or more thermal circuits of the operating mode do not satisfy their associated target thermal energy transfers, the output may be indicative of an overall error value, indicative of the aggregated error across all of the thermal circuits. In some examples, the aggregated error is the sum of the absolute values of the respective error values associated with the thermal circuits. The components of different thermal circuits are not in thermal communication, and so a thermal energy excess in one thermal circuit is not balanced, or ameliorated, by a thermal energy deficit in another thermal circuit. Other approaches could also be used to determine the aggregated error. For example, squared values of the respective error values may be summed. In some examples, weights may be applied to the errors associated with certain thermal circuits when aggregating the error values. For example, error values associated with thermal circuits containing particular components may be weighted to increase or decrease their relative contribution to the aggregated error, e.g., in order to prioritise temperature adjustment of some components relative to others.

[0187] An output of an overall error value of zero may be indicative of an operating mode that is able to achieve all of the target thermal energy transfers in each of its thermal circuits.

[0188] FIG. 6 illustrates an example of an algorithm 600 to determine whether the target thermal energy transfer is achievable in a thermal circuit of a particular operating mode. In this example, the thermal circuit corresponds with the second thermal circuit 402b of FIG. 4A. The thermal circuit includes the front electric drive unit 202a, rear electric drive unit 202b and second heat exchanger 308. In this thermal circuit the front electric drive unit 202a and rear electric drive unit 202b are thermal customers that are designated as thermal storage components. The second heat exchanger 308 is the radiator and is not a thermal customer.

[0189] Block 602 indicates obtaining the target thermal energy transfers associated with the front electric drive unit 202a and rear electric drive unit 202b. Block 604 indicates the target thermal energy transfer for the front electric drive unit 202a, and block 606 indicates the target thermal energy transfer for the rear electric drive unit 202b. When the front electric drive unit 202a is above its target operating temperature range, block 604 will indicate a positive value (indicating a request to transfer thermal energy from the front electric drive unit 202a), when the front electric drive unit 202a is below its target operating temperature range block 604 will indicate a negative value (indicating a request to transfer thermal energy to the front electric drive unit 202a). When the front electric drive unit 202a is within its target operating temperature range, block 604 will have a value of zero, since the front electric drive unit 202a does not have a demand for a thermal energy transfer. Block 606 similarly indicates a positive number, a negative number, or zero, depending on whether the rear electric drive unit 202b is, respectively, above, below or within its target operating temperature range.

[0190] The values indicated by the blocks 604 and 606 may represent the target rate of thermal energy transfer. In this example, when the values are nonzero the values may indicate an energy transfer rate corresponding with a 1 degree / minute change in temperature of, respectively, the front and rear electric drive units. In this example, the target rate of thermal energy transfer may be obtained from a lookup table that indicates target thermal energy transfer rates for each thermal customer.

[0191] At block 608 the target thermal energy transfer values in blocks 604 and 606 are summed to produce the aggregated target thermal energy transfer rate for the thermal circuit.

[0192] Block 610 indicates obtaining thermal energy transfer availability values associated with the components of the thermal circuit. Blocks 612, 614, and 616 respectively indicate thermal energy transfer availability values associated with front electric drive unit 202a, rear electric drive unit 202b, and second heat exchanger 308. The thermal energy transfer availability value associated with the second heat exchanger 308 may be the thermal energy transfer capability value of the second heat exchanger 308, and may be based on, for example, a temperature of the coolant and an ambient temperature. In some examples, the thermal energy transfer availability value of the second heat exchanger 308 may be obtained from a lookup table, e.g., based on a temperature difference between the coolant and the surroundings. In operating modes where the second heat exchanger 308 is bypassed, the thermal energy transfer availability value for the second heat exchanger 308 may be zero, as the second heat exchanger 308 does not take part in thermal energy transfer in such modes. Similarly, in an operating mode in which the coolant heater 304 does not operate, a thermal circuit of that operating mode that includes coolant heater 304 may have a thermal energy transfer capability value for the coolant heater 304 of zero, since the coolant heater 304 does not participate in thermal energy transfer in that operating mode.

[0193] Block 618 indicates that the thermal energy transfer availability values of each of blocks 612, 614, and 616 are passed to block 620.

[0194] Block 620 aggregates the thermal energy transfer availability values to obtain upper and lower aggregated thermal energy transfer availability values. Only positive thermal energy transfer availability values contribute to the upper aggregated thermal energy transfer availability value, and only negative thermal energy transfer availability values contribute to the lower aggregated thermal energy transfer availability value. This is shown in FIG. 6 as providing each of the thermal energy transfer availability values to each of blocks 624 and 626. Block 624 selects only positive values of the input values (by comparing each thermal energy availability with zero, which is shown at block 622, and taking the higher of the two values). The results of the comparisons for each of the three thermal energy transfer availability values (either the original value or zero) are summed at block 628, to produce the upper aggregated thermal energy transfer availability value.

[0195] Similarly, block 626 compares each of the thermal energy transfer availability values with 0 and takes the minimum of each respective comparison. The resulting values are summed at block 630. Accordingly, the output of block 630 is the sum of the negative thermal energy transfer availability values.

[0196] Block 632 combines the aggregated target thermal energy transfer rate obtained at block 608 with the upper and lower aggregated thermal energy transfer availability values obtained at 628 and 306. In the example of FIG. 6, block 634 adds the aggregated target thermal energy transfer rate and the upper aggregated thermal energy transfer availability value to produce an upper energy balance value. Similarly, block 632 adds the aggregated target thermal energy transfer rate and the lower aggregated thermal energy transfer availability value to produce the lower energy balance value.

[0197] Block 638 determines whether zero is between the upper and lower energy balance values, calculated by blocks 634 and 636, and determines the circuit error value. According to the arrangement of FIG. 6, block 642 compares the upper energy balance value output of block 634 with zero (illustrated as block 640), and outputs the minimum value of the two values (the lower of the two values). Accordingly, if the upper energy balance value output by block 634 is positive, block 642 will output zero. On the other hand, if the upper energy balance value is negative, block 642 will output the same value as block 634 (i.e. the upper energy balance value).

[0198] Similarly, block 644 compares the output of block 636 with zero (illustrated as block 640), and outputs the maximum value of the two values (the higher of the two values). Accordingly, if the lower energy balance value output by block 636 is negative, block 644 will output zero. On the other hand, if the lower energy balance value is positive, block 644 will output the same value as block 636 (i.e., the lower energy balance value).

[0199] The outputs of blocks 642 and 644 are summed at block 646. If the upper and lower energy balance values have opposite signs (or either is zero), i.e., if zero is between the two values, the output of both of blocks 642 and 644 will be zero, such that the result of the sum at 646 is zero. This indicates that the target thermal energy transfers are achievable in the thermal circuit in the operating mode under consideration. The output by block 646 corresponds with the circuit error value. A circuit error value of zero indicates that the target thermal energy transfers are achievable in the respective thermal circuit in the operating mode under consideration. A nonzero value indicates that the target thermal energy transfers are not achievable.

[0200] On the other hand, if both upper and lower energy balance values are positive, zero is not between the two values, indicating that the available thermal energy transfers indicated by blocks 612, 614, and 616 are not able to remove thermal energy at a rate that meets the target thermal energy transfers indicated in blocks 604 and 606. In this case, the output of block 644 will be a positive number, while the output of block 642 will be zero, and so the sum at 646 will result in positive number. The positive number output by block 646 corresponds with the circuit error value. The positive circuit error value indicates that a target rate of removal of heat from the thermal customers cannot be met in the respective thermal circuit in the operating mode under consideration.

[0201] Similarly, if both upper and lower energy balance values are negative, zero is not between the two values, indicating that the available thermal energy transfers indicated by blocks 612, 614, and 616 are not able to supply thermal energy at a rate that meets the target thermal energy transfers indicated in blocks 604 and 606. In this case, the output of block 642 will be a negative number, while the output of block 644 will be zero, and so the sum at 646 will result in negative number. The negative number output by block 646 corresponds with the circuit error value. The negative circuit error value indicates that a target rate of supplying heat to the thermal customers cannot be met in the respective thermal circuit in the operating mode under consideration.

[0202] A result of the algorithm 600 may be output at 648. In some examples the result of the sum at block 646 may be output, indicating the circuit error value, as described above.

[0203] Accordingly, an achievable thermal energy transfer may be determined based on aggregating potential sources or sinks of thermal energy. Assessing whether thermal energy transfers requested by components are achievable in an operating mode may include assessing thermal energy transfer requirements and achievable thermal energy transfers for each thermal circuit of the operating mode separately, as each thermal circuit may be considered to be thermally isolated from the other thermal circuits.

[0204] As described in relation to FIG. 4A to FIG. 4F, each operating mode may be associated with a respective set of thermal circuits, each thermal circuit comprising a group of the components that are in mutual thermal communication via the thermal management system 100 in the operating mode. Comparing the thermal energy transfer requirement with an achievable thermal energy transfer in an operating mode may include determining, for each thermal circuit in the set of thermal circuits associated with the operating mode, whether an achievable thermal energy transfer in the thermal circuit is consistent with thermal energy transfer requirements of components in the thermal circuit. The operating mode may be determined to comply with the thermal energy transfer requirement if it is determined that the achievable thermal energy transfer in each thermal circuit of the operating mode is consistent with the thermal energy transfer requirements in each respective thermal circuit. In some examples, the operating mode may be determined not to comply with the thermal energy transfer requirement if it is determined that, for any thermal circuit of the operating mode the achievable thermal energy transfer in that thermal circuit of the operating mode is not consistent with the thermal energy transfer requirements in that thermal circuit.

[0205] FIG. 7 shows a method 700 for obtaining a thermal energy transfer availability value for a thermal customer. The thermal customer may be the front electric drive unit 202a, for example, although the method may be used for other thermal customers. At block 702 a target thermal energy transfer and a thermal energy transfer capability value for the thermal customer are obtained. The thermal energy transfer capability value may indicate a fastest rate at which the thermal customer is able to transfer thermal energy to or from the thermal transfer fluids. Here the fastest rate is the thermal transfer, within the thermal customer's range of possible thermal transfers, having the greatest absolute value. However, it is to be noted that the thermal energy transfer capability value is a signed value (e g., is negative for transfers from the thermal transfer fluids and is positive for transfers to the thermal transfer fluid).

[0206] At block 704 it is determined whether the target thermal energy transfer is zero. If the target thermal energy transfer is zero, the thermal customer is within its target operating temperature range and so the thermal customer does not request a transfer of thermal energy. In this case, the method proceeds to block 706, where the thermal energy transfer availability value is set to be the thermal energy transfer capability value, since the full transfer capability of the thermal customer can be used to balance thermal energy transfers requested by other components of the thermal circuit. Put another way, as the thermal customer does not request a thermal energy transfer, all of the thermal energy transfer capability is in excess of the thermal energy transfer to or from the thermal customer to meet its target thermal energy transfer (which is zero). The thermal energy transfer availability value is output at block 716.

[0207] If, at block 704, the target thermal energy transfer is not zero, the method proceeds to block 708, where it is determined whether the target thermal energy transfer is greater than zero. This indicates that the thermal customer is above its target operating temperature range (i.e. , too hot). If, at block 704, the target thermal energy transfer is greater than zero the method proceeds to 718. Otherwise, the method proceeds to block 710 (i.e., if the target thermal energy transfer is less than zero, indicating that the thermal customer is too cool).

[0208] At block 718 (i.e., when the target thermal energy transfer is greater than zero), it is determined whether the thermal energy transfer capability value minus the target thermal energy transfer is greater than zero. If the thermal energy transfer capability value minus the target thermal energy transfer is greater than zero, the method proceeds to block 720, where the thermal energy transfer availability value is set equal to the thermal energy transfer capability value minus the target thermal energy transfer. If the method reaches block 720, both the target thermal energy transfer and the thermal energy transfer capability value are greater than zero, and the thermal energy transfer capability value is greater than the target thermal energy transfer. Accordingly, the thermal customer can transfer thermal energy at the target rate, or faster, in the correct direction (i.e., to the thermal transfer fluids), and is able to transfer thermal energy to the thermal transfer fluids at a greater rate than the target rate, if needed to meet the thermal energy transfer requirements of other components of the thermal circuit. The additional capacity for thermal energy transfer, beyond the target thermal energy transfer of the thermal customer, corresponds with the thermal energy transfer capability value minus the target thermal energy transfer, as calculated at block 720. This is a positive value (as the thermal energy transfer capability value is greater than the target thermal energy transfer), corresponding with the capacity for an additional thermal energy transfer to the thermal transfer fluids from the thermal customer. The thermal energy transfer availability value is output at block 716.

[0209] If, at block 718, it is determined that the thermal energy transfer capability value minus the target thermal energy transfer is not greater than zero, it indicates that the thermal customer is not able to transfer thermal energy to the thermal transfer fluids at the rate indicated by the target thermal energy transfer, and so does not have capacity to transfer thermal energy more quickly than the target thermal energy transfer. Accordingly, the thermal energy transfer availability value is set to 0 at block 722. The thermal energy transfer availability value is output at block 716.

[0210] At block 710 (i.e. , when the target thermal energy transfer is less than zero), it is determined whether the thermal energy transfer capability value minus the target thermal energy transfer is less than zero. If the thermal energy transfer capability value minus the target thermal energy transfer is less than zero, the method proceeds to block 712, where the thermal energy transfer availability value is set equal to the thermal energy transfer capability value minus the target thermal energy transfer. If the method reaches block 712, both the target thermal energy transfer and the thermal energy transfer capability value are less than zero, and the thermal energy transfer capability value is less than (i.e., more negative than) the target thermal energy transfer. Accordingly, the thermal customer can transfer thermal energy at the target rate, or faster, in the correct direction (i.e., from the thermal transfer fluids), and is able to transfer thermal energy from the thermal transfer fluids at a greater rate, if needed to meet the thermal energy transfer requirements of other components of the thermal circuit. The additional capacity for thermal energy transfer, beyond the target thermal energy transfer of the thermal customer, corresponds with the thermal energy transfer capability value minus the target thermal energy transfer, as calculated at block 712. This is a negative value (as the thermal energy transfer capability value is more negative than the target thermal energy transfer), corresponding with the capacity for an additional thermal energy transfer from the thermal transfer fluids. The thermal energy transfer availability value is output at block 716.

[0211] If, at block 710, it is determined that the thermal energy transfer capability value minus the target thermal energy transfer is not less than zero, it indicates that the thermal customer is not able to transfer thermal energy from the thermal transfer fluids at the rate indicated by the target thermal energy transfer, and so does not have capacity to transfer thermal energy more quickly than the target thermal energy transfer. Accordingly, the thermal energy transfer availability value is set to 0 at block 714. The thermal energy transfer availability value is output at block 716.

[0212] Examples have been provided in which the target thermal energy transfers and aggregated thermal energy transfer availabilities are indicated as rates of transfer of thermal energy. However, other possibilities exist. For example, target thermal energy transfers and aggregated thermal energy transfer availabilities may be expressed as amounts of thermal energy to be transferred. For example, a target thermal energy transfer of a component may be indicative of an amount of thermal energy the component should gain or lose in order to be within its target operating temperature range, e.g., may be expressed in Joules or other units of energy. Similarly, the thermal energy transfer capability value of a component may indicate an amount of energy that can be provided to or removed from the thermal transfer fluids. In the case of a component that can continuously transfer thermal energy with the thermal transfer fluids, such as coolant heater 304, or second heat exchanger 308, the amount of energy may be based on the energy transfer in a particular unit of time. In the case of a thermal customer, the thermal energy transfer availability value may be indicative of the capacity of the thermal customer to act as a source or sink while remaining within its target operating temperature range. Where a thermal customer is not in its target operating temperature range, the thermal energy transfer availability value may be based on the amount of thermal energy that is transferable when the temperature of the thermal customer is at the limit of the target operating temperature range that is closest to its current temperature.

[0213] Therefore, thermal energy transfer requirements may indicate one or more of respective amounts of thermal energy transfer requested by respective components requesting thermal energy transfers, and respective rates of transfer of thermal energy requested by respective components requesting thermal energy transfers. Accordingly, the thermal energy transfer requirement for a component may include at least one of: an indication of a rate of thermal energy to be supplied to the component, a rate of thermal energy to be extracted from the component, an indication of an amount of thermal energy to be supplied to the component, or an indication of an amount of thermal energy to be extracted from the component.

[0214] As noted above, target thermal energy transfers and aggregated thermal energy transfer availabilities, etc. may be expressed in terms of temperatures.

[0215] In some examples, a recommended operating mode may be selected from among compatible operating modes. The recommended operating mode may be an operating mode to be implemented in the thermal management system 100. As described above, a compatible operating mode is a mode that is able to provide thermal energy to each component that has a deficit of thermal energy and is able to extract thermal energy from each component that has excess thermal energy. That is, determining compatible operating modes may be based on determining whether the operating mode heats all thermal customers that are too cool (i.e. have a temperature below their target operating temperature range) and cools all thermal customers that are too hot (i.e. have a temperature above their target operating temperature range). A compatible operating mode may be an operating mode that additionally does not transfer thermal energy to or from a thermal customer that is indicated as not to provide or receive thermal energy (e.g., where the thermal customer is in its target operating temperature range and is not designated as a thermal storage component).

[0216] The determination of whether an operating mode is a compatible operating mode may be based on directions of energy transfer between the components and the thermal transfer fluids, and may be independent of the magnitude of the thermal energy transfers. Accordingly, determining whether an operating mode is a compatible operating mode may be simpler than determining whether the operating mode satisfies current target thermal energy transfers of the components of the electric vehicle 200.

[0217] The compatible operating modes may be determined, and the recommended operating mode may be selected from among the compatible operating modes, based at least in part on the determination in operation 506 whether the target thermal energy transfers are achievable in the operating mode.

[0218] Selecting the recommended operating mode may include evaluating each operating mode from among the compatible operating modes and selecting the recommended operating mode based on the evaluation. Evaluating an operating mode may include evaluating whether the operating mode is consistent with indicated thermal energy transfer requirements (e.g., with target rates or magnitudes of thermal energy transfers indicated by the thermal energy transfer requirements), and may additionally include one or more of: evaluating a degree to which the operating mode is consistent with the thermal energy transfer requirements, and evaluating an energy cost associated with the operating mode. The energy cost may be based on one or more of: an energy usage associated with the operating mode, and thermal energy transferred to the environment according to the operating mode, for example.

[0219] In some examples, the evaluating may include assessing an energy cost associated with at least some compatible operating modes, in addition to assessing whether thermal energy transfers requested by thermal customers are achievable in the compatible operating modes.

[0220] Where it is determined whether an operating mode is a compatible operating mode before performing an evaluation of the operating mode, the evaluating may be avoided for operating modes that are not compatible operating modes. Put another way, in some examples the evaluating may be carried out only for operating modes that are determined to be compatible operating modes.

[0221] In some examples, evaluating a compatible operating mode may use more computing resource (e.g., memory, processor cycles, etc.) than determining whether the operating mode is a compatible operating mode. Accordingly, the (relatively) computationally demanding evaluation of an operating mode may be avoided for operating modes that do not provide heat to thermal customers that are below their target operating temperature range, and remove heat from thermal customers that are above their target operating temperature range.

[0222] In some examples, selecting the recommended operating mode comprises evaluating each operating mode from among the compatible operating modes and selecting the recommended operating mode based on the evaluation. For one or more of the compatible operating modes the evaluating may comprise obtaining an energy cost associated with a respective operating mode of the one or more of the compatible operating modes. These examples may be particularly suitable for rapidly considering a large number of operating modes in order to select an operating mode to be implemented. This may be particularly beneficial for real-time use in a vehicle with limited on-board computing resources, but other possibilities are also contemplated.

[0223] In some examples, the selection of an operating mode may be repeated during operation of the electric vehicle 200 (e.g., while the electric vehicle 200 is driving) in order to reassess whether the current operating mode is still a desired operating mode. For example, the selection may be repeated at regular intervals (along with preceding steps, such as obtaining an updated set of compatible operating modes and re-evaluating the compatible operating modes) to select an operating mode, the intervals may correspond with a time step of the vehicle control system, for example, but the duration of the intervals is not particularly limited. In some examples, the selecting may be performed in response to other triggers instead of, or in addition to, periodically. For example, the selecting may be performed in response to a change in situation of the electric vehicle 200, such as a change in driving mode, based on a change in average driving speed, etc. Similarly, the selecting may be performed, for example, if it is determined that the battery 204 is to be preconditioned, that is, heated in preparation for charging.

[0224] Determining whether target thermal energy transfers are achievable in an operating mode may be performed before energy costs associated with the mode are obtained. For example, operating modes may be indicated as accepted or rejected based on the whether or not the target thermal energy transfers are achievable in the respective operating mode. In this case, the accepted operating modes include the one or more operating modes for which energy costs are to be determined. Accordingly, the rejection of operating modes on the basis of whether the target thermal energy transfers are achievable allows elimination of operating modes before obtaining the associated energy cost, so the determination of the energy cost associated with rejected operating modes may be avoided. This may improve computational efficiency, particularly where obtaining an energy cost associated with an operating mode uses more computing resource than determining whether an operating mode is accepted or rejected. In some examples, the energy cost is not obtained for rejected operating modes.

[0225] FIG. 8 illustrates a method 800 according to some examples. Information on an operating state of the electric vehicle 200, such as the temperature of components of the electric vehicle 200, is obtained at block 802. In addition, operating mode information is received at block 802, the operating mode information indicating available operating modes and the properties of those operating modes, e.g., describing the thermal circuits in the operating mode, components in the respective thermal circuits, activation states of components in the operating mode, etc.

[0226] At block 804 a first operating mode is selected as the current operating mode for consideration. In some examples, the selection may be arbitrary, e.g., based on a predetermined ordering of the operating modes. At block 806 it is determined whether a current operating mode is a compatible operating mode. If the operating mode is a compatible operating mode the method proceeds to block 808, where it is determined whether the current operating mode satisfies the thermal energy transfer requirements (e.g., whether all of the target thermal energy transfers are achievable in all of the thermal circuits in the current operating mode). If the current operating mode is determined to satisfy the thermal energy transfer requirements, the method proceeds to block 810, where an energy cost for the current operating mode is determined. The method then proceeds to block 812. The method also proceeds to block 812 if it is determined at block 806 that the current operating mode is not a compatible operating mode. Similarly, the method proceeds to block 812 if is determined at block 808 that the current operating mode does not satisfy the one or more thermal energy transfer requirements. At block 812 it is determined whether there are any further operating modes. If there are further operating modes to consider the method proceeds to block 814, where the next operating mode is selected as the current operating mode for consideration, and the method returns to block 806. The selection of the next operating mode to consider is not particularly limited, and may be arbitrary (e.g., by selecting a next operating mode from a predetermined, ordered list of operating modes). If, at block 812, it is determined that all operating modes that are to be considered have been considered, the method proceeds to block 816, where a recommended operating mode is selected. The recommended operating mode may be selected from among the operating modes for which an energy cost was determined. In some examples, the operating mode having the lowest cost may be selected as the recommended operating mode. In some examples, the recommended operating mode may be selected based on a cost function, where the cost function is based on the energy cost of the operating mode, and possibly other factors.

[0227] In some examples, where no energy costs are determined, for example where none of the operating modes are determined at block 808 to satisfy the one or more thermal energy transfer requirements, an operating mode may be selected at block 816 based on the performance of the operating modes with respect to the one or more thermal energy transfer requirements (e.g., based on overall error values determined for the operating modes). For example, an operating mode that best meets (e.g. comes closest to satisfying) the one or more thermal energy transfer requirements may be selected as the recommended operating mode, this may be an operating mode having the lowest overall error value among the operating modes.

[0228] According to the example of FIG. 8, determining whether the operating mode satisfies the one or more thermal energy transfer requirements may be avoided for operating modes that are not compatible operating modes. Similarly, the energy cost determination may be avoided for operating modes that do not satisfy the one or more thermal energy transfer requirements. This leads to an efficient selection of a recommended operating mode based on various considerations, such as a suitability of the operating mode and an energy cost associated with the operating mode.

[0229] In some examples, the determination of an energy cost associated with an operating mode may require more computing resource (on average) than determining whether the operating mode satisfies the one or more thermal energy transfer requirements. Similarly, determining whether the operating mode satisfies the one or more thermal energy transfer requirements may require more computing resource (on average) than determining whether an operating mode is a compatible operating mode. In such a case, the method 800 of FIG. 8 may be particularly efficient.

[0230] The energy cost may indicate one or more of: an energy requirement to transition to the respective operating mode, an energy requirement to operate the thermal management system 100 in the respective operating mode, and heat energy transferred off the vehicle in that operating mode. For example, the energy cost associated with an operating mode may comprise one or more of a thermal energy cost value representing an amount of thermal energy transferred off the vehicle in that operating mode and an actuator energy cost value representing an energy cost associated with operating the thermal management system 100 in that operating mode.

[0231] The actuator energy cost value associated with an operating mode may be representative of at least one of: an energy cost of operating a compressor according to that operating mode; a valve actuation energy cost associated with that operating mode; a vehicle drag cost associated with operation of a heat exchanger according to that operating mode (e g., vehicle drag associated with active vane management); an energy cost of operating a pump according to that operating mode; and an energy cost of operating a fan according to that operating mode.

[0232] The energy cost may, for example, be obtained from a lookup table, or by using a model of the thermal management system 100.

[0233] In some examples, the actuator energy cost may include any energy associated with operating the thermal management system 100, for example an energy cost required to operate the compressor of the refrigerant circuit 408 to provide refrigerant to the first heat exchanger 306, or a drag cost associated with providing airflow to the outside heat exchanger. Examples of actuator energy costs associated with an operating mode may include: an energy cost of operating a compressor according to that operating mode; a valve actuation energy cost associated with that operating mode; a vehicle drag cost associated with operation of a heat exchanger according to that operating mode; an energy cost of operating a pump according to that operating mode; and an energy cost of operating a fan according to that operating mode. Certain actuators in the thermal management system 100, for example pumps, compressors, fans, etc., may have an associated duty cycle or activation level setting to satisfy the thermal energy transfer requirements of the components when the thermal management system 100 is operating in a particular operating mode. Energy costs for actuators may be further calculated based on the duty cycle to provide a more accurate determination of the energy associated with operating the actuator.

[0234] The energy cost for each operating mode may be determined using a predictive model of the thermal management system 100. In embodiments, the predictive model of the thermal management system 100 may comprise a plurality of predictive models each associated with a respective subcomponent of the thermal management system 100. Thus, each actuator energy cost may be calculated using a model of the respective actuator that defines a relationship between one or more operating parameters of the thermal management system 100 and an energy cost associated with the actuator. For example, a predictive model for the compressor of the refrigerant circuit 408 may allow an energy cost of operating the compressor to be determined based on certain operating parameters, such as the duty cycle. Each model may be determined empirically or through simulation of the thermal management system 100 and climate control system 104. In some embodiments, a model for each actuator may be stored as a look up table (LUT) associating one or more operating parameters of the actuator with an associated actuator energy cost.

[0235] Similarly, predictive models may be provided for the first and second heat exchangers and for an outer heat exchanger of the refrigerant circuit 408 to allow the thermal energy to be transferred off the vehicle to the outside environment to be determined based on one or more measured parameters. For example, heat rejected to the outside environment by the second heat exchanger 308 may be predicted based on one or more of: an ambient temperature of the outside environment; a flow rate and / or temperature of coolant through the second heat exchanger 308; an operating state of a fan associated with the second heat exchanger 308, etc.

[0236] In embodiments, the actuator energy cost for an operating mode may be determined by summing all of the actuator energy costs associated with operating the thermal management system 100 in that operating mode to meet the thermal transfer requirements of the components. The energy cost associated with the operating mode may then be calculated by summing the actuator energy cost with the total amount of thermal energy transferred off the vehicle via the second heat exchanger 208 and the outside heat exchanger of the refrigerant circuit 408.

[0237] By assessing energy costs associated with respective operating modes, the selection of an operating mode can improve energy efficiency compared to temperature based approaches, for example by avoiding operating modes that have a high energy cost. This may reduce the amount of energy that would otherwise be drawn from the traction battery, resulting in increased range and a corresponding improved user experience.

[0238] Further, by determining an energy cost associated with transitioning to and / or maintaining an operating mode, such as energy to be supplied to actuators, heating elements, compressors, etc. it is possible to select an operating mode that helps to avoid unnecessary energy use.

[0239] In some examples, the energy cost may be based, in part on state indications in the operating mode information. The state indications may be used to determine which components are active in the operating mode, and so may contribute to the energy cost. For example, heaters, compressors, etc., that may be active and have an associated energy cost when active and may be indicated as active or inactive in the state information.

[0240] By taking a whole system energy based approach for multiple components of the vehicle while taking into account thermal requirements of those components, the amount of thermal energy retained on the vehicle for use by other systems and components may be maximised, or at least substantially increased, compared to temperature based approaches, for example by avoiding rejecting, to an external environment, heat generated in a fraction battery during operation that could usefully be transferred to another system such as a climate control system 104. This increase in retained thermal energy may reduce the amount of electrical energy that would otherwise be drawn from the fraction battery to provide heat energy for those other systems, increasing efficiency with which energy is used on the electric vehicle, resulting in increased range and a corresponding improved user experience. By assessing the energy costs associated with various operating modes, it is possible to avoid selection of modes that are associated with unnecessarily high energy costs, providing improved efficiency. Moreover, by determining compliance of various operating modes with thermal energy transfer requirements, the effectiveness of the thermal management system 100 may be maintained.

[0241] In alternative arrangements, an assessment of energy transfer rates / amounts may be carried out before determining compatible operating modes, such that rejected modes are determined before compatible operating modes, and the compatible operating modes are selected from modes that are not rejected. The selection of a recommended operating mode may then be performed, for example, on the basis of energy costs associated with the compatible operating modes. In other examples, a set of operating modes may be selected on the basis of energy costs of the operating modes and compatible operating modes selected from the set of operating modes. A recommended operating mode may then be selected from the compatible operating modes, e.g., based on energy transfer rates / amounts.

[0242] In some examples, each stage may happen in turn. For example, in the method 800 of FIG. 8, a list of compatible operating modes may be determined, followed by acceptance or rejection of operating modes based on an amount / rate of thermal energy transfer, followed by a selection of an operating mode based on energy costs. Each stage may complete before the next begins, such that the complete list of compatible operating modes is determined before carrying out the assessment based on amount / rate of thermal energy transfer. This assessment may be completed before the energy costs associated with the operating modes are determined. Alternatively, the stages may be performed in parallel. For example, when a mode is determined to be a compatible operating mode, the assessment based on amount / rate of thermal energy transfer may be performed immediately (or may be immediately queued for performance), while other operating modes continue to be assessed with regard whether or not they are compatible operating modes. Similarly, when an operating mode is determined to comply with the amount / rate of thermal energy transfer, the energy cost associated with that operating mode may be determined immediately (or may be immediately queued for determination), while the assessment of other operating modes with regard to amount / rate of thermal energy transfer continues to be assessed.

[0243] In some examples the method may include determining one or more unavailable operating modes and excluding these from consideration. For example, the outside heat exchanger may not function below a certain temperature. In such a case, when it is determined that the outside heat exchanger does not function, e.g., due to very a low temperature, operating modes that use the outside heat exchanger may be omitted from consideration. More generally, if a condition is met that is determined to render an operating mode unavailable, the operating mode may be removed from consideration. In some examples, the determination of unavailable operating modes may be performed before determining compatible operating modes (e.g., operation 806 of FIG. 8). However, other possibilities are also envisaged.

[0244] Certain methods and systems as described herein may be implemented by one or more processors that process program code that is retrieved from a storage medium, such as non-fransitory storage medium. FIG. 9 shows an example of a device 900 comprising a computer-readable storage medium (e.g. memory device 110) coupled to at least one processor 108. The computer-readable medium 110 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 medium 110 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.

[0245] In FIG. 9, the computer-readable storage medium 110 comprises program code 112 to perform a method 500 for controlling a thermal management system 100 of an electric vehicle corresponding to the embodiment shown in FIG. 5, that is, where the thermal management system 100 has a plurality of operating modes, and wherein in each operating mode the thermal management system 100 is configured to transfer thermal energy among a respective set of components of the electric vehicle via one or more thermal transfer fluids, the method comprises, for one or more of the operating modes: obtaining, for at least one component in the respective set of components, a respective target thermal energy transfer between the component and the one or more thermal transfer fluids; obtaining an aggregated thermal energy transfer availability for the respective set of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective set of components is collectively able to exchange with the one or more thermal transfer fluids in the operating mode; and determining, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of the at least one component in the respective set of components are achievable in the operating mode.

[0246] The device 900 may be included in controller 106 of an electric vehicle 200, as illustrated in FIG. 2, for example.

[0247] It will be appreciated that various changes and modifications can be made to the embodiments of the present invention without departing from the scope of the present application.

Claims

CLAIMS1 . A method for controlling a thermal management system of an electric vehicle, wherein the thermal management system has a plurality of operating modes, and wherein in each operating mode the thermal management system is configured to transfer thermal energy among a respective set of components of the electric vehicle via one or more thermal transfer fluids, the method comprising, for one or more of the operating modes: obtaining, for at least one component in the respective set of components, a respective target thermal energy transfer between the component and the one or more thermal transfer fluids; obtaining an aggregated thermal energy transfer availability for the respective set of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective set of components is collectively able to exchange with the one or more thermal transfer fluids in the operating mode; and determining, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of the at least one component in the respective set of components are achievable in the operating mode.

2. The method of claim 1 , wherein each of the target thermal energy transfers corresponds with a target rate of transfer of thermal energy between the respective component and the one or more thermal transfer fluids.

3. The method of claim 1 or 2, wherein the aggregated thermal energy transfer availability corresponds with a rate at which thermal energy is transferrable, by the components of the set of components, to or from the one or more thermal transfer fluids.

4. The method of any one of claims 1 to 3, wherein the aggregated thermal energy transfer availability is indicative of a range of rates at which thermal energy is transferrable between components in the set of components and the one or more thermal transfer fluids, the target thermal energy transfers are indicative of a target rate of transfer of thermal energy between the at least one component and the one or more thermal transfer fluids, and determining whether target thermal energy transfers in the set of components are achievable in the operating mode comprises determining whether the range of rates is compatible with the target rate of transfer of thermal energy.

5. The method of claim 4, wherein the method includes aggregating the target thermal energy transfers of the one or more components to obtain an aggregated target thermal energy transfer rate for the set of components, and wherein the range of rates is determined to be compatible with the target rate of transfer of thermal energy if the aggregated target thermal energy transfer rate is balanced by a rate within the range of rates.

6. The method of any one of claims 1 to 5, wherein obtaining an aggregated thermal energy transfer availability comprises: obtaining upper and lower aggregated thermal energy transfer availability values indicative of a range of achievable thermal transfers, the upper aggregated thermal energy transfer availability value being greater than the lower aggregated thermal energy transfer availability value.

7. The method of claim 6, comprising: obtaining an aggregated target thermal energy transfer value for the at least one component, based on the one or more target thermal energy transfers; obtaining an upper energy balance value indicative of a sum of the upper aggregated thermal energy transfer availability value and the aggregated target thermal energy transfer value; and obtaining a lower energy balance value indicative of a sum of the lower aggregated thermal energy transfer availability value and the aggregated target thermal energy transfer value, wherein the target thermal energy transfers of the at least one component are determined to be achievable if the upper energy balance value is greater than or equal to zero and the lower energy balance value is less than or equal to zero.

8. The method of claim 6 or 7, wherein: each component of the set of components has an associated thermal energy transfer availability value indicative of a thermal transfer, between the respective component and the thermal transfer fluids, beyond any target thermal energy transfer associated with the component; the upper aggregated thermal energy transfer availability value is based on positive thermal energy transfer availability values, and the lower aggregated thermal energy transfer availability is based on negative thermal energy transfer availability values.

9. The method of any one of claims 1 to 8, wherein each operating mode of the thermal management system defines one or more thermal circuits, each thermal circuit comprising a subset of components that are in thermal communication with each other via a respective subset of thermal transfer fluids, and wherein the method comprises, for each thermal circuit in each of the one or more operating modes: obtaining, for at least one component in the respective subset of components, a respective target thermal energy transfer between the component and the respective subset of thermal transfer fluids in the thermal circuit in the operating mode; obtaining an aggregated thermal energy transfer availability for the respective subset of components, the aggregated thermal energy transfer availability indicative of a thermal energy that the respective subset of components is collectively able to exchange with the respective subset of thermal transfer fluids in the thermal circuit in the operating mode; and determining, based on the aggregated thermal energy transfer availability, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the thermal circuit in the operating mode.

10. The method of claim 9 , further comprising : determining whether all target thermal energy transfers of the thermal management system are achievable in each respective operating mode, based on the determination, for each of the one or more thermal circuits defined by the operating mode, whether the target thermal energy transfers of each of the at least one component in the respective subset of components are achievable in the operating mode; and providing one or more outputs indicating the result of the determining whether all target thermal energy transfers of the thermal management system are achievable in each respective operating mode; and determining, for operating modes in which the respective target thermal energy transfers are determined to be achievable, respective energy costs associated with the operating modes.11 . The method of claim 10, wherein when it is determined that target thermal energy transfers of the at least one component in the respective set of components are not achievable in the operating mode the method further comprises: outputting a circuit error margin, the circuit error margin indicating a difference between the target thermal energy transfer and a thermal energy transfer that is achievable; and determining for each thermal circuit of the operating mode an overall error margin by combining the circuit error margins for each of the thermal circuits of the operating mode.

12. The method of any previous claim, wherein the method further comprises selecting an operating mode based on the determinations.

13. A control system for controlling a thermal management system of an electric vehicle, the control system comprising one or more processors collectively configured to carry out the method of any one of claims 1 to 12.

14. Computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 1 to 12.

15. A vehicle comprising: the control system, of claim 13; and a thermal management system communicatively coupled to the control system.

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