Thermal management

Abstract

A control system (208) for controlling a thermal management system (350) of a hybrid electric vehicle (10) is described. The control system (208) comprises one or more controller and is configured to

Description

TECHNICAL FIELD The present disclosure relates to a system and method for thermal management of a hybrid electric vehicle. Aspects of the invention relate to a system, a method of controlling a thermal management system, a computer program and a vehicle. BACKGROUND Hybrid Electric Vehicles (HEVs) are propelled both by an internal combustion engine (ICE) and an electric motor powered by electrical power stored in batteries. These vehicles may be operated in a variety of modes, including a ICE only mode in which the vehicle is propelled entirely by the internal combustion engine (and during which the vehicle batteries may be recharged, for example using the engine, or regenerative braking), an electric-only mode in which the vehicle is propelled entirely by the electric motor(s), and in which the ICE may be switched off, and optionally a dual-propulsion mode in which the powertrain is driven by both the ICE and the electric motors in parallel. To maximise efficiency, it is desirable to operate certain vehicle components, such as the battery, at a particular temperature. Both passive (no electrical cost) and active (electrical cost) heating and / or cooling can be used to do this. To minimise emissions, and (assuming electric charging occurs at low cost) to minimise journey cost, it is desirable to operate the vehicle in an electric-only mode for as much of a journey as possible. This may particularly be the case for portions of the journey in which the vehicle is travelling through a low emission or no emission zone. Additionally, in some cases a too hot or too cold battery may trigger an engine restart (that is, switching to propulsion using the internal combustion engine) so that the driver demand gets fulfilled. It will be appreciated that this is particularly undesirable in a low emission zone. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a control system, a method, a computer program and a vehicle, as claimed in the appended claims. In one aspect, there is provided a control system according to claim 1. Also disclosed herein is a control system for controlling a thermal management system of a hybrid electric vehicle, the control system comprising one or more controller, the control system configured to: receive route information relating to an identified route which may be undertaken by the vehicle; determine, in dependence on the route information, that the vehicle is expected to enter a predetermined geographical area; and output a command to the thermal management system to actively heat or cool one or more components of the vehicle in advance of the vehicle entering the geographical area, in dependence on the determination. In this way, an electric vehicle drive zone (geographical area in which electric operation of the hybrid vehicle is to be prioritised compared with other portions of a journey) using geofencing (to identify the area) and journey profile technology (to identify when the vehicle will enter and traverse the area), and to actively thermally precondition the powertrain (or components thereof) to arrive at optimal temperature when entering the electric vehicle drive zone which leads to enhanced range while in the drive zone (thus ensuring, or at least increasing the likelihood that, the vehicle can remain in the electric only mode throughout the entirety of the traversal of the area. The one or more components are preferably to be heated or cooled to a predetermined temperature which represents an overheating or undercooling of a current optimal temperature requirement for the one or more components. In other words, a different heating and / or cooling regime may be applied for each of (a) the journey until a determined point in advance of entry into the geographical area, (b) the portion of the journey from the determined point until entry into the geographical area, (c) during the traversal of the geographical area, and (d) after exit from the geographical area. In particular, for (a) a heating and / or cooling regime seeks to optimise the powertrain efficiency instantaneously and / or for the journey as a whole. This may involve maintaining the powertrain component temperature as closely as possible to the optimal operating temperature for the component. For (b), instantaneous powertrain efficiency may be disregarded, or be secondary to preparing the powertrain component temperature to be optimal for entry into the geographical area. For (c), the powertrain efficiency during the traversal of the geographical area is prioritised, and it may for example be permissible to allow powertrain components to deviate from a desired temperature to avoid the need to expend electrical energy actively heating or cooling the components. As a result, the powertrain efficiency may be suboptimal at exit from the geographical area. For (d), the thermal management system is required to recover from the deviation referred to above, but generally to return to the same operating procedures as for (a). The heating or cooling may be scheduled so that the one or more components reach the predetermined temperature at the time or location at which the vehicle is due to enter the geographical area. In this way the heating or cooling starts only when it needs to - so that the temperature is as desired when the low emission zone is reached. The schedule comprises a time or distance in advance of the point of entry into the geographical area at which the heating or cooling starts. This minimises, as far as possible, the energy requirements of active heating and / or cooling. The geographical area may be an area within which vehicle transit using an internal combustion engine is penalised or prohibited, for example a low-emission or zero-emission zone. The control system may be configured to determine a heating or cooling schedule for the one or more components in dependence on the route information in relation to a portion of the route leading up to entry into the geographical area. The control system may be configured to estimate, using the route information, a heat load and / or cooling load for the one or more components for the portion of the journey leading up to entry of the vehicle into the geographical area based on the route information, and to determine the heating or cooling schedule based on the estimated heat load. In particular, this portion of the route may have characteristics (such as estimated speed or gradient) which will give rise to a particular power load profile, and thus temperature profile for the components (the temperature of the components generally increasing with increasing power load). This makes it possible to identify a temperature gap between the estimated component temperature and the desired (entry to geographical area) component temperature on the approach to the area. Since the rate of cooling or heating is known (predetermined characteristic of the active heating or cooling system), an activation time forthose heating / cooling systems may be identified in order that the vehicle component reaches the desired temperature at or just in advance of entry into the geographical area. The control system is configured to determine a degree of confidence that the vehicle will enter the predetermined geographical area, and to output the control signal to carry out the active heating or cooling only if the determined degree of confidence satisfies a threshold. The degree of confidence may be dependent on one or more of whether the driver has manually entered the route, the route having been automatically selected and the driver having actively confirmed the route, and the vehicle following the route for at least a predetermined distance or percentage thereof. This is beneficial, since it is undesirable to overheat or undercool the powertrain components unless such a geographical area is going to be traversed. This technique should only be used if there is a high degree of confidence of entering the low emission zone. This is because there is an energy cost associated with the heating / cooling which should be avoided unless it is very likely to pay off by permitting increased range in the low emission zone. The control system may be configured to control the thermal management system to actively heat or cool the one or more components such that the portion of the journey during which the one or more components are actively heated or cooled is from a predetermined distance or a predetermined time before the entry into the predetermined geographical area. A duration or distance for the active heating or cooling may be dependent on one or more environmental parameters (such as ambient temperature or solar load), and / or one or more road parameters of the journey (such as road gradient and estimated vehicle speed for each segment of the journey), and / or on one or more operating parameters of the vehicle (such as a vehicle mode and whether an air conditioning system is active). The operating parameters of the vehicle may comprise a power demand for the portion of the journey during which the one or more components are to be actively heated or cooled. The power demand may, in effect, cover any vehicle / driver specific parameter which might influence how much power is being demanded of the vehicle electrical system, for example speed, acceleration, whether or not the air conditioning system is active etc. The control system may be configured to automatically switch the vehicle to an electric only mode when the vehicle enters the geographical area. According to another aspect, there is provided a system comprising the control system as described above and the thermal management system. According to another aspect, there is provided a vehicle comprising the system or the control system described above. According to another aspect, there is provided a method according to claim 14. Also disclosed herein is a method for controlling a thermal management system of a hybrid electric vehicle, the method comprising: receiving route information relating to an identified route which may be undertaken by the vehicle; determining, in dependence on the route information, that the vehicle is expected to enter a predetermined geographical area; and outputting, in dependence on the determination, a command to the thermal management system to actively heat or cool one or more components of the vehicle in advance of the vehicle entering the geographical area. According to another aspect, there is provided computer readable instructions which, when executed by a computer, are arranged to perform a method according to the above. The one or more components which are actively heated or cooled may comprise a battery, and / or one or more inverters, and / or an oil supply. The thermal control system may comprise one or more of a pump and a fan and an electric heater. 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. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic representation of a vehicle having a battery, an electric propulsion system, a control system, and a display; Figures 2A and 2B schematically illustrate a control system and a group of vehicle controllers; Figure 3 schematically illustrates various controllers, components and volumes of the vehicle involved with thermal management; and Figure 4 is a schematic flow diagram illustrating the various steps of a thermal management method. DETAILED DESCRIPTION FIG. 1 illustrates an example of a vehicle 10 in which embodiments of the invention can be implemented. In some, but not necessarily all examples, the vehicle is a passenger vehicle, also referred to as a passenger car or as an automobile. In other examples, embodiments of the invention can be implemented for other applications, such as commercial vehicles. The vehicle 10 comprises a plurality of systems including an internal combustion engine (ICE) 104, electric propulsion system 12, control system 208, and energy storage means 22 for powering the electric propulsion system 12, such as one or more batteries, for example one or more high voltage batteries. The combustion engine 104 may be a reciprocating piston internal combustion engine. The vehicle 10 is a hybrid vehicle because the vehicle 10 also comprises the traction battery 22 and at least one electric traction motor 12. The traction battery 22 is an electrical energy source for the electric traction motor 12. In some examples, the electric traction motor 12 is a motor-generator, while in other examples a separate generator is provided. In some examples, the electric traction motor 12 is a starter-generator, operable to perform the function of a starter motor. The purpose of the generator is to recharge the traction battery 22, for example by implementing a regenerative braking function. The control system 208 is configured to implement any one or more of the methods described herein. FIG. 2A illustrates how the control system 208 may be implemented. The control system 208 of FIG. 2A illustrates a controller 200. In other examples, the control system 208 may comprise a plurality of controllers 200 onboard and / or off board the vehicle 10. In examples any suitable control system 208 can be used. The controller 200 of FIG. 2A includes at least one processor 202; and at least one memory device 204 electrically coupled to the electronic processor 202 and having instructions 206 (for example a computer program) stored therein, the at least one memory device 204 and the instructions 206 configured to, with the at least one processor 202, cause any one or more of the methods described herein to be performed. FIG. 2A therefore illustrates a control system 208, wherein the one or more electronic controllers 200 collectively comprise: at least one electronic processor 202 having an electrical input for receiving information associated with energy storage control; and at least one electronic memory device 204 electrically coupled to the at least one electronic processor 202 and having instructions 206 stored therein; and wherein the at least one electronic processor 202 is configured to access the at least one memory device 204 and execute the instructions thereon so as to cause the control system 208 to perform and / or cause performance of any one or more of the methods described herein. Also illustrated in the example of FIG. 2A are one or more vehicle systems 226. In examples, the vehicle system(s) 226 can comprise any suitable vehicle system(s). For example, the vehicle system(s) 226 can comprise any suitable vehicle system(s) 226 from which the control system 208 can receive and / or to which the control system 208 can transmit, directly or indirectly, one or more signals 20, for example to control an energy storage means 22 of a vehicle 10. In examples, the one or more vehicle systems 226 comprise one or more systems involved in control of an energy storage means of the vehicle 10. In examples, the one or more vehicle systems 226 comprise one or more systems involved in control of state of charge of an energy storage means 22 of the vehicle 10. For example, one or more vehicle systems 226 can comprise any suitable system or systems 226 of the vehicle configured to provide energy to and / or draw energy from energy storage means 22 of the vehicle 10. For example, the one or more vehicle systems 226 can comprise one or more energy recovery systems and / or one or more electric motors and so on. In examples, the one or more vehicle systems 226 can comprise one or more systems configured to report on the present state and / or present usage of energy by the energy storage means 22 of the vehicle 10. In examples, the one or more vehicle systems 226 can comprise one or more systems configured to provide information to allow a determination of a predicted destination 12 for the vehicle 10 and / or an associated confidence value. In examples, the one or more systems 226 comprise a powertrain controller module and / or an infotainment system and / or a HVAC controller. FIG. 2B illustrates a non-transitory computer readable storage medium 218 comprising the instructions 206 (computer software). Accordingly, FIG. 2B illustrates a non-transitory computer readable medium 218 comprising computer readable instructions 206 that, when executed by a processor 202, cause performance of at least the method of one or more of FIG. 4 and / or as described herein. The present invention is concerned with electric powertrain efficiency. In particular, certain components of the electric powertrain, such as batteries, inverters and electric motors, operate most effectively or efficiently at a specified temperature, or within a specified temperature range. If the temperature deviates from these, efficiency may drop. In addition to physical components, the oil used to lubricate the transmission and e-motor can be also cooled / heated. It will be appreciated that the oil may in this case be considered as a vehicle component. Increasing the temperature of the oil results in lower friction forces hence higher efficiency. This then leads to an increase in vehicle range. As a result of the temperature dependence of powertrain efficiency, it is known to passively and actively heat or cool vehicle components to the specified temperatures. Where active heating or cooling is used, this consumes electrical power, and therefore itself negatively impacts on efficiency. It will be generally appreciated that it is only worth heating or cooling powertrain components if the energy efficiency savings made outweigh the energy cost of heating or cooling. The present technique recognises that for certain portions of the journey, maximising electric powertrain efficiency, and thus maximising vehicle range in an electric-only mode, may be more important than maximising efficiency for the journey overall (or for other parts of the journey). A key example is a low emission or no emission zone, such as is frequently in place in major cities to reduce pollution from heavy traffic. It is highly desirable that electric powertrain efficiency be maximised while the vehicle is travelling in such an area. As will be described below, this may involve preconditioning (pre-heating or pre-cooling) vehicle components prior to entering the low emission zone such as to reduce the requirement for actively heating or cooling those components while the vehicle is in the low emission zone. Maximising efficiency within the low emission zone includes seeking to enter the low emission zone with a component (e.g. battery) temperature which is optimal, as well as preferably avoiding the use of active heating or cooling while in the low emission zone (since this uses battery power and thus reduces In order to achieve this, knowledge of route information (including expected vehicle speed and road gradient over the journey) is used to optimise total electrical energy usage for components within the entire cooling circuit, and to ensure the battery reaches optimal operating temperature range across all operating conditions, while minimising energy expenditure. With the present technique, prior to entering a Low Emission Zone (LEZ), a heat load for the battery is estimated based on the route ahead, and within the cooling and refrigerant circuit, electrical consumptions are calculated for components to bring battery temperature into its optimal range at the point of entry into the low emission zone. A predictive thermal management model represents the cooling and refrigerant circuit for the vehicle, the circuit including battery, heater, coolant pumps, cooling fans and electrical compressors. This model is able to predict a battery temperature in dependence on the characteristics of the thermal management model and battery power data determined based on the route ahead (using eHorizon). Based on the computations, a predictive thermal request may be made which requests one of the following heating / cooling modes: 00: Inactive (allow the original function to operate as normal) 01: No action (a request to perform no battery heating or cooling) 02: Active battery cooling (request active battery cooling by using the refrigerant system) 03: Passive battery cooling (request passive battery cooling using the low temperature radiator) 04: Active battery heating (request active battery heating using the electrical heater) The present technique uses eHorizon segment data (described subsequently) to calculate segment battery power profile. That is, an expected battery power requirement applicable during each segment of the journey ahead is determined. Battery transient behaviour is emulated to represent real world driving scenarios. The predictive thermal model then assesses the electrical consumptions for components and predicts the battery temperature profile and thermal mode request for the journey ahead based on those electrical consumptions. In parallel, it also calculates the distance to (the point of entry into) the LEZ when the thermal control (pre-warming I pre-cooling) starts. In Figure 3, several of the vehicle systems 226 are shown, including a user Plug-ln-Vehicle Infotainment system (PIVI) 310, a controller 320 and a powertrain control module 350. The PIVI 310 carries out navigation functionality, and outputs eHorizon data to the controller 320. The PIVI 310 also comprises a user interface via which the user may input commands. The eHorizon data comprises route information concerning a journey planned to be undertaken by the vehicle. The powertrain control module 350 carries out various control functions in relation to the vehicle electric powertrain (as is conventional), and in the present technique controls the temperature of a vehicle battery 360, electric motors 370 and inverters 380. In particular, the powertrain control module 350 passively and / or actively heats and / or cools the battery 360, motors 370 and inverters 380 in order that the powertrain is operated as efficiently as possible. Various heating and / or cooling systems may be used to heat or cool the various components, including an and a pump and a fan to cool the battery, motors and inverters. The eHorizon data output by the PI VI 310 comprises, for each of the segments of the planned journey, a segment offset (Oseg), a segment gradient (Sseg), and a segment speed (Vseg). The segment offset is in effect a length / distance of the segment (since subtracting the offset of a preceding segment from a particular segment will provide the length of the particular segment), the segment gradient is a road gradient for the segment. This may be an average gradient for the portion of the road corresponding to that segment. Since segments need not be all of the same length, generally new segments will be defined whenever the road gradient changes significantly, with the result that the gradient is at least generally uniform for the portion of road corresponding to any given segment. The segment speed is an assumed average speed for the segment, based on historical traffic data from multiple users. It will be appreciated that different users may traverse the segment at different speeds, and the segment speed is an average of these. The gradient and expected vehicle speed for any given gradient may be used to estimate an expected power load on the vehicle during that segment. For example, the greater the positive gradient, the greater the expected power load, and the greater the speed, the greater the expected power load. With the present invention, the expected power load is useful for determining the expected battery (or other component) temperature (heat load) at each segment of the journey, and in particular at the point of entry into a low emission zone. Based on this temperature and a known optimal temperature for the battery (or other component), a length or duration of a preconditioning zone, in advance of the low emission zone, during which active heating or cooling of the powertrain components is to be carried out, can be determined. More particularly, the difference between the expected temperature at the point of entry into the low emission zone and the optimum temperature for operating the battery (or an optimum starting temperature of the battery when entering the low emission zone) may be used along with a heating or cooling rate for the thermal management system to determine how long it will take to heat or cool the battery to the desired temperature. This time or distance in advance of the low emission zone represents a heating or cooling schedule. It will thus be appreciated that the control system is able to estimate, using the route information (segments, including expected vehicle speed and gradient), a heat load for the one or more components for the portion of the journey leading up to entry of the vehicle into the geographical area based on the route information, and to determine the heating or cooling schedule based on the estimated heat load. It will be appreciated that the same principles apply not just to the battery, but also to other vehicle components being preconditioned in this way. For each component being actively heated or cooled in accordance with the present technique, there will be a time calculated, resulting in separate time values. In other words, the time in advance of the low emission zone at which active heating or cooling will be applied may be different for each component of the electric powertrain being preconditioned in this way. More generally, a duration or distance for the preconditioning zone may be dependent on one or more environmental parameters and / or on one or more route parameters and / or on one or more operating parameters of the vehicle. The environmental factors may include the ambient temperature, the route parameters may be the gradient and likely speed (and if available, traffic information) in the sequence of segments leading up to the low emission zone, and the vehicle operating parameters may be a terrain mode of the vehicle, and an indication of a power load of vehicle systems such as lights, HVAC etc. The operating parameters of the vehicle may comprise a power demand for a final portion of the route. A journey may be considered to be a route between a starting location and a destination, optionally via one or more waypoints. In one example, the route is published by the vehicle navigation system (part of the PI VI 310). In this example, the starting location, destination and waypoints may be deterministic because they are specified by user inputs to the vehicle navigation system. Therefore, in this example, the route is deterministic. In another example, the route is predicted from machine learning. The machine learning could indicate where the vehicle 10 has previously been driven and at which times. This enables the route to be determined probabilistically. For example, at 8am on a weekday the driver normally drives to work, which trains a predictive algorithm to determine that when the driver enters their vehicle 10 at 8am on a weekday, they are going to follow a particular route. With the present technique, it is not desirable to actively heat or cool the vehicle components beyond the need to generally optimise electric powertrain efficiency for the journey as a whole or for current driving parameters if the vehicle is in fact not going to pass through the low emission zone (at the time and / or position expected). Accordingly, it is desirable that the present technique should be applied only if a degree of confidence in the planned route is sufficient. In practice, the degree of confidence should be high of the vehicle entering and traversing the low emission zone. This is because if the vehicle does not enter and traverse this zone, the powertrain efficiency (battery / inverter) may be operated less efficiently for the journey as a whole, for no reason. In some implementations, the degree of confidence in a planned route may be determined by a combination of factors. These factors include a type of destination - which may be one of a destination set by the driver in the navigation system, a destination identified as a commute route and acknowledge by driver, a destination identified as commute route but not acknowledged by driver, and no destination selected or identified. In the case of a destination set by or acknowledged by the driver, the confidence requirement may be considered to have been met. In the case of an identified but unacknowledged commute route, additional consideration is required. This consideration may be made in dependence on a base confidence in the commute route as a percentage value, for example an 89 % confidence level, a number of reroutes from the commute route, and a (remaining) distance to the destination in km. For example, in this case the overheating / undercooling in advance of entry into the low emission zone may be carried out only if the confidence in the commute route is greater than a threshold value (for example 80%), if the vehicle has been driven on the route for at least a predetermined proportion (for example 10%) of the identified commute without re-routing (driver deviation and another route identified), this check being done using the distance to destination signal in km, and if there have been no more than a specified maximum number (for example 3) of re-routes from the initial identified commute route. If any of these conditions are not met, the present technique is not utilised and the powertrain is not prepared for optimal operation in the low emission zone. Once the route is known, and satisfies the confidence requirements, the power use of the vehicle 10 is predicted for the journey following that route. The present technique uses vehicle speed, but may additionally use other useful variables including a distance-dependent parameter such as distance, and a gradient-dependent parameter such as road gradient or elevation points from which gradient can be determined. Other useful parameters include vehicle mass, aerodynamic drag coefficient(s), road curvature (e.g. curve radius-dependent or a number of bends), road type (e.g. road classification, number of lanes). The controller 320 may be configured to perform a force analysis of the available parameters to predict the power to be used for (each portion or segment of) the vehicle journey, in accordance with Newton’s second laws of motion. In some examples, a model of the drivetrain and / or powertrain of the vehicle 10, and auxiliary electrical loads (e.g. lighting, heating, cooling, engine accessories) can be used to account for losses therefrom. The journey may be represented as a plurality of segments. The speed, gradient and other information is quantized by the controller 320 to a constant value over each segment. The number of segments into which the journey is divided corresponds to a degree of spatial and / or temporal resolution. The width of each segment may correspond to a particular time and / or distance (width on the x-axis), and may be different from the width of at least one other segment. In an example, each segment represents a line between two nodes on a graph representative of a road network. The graph may be that used by a route-finding algorithm such as Dijkstra’s algorithm implemented in the vehicle navigation system, for finding the route. The node-to-node spacing is variable because each node may correspond to one of a real road junction or to a helper node for improving spatial resolution (e.g. accounting for road curves). Therefore the segment widths are variable. The segmentation may occur in the vehicle navigation system for the purposes of route calculation, prior to receipt of the information, or in other examples the controller 320 may perform the segmentation. The information provided to the powertrain control module, to estimate the energy usage or power demand of the various segments of the journey, may be considered to be a driving profile for the journey. The driving profile therefore comprises an expected vehicle speed for each of a plurality of segments of the journey (each segment having a particular gradient, and a length). Using the driving profile, and in particular these three parameters, along with a set of constants C1, C2, C3, it is possible to estimate an amount of power which will be likely to be consumed during traversal of each segment, according to the following Equation (1): e [041 . , , .-r *? L 4 / j. J-*! ^3 ' $ seamen? «« J Psegment(W) = (1) In equation (1), Psegment [W] is the amount of power (in Watts) consumed by traversal of the segment (output), Vsegment is the segment speed, m is the mass of the vehicle (kg), g is the gravitational constant, Ssegment is the gradient of the segment. With the present technique, the power load for the segments leading up to entry to the low emission zone can be used to determine an expected battery temperature at the point of entry into the low emission zone (assuming no active heating or cooling), and thus the amount of additional heating or cooling required to attain the desired battery temperature at point of entry into the low emission zone. Based on a heating / cooling capability of the thermal management system (that is, how quickly can the battery be heated or cooled), an amount of time (in advance of entry into the low emission zone) required to achieve the desired temperature can be determined. In conventional thermal management, the efficiency of the electric powertrain for the whole journey ahead is optimised. This involves a combination of no heating or cooling, active heating, active cooling and passive cooling, with a view to ensuring that the battery temperature is as close as possible to an optimum operating temperature, but only applying active cooling where the efficiency benefits achieved by doing so outweigh the energy cost of heating or cooling the battery. In predictive thermal management taking into account the presence of a low emission zone, components are heated or cooled to a predetermined temperature which represents an overheating or undercooling of a current optimal temperature requirement for those components, or of a temperature determined for overall journey optimisation. In some cases this involves actively pre-heating or pre-cooling the components in advance of entering the low emission zone. In other cases this involves not actively heating or cooling the components while travelling within the low emission zone, or relaxing thermal regulation requirements (while in the low emission zone) to permit greater deviation from optimum temperatures / ranges than permitted for other portions of the journey. Active heating and / or cooling may then be more aggressively applied after the vehicle has exited the low emission zone, to bring component temperatures back to optimal levels for the remainder of the journey. For example, in hot ambient conditions, pre-cooling of the vehicle battery prior to entering the low emission zone is beneficial for highest efficiency (and greatest range) within the low emission zone. In cold ambient conditions, pre-warming of the vehicle battery prior to entering the low emission zone is beneficial for highest efficiency (and greatest range) within the low emission zone. In both cases, a higher battery temperature may be permissible while in the low emission zone. That is, active battery cooling may be suppressed while in the low emission zone, subject to safety constraints, provided that this leads to increased range in an electric only mode of the vehicle. Referring to Figure 4, a flow diagram for the method is provided. At a step S1, route information is received from the PIVI. This route information will be in relation to a journey to a destination. In some implementations the step S1 may also comprise determining whether a degree of confidence in the destination can be satisfied. If not, the process simply terminates. At a S2, it is determined whether or not the journey enters and / or passes through a low emission zone. If not, then at a step S3 the process terminates. If the journey is determined to enter or pass through a low emission zone, then at a step S4 the battery temperature profile is calculated for the journey ahead based on various parameters. These parameters may include the mass of the vehicle, the frontal area of the vehicle, an aerodynamic drag coefficient, air density, route information (slope, speed and distance for each journey segment as described above), a road load coefficient, transmission gear ratio, driveline losses, inverter and battery losses, and a thermal constant for the battery. At a step S5 it is determined whether, at the point at which the vehicle enters the low emission zone, the battery temperature profile indicates that natural heating / cooling will result in the battery being at the optimal temperature to maximise the electric powertrain efficiency of the vehicle. If so, then at the step S6 it is determined that no preconditioning is required, and the process ends. If not, then at a step S7 a time required to precondition the vehicle (that is, an amount of time in advance of the time at which the vehicle is expected to enter the low emission zone) is determined. This amount of time may depend on a difference in temperature between the expected battery temperature at point of entry into the low emission zone and an optimal temperature for the battery. At a step S8, it is determined whether the preconditioning zone (portion of the journey in advance of the low emission zone by a duration equal to that determined at the step S7) has been reached. Once it has been reached, then at a step S9, preconditioning begins. It will be appreciated that the preconditioning comprises either actively heating or cooling the battery, depending on whether the expected battery temperature (at point of entry into the low emission zone) is greater than or less than the optimum temperature of the battery. If the expected battery temperature is less than the optimum battery temperature, active heating will be applied as preconditioning, whereas if the expected battery temperature is greater than the optimum battery temperature, active cooling will be applied as preconditioning. In some implementations, the control system may then automatically switch the vehicle to an electric only mode when the vehicle enters the geographical area. As used herein “for” should be considered to also include “configured or arranged to”. For example, “a control system for” should be considered to also include “a control system configured or arranged to”. For purposes of this disclosure, it is to be understood that reference to ‘the control system being configured to’ is to be understood to mean ‘the one or more controllers of the control system are collectively configured to’. The controller(s) described herein can each comprise a control unit or computational device having one or more electronic processors, the one or more processors collectively configured to perform the control system functionality set out in the control system claims. A vehicle and / or a system thereof may comprise a single control unit or electronic controller or alternatively different functions of the controller(s) may be embodied in, or hosted in, different control units or controllers. A set of instructions could be provided which, when executed, cause said controller(s) or control unit(s) to implement the control techniques described herein (including the described method(s)). The set of instructions may be embedded in one or more electronic processors, or alternatively, the set of instructions could be provided as software to be executed by one or more electronic processor(s). For example, a first controller may be implemented in software run on one or more electronic processors, and one or more other controllers may also be implemented in software run on one or more electronic processors, optionally the same one or more processors as the first controller. It will be appreciated, however, that other arrangements are also useful, and therefore, the present disclosure is not intended to be limited to any particular arrangement. In any event, the set of instructions described above may be embedded in a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors / computational device, including, without limitation: a magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; or electrical or other types of medium for storing such information / instructions. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application. The blocks illustrated in the FIG. 4 may represent steps in a method and / or sections of code in the computer program 206. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted. As used herein, the term “determining” (and grammatical variants thereof) can include, not least; calculating, computing, processing, deriving, investigating, looking up (for example, looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (for example, receiving information), accessing (for example, accessing data in a memory) and the like. Also “determining” can include resolving, selecting, choosing, establishing, and the like. Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. Features described in the preceding description may be used in combinations other than the combinations explicitly described. Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not. Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A control system for controlling a thermal management system of a hybrid electric vehicle, the control system comprising one or more controllers, the control system configured to:receive route information relating to an identified route which may be undertaken by the vehicle;determine, in dependence on the route information, that the vehicle is expected to enter a predetermined geographical area;determine a degree of confidence that the vehicle will enter the predetermined geographical area; andoutput a command to the thermal management system to actively heat or cool one or more components of the vehicle in advance of the vehicle entering the geographical area, in dependence on the determination that the vehicle is expected to enter the predetermined geographical area and only if the determined degree of confidence satisfies a threshold.

2. The control system of claim 1, wherein the one or more components are to be heated or cooled to a predetermined temperature which represents an overheating or undercooling of a current optimal temperature requirement for the one or more components.

3. The control system of claim 2, wherein the heating or cooling is scheduled so that the one or more components reach the predetermined temperature at the time or location at which the vehicle is due to enter the geographical area.

4. The control system of any preceding claim, wherein the geographical area is an area within which vehicle transit using an internal combustion engine is penalised or prohibited.

5. The control system according to any preceding claim, the control system being configured to determine a heating or cooling schedule for the one or more components in dependence on the route information in relation to a portion of the route leading up to entry into the geographical area.

6. The control system according to claim 5, the control system being configured to estimate, using the route information, a heat load and / or cooling load for the one or more components for the portion of the journey leading up to entry of the vehicle into thegeographical area based on the route information, and to determine the heating or cooling schedule based on the estimated heat load.

7. The control system according to any preceding claim, wherein the degree of confidence is dependent on one or more of whether the driver has manually entered the route, the route having been automatically selected and the driver having actively confirmed the route, and the vehicle following the route for at least a predetermined distance or percentage thereof.

8. The control system according to claim 5, the control system being configured to control the thermal management system to actively heat or cool the one or more components such that the portion of the journey during which the one or more components are actively heated or cooled is from a predetermined distance or a predetermined time before the entry into the predetermined geographical area.

9. The control system according to claim 8, wherein a duration or distance for the active heating or cooling is dependent on one or more environmental parameters, and / or one or more road parameters of the journey, and / or on one or more operating parameters of the vehicle.

10. The control system of claim 9, wherein the operating parameters of the vehicle comprise a power demand for the portion of the journey during which the one or more components are to be actively heated or cooled.

11. The control system of any preceding claim, the control system being configured to automatically switch the vehicle to an electric only mode when the vehicle enters the geographical area.

12. A system comprising the control system of any preceding claim and the thermal management system.

13. A vehicle comprising the system of claim 12 or the control system of claims 1 to 11.

14. A method for controlling a thermal management system of a hybrid electric vehicle,the method comprising:receiving route information relating to an identified route which may be undertaken by the vehicle;determining, in dependence on the route information, that the vehicle is expected to enter a predetermined geographical area;determining a degree of confidence that the vehicle will enter the predetermined geographical area; and5 outputting, in dependence on the determination that the vehicle is expected toenter the predetermined geographical area and only if the determined degree of confidence satisfies a threshold, a command to the thermal management system to actively heat or cool one or more components of the vehicle in advance of the vehicle entering the geographical area.1015. Computer readable instructions which, when executed by a computer, are arranged to perform a method according to claim 14.

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