Apparatus and method for vehicle range determination

Abstract

A control system (100, fig. 2) for estimating the range of a vehicle (10), a vehicle, and a method for estimating the range of a vehicle. The control system comprises one or more processors collectively configured to: following a first connection of a trailer to the vehicle, receive (302, fig. 3) a user input signal (310) indicative of a user selection of a trailer category from a plurality of predetermined trailer categories 702a-f; retrieve a seed value for the selected trailer category, the seed value indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category (304); determine an estimated remaining range of the vehicle with the connected trailer in dependence on the retrieved seed value (306); and output a range signal (330) indicative of the estimated remaining range of the vehicle with the connected trailer (308).

Description

TECHNICAL FIELD The present disclosure relates to an apparatus and methods for vehicle range estimation. Aspects of the invention relate to a control system for estimating the range of a vehicle, to a vehicle, and to a method for estimating a range of a vehicle. BACKGROUND It is known to provide an estimated remaining range of a vehicle, for example an estimated remaining distance which a vehicle is able to travel before refuelling (e.g. before recharging a battery power source of an electric or hybrid vehicle). Further, connecting additional elements to a vehicle, such as a trailer, can act to reduce the estimated remaining range of the vehicle because it takes more energy to move the vehicle when it is also pulling a trailer, so the distance the vehicle is able to travel before requiring refuelling or recharging is lower than if the vehicle was not towing a trailer. It can be challenging to provide an accurate estimate of remaining range because the value of the remaining range may depend on the specific parameters of the trailer, such as the size, weight, and aerodynamics. Particularly if the vehicle has not driven with the trailer previously, the remaining range can be challenging to estimate. 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 for estimating the range of a vehicle, to a vehicle, and to a method for estimating a range of a vehicle, as claimed in the appended claims. Disclosed herein is a control system for estimating the range of a vehicle, the control system comprising one or more processors collectively configured to: receive a user input signal indicative of a trailer category of a trailer connected to the vehicle; determine an estimated remaining range of the vehicle with the connected trailer in dependence on a retrieved seed value, the seed value indicative of an energy consumption of trailers of the trailer category; and output a range signal indicative of the estimated remaining range of the vehicle with the connected trailer. Advantageously, a user can select a trailer category of a connected trailer and the control system can indicate an estimated remaining range for that trailer type. The user can provide a simple input without any expert knowledge of the properties of the trailer nor does the vehicle need to have driven with the trailer attached fora reasonably accurate estimate of remaining range to be provided. The seed value provides the reasonable estimated remaining range of the vehicle, providing an advantageous trade-off of accuracy of estimated range provision and ease of non-expert user input in specifying the nature of the connected trailer. According to an aspect of the present invention there is provided a control system for estimating the range of a vehicle, the control system comprising one or more processors collectively configured to: following a first connection of a trailer to the vehicle, receive a user input signal indicative of a user selection of a trailer category from a plurality of predetermined trailer categories; retrieve a seed value for the selected trailer category, the seed value indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category; determine an estimated remaining range of the vehicle with the connected trailer in dependence on the retrieved seed value; and output a range signal indicative of the estimated remaining range of the vehicle with the connected trailer. Advantageously, a user can simply select a trailer category to indicate properties of a trailer which is being connected for the first time to the vehicle, ratherthan needing to know and then enter particular parameters of the trailer such as weight, wheelbase, number of axles, etc. The retrieved seed value can then provide for a reasonable estimated remaining range of the vehicle to be presented according to the type of trailer connected, providing an advantageous trade-off of accuracy of estimated range provision and ease of non-expert user input in specifying the nature of the connected trailer. The seed value may be based on prior tests and data obtained from possibly many other vehicles and trailers. This allows for the user to benefit from reduced range estimation data determined from previous vehicles and trailers, simply by selecting an appropriate trailer category for the connected trailer. This does not require any specialist knowledge of driving with that trailer, nor any complicated or extensive user input to specify details of the trailer connected. The control system may comprise one or more controllers collectively comprising at least one electronic processor having an electrical input for receiving an input signal; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to: following a first connection of a trailer to the vehicle, receive a user input signal indicative of a user selection of a trailer category from a plurality of predetermined trailer categories; retrieve a seed value for the selected trailer category, the seed value indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category; determine an estimated remaining range of the vehicle with the connected trailer in dependence on the retrieved seed value; and output a range signal indicative of the estimated remaining range of the vehicle with the connected trailer. The control system may be configured to determine the estimated remaining range of the vehicle by reducing an estimated remaining range of the vehicle without a connected trailer by a range reduction factor, the range reduction factor determined in dependence on the seed value. The seed value advantageously allows for a reasonable estimated remaining range to be presented to the user dependent on the trailer type connected, which can provide a more accurate estimation than simply providing a fixed percentage range reduction regardless of the trailer type for example. The seed value may be determined from previously determined values for that trailer type, so advantageously the estimated range presented may be determined from prior recorded real-world data. The control system may be configured to: receive a connection signal indicative of the first connection of the trailerto the vehicle; determine the trailer is connected to the vehicle in dependence on the received connection signal; and in dependence on the determination, output a control signal to a user interface of the vehicle to prompt the user to select a trailer category from the plurality of predetermined trailer categories. Advantageously, the option to select a trailer category can be automatically presented to the user when the trailer is determined to have been connected, thereby further simplifying any user interaction in relation to specifying the trailer connection and obtain the reduced range estimation. The control signal may be transmitted to an output device and cause the output device to output the plurality of predetermined trailer categories for user selection in some examples. Advantageously the user may be provided with an easy to use visual prompt to select a trailer category so the remaining range can be estimated. The control system may be configured to: receive a driving characteristic signal indicative of one or more driving characteristics of the vehicle with the connected trailer; determine an updated estimated remaining range of the vehicle with the connected trailer in dependence on the driving characteristic signal; and output an updated range signal indicative of the updated estimated remaining range of the vehicle with the connected trailer. Advantageously the vehicle can provide an initial reasonable estimated reduced range on connection of the trailer, and then when the vehicle is being driven with that trailer connected, the control system can adapt the provided estimated range according to how the vehicle and trailer are being driven for improved accuracy. The control system may be configured to: determine an updated seed value of the trailer in dependence on the driving characteristic signal; store the updated seed value of the trailer; following a subsequent connection of the trailer to the vehicle, receive a user input signal indicative of a user selection of the trailer category from the plurality of predetermined trailer categories; retrieve the updated seed value for the selected trailer category; determine an estimated remaining range of the vehicle with connected trailer in dependence on the retrieved updated seed value; and output a range signal indicative of the estimated remaining range of the vehicle with the connected trailer. Advantageously, following first connection of the trailer to the vehicle and the vehicle being driven with the trailer, the initial seed value may be determined to be different to that originally retrieved according to how the particular vehicle with the particular connected trailer has actually driven. The control system can therefore advantageously update the seed value and store this, such that a subsequent connection of the trailer to the vehicle allows for an estimated reduced range to be provided to the user in accordance with previous driving of the vehicle with that trailer, which provides improved accuracy through learnt driving and range estimation. The one or more driving characteristics may comprise one or more of: a terrain on which the vehicle is driving; weather conditions while the vehicle is being driven; a driving style with which the vehicle is being driven; and an operation status of one or more auxiliary vehicle functions while the vehicle is being driven. Such factors may affect the actual range remaining the vehicle and can be taken into account to improve remaining range estimation and update the seed value for the trailer category. In this way subsequent use of a trailer in that category allows for a more accurate estimated reduced range to be presented to the user because it is personalised to how the vehicle and trailer have been previously driven. A driving style may include consideration of, for example, gentle or aggressive braking, gentle or aggressive acceleration, and / or gear usage at various speed and accelerations of the vehicle. An operation status of one or more auxiliary vehicle functions may comprise, for example, climate control functions, and infotainment functions. The control system may be configured to: receive a disconnection signal indicative of disconnection of the trailer from the vehicle; determine an estimated remaining range of the vehicle without a connected trailer in dependence on the disconnection input signal; and output a range signal indicative of the estimated remaining range of the vehicle without a connected trailer. Advantageously, once the trailer is disconnected, the system can revert back to providing an estimated range from before the trailer was connected to the vehicle. Therefore, the system may have adapted the provided estimated range from the initial retrieval of the seed value following the vehicle being driven, but on removal of the trailer, the system need not gradually re-adapt back to providing an estimated range with no trailer connected, and can simply revert back to the last provided estimated range before the trailer was connected. The estimated remaining range of the vehicle without a connected trailer may be dependent on historical sole-vehicle range data, i.e. historical data of the range of the vehicle being driver without a trailer attached. The control system may further comprise one or more of: a display apparatus configured to display indications of each of the plurality of predetermined trailer categories; and a user input apparatus configured to receive the user selection of a trailer category from the displayed indications of each of the plurality of predetermined trailer categories. Advantageously, a driver may be presented with a visual indication of the available trailer categories from which to select a category appropriate to the trailer which has been connected via the user input apparatus, providing a simple and intuitive user interface from which to obtain an accurate estimated reduced range following collection of the trailer to the vehicle. The display apparatus and user input apparatus may both be comprised in a touch sensitive display of the vehicle, and the touch sensitive display may be configured to: display the indications of each of the plurality of predetermined trailer categories; and receive the user selection of a trailer category by detection of a user touch on the indication corresponding to the selected predetermined trailer category. Advantageously, the user input system may thus be intuitive, simple, and quick to use and allow for accurate range estimation to be presented to the user without any specialist knowledge of the trailer nor extensive user inputs to specify trailer parameters. The user input apparatus may be configured to receive a single user touch input as the user selection of a trailer category from the displayed indications of each of the plurality of predetermined trailer categories. Advantageously the user may provide one touch input to a simple list of trailer categories and be provided with the accurate estimated range of the vehicle with the trailer connected. The control system may comprise a local seed value storage means, and the control system may be configured to retrieve the seed value for the selected trailer category from the local seed value storage means. In other examples, the seed value may be retrieved from cloud storage / server off-vehicle etc. Advantageously, through use of a list of seed values (i.e. a relatively small amount of data) determined from previously collected data from other various vehicles and trailers, the seed values may be stored locally to the vehicle and therefore communication connection outside of the vehicle is not necessary for the range estimation to be provided to the user, for example if the vehicle is located somewhere out of wireless data communication range. Any updating of the seed values, through third-party updates or through personalisation following the users driving may be performed when the vehicle is back in data communication range. According to an aspect of the invention, there is provided a vehicle comprising any control system disclosed herein. Advantageously, the vehicle can be connected to a trailer for the first time and the user can specify a trailer category to obtain an estimated range independence on the connected trailer. According to an aspect of the invention, there is provided a method for estimating a range of a vehicle, the method comprising: receiving a user input signal indicative of a user selection of a trailer category from a plurality of predetermined trailer categories following a first connection of a trailer to the vehicle; retrieving a seed value for the selected trailer category, the seed value indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category; determining an estimated remaining range of the vehicle with connected trailer in dependence on the retrieved seed value; and outputting a range signal indicative of the estimated remaining range of the vehicle with connected trailer. A user can therefore simply select a trailer category to indicate properties of the trailer which is being connected for the first time to the vehicle, rather than needing to know and then enter particular parameters of the trailer such as weight, wheelbase, number of axles, etcetera. The retrieved seed value can then provide for an reasonable estimated remaining range of the vehicle to be presented according to the type of trailer connected, providing an advantageous trade-off of accuracy of estimated range provision and ease of non-expert user input in specifying the nature of the connected trailer. The method may comprise: receiving a connection signal indicative of the first connection of the trailer to the vehicle; determining the trailer is connected to the vehicle in dependence on the received connection signal; and outputting, in dependence on the determination, a control signal to a user interface of the vehicle to prompt the user to select a trailer category from the plurality of predetermined trailer categories. Advantageously, the user can be automatically presented with a selection of a trailer categories to choose from when the trailer is determined to have been connected, thereby further simplifying any user interaction in relation to specifying the trailer connection and obtain the reduced range estimation. The method may comprise: receiving a disconnection signal indicative of disconnection of the trailer from the vehicle; determining an estimated remaining range of the vehicle without a connected trailer in dependence on the disconnection input signal; and outputting a range signal indicative of the estimated remaining range of the vehicle without a connected trailer. Advantageously, once the trailer is disconnected, the system can revert back to providing an estimated range from before the trailer was connected to the vehicle. According to an aspect of the invention, there are provided a computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform any method disclosed herein. The computer readable instructions may be stored on a (e.g. non transitory) computer readable medium. 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 anyway 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 vehicle in accordance with an embodiment of the invention; Figure 2 shows a control system comprising a processor in accordance with an embodiment of the invention; Figure 3 shows a flow diagram of a process which a control system is configured to perform in accordance with an embodiment of the invention; Figure 4 shows a flow diagram of a process which a control system is configured to perform in accordance with an embodiment of the invention; and Figure 5 shows a flow diagram of a process which a control system is configured to perform in accordance with an embodiment of the invention; and Figure 6 shows a flow diagram of a process which a control system is configured to perform in accordance with an embodiment of the invention; and Figure 7 shows an example display apparatus operating in accordance with an embodiment of the invention; Figures 8a and 8b show schematically an adjusted relationship of energy consumption versus vehicle speed which may be used in range estimation in accordance with an embodiment of the invention; and Figure 9 shows an overall flow diagram of operation of a control system in a vehicle in accordance with an embodiment of the invention. DETAILED DESCRIPTION It is known to provide an estimated remaining range of a vehicle. For example an estimated remaining distance which a vehicle is able to travel before refuelling (e.g. before recharging a battery power source of the vehicle) may be provided to the driver of the vehicle. Towing a trailer can have a significant impact on vehicle range, and thus on the predicted range of a vehicle (including electric vehicles), due to the added mass of the trailer and the impact on aerodynamic drag to increase drag. It can be challenging to provide an accurate estimate of remaining range because this value may depend on the specific parameters of the trailer, such as the size, weight, and aerodynamicity, particularly if the vehicle 10 has not driven with the trailer previously. Embodiments disclosed herein can provide improvements in range prediction based on the type of trailer connected to a towing vehicle, and in some examples on the learned energy consumption when towing that type of trailer. The vehicle 10 of Figure 1 comprises a control system 100 as illustrated in Figure 2 which can provide range prediction for the vehicle 10 according to embodiments disclosed herein. A control system 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 2, and the control system 100 is for estimating the range of a vehicle 10. The control system 100 may be installed in the vehicle 10. The control system 100 comprises one or more controllers 110. The details of the control system 100 operation is explained in further detail with reference to Figures 3 to 6 and Figure 9. The control system 100 is configured to receive a user input signal 165 indicative of a user selection of a trailer category from a plurality of predetermined trailer categories following a first connection of a trailerto the vehicle 10. For example the user input signal 165 may be received from user selection of a trailer category presented for selection from a touch screen 160 or other input selection means. The touch screen 160 (e.g. a human machine interface, HMI) may present multiple trailer profiles, such as a general trailer, boat trailer, horse box, caravan, goods trailer, flatbed trailer, car trailer, etc, and the driver can select an option which matches the newly attached trailer. The control system 100 is configured to retrieve a seed value for the selected trailer category. The seed value is indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category. For example, from historical energy consumption values determined from other vehicles and trailers of a particulartrailer category (e.g. horse boxtrailer), a seed value indicative of an average energy consumption for horse boxes may be obtained and stored for retrieval. The control system 100 is configured to determine an estimated remaining range of the vehicle 10 with the connected trailer in dependence on the retrieved seed value. The remaining range may be determined, for example, based on one or more parameters of the vehicle (e.g., on the state of charge, SoC, of a traction battery of an electric vehicle, on a planned route as provided to a navigation system, on the weather conditions at the time of driving, on a determined tyre pressure of the vehicle tyres, or other parameter(s) apparent to the skilled person) and on the seed value. The control system 100 is then configured to output a range signal 155 indicative of the estimated remaining range of the vehicle with the connected trailer, for example to a display means 170 in the vehicle to indicate to the driver the estimated remaining range of the vehicle 10 with trailer. The control system 100 as illustrated in Figure 1 comprises one controller 110, although it will be appreciated that this is merely illustrative. The controller 110 comprises processing means 120 and memory means 130. The processing means 120 may be one or more electronic processing device 120 which operably executes computer-readable instructions. The memory means 130 may be one or more memory device 130. The memory means 130 is electrically coupled to the processing means 120. The memory means 130 is configured to store instructions, and the processing means 120 is configured to access the memory means 130 and execute the instructions stored thereon. The controller 110 comprises an input means 140 and an output means 150. The input means 140 may comprise an electrical input 140 of the controller 110. The output means 150 may comprise an electrical output 150 of the controller 110. The input 140 is arranged to receive a user input signal 165, for example from a user selection input device 160. The user input signal 165 is an electrical signal which is indicative of a user selection of a trailer category from a plurality of predetermined trailer categories following a first connection of a trailer to the vehicle 10, The output 150 is arranged to output a range signal 155 is indicative of the estimated remaining range of the vehicle with the connected trailer, which may be provided to an output means 170 such as display screen in the vehicle 10. A user can therefore, on first connecting a trailer to the vehicle 10, be presented with a series of predetermined trailer categories and select one category appropriate for the connected trailer. The selected trailer category is associated with properties of trailers of that category including the seed value. The seed value may be based on prior tests and data obtained from possibly many other vehicles and trailers, allowing for the userto benefit from reduced range estimation data as determined from previous vehicles and trailers. Thus, rather than the user needing to know, and then enter, particular parameters of the trailer such as weight, wheelbase, number of axles, etc., the retrieved seed value can provide for a reasonable estimated remaining range of the vehicle plus trailer. The estimated remaining range for the vehicle plus trailer can then be presented to the user. The control system provides an advantageous trade-off of accuracy of estimated range provision and ease of nonexpert user input. The control system 100 may be configured to determine the estimated remaining range of the vehicle by reducing an estimated remaining range of the vehicle without a connected trailer by a range reduction factor. The range reduction factor is determined in dependence on the seed value. For example, the range reduction may comprise a multiplier of the estimated range of the vehicle without trailer, e.g. 0.8x range, 0.67x range, or other value. The multiplier may depend on the range of the vehicle without trailer, for example 0.8x range if more than 100 miles range remain, 0.7x if less than 100 miles remain. For example, the range reduction may comprise a constant to be subtracted from the estimated range of the vehicle without trailer, e.g. range minus 50 kilometres, range minus 80 kilometres, or other value. The subtraction factor may depend on the range of the vehicle without trailer, for example range minus 50 kilometres if more than 100 miles range remain, range minus 80 kilometres less than 100 kilometres remain. The subtraction factor in some examples may be a proportion of the remaining range, e.g. the remaining range with trailer = remaining range without trailer minus 0.2x remaining range without trailer. The range reduction may be a combination of one or more multiplier, one or more subtraction factors, and / or another adjustment factor. The seed value advantageously allows for a reasonable estimated remaining range to be presented to the user dependent on the trailer type connected, which can provide a more accurate estimation than simply providing a fixed percentage range reduction regardless of the trailer type for example. The seed value may be determined from previously determined values for that trailer type, so advantageously the estimated range presented may be determined from prior recorded real-world data. Figure 3 illustrates a flow diagram of the method 300 described above performed by the control system 100. That is, the method 300 for estimating a range of a vehicle comprises, in step 302, receiving a user input signal 310 indicative of a user selection of a trailer category from a plurality of predetermined trailer categories following a first connection of a trailer to the vehicle. In step 304, the method comprises retrieving a seed value for the selected trailer category, for example from a seed value storage 320. The seed value is indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category. The method 300 comprises, in step 306, determining an estimated remaining range of the vehicle with connected trailer in dependence on the retrieved seed value; and in step 308, outputting a range signal 330 indicative of the estimated remaining range of the vehicle with connected trailer. Figures 4 to 6 and Figure 9 also illustrate methods, as flow diagrams, which may be performed by the control system 100. Figure 4 illustrates a method 400 which may be performed by the control system 100. In this example the control system 100 is configured to present options for the user to select a trailer category when the trailer is determined to have been connected. This may further simplify user interaction used to specifying the type of trailer connected and obtain the reduced range estimation. The control system 100 may be configured to receive a connection signal 410 indicative of the first connection of the trailer to the vehicle in step 402; determine the trailer is connected to the vehicle in dependence on the received connection signal in step 404; and in dependence on the determination, output a control signal 420 to a user interface of the vehicle to prompt the user to select a trailer category from the plurality of predetermined trailer categories in step 406. The control signal 420 may be transmitted to an output device 170, such as a display screen in the vehicle, and cause the output device to output the plurality of predetermined trailer categories for user selection in some examples. Step 402 of Figure 4 may be performed before the steps of Figure 3; that is, a connection signal to indicate a trailer has been connected may be received 402 before the user makes an input to select the trailer category of connected trailer 302. In an example, if no user input signal 310 is received following trailer connection, then a solo vehicle consumption (energy consumption parameter) used to estimate remaining range for the vehicle without trailer is “protected” (not changed). In such a case, whereby a trailer is detected to have been connected but no user selection of trailer type is made, an “unknown” trailer category may be selected forthat trailer and energy consumption characteristics forthat unknown trailer type may be recorded as a seed value for trailers of the “unknown” trailer type, and stored e.g. in the seed value storage 320. Figure 5 illustrates a method 500 which may be performed by the control system 100. The control system 100 may provide an initial reasonable estimated reduced range on connection of the trailer as discussed above by use of the seed value. Later, when the vehicle is being driven with that trailer connected, the control system 100 can adapt the provided estimated range according to how the vehicle and trailer are being driven, for improved accuracy. In some examples, the control system 100 may run an algorithm which starts with the seed value for each type of trailer, and can then learn the real world consumption for each type of trailer for improved accuracy. The control system 100 may be configured to: receive a driving characteristic signal 510 indicative of one or more driving characteristics of the vehicle with the connected trailer in step 502. The one or more driving characteristics may comprise one or more of: a terrain on which the vehicle is driving; weather conditions while the vehicle is being driven; a driving style with which the vehicle is being driven; and an operation status of one or more auxiliary vehicle functions while the vehicle is being driven. A driving style may include consideration of, for example, gentle or aggressive braking, gentle or aggressive acceleration, or steering characteristics (e.g. gentle or sudden) of the vehicle. An operation status of one or more auxiliary vehicle functions may comprise, for example, climate control functions, and infotainment functions. Such factors may affect the actual range remaining the vehicle 10 and can be taken into account to improve remaining range estimation and update the seed value for the trailer category. The control system 100 may then be configured to determine an updated estimated remaining range of the vehicle with the connected trailer in dependence on the driving characteristic signal in step 504. The control system 100 may then output an updated range signal 520 indicative of the updated estimated remaining range of the vehicle with the connected trailer in step 506. The control system 100 may therefore be able to tune the initial range prediction based on the seed value according to how the vehicle 10 is actually being driven and provide improved accuracy of range estimation. This may be thought of as learning an energy consumption of the vehicle to provide improved accuracy of range estimation. In some examples, the control system 100 may be configured to determine an updated seed value of the trailer in dependence on the driving characteristic signal in step 508, and store the updated seed value of the trailer 510, for example in a seed value storage means 530. In this way, following first connection of the trailer to the vehicle and the vehicle being driven with the trailer, the initial seed value may be determined to be different to that originally retrieved according to how the particular vehicle with the particular connected trailer has actually driven. Following a subsequent connection of the trailer to the vehicle, the control system 100 may be configured to receive a user input signal 540 indicative of a user selection of the trailer category from the plurality of predetermined trailer categories in step 512, and retrieve the updated seed value for the selected trailer category in step 514. The control system 100 may be configured to determine an estimated remaining range of the vehicle with connected trailer 516 in dependence on the retrieved updated seed value, and output a range signal 550 indicative of the estimated remaining range of the vehicle with the connected trailer in step 518. The control system can therefore advantageously use the updated stored seed value so when there is a subsequent connection of the trailer to the vehicle, the control system can provide an improved estimated reduced range to the user in accordance with the trailer category and the characteristics of the vehicle 10 driving with that particular trailer, which provides improved accuracy through the learnt effects of driving with the trailer. In other words, actual historical energy consumption values can be used for future range prediction. In some examples, the historical energy consumption values may be used when a driver is setting a destination in a navigation system. For example, if a driver is entering a route to an on-board navigation system and that route (or route with similar characteristics) has previously been driven with the trailer, then the control system 100 can provide an updated seed value taking into account the previous driving along the same or similar route, to more accurately provide an estimated range. The consumption curve from a previous journey may be communicated back from the control system 100 to a navigation system, so that the navigation system can plan a route accounting for the previous energy consumption data for the vehicle (e.g. to identify charging points en route) and route energy information may be provided back from the navigation system to the control system 100 so that the estimated remaining range for the planned route may be output. Thus, examples disclosed herein allow for improved range estimation fora vehicle with a newly-attached trailer through the use of the seed value for that trailer category (type). Subsequent driving of the vehicle with the trailer can be used to update the seed value according to real driving data for further refinement of the seed value for the particular trailer, vehicle, and driver combination, and therefore improved accuracy of range estimation. The control system may also manage the disconnection of the trailer to provide an estimated remaining range as discussed in relation to Figure 6. Figure 6 illustrates a method 600 which may be performed by the control system 100. The control system 100 may be able to revert back to providing an estimated range from before the trailer was connected to the vehicle. In step 602 the control system 100 is configured to receive a disconnection signal 610 indicative of disconnection of the trailer from the vehicle 602. In step 604, the control system 100 is configured to determine an estimated remaining range of the vehicle without a connected trailer in dependence on the disconnection input signal 604. In step 606 the control system 100 is configured to output a range signal 620 indicative of the estimated remaining range of the vehicle without a connected trailer. Therefore, on removal of the trailer, the control system 100 need not re-adapt back to providing an estimated range with no trailer connected. Instead the control system 100 can simply revert back to the last provided estimated range before the trailer was connected. The estimated remaining range of the vehicle without a connected trailer may be dependent on historical sole-vehicle range data, i.e. historical data of the range of the vehicle being driver without a trailer attached in some examples. Any of the methods discussed here, such as those described above in relation to Figure 3 to 6, may be performed by computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method(s). The computer readable instructions may be stored on a (e.g. non transitory) computer readable medium, such as the memory means 130 shown in Figure 2. Figure 7 illustrated an example HMI displayed on a display apparatus 700 in a vehicle 10. The display apparatus 700 is configured to present trailer categories 702a-fto a user, for example on connection of a trailer to the vehicle 10. The display apparatus 700 may be a display output screen or touch sensitive screen, for example. The display apparatus 700 is configured to display indications 702a-f of each of the plurality of predetermined trailer categories. The control system 100 may thus comprise a user input apparatus 700 (e.g. the illustrated display apparatus) which is configured to receive the user selection of a trailer category from the displayed indications of each of the plurality of predetermined trailer categories. The user input apparatus may comprise the display apparatus 700 (e.g. as a touch sensitive layer of the display apparatus 700) in some examples, as shown. The user input apparatus may, in some examples, comprise one or more soft keys (not shown) displayed on a touch sensitive display screen or touch panel, or one or more hard keys (not shown). The keys may be interacted with to allow for selection of a displayed trailer categories 702a-f. Thus, a driver can be presented with a visual indication 702a-f of the available trailer categories from which to select a category appropriate to the trailer which has been connected. The user interface can be simple and intuitive and, by virtue of the stored seed values corresponding to the displayed visual indications 702a-f, still provide an accurate estimated reduced range of the vehicle plus trailer. In examples where the display apparatus and user input apparatus are both comprised in a touch sensitive display 700 of the vehicle 10, the touch sensitive display 700 may be configured to both display the indications of each of the plurality of predetermined trailer categories 702a-f; and receive the user selection of a trailer category 702a-f by detection of a user touch on the indication 702a-f corresponding to the selected predetermined trailer category. In this way the user input system can be intuitive, simple, and quick to use and does not require any extensive user inputs, menu navigation, or knowledge of the particular trailer specifications, to specify relevant trailer parameters for range estimation. The user input apparatus 700 in some examples may be configured to receive a single user touch input as the user selection of a trailer category from the displayed indications 702a-f of each of the plurality of predetermined trailer categories. Advantageously the user may simply provide one touch input to a simple list of trailer categories and be provided with the accurate estimated range of the vehicle with the trailer connected. The control system 100 in some examples may comprise a local seed value storage means (e.g. storage means 320 or 530), and the control system 100 may be configured to retrieve the seed value for the selected trailer category from the local seed value storage means 320, 530. Advantageously, through use of a list of seed values (i.e. a relatively small amount of data) determined from previously collected data from other various vehicles and trailers, the seed values may be stored locally to the vehicle 10 and therefore communication connection outside of the vehicle 10 is not necessary for the range estimation to be provided to the user, for example if the vehicle is located somewhere out of wireless data communication range such as an underground car park. Any updating of the seed values, through third-party updates or through personalisation following the user’s driving, may be performed when the vehicle is back in data communication range. In other examples, the seed value may be retrieved from cloud storage or a server (not shown) located off-vehicle by means such as a wireless receiver or transceiver (not shown) which may be compatible with a wireless transmission protocol such as Wi-Fi ® or 4G / 5G. In yet further examples, the seed value may be retrieved from cloud storage or a server located off-vehicle and stored on the local seed value storage means 320, 530. In this way, the stored seed value can be periodically updated when the vehicle is in data communication range with the cloud storage or the server, and then subsequently retrieved from the local storage means 320, 530 when the vehicle is out of range. A user can therefore simply select a trailer category to indicate properties ofthe trailer which is being connected for the first time to the vehicle, rather than needing to know and then enter particular parameters ofthe trailer such as weight, wheelbase, number of axles, etc. The retrieved seed value can then provide for an reasonable estimated remaining range of the vehicle to be presented according to the type of trailer connected, providing an advantageous trade-off of accuracy of estimated range provision and ease of non-expert user input in specifying the nature of the connected trailer. Figures 8a and 8b show schematic relationships of energy consumption versus vehicle speed which illustrates how range estimation may be adapted in accordance with an embodiment of the invention. The consumption curves may be constructed, for example, using seed consumption values at a plurality of speed breakpoints (e.g. at seven breakpoints), and the consumption curves may then learn / adapt and be adjusted for each trailer category. These adjusted seed values may be transmitted to a navigation system for route planning. Figure 8a shows a plot of energy consumption 804 (in this example measured in kilowatt hours per kilometre, kWh / km) plotted against vehicle speed 802 (in this example measured in kilometres per hour, kph. It can be seen that the relationship curve 806 shows energy consumption 804 increases with vehicle speed 802 in a non-linear relationship with an increased rate of energy consumption 804 as vehicle speed 802 increases. An offset to the energy consumption curve 806 may be determined as illustrated and shown in Figure 8b. At point 808 in Figure 8a, a towing difference from the energy consumption curve 806 of the vehicle without a trailer and an actual energy consumption of the vehicle pulling the trailer from the point 808 is determined. At point 810 a non-towing difference from the energy consumption curve 806 of the vehicle without a trailer and an actual energy consumption of the vehicle without the trailer from point 810 is determined. The difference between the towing difference from point 808 and the non-towing difference from point 810 may be determined to be an offset 814, which is shown in Figure 8b where the energy consumption curve 806 of Figure 8a is adjusted by the offset 814 to provide an offset energy consumption curve 812 which more accurately reflects the energy consumption of the vehicle when towing the trailer. Another example of determining an amended energy consumption curve as an alternative to that of Figure 8b is to learn an entirely new curve for each trailer type profile. Figure 9 shows an overall flow diagram of operation of a control system in a vehicle in accordance with an embodiment of the invention. It will be appreciated that not all the steps in Figure 9 are essential and that the steps illustrates relate to plural features which may be combined as shown; in this example, the steps cover connection of a trailer to a vehicle for the first time, detection of the trailer connection, input of the trailer type, handling trailer types which do not affect the range estimation as well as trailers which do after range estimation, and feedback from driving the vehicle with the trailer to update the seed value for that trailer type. Step 902 represents connection of the trailer (or trailer equipment) to the vehicle. Connection may comprise mechanical connection of the trailer to a towbar of the vehicle. Connection may comprise electrical connection connecting electrical apparatus of the trailer to the vehicle so the electrical apparatus can be powered by the vehicle. A trailer may be, for example, a flatbed trailer, a caravan, a horse box, or a boat trailer. Trailer equipment may be considered to be, for example, an item which connects to the trailer connection but not does “trail” on the driving surface, such as a bike rack or lightboard which is affixed to the rear of the car and which connects to the electncal trailer connection so that lights on the bike rack or hghtboard can be illuminated when the vehicle lights are illuminated (e.g. side lights, brake lights, fog light). Step 904 represents detection of the trailer or trailer equipment by the control system 100 or other detection means of the vehicle 10. For example, making an electrical connection of the trailer to a vehicle towbar electrical connector may be detected by electrical circuitry. Another example of detecting trailer connection may be visual detection by image capture means identifying the presence ofthe trailer at the rear of the vehicle. Another example of detecting trailer connection may be physical detection by mechanical sensing which can sense the trailer physically connected to the towbar or towing means ofthe vehicle. This step 904 may be considered to comprise receipt of a connection signal indicative of the first connection of the trailer to the vehicle. Step 906 represents provision of an indicator to the driver of the vehicle that the trailer or trailer equipment has been connected to the vehicle. The driver may be asked to confirm that the trailer has been connected. The indicator may be provided to an in-vehicle output device such as a HMI or infotainment type screen. In other examples the indicator may be provided to a portable electronic device ofthe drivers, such as a smartphone or smart watch. This step may be considered to comprise determining that the trailer is connected to the vehicle in dependence on the received connection signal. Decision step 908 represents receiving confirmation or otherwise from the driver that the trailer is connected. If the driver responds no, shown as “N” in the Figure, then the method moves onto step 932 which represents output ofthe estimated range remaining ofthe vehicle without trailer connection; this may be based on the estimated range provided at the end ofthe previous drive cycle and / or any planned route according to a route set in a navigation system. If the driver responds yes, shown as “Y” in Figure 9, then the method moves onto step 910 whereby the driver is presented with trailer category options for selection of a trailer category matching the trailer ortrailer equipment detected as attached to the vehicle. This step may be considered to comprise outputting a control signal to a user interface ofthe vehicle to prompt the user to select a trailer category from the plurality of predetermined trailer categories in dependence on the determination that the trailer is connected to the vehicle. In this example, step 912 represents determination ofthe trailertype being a type which causes an adjustment ofthe remaining range estimation based on a seed value forthat trailer type, or a trailer equipment type which does not cause an adjustment ofthe remaining range estimation (in the same way that no adjustment to the remaining range is determined if the driver confirms in step 908 that no trailer is connected). If the trailer type is a trailer equipment type which does not cause any adjustment ofthe remaining range, such as a cycle rack or lightboard, then the method moves to step 932 which represents output ofthe estimated range remaining ofthe vehicle without trailer connection. In such a case, the solo vehicle range (i.e. without trailer) may be “protected”, i.e., not updated as the vehicle plus trailer equipment is driven, so that when the trailer equipment is disconnected, the solo range prediction behaviour from before trailer equipment connection is maintained. If the trailer type is a type which does warrant an adjustment ofthe remaining range estimation based on a seed value forthat trailer type the method moves to step 914. Step 914 represents retrieving a seed value for the selected trailer category selected in step 910. The seed value is indicative of an average energy consumption of a plurality of trailers associated with the selected trailer. Step 916 represents determining an estimated remaining range of the vehicle with the connected trailer in dependence on the retrieved seed value. Step 918 represents outputting a range signal indicative of the estimated remaining range of the vehicle with the connected trailer. Step 920 indicates that an indication or notification is output to the driver according to the output range signal. For example, the range signal may be output to a display means in the vehicle or a portable electronic device of the driver, to indicate the estimated remaining range of the vehicle including the trailer. Once the initial range estimation is provided, in step 922, the driver begins driving with the connected trailer. In Step 924 the control system 100 causes the remaining range output to be updated as the remaining range of the vehicle decreases through power source use as the vehicle is being driven (e.g. the energy stored in a traction battery of the vehicle is depleted due to powering the vehicle). Step 926 represents the step of updating the seed value for the trailer according to the vehicle driving with the trailer connected. This may be considered to be updating or adapting the range prediction of the vehicle plus trailer according to learned energy consumption. Step 926 may be thought of in some examples as comprising receipt of a driving characteristic signal indicative of one or more driving characteristics of the vehicle with the connected trailer; determination of an updated estimated remaining range of the vehicle with the connected trailer in dependence on the driving characteristic signal; and outputting of an updated range signal indicative of the updated estimated remaining range of the vehicle with the connected trailer (which can feed into the range signal which is output in step 918). That is, the result of step 926 may be a determined updated seed value which is fed back to step 918 to update the estimated remaining range provided to the driver. In examples similar to this, in which the trailer is not being connected for the first time, and the trailer has previously been connected to the vehicle and the vehicle has driven with the trailer attached, then step 920 may represent the user selection of a previously configured trailer profile, and the subsequent range prediction value will be based on the previously learnt consumption forthat trailer category and presented in step 924 once the driver begins driving in step 922. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A control system for estimating the range of a vehicle, the control system comprising one or more processors collectively configured to:following a first connection of a trailer to the vehicle, receive a user input signal indicative of a user selection of a trailer category from a plurality of predetermined trailer categories;retrieve a seed value for the selected trailer category, the seed value indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category;determine an estimated remaining range of the vehicle with the connected trailer in dependence on the retrieved seed value; andoutput a range signal indicative of the estimated remaining range of the vehicle with the connected trailer.

2. The control system of claim 1, configured to determine the estimated remaining range of the vehicle by:reducing an estimated remaining range of the vehicle without a connected trailer by a range reduction factor, the range reduction factor determined in dependence on the seed value.

3. The control system of any preceding claim, configured to:receive a connection signal indicative of the first connection of the trailer to the vehicle;determine the trailer is connected to the vehicle in dependence on the received connection signal; andin dependence on the determination, output a control signal to a user interface of the vehicle to prompt the user to select a trailer category from the plurality of predetermined trailer categories.

4. The control system of any preceding claim, configured to:receive a driving characteristic signal indicative of one or more driving characteristics of the vehicle with the connected trailer;determine an updated estimated remaining range of the vehicle with the connected trailer in dependence on the driving characteristic signal; andoutput an updated range signal indicative of the updated estimated remaining range of the vehicle with the connected trailer.

5. The control system of claim 4, configured to:determine an updated seed value of the trailer in dependence on the driving characteristic signal;store the updated seed value of the trailer;following a subsequent connection of the trailer to the vehicle, receive a user input signal indicative of a user selection of the trailer category from the plurality of predetermined trailer categories;retrieve the updated seed value for the selected trailer category;determine an estimated remaining range of the vehicle with connected trailer in dependence on the retrieved updated seed value; andoutput a range signal indicative of the estimated remaining range of the vehicle with the connected trailer.

6. The control system of claim 4 or claim 5, wherein the one or more driving characteristics comprise one or more of:a terrain on which the vehicle is driving;weather conditions while the vehicle is being driven;a driving style with which the vehicle is being driven; andan operation status of one or more auxiliary vehicle functions while the vehicle is being driven.

7. The control system of any preceding claim, configured to:receive a disconnection signal indicative of disconnection of the trailer from the vehicle;determine an estimated remaining range of the vehicle without a connected trailer in dependence on the disconnection input signal; andoutput a range signal indicative of the estimated remaining range of the vehicle without a connected trailer.

8. The control system of any preceding claim, further comprising:a display apparatus configured to display indications of each of the plurality of predetermined trailer categories; anda user input apparatus configured to receive the user selection of a trailer category from the displayed indications of each of the plurality of predetermined trailer categories.

9. The control system of any preceding claim, comprising a local seed value storage means), wherein the control system is configured to retrieve the seed value for the selected trailer category from the local seed value storage means.

10. A vehicle comprising the control system of any of claims 1 to 9.

11. A method for estimating a range of a vehicle, the method comprising:receiving a user input signal indicative of a user selection of a trailer category from a plurality of predetermined trailer categories following a first connection of a trailer to the vehicle;retrieving a seed value for the selected trailer category, the seed value indicative of an average energy consumption of a plurality of trailers associated with the selected trailer category;determining an estimated remaining range of the vehicle with connected trailer in dependence on the retrieved seed value; andoutputting a range signal indicative of the estimated remaining range of the vehicle with connected trailer.

12. The method of claim 11, comprising:receiving a connection signal indicative of the first connection of the trailer to the vehicle;determining the trailer is connected to the vehicle in dependence on the received connection signal; andoutputting, in dependence on the determination, a control signal to a user interface of the vehicle to prompt the user to select a trailer category from the plurality of predetermined trailer categories.

513. The method of claim 14 or claim 15, comprising:receiving a disconnection signal indicative of disconnection of the trailer from the vehicle;determining an estimated remaining range of the vehicle without a connected trailer in dependence on the disconnection input signal; and10 outputting a range signal indicative of the estimated remaining range of the vehicle without aconnected trailer.

14. Computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method of any of claims 11 to 13.19

Images