GB2592886A

GB2592886A - Control of vehicle range calculation

Info

Publication number: GB2592886A
Application number: GB1917884.7A
Authority: GB
Inventors: Hancock Matthew; Boulter Stephen; Shin Minsuk
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2019-12-06
Filing date: 2019-12-06
Publication date: 2021-09-15
Anticipated expiration: 2039-12-06
Also published as: GB201917884D0; GB2592886B

Abstract

A method of calculating the range of a vehicle comprising an electric motor and a battery comprises determining a first range estimate in dependence on a previous distance travelled, determining a second range estimate based on a portion of the previous distance travelled, and selectively outputting the first or second estimate in dependence on distance travelled or travelable by the vehicle. The selective output may change from outputting the first to the second estimate in dependence on a threshold distance travelled by the vehicle on a journey. Also disclosed is a method of calculating range by receiving state of charge data for the battery, determining first and second calculated energy consumption using a respective first and second estimation method, determining a range estimate in dependence on the state of charge data and the first and second calculated energy consumption, and outputting the range estimate. The dependency on the first or second calculated energy consumption may be changed in dependence on the state of charge data and may be a continuous variation over a range of the state of charge of the battery. As the state of charge decreases, the dependency on the first/second estimate may respectively decrease/increase.

Description

CONTROL OF VEHICLE RANGE CALCULATION

TECHNICAL FIELD

The present disclosure relates to control of vehicle range calculation. In particular, but not exclusively it relates to control of vehicle range calculation for an electric vehicle (EV) or hybrid electric vehicle (HEV).

BACKGROUND

EVs and some HEVs are able to drive on all-electric power. The driver is presented with a calculated range estimate for all-electric driving. Range informs the driver of how far or how long they can drive until available energy has been depleted. The range depends on current energy content (e.g. state of charge) of an energy storage means (e.g. traction battery). The range also depends on the rate of energy consumption of the energy storage means, which depends on both the vehicle and the driver.

A future rate of energy consumption for range prediction may be based extrapolation (learning/memory) from a past rate of energy consumption.

If the driver only drives short journeys, temperature-related rate of energy consumption is high for at least the first 0 to 10 kilometres of a journey. Temperature-related losses include, for example, operating the energy storage means at an inefficient temperature until it reaches an optimum temperature, operating the torque source (e.g. electric traction motor) at an inefficient temperature until it reaches an optimum temperature, and operating HVAC (heating ventilation and air conditioning) to bring the vehicle cabin to a setpoint temperature. Temperature-related losses are not a dominant factor for long journeys.

A calculated range that learns from past driving may be low if the vehicle was recently only driven on short journeys, and high if the vehicle was recently driven on long journeys. The calculated range may not take into account that drivers of electric vehicles will often recharge between short journeys. Learning from recent short journeys could result in a range that underestimates the range capability of the vehicle if the vehicle is going to be driven on a long journey. The range capability is the ability to perform a single long journey to depletion.

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 system, and computer software as claimed in the appended claims.

According to an aspect of the invention there is provided a control system for controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and energy storage means, the control system comprising one or more controllers, wherein the control system is configured to: determine a first range estimate indicative of a first range travelable by the vehicle in dependence on a previous distance travelled by the vehicle; determine a second range estimate indicative of a second range travelable by the vehicle in dependence on a portion of the previous distance travelled; and selectively output the first range estimate or the second range estimate in dependence on distance travelled or travelable by the vehicle.

An advantage is enabling greater confidence in the range capabilities of the vehicle. This is because monitoring of the distance travelled or travelable by the vehicle on the journey informs automatic or semi-automatic control of which range estimation methods are used (whole previous distance or a portion of the previous distance), to compromise between accuracy and consistency.

The selective output may be configured to change from outputting the first range estimate to outputting the second range estimate in dependence on a threshold distance travelled or travelable by the vehicle on the journey. An advantage is increasing range estimate consistency in the early part of a journey to more consistently reflect the range capabilities of the vehicle, and increasing range estimate accuracy in the later part of a journey taking into account the actual recent conditions encountered (driving habits, temperatures, etc).

According to an aspect of the invention there is provided a control system for controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and energy storage means, the control system comprising one or more controllers, wherein the control system is configured to: receive state of charge data indicative of a state of charge of the energy storage means; determine a first calculated energy consumption of the vehicle using a first estimation method; determine a second calculated energy consumption of the vehicle using a second different estimation method; determine a range estimate indicative of a range travelable by the vehicle, in dependence on the first calculated energy consumption of the vehicle, the second calculated energy consumption of the vehicle, and the state of charge data; and output the range estimate.

An advantage is enabling greater confidence in the range capabilities of the vehicle. This is because monitoring of the state of charge informs automatic or semi-automatic control of which range estimation methods are used (e.g. whole previous distance or a portion of the previous distance), to compromise between accuracy and consistency.

The control system may be configured to control a change in the dependency of the range estimate on the first calculated energy consumption and on the second calculated energy consumption may in dependence on the state of charge data. As the state of charge of the energy storage means decreases, the dependency of the range estimate on the first calculated energy consumption may decrease, and the dependency of the range estimate on the second calculated energy consumption may increase. An advantage is increasing range estimate consistency when energy availability is high, and increasing range estimate accuracy when energy availability is low taking into account the actual recent conditions encountered (driving habits, temperatures, etc).

The change may be a continuous variation over a range of the state of charge of the energy storage means. An advantage is enabling greater confidence in the range capabilities of the vehicle by preventing sudden changes of the range estimate.

The first estimation method may be based on prior energy consumption over the previous distance travelled by the vehicle and the second estimation method may be based on prior energy consumption over a portion of the previous distance travelled by the vehicle.

The first estimation method may be based on an average prior energy consumption over the previous distance travelled by the vehicle, and the second estimation method may be based on an average prior energy consumption over the portion of the previous distance travelled by the vehicle.

The portion of the previous distance travelled may be less than half the total previous distance travelled by the vehicle indicated by the vehicle distance data. An advantage is significant control over stability and accuracy.

According to an aspect of the invention there is provided a system comprising the control system, and a human-machine interface for providing feedback to a user (e.g. driver) of the vehicle, wherein the human-machine interface is configured to receive the output from the control system. The human-machine interface may be configured to provide user feedback indicative of the range estimate based on the output from the control system.

According to an aspect of the invention there is provided a vehicle comprising the control system or the system.

According to an aspect of the invention there is provided a method of controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and an energy storage means, the method comprising: determining a first range estimate indicative of a first range travelable by the vehicle in dependence on a previous distance travelled by the vehicle; determining a second range estimate indicative of a second range travelable by the vehicle in dependence on a portion of the previous distance travelled; and selectively outputting the first range estimate or the second range estimate in dependence on distance travelled or travelable by the vehicle.

According to an aspect of the invention there is provided a method of controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and an energy storage means, the method comprising: receiving state of charge data indicative of a state of charge of the energy storage means; determining a first calculated energy consumption of the vehicle using a first estimation method; determining a second calculated energy consumption of the vehicle using a second different estimation method; determining a range estimate indicative of a range travelable by the vehicle, in dependence on the first calculated energy consumption of the vehicle, the second calculated energy consumption of the vehicle, and the state of charge data; and outputting the range estimate.

According to an aspect of the invention there is provided computer software that, when executed, is arranged to perform the method. According to another aspect of the present invention, there is provided a non-transitory computer-readable storage medium comprising the computer software.

In some examples, the one or more controllers collectively comprise: at least one electronic processor having an electrical input for receiving information; and at least one electronic 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 cause the control system to control the determining and the output.

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: Fig 1 illustrates an example of a vehicle; Fig 2A illustrates an example of a control system; Fig 2B illustrates an example of a computer-readable storage medium; Fig 3 illustrates a graph depicting an example of variation of vehicle energy consumption rate and journey frequency with respect to distance travelled; Fig 4 illustrates a graph depicting an example of actual and driver-extrapolated range, and predicted range with respect to distance travelled; Fig 5A illustrates an example of a method that transitions between range estimation methods; Fig 5B illustrates another example of a method that blends between range estimation methods; and Fig 6 illustrates a graph depicting an example of actual and driver-extrapolated range, and predicted range with respect to distance travelled.

DETAILED DESCRIPTION

Fig 1 illustrates an example of a road vehicle 1 (Vehicle' herein) in which embodiments of the invention can be implemented. In some, but not necessarily all examples, the vehicle 1 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.

The vehicle 1 may be an electric vehicle (EV) or a hybrid electric vehicle (HEV), comprising an electric torque source ('electric traction motor' herein). An EV lacks an internal combustion engine (ICE), while an HEV additionally comprises an ICE. Some HEVs such as plugin hybrid electric vehicles (PHEVs) may comprise an all-electric driving mode.

An EV or HEV as shown in Fig 1 comprises at least one energy storage means 14 for traction energy, such as a traction battery or supercapacitor. The EV/HEV also comprises at least one electric traction motor 10, and an electrical circuit 12 configured to transfer electrical energy between one or more traction batteries and one or more electric traction motors. Associated components such as inverters are omitted for clarity.

Fig 2A illustrates a control system 200. The control system 200 comprises one or more controllers. One controller 202 is shown, as an example.

The controller 202 of Fig 2A includes at least one electronic processor 204; and at least one electronic memory device 206 electrically coupled to the electronic processor 204 and having instructions 208 (e.g. a computer program) stored therein, the at least one electronic memory device 206 and the instructions 208 configured to, with the at least one electronic processor 204 cause any one or more of the methods described herein to be performed.

The functionality of the control system 200 may be centralized or distributed. The control system 200 may comprise on-board (in-vehicle) hardware and/or software. Additionally or alternatively, the control system 200 may comprise off-board hardware and/or software.

According to Fig 2A, output from the control system 200 causes a human-machine interface 214 (HMI) to provide feedback to a user of the vehicle 1. The control system 200 and the HMI 214 may together define a system, and may be supplied together or separately. The HMI 214 is configured to receive output from the control system 200, such as range estimates. The HMI 214 is configured to provide user feedback indicative of the range estimates based on the output from the control system 200, and in response to receiving the output from the control system 200.

The HMI 214 may be output-only (e.g. display/speaker), or may support user input and user output (e.g. touch-screen display). In some examples, the HMI 214 may be located within the vehicle 1. The HMI 214 may be located within a field of view of a desired seat of the vehicle 1 such as a driver's seat. Alternatively, the HMI 214 may be external to the vehicle 1, for example at a vehicle fleet tracking station.

According to Fig 2A, an energy monitor 212 within or associated with the control system 200 may provide data indicative of current energy consumption of the vehicle 1, such as a current rate of energy consumption of the vehicle 1. The current data may be calculated based on a simulated energy model of the vehicle 1. The current energy consumption data may be provided to the control system 200.

The control system 200/energy monitor 212 may calculate statistics related to the energy consumption of the vehicle based continual or periodic monitoring of the current energy consumption data. For example, an average prior energy consumption of the vehicle 1 may be updated based on the current energy consumption data. The period over which the energy consumption is averaged may vary. The average may be a rolling average to minimise data storage requirements, or an average determined by other means. An average is not the only usable statistic -for example a median or other parameter could be used instead.

For example, according to a first range estimation method (also referred to as an 'estimation method' herein), a first range estimate may be based on average prior energy consumption over a first previous distance travelled. In an implementation, the average prior energy consumption may be a rate of energy consumption. The rate may be expressed as rate per unit distance, for example. The estimation method may be configured to obtain remaining energy data such as state of charge data, and extrapolate the average prior energy consumption rate (e.g. per unit distance) to determine the number of units of distance (e.g. kilometres) travelable by the vehicle until the remaining energy reaches a defined depleted state.

According to a second range estimation method, a second range estimate may be based on average prior energy consumption over a second, different previous distance travelled. The second distance may be a portion of the first distance. The second estimation method may extrapolate the average prior energy consumption rate over the shorter distance. The shorter-distance average would be more volatile than the longer-distance average, and more responsive to a recent and current context (driving-related and/or temperature-related energy consumption).

It would be appreciated that the range estimates could also take into account energy consumption data relating to other vehicles and/or could be location-specific, to improve dataset size/relevance.

In various examples herein the control system 200 is configured to automatically or semiautomatically change the range estimation method on which the outputted range estimate is based, during a journey. Each range estimation method may represent an energy consumption averaged over a different previous distance travelled by the vehicle. The different previous distances may be predetermined or may be manually specified.

Once the range estimate to be output has been calculated/selected, the control system 200 outputs the range estimate of the calculated range to cause the HMI 214 to output (feed back) the range estimate to the user. The range may be an all-electric driving range, or an overall range if different. Causing the HMI 214 to output range estimates assists the driver in performing the task of driving the vehicle 1 by means of a continued and guided human-machine interaction process. For example, the range estimates guide the driver's control of the rate of energy consumption of the vehicle 1, such as their driving style, their accessory usage such as an HVAC temperature setpoint, their route/destination, etc. The dashed line in Fig 2A from the driver to the energy monitor 212 indicates a feedback loop. If continuous/periodic data recording is performed, the effect of the driver's response to the indicated rate of energy consumption may be captured as the averages are updated with new energy consumption data, causing a feedback loop which affects range calculations. The impact of the driver's response on the calculated range depends on the averaging distance used in the range calculation, and has a greater impact for smaller prior averaging distances.

Fig 2B illustrates a non-transitory computer-readable storage medium 216 comprising the instructions 208 (computer software).

Fig 3 illustrates a graph depicting an example of variation of vehicle energy consumption rate (right y-axis) with respect to distance travelled (x-axis) in a journey. The rate of energy consumption is high for the first few kilometres of a journey, due to temperature-related effects for EVs and HEVs. Short journeys therefore consume a greater rate of energy. The rate of energy consumption reduces for longer journeys, because temperatures are non-optimal for only a small proportion of the overall journey.

Fig 3 also indicates a typical frequency distribution (left y-axis) of journey distance travelled (x-axis) by a typical user of a vehicle 1. Most journeys are short, with only a few long journeys.

If the control system 200 can predict that a long journey is about to be performed, for example based on navigation information, then the range estimation method may be adapted automatically to give a true indication of range capabilities. However, aspects of this invention described below can adapt the range estimation methods based on a current state of the vehicle 1 without necessarily requiring predictions or knowledge of how long/far the vehicle 1 will be driven.

Fig 4 indicates various ranges (y-axis) compared with distance travelled (x-axis). In Fig 4, a solid straight line represents the actual range capability of the vehicle 1 if the vehicle 1 is to be driven long-distance to energy depletion. A dashed line represents the predicted (calculated) range estimate as indicated to the driver based on a single short-distance estimation method only. The chain-dashed line represents a driver-extrapolated range. The driver-extrapolated range is the range capability that the driver expects with when they start the journey. This may cause the driver to underestimate the vehicle's capability to perform a long journey.

The predicted range significantly underestimates the actual range capability for most of a long journey. The predicted range may start lower than the actual range capability as shown, due to past data indicating short, inefficient previous journeys. The predicted range may decrease steeply for the first few kilometres of a journey, for similar reasons. However, if the driver were to continue driving, the rate of decrease of the predicted range would gradually reduce until the predicted range starts to gradually converge with the actual range capability. The range prediction depicted in Fig 4 is therefore not useful for planning journeys of a different length from those indicated by the past data. What is needed is a control method that gives the driver greater confidence in the range capabilities of the vehicle 1.

Fig 5A illustrates an improved method 500 for controlling range calculation of a vehicle 1. The method is computer-implemented. The method 500 may be performed by the control system 200. The method 500 at least comprises: determining a first range estimate indicative of a first range travelable by the vehicle 1 in dependence on a previous distance travelled by the vehicle 1 (block 502); determining a second range estimate indicative of a second range travelable by the vehicle 1 in dependence on a portion of the previous distance travelled (block 504); and selectively outputting the first range estimate or the second range estimate in dependence on distance travelled or travelable by the vehicle 1 (blocks 506, 508, 510).

At block 502, the method 500 comprises determining (calculating) a first range estimate indicative of a first range travelable by a vehicle in dependence on a first estimation method. The first estimation method is based on a previous distance travelled. The previous distance may be predetermined or user-specified. The previous distance may be a long distance, of the order of thousands of kilometres, such as 7000km. The first estimation method may be based on the average prior energy consumption over the previous distance, for example over the whole 7000km. The average prior energy consumption may be obtained from memory or elsewhere. The range estimate may be extrapolated based on the average prior energy consumption rate and current state of charge.

Due to the long averaging distance, the first range estimate is relatively unaffected by current or recent changes in driving behaviour, and is less volatile. A large previous distance travelled typically covers a balance of long and short past journeys, and hot and cold days, for a typical 10 driver. Therefore, the driver is given a consistent indication of the range capabilities of the vehicle 1, to start with.

Fig 6 illustrates range (y-axis) against distance travelled (x-axis). Fig 6 indicates the indicated (predicted) range of the first calculated range, with a 7000km memory (prior interval size). The indicated range remains close to the actual range and does not fall sharply even if the driver's journey frequency is biased towards short journeys as shown in Fig 3.

At block 504, the method 500 comprises a second range estimate indicative of a second range travelable by the vehicle 1 in dependence on a second estimation method. The second estimation method is based on a portion of the previous distance travelled, rather than the whole previous distance. The second estimation method may be based on the average prior energy consumption over the portion of the previous distance travelled by the vehicle. The portion of the previous distance may be less than half of the distance used for determining the first range estimate. The portion may be approximately 1000km if the previously-used distance was at least 2000km, for example. The portion may extend back from a current or most recent time or data point of the monitored, representing energy consumption over the most recent 1000km.

Fig 6 illustrates the indicated range of the second calculated range, with a 1000km memory (prior distance). The indicated range is more volatile than the 7000km range.

At blocks 506, 508 and 510, the method 500 comprises selectively outputting the first range estimate or the second range estimate in dependence on distance travelled or travelable by the vehicle 1. The distance may be relative to a journey start or vehicle start, or since the energy storage means 14 was last charged. The selective output may change from outputting the first range estimate (block 508) to outputting the second range estimate (block 510) in dependence on a threshold distance travelled or travelable by the vehicle 1. Decision block 506 may determine whether the threshold distance is passed. The selective output decision block 506 may be configured such that the first range estimate is output before the second range estimate. In some, but not necessarily all examples, the change from the first range estimate to the second range estimate may be a discrete transition.

Fig 6 shows a 'first transition' of the range estimate provided to the HMI 214, based on the method 500. The first transition may be automatic or semi-automatic, based on distance travelled or travelable by the vehicle 1. In a first implementation, the threshold distance travelled by the vehicle 1 is in the order of tens of kilometres, and may be less than 50 kilometres. In another implementation, the threshold distance travelable by the vehicle 1 is in the order of more than a hundred kilometres remaining, as indicated by at least one of the range estimation methods.

Fig 5B illustrates a further method 520 for controlling range calculation of a vehicle 1. The method is computer-implemented. The method 520 may be performed by the control system 200. The method 520 at least comprises: receiving state of charge data indicative of a state of charge of the energy storage means 14 (block 521); determining a first calculated energy consumption of the vehicle 1 using a first estimation method (block 522); determining a second calculated energy consumption of the vehicle 1 using a second different estimation method (block 524); determining a range estimate indicative of a range travelable by the vehicle 1, in dependence on the first calculated energy consumption of the vehicle 1, the second calculated energy consumption of the vehicle, and the state of charge data (block 526); and outputting the range estimate (block 528).

In some examples, the method 520 is performed after the method 500, wherein the method 500 represents a first transition (first change of estimation method) and the method 520 represents a second transition (second change of estimation method) later in the journey.

At block 521, the method 520 comprises receiving state of charge data indicative of a state of charge of the energy storage means 14. The state of charge may be a current state of charge, for example.

At block 522, the method 520 comprises determining a first calculated energy consumption of the vehicle 1 using a first estimation method. The first calculated energy consumption may comprise the average prior energy consumption over a previous distance travelled by the vehicle 1. The previous distance may be hundreds or more kilometres, such as approximately 1000km. If the method 520 is performed after the method 500 as a second transition, then block 522 may be the same operation as block 504, except the estimation method would be regarded as a 'second' estimation method, based on 'second' calculated energy consumption.

At block 524, the method 520 comprises determining a second calculated energy consumption of the vehicle 1 using a second different estimation method. The second calculated energy consumption may comprise the average prior energy consumption over a portion of the previous distance travelled by the vehicle 1. The portion may be less than half of the distance used in block 522, such as approximately 150km. If the method 520 is performed after the method 500, then block 524 produces a 'third' calculated energy consumption of the vehicle 1, based on 'third' calculated energy consumption.

At block 526, the method 520 comprises determining a range estimate indicative of a range travelable by the vehicle 1, in dependence on the first calculated energy consumption of the vehicle 1, the second calculated energy consumption of the vehicle, and the state of charge data. At block 528, the range estimate is output to HMI 214.

Initially, the range estimate is dependent on the energy consumption of the vehicle 1 calculated at block 522. This range estimate represents the '1000km' range in Fig 6. However, a transition of block 526 then occurs. The dependency of the range estimate on the energy consumption calculated by block 522 and on the energy consumption calculated by block 524 changes, based on the state of charge data. After the transition, the range estimate is dependent on the energy consumption calculated by block 524. For example, the range estimate may be based on average energy consumption over the past 150 kilometres. The transition is controlled by the depletion of state of charge.

The transition may be a continuous variation of the dependency over a range of the state of charge. The transition may commence at a state of charge having a value of 50% or lower, and 5% or higher. Therefore, in the illustrated examples the transition commences close to battery depletion. Battery depletion may occur towards the end of a journey, however this is not always the case, for example in HEVs which have small traction batteries then switch to an ICE. In Fig 6, the transition is labelled as a 'second transition', which occurs when state of charge is low.

The transition may be a blend transition. During the transition, the range estimate may be a blended value dependent on both the energy consumption calculated by block 522 and the energy consumption calculated by block 524. The function of the transition is such that as the state of charge of the energy storage means decreases, the dependency of the range estimate on the energy consumption calculated by block 522 decreases, and the dependency of the range estimate on the energy consumption calculated by block 524 increases. It would be appreciated that the range estimate may always be partially blended, including before and after the transition.

Applying the methods 500, 520 together results in the graph of Fig 6. The range estimate (dashed line -'actual prediction') is initially smooth and consistent, following the actual range capability (solid line). After the first transition, the range estimate is more volatile and accurate to a recent driving context. After the second transition, the range estimate is even more volatile and accurate to a very recent driving context. This provides a good balance between consistency, accuracy, and an estimation of true range capabilities assuming the driver regularly charges their vehicle between short journeys.

Although Fig 6 represents a range estimate based on three different estimation methods (e.g. previous distances), the concepts described herein apply generally to two or any greater number of estimation methods.

In the above methods 500, 520, the calculations may be updated continuously/periodically by looping the method 500.

It would be appreciated that the specific blocks of the methods 500, 520 are not the only way of achieving the kind of result shown in Fig 6. In alternative implementations from the above, the transitions do not start at specific thresholds, but instead the indicated range is always a blend of range estimates calculated by the estimation methods.

Although in the above examples the transitions are controlled by distance travelled or travelable (block 506) or state of charge (block 526), the transitions could be controlled by a different variable in some implementations. Examples of other variables include: elapsed time of the journey; temperature of the energy storage means; vehicle cabin temperature; temperature of the electric traction motor; or ambient temperature. Temperatures can have a significant effect on energy consumption rate, resulting in the curve shown in Fig 3. According to an aspect of the invention the transition(s) may be controlled by one or more of the above variables, reaching a threshold value for example.

For purposes of this disclosure, it is to be understood that the controller(s) described herein can each comprise a control unit or computational device having one or more electronic processors. A vehicle 1 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 Figs 5A and 5B may represent steps in a method and/or sections of code in the computer program 208. 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.

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. For example, the examples may apply to non-electric vehicles. However, the examples are particularly useful for EVs/HEVs. Range anxiety is greater than non-electric vehicles. Further, EVs and HEVs are usually charged regularly between short journeys unlike combustion-engined vehicles. Such users of electric vehicles will want to know the true range capability for a long journey, and not a range capability that assumes short, inefficient journeys until depletion.

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 endeavoring 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

CLAIMS1. A control system for controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and energy storage means, the control system comprising one or more controllers, wherein the control system is configured to: determine a first range estimate indicative of a first range travelable by the vehicle in dependence on a previous distance travelled by the vehicle; determine a second range estimate indicative of a second range travelable by the vehicle in dependence on a portion of the previous distance travelled; and selectively output the first range estimate or the second range estimate in dependence on distance travelled or travelable by the vehicle.
2. The control system of claim 1, wherein the selective output is configured to change from outputting the first range estimate to outputting the second range estimate in dependence on a threshold distance travelled or travelable by the vehicle on the journey.
3. A control system for controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and energy storage means, the control system comprising one or more controllers, wherein the control system is configured to: receive state of charge data indicative of a state of charge of the energy storage means; determine a first calculated energy consumption of the vehicle using a first estimation method; determine a second calculated energy consumption of the vehicle using a second different estimation method; determine a range estimate indicative of a range travelable by the vehicle in dependence on: the first calculated energy consumption of the vehicle, the second calculated energy consumption of the vehicle, and the state of charge data; and output the range estimate.
4. The control system of claim 1, 2 or 3, wherein the one or more controllers collectively comprise: at least one electronic processor having an electrical input for receiving information; 17 and at least one electronic 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 cause the control system to control the determining and the output.
5. The control system of claim 3, wherein the control system is configured to control a change in the dependency of the range estimate on the first calculated energy consumption and on the second calculated energy consumption in dependence on the state of charge data.
6. The control system of claim 5, wherein the change is a continuous variation over a range of the state of charge of the energy storage means.
7. The control system of claim 3, 5 or 6, wherein as the state of charge of the energy storage means decreases, the dependency of the range estimate on the first calculated energy consumption decreases, and the dependency of the range estimate on the second calculated energy consumption increases.
8. The control system of claim 3, 5, 6 or 7, wherein the first estimation method is based on prior energy consumption over a previous distance travelled by the vehicle and the second estimation method is based on prior energy consumption over a portion of the previous distance travelled by the vehicle.
9. The control system of claim 8, wherein the first estimation method is based on an average prior energy consumption over the previous distance travelled by the vehicle, and wherein the second estimation method is based on an average prior energy consumption over the portion of the previous distance travelled by the vehicle.
10. The control system of claim 8 or 9, wherein the portion of the previous distance travelled is less than half the total previous distance travelled by the vehicle indicated by the vehicle distance data.
11. A system comprising the control system of any preceding claim, and a human-machine interface for providing feedback to a user of the vehicle, wherein the human-machine interface is configured to receive the output from the control system.
12. A vehicle comprising the control system of any one of claims 1 to 11 or the system of claim 11.
13. A method of controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and an energy storage means, the method comprising: determining a first range estimate indicative of a first range travelable by the vehicle in dependence on a previous distance travelled by the vehicle; determining a second range estimate indicative of a second range travelable by the vehicle in dependence on a portion of the previous distance travelled; and selectively outputting the first range estimate or the second range estimate in dependence on distance travelled or travelable by the vehicle.
14. A method of controlling range calculation of a vehicle, the vehicle comprising an electric traction motor and an energy storage means, the method comprising: receiving state of charge data indicative of a state of charge of the energy storage means; determining a first calculated energy consumption of the vehicle using a first estimation method; determining a second calculated energy consumption of the vehicle using a second different estimation method; determining a range estimate indicative of a range travelable by the vehicle, in dependence on the first calculated energy consumption of the vehicle, the second calculated energy consumption of the vehicle, and the state of charge data; and outputting the range estimate.
15. Computer software that, when executed, is arranged to perform a method according to claim 13 or 14.