WO2014120849A2

WO2014120849A2 - System and method for inhibiting a driver of an electric vehicle from being stranded

Info

Publication number: WO2014120849A2
Application number: PCT/US2014/013705
Authority: WO
Inventors: Gary J. Gloceri
Original assignee: Magna E-Car Systems Of America, Inc.
Priority date: 2013-01-30
Filing date: 2014-01-30
Publication date: 2014-08-07
Also published as: WO2014120849A3

Abstract

A method of inhibiting a driver of an electric vehicle from being stranded along a route is provided. The method includes determining a plurality of routes to a selected destination, and determining a predicted total energy consumption associated with each route based on elevation changes determined to take place along each route, and based on actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades. In a particular embodiment the determination may further be based on information relating to speed limits along the route.

Description

SYSTEM AND METHOD FOR INHIBITING A DRIVER OF AN ELECTRIC VEHICLE

FROM BEING STRANDED

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The subject PCT application claims priority to U.S. Provisional Serial No. 61/758,387 filed on January 30, 2013, the entire disclosure of which is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to electric vehicles and more particularly to systems and methods for inhibiting a driver of an electric vehicle from being stranded.

BACKGROUND

[0003] In the field of electric vehicles, it has been proposed to provide a system to notify a driver of an electric vehicle of the amount of range that the vehicle has remaining, based on the amount of charge in the battery pack of the vehicle. However, the accuracy of these proposed systems is not clear. As such, range anxiety remains a concern for the driver of an electric vehicle, particularly in today's environment, where there are relatively few charging stations available for such vehicles.

[0004] There is consequently a need for a system and method of better reducing range anxiety for a driver of a vehicle, and of more reliably inhibiting a driver of an electric vehicle from being stranded.

SUMMARY

[0005] In an aspect, a method of inhibiting a driver of an electric vehicle from being stranded is provided. The method includes:

a) determining a current position for the vehicle;

b) receiving an input of a selected destination;

c) determining a plurality of routes to the selected destination;

d) determining a predicted total energy consumption associated with each route based on elevation changes determined to take place along each route, and based on information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades; e) selecting one of the routes based on a comparison of the predicted total energy consumptions; and f) notifying the driver of the selection made in step e).

[0006] Optionally, the determination made in step d) is based on any positive changes in elevation determined to take place along each route and any negative changes in elevation determined to take place along each route.

[0007] Optionally, the elevation changes determined to take place along each route are determined based on topographic data stored onboard the vehicle.

[0008] Optionally, the elevation changes determined to take place along each route are retrieved from the internet via a wireless internet connection onboard the vehicle.

[0009] Optionally, the determination made in step d) is further based on an estimate of the speed of the vehicle along each route.

[0010] Optionally, the estimate of the speed of the vehicle along each route is based on information relating to speed limits along each route.

[0011] Optionally, the actual power consumption data includes power consumption data for a plurality of grades and at a plurality of speeds on each grade.

[0012] Optionally, the actual power consumption data is stored in memory on the vehicle.

[0013] Optionally, the actual power consumption data is based at least in part on data collected during operation of another example of the vehicle during development of the vehicle.

[0014] Optionally, wherein the information related to actual power consumption data is updated based on data collected during operation of the vehicle.

[0015] Optionally, the determination made in step d) is further based on the operational state of at least one electrical load on the vehicle. [0016] Optionally, for at least one route, the method includes determining whether or not the vehicle can reach the selected destination based on a comparison of the predicted total energy consumption for the at least one route with the total energy stored in the battery pack.

[0017] Optionally, for each route, step d) includes:

g) dividing the route into a plurality of route segments each having an associated grade and speed; and

h) determining a predicted energy consumption for the vehicle on each route segment based on the associated grade and speed using the actual power consumption data.

[0018] Optionally, the method further comprises providing the driver with at least one of: an indication of the amount of power being consumed by the vehicle relative to a predicted power consumption on a current route segment, and an indication of a current overall energy consumption of the vehicle on the route relative to a predicted current overall energy consumption for the vehicle on the route.

[0019] In another aspect, a system for inhibiting a driver of an electric vehicle from being stranded is provided. The system includes an input device, an output device, a GPS sensor, a control system including a processor and a memory. The memory contains information related to information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades. The control system is programmed to:

a) determine a current position for the vehicle;

b) receive an input of a selected destination;

c) determine a plurality of routes to the selected destination;

d) determine a predicted total energy consumption associated with each route based on elevation changes determined to take place along each route, and based on the information related to actual power consumption data; e) select one of the routes based on a comparison of the predicted total energy consumptions; and f) notify the driver of the selection made in step e).

[0020] Optionally, the output device includes a display.

[0021] Optionally, the determination made in step d) is based on any positive changes in elevation determined to take place along each route and any negative changes in elevation determined to take place along each route.

[0022] Optionally, the elevation changes determined to take place along each route are determined based on topographic data stored onboard the vehicle.

[0023] Optionally, the elevation changes determined to take place along each route are retrieved from the internet via a wireless internet connection onboard the vehicle.

[0024] Optionally, the determination made in step d) is further based on an estimate of the speed of the vehicle along each route.

[0025] Optionally, the estimate of the speed of the vehicle along each route is based on information relating to speed limits along each route.

[0026] Optionally, the actual power consumption data includes power consumption data for a plurality of grades and at a plurality of speeds on each grade.

[0027] Optionally, the actual power consumption data is based at least in part on data collected during operation of another example of the vehicle during development of the vehicle.

[0028] Optionally, wherein the actual power consumption data is updated based on data collected during operation of the vehicle.

[0029] Optionally, the determination made in step d) is further based on the operational state of at least one electrical load on the vehicle.

[0030] Optionally, for at least one route, the control system is further programmed to determine whether or not the vehicle can reach the selected destination based on a comparison of the predicted total energy consumption for the at least one route with the total energy stored in the battery pack.

[0031] Optionally, for each route, the control system is programmed to carry out step d) at least in part by: g) dividing the route into a plurality of route segments each having an associated grade and speed; and

[0032] Optionally, wherein the control system is further programmed to provide the driver with at least one of: an indication of the amount of power being consumed by the vehicle relative to a predicted power consumption on a current route segment, and an indication of a current overall energy consumption of the vehicle on the route relative to a predicted current overall energy consumption for the vehicle on the route.

[0033] In yet another aspect, a method of predicting the energy consumption of an electric vehicle to reach a selected destination along a selected route is provided, comprising:

a) receiving an input of a selected destination;

b) determining a route to the selected destination;

c) dividing the route into a plurality of route segments each having an associated grade and speed;

d) determining a predicted energy consumption for the vehicle on each route segment based on the associated grade and speed using information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades;

e) determining a predicted energy consumption for the vehicle on the route based on the predicted energy consumption for the vehicle on each route segment; and

f) notifying the driver of at least one of: the determination made in step e), and whether or not the vehicle has sufficient energy stored in a battery to reach the selected destination based on the determination made in step e).

[0034] In yet another aspect, a system for predicting the energy consumption of an electric vehicle to reach a selected destination along a selected route is provided, comprising: an input device;

an output device;

a GPS sensor; and

a control system including a processor and a memory, wherein the memory contains information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades, and wherein the control system is programmed to:

a) receive an input of a selected destination;

b) determine a route to the selected destination;

c) divide the route into a plurality of route segments each having an associated grade and speed;

d) determine a predicted energy consumption for the vehicle on each route segment based on the associated grade and speed using information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades;

e) determine a predicted energy consumption for the vehicle on the route based on the predicted energy consumption for the vehicle on each route segment; and f) notify the driver of at least one of: the determination made in step e), and whether or not the vehicle has sufficient energy stored in a battery to reach the selected destination based on the determination made in step e).

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present disclosure will now be described by way of example only with reference to the attached drawings, in which:

[0036] Figure 1 is a perspective view of an electric vehicle with a navigation system;

[0037] Figure 2 is a magnified view of an image on a display in the vehicle shown in Figure 1 , showing a plurality of routes to a destination;

[0038] Figure 3 is a magnified view of another image on the display from the vehicle shown in Figure 1 , showing a plurality of routes to another destination;

[0039] Figure 4 is a graph showing the results of testing the vehicle shown in Figure 1 on a plurality of grades and at a plurality of speeds; [0040] Figure 5 shows a bar graph that illustrates the vehicle's power consumption relative to a predicted power consumption;

[0041] Figure 6 is a flow diagram illustrating a method of operation of a control system for the vehicle shown in Figure 1 ; and

[0042] Figure 7 is a flow diagram illustrating another method of operation of a control system for the vehicle shown in Figure 1.

DETAILED DESCRIPTION

[0043] In this specification and in the claims, the use of the article "a", "an", or "the" in reference to an item is not intended to exclude the possibility of including a plurality of the item in some embodiments. It will be apparent to one skilled in the art in at least some instances in this specification and the attached claims that it would be possible to include a plurality of the item in at least some embodiments.

[0044] Reference is made to Figure 1 , which shows a vehicle 10 with a chassis 11 , an electric traction motor 12, a battery pack 14, a vehicle control system 16, and an in-cabin display 18.

[0045] The vehicle 10 is equipped with a navigation system 20 which includes a navigation system control unit 22, and some form of storage device 24 for storing map data with which to display a map of the vehicle's surroundings on the display 18. The storage device 24 may be a DVD reader and a removable DVD of map data. Alternatively, the storage device 24 could be a hard drive containing map data. The map data may include the positions of roads, highways, etc, and also other information. For example, the map data may include elevation data (i.e. topographic information). Additionally, the map data may include speed limit data for the roads, highways, etc that are included. Instead of having the elevation data and speed limit data stored in storage device 24, this data may be stored elsewhere (e.g. on a server that is remote from the vehicle 10 and may be retrieved by the navigation system 20 via a wireless (e.g. cellular) internet connection that may be provided on the vehicle 10. This data is discussed in further detail below.

[0046] The control system 16 shown may include one control unit or a plurality of control units. A single control unit is shown for convenience in Figure 1. The control system 6 includes a processor 16a and a memory 16b that is accessed by the processor 16a.

[0047] An input device 26 (such as, for example, a touch screen that is combined with the display 18) may be provided for inputting information such as a desired destination, shown at 27 in Figure 2, which is received by the navigation system control unit 22. The navigation system control unit 22 may be programmed to select one or more routes, shown at 29, to reach the selected destination 27. In the exemplary embodiment shown in Figure 2, the navigation system control unit 22 has selected a first route 29a, a second route 29b and a third route 29c. The one or more routes 29 may be selected based on various factors, such as, shortest distance, shortest travel time, avoidance of highway travel, or any other suitable factors. For example, a route 29 may, in at least some instances, be entirely selected by the driver.

[0048] For at least one selected route 29, the vehicle control system 16 may be programmed to determine the total predicted energy consumption associated with the route 29. In embodiments wherein the vehicle control system 16 is programmed to determine the total predicted energy consumption associated with each of a plurality of routes 29, the control system 16 may be programmed to determine which route 29 has the lowest predicted energy consumption and to notify the driver of the determination. Additionally or alternatively, the vehicle control system 16 may be programmed to determine whether or not there is enough charge left in the battery pack 14 to reach the selected destination and to notify the driver of the determination. The aforementioned determinations by the vehicle control system 16 may be based on a current, three-coordinate position for the vehicle (e.g. including latitude, longitude and elevation), which is shown graphically at 28 on the display 18 shown in Figure 2, elevation and distance data associated with each route 29, and actual power consumption data associated with the vehicle 10 during travel on a plurality of grades at a plurality of speeds. For example, the vehicle control system 16 may initially check route 29a, and may then check route 29b and then route 29c. After checking the routes 29a, 29b and 29c, the vehicle control system 16 may be programmed to notify the driver which routes 29 would be within the vehicle's range and which are not, and may further notify the driver which route 29 is the most energy efficient.

[0049] The steps involved in determining whether the vehicle 10 has sufficient charge in the battery pack 14 to reach the selected destination 27 on a particular route 29 are described hereinbelow. The vehicle control system 16 may determine the amount of charge remaining in the battery pack 14. This step may be carried out using any suitable means. The vehicle control system 16 may be programmed to determine a current position 28 for the vehicle 10 using any suitable means, such as a GPS sensor 26 onboard the vehicle 10. The current position 28 for the vehicle 10 includes three coordinates so as to specify the vehicle's position 28 in three dimensions. The three coordinates may be, for example, latitude, longitude and altitude, (which may also be referred to as elevation). The vehicle control system 16 may obtain all three coordinates from the GPS sensor 26. Alternatively, the vehicle control system 16 may obtain the latitude and longitude from the GPS sensor 26 and may obtain the elevation coordinate from some other source, such as by sending the latitude and longitude coordinates to the navigation system, so that the navigation system can determine the elevation of the vehicle 10 from the map data.

[0050] Referring to Figure 2, in an embodiment, the vehicle control system 16 then breaks the route up into a plurality of segments based on changes to the grade of the route, so that each segment has a single grade and a length. For example, referring to Figure 2, the vehicle control system 16 breaks route 29a up into segments 32a, 32b, and 32c based on changes to the grade of the route, so that each segment 32a, 32b, and 32c has a single or similar grade and a length. The vehicle control system 16 determines the predicted energy consumption to drive along each segment 32a, 32b, and 32c and adds up the predicted energy consumptions to determine the total predicted energy consumption for the route. The vehicle control system 16 then compares this total predicted energy consumption to the amount of energy remaining in the battery pack 14 to determine whether there is enough charge in the battery pack 14 to reach the selected destination along that route. The vehicle control system 16 may then notify the driver of the vehicle 10 of the result of the determination. The vehicle control system 16 may notify the driver of how much battery charge would remain after reaching the destination.

[0051] When breaking a route 29 into segments, such as breaking route 29a into segments 32a, 32b, and 32c, the vehicle control system 16 may determine that a segment ends wherever the grade changes relatively abruptly (i.e. beyond a selected level of abruptness). In some parts of a route 29 however, the change in grade is relatively gradual. In such cases, the vehicle control unit 29 may determine that a segment ends after a selected distance and may determine the grade of that segment to be the average grade along that distance.

[0052] Vehicle speed is a factor that impacts power consumption of any vehicle. When determining the predicted energy consumption needed to reach the selected destination the vehicle control system 16 may assume that the vehicle speed will be whatever the speed happens to be at the time that the vehicle control system 16 determines the predicted energy consumption amounts.

[0053] Alternatively, the vehicle control system 16 may estimate the vehicle's speed along different portions of the route 29. As an example, using the speed limit data associated with the route, the vehicle control system 16 may estimate the vehicle's speed at any point along the route to be a selected fraction of the posted speed limit at that point. The selected fraction may be 100% (i.e. the vehicle control system 16 may estimate that the vehicle 10 will drive at the speed limit). The selected fraction may be greater than 100%, or may be less than 100%. In such an embodiment, the vehicle control system 16 may divide the route up into a plurality of segments based on changes in grade and on speed limit. In other words, the vehicle control system 16 may end a segment and start a new segment whenever there is a change in either grade or speed limit. In this embodiment, the determination by the vehicle control system 16 may be based on speed limit data associated with that route in addition to being based on elevation data. The vehicle control system 16 may use fixed guidelines as to what fraction to use (e.g. the control system 16 may always use a set fraction of the speed limit values). Alternatively, the vehicle control system 16 may compare the actual vehicle speed with the posted limit at one or more times during use of the vehicle 10 so that the vehicle control system 16 can determine a suitable fraction to apply for each portion of the route. As yet another alternative, the control system 16 may store previous speeds driven by the vehicle 10 on a particular route 29.

[0054] The control system 16 may modify the estimate of the speed of the vehicle 10 based on sensing one or more events, such as for example, activation of an anti-lock braking system on the vehicle 10. This may be interpreted by the control system 16 to mean that the road conditions are slippery and that the vehicle 10 will be driving more slowly along the route 29 than would be expected based on the posted speed limits. The control system 16 could also interpret ambient temperature data from an ambient temperature sensor (not shown) onboard the vehicle 10.

[0055] The vehicle 10 may be configured to determine other factors that impact the speed at which the vehicle 10 will travel on certain segments of the route 29. For example, the control system 16 may be configured to access traffic data websites over a wireless (e.g. cellular) network so as to locate points along the route 29 where traffic congestion is high, resulting in reduced vehicle speed. In another example, the control system 16 may be configured to determine any points along the route 29 where there is construction that would result in a reduction in vehicle speed.

[0056] Figure 3 shows another example of an image that could appear on the display 18. In Figure 3 a particular route 29 is shown to a destination 27. Optionally, an elevation profile of the route 29 may be represented as a curve 80 in a region 82 of the image. A particular segment 29h is identified in both the route 29 and in the curve 80.

[0057] The determination by the vehicle control system 16 as to whether the battery pack 14 has enough charge for the vehicle 10 to reach the selected destination may further be based on additional factors, such as the operational state of certain electrical loads, such as the air conditioning system for the vehicle 10. For example, the vehicle control system 16 may determine whether the air conditioning system is on or off. Referring to Figure 1 , the air conditioning system is shown at 30. If the air conditioning system is on, the vehicle control system 16 may further determine the level of cooling at which the air conditioning system 30 is being operated (e.g. the vehicle control system 16 may determine the speed of the compressor, and may determine the power consumption associated with the compressor based on the determined compressor speed). Other battery loads may be vehicle lights or other electrically powered devices.

[0058] The actual power consumption data associated with the vehicle during travel on a plurality of grades at a plurality of speeds may be obtained by a plurality of methods. In a particular example, prior to release of production copies of the vehicle 10 into the marketplace, tests may be carried out on the actual vehicle 10, or on another example of the vehicle 10 (e.g. a test model of the vehicle 10 during vehicle development) to determine actual power consumption data over a selected range of grades and over a selected range of vehicle speeds. The selected range of grades may include only uphill (i.e. positive) grades, or both uphill (i.e. positive) grades and downhill (i.e. negative) grades. For greater clarity, the power consumption on a downhill grade may be a negative power consumption if the vehicle 10 is equipped to recoup the rolling energy (e.g. via regenerative braking) of the vehicle 10 and use the rolling energy to charge the battery. Other sources of regenerative braking energy may be stoplights or stop signs that may be known by the navigation system 20 to be along the route 29. Other sources may include, for example, portions of the route 29 that represent a large reduction in the posted speed limits. Information relating to the actual power consumption data derived from the aforementioned testing may be stored in a table in memory onboard each example of the vehicle 10 that leaves the assembly plant. The information stored in the table may be the actual power consumption data itself. Alternatively, the information may be in the form of values that are derived from but not identical to the actual power consumption data.

[0059] To assist the vehicle control system 16 in determining the predicted energy consumption along a particular route 29, the control system 16 can use the elevation data to determine grades along which the vehicle 10 will travel, and can use the map data pertaining to road positions to determine the distances the vehicle 10 will travel on each grade. In embodiments wherein the map data includes speed limit information, the vehicle control system 16 can also estimate the speed at which the vehicle 10 will travel along each portion of the route to more accurately estimate the predicted energy consumption. [0060] As noted above, in an alternative embodiment, instead of testing a test model of the vehicle 10 and providing each production copy of the vehicle 10 with the table of power consumption values. The vehicle control system 16 could also be programmed to obtain actual power consumption data for the actual vehicle 10 during use by the vehicle owner. For example, the vehicle control system 16 may use GPS sensor data to determine when the vehicle 10 is on a non-zero grade (by continuous checking of the vehicle's elevation), and can measure the energy drain on the battery pack 14 while the vehicle 10 is on that grade. Once the grade changes, or a selected period of time has passed, the vehicle control system 16 may stop measuring the power drain and may store power consumption information in a table based on the measured actual power consumption data, along with the vehicle speed and the value of the grade. In this way, the vehicle control system 16 can populate the table during use of the vehicle 10 when the vehicle 10 encounters different grades and travels along them at different speeds, and the power consumption data stored in memory can thus be specific to that particular vehicle 10.

[0061] In another embodiment, the vehicle 10 may be initially provided with a table populated with values based on actual power consumption data obtained from use of a test model of the vehicle during vehicle development, and during use of the vehicle 10 the control system 16 may update values in the table based on a determination of actual power consumption data for the actual vehicle on selected grades at selected speeds. Updating a value in the table may entail replacing the value in the table with currently determined data. Alternatively, updating a value in the table may entail taking an average (e.g. a moving average) of an actual power consumption data on a grade at a selected speed and the current value in the table. Updating a value in the table may alternatively entail storing maximum historical power consumption on a selected grade at a selected speed. Updating a value in the table may alternatively entail storing a minimum historical power consumption on a selected grade at a selected speed.

[0062] Whether the table is populated with values based on data collected from a test model of the vehicle, values based on data collected during use of the actual vehicle belonging to the driver, or values that are based on both data collected from a test model and data collected during use of the actual vehicle, the table may optionally be refined to contain power consumption data taking into account the operational state of certain electrical loads, such as the air conditioning system, the heating system, the headlights or other loads. For example, the table may include data relating to power consumption on a particular grade at a particular speed while the air conditioning system is off, and separate data relating to power consumption on that particular grade at that particular speed while the air conditioning system is on. As a result, the control system 16 can more accurately predict the power consumption of the vehicle 10 along the route 29.

[0063] Figure 4 shows a graphical illustration of some of the data that could be stored onboard the vehicle 10 (i.e. in the memory 16b that is part of the control system 16). As can be seen, a plurality of curves 84a-84m are shown, each of which represents the power consumption of the vehicle 10 when driving at a range of speeds on a particular grade. The curve 84a represents the power consumption over a range of speeds while being driven on a 6 percent grade. The curve 84b represents the power consumption over a range of speeds while being driven on a 5 percent grade, and so on, down to a grade of -6 percent. For the particular route segment 29h shown in Figure 3, the control system 16 may determine that the segment 29h has an average grade of 3.2 percent, and may determine that the vehicle driver is likely to drive on that segment 29h at an average speed of about 30mph. The distance of the segment 29h may be determined to be about 0.69 miles. The control system 16 may then interpolate between the data associated with the curve 84d (a 4 percent grade) and 84c (a 3 percent grade) and may determine that the power consumption is about 4000W. The energy consumption along that route segment 29h may be determined by the control system 16. The energy consumption, in Wh (Watt hours) may be determined by the formula ENERGY = POWER x SPEED / DISTANCE. In the example provided, the energy consumed is approximately 92 Wh for the segment 29h.

[0064] As described herein, the vehicle control system 16 is programmed to notify the driver of the vehicle 10 as to whether there is sufficient charge in the battery pack 14 to reach a selected destination, or as to what the range of the vehicle 10 is. The notification may be carried out via one or more output devices. For example, the notification may be done via a visual output device, such as the display 18, for example. Additionally or alternatively, the notification may be done using a spoken language message, or using a chime, a beep or the like, via an audio output device, such as the speaker system in the vehicle 10.

[0065] The vehicle 10 may further include a combustion engine (not shown). The combustion engine, if provided, may be used in parallel with the electric motor 12 to assist in driving the one or more driven wheels of the vehicle 10. Alternatively the engine may be used only to charge the battery pack 14, or the engine may be used sometimes in parallel with the electric motor 12 and sometimes to charge the battery pack 14.

[0066] In a situation where the vehicle control system 16 determines that the vehicle 10 does not have sufficient charge in the battery pack 14 to reach the selected destination 27 along a selected route 29, the vehicle control system 16 may be programmed to indicate to the driver (e.g. via the display 18) what distance along the selected route 29 that the vehicle 10 can travel.

[0067] In some situations, there may be a selected route 29 inputted into the navigation system 20 or may be determined by the navigation system 20 even though there is no particular destination 27 selected. In such situations also, the vehicle control system 16 may be programmed to indicate to the driver (e.g. via the display 18) what distance along the selected route 29 that the vehicle 10 can travel.

[0068] In the embodiments described herein, certain method steps are described before other method steps. For example, the step of determining the current position 28 of the vehicle is described before the step of determining a current level of charge in the battery pack 14 of the vehicle 10. It will be understood however, that the particular order in which they are described is not intended to limit the order in which the steps occur. It will be understood that the vehicle control system 16 could determine the level of charge in the battery pack 14 before the control system 16 determines the current position 28 of the vehicle 10. As another example, the control system could receive an input of a selected destination prior to determining a current position 28 for the vehicle 10 and/or before determining the level of charge in the battery pack 14. [0069] The control system 16 may be configured to display an indication of the amount of power being consumed by the vehicle 10 relative to the amount of power that was predicted to be consumed on the current route segment. This may be provided in any suitable way, (e.g. in the form of a bar graph 86 on the display 18 as shown in Figure 5). Additionally, the control system 16 may be configured to display an indication of the overall energy consumption of the vehicle 10 relative to the predicted overall energy consumption for the vehicle 10 thus far along the route 29 (e.g. in the form of a second bar graph 88 on the display as shown in Figure 5). Providing one or both of these bar graphs 86 and 88 permits the driver of the vehicle 10 to assess whether there is a significant risk that the prediction made by the control system 16 that the vehicle will reach the destination 27 is in error. The control system 16 may itself also be capable of updating the prediction and can be configured (e.g. programmed) to inform the driver if the vehicle's power consumption is so much higher than predicted that the vehicle 10 will not reach the destination prior to depletion of the battery pack 14.

[0070] In the example shown in Figure 5, the actual current power consumption of the vehicle 10 is lower than that predicted, but the actual overall energy consumption thus far on the chosen route 29 is higher than that predicted.

[0071] Optionally, charging stations that are along or near the route 29 may be displayed on the display 18 that would be reachable by the vehicle 10 based on the current state of charge (SOC) of the battery pack 14. In particular, such charging stations could be displayed at all times or when the control system 16 determines that the vehicle 10 is at risk of not reaching the selected destination 27 based on the current SOC of the battery pack 14.

[0072] Figure 6 shows a flow diagram illustrative of a method 100 of operating the control system 16. At step 102, the control system 16 obtains (e.g. receives via the touch screen interface 26) input relating to a selected destination. At step 104, the control system 16 determines a route to the destination. This may be by way of an input by the vehicle driver, or by an automated selection process carried out by the control system 16, or by a combination of the two (e.g. the system 16 selected a small number of optional routes and the driver selects one of them) as described above.

[0073] At step 106 the route 29 is parsed into one or more route segments, based on any suitable criteria, such as by changes in speed limit, changes in elevation and/or any other suitable criteria.

[0074] At step 108, the energy utilization is determined for each segment and for the overall route 29 based on the determinations for the segments. This may be carried out by determining the energy utilization for each segment separately and by summing the individual determinations.

[0075] At step 1 10, it is determined whether the vehicle can reach the destination 27 based on the state of charge of the battery pack 14 and the energy utilization determined in step 108.

[0076] At step 1 12, if the determination is made that the vehicle 10 cannot reach the destination 27, the driver of the vehicle 10 may be notified by the control system 16 that the destination is unreachable based on the current SOC of the battery pack 14. Optionally, and in particular if the determination is made that the vehicle 10 cannot reach the destination 27, charging stations that are reachable along the route 29 or are reachable even if not on the route 29 may be displayed on a display 18.

[0077] At step 1 14, as the vehicle is being driven towards the destination 27, the control system 16 may display information to the driver that indicates whether or not the vehicle's instantaneous power consumption is greater than or less than that predicted for the current route segment on which the vehicle 10 is being driven. Additionally or alternatively, the control system 16 may display information to the driver that indicates whether or not the vehicle's cumulative energy consumption on the route 29 is greater than or less than that predicted. If, at any time, the control system 16 determines that the vehicle 10 does not have enough charge to reach the destination 27, the control system 16 may notify the driver of this determination. Optionally, the control system 16 may determine the point on the route 29 at which the vehicle 10 will not be able to return to a selected starting point, such as the current position 28, or the point on the route 29 at which the vehicle 10 will not have enough charge to reach a recharging station, and may display one or both of these points on the display 18.

[0078] The methods described herein may be stored in the form of one or more programs in the memory 16b from the control system 16.

[0079] Figure 7 illustrates some of the method steps described above, by which the control system 16 of the vehicle 10 is programmed, so as to inhibit the driver of an electric vehicle from being stranded while operating the vehicle 10. The method is shown at 200. At step 202, the control system 16 determines a current position for the vehicle 10. At step 204, the control system 16 receives an input of a selected destination 28 by the driver. At step 206, the control system 16 determines a plurality of routes 29 to the selected destination 28. At step 208, the control system 16 determines a predicted total energy consumption associated with each route 29 based on elevation changes determined to take place along each route 29, and based on information related to actual power consumption data associated with the vehicle 10 travelling at a plurality of speeds on a plurality of grades. At step 210, the control system 16 selects one of the routes 29 based on a comparison of the predicted total energy consumptions. At step 212, the control system 16 notifies the driver of the selection made in step 210.

[0080] While the above description constitutes a plurality of embodiments of the present disclosure, it will be appreciated that the present disclosure is merely exemplary and thus susceptible to further modification and change without departing from the fair meaning of the accompanying claims.

Claims

CLAIMS: What is claimed:

1. A method of inhibiting a driver of an electric vehicle from being stranded, comprising:

a) determining a current position for the vehicle;

b) receiving an input of a selected destination;

c) determining a plurality of routes to the selected destination;

d) determining a predicted total energy consumption associated with each route based on elevation changes determined to take place along each route, and based on information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades;

e) selecting one of the routes based on a comparison of the predicted total energy consumptions; and

f) notifying the driver of the selection made in step e).

2. A method as claimed in claim 1 , wherein the determination made in step d) is based on any positive changes in elevation determined to take place along each route and any negative changes in elevation determined to take place along each route.

3. A method as claimed in claim 1 , wherein the elevation changes determined to take place along each route are determined based on topographic data stored onboard the vehicle.

4. A method as claimed in claim 1 , wherein the elevation changes determined to take place along each route are retrieved from the internet via a wireless internet connection onboard the vehicle.

5. A method as claimed in claim 1 , wherein the determination made in step d) is further based on an estimate of the speed of the vehicle along each route.

6. A method as claimed in claim 5, wherein the estimate of the speed of the vehicle along each route is based on information relating to speed limits along each route.

7. A method as claimed in claim 5, wherein the information related to actual power consumption data is related to actual power consumption data for a plurality of grades and at a plurality of speeds on each grade.

8. A method as claimed in claim 7, wherein the information related to actual power consumption data is stored in memory on the vehicle.

9. A method as claimed in claim 8, wherein the information related to actual power consumption data is based at least in part on data collected during operation of another example of the vehicle during development of the vehicle.

10. A method as claimed in claim 9, wherein the information related to actual power consumption data is updated based on data collected during operation of the vehicle.

11. A method as claimed in claim 1 , wherein the determination made in step d) is further based on the operational state of at least one electrical load on the vehicle.

12. A method as claimed in claim 1 , further comprising, for at least one route, determining whether or not the vehicle can reach the selected destination based on a comparison of the predicted total energy consumption for the at least one route with the total energy stored in the battery pack.

13. A method as claimed in claim 1 , wherein, for each route, step d) includes: g) dividing the route into a plurality of route segments each having an associated grade and speed; and h) determining a predicted energy consumption for the vehicle on each route segment based on the associated grade and speed using the information related to actual power consumption data.

14. A method as claimed in any one of claims 1 and 13, further comprising providing the driver with at least one of: an indication of the amount of power being consumed by the vehicle relative to a predicted power consumption on a current route segment, and an indication of a current overall energy consumption of the vehicle on the route relative to a predicted current overall energy consumption for the vehicle on the route.

15. A system for inhibiting a driver of an electric vehicle from being stranded, comprising:

an input device;

an output device;

a GPS sensor; and

a) determine a current position for the vehicle;

b) receive an input of a selected destination;

c) determine a plurality of routes to the selected destination;

d) determine a predicted total energy consumption associated with each route based on elevation changes determined to take place along each route, and based on the information related to actual power consumption data;

e) select one of the routes based on a comparison of the predicted total energy consumptions; and

f) notify the driver of the selection made in step e).

16. A system as claimed in claim 15, wherein the output device includes a display.

17. A system as claimed in claim 15, wherein the determination made in step d) is based on any positive changes in elevation determined to take place along each route and any negative changes in elevation determined to take place along each route.

18. A system as claimed in claim 15, wherein the elevation changes determined to take place along each route are determined based on topographic data stored onboard the vehicle.

19. A system as claimed in claim 15, wherein the elevation changes determined to take place along each route are retrieved from the internet via a wireless internet connection onboard the vehicle.

20. A system as claimed in claim 15, wherein the determination made in step d) is further based on an estimate of the speed of the vehicle along each route.

21. A system as claimed in claim 20, wherein the estimate of the speed of the vehicle along each route is based on information relating to speed limits along each route.

22. A system as claimed in claim 20, wherein the actual power consumption data includes power consumption data for a plurality of grades and at a plurality of speeds on each grade.

23. A system as claimed in claim 22, wherein the information related to actual power consumption data is based at least in part on data collected during operation of another example of the vehicle during development of the vehicle.

24. A system as claimed in claim 23, wherein the information related to actual power consumption data is updated based on data collected during operation of the vehicle.

25. A system as claimed in claim 15, wherein the determination made in step d) is further based on the operational state of at least one electrical load on the vehicle.

26. A system as claimed in claim 15, wherein, for at least one route, the control system is further programmed to determine whether or not the vehicle can reach the selected destination based on a comparison of the predicted total energy consumption for the at least one route with the total energy stored in the battery pack.

27. A system as claimed in claim 15, wherein, for each route, the control system is programmed to carry out step d) at least in part by:

28. A system as claimed in any one of claims 15 and 27, wherein the control system is further programmed to provide the driver with at least one of: an indication of the amount of power being consumed by the vehicle relative to a predicted power consumption on a current route segment, and an indication of a current overall energy consumption of the vehicle on the route relative to a predicted current overall energy consumption for the vehicle on the route.

29. A method of predicting the energy consumption of an electric vehicle to reach a selected destination along a selected route, comprising:

a) receiving an input of a selected destination;

b) determining a route to the selected destination;

c) dividing the route into a plurality of route segments each having an associated grade and speed; d) determining a predicted energy consumption for the vehicle on each route segment based on the associated grade and speed using information related to actual power consumption data associated with the vehicle travelling at a plurality of speeds on a plurality of grades;

30. A system for predicting the energy consumption of an electric vehicle to reach a selected destination along a selected route, comprising:

an input device;

an output device;

a GPS sensor; and

a) receive an input of a selected destination;

b) determine a route to the selected destination;