State of charge indication

Abstract

A system for providing a scale (11) of electrical charge of a vehicle battery and a hybrid vehicle comprising such a system comprises a scale (11) of state of charge of the vehicle battery. The scale (11) comprises minimum (14) and maximum (15) parameters and a controller to select the minimum (14) and maximum (15) parameters if the scale (11) in dependence on a battery usage parameter dependent on at least one of a mode of operation of the vehicle, a state of charge of the battery and a state of health of the battery. A display (10) for indicating an amount consists of the scale (11) and an indicator (12) movable with respect to the scale (11). Different scales (11) are provided for different purposes, and are changeable without altering the instant position of the indicator (12). The display (10) may indicate the state of charge of a battery of the hybrid electric vehicle having an internal combustion engine and motor/generator, different scales (11) having maxima (15) corresponding to different nominal or optimum states of charge.

Claims

1. A system for providing a scale of electrical charge of a vehicle battery, the system comprising: a scale of state of charge of the vehicle battery, the scale comprising minimum and maximum parameters; and a controller arranged to display a marker on the scale, the marker indicating the state of charge detected by a detector, wherein the controller is arranged to control the marker to appear on the scale between a displayed first indicator indicating a first permissible minimum state of charge and a displayed second indicator indicating a first permissible maximum state of charge when the vehicle is in a first driving mode; wherein the controller is arranged to control the marker indicating the state of charge detected to appear on the scale between the displayed first and a displayed third indicator when the vehicle is in a second driving mode; wherein the third indicator indicates a second permissible maximum state of charge; wherein the second permissible maximum state of charge is higher than the first permissible maximum state of charge; and wherein the displayed second indicator and the displayed third indicator are both displayed on the scale when the vehicle is in the second driving mode.

2. The system of claim 1, further comprising: a display arranged to display the scale of state of charge of the battery and the state of charge detected, wherein the controller is arranged to control the display to display the scale in dependence on the state of charge detected.

3. The system of claim 2, wherein said display comprises the first indicator, the second indicator higher than the first indicator and a progressively increasing range of indication therebetween, and wherein said display comprises an extension to said range, said extension being represented differently to said range.

4. The system of claim 3, further comprising the third indicator higher than said second indicator, said extension being between said second and third indicators.

5. The system of claim 4, wherein said first indicator corresponds to the minimum parameter, wherein the controller is arranged to select the minimum parameter, wherein said second indicator corresponds to the maximum parameter, and said third indicator corresponds to an extended maximum parameter.

6. The system of claim 3, wherein said extension is enabled in a pre-determined charge condition.

7. The system of claim 6, wherein said extension is visible only in said pre-determined charge condition.

8. The system of claim 3, wherein said range comprises a first linear scale, and said extension comprises a second linear scale.

9. The system of claim 8, wherein said first linear scale comprises a sequence of marks at a first frequency, and wherein said second linear scale comprises a sequence of marks at a second frequency.

10. The system of claim 9, wherein the second frequency is at least twice that of the first frequency.

11. The system of claim 8, wherein said first and second linear scales comprise a single arc, and wherein the display comprises the marker, the marker being centred on said arc.

12. The system of claim 3, further comprising an instrument having a face, markings on said face to indicate said range and said extension, and the marker movable along said range and said extension to progressively indicate the state of charge.

13. A hybrid electric vehicle having a system according to claim 2, said vehicle including selectable driving modes of hybrid use, and being adapted to provide on said display a range of indication determined by the selected driving mode.

14. The vehicle of claim 13, further comprising selectable driving modes adapted to optimize one of fuel economy, distance in electric mode, and vehicle acceleration.

15. The system of claim 1, wherein the maximum parameter is associated with a maximum permitted charge, different from a current value of charge.

16. The system of claim 1, wherein the controller is arranged to change displaying the marker between the displayed first indicator and the displayed second indicator and between the displayed first indicator and the displayed third indicator in dependence upon a change in selection by a vehicle driver of the first driving mode or the second driving mode.

17. The system of claim 1, wherein controlling the marker to appear between the displayed first indicator and the displayed third indicator instead of between the displayed first indicator and the displayed second indicator is additionally dependent on at least one of: a state of charge of the vehicle battery, and a state of health of the vehicle battery.

18. A system for providing a scale of electrical charge of a vehicle battery, the system comprising: a displayed scale of state of charge of the vehicle battery, the displayed scale comprising a minimum parameter and a maximum parameter; and a controller arranged to select a value for the maximum parameter and/or a value for the minimum parameter of the displayed scale in dependence on a battery usage parameter, wherein the battery usage parameter is dependent on at least a mode of operation of the vehicle, selected from a plurality of driving modes of the vehicle; wherein the controller is arranged to select a first value for the maximum parameter and/or a first value for the minimum parameter of the displayed scale when a first driving mode is selected as the mode of operation of the vehicle, wherein the first value for the maximum parameter and the first value for the minimum parameter define a first range of state of charge values in the displayed scale, wherein the first range of state of charge values in the displayed scale indicate all possible state of charge values available while the first driving mode is selected as the mode of operation of the vehicle; wherein the controller is arranged to select a second value for the maximum parameter and/or a second value for the minimum parameter of the displayed scale when a second driving mode is selected as the mode of operation of the vehicle, wherein the second value for the maximum parameter and the second value for the minimum parameter define a second range of state of charge values in the displayed scale, wherein the second range of state of charge values in the displayed scale indicate all possible state of charge values available while the second driving mode is selected as the mode of operation of the vehicle; and wherein the second value for the maximum parameter represents a higher state of charge value than the first value for the maximum parameter, wherein the first value for the maximum parameter and the second value for the maximum parameter define an extension range of state of charge values in the displayed scale, wherein the state of charge values within the extension range represent possible state of charge values while the second driving mode is selected as the mode of operation of the vehicle that are not possible state of charge values while the first driving mode is selected as the mode of operation of the vehicle.

19. The system of claim 18, wherein the first value for the minimum parameter and the second value for the minimum parameter are the same state of charge value.

20. A system for providing a scale of electrical charge of a vehicle battery, the system comprising: a scale of state of charge of the vehicle battery, the scale comprising minimum and maximum parameters; a controller arranged to select the maximum and/or minimum parameters of the scale in dependence on a battery usage parameter, wherein the battery usage parameter is dependent on at least a mode of operation of the vehicle, selected from a plurality of driving modes of the vehicle; a state of charge detector arranged to detect a state of charge of the vehicle battery; and a display arranged to display the scale of state of charge of the battery and the detected state of charge of the battery, wherein the controller is arranged to control the display to display the scale in dependence on the detected state of charge of the battery; wherein said display comprises a first indicator, a second indicator higher than the first indicator and a progressively increasing range of indication therebetween, and wherein said display comprises an extension to said range, said extension being represented differently to said range; wherein said range comprises a first linear scale, and said extension comprises a second linear scale; and wherein said first linear scale comprises a sequence of marks at a first frequency, and wherein said second linear scale comprises a sequence of marks at a second frequency.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Other features of aspects of the invention will be apparent from the following description of embodiments illustrated by way of example only in the accompanying drawings in which:

(2) FIG. 1 represents an embodiment of a display according to aspects of the invention.

(3) FIGS. 2 and 3 represent an alternative embodiment according to aspects of the invention.

DESCRIPTION OF EMBODIMENTS

(4) With reference to the drawings a state of charge indicator or display 10 of a hybrid electric vehicle comprises a conventional circular dashboard dial having an arcuate scale 11 and a pointer 12 which can swing across the scale, as indicated by arrow 13, from a minimum to a maximum. The scale and the pointer may each be real or virtual.

(5) The arcuate scale 11 comprises a first portion with widely spaced graduations, and a second portion with closely spaced graduations.

(6) In the example illustrated the minimum 14 is represented by the left hand end of the scale, and the maximum 15 by the right hand end of the first scale portion. The second scale portion represents an extension to the charge range, and terminates at an extended maximum 16 at the extreme right hand end of the scale.

(7) The minimum 14 and maximum 15 may be for example marked MIN and MAX, and correspond to the nominal range of charge selected by a charge control program. The range may represent, for example, 30-50% of the theoretical maximum charge of for example a hybrid vehicle battery, and be optimised for overall fuel economy of the vehicle.

(8) Adjustment of the minimum 14 and/or maximum 15 and/or provision of the extension is performed by a controller (not shown). The controller determines the charge control program, or battery usage parameter, dependent on at least one of: a mode of operation of the vehicle; a state of charge of the battery; and a state of health of the battery.

(9) The extension represents an allowance, typically for opportunistic recharging, which permits the state of charge to reach for example 70% of the theoretical maximum charge, for example for optimising for city driving under electric power only. For example, city driving mode may be selected.

(10) The vehicle driver will thus be aware that a maximum nominal charge is reachable in normal use, and will not be concerned that the vehicle battery is faulty or that a charging fault has developed. The extension to the charge range represents an extended charge which is available in certain conditions of use associated with an action by the vehicle driver.

(11) The means by which the extension is distinguished from the normal range requires that a difference be noticeable. The difference may include a colour difference, and the colour of the extension may for example be blue, which is a colour that has become associated in the popular mind with electric vehicles or electrical vehicle travel.

(12) The indicator may be electronically generated, or may be a conventional instrument, or may be a combination.

(13) In one embodiment the extension may be visible only if the state of charge exceeds normal maximum 15, and in a variant the amount of extension which is visible may correspond to the state of charge that has been reached.

(14) In an embodiment the extension is visible only when certain vehicle programmes are activated. For example a vehicle driver may prepare for an extended period of driving in an electric mode by activating an E program. In such circumstances the extension may be made visible, and the engine may be commanded to charge the battery so as to increase the available range under electric drive only, to the extent permitted by the torque control system. In the example given above, the nominal state of charge of the battery will be increased from 50% to 70%, and the vehicle driver will be aware of the increased charge by virtue of the pointer 12 entering the extended range.

(15) Likewise the vehicle driver may require a period of rapid acceleration in a sport mode, and activate an S program in which both the engine and electric motor fully contribute to accelerating the vehicle. In consequence a greater reservoir of charge may be required, and accordingly when the driver is not commanding significant torque, the engine will be used to both drive the vehicle and to charge the battery to the extension limit of 70%. Such charging is opportunistic in the sense that should the vehicle driver command significant torque from the vehicle engine, charging of the battery in this mode will be suspended.

(16) It will be understood that the foregoing example quotes exemplar charging limits and ranges, which may of course be varied according to vehicle and conditions of use. In particular different levels for optimum charge and charge extension may be determined according to mode of vehicle use.

(17) An example of a change between scales is illustrated in FIGS. 2 and 3. The linear scale 21 of FIG. 2 has minimum and maximum markings 22, 23 and progressive markings therebetween indicating 25%, 50% and 75% of nominal charge capacity range (which may represent a range 30-50% of the theoretical charge of the battery). An indicator 24 for the scale, indicates the current value of charge. In place of a pointer a progressive colour change, a series of lights or any other progressive indicator could be used.

(18) In FIG. 3, the MAX identifier is substituted by a high frequency banding 25, which corresponds to the charge extension of FIG. 1.

(19) In switching from the scale of FIG. 2 to that of FIG. 3, the position of the indicator 24 is not changed, but the scale is extended to show the possibility of an increased state of charge (for example up to 70% of the theoretical charge of the battery), for example in preparation for city or sport driving according to a preference of the vehicle driver.

(20) Upon cessation of conditions for the extended scale of FIG. 3, the display reverts to the scale of FIG. 2, and maximum charge may be indicated notwithstanding that the actual state of charge corresponds to a value within zone 25.

(21) Variations and improvements to the invention are possible within the scope of the claims appended hereto.

(22) Aspects of the invention will be apparent from the numbered paragraphs that follow:

(23) 1. A display for displaying an amount between a minimum and a maximum, said display comprising a scale indicating a progressive increase from minimum to maximum, and an indicator movable with respect to the scale for indicating the instant value on said scale, wherein the range of said scale is adapted to be changed without movement of said indicator.

(24) 2. A display according to aspect 1 for indicating progressively a state of electrical charge of a battery, said display having a first indicator, a second indicator higher than the first indicator and a progressively increasing range of indication therebetween, wherein an extension to said range is provided, said extension being represented differently to said range.

(25) 3. A display according to aspect 2 and comprising a third indicator higher than said second indicator, said extension being between said second and third indicators.

(26) 4. A display according to aspect 3 wherein said first indicator corresponds to a minimum, said second indicator corresponds to a maximum, and said third indicator corresponds to an extended maximum.

(27) 5. A display according to aspect 2 wherein said extension is enabled in a pre-determined charge condition.

(28) 6. A display according to aspect 5 wherein said extension is visible only in said pre-determined charge condition.

(29) 7. A display according to aspect 2 wherein said extension is coloured differently to said range.

(30) 8. A display according to aspect 2 wherein said range comprises a first linear scale, and said extension comprises a second linear scale.

(31) 9. A display according to aspect 8 wherein said first linear scale comprises a sequence of marks at a first frequency, and wherein said second linear scale comprises a sequence of marks at a second frequency.

(32) 10. A display according to aspect 9 wherein the second frequency is at least twice that of the first frequency.

(33) 11. A display according to aspect 8 wherein said first and second linear scales comprise a single arc, and wherein an indicator needle is centred on said arc.

(34) 12. A display according to aspect 2, and comprising an instrument having a face, markings on said face to indicate said range and said extension, and an indicator needle movable along said range and said extension to progressively indicate a state of charge.

(35) 13. A hybrid electric vehicle having a display according to aspect 1, said vehicle including driver selectable modes of hybrid use, and being adapted to provide on said display a range of indication determined by the selected mode.

(36) 14. A vehicle according to aspect 13 and having driver selectable modes adapted to optimise one of fuel economy, distance in electric mode, and vehicle acceleration.

(37) 15. A method of displaying an amount between a minimum and a maximum by providing a scale, and an indicator for indicating on said scale an instant value of said amount, said method comprising: providing a plurality of said scales for display one by one with said indicator, and switching between scales whilst maintaining the instant position of said indicator.

(38) 16. A method according to aspect 15 and comprising displaying a state of charge of a battery of a hybrid electric vehicle, the method comprising: selecting a mode of vehicle operation from optimised fuel economy, optimised distance under solely electric power and optimised vehicle acceleration, and displaying a scale having a maximum appropriate to the selected mode.

(39) 17. A method according to aspect 16 and comprising displaying a nominal scale in a first mode of operation, and displaying an extension to said nominal scale in a second mode of operation.

(40) 18. A method according to aspect 17 wherein said nominal scale is between a minimum and a maximum, and said extension is above said maximum.

(41) 19. A method according to aspect 18 wherein said extension is provided in a mode corresponding to maximum distance under electric power, or in a mode corresponding to maximum performance.

(42) 20. A method according to aspect 17 wherein said extension is displayed differently to said nominal scale.