Abstract:
Provided is a display device of an electric vehicle that enables an occupant of an electric vehicle to more easily realize an effect of regeneration of braking energy. This display device of the electric vehicle calculates integrated cumulative value of the actual driving distance of the electric vehicle as a first distance, calculates, upon detecting regeneration of braking energy, integrated cumulative value of a drivable distance extended by the regeneration of the braking energy as a second distance, and displays both the first distance and the second distance on a display section.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a display device for an electric vehicle (display device of an electric vehicle) which is propelled by supplying electric power from an electric storage device to a first electric motor, converts deceleration energy of the electric vehicle into electric power with the first electric motor or a second electric motor, and stores the electric power as regenerated electric energy in the electric storage device. 
       BACKGROUND ART 
       [0002]    There has been proposed a device for indicating an amount of deceleration energy generated when a vehicle is decelerated, i.e., an amount of regenerated energy, to the driver of the vehicle {Japanese Laid-Open Patent Publication No. 2009-038895 (hereinafter referred to as “JP2009-038895A”)}. JP2009-038895A has an object to provide an amount-of-regenerated-energy indicating device for allowing the driver of a hybrid vehicle to recognize how much regenerated energy has been produced by the way the driver drives the hybrid vehicle and how much the driver has contributed to energy-saving driving of the vehicle (Abstract, [0006]). To achieve the above object, a hybrid control apparatus  15  according to JP2009-038895A integrates an amount of generated electric energy detected by an amount-of-generated-electric-energy detector  43  until the distance that a vehicle  1  has traveled reaches a predetermined distance, and divides the integrated amount of generated electric energy by the predetermined distance, thereby calculating a section amount of charged electric energy. A display device  19  displays on its screen the section amount of charged electric energy calculated by the hybrid control apparatus  15  (Abstract). The display device  19  displays the section amount of charged electric energy at all times if the section amount of charged electric energy can be calculated (see  FIG. 2 ). 
         [0003]    There is a technology for scoring an accelerating operation of the driver of a vehicle, a braking operation of the driver, and an engine idling operation performed by the driver, and displaying the scores as driving evaluations (U.S. Patent Application Publication No. 2011/0205044 (hereinafter referred to as “US2011/0205044A1”). 
       SUMMARY OF INVENTION 
       [0004]    According to JP2009-038895A, as described above, the display device displays on its screen a section amount of generated electric energy calculated by dividing an integrated amount of electric energy that has been regenerated, by a predetermined distance. However, even though the section amount of generated electric energy is displayed, the user may possibly find it difficult to understand a specific effect achieved by the displayed section amount of generated electric energy. According to JP2009-038895A, the display device displays the section amount of charged electric energy at all times if the section amount of charged electric energy can be calculated. Consequently, much remains to be improved with respect to the effective display timing for the user. 
         [0005]    The present invention has been made in view of the above drawbacks. It is an object of the present invention to provide a display device for an electric vehicle which allows the occupant of the electric vehicle to easily realize an effect of regeneration of electric energy from decelerating energy of the electric vehicle. 
         [0006]    According to the present invention, there is provided a display device for an electric vehicle which is propelled by supplying electric power from an electric storage device to a first electric motor, converts deceleration energy of the electric vehicle into electric power with the first electric motor or a second electric motor, and stores the electric power as regenerated electric energy in the electric storage device, the display device being configured to calculate an integrated value of an actual traveled distance of the electric vehicle as a first distance, detect that the deceleration energy is regenerated, calculate an integrated value of a traveling range which is increased by regeneration of the deceleration energy, as a second distance, and display the first distance and the second distance on one display unit. 
         [0007]    According to the present invention, the integrated value of the actual traveled distance of the electric vehicle is displayed as the first distance on the display unit, and the integrated value of the traveling range which is increased by regeneration of the deceleration energy is displayed as the second distance on the display unit. Consequently, the regenerated deceleration energy (regenerated energy) can be converted into the integrated value of the traveling range for easy comparison with the integrated value of the actual traveled distance of the electric vehicle, thus allowing an occupant of the electric vehicle to appreciate how effective the regenerated deceleration energy is. 
         [0008]    The display device may be configured to judge whether the second distance is to be displayed or not based on a predetermined display condition, and display the second distance only if the predetermined display condition is satisfied. Therefore, the integrated value of the traveling range that corresponds to the regenerated deceleration energy can be displayed in a situation that is appropriate for the occupant. 
         [0009]    The display device may be configured to judge whether an accelerating or decelerating operation by the driver of the electric vehicle is an operation to increase the traveling range or not, and display the judgment as a driving evaluation, switch from the displaying of the driving evaluation to the displaying of the second distance, and display the second distance in the same position as the position where the driving evaluation is displayed. Since the driving evaluation and the integrated value of the traveling range on regenerated deceleration energy are displayed in the same position, the occupant finds it easy to associate the driving evaluation with the integrated value of the traveling range which corresponds to the regenerated deceleration energy, and hence can look at the driving evaluation more objectively. 
         [0010]    The predetermined display condition may be a timing when the electric vehicle is stopped after the deceleration energy is regenerated while the electric vehicle is travelling downhill. Generally, when the deceleration energy is regenerated while the electric vehicle is travelling downhill, it is possible to regenerate a relatively large amount of deceleration energy, and the traveling range corresponding to the regenerated amount of deceleration energy is increased. Consequently, the occupant who sees the integrated value of the traveling range is able to recognize how important the regeneration of the deceleration energy is. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is a block diagram showing the general overall arrangement of an electric vehicle incorporating a display device according to an embodiment of the present invention; 
           [0012]      FIG. 2  is a flowchart of a processing sequence in relation to a traveling range that the electric vehicle can travel on regenerated energy; 
           [0013]      FIG. 3  is a diagram showing by way of example the relationship between vehicle speed, actual traveled distance (integrated value), and traveling range (integrated value) on regenerated energy; 
           [0014]      FIG. 4  is a diagram of a first example showing the manner in which a screen for not displaying a traveling range on regenerated energy and a screen for displaying the traveling range are switched; 
           [0015]      FIG. 5  is a diagram of a second example showing the manner in which a screen for not displaying a traveling range on regenerated energy and a screen for displaying the traveling range are switched; 
           [0016]      FIG. 6  is a diagram of a third example showing the manner in which a screen for not displaying a traveling range on regenerated energy and a screen for displaying the traveling range are switched; and 
           [0017]      FIG. 7  is a diagram of a fourth example showing the manner in which a screen for not displaying a traveling range on regenerated energy and a screen for displaying the traveling range are switched. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     A. Embodiment 
     1. Description of Overall Arrangement 
     [1-1. Overall Arrangement] 
       [0018]      FIG. 1  is a block diagram showing the general overall arrangement of an electric vehicle  10  (hereinafter referred to as “vehicle  10 ”) incorporating a display device  22  according to an embodiment of the present invention. As shown in  FIG. 1 , the vehicle  10  includes, in addition to the display device  22 , a drive force generating system  12 , an electric power supplying system  14 , a wheel rotational speed sensor  16 , a vehicle speed sensor  18 , an external air temperature sensor  20 , and a unified electronic control unit  24  (hereinafter referred to as “unified ECU  24 ”). 
         [0019]    The drive force generating system  12  has a motor (first electric motor), an inverter  32 , and a motor electronic control unit  34  (hereinafter referred to as “motor ECU  34 ”). The electric power supplying system  14  has a high-voltage battery  40  (hereinafter referred to as “battery  40 ”), a voltage sensor  42 , a current sensor  44 , a charging circuit  46 , a charging connector  48 , and a battery electronic control unit  50  (hereinafter referred to as “battery ECU  50 ”). 
       [1-2. Drive Force Generating System  12 ] 
       [0020]    The motor  30  comprises a three-phase AC brushless motor. The motor  30  generates a drive force F [N] (or torque [N·m]) for the vehicle  10  based on electric power supplied from the battery  40  through the inverter  32 . The motor  30  also supplies, to the battery  40 , electric power (hereinafter referred to as “regenerated electric power Preg”) [W] regenerated by recovering deceleration energy as regenerated energy, thereby charging the battery  40 . The motor  30  may supply the regenerated electric power Preg to an unillustrated 12-volt system or unillustrated auxiliaries. 
         [0021]    The inverter  32 , which is of three-phase bridge configuration, converts direct current into alternating current. The inverter  32  converts DC electric power into three-phase AC electric power and supplies the three-phase AC electric power to the motor  30 . The inverter  32  also converts AC three-phase electric power that is regenerated, into DC electric power and supplies the DC electric power to the battery  40 . 
         [0022]    The motor  30  and the inverter  32  operate while the vehicle  10  is running in both power and regenerative modes. It is assumed that the vehicle  10  runs in the power and regenerative modes unless otherwise specified. 
         [0023]    The motor ECU  34  controls the inverter  32  thereby to control output power (propulsive power) of the motor  30  based on commands from the unified ECU  24  and output signals from various sensors including the voltage sensor  42  and the current sensor  44 . 
       [1-3. Electric Power Supplying System  14 ] 
       [0024]    The battery  40 , which serves as an electric storage device (energy storage device) including a plurality of battery cells, may comprise a lithium ion secondary battery, a nickel hydrogen secondary battery, a capacitor, or the like. According to the present embodiment, the battery  40  comprises a lithium ion secondary battery. 
         [0025]    The voltage sensor  42  detects a voltage across the battery  40  (hereinafter referred to as “battery voltage Vbat”), and supplies the detected battery voltage Vbat to the battery ECU  50 . The current sensor  44  detects an output current flowing from the battery  40  and an input current flowing to the battery  40  (both currents will hereinafter be referred to as “battery current Ibat”), and supplies the detected battery current Ibat to the battery ECU  50 . 
         [0026]    The charging circuit  46  and the charging connect- or  48  are used in charging the battery  40  from an external charging device, not shown. The charging circuit  46  includes circuit parts such as a charger, not shown, etc. The charging connector  48  is used to connect the charging circuit  46  to the external charging device. 
         [0027]    The battery ECU  50  is used to manage the battery  40 , e.g., to control the opening and closing of a contactor, not shown, while monitoring the battery voltage Vbat and the battery current Ibat, etc. 
         [0000]    [1-4. Wheel Rotational Speed Sensor  16 , Vehicle Speed sensor  18 , external air temperature sensor  20 ] 
         [0028]    The wheel rotational speed sensor  16  detects the number of revolutions of a wheel, not shown (hereinafter referred to as “wheel rotational speed Nw”) [rev], and outputs the detected wheel rotational speed Nw to the display device  22 , the unified ECU  24 , etc. via a communication line  52 . The vehicle speed sensor  18  detects the vehicle speed V [km/h] of the vehicle  10  and outputs the detected vehicle speed V to the display device  22 , the unified ECU  24 , etc. via the communication line  52 . The vehicle speed sensor  18  detects the vehicle speed V based on the wheel rotational speed Nw from the wheel rotational speed sensor  16 , for example. The external air temperature sensor  20  detects the external air temperature (hereinafter referred to as “external air temperature Tex”) [° C.] around the vehicle  10 , and outputs the detected external air temperature Tex to the display device  22 , the unified ECU  24 , etc. via the communication line  52 . 
       [1-5. Display Device  22 ] 
     (1-5-1. Overall Arrangement) 
       [0029]    The display device  22  presents information about the vehicle  10  to the user. As shown in  FIG. 1 , the display device  22  has a display electronic control unit  60  (hereinafter referred to as “display ECU  60 ”), an operating unit  62 , a display unit  64 , and a speaker  66 . 
       (1-5-2. Display ECU  60 ) 
       [0030]    The display ECU  60  displays various items of information based on output signals from the wheel rotational speed sensor  16 , the vehicle speed sensor  18 , and the external air temperature sensor  20 . As shown in  FIG. 1 , the display ECU  60  has an input/output unit  70 , a processor  72 , and a memory  74 . The input/output unit  70  is used to exchange signals with various components. The processor  72 , which performs various processing operations, includes a traveled distance calculating function  80 , a regenerated energy calculating function  82 , a traveling range calculating function  84  (hereinafter referred to as “Dreg calculating function  84 ”), a traveling range displaying function  86  (hereinafter referred to as “Dreg displaying function  86 ”), and a driving evaluating function  88 . 
         [0031]    The traveled distance calculating function  80  is a function to calculate an actual traveled distance D [km] (integrated value) of the vehicle  10  based on the wheel rotational speed Nw from the wheel rotational speed sensor  16 . Specifically, since the radius and circumference of the non-illustrated wheel are known, the actual traveled distance D of the vehicle  10  can be determined if the wheel rotational speed Nw is known. The actual traveled distance D of the vehicle  10  may be determined based on the number of revolutions [rev] of the drive shaft, not shown, of the vehicle  10 , instead of the wheel rotational speed Nw. Alternatively, the actual traveled distance D of the vehicle  10  may be determined by determining the present position of the vehicle  10  from time to time by a navigation system, not shown. 
         [0032]    The regenerated energy calculating function  82  calculates an amount of deceleration energy (regenerated energy) [Wh] (instantaneous value) regenerated per unit time when the vehicle  10  is decelerated (hereinafter referred to as “amount Ereg of regenerated energy”), as described in detail later. 
         [0033]    The traveling range calculating function  84  calculates a range [km] (integrated value) that the vehicle  10  can travel on the amount Ereg of regenerated energy based on the amount Ereg of regenerated energy calculated by the regenerated energy calculating function  82  (hereinafter referred to as “traveling range Dreg”), as described in detail later. 
         [0034]    The traveling range displaying function  86  judges whether the traveling range Dreg calculated by the Dreg calculating function  84  is to be displayed or not, and, if the traveling range Dreg is to be displayed, displays the traveling range Dreg according to a predetermined process, as described in detail later. 
         [0035]    The driving evaluating function  88  is a function to judge whether an accelerating or decelerating operation by the driver is an operation to increase the traveling range Dreg or not, and displays the judgment as a driving evaluation. The driving evaluating function  88  may have its processing sequence performed according to US2011/0205044A1, for example. 
         [0036]    According to US2011/0205044A1, an accelerating operation of the driver, a braking operation of the driver, and an engine idling operation performed by the driver are scored (see, for example, FIG. 11 of US2011/0205044A1). Based on the overall points obtained from the scored operations and driving operation, a score display area  35  of a second display unit  15  (see FIG. 2( b ) of US2011/0205044A1) displays a score (point) that represents the way the driver drives the vehicle, as evaluated from the standpoint of fuel economy ([0054] of US2011/0205044A1). More specifically, a display configuration which is capable of displaying five leaves, displays the leaves such that the more the displayed leaves, the higher the score, thereby indicating that the driver is driving the vehicle for better fuel economy (see the same paragraph). According to US2011/0205044A1, furthermore, the second display unit  15  has a coaching display area  37  (see FIG. 2( b ) of US2011/0205044A1). The coaching display area  37  displays evaluations of the accelerating operation of the driver and the braking operation of the driver (see, for example, through [0065] of US2011/0205044A1). According to the present embodiment, the display device  22  can utilize the driving evaluating function, including the above displayed items of information, disclosed in US2011/0205044A1. 
         [0037]    The memory  74  ( FIG. 1 ) according to the present embodiment comprises a RAM (Random Access Memory) for storing temporary data, etc. for use in various processing operations carried out by the processor  72  and a ROM (Read Only Memory) storing programs to be executed, tables or maps, etc. 
       (1-5-3. Operating Unit  62 ) 
       [0038]    The operating unit  62  includes a display switching switch  90  (hereinafter referred to as “display switching SW  90 ”) and a traveling range resetting switch  92  (hereinafter referred to as “Dreg resetting SW  92 ” or “resetting SW  92 ”). The display switching SW  90  is used to switch between displayed information on the display unit  64 . The Dreg resetting SW  92  is used to reset the traveling range Dreg that the vehicle  10  can travel on regenerated energy. 
       (1-5-4. Display Unit  64  and Speaker  66 ) 
       [0039]    The display unit  64 , which is capable of displaying color images or monochromatic images, comprises a liquid crystal panel, an organic EL (Electro-Luminescence) panel, or an inorganic EL panel, for example. The speaker outputs sounds such as sound effects to be described later. 
       [1-6. Unified ECU  24 ] 
       [0040]    The unified ECU  24  manages the vehicle  10  in its entirety. According to the present embodiment, the unified ECU  24  controls, for example, the wheel rotational speed sensor  16 , the vehicle speed sensor  18 , the external air temperature sensor  20 , the motor ECU  34 , the battery ECU  50 , and the display ECU  60  via the communication line  52  (signal line). To the unified ECU  24 , a signal from a start switch  100  (hereinafter referred to as “start SW  100 ”) is input. 
       2. Processing Related to the Traveling Range Dreg on Regenerated Energy 
       [0041]    According to the present embodiment, as described above, a traveling range Dreg that the vehicle  10  can travel on regenerated energy can be calculated and displayed. 
         [0042]      FIG. 2  is a flowchart of a processing sequence in relation to the traveling range Dreg on regenerated energy. The flowchart shown in  FIG. 2  represents the processing sequence concerning the traveling range Dreg on regenerated energy. It is noted that the processing sequence is performed separately from other processing sequences carried out by the display ECU  60 , e.g., a processing sequence of the traveled distance calculating function  80  for calculating an actual traveled distance D and a processing sequence of the driving evaluating function  88  for evaluating the way the driver drives the vehicle  10 . A value calculated in a present processing cycle (from S 2  through S 8  in  FIG. 2 ) will hereinafter be accompanied by “(present)”, and a value calculated in a previous processing cycle by “(previous)”, whereby they are discriminated from each other. 
         [0043]    In step S 1 , it is judged whether the display device  22  is activated or not. Specifically, if the start SW  100  is off, then the unified ECU  24  does not permit a 12-V battery, not shown, to supply electric power to the display device  22 , and hence the display device  22  is not activated. If the start SW  100  is on, then the unified ECU  24  permits the 12-V battery to supply electric power to the display device  22 , so that the display device  22  is activated. If the display device  22  is not activated (S 1 : NO), then control repeats step S 1 . If the display device  22  is activated (S 1 : YES), then control goes to step S 2 . 
         [0044]    In step S 2 , the display ECU  60  (regenerated energy calculating function  82 ) judges whether the vehicle  10  is in the regenerative mode or not. For example, if the battery current Ibat detected by the current sensor  44  flows from the inverter  32  to the battery  40 , then the display ECU  60  judges that the vehicle  10  is in the regenerative mode. However, as described later, the regenerative mode may be judged according to another process. 
         [0045]    If the vehicle  10  is not in the regenerative mode (S 2 : NO), then control jumps to step S 6 . If the vehicle  10  is in the regenerative mode (S 2 : YES), then in step S 3 , the display ECU  60  (regenerated energy calculating function  82 ) calculates an amount Ereg of regenerated energy as an amount of deceleration energy (regenerated energy) regenerated in the present processing cycle. The display ECU  60  (regenerated energy calculating function  82 ) calculates an amount Ereg of regenerated energy using the battery voltage Vbat and the battery current Ibat, for example. Specifically, the display ECU  60  (regenerated energy calculating function  82 ) calculates an amount Ereg of regenerated energy by integrating a current (battery current Ibat) flowing into the battery  40  per unit time in the regenerative mode and a battery voltage Vbat across the battery  40  at that time. 
         [0046]    In step S 4 , the display ECU  60  (Dreg calculating function  84 ) calculates an additive range value ΔDreg [km] in the present processing cycle. The additive range value ΔDreg represents a traveling range that the vehicle  10  can travel on the amount Ereg of regenerated energy, i.e., an amount per unit time, calculated in the present processing cycle. For example, the additive range value ΔDreg is calculated as follows: The actual traveled distance D up to that time (integrated value) is divided by an amount of consumed electric power corresponding thereto, and the quotient is determined as a traveling range per unit amount of electric power (hereinafter referred to as “unit traveling range”). Then, a value calculated by multiplying the unit traveling range by the amount Ereg of regenerated energy is used as the traveling range Dreg (ΔDreg=the unit traveling range×Ereg). 
         [0047]    In step S 5 , the display ECU  60  calculates a traveling range Dreg (present) on the regenerated energy produced by the vehicle  10 . The traveling range Dreg (present) in the present processing cycle is calculated as the sum of the traveling range Dreg (previous) in the previous processing cycle and the additive range value ΔDreg (present) determined in step S 4  {Dreg (present)=Dreg (previous)+ΔDreg (present)}. 
         [0048]      FIG. 3  shows by way of example the relationship between vehicle speed V, actual traveled distance D (integrated value), and traveling range Dreg (integrated value) on regenerated energy. In  FIG. 3 , the vehicle  10  travels on a relatively flat road from 0 to D 1  and from D 3  to D 4  in the actual traveled distance D, and travels on a relatively steep upslope from D 1  to D 2  in the actual traveled distance D. Consequently, almost no regenerated energy is produced, and the traveling range Dreg hardly increases at all. 
         [0049]    From D 2  to D 3  in the actual traveled distance D, the vehicle  10  travels on a relatively steep downslope. Consequently, relatively large regenerated energy is produced, and the traveling range Dreg significantly increases. The vehicle  10  travels on an expressway from D 4  to D 5  in the actual traveled distance D. Therefore, almost no regenerated energy is produced, and the traveling range Dreg hardly increases at all. 
         [0050]    Referring back to  FIG. 2 , if the vehicle  10  is not in the regenerative mode (S 2 : NO) or after step S 5 , the display ECU  60  (Dreg calculating function  84 ) judges whether the traveling range Dreg (present) is to be reset or not in step S 6 . Specifically, the display ECU  60  (Dreg calculating function  84 ) judges whether the Dreg resetting SW  92  of the operating unit  62  is pressed or not. Alternatively, as described later, the display ECU  60  (Dreg calculating function  84 ) may judge whether the traveling range Dreg (present) is to be reset or not based on other conditions. 
         [0051]    If the traveling range Dreg (present) is not to be reset (S 6 : NO), then control goes to step S 8 . If the traveling range Dreg (present) is to be reset (S 6 : YES), then the display ECU  60  (Dreg calculating function  84 ) resets the traveling range Dreg (present) in step S 7 . Stated otherwise, the display ECU  60  (Dreg calculating function  84 ) sets the traveling range Dreg (present) in the present processing cycle to 0. 
         [0052]    In step S 8 , the display ECU  60  (Dreg displaying function  86 ) judges whether a display condition for displaying the traveling range Dreg is satisfied or not. The display condition is a condition to be satisfied in order to display the traveling range Dreg (present) on the display unit  64 . 
         [0053]    According to the present embodiment, the display condition may be a certain timing such as when an integrated value of the amount Ereg of regenerated energy or an increase in the traveling range Dreg during a predetermined period exceeds a predetermined threshold value (hereinafter referred to as “increase threshold value”), when the regenerative mode continues for a predetermined time (hereinafter referred to as “regenerative mode judging time”), when the vehicle  10  is stopped, when the vehicle  10  is stopped after being braked, at a time immediately after the start SW  100  is turned off, when the vehicle  10  is travelling downhill, when the vehicle  10  is stopped after the regenerative mode while the vehicle  10  is travelling downhill, or when the display switching SW  90  is operated, for example. The traveling range Dreg may be displayed at all times. 
         [0054]    If the display condition is not satisfied (S 8 : NO), then control goes to step S 10 . If the display condition is satisfied (S 8 : YES), then the display ECU  60  (Dreg displaying function  86 ) displays the traveling range Dreg (present) depending on the display condition in step S 9 . 
         [0055]      FIGS. 4 through 7  show first through fourth examples showing the manner in which a screen for not displaying the traveling range Dreg on regenerated energy and a screen for displaying the traveling range Dreg are switched.  FIG. 4  shows by way of example the manner in which a screen  110  on the display unit  64  that does not display any information including the traveling range Dreg is switched to a screen  112  that displays the traveling range Dreg. On the screen  112 , the letters “REGENE” are an abbreviation of “regeneration”, and indicate the display of the traveling range Dreg (the same applies to  FIGS. 5 through 7 ). “+10 km” on the screen  112  represents the displayed value of the traveling range Dreg. 
         [0056]      FIG. 5  shows by way of example the manner in which a screen  114  that displays information excluding the traveling range Dreg is switched to a screen  116  that displays information including the traveling range Dreg. In  FIG. 5 , an area indicating a mark of leaves (hereinafter referred to as “score display area  130 ”) is an area for displaying a score (point) that corresponds to the evaluation of the way the driver drives the vehicle  10  from the standpoint of fuel economy. According to the present embodiment, the value of a score is represented by the number of “leaves”. A process of calculating the value of a score and a process of displaying the score display area  130  may utilize the processes disclosed in US2011/0205044A1 (see FIG. 2( b ), [0054], etc. of US2011/0205044A1). 
         [0057]    In  FIG. 5 , an area indicated by the reference numeral  132  (hereinafter referred to as “coaching display area  132 ”) serves to coach the driver on the proper way to use the acceleration and the brake. A process of displaying the coaching display area  132  may utilize the process disclosed in US2011/0205044A1 (see  FIG. 2(   b ), [0055] through [0065], etc. of US2011/0205044A1). 
         [0058]    In  FIG. 5 , the letter “B” on the screens  114 ,  116  indicates the display of the actual traveled distance D. According to the present embodiment, specifically, the actual traveled distance D can be displayed selectively in “A” and “B” (see  FIG. 6 ). On the screens  114 ,  116  shown in  FIG. 5 , “B” is selected. On the screens  114 ,  116  shown in  FIG. 5 , the characters “2345.6 km” indicate the actual traveled distance D at the time “B” is selected. Furthermore, the characters “30° C.” on the screen  114 ,  116  shown in  FIG. 5  represent the output value (external air temperature Tex) of the external air temperature sensor  20 . 
         [0059]    When the screen  114  is switched to the screen  116  as shown in  FIG. 5 , the area which has displayed the score display area  130  on the screen  114  displays “REGENE” and “+10 km” on the screen  116 , thereby displaying the traveling range Dreg. 
         [0060]      FIG. 6  shows by way of example the manner in which a screen  118  that displays the actual traveled distance D in “A” is switched to a screen  120  that displays the actual traveled distance D in “B”. On the screen  118 , “A” indicates that the actual traveled distance D is displayed in “A”, and “75 km” indicates the actual traveled distance D at the time “A” is selected. In addition, on the screen  118 , “REGENE” indicates the display of the traveling range Dreg, and “+10 km” indicates the value of the traveling range Dreg at the time “A” is selected. 
         [0061]    On the screen  120 , “B” indicates that the actual traveled distance D is displayed in “B”, and “15 km” indicates the actual traveled distance D at the time “B” is selected. In addition, on the screen  120 , “REGENE” indicates the display of the traveling range Dreg, and “+3 km” indicates the value of the traveling range Dreg at the time “B” is selected. 
         [0062]    As described above, the actual traveled distance D can be displayed selectively in two modes (hereinafter referred to as “trip modes”), making it possible to display actual traveled distances D from different points of time. The screens  118 ,  120  can be switched from one to the other by the user operating the display switching SW  90 . The points of time at which to start calculating actual traveled distances D in the two trip modes “A”, “B” may be set using a switch (for resetting the actual traveled distance D), not shown, included in the operating unit  62 , for example. 
         [0063]    In  FIG. 6 , the traveling range Dreg is displayed at all times. When the screens  118 ,  120  are switched from one to the other, the trip modes are also switched from one to the other, and the corresponding traveling ranges Dreg are also switched from one to the other. 
         [0064]      FIG. 7  shows by way of example the manner in which, while the traveling range Dreg on regenerated energy is being displayed at all times, a screen  122  for normal display is switched to a screen  124  for highlighted display, which is then switched back to a screen  126  for normal display. In  FIG. 7 , the traveling range Dreg is highlighted, i.e., displayed in a larger character size than normal, only when the traveling range Dreg takes a predetermined value, e.g., a round number in the present embodiment (“+10 km” in  FIG. 7 ). Alternatively, the traveling range Dreg may be highlighted when it falls within a predetermined range, rather than when it takes a predetermined value. The traveling range Dreg may be highlighted in other ways than being displayed in a larger character size than normal. For example, the traveling range Dreg may be highlighted by being displayed in a different color, or by being displayed at a higher brightness level, or by being displayed in combination with a character that is not displayed normally. Further alternatively, not only the traveling range Dreg is highlighted in display, but also a certain sound effect may be output by the speaker  66 . 
         [0065]    Referring back to  FIG. 2 , in step S 10 , it is judged whether the display device  22  is deactivated or not. Specifically, if the start SW  100  is on, then the unified ECU  24  permits the 12-V battery to continuously supply electric power to the display device  22 , and hence the display device  22  keeps activated. If the start SW  100  is off, then the unified ECU  24  controls the 12-V battery to stop supplying electric power to the display device  22 , so that the display device  22  is deactivated. If the display device  22  is not deactivated (S 10 : NO), then the present processing cycle is finished, and control goes back to step S 2  to start a next processing cycle. If the display device is deactivated (S 10 : YES), then the present processing cycle is finished, and the processing sequence shown in  FIG. 2  is ended. 
       3. Advantages of the Present Embodiment 
       [0066]    According to the present embodiment, as described above, the actual traveled distance D (integrated value) of the vehicle  10  is displayed on the display unit  64  (the screens  114 ,  116  shown in  FIG. 5  and the screens  118 ,  120  shown in  FIG. 6 ), and the traveling range Dreg (integrated value) which represents an extension of the traveling range increased by the regenerated deceleration energy is also displayed on the display unit  64  (the screen  112  shown in  FIG. 4 , the screen  116  shown in  FIG. 5 , the screens  118 ,  120  shown in  FIG. 6 , and the screens  122 ,  124 ,  126  shown in  FIG. 7 ). Consequently, the regenerated deceleration energy can be converted into the traveling range Dreg for easy comparison with the actual traveled distance D of the vehicle  10 , thus allowing the occupant of the vehicle  10  to easily appreciate how effective the regenerated deceleration energy is. 
         [0067]    According to the present embodiment, it is judged whether the traveling range Dreg on regenerated energy is to be displayed or not based on a certain display condition (S 8  in  FIG. 2 ), and only if the display condition is satisfied, the traveling range Dreg is displayed (S 9 ). Therefore, the traveling range Dreg that corresponds to the regenerated deceleration energy can be displayed in a situation that is appropriate for the driver. 
         [0068]    According to the present embodiment, it is judged whether an accelerating or decelerating operation by the driver is an operation to increase the traveling range Dreg or not, and the judgment is displayed as a driving evaluation (see the score display area  130  on the screen  114  shown in  FIG. 5 ). Then, the display in the score display area  130  is switched to the display of the traveling range Dreg, so that the traveling range Dreg on regenerated energy is displayed in the same position as the display position in the score display area  130  (see the screen  116  shown in  FIG. 5 ). Since the score display area  130  (driving evaluation) and the traveling range Dreg on regenerated energy are displayed in the same position, the occupant finds it easy to associate the driving evaluation in the score display area  130  with the traveling range Dreg, and hence can look at the driving evaluation more objectively. 
         [0069]    According to the present embodiment, the display condition referred to above may be set to a timing when the vehicle  10  is stopped after the regenerative mode while the vehicle  10  is travelling downhill. Generally, during the regenerative mode while the vehicle  10  is travelling downhill, it is possible to regenerate a relatively large amount of deceleration energy, and the traveling range Dreg corresponding to the regenerated amount of deceleration energy is increased. Consequently, the occupant who sees the traveling range Dreg is able to recognize how important the regenerative mode is. 
       B. Modifications 
       [0070]    The present invention is not limited to the above embodiment, but may employ various arrangements based on the disclosure of the above description. For example, the present invention may employ the following arrangements: 
         [0000]    1. Object that Incorporates the Display Device: 
         [0071]    In the above embodiment, the display device  22  is incorporated in the vehicle  10  which has the single motor  30  and the single battery  40 . However, it is not limited to being incorporated in such a vehicle, and the display device  22  may be incorporated in other objects. For example, the display device  22  may be incorporated in an electric vehicle having a propulsive motor and a regenerative motor separately. The display device  22  may also be incorporated in a hybrid vehicle having an engine in addition to the motor  30 , or a fuel cell vehicle having fuel cells in addition to the motor  30  and the battery  40 . The display device  22  may further be incorporated not only in the electric vehicle  10 , but also in mobile objects such as ships, aircrafts, bicycles, etc. 
       2. Motor  30 : 
       [0072]    In the above embodiment, the motor  30  comprises a three-phase AC brushless motor. However, the motor  30  is not limited to the above insofar as it can propel the vehicle  10 . For example, another motor such as a three-phase AC brush motor, a single-phase AC motor, or a DC motor may be used. 
       3. Judgment of the Regenerative Mode: 
       [0073]    In the above embodiment, it is judged whether the vehicle is in the regenerative mode or not based on the battery current Ibat detected by the current sensor  44  (S 2  in  FIG. 2 ). However, other values may be used insofar as they are effective to judge the regenerative mode. For example, the regenerative mode may be judged when the electric power supplied to the motor  30  is of a negative value or when the value of input and output electric power in the entire vehicle  10 , which includes the electric power consumed by an air compressor, auxiliaries, etc., not shown, is of a negative value. Alternatively, the regenerative mode may be judged when the vehicle  10  is judged as being decelerated based on at least one of the vehicle speed V from the vehicle speed sensor  18 , positional information from a navigation system, not shown, and an output value from a gyro sensor, not shown. Alternatively, the deceleration (regenerative mode) may be judged based on an operation quantity of an accelerator pedal or a brake pedal, not shown. 
       4. Resetting of the Traveling Range Dreg on Regenerated Energy: 
       [0074]    In the above embodiment, the traveling range Dreg is reset on the condition that the Dreg resetting SW  92  is turned on. However, the traveling range Dreg may be reset on other conditions. For example, the traveling range Dreg may be reset based on a user&#39;s operation, e.g., when the start SW  100  is turned off, when the battery  40  is charged through the charging circuit  46  and the charging connector  48 , or when the display switching SW  90  is operated to switch display screens (see  FIG. 6 , for example). Alternatively, the traveling range Dreg may be reset at a preset time, e.g., once a day or once a week. Further alternatively, the traveling range Dreg may be reset when the actual traveled distance D has reached a preset distance. The resetting conditions may be set, for example, using a switch, not shown, on the operating unit  62 , or the like. 
       5. Display on the Display Unit  64 : 
       [0075]    In the above embodiment, the display unit  64  displays the traveling range Dreg (integrated value) on regenerative energy. However, the display unit  64  may display the additive range value ΔDreg (instantaneous value) or a traveling range Dreg per unit time in addition to or instead of the traveling range Dreg (integrated value) on regenerative energy.