JP2024090375A - Driving area display system - Google Patents

Abstract

A system is provided that can display a drivable area with a focus on the vehicle's traveling direction.
[Solution] The vehicle includes an acquisition unit that acquires the drivable area in which the vehicle can travel with the vehicle's current remaining energy amount from a target range including the vehicle's direction of travel, which becomes narrower as the vehicle travels, and a display control unit that displays the acquired drivable area.
[Selected Figure] Figure 1

Description

The present invention relates to a driving area display system.

Conventionally, there are known devices that calculate a vehicle's cruising distance based on the remaining charge of the battery and display the calculated cruising distance. For example, Patent Document 1 discloses a navigation device that calculates a vehicle's cruising distance taking into account the deterioration state of the battery. Patent Document 2 discloses a display device that calculates the probability of reaching a position corresponding to the cruising distance as a reaching probability, and displays the vehicle's cruising distance and the reaching probability.

International Publication No. WO 2012/133670 JP 2022-007768 A

In the configurations of Patent Documents 1 and 2, when displaying the cruising distance from the vehicle's current position, the cruising distance in all directions (360° directions) from the vehicle's current position is displayed. However, since the vehicle's direction of travel is determined in a predetermined direction as the vehicle travels, there are cases where the driver prefers a display that focuses on the direction of travel rather than a display of the cruising distance in all directions (i.e., a drivable area that shows the drivable area).

The present invention was made in consideration of the above problems, and aims to provide a system that can display drivable areas focusing on the vehicle's traveling direction.

To achieve the above object, the driving area display system of the present invention includes an acquisition unit that acquires the driving area in which the vehicle can be driven with the current remaining energy amount from a target range including the traveling direction of the vehicle, which becomes narrower as the vehicle drives, and a display control unit that displays the acquired driving area.

In other words, in the driving area display system, the driving area in which the vehicle can travel with the current remaining energy amount is obtained from a target range including the traveling direction, which becomes narrower as the vehicle travels, and the obtained driving area is displayed on the display unit. As a result, the display unit always displays the driving area including the traveling direction in which the driver is traveling, and excludes areas other than the traveling direction as the vehicle travels. In other words, the driving area is displayed with a focus on the traveling direction. Therefore, for a driver who prefers a display that focuses on the traveling direction rather than a display of the driving area in the entire circumference of the vehicle, the annoyance of seeing the driving area other than the traveling direction can be reduced.

FIG. 1 is a block diagram showing an example of a travelable area display system. 2A and 2B are flowcharts showing an example of processing in this embodiment, in which FIG. 2A shows a travelable area display process, and FIG. 2B shows a subroutine in FIG. 2A. 13 is a display example of a drivable area. 4 is a display example of a drivable area when the vehicle travels from the display in FIG. 3 . 5A and 5B are flowcharts showing an example of processing in another embodiment (round trip mode), in which FIG. 5A shows a travelable area display processing, and FIG. 5B shows a subroutine in FIG. 5A. 13 is a display example of a drivable area in a round trip mode. 7 is a flowchart showing an example of processing in another embodiment (low load mode), in which FIG. 7A shows a travelable area display process, and FIG. 7B shows a subroutine in FIG. 7A. 13 is a display example of a travelable area in another embodiment.

Here, the embodiments of the present invention will be described in the following order.
(1) Configuration of driving area display system:
(2) Driving area display process:
(3) Other embodiments:

(1) Configuration of driving area display system:
FIG. 1 is a block diagram showing a configuration of a drivable area display system 10 mounted on a vehicle. The drivable area display system 10 is a system that displays a drivable area (travelable distance) that can be traveled with the current remaining energy amount of the vehicle on a display unit or the like of a user I/F unit 44. In this embodiment, the drivable area display system 10 is mounted on a vehicle and realized by a navigation system. The vehicle according to this embodiment is an electric vehicle (BEV: Battery Electric Vehicle) that is mounted with a battery 40 that is a rechargeable storage battery and is driven by supplying electric power stored in the battery 40 to a motor 50. That is, the drivable area display system 10 shown in FIG. 1 displays a drivable area that can be traveled with the current remaining charge amount of the battery 40 on a display unit of the user I/F unit 44.

The driving area display system 10 includes a control unit 20 including a CPU, RAM, ROM, etc., and a recording medium 30. The control unit 20 can execute a driving area display program 21 stored in the ROM, etc.

Map information 30a is recorded on the recording medium 30. The map information 30a indicates information on roads and the like that is referenced for route guidance and the like. In this embodiment, the map information 30a includes node data, link data, shape interpolation point data, and facility data. The node data is data indicating the position of an intersection. The link data indicates a road section and is associated with a node corresponding to an end point of the road section. In other words, the link data indicates a link that connects nodes. In this embodiment, the link data includes information indicating the road attributes of the road section indicated by the link data. The road attributes include information indicating the road type, for example, an expressway, a motorway, a general road such as a national road or a prefectural road, a narrow street, etc. In addition, shape interpolation point data indicating the position of a shape interpolation point for identifying the shape of the road between the nodes is associated with the link data. In addition, the link data includes information indicating the road gradient in the road section.

The facility data indicates the name, location, and attributes of facilities that exist around roads, etc. In this embodiment, facilities include various facilities that can be destinations. For example, the names, locations, attributes, etc. of rest areas such as service areas, stores, commercial facilities, public facilities, etc. are defined as facility data.

The vehicle in this embodiment includes a GNSS receiver 41, a vehicle speed sensor 42, a gyro sensor 43, a user I/F unit 44, a battery 40, a motor 50, and an ECU 60 that controls the vehicle.

The GNSS receiver 41 is a device that receives signals from the Global Navigation Satellite System. The GNSS receiver 41 receives radio waves from navigation satellites and outputs a signal for calculating the vehicle's position via an interface (not shown). The control unit 20 acquires this signal to acquire the vehicle's position. The vehicle speed sensor 42 outputs a signal corresponding to the rotational speed of the wheels of the vehicle. The control unit 20 acquires this signal via an interface (not shown) to acquire the vehicle speed.

The gyro sensor 43 detects the angular acceleration of the vehicle turning in a horizontal plane and outputs a signal corresponding to the orientation of the vehicle. The control unit 20 acquires this signal to obtain the traveling direction of the vehicle. The vehicle speed sensor 42 and the gyro sensor 43 are used to identify the traveling trajectory of the vehicle. In this embodiment, the control unit 20 identifies the position of the vehicle based on the departure point and traveling trajectory of the vehicle, and corrects the current position of the vehicle identified based on the departure point and traveling trajectory based on the output signal of the GNSS receiving unit 41. The control unit 20 also performs map matching processing based on the trajectory of the vehicle's position and the map information 30a to identify the position of the vehicle on the road.

The user I/F unit 44 is an interface unit for inputting user instructions and providing various information to the user, and includes a display unit consisting of a touch panel display (not shown), input units such as switches, and output units such as speakers. In this embodiment, the drivable area acquired by the control unit 20 is displayed on the display unit of the user I/F unit 44.

The battery 40 is a high-voltage power storage device, for example, a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery, or a capacitor. The battery 40 is electrically connected to the motor 50, which is the driving force source, and the vehicle is driven by supplying power from the battery 40 to the motor 50. A sensor (not shown) is attached to the battery 40, and the sensor outputs information indicating the remaining charge of the battery. Based on the output of the sensor, the control unit 20 periodically obtains the remaining charge of the battery 40 via the ECU 60.

The motor 50 is, for example, a permanent magnet synchronous motor or an induction motor, and is connected to the drive wheels of the vehicle (not shown) so as to be capable of transmitting power. The motor 50 functions as an electric motor that is driven by receiving at least electric power and outputs torque. The motor 50 also functions as a generator that generates electric power by receiving torque from the outside and being driven. That is, the motor 50 is a so-called motor generator that combines the functions of an electric motor and a generator. The motor 50 is electrically connected to the battery 40 as described above. Therefore, the electric power stored in the battery 40 can be supplied to the motor 50, and the motor 50 can function as an electric motor to output drive torque. The motor 50 can also function as a generator by the torque transmitted from the drive wheels, and the regenerative power generated at that time can be stored in the battery 40. The output speed and output torque of the motor 50 are electrically controlled by the ECU 60.

The ECU 60 is an electronic control device mainly composed of, for example, a microcomputer, and in the example shown in FIG. 1, it mainly controls the motor 50. Specifically, the ECU 60 can output a control signal to the motor 50, and by outputting a control signal to the motor 50, the motor 50 is operated to drive the vehicle. The motor 50 can also be rotated in the opposite direction to the direction of rotation when the vehicle is running, and the regenerative power generated by this rotation is charged to the battery 40. In other words, the control signal output by the ECU 60 controls the switching between charging and discharging by the motor 50, and the regenerative power is recovered.

The control unit 20 can execute a program stored in the recording medium 30 or ROM. In this embodiment, the program can be a drivable area display program 21. Conventionally, a method for displaying a drivable area based on the current remaining charge of the battery 40 is known, and in that case, for example, as in Patent Document 1 and Patent Document 2, the drivable area is displayed in the omnidirectional direction from the current position of the vehicle. On the other hand, since the traveling direction of the vehicle is determined in a predetermined direction as the vehicle travels, the driver may prefer a display focusing on the traveling direction rather than a display of the drivable area in the omnidirectional direction. Therefore, in this embodiment, the control unit 20 displays the drivable area focusing on the traveling direction that narrows as the vehicle travels. The drivable area display program 21 is a program for performing the display. As described above, since the drivable area display system 10 is realized by a navigation system, the control unit 20 can execute a navigation program (not shown) stored in a ROM or the like. The navigation program is a program that causes the control unit 20 to realize a function of displaying a map including the vehicle's current location on the display unit of the user I/F unit 44 and guiding the driver to the destination.

When the above-mentioned driving area display program 21 is executed, the control unit 20 functions as an acquisition unit 21a and a display control unit 21b. Note that, below, the processes described as being performed by the acquisition unit 21a and the display control unit 21b are processes realized by the control unit 20.

The acquisition unit 21a is a function that acquires the drivable area in which the vehicle can travel with the current remaining charge of the battery 40 from a target range including the vehicle's traveling direction, which narrows as the vehicle travels. Specifically, the control unit 20 calculates the drivable distance, which is the maximum drivable distance that the vehicle can travel, based on the current remaining charge of the battery 40, using the function of the acquisition unit 21a. Then, the control unit 20 draws a circle with the calculated drivable distance as the radius, sets an angle that becomes smaller as the vehicle travels (becomes smaller from the initial value of 360°) as the central angle, and sets the target range as a sector including the traveling direction. In addition, the control unit 20 refers to the map information 30a to acquire multiple points that can be reached from the target range within the drivable distance, and searches for each route from the current position to the multiple points. Note that the multiple points referred to here are points that can be reached within the drivable distance when traveling in a straight line from the current position, and for example, the intersections of the circumference (arc) of the sector and the road described above are the multiple points. The control unit 20 then identifies the change in the remaining charge according to each searched route, and determines the range until the remaining charge falls below a predetermined value (e.g., the lower limit of the remaining charge) as the drivable area. The target range is a range of a predetermined angle (i.e., a central angle) that encompasses the vehicle's traveling direction, and the predetermined angle becomes narrower as the vehicle travels. In other words, the drivable area is narrowed in the traveling direction as the vehicle travels. The control unit 20 acquires the drivable area in this manner using the function of the acquisition unit 21a. A more specific aspect of the control unit 20 will be described later in the flow chart.

The display control unit 21b is a function that displays the drivable area acquired by the function of the acquisition unit 21a on the display unit of the user I/F unit 44. In this embodiment, the control unit 20 uses the function of the display control unit 21b to display the drivable area in different colors according to the change in the remaining charge of the battery 40. That is, when the control unit 20 displays the drivable area on the display unit of the user I/F unit 44, the control unit 20 draws the drivable area acquired by the function of the acquisition unit 21a and displays it superimposed on the map. In addition, at that time, the control unit 20 performs a display using different colors based on the change in the remaining charge according to each route specified by the function of the acquisition unit 21a. For example, an area in which the remaining charge is relatively low in the drivable area is displayed in red, and an area in which the remaining charge is not relatively low is displayed in green. A specific embodiment will be described later in the flowchart.

With this configuration, the range of the drivable area is narrowed down in the direction of travel as the vehicle travels, making it possible to display the drivable area with a focus on the direction of travel.

(2) Driving area display process:
Next, the drivable area display process executed by the control unit 20 will be described. Fig. 2A is a flowchart showing an example of the drivable area display process. The control unit 20 executes the drivable area display process when, for example, the ignition switch of the vehicle is turned on. Note that the flowchart shown in Fig. 2A is repeatedly executed at predetermined short intervals (or after driving a predetermined short distance). Also, this drivable area display process is reset when the ignition switch is turned off or a reset button (not shown) that turns off the drivable area display is operated.

When the driving area display process is started, the control unit 20 first acquires the current remaining charge of the battery 40 using the function of the acquisition unit 21a (step S1). Specifically, the control unit 20 acquires the current remaining charge of the battery 40 from a sensor that outputs information on the remaining charge of the battery 40 via the ECU 60 using the function of the acquisition unit 21a.

Next, the control unit 20 acquires the current position of the vehicle (step S2). Specifically, the control unit 20 acquires the current position of the vehicle based on the output signal of the GNSS receiver 41 by the function of the acquisition unit 21a. The control unit 20 also identifies the current position of the vehicle based on signals from the vehicle speed sensor 42 and the gyro sensor 43 in addition to the signal from the GNSS receiver 41. The vehicle speed sensor 42 and the gyro sensor 43 are used to identify the travel path of the vehicle. The current position is then identified based on the departure position and travel path of the vehicle, and the current position of the vehicle identified based on the departure position and travel path is corrected based on the output signal of the GNSS receiver 41. Note that the order of the process of acquiring the current position in step S2 and the process of acquiring the remaining charge in the above-mentioned step S1 may be reversed.

Next, the control unit 20 acquires a drivable area based on the current position from the target range (step S3). That is, the control unit 20 acquires a drivable area that can be traveled with the current remaining charge of the battery 40, using the function of the acquisition unit 21a. FIG. 2B shows a subroutine for the process of acquiring the drivable area in step S3.

Here, the process of step S3 will be described using the subroutine. First, the control unit 20 acquires the drivable distance, which is the maximum distance the vehicle can travel, based on the remaining charge of the battery 40 (step S30). That is, the control unit 20 uses the function of the acquisition unit 21a to calculate the distance the vehicle can travel based on the current remaining charge of the battery 40. Specifically, the control unit 20 calculates the drivable distance from the product of the average power consumption, which is the travel distance per unit of power in the vehicle, and the remaining charge of the battery 40 acquired in the above-mentioned step S1. The average power consumption may be acquired from the past driving history of the vehicle, or data on the average power consumption of other vehicles of the same model may be used. After calculating the estimated drivable distance in this step S30, the control unit 20 advances the process to step S31.

In step S31, the control unit 20 uses the function of the acquisition unit 21a to specify the target range based on the origin and the current position acquired in step S2. Here, the origin means the point where the ignition switch of the vehicle is turned on (i.e., the starting point of the vehicle) or the point where the driver operates the reset button (not shown) (reset point). As described above, the drivable area display process is executed at predetermined short intervals, but when the ignition switch is turned on (or when the ignition switch is turned on shortly), the current position and the origin are in the same position. In this case, the traveling direction of the vehicle is not specified. Therefore, in this case, the control unit 20 specifies a range of 360° centered on the current position (i.e., the origin) as the target range. Note that this target range gradually narrows from 360° as the traveling direction of the vehicle is determined as the vehicle travels. The details of the gradual narrowing of this target range will be described later.

Next, the control unit 20 uses the function of the acquisition unit 21a to identify multiple intersections between the driving distance acquired in step S30 and major roads, and sets each of these intersections as a provisional destination (step S32). Here, the main road is assumed to be a relatively large road such as a national highway or an expressway. In particular, when the angle of the target range is relatively large, such as 360°, or when the driving distance is several tens of kilometers or more, it is preferable to define a road with a large road width, such as a national highway, as the main road. For convenience of explanation, the main road will be described as a national highway. The control unit 20 refers to the map information 30a and identifies multiple intersections (e.g., 8 points) between the driving distance (e.g., 8 km/kWh x 80% (30 kWh) remaining charge = 240 km) and national highways within the target range identified in the above-mentioned step S31. In other words, the control unit 20 identifies eight points within the 360° target range identified in step S31 that are intersections between a point 240 km from the current position and a national highway. The control unit 20 then sets each of the identified eight points as a provisional destination.

Next, the control unit 20 performs route search from the current position to the provisional destination by using the function of the acquisition unit 21a (step S33). Specifically, the control unit 20 refers to the map information 30a and searches for a route from the current position to each of the eight provisional destinations set in step S32. The route search may be performed using various algorithms, such as Dijkstra's algorithm, A* algorithm, or improved algorithms thereof. The travel cost when searching for a route may be the travel cost included in the map information 30a. The map information 30a includes, for example, the travel cost of each link. The travel cost may be determined by various methods. For example, the travel time obtained from the probe traffic information corresponding to each link or the travel time generated from VICS (registered trademark) information may be regarded as the travel cost. After performing route search to each provisional destination, the control unit 20 advances the process to step S34.

In step S34, the control unit 20 uses the function of the acquisition unit 21a to identify the change in the remaining charge of the battery 40 and identify the point where the remaining charge becomes equal to or less than a predetermined value. Here, the predetermined value is, for example, a lower limit value of the remaining charge of the battery 40, and in this embodiment, the lower limit is set to approximately 20% remaining charge from the viewpoint of battery protection to prevent deterioration of the battery 40. In other words, the control unit 20 identifies the limit point of the drivable area where the remaining charge becomes the lower limit.

Specifically, the control unit 20 identifies the change in the remaining charge of the battery 40 when the vehicle travels along the route to each provisional destination for which the route search was performed in step S33, and identifies the point at which the remaining charge becomes equal to or less than a predetermined value. The change in the remaining charge of the battery 40 may be identified by various methods. For example, the control unit 20 calculates the running load F (i.e., running resistance) per unit time on each of the searched routes, and obtains the amount of work per unit time by multiplying the calculated running load F by the vehicle speed. The running load F can be obtained by the sum of the air resistance (1/2ρCdAv ² ), the rolling resistance (μMg cos θ), the gradient resistance (Mg sin θ), and the acceleration resistance ((M+m)a). This can be expressed by the following formula:
Running load F = 1/2ρCdAv ² + μMg cos θ + Mg sin θ + (M + m) a
For each symbol, ρ indicates a predetermined air density, Cd indicates a predetermined air resistance coefficient for each vehicle, A indicates a predetermined frontal projection area of the vehicle for each vehicle, v indicates a vehicle speed, for example, an average vehicle speed for each link, μ indicates a predetermined rolling friction resistance coefficient, M indicates a vehicle weight, for example, a vehicle weight, g indicates gravitational acceleration, θ indicates a road gradient based on the map information 30a, m indicates an equivalent inertial weight (resistance when rotating the drive system), and a indicates an acceleration, for example, an average acceleration of the vehicle. Note that the road gradient θ may differ for each link, and in that case, the acceleration is corrected to be the average acceleration.

The control unit 20 multiplies the driving load F by the vehicle speed (e.g., the average speed of the vehicle) to calculate the workload per unit time. The control unit 20 then calculates the consumption of the battery 40 per unit time based on the calculated workload. By calculating the consumption of the battery 40 per unit time, the remaining charge of the battery 40 at each position from the current position to the provisional destination can be identified. That is, the remaining charge of the battery 40 at each position on the route to the provisional destination can be identified. In other words, the control unit 20 can identify the relationship between the remaining charge and the distance that can be traveled. This allows the control unit 20 to identify the change in the remaining charge of the battery 40 when traveling along the route to each provisional destination for which a route search has been performed, and to identify the point at which the remaining charge becomes equal to or less than a predetermined value.

The control unit 20 then connects the points (eight points) on each route where the remaining charge has reached a predetermined value to determine the target range of the drivable area. The control unit 20 then ends the processing of the subroutine in FIG. 2B and returns to the flowchart in FIG. 2A.

Returning to the flowchart of FIG. 2A, the control unit 20 displays the drivable area according to the change in the remaining charge (step S4). That is, the control unit 20 uses the function of the display control unit 21b to superimpose the drivable area according to the change in the remaining charge determined in step S34 on a map, and displays the map on the display unit of the user I/F unit 44.

Figure 3 is a diagram showing an example of a display unit in which the drivable area is superimposed on a map. As described above, the vehicle's travel direction is not yet determined when the ignition switch of the vehicle is turned on. Therefore, the target range set to obtain the drivable area is the entire circumference (i.e., a range of 360°) from the current position of the vehicle. Then, polygons connecting eight multiple points on each of the above-mentioned routes are drawn superimposed on the map. In the example shown in Figure 3, each route to the temporary destination is shown with a gray line, and the lines of the polygons connecting the eight multiple points are shown with thick black lines. In the example shown in Figure 3, the area showing the remaining charge of the battery 40 in the range of 60% to 80%, the area showing the remaining charge in the range of 40% to 60%, and the area showing the remaining charge in the range of 20% to 40% are each shown by a polygon connecting eight multiple points. In this embodiment, the display of the drivable area is color-coded according to the change in the remaining charge. Specifically, the control unit 20 shows areas with a remaining charge of 60% to 80% in green on the map, areas with a remaining charge of 40% to 60% in yellow on the map, and areas with a remaining charge of 20% to 40% in red on the map. Note that this color-coded display is just one example, and the display may also be such that the color display changes stepwise, for example, by gradation as the remaining charge decreases. In other words, the control unit 20 may display the appropriate color as long as it can notify (or warn) the driver that the remaining charge is approaching the lower limit.

Next, the process of narrowing the target range in the direction of travel as the vehicle travels and narrowing the drivable area displayed accordingly will be described. Note that the description of the same process as the above-mentioned process will be omitted here. As described above, the drivable area display process shown in FIG. 2A is executed at predetermined short intervals. Therefore, the current position acquired in step S2 changes each time the process is executed. Then, as described in step S31 of the subroutine, the target range of the drivable area acquired in step S3 is specified based on the origin and the current position. In the above-mentioned state immediately after the ignition switch is turned on, the current position and the origin are the same position, so the target range is a range of 360°. However, as the vehicle travels, the direction of travel of the vehicle can be gradually specified, so the control unit 20 narrows the target range from 360°. In other words, the control unit 20 can reduce the central angle of the target range centered on the current position from 360°. Specifically, the control unit 20, for example, draws a perpendicular line to a line connecting the origin and the current position (i.e., draws a line with a central angle of 180°) and specifies the travel direction side as the target range. In other words, the 180° range on the travel direction side narrowed down by drawing the perpendicular line is specified as the target range. In other words, the 180° range on the origin side is excluded from the target range. Note that the method of narrowing down the target range is not limited to 360° to 180°. For example, a line may be drawn so that the central angle of the target range centered on the current position is 270°, and the target range may be narrowed down from the 360° range to a 270° range centered on the current position.

The control unit 20 executes the same process each time it repeatedly executes the driveable area display process, and each time, the target range also changes because the current position changes as the vehicle travels. That is, the control unit 20 identifies the target range based on the current position and the origin each time it executes the process. At that time, the control unit 20 makes the target range of the acquired driveable area narrower in the direction of travel than the target range identified in the routine a predetermined distance before (or a predetermined time before). That is, the central angle of the target range centered on the current position becomes smaller in sequence, such as 180°, 120°, 90°, and 60°. Note that the lower limit of the central angle may be any angle range that allows the target range to be identified, and is assumed to be, for example, around 30°.

In step S32, the control unit 20 uses the function of the acquisition unit 21a to identify multiple points where the driving distance intersects with major roads, and sets each point as a provisional destination. At this time, the target range is narrowed (e.g., narrowed from 360° to 180°) for every predetermined distance (e.g., every few kilometers), but in this embodiment, the control unit 20 maintains the number of multiple points. That is, as described above, in this embodiment, the number of multiple points is set to eight, so the number of eight points is maintained and multiple points are identified. By maintaining the number of multiple points and acquiring the driving area, the same number of points can be identified in a narrower range, so the resolution when acquiring the driving area can be improved. In other words, when the target range is 360°, the eight points exist in all directions around the current position, but by narrowing the target range (e.g., narrowing from 360° to 180°), the range in which the multiple points are located is also narrowed.

The multiple points are intersections between the driving distance from the current position and major roads, but as the target range of the main roads gradually narrows, the number of major roads within the target range may decrease, and in such a case, the number of the multiple points set (e.g., eight) may not be identified. Therefore, the control unit 20 may expand the attributes of the main roads as the target range narrows. In other words, the control unit 20 may target roads such as prefectural roads and narrow streets in addition to national roads and expressways as main roads as the target range narrows.

Then, in step S4, the control unit 20 displays the specified drivable area on the display unit of the user I/F unit 44 by the function of the display control unit 21b. That is, the control unit 20 displays the drivable area with the target range narrowed down on the traveling direction side on the display unit of the user I/F unit 44. FIG. 4 is a diagram showing an example of the display of the display unit, and the current position of the vehicle has moved by the amount that the vehicle has traveled from the display of the drivable area in the state where the ignition switch has just been turned on (i.e., when the current position and the origin coincide) described in FIG. 3. In the example shown in FIG. 4, the vehicle is traveling and moving to the right from the origin. As can be seen from FIG. 4, when the vehicle is traveling, the display of the drivable area is narrowed down to the traveling direction side. In other words, the display on the opposite side to the traveling direction is excluded. In the example shown in FIG. 4, the target range is narrowed down from the 360° range shown in FIG. 3 to a range of about 180°, and the traveling direction is to the right. In addition, the target range of the drivable area is narrowed down as the vehicle travels. That is, the central angle of the target range centered on the current position becomes smaller as the vehicle travels. Although not shown, as the vehicle travels further from the state shown in FIG. 4, the current position moves to the right (including the upper right and lower right) from the position shown in FIG. 4, and the target range is narrowed in the direction of travel.

As described above, in this embodiment, the control unit 20 acquires the drivable area in which the vehicle can be driven with the current remaining charge of the battery 40 from a target range including the traveling direction that becomes narrower as the vehicle drives, and displays the acquired drivable area on the display unit of the user I/F unit 44. As a result, the display unit of the user I/F unit 44 always displays the drivable area including the traveling direction in which the driver is driving, and areas other than the traveling direction are no longer displayed as the vehicle drives. In other words, the drivable area is displayed with a focus on the traveling direction. Therefore, for a driver who prefers a display that focuses on the traveling direction rather than a display of the drivable area in the entire circumference of the vehicle, the annoyance of seeing the drivable area other than the traveling direction can be reduced.

In addition, in this embodiment, since the display of drivable areas other than in the traveling direction is excluded as the vehicle travels, the processing load when the control unit 20 acquires the drivable areas and displays the drivable areas on the display unit can be reduced. That is, the processing load of the control unit 20 can be reduced compared to when the drivable areas are acquired in the entire circumferential direction of the vehicle and the drivable areas in the entire circumferential direction are displayed on the display unit each time the above-mentioned drivable area display process is executed. In other words, the processing load of the control unit 20 is limited to the process of acquiring and displaying the drivable areas in the traveling direction, so the processing speed can be faster compared to the case where the process of acquiring and displaying the drivable areas in the entire circumferential direction of the vehicle is uniformly performed.

In addition, in this embodiment, the range up to when the remaining charge of the battery 40 falls below a predetermined value is regarded as the drivable area. In other words, the point where the charge falls below the predetermined value is regarded as the limit point of the drivable area. This predetermined value is set to, for example, a lower limit value, but it may also be set to any value other than the lower limit value (for example, 50% remaining charge). In this way, since the predetermined value can be set arbitrarily, it is not necessarily limited to the lower limit value, and the range up to when the charge falls below the set predetermined value can be displayed on the display unit as the drivable area.

In addition, in this embodiment, when the control unit 20 displays the drivable area on the display unit of the user I/F unit 44, the control unit 20 displays the drivable area in different colors according to the change in the remaining charge of the battery 40. That is, the control unit 20 displays the drivable area in different colors in stages according to the remaining charge. This makes it easier for the driver to understand how much charge is left and how far the vehicle can travel when looking at the display unit, compared to, for example, a case in which the drivable area is displayed in the same color uniformly without color coding. In other words, visibility can be improved when displaying the drivable area.

In addition, in this embodiment, the control unit 20 acquires multiple intersection points with major roads (e.g., eight) when acquiring the drivable area, but maintains the number of multiple points even if the target range of the drivable area narrows as the vehicle travels. This allows the same number of points to be identified in a narrower range, thereby improving the resolution when acquiring the drivable area. In other words, by maintaining the same number of points, the accuracy of acquiring the drivable area and the accuracy of displaying the drivable area can be improved as the target range narrows.

In addition, in this embodiment, the target range is a range of a predetermined angle that includes the vehicle's traveling direction, and the predetermined angle becomes smaller as the vehicle travels. In other words, the target range gradually narrows, mainly in the vehicle's traveling direction. This makes it possible to omit display of areas that are unlikely to interest the driver (i.e., areas other than the traveling direction), for example, and to avoid or suppress inconveniences such as information required by the driver being buried in information not required by the driver.

(3) Other embodiments:
The above embodiment is an example for implementing the present invention, and various other embodiments can be adopted. In the above embodiment, the control unit 20 displays on the display unit a travelable area that can be traveled from the current position with the current remaining charge of the battery 40. However, depending on the driver, there is a case where the driver travels from the current position (first point) via a predetermined point to a second point that is closer to the first point than the predetermined point. That is, there is a case where the driver returns to the second point from the current position, which is the first point, via a predetermined point, and in such a case, it is preferable to display a travelable area assuming the case where the driver returns. Therefore, in the example of FIG. 5, the control unit 20 displays a travelable area that can be traveled with the current remaining charge of the battery 40 when the driver travels from the current position to a predetermined point and returns. Note that, as such an example, for example, a case where the driver departs from the current position or home to go to a predetermined point and returns to the current position or home (i.e., a round trip between the home or the current position and the predetermined point). Alternatively, a case where the driver departs from home to a predetermined point and travels to a point closer to the predetermined point (a point different from the home). In the example shown in Fig. 5, a process will be described when a round trip mode for traveling between a current position and a predetermined point is set. The round trip mode is set, for example, by the driver operating a switch (not shown). The round trip mode corresponds to the "via mode" in this embodiment of the invention.

Figure 5A is a flowchart showing an example of the driveable area display process executed by the control unit 20 when round trip mode is set, and Figure 5B is a subroutine of step S3. The processes in Figures 5A and 5B include parts similar to the process contents described in Figures 2A and 2B above, so only the parts of the process contents that differ from Figures 2A and 2B will be described here, and other similar process contents will be given the same step numbers and their description will be omitted.

First, in step S100, the control unit 20 determines whether or not the round trip mode is set. As described above, the driver sets the round trip mode (not shown), but if the round trip mode has not yet been set, the control unit 20 waits until the round trip mode is set.

On the other hand, when the round trip mode is set, the control unit 20 advances the process to step S1 and subsequent steps. Steps S1 and S2 are the same as those in the above embodiment. In step S3, the contents of steps S320, S330, and S340 corresponding to steps S32, S33, and S34 of the subroutine in the above embodiment are partially different. Specifically, in step S320, the control unit 20 identifies multiple points of intersection between the drivable distance and the main road, and sets each point as a temporary waypoint. In step S30, the control unit 20 draws a circle at half the distance of the drivable distance calculated from the average power consumption and the remaining charge of the battery 40, and identifies multiple (e.g., eight) points of intersection with the main road. The reason for drawing the circle at half the distance of the drivable distance is to obtain the drivable area in the round trip mode. Here, the control unit 20 draws a circle at half the distance of the drivable distance as an approximate drivable area. The control unit 20 then sets eight points that intersect with major roads as temporary stopovers.

Next, in step S330, the control unit 20 searches for a route from the current position to the provisional waypoint. That is, the control unit 20 searches for a route to each provisional waypoint, for example, by means of the Dijkstra algorithm. Then, in step S340, the control unit 20 determines whether or not it is possible to make a round trip along each of the searched routes, taking into account the driving load and the like described in the above embodiment, and identifies a point where the remaining charge is equal to or less than a predetermined value. In the round trip mode, the road gradient may be different between the outbound and return routes, which may result in a different amount of energy regenerated by the motor 50. Therefore, if the point where the circle that intersects with half the travelable distance drawn in step S320 is set as the waypoint, the amount of power consumed by the battery 40 may differ between the outbound and return routes. For example, it is assumed that it is determined that one of the routes that pass through each provisional waypoint is not able to make a round trip along that route because the charge is 20% insufficient for the round trip along that route. In this case, the control unit 20 takes into account the outbound and return journeys and modifies the tentative waypoint to the nearer side on the route by the distance when the charge is 10%, which is half of the 20% charge. The modified point is then set as the waypoint. The control unit 20 performs similar processing on each of the other routes, and modifies the tentative waypoint when the remaining charge is insufficient or when there is excess charge. In this way, the control unit 20 identifies the change in the remaining charge of the battery 40 when traveling each route, and identifies the point where the remaining charge is equal to or less than a predetermined value. The control unit 20 then connects the points (eight points) on each route where the remaining charge has reached a predetermined value to determine the target range.

Next, the control unit 20 returns the process to step S4 in FIG. 5A and displays the drivable area according to the change in the remaining charge (step S4). That is, the control unit 20 superimposes the drivable area according to the change in the remaining charge on a map based on the change in the remaining charge identified in step S340 by using the function of the display control unit 21b, and displays the map on the display unit of the user I/F unit 44. FIG. 6 is a diagram showing an example of a display unit in which the drivable area is superimposed on a map, and shows the display in the case of the outbound journey. In the example shown in FIG. 6, the display of the drivable area is performed in different colors according to the change in the remaining charge, as in the example of FIG. 3 of the above-mentioned embodiment, but since the example of FIG. 6 is a round-trip mode, it is preferable to make the display different for the outbound journey and the return journey. For example, in the case of the outbound journey, the control unit 20 performs a color-coded display such as green, yellow, and red as the vehicle approaches the intermediate destination. That is, on the outbound journey, the vehicle displays a warning color as it approaches the waypoint to inform the driver that the current remaining charge of the battery 40 will not be enough to return once the waypoint is exceeded. On the other hand, on the return journey, the control unit 20 changes the display color from green to yellow to red as the vehicle returns to the current location.

In the above embodiment, when the drivable area is displayed on the display unit, the display is configured to focus on the direction of travel as the vehicle travels. However, in the round trip mode, the display is not focused on the direction of travel, taking into account the vehicle returning to the current position. In other words, in the round trip mode, the display always focuses on the drivable area in all directions from the current position.

In this way, in the examples shown in Figures 5 and 6, the control unit 20 displays the drivable area in round trip mode. This allows the driver to understand the drivable area when traveling back and forth between the current location and a specified point. In round trip mode, the direction of travel is different for the outbound and return journeys, so the omnidirectional direction becomes the direction of travel. Therefore, even in the examples of Figures 5 and 6, the drivable area is displayed with an emphasis on the direction of travel.

Next, another embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart showing an example of a driveable area display process when the driveable area display system 10 is installed in a vehicle with a cruise control function that drives at a speed arbitrarily set by the driver.

Here, the cruise control function in this embodiment will be described. The cruise control function in this embodiment includes a low-load mode that suppresses the power consumption of the battery 40 more than when there is no limit by limiting the speed of the vehicle to a constant speed that suppresses the load on the motor 50 while realizing a function of keeping the speed of the vehicle constant as conventionally known. Or, it includes a low-load mode that suppresses the power consumption of the battery 40 more than when there is no limit by limiting the operation of the electrical equipment equipped in the vehicle while realizing a function of keeping the speed of the vehicle constant as conventionally known. That is, when setting the low-load mode by suppressing the load on the motor 50, the ECU 60 sets the vehicle speed to a speed that can suppress the load on the motor 50. The cruise control function is usually used on expressways and motorways, and it is assumed that the vehicle speed is set to 100 km/h or the like on expressways. In contrast, in this embodiment, the ECU 60 controls the motor 50 so that the motor 50 is in a relatively light speed range (for example, 70 to 80 km/h) in order to suppress the power consumption of the battery 40. The vehicle speed at which the load on the motor 50 is relatively light may be determined in advance within the legal speed range through experiments, etc. In other words, the rotation speed of the motor 50 at which the load on the motor 50 is light may be determined in advance. The control to keep the vehicle speed constant is executed by the ECU 60. The ECU 60 calculates the difference between the current vehicle speed obtained from the vehicle speed sensor 42, for example, and the target vehicle speed (e.g., 80 km), and outputs a control signal to the motor 50 to control the output rotation speed and output torque of the motor 50 so as to reduce the difference.

When the low-load mode is set by restricting the operation of electrical equipment, the ECU 60 suppresses the consumption of power from the battery 40 by restricting (including turning off) the operation of at least one of the electrical equipment, such as the air conditioner, seat heater, steering heater, audio equipment, etc.

In this way, in this embodiment, it is possible to set cruise control and then set a low-load mode that can reduce power consumption of the battery 40.

When this low-load mode is set, the control unit 20 can display the drivable area when driving in this low-load mode. Specifically, the control unit 20 performs the drivable area display process shown in FIG. 7. Note that the process content of this drivable area display process shown in FIG. 7 is almost the same as the process content explained in FIG. 2A and FIG. 2B above, so the same step numbers are given to the similar process content, the explanation is omitted, and only the parts of the process content that are different are explained.

In step S200 in FIG. 7A, the control unit 20 determines whether or not the low-load mode is set. This low-load mode is set, for example, by the driver operating an operation button such as a switch (not shown). Therefore, if the low-load mode has not yet been set, the control unit 20 waits until the low-load mode is set.

On the other hand, if it is determined that the low load mode is set, the control unit 20 proceeds to step S1 and subsequent steps, acquires the drivable area, and displays the acquired drivable area on the display unit of the user I/F unit 44. In addition, the low load mode reduces power consumption of the battery 40 compared to when the low load mode is not set (i.e., has better power consumption compared to the above-mentioned embodiment), and increases the remaining charge of the battery 40. Since the drivable area is determined by the remaining charge of the battery 40, the drivable area in the low load mode is larger than the drivable area in Figures 3 and 4 described in the above-mentioned embodiment, for example.

In this way, in the embodiment of FIG. 7, the drivable area when the low-load mode is set can be obtained, and the obtained drivable area can be displayed. Therefore, for example, when the driver sets the low-load mode, it is possible to know the drivable area when driving in the low-load mode.

In each of the above-mentioned embodiments, the target vehicle only needs to be able to display the drivable area based on the current amount of remaining energy. In other words, the remaining energy is not limited to the remaining charge of the battery 40, but may be the remaining gasoline fuel. Therefore, the vehicle may be a vehicle equipped with an engine instead of a motor as a driving force source. In addition, the vehicle may be a hybrid vehicle using an engine and a motor as driving force sources, a plug-in hybrid vehicle, a so-called range extender EV equipped with an engine exclusively for generating electricity, etc.

In the above embodiment, the number of intersection points with major roads is described as "8", but the number of points may be any number that allows at least one drivable area to be identified. In other words, the drivable area can be identified if three points, including the current position, can be identified, so the number of intersection points with major roads needs to be at least two.

In addition, in the display of the drivable area, as described in Figs. 3, 4, and 6, the display unit is configured to display the change in the remaining charge to visually inform the driver of the change in the remaining charge. On the other hand, this display may display the drivable time, which is the time during which the vehicle can travel with the current remaining charge of the battery 40, instead of the change in the remaining charge. Specifically, the control unit 20 determines the drivable time with the remaining charge at each position on the route to the provisional destination (or provisional waypoint) taking into account the travel load. Then, the control unit 20 determines a point (limit point) where the determined drivable time is equal to or less than a predetermined time (for example, tens of minutes to 1 hour). Furthermore, the control unit 20 displays the determined drivable area on the display unit of the user I/F unit 44. Fig. 8 is a diagram showing an example of the display unit, and shows the drivable area in the same driving state as the example of Fig. 4 described above. In this example of Fig. 8, the display showing the remaining charge in Fig. 4 is changed to a display of the drivable time. That is, in the example shown in FIG. 8, in each area enclosed by a thick black line based on the vehicle's current position, the available driving time decreases as the vehicle travels from the current position toward the temporary destination. The display of each area enclosed by the thick black line may be the same as the example in FIG. 4, for example, by displaying an area with a driving time of 5 hours in green on the map, an area with a driving time of 3 hours in yellow on the map, and an area with a driving time of 1 hour in red on the map. In this way, by displaying the area on the display unit, it becomes possible for the driver to visually recognize, for example, in which area and at which point the driver can visually recognize how long the driver can travel.

In addition, when displaying the driving area, it is assumed that the driver will operate an operation switch (not shown) or the like to switch between the remaining charge display as shown in FIG. 4 and the driving time display as shown in FIG. 8.

The display of the drivable area may be displayed on the display unit of the user I/F unit 44, or may be displayed on a mobile terminal (not shown) of the driver or the like that can communicate with the drivable area display system 10. In the above-described embodiment, the amount of power consumption per unit time may be calculated based on the amount of work per unit time, or may be obtained from the driving history of other vehicles of the same model.

In addition, each system or device constituting the above-mentioned embodiment may be composed of more devices that share functions. An example of such a case is the system shown in FIG. 1 being composed of one or more other systems. For example, one system may be composed of the drivable area display system 10 and a server. Also, part of the functions of the drivable area display system 10 (at least part of the acquisition unit 21a and the display control unit 21b) may be realized by the drivable area display system 10, and the remaining functions may be realized by another device (e.g., a server). Note that configurations in which some of the configurations of the above-mentioned embodiment are omitted, and configurations in which processing is changed or omitted, are also conceivable.

Furthermore, the techniques of the present invention can also be applied as programs or methods. The above-mentioned systems, programs, and methods may be realized as standalone devices or may be realized by using parts shared with the various parts of the vehicle, and include various aspects. They can also be modified as appropriate, such as being partly software and partly hardware. Furthermore, the invention can also be realized as a recording medium for a program that controls the system. Of course, the recording medium for the program may be a magnetic recording medium or a semiconductor memory, and any recording medium developed in the future can be considered in exactly the same way.

10...Drivable area display system, 20...Control unit, 21...Drivable area display program, 21a...Acquisition unit, 21b...Display control unit, 30...Recording medium, 30a...Map information, 40...Battery, 41...GNSS receiving unit, 42...Vehicle speed sensor, 43...Gyro sensor, 44...User I/F unit, 50...Motor, 60...ECU.

Claims (7)

an acquisition unit that acquires a travelable area in which the vehicle can travel with a current remaining energy amount from a target range including a traveling direction of the vehicle, the target range narrowing as the vehicle travels;
A display control unit that displays the acquired travelable area.
Driving area display system. the vehicle includes a battery that supplies power to a motor that is a driving force source, the remaining energy amount being a remaining charge of the battery,
The acquisition unit is
calculating a maximum distance that the vehicle can travel based on the remaining charge of the battery;
Obtaining a plurality of points that can be reached within the calculated driving distance from the target range;
Searching for a route from the current location to the plurality of points;
A change in the remaining charge amount according to the searched route is identified, and the range until the remaining charge amount becomes equal to or less than a predetermined value is determined as the travelable area.
The driveable area display system according to claim 1 . The display control unit is
Acquire a change in the remaining charge amount while traveling along the route;
The display of the travelable area is performed in a color-coded manner according to a change in the remaining charge.
The driveable area display system according to claim 2 . The number of the plurality of points is maintained even if the target range is narrowed.
The driveable area display system according to claim 2 . The target range is a range of a predetermined angle including a traveling direction of the vehicle, and the predetermined angle becomes smaller as the vehicle travels.
2. The driveable area display system according to claim 1. The acquisition unit is
obtain a travelable area that can be traveled with a current remaining energy amount of the vehicle in a route mode in which the vehicle travels from a first point to a second point closer to the first point via a predetermined point, and
The display control unit is
When the route mode is selected, the travelable area in the route mode is displayed.
The driveable area display system according to claim 1 . The vehicle has a cruise control function that allows the vehicle to travel at a speed arbitrarily set by the driver,
the cruise control function includes a low-load mode that limits the speed to a constant speed or limits the operation of electrical equipment of the vehicle to reduce power consumption of the battery more than in a case where these limitations are not present;
The display control unit is
When the low-load mode is set, the display of the drivable area in the case of driving in the low-load mode is performed.
The driveable area display system according to claim 2 .

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