Driving assistance system
The driving assistance device optimizes charging facility selection based on battery protection thresholds, ensuring efficient and safe charging by avoiding high-output charging near full charge.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- AISIN CORP
- Filing Date
- 2024-12-25
- Publication Date
- 2026-07-07
Smart Images
Figure 2026112896000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a driving support device that supports charging of an in-vehicle battery.
Background Art
[0002] In recent years, in addition to gasoline vehicles driven by an engine as a driving source, there are electric vehicles driven by a motor driven by electric power supplied from a battery and hybrid vehicles driven by a combination of a motor and an engine as driving sources. As a method for charging the in-vehicle battery provided in such electric vehicles and hybrid vehicles, there are a method of charging with regenerative power of the motor generated during deceleration or during driving on a downhill road while the vehicle is running, and a method of charging using a generator driven based on an engine. In addition, there is a method of charging at home or at a dedicated charging facility.
[0003] Here, when the vehicle charges at the above charging facility, if there are a plurality of candidates for charging facilities where charging is possible, it is difficult to determine which charging facility to charge at. Therefore, for example, in Japanese Patent Application Laid-Open No. 2001-112121, after specifying the range in which the vehicle can travel from the current battery remaining amount and displaying it on a map image, when it is difficult to reach the destination with the current battery remaining amount, a technique for displaying a route via a charging stand has been proposed.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In recent years, some charging facilities have been equipped with rapid chargers that increase the amount of energy that can be charged per unit time compared to normal by increasing the output power, in order to increase the amount of energy that can be charged in a shorter time. However, high-output charging using such rapid charging may cause deterioration of the vehicle battery if it is charged when it is close to full charge. Therefore, it is known that when a vehicle battery is charged with a rapid charger, a control function (hereinafter referred to as a protection function) is performed to intentionally reduce the amount of charging energy per unit time in order to protect the vehicle battery as it approaches full charge.
[0006] Therefore, in order to improve the charging efficiency (to perform efficient charging) when charging the vehicle battery, it is necessary to select a charging facility that takes the above-mentioned protection functions into consideration. However, the technology described in Patent Document 1 does not take these protection functions into consideration, which leads to the problem of inviting users to charge at charging facilities with low charging efficiency.
[0007] The present invention was made to solve the aforementioned problems of the conventional system, and aims to provide a driving assistance device that enables efficient charging while taking into consideration the protection function of the vehicle battery. [Means for solving the problem]
[0008] To achieve the above objective, the driving support device according to the present invention includes: a charging facility information acquisition means for acquiring the location of candidate charging facilities among charging facilities capable of charging an on-board battery that supplies power to the vehicle's drive source; a remaining energy amount acquisition means for acquiring the current remaining energy amount of the on-board battery equipped in the vehicle; a protection threshold acquisition means for acquiring a threshold amount of charge at which a protection function that reduces the charging speed is activated when charging the on-board battery equipped in the vehicle; a remaining energy amount estimation means for estimating the remaining energy amount of the on-board battery when the vehicle arrives at the charging facility candidate, based on the current remaining energy amount of the on-board battery, the current location of the vehicle, and the location of the candidate charging facility; and a charging facility selection means for selecting, as a target for charging, a charging facility candidate from among the candidate charging facilities that is reachable by the vehicle and whose remaining energy amount of the on-board battery when it arrives at the charging facility candidate falls within a set range based on the threshold. [Effects of the Invention]
[0009] According to the driving support device of the present invention having the above configuration, by prioritizing the selection of charging facility candidates where the remaining energy amount of the on-board battery upon arrival of the vehicle falls within a set range based on a threshold charge amount that activates the on-board battery's protection function, it becomes possible to enable the user to perform efficient charging. [Brief explanation of the drawing]
[0010] [Figure 1] This is a schematic diagram showing the driving support system according to this embodiment. [Figure 2] This is a block diagram showing the configuration of the driving support system according to this embodiment. [Figure 3] This diagram shows an example of charging facility information stored in the charging facility database. [Figure 4] This diagram explains the fast charging capacity. [Figure 5] This diagram illustrates the relationship between SOC value and charging output. [Figure 6] This is a block diagram showing the navigation device 5 according to this embodiment. [Figure 7] This is a flowchart of the pathfinding processing program according to this embodiment. [Figure 8] This diagram shows the guidance screen for the route displayed on the LCD screen. [Figure 9] This is a flowchart of the sub-processing program for the charging plan planning process. [Figure 10] This diagram illustrates the method for selecting potential charging facilities to be used for charging. [Figure 11] This diagram illustrates the method for selecting potential charging facilities to be used for charging. [Modes for carrying out the invention]
[0011] The following will describe in detail, with reference to the drawings, an embodiment of the driving support device according to the present invention in which the information provision server 1 is materialized. First, the schematic configuration of the driving support system 2 including the information provision server 1 according to this embodiment will be described using Figure 1. Figure 1 is a schematic configuration diagram showing the driving support system 2 according to this embodiment.
[0012] As shown in Figure 1, the driving support system 2 according to this embodiment basically comprises an information provision server 1 located in the information provision center 3 and a navigation device 5, which is an in-vehicle device mounted in the vehicle 4. The information provision server 1 and the navigation device 5 are configured to send and receive electronic data to and from each other via a communication network 7. In this embodiment, the driving support system 2 is equipped with a navigation device 5, which is an in-vehicle device, as a means of acquiring information about the vehicle 4 and providing information to the user. However, instead of the navigation device 5, a communication terminal owned by the user, such as a mobile phone, smartphone, or tablet terminal, which is connected to the vehicle 4 in a way that allows communication, may be provided.
[0013] Further, the vehicle 4 is a vehicle equipped with at least a motor as a drive source and an in-vehicle battery 8 as means for supplying power to the motor serving as the drive source, and is a vehicle capable of charging the in-vehicle battery 8 at a charging facility. Applicable vehicles include electric vehicles (hereinafter referred to as EV vehicles) that use only a motor as a drive source, and among hybrid vehicles that use both a motor and an engine as drive sources, particularly plug-in hybrid vehicles (hereinafter referred to as PHV vehicles). Hereinafter, the vehicle 4 will be described assuming it is an EV vehicle.
[0014] Here, the information providing server 1 is capable of performing route search in response to a request from the navigation device 5. Specifically, when a destination is set in the navigation device 5 or when re-searching (rerouting) a route, information necessary for route search such as the departure location and destination is transmitted from the navigation device 5 to the information providing server 1 together with a route search request (however, in the case of re-search, information regarding the destination does not necessarily need to be transmitted). Then, the information providing server 1 that has received the route search request performs route search using the map information possessed by the information providing server 1 and specifies a recommended route from the departure location to the destination. Thereafter, the specified recommended route is transmitted to the navigation device 5 that is the request source. Then, the navigation device 5 provides the user with information regarding the received recommended route, sets the recommended route as a guidance route, and performs movement guidance according to the guidance route. Thereby, even when the map information possessed by the navigation device 5 at the time of route search is old version map information or when the navigation device 5 does not have map information itself, it is possible to provide an appropriate recommended route to the destination based on the latest version map information possessed by the information providing server 1.
[0015] Further, in addition to the map information for performing the above route search, the information providing server 1 also has information regarding information providing locations across the country. In the present embodiment, it has information regarding at least a charging facility 10 where the in-vehicle battery 8 can be charged as an information providing location.
[0016] Here, the charging facility 10 is a facility capable of charging the in-vehicle battery 8 provided in the vehicle 4. It has a parking space for parking the vehicle, and generally, charging equipment consisting of an operation panel, a cable connected to the vehicle, etc. is installed around the parking space. In addition to dedicated facilities for charging vehicles, the charging facility 10 may also be provided in a part of the parking lot of commercial facilities such as shopping malls and service areas, automobile sales stores, coin parking lots, etc.
[0017] Also, the information providing server 1 is communicably connected to a charging facility management server that manages charging facilities 10 across the country. And it can obtain the current availability status of the chargers provided in the charging facility 10 and other information regarding the charging facility 10 (for example, the number of chargers, the maximum output of the chargers, the charging upper limit time, available time bands, usage fees, congestion status, compatible vehicle types, etc.).
[0018] When the energy (remaining battery level) stored in the in-vehicle battery 8 is insufficient for the energy required to travel to the destination, the information providing server 1 also formulates a charging plan based on the route to the destination and the information regarding the charging facility 10 and provides it to the user.
[0019] However, it is not necessarily required to perform the above-described route search process and charging plan formulation by the information providing server 1. If it is a navigation device 5 having map information and information regarding charging facilities, the navigation device 5 may perform them.
[0020] Furthermore, the navigation device 5 is mounted in the vehicle 4 and is an in-vehicle device that displays a map of the area around the vehicle's position based on map data held by the navigation device 5 or map data acquired from an external source, displays the vehicle's current position on the map image, and provides navigation guidance along a set route. In addition, the navigation device 5 is connected to the vehicle control ECU and battery level meter mounted in the vehicle 4 via an in-vehicle network such as CAN, and is able to acquire information regarding the on-board battery 8 (for example, the current remaining energy amount, the maximum amount of energy that can be charged per unit time for the on-board battery determined for each vehicle, and the energy efficiency performance (driving range per unit of energy), etc.).
[0021] Furthermore, the communication network 7 includes numerous base stations located throughout the country and communication companies that manage and control each base station, and is constructed by connecting the base stations and communication companies to each other via wired (optical fiber, ISDN, etc.) or wireless connections. Here, each base station has a transceiver (transceiver) and antenna that communicates with the navigation device 5. In addition to conducting wireless communication between communication companies, the base stations also act as the end of the communication network 7 and relay communications from the navigation device 5 within the range (cell) of the base station's radio waves to the information provision server 1.
[0022] Next, the configuration of the information provision server 1 in the driving support system 2 will be explained in more detail using Figure 2. As shown in Figure 2, the information provision server 1 comprises a server control unit 11, a server-side map DB 12 as an information recording means connected to the server control unit 11, a charging facility DB 13, and a server-side communication device 15.
[0023] The server control unit 11 is a control unit (MCU, MPU, etc.) that controls the entire information provision server 1, and is equipped with a CPU 21 as an arithmetic unit and control device, a RAM 22 used as working memory when the CPU 21 performs various arithmetic processing, a ROM 23 on which control programs are recorded, and a flash memory 24 for storing programs read from the ROM 23, among other internal storage devices. The server control unit 11, together with the ECU of the navigation device 5 described later, has various means as processing algorithms. For example, the charging facility information acquisition means acquires the location of candidate charging facilities from among the charging facilities 10 that are capable of charging the on-board battery 8 that supplies power to the vehicle's drive source. The remaining energy amount acquisition means acquires the current remaining energy amount of the on-board battery 8 equipped in the vehicle. The protection threshold acquisition means acquires the charge amount threshold at which a protection function that reduces the charging speed is activated when charging the on-board battery 8 equipped in the vehicle. The remaining energy amount estimation means estimates the remaining energy amount of the on-board battery 8 when the vehicle arrives at a charging facility candidate, based on the current remaining energy amount of the on-board battery 8, the current location of the vehicle, and the location of the charging facility candidate. The charging facility selection means prioritizes selecting charging facility candidates from among the charging facility candidates that are reachable by the vehicle and whose remaining energy amount of the on-board battery 8 upon arrival falls within a set range based on a threshold, and uses these as the target for charging. The post-charging remaining energy amount estimation means estimates the remaining energy amount of the on-board battery after charging, based on the remaining energy amount of the on-board battery upon arrival at the charging facility candidate and the maximum charging time, for each charging facility candidate. In other words, the server control unit 11 is an example of a charging facility information acquisition means, a remaining energy amount acquisition means, a protection threshold acquisition means, a remaining energy amount estimation means, a charging facility selection means, and a post-charging remaining energy amount estimation means.
[0024] On the other hand, the server-side map DB12 is a storage means that stores server-side map information, which is the latest version of map information registered based on external input data and input operations. Here, the server-side map information contains various information necessary for route searching, route guidance, and map display, including road networks. For example, it contains network data including nodes and links that show road networks, link data related to roads (links), node data related to node points, intersection data related to each intersection, location data related to locations such as facilities, map display data for displaying maps, search data for searching for routes, and search data for searching for locations.
[0025] Furthermore, the charging facility DB13 is a memory device that stores various information, particularly regarding the charging facilities 10 located throughout the country. Here, a "charging facility" is a facility capable of charging the on-board battery 8 of a vehicle 4, and typically includes a parking space for parking vehicles, and charging equipment consisting of an operation panel and cables for connecting to the vehicle is installed around the parking space. In addition to facilities dedicated to charging vehicles, the above-mentioned charging facilities 10 may also be installed in parts of parking lots of commercial facilities such as shopping malls, car dealerships, coin-operated parking lots, etc.
[0026] Here, Figure 3 shows an example of the information stored in the charging facility DB13. As shown in Figure 3, for each of the 10 charging facilities located throughout the country, the facility ID, facility name (or the name of the other facility if it is located within a larger facility), location of the charging facility, maximum output (kW) and number of installed chargers, maximum charging time, and current availability information are stored. Here, "maximum charger output" is expressed in watts, i.e., power, and corresponds to the amount of energy that can be charged per unit time by that charger. A charger with a higher maximum output can charge more energy for the same charging time. However, this is only the maximum output, so the actual output may be less than that value depending on the circumstances. Specifically, each vehicle has a rapid charging capacity, which is the maximum amount of energy that can be charged per unit time by the onboard battery (determined by the battery voltage of the onboard battery 8, etc.). As shown in Figure 4, even if you charge with an 80kW charger, if the vehicle's rapid charging capacity is 50kW, you can only input a maximum of 50kW. Furthermore, during charging of the vehicle battery 8, the amount of energy (W) that can be input per unit time, i.e., the charging speed, gradually decreases as the vehicle battery 8 approaches full charge. In particular, once the vehicle battery 8 approaches full charge, a control is implemented that significantly reduces the amount of energy (W) that can be input per unit time to prevent degradation of the vehicle battery 8. This control is called a protection function. When the protection function is activated, for example, if the threshold is 70%, the amount of energy (W) that can be input per unit time will decrease significantly, especially when the SOC value is 70% or more of full charge, as shown in Figure 5. Therefore, when charging the vehicle battery 8, charging within the range where the remaining capacity does not exceed the above threshold is the most efficient charging method (more energy can be charged in the same amount of time). Note that the 70% threshold for the activation of the protection function is merely an example, and this value is set in various ways depending on the vehicle model. It may also change depending on the charging environment. On the other hand, the "maximum charging time" indicates the maximum time that can be charged in a single charge at a charging facility, and even if the onboard battery 8 is not fully charged, charging cannot be continued for more than the maximum time.
[0027] For example, in the charging facility DB13 shown in Figure 3, there are four chargers with a maximum output of 80kW in the parking lot of “○○ Service Area” at location coordinates (x1, y1), with a maximum charging time of 30 minutes, indicating that the chargers are currently busy. Also, there are two chargers with a maximum output of 40kW in the parking lot of “×× Parking” at location coordinates (x2, y2), with a maximum charging time of 30 minutes, indicating that the chargers are currently available. Furthermore, there are four chargers with a maximum output of 60kW at the dedicated charging station “〇× Stand” at location coordinates (x3, y3), with a maximum charging time of 30 minutes, indicating that the chargers are currently available. The information provision server 1 can obtain information such as the usage status of charging facilities from the charging facility management server that manages charging facilities 10 throughout the country. In addition, the charging facility DB13 may also store information about charging facilities other than the above information (e.g., usage fees, available hours, compatible vehicle types, etc.).
[0028] On the other hand, the server-side communication device 15 is a communication device for communicating with the navigation device 5, which is the target of information transmission and reception, via the communication network 7. In addition to the navigation device 5, it is also possible to receive traffic information consisting of various types of information such as congestion information, regulation information, and traffic accident information transmitted from the Internet network and traffic information centers, such as VICS (registered trademark: Vehicle Information and Communication System) centers.
[0029] Next, the schematic configuration of the navigation device 5 installed in the vehicle 4 will be explained using Figure 6. Figure 6 is a block diagram showing the navigation device 5 according to this embodiment.
[0030] As shown in Figure 6, the navigation device 5 according to this embodiment includes a current location detection unit 31 that detects the current location of the vehicle on which the navigation device 5 is installed, a data recording unit 32 on which various data are recorded, a navigation ECU 33 that performs various calculations based on the input information, an operation unit 34 that accepts operations from the user, a liquid crystal display 35 that displays information such as a map of the area around the vehicle, information on the driving route, and a charging plan to the user, a speaker 36 that outputs voice guidance regarding route guidance, a DVD drive 37 that reads a DVD which is a storage medium, and a communication module 38 that communicates with information centers such as an information provision server 1, a charging facility management server, and a VICS center. The navigation device 5 is also connected to a battery level meter 39 installed in the vehicle 4 via an in-vehicle network such as CAN.
[0031] The following describes each component of the navigation device 5 in order. The current position detection unit 31 consists of a GPS 41, a vehicle speed sensor 42, a steering sensor 43, a gyro sensor 44, etc., and is capable of detecting the current position, direction, vehicle speed, current time, etc. In particular, the vehicle speed sensor 42 is a sensor for detecting the distance traveled and vehicle speed of the vehicle, and generates pulses in accordance with the rotation of the vehicle's drive wheels and outputs the pulse signal to the navigation ECU 33. The navigation ECU 33 then calculates the rotation speed of the drive wheels and the distance traveled by counting the generated pulses. It should be noted that the navigation device 5 does not need to be equipped with all four types of sensors mentioned above, and the navigation device 5 may be configured to be equipped with only one or more of these types of sensors.
[0032] Furthermore, the data recording unit 32 includes a hard disk (not shown) as an external storage device and recording medium, and a recording head (not shown) which is a driver for reading map information DB 45 and predetermined programs recorded on the hard disk, and for writing predetermined data to the hard disk. The data recording unit 32 may be configured with flash memory, a memory card, or an optical disc such as a CD or DVD instead of a hard disk. Also, in this embodiment, as described above, the information provision server 1 searches for a route to the destination, so the map information DB 45 may be omitted.
[0033] Here, the map information DB45 is a storage means that stores, for example, link data related to roads (links), node data related to node points, search data used for processing related to route searching and modification, facility data related to facilities, map display data for displaying maps, intersection data related to each intersection, and search data for searching for locations.
[0034] On the other hand, the navigation ECU (Electronic Control Unit) 33 is an electronic control unit that controls the entire navigation device 5, and includes a CPU 51 as an arithmetic unit and control device, a RAM 52 which is used as working memory when the CPU 51 performs various arithmetic processing and stores route data when a route is searched, a planned charging plan, etc., a ROM 53 which stores control programs etc., and a flash memory 54 which stores programs read from the ROM 53.
[0035] The control unit 34 is operated when inputting the starting point (departure point) and the ending point (destination point), and has multiple operation switches (not shown), such as various keys and buttons. The navigation ECU 33 controls the system to perform various operations based on the switch signals output when each switch is pressed. The control unit 34 may also have a touch panel located in front of the liquid crystal display 35. It may also have a microphone and a voice recognition device.
[0036] The liquid crystal display 35 is a type of display device that shows map images including roads, traffic information, operation instructions, operation menus, key instructions, guidance information along the guided route (planned driving route), charging plan instructions, news, weather forecasts, time, emails, TV programs, and more.
[0037] Furthermore, speaker 36 outputs voice guidance that directs the driver along the guided route (planned route) based on instructions from the navigation ECU 33, as well as traffic information.
[0038] Furthermore, the DVD drive 37 is a drive capable of reading data recorded on recording media such as DVDs and CDs. Based on the read data, it performs functions such as playing music and videos, and updating the map information DB 45. Alternatively, a card slot for reading and writing memory cards may be provided instead of the DVD drive 37.
[0039] Furthermore, the communication module 38 is a communication device for receiving traffic information, weather information, etc., transmitted from traffic information centers, such as VICS centers or other external centers, and examples include mobile phones and DCMs. It also includes vehicle-to-vehicle communication devices for communication between vehicles and vehicle-to-infrastructure communication devices for communication with roadside units. It is also used to send and receive information with the information provision server 1.
[0040] Furthermore, the battery level indicator 39 is a sensor for detecting the remaining energy amount of the onboard battery 8 of the vehicle equipped with the navigation system 5.
[0041] Next, the route search processing program executed in the communication terminal 6 having the above configuration will be described with reference to Figure 7. Figure 7 is a flowchart of the route search processing program according to this embodiment. Here, the route search processing program is executed when a predetermined operation to start route searching is received in the navigation device 5, and searches for a route to the destination in accordance with the user's operation. Furthermore, if the energy (remaining power) stored in the onboard battery 8 is insufficient for the energy required to travel to the destination, the program plans and provides a charging plan. The programs shown in the flowcharts in Figures 7 and 9 below are stored in the RAM 22, ROM 23, etc., of the information provision server 1 and are executed by the CPU 21.
[0042] First, in step 1 (hereinafter abbreviated as S), the CPU 21 determines whether or not it has received a route search request from the navigation device 5. The route search request includes a terminal ID that identifies the navigation device 5 that sent the route search request, and information that identifies the departure point (e.g., the vehicle's current location) and the destination.
[0043] If it is determined that a route search request has been received from the navigation device 5 (S1:YES), the process proceeds to S2. Conversely, if it is determined that a route search request has not been received from the navigation device 5 (S1:NO), the route search processing program is terminated.
[0044] In S2, the CPU 21 uses the route search request received in S1 and the map information held by the information provision server 1 to perform route search processing from the starting point to the destination and identify a recommended route from the starting point to the destination. For example, the well-known Dijkstra's algorithm is used to search for the recommended route, and the route with the minimum total cost value is selected as the recommended route. The searched recommended route to the destination is then used as the guided route to guide the user in the navigation device 5. The estimated time of arrival at the destination is also calculated, taking into account the route length and traffic congestion information, etc. If there are multiple recommended routes, the user may be presented with multiple recommended routes, and the route selected by the user from among the multiple recommended routes may be set as the guided route.
[0045] Subsequently, in S3, the CPU 21 obtains the current SOC value (the ratio of remaining energy to a full charge of the onboard battery 8) for the vehicle 4 in which the user is riding. It also obtains the vehicle's energy consumption (the distance that can be traveled per unit of energy). The SOC value and energy consumption are obtained via the navigation device 5. The navigation device 5 can obtain this information from the vehicle control ECU and battery level meter installed in the vehicle 4 via an onboard network such as CAN.
[0046] Subsequently, in S4, the CPU 21 predicts the amount of energy (power consumption) that would be consumed for each link included in the guidance route, assuming that the vehicle 4 travels to the destination according to the guidance route set in S2. The amount of energy consumed when assuming travel through each link is calculated by considering not only the link length and energy consumption, but also the gradient of the route, traffic information, and the vehicle's travel history.
[0047] Subsequently, in S5, the CPU 21 determines, based on the power consumption for each link calculated in S4, whether the SOC value obtained in S3 is insufficient for the energy required to travel to the destination.
[0048] If it is determined that the current SOC value is insufficient for the energy required to travel to the destination (S5:YES), the process proceeds to S6. Conversely, if it is determined that the current SOC value is sufficient for the energy required to travel to the destination (S5:NO), the guidance route set in S2 is finalized and transmitted to the navigation device 5 that sent the route search request (S10).
[0049] In S6, the CPU 21 executes the charging plan formulation process (Figure 9), which will be described later. The charging plan formulation process is the process of formulating a charging plan for charging the vehicle's onboard battery 8 during the journey to the destination. The charging plan includes information specifying the charging facilities selected as targets for charging, the scheduled time to start charging at those facilities, and the charging time at those facilities. However, the charging plan may only specify the charging facilities to be charged and their order. When selecting the charging facilities to be charged, priority is given to selecting charging facilities that can efficiently charge the onboard battery 8, as will be described later. Details will be described later.
[0050] Subsequently, in S7, the CPU 21 determines whether, when the vehicle's onboard battery 8 is charged according to the charging plan formulated in S6, the SOC value will not be insufficient to reach the destination and the vehicle will arrive at the destination.
[0051] Then, if it is determined that the vehicle can reach its destination after charging the onboard battery 8 of the vehicle 4 according to the charging plan formulated in S6 (S7: YES), the process proceeds to S8. On the other hand, if it is determined that the vehicle cannot reach its destination even after charging the onboard battery 8 of the vehicle 4 according to the charging plan formulated in S6 (S7: NO), the process proceeds to S9.
[0052] In S8, the CPU 21 modifies the guidance route set in S2 by incorporating the charging plan formulated in S6. Specifically, it adds charging facilities to be used as waypoints on the journey to the destination. The charging facilities to be used are basically selected from those located along the guidance route, but "along the guidance route" does not necessarily mean that they are adjacent to the guidance route; charging facilities within a predetermined distance (e.g., 300m) from the guidance route are also included. Therefore, the shape of the guidance route may change when waypoints are added. The estimated arrival time at the destination is also modified, taking into account the time required for charging at the charging facilities. The process then proceeds to S10.
[0053] Meanwhile, in S9, the CPU 21 adds information to the guidance route set in S2 indicating that the current SOC value is insufficient to reach the destination specified by the user. The process then proceeds to S10.
[0054] In S10, the CPU 21 transmits information regarding the guidance route set in S2 (including information modified or added in S8) to the navigation device 5, the source of the route search request. The information regarding the guidance route includes information identifying the sequence of links included in the guidance route and the estimated time of arrival at the destination. If a charging plan was formulated in S6, it also includes information identifying the charging facility selected as the target for charging and the charging time at that charging facility. Subsequently, the navigation device 5, having received information from the information provision server 1 in S10, provides the user with information regarding the guidance route using the liquid crystal display 35 and speaker 36.
[0055] Here, Figure 8 illustrates an example of providing information about the guidance route to the user using the liquid crystal display 35 of the navigation device 5. For example, in the example shown in Figure 8, the liquid crystal display 35 displays the entire route diagram 61 of the guidance route and the estimated time of arrival at the destination. If a charging plan is formulated in S6, the charging facility icon 62 indicating the location of the charging facility to be charged is also displayed in the entire route diagram 61. In addition, an information window 63 displaying more detailed information about the charging facility to be charged is also displayed on the right side of the screen. As a result, the user can understand the charging facility to be charged along with the route to the destination in advance. If information is added in S9 indicating that the user cannot reach the destination specified by the user with the current SOC value, the system will suggest, for example, changing the destination or, if the starting point is home, charging additionally. However, the above example is not the only way to provide information about the guidance route to the user, and any method may be used. For example, the system may provide voice guidance on when to charge and where to charge after the user has started driving.
[0056] Next, the subprocessing of the charging plan formulation process executed in S6 will be explained with reference to Figure 9. Figure 9 is a flowchart of the subprocessing program for the charging plan formulation process.
[0057] First, in S21, the CPU 21 reads the charging time T parameter stored in flash memory and assigns the initial value of 0 [min]. In the charging plan planning process, from S23 onwards (described later), charging facilities to be used for charging are selected sequentially along the guided route starting from the departure point. The charging time T is a parameter that indicates the total charging time at the charging facilities selected so far. The final charging time T is used to calculate the estimated time of arrival at the destination.
[0058] Next, in S22, the CPU 21 reads the power remaining amount P, a parameter stored in flash memory, and assigns it to the initial value, which is the current SOC value of the vehicle 4. The current SOC value of the vehicle 4 is obtained in S3. In the charging plan planning process, from S23 onwards, the charging facilities to be used for charging are selected sequentially along the guided route starting from the departure point. The power remaining amount P is a parameter that indicates the expected remaining amount of the onboard battery 8 after charging at the charging facilities selected so far.
[0059] Next, in S23, the CPU 21 searches for candidate charging facilities, which are charging facilities that can be used to charge the onboard battery 8 while traveling along the guided route to the destination. Basically, charging facilities located along the guided route to the destination obtained in S2 are searched for, but "along the guided route" does not necessarily mean that the facility is adjacent to the guided route; it also includes charging facilities within a predetermined distance (e.g., 300m) from the guided route. The location of the charging facilities necessary to search for candidate charging facilities can be obtained from the charging facility DB 13 (Figure 3).
[0060] The subsequent processing in S24 to S34 is performed on all charging station candidates extracted in S23, starting with those closest to the departure point. Specifically, it is determined sequentially whether or not to select each charging station candidate for charging the onboard battery 8, starting with those closest to the departure point. After processing in S24 to S34 for all charging station candidates extracted in S23, the process proceeds to S35.
[0061] First, in S24, the CPU 21 predicts the amount of energy (power consumption) to be consumed during the journey to the target charging station candidate, assuming that the vehicle will stop at the target charging station candidate on its way to the destination. Furthermore, it uses the current remaining power P to predict the State of Charge (SOC) value upon arrival at the target charging station candidate. It is desirable that the amount of energy consumed when assuming the vehicle has traveled to the target charging station candidate be calculated by considering not only the route length from the starting point or the charging station selected for the previous charge to the target charging station candidate, but also factors such as fuel efficiency, route gradient, traffic information, and vehicle travel history. If the target charging station candidate is not adjacent to the guided route, the CPU 21 searches for a recommended route again using the charging station candidate as a waypoint, and predicts the SOC value using the searched recommended route as the new guided route.
[0062] Next, in S25, the CPU 21 determines whether or not it can reach the target charging facility candidate based on the SOC value at the time of arrival at the target charging facility candidate predicted in S24. Specifically, it determines that it can reach the target charging facility candidate if the SOC value predicted in S24 is equal to or greater than a predetermined lower limit. The lower limit may be 0, but a certain margin is provided, for example, by setting it to 10%. Also, if the amount of energy consumed to travel to the target charging facility candidate is greater than the current remaining power P, it is naturally determined that it cannot reach the charging facility candidate.
[0063] If it is determined that the vehicle can reach the candidate charging facility to be processed (S25: YES), the process proceeds to S26. Conversely, if it is determined that the vehicle cannot reach the candidate charging facility to be processed (S25: NO), the process proceeds to S30.
[0064] In S26, the CPU 21 determines whether the SOC value at the time of arrival of the charging facility candidate to be processed, as predicted in S24, is within the set range based on the threshold that serves as the activation condition for the protection function, and whether it is insufficient to reach the destination.
[0065] Then, if the SOC value at the time of arrival at the charging station candidate predicted in S24 is within the set range, and it is determined that it is insufficient to reach the destination (S26: YES), the charging station candidate is selected as a charging target for charging the onboard battery 8 (S27). On the other hand, if the SOC value at the time of arrival at the charging station candidate predicted in S24 is not within the set range, or it is determined that it is sufficient to reach the destination (S26: NO), the charging station candidate is not selected as a charging target for charging the onboard battery 8. After that, the processing from S24 onwards is executed again with the next charging station candidate on the destination side along the guided route as the new processing target. The details of the processing in S26 and S27 are described below.
[0066] As mentioned above, when charging the on-board battery 8 at a charging facility, control is implemented to significantly reduce the amount of energy (W) that can be input per unit time, i.e., the charging speed, once the on-board battery 8 approaches full charge (for example, 70%), in order to prevent degradation of the on-board battery 8 (see Figure 5). Therefore, when charging the on-board battery 8, charging within a range where the remaining capacity does not exceed the threshold is the most efficient charging method (more energy can be charged in the same amount of time). In this embodiment, the CPU 21 first obtains the maximum charging time set for the candidate charging facility, and estimates the amount of remaining energy in the on-board battery after charging when the vehicle charges at the candidate charging facility, based on the remaining energy of the on-board battery upon arrival at the candidate charging facility, the maximum charging time, and the vehicle's rapid charging capacity (however, if the charger's maximum output is less than the rapid charging capacity, the maximum output is used). The setting range that serves as the judgment condition in S26 is the range in which the amount of remaining energy in the on-board battery after charging when the vehicle charges at the candidate charging facility is less than or equal to the threshold.
[0067] As a result, charging facility candidates whose SOC value at arrival is determined to be within the set range can be determined to be charging facility candidates that can perform efficient charging within a range where the remaining capacity of the onboard battery 8 does not exceed the threshold, and are therefore selected as charging targets with priority. For example, as shown in Figure 10, if there are charging facility candidates a and charging facility candidates b along the guidance route, and the set range for both is 20% or less, first the processing from S24 onwards is performed on charging facility candidate a, but since the SOC value at the time the vehicle arrives at charging facility candidate a is 6 / 20 = 30%, it is not selected as a charging target (S26: NO). Next, the processing from S24 onwards is performed on charging facility candidate b, but since the SOC value at the time the vehicle arrives at charging facility candidate b is 3 / 20 = 15%, it is selected as a charging target (S26: YES). However, as an exception, even if the SOC value at arrival is within the set range, if it is possible to reach the destination without charging, it is more efficient not to charge, so the charging facility candidates being processed are not selected as charging targets.
[0068] Furthermore, assuming that the maximum charging time set for each candidate charging facility is a fixed time (e.g., 30 minutes) and does not change from facility to facility, and that the maximum output of the charger provided by each candidate charging facility exceeds the vehicle's fast charging capacity, the amount of energy that can be charged to the on-board battery 8 in one charging operation will be the same for all candidate charging facilities. In that case, the setting range will also be common, and it is possible to set the setting range to a fixed value of 20% or less, for example. On the other hand, the setting range may be set to a different range for each candidate charging facility being processed. In addition, the setting range may be changed according to the vehicle's battery performance (e.g., the value of the vehicle's fast charging capacity), i.e., it may be changed for each vehicle.
[0069] Then, in S28, which is executed when a candidate charging facility to be processed is selected as the charging target for charging the on-board battery 8, the CPU 21 reads the remaining power P parameter stored in flash memory, calculates the remaining energy of the on-board battery after charging when the vehicle charges at the candidate charging facility to be processed, and substitutes it. The remaining energy of the on-board battery after charging when the vehicle charges at the candidate charging facility to be processed can be calculated based on the remaining energy of the on-board battery when the vehicle arrives at the candidate charging facility, the maximum charging time, and the vehicle's rapid charging capacity (however, if the charger's maximum output is less than the rapid charging capacity, the maximum output is used).
[0070] Next, in S29, the CPU 21 reads the charging time T, which is a parameter stored in flash memory, and adds the maximum charging time (e.g., 30 minutes) of the candidate charging facility to be processed. After that, the process from S24 onwards is executed again, with the next candidate charging facility on the destination side along the guidance route as the new target.
[0071] Furthermore, since processes S24 to S34 are executed in order from the nearest charging station to the starting point, if there are multiple charging station candidates that meet the conditions of S25 and S26, the charging station candidate closest to the vehicle's current location will be selected as the target for charging. As a result, it is possible to improve charging efficiency while reducing the risk of insufficient battery charge.
[0072] On the other hand, in S30, which is executed when it is determined in S25 that the target charging station candidate cannot be reached (S25:NO), the CPU 21 determines whether there is a charging station candidate that has not been selected as a target charging station one stop before the target charging station candidate (towards the departure point).
[0073] Then, if it is determined that there is a charging station candidate that has not been selected as a charging station candidate one stop before the charging station candidate to be processed (on the departure side) (S30: YES), the charging station candidate one stop before the charging station candidate to be processed (on the departure side) is selected as the charging station target for charging the onboard battery 8 (S31). On the other hand, if it is determined that there is no charging station candidate that has not been selected as a charging station candidate one stop before the charging station candidate to be processed (on the departure side) (S30: NO), it is determined that the destination cannot be reached with the devised charging plan (S37). Subsequently, information indicating that the destination specified by the user cannot be reached with the current SOC value is added to the guidance route (S9), and the user is guided accordingly. The details of the processing in S30 and S31 are described below.
[0074] For example, as shown in Figure 11, if there are two candidate charging facilities, c and d, along the guidance route, and the setting range for both is 20% or less, the following will be explained: First, the process from S24 onwards is performed on candidate charging facility c. However, when the vehicle arrives at candidate charging facility c, the SOC value is 5 / 20 = 25%, so it is not selected as a charging target (S25: YES, S26: NO). Next, the process from S24 onwards is performed on candidate charging facility d. If it is determined that the SOC value is insufficient and the vehicle cannot reach candidate charging facility d (S25: NO), candidate charging facility c, which was not initially selected as a charging target, will be selected again as a charging target (S31).
[0075] In this embodiment, charging facility candidates that enable efficient charging are prioritized for selection as charging targets. Therefore, charging facility candidates that are reachable by the vehicle but whose remaining energy level in the on-board battery 8 upon arrival is not within the set range (S25:YES, S26:NO) are generally excluded from the charging targets. However, if charging is not performed at that charging facility candidate, the vehicle will not be able to reach the next charging facility candidate or the destination, then charging at that charging facility candidate becomes necessary, and it is selected as a target for charging (S31).
[0076] Subsequently, in S32, the CPU 21 reads the remaining power P parameter stored in flash memory and calculates and substitutes the remaining energy of the onboard battery after charging if the vehicle had charged at a charging facility candidate located one stop before (towards the departure point) the target charging facility candidate. The remaining energy of the onboard battery after charging if the vehicle had charged at the charging facility candidate one stop before can be calculated based on the remaining energy of the onboard battery upon arrival at the charging facility candidate, the maximum charging time, and the vehicle's rapid charging capacity (however, if the charger's maximum output is less than the rapid charging capacity, the maximum output is used).
[0077] Next, in S33, the CPU 21 reads the charging time T, which is a parameter stored in flash memory, and adds the maximum charging time (for example, 30 minutes) of the charging facility candidate located one stop before the target charging facility candidate (towards the departure point).
[0078] Next, in S34, the CPU 21 assumes that charging has been performed at a candidate charging facility located one stop before the target charging facility candidate (towards the departure point), and then determines whether it can reach the target charging facility candidate again. The details are the same as in S25 above, so the explanation is omitted.
[0079] If it is determined that the vehicle can reach the target charging station candidate (S34: YES), the process proceeds to S26. On the other hand, if it is determined that the vehicle cannot reach the target charging station candidate even if it charges at a charging station candidate one stop before the target charging station candidate (on the departure side) (S34: NO), it is determined that the planned charging plan will not allow the vehicle to reach the destination (S37). Subsequently, information indicating that the vehicle cannot reach the destination specified by the user with the current SOC value is added to the guided route (S9), and the user is then guided accordingly.
[0080] Then, the processes S24 to S34 are executed on all the charging facility candidates extracted in S23, and after selecting all the charging facility candidates to be charged, the process proceeds to S35.
[0081] In S35, the CPU 21 reads the current value of the remaining power P stored in the flash memory, that is, the expected SOC value after charging at a candidate charging facility along the guided route according to the charging plan (at the point when charging is completed at the last candidate charging facility selected as the target), and determines whether or not there is a shortage of energy required to travel from the last candidate charging facility to the destination.
[0082] Then, if it is determined that the remaining power P is sufficient to meet the energy requirements for traveling to the destination (S35: YES), it is confirmed that the destination can be reached using the planned charging schedule (S36). After that, the planned charging schedule is finalized, and the guidance route is modified as necessary according to the charging schedule (S8), and then the user is guided. The charging schedule should include information specifying the charging facilities selected in S27 and S31 and the charging time at those facilities (maximum charging time), as well as the planned time to start charging at those facilities. However, the charging schedule may only specify the charging facilities to be charged and their order.
[0083] On the other hand, if it is determined that the remaining power P is insufficient for the energy required to travel to the destination (S35: NO), it is determined that the destination cannot be reached with the planned charging schedule (S37). Subsequently, information indicating that the destination specified by the user cannot be reached with the current SOC value is added to the guided route (S9), and the user is guided accordingly.
[0084] As described in detail above, the information provision server 1 and the computer program executed by the information provision server 1 according to this embodiment acquire the location of candidate charging facilities (S23) among charging facilities capable of charging the on-board battery 8 that supplies power to the drive source of the vehicle 4, acquire the current remaining energy amount of the on-board battery 8 equipped with the vehicle (S3), estimate the remaining energy amount of the on-board battery when the vehicle arrives at each charging facility candidate based on the current remaining energy amount of the on-board battery 8, the current location of the vehicle, and the location of the charging facility candidate (S24), and select as the target for charging the charging facility candidate, prioritizing charging facilities that are reachable by the vehicle and whose remaining energy amount of the on-board battery 8 when it arrives at the charging facility candidate falls within a set range based on a threshold that activates the protection function (S27), thereby enabling the user to perform efficient charging. Furthermore, if there are multiple charging station candidates that are reachable by the vehicle and where the remaining energy level of the onboard battery upon arrival at the charging station candidate falls within the set range, the charging station candidate closest to the vehicle's current location will be prioritized for charging (S27). Therefore, if there is a charging station candidate that is reachable by the vehicle and capable of efficient charging, priority will be given to charging as soon as possible. As a result, the risk of insufficient battery charge can be reduced as much as possible. Furthermore, for charging facility candidates that are reachable by the vehicle but where the remaining energy of the onboard battery 8 upon arrival would not fall within the set range, these charging facility candidates are selected as targets for charging if charging is not performed there and the vehicle would not be able to reach the next charging facility candidate or the destination (S31). This allows for efficient charging while also enabling charging that disregards charging efficiency if charging is necessary to reach the destination. Furthermore, the maximum charging time set for each charging facility candidate is also acquired. Based on the remaining energy of the vehicle's battery upon arrival at the charging facility candidate and the maximum charging time, the remaining energy of the vehicle's battery after charging at the charging facility candidate is estimated for each charging facility candidate. The set range is defined as the range in which the remaining energy of the vehicle's battery after charging at the charging facility candidate falls below a threshold. This makes it possible to prioritize the selection of charging facility candidates that allow for efficient charging to completion without the protection function activating midway through the charging process.
[0085] It should be noted that the present invention is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of the invention. For example, in this embodiment, the charging plan is provided to the user after it has been formulated, but providing the charging plan is not mandatory. For example, in the case of an autonomous vehicle, the vehicle may start driving automatically according to the charging plan without being provided with the plan.
[0086] Furthermore, in this embodiment, charging facilities along the guided route to the destination (the planned route of the vehicle) are considered as candidate charging facilities. However, if, for example, no destination is set, it is also possible to search for charging facilities within a predetermined distance from the vehicle's current location as candidate charging facilities and perform the processing from S6 onwards on the searched candidate charging facilities. In other words, the present invention does not necessarily presuppose travel to a destination, and can also be applied when the user searches for a nearby charging facility to charge the vehicle as the onboard battery 8 is depleted (when the charging facility is the destination).
[0087] Furthermore, in this embodiment, a navigation device 5, which is an in-vehicle device, is provided as a means of acquiring information about the vehicle 4 and providing information to the user. However, the navigation device 5 is not essential, and instead of the navigation device 5, the user may be provided with a communication terminal, such as a mobile phone, smartphone, or tablet terminal that is connected to the vehicle 4 in a way that enables communication.
[0088] Furthermore, in this embodiment, in the route search processing program shown in Figure 7, the information provision server 1 was the main entity executing the processes related to route search and the search for charging facility candidates (S2 to S9). However, the navigation device 5 may also be configured to execute some or all of these processes. In other words, it is also possible to apply the present invention to a system including the navigation device 5 and the information provision server 1. [Explanation of symbols]
[0089] 1...Information server (driving support system), 2...Information system, 4...Vehicle, 5...Navigation system, 8...Onboard battery, 10...Charging facility, 21...CPU
Claims
1. A charging facility information acquisition means that acquires the location of a candidate charging facility among charging facilities capable of charging an on-board battery that supplies power to the vehicle's drive source, A means for acquiring the current remaining energy amount of the onboard battery equipped in the vehicle, A protection threshold acquisition means for acquiring a charge amount threshold at which a protection function that reduces the charging speed is activated when charging the vehicle's onboard battery, A remaining energy amount estimation means estimates the remaining energy amount of the vehicle battery when the vehicle arrives at the charging facility candidate, based on the current remaining energy amount of the vehicle battery, the current location of the vehicle, and the location of the charging facility candidate, for each charging facility candidate. A driving support device having a charging facility selection means that, from among the candidate charging facilities, prioritizes selecting a candidate charging facility as the target for charging if it is reachable by the vehicle and the remaining energy amount of the on-board battery upon arrival at the candidate charging facility falls within a set range based on the threshold.
2. The aforementioned charging facility selection means is If, among the candidate charging facilities, there are multiple candidate charging facilities that are reachable by the vehicle and whose remaining energy level of the on-board battery upon arrival at the candidate charging facility falls within the set range, the driving support device according to claim 1, which prioritizes selecting the candidate charging facility closest to the vehicle's current location as the target for charging.
3. The driving support device according to claim 1, wherein, for charging facility candidates that are reachable by the vehicle but whose remaining energy level of the on-board battery upon arrival at the charging facility candidate is not within the set range, the vehicle selects that charging facility candidate as a target for charging if charging is not performed at that charging facility candidate and the vehicle cannot reach the next charging facility candidate or the destination.
4. The charging facility information acquisition means also acquires the maximum charging time set for the candidate charging facility. The system includes a means for estimating the amount of remaining energy after charging, which estimates the amount of remaining energy in the vehicle's battery after charging if the vehicle were to charge at the charging facility candidate, based on the amount of remaining energy in the vehicle's battery upon arrival at the charging facility candidate and the maximum charging time. The driving support device according to any one of claims 1 to 3, wherein the setting range is a range in which the amount of remaining energy of the on-board battery after charging when the vehicle is charged at the candidate charging facility is less than or equal to the threshold.