Route searching method and route searching device

Abstract

This route searching method for searching for a route of a vehicle to a destination predicts the input / output of a battery of the vehicle up to the destination, calculates an input upper limit value of the battery, and searches for a route having the lowest energy consumption amount up to the destination on the basis of the input / output of the battery and the input upper limit value of the battery.

Description

Route Search Method and Route Search Device

[0001] The present invention relates to a route search method and a route search device.

[0002] A method for searching for a route to a vehicle's destination is known (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2011-59921

[0004] In the energy consumption prediction method (route search method) described in Patent Document 1, a route is searched based on the predicted energy consumption, but the input / output of the vehicle's battery and the input limit or output limit of the battery are not considered. Therefore, it is not possible to search for a route taking into account the influence when the input / output of the battery is restricted.

[0005] An object of the present invention is to provide a route search method and a route search device capable of searching for a route taking into account the influence when the input / output of the battery is restricted.

[0006] One aspect of the present invention predicts the input / output of a vehicle's battery to a destination, and searches for a route that minimizes the energy consumption to the destination based on the input / output of the battery and the input upper limit value of the battery.

[0007] One aspect of the present invention predicts the input / output of a vehicle's battery to a destination, and searches for a route that minimizes the decrease in the running performance of the vehicle to the destination due to the output limit of the battery based on the input / output of the battery and the output upper limit value of the battery.

[0008] It is a schematic configuration diagram of a route search system including a route search device according to an embodiment. It is a diagram showing the relationship between the SOC of the battery and the input upper limit value for each battery temperature. It is a flowchart of a route search method according to an embodiment. It is a time chart of the input / output, SOC, and temperature of the battery. It is a time chart of the input / output, input limit value, and output limit value of the battery. It is a diagram showing the difference in energy consumption depending on whether or not battery input / output restrictions are considered. It is a schematic configuration diagram of a route search system including a route search device according to a modified example.

[0009] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram of a route search system 1 including a navigation device 30 as a route search device. The route search system 1 comprises a server 10, a vehicle 20, and a navigation device 30. The server 10 and the navigation device 30 are able to communicate with each other via a network 40.

[0010] Server 10 is implemented by a computer equipped with a storage device 11 such as ROM (Read Only Memory) and RAM (Random Access Memory), a processing unit 12 such as a CPU (Central Processing Unit) and GPU (Central Graphics Processing Unit), and an input / output unit such as an input / output interface. For example, it can be configured as a navigation server or a database server. Server 10 stores map information, statistical information associated with the map information, and driving environment information in the storage device 11 and outputs this information to the navigation device 30.

[0011] Map information contains road information associated with each point, and road information is defined by nodes, links connecting nodes, and identification numbers for nodes and links. For each link's identification information, road information is stored associated with the location of intersections, the direction of entry into intersections, the type of intersection, and other information about intersections, as well as road type such as expressways and toll roads, road width, road shape, speed limit, elevation, average gradient, and other information about roads. Statistical information is stored associated with each link's identification information, including the statistical average speed of vehicles traveling on the road section identified by that identification number. Driving environment information includes weather information and traffic information. Weather information includes, for example, outside temperature, solar radiation, and wind speed. Traffic information includes, for example, traffic volume, congestion information, and construction information for the road section identified by the link's identification information, as well as tolls for expressways and toll roads.

[0012] Vehicle 20 is an electric vehicle that generates its driving force and regenerative braking force (hereinafter also referred to as braking force) using an electric drive source, and in this embodiment it is an electric vehicle. Vehicle 20 includes a battery 21, a braking force generating device 22, an HVAC (Heating-Ventilation-Air Conditioning) 23, a battery temperature control circuit 24, a battery controller 25, and an EV controller 26.

[0013] The battery 21 is a rechargeable battery, and is composed of, for example, a lithium-ion battery or a nickel-metal hydride battery. The temperature, voltage, and current of the battery 21 are detected by sensors and output to the battery controller 25.

[0014] The braking and driving force generating device 22 is controlled by the EV controller 26 and generates driving and braking forces for the vehicle 20. The braking and driving force generating device 22 includes an electric motor as a drive source powered by the battery 21, a reduction gear that reduces the output of the electric motor and transmits it to the wheels, and an inverter that performs driving and regenerative operations of the electric motor.

[0015] HVAC23 is an air conditioning control system for the vehicle 20, which adjusts the temperature inside the vehicle to reach an air conditioning set temperature operated by the occupants of the vehicle 20. HVAC23 includes a heat pump that includes an evaporator for cooling the air inside the vehicle, a condenser for heating the air inside the vehicle, an outdoor heat exchange means that functions as both the evaporator and the condenser, and a chiller that performs heat exchange with the battery temperature control circuit 24.

[0016] The battery temperature control circuit 24 is a circuit that circulates a heat exchange medium to adjust the temperature of the battery 21. The battery temperature control circuit 24 exchanges heat with the heat pump via the chiller of the HVAC 23, and adjusts the temperature of the battery 21 by absorbing or releasing heat from the heat pump.

[0017] The battery controller 25 monitors the state of the battery 21 and limits its input and output. Based on the temperature, voltage, and current of the battery 21, the battery controller 25 calculates the State of Charge (SOC) of the battery 21 and outputs the calculated SOC along with the temperature of the battery 21 to the EV controller 26.

[0018] The EV controller 26 controls the braking force generating device 22, the battery temperature control circuit 24, and the HVAC 23. The EV controller 26 receives the temperature and SOC of the battery 21 from the battery controller 25, and the air conditioning set temperature and outside temperature from the HVAC 23, and outputs these inputs to the navigation device 30.

[0019] The navigation device 30 is implemented by a computer that includes, for example, a storage device 31 such as ROM and RAM, a computing device 32 such as a CPU and GPU, and an input / output unit such as an input / output interface. The server 10 and the EV controller 26 are electrically or communicatively connected to the navigation device 30.

[0020] The navigation device 30 includes a storage device 31, a processing unit 32, a position sensor 38A such as a GNSS (Global Navigation Satellite System) sensor, a display 38B as an output device, and a speaker 38C as an output device. The navigation device 30 acquires map information and driving environment information within a predetermined distance around the vehicle 20 from the server 10, and displays the map information and driving environment information on the display 38B or outputs it as sound from the speaker 38C. Furthermore, when a destination or waypoint is set by the occupant, the navigation device 30 searches for a route from the current position detected by the position sensor 38A to the destination, and notifies the occupant of the searched route by displaying it on the display 38B or by outputting it as sound from the speaker 38C.

[0021] The storage device 31 stores computer programs for operating the navigation device 30, various maps used for route searching, and various parameter values. Examples of maps stored in the storage device 31 include a map showing the relationship between the battery 21's State of Control (SOC) and its input upper limit or output upper limit for each temperature of the battery 21. Parameter values ​​stored in the storage device 31 include vehicle characteristic values ​​such as the mass of the vehicle 20, the capacity and thermal capacity of the battery 21, and various threshold values.

[0022] The arithmetic unit 32 is a processor and includes a battery input / output prediction unit 33, a battery state prediction unit 34, an input / output upper limit calculation unit 35, a path search unit 36, and an energy consumption conversion unit 37.

[0023] The battery input / output prediction unit 33 predicts the input and output of the battery 21 to the destination. For each link of road information to the destination, that is, for each road section identified by the link identification information, the battery input / output prediction unit 33 predicts the input and output of the battery 21 based on, for example, the load due to the vehicle 20's driving resistance, acceleration resistance, and gradient resistance, the electric motor's losses, the battery 21's internal losses, the load of auxiliary equipment such as headlights, the load of the battery temperature control circuit 24, the load of the HVAC 23, and the air conditioning load due to solar radiation. The battery input / output prediction unit 33 may use experimental values ​​stored in advance in the storage device 31 as these load and loss values, or it may obtain the statistical average value of each value for each road information link from the server 10, or it may calculate them. The load due to the vehicle 20's driving resistance is determined according to the vehicle 20's speed, and the load due to acceleration resistance is determined according to the vehicle 20's mass and speed. The load due to gradient resistance is determined according to the vehicle 20's mass and road gradient. The losses of the electric motor are determined according to the rotational speed and torque of the electric motor, and the internal losses of the battery 21 are determined according to the temperature, current, and state of charge (SOC) of the battery 21. The air conditioning load is determined according to the outside temperature and the air conditioning set temperature.

[0024] The input and output of battery 21 can take positive and negative values; a positive value indicates the output of battery 21, and a negative value indicates the input of battery 21. The input to battery 21 occurs when regenerative power from the regenerative operation of the electric motor charges battery 21, or when battery 21 is charged by an external charging device.

[0025] The battery state prediction unit 34 predicts the state of the battery 21 up to the destination. In this embodiment, the battery state prediction unit 34 predicts the temperature and SOC of the battery 21 for each road information link. The battery state prediction unit 34 predicts the SOC of the battery 21 by dividing the input / output of the battery 21 predicted by the battery input / output prediction unit 33 by the capacity of the battery 21. The battery state prediction unit 34 also predicts the temperature of the battery 21 by integrating the temperature change of the battery 21 for each link with the temperature of the battery 21 input from the battery controller 25. The temperature change of the battery 21 for each link can be obtained, for example, by dividing the sum of the self-heating amount of the battery 21 for each link, the heating or cooling amount by the battery temperature control circuit 24, and the amount of heat dissipated from the battery 21 to the outside air by the thermal capacity of the battery 21. The battery state prediction unit 34 may use experimental values ​​stored in advance in the storage device 31 as these values, or it may obtain the statistical average value of each value for each road information link from the server 10, or it may obtain them by calculation. The temperature change of the battery 21 is determined according to the temperature, current, and state of temperature (SOC) of the battery 21, and the amount of heat dissipated from the battery 21 to the outside air is determined according to the ambient temperature and the air conditioning set temperature.

[0026] The input / output upper limit calculation unit 35 calculates the input upper limit and output upper limit of the battery 21 based on the temperature and state of charge (SOC) of the battery 21. In this embodiment, as shown in Figure 2, the input / output upper limit calculation unit 35 calculates the input upper limit by referring to a map that defines the relationship between the SOC of the battery 21 and the input upper limit for each temperature of the battery 21. Similarly, the input / output upper limit calculation unit 35 calculates the output upper limit by referring to a map that defines the relationship between the SOC of the battery 21 and the output upper limit for each temperature of the battery 21. In Figure 2, the uppermost line shows the input upper limit when the temperature of the battery 21 is high, and the lower the line, the lower the input upper limit. The input upper limit and output upper limit of the battery 21 increase as the temperature of the battery 21 increases and decrease as the temperature of the battery 21 decreases, within the allowable temperature range.

[0027] In Figure 1, the route search unit 36 ​​searches for a route for the vehicle 20 based on the input / output of the battery 21, the upper limit of the input of the battery 21, and the upper limit of the output of the battery 21, and notifies the searched route via the display 38B and speaker 38C. The route search unit 36 ​​calculates the energy consumption to the destination using the input / output of the battery 21 after limiting the input / output by the upper limit of the input, and searches for the route that minimizes that energy consumption. The energy consumption is obtained by accumulating the input / output energy of the battery 21 for each link over the route to the destination.

[0028] On the other hand, if the input / output of the battery 21 is limited to the upper output limit, the vehicle's driving performance will decrease, causing discomfort to the occupants, and the driving time to the destination will increase accordingly. For this reason, the route search unit 36 ​​also searches for a route that minimizes the decrease in the vehicle's driving performance to the destination due to the battery's output limit, and a route that minimizes the driving time to the destination. For example, if there is a route in which the input / output of the battery 21 does not reach the upper output limit of the battery 21, the route search unit 36 ​​searches for that route as the route with the minimum decrease in driving performance. Otherwise, it calculates the amount of energy that will not be output when the input / output of the battery 21 is limited to the upper output limit of the battery 21, and searches for a route that minimizes this value as the route with the minimum decrease in driving performance. The route search unit 36 ​​also searches for a route that has the lowest fare to the destination.

[0029] The energy consumption conversion unit 37 converts the energy consumption reduced by driving along the route that minimizes energy consumption, that is, the energy consumption reduced by considering the input / output limits of the battery 21, into the charging time or charging cost of the battery 21, and notifies the user via the display 38B or speaker 38C. In other words, the energy consumption conversion unit 37 calculates the difference in energy consumption between when the input / output limits of the battery 21 are considered and when they are not, and converts this difference into the charging time or charging cost of the battery 21 and notifies the user.

[0030] Figure 3 is a flowchart of the route search method executed by the navigation device 30. The routines shown in the flowchart are pre-programmed and installed in the navigation device 30. The navigation device 30 repeatedly executes the following routines in the program's calculation cycle according to the program.

[0031] In step S1 of Figure 3, the navigation device 30 acquires the output of the server 10, the navigation device 30, and the EV controller 26, namely driving environment information including map information, statistical information, weather information, and traffic information, the current position and destination of the vehicle 20, the temperature and SOC of the battery 21, the air conditioning set temperature, and the outside temperature. At this time, for each road information link in the map information, the average gradient and statistical average speed of the road section identified by the link are also acquired.

[0032] In step S2, the battery input / output prediction unit 33 predicts the input / output of the battery 21 for each road information link.

[0033] In step S3, the battery state prediction unit 34 predicts the temperature and SOC of the battery 21 for each road information link.

[0034] Figure 4 is a time chart showing the input / output, temperature, and SOC of the battery 21 when traveling along different routes toward the same destination. In Figure 4, the values ​​when traveling along route A are shown as dashed lines, and the values ​​when traveling along route B are shown as solid lines. As shown in Figure 4, the battery input / output prediction unit 33 and the battery state prediction unit 34 predict the input / output, temperature, and SOC of the battery 21 for each route to the destination.

[0035] Returning to Figure 3, in the following step S4, the input / output upper limit calculation unit 35 refers to the map stored in the storage device 31 and calculates the input upper limit and output upper limit of the battery 21 for each road information link based on the temperature and SOC of the battery 21.

[0036] In step S5, the route search unit 36 ​​searches for a route that minimizes the energy consumption of the battery 21 to the destination and minimizes the reduction in the driving performance of the vehicle 20 to the destination, based on the input / output of the battery 21, the upper limit of the input of the battery 21, and the upper limit of the output of the battery 21, and notifies the user of the route. The route search unit 36 ​​also searches for and notifies the route that has the shortest travel distance to the destination and the route that has the lowest fare to the destination.

[0037] Figure 5 is a time chart of the input / output, input upper limit, and output upper limit of battery 21. Similar to Figure 4, Figure 5 shows the input / output of battery 21 when traveling along route A and when traveling along route B. The input limit and output limit of battery 21 are also shown.

[0038] As shown in Figure 5, when traveling along route A, the output of battery 21 is smaller and the input is larger than when traveling along route B, so at first glance it seems that route A consumes less energy. In fact, if the limitations of input and output of battery 21 are not considered, route A consumes less energy, as shown in Figure 6 which illustrates the difference in energy consumption.

[0039] However, as shown in Figure 5, when traveling along route A, the input to battery 21 exceeds the input limit, and the excess is not actually input to battery 21. In contrast, when traveling along route B, the input to battery 21 does not exceed the input limit, and all of it is input to battery 21. Therefore, considering the input / output limits of battery 21, as shown in Figure 6, route B consumes less energy than route A. Accordingly, the route search unit 36 ​​searches for route B, not route A, as the route that minimizes the energy consumption of battery 21 to the destination.

[0040] Returning to Figure 3, in the following step S6, the energy consumption conversion unit 37 converts the energy consumption reduced by driving along the route with the least energy consumption into the charging time or cost of the battery 21, based on the average charging speed and average charging cost, and notifies the user of these values ​​via the display 38B and speaker 38C.

[0041] According to the above embodiment, the system searches for a route that minimizes energy consumption to the destination based on the input / output of the battery 21 and the upper limit of the battery 21's input. This allows the system to search for a route while taking into account the impact when the input / output of the battery 21 is limited.

[0042] According to the embodiment, the energy consumption reduced by traveling along the route with the minimum energy consumption is converted into the charging time required for the battery 21 or the charging amount and notified, so that the passengers of the vehicle 20 can recognize the advantages of the route explored in consideration of the input limit of the battery 21.

[0043] According to the embodiment, based on the input / output of the battery 21 and the output upper limit value of the battery 21, a route with the least reduction in the driving performance of the vehicle 20 to the destination is explored, so that the route can be explored in consideration of the influence when the input / output of the battery 21 is restricted.

[0044] As described above, the best configuration, method, etc. for implementing the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, the present invention is mainly illustrated and described with respect to specific embodiments, but without departing from the scope of the technical idea and object of the present invention, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations. In addition, the descriptions limiting the shape, material, etc. disclosed above are exemplified for easy understanding of the present invention and do not limit the present invention. Therefore, the description using the names of members with some or all of the limitations on those shapes, materials, etc. removed is included in the present invention.

[0045] As shown in FIG. 7, the route search system 1A may include a route search device 50 configured separately from the navigation device 30A. The route search device 50 may be an in-vehicle device different from the navigation device 30, or may be a portable terminal such as a smartphone or a tablet. The route search device 50 is realized by a computer including a storage device 51 such as a ROM and a RAM, an arithmetic device 52 such as a CPU and a GPU, and an input / output unit such as an input / output interface. Similar to the embodiment, the arithmetic device 52 includes a battery input / output prediction unit 53, a battery state prediction unit 54, an input / output upper limit value calculation unit 55, a route search unit 56, and an energy consumption conversion unit 57.

[0046] The server 10 may be, for example, a cloud server constructed by connecting a plurality of computers via a network 40.

[0047] The control driving force generation device 22 may include an engine, drive a generator with the engine to supply power to the electric motor, and drive the wheels with the electric motor, or may drive the wheels with both the electric motor and the engine. That is, the vehicle 20 may be a so-called series hybrid vehicle or a parallel hybrid vehicle.

[0048] The navigation device 30 may, for example, acquire map information and statistical information recorded on a recording medium mounted on the vehicle 20 from the recording medium.

[0049] The route search device may be the server 10. In this case, the storage device 11 and the arithmetic device 12 of the server 10 are configured like the storage device 31 and the arithmetic device 32 of the navigation device 30.

[0050] The route search method may be executed by the server 10, may be executed by the navigation device 30, may be executed by an in-vehicle device different from the navigation device 30, or may be executed by a portable terminal such as a smartphone or a tablet.

[0051] 20... Vehicle, 21... Battery, 30... Navigation device (route search device)

Claims

1. A route search method for searching for a route for a vehicle to a destination, comprising: predicting the input and output of the vehicle's battery to the destination; calculating the upper limit of the battery's input; and searching for a route that minimizes energy consumption to the destination based on the battery's input and output and the upper limit of the battery's input.

2. A route search method according to claim 1, wherein the amount of energy consumption reduced by traveling along the route that minimizes energy consumption is converted into the battery charging time or charging cost and reported.

3. A route search method for searching for a route for a vehicle to a destination, comprising: predicting the input and output of the vehicle's battery to the destination; calculating the upper limit of the battery's output; and searching for a route that minimizes the reduction in the vehicle's driving performance to the destination due to the battery's output limitation, based on the battery's input and output and the upper limit of the battery's output.

4. A route search device for searching for a route for a vehicle to a destination, comprising: a battery input / output prediction unit that predicts the input and output of the vehicle's battery to the destination; an input / output upper limit calculation unit that calculates the upper limit of the battery's input and output; and a route search unit that searches for a route to the destination that minimizes energy consumption based on the battery's input and output and the upper limit of the battery's input, or searches for a route to the destination that minimizes the reduction in the vehicle's driving performance to the destination due to the battery's output limitation based on the battery's input and output and the upper limit of the battery's output.

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